A protein which is a subunit of RNA polymerase. It effects initiation of specific RNA chains from DNA.
Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.
A class of cell surface receptors recognized by its pharmacological profile. Sigma receptors were originally considered to be opioid receptors because they bind certain synthetic opioids. However they also interact with a variety of other psychoactive drugs, and their endogenous ligand is not known (although they can react to certain endogenous steroids). Sigma receptors are found in the immune, endocrine, and nervous systems, and in some peripheral tissues.
A DNA-directed RNA polymerase found in BACTERIA. It is a holoenzyme that consists of multiple subunits including sigma factor 54.
Proteins found in any species of bacterium.
Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).
A species of gram-positive bacteria that is a common soil and water saprophyte.
In eukaryotes, a genetic unit consisting of a noncontiguous group of genes under the control of a single regulator gene. In bacteria, regulons are global regulatory systems involved in the interplay of pleiotropic regulatory domains and consist of several OPERONS.
The functional hereditary units of BACTERIA.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.
Heat and stain resistant, metabolically inactive bodies formed within the vegetative cells of bacteria of the genera Bacillus and Clostridium.
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Proteins obtained from ESCHERICHIA COLI.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
A constellation of responses that occur when an organism is exposed to excessive heat. Responses include synthesis of new proteins and regulation of others.
Catalytically active enzymes that are formed by the combination of an apoenzyme (APOENZYMES) and its appropriate cofactors and prosthetic groups.
Proteins which are synthesized in eukaryotic organisms and bacteria in response to hyperthermia and other environmental stresses. They increase thermal tolerance and perform functions essential to cell survival under these conditions.
A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.
Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
A form-genus of unicellular CYANOBACTERIA in the order Chroococcales. None of the strains fix NITROGEN, there are no gas vacuoles, and sheath layers are never produced.
Mutagenesis where the mutation is caused by the introduction of foreign DNA sequences into a gene or extragenic sequence. This may occur spontaneously in vivo or be experimentally induced in vivo or in vitro. Proviral DNA insertions into or adjacent to a cellular proto-oncogene can interrupt GENETIC TRANSLATION of the coding sequences or interfere with recognition of regulatory elements and cause unregulated expression of the proto-oncogene resulting in tumor formation.
The first nucleotide of a transcribed DNA sequence where RNA polymerase (DNA-DIRECTED RNA POLYMERASE) begins synthesizing the RNA transcript.
Salts of alginic acid that are extracted from marine kelp and used to make dental impressions and as absorbent material for surgical dressings.
The in vitro fusion of GENES by RECOMBINANT DNA techniques to analyze protein behavior or GENE EXPRESSION REGULATION, or to merge protein functions for specific medical or industrial uses.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.
The first mixed agonist-antagonist analgesic to be marketed. It is an agonist at the kappa and sigma opioid receptors and has a weak antagonist action at the mu receptor. (From AMA Drug Evaluations Annual, 1991, p97)
The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.
A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.
A soil-dwelling actinomycete with a complex lifecycle involving mycelial growth and spore formation. It is involved in the production of a number of medically important ANTIBIOTICS.
A whiplike motility appendage present on the surface cells. Prokaryote flagella are composed of a protein called FLAGELLIN. Bacteria can have a single flagellum, a tuft at one pole, or multiple flagella covering the entire surface. In eukaryotes, flagella are threadlike protoplasmic extensions used to propel flagellates and sperm. Flagella have the same basic structure as CILIA but are longer in proportion to the cell bearing them and present in much smaller numbers. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
A group of enzymes that catalyzes the hydrolysis of terminal, non-reducing beta-D-galactose residues in beta-galactosides. Deficiency of beta-Galactosidase A1 may cause GANGLIOSIDOSIS, GM1.
Term used to designate tetrahydroxy aldehydic acids obtained by oxidation of hexose sugars, i.e. glucuronic acid, galacturonic acid, etc. Historically, the name hexuronic acid was originally given to ascorbic acid.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
A sugar acid formed by the oxidation of the C-6 carbon of GLUCOSE. In addition to being a key intermediate metabolite of the uronic acid pathway, glucuronic acid also plays a role in the detoxification of certain drugs and toxins by conjugating with them to form GLUCURONIDES.
Presence of warmth or heat or a temperature notably higher than an accustomed norm.
The genetic complement of a BACTERIA as represented in its DNA.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
A species of gram-negative bacteria and nitrogen innoculant of PHASEOLUS VULGARIS.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
A protein with a molecular weight of 40,000 isolated from bacterial flagella. At appropriate pH and salt concentration, three flagellin monomers can spontaneously reaggregate to form structures which appear identical to intact flagella.
The unfavorable effect of environmental factors (stressors) on the physiological functions of an organism. Prolonged unresolved physiological stress can affect HOMEOSTASIS of the organism, and may lead to damaging or pathological conditions.
Guanosine 5'-diphosphate 2'(3')-diphosphate. A guanine nucleotide containing four phosphate groups. Two phosphate groups are esterified to the sugar moiety in the 5' position and the other two in the 2' or 3' position. This nucleotide serves as a messenger to turn off the synthesis of ribosomal RNA when amino acids are not available for protein synthesis. Synonym: magic spot I.
The pressure required to prevent the passage of solvent through a semipermeable membrane that separates a pure solvent from a solution of the solvent and solute or that separates different concentrations of a solution. It is proportional to the osmolality of the solution.
Self-replicating cytoplasmic organelles of plant and algal cells that contain pigments and may synthesize and accumulate various substances. PLASTID GENOMES are used in phylogenetic studies.
A species of nonpathogenic fluorescent bacteria found in feces, sewage, soil, and water, and which liquefy gelatin.
A large family of signal-transducing adaptor proteins present in wide variety of eukaryotes. They are PHOSPHOSERINE and PHOSPHOTHREONINE binding proteins involved in important cellular processes including SIGNAL TRANSDUCTION; CELL CYCLE control; APOPTOSIS; and cellular stress responses. 14-3-3 proteins function by interacting with other signal-transducing proteins and effecting changes in their enzymatic activity and subcellular localization. The name 14-3-3 derives from numerical designations used in the original fractionation patterns of the proteins.
An opioid analgesic with actions and uses similar to MORPHINE. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1095)
The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
A complex of cyclic peptide antibiotics produced by the Tracy-I strain of Bacillus subtilis. The commercial preparation is a mixture of at least nine bacitracins with bacitracin A as the major constituent. It is used topically to treat open infections such as infected eczema and infected dermal ulcers. (From Goodman and Gilman, The Pharmacological Basis of Therapeutics, 8th ed, p1140)
Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.
Proteases that contain proteolytic core domains and ATPase-containing regulatory domains. They are usually comprised of large multi-subunit assemblies. The domains can occur within a single peptide chain or on distinct subunits.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A species of gram-positive, aerobic bacteria that produces TUBERCULOSIS in humans, other primates, CATTLE; DOGS; and some other animals which have contact with humans. Growth tends to be in serpentine, cordlike masses in which the bacilli show a parallel orientation.
A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.
Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.
Genes which regulate or circumscribe the activity of other genes; specifically, genes which code for PROTEINS or RNAs which have GENE EXPRESSION REGULATION functions.
A species of gram-negative, aerobic bacteria that causes formation of root nodules on some, but not all, types of sweet clover, MEDICAGO SATIVA, and fenugreek.
The genetic unit consisting of three structural genes, an operator and a regulatory gene. The regulatory gene controls the synthesis of the three structural genes: BETA-GALACTOSIDASE and beta-galactoside permease (involved with the metabolism of lactose), and beta-thiogalactoside acetyltransferase.
An actinomycete from which the antibiotic CHLORTETRACYCLINE is obtained.
A sulfhydryl reagent which oxidizes sulfhydryl groups to the disulfide form. It is a radiation-sensitizing agent of anoxic bacterial and mammalian cells.
A theoretical representative nucleotide or amino acid sequence in which each nucleotide or amino acid is the one which occurs most frequently at that site in the different sequences which occur in nature. The phrase also refers to an actual sequence which approximates the theoretical consensus. A known CONSERVED SEQUENCE set is represented by a consensus sequence. Commonly observed supersecondary protein structures (AMINO ACID MOTIFS) are often formed by conserved sequences.
The determination of the pattern of genes expressed at the level of GENETIC TRANSCRIPTION, under specific circumstances or in a specific cell.
An integration host factor that was originally identified as a bacterial protein required for the integration of bacteriophage Q beta (ALLOLEVIVIRUS). Its cellular function may be to regulate mRNA stability and processing in that it binds tightly to poly(A) RNA and interferes with ribosome binding.
A species of gram-positive bacteria in the family Clostridiaceae, used for the industrial production of SOLVENTS.
Hybridization of a nucleic acid sample to a very large set of OLIGONUCLEOTIDE PROBES, which have been attached individually in columns and rows to a solid support, to determine a BASE SEQUENCE, or to detect variations in a gene sequence, GENE EXPRESSION, or for GENE MAPPING.
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
A protein which effects termination of RNA synthesis during the genetic transcription process by dissociating the ternary transcription complex RNA;-RNA POLYMERASE DNA at the termination of a gene.
Chemical compounds which yield hydrogen ions or protons when dissolved in water, whose hydrogen can be replaced by metals or basic radicals, or which react with bases to form salts and water (neutralization). An extension of the term includes substances dissolved in media other than water. (Grant & Hackh's Chemical Dictionary, 5th ed)
A family of signal transducing adaptor proteins that control the METABOLISM of NITROGEN. They are primarily found in prokaryotes.
A species of gliding bacteria found on soil as well as in surface fresh water and coastal seawater.
A species of gram-negative, aerobic bacteria that consist of slender vibroid cells.
A species of gram-negative, aerobic bacteria isolated from soil and water as well as clinical specimens. Occasionally it is an opportunistic pathogen.
The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.
Proteins isolated from the outer membrane of Gram-negative bacteria.
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
A sub-class of PEPTIDE HYDROLASES that act only near the ends of polypeptide chains.
Enzymes that catalyze the release of mononucleotides by the hydrolysis of the terminal bond of deoxyribonucleotide or ribonucleotide chains.
Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.
A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.
A genus of gram-negative, aerobic, rod-shaped bacteria usually containing granules of poly-beta-hydroxybutyrate. They characteristically invade the root hairs of leguminous plants and act as intracellular symbionts.
The first DNA-binding protein motif to be recognized. Helix-turn-helix motifs were originally identified in bacterial proteins but have since been found in hundreds of DNA-BINDING PROTEINS from both eukaryotes and prokaryotes. They are constructed from two alpha helices connected by a short extended chain of amino acids, which constitute the "turn." The two helices are held at a fixed angle, primarily through interactions between the two helices. (From Alberts et al., Molecular Biology of the Cell, 3d ed, p408-9)
Ability of a microbe to survive under given conditions. This can also be related to a colony's ability to replicate.
Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.
Permanganic acid (HMnO4), potassium salt. A highly oxidative, water-soluble compound with purple crystals, and a sweet taste. (From McGraw-Hill Dictionary of Scientific and Technical Information, 4th ed)

Hyperproduction of alpha-hemolysin in a sigB mutant is associated with elevated SarA expression in Staphylococcus aureus. (1/2871)

To evaluate the role of SigB in modulating the expression of virulence determinants in Staphylococcus aureus, we constructed a sigB mutant of RN6390, a prototypic S. aureus strain. The mutation in the sigB gene was confirmed by the absence of the SigB protein in the mutant on an immunoblot as well as the failure of the mutant to activate sigmaB-dependent promoters (e.g., the sarC promoter) of S. aureus. Phenotypic analysis indicated that both alpha-hemolysin level and fibrinogen-binding capacity were up-regulated in the mutant strain compared with the parental strain. The increase in fibrinogen-binding capacity correlated with enhanced expression of clumping factor and coagulase on immunoblots. The effect of the sigB mutation on the enhanced expression of the alpha-hemolysin gene (hla) was primarily transcriptional. Upon complementation with a plasmid containing the sigB gene, hla expression returned to near parental levels in the mutant. Detailed immunoblot analysis as well as a competitive enzyme-linked immunosorbent assay of the cell extract of the sigB mutant with anti-SarA monoclonal antibody 1D1 revealed that the expression of SarA was higher in the mutant than in the parental control. Despite an elevated SarA level, the transcription of RNAII and RNAIII of the agr locus remained unaltered in the sigB mutant. Because of a lack of perturbation in agr, we hypothesize that inactivation of sigB leads to increased expression of SarA which, in turn, modulates target genes via an agr-independent but SarA-dependent pathway.  (+info)

General method of analysis of kinetic equations for multistep reversible mechanisms in the single-exponential regime: application to kinetics of open complex formation between Esigma70 RNA polymerase and lambdaP(R) promoter DNA. (2/2871)

A novel analytical method based on the exact solution of equations of kinetics of unbranched first- and pseudofirst-order mechanisms is developed for application to the process of Esigma70 RNA polymerase (R)-lambdaPR promoter (P) open complex formation, which is described by the minimal three-step mechanism with two kinetically significant intermediates (I1, I2), [equation: see text], where the final product is an open complex RPo. The kinetics of reversible and irreversible association (pseudofirst order, [R] >> [P]) to form long-lived complexes (RPo and I2) and the kinetics of dissociation of long-lived complexes both exhibit single exponential behavior. In this situation, the analytical method provides explicit expressions relating observed rate constants to the microscopic rate constants of mechanism steps without use of rapid equilibrium or steady-state approximations, and thereby provides a basis for interpreting the composite rate constants of association (ka), isomerization (ki), and dissociation (kd) obtained from experiment for this or any other sequential mechanism of any number of steps. In subsequent papers, we apply this formalism to analyze kinetic data obtained in the reversible and irreversible binding regimes of Esigma70 RNA polymerase (R)-lambdaP(R) promoter (P) open complex formation.  (+info)

Transient gene asymmetry during sporulation and establishment of cell specificity in Bacillus subtilis. (3/2871)

Sporulation in Bacillus subtilis is initiated by an asymmetric division generating two cells of different size and fate. During a short interval, the smaller forespore harbors only 30% of the chromosome until the remaining part is translocated across the septum. We demonstrate that moving the gene for sigmaF, the forespore-specific transcription factor, in the trapped region of the chromosome is sufficient to produce spores in the absence of the essential activators SpoIIAA and SpoIIE. We propose that transient genetic asymmetry is the device that releases SpoIIE phosphatase activity in the forespore and establishes cell specificity.  (+info)

The Escherichia coli Ada protein can interact with two distinct determinants in the sigma70 subunit of RNA polymerase according to promoter architecture: identification of the target of Ada activation at the alkA promoter. (4/2871)

The methylated form of the Ada protein (meAda) activates transcription from the Escherichia coli ada, aidB, and alkA promoters with different mechanisms. In this study we identify amino acid substitutions in region 4 of the RNA polymerase subunit sigma70 that affect Ada-activated transcription at alkA. Substitution to alanine of residues K593, K597, and R603 in sigma70 region 4 results in decreased Ada-dependent binding of RNA polymerase to the alkA promoter in vitro and impairs alkA transcription both in vivo and in vitro, suggesting that these residues define a determinant for meAda-sigma70 interaction. In a previous study (P. Landini, J. A. Bown, M. R. Volkert, and S. J. W. Busby, J. Biol. Chem. 273:13307-13312, 1998), we showed that a set of negatively charged amino acids in sigma70 region 4 is involved in meAda-sigma70 interaction at the ada and aidB promoters. However, the alanine substitutions of positively charged residues K593, K597, and R603 do not affect meAda-dependent transcription at ada and aidB. Unlike the sigma70 amino acids involved in the interaction with meAda at the ada and aidB promoters, K593, K597, and R603 are not conserved in sigmaS, an alternative sigma subunit of RNA polymerase mainly expressed during the stationary phase of growth. While meAda is able to promote transcription by the sigmaS form of RNA polymerase (EsigmaS) at ada and aidB, it fails to do so at alkA. We propose that meAda can activate transcription at different promoters by contacting distinct determinants in sigma70 region 4 in a manner dependent on the location of the Ada binding site.  (+info)

An intrinsic DNA curvature found in the cyanobacterium Microcystis aeruginosa K-81 affects the promoter activity of rpoD1 encoding a principal sigma factor. (5/2871)

The rpoD1 gene in the unicellular cyanobacterium Microcystis aeruginosa K-81 encodes a principal sigma factor of RNA polymerase and is transcribed under light and dark conditions to produce multiple monocistronic transcripts. In the 5'-upstream region from rpoD1 Promoter 2, which has a sequence of Escherichia coli type, we found a sequence-directed DNA curvature with an AT-rich sequence. Insertions of 2 to 21 base pairs introduced into the curved center changed a gross geometry of the original curved DNA structure. The rpoD1 promoter activities assayed in vivo by using transcriptional lacZ fusions were correlated with the change in the gross geometry in not only a cyanobacterium but also E. coli. In addition, RNA polymerase binding to the rpoD1 promoter region and the efficiency of the mRNA synthesis from the rpoD1 Promoter 2 were also affected in vitro by the change in the geometry. These results suggest that the tertiary structure of the curved DNA is important for the rpoD1 transcription. The deletion of the center region of the curvature resulted in a considerable reduction of the transcription from Promoter 2 in the cyanobacterium. This report demonstrates that a curved DNA plays a significant role in transcription in cyanobacteria, and that this functional curvature is located in the 5'-upstream region from the rpoD gene, which encodes a principal sigma factor in eubacteria.  (+info)

Bacillus subtilis spore coat. (6/2871)

In response to starvation, bacilli and clostridia undergo a specialized program of development that results in the production of a highly resistant dormant cell type known as the spore. A proteinacious shell, called the coat, encases the spore and plays a major role in spore survival. The coat is composed of over 25 polypeptide species, organized into several morphologically distinct layers. The mechanisms that guide coat assembly have been largely unknown until recently. We now know that proper formation of the coat relies on the genetic program that guides the synthesis of spore components during development as well as on morphogenetic proteins dedicated to coat assembly. Over 20 structural and morphogenetic genes have been cloned. In this review, we consider the contributions of the known coat and morphogenetic proteins to coat function and assembly. We present a model that describes how morphogenetic proteins direct coat assembly to the specific subcellular site of the nascent spore surface and how they establish the coat layers. We also discuss the importance of posttranslational processing of coat proteins in coat morphogenesis. Finally, we review some of the major outstanding questions in the field.  (+info)

Role of the alternative sigma factor sigmaS in expression of the AlkS regulator of the Pseudomonas oleovorans alkane degradation pathway. (7/2871)

The AlkS protein activates transcription from the PalkB promoter, allowing the expression of a number of genes required for the assimilation of alkanes in Pseudomonas oleovorans. We have identified the promoter from which the alkS gene is transcribed, PalkS, and analyzed its expression under different conditions and genetic backgrounds. Transcription from PalkS was very low during the exponential phase of growth and increased considerably when cells reached the stationary phase. The PalkS -10 region was similar to the consensus described for promoters recognized by Escherichia coli RNA polymerase bound to the alternative sigma factor sigmaS, which directs the expression of many stationary-phase genes. Reporter strains containing PalkS-lacZ transcriptional fusions showed that PalkS promoter is very weakly expressed in a Pseudomonas putida strain bearing an inactivated allele of the gene coding for sigmaS, rpoS. When PalkS was transferred to E. coli, transcription started at the same site and expression was higher in stationary phase only if sigmaS-RNA polymerase was present. The low levels of AlkS protein generated in the absence of sigmaS were enough to support a partial induction of the PalkB promoter. The -10 and -35 regions of PalkS promoter also show some similarity to the consensus recognized by sigmaD-RNA polymerase, the primary form of RNA polymerase. We propose that in exponential phase PalkS is probably recognized both by sigmaD-RNA polymerase (inefficiently) and by sigmaS-RNA polymerase (present at low levels), leading to low-level expression of the alkS gene. sigmaS-RNA polymerase would be responsible for the high level of activity of PalkS observed in stationary phase.  (+info)

