Quorum Sensing
4-Butyrolactone
Homoserine
Gene Expression Regulation, Bacterial
Chromobacterium
Carbon-Sulfur Lyases
Lactones
Pseudomonas aeruginosa
Biofilms
Vibrio
Aliivibrio fischeri
Virulence
Virulence Factors
Trans-Activators
Farnesol
Serratia
Pectobacterium
Burkholderia
Furans
Signal Transduction
Ligases
Repressor Proteins
Transition to quorum sensing in an Agrobacterium population: A stochastic model. (1/1065)
Understanding of the intracellular molecular machinery that is responsible for the complex collective behavior of multicellular populations is an exigent problem of modern biology. Quorum sensing, which allows bacteria to activate genetic programs cooperatively, provides an instructive and tractable example illuminating the causal relationships between the molecular organization of gene networks and the complex phenotypes they control. In this work we--to our knowledge for the first time--present a detailed model of the population-wide transition to quorum sensing using the example of Agrobacterium tumefaciens. We construct a model describing the Ti plasmid quorum-sensing gene network and demonstrate that it behaves as an "on-off" gene expression switch that is robust to molecular noise and that activates the plasmid conjugation program in response to the increase in autoinducer concentration. This intracellular model is then incorporated into an agent-based stochastic population model that also describes bacterial motion, cell division, and chemical communication. Simulating the transition to quorum sensing in a liquid medium and biofilm, we explain the experimentally observed gradual manifestation of the quorum-sensing phenotype by showing that the transition of individual model cells into the "on" state is spread stochastically over a broad range of autoinducer concentrations. At the same time, the population-averaged values of critical autoinducer concentration and the threshold population density are shown to be robust to variability between individual cells, predictable and specific to particular growth conditions. Our modeling approach connects intracellular and population scales of the quorum-sensing phenomenon and provides plausible answers to the long-standing questions regarding the ecological and evolutionary significance of the phenomenon. Thus, we demonstrate that the transition to quorum sensing requires a much higher threshold cell density in liquid medium than in biofilm, and on this basis we hypothesize that in Agrobacterium quorum sensing serves as the detector of biofilm formation. (+info)Regulation of Mycobacterium tuberculosis whiB3 in the mouse lung and macrophages. (2/1065)
Mycobacterium tuberculosis is a highly successful human pathogen, with approximately 2x10(9) individuals infected globally. To understand the responses of M. tuberculosis to the in vivo environment, we studied the in vivo regulation of M. tuberculosis genes whose M. marinum homologs are induced in chronically infected frog tissues. The expression of 16S rRNA was shown to remain constant in M. tuberculosis under in vivo and in vitro conditions and therefore could be used for internal normalization in quantitative reverse transcription-PCR assays. We found whiB3, a putative transcriptional regulator implicated in mediating tissue damage, to be maximally induced at 2 weeks postinfection in the lungs of wild-type and immunodeficient (gamma interferon receptor-/-, Rag1-/-, and tumor necrosis factor alpha-/-) mice. At later time points in wild-type mice, whiB3 induction was decreased and gradually declined over the course of infection. In immunodeficient mice, whiB3 induction declined rapidly and was completely abolished in moribund animals. whiB3 was also found to be induced in naive bone marrow-derived macrophages after 6 h of infection. whiB3 expression in vivo and in vitro was found to be inversely correlated with bacterial density. These results indicate that M. tuberculosis regulates the expression of whiB3 in response to environmental signals present in vivo and are consistent with a model of regulation by quorum sensing. (+info)Structure-activity analysis of quorum-sensing signaling peptides from Streptococcus mutans. (3/1065)
Streptococcus mutans secretes and utilizes a 21-amino-acid signaling peptide pheromone to initiate quorum sensing for genetic competence, biofilm formation, stress responses, and bacteriocin production. In this study, we designed and synthesized a series of truncated peptides and peptides with amino acid substitutions to investigate their structure-activity relationships based on the three-dimensional structures of S. mutans wild-type signaling peptide UA159sp and C-terminally truncated peptide TPC3 from mutant JH1005 defective in genetic competence. By analyzing these peptides, we demonstrated that the signaling peptide of S. mutans has at least two functional domains. The C-terminal structural motif consisting of a sequence of polar hydrophobic charged residues is crucial for activation of the signal transduction pathway, while the core alpha-helical structure extending from residue 5 to the end of the peptide is required for receptor binding. Peptides in which three or more residues were deleted from the C terminus did not induce genetic competence but competitively inhibited quorum sensing activated by UA159sp. Disruption of the amphipathic alpha-helix by replacing the Phe-7, Phe-11, or Phe-15 residue with a hydrophilic residue resulted in a significant reduction in or complete loss of the activity of the peptide. In contrast to the C-terminally truncated peptides, these peptides with amino acid substitutions did not compete with UA159sp to activate quorum sensing, suggesting that disruption of the hydrophobic face of the alpha-helical structure results in a peptide that is not able to bind to the receptor. This study is the first study to recognize the importance of the signaling peptide C-terminal residues in streptococcal quorum sensing. (+info)Novel Pseudomonas aeruginosa quorum-sensing inhibitors identified in an ultra-high-throughput screen. (4/1065)
The opportunistic pathogen Pseudomonas aeruginosa has two complete acyl-homoserine lactone (acyl-HSL) signaling systems, LasR-LasI and RhlR-RhlI. LasI catalyzes the synthesis of N-3-oxododecanoyl homoserine lactone (3OC12-HSL), and LasR is a transcription factor that requires 3OC12-HSL as a ligand. RhlI catalyzes the synthesis of N-butanoyl homoserine lactone (C4), and RhlR is a transcription factor that responds to C4. LasR and RhlR control the transcription of hundreds of P. aeruginosa genes, many of which are critical virulence determinants, and LasR is required for RhlR function. We developed an ultra-high-throughput cell-based assay to screen a library of approximately 200,000 compounds for inhibitors of LasR-dependent gene expression. Although the library contained a large variety of chemical structures, the two best inhibitors resembled the acyl-homoserine lactone molecule that normally binds to LasR. One compound, a tetrazole with a 12-carbon alkyl tail designated PD12, had a 50% inhibitory concentration (IC50) of 30 nM. The second compound, V-06-018, had an IC50 of 10 microM and is a phenyl ring with a 12-carbon alkyl tail. A microarray analysis showed that both compounds were general inhibitors of quorum sensing, i.e., the expression levels of most LasR-dependent genes were affected. Both compounds also inhibited the production of two quorum-sensing-dependent virulence factors, elastase and pyocyanin. These compounds should be useful for studies of LasR-dependent gene regulation and might serve as scaffolds for the identification of new quorum-sensing modulators. (+info)Revised model for Enterococcus faecalis fsr quorum-sensing system: the small open reading frame fsrD encodes the gelatinase biosynthesis-activating pheromone propeptide corresponding to staphylococcal agrd. (5/1065)
