A bacterial DNA topoisomerase II that catalyzes ATP-dependent breakage of both strands of DNA, passage of the unbroken strands through the breaks, and rejoining of the broken strands. Gyrase binds to DNA as a heterotetramer consisting of two A and two B subunits. In the presence of ATP, gyrase is able to convert the relaxed circular DNA duplex into a superhelix. In the absence of ATP, supercoiled DNA is relaxed by DNA gyrase.
DNA TOPOISOMERASES that catalyze ATP-dependent breakage of both strands of DNA, passage of the unbroken strands through the breaks, and rejoining of the broken strands. These enzymes bring about relaxation of the supercoiled DNA and resolution of a knotted circular DNA duplex.
An antibiotic compound derived from Streptomyces niveus. It has a chemical structure similar to coumarin. Novobiocin binds to DNA gyrase, and blocks adenosine triphosphatase (ATPase) activity. (From Reynolds, Martindale The Extra Pharmacopoeia, 30th ed, p189)
Circular duplex DNA isolated from viruses, bacteria and mitochondria in supercoiled or supertwisted form. This superhelical DNA is endowed with free energy. During transcription, the magnitude of RNA initiation is proportional to the DNA superhelicity.
Compounds that inhibit the activity of DNA TOPOISOMERASE II. Included in this category are a variety of ANTINEOPLASTIC AGENTS which target the eukaryotic form of topoisomerase II and ANTIBACTERIAL AGENTS which target the prokaryotic form of topoisomerase II.
COUMARINS with an amino group, exemplified by NOVOBIOCIN.
Synthetic antimicrobial related to NALIDIXIC ACID and used in URINARY TRACT INFECTIONS.
A bacterial DNA topoisomerase II that catalyzes ATP-dependent breakage of both strands of DNA, passage of the unbroken strands through the breaks, and rejoining of the broken strands. Topoisomerase IV binds to DNA as a heterotetramer consisting 2 parC and 2 parE subunits. Topoisomerase IV is a decatenating enzyme that resolves interlinked daughter chromosomes following DNA replication.
Synthetic or naturally occurring substances related to coumarin, the delta-lactone of coumarinic acid.
QUINOLONES containing a 4-oxo (a carbonyl in the para position to the nitrogen). They inhibit the A subunit of DNA GYRASE and are used as antimicrobials. Second generation 4-quinolones are also substituted with a 1-piperazinyl group at the 7-position and a fluorine at the 6-position.
A group of QUINOLONES with at least one fluorine atom and a piperazinyl group.
A group of derivatives of naphthyridine carboxylic acid, quinoline carboxylic acid, or NALIDIXIC ACID.
A synthetic 1,8-naphthyridine antimicrobial agent with a limited bacteriocidal spectrum. It is an inhibitor of the A subunit of bacterial DNA GYRASE.
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.
Substances that prevent infectious agents or organisms from spreading or kill infectious agents in order to prevent the spread of infection.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
DNA TOPOISOMERASES that catalyze ATP-independent breakage of one of the two strands of DNA, passage of the unbroken strand through the break, and rejoining of the broken strand. DNA Topoisomerases, Type I enzymes reduce the topological stress in the DNA structure by relaxing the superhelical turns and knotted rings in the DNA helix.
The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).
A synthetic fluoroquinolone (FLUOROQUINOLONES) with broad-spectrum antibacterial activity against most gram-negative and gram-positive bacteria. Norfloxacin inhibits bacterial DNA GYRASE.
A broad-spectrum antimicrobial carboxyfluoroquinoline.
The ability of bacteria to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).
Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
Substances that reduce the growth or reproduction of BACTERIA.
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.
A synthetic fluoroquinolone antibacterial agent that inhibits the supercoiling activity of bacterial DNA GYRASE, halting DNA REPLICATION.
Proteins found in any species of bacterium.
A broad-spectrum 6-fluoronaphthyridinone antibacterial agent that is structurally related to NALIDIXIC ACID.
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 functional hereditary units of BACTERIA.
CIRCULAR DNA that is interlaced together as links in a chain. It is used as an assay for the activity of DNA TOPOISOMERASES. Catenated DNA is attached loop to loop in contrast to CONCATENATED DNA which is attached end to end.
Naphthyridines are a class of heterocyclic organic compounds containing a naphthyridine nucleus, which is a polycyclic aromatic hydrocarbon made up of two benzene rings fused to a pyridine ring, and they have been studied for their potential pharmacological properties, including as antimicrobial, antiviral, and anticancer agents.
Compounds that inhibit the activity of DNA TOPOISOMERASES.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Enzymes that regulate the topology of DNA by actions such as breaking, relaxing, passing, and rejoining strands of DNA in cells. These enzymes are important components of the DNA replication system. They are classified by their substrate specificities. DNA TOPOISOMERASE I enzymes act on a single strand of DNA. DNA TOPOISOMERASE II enzymes act on double strands of DNA.
A synthetic broad-spectrum fluoroquinolone antibacterial agent active against most gram-negative and gram-positive bacteria.
5'-Adenylic acid, monoanhydride with imidodiphosphoric acid. An analog of ATP, in which the oxygen atom bridging the beta to the gamma phosphate is replaced by a nitrogen atom. It is a potent competitive inhibitor of soluble and membrane-bound mitochondrial ATPase and also inhibits ATP-dependent reactions of oxidative phosphorylation.
A rapid-growing, nonphotochromogenic species of MYCOBACTERIUM originally isolated from human smegma and found also in soil and water. (From Dorland, 28th ed)
The L-isomer of Ofloxacin.
Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.
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.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
A genus of gram-positive, spherical bacteria found in soils and fresh water, and frequently on the skin of man and other animals.
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
A temperate coliphage, in the genus Mu-like viruses, family MYOVIRIDAE, composed of a linear, double-stranded molecule of DNA, which is able to insert itself randomly at any point on the host chromosome. It frequently causes a mutation by interrupting the continuity of the bacterial OPERON at the site of insertion.
A common inhabitant of the vagina and cervix and a potential human pathogen, causing infections of the male and female reproductive tracts. It has also been associated with respiratory disease and pharyngitis. (From Dorland, 28th ed)
The process by which a DNA molecule is duplicated.
Compounds that inhibit the activity of DNA TOPOISOMERASE I.
A substituted dihydroxybenzene used topically as an antiseptic for the treatment of minor skin infections.
A gram-positive organism found in the upper respiratory tract, inflammatory exudates, and various body fluids of normal and/or diseased humans and, rarely, domestic animals.
A family of gram-negative bacteria in the order Methylophilales.
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
Proteins obtained from ESCHERICHIA COLI.
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.
Quinolines are heterocyclic aromatic organic compounds consisting of a two-nitrogened benzene ring fused to a pyridine ring, which have been synthesized and used as building blocks for various medicinal drugs, particularly antibiotics and antimalarials.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
Substances elaborated by specific strains of bacteria that are lethal against other strains of the same or related species. They are protein or lipopolysaccharide-protein complexes used in taxonomy studies of bacteria.
The concentration of a compound needed to reduce population growth of organisms, including eukaryotic cells, by 50% in vitro. Though often expressed to denote in vitro antibacterial activity, it is also used as a benchmark for cytotoxicity to eukaryotic cells in culture.
Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.
Any of the covalently closed DNA molecules found in bacteria, many viruses, mitochondria, plastids, and plasmids. Small, polydisperse circular DNA's have also been observed in a number of eukaryotic organisms and are suggested to have homology with chromosomal DNA and the capacity to be inserted into, and excised from, chromosomal DNA. It is a fragment of DNA formed by a process of looping out and deletion, containing a constant region of the mu heavy chain and the 3'-part of the mu switch region. Circular DNA is a normal product of rearrangement among gene segments encoding the variable regions of immunoglobulin light and heavy chains, as well as the T-cell receptor. (Riger et al., Glossary of Genetics, 5th ed & Segen, Dictionary of Modern Medicine, 1992)
A genus in the family XANTHOMONADACEAE whose cells produce a yellow pigment (Gr. xanthos - yellow). It is pathogenic to plants.
A plasmid whose presence in the cell, either extrachromosomal or integrated into the BACTERIAL CHROMOSOME, determines the "sex" of the bacterium, host chromosome mobilization, transfer via conjugation (CONJUGATION, GENETIC) of genetic material, and the formation of SEX PILI.
Quinolizines are heterocyclic organic compounds containing a bicyclic structure formed by a benzene ring fused to a piperidine ring, which have been used as building blocks in the synthesis of various pharmaceuticals and bioactive molecules.
Azoles of one NITROGEN and two double bonds that have aromatic chemical properties.
Electrophoresis in which agar or agarose gel is used as the diffusion medium.
Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.
Any compound that contains a constituent sugar, in which the hydroxyl group attached to the first carbon is substituted by an alcoholic, phenolic, or other group. They are named specifically for the sugar contained, such as glucoside (glucose), pentoside (pentose), fructoside (fructose), etc. Upon hydrolysis, a sugar and nonsugar component (aglycone) are formed. (From Dorland, 28th ed; From Miall's Dictionary of Chemistry, 5th ed)
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
A non-metabolizable galactose analog that induces expression of the LAC OPERON.
A genus of bacteria that form a nonfragmented aerial mycelium. Many species have been identified with some being pathogenic. This genus is responsible for producing a majority of the ANTI-BACTERIAL AGENTS of practical value.
Peptides whose amino and carboxy ends are linked together with a peptide bond forming a circular chain. Some of them are ANTI-INFECTIVE AGENTS. Some of them are biosynthesized non-ribosomally (PEPTIDE BIOSYNTHESIS, NON-RIBOSOMAL).
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A genus of gram-positive, aerobic bacteria. Most species are free-living in soil and water, but the major habitat for some is the diseased tissue of warm-blooded hosts.
Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.
'Azā compounds' are a class of organic molecules containing at least one nitrogen atom in a five-membered ring, often found in naturally occurring substances and pharmaceuticals, with the name derived from the Arabic word "azZa" meaning 'strong' referring to the ring's aromatic stability.
The rate dynamics in chemical or physical systems.
Single chains of amino acids that are the units of multimeric PROTEINS. Multimeric proteins can be composed of identical or non-identical subunits. One or more monomeric subunits may compose a protomer which itself is a subunit structure of a larger assembly.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
A species of gram-positive bacteria that is a common soil and water saprophyte.
Enzymes that catalyze either the racemization or epimerization of chiral centers within amino acids or derivatives. EC 5.1.1.
A temperate inducible phage and type species of the genus lambda-like viruses, in the family SIPHOVIRIDAE. Its natural host is E. coli K12. Its VIRION contains linear double-stranded DNA with single-stranded 12-base 5' sticky ends. The DNA circularizes on infection.
A species of gram-positive, aerobic bacteria that produces TUBERCULOSIS in humans, other primates, CATTLE; DOGS; and some other animals which have contact with humans. Growth tends to be in serpentine, cordlike masses in which the bacilli show a parallel orientation.
Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
Ring compounds having atoms other than carbon in their nuclei. (Grant & Hackh's Chemical Dictionary, 5th ed)

Phylogenetic structures of the genus Acinetobacter based on gyrB sequences: comparison with the grouping by DNA-DNA hybridization. (1/998)

The phylogenetic relationships of 49 Acinetobacter strains, 46 of which have previously been classified into 18 genomic species by DNA-DNA hybridization studies, were investigated using the nucleotide sequence of gyrB, the structural gene for the DNA gyrase B subunit. The phylogenetic tree showed linkages between genomic species 1 (Acinetobacter calcoaceticus), 2 (Acinetobacter baumannii), 3 and TU13; genomic species 6, BJ15, BJ16 and BJ17; genomic species 5, BJ13 (synonym of TU14) and BJ14; genomic species 7 (Acinetobacter johnsonii), 10 and 11; and genomic species 8 and 9. The phylogenetic grouping of Acinetobacter strains based on gyrB genes was almost congruent with that based on DNA-DNA hybridization studies. Consequently, gyrB sequence comparison can be used to resolve the taxonomic positions of bacterial strains at the level of genomic species. However, minor discrepancies existed in the grouping of strains of genomic species 8, 9 and BJ17. The phylogenetic tree for these strains was reconstructed from the sequence of rpoD, the structural gene for the RNA polymerase sigma 70 factor. The latter tree was 100% congruent with the grouping based on DNA-DNA hybridization. The reliability of DNA-DNA hybridization may be superior to that of sequence comparison of a single protein-encoding gene in resolving closely related organisms since the former method measures the homologies between the nucleotide sequences of total genomic DNAs. Three strains that have not been characterized previously by DNA-DNA hybridization seem to belong to two new genomic species, one including strain ATCC 33308 and the other including strains ATCC 31012 and MBIC 1332.  (+info)

Fluoroquinolone action against clinical isolates of Mycobacterium tuberculosis: effects of a C-8 methoxyl group on survival in liquid media and in human macrophages. (2/998)

When the lethal action of a C-8 methoxyl fluoroquinolone against clinical isolates of Mycobacterium tuberculosis in liquid medium was measured, the compound was found to be three to four times more effective (as determined by measuring the 90% lethal dose) than a C-8-H control fluoroquinolone or ciprofloxacin against cells having a wild-type gyrA (gyrase) gene. Against ciprofloxacin-resistant strains, the C-8 methoxyl group enhanced lethality when alanine was replaced by valine at position 90 of the GyrA protein or when aspartic acid 94 was replaced by glycine, histidine, or tyrosine. During infection of a human macrophage model by wild-type Mycobacterium bovis BCG, the C-8 methoxyl group lowered survival 20- to 100-fold compared with the same concentration of a C-8-H fluoroquinolone. The C-8 methoxyl fluoroquinolone was also more effective than ciprofloxacin against a gyrA Asn94 mutant of M. bovis BCG. In an M. tuberculosis-macrophage system the C-8 methoxyl group improved fluoroquinolone action against both quinolone-susceptible and quinolone-resistant clinical isolates. Thus, a C-8 methoxyl group enhances the bactericidal activity of quinolones with N1-cyclopropyl substitutions; these data encourage further refinement of fluoroquinolones as antituberculosis agents.  (+info)

Impact of gyrA and parC mutations on quinolone resistance, doubling time, and supercoiling degree of Escherichia coli. (3/998)

Isogenic mutants derived from quinolone-susceptible isolate WT by introducing gyrA (S83L, D87G) and parC (S80I, E84K) mutations associated with quinolone resistance were characterized with respect to quinolone resistance, growth rate, and degree of global supercoiling. The latter was determined by use of a pair of reporter plasmids carrying supercoiling-dependent promoters pgyrA and ptopA, respectively, transcriptionally fused to the reporter gene bla coding for TEM-1 beta-lactamase. The quotient (Qsc) of the beta-lactamase specific activity determined for a mutant carrying either plasmid was taken as a measure of the degree of global supercoiling. These Qsc data were comparable to results obtained from the separation of topoisomers of plasmid pBR322 on chloroquine-containing agarose gels and indicate a reduced degree of negative supercoiling in resistant mutants relative to the parent, WT. The S83L mutation in gyrA had the strongest influence on quinolone resistance while leaving other parameters nearly unaffected. The gyrA double mutation (S83L plus D87G) had an effect on quinolone resistance similar to that of a single mutation. Phenotypic expression of the parC mutation (S80I) was dependent on the presence of at least one gyrA mutation. Expression of high-level fluoroquinolone resistance (ciprofloxacin MIC, > 4 micrograms/ml) required a combination of the gyrA double mutation and one parC mutation (S80I or E84K). Such mutants showed considerable alterations of growth rate, global supercoiling, or both. Introduction of a parC mutation affected neither the doubling time nor the degree of supercoiling, while the presence of the gyrA D87G mutation was associated with a significant reduction in the degree of DNA supercoiling.  (+info)

