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.
Genetic loci which direct transcription of ribosomal RNA in bacterial operons. They are designated rrnB, rrnC, rrnD, etc. according to the structural position of the transcription unit in the DNA sequence.
Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.
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.
The functional hereditary units of BACTERIA.
Proteins found in any species of bacterium.
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.
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.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
Proteins obtained from ESCHERICHIA COLI.
Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
A species of gram-positive bacteria that is a common soil and water saprophyte.
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.
Genes which regulate or circumscribe the activity of other genes; specifically, genes which code for PROTEINS or RNAs which have GENE EXPRESSION REGULATION functions.
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.
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.
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.
Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.
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.
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.
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.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
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.
A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.
Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.
A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)
Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.
Any method used for determining the location of and relative distances between genes on a chromosome.
A sequence of successive nucleotide triplets that are read as CODONS specifying AMINO ACIDS and begin with an INITIATOR CODON and end with a stop codon (CODON, TERMINATOR).
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 genetic complement of a BACTERIA as represented in its DNA.
The interference in synthesis of an enzyme due to the elevated level of an effector substance, usually a metabolite, whose presence would cause depression of the gene responsible for enzyme synthesis.
A protein which is a subunit of RNA polymerase. It effects initiation of specific RNA chains from DNA.
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
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 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.
DNA sequences recognized as signals to end GENETIC TRANSCRIPTION.
The regulatory elements of an OPERON to which activators or repressors bind thereby effecting the transcription of GENES in the operon.
Arabinose is a simple, pentose sugar (a monosaccharide with five carbon atoms) that is a constituent of various polysaccharides and glycosides, particularly found in plant tissues and some microorganisms, and can be metabolized in humans as a source of energy through the pentose phosphate pathway.
A species of gram-negative, aerobic bacteria isolated from soil and water as well as clinical specimens. Occasionally it is an opportunistic pathogen.
An enzyme that catalyzes the conversion of L-tryptophan and water to indole, pyruvate, and ammonia. It is a pyridoxal-phosphate protein, requiring K+. It also catalyzes 2,3-elimination and beta-replacement reactions of some indole-substituted tryptophan analogs of L-cysteine, L-serine, and other 3-substituted amino acids. (From Enzyme Nomenclature, 1992) EC 4.1.99.1.
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
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.
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.
The sequential location of genes on a chromosome.
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.
An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.
A LEUCINE and DNA-binding protein that is found primarily in BACTERIA and ARCHAEA. It regulates GENETIC TRANSCRIPTION involved in METABOLISM of AMINO ACIDS in response to the increased concentration of LEUCINE.
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).
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
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.
Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.
The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
A species of gram-negative, rod-shaped bacteria belonging to the K serogroup of ESCHERICHIA COLI. It lives as a harmless inhabitant of the human LARGE INTESTINE and is widely used in medical and GENETIC RESEARCH.
A disaccharide of GLUCOSE and GALACTOSE in human and cow milk. It is used in pharmacy for tablets, in medicine as a nutrient, and in industry.

Cloning and characterisation of a novel ompB operon from Vibrio cholerae 569B. (1/7987)

The ompB operon of Vibrio cholerae 569B has been cloned and fully sequenced. The operon encodes two proteins, OmpR and EnvZ, which share sequence identity with the OmpR and EnvZ proteins of a variety of other bacteria. Although the order of the ompR and envZ genes of V. cholerae is similar to that of the ompB operon of E. coli, S. typhimurium and X. nematophilus, the Vibrio operon exhibits a number of novel features. The structural organisation and features of the V. cholerae ompB operon are described.  (+info)

In vivo and in vitro processing of the Bacillus subtilis transcript coding for glutamyl-tRNA synthetase, serine acetyltransferase, and cysteinyl-tRNA synthetase. (2/7987)

In Bacillus subtilis, the adjacent genes gltX, cysE, and cysS encoding respectively glutamyl-tRNA synthetase, serine acetyl-transferase, and cysteinyl-tRNA synthetase, are transcribed as an operon but a gltX probe reveals only the presence of a monocistronic gltX mRNA (Gagnon et al., 1994, J Biol Chem 269:7473-7482). The transcript of the gltX-cysE intergenic region contains putative alternative secondary structures forming a p-independent terminator or an antiterminator, and a conserved sequence (T-box) found in the leader of most aminoacyl-tRNA synthetase and many amino acid biosynthesis genes in B. subtilis and in other Gram-positive eubacteria. The transcription of these genes is initiated 45 nt upstream from the first codon of gltX and is under the control of a sigmaA-type promoter. Analysis of the in vivo transcript of this operon revealed a cleavage site immediately downstream from the p-independent terminator structure. In vitro transcription analysis, using RNA polymerases from Escherichia coli, B. subtilis, and that encoded by the T7 phage, in the presence of various RNase inhibitors, shows the same cleavage. This processing generates mRNAs whose 5'-end half-lives differ by a factor of 2 in rich medium, and leaves putative secondary structures at the 3' end of the gltX transcript and at the 5' end of the cysE/S mRNA, which may be involved in the stabilization of these mRNAs. By its mechanism and its position, this cleavage differs from that of the other known transcripts encoding aminoacyl-tRNA synthetases in B. subtilis.  (+info)

A 55-kilodalton immunodominant antigen of Porphyromonas gingivalis W50 has arisen via horizontal gene transfer. (3/7987)

A 55-kDa outer membrane protein of Porphyromonas gingivalis W50 is a significant target of the serum immunoglobulin G antibody response of periodontal disease patients and hence may play an important role in host-bacterium interactions in periodontal disease. The gene encoding the 55-kDa antigen (ragB, for receptor antigen B) was isolated on a 9.5-kb partial Sau3AI fragment of P. gingivalis W50 chromosomal DNA in pUC18 by immunoscreening with a monoclonal antibody to this antigen. The 1.6-kb open reading frame (ORF) encoding RagB was located via subcloning and nested-deletion analysis. Sequence analysis demonstrated the presence of an upstream 3.1-kb ORF (ragA) which is cotranscribed with ragB. A number of genetic characteristics suggest that the ragAB locus was acquired by a horizontal gene transfer event. These include a significantly reduced G+C content relative to that of the P. gingivalis chromosome (42 versus 48%) and the presence of mobility elements flanking this locus in P. gingivalis W50. Furthermore, Southern blotting and PCR analyses showed a restricted distribution of this locus in laboratory and clinical isolates of this bacterium. The association of ragAB+ P. gingivalis with clinical status was examined by PCR analysis of subgingival samples. ragAB+ was not detected in P. gingivalis-positive shallow pockets from periodontal disease patients but was present in 36% of the P. gingivalis-positive samples from deep pockets. These data suggest that the ragAB locus was acquired by certain P. gingivalis strains via horizontal gene transfer and that the acquisition of this locus may facilitate the survival of these strains at sites of periodontal destruction.  (+info)

The virulence plasmid-encoded impCAB operon enhances survival and induced mutagenesis in Shigella flexneri after exposure to UV radiation. (4/7987)

Upon exposure to UV radiation, Shigella flexneri SA100 displayed survival and mutation frequencies comparable to those of Escherichia coli AB1157, which contains a functional UmuDC error-prone DNA repair system. Survival of SA100 after UV irradiation was associated with the presence of the 220-kb virulence plasmid, pVP. This plasmid encodes homologues of ImpA and ImpB, which comprise an error-prone DNA repair system encoded on plasmid TP110 that was initially identified in Salmonella typhimurium, and ImpC, encoded upstream of ImpA and ImpB. Although the impB gene was present in representatives of all four species of Shigella, not all isolates tested contained the gene. Shigella isolates that lacked impB were more sensitive to UV radiation than isolates that contained impB. The nucleotide sequence of a 2.4-kb DNA fragment containing the imp operon from S. flexneri SA100 pVP was 96% identical to the imp operon from the plasmid TP110. An SA100 derivative with a mutation in the impB gene had reduced survival following UV irradiation and less UV-induced mutagenesis relative to the parental strain. We also found that S. flexneri contained a chromosomally encoded umuDC operon; however, the umuDC promoter was not induced by exposure to UV radiation. This suggests that the imp operon but not the umuDC operon contributes to survival and induced mutagenesis in S. flexneri following exposure to UV radiation.  (+info)

A novel reduced flavin mononucleotide-dependent methanesulfonate sulfonatase encoded by the sulfur-regulated msu operon of Pseudomonas aeruginosa. (5/7987)

When Pseudomonas aeruginosa is grown with organosulfur compounds as sulfur sources, it synthesizes a set of proteins whose synthesis is repressed in the presence of sulfate, cysteine, or thiocyanate (so-called sulfate starvation-induced proteins). The gene encoding one of these proteins, PA13, was isolated from a cosmid library of P. aeruginosa PAO1 and sequenced. It encoded a 381-amino-acid protein that was related to several reduced flavin mononucleotide (FMNH2)-dependent monooxygenases, and it was the second in an operon of three genes, which we have named msuEDC. The MsuD protein catalyzed the desulfonation of alkanesulfonates, requiring oxygen and FMNH2 for the reaction, and showed highest activity with methanesulfonate. MsuE was an NADH-dependent flavin mononucleotide (FMN) reductase, which provided reduced FMN for the MsuD enzyme. Expression of the msu operon was analyzed with a transcriptional msuD::xylE fusion and was found to be repressed in the presence of sulfate, sulfite, sulfide, or cysteine and derepressed during growth with methionine or alkanesulfonates. Growth with methanesulfonate required an intact cysB gene, and the msu operon is therefore part of the cys regulon, since sulfite utilization was found to be CysB independent in this species. Measurements of msuD::xylE expression in cysN and cysI genetic backgrounds showed that sulfate, sulfite, and sulfide or cysteine play independent roles in negatively regulating msu expression, and sulfonate utilization therefore appears to be tightly regulated.  (+info)

An Lrp-like protein of the hyperthermophilic archaeon Sulfolobus solfataricus which binds to its own promoter. (6/7987)

Regulation of gene expression in the domain Archaea, and specifically hyperthermophiles, has been poorly investigated so far. Biochemical experiments and genome sequencing have shown that, despite the prokaryotic cell and genome organization, basal transcriptional elements of members of the domain Archaea (i.e., TATA box-like sequences, RNA polymerase, and transcription factors TBP, TFIIB, and TFIIS) are of the eukaryotic type. However, open reading frames potentially coding for bacterium-type transcription regulation factors have been recognized in different archaeal strains. This finding raises the question of how bacterial and eukaryotic elements interact in regulating gene expression in Archaea. We have identified a gene coding for a bacterium-type transcription factor in the hyperthermophilic archaeon Sulfolobus solfataricus. The protein, named Lrs14, contains a potential helix-turn-helix motif and is related to the Lrp-AsnC family of regulators of gene expression in the class Bacteria. We show that Lrs14, expressed in Escherichia coli, is a highly thermostable DNA-binding protein. Bandshift and DNase I footprint analyses show that Lrs14 specifically binds to multiple sequences in its own promoter and that the region of binding overlaps the TATA box, suggesting that, like the E. coli Lrp, Lrs14 is autoregulated. We also show that the lrs14 transcript is accumulated in the late growth stages of S. solfataricus.  (+info)

