DifA, a Methyl-Accepting Chemoreceptor Protein-Like Sensory Protein, Uses a Novel Signaling Mechanism to Regulate Exopolysaccharide Production in<i>Myxococcus xanthus</i>

Xu, Qian; Black, Wesley P.; Nascimi, Heidi M.; Yang, Zhaomin

doi:10.1128/jb.00944-10

Cited by 9 publications

(4 citation statements)

References 47 publications

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“…After pK treatment, 60% of initial exoproteins were digested, whereas DNAse was able to remove 25% of the initial exoproteins mainly through their reduction. In contrast, significant removal of exopolysaccharides was not observed (Figure 5B), in agreement with previous studies (Xu et al, 2011; Lawrence et al, 2016). pK and DNAse treatments remarkably decreased current density compared with that of normal MR-1 cells (Figure 5A, purple and green lines).…”

Section: Resultssupporting

confidence: 93%

Mediation of Extracellular Polymeric Substances in Microbial Reduction of Hematite by Shewanella oneidensis MR-1

Gao

Liu

et al. 2019

Front. Microbiol.

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Extracellular electron transfer (EET) plays a fundamental role in microbial reduction/oxidation of minerals. Extracellular polymeric substances (EPS) surrounding the cells constitute a matrix that separates the cell’s outer membrane from insoluble minerals and environmental fluid. This study investigated the effects of EPS on EET processes during microbial reduction of hematite by the iron-reducing strain Shewanella oneidensis MR-1 (MR-1). Electrochemical characterization techniques were employed to determine the influence of EPS components on the redox ability of MR-1. Cells with removed EPS exhibited approximately 30% higher hematite reduction than regular MR-1 cells, and produced a current density of 56 μA cm -2 , corresponding to 3–4 fold that of regular MR-1. The superior EET of EPS-deprived cells could be attributed to direct contact between outer membrane proteins and hematite surface, as indicated by more redox peaks being detected by cyclic voltammetry and differential pulse voltammetry. The significantly reduced current density of MR-1 cells treated with proteinase K and deoxyribonuclease suggests that the electron transfer capacity across the EPS layer depends mainly on the spatial distribution of specific proteins and electron shuttles. Exopolysaccharides in EPS tend to inhibit electron transfer, however they also favor the attachment of cells onto hematite surfaces. Consistently, the charge transfer resistance of cells lacking EPS was only 116.3 Ω, approximately 44 times lower than that of regular cells (5,139.1 Ω). These findings point to a negative influence of EPS on EET processes for microbial reduction/oxidation of minerals.

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Section: Resultssupporting

confidence: 93%

Mediation of Extracellular Polymeric Substances in Microbial Reduction of Hematite by Shewanella oneidensis MR-1

Gao

Liu

et al. 2019

Front. Microbiol.

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“…epsH encodes a glycosyltransferase essential for exopolysaccharide production [39]. difA is a methyl-accepting chemotaxis protein (MCP) required for fibril formation and difG is a fibril biogenesis regulator [31], [40]. frzS encodes a coiled-coil S-motility protein that interacts with MglA in vitro [41].…”

Section: Resultsmentioning

confidence: 99%

MasABK Proteins Interact with Proteins of the Type IV Pilin System to Affect Social Motility of Myxococcus xanthus

et al. 2013

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Gliding motility is critical for normal development of spore-filled fruiting bodies in the soil bacterium Myxococcus xanthus. Mutations in mgl block motility and development but one mgl allele can be suppressed by a mutation in masK, the last gene in an operon adjacent to the mgl operon. Deletion of the entire 5.5 kb masABK operon crippled gliding and fruiting body development and decreased sporulation. Expression of pilAGHI, which encodes type IV pili (TFP) components essential for social (S) gliding, several cryptic pil genes, and a LuxR family protein were reduced significantly in the Δmas mutant while expression of the myxalamide operon was increased significantly. Localization and two-hybrid analysis suggest that the three Mas proteins form a membrane complex. MasA-PhoA fusions confirmed that MasA is an integral cytoplasmic membrane protein with a ≈100 amino acid periplasmic domain. Results from yeast two-hybrid assays showed that MasA interacts with the lipoprotein MasB and MasK, a protein kinase and that MasB and MasK interact with one another. Additionally, yeast two-hybrid analysis revealed a physical interaction between two gene products of the mas operon, MasA and MasB, and PilA. Deletion of mas may be accompanied by compensatory mutations since complementation of the Δmas social gliding and developmental defects required addition of both pilA and masABK.

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“…The Frz pathway that controls the cell reversal frequency is one of the eight chemotaxis-like pathways in M. xanthus (Zusman et al, 2007); FrzCD itself is homologous to the chemoreceptors. Moreover, the Frz pathway crosstalks with other chemosensory pathways, such as the Dif pathway (Xu et al, 2008), which senses lipids and controls M. xanthus motility as well (Bonner et al, 2005;Xu et al, 2011). It is not surprising that M. xanthus exploits multiple sensing mechanisms to orchestrate formation of numerous types of population patterns at different stages of its social life cycle (Keane and Berleman, 2016).…”

Section: Discussionmentioning

confidence: 99%

Mathematical modeling of mechanosensing and contact-dependent motility coordination inMyxococcus xanthus

Chen

2022

Preprint

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Sensing and responding to mechanical cues in the environment are important for the survival and propagation of bacteria. A "social" bacterium, Myxococcus xanthus, which exhibits periodic cell reversals, modulates its reversal frequency in response to environmental mechanical cues, such as substrate stiffness and cell-cell contact. The cell-cell contact-dependent reversal control is particularly important for formation of complex multicellular patterns and structures during cooperative "social" behaviors in M. xanthus populations. Here we hypothesize that the gliding motility machinery of M. xanthus can sense the environmental mechanical cues during force generation and signal the cell's reversal control pathway to modulate the timing and frequency of cell reversal. To examine our hypothesis, we extend an existing mathematical model for periodic polarity switching (which mediates periodic cell reversal) in M. xanthus, and incorporate the experimentally suggested (i) intracellular dynamics of the gliding motors and (ii) interactions between the gliding motors and reversal regulators. The model results suggest the proper mode of interactions between the gliding motors and reversal regulators that can generate the observed increase of cell reversal frequency on stiffer substrates. Furthermore, the selected model predicts a cell reversal response to cell-cell contact, which is sufficient for generating the rippling wave, an important multicellular pattern in M. xanthus populations. Our model highlights a potential role of the gliding machinery of M. xanthus as a "mechanosensor" that transduces mechanical cues into a reversal control signal.

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DifA, a Methyl-Accepting Chemoreceptor Protein-Like Sensory Protein, Uses a Novel Signaling Mechanism to Regulate Exopolysaccharide Production inMyxococcus xanthus

Abstract: DifA is a methyl-accepting chemotaxis protein (MCP)-like sensory transducer that regulates exopolysaccharide (EPS) production in

Cited by 9 publications

References 47 publications

Mediation of Extracellular Polymeric Substances in Microbial Reduction of Hematite by Shewanella oneidensis MR-1

Mediation of Extracellular Polymeric Substances in Microbial Reduction of Hematite by Shewanella oneidensis MR-1

MasABK Proteins Interact with Proteins of the Type IV Pilin System to Affect Social Motility of Myxococcus xanthus

Mathematical modeling of mechanosensing and contact-dependent motility coordination inMyxococcus xanthus

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