Alterations in GyrA and ParC associated with fluoroquinolone resistance in Enterococcus faecium. (4/998)

High-level quinolone resistance in Enterococcus faecium was associated with mutations in both gyrA and parC genes in 10 of 11 resistant strains. On low-level resistant strain without such mutations may instead possess an efflux mechanism or alterations in the other subunits of the gyrase or topoisomerase IV genes. These findings are similar to those for other gram-positive bacteria, such as Enterococcus faecalis.  (+info)

Mutations in the gyrA, parC, and parE genes associated with fluoroquinolone resistance in clinical isolates of Mycoplasma hominis. (5/998)

Five clinical isolates of Mycoplasma hominis from three different patients were examined for resistance to fluoroquinolones; some of these isolates were probably identical. All five isolates harbored amino acid substitutions in the quinolone resistance-determining regions of both DNA gyrase (GyrA) and topoisomerase IV (ParC or ParE). Furthermore, the novobiocin MIC for three isolates showed a significant increase. This is the first characterization of fluoroquinolone-resistant clinical mycoplasma isolates from humans.  (+info)

In vitro activities of 13 fluoroquinolones against Staphylococcus aureus isolates with characterized mutations in gyrA, gyrB, grlA, and norA and against wild-type isolates. (6/998)

The in vitro activities of 13 fluoroquinolones (FQs) were tested against 90 Staphylococcus aureus clinical isolates: 30 wild type for gyrA, gyrB, grlA and norA and 60 with mutations in these genes. Clinafloxacin (CI-960), sparfloxacin, and grepafloxacin were the most active FQs against wild-type isolates (MICs at which 90% of isolates were inhibited, 0.06 to 0.1 microgram/ml). Mutations in grlA did not affect the MICs of newer FQs. grlA-gyrA double mutations led to higher MICs for all the FQs tested. Efflux mechanisms affected the newer FQs to a much lesser extent than the less recently developed FQs.  (+info)

Cloning and nucleotide sequence analysis of gyrB of Bacillus cereus, B. thuringiensis, B. mycoides, and B. anthracis and their application to the detection of B. cereus in rice. (7/998)

As 16S rRNA sequence analysis has proven inadequate for the differentiation of Bacillus cereus from closely related species, we employed the gyrase B gene (gyrB) as a molecular diagnostic marker. The gyrB genes of B. cereus JCM 2152(T), Bacillus thuringiensis IAM 12077(T), Bacillus mycoides ATCC 6462(T), and Bacillus anthracis Pasteur #2H were cloned and sequenced. Oligonucleotide PCR primer sets were designed from within gyrB sequences of the respective bacteria for the specific amplification and differentiation of B. cereus, B. thuringiensis, and B. anthracis. The results from the amplification of gyrB sequences correlated well with results obtained with the 16S rDNA-based hybridization study but not with the results of their phenotypic characterization. Some of the reference strains of both B. cereus (three serovars) and B. thuringiensis (two serovars) were not positive in PCR amplification assays with gyrB primers. However, complete sequencing of 1.2-kb gyrB fragments of these reference strains showed that these serovars had, in fact, lower homology than their originally designated species. We developed and tested a procedure for the specific detection of the target organism in boiled rice that entailed 15 h of preenrichment followed by PCR amplification of the B. cereus-specific fragment. This method enabled us to detect an initial inoculum of 0.24 CFU of B. cereus cells per g of boiled rice food homogenate without extracting DNA. However, a simple two-step filtration step is required to remove PCR inhibitory substances.  (+info)

Interactions of CcdB with DNA gyrase. Inactivation of Gyra, poisoning of the gyrase-DNA complex, and the antidote action of CcdA. (8/998)

The F plasmid-carried bacterial toxin, the CcdB protein, is known to act on DNA gyrase in two different ways. CcdB poisons the gyrase-DNA complex, blocking the passage of polymerases and leading to double-strand breakage of the DNA. Alternatively, in cells that overexpress CcdB, the A subunit of DNA gyrase (GyrA) has been found as an inactive complex with CcdB. We have reconstituted the inactive GyrA-CcdB complex by denaturation and renaturation of the purified GyrA dimer in the presence of CcdB. This inactivating interaction involves the N-terminal domain of GyrA, because similar inactive complexes were formed by denaturing and renaturing N-terminal fragments of the GyrA protein in the presence of CcdB. Single amino acid mutations, both in GyrA and in CcdB, that prevent CcdB-induced DNA cleavage also prevent formation of the inactive complexes, indicating that some essential interaction sites of GyrA and of CcdB are common to both the poisoning and the inactivation processes. Whereas the lethal effect of CcdB is most probably due to poisoning of the gyrase-DNA complex, the inactivation pathway may prevent cell death through formation of a toxin-antitoxin-like complex between CcdB and newly translated GyrA subunits. Both poisoning and inactivation can be prevented and reversed in the presence of the F plasmid-encoded antidote, the CcdA protein. The products of treating the inactive GyrA-CcdB complex with CcdA are free GyrA and a CcdB-CcdA complex of approximately 44 kDa, which may correspond to a (CcdB)2(CcdA)2 heterotetramer.  (+info)

DNA gyrase is a type II topoisomerase enzyme that plays a crucial role in the negative supercoiling and relaxation of DNA in bacteria. It functions by introducing transient double-stranded breaks into the DNA helix, allowing the strands to pass through one another and thereby reducing positive supercoils or introducing negative supercoils as required for proper DNA function, replication, and transcription.

DNA gyrase is composed of two subunits, GyrA and GyrB, which form a heterotetrameric structure (AB-BA) in the functional enzyme. The enzyme's activity is targeted by several antibiotics, such as fluoroquinolones and novobiocin, making it an essential target for antibacterial drug development.

In summary, DNA gyrase is a bacterial topoisomerase responsible for maintaining the correct supercoiling of DNA during replication and transcription, which can be inhibited by specific antibiotics to combat bacterial infections.

DNA topoisomerases are enzymes that regulate the topological state of DNA during various cellular processes such as replication, transcription, and repair. They do this by introducing temporary breaks in the DNA strands and allowing the strands to rotate around each other, thereby relieving torsional stress and supercoiling. Topoisomerases are classified into two types: type I and type II.

Type II topoisomerases are further divided into two subtypes: type IIA and type IIB. These enzymes function by forming a covalent bond with the DNA strands, cleaving them, and then passing another segment of DNA through the break before resealing the original strands. This process allows for the removal of both positive and negative supercoils from DNA as well as the separation of interlinked circular DNA molecules (catenanes) or knotted DNA structures.

Type II topoisomerases are essential for cell viability, and their dysfunction has been linked to various human diseases, including cancer and neurodegenerative disorders. They have also emerged as important targets for the development of anticancer drugs that inhibit their activity and induce DNA damage leading to cell death. Examples of type II topoisomerase inhibitors include etoposide, doxorubicin, and mitoxantrone.

Novobiocin is an antibiotic derived from the actinomycete species Streptomyces niveus. It belongs to the class of drugs known as aminocoumarins, which function by inhibiting bacterial DNA gyrase, thereby preventing DNA replication and transcription. Novobiocin has activity against a narrow range of gram-positive bacteria, including some strains of Staphylococcus aureus (particularly those resistant to penicillin and methicillin), Streptococcus pneumoniae, and certain mycobacteria. It is used primarily in the treatment of serious staphylococcal infections and is administered orally or intravenously.

It's important to note that Novobiocin has been largely replaced by other antibiotics due to its narrow spectrum of activity, potential for drug interactions, and adverse effects. It is not widely used in clinical practice today.

Superhelical DNA refers to a type of DNA structure that is formed when the double helix is twisted around itself. This occurs due to the presence of negative supercoiling, which results in an overtwisted state that can be described as having a greater number of helical turns than a relaxed circular DNA molecule.

Superhelical DNA is often found in bacterial and viral genomes, where it plays important roles in compacting the genome into a smaller volume and facilitating processes such as replication and transcription. The degree of supercoiling can affect the structure and function of DNA, with varying levels of supercoiling influencing the accessibility of specific regions of the genome to proteins and other regulatory factors.

Superhelical DNA is typically maintained in a stable state by topoisomerase enzymes, which introduce or remove twists in the double helix to regulate its supercoiling level. Changes in supercoiling can have significant consequences for cellular processes, as they can impact the expression of genes and the regulation of chromosome structure and function.

Topoisomerase II inhibitors are a class of anticancer drugs that work by interfering with the enzyme topoisomerase II, which is essential for DNA replication and transcription. These inhibitors bind to the enzyme-DNA complex, preventing the relaxation of supercoiled DNA and causing DNA strand breaks. This results in the accumulation of double-stranded DNA breaks, which can lead to apoptosis (programmed cell death) in rapidly dividing cells, such as cancer cells. Examples of topoisomerase II inhibitors include etoposide, doxorubicin, and mitoxantrone.

Aminocoumarins are a class of antibiotics that inhibit bacterial DNA gyrase, an enzyme necessary for DNA replication and transcription. These antibiotics have a coumarin nucleus with an attached amino group. The most well-known aminocoumarin is novobiocin, which is used to treat various bacterial infections. However, the use of aminocoumarins has become limited due to the emergence of bacterial resistance and the availability of other more effective antibiotics.

Oxolinic acid is an antimicrobial agent primarily used in the treatment of bacterial infections, particularly those caused by Gram-negative bacteria. It functions as a quinolone antibiotic and works by inhibiting the DNA gyrase enzyme in bacteria, thereby preventing DNA replication and transcription.

Oxolinic acid is available in various forms, such as ointments, creams, and eye drops, and is commonly used to treat conditions like conjunctivitis (pink eye) and other superficial bacterial infections of the skin and eyes. It may also be used for other purposes not mentioned in this definition.

It's important to note that oxolinic acid has limited systemic absorption, which means it is not typically used to treat systemic infections. Additionally, as with any medication, it should only be used under the guidance and supervision of a healthcare professional, as misuse or overuse can lead to antibiotic resistance.

DNA Topoisomerase IV is a type of enzyme that plays a crucial role in the relaxation and manipulation of supercoiled DNA during processes such as replication, transcription, and chromosome segregation. It functions by temporarily cleaving and rejoining the DNA strands to allow for the unlinking and separation of DNA molecules. This enzyme primarily targets double-stranded DNA and is especially important in bacteria, where it helps to resolve the topological challenges that arise during DNA replication and segregation of daughter chromosomes during cell division. Inhibition of DNA Topoisomerase IV has been explored as a strategy for developing antibacterial drugs, as this enzyme is essential for bacterial survival and is not found in humans.

Coumarins are a class of organic compounds that occur naturally in certain plants, such as sweet clover and tonka beans. They have a characteristic aroma and are often used as fragrances in perfumes and flavorings in food products. In addition to their use in consumer goods, coumarins also have important medical applications.

One of the most well-known coumarins is warfarin, which is a commonly prescribed anticoagulant medication used to prevent blood clots from forming or growing larger. Warfarin works by inhibiting the activity of vitamin K-dependent clotting factors in the liver, which helps to prolong the time it takes for blood to clot.

Other medical uses of coumarins include their use as anti-inflammatory agents and antimicrobial agents. Some coumarins have also been shown to have potential cancer-fighting properties, although more research is needed in this area.

It's important to note that while coumarins have many medical uses, they can also be toxic in high doses. Therefore, it's essential to use them only under the guidance of a healthcare professional.

4-Quinolones are a class of antibacterial agents that are chemically characterized by a 4-oxo-1,4-dihydroquinoline ring. They include drugs such as ciprofloxacin, levofloxacin, and moxifloxacin, among others. These antibiotics work by inhibiting the bacterial DNA gyrase or topoisomerase IV enzymes, which are essential for bacterial DNA replication, transcription, repair, and recombination. This leads to bacterial cell death.

4-Quinolones have a broad spectrum of activity against both Gram-positive and Gram-negative bacteria and are used to treat a variety of infections, including urinary tract infections, pneumonia, skin and soft tissue infections, and intra-abdominal infections. However, the use of 4-quinolones is associated with an increased risk of tendinitis and tendon rupture, as well as other serious adverse effects such as peripheral neuropathy, QT interval prolongation, and aortic aneurysm and dissection. Therefore, their use should be restricted to situations where the benefits outweigh the risks.

Fluoroquinolones are a class of antibiotics that are widely used to treat various types of bacterial infections. They work by interfering with the bacteria's ability to replicate its DNA, which ultimately leads to the death of the bacterial cells. Fluoroquinolones are known for their broad-spectrum activity against both gram-positive and gram-negative bacteria.

Some common fluoroquinolones include ciprofloxacin, levofloxacin, moxifloxacin, and ofloxacin. These antibiotics are often used to treat respiratory infections, urinary tract infections, skin infections, and gastrointestinal infections, among others.

While fluoroquinolones are generally well-tolerated, they can cause serious side effects in some people, including tendonitis, nerve damage, and changes in mood or behavior. As with all antibiotics, it's important to use fluoroquinolones only when necessary and under the guidance of a healthcare provider.

Quinolones are a class of antibacterial agents that are widely used in medicine to treat various types of infections caused by susceptible bacteria. These synthetic drugs contain a chemical structure related to quinoline and have broad-spectrum activity against both Gram-positive and Gram-negative bacteria. Quinolones work by inhibiting the bacterial DNA gyrase or topoisomerase IV enzymes, which are essential for bacterial DNA replication, transcription, and repair.

The first quinolone antibiotic was nalidixic acid, discovered in 1962. Since then, several generations of quinolones have been developed, with each generation having improved antibacterial activity and a broader spectrum of action compared to the previous one. The various generations of quinolones include:

1. First-generation quinolones (e.g., nalidixic acid): Primarily used for treating urinary tract infections caused by Gram-negative bacteria.
2. Second-generation quinolones (e.g., ciprofloxacin, ofloxacin, norfloxacin): These drugs have improved activity against both Gram-positive and Gram-negative bacteria and are used to treat a wider range of infections, including respiratory, gastrointestinal, and skin infections.
3. Third-generation quinolones (e.g., levofloxacin, sparfloxacin, grepafloxacin): These drugs have enhanced activity against Gram-positive bacteria, including some anaerobes and atypical organisms like Legionella and Mycoplasma species.
4. Fourth-generation quinolones (e.g., moxifloxacin, gatifloxacin): These drugs have the broadest spectrum of activity, including enhanced activity against Gram-positive bacteria, anaerobes, and some methicillin-resistant Staphylococcus aureus (MRSA) strains.