Characterization of the ssnA gene, which is involved in the decline of cell viability at the beginning of stationary phase in Escherichia coli. (8/2871)

When grown in rich medium, Escherichia coli exhibits a drastic reduction of the number of viable cells at the beginning of stationary phase. The decline of cell viability was retarded by disruption of the ssnA gene, which was identified as a gene subject to RpoS-dependent negative regulation. Moreover, ssnA expression was induced at the time of decline of cell viability at early stationary phase. The viability decline was augmented in the rpoS background, and this augmentation was suppressed by ssnA mutation. Cloning of the ssnA gene in a multicopy plasmid, pBR322, caused small colony formation and slow growth in liquid medium. Cells harboring the ssnA clone showed aberrant morphology that included enlarged and filamentous shapes. The gene product was identified as a 44-kDa soluble protein, but its function could not be deduced by homology searching. From these results, we conclude that ssnA is expressed in response to a phase-specific signal(s) and that its expression level is controlled by RpoS, by a mechanism which may contribute to determination of cell number in the stationary phase.  (+info)

TY - JOUR. T1 - The alternative sigma factor sigma B of Staphylococcus aureus modulates virulence in experimental central venous catheter-related infections.. AU - Ziebuhr, Wilma. PY - 2008/3. Y1 - 2008/3. N2 - The impact of the alternative sigma factor sigma B (SigB) on pathogenesis of Staphylococcus aureus is not conclusively clarified. In this study, a central venous catheter (CVC) related model of multiorgan infection was used to investigate the role of SigB for the pathogenesis of S. aureus infections and biofilm formation in vivo. Analysis of two SigB-positive wild-type strains and their isogenic mutants revealed uniformly that the wild-type was significantly more virulent than the SigB-deficient mutant. The observed difference in virulence was apparently not linked to the capability of the strains to form biofilms in vivo since wild-type and mutant strains were able to produce biofilm layers inside of the catheter. The data strongly indicate that the alternative sigma factor SigB plays a ...
Several alternative sigma factors of M. tuberculosis regulate gene expression in response to stress, including SigH and SigE, which have been shown (SigH) or are hypothesized (SigE) to be regulated by ZASs. Though sigL is also linked to a likely ZAS gene (rslA), we did not identify oxidative or nitrosative stress conditions that either induced expression of this sigma factor or resulted in decreased survival of a sigL mutant relative to wild-type survival. These results suggest that SigL is not a stress response regulator and that other conditions encountered by the bacillus during infection in vivo may activate sigL expression.. By performing microarray analysis followed by primer extension and in vitro transcription experiments, we identified a limited set of genes that are directly regulated by SigL. Despite the small number of regulated promoters, we identified clear −35 and −10 element consensus sequences (TGAACC-N16-CGT) in the promoters recognized by SigL. Though this is similar to ...
Environmental pH stress constitutes a limiting factor for S. meliloti survival and development. The response to acidic pH stress in S. meliloti is versatile and characterized by the differential expression of genes associated with various cellular functions. The purpose of this study was to gain detailed insight into the participation of sigma factors in the complex stress response system of S. meliloti 1021 using pH stress as an effector. In vitro assessment of S meliloti wild type and sigma factor mutants provided first evidence that the sigma factor RpoH1 plays a major role in the pH stress response. Differential expression of genes related to rhizobactin biosynthesis was observed in microarray analyses performed with the rpoH1 mutant at pH 7.0. The involvement of the sigma factor RpoH1 in the regulation of S. meliloti genes upon pH stress was analyzed by comparing time-course experiments of the wild type and the rpoH1 mutant. Three classes of S. meliloti genes could be identified, which were
E. Bouffartigues, I. Si Hadj Mohand, R. Duchesne, O. Maillot, N. Orange, et al.. Insight into the mechanism controlling the activity of the extracytoplasmic function sigma factor SigX in Pseudomonas aeruginosa. XIeme Congrès de la SFM, 2015, PARIS, France. ⟨hal-02386341⟩ ...
The activation of additional promoter sites by production of an alternative sigma subunit for RNA polymerase is a common strategy for the coordinate regulation of gene expression. Many alternative sigma factors control genes for specialized, and often narrowly distributed, functions. For example, most of the alternative sigma factors in Bacillus subtilis control genes necessary for endospore formation. In contrast, the B. subtilis sigma D protein controls the expression of genes important for flagellar-based motility and chemotaxis, a form of locomotion very broadly distributed in the eubacteria. A homologous sigma factor, sigma F, controls a similar group of motility genes in the enteric bacteria. The conservation of both promoter specificity and genetic function in these two regulons allowed us to test the ability of a B. subtilis sigma factor to function within an Escherichia coli host. We demonstrate that expression of the B. subtilis sigD gene restores motility to an E. coli strain mutant ...
Shop Probable RNA polymerase sigma factor ELISA Kit, Recombinant Protein and Probable RNA polymerase sigma factor Antibody at MyBioSource. Custom ELISA Kit, Recombinant Protein and Antibody are available.
Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. Extracytoplasmic function (ECF) sigma factors are held in an inactive form by an anti-sigma factor (RsaM, AC L7N5D7) until released by regulated intramembrane proteolysis (Probable). This sigma factor is required for the synthesis of surface or secreted molecules.
Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. This sigma factor is involved in regulation of expression of heat shock genes. Intracellular concentration of free RpoH protein increases in response to heat shock, which causes association with RNA polymerase (RNAP) and initiation of transcription of heat shock genes, including numerous global transcriptional regulators and genes involved in maintaining membrane functionality and homeostasis. RpoH is then quickly degraded, leading to a decrease in the rate of synthesis of heat shock proteins and shut-off of the heat shock response.
sigma B, a secondary sigma factor of Bacillus subtilis, was found to increase 5- to 10-fold when cultures were shifted from 37 to 48 degrees C. Western blot (immunoblot) analyses, in which monoclonal antibodies specific for the sigB operon products RsbV, RsbW, and sigma B were used to probe extracts from wild-type and mutant B. subtilis strains, revealed that all three proteins increased coordinately after heat shock and that this increase was dependent on sigma B but not RsbV, a positive regulator normally essential for sigma B-dependent sigB expression. Nuclease protection experiments of RNA synthesized after heat shock supported the notion that the shift to 48 degrees C enhanced transcription from the sigB operons sigma B-dependent promoter. The level of mRNA initiating at the sigma B-dependent ctc promoter was also seen to increase approximately 5- to 10-fold after heat shock. Pulse-labeling of the proteins synthesized after a shift to 48 degrees C demonstrated that sigB wild-type and ...
The cell envelope of bacteria is of pivotal importance for growth and survival, and hence it is often the target of antimicrobial compounds. One of the main components involved in CESRs are extracytoplasmic function (ECF) [sigma] factors. The genome of B. subtilis encodes for seven ECF [sigma] factors, [sigma]M, [sigma]W, [sigma]X, [sigma]Y, [sigma]V, [sigma]Z and [sigma]YlaC. Several studies have been conducted to understand the role that these ECF [sigma] factors play in CESR in B. subtilis, one of the challenges found is that they display significant redundancy within their regulons. In this study, we have performed an in depth analysis of one of the ECF [sigma] factors of B. subtilis, [sigma]V, which had been previously uncharacterized. We have described the regulon of [sigma]V, the role that it plays in lysozyme resistance, and provided evidence for a novel promoter element important for [sigma]V recognition. Additionally, we have studied the role that [sigma]M plays in moenomycin ...
The general stress response comprises approximately 200 genes and is driven by the alternative sigma factor SigB. Besides the process of sporulation with approximately 500 involved gene products under initial control of Spo0A are the two most significant and extensive cellular responses that can be observed in B. subtilis. The general stress response provides vegetative growing as well as non-growing and non-sporulating cells with a comprehensive cross-protective and preventive multiple stress resistance to various hostile environmental conditions. In contrast, the endospore is the most resistant but also dormant cell type produced by B. subtilis. The scope of this study was the identification of regulatory cascades driven by the general stress response sigma factor SigB to further elucidate the structure and function of the general stress regulon itself and to uncover potential intersections between the SigB response and other major developmental programs in the regulatory network of B. ...
Background The expression of genes in Corynebacterium glutamicum, a Gram-positive non-pathogenic bacterium used mainly for the industrial production of amino acids, is regulated by seven different sigma factors of RNA polymerase, including the stress-responsive ECF-sigma factor SigH. The sigH gene is located in a gene cluster together with the rshA gene, putatively encoding an anti-sigma factor. The aim of this study was to analyze the transcriptional regulation of the sigH and rshA gene cluster and the effects of RshA on the SigH regulon, in order to refine the model describing the role of SigH and RshA during stress response. Results Transcription analyses revealed that the sigH gene and rshA gene are cotranscribed from four sigH housekeeping promoters in C. glutamicum. In addition, a SigH-controlled rshA promoter was found to only drive the transcription of the rshA gene. To test the role of the putative anti-sigma factor gene rshA under normal growth conditions, a C. glutamicum rshA deletion ...
Lien vers Pubmed [PMID] - 29229758. Biochem. J. 2018 01;475(1):341-354. In bacteria, one primary and multiple alternative sigma (σ) factors associate with the RNA polymerase core enzyme (E) to form holoenzymes (Eσ) with different promoter recognition specificities. The alternative σ factor RpoS/σ is produced in stationary phase and under stress conditions and reprograms global gene expression to promote bacterial survival. To date, the three-dimensional structure of a full-length free σ factor remains elusive. The current model suggests that extensive interdomain contacts in a free σ factor result in a compact conformation that masks the DNA-binding determinants of σ, explaining why a free σ factor does not bind double-stranded promoter DNA efficiently. Here, we explored the solution conformation of σ using amide hydrogen/deuterium exchange coupled with mass spectrometry, NMR, analytical ultracentrifugation and molecular dynamics. Our data strongly argue against a compact conformation ...
TY - JOUR. T1 - The alternative sigma factor sigh regulates major components of oxidative and heat stress responses in Mycobacterium tuberculosis. AU - Raman, S.. AU - Song, T.. AU - Puyang, X.. AU - Bardarov, S.. AU - Jacobs, Jr. AU - Husson, R. N.. PY - 2001. Y1 - 2001. N2 - Mycobacterium tuberculosis is a specialized intracellular pathogen that must regulate gene expression to overcome stresses produced by host defenses during infection. SigH is an alternative sigma factor that we have previously shown plays a role in the response to stress of the saprophyte Mycobacterium smegmatis. In this work we investigated the role of sigH in the M. Tuberculosis response to heat and oxidative stress. We determined that a M. tuberculosis sigh mutant is more susceptible to oxidative stresses and that the inducible expression of the thioredoxin reductase/thioredoxin genes trxB2/trxC and a gene of unknown function, Rv2466c, is regulated by sigH via expression from promoters directly recognized by SigH. We ...
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Fingerprint Dive into the research topics of Mycobacterium tuberculosis ECF sigma factor sigC is required for lethality in mice and for the conditional expression of a defined gene set. Together they form a unique fingerprint. ...
Author Summary Positive auto-regulation of a transcriptional activator during cell differentiation or development often allows the rapid and robust deployment of cell- and stage-specific genes and the routing of the differentiating cell down a specific path. Positive auto-regulation however, raises the potential for inappropriate activity of the transcription factor. Here we unravel the role of a previously characterized anti-sigma factor, CsfB, in a negative feedback loop that prevents ectopic expression of the sporulation-specific sigma factor σG of Bacillus subtilis. σG is activated in the forespore, one of the two chambers of the developing cell, at an intermediate stage in spore development. Once active, a positive feedback loop allows the rapid accumulation of σG. Synthesis of both σG and CsfB is under the control of the early forespore regulator σF, and CsfB may help prevent the premature activity of σG in the forespore. However, CsfB is also produced under σG control in non-sporulating
Sigma factors [1] are bacterial transcription initiation factors that promote the attachment of the core RNA polymerase to specific initiation sites and are then released. They alter the specificity of promoter recognition. Most bacteria express a multiplicity of sigma factors. With regards to sequence similarity, sigma factors can be grouped into two classes: the sigma-54 and sigma-70 families. The sigma-70 family includes, in addition to the primary sigma factor, a wide variety of sigma factors. It also includes a divergent subfamily [2] that regulates gene encoding for proteins with extracytoplasmic function. The proteins that are currently known to belong to this sigma factor subfamily, known as ECF, are: ...
RNA polymerase sigma factor RpoD; Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. This sigma factor is the primary sigma factor during exponential ...
Reference gene for normalisation - for different growth rates - posted in PCR, RT-PCR and Real-Time PCR: Hello I am just starting RT-qPCR to study the activity of the promoter of a gene present on a recombinant plasmid in E. coli. This is known to be a stationary-phase promoter. Apart from this, I would also analyse the expression of rpoS - the stationary phase sigma factor and rpoD - the primary sigma factor, for comparison. Samples would be taken from different steady states from...
The anti-anti-sigma factor BldG has a pleiotropic function in Streptomyces coelicolor A3(2), regulating both morphological and physiological differentiation. Together with the anti-sigma factor UshX, it participates in a partner-switching activation of the sigma factor σH, which has a dual role in the osmotic stress response and morphological differentiation in S. coelicolor A3(2). In addition to UshX, BldG also interacts with the anti-sigma factor ApgA, although no target sigma factor has yet been identified. However, neither UshX nor ApgA phosphorylates BldG. This phosphorylation is provided by the anti-sigma factor RsfA, which is specific for the late developmental sigma factor σF. However, BldG is phosphorylated in the rsfA mutant, suggesting that some other anti-sigma factors containing HATPase_c kinase domain are capable to phosphorylate BldG in vivo. Bacterial two-hybrid system (BACTH) was therefore used to investigate the interactions of all suitable anti-sigma factors of S. coelicolor ...
All bacteria have sigma factors, proteins that initiate transcription by binding to RNA polymerase. Sigma factors can regulate how bacteria respond to extracellular stresses, which can be diverse - from nutritional cues, to changes in oxidative state or temperature. For some sigma factors, the regulation is imposed by a group of proteins called zinc-binding anti-sigma factors (ZAS). In this system, the ZAS protein rather than the sigma factor responds to stress. ZAS protein and sigma factor are bound in a tight complex in the resting state. When a cue is received, the ZAS protein releases the sigma factor, enabling it to switch on genes that will neutralize the stress.. Different bacteria use ZAS proteins to respond to different stresses. In Mycobacterium tuberculosis, a ZAS-sigma factor complex is required for pathogenesis. In Bacillus subtilis, the system is used to protect the bacteria against antibiotics. The ZAS-sigma system is important in many bacteria for dealing with oxidative stress, ...
The σE-dependent extracytoplasmic stress response.σE is held at the membrane by the antisigma factor RseA. RseB binds to the periplasmic domain of RseA and pr
sigma factor definition: nounA protein component of bacterial RNA polymerase that recognizes the correct site on DNA for initiating transcription of a gene and that is usually released soon after transcription begins....
Although Escherichia coli is generally considered to be predominantly a commensal of the gastrointestinal tract, a number of recent studies suggest that it is also capable of long-term survival and growth in environments outside the host. As the extraintestinal physical and chemical conditions are often different from those within the host, it is possible that distinct genetic adaptations may be required to enable this transition. Several studies have shown a trade-off between growth and stress resistance in nutrient-poor environments, with lesions in the rpoS locus, which encodes the stress sigma factor RpoS (σS). In this study, we investigated a unique collection of long-term soil-persistent E. coli isolates to determine whether the RpoS-controlled general stress response is altered during adaptation to a nutrient-poor extraintestinal environment. The sequence of the rpoS locus was found to be highly conserved in these isolates, and no nonsense or frameshift mutations were detected. Known ...
InterPro provides functional analysis of proteins by classifying them into families and predicting domains and important sites. We combine protein signatures from a number of member databases into a single searchable resource, capitalising on their individual strengths to produce a powerful integrated database and diagnostic tool.
RECOMMENDED: If you have Windows errors then we strongly recommend that you download and run this (Windows) Repair Tool.. Topic Error Rate Calculation. given that the opportunity for error varies daily by the dollar amount presented and the. What is Six Sigma? Six Sigma.. The statistical representation of Six Sigma describes quantitatively how a process is performing. To achieve Six Sigma, a process must not produce more than 3.4.. An introduction to delta sigma converters without much theory and mathematics. Discover the Differences between 3 Sigma vs. 6 Sigma - Three Sigma vs. Six Sigma. the practical goal of Six Sigma programs is to continually improve the rate of. In cases where too much error is not assignable.. Shot Online Error Shot.exe As suggested elsewhere online, Ive tried every permutation of running Origin and ME. Screen Shot 2012-06-23 at 12.49.18 AM.jpg. Repeat these steps until only explorer.exe and task mgr.exe are open. In brief, the lipoaspirate were incubated in RPMI 1640 ...
Negative regulation of germination-arrest factor production in Pseudomonas fluorescens WH6 by a putative extracytoplasmic function sigma factor ...
The repertoire of genes expressed under more than a hundred different conditions, which mimic the natural, laboratory and industrial environments of B. subtilis, was determined [link to Nicolas et al in Science, Link to www.basysbio.eu/bsubtranscriptome/seb]. Through this study of unprecedented scope, we have been able to infer how the B. subtilis transcription network is regulated during adaptation to nutritional changes and physical and chemical stresses [Link to www.basysbio.eu/bsubtranscriptome]. The study identified 512 new potential genes and abundant antisense RNAs. It also identified over 3000 promoters which were classified according to their activity profiles by a newly developed statistical approach. Groups of genes with similar profiles were associated with various types of the gene expression machinery (RNA polymerase sigma factors), allowing for the first time to quantify the contribution of the sigma factors in the variation of gene expression. We discovered that switching between ...