Gelatinase biosynthesis-activating pheromone (GBAP) is an autoinducing peptide involved in Enterococcus faecalis fsr quorum sensing, and its 11-amino-acid sequence has been identified in the C-terminal region of the 242-residue deduced fsrB product (J. Nakayama et al., Mol. Microbiol. 41:145-154, 2001). In this study, however, we demonstrated the existence of fsrD, encoding the GBAP propeptide, which is in frame with fsrB but is translated independently of fsrB. It was also demonstrated that FsrB', an FsrD segment-truncated FsrB, functions as a cysteine protease-like processing enzyme to generate GBAP from FsrD. This revised model is consistent with the staphylococcal agr system. (+info)Differentiation between electron transport sensing and proton motive force sensing by the Aer and Tsr receptors for aerotaxis. (6/1065)
Aerotaxis (oxygen-seeking) behaviour in Escherichia coli is a response to changes in the electron transport system and not oxygen per se. Because changes in proton motive force (PMF) are coupled to respiratory electron transport, it is difficult to differentiate between PMF, electron transport or redox, all primary candidates for the signal sensed by the aerotaxis receptors, Aer and Tsr. We constructed electron transport mutants that produced different respiratory H+/e- stoichiometries. These strains expressed binary combinations of one NADH dehydrogenase and one quinol oxidase. We then introduced either an aer or tsr mutation into each mutant to create two sets of electron transport mutants. In vivo H+/e- ratios for strains grown in glycerol medium ranged from 1.46+/-0.18-3.04+/-0.47, but rates of respiration and growth were similar. The PMF jump in response to oxygen was proportional to the H+/e- ratio in each set of mutants (r2=0.986-0.996). The length of Tsr-mediated aerotaxis responses increased with the PMF jump (r2=0.988), but Aer-mediated responses did not correlate with either PMF changes (r2=0.297) or the rate of electron transport (r2=0.066). Aer-mediated responses were linked to NADH dehydrogenase I, although there was no absolute requirement. The data indicate that Tsr responds to changes in PMF, but strong Aer responses to oxygen are associated with redox changes in NADH dehydrogenase I. (+info)Role of bacteriocin immunity proteins in the antimicrobial sensitivity of Streptococcus mutans. (7/1065)
Bacteria utilize quorum-sensing systems to modulate environmental stress responses. The quorum-sensing system of Streptococcus mutans is mediated by the competence-stimulating peptide (CSP), whose precursor is encoded by the comC gene. A comC mutant of strain GS5 exhibited enhanced antimicrobial sensitivity to a wide variety of different agents. Since the addition of exogenous CSP did not complement this phenotype, it was determined that the increased tetracycline, penicillin, and triclosan sensitivities resulted from repression of the putative bacteriocin immunity protein gene, bip, which is located immediately upstream from comC. We further demonstrated that the inactivation of bip or smbG, another bacteriocin immunity protein gene present within the smb operon in S. mutans GS5, affected sensitivity to a variety of antimicrobial agents. Furthermore, both the bip and smbG genes were upregulated in the presence of low concentrations of antibiotics and were induced during biofilm formation relative to in planktonic cells. These results suggest, for the first time, that the antimicrobial sensitivity of a bacterium can be modulated by some of the putative bacteriocin immunity proteins expressed by the organism. The implications of these observations for the evolution of bacteriocin immunity protein genes as well as for potential new chemotherapeutic strategies are discussed. (+info)Crystal structure and mechanism of TraM2, a second quorum-sensing antiactivator of Agrobacterium tumefaciens strain A6. (8/1065)
Quorum sensing is a community behavior that bacteria utilize to coordinate a variety of population density-dependent biological functions. In Agrobacterium tumefaciens, quorum sensing regulates the replication and conjugative transfer of the tumor-inducing (Ti) plasmid from pathogenic strains to nonpathogenic derivatives. Most of the quorum-sensing regulatory proteins are encoded within the Ti plasmid. Among these, TraR is a LuxR-type transcription factor playing a key role as the quorum-sensing signal receptor, and TraM is an antiactivator that antagonizes TraR through the formation of a stable oligomeric complex. Recently, a second TraM homologue called TraM2, not encoded on the Ti plasmid of A. tumefaciens A6, was identified, in addition to a copy on the Ti plasmid. In this report, we have characterized TraM2 and its interaction with TraR and solved its crystal structure to 2.1 A. Like TraM, TraM2 folds into a helical bundle and exists as homodimer. TraM2 forms a stable complex (K(d) = 8.6 nM) with TraR in a 1:1 binding ratio, a weaker affinity than that of TraM for TraR. Structural analysis and biochemical studies suggest that protein stability may account for the difference between TraM2 and TraM in their binding affinities to TraR and provide a structural basis for L54 in promoting structural stability of TraM. (+info)Quorum sensing is a type of cell-cell communication that allows bacteria to detect and respond to changes in population density by producing, releasing, and responding to signaling molecules called autoinducers. This process enables the coordinated expression of certain genes related to various group behaviors such as biofilm formation, virulence factor production, and bioluminescence. The term "quorum sensing" was coined in 1994 by Bonnie L. Bassler and Susan Goldberg to describe this population-dependent gene regulation mechanism in bacteria.
4-Butyrolactone, also known as gamma-butyrolactone (GBL) or 1,4-butanolide, is a chemical compound with the formula C4H6O2. It is a colorless oily liquid that is used in various industrial and commercial applications, including as an intermediate in the production of other chemicals, as a solvent, and as a flavoring agent.
In the medical field, 4-butyrolactone has been studied for its potential use as a sleep aid and muscle relaxant. However, it is not currently approved by regulatory agencies such as the US Food and Drug Administration (FDA) for these uses. It is also known to have abuse potential and can cause intoxication, sedation, and other central nervous system effects when ingested or inhaled.
It's important to note that 4-butyrolactone is not a medication and should only be used under the supervision of a qualified healthcare professional for approved medical purposes.
Acyl-butyrolactones are a type of chemical compound that consists of a butyrolactone ring (a five-membered ring containing an oxygen atom and a carbonyl group) that has an acyl group (a functional group consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to another functional group) attached to it.
Butyrolactones are lactones, which are cyclic esters derived from carboxylic acids. The addition of an acyl group to the butyrolactone ring results in the formation of acyl-butyrolactones. These compounds have a variety of uses in organic synthesis and may also be found in some natural sources.
