Two Residues Predominantly Dictate Functional Difference in Motility between Shewanella oneidensis Flagellins FlaA and FlaB

Sun, Linlin; Dong, Yangyang; Shi, Miaomiao; Jin, Miao; Zhou, Qing; Luo, Zhao‐Qing; Gao, Haichun

doi:10.1074/jbc.m114.552000

Cited by 21 publications

(39 citation statements)

References 52 publications

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“…In addition, expression of the nagZ and ampG genes in trans conferred on the corresponding mutants the lowest levels of BlaA activity under all tested conditions. This can be readily explained by overexpression, an intrinsic feature of the multiple-copy vector pHG101 (31,33,34). Based on these results, we conclude that NagZ and AmpG exert a repressive effect on the blaA gene, leading to the elevated resistance to ampicillin at all levels.…”

Section: Resultsmentioning

confidence: 83%

Distinct Roles of Major Peptidoglycan Recycling Enzymes in β-Lactamase Production in Shewanella oneidensis

Yin

Mao

et al. 2014

Antimicrob Agents Chemother

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c ␤-Lactam antibiotics were the earliest discovered and are the most widely used group of antibiotics that work by inactivating penicillin-binding proteins to inhibit peptidoglycan biosynthesis. As one of the most efficient defense strategies, many bacteria produce ␤-lactam-degrading enzymes, ␤-lactamases, whose biochemical functions and regulation have been extensively studied. A signal transduction pathway for ␤-lactamase induction by ␤-lactam antibiotics, consisting of the major peptidoglycan recycling enzymes and the LysR-type transcriptional regulator, AmpR, has been recently unveiled in some bacteria. Because inactivation of some of these proteins, especially the permease AmpG and the ␤-hexosaminidase NagZ, results in substantially elevated susceptibility to the antibiotics, these have been recognized as potential therapeutic targets. Here, we show a contrasting scenario in Shewanella oneidensis, in which the homologue of AmpR is absent. Loss of AmpG or NagZ enhances ␤-lactam resistance drastically, whereas other identified major peptidoglycan recycling enzymes are dispensable. Moreover, our data indicate that there exists a parallel signal transduction pathway for ␤-lactamase induction, which is independent of either AmpG or NagZ.

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Section: Resultsmentioning

confidence: 83%

Distinct Roles of Major Peptidoglycan Recycling Enzymes in β-Lactamase Production in Shewanella oneidensis

Yin

Mao

et al. 2014

Antimicrob Agents Chemother

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“…; Sun et al. ). Although the expression of the scyA gene within pHG101 was sufficient to significantly elevate the nitrite resistance of the ∆ cyd strain, it failed to elicit any noticeable augment in the nitrite resistance in the wild type (Fig.…”

Section: Resultsmentioning

confidence: 98%

Regulation of nitrite resistance of the cytochrome cbb₃ oxidase by cytochrome c ScyA in Shewanella oneidensis

et al. 2014

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Cytochrome c proteins, as enzymes to exchange electrons with substrates or as pure electron carriers to shuttle electrons, play vital roles in bacterial respiration and photosynthesis. In Shewanella oneidensis, a research model for the respiratory diversity, at least 42 c-type cytochromes are predicted to be encoded in the genome and are regarded to be the foundation of its highly branched electron transport pathways. However, only a small number of c-type cytochromes have been extensively studied. In this study, we identify soluble cytochrome c ScyA as an important factor influencing the nitrite resistance of a strain devoid of the bd oxidase by utilizing a newly developed transposon mutagenesis vector, which enables overexpression of the gene(s) downstream of the insertion site. We show that when in overabundance ScyA facilitates growth against nitrite inhibition by enhancing nitrite resistance of the cbb3 oxidase. Based on the data presented in this study, we suggest two possible mechanisms underlying the observed effect of ScyA: (1) ScyA increases electron flow to the cbb3 oxidase; (2) ScyA promotes nitrite resistance of the cbb3 oxidase, possibly by direct interaction.

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“…To investigate whether nitrite inhibition of growth on fumarate, at least in part, is due to NapB in overabundance, we assessed effect of NapB in varying amounts on respiration of fumarate in the absence of nitrite. The napB gene was expressed in the wild-type strain under the control of IPTG-inducible promoter P tac , which is slightly leaky4950. Overexpression of the napB gene led to severe growth defect on fumarate (Fig.…”

Section: Resultsmentioning

confidence: 99%

NapB in excess inhibits growth of Shewanella oneidensis by dissipating electrons of the quinol pool

Jin

Zhang

Sun

et al. 2016

Sci Rep

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Shewanella, a group of ubiquitous bacteria renowned for respiratory versatility, thrive in environments where various electron acceptors (EAs) of different chemical and physiological characteristics coexist. Despite being extensively studied, we still know surprisingly little about strategies by which multiple EAs and their interaction define ecophysiology of these bacteria. Previously, we showed that nitrite inhibits growth of the genus representative Shewanella oneidensis on fumarate and presumably some other CymA (quinol dehydrogenase)-dependent EAs by reducing cAMP production, which in turn leads to lowered expression of nitrite and fumarate reductases. In this study, we demonstrated that inhibition of fumarate growth by nitrite is also attributable to overproduction of NapB, the cytochrome c subunit of nitrate reductase. Further investigations revealed that excessive NapB per se inhibits growth on all EAs tested, including oxygen. When overproduced, NapB acts as an electron shuttle to dissipate electrons of the quinol pool, likely to extracellullar EAs, because the Mtr system, the major electron transport pathway for extracellular electron transport, is implicated. The study not only sheds light on mechanisms by which certain EAs, especially toxic ones, impact the bacterial ecophysiology, but also provides new insights into how electron shuttle c-type cytochromes regulate multi-branched respiratory networks.

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Two Residues Predominantly Dictate Functional Difference in Motility between Shewanella oneidensis Flagellins FlaA and FlaB

Cited by 21 publications

References 52 publications

Distinct Roles of Major Peptidoglycan Recycling Enzymes in β-Lactamase Production in Shewanella oneidensis

Distinct Roles of Major Peptidoglycan Recycling Enzymes in β-Lactamase Production in Shewanella oneidensis

Regulation of nitrite resistance of the cytochrome cbb₃ oxidase by cytochrome c ScyA in Shewanella oneidensis

NapB in excess inhibits growth of Shewanella oneidensis by dissipating electrons of the quinol pool

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Two Residues Predominantly Dictate Functional Difference in Motility between Shewanella oneidensis Flagellins FlaA and FlaB

Cited by 21 publications

References 52 publications

Distinct Roles of Major Peptidoglycan Recycling Enzymes in β-Lactamase Production in Shewanella oneidensis

Distinct Roles of Major Peptidoglycan Recycling Enzymes in β-Lactamase Production in Shewanella oneidensis

Regulation of nitrite resistance of the cytochrome cbb3 oxidase by cytochrome c ScyA in Shewanella oneidensis

NapB in excess inhibits growth of Shewanella oneidensis by dissipating electrons of the quinol pool

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Regulation of nitrite resistance of the cytochrome cbb₃ oxidase by cytochrome c ScyA in Shewanella oneidensis