In Escherichia coli, the stationary phase alternative sigma factor σs controls the expression of genes involved cell survival in response to cessation of growth (stationary phase) and provides cross-protection to various stresses. Levels of σs increase dramatically at the onset of stationary phase and are regulated at the transcriptional, post-transcriptional and post-translational level, making this one of the most complex regulatory systems in bacteria. The basic mechanisms for the control of translation and σs proteolysis have been understood. However, studies on the transcriptional control in E. coli lag behind and are controversial. The cAMP-CRP complex and the two component BarA/UvrY system have been implicated and, ppGpp and polyphosphate appear to have a signalling role. σs has also been reported to be a general stress regulator in the fluorescent pseudomonads (Pseudomonas aeruginosa, P. fluorescens and P. putida) and recent studies on σs regulation highlight that transcriptional ...
RNA polymerase sigma 70 antibody [2G10] for ELISA, IP, WB, Functional Assay. Anti-RNA polymerase sigma 70 mAb (GTX12088) is tested in Bacteria samples. 100% Ab-Assurance.
The general stress response (GSR) represents an important trait to survive in the environment by leading to multiple stress resistance. In alphaproteobacteria, the GSR is under the transcriptional control of the alternative sigma factor EcfG. Here we performed transcriptome analyses to investigate the genes controlled by EcfG of Sphingomonas melonis Fr1 and the plasticity of this regulation under stress conditions. We found that EcfG regulates genes for proteins that are typically associated with stress responses. Moreover, EcfG controls regulatory proteins, which likely fine-tune the GSR. Among these, we identified a novel negative GSR feedback regulator, termed NepR2, on the basis of gene reporter assays, phenotypic analyses, and biochemical assays. Transcriptional profiling of signaling components upstream of EcfG under complex stress conditions showed an overall congruence with EcfG-regulated genes. Interestingly however, we found that the GSR is transcriptionally linked to the regulation of
This is a eight-day Lean Six Sigma Greenbelt training at HBO level. How and with what success could you improve your processes? What makes it so successful? And how does the method work in practice? In this training you learn the main methods and techniques of the Lean Six Sigma methodology. During this intensive training you will be trained to become Six Sigma Green Belt.. Lean Six Sigma Green Belt training, good for the development of your organisation and your career!. The certificate Lean Six Sigma Green Belt is recognized worldwide. Many companies use the techniques of Lean and Six Sigma. These companies improve their lead times and the quality of their products. After attending the course you can make a valuable contribution to this process. There is so much demand for experts in the field of Lean Six Sigma. A good addition to your CV so!. ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
Bacteria necessitate multiple signal transduction systems to sense the ever-changing environments and mediate the cellular response accordingly. The major bacterial signal transduction systems are one-component system (1CS), two-component system (2CS) and extracytoplasmic function (ECF) σ factor. Compared to 1CSs and 2CSs, ECF σ factors have only been identified much later and therefore the knowledge about their molecular mechanisms and physiological roles is less profound. This thesis mainly focuses on the study of ECF σ factors from the bacterial phyla, Planctomycetes and Actinobacteria., In the first two parts of this study, ECF σ factors from eight planctomycetal genomes and 119 actinobacterial genomes were classified and analyzed in depth. This led to the identification of eight novel ECF groups consisting of 202 protein members from Planctomycetes and 18 novel ECF groups consisting of 427 protein members from Actinobacteria, respectively. Many of these novel ECF groups were found to ...
Sigma legt mit seiner über 50 Jahren währende Geschichte großen Wert auf das Gesamtpaket ihrer Produkte. So wählten sie nicht ohne Grund den Namen Sigma für ihr Unternehmen.. Der griechische Buchstabe S steht für die Gesamtsumme und ist Sinnbild für die Unternehmensphilosophie von Sigma.. Sigma legt die Schwerpunkte auf Entwicklung und Produktion, sodass Sigma Objektive immer auf dem neuesten Stand der Technik sind.. Sigma achtet ganz besonders bei der Produktion der Objektive darauf, dass weder umweltbelastende Stoffe wie Blei oder Arsen verwendet werden, noch das mit den Ressourcen verschwenderisch umgegangen wird.. Grundlegende Eckpunkte der Philosophie sind:. ...
Paul Keller is President and Chief Operating Officer of Quality America, a Six Sigma consulting, training, and publishing firm. Description: Six Sigma is among the most effective process methods used today-and its also among the most baffling topics to those new to the subject. The good news is Six Sigma DeMYSTiFieD, Second Edition, explains it all in a language youll understand. This easy-to-understand reference teaches the methods of Six Sigma, explains their applications, and tests expertise-without confusing statistics and formulas. In no time, youll develop the skills you need to solve problems, anticipate customer needs, and meet the demands of the most challenging markets. Filled with practical hands-on advice and essential organizational tips, Six Sigma DeMYSTiFieD provides a complete blueprint for developing strategies, plotting growth, and performing at peak efficiency for maximum profits. This fast and easy guide offers: • Proven techniques for building a solid Six Sigma ...
Redox regulated effector systems that counteract oxidative stress are essential for all forms of life. Here, we uncover a new paradigm for sensing oxidative stress centred on the hydrophobic core of a sensor protein. RsrA is an archetypal zinc-binding anti-sigma factor that responds to disulfide stress in the cytoplasm of Actinobacteria. We show that RsrA utilizes its hydrophobic core to bind the sigma factor σR preventing its association with RNA polymerase, and that zinc plays a central role in maintaining this high-affinity complex. Oxidation of RsrA is limited by the rate of zinc release, which weakens the RsrA-σR complex by accelerating its dissociation. The subsequent trigger disulfide, formed between specific combinations of RsrAs three zinc-binding cysteines, precipitates structural collapse to a compact state where all σR-binding residues are sequestered back into its hydrophobic core, releasing σR to activate transcription of anti-oxidant genes.
Binnie C, Lampe M, Losick R (1986) Gene encoding the sigma 37 species of RNA polymerase sigma factor from Bacillus subtilis. Proc Natl Acad Sci U S A 83:5943-7.[PMID:3016731 ...
The stressosome complex regulates downstream effectors in response to environmental signals. In Bacillus subtilis, it activates the alternative sigma factor σ(B), leading to the upregulation of the general stress regulon. Herein, we characterize a stressosome-regulated biochemical pathway in Moorell …
Get Sigma 14-24mm f/2.8 DG HSM Art at B&H Photo.. Confirming conclusions about lens performance is best done by shooting numerous scenes and seeing that all is in accord. The less than satisfying performance seen in Across the Canyon View of Checkerboard Mesa at 22mm is here evaluated at 23mm in a more complex 3D scene, to rule out field curvature as an explanation for the disappointing results.. In my review of the Sigma 14-24mm f/2.8 DG HSM Art:. Sigma 14-24mm f/2.8 DG HSM Art Aperture Series @ 23mm: Sandy Wash in Side Canyon, Zion. Includes up to full resolution images from f/2.8 through f/11 plus a 3-frame focus stack at f/9.. It is important when testing a zoom to test it across the zoom range, and also with near focus and far focus. I am not nearly so happy with performance at 22mm as at 14mm.. This series and others are important to understanding how to get the best out of the Sigma 14-24mm f/2.8 DG HSM Art, just as my review coverage of the Sigma 12-24mm f/4 DG HSM Art was and is. A lens ...
Non-linear sigma models with extended supersymmetry have constrained target space geometries, and can serve as effective tools for investigating and constructing new geometries. Analyzing the geometrical and topological properties of sigma models is necessary to understand the underlying structures of string theory.. The most general two-dimensional sigma model with manifest N=(2,2) supersymmetry can be parametrized by chiral, twisted chiral and semichiral superfields. In the research presented in this thesis, N=(4,4) (twisted) supersymmetry is constructed for a semichiral sigma model. It is found that the model can only have additional supersymmetry off-shell if the target space has a dimension larger than four. For four-dimensional target manifolds, supersymmetry can be introduced on-shell, leading to a hyperkähler manifold, or pseudo-supersymmetry can be imposed off-shell, implying a target space which is neutral hyperkähler.. Different sigma models and corresponding geometries can be ...
The PDB archive contains information about experimentally-determined structures of proteins, nucleic acids, and complex assemblies. As a member of the wwPDB, the RCSB PDB curates and annotates PDB data according to agreed upon standards. The RCSB PDB also provides a variety of tools and resources. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists.
Transcription initiation is a critical step in bacterial gene regulation and is often controlled by transcription regulators. The alternate sigma factor (sigma54) is one such regulator that facilitates activator-dependent ...
Yoshimine, M.; McLean, A.D.; Liu, B., Band strengths for electric dipole transitions from ab initio computation: LiO (X2«PI»-X2«PI», (A2«SIGMA»+-A2«SIGMA»+), (X2«PI»-A2«SIGMA»+); AlO (X2«SIGMA»+-X2«SIGMA»+), (A2«PI»-A2«PI»), (X2«SIGMA»+-A2«PI»), (B2«SIGMA»+-B2«SIGMA»+), (X2«SIGMA»+-B2«SIGMA»+), J. Chem. Phys., 1973, 58, 4412. [all data] Linton and Nicholls, 1969 ...
Sigma Phosphate Buffer Saline found in: SIGMA Phosphate buffered saline, powder, pH 7.4, SIGMA Phosphate buffered saline, pH 7.2 (25 °C), SIGMA Phosphate..
cansSAR 3D Structure of 5VT0_L | ESCHERICHIA COLI 6S RNA DERIVATIVE IN COMPLEX WITH ESCHERICHIA COLI RNA POLYMERASE SIGMA70-HOLOENZYME | 5VT0
The Bacillus cereus sensu lato group consists of six species (B. anthracis, B. cereus, B. mycoides, B. pseudomycoides, B. thuringiensis, and B. weihenstephanensis). While classical microbial taxonomy proposed these organisms as distinct species, newer molecular phylogenies and comparative genome sequencing suggests that these organisms should be classified as a single species (thus, we will refer to these organisms collectively as the Bc species-group). How do we account for the underlying similarity of these phenotypically diverse microbes? It has been established for some time that the most rapidly evolving and evolutionarily flexible portions of the bacterial genome are regulatory sequences and transcriptional networks. Other studies have suggested that the sigma factor gene family of these organisms has diverged and expanded significantly relative to their ancestors; sigma factors are those portions of the bacterial transcriptional apparatus that control RNA polymerase recognition for promoter
Background Sigma factors are proteins that regulate transcription in bacteria. Sigma factors can be activated in response to different environmental conditions. The rpoS (RNA polymerase, sigma S) gene encodes sigma-38 (σ38, or RpoS), a 37.8 kDa protein in Pseudomonas aeruginosa (P. aeruginosa) strains. RpoS is a central regulator of the general stress response and operates in both retroactive and proactive manners; not only does it allow the cell to survive environmental challenges; it also prepares the cell for subsequent stresses (cross-protection). Methods The significance of RpoS for stress resistance and protein expression in stationary-phase P. aeruginosa cells was assessed. The goal of the current study was to characterize RpoS of P. aeruginosa PAO1 using bioinformatics tools. Results The results showed that RpoS is an unstable protein that belongs to the sigma-70 factor family. Secondary structure analysis predicted that random coil is the predominant structure followed by extended alpha helix.
The intestinal pathogen V. cholerae has a complicated life cycle that includes growth within an aquatic environment, oral ingestion by human hosts, passage through the low pH environment of the stomach, colonization within the small intestine, and subsequent dissemination in the cholera stool back into its aquatic niche. The study of environmentally induced gene regulation of V. cholerae has primarily focused on the production and regulation of virulence factors within the host environment (16, 20). Recently, however, the role of the stationary-phase sigma factor RpoS in regulation of genes required for surviving a variety of environmental stresses was demonstrated (22). In addition, the V. cholerae RpoS was found to positively regulate expression of at least 25 different genes upon entry into stationary phase (22). Similar but diverse roles for RpoS in response to environmental stresses have been demonstrated in a variety of bacterial species, including E. coli, S. flexneri, Y. enterocolitica, ...
The soil living, Gram-positive bacterium Bacillus subtilis is frequently exposed to a wide variety of stress and starvation conditions in its natural environment. In order to survive under these environmental and energy stresses, the bacterium acquired a general stress response mechanism mediated by the alternative sigma factor, SigB. A wide-variety of stress conditions such as environmental stress conditions like ethanol stress, heat stress, oxidative stress, osmotic stress or limitation of glucose, oxygen, phosphate etc.; and low temperature growth induce this SigB-dependent general stress response. Though much is known about the mechanisms of activation of this general stress response, the conditions that induce the SigB regulon and its general functions, the definition of the structure of the SigB regulon is not completely clear. The SigB-dependent general stress regulon has previously been characterized by proteomic approaches as well as DNA-array based expression studies. Genome-wide ...
Sigma factors and the alarmone ppGpp control the allocation of RNA polymerase to promoters under stressful conditions. Both ppGpp and the sigma factor σS (RpoS) are potentially subject to variability across the species Escherichia coli. To find out the extent of strain variation we measured the level of RpoS and ppGpp using 31 E. coli strains from the ECOR collection and one reference K-12 strain. Nine ECORs had highly deleterious mutations in rpoS, 12 had RpoS protein up to 7-fold above that of the reference strain MG1655 and the remainder had comparable or lower levels. Strain variation was also evident in ppGpp accumulation under carbon starvation and spoT mutations were present in several low-ppGpp strains. Three relationships between RpoS and ppGpp levels were found: isolates with zero RpoS but various ppGpp levels, strains where RpoS levels were proportional to ppGpp and a third unexpected class in which RpoS was present but not proportional to ppGpp concentration. High-RpoS and high-ppGpp
The Pm promoter of the TOL plasmid of Pseudomonas putida is expressed at high level along the growth curve. This transcription is dependent on the positive regulator XylS activated by 3-methylbenzoate. The sigma factor sigma 38 is required for expression in early stationary phase and thereafter. To …
FIG. 4. Role of RssB-ClpXP and putative signal input in the σS recognition and degradation pathway. The response regulator RssB is an essential, specific, and direct σS recognition factor. RssB delivers σS to the ClpXP protease, where σS is unfolded and completely degraded whereas RssB is released. σS binding requires RssB phosphorylation, but it is unclear whether the catalytic cycle of RssB involves obligatory dephosphorylation during release and subsequent rephosphorylation. Stress signals may affect (i) the phosphorylation of RssB and therefore RssB-σS complex formation; (ii) the cellular level of RssB (which in growing cells is rate limiting for σS proteolysis); (iii) the synthesis of σS such that RssB becomes titrated on σS overproduction; (iv) σS association with RNA polymerase core enzyme, which protects against binding by RssB; and (v) the function of the ClpXP protease itself (see the text for details). However, the molecular details of the stress signal input pathways ...
In the version of central limit theorem for strictly stationary but weakly dependent (for instance $\alpha$-mixing with fast decaying mixing coefficient) random variables $X_1, X_2, \cdots$, the theorem in this Wikipedia page states (see also Billingsley 1995 Theorem 27.4):. Theorem. Suppose that $X_1, X_2, \cdots$ is stationary and $\alpha$-mixing with $\alpha_n = O(n^{−5})$ and that $\mathbb{E} X_n = 0$ and $\mathbb{E} X_n^{12} , \infty$. Denote $S_n = X_1 + \cdots + X_n$, then the limit $\sigma^2 = \lim_{n\to \infty} \mathbb{E} S_n^2/n$ exists, and if $\sigma \ne 0$ then $S_n/(\sigma \sqrt{n})$ converges in distribution to the standard Gaussian distribution $\mathcal{N}(0, 1)$.. Here $\alpha_n$ is the mixing coefficients defined as e.g. in this Wikipedia page.. My question is: Is there a proof for the necessity of $\sigma , 0$? What can we conclude (if possible) when $\sigma = 0$? In the wikipedia page, there is a little remark trying to explain the necessity of $\sigma , 0$ (note that ...
When prokaryotic organisms transcribe DNA into RNA it involves in many cases the binding of a sigma factor upstream of the transcription start site. This guides the RNA polymerase (RNAP) into position to facilitate the transcription process. Sigma factors also have important regulatory functions and many different factors acts to ensure differential regulation of different classes of genes under different conditions. In this exercise we will look at σ70 (or RpoD) which is the housekeeping sigma factor responsible for regulating most genes in the prokaryotic cell. It has two distinct binding sites -10 and -35 upstream of the transcription start site, often denoted by the consensus sequences: TATAAT and TTGACA. Since the hexamers rarely match the consensus, information theory is often used to describe the observed variation and to measure how well a given promoter fits a model. This measure is provided in bits of information. ...
The Bacillus subtilis σ W regulon is induced by different stresses that most probably affect integrity of the cell envelope. The activity of the extracytoplasmic function (ECF) sigma factor σ W is modulated by the transmembrane anti-sigma factor RsiW, which undergoes stress-induced degradation in a process known as regulated intramembrane proteolysis, finally resulting in the release of σ W and the transcription of σ W-controlled genes. Mutations in the ecsA gene, which encodes an ATP binding cassette (ABC) of an ABC transporter of unknown function, block site-2 proteolysis of RsiW by the intramembrane cleaving protease RasP (YluC). In addition, degradation of the cell division protein FtsL, which represents a second RasP substrate, is blocked in an ecsA-negative strain. The defect in σ W induction of an ecsA-knockout strain could be partly suppressed by overproducing RasP. A B. subtilis rasP-knockout strain displayed the same pleiotropic phenotype as an ecsA knockout, namely defects in processing
You might need to reconsider your definition of Sigma.. I take mine from the article The Nature of Six Sigma Quality by Mikel Harry, published by the Motorola University Press in the early 1990s (the specific copyright date varies depending on the date of printing.) By definition, an X Sigma process is one which, when centered halfway between the lower and upper specification limits (LSL & USL), the LSL is located at [mu - X*sigma] (where s is the process standard deviation), and the USL is located at [mu + X*sigma].. A 6 Sigma process is one where, IF the process were centered, the LSL is exactly at [mu - 6*sigma] and the USL is exactly at [mu + 6*sigma).. This is the definition given by Mikel Harry in his article. Its shown in Figure 8.. When the much debated 1.5*sigma shift occurs (here assuming a shift to the right for the sake of computation), the LSL & USL are no longer as described before, now they are at [mu - (X + 1.5)*sigma] & [mu + (X - 1.5)*sigma], respectively. For a 6 Sigma ...
Lean Six Sigma Black Belt is the creme de la creme of Lean Six Sigma. It is the end of the belt like structure that is Lean Six Sigma...
SWISS-MODEL Repository entry for P77994 (SIGA_THEMA), RNA polymerase sigma factor SigA. Thermotoga maritima (strain ATCC 43589 / MSB8 / DSM 3109 / JCM 10099)
OVERVIEW_[ ->As a Six Sigma team moves into the Analyze phase of a project, team members begin analyzing the information and data collected in the earlier phases. During the Analyze phase, Six Sigma teams identify possible sources of variation, underlying root causes, and areas for improvement. It is here where assumptions or hypotheses about a process, product, or service are made and validated using tests based on sample data. This course aims to familiarize you with some of the advanced hypothesis tests used in Six Sigma. You are taken through the key steps in testing hypotheses for proportions, variances, and analysis of variance (ANOVA), and their underlying assumptions, with the help of examples and case studies. You will also learn how to use goodness-of-fit test statistics and contingency tables for validating hypotheses about various aspects of the variables being analyzed. This course is aligned with the ASQ Certified Six Sigma Black Belt certification exam and is designed to assist ...