Quinolones are generally well-tolerated, but like all medications, they can have side effects. Common adverse reactions include gastrointestinal symptoms (nausea, vomiting, diarrhea), headache, and dizziness. Serious side effects, such as tendinitis, tendon rupture, peripheral neuropathy, and QT interval prolongation, are less common but can occur, particularly in older patients or those with underlying medical conditions. The use of quinolones should be avoided or used cautiously in these populations.

Quinolone resistance has become an increasing concern due to the widespread use of these antibiotics. Bacteria can develop resistance through various mechanisms, including chromosomal mutations and the acquisition of plasmid-mediated quinolone resistance genes. The overuse and misuse of quinolones contribute to the emergence and spread of resistant strains, which can limit treatment options for severe infections caused by these bacteria. Therefore, it is essential to use quinolones judiciously and only when clinically indicated, to help preserve their effectiveness and prevent further resistance development.

Nalidixic acid is an antimicrobial agent, specifically a synthetic quinolone derivative. It is primarily used for the treatment of urinary tract infections caused by susceptible strains of gram-negative bacteria, such as Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae.

Nalidixic acid works by inhibiting bacterial DNA gyrase, an enzyme necessary for DNA replication. This leads to the prevention of DNA synthesis and ultimately results in bacterial cell death. However, its use has become limited due to the emergence of resistance and the availability of more effective antimicrobials.

It is essential to note that nalidixic acid is not typically used as a first-line treatment for urinary tract infections or any other type of infection. It should only be used when other antibiotics are not suitable due to resistance, allergies, or other factors. Additionally, the drug's potential side effects, such as gastrointestinal disturbances, headaches, and dizziness, may limit its use in some patients.

'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.

Anti-infective agents are a class of medications that are used to treat infections caused by various microorganisms such as bacteria, viruses, fungi, and parasites. These agents work by either killing the microorganism or inhibiting its growth, thereby helping to control the infection and alleviate symptoms.

There are several types of anti-infective agents, including:

1. Antibiotics: These are medications that are used to treat bacterial infections. They work by either killing bacteria (bactericidal) or inhibiting their growth (bacteriostatic).
2. Antivirals: These are medications that are used to treat viral infections. They work by interfering with the replication of the virus, preventing it from spreading and causing further damage.
3. Antifungals: These are medications that are used to treat fungal infections. They work by disrupting the cell membrane of the fungus, killing it or inhibiting its growth.
4. Antiparasitics: These are medications that are used to treat parasitic infections. They work by either killing the parasite or inhibiting its growth and reproduction.

It is important to note that anti-infective agents are not effective against all types of infections, and it is essential to use them appropriately to avoid the development of drug-resistant strains of microorganisms.

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.

DNA topoisomerases are enzymes that modify the topological structure of DNA by regulating the number of twists or supercoils in the double helix. There are two main types of DNA topoisomerases: type I and type II.

Type I DNA topoisomerases function by cutting one strand of the DNA duplex, allowing the uncut strand to rotate around the break, and then resealing the break. This process can relieve both positive and negative supercoiling in DNA, as well as introduce single-stranded breaks into the DNA molecule.

Type I topoisomerases are further divided into three subtypes: type IA, type IB, and type IC. These subtypes differ in their mechanism of action and the structure of the active site tyrosine residue that makes the transient break in the DNA strand.

Overall, DNA topoisomerases play a crucial role in many cellular processes involving DNA, including replication, transcription, recombination, and chromosome segregation. Dysregulation of these enzymes has been implicated in various human diseases, including cancer and genetic disorders.

Microbial drug resistance is a significant medical issue that refers to the ability of microorganisms (such as bacteria, viruses, fungi, or parasites) to withstand or survive exposure to drugs or medications designed to kill them or limit their growth. This phenomenon has become a major global health concern, particularly in the context of bacterial infections, where it is also known as antibiotic resistance.

Drug resistance arises due to genetic changes in microorganisms that enable them to modify or bypass the effects of antimicrobial agents. These genetic alterations can be caused by mutations or the acquisition of resistance genes through horizontal gene transfer. The resistant microbes then replicate and multiply, forming populations that are increasingly difficult to eradicate with conventional treatments.

The consequences of drug-resistant infections include increased morbidity, mortality, healthcare costs, and the potential for widespread outbreaks. Factors contributing to the emergence and spread of microbial drug resistance include the overuse or misuse of antimicrobials, poor infection control practices, and inadequate surveillance systems.

To address this challenge, it is crucial to promote prudent antibiotic use, strengthen infection prevention and control measures, develop new antimicrobial agents, and invest in research to better understand the mechanisms underlying drug resistance.

Norfloxacin is a fluoroquinolone antibiotic that is primarily used to treat bacterial infections of the urinary tract, prostate, and skin. It works by inhibiting the bacterial DNA gyrase, which is an essential enzyme involved in DNA replication. This leads to bacterial cell death. Norfloxacin is available as a generic medication and is usually prescribed in oral form, such as tablets or suspension.

Here's the medical definition of Norfloxacin:

Norfloxacin (norfloxacinum) - A synthetic fluoroquinolone antibiotic with a broad spectrum of activity against gram-positive and gram-negative bacteria, including Pseudomonas aeruginosa. It is used to treat urinary tract infections, prostatitis, and skin infections. Norfloxacin inhibits bacterial DNA gyrase, which results in bacterial cell death. The drug is available as a generic medication and is usually prescribed in oral form, such as tablets or suspension. Common side effects include nausea, diarrhea, headache, and dizziness. Norfloxacin may also cause serious adverse reactions, including tendinitis, tendon rupture, peripheral neuropathy, and central nervous system effects. It is contraindicated in patients with a history of hypersensitivity to quinolones or fluoroquinolones.

Ciprofloxacin is a fluoroquinolone antibiotic that is used to treat various types of bacterial infections, including respiratory, urinary, and skin infections. It works by inhibiting the bacterial DNA gyrase, which is an enzyme necessary for bacterial replication and transcription. This leads to bacterial cell death. Ciprofloxacin is available in oral and injectable forms and is usually prescribed to be taken twice a day. Common side effects include nausea, diarrhea, and headache. It may also cause serious adverse reactions such as tendinitis, tendon rupture, peripheral neuropathy, and central nervous system effects. It is important to note that ciprofloxacin should not be used in patients with a history of hypersensitivity to fluoroquinolones and should be used with caution in patients with a history of seizures, brain injury, or other neurological conditions.

Bacterial drug resistance is a type of antimicrobial resistance that occurs when bacteria evolve the ability to survive and reproduce in the presence of drugs (such as antibiotics) that would normally kill them or inhibit their growth. This can happen due to various mechanisms, including genetic mutations or the acquisition of resistance genes from other bacteria.

As a result, bacterial infections may become more difficult to treat, requiring higher doses of medication, alternative drugs, or longer treatment courses. In some cases, drug-resistant infections can lead to serious health complications, increased healthcare costs, and higher mortality rates.

Examples of bacterial drug resistance include methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE), and multidrug-resistant tuberculosis (MDR-TB). Preventing the spread of bacterial drug resistance is crucial for maintaining effective treatments for infectious diseases.

Microbial sensitivity tests, also known as antibiotic susceptibility tests (ASTs) or bacterial susceptibility tests, are laboratory procedures used to determine the effectiveness of various antimicrobial agents against specific microorganisms isolated from a patient's infection. These tests help healthcare providers identify which antibiotics will be most effective in treating an infection and which ones should be avoided due to resistance. The results of these tests can guide appropriate antibiotic therapy, minimize the potential for antibiotic resistance, improve clinical outcomes, and reduce unnecessary side effects or toxicity from ineffective antimicrobials.

There are several methods for performing microbial sensitivity tests, including:

1. Disk diffusion method (Kirby-Bauer test): A standardized paper disk containing a predetermined amount of an antibiotic is placed on an agar plate that has been inoculated with the isolated microorganism. After incubation, the zone of inhibition around the disk is measured to determine the susceptibility or resistance of the organism to that particular antibiotic.
2. Broth dilution method: A series of tubes or wells containing decreasing concentrations of an antimicrobial agent are inoculated with a standardized microbial suspension. After incubation, the minimum inhibitory concentration (MIC) is determined by observing the lowest concentration of the antibiotic that prevents visible growth of the organism.
3. Automated systems: These use sophisticated technology to perform both disk diffusion and broth dilution methods automatically, providing rapid and accurate results for a wide range of microorganisms and antimicrobial agents.

The interpretation of microbial sensitivity test results should be done cautiously, considering factors such as the site of infection, pharmacokinetics and pharmacodynamics of the antibiotic, potential toxicity, and local resistance patterns. Regular monitoring of susceptibility patterns and ongoing antimicrobial stewardship programs are essential to ensure optimal use of these tests and to minimize the development of antibiotic resistance.

A plasmid is a small, circular, double-stranded DNA molecule that is separate from the chromosomal DNA of a bacterium or other organism. Plasmids are typically not essential for the survival of the organism, but they can confer beneficial traits such as antibiotic resistance or the ability to degrade certain types of pollutants.

Plasmids are capable of replicating independently of the chromosomal DNA and can be transferred between bacteria through a process called conjugation. They often contain genes that provide resistance to antibiotics, heavy metals, and other environmental stressors. Plasmids have also been engineered for use in molecular biology as cloning vectors, allowing scientists to replicate and manipulate specific DNA sequences.

Plasmids are important tools in genetic engineering and biotechnology because they can be easily manipulated and transferred between organisms. They have been used to produce vaccines, diagnostic tests, and genetically modified organisms (GMOs) for various applications, including agriculture, medicine, and industry.

Anti-bacterial agents, also known as antibiotics, are a type of medication used to treat infections caused by bacteria. These agents work by either killing the bacteria or inhibiting their growth and reproduction. There are several different classes of anti-bacterial agents, including penicillins, cephalosporins, fluoroquinolones, macrolides, and tetracyclines, among others. Each class of antibiotic has a specific mechanism of action and is used to treat certain types of bacterial infections. It's important to note that anti-bacterial agents are not effective against viral infections, such as the common cold or flu. Misuse and overuse of antibiotics can lead to antibiotic resistance, which is a significant global health concern.

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.

Ofloxacin is an antibacterial drug, specifically a fluoroquinolone. It works by inhibiting the bacterial DNA gyrase, which is essential for the bacteria to replicate. This results in the death of the bacteria and helps to stop the infection. Ofloxacin is used to treat a variety of bacterial infections, including respiratory tract infections, urinary tract infections, skin infections, and sexually transmitted diseases. It is available in various forms, such as tablets, capsules, and eye drops. As with any medication, it should be used only under the direction of a healthcare professional, and its use may be associated with certain risks and side effects.

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.

Enoxacin is an antibiotic that belongs to a class of drugs called fluoroquinolones. It works by inhibiting the bacterial DNA gyrase, which is an essential enzyme involved in DNA replication and transcription. This leads to bacterial cell death and helps to treat various infections caused by susceptible bacteria. Enoxacin is used to treat a wide range of bacterial infections, including respiratory, urinary tract, skin, and soft tissue infections.

The medical definition of Enoxacin can be stated as:

Enoxacin (INN, USAN, JAN) is a fluoroquinolone antibiotic used to treat various bacterial infections. It is an inhibitor of DNA gyrase and has been found to have good activity against both Gram-positive and Gram-negative bacteria. Enoxacin is available as a 200 mg tablet for oral administration, and its typical dosage ranges from 200 to 600 mg per day, depending on the type and severity of the infection being treated.

It's important to note that like other fluoroquinolones, Enoxacin carries a risk of serious side effects, including tendinitis, tendon rupture, peripheral neuropathy, central nervous system effects, and exacerbation of myasthenia gravis. Therefore, it should be used with caution and only when other antibiotics are not appropriate or have failed.

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 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.

Catenated DNA refers to the linking or interlocking of two or more DNA molecules in a circular form, where the circles are topologically entangled. This occurs during DNA replication when the sister chromatids (identical copies of DNA) are formed and remain interlinked before they are separated during cell division. The term "catenane" is used to describe this interlocking structure. It is important to note that in linear DNA, the term "catenated" does not apply since there is no circular formation.

Naphthyridines are a class of heterocyclic organic compounds that contain a naphthyridine core structure, which is a polycyclic aromatic hydrocarbon made up of two benzene rings fused to a tetrahydropyridine ring. They have a variety of pharmacological activities and are used in the development of various therapeutic agents, including antibiotics, antivirals, and anticancer drugs.

In medical terms, naphthyridines do not have a specific clinical definition or application, but they are rather a chemical class that is utilized in the design and synthesis of drugs with potential therapeutic benefits. The unique structure and properties of naphthyridines make them attractive candidates for drug development, particularly in areas where new treatments are needed to overcome drug resistance or improve efficacy.

It's worth noting that while naphthyridines have shown promise in preclinical studies, further research is needed to fully understand their safety and effectiveness in humans before they can be approved as therapeutic agents.

Topoisomerase inhibitors are a class of anticancer drugs that work by interfering with the function of topoisomerases, which are enzymes responsible for relaxing supercoiled DNA during processes such as replication and transcription. Topoisomerase I inhibitors selectively bind to and stabilize the cleavage complex formed between topoisomerase I and DNA, preventing the relegation of the broken DNA strand and resulting in DNA damage and cell death. Examples include irinotecan and topotecan. Topoisomerase II inhibitors, on the other hand, bind to and stabilize the cleavage complex formed between topoisomerase II and DNA, leading to double-stranded DNA breaks and cell death. Examples include doxorubicin, etoposide, and mitoxantrone. These drugs are used in the treatment of various types of cancer.

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.

DNA topoisomerases are enzymes that play a crucial role in the regulation of DNA topology, which refers to the three-dimensional arrangement of the DNA molecule. These enzymes control the number of twists or coils in the DNA helix by creating temporary breaks in the strands and allowing them to rotate around each other, thereby relieving the torsional stress that builds up during processes such as replication and transcription.

There are two main types of DNA topoisomerases: type I and type II. Type I enzymes create a single-stranded break in the DNA helix, while type II enzymes create a double-stranded break. Both types of enzymes can change the linking number (Lk) of the DNA molecule, which is a topological invariant that describes the overall degree of twist in the helix.

Type I topoisomerases are further divided into two subtypes: type IA and type IB. Type IA enzymes, such as topo I from Escherichia coli, create a transient break in one DNA strand and then pass the other strand through the break before resealing it. In contrast, type IB enzymes, such as human topo I, create a covalent bond with the 3'-phosphate end of the broken strand and then pass the 5'-end through the break before rejoining the ends.

Type II topoisomerases are also divided into two subtypes: type IIA and type IIB. Type IIA enzymes, such as bacterial topo IV and eukaryotic topo II, create a double-stranded break in the DNA helix and then pass another segment of double-stranded DNA through the break before resealing it. Type IIB enzymes, such as bacterial topo III and eukaryotic topo IIIα and β, create a double-stranded break and then pass a single strand of DNA through the break before resealing it.