Molecular characterization of the nitrite-reducing system of Staphylococcus carnosus. (7/7987)

Characterization of a nitrite reductase-negative Staphylococcus carnosus Tn917 mutant led to the identification of the nir operon, which encodes NirBD, the dissimilatory NADH-dependent nitrite reductase; SirA, the putative oxidase and chelatase, and SirB, the uroporphyrinogen III methylase, both of which are necessary for biosynthesis of the siroheme prosthetic group; and NirR, which revealed no convincing similarity to proteins with known functions. We suggest that NirR is essential for nir promoter activity. In the absence of NirR, a weak promoter upstream of sirA seems to drive transcription of sirA, nirB, nirD, and sirB in the stationary-growth phase. In primer extension experiments one predominant and several weaker transcription start sites were identified in the nir promoter region. Northern blot analyses indicated that anaerobiosis and nitrite are induction factors of the nir operon: cells grown aerobically with nitrite revealed small amounts of full-length transcript whereas cells grown anaerobically with or without nitrite showed large amounts of full-length transcript. Although a transcript is detectable, no nitrite reduction occurs in cells grown aerobically with nitrite, indicating an additional oxygen-controlled step at the level of translation, enzyme folding, assembly, or insertion of prosthetic groups. The nitrite-reducing activity expressed during anaerobiosis is switched off reversibly when the oxygen tension increases, most likely due to competition for electrons with the aerobic respiratory chain. Another gene, nirC, is located upstream of the nir operon. nirC encodes a putative integral membrane-spanning protein of unknown function. A nirC mutant showed no distinct phenotype.  (+info)

Role of ribosome release in regulation of tna operon expression in Escherichia coli. (8/7987)

Expression of the degradative tryptophanase (tna) operon of Escherichia coli is regulated by catabolite repression and tryptophan-induced transcription antitermination. In cultures growing in the absence of added tryptophan, transcription of the structural genes of the tna operon is limited by Rho-dependent transcription termination in the leader region of the operon. Tryptophan induction prevents this Rho-dependent termination, and requires in-frame translation of a 24-residue leader peptide coding region, tnaC, that contains a single, crucial, Trp codon. Studies with a lacZ reporter construct lacking the spacer region between tnaC and the first major structural gene, tnaA, suggested that tryptophan induction might involve cis action by the TnaC leader peptide on the ribosome translating the tnaC coding region. The leader peptide was hypothesized to inhibit ribosome release at the tnaC stop codon, thereby blocking Rho's access to the transcript. Regulatory studies with deletion constructs of the tna operon of Proteus vulgaris supported this interpretation. In the present study the putative role of the tnaC stop codon in tna operon regulation in E. coli was examined further by replacing the natural tnaC stop codon, UGA, with UAG or UAA in a tnaC-stop codon-tnaA'-'lacZ reporter construct. Basal level expression was reduced to 20 and 50% when the UGA stop codon was replaced by UAG or UAA, respectively, consistent with the finding that in E. coli translation terminates more efficiently at UAG and UAA than at UGA. Tryptophan induction was observed in strains with any of the stop codons. However, when UAG or UAA replaced UGA, the induced level of expression was also reduced to 15 and 50% of that obtained with UGA as the tnaC stop codon, respectively. Introduction of a mutant allele encoding a temperature-sensitive release factor 1, prfA1, increased basal level expression 60-fold when the tnaC stop codon was UAG and 3-fold when this stop codon was UAA; basal level expression was reduced by 50% in the construct with the natural stop codon, UGA. In strains with any of the three stop codons and the prfA1 mutation, the induced levels of tna operon expression were virtually identical. The effects of tnaC stop codon identity on expression were also examined in the absence of Rho action, using tnaC-stop codon-'lacZ constructs that lack the tnaC-tnaA spacer region. Expression was low in the absence of tnaC stop codon suppression. In most cases, tryptophan addition resulted in about 50% inhibition of expression when UGA was replaced by UAG or UAA and the appropriate suppressor was present. Introduction of the prfA1 mutant allele increased expression of the suppressed construct with the UAG stop codon; tryptophan addition also resulted in ca. 50% inhibition. These findings provide additional evidence implicating the behavior of the ribosome translating tnaC in the regulation of tna operon expression.  (+info)

An operon is a genetic unit in prokaryotic organisms (like bacteria) consisting of a cluster of genes that are transcribed together as a single mRNA molecule, which then undergoes translation to produce multiple proteins. This genetic organization allows for the coordinated regulation of genes that are involved in the same metabolic pathway or functional process. The unit typically includes promoter and operator regions that control the transcription of the operon, as well as structural genes encoding the proteins. Operons were first discovered in bacteria, but similar genetic organizations have been found in some eukaryotic organisms, such as yeast.

I'm sorry for any confusion, but "rRNA operon" is not a standard medical term. However, in the field of molecular biology, an operon refers to a genetic unit that consists of an operator, promoter, and structurgenes that are transcribed together as a single mRNA molecule. In bacteria, several rRNA genes (16S, 23S, and 5S) are often found organized in this way, forming what is called an rRNA operon or a ribosomal RNA operon.

The rRNA operon contains multiple copies of the genes that encode for the three types of rRNA molecules (16S, 23S, and 5S) that are essential components of the bacterial ribosome. These genes are transcribed together as a single large precursor RNA, which is then processed to yield the individual rRNA molecules.

While "rRNA operon" may not be a standard term in medical textbooks, it is an important concept in molecular biology and genetics, particularly in the study of bacterial gene expression and ribosome synthesis.

Gene expression regulation in bacteria refers to the complex cellular processes that control the production of proteins from specific genes. This regulation allows bacteria to adapt to changing environmental conditions and ensure the appropriate amount of protein is produced at the right time.

Bacteria have a variety of mechanisms for regulating gene expression, including:

1. Operon structure: Many bacterial genes are organized into operons, which are clusters of genes that are transcribed together as a single mRNA molecule. The expression of these genes can be coordinately regulated by controlling the transcription of the entire operon.
2. Promoter regulation: Transcription is initiated at promoter regions upstream of the gene or operon. Bacteria have regulatory proteins called sigma factors that bind to the promoter and recruit RNA polymerase, the enzyme responsible for transcribing DNA into RNA. The binding of sigma factors can be influenced by environmental signals, allowing for regulation of transcription.
3. Attenuation: Some operons have regulatory regions called attenuators that control transcription termination. These regions contain hairpin structures that can form in the mRNA and cause transcription to stop prematurely. The formation of these hairpins is influenced by the concentration of specific metabolites, allowing for regulation of gene expression based on the availability of those metabolites.
4. Riboswitches: Some bacterial mRNAs contain regulatory elements called riboswitches that bind small molecules directly. When a small molecule binds to the riboswitch, it changes conformation and affects transcription or translation of the associated gene.
5. CRISPR-Cas systems: Bacteria use CRISPR-Cas systems for adaptive immunity against viruses and plasmids. These systems incorporate short sequences from foreign DNA into their own genome, which can then be used to recognize and cleave similar sequences in invading genetic elements.

Overall, gene expression regulation in bacteria is a complex process that allows them to respond quickly and efficiently to changing environmental conditions. Understanding these regulatory mechanisms can provide insights into bacterial physiology and help inform strategies for controlling bacterial growth and behavior.

The lac operon is a genetic regulatory system found in the bacteria Escherichia coli that controls the expression of genes responsible for the metabolism of lactose as a source of energy. It consists of three structural genes (lacZ, lacY, and lacA) that code for enzymes involved in lactose metabolism, as well as two regulatory elements: the lac promoter and the lac operator.

The lac repressor protein, produced by the lacI gene, binds to the lac operator sequence when lactose is not present, preventing RNA polymerase from transcribing the structural genes. When lactose is available, it is converted into allolactose, which acts as an inducer and binds to the lac repressor protein, causing a conformational change that prevents it from binding to the operator sequence. This allows RNA polymerase to bind to the promoter and transcribe the structural genes, leading to the production of enzymes necessary for lactose metabolism.

In summary, the lac operon is a genetic regulatory system in E. coli that controls the expression of genes involved in lactose metabolism based on the availability of lactose as a substrate.

A bacterial gene is a segment of DNA (or RNA in some viruses) that contains the genetic information necessary for the synthesis of a functional bacterial protein or RNA molecule. These genes are responsible for encoding various characteristics and functions of bacteria such as metabolism, reproduction, and resistance to antibiotics. They can be transmitted between bacteria through horizontal gene transfer mechanisms like conjugation, transformation, and transduction. Bacterial genes are often organized into operons, which are clusters of genes that are transcribed together as a single mRNA molecule.

It's important to note that the term "bacterial gene" is used to describe genetic elements found in bacteria, but not all genetic elements in bacteria are considered genes. For example, some DNA sequences may not encode functional products and are therefore not considered genes. Additionally, some bacterial genes may be plasmid-borne or phage-borne, rather than being located on the bacterial chromosome.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

Genetic transcription is the process by which the information in a strand of DNA is used to create a complementary RNA molecule. This process is the first step in gene expression, where the genetic code in DNA is converted into a form that can be used to produce proteins or functional RNAs.

During transcription, an enzyme called RNA polymerase binds to the DNA template strand and reads the sequence of nucleotide bases. As it moves along the template, it adds complementary RNA nucleotides to the growing RNA chain, creating a single-stranded RNA molecule that is complementary to the DNA template strand. Once transcription is complete, the RNA molecule may undergo further processing before it can be translated into protein or perform its functional role in the cell.

Transcription can be either "constitutive" or "regulated." Constitutive transcription occurs at a relatively constant rate and produces essential proteins that are required for basic cellular functions. Regulated transcription, on the other hand, is subject to control by various intracellular and extracellular signals, allowing cells to respond to changing environmental conditions or developmental cues.

Bacterial DNA refers to the genetic material found in bacteria. It is composed of a double-stranded helix containing four nucleotide bases - adenine (A), thymine (T), guanine (G), and cytosine (C) - that are linked together by phosphodiester bonds. The sequence of these bases in the DNA molecule carries the genetic information necessary for the growth, development, and reproduction of bacteria.

Bacterial DNA is circular in most bacterial species, although some have linear chromosomes. In addition to the main chromosome, many bacteria also contain small circular pieces of DNA called plasmids that can carry additional genes and provide resistance to antibiotics or other environmental stressors.

Unlike eukaryotic cells, which have their DNA enclosed within a nucleus, bacterial DNA is present in the cytoplasm of the cell, where it is in direct contact with the cell's metabolic machinery. This allows for rapid gene expression and regulation in response to changing environmental conditions.

'Escherichia coli (E. coli) proteins' refer to the various types of proteins that are produced and expressed by the bacterium Escherichia coli. These proteins play a critical role in the growth, development, and survival of the organism. They are involved in various cellular processes such as metabolism, DNA replication, transcription, translation, repair, and regulation.

E. coli is a gram-negative, facultative anaerobe that is commonly found in the intestines of warm-blooded organisms. It is widely used as a model organism in scientific research due to its well-studied genetics, rapid growth, and ability to be easily manipulated in the laboratory. As a result, many E. coli proteins have been identified, characterized, and studied in great detail.