See my Sigma SLR lenses wishlist at B&H Photo.. This far distance series evaluates lens performance from f/1.4 through f/5.6 across the frame, giving an excellent look at just how good the Sigma 28mm f/1.4 DG HSM Art is.. Uniform sharpness is very challenging for a lens for far distance scenes like this, so that precise focus is critical. This series was focused perfectly so as to extract maximum performance across the field so this series represents an optimal performance with the Sigma 28mm f/1.4 DG HSM Art.. Sigma 28mm f/1.4 DG HSM Aperture Series: View of Peaks near Mt Whitney, Very Late Dusk (Nikon D850). Includes images up to full camera resolution from f/1.4 through f/5.6.. ...
The Sigma APO 300-800mm F5.6 EX IF HSM is one of several new products introduced at Photokina 2002 by Sigma Corporation of Japan (2-3-15, Iwado-Minami, Komae-shi, Tokyo, Japan). Sigma APO 300-800mm F5.6 EX IF HSM provides a constant F-number from 300mm telephoto to 800mm ultra-telephoto. This super-telephoto zoom lens has a horizontal angle of view of 6.9 at 300mm and 2.6 at 800mm. Its ability to zoom from a fixed position offers unparalleled versatility in composing an image. It incorporates two pieces of ELD (Extraordinary Low Dispersion) glass in the front for effective compensation of chromatic aberration. Since focusing and zooming do not change its overall length, this lens offers ease of handling and operation. The HSM ensures a quiet, high-speed AF function as well as full-time manual focusing capability for Sigma, Canon, Nikon mount lenses. A 46mm filter can be inserted near the rear of the lens, and a circular polarizing filter can be used. When this lens is used with the 1.4x EX or 2x EX Apo
A crossed beam investigation of the reactions of tricarbon molecules, C(3)(X(1)Sigma(+)(g)),with acetylene, C(2)H(2)(X(1)Sigma(+)(g)), ethylene, C(2)H(4)(X(1)A(g)), and benzene, C(6)H(6)(X(1)A(1g)) Article ...
b). However, the solution model of RseA121-216/RseB clearly shows that its envelope is more globular than either free RseB or the RseA169-196/RseB complex, thereby suggesting that the cleft in free RseB is occupied by a certain region of RseA. Since the minimum binding fragment (RseA169-196) was not clearly visualized in the RseA169-196/RseB complex and the empty cleft in free RseB was occupied in the complex of RseA121-216/RseB, it is thought that some other region of RseA was also involved in RseB binding and was visualized in the SAXS model of the RseA121-216/RseB complex. Taking these results together, it can be proposed that the unstructured free RseA becomes more structured and stabilized when it binds to RseB, and more than two separate regions of RseA are involved in RseB binding. Consistently with our notion, it has been proposed that the periplasmic domain of RseA would interact with RseB using two regions: residues near 169-186 and an undefined region (Cezairliyan & Sauer, 2007 ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
I will assume Sigma read this thread! ,,LEAF SHUTTER LENS!, come on sigma! The FP is useless for flash photography (and artificial light) without a mechanical shutter. Leaf shutter lens allow syncing flash at a higher speed than can focal plane. Normal territory of medium format. Time to compete with Hasselblad X1D! Sigma know how to make superb leaf shutter lens in the DP series. Make compact 28/75 mm f2.8 leaf shutter prime lens, just like your 45mm - but put a leaf shutter in that one too. Take the FP to the next level. Leaf shutter lens will attract a huge new number of people to the FP and L mount system for photography. ...
Microbiology Society journals contain high-quality research papers and topical review articles. We are a not-for-profit publisher and we support and invest in the microbiology community, to the benefit of everyone. This supports our principal goal to develop, expand and strengthen the networks available to our members so that they can generate new knowledge about microbes and ensure that it is shared with other communities.
Intracellular Signaling. To survive, bacteria must continuously monitor changes in nutrient status & adjust their physiology. During rapid growth, our lab strain grows predominantly as non-motile, chained cells. The decision to switch to a single-cell, motile mode occurs during the transition between rapid growth & stationary phase, which is regulated by increased expression & activity of an alternative sigma factor, SigD. We discovered that SigD levels & activity are controlled by cellular levels of the small intracellular molecules GTP & p(ppGpp). This work is significant because it provides evidence that graded levels of key intracellular signaling molecules regulate developmental decisions (and transcriptional programs). We hypothesize that intracellular levels of one or more small molecules is also responsible for coordinating DNA replication rates, protein synthesis, transcription, & cell growth/division with cellular nutrient status.. Q. A. Ababneh and J. K. Herman. CodY regulates SigD ...
com.sigma.fs3.argos.domain.gpc.GpcArticlesRev[id=com.sigma.fs3.argos.domain.gpc.GpcArticlesRevPK[ifcactivitat=ARE, ifccomptador=54664]], camposKey:0035-8711 2020-01-01 Amino acetaldehyde conformers: structure and spectroscopic properties18271833, com.sigma.fs3.argos.domain.gpc.GpcArticlesRev[id=com.sigma.fs3.argos.domain.gpc.GpcArticlesRevPK[ifcactivitat=ARE, ifccomptador=54675]], camposKey:0004-6361 2020-01-01 Reconstruction of water ice: the neglected process OH + OH =, H2O + O19, com.sigma.fs3.argos.domain.gpc.GpcArticlesRev[id=com.sigma.fs3.argos.domain.gpc.GpcArticlesRevPK[ifcactivitat=ARE, ifccomptador=57486]], camposKey:0004-637X 2020-01-01 Structure and Spectroscopic Properties of Hydrocalcium Isocyanide Isomers: Plausible Astronomical Ca-bearing Molecules00, com.sigma.fs3.argos.domain.gpc.GpcArticlesRev[id=com.sigma.fs3.argos.domain.gpc.GpcArticlesRevPK[ifcactivitat=ARE, ifccomptador=50466]], camposKey:2472-3452 2019-01-01 Formation of Protonated Glycine Isomers in the Interstellar ...
In 1983, Lambda Omega Sigma became the first Greek Fraternity at Pepperdine with the motto Through Service We Shine and in 1998 they became the Lambda Sigma Chapter of Psi Upsilon, and kept that focus on service. The chapter hosts a wildly successful philanthropy that not only includes the Greek community, but also attracts participation outside the fraternity and sorority world. During this years Psi U Think U Can Dance Philanthropy, the Lambda Sigma chapter not only sold nearly 500 tickets, but also raised over $18,000 for Conquer Paralysis Now, a non-profit started by the chapters first president, Sam Schmidt 86. Read the article in the JANUARY 29, 2020 Pepperdine Graphic ...
In addition, the Company is continuing with its strategic alternatives review process. Sigma Designs does not plan to hold a conference call in association with the information in this news release. The Company will provide an update on these actions when it determines that further disclosures are appropriate. Use of Non-GAAP Financial Information In addition to reporting financial results in accordance with generally accepted accounting principles (GAAP), Sigma reports non-GAAP financial measures, as Sigma believes that evaluating its ongoing operating results may be difficult if limited to reviewing only GAAP financial measures. Non-GAAP financial measures are not a substitute for financial information prepared in accordance with GAAP. Therefore, non-GAAP financial measures should not be considered in isolation, but should be considered together with the most directly comparable GAAP financial measures and the reconciliation of the non-GAAP financial measures to the most directly comparable ...
Sigma receptors, both Sigma‐1(S1R) and Sigma‐2 (S2R), are small molecule‐regulated, primarily endoplasmic reticulum (ER) membrane‐associated sites
FOUR SEVEN SIGMA™ is a modern, progressive goggle with design details that recall Salomons heritage of innovation. FOUR SEVEN SIGMA™ boasts a unique anatomical fit, wide field of vision, and a SIGMA™ lens that amplifies contrast, enabling the eye to read
FOUR SEVEN SIGMA™ is a modern, progressive goggle with design details that recall Salomons heritage of innovation. FOUR SEVEN SIGMA™ boasts a unique anatomical fit, wide field of vision, and a SIGMA™ lens that amplifies contrast, enabling the eye to read
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Functional profiling of the crosstalk among sigma factors in P. aeruginosa.The PseudoCAP annotation [55] was used to categorize the members of the direct (viole
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Sigma Life Science, the innovative biological products and services research business of Sigma-Aldrich® (Nasdaq: SIAL), today announced the release of OligoArchitectTM, an online primer and probe design tool. This freely available tool offers automated design of probes and primers for real-time qPCR assays, powered by the industry standard Beacon DesignerTM platform from PREMIER Biosoft, it complements Sigma Life Sciences comprehensive portfolio of oligonucleotide and qPCR products and customized oligonucleotide services...
Information about Novaquimica Sigma Pharma-Natures Plus products database; lists of Novaquimica Sigma Pharma-Natures Plus pharmaceutical drugs and health care production from Drugs-about.com
Kendricks example of modifying the analysis aposteriori is a good one and things are made worse if we adopt a 2 sigma standard for detection (and there are cosmology papers out there doing this, you know who you are :-), since it is the change in \chi^2 that is relevant, so a change of 4 may only be 0.5 sigma if you start from 4 sigma, but is in fact 2 sigma if you start from 0. This can either be done intentionally and aposteriori, ie one can imagine someone doing multiple analyses using different data subsets or weights or error estimation methods etc and choosing the one with highest S/N, but may also happen unintentionally and seemingly not aposteriori, ie one group does their analysis and finds nothing, but another group with different cuts etc finds a 2 sigma deviation and claims a detection, without realizing that if twenty groups did an analysis of a random subset of the data with no signal one among them will find a 2 sigma detection. Finally, there is the issue of absence of any ...
The higher the value, the more capable the process of meeting specifications. A value of 2 or higher is required to achieve Six Sigma capability which is defined as the process mean not closer than six standard deviations from the nearest specification limit.. All of the indices assume a normally distributed process quality characteristic with the parameters specified by the process mean and sigma. The process sigma is either the short-term or long-term sigma estimate.. Indices computed using the short-term sigma estimate are called Cp indices (Cp, Cpl, Cpu, Cpk, Cpm). While those using long-term sigma estimate are called Pp indices (Pp, Ppl, Ppu, Ppk, Ppm). If the Cp indices are much smaller than the Pp indices, it indicates that there are improvements you could make by eliminating shifts and drifts in the process mean.. ...
To date, all of Art lenses feature Sigmas HSM (Hypersonic Motor) driving AF and this statement covers the 85 f/1.4 Art Lens. This lens predecessor also had an HSM AF system, but according to Sigmas press release, A re-engineered AF system brings 1.3X the torque of its predecessor, while other features such as a full-time manual focus override have been added, which can be controlled when the focus ring is rotated, even during continuous AF. Without doing a side-by-side comparison, I cant tell if that torque difference is noticeable, but autofocus happens reasonably quickly with short distance changes. Focus at 3 (1m) and then at 20 (m) and you will not likely consider the word fast for a descriptor as you wait for the subject to come into focus. Especially in lower light levels, some minor autofocus distance adjustments are often made after the initial focus acquisition, increasing the overall AF lock times of even shorter distance adjustments. While this lens may not be the ...
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Lean Six Sigma Master Black Belt , avec des réalisations exceptionnelles dans le déploiement du Lean Six Sigma avec une multitude dindustries manufacturières et dans le secteur du service, avec un fort accent sur le développement dune culture damélioration continue visant la satisfaction client, la réduction des couts, une amélioration de la qualité et des délais , ce qui se traduit en une amélioration de lefficacité opérationnelle. ...
There were two highlights of IBC 2019 for me. The Sigma Fp, and the Z-CAM range. From the ground-up the Sigma Fp seems to be aimed at us, at artists. A small and incredibly light camera that hits the big full frame notes, some of the niche features like the digital directors viewfinder would be ...
Pen/Strep from Sigma unit confusion - posted in Tissue and Cell Culture: Dear all, I would like to ask about unit for Pen/Strep preparation from Sigma (P0781), 100 mL. On the label, the concentration is 10000 unit/10 mg/mL Pen/Strep. The 10000 unit of penicillin referred to the amount of penicillin present in 100 mL or the concentration (10000 unit/mL). Anyone can help me on this?
In this talk I will discuss geometric generalizations of Euclidean resolvent estimates, such as estimates for the resolvent of the Laplacian of an asymptotically conic metric plus a decaying potential, or of a Fourier transformed version of the Kerr wave operator, in a Fredholm framework that focuses on capturing the outgoing asymptotics of the resolvent applied to a Schwartz function (outgoing waves); this is different from even the usual treatment of the Euclidean problem. More precisely, the setting is that of perturbations \(P(\sigma)\) of the spectral family of the Laplacian \(\Delta_g-\sigma^2\) on asymptotically conic spaces \((X,g)\) of dimension at least \(3\) (with the asymptotic behavior at the `large end of the cone), and the main results are the limiting absorption principle, as well as uniform estimates for \(P(\sigma)^{-1}\) as \(\sigma\to 0\), on function spaces between which \(P(\sigma)\) is Fredholm even for real \(\sigma\neq 0\) and which correspond to finite regularity ...
In this talk I will discuss geometric generalizations of Euclidean resolvent estimates, such as estimates for the resolvent of the Laplacian of an asymptotically conic metric plus a decaying potential, or of a Fourier transformed version of the Kerr wave operator, in a Fredholm framework that focuses on capturing the outgoing asymptotics of the resolvent applied to a Schwartz function (outgoing waves); this is different from even the usual treatment of the Euclidean problem. More precisely, the setting is that of perturbations \(P(\sigma)\) of the spectral family of the Laplacian \(\Delta_g-\sigma^2\) on asymptotically conic spaces \((X,g)\) of dimension at least \(3\) (with the asymptotic behavior at the `large end of the cone), and the main results are the limiting absorption principle, as well as uniform estimates for \(P(\sigma)^{-1}\) as \(\sigma\to 0\), on function spaces between which \(P(\sigma)\) is Fredholm even for real \(\sigma\neq 0\) and which correspond to finite regularity ...
Group 1 sigma factors are critical for cell viability. Group 2, similar in structure to Group 1, is not essential for cell ... As noted above in RNA Polymerase and Sigma Factors, the beta clamp proteins within the RNAP complex have a higher initial ... Thus the gene is not effectively repressed.Synechocystis possesses the 70S sigma factor (σ70), which can be divided into three ... RNA polymerase (RNAP) and sigma factors are necessary proteins for transcription of DNA into messenger RNA (mRNA). Eubacterial ...
The gene rpoN (RNA polymerase, nitrogen-limitation N) encodes the sigma factor sigma-54 (σ54, sigma N, or RpoN), a protein in ... RpoN antagonizes RpoS sigma factors. Originally identified as a regulator of genes involved in nitrogen metabolism and ... Buck M, Cannon W (July 1992). "Specific binding of the transcription factor sigma-54 to promoter DNA". Nature. 358 (6385): 422- ... Gruber TM, Gross CA (2003). "Multiple sigma subunits and the partitioning of bacterial transcription space". Annual Review of ...
The origin of the Gen-Factor was revealed: Sigma. The Gen-Factor was the source of superhuman powers for many characters in the ... 35 Sigma #2 WildC.A.T.s #29 Deathblow #27 Gen¹³ #11 Backlash #20 Wetworks #17 Stormwatch #36 WildC.A.T.s #30 Sigma #3 Finale ... On Earth, Damocles' opponent from his homeworld had been reborn as the superhero Sigma. Damocles was assisted in his quest by ... Fire From Heaven #½ Prelude Sword Of Damocles #1 Sigma #1 Deathblow #26 Chapters Fire From Heaven #1 Backlash #19 Gen¹³ #10 ...
A sigma (σ) factor binds to the core, forming the holoenzyme. After transcription starts, the factor can unbind and let the ... RNAP core associates with the transcription initiation factor sigma (σ) to form RNA polymerase holoenzyme. Sigma reduces the ... the functions of the bacterial general transcription factor sigma are performed by multiple general transcription factors that ... There are multiple interchangeable sigma factors, each of which recognizes a distinct set of promoters. For example, in E. coli ...
The gene rpoE (RNA polymerase, extracytoplasmic E) encodes the sigma factor sigma-24 (σ24, sigma E, or RpoE), a protein in ... the gene encoding the second heat-shock sigma factor, sigma E, in Escherichia coli". The EMBO Journal. 14 (5): 1032-42. doi: ... De Las Peñas, A; Connolly, L; Gross, CA (Nov 1997). "SigmaE is an essential sigma factor in Escherichia coli". Journal of ... De Las Peñas, A; Connolly, L; Gross, CA (Nov 1997). "SigmaE is an essential sigma factor in Escherichia coli". Journal of ...
... encodes the sigma factor sigma-38 (σ38, or RpoS), a 37.8 kD protein in Escherichia coli. Sigma factors are proteins that ... Brown L, Elliott T (July 1996). "Efficient translation of the RpoS sigma factor in Salmonella typhimurium requires host factor ... Sigma factors can be activated in response to different environmental conditions. rpoS is transcribed in late exponential phase ... RpoS proteolysis forms another level of the sigma factor's regulation. Degradation occurs via ClpXP, a barrel-shaped protease ...
... sigma. RNA polymerase core enzyme binds to the bacterial general transcription factor sigma to form RNA polymerase holoenzyme ... the functions of the bacterial general transcription factor sigma are performed by multiple general transcription factors that ... "Holoenzyme switching and stochastic release of sigma factors from RNA polymerase in vivo". Molecular Cell. 20 (3): 357-66. doi: ... 8-Hydroxyquinoline info from SIGMA-ALDRICH. Retrieved Feb 2012. *^ Saxonov S, Berg P, Brutlag DL (January 2006). "A genome-wide ...
... sigma } the factor in the MSE remains approximately 2. Choosing a suitable value for τ {\displaystyle \tau } is a major ... The estimator of also reaches an MSE which is a constant factor times σ 2 N {\displaystyle {\frac {\sigma ^{2}}{N}}} . In this ... sigma ^{2}}{N}}} assuming a white Gaussian noise w n ∼ N ( 0 , σ 2 ) {\displaystyle w_{n}\sim {\mathcal {N}}(0,\sigma ^{2})} . ... sigma }}\int \limits _{x}^{\infty }e^{-w^{2}/2\sigma ^{2}}\,dw} Here τ {\displaystyle \tau } is a parameter leveraging our ...
ArcZ positively stimulates expression of RpoS stationary phase sigma factor. In plant pathogen Erwinia amylovora ArcZ was shown ...
This RNA polymerase appears to operate without a sigma factor/subunit. The purified Φ6 RdRP displays processive elongation in ...
In bacteria The promoter is recognized by RNA polymerase and an associated sigma factor, which in turn are often brought to the ... RNA polymerase holoenzymes containing other sigma factors recognize different core promoter sequences. <-- upstream downstream ... An inactive enhancer may be bound by an inactive transcription factor. Phosphorylation of the transcription factor may activate ... Several cell function specific transcription factors (there are about 1,600 transcription factors in a human cell) generally ...
"Regulation of Escherichia coli starvation sigma factor (sigma s) by ClpXP protease". Journal of Bacteriology. 178 (2): 470-476 ... Regulation of Escherichia coli starvation sigma factor (s) by ClpXP protease. Journal of Bacteriology 178: 470-476. Schultz, J ... and that this sigma factor thereby controlled development of the general stress response. Hunger stress was found to trigger ... "The putative sigma factor KatF has a central role in development of starvation-mediated general resistance in Escherichia coli ...
In bacteria, the sigma factor recognizes and binds to the promoter sequence. In eukaryotes, the transcription factors perform ... General transcription factors (GTFs) or basal transcription factors are protein transcription factors that have been shown to ... TFIIF (two subunits, RAP30 and RAP74, showing some similarity to bacterial sigma factors) and Pol II enter the complex together ... Chromatin structure-oriented factors are more complex than for initiation control. Often the chromatin-altering factor becomes ...