It's worth noting that "acyl-butyrolactones" is a general term that can refer to any compound with this basic structure, and there may be many specific compounds that fall under this category. Therefore, it's important to consult a detailed chemical reference or speak with a chemist for more information on a specific acyl-butyrolactone compound.
Homoserine is not a medical term per se, but rather a chemical compound with relevance to biochemistry and molecular biology. Homoserine is an amino acid that is not commonly encoded by DNA in the genetic code of organisms, but it can be formed through the metabolic pathways of certain amino acids. Specifically, homoserine is a non-proteinogenic amino acid that can be produced from the intermediate metabolite of methionine and threonine catabolism. It plays a crucial role in the biosynthesis of various essential compounds, such as certain amino acids and antibiotics.
While homoserine is not directly related to medical conditions or treatments, understanding its biochemical properties can contribute to broader knowledge about metabolic pathways, genetic regulation, and molecular biology, which may have implications for various areas of medicine, including pharmacology, genetics, and microbiology.
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.
'Chromobacterium' is a genus of gram-negative, aerobic or facultatively anaerobic bacteria that are commonly found in soil and water. The name "Chromobacterium" comes from the Greek words "chroma," meaning color, and "bakterion," meaning rod or staff. This refers to the fact that many species of this genus produce pigments that give them distinctive colors.
One of the most well-known species in this genus is Chromobacterium violaceum, which produces a characteristic violet-colored pigment called violacein. This bacterium can cause serious infections in humans, particularly in people with weakened immune systems. Other species in the genus include Chromobacterium aquaticum, Chromobacterium haemolyticum, and Chromobacterium piscinae, among others.
Chromobacterium species are known to be resistant to a variety of antibiotics, which can make them difficult to treat in clinical settings. They have also been studied for their potential industrial applications, such as the production of enzymes and other biomolecules with commercial value.
Carbon-sulfur lyases are a class of enzymes that catalyze the cleavage of carbon-sulfur bonds in organic compounds, resulting in the formation of a new double bond. These enzymes play important roles in various biological processes, including the metabolism of sulfur-containing amino acids and the biosynthesis of certain cofactors and secondary metabolites.
Carbon-sulfur lyases are classified under EC number 4.4.1, which includes enzymes that catalyze the formation of carbon-carbon bonds by means other than those involving oxidoreductases. Within this class, carbon-sulfur lyases are further divided into several subcategories based on their specific reaction mechanisms and substrate specificities.
One example of a carbon-sulfur lyase is cysteine desulfurase (EC 2.8.1.7), which catalyzes the formation of alanine and a persulfide group from L-cysteine, releasing elemental sulfur as a byproduct. This enzyme plays a critical role in the biosynthesis of iron-sulfur clusters, which are essential cofactors for many proteins involved in electron transfer reactions.
Another example is 3-mercaptopyruvate sulfurtransferase (EC 2.8.1.2), which catalyzes the formation of a persulfide group on a cysteine residue in the enzyme itself, using 3-mercaptopyruvate as a sulfur donor. This enzyme is involved in the biosynthesis of various secondary metabolites containing sulfur atoms, such as allicin in garlic and penicillamine in certain fungi.
Overall, carbon-sulfur lyases are important enzymes that play critical roles in various biological processes involving the cleavage or formation of carbon-sulfur bonds.
Lactones are not a medical term per se, but they are important in the field of pharmaceuticals and medicinal chemistry. Lactones are cyclic esters derived from hydroxy acids. They can be found naturally in various plants, fruits, and some insects. In medicine, lactones have been used in the synthesis of drugs, including certain antibiotics and antifungal agents. For instance, the penicillin family of antibiotics contains a beta-lactone ring in their structure, which is essential for their antibacterial activity.
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.
"Pseudomonas aeruginosa" is a medically important, gram-negative, rod-shaped bacterium that is widely found in the environment, such as in soil, water, and on plants. It's an opportunistic pathogen, meaning it usually doesn't cause infection in healthy individuals but can cause severe and sometimes life-threatening infections in people with weakened immune systems, burns, or chronic lung diseases like cystic fibrosis.
P. aeruginosa is known for its remarkable ability to resist many antibiotics and disinfectants due to its intrinsic resistance mechanisms and the acquisition of additional resistance determinants. It can cause various types of infections, including respiratory tract infections, urinary tract infections, gastrointestinal infections, dermatitis, and severe bloodstream infections known as sepsis.
The bacterium produces a variety of virulence factors that contribute to its pathogenicity, such as exotoxins, proteases, and pigments like pyocyanin and pyoverdine, which aid in iron acquisition and help the organism evade host immune responses. Effective infection control measures, appropriate use of antibiotics, and close monitoring of high-risk patients are crucial for managing P. aeruginosa infections.
Biofilms are defined as complex communities of microorganisms, such as bacteria and fungi, that adhere to surfaces and are enclosed in a matrix made up of extracellular polymeric substances (EPS). The EPS matrix is composed of polysaccharides, proteins, DNA, and other molecules that provide structural support and protection to the microorganisms within.
Biofilms can form on both living and non-living surfaces, including medical devices, implants, and biological tissues. They are resistant to antibiotics, disinfectants, and host immune responses, making them difficult to eradicate and a significant cause of persistent infections. Biofilms have been implicated in a wide range of medical conditions, including chronic wounds, urinary tract infections, middle ear infections, and device-related infections.
The formation of biofilms typically involves several stages, including initial attachment, microcolony formation, maturation, and dispersion. Understanding the mechanisms underlying biofilm formation and development is crucial for developing effective strategies to prevent and treat biofilm-associated infections.
"Vibrio" is a genus of Gram-negative, facultatively anaerobic, curved-rod bacteria that are commonly found in marine and freshwater environments. Some species of Vibrio can cause diseases in humans, the most notable being Vibrio cholerae, which is the causative agent of cholera, a severe diarrheal illness. Other pathogenic species include Vibrio vulnificus and Vibrio parahaemolyticus, which can cause gastrointestinal or wound infections. These bacteria are often transmitted through contaminated food or water and can lead to serious health complications, particularly in individuals with weakened immune systems.
Bacterial physiological phenomena refer to the various functional processes and activities that occur within bacteria, which are necessary for their survival, growth, and reproduction. These phenomena include:
1. Metabolism: This is the process by which bacteria convert nutrients into energy and cellular components. It involves a series of chemical reactions that break down organic compounds such as carbohydrates, lipids, and proteins to produce energy in the form of ATP (adenosine triphosphate).