Some examples of E. coli proteins include enzymes involved in carbohydrate metabolism such as lactase, sucrase, and maltose; proteins involved in DNA replication such as the polymerases, single-stranded binding proteins, and helicases; proteins involved in transcription such as RNA polymerase and sigma factors; proteins involved in translation such as ribosomal proteins, tRNAs, and aminoacyl-tRNA synthetases; and regulatory proteins such as global regulators, two-component systems, and transcription factors.

Understanding the structure, function, and regulation of E. coli proteins is essential for understanding the basic biology of this important organism, as well as for developing new strategies for combating bacterial infections and improving industrial processes involving bacteria.

Bacterial RNA refers to the genetic material present in bacteria that is composed of ribonucleic acid (RNA). Unlike higher organisms, bacteria contain a single circular chromosome made up of DNA, along with smaller circular pieces of DNA called plasmids. These bacterial genetic materials contain the information necessary for the growth and reproduction of the organism.

Bacterial RNA can be divided into three main categories: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). mRNA carries genetic information copied from DNA, which is then translated into proteins by the rRNA and tRNA molecules. rRNA is a structural component of the ribosome, where protein synthesis occurs, while tRNA acts as an adapter that brings amino acids to the ribosome during protein synthesis.

Bacterial RNA plays a crucial role in various cellular processes, including gene expression, protein synthesis, and regulation of metabolic pathways. Understanding the structure and function of bacterial RNA is essential for developing new antibiotics and other therapeutic strategies to combat bacterial infections.

'Bacillus subtilis' is a gram-positive, rod-shaped bacterium that is commonly found in soil and vegetation. It is a facultative anaerobe, meaning it can grow with or without oxygen. This bacterium is known for its ability to form durable endospores during unfavorable conditions, which allows it to survive in harsh environments for long periods of time.

'Bacillus subtilis' has been widely studied as a model organism in microbiology and molecular biology due to its genetic tractability and rapid growth. It is also used in various industrial applications, such as the production of enzymes, antibiotics, and other bioproducts.

Although 'Bacillus subtilis' is generally considered non-pathogenic, there have been rare cases of infection in immunocompromised individuals. It is important to note that this bacterium should not be confused with other pathogenic species within the genus Bacillus, such as B. anthracis (causative agent of anthrax) or B. cereus (a foodborne pathogen).

Promoter regions in genetics refer to specific DNA sequences located near the transcription start site of a gene. They serve as binding sites for RNA polymerase and various transcription factors that regulate the initiation of gene transcription. These regulatory elements help control the rate of transcription and, therefore, the level of gene expression. Promoter regions can be composed of different types of sequences, such as the TATA box and CAAT box, and their organization and composition can vary between different genes and species.

Regulator genes are a type of gene that regulates the activity of other genes in an organism. They do not code for a specific protein product but instead control the expression of other genes by producing regulatory proteins such as transcription factors, repressors, or enhancers. These regulatory proteins bind to specific DNA sequences near the target genes and either promote or inhibit their transcription into mRNA. This allows regulator genes to play a crucial role in coordinating complex biological processes, including development, differentiation, metabolism, and response to environmental stimuli.

There are several types of regulator genes, including:

1. Constitutive regulators: These genes are always active and produce regulatory proteins that control the expression of other genes in a consistent manner.
2. Inducible regulators: These genes respond to specific signals or environmental stimuli by producing regulatory proteins that modulate the expression of target genes.
3. Negative regulators: These genes produce repressor proteins that bind to DNA and inhibit the transcription of target genes, thereby reducing their expression.
4. Positive regulators: These genes produce activator proteins that bind to DNA and promote the transcription of target genes, thereby increasing their expression.
5. Master regulators: These genes control the expression of multiple downstream target genes involved in specific biological processes or developmental pathways.

Regulator genes are essential for maintaining proper gene expression patterns and ensuring normal cellular function. Mutations in regulator genes can lead to various diseases, including cancer, developmental disorders, and metabolic dysfunctions.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Restriction mapping is a technique used in molecular biology to identify the location and arrangement of specific restriction endonuclease recognition sites within a DNA molecule. Restriction endonucleases are enzymes that cut double-stranded DNA at specific sequences, producing fragments of various lengths. By digesting the DNA with different combinations of these enzymes and analyzing the resulting fragment sizes through techniques such as agarose gel electrophoresis, researchers can generate a restriction map - a visual representation of the locations and distances between recognition sites on the DNA molecule. This information is crucial for various applications, including cloning, genome analysis, and genetic engineering.

A genetic complementation test is a laboratory procedure used in molecular genetics to determine whether two mutated genes can complement each other's function, indicating that they are located at different loci and represent separate alleles. This test involves introducing a normal or wild-type copy of one gene into a cell containing a mutant version of the same gene, and then observing whether the presence of the normal gene restores the normal function of the mutated gene. If the introduction of the normal gene results in the restoration of the normal phenotype, it suggests that the two genes are located at different loci and can complement each other's function. However, if the introduction of the normal gene does not restore the normal phenotype, it suggests that the two genes are located at the same locus and represent different alleles of the same gene. This test is commonly used to map genes and identify genetic interactions in a variety of organisms, including bacteria, yeast, and animals.

Repressor proteins are a type of regulatory protein in molecular biology that suppress the transcription of specific genes into messenger RNA (mRNA) by binding to DNA. They function as part of gene regulation processes, often working in conjunction with an operator region and a promoter region within the DNA molecule. Repressor proteins can be activated or deactivated by various signals, allowing for precise control over gene expression in response to changing cellular conditions.

There are two main types of repressor proteins:

1. DNA-binding repressors: These directly bind to specific DNA sequences (operator regions) near the target gene and prevent RNA polymerase from transcribing the gene into mRNA.
2. Allosteric repressors: These bind to effector molecules, which then cause a conformational change in the repressor protein, enabling it to bind to DNA and inhibit transcription.

Repressor proteins play crucial roles in various biological processes, such as development, metabolism, and stress response, by controlling gene expression patterns in cells.

Insertional mutagenesis is a process of introducing new genetic material into an organism's genome at a specific location, which can result in a change or disruption of the function of the gene at that site. This technique is often used in molecular biology research to study gene function and regulation. The introduction of the foreign DNA is typically accomplished through the use of mobile genetic elements, such as transposons or viruses, which are capable of inserting themselves into the genome.

The insertion of the new genetic material can lead to a loss or gain of function in the affected gene, resulting in a mutation. This type of mutagenesis is called "insertional" because the mutation is caused by the insertion of foreign DNA into the genome. The effects of insertional mutagenesis can range from subtle changes in gene expression to the complete inactivation of a gene.

This technique has been widely used in genetic research, including the study of developmental biology, cancer, and genetic diseases. It is also used in the development of genetically modified organisms (GMOs) for agricultural and industrial applications.

DNA Sequence Analysis is the systematic determination of the order of nucleotides in a DNA molecule. It is a critical component of modern molecular biology, genetics, and genetic engineering. The process involves determining the exact order of the four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - in a DNA molecule or fragment. This information is used in various applications such as identifying gene mutations, studying evolutionary relationships, developing molecular markers for breeding, and diagnosing genetic diseases.

The process of DNA Sequence Analysis typically involves several steps, including DNA extraction, PCR amplification (if necessary), purification, sequencing reaction, and electrophoresis. The resulting data is then analyzed using specialized software to determine the exact sequence of nucleotides.

In recent years, high-throughput DNA sequencing technologies have revolutionized the field of genomics, enabling the rapid and cost-effective sequencing of entire genomes. This has led to an explosion of genomic data and new insights into the genetic basis of many diseases and traits.

Beta-galactosidase is an enzyme that catalyzes the hydrolysis of beta-galactosides into monosaccharides. It is found in various organisms, including bacteria, yeast, and mammals. In humans, it plays a role in the breakdown and absorption of certain complex carbohydrates, such as lactose, in the small intestine. Deficiency of this enzyme in humans can lead to a disorder called lactose intolerance. In scientific research, beta-galactosidase is often used as a marker for gene expression and protein localization studies.

"Salmonella enterica" serovar "Typhimurium" is a subspecies of the bacterial species Salmonella enterica, which is a gram-negative, facultatively anaerobic, rod-shaped bacterium. It is a common cause of foodborne illness in humans and animals worldwide. The bacteria can be found in a variety of sources, including contaminated food and water, raw meat, poultry, eggs, and dairy products.

The infection caused by Salmonella Typhimurium is typically self-limiting and results in gastroenteritis, which is characterized by symptoms such as diarrhea, abdominal cramps, fever, and vomiting. However, in some cases, the infection can spread to other parts of the body and cause more severe illness, particularly in young children, older adults, and people with weakened immune systems.

Salmonella Typhimurium is a major public health concern due to its ability to cause outbreaks of foodborne illness, as well as its potential to develop antibiotic resistance. Proper food handling, preparation, and storage practices can help prevent the spread of Salmonella Typhimurium and other foodborne pathogens.

Bacterial chromosomes are typically circular, double-stranded DNA molecules that contain the genetic material of bacteria. Unlike eukaryotic cells, which have their DNA housed within a nucleus, bacterial chromosomes are located in the cytoplasm of the cell, often associated with the bacterial nucleoid.

Bacterial chromosomes can vary in size and structure among different species, but they typically contain all of the genetic information necessary for the survival and reproduction of the organism. They may also contain plasmids, which are smaller circular DNA molecules that can carry additional genes and can be transferred between bacteria through a process called conjugation.

One important feature of bacterial chromosomes is their ability to replicate rapidly, allowing bacteria to divide quickly and reproduce in large numbers. The replication of the bacterial chromosome begins at a specific origin point and proceeds in opposite directions until the entire chromosome has been copied. This process is tightly regulated and coordinated with cell division to ensure that each daughter cell receives a complete copy of the genetic material.

Overall, the study of bacterial chromosomes is an important area of research in microbiology, as understanding their structure and function can provide insights into bacterial genetics, evolution, and pathogenesis.

A multigene family is a group of genetically related genes that share a common ancestry and have similar sequences or structures. These genes are arranged in clusters on a chromosome and often encode proteins with similar functions. They can arise through various mechanisms, including gene duplication, recombination, and transposition. Multigene families play crucial roles in many biological processes, such as development, immunity, and metabolism. Examples of multigene families include the globin genes involved in oxygen transport, the immune system's major histocompatibility complex (MHC) genes, and the cytochrome P450 genes associated with drug metabolism.

DNA transposable elements, also known as transposons or jumping genes, are mobile genetic elements that can change their position within a genome. They are composed of DNA sequences that include genes encoding the enzymes required for their own movement (transposase) and regulatory elements. When activated, the transposase recognizes specific sequences at the ends of the element and catalyzes the excision and reintegration of the transposable element into a new location in the genome. This process can lead to genetic variation, as the insertion of a transposable element can disrupt the function of nearby genes or create new combinations of gene regulatory elements. Transposable elements are widespread in both prokaryotic and eukaryotic genomes and are thought to play a significant role in genome evolution.