DNA topoisomerases are important targets for cancer chemotherapy because they are essential for cell division and can be inhibited by drugs such as doxorubicin, etoposide, and irinotecan. However, these drugs can also have significant side effects, including cardiotoxicity and myelosuppression. Therefore, there is ongoing research to develop new topoisomerase inhibitors with improved efficacy and safety profiles.

Pefloxacin is a fluoroquinolone antibiotic that is primarily used to treat various types of bacterial infections, such as respiratory tract infections, urinary tract infections, skin and soft tissue infections, and sexually transmitted diseases. It works by inhibiting the DNA gyrase enzyme in bacteria, which is necessary for their replication and survival.

The medical definition of Pefloxacin can be stated as follows:

Pefloxacin (INN, USAN) - a fluoroquinolone antibiotic with bactericidal activity against a wide range of gram-positive and gram-negative bacteria. It is used to treat various types of infections caused by susceptible organisms, including respiratory tract infections, urinary tract infections, skin and soft tissue infections, and sexually transmitted diseases. Pefloxacin is available as an oral tablet or injection for intravenous use.

It's important to note that the use of fluoroquinolones like pefloxacin should be reserved for treating serious bacterial infections that are unresponsive to other antibiotics, due to concerns about their potential side effects and the risk of developing antibiotic resistance.

Adenylyl Imidodiphosphate (AMP-PNP) is a non-hydrolysable analog of adenosine triphosphate (ATP). ATP is a high-energy molecule that provides energy for many cellular processes, including muscle contraction, protein synthesis, and transport of molecules across cell membranes.

AMP-PNP is used in biochemical research as an ATP substitute to study various enzymatic reactions that require ATP as a substrate. Unlike ATP, AMP-PNP cannot be hydrolyzed by most enzymes, and it remains stable during the reaction, allowing researchers to observe and analyze the reaction kinetics more accurately.

AMP-PNP is also used in structural biology studies to determine the three-dimensional structures of proteins that bind to ATP. The non-hydrolyzable property of AMP-PNP makes it an ideal molecule for co-crystallization with proteins, providing valuable insights into the molecular mechanisms of ATP-dependent enzymes.

"Mycobacterium smegmatis" is a species of fast-growing, non-tuberculous mycobacteria (NTM). It is commonly found in the environment, including soil and water. This bacterium is known for its ability to form resistant colonies called biofilms. While it does not typically cause disease in humans, it can contaminate medical equipment and samples, potentially leading to misdiagnosis or infection. In rare cases, it has been associated with skin and soft tissue infections. It is often used in research as a model organism for studying mycobacterial biology and drug resistance due to its relatively harmless nature and rapid growth rate.

Levofloxacin is an antibiotic medication that belongs to the fluoroquinolone class. It works by interfering with the bacterial DNA replication, transcription, and repair processes, leading to bacterial cell death. Levofloxacin is used to treat a variety of infections caused by susceptible bacteria, including respiratory, skin, urinary tract, and gastrointestinal infections. It is available in various forms, such as tablets, oral solution, and injection, for different routes of administration.

The medical definition of Levofloxacin can be stated as:

Levofloxacin is a synthetic antibacterial drug with the chemical name (-)-(S)-9-fluoro-2,3-dihydro-3-methoxy-10-(4-methyl-1-piperazinyl)-9-oxoanthracene-1-carboxylic acid l-alanyl-l-proline methylester monohydrate. It is the levo isomer of ofloxacin and is used to treat a wide range of bacterial infections by inhibiting bacterial DNA gyrase, thereby preventing DNA replication and transcription. Levofloxacin is available as tablets, oral solution, and injection for oral and parenteral administration.

Staphylococcus aureus is a type of gram-positive, round (coccal) bacterium that is commonly found on the skin and mucous membranes of warm-blooded animals and humans. It is a facultative anaerobe, which means it can grow in the presence or absence of oxygen.

Staphylococcus aureus is known to cause a wide range of infections, from mild skin infections such as pimples, impetigo, and furuncles (boils) to more severe and potentially life-threatening infections such as pneumonia, endocarditis, osteomyelitis, and sepsis. It can also cause food poisoning and toxic shock syndrome.

The bacterium is often resistant to multiple antibiotics, including methicillin, which has led to the emergence of methicillin-resistant Staphylococcus aureus (MRSA) strains that are difficult to treat. Proper hand hygiene and infection control practices are critical in preventing the spread of Staphylococcus aureus and MRSA.

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.

Adenosine triphosphatases (ATPases) are a group of enzymes that catalyze the conversion of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and inorganic phosphate. This reaction releases energy, which is used to drive various cellular processes such as muscle contraction, transport of ions across membranes, and synthesis of proteins and nucleic acids.

ATPases are classified into several types based on their structure, function, and mechanism of action. Some examples include:

1. P-type ATPases: These ATPases form a phosphorylated intermediate during the reaction cycle and are involved in the transport of ions across membranes, such as the sodium-potassium pump and calcium pumps.
2. F-type ATPases: These ATPases are found in mitochondria, chloroplasts, and bacteria, and are responsible for generating a proton gradient across the membrane, which is used to synthesize ATP.
3. V-type ATPases: These ATPases are found in vacuolar membranes and endomembranes, and are involved in acidification of intracellular compartments.
4. A-type ATPases: These ATPases are found in the plasma membrane and are involved in various functions such as cell signaling and ion transport.

Overall, ATPases play a crucial role in maintaining the energy balance of cells and regulating various physiological processes.

"Micrococcus" is a genus of Gram-positive, catalase-positive, aerobic bacteria that are commonly found in pairs or tetrads. They are typically spherical in shape and range from 0.5 to 3 micrometers in diameter. Micrococci are ubiquitous in nature and can be found on the skin and mucous membranes of humans and animals, as well as in soil, water, and air.

Micrococci are generally considered to be harmless commensals, but they have been associated with a variety of infections in immunocompromised individuals, including bacteremia, endocarditis, and pneumonia. They can also cause contamination of medical equipment and supplies, leading to nosocomial infections.

It's worth noting that the taxonomy of this genus has undergone significant revisions in recent years, and many species previously classified as Micrococcus have been reassigned to other genera. As a result, the medical significance of this genus is somewhat limited.

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.

Adenosine Triphosphate (ATP) is a high-energy molecule that stores and transports energy within cells. It is the main source of energy for most cellular processes, including muscle contraction, nerve impulse transmission, and protein synthesis. ATP is composed of a base (adenine), a sugar (ribose), and three phosphate groups. The bonds between these phosphate groups contain a significant amount of energy, which can be released when the bond between the second and third phosphate group is broken, resulting in the formation of adenosine diphosphate (ADP) and inorganic phosphate. This process is known as hydrolysis and can be catalyzed by various enzymes to drive a wide range of cellular functions. ATP can also be regenerated from ADP through various metabolic pathways, such as oxidative phosphorylation or substrate-level phosphorylation, allowing for the continuous supply of energy to cells.

Bacteriophage mu, also known as Mucoid Bacteriophage or Phage Mu, is a type of bacterial virus that infects and replicates within the genetic material of specific bacteria, primarily belonging to the genus Pseudomonas. This phage is characterized by its unique ability to integrate its genome into the host bacterium's chromosome at random locations, which can result in mutations or alterations in the bacterial genome.

Phage Mu has a relatively large genome and encodes various proteins that facilitate its replication, packaging, and release from the host cell. When Phage Mu infects a bacterium, it injects its genetic material into the host cytoplasm, where it circularizes and then integrates itself into the host's chromosome via a process called transposition. This integration can lead to significant changes in the host bacterium's genome, potentially altering its phenotype or even converting it into a lysogenic state, where the phage remains dormant within the host cell until environmental conditions trigger its replication and release.

Phage Mu is widely used as a tool for genetic research due to its ability to introduce random mutations into bacterial genomes, facilitating the study of gene function and regulation. Additionally, Phage Mu has been explored for potential applications in phage therapy, where it could be used to target and eliminate specific bacterial pathogens without adversely affecting other beneficial microorganisms present in the host organism or environment.

Mycoplasma hominis is a species of bacteria that lack a cell wall and are among the smallest free-living organisms. They are commonly found as part of the normal flora in the genitourinary tract of humans, particularly in the urethra, cervix, and vagina. However, they can also cause various infections, especially in individuals with compromised immune systems or in the presence of other risk factors.

M. hominis has been associated with several types of infections, including:

1. Genital tract infections: M. hominis can cause pelvic inflammatory disease (PID), cervicitis, urethritis, and endometritis in women. In men, it may lead to urethritis and prostatitis.
2. Postpartum and post-abortion fever: M. hominis can contribute to febrile morbidity following delivery or abortion.
3. Respiratory tract infections: While rare, M. hominis has been implicated in some cases of respiratory tract infections, particularly in immunocompromised individuals.
4. Joint and soft tissue infections: M. hominis can cause septic arthritis, osteomyelitis, and other soft tissue infections, especially in patients with underlying joint diseases or compromised immune systems.
5. Central nervous system (CNS) infections: Although uncommon, M. hominis has been associated with CNS infections such as meningitis and brain abscesses, primarily in immunocompromised individuals.
6. Bloodstream infections: Bacteremia due to M. hominis is rare but can occur in immunocompromised patients or those with indwelling catheters.

Diagnosis of M. hominis infections typically involves the detection of the organism through various laboratory methods, such as culture, polymerase chain reaction (PCR), or serological tests. Treatment usually consists of antibiotics that target mycoplasmas, such as macrolides (e.g., azithromycin) or tetracyclines (e.g., doxycycline). However, resistance to certain antibiotics has been reported in some M. hominis strains.

DNA replication is the biological process by which DNA makes an identical copy of itself during cell division. It is a fundamental mechanism that allows genetic information to be passed down from one generation of cells to the next. During DNA replication, each strand of the double helix serves as a template for the synthesis of a new complementary strand. This results in the creation of two identical DNA molecules. The enzymes responsible for DNA replication include helicase, which unwinds the double helix, and polymerase, which adds nucleotides to the growing strands.

Topoisomerase I inhibitors are a class of anticancer drugs that work by inhibiting the function of topoisomerase I, an enzyme that plays a crucial role in the relaxation and replication of DNA. By inhibiting this enzyme's activity, these drugs interfere with the normal unwinding and separation of DNA strands, leading to DNA damage and ultimately cell death. Topoisomerase I inhibitors are used in the treatment of various types of cancer, including colon, small cell lung, ovarian, and cervical cancers. Examples of topoisomerase I inhibitors include camptothecin, irinotecan, and topotecan.

Hexylresorcinol is not a medical term per se, but it is a chemical compound that has been used in some medical and cosmetic applications. Here's a definition of Hexylresorcinol from a chemistry perspective:

Hexylresorcinol is an organic compound with the formula (HOC6H4)2CH3. It is a derivative of resorcinol, where two resorcinol molecules are attached to a hexyl group. This aromatic phenolic compound has antiseptic, antibacterial, and analgesic properties, which has led to its use in various medical and consumer products, such as mouthwashes, throat lozenges, and topical creams. It is also used as an antioxidant in food and cosmetic applications.

Please note that while Hexylresorcinol has various uses, it should be handled with care due to its potential toxicity and irritant properties. Always follow the instructions provided by a healthcare professional or manufacturer when using products containing this compound.

Streptococcus pneumoniae, also known as the pneumococcus, is a gram-positive, alpha-hemolytic bacterium frequently found in the upper respiratory tract of healthy individuals. It is a leading cause of community-acquired pneumonia and can also cause other infectious diseases such as otitis media (ear infection), sinusitis, meningitis, and bacteremia (bloodstream infection). The bacteria are encapsulated, and there are over 90 serotypes based on variations in the capsular polysaccharide. Some serotypes are more virulent or invasive than others, and the polysaccharide composition is crucial for vaccine development. S. pneumoniae infection can be treated with antibiotics, but the emergence of drug-resistant strains has become a significant global health concern.

Methylophilaceae is a family of bacteria within the order Burkholderiales. These bacteria are known to be capable of growth on reduced one-carbon compounds such as methanol and formate as their sole source of carbon and energy. They are often found in various environments including soil, water, and sewage sludge. Some species within this family are also known to be able to degrade certain aromatic compounds. It's important to note that medical definition of Methylophilaceae is not commonly used since they are not associated with any specific human disease, but rather studied for their metabolic capabilities and potential applications in bioremediation and bioenergy production.

Enzyme inhibitors are substances that bind to an enzyme and decrease its activity, preventing it from catalyzing a chemical reaction in the body. They can work by several mechanisms, including blocking the active site where the substrate binds, or binding to another site on the enzyme to change its shape and prevent substrate binding. Enzyme inhibitors are often used as drugs to treat various medical conditions, such as high blood pressure, abnormal heart rhythms, and bacterial infections. They can also be found naturally in some foods and plants, and can be used in research to understand enzyme function and regulation.

'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.

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.

Quinolines are a class of organic compounds that consist of a bicyclic structure made up of a benzene ring fused to a piperidine ring. They have a wide range of applications, but they are perhaps best known for their use in the synthesis of various medications, including antibiotics and antimalarial drugs.

Quinolone antibiotics, such as ciprofloxacin and levofloxacin, work by inhibiting the bacterial enzymes involved in DNA replication and repair. They are commonly used to treat a variety of bacterial infections, including urinary tract infections, pneumonia, and skin infections.

Quinoline-based antimalarial drugs, such as chloroquine and hydroxychloroquine, work by inhibiting the parasite's ability to digest hemoglobin in the red blood cells. They are commonly used to prevent and treat malaria.

It is important to note that quinolines have been associated with serious side effects, including tendinitis and tendon rupture, nerve damage, and abnormal heart rhythms. As with any medication, it is important to use quinolines only under the supervision of a healthcare provider, and to follow their instructions carefully.

Deoxyribonucleic acid (DNA) is the genetic material present in the cells of organisms where it is responsible for the storage and transmission of hereditary information. DNA is a long molecule that consists of two strands coiled together to form a double helix. Each strand is made up of a series of four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - that are linked together by phosphate and sugar groups. The sequence of these bases along the length of the molecule encodes genetic information, with A always pairing with T and C always pairing with G. This base-pairing allows for the replication and transcription of DNA, which are essential processes in the functioning and reproduction of all living organisms.

Bacteriocins are ribosomally synthesized antimicrobial peptides produced by bacteria as a defense mechanism against other competing bacterial strains. They primarily target and inhibit the growth of closely related bacterial species, although some have a broader spectrum of activity. Bacteriocins can be classified into different types based on their structural features, molecular masses, and mechanisms of action.

These antimicrobial peptides often interact with the cell membrane of target bacteria, causing pore formation, depolarization, or disrupting cell wall biosynthesis, ultimately leading to bacterial cell death. Bacteriocins have gained interest in recent years as potential alternatives to conventional antibiotics due to their narrow spectrum of activity and reduced likelihood of inducing resistance. They are being explored for use in food preservation, agricultural applications, and as therapeutic agents in the medical field.

