31:
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has a protein to protect other periplasmic proteins from low pH environments called the Asr protein. The gene responsible for this protein is PhoB-dependent, and can only be turned on when the Pho regulon is activated by low Pi concentration. Synthesis of the Asr protein imparts acid shock resistance
234:
Because bacteria use the Pho regulon to maintain homeostasis of Pi, it has the added effect of being used to control other genes. Many of the other genes activated or repressed by the Pho regulon cause virulence in bacterial pathogens. Three ways that this regulon effects virulence and pathogenicity
314:
enabling it to survive in environments like the stomach which has a low pH. Many acid tolerance genes are induced by more than just the low pH environment and require other environmental signals to be present in order to be activated. These specific nutrients being present or in low concentrations,
288:
are a mixture of microorganisms, layered together and usually adhered to a surface. The advantages of a biofilm include resistance to environmental stresses, antibiotics, and the ability to more easily obtain nutrients. PhoB is used to enhance biofilm formation in environments where Pi is not in
144:
seven total proteins are used to detect intracellular levels of inorganic phosphate along with transfusing that signal appropriately. Of the seven proteins, one is a metal binding protein (PhoU) and four are phosphate-specific transporters (Pst S, Pst C, Pst A, and Pst B). The transcriptional
221:
binds its transcription regulator, PhoP and the histidine kinase, PhoR to the Pho-regulon gene which induces a production of teichuronic acid. Furthermore, recent studies have suggested the critical role that techoic acid plays in the cell wall of
112:. This occurs when the cell senses low concentrations of phosphate within its internal environment causing the response regulator to be phosphorylated inducing an overall decrease in gene transcription. This mechanism is ubiquitous within
157:
which can use both inorganic and organic phosphate, as well as naturally occurring or synthetic phosphates (Phn). Several enzymes breakdown the compounds of the alternative phosphates, allowing the organism to use the phosphate via the
276:
promoter and stopping the ToxR regulon from being activated. Evidence supporting Pi as the signal is given by how the regulon is not repressed under high Pi conditions. The regulatory cascade is only repressed under low Pi conditions.
271:
is activated when Pi is low to prevent the production of toxins. It could be activated by other signals in the environment, but it has been shown that PhoB directly inhibits the toxins production by binding to the
297:
This is not always the effect of the Pho regulon as for other species in different environments it is more advantageous to not be in biofilm when Pi is low. In these cases PhoB represses biofilm formation.
83:
within the cell. Under low nutrient availability, the Pho regulon helps the cell survive and thrive despite a depletion of phosphate within the environment. When this occurs, phosphate starvation-inducible
74:
that are capable of phosphate assimilation in addition to extracting inorganic phosphate from organic sources. This is an essential process since phosphate plays an important role in cellular membranes,
600:
Liu, Wei; Hulett, F. Marion (1998). "Comparison of PhoP binding to the tuaA promoter with PhoP binding to other Pho-regulon promoters establishes a
Bacillus subtilis Pho core binding site".
153:
Although inorganic phosphate is primarily used in the Pho regulon system, there are several species of bacteria that can utilize varying forms of phosphate. One example is seen in
66:
as an operating system for the bacterial strain, and was later identified in other species. The Pho system is composed of various components including extracellular
108:(PhoB/PhoR) on the cytoplasmic side of the membrane. These proteins bind to upstream promoters in the pho regulon in order to induce a general change in
250:, a toxin released to kill both microbes and mammalian cells alike. The pyocyanin production occurs when activated by PhoB. This implies that
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217:
also shares some similarities when encountering low intracellular phosphate concentrations. Under phosphate-starved conditions
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uses the low Pi as a signal that the host has been damaged and to start producing toxin to improve chances of its survival.
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by acting as a phosphate reservoir and storing the necessary amount of inorganic phosphate in phosphate-starved conditions.
170:
17:
97:
667:"Teichoic Acid Is an Essential Polymer in Bacillus subtilis That Is Functionally Distinct from Teichuronic Acid"
854:
849:
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Depletion of inorganic phosphate within the cell is required for activation of the Pho regulon in most
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response regulator PhoR activates PhoB when it senses low intracellular inorganic phosphate levels.
194:
109:
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can use either one of the pathways to cleave the C-P bond found in the alternative phosphates.
176:
164:
789:"The Acid-Inducible asr Gene in Escherichia coli: Transcriptional Control by the phoBR Operon"
787:
Sužiedėlienė, Edita; Sužiedėlis, Kęstutis; Garbenčiūtė, Vaida; Normark, Staffan (April 1999).
645:
535:
Monds, Russell D.; Newell, Peter D.; Schwartzman, Julia A.; O'Toole, George A. (2006-03-01).