Chromosome mapping, also known as physical mapping, is the process of determining the location and order of specific genes or genetic markers on a chromosome. This is typically done by using various laboratory techniques to identify landmarks along the chromosome, such as restriction enzyme cutting sites or patterns of DNA sequence repeats. The resulting map provides important information about the organization and structure of the genome, and can be used for a variety of purposes, including identifying the location of genes associated with genetic diseases, studying evolutionary relationships between organisms, and developing genetic markers for use in breeding or forensic applications.

An open reading frame (ORF) is a continuous stretch of DNA or RNA sequence that has the potential to be translated into a protein. It begins with a start codon (usually "ATG" in DNA, which corresponds to "AUG" in RNA) and ends with a stop codon ("TAA", "TAG", or "TGA" in DNA; "UAA", "UAG", or "UGA" in RNA). The sequence between these two points is called a coding sequence (CDS), which, when transcribed into mRNA and translated into amino acids, forms a polypeptide chain.

In eukaryotic cells, ORFs can be located in either protein-coding genes or non-coding regions of the genome. In prokaryotic cells, multiple ORFs may be present on a single strand of DNA, often organized into operons that are transcribed together as a single mRNA molecule.

It's important to note that not all ORFs necessarily represent functional proteins; some may be pseudogenes or result from errors in genome annotation. Therefore, additional experimental evidence is typically required to confirm the expression and functionality of a given ORF.

A regulon is a group of genes that are regulated together in response to a specific signal or stimulus, often through the action of a single transcription factor or regulatory protein. This means that when the transcription factor binds to specific DNA sequences called operators, it can either activate or repress the transcription of all the genes within the regulon.

This type of gene regulation is important for coordinating complex biological processes, such as cellular metabolism, stress responses, and developmental programs. By regulating a group of genes together, cells can ensure that they are all turned on or off in a coordinated manner, allowing for more precise control over the overall response to a given signal.

It's worth noting that the term "regulon" is not commonly used in clinical medicine, but rather in molecular biology and genetics research.

A bacterial genome is the complete set of genetic material, including both DNA and RNA, found within a single bacterium. It contains all the hereditary information necessary for the bacterium to grow, reproduce, and survive in its environment. The bacterial genome typically includes circular chromosomes, as well as plasmids, which are smaller, circular DNA molecules that can carry additional genes. These genes encode various functional elements such as enzymes, structural proteins, and regulatory sequences that determine the bacterium's characteristics and behavior.

Bacterial genomes vary widely in size, ranging from around 130 kilobases (kb) in Mycoplasma genitalium to over 14 megabases (Mb) in Sorangium cellulosum. The complete sequencing and analysis of bacterial genomes have provided valuable insights into the biology, evolution, and pathogenicity of bacteria, enabling researchers to better understand their roles in various diseases and potential applications in biotechnology.

Enzyme repression is a type of gene regulation in which the production of an enzyme is inhibited or suppressed, thereby reducing the rate of catalysis of the chemical reaction that the enzyme facilitates. This process typically occurs when the end product of the reaction binds to the regulatory protein, called a repressor, which then binds to the operator region of the operon (a group of genes that are transcribed together) and prevents transcription of the structural genes encoding for the enzyme. Enzyme repression helps maintain homeostasis within the cell by preventing the unnecessary production of enzymes when they are not needed, thus conserving energy and resources.

A sigma factor is a type of protein in bacteria that plays an essential role in the initiation of transcription, which is the first step of gene expression. Sigma factors recognize and bind to specific sequences on DNA, known as promoters, enabling the attachment of RNA polymerase, the enzyme responsible for synthesizing RNA.

In bacteria, RNA polymerase is made up of several subunits, including a core enzyme and a sigma factor. The sigma factor confers specificity to the RNA polymerase by recognizing and binding to the promoter region of the DNA, allowing transcription to begin. Once transcription starts, the sigma factor is released from the RNA polymerase, which then continues to synthesize RNA until it reaches the end of the gene.

Bacteria have multiple sigma factors that allow them to respond to different environmental conditions and stresses by regulating the expression of specific sets of genes. For example, some sigma factors are involved in the regulation of genes required for growth and metabolism under normal conditions, while others are involved in the response to heat shock, starvation, or other stressors.

Overall, sigma factors play a crucial role in regulating gene expression in bacteria, allowing them to adapt to changing environmental conditions and maintain cellular homeostasis.

A gene is a specific sequence of nucleotides in DNA that carries genetic information. Genes are the fundamental units of heredity and are responsible for the development and function of all living organisms. They code for proteins or RNA molecules, which carry out various functions within cells and are essential for the structure, function, and regulation of the body's tissues and organs.

Each gene has a specific location on a chromosome, and each person inherits two copies of every gene, one from each parent. Variations in the sequence of nucleotides in a gene can lead to differences in traits between individuals, including physical characteristics, susceptibility to disease, and responses to environmental factors.

Medical genetics is the study of genes and their role in health and disease. It involves understanding how genes contribute to the development and progression of various medical conditions, as well as identifying genetic risk factors and developing strategies for prevention, diagnosis, and treatment.

Sequence homology, amino acid, refers to the similarity in the order of amino acids in a protein or a portion of a protein between two or more species. This similarity can be used to infer evolutionary relationships and functional similarities between proteins. The higher the degree of sequence homology, the more likely it is that the proteins are related and have similar functions. Sequence homology can be determined through various methods such as pairwise alignment or multiple sequence alignment, which compare the sequences and calculate a score based on the number and type of matching amino acids.

Artificial gene fusion refers to the creation of a new gene by joining together parts or whole sequences from two or more different genes. This is achieved through genetic engineering techniques, where the DNA segments are cut and pasted using enzymes called restriction endonucleases and ligases. The resulting artificial gene may encode for a novel protein with unique functions that neither of the parental genes possess. This approach has been widely used in biomedical research to study gene function, create new diagnostic tools, and develop gene therapies.

Sequence homology in nucleic acids refers to the similarity or identity between the nucleotide sequences of two or more DNA or RNA molecules. It is often used as a measure of biological relationship between genes, organisms, or populations. High sequence homology suggests a recent common ancestry or functional constraint, while low sequence homology may indicate a more distant relationship or different functions.

Nucleic acid sequence homology can be determined by various methods such as pairwise alignment, multiple sequence alignment, and statistical analysis. The degree of homology is typically expressed as a percentage of identical or similar nucleotides in a given window of comparison.

It's important to note that the interpretation of sequence homology depends on the biological context and the evolutionary distance between the sequences compared. Therefore, functional and experimental validation is often necessary to confirm the significance of sequence homology.

"Terminator regions" is a term used in molecular biology and genetics to describe specific sequences within DNA that control the termination of transcription, which is the process of creating an RNA copy of a sequence of DNA. These regions are also sometimes referred to as "transcription termination sites."

In the context of genetic terminators, the term "terminator" refers to the sequence of nucleotides that signals the end of the gene and the beginning of the termination process. The terminator region typically contains a specific sequence of nucleotides that recruits proteins called termination factors, which help to disrupt the transcription bubble and release the newly synthesized RNA molecule from the DNA template.

It's important to note that there are different types of terminators in genetics, including "Rho-dependent" and "Rho-independent" terminators, which differ in their mechanisms for terminating transcription. Rho-dependent terminators rely on the action of a protein called Rho, while Rho-independent terminators form a stable hairpin structure that causes the transcription machinery to stall and release the RNA.

In summary, "Terminator regions" in genetics are specific sequences within DNA that control the termination of transcription by signaling the end of the gene and recruiting proteins or forming structures that disrupt the transcription bubble and release the newly synthesized RNA molecule.

Operator regions in genetics refer to specific DNA sequences that regulate the transcription of nearby genes. These regions are binding sites for proteins called transcription factors, which control the rate at which genetic information is copied into RNA. Operator regions are typically located near the promoter region of a gene and can influence the expression of one or multiple genes in a coordinated manner.

In some cases, operator regions may be shared by several genes that are organized into a single operon, a genetic unit consisting of a cluster of genes that are transcribed together as a single mRNA molecule. Operators play a crucial role in the regulation of gene expression and help to ensure that genes are turned on or off at appropriate times during development and in response to environmental signals.

Arabinose is a simple sugar or monosaccharide that is a stereoisomer of xylose. It is a pentose, meaning it contains five carbon atoms, and is classified as a hexahydroxyhexital because it has six hydroxyl (-OH) groups attached to the carbon atoms. Arabinose is found in various plant polysaccharides, such as hemicelluloses, gums, and pectic substances. It can also be found in some bacteria and yeasts, where it plays a role in their metabolism. In humans, arabinose is not an essential nutrient and must be metabolized by specific enzymes if consumed.

"Pseudomonas putida" is a species of gram-negative, rod-shaped bacteria that is commonly found in soil and water environments. It is a non-pathogenic, opportunistic microorganism that is known for its versatile metabolism and ability to degrade various organic compounds. This bacterium has been widely studied for its potential applications in bioremediation and industrial biotechnology due to its ability to break down pollutants such as toluene, xylene, and other aromatic hydrocarbons. It is also known for its resistance to heavy metals and antibiotics, making it a valuable tool in the study of bacterial survival mechanisms and potential applications in bioremediation and waste treatment.

Tryptophanase is not a medical term per se, but rather a biochemical term used to describe an enzyme. However, I can provide a biochemical definition for you:

Tryptophanase (TPase or TnaA) is a pyridoxal-phosphate (PLP) dependent enzyme found in certain bacteria, such as Escherichia coli, that catalyzes the breakdown of the essential amino acid tryptophan into several compounds. The primary reaction catalyzed by tryptophanase is the conversion of L-tryptophan to indole, pyruvate, and ammonia. This reaction also produces ATP and ADP as co-products.

The production of indole from tryptophan by tryptophanase has diagnostic value in microbiology, as the presence of indole in a culture medium can indicate the growth of certain bacterial species that produce this enzyme.

Transcription factors are proteins that play a crucial role in regulating gene expression by controlling the transcription of DNA to messenger RNA (mRNA). They function by binding to specific DNA sequences, known as response elements, located in the promoter region or enhancer regions of target genes. This binding can either activate or repress the initiation of transcription, depending on the properties and interactions of the particular transcription factor. Transcription factors often act as part of a complex network of regulatory proteins that determine the precise spatiotemporal patterns of gene expression during development, differentiation, and homeostasis in an organism.

Gene deletion is a type of mutation where a segment of DNA, containing one or more genes, is permanently lost or removed from a chromosome. This can occur due to various genetic mechanisms such as homologous recombination, non-homologous end joining, or other types of genomic rearrangements.

The deletion of a gene can have varying effects on the organism, depending on the function of the deleted gene and its importance for normal physiological processes. If the deleted gene is essential for survival, the deletion may result in embryonic lethality or developmental abnormalities. However, if the gene is non-essential or has redundant functions, the deletion may not have any noticeable effects on the organism's phenotype.

Gene deletions can also be used as a tool in genetic research to study the function of specific genes and their role in various biological processes. For example, researchers may use gene deletion techniques to create genetically modified animal models to investigate the impact of gene deletion on disease progression or development.

DNA-binding proteins are a type of protein that have the ability to bind to DNA (deoxyribonucleic acid), the genetic material of organisms. These proteins play crucial roles in various biological processes, such as regulation of gene expression, DNA replication, repair and recombination.