Inhibitory Concentration 50 (IC50) is a measure used in pharmacology, toxicology, and virology to describe the potency of a drug or chemical compound. It refers to the concentration needed to reduce the biological or biochemical activity of a given substance by half. Specifically, it is most commonly used in reference to the inhibition of an enzyme or receptor.

In the context of infectious diseases, IC50 values are often used to compare the effectiveness of antiviral drugs against a particular virus. A lower IC50 value indicates that less of the drug is needed to achieve the desired effect, suggesting greater potency and potentially fewer side effects. Conversely, a higher IC50 value suggests that more of the drug is required to achieve the same effect, indicating lower potency.

It's important to note that IC50 values can vary depending on the specific assay or experimental conditions used, so they should be interpreted with caution and in conjunction with other measures of drug efficacy.

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.

Circular DNA is a type of DNA molecule that forms a closed loop, rather than the linear double helix structure commonly associated with DNA. This type of DNA is found in some viruses, plasmids (small extrachromosomal DNA molecules found in bacteria), and mitochondria and chloroplasts (organelles found in plant and animal cells).

Circular DNA is characterized by the absence of telomeres, which are the protective caps found on linear chromosomes. Instead, circular DNA has a specific sequence where the two ends join together, known as the origin of replication and the replication terminus. This structure allows for the DNA to be replicated efficiently and compactly within the cell.

Because of its circular nature, circular DNA is more resistant to degradation by enzymes that cut linear DNA, making it more stable in certain environments. Additionally, the ability to easily manipulate and clone circular DNA has made it a valuable tool in molecular biology and genetic engineering.

Xanthomonas is a genus of Gram-negative, rod-shaped bacteria that are widely distributed in various environments, including water, soil, and plant surfaces. They are known to cause diseases in plants, such as black rot in crucifers, bacterial spot in tomatoes and peppers, and citrus canker in citrus trees. Some species of Xanthomonas can also infect humans, although this is relatively rare. Infections in humans typically occur through contact with contaminated water or soil, and can cause various symptoms such as pneumonia, skin infections, and bloodstream infections. However, it's important to note that Xanthomonas species are not typically associated with human diseases and are mainly known for their impact on plants.

I'm not aware of a widely recognized or established medical term called "F factor." It is possible that it could be a term specific to certain medical specialties, research, or publications. In order to provide an accurate and helpful response, I would need more context or information about where you encountered this term.

If you meant to ask about the F-plasmid, which is sometimes referred to as the "F factor" in bacteriology, it is a type of plasmid that can be found in certain strains of bacteria and carries genes related to conjugation (the process by which bacteria transfer genetic material between each other). The F-plasmid can exist as an independent circular DNA molecule or integrate into the chromosome of the host bacterium.

If this is not the term you were looking for, please provide more context so I can give a better answer.

Quinolizines are not a medical term, but a chemical classification for a group of compounds that contain a quinolizine ring in their structure. A quinolizine ring is a polycyclic aromatic hydrocarbon with eight pi electrons and consists of two benzene rings fused to a piperidine ring.

Quinolizines have been studied for their potential medicinal properties, including anti-malarial, anti-cancer, and anti-microbial activities. However, there are no currently approved drugs that contain quinolizine as the primary active ingredient. Therefore, it is not possible to provide a medical definition of 'Quinolizines.'

"Pyrroles" is not a medical term in and of itself, but "pyrrole" is an organic compound that contains one nitrogen atom and four carbon atoms in a ring structure. In the context of human health, "pyrroles" often refers to a group of compounds called pyrrol derivatives or pyrrole metabolites.

In clinical settings, "pyrroles" is sometimes used to refer to a urinary metabolite called "pyrrole-protein conjugate," which contains a pyrrole ring and is excreted in the urine. Elevated levels of this compound have been associated with certain psychiatric and behavioral disorders, such as schizophrenia and mood disorders. However, the relationship between pyrroles and these conditions is not well understood, and more research is needed to establish a clear medical definition or diagnostic criteria for "pyrrole disorder" or "pyroluria."

Electrophoresis, Agar Gel is a laboratory technique used to separate and analyze DNA, RNA, or proteins based on their size and electrical charge. In this method, the sample is mixed with agarose gel, a gelatinous substance derived from seaweed, and then solidified in a horizontal slab-like format. An electric field is applied to the gel, causing the negatively charged DNA or RNA molecules to migrate towards the positive electrode. The smaller molecules move faster through the gel than the larger ones, resulting in their separation based on size. This technique is widely used in molecular biology and genetics research, as well as in diagnostic testing for various genetic disorders.

Macromolecular substances, also known as macromolecules, are large, complex molecules made up of repeating subunits called monomers. These substances are formed through polymerization, a process in which many small molecules combine to form a larger one. Macromolecular substances can be naturally occurring, such as proteins, DNA, and carbohydrates, or synthetic, such as plastics and synthetic fibers.

In the context of medicine, macromolecular substances are often used in the development of drugs and medical devices. For example, some drugs are designed to bind to specific macromolecules in the body, such as proteins or DNA, in order to alter their function and produce a therapeutic effect. Additionally, macromolecular substances may be used in the creation of medical implants, such as artificial joints and heart valves, due to their strength and durability.

It is important for healthcare professionals to have an understanding of macromolecular substances and how they function in the body, as this knowledge can inform the development and use of medical treatments.

Glycosides are organic compounds that consist of a glycone (a sugar component) linked to a non-sugar component, known as an aglycone, via a glycosidic bond. They can be found in various plants, microorganisms, and some animals. Depending on the nature of the aglycone, glycosides can be classified into different types, such as anthraquinone glycosides, cardiac glycosides, and saponin glycosides.

These compounds have diverse biological activities and pharmacological effects. For instance:

* Cardiac glycosides, like digoxin and digitoxin, are used in the treatment of heart failure and certain cardiac arrhythmias due to their positive inotropic (contractility-enhancing) and negative chronotropic (heart rate-slowing) effects on the heart.
* Saponin glycosides have potent detergent properties and can cause hemolysis (rupture of red blood cells). They are used in various industries, including cosmetics and food processing, and have potential applications in drug delivery systems.
* Some glycosides, like amygdalin found in apricot kernels and bitter almonds, can release cyanide upon hydrolysis, making them potentially toxic.

It is important to note that while some glycosides have therapeutic uses, others can be harmful or even lethal if ingested or otherwise introduced into the body in large quantities.

A Structure-Activity Relationship (SAR) in the context of medicinal chemistry and pharmacology refers to the relationship between the chemical structure of a drug or molecule and its biological activity or effect on a target protein, cell, or organism. SAR studies aim to identify patterns and correlations between structural features of a compound and its ability to interact with a specific biological target, leading to a desired therapeutic response or undesired side effects.

By analyzing the SAR, researchers can optimize the chemical structure of lead compounds to enhance their potency, selectivity, safety, and pharmacokinetic properties, ultimately guiding the design and development of novel drugs with improved efficacy and reduced toxicity.

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

IsoPROPYL THIO-galacto-side (IPTG) is a chemical compound used in molecular biology as an inducer of gene transcription. It is a synthetic analog of allolactose, which is the natural inducer of the lac operon in E. coli bacteria. The lac operon contains genes that code for enzymes involved in the metabolism of lactose, and its expression is normally repressed when lactose is not present. However, when lactose or IPTG is added to the growth medium, it binds to the repressor protein (lac repressor) and prevents it from binding to the operator region of the lac operon, thereby allowing transcription of the structural genes.

IPTG is often used in laboratory experiments to induce the expression of cloned genes that have been placed under the control of the lac promoter. When IPTG is added to the bacterial culture, it binds to the lac repressor and allows for the transcription and translation of the gene of interest. This can be useful for producing large quantities of a particular protein or for studying the regulation of gene expression in bacteria.

It's important to note that IPTG is not metabolized by E.coli, so it remains active in the growth medium throughout the experiment and can be added at any point during the growth cycle.

Streptomyces is a genus of Gram-positive, aerobic, saprophytic bacteria that are widely distributed in soil, water, and decaying organic matter. They are known for their complex morphology, forming branching filaments called hyphae that can differentiate into long chains of spores.

Streptomyces species are particularly notable for their ability to produce a wide variety of bioactive secondary metabolites, including antibiotics, antifungals, and other therapeutic compounds. In fact, many important antibiotics such as streptomycin, neomycin, tetracycline, and erythromycin are derived from Streptomyces species.

Because of their industrial importance in the production of antibiotics and other bioactive compounds, Streptomyces have been extensively studied and are considered model organisms for the study of bacterial genetics, biochemistry, and ecology.

Cyclic peptides are a type of peptides in which the N-terminus and C-terminus of the peptide chain are linked to form a circular structure. This is in contrast to linear peptides, which have a straight peptide backbone with a free N-terminus and C-terminus. The cyclization of peptides can occur through various mechanisms, including the formation of an amide bond between the N-terminal amino group and the C-terminal carboxylic acid group (head-to-tail cyclization), or through the formation of a bond between side chain functional groups.

Cyclic peptides have unique structural and chemical properties that make them valuable in medical and therapeutic applications. For example, they are more resistant to degradation by enzymes compared to linear peptides, which can increase their stability and half-life in the body. Additionally, the cyclic structure allows for greater conformational rigidity, which can enhance their binding affinity and specificity to target molecules.

Cyclic peptides have been explored as potential therapeutics for a variety of diseases, including cancer, infectious diseases, and neurological disorders. They have also been used as tools in basic research to study protein-protein interactions and cell signaling pathways.

X-ray crystallography is a technique used in structural biology to determine the three-dimensional arrangement of atoms in a crystal lattice. In this method, a beam of X-rays is directed at a crystal and diffracts, or spreads out, into a pattern of spots called reflections. The intensity and angle of each reflection are measured and used to create an electron density map, which reveals the position and type of atoms in the crystal. This information can be used to determine the molecular structure of a compound, including its shape, size, and chemical bonds. X-ray crystallography is a powerful tool for understanding the structure and function of biological macromolecules such as proteins and nucleic acids.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

"Mycobacterium" is a genus of gram-positive, aerobic, rod-shaped bacteria that are characterized by their complex cell walls containing large amounts of lipids. This genus includes several species that are significant in human and animal health, most notably Mycobacterium tuberculosis, which causes tuberculosis, and Mycobacterium leprae, which causes leprosy. Other species of Mycobacterium can cause various diseases in humans, including skin and soft tissue infections, lung infections, and disseminated disease in immunocompromised individuals. These bacteria are often resistant to common disinfectants and antibiotics, making them difficult to treat.

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.

'Aza compounds' is a general term used in chemistry to describe organic compounds containing a nitrogen atom (denoted by the symbol 'N' or 'aza') that has replaced a carbon atom in a hydrocarbon structure. The term 'aza' comes from the Greek word for nitrogen, 'azote.'

In medicinal chemistry and pharmacology, aza compounds are of particular interest because the presence of the nitrogen atom can significantly affect the chemical and biological properties of the compound. For example, aza compounds may exhibit enhanced bioavailability, metabolic stability, or receptor binding affinity compared to their non-aza counterparts.

Some common examples of aza compounds in medicine include:

1. Aza-aromatic compounds: These are aromatic compounds that contain one or more nitrogen atoms in the ring structure. Examples include pyridine, quinoline, and isoquinoline derivatives, which have been used as anti-malarial, anti-inflammatory, and anti-cancer agents.
2. Aza-heterocyclic compounds: These are non-aromatic compounds that contain one or more nitrogen atoms in a cyclic structure. Examples include azepine, diazepine, and triazole derivatives, which have been used as anxiolytic, anti-viral, and anti-fungal agents.
3. Aza-peptides: These are peptide compounds that contain one or more nitrogen atoms in the backbone structure. Examples include azapeptides and azabicyclopeptides, which have been used as enzyme inhibitors and neuroprotective agents.
4. Aza-sugars: These are sugar derivatives that contain one or more nitrogen atoms in the ring structure. Examples include azasugars and iminosugars, which have been used as glycosidase inhibitors and anti-viral agents.

Overall, aza compounds represent an important class of medicinal agents with diverse chemical structures and biological activities.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

A protein subunit refers to a distinct and independently folding polypeptide chain that makes up a larger protein complex. Proteins are often composed of multiple subunits, which can be identical or different, that come together to form the functional unit of the protein. These subunits can interact with each other through non-covalent interactions such as hydrogen bonds, ionic bonds, and van der Waals forces, as well as covalent bonds like disulfide bridges. The arrangement and interaction of these subunits contribute to the overall structure and function of the protein.

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.

'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).

Amino acid isomerases are a class of enzymes that catalyze the conversion of one amino acid stereoisomer to another. These enzymes play a crucial role in the metabolism and biosynthesis of amino acids, which are the building blocks of proteins.

Amino acids can exist in two forms, called L- and D-stereoisomers, based on the spatial arrangement of their constituent atoms around a central carbon atom. While most naturally occurring amino acids are of the L-configuration, some D-amino acids are also found in certain proteins and peptides, particularly in bacteria and lower organisms.

Amino acid isomerases can convert one stereoisomer to another by breaking and reforming chemical bonds in a process that requires energy. This conversion can be important for the proper functioning of various biological processes, such as protein synthesis, neurotransmitter metabolism, and immune response.

Examples of amino acid isomerases include proline racemase, which catalyzes the interconversion of L-proline and D-proline, and serine hydroxymethyltransferase, which converts L-serine to D-serine. These enzymes are essential for maintaining the balance of amino acids in living organisms and have potential therapeutic applications in various diseases, including neurodegenerative disorders and cancer.

Bacteriophage lambda, often simply referred to as phage lambda, is a type of virus that infects the bacterium Escherichia coli (E. coli). It is a double-stranded DNA virus that integrates its genetic material into the bacterial chromosome as a prophage when it infects the host cell. This allows the phage to replicate along with the bacterium until certain conditions trigger the lytic cycle, during which new virions are produced and released by lysing, or breaking open, the host cell.

Phage lambda is widely studied in molecular biology due to its well-characterized life cycle and genetic structure. It has been instrumental in understanding various fundamental biological processes such as gene regulation, DNA recombination, and lysis-lysogeny decision.

'Mycobacterium tuberculosis' is a species of slow-growing, aerobic, gram-positive bacteria that demonstrates acid-fastness. It is the primary causative agent of tuberculosis (TB) in humans. This bacterium has a complex cell wall rich in lipids, including mycolic acids, which provides a hydrophobic barrier and makes it resistant to many conventional antibiotics. The ability of M. tuberculosis to survive within host macrophages and resist the immune response contributes to its pathogenicity and the difficulty in treating TB infections.

M. tuberculosis is typically transmitted through inhalation of infectious droplets containing the bacteria, which primarily targets the lungs but can spread to other parts of the body (extrapulmonary TB). The infection may result in a spectrum of clinical manifestations, ranging from latent TB infection (LTBI) to active disease. LTBI represents a dormant state where individuals are infected with M. tuberculosis but do not show symptoms and cannot transmit the bacteria. However, they remain at risk of developing active TB throughout their lifetime, especially if their immune system becomes compromised.

