Autoinducer

Last updated

Autoinducers are signaling molecules that are produced in response to changes in cell-population density. As the density of quorum sensing bacterial cells increases so does the concentration of the autoinducer. Detection of signal molecules by bacteria acts as stimulation which leads to altered gene expression once the minimal threshold is reached. [1] [2] Quorum sensing is a phenomenon that allows both Gram-negative and Gram-positive bacteria to sense one another and to regulate a wide variety of physiological activities. Such activities include symbiosis, virulence, motility, antibiotic production, and biofilm formation. [3] Autoinducers come in a number of different forms depending on the species, but the effect that they have is similar in many cases. Autoinducers allow bacteria to communicate both within and between different species. This communication alters gene expression and allows bacteria to mount coordinated responses to their environments, in a manner that is comparable to behavior and signaling in higher organisms. Not surprisingly, it has been suggested that quorum sensing may have been an important evolutionary milestone that ultimately gave rise to multicellular life forms.

Contents

Discovery

The term "autoinduction" was first coined in 1970, when it was observed that the bioluminescent marine bacterium Vibrio fischeri produced a luminescent enzyme (luciferase) only when cultures had reached a threshold population density. [4] At low cell concentrations, V. fischeri did not express the luciferase gene. However, once the cultures had reached exponential growth phase, the luciferase gene was rapidly activated. This phenomenon was termed “autoinduction” because it involved a molecule (autoinducer) that accumulated in a growth medium and induced the synthesis of components of the luminescence system. [5] Subsequent research revealed that the actual autoinducer used by V. fischeri is an acylated homoserine lactone (AHL) signaling molecule.

Mechanism

In the most simplified quorum sensing systems, bacteria only need two components to make use of autoinducers. They need a way to produce a signal and a way to respond to that signal. These cellular processes are often tightly coordinated and involve changes in gene expression. The production of autoinducers generally increases as bacterial cell densities increase. Most signals are produced intracellularly and are subsequently secreted in the extracellular environment. Detection of autoinducers often involves diffusion back into cells and binding to specific receptors. Usually, binding of autoinducers to receptors does not occur until a threshold concentration of autoinducers is achieved. Once this has occurred, bound receptors alter gene expression either directly or indirectly. Some receptors are transcription factors themselves, while others relay signals to downstream transcription factors. In many cases, autoinducers participate in forward feedback loops, whereby a small initial concentration of an autoinducer amplifies the production of that same chemical signal to much higher levels.

Classes

Acylated homoserine lactones

Primarily produced by Gram-negative bacteria, acylated homoserine lactones (AHLs) are a class of small neutral lipid molecules composed of a homoserine lactone ring with an acyl chain. [6] AHLs produced by different species of Gram-negative bacteria vary in the length and composition of the acyl side chain, which often contains 4 to 18 carbon atoms. [7] AHLs are synthesized by AHL synthases. They diffuse in and out of cells by both passive transport and active transport mechanisms. [8] Receptors for AHLs include a number of transcriptional regulators called “R proteins,” which function as DNA binding transcription factors or sensor kinases. [9] [10]

Peptides

Gram-positive bacteria that participate in quorum sensing typically use secreted oligopeptides as autoinducers. Peptide autoinducers usually result from posttranslational modification of a larger precursor molecule. [11] In many Gram-positive bacteria, secretion of peptides requires specialized export mechanisms. For example, some peptide autoinducers are secreted by ATP-binding cassette transporters that couple proteolytic processing and cellular export. [12] Following secretion, peptide autoinducers accumulate in extracellular environments. Once a threshold level of signal is reached, a histidine sensor kinase protein of a two-component regulatory system detects it and a signal is relayed into the cell. [3] As with AHLs, the signal ultimately ends up altering gene expression. Unlike some AHLs, however, most oligopeptides do not act as transcription factors themselves.

Furanosyl borate diester

The free-living bioluminescent marine bacterium, Vibrio harveyi , uses another signaling molecule in addition to an acylated homoserine lactone. This molecule, termed Autoinducer-2 (or AI-2), is a furanosyl borate diester. [13] AI-2, which is also produced and used by a number of Gram-negative and Gram-positive bacteria, is believed to be an evolutionary link between the two major types of quorum sensing circuits. [3]