The binding of DNA-binding proteins to specific DNA sequences is mediated by non-covalent interactions, including electrostatic, hydrogen bonding, and van der Waals forces. The specificity of binding is determined by the recognition of particular nucleotide sequences or structural features of the DNA molecule.

DNA-binding proteins can be classified into several categories based on their structure and function, such as transcription factors, histones, and restriction enzymes. Transcription factors are a major class of DNA-binding proteins that regulate gene expression by binding to specific DNA sequences in the promoter region of genes and recruiting other proteins to modulate transcription. Histones are DNA-binding proteins that package DNA into nucleosomes, the basic unit of chromatin structure. Restriction enzymes are DNA-binding proteins that recognize and cleave specific DNA sequences, and are widely used in molecular biology research and biotechnology applications.

Gene order, in the context of genetics and genomics, refers to the specific sequence or arrangement of genes along a chromosome. The order of genes on a chromosome is not random, but rather, it is highly conserved across species and is often used as a tool for studying evolutionary relationships between organisms.

The study of gene order has also provided valuable insights into genome organization, function, and regulation. For example, the clustering of genes that are involved in specific pathways or functions can provide information about how those pathways or functions have evolved over time. Similarly, the spatial arrangement of genes relative to each other can influence their expression levels and patterns, which can have important consequences for phenotypic traits.

Overall, gene order is an important aspect of genome biology that continues to be a focus of research in fields such as genomics, genetics, evolutionary biology, and bioinformatics.

Virulence, in the context of medicine and microbiology, refers to the degree or severity of damage or harm that a pathogen (like a bacterium, virus, fungus, or parasite) can cause to its host. It is often associated with the ability of the pathogen to invade and damage host tissues, evade or suppress the host's immune response, replicate within the host, and spread between hosts.

Virulence factors are the specific components or mechanisms that contribute to a pathogen's virulence, such as toxins, enzymes, adhesins, and capsules. These factors enable the pathogen to establish an infection, cause tissue damage, and facilitate its transmission between hosts. The overall virulence of a pathogen can be influenced by various factors, including host susceptibility, environmental conditions, and the specific strain or species of the pathogen.

Tryptophan is an essential amino acid, meaning it cannot be synthesized by the human body and must be obtained through dietary sources. Its chemical formula is C11H12N2O2. Tryptophan plays a crucial role in various biological processes as it serves as a precursor to several important molecules, including serotonin, melatonin, and niacin (vitamin B3). Serotonin is a neurotransmitter involved in mood regulation, appetite control, and sleep-wake cycles, while melatonin is a hormone that regulates sleep-wake patterns. Niacin is essential for energy production and DNA repair.

Foods rich in tryptophan include turkey, chicken, fish, eggs, cheese, milk, nuts, seeds, and whole grains. In some cases, tryptophan supplementation may be recommended to help manage conditions related to serotonin imbalances, such as depression or insomnia, but this should only be done under the guidance of a healthcare professional due to potential side effects and interactions with other medications.

Leucine-Responsive Regulatory Protein (LRP) is not a well-established medical term, but it is a term used in biochemistry and molecular biology. It generally refers to a protein that is involved in the regulation of gene expression in response to leucine, an essential amino acid.

Leucine is known to stimulate protein synthesis and inhibit protein degradation in cells. LRP plays a crucial role in this process by acting as a sensor for leucine levels in the cell. When leucine levels are high, LRP becomes activated and binds to specific DNA sequences called response elements, which are located in the promoter regions of genes that are involved in protein synthesis and degradation. This binding leads to the activation or repression of these genes, thereby regulating protein metabolism in the cell.

In summary, Leucine-Responsive Regulatory Protein is a protein that regulates gene expression in response to leucine levels, playing a critical role in the regulation of protein synthesis and degradation in cells.

DNA-directed RNA polymerases are enzymes that synthesize RNA molecules using a DNA template in a process called transcription. These enzymes read the sequence of nucleotides in a DNA molecule and use it as a blueprint to construct a complementary RNA strand.

The RNA polymerase moves along the DNA template, adding ribonucleotides one by one to the growing RNA chain. The synthesis is directional, starting at the promoter region of the DNA and moving towards the terminator region.

In bacteria, there is a single type of RNA polymerase that is responsible for transcribing all types of RNA (mRNA, tRNA, and rRNA). In eukaryotic cells, however, there are three different types of RNA polymerases: RNA polymerase I, II, and III. Each type is responsible for transcribing specific types of RNA.

RNA polymerases play a crucial role in gene expression, as they link the genetic information encoded in DNA to the production of functional proteins. Inhibition or mutation of these enzymes can have significant consequences for cellular function and survival.

Nucleic acid conformation refers to the three-dimensional structure that nucleic acids (DNA and RNA) adopt as a result of the bonding patterns between the atoms within the molecule. The primary structure of nucleic acids is determined by the sequence of nucleotides, while the conformation is influenced by factors such as the sugar-phosphate backbone, base stacking, and hydrogen bonding.

Two common conformations of DNA are the B-form and the A-form. The B-form is a right-handed helix with a diameter of about 20 Å and a pitch of 34 Å, while the A-form has a smaller diameter (about 18 Å) and a shorter pitch (about 25 Å). RNA typically adopts an A-form conformation.

The conformation of nucleic acids can have significant implications for their function, as it can affect their ability to interact with other molecules such as proteins or drugs. Understanding the conformational properties of nucleic acids is therefore an important area of research in molecular biology and medicine.

In genetics, sequence alignment is the process of arranging two or more DNA, RNA, or protein sequences to identify regions of similarity or homology between them. This is often done using computational methods to compare the nucleotide or amino acid sequences and identify matching patterns, which can provide insight into evolutionary relationships, functional domains, or potential genetic disorders. The alignment process typically involves adjusting gaps and mismatches in the sequences to maximize the similarity between them, resulting in an aligned sequence that can be visually represented and analyzed.

DNA restriction enzymes, also known as restriction endonucleases, are a type of enzyme that cut double-stranded DNA at specific recognition sites. These enzymes are produced by bacteria and archaea as a defense mechanism against foreign DNA, such as that found in bacteriophages (viruses that infect bacteria).

Restriction enzymes recognize specific sequences of nucleotides (the building blocks of DNA) and cleave the phosphodiester bonds between them. The recognition sites for these enzymes are usually palindromic, meaning that the sequence reads the same in both directions when facing the opposite strands of DNA.

Restriction enzymes are widely used in molecular biology research for various applications such as genetic engineering, genome mapping, and DNA fingerprinting. They allow scientists to cut DNA at specific sites, creating precise fragments that can be manipulated and analyzed. The use of restriction enzymes has been instrumental in the development of recombinant DNA technology and the Human Genome Project.

Anaerobiosis is a state in which an organism or a portion of an organism is able to live and grow in the absence of molecular oxygen (O2). In biological contexts, "anaerobe" refers to any organism that does not require oxygen for growth, and "aerobe" refers to an organism that does require oxygen for growth.

There are two types of anaerobes: obligate anaerobes, which cannot tolerate the presence of oxygen and will die if exposed to it; and facultative anaerobes, which can grow with or without oxygen but prefer to grow in its absence. Some organisms are able to switch between aerobic and anaerobic metabolism depending on the availability of oxygen, a process known as "facultative anaerobiosis."

Anaerobic respiration is a type of metabolic process that occurs in the absence of molecular oxygen. In this process, organisms use alternative electron acceptors other than oxygen to generate energy through the transfer of electrons during cellular respiration. Examples of alternative electron acceptors include nitrate, sulfate, and carbon dioxide.

Anaerobic metabolism is less efficient than aerobic metabolism in terms of energy production, but it allows organisms to survive in environments where oxygen is not available or is toxic. Anaerobic bacteria are important decomposers in many ecosystems, breaking down organic matter and releasing nutrients back into the environment. In the human body, anaerobic bacteria can cause infections and other health problems if they proliferate in areas with low oxygen levels, such as the mouth, intestines, or deep tissue wounds.

Escherichia coli (E. coli) K12 is a strain of the bacterium E. coli that is commonly used in scientific research. It was originally isolated from the human intestine and has been well-studied due to its relatively harmless nature compared to other strains of E. coli that can cause serious illness.

The "K12" designation refers to a specific set of genetic characteristics that distinguish this strain from others. It is a non-pathogenic, or non-harmful, strain that is often used as a model organism in molecular biology and genetics research. Researchers have developed many tools and resources for studying E. coli K12, including a complete genome sequence and extensive collections of mutant strains.

E. coli K12 is not typically found in the environment and is not associated with disease in healthy individuals. However, it can be used as an indicator organism to detect fecal contamination in water supplies, since it is commonly present in the intestines of warm-blooded animals.

Lactose is a disaccharide, a type of sugar, that is naturally found in milk and dairy products. It is made up of two simple sugars, glucose and galactose, linked together. In order for the body to absorb and use lactose, it must be broken down into these simpler sugars by an enzyme called lactase, which is produced in the lining of the small intestine.

People who have a deficiency of lactase are unable to fully digest lactose, leading to symptoms such as bloating, diarrhea, and abdominal cramps, a condition known as lactose intolerance.

