Functional characterization of exopolyphosphatase/guanosine pentaphosphate phosphohydrolase (PPX/GPPA) of<i>Campylobacter jejuni</i>

Malde, Anandkumar; Gangaiah, Dharanesh; Chandrashekhar, Kshipra; Pina-Mimbela, Ruby; Torrelles, Jordi B.; Rajashekara, Gireesh

doi:10.4161/viru.28311

Cited by 32 publications

(36 citation statements)

References 57 publications

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“…Thus, poly(P) accumulation in Campylobacter jejuni (61) and P. aeruginosa (62) was associated with defective biofilm formation. Furthermore, deficiency of a polyphosphate kinase responsible for poly(P) synthesis in P. aeruginosa also resulted in defective biofilms (63).…”

Section: Discussionmentioning

confidence: 99%

Stringent Response Factors PPX1 and PPK2 Play an Important Role in Mycobacterium tuberculosis Metabolism, Biofilm Formation, and Sensitivity to Isoniazid In Vivo

Chuang

Dutta

Hung

et al. 2016

Antimicrob Agents Chemother

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g Mycobacterium tuberculosis remains a global health threat largely due to the lengthy duration of curative antibiotic treatment, contributing to medical nonadherence and the emergence of drug resistance. This prolonged therapy is likely due to the presence of M. tuberculosis persisters, which exhibit antibiotic tolerance. Inorganic polyphosphate [poly(P)] is a key regulatory molecule in the M. tuberculosis stringent response mediating antibiotic tolerance. The polyphosphate kinase PPK1 is responsible for poly(P) synthesis in M. tuberculosis, while the exopolyphosphatases PPX1 and PPX2 and the GTP synthase PPK2 are responsible for poly(P) hydrolysis. In the present study, we show by liquid chromatography-tandem mass spectrometry that poly(P)-accumulating M. tuberculosis mutant strains deficient in ppx1 or ppk2 had significantly lower intracellular levels of glycerol-3-phosphate (G3P) and 1-deoxy-xylulose-5-phosphate. Real-time PCR revealed decreased expression of genes in the G3P synthesis pathway in each mutant. The ppx1-deficient mutant also showed a significant accumulation of metabolites in the tricarboxylic acid cycle, as well as altered arginine and NADH metabolism. Each poly(P)-accumulating strain showed defective biofilm formation, while deficiency of ppk2 was associated with increased sensitivity to plumbagin and meropenem and deficiency of ppx1 led to enhanced susceptibility to clofazimine. A DNA vaccine expressing ppx1 and ppk2, together with two other members of the M. tuberculosis stringent response, M. tuberculosis rel and sigE, did not show protective activity against aerosol challenge with M. tuberculosis, but vaccine-induced immunity enhanced the killing activity of isoniazid in a murine model of chronic tuberculosis. In summary, poly(P)-regulating factors of the M. tuberculosis stringent response play an important role in M. tuberculosis metabolism, biofilm formation, and antibiotic sensitivity in vivo.

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Section: Discussionmentioning

confidence: 99%

Stringent Response Factors PPX1 and PPK2 Play an Important Role in Mycobacterium tuberculosis Metabolism, Biofilm Formation, and Sensitivity to Isoniazid In Vivo

Chuang

Dutta

Hung

et al. 2016

Antimicrob Agents Chemother

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“…In some microbes Ppk2 can produce poly-P from GTP (17), but this activity has not been reported in C. jejuni . C. jejuni also encodes two exo-polyphosphatases, Ppx1 and Ppx2, which degrade poly-P into inorganic phosphate and have guanosine pentaphosphate hydrolase activity to generate guanosine tetraphosphate (ppGpp) (18). With the regulatory gene product SpoT, ppGpp regulates the stringent response of C.jejuni , contributing to survival in stationary phase (19).…”

Section: Resultsmentioning

confidence: 99%

Phosphate transporter PstSCAB of Campylobacter jejuni is essential for lactate-dependent growth and colonization in chickens