"Identification and characterization of the gene encoding the Acidobacterium capsulatum major sigma factor". Gene. 376 (1): 144- ...
Campagne S, Damberger FF, Kaczmarczyk A, Francez-Charlot A, Allain FH, Vorholt JA (2012). "Structural basis for sigma factor ...
"A DNA damage response in Escherichia coli involving the alternative sigma factor, RpoS". Proceedings of the National Academy of ...
In bacteria, there is one general RNA transcription factor known as a sigma factor. RNA polymerase core enzyme binds to the ... the functions of the bacterial general transcription factor sigma are performed by multiple general transcription factors that ... However, later data showed that upon and following promoter clearance, the sigma factor is released according to a stochastic ... In bacteria, it was historically thought that the sigma factor is definitely released after promoter clearance occurs. This ...
The activity of this sigma factor peaks at the start of the stationary phase. Autolysins are naturally produced by ... and lytF genes together leads to flagellar motility and is controlled by the activity of the chemotaxis sigma factor, σD. ...
Bautz's most important discovery is that of sigma factor, the first known transcription factor. He developed methods for the ... Burgess RR, Travers AA, Dunn JJ, Bautz EK: Factor stimulating transcription by RNA polymerase. Nature 1969, 221(5175):43-46). ...
Ms1 does not require the presence of the main sigma factor for RNAP interaction. There is evidence that Ms1 RNA may function ...
This protein is an anti-sigma factor which has been named "Audrey Stevens' Inhibitor". In 1998, Audrey Stevens Niyogi was ... Orsini (1993). "The asiA gene of bacteriophage T4 codes for the anti-sigma 70 protein". Journal of Bacteriology. 175 (1): 85-93 ...
"Regulation of toxin synthesis in Clostridium difficile by an alternative RNA polymerase sigma factor". Proceedings of the ... With this knowledge, Toxin B has been identified as the major virulence factor that causes the opening of tight junctions of ... With better understanding of the toxin, researchers were able to state that TcdB is the major virulence factor that causes CDI ... Hence, this leads to tumor necrosis factor α (TNF α) and proinflammatory interleukins being established as the major causative ...
In bacteria, the USP genes can be regulated by sigma factors within RNA polymerases. This includes sigma factor σ70 which ...
A 1-sigma interval therefore represents a factor of less than 2 in luminosity. This seems to indicate that all type Ia ... A more accurate value of the limit than that given by this simple model requires adjusting for various factors, including ...
Losick's research interests include RNA polymerase, sigma factors, regulation of gene transcription, and bacterial development ...
cspA protein binds Hfq, which upregulates production of sigma factors which mediate a stress response. Hfq binding sRNA ROSE ...
"A sigma factor that modifies the circadian expression of a subset of genes in cyanobacteria". EMBO J. 15 (10): 2488-95. doi: ...
"Mycobacterium tuberculosis virulence-regulator PhoP interacts with alternative sigma factor SigE during acid-stress response". ...
... and gene expression of all sigma factors of RNA polymerase in a cyanobacterium". J. Mol. Biol. 325 (5): 857-872. doi:10.1016/ ... Imamura S; Hanaoka M; Tanaka K (2008). "The plant‐specific TFIIB related protein, PBRP, is a general transcription factor for ...
This element interrupts a gene for the sigma factor σK and is excised during sporulation. The toxin-antitoxin system contained ...
transcription factor activity, sequence-specific DNA binding. • RNA polymerase II regulatory region sequence-specific DNA ... The homeobox genes encode a highly conserved family of transcription factors that play an important role in morphogenesis in ... "The thyroid transcription factor-1 gene is a candidate target for regulation by Hox proteins". EMBO J. 13 (14): 3339-47. PMC ...
The conversion factor between RPM and g depends on the radius of the centrifuge rotor. The particles' settling velocity in ... "Sigma-Aldrich. Retrieved 10 May 2016.. *^ Article on "Centrifugation" retrieved on 15 October 2013 from http://www.lenntech.com ...
... in addition to many extracytoplasmic function sigma factors, providing the organism with the ability to respond to a wide range ... "An essential transcription factor, SciP, enhances robustness of Caulobacter cell cycle regulation". Proceedings of the ...
displaystyle z={\frac {U-m_{U}}{\sigma _{U}}},\,}. where mU and σU are the mean and standard deviation of U, is approximately a ... displaystyle \sigma _{U}={\sqrt {n_{1}n_{2}(n_{1}+n_{2}+1) \over 12}}.\,}. The formula for the standard deviation is more ... displaystyle \sigma _{\text{corr}}={\sqrt {{n_{1}n_{2} \over 12}\left((n+1)-\sum _{i=1}^{k}{{t_{i}}^{3}-t_{i} \over n(n-1)}\ ...
... and the sigma factor subunits of RNA polymerase. Endospores of the bacterium Bacillus anthracis were used in the 2001 anthrax ... The heat resistance of endospores is due to a variety of factors: *Calcium dipicolinate, abundant within the endospore, may ... These studies have contributed much to our understanding of the regulation of gene expression, transcription factors, ...
Conversion factor electric charge q. C. Fr (cm3/2⋅g1/2⋅s−1). q. G. q. SI. =. 1. 4. π. ϵ. 0. =. 2.998. ×. 10. 9. Fr. 1. C. {\ ... displaystyle \left(\sigma ^{\text{G}},S^{\text{G}},C^{\text{G}}\right)}. 1. 4. π. ϵ. 0. (. σ. SI. ,. S. SI. ,. C. SI. ). {\ ... displaystyle \left(\sigma ^{\text{SI}},S^{\text{SI}},C^{\text{SI}}\right)}. 4. π. ϵ. 0. (. σ. G. ,. S. G. ,. C. G. ). {\ ... The numerical conversion factors can be derived from the symbolic conversion factors by dimensional analysis. For example, the ...
Sigma-Aldrich UK (pharmaceuticals) are off the B3092 on Brickfield Business Park in Gillingham, next to the River Stour and ... Both of these factors also cause it to experience the highest levels of snowfall and the lowest levels of sunshine. Exposed ...
In mechanical engineering, chi is used as a symbol for the reduction factor of relevant buckling loads in the EN 1993, a ... Sigma. Ηη. Eta. Ττ. Tau. Θθ. Theta. Υυ. Upsilon. Ιι. Iota. Φφ. Phi. ...
displaystyle \sigma }. , then G. =. 2. Φ. (. σ. /. 2. ). −. 1. {\displaystyle G=2\Phi (\sigma /{\sqrt {2}})-1}. where Φ. (. ). ... These factors are not assessed in income-based Gini. ... displaystyle G={\frac {2\Sigma _{i=1}^{n}\;iy_{i}}{n\Sigma _{i= ... displaystyle G=1-{\frac {\Sigma _{i=1}^{n}\;f(y_{i})(S_{i-1}+S_{i})}{S_{n}}}}. where. S. i. =. Σ. j. =. 1. i. f. (. y. j. ). y ... Sigma _{i=1}^{n}y_{i}}}\right)\right)}. Ini mungkin dimudahkan untuk:. G. =. 2. Σ. i. =. 1. n. i. y. i. n. Σ. i. =. 1. n. y. i ...
... sigma }}_{\alpha }\\\end{aligned}}}. or explicitly: A. =. A. 0. (. 1. 0. 0. 1. ). +. A. 1. (. 0. 1. 1. 0. ). +. A. 2. (. 0. −. ... where the Lorentz factor is defined by: γ. =. 1. 1. −. β. ⋅. β. ,. {\displaystyle \gamma ={\frac {1}{\sqrt {1-{\boldsymbol {\ ... sigma }}_{2}+A^{3}{\boldsymbol {\sigma }}_{3}\\&=A^{0}{\boldsymbol {\sigma }}_{0}+A^{i}{\boldsymbol {\sigma }}_{i}\\&=A^{\alpha ... is the Lorentz factor. This provides a useful relation between the differentials in coordinate time and proper time: d. t. =. γ ...
displaystyle M_{\Sigma },M_{N}\,\!}. *. Δ. M. =. M. Σ. −. M. n. u. c. {\displaystyle \Delta M=M_{\Sigma }-M_{\mathrm {nuc ... Spin factor: g. =. 2. J. +. 1. (. 2. s. a. +. 1. ). (. 2. s. b. +. 1. ). {\displaystyle g={\frac {2J+1}{(2s_{a}+1)(2s_{b}+1)}}} ... Wj = weighting factors corresponding to radiosensitivities of matter (dimensionless) ∑. j. W. j. =. 1. {\displaystyle \sum _{j} ... displaystyle M_{\Sigma }=Zm_{p}+Nm_{n}\,\!}. *. M. Σ. ,. M. N. {\ ...
ARID (1A, 1B, 2, 3A, 3B, 4A) • CAP • IFI (16, 35) • MLL (2, 3, T1) • MNDA • NFY (A, B, C) • Ro/Sigma ... Lüscher B (2001). "Function and regulation of the transcription factors of the Myc/Max/Mad network". Gene 277 (1-2): 1-14. PMID ... a widespread euchromatic program in the human genome partially independent of its role as a classical transcription factor". ...
giving an extra factor of 4. Thus, in total: U. =. 4. c. σ. T. 4. {\displaystyle U={\frac {4}{c}}\,\sigma \,T^{4}}. ... sigma T_{\odot }^{4}}{4\pi a_{0}^{2}}}\\\end{aligned}}}. T⊕ can then be found: T. ⊕. 4. =. R. ⊙. 2. T. ⊙. 4. 4. a. 0. 2. T. ⊕. ... displaystyle j^{\star }=\sigma T^{4}~,~~\sigma ={\frac {2\pi ^{5}k^{4}}{15c^{2}h^{3}}}={\frac {\pi ^{2}k^{4}}{60\hbar ^{3}c^{2 ... displaystyle j^{\star }=\varepsilon \sigma T^{4}.}. The radiant emittance j. ⋆. {\displaystyle j^{\star }}. has dimensions of ...
Affinity Chromatography»։ Sigma-Aldrich։ Արխիվացված օրիգինալից 2016-05-07-ին *↑ «HiTrap Heparin HP»։ GE Healthcare Life ... Evidence for an exosite determinant of factor Xa specificity in heparin-activated antithrombin»։ J. Biol. Chem. 276 (18): 14961 ... Chuang YJ, Swanson R. (2001)։ «Heparin enhances the specificity of antithrombin for thrombin and factor Xa independent of the ...
This is to be distinguished from factors, which are multiplied. Some authors call the first addend the augend.[5][6][7] In fact ... The sum of a series of related numbers can be expressed through capital sigma notation, which compactly denotes iteration. For ... This is correct since the next position has a weight that is higher by a factor equal to the radix. Carrying works the same way ...
Sigma Foveon. X3. Canon APS-C. Sony · Pentax · Sigma · Samsung. APS-C / Nikon DX. Canon APS-H. 35 mm Full-frame. / Nikon FX. ... Crop factor[14] 2.00. 1.74. 1.62. 1.52-1.54. 1.29. 1.0. 0.8. 0.78. 0.64 ... Sigma Foveon. X3. Canon APS-C. Sony · Pentax · Sigma · Samsung. APS-C / Nikon DX. Canon APS-H. 35 mm Full-frame. / Nikon FX. ... Crop factor[14] 2.00. 1.74. 1.62. 1.52-1.54. 1.29. 1.0. 0.8. 0.78. 0.64 ...
displaystyle {\begin{aligned}i&\leftarrow 1\\r_{1}&=r\\G_{1}&=(H^{H}H+\sigma ^{2}I_{N_{t}})^{-1}H^{H}\\k_{1}&=\arg \min \left ... sigma ^{2}I_{Nt})^{-1}H_{i}^{H}\\k_{i+1}&=\arg \min \left\,(G_{i+1})_{j}\right\,^{2}\\i&\leftarrow i+1\end{aligned}}}. ...
This unique action may be related to its ability to attenuate stress-induced anhedonia and corticotropin-releasing factor (CRF ... enhances hypothalamic BDNF expression in vivo by synergistic 5-HT2c receptor antagonism and sigma-1 receptor agonism". J. ... captodiamine is unique among antidepressant-like drugs in that it increases brain-derived neurotrophic factor (BDNF) levels in ...
"Delta Sigma Phi Rolla Alumni. Retrieved July 28, 2017.. *^ Alfred University (April 3, 2007). "St. Patrick". Archived from the ... The vehicle's cost, sales presentation, engineering design, acceleration, braking and racing performance all factor into its ... Kappa Epsilon chapter at Missouri S&T completed construction of a new chapter house on Fraternity Row where the old Delta Sigma ...
... sigma ^{2}}}\right),{\text{ where }}\sigma ={\begin{cases}\sigma _{1},&x,\mu ,\\\sigma _{2},&x\geq \mu .\end{cases}}}. That is ... K is a scaling factor (usually 1 or 100), and λ. {\displaystyle \lambda }. is the wavelength of the equivalent monochromatic ... displaystyle g(x;\alpha ,\mu ,\sigma _{1},\sigma _{2})=\alpha \exp \left({\frac {(x-\mu )^{2}}{-2\ ...
Full Metal Panic! Sigma. *Fushigi Yûgi (Including Fushigi Yûgi Genbu Kaiden). *Fushigiboshi no Futagohime (Twin Princesses of ... Monochrome Factor. *My-HiME. *My Fair Lady known in North America as The Wallflower and Yamato nadeshiko Shichihenge in Japan ...
It was followed by the Six Sigma methodology in the mid-1980s, first introduced by Motorola. Six Sigma consists of statistical ... Paul's Harmon, (2007). Business Process Change: 2nd Ed, A Guide for Business Managers and BPM and Six Sigma Professionals. ...
... and concluded that such a body would form when a star's diameter exceeds the Sun's by a factor of 500, and the surface escape ... known as the M-sigma relation, strongly suggests a connection between the formation of the black hole and the galaxy itself.[ ...
Here, the factor for random waves is 1⁄16, as opposed to 1⁄8 for periodic waves - as explained hereafter. For a small-amplitude ... displaystyle \scriptstyle m_{0}=\sigma _{\eta }^{2}={\overline {(\eta -{\bar {\eta }})^{2}}}={\frac {1}{2}}a^{2},}. the energy ... leading to the factor 1⁄16 in the wave energy density per unit horizontal area.. ...
textstyle {\widehat {\sigma }}}. is the estimate of the standard deviation of the population, and μ is the population mean. ... This approach is sometimes used in observational studies to reduce or eliminate the effects of confounding factors. ... displaystyle t={\frac {Z}{s}}={\frac {{\bar {X}}-\mu }{{\widehat {\sigma }}/{\sqrt {n}}}}}. where X is the sample mean from a ... "noise factors" that are independent of membership in the two groups being compared.[11] In a different context, paired t-tests ...
displaystyle \Sigma }. 이고, 다른 하나는 혼합 계수 벡터 π. {\displaystyle \pi }. 이다. 따라서 μ. {\displaystyle \mu }. 와 Σ. {\displaystyle \Sigma ... displaystyle \mu _{0},\lambda ,\nu ,\sigma _{0}^{2}=}. 공유되는 하이퍼 매개변수. σ. i. =. 1. …. K. 2. ∼. I. n. v. e. r. s. e. -. G. a. m. ... Sigma _{i}}}}})}. 새로운 파라미터들은 ϕ. i. ~. ,. μ. i. ~. {\displaystyle {\tilde {\phi _{i}}},{\boldsymbol {\tilde {\mu _{i}}}}}. and Σ ... displaystyle (\mu _{k},\Sigma _{k}),k=1,...,K}. *k 번째 가우시언의 가중치 π. k. ,. k. =. 1. ,. .. .. .. ,. K. {\displaystyle \pi _{k},k=1 ...
Giddings, Paula (1988). In Search of Sisterhood: Delta Sigma Theta and the Challenges of the Black Sorority Movement. New York ... "one of the most potent factors in the growth of interracial goodwill in America." The Washington Post said: "So great were her ... She was also an honorary member of Delta Sigma Theta sorority.[42] ...
displaystyle U^{*}={\frac {\sigma \epsilon }{2\rho }}{\sqrt {\frac {E}{\rho }}}}. σ. ,. ϵ. ,. ρ. ,. E. {\displaystyle \sigma ,\ ... Many factors have affected the development of personal armor throughout human history. Significant factors in the development ... Because the energy of a bullet is a key factor in its penetrating capacity, velocity is used as the primary independent ... so the weight of the vest is a limiting factor in vest fragment protection. The 2-4-16-64 grain series at limited velocity can ...
displaystyle \sigma _{i}}. of Σ. {\displaystyle \mathbf {\Sigma } }. are known as the singular values of M. {\displaystyle \ ... with eigenvalue scale factors σi along the orthogonal eigenvectors Vi of P, followed by a single rotation (unitary matrix R = ... displaystyle \mathbf {M} =z_{0}\mathbf {I} +z_{1}\sigma _{1}+z_{2}\sigma _{2}+z_{3}\sigma _{3}}. ... Sigma }}^{*}\mathbf {U} ^{*}=\mathbf {U} ({\boldsymbol {\Sigma }}{\boldsymbol {\Sigma }}^{*})\mathbf {U} ^{*}\end{aligned}}}. ...
Rechcigl is a member of the Honor Society of Phi Kappa Phi, member of the Scientific Research Society of the Sigma Xi, member ... 1. Carbohydrates, Lipids, and ccessory Growth Factors. Basel-Munchen-Paris-London-New York-Sydney: S. Karger, 1976. 223 pp. ...
There are also anti-sigma factors that inhibit the function of sigma factors and anti-anti-sigma factors that restore sigma ... Sigma factors in E. coli:. *σ70(RpoD) - σA - the "housekeeping" sigma factor or also called as primary sigma factor, ... The number of sigma factors varies between bacterial species.[1][4] E. coli has seven sigma factors. Sigma factors are ... Region 1.1 is found only in "primary sigma factors" (RpoD, RpoS in E.coli). It is involved in ensuring the sigma factor will ...
... the roles of antisigma factors in controlling the availability of alternative sigma factors and (b) the involvement of diverse ... Regulation of alternative sigma factor use.. Österberg S1, del Peso-Santos T, Shingler V. ... Alternative bacterial sigma factors bind the catalytic core RNA polymerase to confer promoter selectivity on the holoenzyme. ... To form the holoenzymes, the different sigma factors must be available to compete for their common substrate (core RNA ...
... sigma factor There are also anti-sigma factors that inhibit the function of sigma factors and anti-anti-sigma factors that ... Sigma factors in E. coli: σ70(RpoD) - σA - the "housekeeping" sigma factor or also called as primary sigma factor (Group 1), ... The number of sigma factors varies between bacterial species. E. coli has seven sigma factors. Sigma factors are distinguished ... A sigma factorfactor or specificity factor) is a protein needed for initiation of transcription in bacteria. It is a ...
Structure and function of bacterial sigma factors.. Helmann JD1, Chamberlin MJ. ...
Initiation of transcription in bacteria only occurs upon the binding of a key component known as the sigma factorfactor) to ... σ factors. Sigma factors are commonly known to be intrinsically active, which means that the bacterial cell has to keep them in ... Usually, alternative σ factors stay retained in an inactive state by sequestration into a complex with an anti-σ factor. Upon a ... The sleeping Sigma-Factor. A previously unknown mechanism enables bacterial antibiotic resistance ...
Similar proteins: Anti-sigma F factor (B0K150) Showing 1 to 20 of 57508 results ... Anti-sigma F factor. Bacillus cytotoxicus (strain DSM 22905 / CIP 110041 / 391-98 / NVH 391-98). Loading... ... Anti-sigma F factor. Clostridium kluyveri (strain ATCC 8527 / DSM 555 / NCIMB 10680). Loading... ... Anti-sigma F factor. Bacillus velezensis (strain DSM 23117 / BGSC 10A6 / FZB42). Loading... ...
Factor Xa plays a critical role in the coagulation cascade by catalyzing the proteolytic conversion of prothrombin to active ... The extrinsic pathway utilizes a complex of factor VII and tissue factor. The factor X zymogen is a 55 KDa glycoprotein with a ... Factor Xa is a serine endoproteinase and a member of the S1 peptidase family. Factor Xa plays a critical role in the ... Inherited factor X deficiency is an extremely rare disease. However, acquired decreased levels of factor X can be the result of ...
Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then ... sigma factor activity Source: UniProtKB-KW. *transcription factor activity, sequence-specific DNA binding Source: UniProtKB- ... Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then ... IPR014284. RNA_pol_sigma-70_dom. IPR014322. RNA_pol_sigma-B/F/G. IPR014236. RNA_pol_sigma-F. IPR000943. RNA_pol_sigma70. ...
Sigma-Aldrich Products are sold exclusively through Sigma-Aldrich, Inc. Site Use Terms , Privacy ... Hepatocyte Growth Factor (HGF) Product Description. Source. Recombinant Host. Physical Form. Assay. Cell Type Affected. Cat. No ... Hepatocyte Growth Factor. human. mouse NSO cells. lyophilized powder. The biological activity is measured by its ability to ... Hepatocyte Growth Factor. human. Baculovirus infected High-5 cells. lyophilized powder. The biological activity is measured by ...
... different transcriptional factor and sigma factor interact with their correspondent anti-sigma factor. Third, anti-sigma factor ... Each sigma factor has an associated anti-sigma factor which regulates it. These anti-sigma factors are divided into either ... factor affect by several mechanism such as add up anti-sigma factor between sigma or twist the anti-sigma factor around sigma.[ ... anti-sigma factors bind to sigma factors and inhibit transcriptional activity. Anti-sigma factors have been found in a number ...
Domain architectures: RNA polymerase sigma factor RpoD (IPR028630). Showing 1 to 20 of 52 results ...
A stationary-phase stress-response sigma factor from Mycobacterium tuberculosis. J DeMaio, Y Zhang, C Ko, D B Young, W R Bishai ... A stationary-phase stress-response sigma factor from Mycobacterium tuberculosis. J DeMaio, Y Zhang, C Ko, D B Young, W R Bishai ... A stationary-phase stress-response sigma factor from Mycobacterium tuberculosis. J DeMaio, Y Zhang, C Ko, D B Young, and W R ... Alternative RNA polymerase sigma factors are a common means of coordinating gene regulation in bacteria. Using PCR ...
sigma factor definition: nounA protein component of bacterial RNA polymerase that recognizes the correct site on DNA for ... sigma factor. sigma factor. noun. A protein component of bacterial RNA polymerase that recognizes the correct site on DNA for ... How would you define sigma factor? Add your definition here.. Please enable JavaScript to view the comments powered by Disqus. ...
Sigma factors control global switches of the genetic expression program in bacteria. Different sigma factors compete for ... Sigma factor competition is not strongly affected by non-specific binding of core RNAPs, sigma factors and holoenzymes to DNA. ... Sigma factors control global switches of the genetic expression program in bacteria. Different sigma factors compete for ... Mauri, M., & Klumpp, S. (2014). A Model for Sigma Factor Competition in Bacterial Cells. PLoS Computational Biology, 10(10). ...
... Biochimie. Jun-Jul 2000;82(6-7):537-48. doi: 10.1016/s0300-9084(00)00611-8. ... In this review I will outline progress made to date in identifying and characterizing the sigma-like factors of plants, and in ... Recent results suggest that accumulation of individual sigma-like factors is controlled by light, by plastid type and/or by a ... More recently this achievement has extended to the identification of families of sigma-like factor genes from several species ...
... family of sigma factors (33, 34). To test the ability of TxeR to act as a sigma factor, we performed gel mobility-shift assays ... to RNA polymerase sigma factors (data not shown). Our conclusion that TxeR is a sigma factor rather than a positive regulator ... TxeR, an alternative sigma factor, activates transcription of the toxA and toxB genes by directing RNA polymerase core enzyme ... 5A), indicating that the core enzyme was devoid of the major vegetative sigma factor and that any effect of TxeR would be ...