Operons are also found in viruses such as bacteriophages. For example, T7 phages have two operons. The first operon codes for ... This allows for expression of the operon. The lac operon is a negatively controlled inducible operon, where the inducer ... The second operon includes a lysis gene meant to cause the host cell to burst. The term "operon" was first proposed in a short ... The first operon to be described was the lac operon in E. coli. The 1965 Nobel Prize in Physiology and Medicine was awarded to ...
ODB (Operon DataBase) is a database of conserved operons in sequenced genomes. Operon Okuda, Shujiro; Yoshizawa Akiyasu C (Jan ... http://operondb.jp/ v t e (Biological databases, Gene expression, Operons, All stub articles, Biological database stubs). ... 2011). "ODB: a database for operon organizations, 2011 update". Nucleic Acids Res. England. 39 (Database issue): D552-5. doi: ...
Transcription of the tyrT operon is activated by the stringent response. Binding of the FIS protein to the operon's upstream ... The tyrT operon is a series of genes encoding the tRNA for tyrosine in Escherichia coli. It is activated in response to amino ... The tyrT operon consists of an upstream activation sequence, the gene for the tyrosine tRNA called tRNA1Tyr, and an RNA called ... Bosl M, Kersten H (1991). "A novel RNA product of the tyrT operon of Escherichia coli". Nucleic Acids Research. 19 (21): 5863- ...
The gab operon is responsible for the conversion of γ-aminobutyrate (GABA) to succinate. The gab operon comprises three ... The gab operon contributes to homeostasis of polyamines such as putrescine, during nitrogen-limited growth. It is also known to ... The gab operon has been characterized in Escherichia coli and significant homologies for the enzymes have been found in ... The gab operon is also known to contribute to polyamine homeostasis during nitrogen-limited growth and to maintain high ...
The glnALG operon is an operon that regulates the nitrogen content of a cell. It codes for the structural gene glnA the two ... Hence along with histidase, glnALG operon maintains homeostasis within the cell. The glnALG operon is regulated by an intricate ... glnALG operon, along with the glnD and glnF and their gene products, plays an extremely important role in regulating the ... Jayakumar, A; I Schulman, D MacNeil; E M Barnes Jr (April 1986). "Role of the Escherichia coli glnALG operon in regulation of ...
The lactose operon (lac operon) is an operon required for the transport and metabolism of lactose in E. coli and many other ... lac operon in NCBI Bookshelf [2] Virtual Cell Animation Collection Introducing: The Lac Operon The lac Operon: Bozeman Science ... Their work on the lac operon won them the Nobel Prize in Physiology in 1965. Bacterial operons are polycistronic transcripts ... regulatory gene for lac operon) produces a protein that blocks RNAP from binding to the operator of the operon. This protein ...
The gal operon is also controlled by CRP-cAMP, similarly to the lac operon. CRP-cAMP binds to the -35 region, promoting ... The gal operon is a prokaryotic operon, which encodes enzymes necessary for galactose metabolism. Repression of gene expression ... The gal operon contains two operators, OE (for external) and OI (for internal). The former is just upstream of the promoter, ... The gal operon of E. coli consists of 4 structural genes: galE (epimerase), galT (galactose transferase), galK (galactokinase ...
The nik operon is an operon required for uptake of nickel ions into the cell. It is present in many bacteria, but has been ... Nickel ion concentration in the cell is regulated through the nik operon. The nik operon consists of six genes. The first five ... gene regulation Operon lac operon Navarro, Clarisse; Wu, Long-Fei; Mandrand-Berthelot, Marie-Andrée (1 September 1993). "The ... The following table summarizes the structure of the nik operon: Regulation of expression of the nikR gene is achieved by two ...
In molecular biology, the ars operon is an operon found in several bacterial taxon. It is required for the detoxification of ... ArsD and ArsR work together to regulate the ars operon. arsenic chaperone, ArsD, encoded by the arsRDABC operon of Escherichia ... It acts as a repressor on the arsRDABC operon when no arsenic is present in the cell. When arsenic is present in the cell ArsR ... Carlin A, Shi W, Dey S, Rosen BP (February 1995). "The ars operon of Escherichia coli confers arsenical and antimonial ...
The gua operon is repressed by GMP and is induced by AMP. Similarly AMP synthesis is repressed by AMP itself while it is ... The operon must respond to changes in the metabolic state of the cell. It is subject to growth rate dependent control, ... The gua operon is responsible for regulating the synthesis of guanosine mono phosphate (GMP), a purine nucleotide, from inosine ... This complex binds to a region 100 bp upstream of the guaB transcription start site which then represses the gua operon. It is ...
The CPS operon contains genes which code for the following proteins: Wza - a lipoprotein which may form a channel in the ... The same operon is present in Klebsiella species, possibly as a result of horizontal gene transfer. Whitfield C (2006). " ... The CPS operon is likely transcriptionally regulated by the Rcs (regulation of capsule synthesis) proteins. Reduced levels of ... The capsule biosynthesis, or CPS operon, is a section of the genome present in some Escherichia coli, of which regulates the ...
The trp operon is well-studied and is commonly used as an example of gene regulation in bacteria alongside the lac operon. trp ... The trp operon was first characterized in Escherichia coli, and it has since been discovered in many other bacteria. The operon ... The operon operates by a negative repressible feedback mechanism. The repressor for the trp operon is produced upstream by the ... The trp operon additionally uses attenuation to control expression of the operon, a second negative feedback control mechanism ...
The threonine operon leader is an RNA element. Threonine is one of at least 6 amino acid operons are known to be regulated by ... Page for Threonine operon leader at Rfam v t e (Cis-regulatory RNA elements, All stub articles, Molecular and cellular biology ... In each a leader sequence of 150-200 bp is found upstream of the first gene in the operon. This leader sequence can assume two ... In each case the leader also codes for very short peptide sequence that is rich in the end product amino acid of the operon. ...
The Leucine operon leader is an RNA element found upstream of the first gene in the Leucine biosynthetic operon. The leader ... This allows RNA polymerase to transcribe the operon. At least 6 amino acid operons are known to be regulated by attenuation. ... Page for Leucine operon leader at Rfam v t e (Articles needing additional references from April 2020, All articles needing ... The terminator structure is recognised as a termination signal for RNA polymerase and the operon is not transcribed. This ...
The Histidine operon leader is an RNA element found in the bacterial histidine operon. At least 6 amino acid operons are known ... Page for Histidine operon leader at Rfam v t e (Cis-regulatory RNA elements, All stub articles, Molecular and cellular biology ... In each a leader sequence of 150-200 bp is found upstream of the first gene in the operon. This leader sequence can assume two ... In each case the leader also codes for very short peptide sequence that is rich in the end product amino acid of the operon. ...
The Tryptophan operon leader is an RNA element found at the 5′ of some bacterial tryptophan operons. The leader sequence can ... This allows RNA polymerase to transcribe the operon. At least 6 different amino acid operons are known to be regulated by this ... Page for Tryptophan operon leader at Rfam v t e (Cis-regulatory RNA elements, All stub articles, Molecular and cellular biology ... This causes the anti-terminator loop to form and the tryptophan operon to be transcribed. Kolter, R; Yanofsky C (1982). " ...
Operon Catabolism Catabolite repression Other operon systems in E. coli: gal operon gab operon lac operon trp operon Voet, ... The L-arabinose operon, also called the ara or araBAD operon, is an operon required for the breakdown of the five-carbon sugar ... The L-arabinose operon has been commonly used in protein expression system, as the araBAD promoter can be used for producing ... The L-arabinose operon has been a focus for research in molecular biology since 1970, and has been investigated extensively at ...
Page for Alpha operon ribosome binding site at Rfam v t e (Cis-regulatory RNA elements, All stub articles, Molecular and ... The alpha operon ribosome binding site in bacteria is surrounded by this complex pseudoknotted RNA structure. Translation of ... Schlax PJ, Xavier KA, Gluick TC, Draper DE (October 2001). "Translational repression of the Escherichia coli alpha operon mRNA ...
Operon. (Articles with ISNI identifiers, Articles with VIAF identifiers, Articles with LCCN identifiers, Articles with PLWABN ...
Sendecka Zyta, Szedzianis Elzbieta "The Books seria Vademecum of High school examination". (Operon, 2010). ISBN 9788376801926 ...
The Lactose Operon. 1970. ISBN 978-0-317-11809-4. Collins, J. F. (1962). "Estimation of penicillinase in single bacterial cells ...
"Operon Racing - Gutek's bio". www.operonracing.com. Retrieved 2022-01-05. v t e (Articles with topics of unclear notability ...
"Operon Racing - Gutek's bio". www.operonracing.com. "News - Gutek 3rd of the Caribbean 600 - Vendée Globe - En". www. ...
Operon analyses have been reported. MerP is a periplasmic Hg2+-binding receptor of about 70-80 amino acyl residues, synthesized ... The MerC protein encoded on the IncJ plasmid pMERPH of the Shewanella putrefaciens mercuric resistance operon is 137 amino ... Velasco, A.; Acebo, P.; Flores, N.; Perera, J. (1999-01-01). "The mer operon of the acidophilic bacterium Thiobacillus T3.2 ... "Sequence and analysis of a plasmid-encoded mercury resistance operon from Mycobacterium marinum identifies MerH, a new mercuric ...
Jacob, F.; Ullman, A.; Monod, J. (1964). "The Promotor, A Genetic Element Necessary to the Expression of an Operon". Comptes ... Jacob, F. O. (2011). "The Birth of the Operon". Science. 332 (6031): 767. Bibcode:2011Sci...332..767J. doi:10.1126/science. ... "The operon: A group of genes with expression coordinated by an operator. C.R.Acad. Sci. Paris 250 (1960) 1727-1729". Comptes ... Operon: a group of genes with the expression coordinated by an operator] (PDF). Comptes rendus hebdomadaires des séances de ...
It is coded for by the lacA gene of the lac operon in E. coli. It catalyzes the following reaction: acetyl-CoA + beta-D- ... The enzyme's role in the classical E.coli lac operon remains unclear. However, the enzyme's cellular role may be to detoxify ... Transacetylase Wang XG, Olsen LR, Roderick SL (April 2002). "Structure of the lac operon galactoside acetyltransferase". ... "Thiogalactoside transacetylase of the lactose operon as an enzyme for detoxification". 1976. {{cite journal}}: Cite journal ...
Sung YC, Fuchs JA (October 1988). "Characterization of the cyn operon in Escherichia coli K12". The Journal of Biological ... Anderson PM, Sung YC, Fuchs JA (December 1990). "The cyanase operon and cyanate metabolism". FEMS Microbiology Reviews. 7 (3-4 ...
Lawrence, Jeffrey G.; Roth, John R. (1996-08-01). "Selfish Operons: Horizontal Transfer May Drive the Evolution of Gene ... Pál, Csaba; Hurst, Laurence D (2004-06-01). "Evidence against the selfish operon theory". Trends in Genetics. 20 (6): 232-234. ...
That said, they constitute an operon. The SOS genes share a common regulatory mechanism and constitutes a general defense ...
Regulation is different for each operon. The ilvGMEDA operon encodes the ilvGM (ALS II) pair as well as a branched-chain-amino- ... The ilvBNC operon encodes the ilvBN (ALS I) pair and a ketol-acid reductoisomerase (ilvC). It is similarly regulated, but is ... Both of these operons as well as the third, ilvIH, are regulated by leucine-responsive protein (Lrp). Inhibitors of ALS are ... Each subunit pair, or ALS I, II, and III respectively, is located on its own operon, ilvBN, ilvGM and ilvIH (where ilvN ...
Operons are also found in viruses such as bacteriophages. For example, T7 phages have two operons. The first operon codes for ... This allows for expression of the operon. The lac operon is a negatively controlled inducible operon, where the inducer ... The second operon includes a lysis gene meant to cause the host cell to burst. The term "operon" was first proposed in a short ... The first operon to be described was the lac operon in E. coli. The 1965 Nobel Prize in Physiology and Medicine was awarded to ...