In gram-negative bacteria

As mentioned, Gram-negative bacteria primarily use acylated homoserine lactones (AHLs) as autoinducer molecules. The minimum quorum sensing circuit in Gram-negative bacteria consists of a protein that synthesizes an AHL and a second, different protein that detects it and causes a change in gene expression. [3] First identified in V. fischeri, these two such proteins are LuxI and LuxR, respectively. [14] [15] Other Gram-negative bacteria use LuxI-like and LuxR-like proteins (homologs), suggesting a high degree of evolutionary conservation. However, among Gram-negatives, the LuxI/LuxI-type circuit has been modified in different species. Described in more detail below, these modifications reflect bacterial adaptations to grow and respond to particular niche environments. [3]

Vibrio fischeri: bioluminescence

Ecologically, V. fischeri is known to have symbiotic associations with a number of eukaryotic hosts, including the Hawaiian Bobtail Squid ( Euprymna scolopes ). [16] In this relationship, the squid host maintains the bacteria in specialized light organs. The host provides a safe, nutrient rich environment for the bacteria and in turn, the bacteria provide light. Although bioluminescence can be used for mating and other purposes, in E. scolopes it is used for counter illumination to avoid predation. [17]

The autoinducer molecule used by V. fischeri is N-(3-oxohexanoyl)-homoserine lactone. [18] This molecule is produced in the cytoplasm by the LuxI synthase enzyme and is secreted through the cell membrane into the extracellular environment. [15] As is true of most autoinducers, the environmental concentration of N-(3-oxohexanoyl)-homoserine lactone is the same as the intracellular concentration within each cell. [19] N-(3-oxohexanoyl)-homoserine lactone eventually diffuses back into cells where it is recognized by LuxR once a threshold concentration (~10 μg/ml) has been reached. [18] LuxR binds the autoinducer and directly activates transcription of the luxICDABE operon. [20] This results in an exponential increase in both the production of autoinducer and in bioluminescence. LuxR bound by autoinducer also inhibits the expression of luxR, which is thought to provide a negative feedback compensatory mechanism to tightly control levels of the bioluminescence genes. [15]

Pseudomonas aeruginosa: virulence and antibiotic production

P. aeruginosa is an opportunistic human pathogen associated with cystic fibrosis. In P. aeruginosa infections, quorum sensing is critical for biofilm formation and pathogenicity. [21] P. aeruginosa contains two pairs of LuxI/LuxR homologs, LasI/LasR and RhlI, RhlR. [22] [23] LasI and RhlI are synthase enzymes that catalyze the synthesis of N-(3-oxododecanoyl)-homoserine lactone and N-(butyryl)-homoserine lactone, respectively. [24] [25] The LasI/LasR and the RhlI/RhlR circuits function in tandem to regulate the expression of a number of virulence genes. At a threshold concentration, LasR binds N-(3-oxododecanoyl)-homoserine lactone. Together this bound complex promotes the expression of virulence factors that are responsible for early stages of the infection process. [22]

LasR bound by its autoinducer also activates the expression of the RhlI/RhlR system in P. aeruginosa. [26] This causes the expression of RhlR which then binds its autoinducer, N-(butryl)-homoserine lactone. In turn, autoinducer-bound RhlR activates a second class of genes involved in later stages of infection, including genes needed for antibiotic production. [23] Presumably, antibiotic production by P. aeruginosa is used to prevent opportunistic infections by other bacterial species. N-(3-oxododecanoyl)-homoserine lactone prevents binding between N-(butryl)-homoserine lactone and its cognate regulator, RhlR. [27] It is believed that this control mechanism allows P. aeruginosa to initiate the quorum-sensing cascades sequentially and in the appropriate order so that a proper infection cycle can ensue. [3]

Other gram-negative autoinducers

In gram-positive bacteria

Whereas Gram-negative bacteria primarily use acylated homoserine lactones, Gram-positive bacteria generally use oligopeptides as autoinducers for quorum sensing. These molecules are often synthesized as larger polypeptides that are cleaved post-translationally to produce “processed” peptides. Unlike AHLs that can freely diffuse across cell membranes, peptide autoinducers usually require specialized transport mechanisms (often ABC transporters). Additionally, they do not freely diffuse back into cells, so bacteria that use them must have mechanisms to detect them in their extracellular environments. Most Gram-positive bacteria use a two-component signaling mechanism in quorum sensing. Secreted peptide autoinducers accumulate as a function of cell density. Once a quorum level of autoinducer is achieved, its interaction with a sensor kinase at the cell membrane initiates a series of phosphorylation events that culminate in the phosphorylation of a regulator protein intracellularly. [3] This regulator protein subsequently functions as a transcription factor and alters gene expression. Similar to Gram-negative bacteria, the autoinduction and quorum sensing system in Gram-positive bacteria is conserved, but again, individual species have tailored specific aspects for surviving and communicating in unique niche environments.