2. Respiration: This is the process by which bacteria use oxygen to convert organic compounds into carbon dioxide and water, releasing energy in the form of ATP. Some bacteria can also perform anaerobic respiration, using alternative electron acceptors such as nitrate or sulfate instead of oxygen.
3. Fermentation: This is a type of anaerobic metabolism in which bacteria convert organic compounds into simpler molecules, releasing energy in the form of ATP. Unlike respiration, fermentation does not require an external electron acceptor.
4. Motility: Many bacteria are capable of moving independently, using various mechanisms such as flagella or twitching motility. This allows them to move towards favorable environments and away from harmful ones.
5. Chemotaxis: Bacteria can sense and respond to chemical gradients in their environment, allowing them to move towards attractants and away from repellents.
6. Quorum sensing: Bacteria can communicate with each other using signaling molecules called autoinducers. When the concentration of autoinducers reaches a certain threshold, the bacteria can coordinate their behavior, such as initiating biofilm formation or producing virulence factors.
7. Sporulation: Some bacteria can form spores, which are highly resistant to heat, radiation, and chemicals. Spores can remain dormant for long periods of time and germinate when conditions are favorable.
8. Biofilm formation: Bacteria can form complex communities called biofilms, which are composed of cells embedded in a matrix of extracellular polymeric substances (EPS). Biofilms can provide protection from environmental stressors and host immune responses.
9. Cell division: Bacteria reproduce by binary fission, where the cell divides into two identical daughter cells. This process is regulated by various cell cycle checkpoints and can be influenced by environmental factors such as nutrient availability.
'Aliivibrio fischeri' (formerly known as 'Vibrio fischeri') is a gram-negative, bioluminescent bacterium that naturally occurs in marine environments. It has the ability to form symbiotic relationships with certain marine animals, such as squid and fish, by colonizing their light organs. The bacteria provide a source of light through a process called bioluminescence, which is used by the host animal for counter-illumination camouflage, communication, or attracting prey. In return, the host animal provides nutrients to support the growth and survival of the bacteria.
The medical relevance of 'Aliivibrio fischeri' is limited, as it primarily interacts with marine organisms rather than humans. However, studying its bioluminescence system has contributed significantly to our understanding of bacterial signaling pathways, gene regulation, and host-microbe interactions.
Pyocyanin is not a medical condition, but rather a blue-green pigment produced by certain strains of the bacterium Pseudomonas aeruginosa. It is a secondary metabolite that plays a role in the pathogenesis of P. aeruginosa infections. Pyocyanin has been found to have various effects on host cells, including inducing oxidative stress, inhibiting chemotaxis and phagocytosis of immune cells, and modulating signaling pathways. It is often used as a marker for the presence of P. aeruginosa in clinical samples and research settings.
Virulence, in the context of medicine and microbiology, refers to the degree or severity of damage or harm that a pathogen (like a bacterium, virus, fungus, or parasite) can cause to its host. It is often associated with the ability of the pathogen to invade and damage host tissues, evade or suppress the host's immune response, replicate within the host, and spread between hosts.
Virulence factors are the specific components or mechanisms that contribute to a pathogen's virulence, such as toxins, enzymes, adhesins, and capsules. These factors enable the pathogen to establish an infection, cause tissue damage, and facilitate its transmission between hosts. The overall virulence of a pathogen can be influenced by various factors, including host susceptibility, environmental conditions, and the specific strain or species of the pathogen.
Virulence factors are characteristics or components of a microorganism, such as bacteria, viruses, fungi, or parasites, that contribute to its ability to cause damage or disease in a host organism. These factors can include various structures, enzymes, or toxins that allow the pathogen to evade the host's immune system, attach to and invade host tissues, obtain nutrients from the host, or damage host cells directly.
Examples of virulence factors in bacteria include:
1. Endotoxins: lipopolysaccharides found in the outer membrane of Gram-negative bacteria that can trigger a strong immune response and inflammation.
2. Exotoxins: proteins secreted by some bacteria that have toxic effects on host cells, such as botulinum toxin produced by Clostridium botulinum or diphtheria toxin produced by Corynebacterium diphtheriae.
3. Adhesins: structures that help the bacterium attach to host tissues, such as fimbriae or pili in Escherichia coli.
4. Capsules: thick layers of polysaccharides or proteins that surround some bacteria and protect them from the host's immune system, like those found in Streptococcus pneumoniae or Klebsiella pneumoniae.
5. Invasins: proteins that enable bacteria to invade and enter host cells, such as internalins in Listeria monocytogenes.
6. Enzymes: proteins that help bacteria obtain nutrients from the host by breaking down various molecules, like hemolysins that lyse red blood cells to release iron or hyaluronidases that degrade connective tissue.
Understanding virulence factors is crucial for developing effective strategies to prevent and treat infectious diseases caused by these microorganisms.
Trans-activators are proteins that increase the transcriptional activity of a gene or a set of genes. They do this by binding to specific DNA sequences and interacting with the transcription machinery, thereby enhancing the recruitment and assembly of the complexes needed for transcription. In some cases, trans-activators can also modulate the chromatin structure to make the template more accessible to the transcription machinery.
In the context of HIV (Human Immunodeficiency Virus) infection, the term "trans-activator" is often used specifically to refer to the Tat protein. The Tat protein is a viral regulatory protein that plays a critical role in the replication of HIV by activating the transcription of the viral genome. It does this by binding to a specific RNA structure called the Trans-Activation Response Element (TAR) located at the 5' end of all nascent HIV transcripts, and recruiting cellular cofactors that enhance the processivity and efficiency of RNA polymerase II, leading to increased viral gene expression.
Farnesol is a chemical compound classified as a sesquiterpene alcohol. It is produced by various plants and insects, including certain types of roses and citrus fruits, and plays a role in their natural defense mechanisms. Farnesol has a variety of uses in the perfume industry due to its pleasant, floral scent.
In addition to its natural occurrence, farnesol is also synthetically produced for use in various applications, including as a fragrance ingredient and as an antimicrobial agent in cosmetics and personal care products. It has been shown to have antibacterial and antifungal properties, making it useful for preventing the growth of microorganisms in these products.
Farnesol is not typically used as a medication or therapeutic agent in humans, but it may have potential uses in the treatment of certain medical conditions due to its antimicrobial and anti-inflammatory properties. However, more research is needed to fully understand its effects and safety profile in these contexts.