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Eurofins MWG Operon is now offering sequencing services on Life Technologies Ion Proton, including exome sequencing under Life ... Eurofins MWG Operon is now offering sequencing services on Life Technologies Ion Proton, including exome sequencing under Life ...
Guided Exploration on Lac Operon Function * lac operon - Guided Exploration - Blank.docx - 17 kB ... lac operon - Guided Exploration - Answered.docx - 18 kB Download all files as a compressed .zip سه‌ردێر Guided Exploration on ... This activity will guide a student to understand how each molecule in this simulation functions to regulate lac operon gene ...
A expressão do operon groESL é regulada por choque térmico e durante o ciclo celular a temperaturas normais, sendo a ... The expression of the groESL operon is induced by heat shock and is cell cycle controlled at normal temperatures, with maximal ... Expressão do operon de choque térmico groESL durante o ciclo celular de Caulobacter crescentus ... Cell cycle expression of the heat shock groESL operon in Caulobacter crescentus ...
If you have used this database, please ensure that you acknowledge this most recent Pseudomonas Genome Database publication rather than just the website URL. Thank you!. Winsor GL, Griffiths EJ, Lo R, Dhillon BK, Shay JA, Brinkman FS (2016 ...
Learn Glucoses Impact on Lac Operon with free step-by-step video explanations and practice problems by experienced tutors. ... predict which of the following conditions of extracellular lactose and glucose would cause regulation of the lac operon to ... predict which of the following conditions of extracellular lactose and glucose would cause regulation of the lac operon to ...
Plik Biologia 1 LO Operon rozszarzona.pdf na koncie użytkownika Klaryssas • folder Szkoła podstawowa i średnia • Data dodania: ... Biologia 1 LO Operon rozszarzona.pdf. Klaryssas / Edukacja / Szkoła podstawowa i średnia / Biologia 1 LO Operon rozszarzona.pdf ...
Operon Origins News und OROUSDT Kursdiagramme. Kostenlose Echtzeit-Kurse und aktive Aktienmarkt-Foren. ...
Operons. Operon name: PSPA7_6247-PSPA7_6248-PSPA7_6249-PSPA7_6250-PSPA7_6251 (5 gene members) ...
Home » Pre-Tenure Publication » Novel estuarine bacterioplankton in rRNA operon libraries from the Chesapeake Bay. ... In the present study, 6 rRNA operon libraries constructed along the salinity gradient in the Chesapeake Bay in 2 different ...
Genes located near the beginning of the operon produce more proteins than genes at the end of the operon. ... Operon Synteny Brings Order to the Case for Intelligent Design, Part 1 (of 2). by Fazale Rana ... Gene Position in Operons. Genes are not positioned randomly along the DNA molecule. Instead, as I discuss in The Cells Design ... It looks as if operons are "all that they can be," and it is rational to see these structures as the work of a Creator. Next ...
This work clarifies and dissects the roles of the flv4-2 operon-encoded proteins, Flv2/Flv4 heterodimer and the elusive Sll0218 ... PCC 6803, the flv4-2 operon encodes the flavodiiron proteins Flv2 and Flv4 together with a small protein, Sll0218, providing ... Further, the characteristic antenna uncoupling feature of the flv4-2 operon mutants is shown to be related to PSII ... Dissecting the Photoprotective Mechanism Encoded by the flv4-2 Operon: a Distinct Contribution of Sll0218 in Photosystem II ...
We show here that this promoter drives the expression of an operon consisting of a bacteriocin gene (sppQ), a cognate immunity ... Characterization of a new bacteriocin operon in sakacin P-producing Lactobacillus sakei, showing strong translational coupling ... Characterization of a new bacteriocin operon in sakacin P-producing Lactobacillus sakei, showing strong translational coupling ... Characterization of a new bacteriocin operon in sakacin P-producing Lactobacillus sakei, showing strong translational coupling ...
WOODSON, K, DEVINE, KM, ANALYSIS OF A RIBOSE TRANSPORT OPERON FROM BACILLUS-SUBTILIS, MICROBIOLOGY-UK, 140, 1994, 1829-1838 ...
Bacterial Genetic Diversity and Operons: Student Learning Guide. *If your instructor has assigned this Student Learning Guide ... Click here to return to the Bacterial Genetic Diversity and Operons Main Menu ...
The relative fitness of strains with restored rrnB operons was 1 to 2% higher than that of the mutant strain. The rrnB operon ... The relative fitness of strains with restored rrnB operons was 1 to 2% higher than that of the mutant strain. The rrnB operon ... The relative fitness of strains with restored rrnB operons was 1 to 2% higher than that of the mutant strain. The rrnB operon ... The relative fitness of strains with restored rrnB operons was 1 to 2% higher than that of the mutant strain. The rrnB operon ...
In this work, we identified whole-genome and metagenomic operons via MetaRon (Metagenome and whole-genome opeRon prediction ... We also demonstrate the use of operons as a subset to represent the trends of secondary metabolites in whole-metagenome data ... Presumably, this study is the first organized effort to predict metagenomic operons and perform a detailed analysis in ... Finally, we identified 1,232,407 unique operons from 145 paired-end human gut metagenome samples. We also report strong ...
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Immediate cessation of transcription of the operator-proximal region of the tryptophan operon in E. coli after repression of ... Sequential Derepression and Repression of the Tryptophan Operon in E. coil. scientific article published in Nature ... On the transcription of the tryptophan operon in Escherichia coli. 3. Multicistronic messenger RNA and polarity for ... THE ORDER OF INDUCTION AND DEINDUCTION OF THE ENZYMES OF THE LACTOSE OPERON IN E. COLI. ...
This graph shows the total number of publications written about "Operon" by people in this website by year, and whether "Operon ... "Operon" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH (Medical Subject Headings) ... Dr fimbriae operon of uropathogenic Escherichia coli mediate microtubule-dependent invasion to the HeLa epithelial cell line. J ... Below are the most recent publications written about "Operon" by people in Profiles. ...
Best quality tetracycline resistance operon.S tetracycline resistance operon. Get the online pharmacy tools you need. Viagra is ... Suggested other tetracycline resistance operon tetracycline resistance operon.com We check safety credentials of online ... Our range of products includes medicines, pharmacy tetracycline resistance operon tetracycline resistance operon. Online ... Farmacie Online Levitra tetracycline resistance operon tetracycline resistance operon. info@mentoratquebec. Learn more about ...
Operon Biotech and Healthcare, GVR Hexa¸ No. 428¸ 3rd Floor, 8th Main¸ Koramangala - 4th Block, Bangalore - 560047, Karnataka ... Operon Biotech and Healthcare, GVR Hexa¸ No. 428¸ 3rd Floor, 8th Main¸ Koramangala - 4th Block, Bangalore - 560047, Karnataka. ...
Migliori Farmacie Online Cialis tetracycline resistance operon e coli tetracycline resistance operon e coli.com to view your ... by Justus Liebig, Wiley InterScience (Online service) tetracycline resistance operon e coli tetracycline resistance operon e ... 48 tetracycline resistance operon e coli. Generics, Rx Refills tetracycline resistance operon e coli. Prednisone is used for ... Tetracycline resistance operon e coli. Dapoxetine mexico Published Date: 2019-10-13 Ampicillin sulbactam iv uses ...
Leader sequence of his operon has seven codons for histidine on the trot. In fact, leu operon and his operon rely solely on ... Category: Genetics Tag: structure of trp operon, trp operon, trp repressor Leave a comment ... trp operon, just like many other operons for amino acid biosynthesis, responds to the cellular level of amino acid, here ... trp Operon. Posted on June 1, 2019. May 24, 2022. Author Binod G C 0 ...
tryptophan operon attenuation Tryptophan Operon: History, Structure, Regulation and Attenuation. November 21, 2021. by Pallavi ... Tryptophan Operon: History, Structure, Regulation and Attenuation Introduction The discovery and explanation of the Operon ...
... único operon juntamente com o gene nifX e uma orf. ...
Operon Biotech and Healthcare, GVR Hexa¸ No. 428¸ 3rd Floor, 8th Main¸ Koramangala - 4th Block, Bangalore - 560047, Karnataka ... Operon Biotech and Healthcare, GVR Hexa¸ No. 428¸ 3rd Floor, 8th Main¸ Koramangala - 4th Block, Bangalore - 560047, Karnataka. ...
  • In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter. (wikipedia.org)
  • The result of this is that the genes contained in the operon are either expressed together or not at all. (wikipedia.org)
  • Several genes must be co-transcribed to define an operon. (wikipedia.org)
  • This theory suggested that in all cases, genes within an operon are negatively controlled by a repressor acting at a single operator located before the first gene. (wikipedia.org)
  • Today, the operon is simply defined as a cluster of genes transcribed into a single mRNA molecule. (wikipedia.org)
  • rRNA genes often exist in operons that have been found in a range of eukaryotes including chordates. (wikipedia.org)
  • An operon is made up of several structural genes arranged under a common promoter and regulated by a common operator. (wikipedia.org)
  • It is defined as a set of adjacent structural genes, plus the adjacent regulatory signals that affect transcription of the structural genes.5 The regulators of a given operon, including repressors, corepressors, and activators, are not necessarily coded for by that operon. (wikipedia.org)
  • whereas operons contain a set of genes regulated by the same operator, regulons contain a set of genes under regulation by a single regulatory protein, and stimulons contain a set of genes under regulation by a single cell stimulus. (wikipedia.org)
  • An operon contains one or more structural genes which are generally transcribed into one polycistronic mRNA (a single mRNA molecule that codes for more than one protein). (wikipedia.org)
  • All the structural genes of an operon are turned ON or OFF together, due to a single promoter and operator upstream to them, but sometimes more control over the gene expression is needed. (wikipedia.org)
  • A typical operon consists of a group of structural genes that code for enzymes involved in a metabolic pathway, such as the biosynthesis of an amino acid. (presenternet.com)
  • An operon is a cluster of genes that are transcribed together to give a single messenger RNA (mRNA) molecule, which therefore encodes multiple proteins (Fig. 16.11). (presenternet.com)
  • Structural genes - the genes that are co-regulated by the operon. (presenternet.com)
  • 1 In prokaryotes , genes encoding collaborative proteins are organized as a contiguous sequence called an operon. (reasons.org)
  • Genes located near the start of an operon do more work than most other genes. (reasons.org)
  • These first genes are expressed at higher levels because they are transcribed earlier and more often than genes located elsewhere in the operon. (reasons.org)
  • Genes located near the beginning of the operon produce more proteins than genes at the end of the operon. (reasons.org)
  • The work by the Berkeley investigators indicates that the precise sequencing of operon genes ensure not only that all the right proteins are made, but also that proteins are made at the right levels to support the cell's metabolic demands. (reasons.org)
  • Efficient regulation of bacterial genes in response to the environmental stimulus results in unique gene clusters known as operons. (biomedcentral.com)
  • Attenuation is the regulation of bacterial operons by controlling termination of transcription at a site located before the first structural genes. (thesciencenotes.com)
  • Operons aren't just made up of the coding sequences of genes. (foobrdigital.com)
  • The promoter is found in the DNA of the operon, upstream of (before) the genes. (foobrdigital.com)
  • That is, it is in between the promoter and the genes of the operon. (foobrdigital.com)
  • This causes the RNA polymerase to bind firmly to the promoter and transcribe the genes of the operon much more frequently, leading to the production of many molecules of mRNA.Where do the regulatory proteins come from? (foobrdigital.com)
  • The lac operon is a group of genes in bacteria that are involved in the metabolism of lactose. (edurev.in)
  • An operon is a group of genes that are coregulated . (wikiversity.org)