Streptococcus pneumoniae: competence

S. pneumoniae is human pathogenic bacterium in which the process of genetic transformation was first described in the 1930s. [33] In order for a bacterium to take up exogenous DNA from its surroundings, it must become competent. In S. pneumoniae, a number of complex events must occur to achieve a competent state, but it is believed that quorum sensing plays a role. [34] Competence stimulating peptide (CSP) is a 17-amino acid peptide autoinducer required for competency and subsequent genetic transformation. [35] CSP is produced by proteolytic cleavage of a 41-amino acid precursor peptide (ComC); is secreted by an ABC transporter (ComAB); and is detected by a sensor kinase protein (ComD) once it has reached a threshold concentration. [36] [37] [38] Detection is followed by autophosphorylation of ComD, which in turn, phosphorylates ComE. ComE is a response regulator responsible for activating transcription of comX, the product of which is required to activate transcription of a number of other genes involved in the development of competence. [39]

Bacillus subtilis: competence & sporulation

B. subtilis is a soil-dwelling microbe that uses quorum sensing to regulate two different biological processes: competence and sporulation. During stationary growth phase when B. subtilis are at high cell density, approximately 10% of the cells in a population are induced to become competent. It is believed that this subpopulation becomes competent to take up DNA that could potentially be used for the repair of damaged (mutated) chromosomes. [40] ComX (also known as competence factor) is a 10-amino acid peptide that is processed from a 55-amino acid peptide precursor. [41] Like most autoinducers, ComX is secreted and accumulates as a function of cell density. Once a threshold extracellular level is achieved, ComX is detected by a two-component ComP/ComA sensor kinase/response regulator pair. [42] Phosphorylation of ComA activates the expression of comS gene, ComS inhibits the degradation of ComK, and finally ComK activates the expression of a number of genes required for competence. [43]

Sporulation, on the other hand, is a physiological response of B. subtilis to depletion of nutrients within a particular environment. It is also regulated by extracellular signaling. When B. subtilis populations sense waning conditions, they respond by undergoing asymmetric cell division. [44] This ultimately produces spores that are adapted for dispersal and survival in unfavorable conditions. Sporulation in B. subtilis is mediated by CSF (sporulation factor), a pentapeptide cleaved from the precursor peptide PhrC. [45] CSF is secreted into the extracellular environment and is taken back up into cells via the ABC transporter Opp where it acts intracellularly. [46] While low internal concentrations of CSF contribute to competence, high concentrations induce sporulation. CSF inhibits a phosphatase, RabB, which increases the activity of Spo0A, favoring a switch in commitment from competence to the sporulation pathway [40]

Related Research Articles

<i>Arabidopsis</i> Genus of flowering plants

Arabidopsis (rockcress) is a genus in the family Brassicaceae. They are small flowering plants related to cabbage and mustard. This genus is of great interest since it contains thale cress, one of the model organisms used for studying plant biology and the first plant to have its entire genome sequenced. Changes in thale cress are easily observed, making it a very useful model.

In biology, quorum sensing or quorum signaling (QS) is the ability to detect and respond to cell population density by gene regulation. Quorum sensing is a type of cellular signaling, and more specifically can be considered a type of paracrine signaling. However, it also contains traits of both autocrine signaling: a cell produces both the autoinducer molecule and the receptor for the autoinducer. As one example, QS enables bacteria to restrict the expression of specific genes to the high cell densities at which the resulting phenotypes will be most beneficial, especially for phenotypes that would be ineffective at low cell densities and therefore too energetically costly to express. Many species of bacteria use quorum sensing to coordinate gene expression according to the density of their local population. In a similar fashion, some social insects use quorum sensing to determine where to nest. 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. As such, quorum sensing allows a commensal interaction between host and pathogenic bacteria. Quorum sensing may also be useful for cancer cell communications.

<i>Aliivibrio fischeri</i> Species of bacterium

Aliivibrio fischeri is a Gram-negative, rod-shaped bacterium found globally in marine environments. This species has bioluminescent properties, and is found predominantly in symbiosis with various marine animals, such as the Hawaiian bobtail squid. It is heterotrophic, oxidase-positive, and motile by means of a single polar flagella. Free-living A. fischeri cells survive on decaying organic matter. The bacterium is a key research organism for examination of microbial bioluminescence, quorum sensing, and bacterial-animal symbiosis. It is named after Bernhard Fischer, a German microbiologist.