Sinha

et al. 2019

Preprint

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45Campylobacter jejuni causes acute gastroenteritis world-wide and is transmitted primarily 46 through poultry, in which it is often a commensal member of the intestinal microbiota. Previous 47RNASeq experiments showed that transcripts from an operon encoding a high affinity phosphate 48 transporter (PstSCAB) of C. jejuni were among the most abundant when grown in chickens. 49Elevated levels of the pstSCAB mRNA were also identified in an RNASeq experiment from 50 human infection studies. In this study, we explore the role of PstSCAB in the biology and 51 colonization potential of C. jejuni. Our experimental results demonstrate that cells lacking 52PstSCAB survive poorly in stationary phase, nutrient-limiting media, and under osmotic 53 conditions reflective of those in the chicken. Polyphosphate levels in the mutant cells were 54 elevated at stationary phase, consistent with alterations in expression of polyphosphate 55 metabolism genes. C. jejuni were highly attenuated in colonization of newly hatched chicks, 56 recovered at levels several orders of magnitude below wild type. Mutant and wild type grew 57 similarly in complex media but the pstSCAB mutant exhibited a significant growth defect in 58 minimal media supplemented with L-lactate, postulated as a carbon source in vivo. Poor growth 59 in lactate correlated with diminished expression of acetogenesis pathway genes previously 60 demonstrated as important for colonizing chickens. The phosphate transport system is thus 61 essential for diverse aspects of C. jejuni physiology and in vivo fitness and survival.

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“…Another difference between ppk mutants and ppx mutants can be found in motility. A ppk1 mutation did not change motility, 3 whereas ppx mutations significantly reduced the motility of C. jejuni 7 . In addition, the spoT mutation substantially impairs C. jejuni resistance to rifampicin, 6 and a ppk2 mutant exhibits increased susceptibility to antibiotics, such as erythromycin and tetracycline 4 .…”

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confidence: 97%

“…In addition to PPKs, the exopolyphosphatases/guanosine pentaphosphate (pppGpp) phosphohydrolase (PPX/GPPA) also control the levels of poly-P and (p)ppGpp 1 . Malde et al identified and characterized two PPX/GPPAs (PPX1 and PPX2) in C. jejuni , demonstrating that PPXs affect the levels of poly-P and ppGpp and contribute to the virulence of C. jejuni 7 . Mutations of ppx1 and ppx2 influenced various virulence-related phenotypes of C. jejuni , such as biofilms, motility, and invasion and intracellular survival 7 .…”

mentioning

confidence: 99%

“…In addition, the spoT mutation substantially impairs C. jejuni resistance to rifampicin, 6 and a ppk2 mutant exhibits increased susceptibility to antibiotics, such as erythromycin and tetracycline 4 . However, ppx mutations did not change the resistance to rifampicin, and the authors speculated that ppGpp levels in the ppx mutants would not be significant enough to affect rifampicin sensitivity 7 . Overall, comparison of the phonotype changes between ppx mutants and ppk mutants and the spoT mutant suggests that PPXs would be a complementary mechanism related to poly-P and stringent response.…”

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confidence: 99%

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A tangle of poly-phosphate inCampylobacter

Jeon

2014

Virulence

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Functional characterization of exopolyphosphatase/guanosine pentaphosphate phosphohydrolase (PPX/GPPA) ofCampylobacter jejuni

Cited by 32 publications

References 57 publications

Stringent Response Factors PPX1 and PPK2 Play an Important Role in Mycobacterium tuberculosis Metabolism, Biofilm Formation, and Sensitivity to Isoniazid In Vivo

Stringent Response Factors PPX1 and PPK2 Play an Important Role in Mycobacterium tuberculosis Metabolism, Biofilm Formation, and Sensitivity to Isoniazid In Vivo

Phosphate transporter PstSCAB of Campylobacter jejuni is essential for lactate-dependent growth and colonization in chickens

A tangle of poly-phosphate inCampylobacter

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