"Serratia" is a genus of Gram-negative, facultatively anaerobic, motile bacilli that are commonly found in the environment, such as in water and soil. Some species, particularly "Serratia marcescens," can cause healthcare-associated infections, including pneumonia, urinary tract infections, wound infections, and bloodstream infections. These infections often occur in patients with compromised immune systems or who have been hospitalized for extended periods of time. Serratia species are resistant to multiple antibiotics, which can make treatment challenging.
"Vibrio cholerae" is a species of gram-negative, comma-shaped bacteria that is the causative agent of cholera, a diarrheal disease. It can be found in aquatic environments, such as estuaries and coastal waters, and can sometimes be present in raw or undercooked seafood. The bacterium produces a toxin called cholera toxin, which causes the profuse, watery diarrhea that is characteristic of cholera. In severe cases, cholera can lead to dehydration and electrolyte imbalances, which can be life-threatening if not promptly treated with oral rehydration therapy or intravenous fluids.
Pectobacterium is a genus of gram-negative, rod-shaped bacteria that are facultative anaerobes, meaning they can grow with or without oxygen. These bacteria are known to cause soft rot diseases in a wide range of plants, including important crops such as potatoes and vegetables. They produce pectinases, enzymes that break down pectin, a major component of plant cell walls, leading to maceration and decay of plant tissues.
Some notable species of Pectobacterium include:
* Pectobacterium carotovorum (formerly Erwinia carotovora), which is known to cause soft rot in many vegetables, fruits, and ornamental plants.
* Pectobacterium atrosepticum (formerly Erwinia carotovora subsp. atroseptica), which primarily causes blackleg and soft rot diseases in potatoes.
* Pectobacterium wasabiae (formerly Erwinia wasabiae), which is associated with wasabi root rot.
Pectobacterium spp. are typically motile, having a single polar flagellum or multiple lateral flagella. They can survive in soil, water, and plant debris, and can be disseminated through infected seeds, contaminated tools, and irrigation water. Infections caused by Pectobacterium can lead to significant economic losses in agriculture due to reduced crop yield and quality.
Burkholderia is a genus of gram-negative, rod-shaped bacteria that are widely distributed in the environment, including soil, water, and associated with plants. Some species of Burkholderia are opportunistic pathogens, meaning they can cause infection in individuals with weakened immune systems or underlying medical conditions.
One of the most well-known species of Burkholderia is B. cepacia, which can cause respiratory infections in people with cystic fibrosis and chronic granulomatous disease. Other notable species include B. pseudomallei, the causative agent of melioidosis, a potentially serious infection that primarily affects the respiratory system; and B. mallei, which causes glanders, a rare but severe disease that can affect humans and animals.
Burkholderia species are known for their resistance to many antibiotics, making them difficult to treat in some cases. Proper identification of the specific Burkholderia species involved in an infection is important for determining the most appropriate treatment approach.
Furans are not a medical term, but a class of organic compounds that contain a four-membered ring with four atoms, usually carbon and oxygen. They can be found in some foods and have been used in the production of certain industrial chemicals. Some furan derivatives have been identified as potentially toxic or carcinogenic, but the effects of exposure to these substances depend on various factors such as the level and duration of exposure.
In a medical context, furans may be mentioned in relation to environmental exposures, food safety, or occupational health. For example, some studies have suggested that high levels of exposure to certain furan compounds may increase the risk of liver damage or cancer. However, more research is needed to fully understand the potential health effects of these substances.
It's worth noting that furans are not a specific medical condition or diagnosis, but rather a class of chemical compounds with potential health implications. If you have concerns about exposure to furans or other environmental chemicals, it's best to consult with a healthcare professional for personalized advice and recommendations.
Signal transduction is the process by which a cell converts an extracellular signal, such as a hormone or neurotransmitter, into an intracellular response. This involves a series of molecular events that transmit the signal from the cell surface to the interior of the cell, ultimately resulting in changes in gene expression, protein activity, or metabolism.
The process typically begins with the binding of the extracellular signal to a receptor located on the cell membrane. This binding event activates the receptor, which then triggers a cascade of intracellular signaling molecules, such as second messengers, protein kinases, and ion channels. These molecules amplify and propagate the signal, ultimately leading to the activation or inhibition of specific cellular responses.
Signal transduction pathways are highly regulated and can be modulated by various factors, including other signaling molecules, post-translational modifications, and feedback mechanisms. Dysregulation of these pathways has been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.
Ligases are a group of enzymes that catalyze the formation of a covalent bond between two molecules, usually involving the joining of two nucleotides in a DNA or RNA strand. They play a crucial role in various biological processes such as DNA replication, repair, and recombination. In DNA ligases, the enzyme seals nicks or breaks in the phosphodiester backbone of the DNA molecule by catalyzing the formation of an ester bond between the 3'-hydroxyl group and the 5'-phosphate group of adjacent nucleotides. This process is essential for maintaining genomic integrity and stability.
Repressor proteins are a type of regulatory protein in molecular biology that suppress the transcription of specific genes into messenger RNA (mRNA) by binding to DNA. They function as part of gene regulation processes, often working in conjunction with an operator region and a promoter region within the DNA molecule. Repressor proteins can be activated or deactivated by various signals, allowing for precise control over gene expression in response to changing cellular conditions.
There are two main types of repressor proteins:
1. DNA-binding repressors: These directly bind to specific DNA sequences (operator regions) near the target gene and prevent RNA polymerase from transcribing the gene into mRNA.
2. Allosteric repressors: These bind to effector molecules, which then cause a conformational change in the repressor protein, enabling it to bind to DNA and inhibit transcription.
Repressor proteins play crucial roles in various biological processes, such as development, metabolism, and stress response, by controlling gene expression patterns in cells.
Pseudomonas infections are infections caused by the bacterium Pseudomonas aeruginosa or other species of the Pseudomonas genus. These bacteria are gram-negative, opportunistic pathogens that can cause various types of infections, including respiratory, urinary tract, gastrointestinal, dermatological, and bloodstream infections.
Pseudomonas aeruginosa is a common cause of healthcare-associated infections, particularly in patients with weakened immune systems, chronic lung diseases, or those who are hospitalized for extended periods. The bacteria can also infect wounds, burns, and medical devices such as catheters and ventilators.
Pseudomonas infections can be difficult to treat due to the bacteria's resistance to many antibiotics. Treatment typically involves the use of multiple antibiotics that are effective against Pseudomonas aeruginosa. In severe cases, intravenous antibiotics or even hospitalization may be necessary.
Prevention measures include good hand hygiene, contact precautions for patients with known Pseudomonas infections, and proper cleaning and maintenance of medical equipment.