<i>Vibrio harveyi</i> Species of bacterium

Vibrio harveyi is a Gram-negative, bioluminescent, marine bacterium in the genus Vibrio. V. harveyi is rod-shaped, motile, facultatively anaerobic, halophilic, and competent for both fermentative and respiratory metabolism. It does not grow below 4 °C. V. harveyi can be found free-swimming in tropical marine waters, commensally in the gut microflora of marine animals, and as both a primary and opportunistic pathogen of marine animals, including Gorgonian corals, oysters, prawns, lobsters, the common snook, barramundi, turbot, milkfish, and seahorses. It is responsible for luminous vibriosis, a disease that affects commercially farmed penaeid prawns. Additionally, based on samples taken by ocean-going ships, V. harveyi is thought to be the cause of the milky seas effect, in which, during the night, a uniform blue glow is emitted from the seawater. Some glows can cover nearly 6,000 sq mi (16,000 km2).

<i>N</i>-Acyl homoserine lactone Class of chemical compounds

N-Acyl homoserine lactones are a class of signaling molecules involved in bacterial quorum sensing, a means of communication between bacteria enabling behaviors based on population density.

<i>Pseudomonas aeruginosa</i> Species of bacterium

Pseudomonas aeruginosa is a common encapsulated, Gram-negative, aerobic–facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, P. aeruginosa is a multidrug resistant pathogen recognized for its ubiquity, its intrinsically advanced antibiotic resistance mechanisms, and its association with serious illnesses – hospital-acquired infections such as ventilator-associated pneumonia and various sepsis syndromes.

<span class="mw-page-title-main">Swarming motility</span>

Swarming motility is a rapid and coordinated translocation of a bacterial population across solid or semi-solid surfaces, and is an example of bacterial multicellularity and swarm behaviour. Swarming motility was first reported by Jorgen Henrichsen and has been mostly studied in genus Serratia, Salmonella, Aeromonas, Bacillus, Yersinia, Pseudomonas, Proteus, Vibrio and Escherichia.

<span class="mw-page-title-main">S-ribosylhomocysteine lyase</span>

The enzyme S-ribosylhomocysteine lyase catalyzes the reaction

<span class="mw-page-title-main">Lactonase</span>

Lactonase (EC 3.1.1.81, acyl-homoserine lactonase; systematic name N-acyl-L-homoserine-lactone lactonohydrolase) is a metalloenzyme, produced by certain species of bacteria, which targets and inactivates acylated homoserine lactones (AHLs). It catalyzes the reaction

<span class="mw-page-title-main">Autoinducer-2</span> Chemical compound

Autoinducer-2 (AI-2), a furanosyl borate diester or tetrahydroxy furan, is a member of a family of signaling molecules used in quorum sensing. AI-2 is one of only a few known biomolecules incorporating boron. First identified in the marine bacterium Vibrio harveyi, AI-2 is produced and recognized by many Gram-negative and Gram-positive bacteria. AI-2 arises by the reaction of 4,5-dihydroxy-2,3-pentanedione, which is produced enzymatically, with boric acid and is recognized by the two-component sensor kinase LuxPQ in Vibrionaceae.

<span class="mw-page-title-main">LuxR-type DNA-binding HTH domain</span>

In molecular biology, the LuxR-type DNA-binding HTH domain is a DNA-binding, helix-turn-helix (HTH) domain of about 65 amino acids. It is present in transcription regulators of the LuxR/FixJ family of response regulators. The domain is named after Vibrio fischeri luxR, a transcriptional activator for quorum-sensing control of luminescence. LuxR-type HTH domain proteins occur in a variety of organisms. The DNA-binding HTH domain is usually located in the C-terminal region of the protein; the N-terminal region often containing an autoinducer-binding domain or a response regulatory domain. Most luxR-type regulators act as transcription activators, but some can be repressors or have a dual role for different sites. LuxR-type HTH regulators control a wide variety of activities in various biological processes.

<span class="mw-page-title-main">Rhamnolipid</span> Chemical compound

Rhamnolipids are a class of glycolipid produced by Pseudomonas aeruginosa, amongst other organisms, frequently cited as bacterial surfactants. They have a glycosyl head group, in this case a rhamnose moiety, and a 3-(hydroxyalkanoyloxy)alkanoic acid (HAA) fatty acid tail, such as 3-hydroxydecanoic acid.