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209:, the transcriptional response regulator (PhoB/PhoR) retain the same function they play in
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is a known opportunistic pathogen. One of its virulence factors is its ability to produce
8:
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Bhavsar, Amit P.; Erdman, Laura K.; Schertzer, Jeffrey W.; Brown, Eric D. (2004-12-01).
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729:"PhoB regulates both environmental and virulence gene expression in Vibrio cholerae"
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88:) genes activate other proteins that aid in the transport of inorganic phosphate.
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use a different pathway called the phosphonatase pathway, whereas the bacterium
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is a regulatory mechanism used for the conservation and management of inorganic
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494:
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Vershinina, O. A.; Znamenskaya, L. V. (2002). "The Pho
Regulons of Bacteria".
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sufficient supply. This has been shown in multiple microbes including
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sensor protein (PhoR) within the inner membrane and a transcriptional
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Pratt, Jason T.; Ismail, Ayman M.; Camilli, Andrew (September 2010).
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53:
537:"Conservation of the Pho regulon in Pseudomonas fluorescens Pf0-1"
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has its toxin genes repressed by PhoB. It is thought that PhoB in
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are toxin production, biofilm formation, and acid tolerance.
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Regulation of inorganic phosphate within the cellular system.
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Although the Pho regulon system is most widely studied in
415:"The Pho regulon: a huge regulatory network in bacteria"
183:
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192:it is found in other bacterial species such as
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335:Wanner, B. L.; Chang, B. D. (December 1987).
337:"The phoBR operon in Escherichia coli K-12"
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140:. In the most commonly studied bacterium,
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230:The Pho regulon's effect on pathogenesis
162:pathway. Other species of bacteria like
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27:Phosphate regulatory mechanism in cells
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541:Applied and Environmental Microbiology
413:Santos-Beneit, Fernando (2015-04-30).
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650:: CS1 maint: unflagged free DOI (
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745:10.1111/j.1365-2958.2010.07310.x
683:10.1128/JB.186.23.7865-7873.2004
353:10.1128/jb.169.12.5569-5574.1987
805:10.1128/JB.181.7.2084-2093.1999
561:10.1128/AEM.72.3.1910-1924.2006
98:two-component regulatory system
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60:. It was first discovered in
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614:10.1099/00221287-144-5-1443
149:Alternative phosphate usage
132:Signal transduction pathway
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116:-positive, gram-negative,
419:Frontiers in Microbiology
432:10.3389/fmicb.2015.00402
291:Pseudomonas, V. cholera,
793:Journal of Bacteriology
671:Journal of Bacteriology
495:10.1023/a:1020547616096
341:Journal of Bacteriology
207:Pseudomonas fluorescens
195:Pseudomonas fluorescens
733:Molecular Microbiology
244:Pseudomonas aeruginosa
177:Enterobacter aerogenes
171:Salmonella typhimurium
165:Pseudomonas aeruginosa
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553:2006ApEnM..72.1910M
855:Bacterial genetics
110:gene transcription
106:response regulator
77:genetic expression
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850:Molecular biology
677:(23): 7865–7873.
347:(12): 5569–5574.
281:Biofilm formation
215:Bacillus subtilis
201:Bacillus subtilis
18:Phosphate regulon
16:(Redirected from
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269:V. cholerae
219:B. subtilis
138:prokaryotes
56:within the
844:Categories
323:References
81:metabolism
813:0021-9193
753:0950-382X
691:0021-9193
622:1350-0872
569:0099-2240
503:0026-2617
441:1664-302X
361:0021-9193
248:pyocyanin
160:C-P lyase
54:phosphate
40:Phosphate
831:10094685
771:20659293
709:15547257
587:16517638
519:36152299
511:12449623
459:25983732
295:E. coli.
286:Biofilms
142:E. coli,
92:Function
762:2981138
638:7062262
630:9611818
578:1393216
549:Bibcode
450:4415409
425:: 402.
379:2824439
312:E. coli
307:E. coli
211:E. coli
155:E. coli
126:archaea
68:enzymes
49:regulon
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122:yeasts
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634:S2CID
515:S2CID
274:tcpPH
827:PMID
809:ISSN
767:PMID
749:ISSN
705:PMID
687:ISSN
652:link
626:PMID
618:ISSN
583:PMID
565:ISSN
507:PMID
499:ISSN
455:PMID
437:ISSN
375:PMID
357:ISSN
293:and
198:and
168:and
114:gram
70:and
58:cell
38:The
817:PMC
801:doi
797:181
757:PMC
741:doi
695:PMC
679:doi
675:186
610:doi
606:144
573:PMC
557:doi
491:doi
445:PMC
427:doi
365:PMC
349:doi
345:169
310:to
205:In
86:psi
44:Pho
846::
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