Pectobacterium carotovorum is a species of gram-negative, rod-shaped bacteria that are facultative anaerobes, meaning they can grow in the presence or absence of oxygen. These bacteria are known to cause soft rot diseases in a wide range of plants, including potatoes, carrots, and other vegetables. They produce pectinases, which are enzymes that break down pectin, a component of plant cell walls, leading to maceration and decay of the plant tissue.
The bacteria can enter the plant through wounds or natural openings, such as stomata, and spread systemically throughout the plant. They can survive in soil, water, and plant debris, and can be disseminated through contaminated seeds, tools, and equipment. The diseases caused by Pectobacterium carotovorum can result in significant economic losses for farmers and the produce industry.
In humans, Pectobacterium carotovorum is not considered a pathogen and does not cause disease. However, there have been rare cases of infection associated with contaminated food or water, which can lead to gastrointestinal symptoms such as diarrhea, nausea, and vomiting. These infections are typically self-limiting and do not require antibiotic treatment.
Quorum sensing
Interspecies quorum sensing
S-ribosylhomocysteine lyase
Autoinducer-2
Roberto Kolter
4,5-Dihydroxy-2,3-pentanedione
Bonnie Bassler
Arabidopsis
Bacteria
Cell signaling
Autoinducer
Dysbiosis
Pseudomonas aeruginosa
Burkholderia cenocepacia
Marine holobiont
Lactonase
Holobiont
Pseudomonas coronafaciens
Luciferase
Acyl-homoserine-lactone synthase
Swarming motility
Kordia algicida
Ajoene
Aromatic alcohol
Massilia (bacterium)
Naturally occurring phenols
Aliivibrio fischeri
Communication
Marine prokaryotes
Locus of enterocyte effacement-encoded regulator
Quorum sensing - Wikipedia
Quorum Sensing News, Research
Cooperation and conflict in quorum-sensing bacterial populations | Nature
Quorum sensing and microbial biofilms
How Quorum Sensing Works
Cranberry-derived proanthocyanidins impair virulence and inhibit quorum sensing of Pseudomonas aeruginosa | Scientific Reports
quorum sensing Archives - Transactions on NanoBioscience (TNB)
Quorum sensing in vibrio cholerae - microbewiki
Trends in Quorum Sensing and Quorum Quenching | New Perspectives and A
Electrochemical detection of Pseudomonas aeruginosa quorum sensing molecules at a liquid|liquid interface | University of...
Quorum sensing in vibrio cholerae: Difference between revisions - microbewiki
Ratiometric quorum sensing governs the trade-off between bacterial vertical and horizontal antibiotic resistance propagation |...
617g) Mechanical Properties of Pseudomonas Aeruginosa Pellicle Biofilm Formation in the Presence of Quorum Sensing Inhibitors |...
Small Things Considered: Quorum Sensing for the Mutes
6 Ways Staphylococcus Hominis Protects Skin Through Quorum Sensing | Cosmetics & Toiletries
"Dissecting regulatory mechanisms of quorum sensing pathways in Bacillu" by Patrick Hill
quorum sensing
Frontiers | TprA/PhrA Quorum Sensing System Has a Major Effect on Pneumococcal Survival in Respiratory Tract and Blood, and Its...
Effect of Cinnamon Oil on Quorum Sensing-Controlled Virulence Factors and Biofilm Formation in Pseudomonas aeruginosa | PLOS ONE
Quorum Sensing Protects Pseudomonas aeruginosa against Cheating by Other Species in a Laboratory Coculture Model
Quorum sensing och quorum quenching - Epsilon Archive for Student Projects
Prenylated Diresorcinols Inhibit Bacterial Quorum Sensing, NC DOCKS (North Carolina Digital Online Collection of Knowledge and...
Environmental Threats to the Symbiotic Relationship of Coral Reefs and Quorum Sensing | Academic Commons
A broad range quorum sensing inhibitor working through sRNA inhibition | www.ibmc.up.pt
Figures and data in Ecological feedback in quorum-sensing microbial populations can induce heterogeneous production of...
Numerical investigation of microbial quorum sensing under various flow conditions [PeerJ]
Interplay between quorum sensing and metabolism in Pseudomonas aeruginosa - Nottingham ePrints
Structural analyses of the AAA+ ATPase domain of the transcriptional regulator GtrR in the BDSF quorum-sensing system in...
SIS PUT | Wpływ quorum sensing na profil ramnolipidów produkowanych przez bakterie wyizolowane z odchodów zwierząt hodowlanych
Pseudomonas5
- N -acylhomoserine lactone (AHL)-mediated quorum sensing (QS) tightly regulates the expression of multiple virulence factors in the opportunistic pathogenic bacterium Pseudomonas aeruginosa . (nature.com)
- see Merry's post on ly-so-ge-ny in STC - are induced for propagation via SdiA-sensing of AHLs that were either produced by co-cultivated Pseudomonas bacteria or deliberately added to a pure culture. (asmblog.org)
- A cell density-dependent regulatory network termed quorum sensing (QS) is pivotal in the control of P. aeruginosa pathogenicity, and the signal molecules employed are N-acyl-L-homoserine lactones (AHLs) and the Pseudomonas quinolone signal (PQS). (nottingham.ac.uk)
- Using Pseudomonas aeruginosa PAO1 as an example of an opportunistic human pathogen, we show that a synthetic derivate of natural furanone compounds can act as a potent antagonist of bacterial quorum sensing. (montana.edu)
- All three PONs hydrolyze microbial N-acyl homoserine lactone quorum sensing factors, quenching Pseudomonas aeruginosa's pathogenesis. (cdc.gov)
Biofilm formation3
- The goal of this study is to investigate the effects of certain natural quorum sensing inhibitors on biofilm formation. (aiche.org)
- Vibrio cholerae , the Gram-negative bacterium abruptly colonizes the human intestine causing diarrhea , employing quorum sensing (QS) system as the major survival technique for mediating biofilm formation, virulence , competence , etc. (bvsalud.org)
- Quorum sensing (QS) and biofilm formation are important mechanisms related to antibiotic resistance of many pathogens. (hacettepe.edu.tr)
Inhibitors3
- The applications of quorum sensing inhibitors such as small molecules, bioactives, natural compounds, and quorum quenching enzymes in controlling bacterial infections in clinical settings, agriculture and aquaculture are discussed. (taylorfrancis.com)
- Special focus is given to exploring quorum sensing inhibitors from microbes and flora inhabiting biodiversity rich regions including tropical rain forests and marine environments. (taylorfrancis.com)
- This study correlates the activity of the quorum sensing inhibitors with viscoelastic changes in the P. aeruginosa biofilm on the air-medium interface. (aiche.org)
Bacteria27
- Many species of bacteria use quorum sensing to coordinate gene expression according to the density of their local population. (wikipedia.org)
- Quorum sensing in pathogenic bacteria activates host immune signaling and prolongs host survival, by limiting the bacterial intake of nutrients, such as tryptophan, which further is converted to serotonin. (wikipedia.org)