Effective prevention and control strategies for TB rely on early detection, treatment, and public health interventions to limit transmission. The current first-line treatments for drug-susceptible TB include a combination of isoniazid, rifampin, ethambutol, and pyrazinamide for at least six months. Multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of M. tuberculosis present significant challenges in TB control and require more complex treatment regimens.

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.

Heterocyclic compounds are organic compounds that contain at least one atom within the ring structure, other than carbon, such as nitrogen, oxygen, sulfur or phosphorus. These compounds make up a large class of naturally occurring and synthetic materials, including many drugs, pigments, vitamins, and antibiotics. The presence of the heteroatom in the ring can have significant effects on the physical and chemical properties of the compound, such as its reactivity, stability, and bonding characteristics. Examples of heterocyclic compounds include pyridine, pyrimidine, and furan.

Upon binding to DNA (the "Gyrase-DNA" state), there is a competition between DNA wrapping and dissociation, where increasing ... whose single circular DNA is cut by DNA gyrase and the two ends are then twisted around each other to form supercoils. Gyrase ... DNA gyrase, or simply gyrase, is an enzyme within the class of topoisomerase and is a subclass of Type II topoisomerases that ... DNA cleavage and reunion is performed by a catalytic center located in DNA-gates build by all gyrase subunits. C-gates are ...
Novel DNA Gyrase inhibitors. At Trius Pharmaceuticals, Shaw lead the microbiology efforts in designing a screening regimen for ... "Pyrrolopyrimidine inhibitors of DNA gyrase B (GyrB) and topoisomerase IV (ParE). Part I: Structure guided discovery and ... a novel class of DNA gyrase/Topoisomerase IV antibacterial agents that target both Gram-positive and Gram-negative organisms.[2 ... novel DNA gyrase/topoisomerase IV program. These efforts led to the discovery of the TriBE inhibitors, a novel class of agents ...
... including DNA gyrase) achieve this by adding negative supercoils to the DNA helix. Bare single-stranded DNA tends to fold back ... Replication machineries include primosotors are replication enzymes; DNA polymerase, DNA helicases, DNA clamps and DNA ... DNA Topoisomerases Prevent DNA Tangling During Replication Reece RJ, Maxwell A (26 September 2008). "DNA gyrase: structure and ... DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA ...
The potency of novobiocin is considerably higher than that of the fluoroquinolones that also target DNA gyrase, but at a ... X-ray crystallographic studies have found that the drug-receptor complex of Novobiocin and DNA Gyrase shows that ATP and ... Aminocoumarins are very potent inhibitors of bacterial DNA gyrase and work by targeting the GyrB subunit of the enzyme involved ... Lewis RJ, Tsai FT, Wigley DB (August 1996). "Molecular mechanisms of drug inhibition of DNA gyrase". BioEssays. 18 (8): 661-71 ...
... does not bind to DNA gyrase but does bind to the substrate DNA. A review in 2001 suggests that cytotoxicity of ... "Mechanism of inhibition of DNA gyrase by analogues of nalidixic acid: the target of the drugs is DNA". Proceedings of the ... It functions by inhibiting DNA gyrase, a type II topoisomerase, and topoisomerase IV, enzymes necessary to separate bacterial ... Drlica K, Zhao X (September 1997). "DNA gyrase, topoisomerase IV, and the 4-quinolones". Microbiology and Molecular Biology ...
Drlica K, Zhao X (September 1997). "DNA gyrase, topoisomerase IV, and the 4-quinolones". Microbiology and Molecular Biology ... Cinoxacin mode of action involves the inhibiting of DNA gyrase, a type II topoisomerase, and topoisomerase iv, which is an ... the older gyrase-inhibitors such as cinoxacin are no longer indicated. Cinoxacin is one of the original quinolone drugs, which ... enzyme necessary to separate replicated DNA, thereby inhibiting cell division. Within the most recent package insert (c. 1999) ...
"DNA gyrase, topoisomerase IV, and the 4-quinolones". Microbiol. Mol. Biol. Rev. 61 (3): 377-92. doi:10.1128/mmbr.61.3.377- ... 2 protein core L Klevan, JC Wang - Biochemistry, 1980 - ACS Publications Stabilization of Z-DNA by polyarginine near ... Wiley Online Library 31P NMR studies of the solution structure and dynamics of nucleosomes and DNA L Klevan, IM Armitage, DM ... Klevan acted as president of Applied Markets for ABI which produced and marketed reagent kits for forensic DNA, paternity ...
It functions by inhibiting DNA gyrase, a type II topoisomerase, and topoisomerase IV, enzymes necessary to separate bacterial ... Drlica K, Zhao X (September 1997). "DNA gyrase, topoisomerase IV, and the 4-quinolones". Microbiology and Molecular Biology ... It usually kills bacteria by blocking their ability to duplicate DNA. Moxifloxacin was patented in 1988 and approved for use in ... DNA, thereby inhibiting cell replication. About 52% of an oral or intravenous dose of moxifloxacin is metabolized via ...
It functions by inhibiting two bacterial type II topoisomerases, DNA gyrase and topoisomerase IV. Topoisomerase IV is an enzyme ... Drlica K, Zhao X (September 1997). "DNA gyrase, topoisomerase IV, and the 4-quinolones". Microbiology and Molecular Biology ... It works by interfering with the bacterium's DNA. Ofloxacin was patented in 1980 and approved for medical use in 1985. It is on ... necessary to separate (mostly in prokaryotes, in bacteria in particular) replicated DNA, thereby inhibiting bacterial cell ...
It functions by inhibiting DNA gyrase, a type II topoisomerase, and topoisomerase IV, enzymes necessary to separate bacterial ... 3, 1988 Drlica K, Zhao X (September 1997). "DNA gyrase, topoisomerase IV, and the 4-quinolones". Microbiology and Molecular ... Quinolone induced DNA damage was first reported in 1986 (Hussy et al.). Recent studies have demonstrated a correlation between ... There continues to be considerable debate as to whether or not this DNA damage is to be considered one of the mechanisms of ...
It functions by inhibiting DNA gyrase, a type II topoisomerase, and topoisomerase IV, which is an enzyme necessary to separate ... Drlica K, Zhao X (1 September 1997). "DNA gyrase, topoisomerase IV, and the 4-quinolones". Microbiol Mol Biol Rev. 61 (3): 377- ... replicated DNA, thereby inhibiting cell division. Tendinitis and rupture, usually of the Achilles tendon, are class-effects of ...
DNA gyrase, on the other hand, is responsible for supercoiling the DNA, so that it will fit in the newly formed cells. Both ... Drlica K, Zhao X (1 September 1997). "DNA gyrase, topoisomerase IV, and the 4-quinolones". Microbiol Mol Biol Rev. 61 (3): 377- ... Like all quinolones, it functions by inhibiting the DNA gyrase and topoisomerase IV, two bacterial type IIA topoisomerases. ... This enantiomer binds more effectively to the DNA gyrase enzyme and to topoisomerase IV than its (+)-(R)-counterpart. ...
Ashiuchi, M.; Kuwana, E; Yamamoto, T; Komatsu, K; Soda, K; Misono, H (2002). "Glutamate Racemase is an Endogenous DNA Gyrase ... Racemization and DNA gyrase inhibition are two independent activities of the enzyme". Microbiology. 154 (9): 2796-803. doi: ... Deprez, E.; Tauc, P.; Leh, H.; Mouscadet, J.-F.; Auclair, C.; Hawkins, M. E.; Brochon, J.-C. (2001). "DNA binding induces ... Streaker, Emily D.; Beckett, Dorothy (1998). "Coupling of Site-Specific DNA Binding to Protein Dimerization in Assembly of the ...
Its main target is the ATPase site of the DNA Gyrase GyrB subunit. Chemically induced dimerization Heide L (2009). "Genetic ... Vanden Broeck A, McEwen AG, Chebaro Y, Potier N, Lamour V (April 2019). "Structural Basis for DNA Gyrase Interaction with ...
Their affinity for gyrase is considerably higher than that of modern fluoroquinolones, which also target DNA gyrase but at the ... Aminocoumarin is a class of antibiotics that act by an inhibition of the DNA gyrase enzyme involved in the cell division in ... X-ray crystallography studies have confirmed binding at the ATP-binding site located on the gyrB subunit of DNA gyrase. ... Galm, Ute, Heller, Stefanie, Shapiro, Stuart, Page, Malcolm, Li, Shu-Ming, Heide, Lutz Antimicrobial and DNA Gyrase-Inhibitory ...
The antibiotic works by inhibiting the enzyme DNA gyrase. It also acts as a dopamine reuptake inhibitor and has stimulant ...
It accomplishes this by inhibiting DNA gyrase, and thereby preventing the replication of chloroplast DNA. As such it plays a ... As a DNA gyrase inhibitor, albicindin also has potential therapeutic use as an antibiotic. Its antibiotic properties were ... Hashimi, Saeed Mujahid (2019). "Albicidin, a potent DNA gyrase inhibitor with clinical potential". The Journal of Antibiotics. ... "The Phytotoxin Albicidin is a Novel Inhibitor of DNA Gyrase". Antimicrobial Agents and Chemotherapy. 51 (1): 181-187. doi: ...
"Inhibition of translesion DNA polymerase by archaeal reverse gyrase". Nucleic Acids Research. 37 (13): 4287-4295. doi:10.1093/ ... Using DNA-DNA hybridization, the total DNA-DNA relatedness of the two organisms was found to be 34.6 percent which, along with ... Reverse gyrase is theorized to keep the genome stable and prevent damage by the extreme heat. Along with the ability to fix ... Analysis of this gene demonstrated that this organism shared 97.8 percent of its DNA for this gene with the related bacterium ...
ParD forms a dimer and also regulates its own promoter (parDE). As with CcdB the toxin target is DNA gyrase. Induction of ParE ... ParD is a plasmid anti-toxin that forms a ribbon-helix-helix DNA binding structure. It stabilises plasmids by inhibiting ParE ... ParD of plasmid RK2 consists of two structurally distinct moieties and belongs to the ribbon-helix-helix family of DNA-binding ...
... is a bactericidal drug that inhibits bacterial DNA gyrase and topoisomerase IV. Like other quinolones and ... "Mechanism of action of quinolones against Escherichia coli DNA gyrase". Antimicrobial Agents and Chemotherapy. 37 (4): 839-45. ... fluoroquinolones the compound eradicates bacteria by interfering with DNA replication (bacterial DNA replication, transcription ...
Like other fluoroquinolones, enoxacin functions by inhibiting bacterial DNA gyrase and topoisomerase IV. The inhibition of ... "Mechanism of action of quinolones against Escherichia coli DNA gyrase". Antimicrobial Agents and Chemotherapy. 37 (4): 839-845 ... Quinolones and fluoroquinolones are bactericidal drugs, eradicating bacteria by interfering with DNA replication. ... these enzymes prevents bacterial DNA replication, transcription, repair and recombination. Recently, it was shown that Enoxacin ...
Quinolones inhibit the bacterial DNA gyrase or the topoisomerase IV enzyme, thereby inhibiting DNA replication and ... For many gram-negative bacteria DNA gyrase is the target, whereas topoisomerase IV is the target for many gram-positive ... Eukaryotic cells do not contain DNA gyrase or topoisomerase IV. Quinolones Psaty BM (December 2008). "Clinical trial design and ...
"New Antibacterial Agents Derived from the DNA Gyrase Inhibitor Cyclothialidine". Journal of Medicinal Chemistry. 47 (6): 1487- ...
Yamashiro, K.; Yamagishi, A. (2005). "Characterization of the DNA Gyrase from the Thermoacidophilic Archaeon Thermoplasma ...
Kampranis SC, Bates AD, Maxwell A (July 1999). "A model for the mechanism of strand passage by DNA gyrase". Proc. Natl. Acad. ... It appears that Hsp90 can act as a "protector" of less stable proteins produced by DNA mutations. Hsp90 is also required for ... Once in the nucleus, the GR dimerizes and binds to specific sequences of DNA and thereby upregulates the expression of GR ... Gyrase, Hsp90, Histidine Kinase, MutL) superfamily. A common binding pocket for ATP and the inhibitor geldanamycin is situated ...
Like other quinolone antibiotics, ozenoxacin targets DNA gyrase and topoisomerase IV. Its activity against bacteria with ...
... is an aminocoumarin antibacterial that inhibits the enzyme DNA gyrase. [1], http://www.drugbank.ca/drugs/DB03966. ...
It has the same mechanism of action as fluouroquinolones; it inhibits DNA gyrase, preventing DNA synthesis, gene duplication, ...
"Posttranslational modifications in microcin B17 define an additional class of DNA gyrase inhibitor". Proc Natl Acad Sci U S A. ... His work defined an origin of DNA replication that led to the development of many suicide cloning vectors still in use today. ... Finkel, S. E.; Kolter, R. (November 2001). "DNA as a nutrient: novel role for bacterial competence gene homologs". Journal of ... Kolter, R; Helinski, DR (1982). "Plasmid R6K DNA replication. II. Direct nucleotide sequence repeats are required for an active ...
Mutations in DNA gyrase are commonly associated with antibiotic resistance in P. aeruginosa. These mutations, when combined ... which protects DNA gyrase and topoisomerase IV from the effects of quinolone (fluoroquinolone) antibiotics such as ... LigDs form a subfamily of the DNA ligases. These all have a LigDom/ligase domain, but many bacterial LigDs also have separate ... September 2015). "Pel is a cationic exopolysaccharide that cross-links extracellular DNA in the Pseudomonas aeruginosa biofilm ...
Upon binding to DNA (the "Gyrase-DNA" state), there is a competition between DNA wrapping and dissociation, where increasing ... whose single circular DNA is cut by DNA gyrase and the two ends are then twisted around each other to form supercoils. Gyrase ... DNA gyrase, or simply gyrase, is an enzyme within the class of topoisomerase and is a subclass of Type II topoisomerases that ... DNA cleavage and reunion is performed by a catalytic center located in DNA-gates build by all gyrase subunits. C-gates are ...
DNA in intracellular Salmonella enterica serovar Typhimurium relaxes during growth in the acidified (pH 4-5) macrophage vacuole ... Inhibiting ATP binding by DNA gyrase and topo IV with novobiocin enhanced the effect of low pH on DNA relaxation. Bacteria ... Negative supercoiling of DNA by gyrase is inhibited in Salmonella enterica serovar Typhimurium during adaptation to acid stress ... Negative supercoiling of DNA by gyrase is inhibited in Salmonella enterica serovar Typhimurium during adaptation to acid stress ...
DNA gyrase subunit B (Escherichia coli K-12). Find diseases associated with this biological target and compounds tested against ...
Inhibition of wild type Escherichia coli DNA gyrase subunit A2B2 at 100 uM using relaxed pBR322 DNA as substrate incubated for ...
companies, pharmaceutical R&D and research hospitals worldwide in life sciences and drug discovery ...