Interspecies quorum sensing is a type of quorum sensing in which bacteria send and receive signals to other species besides their own. This is accomplished by the secretion of signaling molecules which trigger a response in nearby bacteria at high enough concentrations. Once the molecule hits a certain concentration it triggers the transcription of certain genes such as virulence factors. It has been discovered that bacteria can not only interact via quorum sensing with members of their own species but that there is a kind of universal molecule that allows them to gather information about other species as well. This universal molecule is called autoinducer 2 or AI-2.

Acyl-homoserine-lactone synthase is an enzyme with systematic name acyl-(acyl-carrier protein):S-adenosyl-L-methionine acyltranserase . This enzyme catalyses the following chemical reaction

<span class="mw-page-title-main">Bioluminescent bacteria</span>

Bioluminescent bacteria are light-producing bacteria that are predominantly present in sea water, marine sediments, the surface of decomposing fish and in the gut of marine animals. While not as common, bacterial bioluminescence is also found in terrestrial and freshwater bacteria. These bacteria may be free living or in symbiosis with animals such as the Hawaiian Bobtail squid or terrestrial nematodes. The host organisms provide these bacteria a safe home and sufficient nutrition. In exchange, the hosts use the light produced by the bacteria for camouflage, prey and/or mate attraction. Bioluminescent bacteria have evolved symbiotic relationships with other organisms in which both participants benefit close to equally. Another possible reason bacteria use luminescence reaction is for quorum sensing, an ability to regulate gene expression in response to bacterial cell density.

Gelatinase biosynthesis-activating pheromone abbreviated as GBAP is a cyclic peptide produced by pathogenic bacteria such as Enterococcus faecalis. GAP is part of the quorum sensing system of certain bacteria where it positively regulates the expression of gelatinase and serine proteases that are under the control of the gelE-sprE operon.

Everett Peter Greenberg is an American microbiologist. He is the inaugural Eugene and Martha Nester Professor of Microbiology at the Department of Microbiology of the University of Washington School of Medicine. He is best known for his research on quorum sensing, and has received multiple awards for his work.

<span class="mw-page-title-main">Competence factor</span>

The ability of a cell to successfully incorporate exogenous DNA, or competency, is determined by competence factors. These factors consist of certain cell surface proteins and transcription factors that induce the uptake of DNA.

Diffusible signal factor (DSF) is found in several gram-negative bacteria and play a role in the formation of biofilms, motility, virulence, and antibiotic resistance. Xanthomonas campestris was the first bacteria known to have DSF. The synthesis of the DSF can be seen in rpfF and rpfB enzymes. An understanding of the DSF signaling mechanism could lead to further disease control.