- As such, quorum sensing allows a commensal interaction between host and pathogenic bacteria. (wikipedia.org)
- Some of the best-known examples of quorum sensing come from studies of bacteria. (wikipedia.org)
- Bacteria use quorum sensing to regulate certain phenotype expressions, which in turn, coordinate their behaviours. (wikipedia.org)
- Certain bacteria are able to use quorum sensing to regulate bioluminescence, nitrogen fixation and sporulation. (wikipedia.org)
- Both gram-positive and gram-negative bacteria use quorum sensing, but there are some major differences in their mechanisms. (wikipedia.org)
- For the bacteria to use quorum sensing constitutively, they must possess three abilities: secretion of a signaling molecule, secretion of an autoinducer (to detect the change in concentration of signaling molecules), and regulation of gene transcription as a response. (wikipedia.org)
- Quorum sensing (QS) is a signaling mechanism that pathogenic bacteria use to communicate and synchronize the production of exofactors to attack their hosts. (embs.org)
- The book on Trends in Quorum Sensing and Quorum Quenching: New Perspectives and Applications focuses on the recent advances in the field of quorum sensing in bacteria and the novel strategies developed for quorum sensing inhibition. (taylorfrancis.com)
- The topics covered are multidisciplinary and wide-ranging,and includes quorum sensing phenomenon in pathogenic bacteria, food spoilers, and agriculturally relevant bacteria. (taylorfrancis.com)
- Quorum sensing is the mechanism bacteria use to communicate and act in groups. (asmblog.org)
- Bacteria have evolved complex systems to sense these conditions, and to trigger appropriate developmental programs to help them survive, grow, and respond in changing environments. (umass.edu)
- Bacteria both produce and sense signals about these density-dependent conditions in a process called quorum sensing. (umass.edu)
- Chapter 1 provides an introduction to the mechanisms utilized by bacteria referred to as quorum sensing. (umass.edu)
- Many species of bacteria use a cell-cell communication system called quorum sensing (QS) to coordinate group activities. (ku.edu)
- Quorum sensing is the ability of bacteria to communicate with each other and thereby exhibit a form of multicellularity. (slu.se)
- Of particular interest is quorum sensing, a form of bacterial communication known to coordinate gene expression in density dependent bacteria. (columbia.edu)
- The Quorum Sensing system was targeted as well in order to avoid the development of intrinsically antibiotic-resistant bacteria and to enhance a proper host defense. (unich.it)
- The discovery of communication systems (quorum sensing systems) regulating bacterial virulence has afforded a novel opportunity to control infectious bacteria without interfering with growth. (montana.edu)
- In a mouse pulmonary infection model, the drug inhibited quorum sensing of the infecting bacteria and promoted their clearance by the mouse immune response. (montana.edu)
- Quorum sensing is a process of chemical communication that bacteria use to monitor cell density and coordinate cooperative behaviors. (princeton.edu)
- While a single quorum-sensing system is sufficient to probe cell density, bacteria frequently use multiple quorum-sensing systems to regulate the same cooperative behaviors. (princeton.edu)
- How would you define quorum sensing in bacteria? (qualityhomeworkhelp.com)
- Watch the following video on "How Bacteria Talk", then read the link below on "Quorum Sensing" to learn more. (qualityhomeworkhelp.com)
- How can quorum sensing improve nutrient delivery to bacteria? (qualityhomeworkhelp.com)
- Quorum sensing was first identified in Vibrio harveyi and Vibrio fischeri , two bioluminescent marine bacteria, and was then identified as a highly conserved regulatory system among the Proteobacteria. (igem.org)
Signaling molecule2
- Global transcriptional regulator downstream RpfR (GtrR) is a key downstream regulator for quorum-sensing signaling molecule cis-2-dodecenoic acid (BDSF). (ntu.edu.sg)
- Destruction of the signaling molecule in stationary phase indicates that, in contrast to other quorum- sensing systems, quorum sensing in E. coli and S. typhimurium is critical for regulating behavior in the prestationary phase of growth. (princeton.edu)
Vibrio2
- Genom att studera symbiosförhållandet mellan bläckfisken Euprymna scolope och bakterien Vibrio fisheri, ökade förståelsen kring hur celldensiteten hos bakterierna ledde till det aktiverade gensvaret, vilket visade sig i en självlysande förmåga hos den typen av bakterier. (slu.se)
- Here, we combine modeling and experimental analyses of the Bacillus subtilis and Vibrio harveyi quorum-sensing networks to show that accumulation of multiple quorum-sensing systems may be driven by a facultative cheating mechanism. (princeton.edu)
Molecules7
- Quorum sensing is a type of bacterial communication that occurs via the secretion of autoinducer molecules (5). (kenyon.edu)
- Microbes that use quorum sensing constantly produce and secrete certain signaling molecules (called autoinducers or pheromones). (goecopure.com)
- Two hypotheses, termed quorum sensing (QS) and diffusion sensing (DS), have been suggested as competing explanations for why bacterial cells use the local concentration of small molecules to regulate numerous extracellular behaviours. (ox.ac.uk)
- Quorum sensing relies on extracellular signal molecules and cognate receptor pairs. (princeton.edu)
- Although it is a very heterogeneous species, all the strains tested were able to produce short chain acyl homoserine lactone (AHL) quorum sensing signal molecules. (haifa.ac.il)
- Quorum sensing is a community behaviour that enables microorganisms to communicate, perceive and monitor population density, and modulate gene expression by producing and responding to diffusible signal molecules. (igem.org)
- Reaching the critical level of quorum sensing molecules enables therefore a coordinated expression of specific genes, for example the luminescence genes in V. fischeri or the competence in S. pneumoniae. (igem.org)
Known as quorum2
- Community level coordination of gene expression is known as quorum sensing (QS). (frontiersin.org)
- Microorganisms efficiently coordinate phenotype expressions through a decision-making process known as quorum sensing (QS). (peerj.com)
Microbial quorum1
- What is microbial quorum sensing? (goecopure.com)
Microbes3
- But when it comes to communication skills, unicellular microbes are just as chatty, and studying quorum sensing (QS) in bac-teria is among the more fascinating topics in today's mi-cro-bi-o-lo-gy. (asmblog.org)
- Transcriptional regulators enable the microbes to sense and respond to environmental stimuli, by altering gene expression. (frontiersin.org)
- Microbes use quorum sensing to coordinate certain behaviors based on the local density of the bacterial population. (goecopure.com)