E. coli DNA Gyrase, Topo IV, S. aureus DNA Gyrase, Topo IV TopoGEN offers powerful and tractable services to identify Gyrase ... Cell Context DNA Repair *Homologous Recombination Reporter Cells *Human: HeLa Reporter Cell Line (Includes I-Sce1 Transfection) ... Cell Context DNA Repair *Homologous Recombination Reporter Cells *Human: HeLa Reporter Cell Line (Includes I-Sce1 Transfection) ...
Order S aureus Gyrase DNA Supercoiling Assay Plus 01014298341 at Gentaur S. aureus Gyrase DNA Supercoiling Plus ... S. aureus Gyrase DNA Supercoiling Assay Plus includes 500 µl of 10 x Buffer T2, 410 µl of 10 x relaxed DNA, 22 µl of 1500 x H19 ... Reagents for fluorescence-based 384-well or 96-well assays of S. aureus gyrase DNA supercoiling activity, 100 assays. ... dye, 450 µl of 10 x ATP, 43 µl 7.5 uM S. aureus gyrase, 820 µl of 2 M potassium glutamate and 3000 µl of 10 x H19 dilution ...
keywords = "Catalysis, DNA Gyrase/chemistry, DNA, Superhelical/chemistry, DNA-Binding Proteins/chemistry, Escherichia coli/ ... N2 - Bacterial DNA gyrase introduces negative supercoils into chromosomal DNA and relaxes positive supercoils introduced by ... AB - Bacterial DNA gyrase introduces negative supercoils into chromosomal DNA and relaxes positive supercoils introduced by ... Bacterial DNA gyrase introduces negative supercoils into chromosomal DNA and relaxes positive supercoils introduced by ...
Gellert, M., Mizuuchi, K., ODea, M.H., Nash, H.A. DNA gyrase: an enzyme that introduces superhelical turns into DNA. ... Staphylococcus aureus will be stopped by DNA gyrB inhibition. The study employs DNA gyrase as its target and provides ... Cozzarelli, N.R. DNA gyrase and the supercoiling of DNA. Science. 1980;207(4434):953-960. ... Phytochemical analysis and antibacterial activity of traditional plants for the inhibition of DNA gyrase Authors. * Rajakumari ...
DNA gyrase is a therapeutic target used in the design and development of new antibacterial agents. Selective antibacterial ... Objective: The aim of this study is to elucidate mode of action for existing DNA gyrase inhibitors and to pave the way towards ... Methods: In this study, the mechanism of action for selected DNA gyrase inhibitors available was carried out through molecular ... Computational Insight into the Mechanism of Action of DNA Gyrase Inhibitors; Revealing a New Mechanism ...
The targets of quinolone activity are the bacterial DNA gyrase and topoisomerase IV, enzymes essential for DNA replication and ... Quinolones inhibit two enzymes that are required for bacterial DNA synthesis, i.e., DNA gyrase and topoisomerase IV. Resistance ...
... possessing inhibitory activity against DNA gyrase. In the present paper, a detailed biophysical characterization of this ... we have demonstrated that compound 1 binds reversibly to the ATP-binding site of the 24 kDa N-terminal fragment of DNA gyrase B ... the competitive inhibitory mechanism with respect to ATP and forms a useful basis for further development of potent DNA gyrase ... DNA gyrase represents a validated antibacterial target and has drawn much interest in recent years. By a structure-based ...
Dive into the research topics of The C-terminal domain of DNA gyrase A adopts a DNA-bending β-pinwheel fold. Together they ... The C-terminal domain of DNA gyrase A adopts a DNA-bending β-pinwheel fold. ...
Synthesis, antimicrobial evaluation, DNA gyrase inhibition, and in silico pharmacokinetic studies of novel quinoline ... Synthesis, antimicrobial evaluation, DNA gyrase inhibition, and in silico pharmacokinetic studies of novel quinoline ... Herein, we report the synthesis and in vitro antimicrobial evaluation of novel quinoline derivatives as DNA gyrase inhibitors. ... A subsequent in vitro investigation against the bacterial DNA gyrase target enzyme revealed a significant potent inhibitory ...
Topoisomerases are assuming crucial elements of DNA metabolism5. Quinolones conflict with the motion of DNA gyrase, a critical ... mutation in DNA gyrase (type II Topoisomerase) which is essential enzyme contributory in chromosomal DNA replication and ... which can be crucial compounds in arrange the topological condition of DNA via its replication and transcription. DNA gyrase is ... The Role of DNA Gyrase (gyrA) in Ciprofloxacin-Resistant Locally Isolates Pseudomonas aeruginosa in Al-Khadhmiya Teaching ...
Rapid, DNA-induced subunit exchange by DNA gyrase Thomas Germe, Natassja G. Bush ... Anthony Maxwell ... Mitochondrial DNA: Are some mutations more equal than others? Auden Cote-LHeureux, Yogesh NK Maithania ... Konstantin Khrapko ... Drosophila macrophages control systemic cytokine levels in response to oxidative stress via a non-canonical DNA damage repair ... colonization factors of the honey bee gut symbiont Frischella perrara and are regulated by the conserved histone-like DNA- ...
Conserved Protein Domain Family DNA_gyraseB_C, The amino terminus of eukaryotic and prokaryotic DNA topoisomerase II are ... DNA gyrase B subunit, carboxyl terminus. The amino terminus of eukaryotic and prokaryotic DNA topoisomerase II are similar, but ... The amino-terminal portion of the DNA gyrase B protein is thought to catalyze the ATP-dependent super-coiling of DNA. See ... The carboxyl-terminal end supports the complexation with the DNA gyrase A protein and the ATP-independent relaxation. This ...
Moxifloxacin inhibits the A subunits of DNA gyrase, resulting in inhibition of bacterial DNA replication and transcription. It ... It inhibits bacterial growth by inhibiting DNA gyrase. It is indicated for superficial ocular infections of the conjunctiva or ...
... he is studying the repair pathway centered on tyrosyl-DNA-phosphodiesterases (TDP1 and TDP2) and poly(ADP-ribose)polymerases ( ... which emphasizes new approaches to cancer treatments targeting DNA, epigenetic and chromatin, and connected biomarkers. ... Pommier is a leader on DNA topoisomerase biology and biochemistry, and their cancer relevance. He revealed the interfacial ... Exonuclease VII repairs quinolone-induced damage by resolving DNA gyrase cleavage complexes. Huang, S.-y.N., Michaels, S.A., ...
The site of action is bacterial gyrase, a synthesis promoting enzyme. The effect on Escherichia coli is the inhibition of DNA ... Quinolone carboxylic acid derivatives are classified as DNA gyrase inhibitors. The mechanism of action of these compounds is ... Dougherty, T.J., & Saukkonenn, J.J. (1985). Membrane permeability changes associated with DNA gyrase inhibitors in Escherichia ... synthesis through prevention of DNA supercoiling. Among other things, such compounds lead to the cessation of cell respiration ...
Mechanochemistry of DNA Gyrase - a processive molecular motor 24 November (Tuesday). 2.30 PM FB 382. ...
Drlica, K., and Zhao, X. (1997). DNA gyrase, topoisomerase IV, and the 4-quinolones. Microbiol. Mol. Biol. Rev. 61, 377-392. ... Ciprofloxacin is a fluoroquinolone interfering with bacterial replication via inhibition of the enzymes DNA gyrase and ... Sreedharan, S., Oram, M., Jensen, B., Peterson, L., and Fisher, L. (1990). DNA gyrase gyrA mutations in ciprofloxacin-resistant ... due to amino acid changes in the DNA gyrase GyrA (Ser84Leu) and topoisomerase IV GrlA (Ser80Tyr), encoded by gyrA and grlA ...
Levofloxacin inhibits DNA gyrase and topoisomerase IV, resulting in bactericidal activity. It is used as an alternative agent ...
DNA gyrase - only in? is? and does what?. Definition. Prokaryotes, Topoisomerase, unwinds 1 coil and reforms with ... DNA repair system (4 steps!). Definition. 1. recognize deformity in DNA. 2. generate gap in DNA. 3. fill gap with DNA ... DNA polymerase requires a ?. And adds what to that?. Definition. RNA primer. Catalyzed by a primer. Adds deoxyribonucleotides ... DNA Polymerase copies template in what direction? Synthesizes new strand in what direction?. ...
DNA mismatch repair protein, C-terminal domain. ENSORLP00000018914. PF13589. 1e-11. HATPase_c_3. Histidine kinase-, DNA gyrase ... DNA mismatch repair protein, C-terminal. ENSORLP00000018914. ProSitePatterns. PS00058. IPR014762. 98. 104. -. DNA mismatch ... DNA mismatch repair protein family. ENSORLP00000018914. Pfam. PF00505. IPR009071. 552. 613. 4.00e-11. High mobility group box ...
DNA Gyrase. Relieves strain of unwinding by DNA helicase; this is a specific type of topoisomerase ... Provides a starting point of RNA (or DNA) for DNA polymerase to begin synthesis of the new DNA strand. ... Bind to ssDNA and prevent the DNA double helix from re-annealing after DNA helicase unwinds it, thus maintaining the strand ... DNA clamp. பொலிமரேசு நொதியம் பிரிந்து செலவதைத் தடுக்கும் நொதியம் Single-Strand Binding (SSB) Proteins. ...
The target of the quinolones is a DNA gyrase. Ofloxacin and ciprofloxacin are compounds in this family that are licensed for ... Clofazimine inhibits mycobacterial growth and binds preferentially to mycobacterial DNA causing inhibition of transcription. In ...
  • Two classes of antibiotics that inhibit gyrase are: The aminocoumarins (including novobiocin and Coumermycin A1), which work by competitive inhibition of energy transduction of DNA gyrase by binding to the ATPase active site on the GyrB subunit. (wikipedia.org)
  • One of these hypothesis suggests the inhibition of subunit A of DNA-gyrase in presence of ATP [ 5 - 7 ]. (hindawi.com)
  • Thus, inhibition of the negative supercoiling activity of gyrase was the primary cause of enhanced DNA relaxation in drug-treated bacteria. (jic.ac.uk)
  • Staphylococcus aureus will be stopped by DNA gyrB inhibition. (biomedicineonline.org)
  • The molecular docking and MD simulation results revealed that compound 14 could act by inhibiting gyrase A. A pharmacophore model that consisted of the features that would help the inhibition effect was generated. (sdu.edu.tr)
  • Synthesis, antimicrobial evaluation, DNA gyrase inhibition, and in silico pharmacokinetic studies of novel quinoline derivatives. (olmdiagnostics.com)
  • Compounds that revealed the best activity were subjected to further biological studies to determine their minimum inhibitory concentrations (MICs) against the selected pathogens as well as their in vitro activity against the E. coli DNA gyrase, to realize whether their antimicrobial action is mediated via inhibition of this enzyme. (olmdiagnostics.com)
  • Several researches have been exhibited that mutations imparting fluoroquinolone resistance in P. aeruginosa may attributed to amendment in DNA gyrase, hypothesizing that faded sensitivity to fluoroquinolone result from inhibition of DNA supercoiling in resistant isolates of Gram-negative pathogens and alteration in gyrA consider leading causes in this resistance 7 . (microbiologyjournal.org)
  • Moxifloxacin inhibits the A subunits of DNA gyrase, resulting in inhibition of bacterial DNA replication and transcription. (medscape.com)
  • The effect on Escherichia coli is the inhibition of DNA synthesis through prevention of DNA supercoiling. (drugs.com)
  • Their bactericidal and bacteriostatic properties result from inhibition of the enzyme DNA gyrase. (aafp.org)
  • Recently, high throughput mapping of DNA gyrase sites in the Escherichia coli genome using Topo-Seq approach revealed a long (≈130 bp) and degenerate binding motif that can explain the existence of SGSs. (wikipedia.org)
  • To address how gyrase copes with these topological challenges, we used high-speed single-molecule fluorescence imaging in live Escherichia coli cells. (york.ac.uk)
  • Using mass spectrometry, NMR spectroscopy, and fluorescence experiments we have demonstrated that compound 1 binds reversibly to the ATP-binding site of the 24 kDa N-terminal fragment of DNA gyrase B from Escherichia coli (GyrB24) with low micromolar affinity. (hal.science)
  • In this study, we investigated the presence of plasmid-mediated quinolone resistance (PMQR) genes among 101 ciprofloxacin-resistant urinary Escherichia coli isolates and searched for mutations in the quinolone-resistance-determining regions (QRDRs) of the DNA gyrase and topoisomerase IV genes in PMQR-carrying isolates. (scielo.br)
  • Hence, novel gyrase inhibitors with novel mechanisms are required. (sdu.edu.tr)
  • Objective: The aim of this study is to elucidate mode of action for existing DNA gyrase inhibitors and to pave the way towards discovery of novel inhibitors. (sdu.edu.tr)
  • Methods: In this study, the mechanism of action for selected DNA gyrase inhibitors available was carried out through molecular docking and molecular dynamics (MD) simulation. (sdu.edu.tr)
  • In addition, pharmacophore analysis, density functional theory (DFT) calculations, and computational pharmacokinetics analysis of the gyrase inhibitors were performed. (sdu.edu.tr)
  • Results: This study demonstrated that all the DNA gyrase inhibitors investigated, except compound 14, exhibit their activity by inhibiting gyrase B at a binding pocket. (sdu.edu.tr)
  • Conclusion: In this study, mode of action elucidation through molecular docking and MD simulation, pharmacophore model generation, pharmacokinetic property prediction, and DFT study for selected DNA gyrase inhibitors were carried out. (sdu.edu.tr)
  • The outcomes of this study are anticipated to contribute to the design of novel gyrase inhibitors. (sdu.edu.tr)
  • The predicted binding mode explains the competitive inhibitory mechanism with respect to ATP and forms a useful basis for further development of potent DNA gyrase inhibitors. (hal.science)
  • Herein, we report the synthesis and in vitro antimicrobial evaluation of novel quinoline derivatives as DNA gyrase inhibitors. (olmdiagnostics.com)
  • To understand the determinants of response to topoisomerase inhibitors, he is studying the repair pathway centered on tyrosyl-DNA-phosphodiesterases (TDP1 and TDP2) and poly(ADP-ribose)polymerases (PARP). (cancer.gov)
  • Dr. Pommier conceptualized the "interfacial inhibitors" mechanism based on his finding that DNA topoisomerase inhibitors act by trapping topoisomerase-DNA complexes (Capranico et al. (cancer.gov)
  • Quinolone carboxylic acid derivatives are classified as DNA gyrase inhibitors. (drugs.com)
  • They found out that green tea catechins inhibit essential bacterial enzyme DNA gyrase, which is the target of several existing clinically used drugs. (sciencedaily.com)
  • Ciprofloxacin inhibits bacterial DNA synthesis by binding to gyrase. (medscape.com)
  • It inhibits bacterial growth by inhibiting DNA gyrase. (medscape.com)
  • Levofloxacin inhibits DNA gyrase and topoisomerase IV, resulting in bactericidal activity. (medscape.com)
  • Inhibits bacterial DNA gyrase (topoisomerase). (enzolifesciences.com)
  • Thus, it seems that this protein binds to gyrase and inhibits its activity by mimicking DNA. (ne.jp)
  • In this study, the activity of medicinal compounds to inhibit DNA gyrB is explored. (biomedicineonline.org)
  • Phytochemical screening was performed to study the medication options that could inhibit DNA gyrB. (biomedicineonline.org)
  • Quinolones inhibit two enzymes that are required for bacterial DNA synthesis, i.e. (cdc.gov)