This sigma factor is the primary sigma factor during exponential growth. UniProt ... Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then ...
The PDB archive contains information about experimentally-determined structures of proteins, nucleic acids, and complex assemblies. As a member of the wwPDB, the RCSB PDB curates and annotates PDB data according to agreed upon standards. The RCSB PDB also provides a variety of tools and resources. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists.
This sigma factor is the primary sigma factor during exponential growth. ... Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then ... Interactions between sigma-70 factor domain-4 and anti-sigma factors prevents interaction of sigma factors with the RNA ... This sigma factor is the primary sigma factor during exponential growth.UniRule annotation. ,p>Manual validated information ...
... PLoS Pathog. 2015 Apr 29;11( ... We were able to demonstrate that SigB is the crucial factor for adaptation in chronic infections. During acute infection, the ... Indeed agr and sarA deletion mutants expressed a much lower number of virulence factors and could persist at high numbers ... In this study we identified SigB as an essential factor that enables the bacteria to switch from the highly aggressive ...
sporulation sigma factors G, E, and K have been cloned and sequenced. Indirect evidence for the existence of sigma F was ... Sporulation and primary sigma factor homologous genes in Clostridium acetobutylicum.. U Sauer, A Treuner, M Buchholz, J D ... Sporulation and primary sigma factor homologous genes in Clostridium acetobutylicum.. U Sauer, A Treuner, M Buchholz, J D ... Sporulation and primary sigma factor homologous genes in Clostridium acetobutylicum.. U Sauer, A Treuner, M Buchholz, J D ...
We have shown that the SigH staphylococcal sigma factor is a likely key component for competence development, but that its gene ...
sigma B (sigma 37) is a secondary species of RNA polymerase sigma factor found in the gram-positive bacterium Bacillus subtilis ... Genetic studies of a secondary RNA polymerase sigma factor in Bacillus subtilis.. M Igo, M Lampe, C Ray, W Schafer, C P Moran, ... Genetic studies of a secondary RNA polymerase sigma factor in Bacillus subtilis. ... Genetic studies of a secondary RNA polymerase sigma factor in Bacillus subtilis. ...
... sigma factor SigK. ECF sigma factors are held in an inactive form by an anti-sigma factor until released by regulated ... An anti-sigma factor for extracytoplasmic function (ECF) ... sigma factor SigK. ECF sigma factors are held in an inactive ... a case study of Mycobacterium tuberculosis sigma/anti-sigma factor protein complexes.". Thakur K.G., Jaiswal R.K., Shukla J.K. ... Anti-sigma-K factor RskAAdd BLAST. 231. Amino acid modifications. Feature key. Position(s). DescriptionActions. Graphical view ...
The extra cytoplasmic function sigma factor sigma(E) is essential for Mycobacterium tuberculosis virulence in mice.; Infect ... Sigma factors are components of the RNA polymerase complex that are responsible for binding to the RNA polymerase complex, ... The number of sigma factors is extremely diverse between bacteria, ranging from three in Helicobacter pylori to 63 in ... Collins DM, Kawakami RP, de Lisle GW, Pascopella L, Bloom BR, Jacobs WR Jr; Mutation of the principal sigma factor causes ...
... sigma (σ) factors, which remains unexplored due to limited structural evidence. Our previous study on the structural features ... Identification of a suitable promoter for the sigma factor of Mycobacterium tuberculosis A. Mallick Gupta, S. Mukherjee, A. ... Identification of a suitable promoter for the sigma factor of Mycobacterium tuberculosis ... Promoter binding specificity is one of the important characteristics of transcription by Mycobacterium tuberculosis (Mtb) sigma ...
... sigma factor, SigG. ECF sigma factors are responsible for upregulating genes necessary for bacterial stress responses. SigG has ... Potential anti-sigma factors to SigG were identified, the most promising of which was the thioredoxin family protein Rv1084. ... In bacteria this enzyme recognises different promoters by binding to sigma factors that recognise those promoters. This study ... and anti-anti-sigma factors to SigG. Protein-protein interaction studies showed that SigG and Rv0181c do not interact. ...
Seemingly subtle differences in the precise definition and construction of a risk factor can create meaningful divergences in ... Two Sigma® and the Two Sigma logo are registered trademarks of Two Sigma Investments, LP. Beaker® is a registered trademark of ... factor definition and factor construction.. Factor definition describes the observable asset characteristics (e.g., "book value ... Factor construction describes the design and implementation to compose a specific factors definition. Even for a well-known ...
Stress-Induced Mutation Rates Show a Sigmoidal and Saturable Increase Due to the RpoS Sigma Factor in Escherichia coli. Ram ... Stress-Induced Mutation Rates Show a Sigmoidal and Saturable Increase Due to the RpoS Sigma Factor in Escherichia coli. Ram ... Stress-Induced Mutation Rates Show a Sigmoidal and Saturable Increase Due to the RpoS Sigma Factor in Escherichia coli. Ram ... 2010 RpoS, the stress response sigma factor, plays a dual role in the regulation of Escherichia colis error-prone DNA ...
RNA sequencing was used to predict 3084 operons in the genome of this bacterium, including 11 for ECF sigma factors, and to ... sigma factors in multiple metal homeostasis of the metallophilic bacterium Cupriavidus metallidurans was studied. ... All 11 ECF sigma factors were involved in metal homeostasis. The three ECF sigma factors RpoI, RpoJ and RpoK synchronized iron ... All 11 ECF sigma factors overlap in their function and control gene expression involved in metal homeostasis, however, except ...
  • There are also anti-sigma factors that inhibit the function of sigma factors and anti-anti-sigma factors that restore sigma factor function. (wikipedia.org)
  • σ38 (RpoS) - the starvation/stationary phase sigma factor σ54 (RpoN) - the nitrogen-limitation sigma factor There are also anti-sigma factors that inhibit the function of sigma factors and anti-anti-sigma factors that restore sigma factor function. (wikipedia.org)
  • In the regulation of gene expression in prokaryotes, anti-sigma factors bind to sigma factors and inhibit transcriptional activity. (wikipedia.org)
  • Anti-sigma factors have been found in a number of bacteria, including Escherichia coli and Salmonella, and in the T4 bacteriophage. (wikipedia.org)
  • Anti-sigma factors are antagonists to the sigma factors, which regulate numerous cell processes including flagellar production, stress response, transport and cellular growth. (wikipedia.org)
  • For example, anti-sigma factor 70 Rsd in E. coli is present in the stationary phase and blocks the activity of sigma factor 70 which in essence initiates gene transcription. (wikipedia.org)
  • Sigma factor is an important protein which starts the transcription by binding with RNAP, anti-sigma factor is a protein which inhibits the activities of sigma factor affect by several mechanism such as add up anti-sigma factor between sigma or twist the anti-sigma factor around sigma. (wikipedia.org)
  • Each sigma factor has an associated anti-sigma factor which regulates it. (wikipedia.org)
  • These anti-sigma factors are divided into either cytoplasmic or inner membrane bound anti-sigma factors. (wikipedia.org)
  • Inner membrane bound anti-sigma factors are made up of FecR & RseA. (wikipedia.org)
  • Anti-sigma factors are simultaneously transcribed with their associated sigma factor. (wikipedia.org)
  • As an example of a mechanism function of Anti-Sigma factors that it usually can play an important role instead of being a sigma factors destroyers since they inhibit some cell processes and activate another depending on some researches has been done. (wikipedia.org)
  • Researchers have studied several anti-sigma factor activities in the cell such as RsrA (Redox-sensitive), which is a key sensor of thiol-disulphide and a negative regulator ofσR (binds σR and inhibits σR-directed transcription only in vitro), what means that it needs some sensitive conditions to happen. (wikipedia.org)
  • Second, different transcriptional factor and sigma factor interact with their correspondent anti-sigma factor. (wikipedia.org)
  • Third, anti-sigma factor has different roles: either stay not active or activate it in specific environmental signal. (wikipedia.org)
  • Finally, since the signals disappear, anti-sigma factor inhibit the sigma factor by confinement. (wikipedia.org)
  • Each one specific anti-sigma factors, check the below table for details: As another Anti-sigma factor example is σH which regulate the somatic stress response and the morphological differentiation in S treptomyces coelicolor as the studies results. (wikipedia.org)
  • From the same study it can be concluded that every anti-sigma factor has a specific gene location to act and affect in the cell. (wikipedia.org)
  • As a negative feedback interaction, anti-sigma factor in E-coli, help the cell or allow it to control the gene expression in a particular environment terms. (wikipedia.org)
  • T4 bacteriophage uses anti-sigma factor to ruin the Escherichia coli polymerase in order that direct exclusive transcription of its own genes. (wikipedia.org)
  • AsiA is an anti-sigma factor gene that is required for bacteriophage T4 to be developed). (wikipedia.org)
  • Which means that AsiA is an essential anti-sigma factor in bacteriophage. (wikipedia.org)
  • An anti-sigma factor for extracytoplasmic function (ECF) sigma factor SigK. (uniprot.org)
  • ECF sigma factors are held in an inactive form by an anti-sigma factor until released by regulated intramembrane proteolysis (RIP). (uniprot.org)
  • Novel Mycobacterium tuberculosis anti-sigma factor antagonists control sigmaF activity by distinct mechanisms. (wikipathways.org)
  • sigG is co-transcribed with the two downstream genes Rv0181c and Rv0180c, which were hypothesised to be anti- and anti-anti-sigma factors to SigG. (bl.uk)
  • Potential anti-sigma factors to SigG were identified, the most promising of which was the thioredoxin family protein Rv1084. (bl.uk)
  • We show that the relative stoichiometry of the synthesis rates of σ, its anti-sigma factor RsbW and the anti-anti-sigma factor RsbV plays a critical role in shaping the network behavior by forcing the σnetwork to function as an ultrasensitive negative feedback loop. (rice.edu)
  • In this thesis, I describe the characterization of a sigma factor and anti-sigma factor implicated in P. aeruginosa virulence and cell envelope stress that control the expression of a novel regulator of swarming motility and biofilm formation. (harvard.edu)
  • The gene encoding an ECF sigma factor is often cotranscribed with its own negative regulator, called an anti-sigma factor, which directly binds to and inhibits its partner sigma factor until the appropriate extracytoplasmic signal stimulates sigma factor release and expression of the sigma factor's regulon. (harvard.edu)
  • In this thesis, I describe the characterization of the P. aeruginosa ECF sigma factor PA2896 and its cognate anti-sigma factor PA2895. (harvard.edu)
  • Genetic analysis revealed a subset of genes within the PA2896 regulon that share the putative promoter consensus sequence are positively regulated by the ECF sigma factor PA2896 and negatively regulated by the anti-sigma factor PA2895. (harvard.edu)
  • YlaD, a membrane-anchored anti-sigma factor of Bacillus subtilis , contains a HX 3 CXXC motif that functions as a redox-sensing domain and belongs to one of the zinc-coordinated anti-sigma factor families. (biochemj.org)
  • Below are the list of possible Anti-sigma-L factor products. (mybiosource.com)
  • Also known as Anti-sigma-L factor RslA (Regulator of SigL) (Sigma-L anti-sigma factor RslA). (mybiosource.com)
  • Also known as Anti-sigma-I factor RsgI6 (Endo-1,4-beta-xylanase). (mybiosource.com)
  • Anti-sigma factor for SigI7. (mybiosource.com)
  • A subfamily, the extracytoplasmic function (ECF) sigma factors, which form a widely distributed bacterial signal transduction system comprising a sigma factor and a cognate membrane-embedded anti-sigma factor, regulates genes in response to stressors that threaten cell envelope integrity including the cell wall and membrane. (go.jp)
  • This review focuses on the function and regulation of ECF sigma factors in B . subtilis , in which anti-sigma factors play a role in connecting an external stimulus with gene regulation. (go.jp)
  • In Mycobacterium tuberculosis, RshA is an anti-sigma factor that negatively regulates the heat/oxidative stress response mechanisms. (microbiologyresearch.org)
  • AlgW then degrades the anti-sigma factor MucA thus releasing the alternative sigma factor AlgU/T (σ 22 ) to initiate transcription of the alginate biosynthetic operon. (biomedcentral.com)
  • Promoters of the rshA (anti-sigma for σ H ) and trxB1 (thioredoxin) genes were found to be σ H -dependent, whereas the promoter of the sigB gene (sigma factor σ B ) was σ E - and σ H -dependent. (springeropen.com)
  • Regulated intramembrane proteolysis in the control of the Bacillus subtilis anti-sigma factor RsiW. (uni-bayreuth.de)
  • The activity of the extracytoplasmic function (ECF)-sigma factor SigW of the Gram-positive soil bacterium Bacillus subtilis is modulated by a specific membrane-bound anti-sigma factor (RsiW). (uni-bayreuth.de)
  • Half of the completed α-proteobacterial genome sequences contain two or more copies of genes encoding σ(EcfG) -like sigma factors, with the primary copy typically located adjacent to genes coding for a cognate anti-sigma factor (NepR) and two-component response regulator (PhyR). (fmach.it)
  • This mucoid phenotype can be suppressed by overexpression of the anti-sigma factor MucA [12]. (chromoscience.com)
  • However, data in Figure S1 demonstrate that induction of FlgM, which is the anti-sigma factor for RpoF responsible for the transcription initiation of flagella biosynthesis [46], failed to induce mucoidy in PAO1 and CF149. (chromoscience.com)
  • RsrA is an archetypal zinc-binding anti-sigma factor that responds to disulfide stress in the cytoplasm of Actinobacteria. (ox.ac.uk)
  • Results Alginate biosynthesis in Pseudomonas fluorescens was studied in a genomics perspective, using an alginate over-producing strain carrying a mutation in the anti-sigma factor gene mucA. (chalmers.se)
  • Upon ligand binding , the N-terminal signaling domain of such receptors interacts with an inner membrane anti-sigma factor , leading to release of an extracytoplasmic function (ECF) sigma factor , to recruit RNA polymerase to target promoters . (dartmouth.edu)
  • Furthermore , its presumptive anti-sigma factor , Blr4929 , acts as a negative regulator of the symbiosis . (dartmouth.edu)
  • The Streptomyces coelicolor bldG gene encodes a protein showing similarity to the SpoIIAA and RsbV anti-anti-sigma factors of Bacillus subtilis. (macewan.ca)
  • A Membrane-Embedded Amino Acid Couples the SpoIIQ Channel Protein to Anti-Sigma Factor Transcriptional Repression during Bacillus subtilis Sporulation. (peritonitis.us)
  • Here we report that the channel protein SpoIIQ also specifically maximizes σ(G)activity as part of a previously unknown regulatory circuit that prevents σ(G)from activating transcription of the gene encoding its own inhibitor, the anti-sigma factor CsfB. (peritonitis.us)
  • FlgM proteins, also known as Anti-sigma-28 factor (σ28), are negative regulators of flagellin synthesis. (naver.com)
  • Overproduction and characterization of the Bacillus subtilis anti-sigma factor FlgM. (naver.com)
  • The C-terminal half of the anti-sigma factor, FlgM, becomes structured when bound to its target, sigma 28. (naver.com)
  • FliA is an alternative sigma factor specific for transcription of the class 3 operons, while FlgM is an anti-sigma factor which binds to FliA and prevents its association with RNA polymerase core enzyme. (elsevier.com)
  • These specialized sigma factors bind the promoters of genes appropriate to the environmental conditions, increasing the transcription of those genes. (wikipedia.org)
  • σ 70 (RpoD) - σ A - the "housekeeping" sigma factor or also called as primary sigma factor , transcribes most genes in growing cells. (wikipedia.org)
  • Every cell has a "housekeeping" sigma factor that keeps essential genes and pathways operating. (wikipedia.org)
  • Sigma factors in E. coli: σ70(RpoD) - σA - the "housekeeping" sigma factor or also called as primary sigma factor (Group 1), transcribes most genes in growing cells. (wikipedia.org)
  • Thus, holoenzyme formation with this alternative σ factor results in the transcription of corresponding stress-response genes. (mpg.de)
  • Only upon phosphorylation on a specific residue is the σ factor activated and able to bind the RNAP in formation of the holoenzyme and consequently drive expression of specific genes. (mpg.de)
  • This allows the sigma S factor to associate with RNA polymerase and direct the expression of the stationary genes. (wikipedia.org)
  • Different sigma factors compete for binding to a limited pool of RNA polymerase (RNAP) core enzymes, providing a mechanism for cross-talk between genes or gene classes via the sharing of expression machinery. (mendeley.com)
  • Based on examples of transcriptional regulation in bacteria, it is proposed that differential activation of sigma factors may provide the nucleus with a mechanism to control expression of groups of plastid genes. (nih.gov)
  • While fractionation studies had identified several candidate sigma factors in purified RNA polymerase preparations, it was only 4 years ago that the first sigma factor genes were cloned from two photosynthetic eukaryotes, both of which were red algae. (nih.gov)
  • More recently this achievement has extended to the identification of families of sigma-like factor genes from several species of vascular plants. (nih.gov)
  • Sporulation and primary sigma factor homologous genes in Clostridium acetobutylicum. (asm.org)
  • Using a PCR-based approach, we have cloned various sigma factor homologous genes from Clostridium acetobutylicum DSM 792. (asm.org)
  • Southern hybridization analysis indicated the presence of sigma D and sigma H homologous genes in C. acetobutylicum. (asm.org)
  • Differential expression of 10 sigma factor genes in Mycobacterium tuberculosis. (wikipathways.org)
  • ECF sigma factors are responsible for upregulating genes necessary for bacterial stress responses. (bl.uk)
  • Mutants carrying multiple deletions in genes for ECF sigma factors were constructed and characterized. (rsc.org)
  • As the regulon of a single sigma factor can be composed of hundreds of genes, sigma factors can provide effective mechanisms for simultaneously regulating expression of large numbers of prokaryotic genes. (asm.org)
  • One newly emerging field is identification of the specific roles of alternative sigma factors in regulating expression of virulence genes and virulence-associated genes in bacterial pathogens. (asm.org)
  • As alternative sigma factors have been shown to regulate expression of both virulence and virulence-associated genes, these proteins can contribute both directly and indirectly to bacterial virulence. (asm.org)
  • The Bacillus subtilis extracytoplasmic function (ECF) sigma factor SigM regulates genes for cell wall synthes. (bioportfolio.com)
  • It is believed that Corynebacterium glutamicum promoters driving transcription of housekeeping genes are recognized by RNAP with the primary sigma factor SigA. (omicsonline.org)
  • Th e primary-like factor SigB is mainly involved in transcription of genes during the transition phase between exponential and stationary growth phases. (omicsonline.org)
  • In bacteria, sigma (σ) factors are essential transcription effectors that direct the RNA polymerase to and activate RNA synthesis at specific genes promoters. (elifesciences.org)
  • All bacterial species encode a single, highly conserved σ factor that drives the expression of house-keeping genes essential for vegetative growth and cell homeostasis. (elifesciences.org)
  • C. glutamicum ATCC 13032 has seven putative sigma factor-encoding genes, including sigA and sigB . (biomedcentral.com)
  • The sigA gene encodes the essential primary sigma factor of C. glutamicum and is responsible for promoter recognition of house-keeping genes. (biomedcentral.com)
  • The real-time PCR analysis revealed that sigD overexpression increased the expression of genes related to corynomycolic acid synthesis (fadD2, pks), genes encoding corynomycolyl transferases (cop1, cmt1, cmt2, cmt3), L, D-transpeptidase (lppS), a subunit of the major cell wall channel (porH), and the envelope lipid regulation factor (elrF). (uni-bielefeld.de)
  • As a result, BCN5 synthesis is induced by treatment with UV light or mitomycin C. UviA is related to a special class of sigma factors found to date only in Clostridium species and responsible for activating transcription of toxin genes in Clostridium difficile, Clostridium tetani, and Clostridium botulinum. (pasteur.fr)