References

  1. ↑ Davies, D.G., Parsek, M.R., Pearson, J.P., Iglewski, B.H., Costerton, J.W., Greenberg, E.P. (1998 April 10). The involvement of cell-to-cell signals in the development of a bacterial biofilm. Science. Retrieved from https://www.science.org/doi/abs/10.1126/science.280.5361.295.
  2. ↑ "Bacteria_communications".
  3. 1 2 3 4 5 6 7 Miller, M.B.; Bassler, B.L. (2001). "Quorum Sensing in Bacteria". Annu. Rev. Microbiol. 55: 165–199. doi:10.1146/annurev.micro.55.1.165. PMID   11544353.
  4. ↑ Nealson, K.; Platt, T.; Hastings, J.W. (1970). "Cellular Control of the Synthesis and Activity of the Bacterial Luminescent System". J. Bacteriol. 104 (1): 313–322. doi:10.1128/jb.104.1.313-322.1970. PMC   248216 . PMID   5473898.
  5. ↑ Nealson, K.H.; Hastings, J.W. (1979). "Bacterial bioluminescence: its control and ecological significance". Microbiol. Rev. 43 (4): 496–518. doi:10.1128/mmbr.43.4.496-518.1979. PMC   281490 . PMID   396467.
  6. ↑ Churchill, M.E.; Chen, L. (2011). "Structural basis of acyl-homoserine lactone-dependent signaling". Chem. Rev. 111 (1): 68–85. doi:10.1021/cr1000817. PMC   3494288 . PMID   21125993.
  7. ↑ Marketon, M.M.; Gronquist, M.R.; Eberhard, A.; González, J.E. (2002). "Characterization of the Sinorhizobium meliloti sinR/sinI locus and the production of novel N-acyl homoserine lactones". J. Bacteriol. 184 (20): 5686–5695. doi:10.1128/jb.184.20.5686-5695.2002. PMC   139616 . PMID   12270827.
  8. ↑ Pearson, J.P.; Van Deiden, C.; Iglewski, B.H. (1999). "Active efflux and diffusion are involved in transport of Pseudomonas aeruginosa cell-to-cell signals". J. Bacteriol. 181 (4): 1203–1210. doi:10.1128/JB.181.4.1203-1210.1999. PMC   93498 . PMID   9973347.
  9. ↑ Fuqua, C.; Winans, S.C. (1996). "Conserved cis-acting promoter elements are required for density-dependent transcription of Agrobacterium tumefaciens conjugal transfer genes". J. Bacteriol. 178 (2): 434–440. doi:10.1128/jb.178.2.435-440.1996. PMC   177675 . PMID   8550463.
  10. ↑ Freeman, J.A.; Lilley, B.N.; Bassler, B.L. (2000). "A genetic analysis of the functions of LuxN: a two-component hybrid sensor kinase that regulates quorum sensing in Vibrio harveyi". Mol. Microbiol. 35 (1): 139–149. doi: 10.1046/j.1365-2958.2000.01684.x . PMID   10632884.
  11. ↑ Dunny, G.M.; Leonard, B.A. (1997). "Cell-cell communication in gram-positive bacteria". Annu. Rev. Microbiol. 51: 527–564. doi:10.1146/annurev.micro.51.1.527. PMID   9343359.
  12. ↑ Harvastein, L.S.; Diep, D.B.; Nes, I.F. (1995). "A family of ABC transporters carry out proteolytic processing of their substrates concomitant with export". Mol. Microbiol. 16 (2): 229–240. doi:10.1111/j.1365-2958.1995.tb02295.x. PMID   7565085. S2CID   8086601.
  13. ↑ Cao, J.; Meighen, E.A. (1989). "Purification and structural identification of an autoinducer for the luminescence system of Vibrio harveyi". J. Biol. Chem. 264 (36): 21670–21676. doi: 10.1016/S0021-9258(20)88238-6 . PMID   2600086.
  14. ↑ Engebrecht, J.; Nealson, K.; Silverman, M. (1983). "Bacterial bioluminescence: isolation and genetic analysis of functions from Vibrio fischeri". Cell. 32 (3): 773–781. doi:10.1016/0092-8674(83)90063-6. PMID   6831560. S2CID   10882547.
  15. 1 2 3 Engebrecht, J.; Silverman, M. (1984). "Identification of genes and gene products necessary for bacterial bioluminescence". Proc. Natl. Acad. Sci. USA. 81 (13): 4154–4158. doi: 10.1073/pnas.81.13.4154 . PMC   345387 . PMID   6377310.
  16. ↑ McFall-Ngai, M.J.; Ruby, E. G. (1991). "Symbiont recognition and subsequent morphogenesis as early events in an animal– bacterial mutualism". Science. 254 (5037): 1491–1494. doi:10.1126/science.1962208. PMID   1962208.
  17. ↑ Young, R.E.; Roper, C.F. (1976). "Bioluminscent countershading in midwater animals: evidence from living squid". Science. 191 (4231): 1046–1048. doi:10.1126/science.1251214. PMID   1251214.