  • Inhibit DNA gyrase in bacterial cells. (flashcardmachine.com)
  • Quinolones inhibit the bacterial DNA synthesis [ 2 ], and there are several hypotheses to explain their mechanism of action. (hindawi.com)
  • The targets of quinolone activity are the bacterial DNA gyrase and topoisomerase IV, enzymes essential for DNA replication and transcription. (cdc.gov)
  • Quinolones has the ability to sort kind two topoisomerases, which can be crucial compounds in arrange the topological condition of DNA via its replication and transcription. (microbiologyjournal.org)
  • The ability of gyrase (and topoisomerase IV) to relax positive supercoils allows superhelical tension ahead of the polymerase to be released so that replication can continue. (wikipedia.org)
  • E. coli DNA Gyrase, Topo IV, S. aureus DNA Gyrase, Topo IV TopoGEN offers powerful and tractable services to identify Gyrase and Topoisomerase IV targeting antibiotics. (topogen.com)
  • DNA gyrase and topoisomerase IV. (cdc.gov)
  • It functions by inhibiting DNA gyrase , a type II topoisomerase , and topoisomerase IV, [5] which is an enzyme necessary to separate, replicated DNA, thereby inhibiting cell division. (wikidoc.org)
  • Quinolone resistance among Enterobacteriaceae originally occurred due to chromosomal mutations in the quinolone-resistance-determining regions (QRDRs) of the gyrA and gyrB genes, which encode the gyrase A and B subunits, respectively and the parC and parE genes, which encode topoisomerase IV subunits (Hernández et al. (scielo.br)
  • The amino-terminal portion of the DNA gyrase B protein is thought to catalyze the ATP-dependent super-coiling of DNA. (nih.gov)
  • The carboxyl-terminal end supports the complexation with the DNA gyrase A protein and the ATP-independent relaxation. (nih.gov)
  • Therefore, molecular docking was also used in the present study to simulate the binding of cordycepin with different antibacterial targets, such as β-ketoacyl-(acyl-carrier-protein) synthase III (FabH), DNA gyrase B and thymidylate kinase, in order to identify the most likely antimicrobial mechanism of cordycepin. (spandidos-publications.com)
  • Streptomyces-produced quinolone and coumarin antibiotics, such as novobiocin, interfere with a protein called gyrase that assists in the normal separation of double-stranded DNA during replication of DNA or transcription of messenger RNA. (icr.org)
  • The CcdB protein (poison) is cytotoxic and poisons DNA-gyrase complexes. (igem.org)
  • Tse, Y.C., Wang, J.C. E. coli and M. luteus DNA topoisomerase I can catalyze catenation or decatenation of double-stranded DNA rings. (biomedicineonline.org)
  • The number of superhelical turns introduced into an initially relaxed circular DNA has been calculated to be approximately equal to the number of ATP molecules hydrolyzed by gyrase. (wikipedia.org)
  • DNA gyrase is a tetrameric enzyme that consists of 2 GyrA ("A") and 2 GyrB ("B") subunits. (wikipedia.org)
  • DNA cleavage and reunion is performed by a catalytic center located in DNA-gates build by all gyrase subunits. (wikipedia.org)
  • According to the catalytic cycle proposed, binding of 2 ATP molecules causes dimerization of ATPase domains of GyrB subunits and capturing of a T-segment of DNA (T- from transferring) in a cavity between GyrB subunits. (wikipedia.org)
  • The two regions correspond to DNA binding by C-terminal domains of GyrA subunits and resemble eukaryotic nucleosome binding motif. (wikipedia.org)
  • By a structure-based approach we have previously discovered compound 1, an indolinone derivative, possessing inhibitory activity against DNA gyrase. (hal.science)
  • A subsequent in vitro investigation against the bacterial DNA gyrase target enzyme revealed a significant potent inhibitory activity of quinoline derivative 14, which can be observed from its IC50 value (3.39 μM). (olmdiagnostics.com)
  • Which have ability to interfered with the bacterial DNA gyrase, it has bactericidal activity with a wide spectrum in opposition to Gram positive and Gram-negative microorganism 2 . (microbiologyjournal.org)
  • S. aureus Gyrase DNA Supercoiling Assay Plus includes 500 µl of 10 x Buffer T2, 410 µl of 10 x relaxed DNA, 22 µl of 1500 x H19 dye, 450 µl of 10 x ATP, 43 µl 7.5 uM S. aureus gyrase, 820 µl of 2 M potassium glutamate and 3000 µl of 10 x H19 dilution buffer. (assaydes.com)
  • A single molecule study has characterized gyrase activity as a function of DNA tension (applied force) and ATP, and proposed a mechanochemical model. (wikipedia.org)
  • The Salmonella cytosol reaches pH 5-6 in response to an external pH of 4-5: the ATP-dependent DNA supercoiling activity of purified gyrase was progressively inhibited by lowering the pH in this range, as was the ATP-dependent DNA relaxation activity of topo IV. (jic.ac.uk)
  • We propose that DNA relaxation in Salmonella within macrophage is due to acid-mediated impairment of the negative supercoiling activity of gyrase. (jic.ac.uk)
  • The research focuses on the discovery of novel plant-based therapeutic compounds to target DNA gyrase B activity. (biomedicineonline.org)
  • The goal of the study is to identify innovative plant-based medicinal molecules that specifically target DNA gyrase B activity. (biomedicineonline.org)
  • Also, a molecular docking study of the most active compounds was carried out to explore the binding affinity of the new ligands toward the active site of DNA gyrase enzyme as a proposed target of their activity. (olmdiagnostics.com)
  • by inhibiting the activity of DNA gyrase and topoisomerase, enzymes essential for bacterial DNA replication. (msdmanuals.com)
  • Wang, J.C. Cellular roles of DNA topoisomerases: a molecular perspective. (biomedicineonline.org)
  • The results of computational molecular docking analysis indicated that the interaction energy between cordycepin and NAD+‑dependent DNA ligase (LigA) was lower than that between cordycepin and other common antibacterial targets. (spandidos-publications.com)
  • Rapid molecular identification and typing methods that may be useful include 16S rRNA gene sequencing, random amplified polymorphic DNA and a combination polymerase chain reaction-restriction fragment length polymorphism analysis ( 39 , 116 ). (antimicrobe.org)
  • Molecular Evolution of the Pseudomonas aeruginosa DNA Gyrase gyrA Gene. (bvsalud.org)
  • As the result of a catalytic cycle two ATP molecules are hydrolyzed and two negative supercoils are introduced into the DNA template. (wikipedia.org)
  • Therefore, it can be suggested that two ATP molecules are hydrolyzed per cycle of reaction by gyrase, leading to the introduction of a linking difference of -2. (wikipedia.org)
  • Gyrase is present in prokaryotes and some eukaryotes, but the enzymes are not entirely similar in structure or sequence, and have different affinities for different molecules. (wikipedia.org)
  • We demonstrate that at least 300 gyrase molecules are stably bound to the chromosome at any time, with ~12 enzymes enriched near each replication fork. (york.ac.uk)
  • Dwell times of ~2 s were observed for the dispersed gyrase molecules, which we propose maintain steady-state levels of negative supercoiling of the chromosome. (york.ac.uk)
  • Bacteria expressing novobiocin-resistant (NovR) derivatives of gyrase or topo IV also exhibited DNA relaxation at acid pH, although further relaxation with novobiocin was not seen in the strain with NovRgyrase. (jic.ac.uk)
  • Biophysical characterization of an indolinone inhibitor in the ATP-binding site of DNA gyrase. (hal.science)
  • RFLP-PCR showed that out of 17 isolates resistant to Ciprofloxacin mutation inDNA gyrase (GyrA) were detected in six (35.2 %) isolated while the reminder 11 (64.7%) has no mutation. (microbiologyjournal.org)
  • DNA gyrase, or simply gyrase, is an enzyme within the class of topoisomerase and is a subclass of Type II topoisomerases that reduces topological strain in an ATP dependent manner while double-stranded DNA is being unwound by elongating RNA-polymerase or by helicase in front of the progressing replication fork. (wikipedia.org)
  • DNA gyrase is a class of Type II Topoisomerases that plays an important role in bacterial viability. (biomedicineonline.org)
  • Topoisomerases are assuming crucial elements of DNA metabolism 5 . (microbiologyjournal.org)
  • He was the first to show that topoisomerases are trapped by DNA damage (by oxidative base lesions, base alkylation, DNA nicks) (Pourquier et al. (cancer.gov)
  • Recently, Dr. Pommier demonstrated that misincorporated ribonucleotides (the most frequent DNA alteration) trap topoisomerases, which convert them to toxic and mutagenic nicks by TOP1 (Kim et al. (cancer.gov)
  • 2018). While studying the tyrosyl-DNA-phosphodiesterase (TDP1 and TDP2) repair pathways for the excision of topoisomerases from DNA, Dr. Pommier revealed that TDP1 repairs a broad range of 3'-blocking lesions in addition to TOP1 (Murai et al. (cancer.gov)
  • The ability of gyrase to relax positive supercoils comes into play during DNA replication and prokaryotic transcription. (wikipedia.org)
  • Bacterial DNA gyrase introduces negative supercoils into chromosomal DNA and relaxes positive supercoils introduced by replication and transiently by transcription. (york.ac.uk)
  • Removal of these positive supercoils is essential for replication fork progression and for the overall unlinking of the two duplex DNA strands, as well as for ongoing transcription. (york.ac.uk)
  • It is found in all bacteria and is involved in replication, repair, recombination, and DNA transcription. (biomedicineonline.org)
  • Dr. Pommier also discovered that the natural compound, ecteinascidin 743 (commercialized as Yondelis) and its analog trabectedin acts by alkylating DNA and killing cancer cells by trapping transcription-coupled nucleotide excision repair (TC-NER) (Takebayashi et al, Nature Med 2001). (cancer.gov)
  • It will be simpler to do a follow-up study on discovering bioactive compounds and evaluating their effectiveness in inhibiting DNA gyrB with the help of this preliminary data from the analytical procedures. (biomedicineonline.org)
  • Up to now several compounds targeted against the ATP-binding site of bacteria gyrase have been known but couldn't be used as drugs due to their side effects on mammalian cells. (sciencedaily.com)
  • Another hypothesis supports the existence of a cooperative bond between the quinolone-DNA-DNA-gyrase [ 8 - 11 ]. (hindawi.com)
  • This makes gyrase a good target for antibiotics. (wikipedia.org)
  • Antibiotics are used to select all types of plasmidic vectors in bacteria which is a significant concern in industrial cultures producing recombinant proteins or DNA. (igem.org)
  • It is the only known enzyme to actively contribute negative supercoiling to DNA, while it also is capable of relaxing positive supercoils. (wikipedia.org)
  • The helical nature of the DNA causes positive supercoils to accumulate ahead of a translocating enzyme, in the case of DNA replication, a DNA polymerase. (wikipedia.org)
  • Inhibiting ATP binding by DNA gyrase and topo IV with novobiocin enhanced the effect of low pH on DNA relaxation. (jic.ac.uk)
  • DNA gyrase is made from two A and B fragments, these fragments encoded through the gyrA and gyrB genes 4 . (microbiologyjournal.org)
  • Quinolones conflict with the motion of DNA gyrase, a critical bacterial kind II DNA topoisomerase 6 . (microbiologyjournal.org)
  • The study employs DNA gyrase as its target and provides information on potential therapeutic targets. (biomedicineonline.org)
  • DNA gyrase is a therapeutic target used in the design and development of new antibacterial agents. (sdu.edu.tr)
  • Gyrase is also found in eukaryotic plastids: it has been found in the apicoplast of the malarial parasite Plasmodium falciparum and in chloroplasts of several plants. (wikipedia.org)
  • The amino terminus of eukaryotic and prokaryotic DNA topoisomerase II are similar, but they have a different carboxyl terminus. (nih.gov)
  • Eukaryotic DNA polymerases? (flashcardmachine.com)
  • 4] Failure of DNA to properly separate during these processes results in a bacterium not being able to divide normally or produce functional proteins. (icr.org)
  • Since the antidote is unstable and degraded by a host protease, the poison will be free and able to poison DNA-gyrase complexes. (igem.org)
  • Strong gyrase binding sites (SGS) were found in some phages (bacteriophage Mu group) and plasmids (pSC101, pBR322). (wikipedia.org)
  • These species were validated primarily on the basis of DNA-DNA hybridization, 16S rRNA gene sequence analysis, antimicrobial susceptibility and biochemical profiles, and, to a lesser degree, on high-performance liquid chromatography ( 22 , 54 , 55 , 69 ). (antimicrobe.org)
  • DNA in intracellular Salmonella enterica serovar Typhimurium relaxes during growth in the acidified (pH 4-5) macrophage vacuole and DNA relaxation correlates with the upregulation of Salmonella genes involved in adaptation to the macrophage environment. (jic.ac.uk)
  • The study focuses on DNA gyrase as a target and shows insights into future drug development. (biomedicineonline.org)
  • DNA gyrase represents a validated antibacterial target and has drawn much interest in recent years. (hal.science)
  • By the use of NMR spectroscopy, researchers from Slovenia have now pinpointed the ATP-binding site of DNA gyrase as target of EGCG, the most abundant catechin from the green tea extract. (sciencedaily.com)
  • It contains two periodic regions in which GC-rich islands are alternated with AT-rich patches by a period close to the period of DNA double helix (≈10.5 bp). (wikipedia.org)
  • Results from circular dichroism and denaturation of calf thymus DNA (CT-DNA) suggested that increased amounts of copper complex were able to stabilize the double helix of DNA in vitro mainly by formation of hydrogen bonds between chn and the sugars of DNA minor groove. (hindawi.com)
  • This process occurs in bacteria, whose single circular DNA is cut by DNA gyrase and the two ends are then twisted around each other to form supercoils. (wikipedia.org)
  • The unique ability of gyrase to introduce negative supercoils into DNA at the expense of ATP hydrolysis is what allows bacterial DNA to have free negative supercoils. (wikipedia.org)
  • Structurally the complex is formed by 3 pairs of "gates", sequential opening and closing of which results into the direct transfer of DNA segment and introduction of 2 negative supercoils. (wikipedia.org)
  • Negative supercoiling of DNA by gyrase is inhibited in Salmonella enterica serovar Typhimurium during adaptation to acid stress. (jic.ac.uk)
  • Negative supercoiling of bacterial DNA by DNA gyr B is essential in replication which further influences all the metabolic activities. (biomedicineonline.org)