  • Comparison with σ-factor binding in Klebsiella pneumoniae showed that transcriptional regulation of conserved genes in closely related species is unexpectedly divergent. (biomedcentral.com)
  • Expansion of the sigma factor gene family appears to have preferentially occurred within the extracytoplasmic function (ECF) sigma factor genes, while the primary alternative (PA) sigma factor genes are, in general, highly conserved with those found in B. subtilis . (biomedcentral.com)
  • Sigma factors are thus key regulatory elements that control different classes of promoters and activate expression of the respective groups of genes (regulons or sigmulons). (springeropen.com)
  • Bacteria typically possess a primary σ factor that is responsible for the transcription of housekeeping genes and a variable number of alternative σ factors that enable the cell to cope with various environmental stimuli. (springeropen.com)
  • Binds to the sigma-S subunit of RNA polymerase, activating expression of sigma-S-regulated genes. (icr.ac.uk)
  • This sigma factor controls the expression of flagella-related genes. (icr.ac.uk)
  • We demonstrate that both sigma factors control unique yet also shared target genes, corroborating phenotypic evidence. (fmach.it)
  • TxeR, a sigma factor that directs Clostridium difficile RNA polymerase to recognize the promoters of two major toxin genes, was shown to stimulate its own synthesis. (archives-ouvertes.fr)
  • RNA sequencing of the transcriptome from a strain overexpressing the sigD gene provided 29 potential sigma(D)-controlled genes and enabled us to precisely localize their transcriptional start sites. (uni-bielefeld.de)
  • Analysis of the respective promoters by both in vitro transcription and the in vivo two-plasmid assay confirmed that transcription of 11 of the tested genes is directly sigma(D)-dependent. (uni-bielefeld.de)
  • In addition to the activity of sigma(H) at the sigma(D)-controlled promoters, we discovered separated or overlapping sigma(A) - or sigma(B)-regulated or sigma(H)-regulated promoters within the upstream region of 8 genes of the sigma(D)-regulon. (uni-bielefeld.de)
  • We found that phenol in the cultivation medium acts as a stress factor inducing expression of some sigma(D)-dependent genes. (uni-bielefeld.de)
  • The presented data obtained by integrating in vivo, in vitro and in silico approaches demonstrate that most of the sigma(D)-controlled genes also belong to the sigma(H)-regulon and are also transcribed from the overlapping or closely located housekeeping (sigma(A)-regulated) and/or general stress (sigma(B)-regulated) promoters. (uni-bielefeld.de)
  • The involvement of the sigma factor RpoH1 in the regulation of S. meliloti genes upon pH stress was analyzed by comparing time-course experiments of the wild type and the rpoH1 mutant. (beds.ac.uk)
  • Finally, the third class of S. meliloti genes was regulated in a complex manner, which indicates that besides sigma factor RpoH1, further regulation takes place. (beds.ac.uk)
  • Clustering of time-course microarray data of S. meliloti wild type and sigma factor rpoH1 mutant allowed for the identification of gene clusters, each with a unique time-dependent expression pattern, as well as for the classification of genes according to their dependence on RpoH1 expression and regulation. (beds.ac.uk)
  • Most dysregulated genes belonged to six functional classes, including the "chaperones and heat shock proteins", "antibiotic resistance and susceptibility", "energy metabolism", "protein secretion/export apparatus", and "secreted factors", and "motility and attachment" classes. (inrs.ca)
  • Phosphate starvation relayed by PhoB activates the expression of the Pseudomonas aeruginosa σvreI ECF factor and its target genes. (openrepository.com)
  • Chloroplast genes are embedded in the regulatory network of the cell enabling an adaptive and developmentally regulated chloroplast biogenesis, which is mainly controlled by nuclear factors (Stern et al. (springer.com)
  • The evolution of the psbB cluster genes (Fig. 1 ), along with functions of the encoded proteins and known factors for transcript processing and stability events (Fig. 2 ) will be elaborated in this review. (springer.com)
  • The deduced protein encoded by sigF shows significant similarity to SigF sporulation sigma factors from Streptomyces coelicolor and Bacillus subtilis and to SigB, a stress-response sigma factor, from B. subtilis. (pnas.org)
  • The putative sigA gene product shows high homology to primary sigma factors of various bacteria, most significantly to Bacillus subtilis and Staphylococcus aureus. (asm.org)
  • A promoter sequence with significant homology to the sigma H-dependent Bacillus promoters preceded the determined transcriptional start point, 182 bp upstream of the GUG start codon of dnaE. (asm.org)
  • Indirect evidence for the existence of sigma F was obtained by identification of a DNA sequence homologous to the respective Bacillus consensus promoter. (asm.org)
  • Genetic studies of a secondary RNA polymerase sigma factor in Bacillus subtilis. (asm.org)
  • sigma B (sigma 37) is a secondary species of RNA polymerase sigma factor found in the gram-positive bacterium Bacillus subtilis. (asm.org)
  • Deciphering the essentiality and function of the anti-σ factors in Bacillus subtilis. (bioportfolio.com)
  • Here we investigate one of the best-studied examples of alternative sigma factors: the σnetwork that controls the general stress response of Bacillus subtilis to uncover widely relevant general design principles that describe the structure-function relationship of alternative sigma factor regulatory networks. (rice.edu)
  • The Gram-positive soil bacterium Bacillus subtilis provides a valuable model for investigation of the ECF sigma factors. (go.jp)
  • Late gene expression in the developing Bacillus subtilis spore is directed by the alternative sigma factor σ(G) The activity of σ(G)requires a channel apparatus through which the adjacent mother cell provides substrates that generally support gene expression. (peritonitis.us)
  • Nickel in the structure of Crystal Structure of A Putative Ecf-Type Sigma Factor Negative Effector From Bacillus Anthracis Str. (atomistry.com)
  • Every molecule of RNA polymerase holoenzyme contains exactly one sigma factor subunit, which in the model bacterium Escherichia coli is one of those listed below. (wikipedia.org)
  • A sigma factor toolbox for orthogonal gene expression in Escherichia coli : enabling modular control of complex heterologous pahtways," in SEED : Synthetic Biology: Engineering, Evolution and Design, Conference program book , Scottsdale, AZ, USA, 2018. (ugent.be)
  • Transcriptional switching in Escherichia coli during stress and starvation by modulation of sigma activity. (semanticscholar.org)
  • Recent studies with Myxococcus xanthus have suggested that homologues of the Escherichia coli heat-shock sigma factor, RpoH, may not be involved in the heat-shock response in this delta-proteobacterium. (umass.edu)
  • Using multiple genome-scale measurements, we elucidated the network of σ-factor and promoter interactions in Escherichia coli . (biomedcentral.com)
  • lacZ transcriptional fusion, we demonstrate that the RpoN σ factor can function in Escherichia coli to increase pilE transcription when the NifA activator from Klebsiella is present in trans. (elsevier.com)
  • In particular, there are significant differences to the inducing stress-signal and the site-1 protease that are described for the well investigated Escherichia coli ECF sigma factor SigE-system. (uni-bayreuth.de)
  • [1] In the case of E. coli and other gram-negative rod-shaped bacteria, the "housekeeping" sigma factor is σ 70 . (wikipedia.org)
  • σ 32 (RpoH) - the heat shock sigma factor, it is turned on when the bacteria are exposed to heat. (wikipedia.org)
  • σ19 (FecI) - the ferric citrate sigma factor, regulates the fec gene for iron transport and metabolism σ24 (RpoE) - extreme heat stress response and the extracellular proteins sigma factor σ28 (RpoF/FliA) - the flagellar synthesis and chemotaxis sigma factor σ32 (RpoH) - the heat shock sigma factor, it is turned on when the bacteria are exposed to heat. (wikipedia.org)
  • Initiation of transcription in bacteria only occurs upon the binding of a key component known as the sigma factor (σ factor) to the RNA polymerase (RNAP) core enzyme in order to form the complete and catalytically active holoenzyme. (mpg.de)
  • Transcriptional regulation by σ-factor phosphorylation is a conserved mechanism in bacteria. (mpg.de)
  • Alternative RNA polymerase sigma factors are a common means of coordinating gene regulation in bacteria. (pnas.org)
  • Sigma factors control global switches of the genetic expression program in bacteria. (mendeley.com)
  • In this study we identified SigB as an essential factor that enables the bacteria to switch from the highly aggressive phenotype that settles an acute infection to a silent SCV-phenotype that allows for long-term intracellular persistence. (nih.gov)
  • The number of sigma factors is extremely diverse between bacteria, ranging from three in Helicobacter pylori to 63 in Streptomyces coelicolor. (wikipathways.org)
  • In bacteria this enzyme recognises different promoters by binding to sigma factors that recognise those promoters. (bl.uk)
  • Bacteria use alternative sigma factors to adapt to different growth and stress conditions. (bioportfolio.com)
  • In bacteria, RNA polymerase (RNAP) requires sigma factors for promoter-specific transcription initiation. (harvard.edu)
  • Most bacteria encode a primary sigma factor and several alternative sigma factors, each of which recognizes different promoter -10 and -35 sequences. (harvard.edu)
  • By modulating the activity of alternative sigma factors, bacteria can rapidly alter their transcriptional program in response to changes in growth, morphological development, and environmental conditions. (harvard.edu)
  • In addition, many bacteria encode a variable set of alternative σ factors that control specific regulons, providing appropriate properties to the cells in response to various stimuli. (elifesciences.org)
  • These alternative σ factors play pivotal roles in the multifaceted lifestyles of bacteria. (elifesciences.org)
  • Under normal growth conditions, bacteria use generally a RNA polymerase holoenzyme containing the principal sigma factor SigA. (biomedcentral.com)
  • Background Sigma factors are one of the components of RNA polymerase holoenzymes, and an essential factor of transcription initiation in bacteria. (uni-bielefeld.de)
  • In bacteria, one primary and multiple alternative sigma (σ) factors associate with the RNA polymerase core enzyme (E) to form holoenzymes (Eσ) with different promoter recognition specificities. (pasteur.fr)
  • With systems biology and genome-scale science emerging and describing the phenotypic functions of bacteria, it is now possible to comprehensively elucidate the structure of the σ-factor network. (biomedcentral.com)
  • The multisubunit RNA polymerase (RNAP) holoenzyme in bacteria consists of core enzyme (2α, β, β′ and ω subunits) and a dissociable σ subunit (σ factor) that recognizes specific promoter sequences. (springeropen.com)
  • Our primary research focus is to identify and characterize signal transducing systems (two-component systems, TCSs, and extracytoplasmic function sigma factors, ECFs) involved in mediating bacterial stress responses with a special emphasize on HOW bacteria detect their input signal, i.e. the mechanism of stimulus perception. (tu-dresden.de)
  • Bacteria usually display two distinct responses to stress conditions: a response that controls the conditions in the cytoplasm, which is orchestrated by the alternative sigma factor σ 32 , and a response to the conditions in the periplasm, which is orchestrated by the alternative sigma factor σ E [ 2 ]. (beds.ac.uk)
  • Sigma factors are essential global regulators of transcription initiation in bacteria which confer promoter recognition specificity to the RNA polymerase core enzyme. (openrepository.com)
  • Extracytoplasmic function or ECF sigma factors are the most abundant class of alternate sigma factors in bacteria. (bibr-1048.info)
  • However, in collaboration with researchers from SYNMIKRO in Marburg, the Max Planck researchers have revealed a previously unknown mechanism of transcriptional regulation, which instead relies on intrinsically inactive σ factors that are unable to bind the RNAP core enzyme. (mpg.de)
  • Triple transcriptional control of the resuscitation promoting factor 2 (rpf2) gene of Corynebacterium glutamicum by the regulators of acetate metabolism RamA and RamB and the cAMP-dependent regulator GlxR. (semanticscholar.org)
  • sigma factors are those portions of the bacterial transcriptional apparatus that control RNA polymerase recognition for promoter selection. (biomedcentral.com)
  • Thus, examining sigma factor divergence in these organisms would concurrently examine both regulatory sequences and transcriptional networks important for divergence. (biomedcentral.com)
  • Divergence of the sigma-controlled transcriptional regulons among various members of the Bc species-group likely has a major role in explaining the diversity of phenotypic characteristics seen in members of the Bc species-group. (biomedcentral.com)
  • In vitro transcription assays and measurements of promoter activity using the overexpression of a single sigma factor gene and the transcriptional fusion of the promoter to the gfp uv reporter gene enabled us to reliably define the sigma factor dependency of promoters. (springeropen.com)
  • Since the activities of the different holo-RNAPs and the respective promoters orchestrate the cell metabolism in complex responses to various nutrition, growth and stress conditions, engineering σ factors has recently become a promising field in biotechnology and synthetic biology, particularly for the development of synthetic transcriptional control (Rhodius et al. (springeropen.com)
  • This response is mediated by global regulatory mechanisms that operate in an effective method of transcriptional control, with the participation of specialized RNA polymerase subunits, the alternative sigma factors [ 1 ]. (beds.ac.uk)
  • We furthermore elucidated the de novo binding motif of each sigma factor, and validated the RNA- and ChIP-seq results by global motif searches in the proximity of transcriptional start sites (TSS). (openrepository.com)
  • Numerous nuclear-encoded factors have been acquired for processing and other post-transcriptional modifications of plastid transcripts (Stern et al. (springer.com)
  • The alternative σ factor RpoS/σ is produced in stationary phase and under stress conditions and reprograms global gene expression to promote bacterial survival. (pasteur.fr)
  • Role of the stress sigma factor RpoS in GacA/RsmA-controlled secondary metabolism and resistance to oxidative stress in Pseudomonas fluorescens CHA0. (microbiologyresearch.org)
  • Signal transduction and regulatory mechanisms involved in control of the sigma(S) (RpoS) subunit of RNA polymerase. (microbiologyresearch.org)
  • In addition, c5038 and kgtP expression were further shown to be controlled by different alternative sigma factors RpoN and RpoS, respectively. (frontiersin.org)
  • Borrelia burgdorferi Requires the Alternative Sigma Factor RpoS for Di" by Star M. Dunham-Ems, Melissa J. Caimano et al. (uconn.edu)
  • Dunham-Ems SM, Caimano MJ, Eggers CH, Radolf JD (2012) Borrelia burgdorferi Requires the Alternative Sigma Factor RpoS for Dissemination within the Vector during Tick-to-Mammal Transmission. (uconn.edu)
  • This sigma factor is the primary sigma factor during exponential growth. (rcsb.org)
  • The Corynebacterium glutamicum genome codes for 7 sigma subunits (factors) of RNA polymerase (RNAP): primary sigma factor SigA (σ(A)), primary-like SigB and 5 other alternative sigma factors (SigC, SigD, SigE, SigH and SigM). (semanticscholar.org)
  • The C. glutamicum genome encodes seven sigma subunits (factors) of RNA polymerase: the primary sigma factor SigA (σ A ), the primary-like σ B and five alternative sigma factors (σ C , σ D , σ E , σ H and σ M ). We have developed in vitro and in vivo methods to assign particular sigma factors to individual promoters of different classes. (springeropen.com)
  • The C. glutamicum genome encodes seven sigma subunits of RNAP: the primary sigma factor σ A , the alternative primary-like σ B and five other alternative σ factors with extracytoplasmic functions (ECF) (σ C , σ D , σ E , σ H and σ M ) (for a review, see Pátek and Nešvera 2011 ). (springeropen.com)
  • The sigma(D) regulon is involved in the synthesis of components of the mycomembrane which is part of the cell wall in C. glutamicum. (uni-bielefeld.de)
  • Identification of the alternative sigma factor SigX regulon and its implications for Pseudomonas aeruginosa pathogenicity. (openrepository.com)
  • In the sigB mutant, however, the transcription profiles resembled that of the sigA gene encoding the house-keeping sigma factor. (biomedcentral.com)
  • The typical housekeeping promoter P2 sigA (sigma factor σ A ) was proven to be σ A -dependent but also recognized by σ B . Similarly, the promoter of fba (fructose-1,6-bisphosphate aldolase) was confirmed to be σ B -dependent but also functional with σ A . The study provided demonstrations of the broad applicability of the developed methods and produced original data on the analyzed promoters. (springeropen.com)
  • The core RNA polymerase (consisting of 2 alpha (α), 1 beta (β), 1 beta-prime (β'), and 1 omega (ω) subunits) binds a sigma factor to form a complex called the RNA polymerase holoenzyme. (wikipedia.org)
  • The holoenzyme contains a catalytic core composed of plastid-encoded subunits, assembled with a nuclear-encoded promoter-specificity factor, sigma. (nih.gov)
  • Sigma factors are a class of proteins constituting essential dissociable subunits of prokaryotic RNA polymerase. (asm.org)
  • One mechanism controlling plastid transcription involves nuclear-encoded sigma subunits of plastid-encoded plastid RNA polymerase. (jic.ac.uk)
  • Diff erent sigma subunits of bacterial RNA polymerase (RNAP) recognize diff erent classes of promoters. (omicsonline.org)
  • Thus, any major shift in the intracellular level of sigma factors can potentially affect mucoid conversion, because the pool of core RNAP, which is made up of five different subunits, must be in a limiting amount inside bacterial cells. (chromoscience.com)
  • Corynebacterium glutamicum ATCC 13032 harbors five sigma subunits of RNA polymerase belonging to Group IV, also called extracytoplasmic function (ECF) sigma factors. (uni-bielefeld.de)
  • The sigma factor in the RNA polymerase holoenzyme complex is required for the initiation of transcription, although once that stage is finished, it is dissociated from the complex and the RNAP continues elongation on its own. (wikipedia.org)
  • To analyze the contribution of sigma factor competition to global changes in gene expression, we develop a theoretical model that describes binding between sigma factors and core RNAP, transcription, non-specific binding to DNA and the modulation of the availability of the molecular components. (mendeley.com)
  • Active transcription effectively lowers the affinity between the sigma factor driving it and the core RNAP, resulting in complex cross-talk effects. (mendeley.com)
  • sigma factors guide RNAP to promoters by recognizing conserved DNA sequences within the promoter called the -10 and -35 elements. (harvard.edu)
  • Using immunoprecipitation, we show that the ECF sigma factor PA2896 and RNAP co-purify in vivo. (harvard.edu)
  • Th e in vitro transcription system consists of the promoter-carrying DNA template and RNAP holoenzyme reconstituted from the purifi ed His-tagged core RNAP and a separately isolated sigma factor. (omicsonline.org)
  • At the beginning of the transcription process, the RNA polymerase (RNAP) core enzyme requires a σ-factor to recognize the genomic location at which the process initiates. (biomedcentral.com)
  • Although the importance of σ-factors and their role in the function of the RNAP and bacterial transcription are well known, we do not yet have a genome-wide understanding of the network of regulatory interactions that the σ-factors comprise in any species. (biomedcentral.com)
  • Diagram shows bacterial transcription process by an RNA polymerase (RNAP) core enzyme and an associated σ-factor. (biomedcentral.com)
  • (c) Datasets used for σ-TUG network reconstruction: ChIP-chip dataset with RNAP and six σ-factors, and the TSS dataset. (biomedcentral.com)
  • We propose that the mechanism for mucoid conversion mediated by AlgU, SspA and RpoD in CF149 may be related to the competition between sigma factors RpoD and AlgU for the core RNAP binding site (Figure 7). (chromoscience.com)
  • Because of the differential binding ability among sigma factors for core RNAP [43], σ factor competition exists within a cell at any given time [44]. (chromoscience.com)
  • Promoter binding specificity is one of the important characteristics of transcription by Mycobacterium tuberculosis (Mtb) sigma (σ) factors, which remains unexplored due to limited structural evidence. (rsc.org)
  • Sigma factors provide promoter recognition specificity to RNA polymerase holoenzyme, contribute to DNA strand separation, and then dissociate from the core enzyme following transcription initiation. (asm.org)