  18. 1 2 Eberhard, A.; Burlingame, A.L.; Eberhard, C.; Kenyon, G.L.; Nealson K.H.; Oppenheimer, N.J. (1981). "Structural identification of autoinducer of Photobacterium fischeri luciferase". Biochemistry. 20 (9): 2444–2449. doi:10.1021/bi00512a013. PMID   7236614.
  19. ↑ Kaplan, H.B.; Greenberg, E.P. (1985). "Diffusion of autoinducer is involved in regulation of the Vibrio fischeri luminescence system". J. Bacteriol. 163 (3): 1210–1214. doi:10.1128/jb.163.3.1210-1214.1985. PMC   219261 . PMID   3897188.
  20. ↑ Choi, S.H.; Greenberg, E.P. (1991). "The C-terminal region of the Vibrio fischeri LuxR protein contains an inducer-independent lux gene activating domain". Proc. Natl. Acad. Sci. USA. 88 (24): 11115–11119. doi: 10.1073/pnas.88.24.11115 . PMC   53084 . PMID   1763027.
  21. ↑ Singh, P.K.; Schaefer, A.L.; Parsek, M.R.; Moninger, T.O.; Welsh, M.J.; Greenberg E.P. (2000). "Quorum-sensing signals indicate that cystic fibrosis lungs are infected with bacterial biofilms". Nature. 407 (6805): 762–764. doi:10.1038/35037627. PMID   11048725. S2CID   4372096.
  22. 1 2 Passador, L.; Cook, J.M.; Gambello, M.J.; Rust, L.; Iglewski, B.H (1993). "Expression of Pseudomonas aeruginosa virulence genes requires cell-cell communication". Science. 260 (5111): 1127–1130. doi:10.1126/science.8493556. PMID   8493556.
  23. 1 2 Brint, J.M.; Ohman, D.E. (1995). "Synthesis of multiple exoproducts in Pseudomonas aeruginosa is under the control of RhlR-RhlI, another set of regulators in strain PAO1 with homology to the autoinducer responsive LuxR-LuxI family". J. Bacteriol. 177 (24): 7155–7163. doi:10.1128/jb.177.24.7155-7163.1995. PMC   177595 . PMID   8522523.
  24. ↑ Pearson, J.P.; Gray, K.M.; Passador, L.; Tucker, K.D.; Eberhard, A.; et al. (1994). "Structure of the autoinducer required for expression of Pseudomonas aeruginosa virulence genes". Proc. Natl. Acad. Sci. USA. 91 (1): 197–201. doi: 10.1073/pnas.91.1.197 . PMC   42913 . PMID   8278364.
  25. ↑ Pearson, J.P.; Passador, L.; Iglewski, B.H.; Greenberg, E.P. (1995). "A second N-acylhomoserine lactone signal produced by Pseudomonas aeruginosa". Proc. Natl. Acad. Sci. USA. 92 (5): 1490–1494. doi: 10.1073/pnas.92.5.1490 . PMC   42545 . PMID   7878006.
  26. ↑ Ochsner, U.A.; Reiser, J. (1995). "Autoinducer-mediated regulation of rhamnolipid biosurfactant synthesis in Pseudomonas aeruginosa". Proc. Natl. Acad. Sci. USA. 92 (14): 6424–6428. doi: 10.1073/pnas.92.14.6424 . PMC   41530 . PMID   7604006.
  27. ↑ Pesci, E.C.; Pearson, J.P.; Seed, P.C.; Iglewski, B.H. (1997). "Regulation of las and rhl quorum sensing in Pseudomonas aeruginosa". J. Bacteriol. 179 (10): 3127–3132. doi:10.1128/jb.179.10.3127-3132.1997. PMC   179088 . PMID   9150205.
  28. ↑ Pesci, E.C.; Milbank, J.B.; Pearson, J.P.; McKnight, S.; Kende, A.S.; et al. (1999). "). Quinolone signaling in the cell-to-cell communication system of Pseudomonas aeruginosa" (PDF). Proc. Natl. Acad. Sci. USA. 96 (20): 11229–11234. doi: 10.1073/pnas.96.20.11229 . PMC   18016 . PMID   10500159.
  29. ↑ Piper, K.R.; Beck von Bodman, S.; Farrand, S.K. (1993). "Conjugation factor of Agrobacterium tumefaciens regulates Ti plasmid transfer by autoinduction". Nature. 362 (6419): 448–450. doi:10.1038/362448a0. PMID   8464476. S2CID   4373143.
  30. ↑ Zhang, L.; Murphy, P.J.; Kerr, A.; Tate, M.E. (1993). "Agrobacterium conjugation and gene regulation by N-acyl-L-homoserine lactones". Nature. 362 (6419): 445–448. doi:10.1038/362446a0. PMID   8464475. S2CID   4370414.
  31. ↑ Hinton, J.C.; Sidebotham, J.M.; Hyman, L.J.; Perombelon, M.C.; Salmond, G.P. (1989). "). Isolation and characterisation of transposon-induced mutants of Erwinia carotovora subsp. atroseptica exhibiting reduced virulence". Mol. Gen. Genet. 217 (1): 141–148. doi:10.1007/bf00330953. PMID   2549365. S2CID   27047539.
  32. ↑ Bainton, N.J.; Stead, P.; Chhabra, S.R.; Bycroft, B.W.; Salmond, G.P.; et al. (1992). "N-(3-oxohexanoyl)-L-homoserine lactone regulates carbapenem antibiotic production in Erwinia carotovora". Biochem. J. 288 (3): 997–1004. doi:10.1042/bj2880997. PMC   1131986 . PMID   1335238.