  • Here, the function of regulation is quite clear: expressing energy and carbon, that a number around 0.2% would be the right genes at the right time will enable the cell to make the expected, and that the difference is more or less specific to the lac most of the resources within its reach, by maximizing the uptake operon [7]. (lu.se)
  • Pneumococci lacking RafK showed a 50- to 80-fold reduction in expression of the raf operon genes aga (alpha-galactosidase) and rafEFG (raffinose substrate binding and permease genes), and both glucose and sucrose inhibited raffinose uptake through inducer exclusion. (lu.se)
  • Like RafK, the presence of DLDH also activated the expression of raf operon genes, as DLDH-negative pneumococci showed a significantly decreased expression of aga and rafEFG, but DLDH did not regulate rafK or the putative regulatory genes rafR and rafS. (lu.se)
  • In the present study, 6 rRNA operon libraries constructed along the salinity gradient in the Chesapeake Bay in 2 different seasons were analyzed and sequenced. (stroudcenter.org)
  • Bacterial community succession corresponds to changes in the phylogenetic identity, growth-response time and rRNA operon (rrn) copy number of culturable populations. (mpg.de)
  • Genotyping based on partial DNA sequences corresponding to the variable regions of the hsp65 gene and 16S-23S rRNA operon internal transcribed spacer region and randomly amplified polymorphic DNA-PCR analysis showed that both morphotypes belong to a single genotype. (cdc.gov)
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  • The first operon to be described was the lac operon in E. coli. (wikipedia.org)
  • A mutant strain of Escherichia coli was created by inserting a cassette encoding sucrose sensitivity and neomycin resistance (sacB-neo) into the small-subunit rRNA-encoding gene rrs in the rrnB operon. (northwestern.edu)
  • MetaRon consistently achieved high operon prediction sensitivity, specificity and accuracy across E. coli whole-genome (97.8, 94.1 and 92.4%), simulated genome (93.7, 75.5 and 88.1%) and E. coli c20 (87, 91 and 88%,), respectively. (biomedcentral.com)
  • Dr fimbriae operon of uropathogenic Escherichia coli mediate microtubule-dependent invasion to the HeLa epithelial cell line. (childrensmercy.org)
  • Sequential transcription and translation in the lactose operon of Escherichia coli. (wikidata.org)
  • Simultaneous initiation of transcription and translation at internal sites in the tryptophan operon of E. coli. (wikidata.org)
  • Immediate cessation of transcription of the operator-proximal region of the tryptophan operon in E. coli after repression of the operon. (wikidata.org)
  • We demonstrate the power of the method by uncovering several novel features of an iconic gene regulatory program: the induction of Escherichia coli 's lac operon in response to a switch from glucose to lactose. (nature.com)
  • The lac operon of E. coli is but one example of how enzyme and transporter production can be made conditional on the presence of a nutrient to catabolize. (lu.se)
  • In the case of the lac operon of E. coli, a well-studied system for whether a gene is regulated. (lu.se)
  • The operon on plasmid in E. coli was found to result in the production of all three subunit polypeptides [7]. (lu.se)
  • However, the E. coli cells did not show increased succinate dehydrogenase activity nor did the operon complement a sdhCDAB defective E. coli mutant [7]. (lu.se)
  • PCC 6803, the flv4-2 operon encodes the flavodiiron proteins Flv2 and Flv4 together with a small protein, Sll0218, providing photoprotection for Photosystem II (PSII). (uni-muenchen.de)
  • H ducreyi contains a fimbrialike protein (Flp) operon that encodes proteins that contribute to adherence and pathogenesis. (medscape.com)
  • Originally, operons were thought to exist solely in prokaryotes (which includes organelles like plastids that are derived from bacteria), but since the discovery of the first operons in eukaryotes in the early 1990s, more evidence has arisen to suggest they are more common than previously assumed. (wikipedia.org)
  • Operons occur primarily in prokaryotes but also in some eukaryotes, including nematodes such as C. elegans and the fruit fly, Drosophila melanogaster. (wikipedia.org)
  • In general, expression of prokaryotic operons leads to the generation of polycistronic mRNAs, while eukaryotic operons lead to monocistronic mRNAs. (wikipedia.org)
  • DOOR: a database for prokaryotic operons. (pseudomonas.com)
  • Three of the enzymes for lactose metabolism are grouped in the lac operon: lacZ, lacY, and lacA (Figure 12.1. (presenternet.com)
  • As a result, the lac operon is less likely to be transcribed even in the presence of lactose. (edurev.in)
  • An operon is made up of 3 basic DNA components: Promoter - a nucleotide sequence that enables a gene to be transcribed. (wikipedia.org)
  • In this work, it was demonstrated that, in a strain overexpressing σ 32 , the levels of groESL transcripts and the synthesis of GroEL are increased, confirming that this factor is responsible for the transcriptional activation of the σ 32 -like promoter of this operon, that also presents a inverted repeat called CIRCE in its regulatory region. (usp.br)
  • We show here that this promoter drives the expression of an operon consisting of a bacteriocin gene (sppQ), a cognate immunity gene (spiQ), another gene with an unknown function (orf4), and a pseudoimmunity gene containing a frameshift mutation (orf5). (nofima.no)
  • The trp operon site overlaps the promoter and binding of the repressor blocks binding of RNA Polymerase. (thesciencenotes.com)
  • When the RNA polymerase binds to the promoter, it transcribes the operon and makes some mRNAs.Most operons have other regulatory DNA sequences in addition to the promoter. (foobrdigital.com)
  • When the repressor binds to the operator, it prevents RNA polymerase from binding to the promoter and/or transcribing the operon. (foobrdigital.com)
  • When an activator is bound to its DNA binding site, it increases transcription of the operon (e.g., by helping RNA polymerase bind to the promoter). (foobrdigital.com)
  • Stomatin/STOPP (stomatin operon partner protein) gene pairs are present in both archaeal and bacterial species, and their protein products may be involved in the quality control of membrane proteins. (rcsb.org)
  • With MetaRon, we were able to remove two notable limitations of existing whole-genome operon prediction methods: (1) generalizability (ability to predict operons in unrelated bacterial genomes), and (2) whole-genome and metagenomic data management. (biomedcentral.com)
  • Cloning and characterization of groE operon in bacillus subtilis (Master's thesis, University of Calgary, Calgary, Canada). (ucalgary.ca)
  • The E.colitrp operon is regulated at two levels ØBlocking the transcription initiation via repressor-operator interaction. (thesciencenotes.com)
  • This work clarifies and dissects the roles of the flv4-2 operon-encoded proteins, Flv2/Flv4 heterodimer and the elusive Sll0218, in photoprotection of the photosynthetic apparatus in Synechosystis. (uni-muenchen.de)
  • Typically, these sequences are binding sites for regulatory proteins , which control how much the operon is transcribed. (foobrdigital.com)
  • These sequences are binding sites for regulatory proteins that turn expression of the operon "up" or "down. (foobrdigital.com)
  • However, the definition of an operon does not require the mRNA to be polycistronic, though in practice, it usually is. (wikipedia.org)
  • charged tRNAs are not available for ribosome that is translating the nascent 5'end of trp operon mRNA. (thesciencenotes.com)
  • Operons aiding microbial survival are crucial in understanding the gene regulation, identification of new pathways and novel products in diverse environmental settings. (biomedcentral.com)
  • Where translation is coupled with transcription to achieve regulation of an operon through secondary RNA structure. (thesciencenotes.com)
  • The lac operon is often used as a model system for studying gene expression and regulation. (edurev.in)
  • Malonate degradation in Acinetobacter baylyi ADP1: operon organization and regulation by MdcR. (cdc.gov)
  • This activity will guide a student to understand how each molecule in this simulation functions to regulate lac operon gene expression. (colorado.edu)
  • The first operon codes for various products, including a special T7 RNA polymerase which can bind to and transcribe the second operon. (wikipedia.org)
  • Therefore, it is not possible to talk of a general regulatory mechanism, because different operons have different mechanisms. (wikipedia.org)
  • Instead, they also contain regulatory DNA sequences that control transcription of the operon. (foobrdigital.com)
  • The Berkeley researchers demonstrated this concept by showing that a linear relationship exists between the location of the gene in the operon and the amount of protein produced. (reasons.org)
  • To produce a protein , the prokaryote's cellular machinery reads the entire operon and uses the information contained to generate a particular type of messenger RNA called a polycistronic RNA. (reasons.org)
  • The first model for the control of protein production was the lac operon. (cshl.edu)
  • Import of these sugars occurs through the previously characterized raffinose ATP-binding cassette (ABC) transport system, encoded by the raf operon, that lacks the necessary ATP-binding protein. (lu.se)
  • How do mutations in the mec operon of these isolates correlate with - oxacillin MICs - antibiograms - and PFGE profiles? (cdc.gov)
  • 3. What is the role of the lacZ gene in the lac operon? (edurev.in)
  • Introduction of Lac Operon in English is available as part of our Biology Class 12 for NEET & Lac Operon in Hindi for Biology Class 12 course. (edurev.in)
  • The expression of the groESL operon is induced by heat shock and is cell cycle controlled at normal temperatures, with maximal transcription in the predivisional cell and very low levels in the stalked cell. (usp.br)
  • Han N. Lim, Yeong Lee, and Razika Hussein, "Fundamental Relationship between Operon Organization and Gene Expression," Proceedings of the National Academy of Sciences, USA (2011), published electronically June 13, 2011, doi: 10.1073/pnas.1105692108. (reasons.org)
  • The lac operon exhibits a phenomenon known as catabolite repression, which means that its expression is suppressed in the presence of high levels of glucose. (edurev.in)
  • The 1965 Nobel Prize in Physiology and Medicine was awarded to François Jacob, André Michel Lwoff and Jacques Monod for their discoveries concerning the operon and virus synthesis. (wikipedia.org)
  • What is operon in biology? (presenternet.com)
  • Studying the lac operon has several practical applications in the field of molecular biology. (edurev.in)
  • Lac Operon for NEET 2023 is part of Biology Class 12 preparation. (edurev.in)
  • Repair of this lesion required flanking regions of DNA that were similar to the six remaining intact rRNA operons and reestablished the full complement of seven rRNA operons. (northwestern.edu)
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  • In this work, we identified whole-genome and metagenomic operons via MetaRon (Metagenome and whole-genome opeRon prediction pipeline). (biomedcentral.com)
  • Experimental identification of metagenomic operons is an intensive and challenging process due to everchanging formulation of operons with respect to environmental stimulus. (biomedcentral.com)
  • Besides explaining types of Lac Operon theory, EduRev gives you an ample number of questions to practice Lac Operon tests, examples and also practice NEET tests. (edurev.in)
  • trp operon, just like many other operons for amino acid biosynthesis, responds to the cellular level of amino acid, here Tryptophan. (thesciencenotes.com)
  • In fact, leu operon and his operon rely solely on attenuation to regulate the biosynthesis of the respective amino acids. (thesciencenotes.com)
  • 4. How does the lac operon respond to glucose levels? (edurev.in)
  • When glucose is available, the concentration of cyclic AMP (cAMP), which is required for the activation of the lac operon, decreases. (edurev.in)
  • The relative fitness of strains with restored rrnB operons was 1 to 2% higher than that of the mutant strain. (northwestern.edu)
  • The operon is switched off whenever cellular level of tryptophan is high (repressible). (thesciencenotes.com)
  • We also demonstrate the use of operons as a subset to represent the trends of secondary metabolites in whole-metagenome data and the role of secondary metabolites in the occurrence of disease condition. (biomedcentral.com)
  • The lac operon is regulated by a system of inducible control. (edurev.in)
  • Operons are also found in viruses such as bacteriophages. (wikipedia.org)