  • Structure of the bacterial RNA polymerase promoter specificity sigma subunit. (expasy.org)
  • Expression of the psbB gene cluster necessitates different processing events along with numerous newly evolved specificity factors conferring stability to many of the processed RNA transcripts, and thus exemplarily shows the complexity of RNA metabolism in the chloroplast. (springer.com)
  • Newly evolved specificity factors confer stability to many of these RNA transcripts by binding to their termini and blocking exoribonucleases. (springer.com)
  • A sigma factor is the promoter specificity subunit of eubacterial-type multisubunit RNA polymerases, those whose core subunit composition is often described as alpha(2)-beta-beta-prime. (cathdb.info)
  • Sigma factors encoded by the nucleus of plants confer promoter specificity on the bacterial-type RNA polymerase in chloroplasts. (elsevier.com)
  • Conclusions This study demonstrated that SigD regulates the synthesis of corynomycolate and related compounds, and expanded the knowledge of regulatory functions of sigma factors in C. glutamicum. (uni-bielefeld.de)
  • RpoN Regulates Virulence Factors of Pseudomonas aeruginosa via Modulating the PqsR Quorum Sensing Regulator. (openrepository.com)
  • We were able to demonstrate that SigB is the crucial factor for adaptation in chronic infections. (nih.gov)
  • One such mutation, called crl, was found to map in or near the structural gene (sigB) for sigma B. To determine directly whether mutations in sigB would prevent transcription of ctc, we replaced sigB in the B. subtilis chromosome with insertion and deletion mutations that disrupted the sigma B coding sequence. (asm.org)
  • The sigB gene codes for the non-essential sigma factor SigB that has a proposed role in stress reponse. (biomedcentral.com)
  • The impact of the alternative sigma factor sigma B (SigB) on pathogenesis of Staphylococcus aureus is not conclusively clarified. (qub.ac.uk)
  • The data strongly indicate that the alternative sigma factor SigB plays a role in CVC-associated infections caused by S. aureus. (qub.ac.uk)
  • SigC, SigD, SigE, SigH and SigM of C. glutamicum are members of the Group 4 sigma factors called also ECF (extracytoplasmic function) sigma factors. (omicsonline.org)
  • This is the first report of the involvement of oxidative stress-responsive B. subtilis extracytoplasmic function sigma factors during sporulation via a manganese-dependent redox-sensing molecular switch. (biochemj.org)
  • A sigma factor ( σ factor ) is a protein needed only for initiation of transcription. (wikipedia.org)
  • Virulent strains of C. difficile generally produce two very large protein toxins (ToxA and ToxB) that have been identified as major virulence factors ( 2 ). (pnas.org)
  • The membrane-spanning regulatory substrate protein is first cut extracytoplasmically (site-1 protease, S1P), then within the membrane itself (site-2 protease, S2P, Rip1), while cytoplasmic proteases finish degrading the regulatory protein, liberating the sigma factor. (uniprot.org)
  • Herein, high resolution X-ray crystallographic structures of the protein-DNA complexes were inspected to determine the tentative DNA-binding helix of the σ factor. (rsc.org)
  • The first wave relies on the stress-inducible phosphorelay between ComD and ComE proteins, and the second on the alternative sigma factor σ X , which directs the expression of the DprA protein that turns off competence through interaction with phosphorylated ComE. (elifesciences.org)
  • Three mucoid mutants were identified with transposon insertions that caused 1) an overexpression of AlgUA61V, 2) an overexpression of the stringent starvation protein A (SspA), and 3) a reduced expression of the major sigma factor RpoD (σ70). (chromoscience.com)
  • Each response deals with the cellular ability to sense protein folding and other signals, and leads to the activation of proteins such as molecular chaperones, proteases, and regulatory factors, which play an important role in promoting homeostasis under stress conditions [ 3 - 5 ]. (beds.ac.uk)
  • SigX, one of the 19 extra-cytoplasmic function sigma factors of P. aeruginosa, was only known to be involved in transcription of the gene encoding the major outer membrane protein OprF. (inrs.ca)
  • In conclusion, the analysis presented in this work will be useful in designing new experiments to understand better protein-protein interactions between FglM, sigma factors, and putative molecules from the flagellar export apparatus. (naver.com)
  • Conversely, RpoD overexpression resulted in suppression of mucoidy in all mucoid strains tested, indicating that sigma factor competition can regulate mucoidy. (chromoscience.com)
  • Altogether, our results indicate that the anti-σ70 factors can induce conversion to mucoidy in P. aeruginosa CF149 with algU-suppressor mutation via modulation of RpoD. (chromoscience.com)
  • Furthermore, the mucoid suppression resulting from the overexpression of RpoD can be attributed to the competition between two sigma factors (Table 2). (chromoscience.com)
  • Table S2 illustrates that sigma factors besides RpoD can also exert the same effect on mucoid suppression in mucA plus and minus mucoid strains. (chromoscience.com)
  • sporulation sigma factors G, E, and K have been cloned and sequenced. (asm.org)
  • of sigma factor sporulation mutant forespore. (uvm.edu)
  • Then σ-factor, a single dissociable subunit, binds to E, forming a holoenzyme (Eσ x , x for each σ-factor) and orchestrates initiation of promoter-specific transcription [ 1 ]. (biomedcentral.com)
  • RNA polymerase, together with one or more general transcription factors , binds to promoter DNA . (wikipedia.org)
  • Computer modeling revealed that sigma(H) binds to the promoter DNA in a similar manner as sigma(D) to the analogous promoter elements. (uni-bielefeld.de)
  • Although sigma does not bind DNA on its own, when combined with the core to form the holoenzyme, this binds specifically to promoter sequences, with the sigma factor making sequence specific contacts with the promoter elements. (cathdb.info)
  • [1] It is a bacterial transcription initiation factor that enables specific binding of RNA polymerase to gene promoters . (wikipedia.org)
  • Once initiation of RNA transcription is complete, the sigma factor can leave the complex. (wikipedia.org)
  • Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. (uniprot.org)
  • The association of appropriate alternative sigma factors with core RNA polymerase provides a mechanism for cellular responses mediated through redirection of transcription initiation. (asm.org)
  • σ 54 forms a distinct subfamily of sigma factors referred to as σ N in almost all species for which these proteins have been characterized to date. (asm.org)
  • Here, we report the identification of two WRKY33-interacting proteins, nuclear-encoded SIGMA FACTOR BINDING PROTEIN1 (SIB1) and SIB2, which also interact with plastid-encoded plastid RNA polymerase SIGMA FACTOR1. (plantcell.org)
  • Proteins belonging to the sigma factor family in eubacteria initiate transcription by associating with RNA polymerase. (go.jp)
  • Due to the higher expression, the factor will bind with a high probability to the polymerase-core-enzyme. (wikipedia.org)
  • It is involved in ensuring the sigma factor will only bind the promoter when it is complexed with the RNA polymerase. (wikipedia.org)
  • Alternative bacterial sigma factors bind the catalytic core RNA polymerase to confer promoter selectivity on the holoenzyme. (nih.gov)
  • S. epidermidis possesses several virulence factors that enable it to bind both abiotic surfaces and host factors t. (bioportfolio.com)
  • Using EMSA it was observed that in the presence of RNA core polymerase, chlamydial sigma 54 could bind to the predicted RpoN promoters. (ku.edu)
  • The current model suggests that extensive interdomain contacts in a free σ factor result in a compact conformation that masks the DNA-binding determinants of σ, explaining why a free σ factor does not bind double-stranded promoter DNA efficiently. (pasteur.fr)
  • Stimulates RNA polymerase holoenzyme formation and may bind to several other sigma factors, such as sigma-70 and sigma-32. (icr.ac.uk)
  • We show that RsrA utilizes its hydrophobic core to bind the sigma factor σR preventing its association with RNA polymerase, and that zinc plays a central role in maintaining this high-affinity complex. (ox.ac.uk)
  • The homology models together with mutational analysis showed that the key amino acids, Ala 60 in sigma(D) and Lys 53 in sigma(H), bind to the second nucleotide within the respective -10 promoter elements (GAT and GTT, respectively). (uni-bielefeld.de)
  • Gene-specific transacting factors encoded in the nucleus can bind the 5′ UTR of mRNAs to protect them against 5′ → 3′ exonucleases (Drager et al. (springer.com)
  • The extra cytoplasmic function sigma factor sigma(E) is essential for Mycobacterium tuberculosis virulence in mice. (wikipathways.org)
  • The extra-cytoplasmic function sigma factor sigX modulates biofilm and virulence-related properties in pseudomonas aeruginosa PLoS ONE , vol. 8 , nº 11. (inrs.ca)
  • We performed in vitro studies to elucidate the role of sigma 54 (RpoN) in Chlamydia trachomatis L2/434/Bu. (ku.edu)
  • The role of sigma(D) consists in the control of cell wall integrity. (uni-bielefeld.de)
  • The combined data suggest a critical role of sigma(B) in S. aureus biofilm regulation under environmental stress conditions. (qub.ac.uk)
  • RNA polymerase holoenzyme complex consisting of core RNA polymerase and a sigma factor executes transcription of a DNA template strand. (wikipedia.org)
  • To form the holoenzymes, the different sigma factors must be available to compete for their common substrate (core RNA polymerase). (nih.gov)
  • Regulation of alternative sigma factor use. (nih.gov)
  • Our discoveries reveal how nature has merged two distinct regulation mechanisms - threonine kinase signaling and regulation of σ factor activity - as joint forces, in order to achieve the ability of environmental adaptation. (mpg.de)
  • We find that passive up-regulation of alternative sigma-dependent transcription is not only possible, but also displays hypersensitivity based on the sigma factor competition. (mendeley.com)
  • The promoter interaction of Mtb-SigH can be highly beneficial for understanding the regulation of gene expression of a pathogen and also extends a solid platform to predict promoters for other bacterial σ factors. (rsc.org)
  • This study focuses on the role and regulation of the M. tuberculosis extracytoplasmic function (ECF) sigma factor, SigG. (bl.uk)
  • All 11 ECF sigma factors overlap in their function and control gene expression involved in metal homeostasis, however, except CnrH, no other ECF sigma factor was needed for up-regulation of 63 predicted operons responding to metal shock, 48 of these encoding metal efflux pumps. (rsc.org)
  • We monitored the regulation of chloroplast transcription in photoreceptor and sigma factor mutants under controlled light regimes in Arabidopsis thaliana. (jic.ac.uk)
  • Despite the central role of alternative sigma factors in bacterial stress response and virulence their regulation remains incompletely understood. (rice.edu)
  • We further demonstrate how this negative feedback regulation insulates alternative sigma factor activity from competition with the housekeeping sigma factor for RNA polymerase and allows multiple stress sigma factors to function simultaneously with little competitive interference. (rice.edu)
  • In particular, we are looking for antisens and non-coding RNAs (RNAseq) and transcription factors responsible of indirect gene regulation, especially negative regulation. (ujf-grenoble.fr)
  • Transcription regulation by the Mycobacterium tuberculosis alternative sigma factor SigD and its role in virulence. (uni-bielefeld.de)
  • The reconstructed network was used to investigate competition between alternative σ-factors (the σ 70 and σ 38 regulons), confirming the competition model of σ substitution and negative regulation by alternative σ-factors. (biomedcentral.com)
  • Alternative transcription factor sigma(B) is involved in regulation of biofilm expression in a Staphylococcus aureus mucosal isolate. (qub.ac.uk)
  • Indeed agr and sarA deletion mutants expressed a much lower number of virulence factors and could persist at high numbers intracellularly. (nih.gov)
  • This review highlights (a) the roles of antisigma factors in controlling the availability of alternative sigma factors and (b) the involvement of diverse regulatory molecules that promote the use of alternative sigma factors through subversion of the domineering housekeeping σ(70). (nih.gov)
  • During external stress conditions, the primary σ factor is replaced by an alternative σ factor, which differs from the former with respect to the promoter sequences that it recognizes. (mpg.de)
  • Among the various classes of alternative σ factors, the most abundant ones are the extracytoplasmic function (ECF) σ factors. (mpg.de)
  • Usually, alternative σ factors stay retained in an inactive state by sequestration into a complex with an anti-σ factor. (mpg.de)
  • TxeR was shown to function as an alternative sigma factor for RNA polymerase. (pnas.org)
  • Here, we present evidence that TxeR is an alternative RNA polymerase sigma factor required for the activation of toxin gene expression in C. difficile . (pnas.org)
  • Some of the alternative names for risk factor investing, such as "smart beta," reinforce this illusion. (twosigma.com)
  • We present several examples of alternative sigma factors that have been shown to contribute to virulence in at least one organism. (asm.org)
  • Alternative sigma factor B (σ) and catalase enzyme contribute to Staphylococcus epidermidis biofilm's tolerance against physico-chemical disinfection. (bioportfolio.com)
  • Chlamydia is known to code for an alternative sigma factor, RpoN, but the role is unknown. (ku.edu)
  • The human pathogen Streptococcus pneumoniae (the pneumococcus) possesses a unique alternative σ factor σ X ( Lee and Morrison, 1999 ). (elifesciences.org)
  • gusA was observed at the late-exponential and early-stationary phase and the ylaC -overexpressing mutant constitutively expressed gene transcripts of clpP and sigH , an important alternative sigma factor regulated by ClpXP. (biochemj.org)
  • The alternative sigma factor sigma B of Staphylococcus aureus modulates virulence in experimental central venous catheter-related infections. (qub.ac.uk)
  • Fingerprint Dive into the research topics of 'The alternative sigma factor sigma B of Staphylococcus aureus modulates virulence in experimental central venous catheter-related infections. (qub.ac.uk)
  • Inactivation of a global regulator of the bacterial stress response, the alternative transcription factor sigma(B), resulted in a biofilm-negative phenotype and loss of salt-induced biofilm production. (qub.ac.uk)
  • He participates on an international project analyzing sigma factors of RNA polymerase in Corynebacterium glutamicum at postdoctoral position in the Institute of Microbiology of Czech Academy of the Sciences. (omicsonline.org)
  • Sigma factors and promoters in Corynebacterium glutamicum. (semanticscholar.org)
  • Extracytoplasmic function sigma factor σD confers resistance to environmental stress by enhancing mycolate synthesis and modifying peptidoglycan structures in Corynebacterium glutamicum. (uni-bielefeld.de)
  • Elucidation of Sigma Factor-Associated Networks in Pseudomonas aeruginosa Reveals a Modular Architecture with Limited and Function-Specific Crosstalk. (openrepository.com)
  • In this study, we constructed nine his-tagged sigma factor expressing and/or deletion mutant strains in the opportunistic pathogen Pseudomonas aeruginosa. (openrepository.com)
  • Our data indicate that the modular structure of sigma factor networks enables P. aeruginosa to function adequately in its environment and at the same time is exploited to build up higher-level functions by specific interconnections that are dominated by a participation of RpoN. (openrepository.com)
  • Sigma factors in Pseudomonas aeruginosa. (openrepository.com)
  • [1] [4] E. coli has seven sigma factors. (wikipedia.org)
  • In prokaryotes, E. coli has seven different sigma factors depends on the environment condition. (wikipedia.org)
  • A reporter gene expression assay examining the expression of chloramphenicol acetyltransferase from the promoter regions from complex cyanobacterial gene clusters was used to show that sigma factor All7608 is capable of recognizing multiple cyanobacterial promoters in E. coli. (oregonstate.edu)
  • Here, we present the results from a systems approach that integrates multiple genome-scale measurements to reconstruct the regulatory network of σ-factor-gene interactions in E. coli . (biomedcentral.com)
  • In this review I will outline progress made to date in identifying and characterizing the sigma-like factors of plants, and in dissecting their potential roles in chloroplast gene expression. (nih.gov)
  • The Mycobacterium tuberculosis ECF sigma factor sigmaE: role in global gene expression and survival in macrophages. (wikipathways.org)
  • The Mycobacterium tuberculosis SigD sigma factor controls the expression of ribosome-associated gene products in stationary phase and is required for full virulence. (wikipathways.org)
  • It is generally observed that under nutrient limitation or under a variety of physical and chemical stresses, additional sigma factors compete for the limited amount of RNA polymerase core enzyme. (biomedcentral.com)
  • Integration of light and circadian signals that regulate chloroplast transcription by a nuclear-encoded sigma factor. (jic.ac.uk)
  • They are functional sigma factors, but they have significantly different primary amino acid sequences. (wikipedia.org)
  • Sequence analysis of their mutation sites revealed that most of them caused the amino acid substitutions in region 4 of the conserved amino acid sequences of sigma factors which lies near the C-terminal end of FliA. (elsevier.com)
  • RNA sequencing was used to predict 3084 operons in the genome of this bacterium, including 11 for ECF sigma factors, and to measure transcript abundances. (rsc.org)
  • Here, we examine the ability of heterologously expressed sigma factors identified in the genome of Anabaena sp. (oregonstate.edu)
  • Although the crucial role of σ-factors has long been appreciated and characterized for many individual promoters, we do not yet have a genome-scale assessment of their function. (biomedcentral.com)
  • The sigma factor, together with RNA polymerase, is known as the RNA polymerase holoenzyme. (wikipedia.org)
  • We began this examination by comparison to the sigma factor gene set of B. subtilis . (biomedcentral.com)
  • Structure and function of bacterial sigma factors. (nih.gov)
  • The extracytoplasmic function (ECF) sigma factors are the largest and most diverse group of bacterial sigma factors. (harvard.edu)
  • In vitro assessment of S meliloti wild type and sigma factor mutants provided first evidence that the sigma factor RpoH1 plays a major role in the pH stress response. (beds.ac.uk)
  • It is homologous to archaeal transcription factor B and to eukaryotic TFIIB . (wikipedia.org)
  • Perinuclear organization of the transcription factor FoxM1 in malignant mesothelioma cells. (uvm.edu)
  • To study the function of sigma B genetically, we sought mutations that block the expression of a gene (ctc) known to be transcribed by sigma B-containing RNA polymerase in vitro. (asm.org)
  • To determine, which sigma factors are involved in recognition of particular promoters, we have developed the fi rst in vitro transcription system for C. glutamicum. (omicsonline.org)
  • In vitro transcription system may be particularly used for characterization of multiple promoters of diff erent classes and promoters recognized by two or more sigma factors. (omicsonline.org)
  • Surprisingly, nearly all of these sigma(D)-dependent promoters were also active to a much lower extent with sigma(H) in vivo and one (Pcg0607) also in vitro, although the known highly conserved consensus sequence of the sigma(H)-dependent promoters is different (-35 GGAA(T)/C and -10 GTT). (uni-bielefeld.de)
  • Other known sigma factors are of the σ54/RpoN (InterPro: IPR000394) type. (wikipedia.org)
  • Finally, we show that the RpoN σ factor decreases the basal expression of pilE when an activator is not present. (elsevier.com)
  • σ B is a non-essential primary-like σ factor that is present in C. glutamicum cells in the highest levels at the transition and in the early stationary phase (Larisch et al. (springeropen.com)
  • The role of TonB-dependent receptors and alternate sigma factors in the Bradyrhizobium japonicum/soybean symbiosis. (dartmouth.edu)
  • Mutation of the principal sigma factor causes loss of virulence in a strain of the Mycobacterium tuberculosis complex. (wikipathways.org)
  • Transcription is affected via the modulation of the concentrations of the different types of holoenzymes, so saturated promoters are only weakly affected by sigma factor competition. (mendeley.com)
  • Sigma factor competition is not strongly affected by non-specific binding of core RNAPs, sigma factors and holoenzymes to DNA. (mendeley.com)