  33. ↑ Dawson, M.; Sia, R. (1931). "In vitro transformation of pneumococcal types I. A technique for inducing transformation of pneumococcal types in vitro". J. Exp. Med. 54 (5): 681–699. doi:10.1084/jem.54.5.681. PMC   2132061 . PMID   19869950.
  34. ↑ Havarstein, L.S.; Morrison, D.A. (1999). "Quorum sensing and peptide pheromones in Streptococcal competence for genetic transformation". Cell-Cell Signaling in Bacteria. (Washington, DC: ASM Press): 9–26.
  35. ↑ Havarstein, L.S.; Coomaraswamy, G.; Morrison, D.A. (1995). "An unmodified heptadecapeptide pheromone induces competence for genetic transformation in Streptococcus pneumoniae". Proc. Natl. Acad. Sci. USA. 92 (24): 11140–11144. doi: 10.1073/pnas.92.24.11140 . PMC   40587 . PMID   7479953.
  36. ↑ Pozzi, G.; Masala, L.; Iannelli, F.; Manganelli, R.; Havarstein, L.S.; et al. (1996). "Competence for genetic transformation in encapsulated strains of Streptococcus pneumoniae: two allelic variants of the peptide pheromone". J. Bacteriol. 178 (20): 6087–6090. doi:10.1128/jb.178.20.6087-6090.1996. PMC   178474 . PMID   8830714.
  37. ↑ Hui, F.M.; Morrison, D.A. (1991). "Genetic transformation in Streptococcus pneumoniae: nucleotide sequence analysis shows comA, a gene required for competence induction, to be a member of the bacterial ATP-dependent transport protein family". J. Bacteriol. 173 (1): 372–381. doi:10.1128/jb.173.1.372-381.1991. PMC   207196 . PMID   1987129.
  38. ↑ Pestova, E.V.; Havarstein, L.S.; Morrison, D.A. (1996). "Regulation of competence for genetic transformation in Streptococcus pneumoniae by an auto-induced peptide pheromone and a two-component regulatory system". Mol. Microbiol. 21 (4): 853–862. doi:10.1046/j.1365-2958.1996.501417.x. PMID   8878046. S2CID   487722.
  39. ↑ Lee, M.S.; Morrison, D.A. (1999). "Identification of a new regulator of Streptococcus pneumoniae linking quorum sensing to competence for genetic transformation". J. Bacteriol. 181 (16): 5004–5016. doi:10.1128/JB.181.16.5004-5016.1999. PMC   93990 . PMID   10438773.
  40. 1 2 Grossman, A.D. (1995). "Genetic networks controlling the initiation of sporulation and the development of genetic competence in Bacillis subtilis". Annu. Rev. Genet. 29: 477–508. doi:10.1146/annurev.ge.29.120195.002401. PMID   8825484.
  41. ↑ Magnuson, R.; Solomon, J.; Grossman, A.D. (1994). "Biochemical and genetic characterization of a competence pheromone from B. subtilis". Cell. 77 (2): 207–216. doi:10.1016/0092-8674(94)90313-1. PMID   8168130. S2CID   20800369.
  42. ↑ Solomon, J.M.; Magnuson, R.; Srivastava, A.; Grossman, A.D. (1995). "Convergent sensing pathways mediate response to two extracellular competence factors in Bacillus subtilis". Genes Dev. 9 (5): 547–558. doi: 10.1101/gad.9.5.547 . PMID   7698645.
  43. ↑ Turgay, K.; Hahn, J.; Burghoorn, J.; Dubnau, D. (1998). "Competence in Bacillus subtilis is controlled by regulated proteolysis of a transcription factor". EMBO J. 17 (22): 6730–6738. doi:10.1093/emboj/17.22.6730. PMC   1171018 . PMID   9890793.
  44. ↑ Hoch, J.A. (1995). "Control of cellular development in sporulating bacteria by the phosphorelay two-component signal transduction system.". Two Component Signal Transduction. Washington, DC.: ASM Press. pp. 129–144. doi:10.1128/9781555818319.ch8. ISBN   9781555818319.
  45. ↑ Solomon, J.M.; Lazazzera, B.A.; Grossman, A.D. (1996). "Purification and characterization of an extracellular peptide factor that affects two different developmental pathways in Bacillus subtilis". Genes Dev. 10 (16): 2014–2024. doi: 10.1101/gad.10.16.2014 . PMID   8769645.
  46. ↑ Lazazzera, B.A.; Solomon, J.M.; Grossman, A.D. (1997). "An exported peptide functions intracellularly to contribute to cell density signaling in B. subtilis". Cell. 89 (6): 917–925. doi:10.1016/S0092-8674(00)80277-9. hdl: 1721.1/83874 . PMID   9200610. S2CID   14321882.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.