Quenching4
- 2020). Trends in Quorum Sensing and Quorum Quenching: New Perspectives and Applications (1st ed. (taylorfrancis.com)
- The potential use of quorum quenching enzymes for mitigating biofouling is also covered. (taylorfrancis.com)
- Also discussed here are mechanisms of quorum quenching used by organisms in quorum sensing pathways. (umass.edu)
- Quorum sensing och quorum quenching : bakteriers förmåga att kommunicera med varandra, och vägar att störa denna mekanism för att hämma infektion. (slu.se)
Bacillus1
- Next, we discuss in some detail the molecular mechanisms used by Bacillus subtilis to regulate pathways under control of the quorum response. (umass.edu)
Peptide1
- The authors determined S. hominis makes six unique auto-inducing peptide (AIP) signals that inhibit the quorum sensing system of Staphylococcus aureus . (cosmeticsandtoiletries.com)
Genes2
- We employed GeneChip microarray technology to identify furanone target genes and to map the quorum sensing regulon. (montana.edu)
- That multimer is now able to activate the quorum sensing-regulated genes by binding the Lux box. (igem.org)
Mechanisms1
- Quorum-sensing (QS) mechanisms are pivotal for microbial host adaptation. (frontiersin.org)
Aeruginosa2
- The quorum sensing property of P. aeruginosa is well documented, and its contribution to its virulence is being extensively studied. (aiche.org)
- We show that these QS-regulated antimicrobials are also critical for P. aeruginosa to prevent B. multivorans from cheating under nutrient conditions where both species require a P. aeruginosa quorum-regulated protease for growth. (ku.edu)
Behaviors1
- This microbial decision-making process called "quorum sensing (QS)" was originally understood as a cell-to-cell communication to identify conspecific population density and accomplish cooperative behaviors ( Fuqua, Winans & Greenberg, 1994 ). (peerj.com)
Staphylococcus1
- Pembentukan biofilm Staphylococcus aureus melalui 4 tahap yaitu tahap perlekatan, quorum sensing (QS), maturasi dan pelepasan, QS merupakan tahap paling penting pada proses pembentukan biofilm. (ub.ac.id)
System5
- In general, quorum sensing can function as a decision-making process in any decentralized system in which the components have: (a) a means of assessing the number of other components they interact with and (b) a standard response once a threshold number of components is detected. (wikipedia.org)
- UAB researchers, based on a collection of clinical isolates from several countries, have established a link between the cell-to-cell communication system (the quorum sensing) and the virulence and resistance phenotypes in Stenotrophomonas maltophilia. (news-medical.net)
- We demonstrate that a strain that has acquired an additional quorum-sensing system can exploit its ancestor that possesses one fewer system, but nonetheless, resume full cooperation with its kin when it is fixed in the population. (princeton.edu)
- An AHL quorum sensing system, designated PcoI/PcoR, was identified and characterized. (haifa.ac.il)
- The role of the quorum sensing system in the expression of a variety of traits was evaluated. (haifa.ac.il)
Autoinducers2
- Th e quorum-sensing model for the production of autoinducers in microbial populations. (elifesciences.org)
- Homogeneous and heterogeneous production of autoinducers in the quorum-sensing model. (elifesciences.org)
Gene1
- In biology, quorum sensing or quorum signaling (QS) is the ability to detect and respond to cell population density by gene regulation. (wikipedia.org)
Robotics1
- In addition to its function in biological systems, quorum sensing has several useful applications for computing and robotics. (wikipedia.org)
Demonstrate1
- These results demonstrate that the AHL quorum sensing in Ps. (haifa.ac.il)
Metabolism1
- The phenomenon is called quorum sensing , and is important to bacterial metabolism, growth and virulence. (qualityhomeworkhelp.com)
Bacterial infections1
- It will describe some ways we can utilize quorum sensing in the future to prevent bacterial infections by inhibiting their way of communicating. (slu.se)
Microorganisms1
- It is estimated that the vast majority of human infections are related to the biofilm in which the microorganisms reside and communicate with each other (Quorum Sensing), surviving in hostile environmental conditions. (unich.it)
Resistance1
- These observations suggested that cell density has a role in the phenotypic resistance of biofilm, that neither the drug efflux pumps tested nor quorum sensing through Chk1p contributes to resistance, and that azole drug tolerance at high cell density differs mechanistically from tolerance at low cell density. (who.int)
Bacterium1
- Quorum sensing was first reported in 1970, by Kenneth Nealson, Terry Platt, and J. Woodland Hastings, who observed what they described as a conditioning of the medium in which they had grown the bioluminescent marine bacterium Aliivibrio fischeri. (wikipedia.org)
Systems1
- The transcriptome analysis showed that the furanone drug specifically targeted quorum sensing systems and inhibited virulence factor expression. (montana.edu)
Https1
- Accessed at https://www.nottingham.ac.uk/quorum/what.htm on September 14, 2016. (qualityhomeworkhelp.com)
Antibiotics1
- Based on Dr. Bassler's research on quorum sensing, what might the "next generation" of antibiotics look like? (qualityhomeworkhelp.com)
Cells3
- To function pro-per-ly, all cells in a tissue have to know - and let their neigh-bors know - where exactly they are, which tasks they're performing right now, when it's time to dif-fer-en-ti-ate, to propagate, and also when it's time to die. (asmblog.org)
- So what they're doing with quo-rum sensing is talking to each other, counting each other, recognizing when they have the right number of cells that they should all do something as a group. (asmblog.org)
- Cells may also communicate via quorum sensing, which may in turn affect biofilm processes such as detachment. (cdc.gov)
Humans3
- Humans use their senses to determine the quality of their local environment. (umass.edu)
- Dog's do have an ability to sense when death has … This allows them to detect changes in the composition of atmospheric air, which would mean that they can predict natural disasters or gas leaks before humans notice. (majne.se)
- What does the concept of quorum sensing mean for virulence and disease in humans? (qualityhomeworkhelp.com)
Strain1
- A strain lacking CHK1 that fails to respond to the quorum-sensing molecule farnesol had the same response as did the wild type. (who.int)
Cell-cell communication1
- Quorum Sensing: Cell-Cell Communication in. (hhmi.org)
Molecular1
- The importance of understanding the symbiotic relationship between microbe's use of quorum sensing and the coral it inhabits may offer insight in how microbiological colonies promote reef health and how external toxins alter these molecular processes. (columbia.edu)