pH-dependent genotypic and phenotypic variability in Oleidesulfovibrio alaskensis G20

Applied and Environmental Microbiology, Год журнала: 2025, Номер unknown

Опубликована: Март 26, 2025

ABSTRACT Sulfate-reducing bacteria (SRB) exhibit versatile metabolic adaptability with significant flexibility influenced by pH fluctuations, which play a critical role in biogeochemical cycles. In this study, we used model SRB, Oleidesulfovibrio alaskensis G20, to determine the temporal effects of variations (pH 6, 7, and 8) on both growth dynamics gene expressions. The specific rate at 6 (0.014 h −1 ) closely matched that 7 (0.016 ), while 8 exhibited lower (0.010 ). Lactate consumption peaked (0.35 mM lactate.h declined (0.09 Significant hydrogen production was evident under acidic alkaline conditions. Gene expression studies revealed ATPases function as proton pumps, hydrogenases mediate reversible proton-to-hydrogen conversion. Sulfate energy metabolism act electron acceptors donors, amino acid synthesis regulates basic acids mitigate stress. Downregulation FtsZ suggests impaired division, correlating slightly longer lengths (~2 µm), upregulation divisome proteins efficient division processes, aligning shorter (~1.8 µm). This study will facilitate employment O. G20 extreme environments, enhancing its effectiveness optimizing bioremediation anaerobic digestion processes. IMPORTANCE essential roles global sulfur carbon cycling are for However, detailed genotypic phenotypic responses SRB varying conditions limited. addresses gap examining pH-dependent genetic adaptations revealing key mechanisms regulating hydrogenase ATPase activities, cell extracellular polymeric substance formation. These findings provide new insights into how maintains homeostasis, showcasing their ability survive environments. Furthermore, reveals characteristics directly aid engineer industrial effluent management systems, bioremediation, dissolved heavy metal recovery. By elucidating dynamic response varied research provides foundation resilience performance SRB-based paving way improved environmental applications.

Язык: Английский

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Pattern formation in E . coli through negative chemotaxis: Instability, condensation, and merging

Physical Review Research, Год журнала: 2025, Номер 7(2)

Опубликована: Апрель 28, 2025

Motile bacteria can migrate along chemical gradients in a process known as chemotaxis. When exposed to uniform environmental stress, cells coordinate their chemotactic responses form millimeter-sized condensates containing hundreds of thousands motile cells. In this study, we combined experiments with mathematical modeling based on modified Keller-Segel equations investigate the dynamics collective behavior across three distinct timescales: shortest timescale, where spatial instability emerges; an intermediate quasistationary bacterial form; and finally, longer during which neighboring accumulations coalesce. The model closely agrees experimental results, quantitatively capturing observed instability, shape mature condensates, coalescence dynamics. Specifically, found that force between decays exponentially distance due screening effects. We suggest presented here could describe more broadly stress-induced condensation mediated by Published American Physical Society 2025

Язык: Английский

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The Interplay of AphB and CadC to Activate Acid Resistance of Vibrio campbellii

Journal of Bacteriology, Год журнала: 2023, Номер 205(4)

Опубликована: Март 15, 2023

Bacteria have evolved different systems to sense and adapt acid stress. For example, Vibrio campbellii, a marine pathogen for invertebrates, encounters acidic conditions in the digestive glands of shrimp. The main resistance system V. campbellii is Cad system, which activated when cells are low-pH, amino acid-rich environment. consists pH-responsive transcriptional activator CadC, lysine decarboxylase CadA, lysine/cadaverine antiporter CadB. In many species, LysR-type regulator AphB involved regulation but its precise role unclear. Here, we examined vivo vitro context activation. At low pH, an aphB deletion mutant was less able grow survive compared with wild-type because it did not excrete sufficient alkaline cadaverine increase extracellular pH. found upregulate transcription cadC, thereby increasing protein copy number per cell. Moreover, itself shown be pH-sensor, binding cadC promoter increased under as by surface plasmon resonance spectroscopy. By monitoring activation over wide range pH values, that AphB-mediated upregulation only adjusts CadC numbers depending on stress strength, also affects response individual thus degree heterogeneous population. IMPORTANCE Acid important property neutralophilic enteric bacteria such Escherichia, Yersinia, Salmonella, Vibrio. To counteract threats, various activates acid-resistance system. pH-sensor. expression upregulated achieve maximum components studies demonstrate binds more tightly DNA interplay two activators allows tight control activity

Язык: Английский

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Why does increased microbial fermentation in the human colon shift toward butyrate?

AIMS Microbiology, Год журнала: 2024, Номер 10(2), С. 311 - 319

Опубликована: Янв. 1, 2024

The microbial community of the human large intestine mainly ferments dietary fiber to short chain fatty acids (SCFAs), which are efficiently absorbed by host. three major SCFAs (acetate, propionate, and butyrate) have different fates within body effects on health. A recent analysis 10 volunteer studies established that proportions these SCFA in fecal samples significantly shifted towards butyrate as overall concentration increased. Butyrate plays a key role gut health is preferentially utilized an energy source colonic epithelium. Here we discuss possible mechanisms underlie this 'butyrate shift'; include selection for butyrate-producing bacteria microbiota certain types fiber, possibility additional formation from lactate acetate metabolite cross-feeding. However, crucial factor appears be pH proximal colon, decreases concentrations increase. mildly acidic has been shown important impact competition stoichiometry production. Understanding complex interactions greatly aided refinement theoretical models assume small number (10) functional groups (MFGs).

Язык: Английский

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Methods for studying microbial acid stress responses: from molecules to populations

FEMS Microbiology Reviews, Год журнала: 2024, Номер 48(5)

Опубликована: Май 17, 2024

The study of how micro-organisms detect and respond to different stresses has a long history producing fundamental biological insights while being simultaneously significance in many applied microbiological fields including infection, food drink manufacture, industrial environmental biotechnology. This is well-illustrated by the large body work on acid stress. Numerous methods have been used understand impacts low pH growth survival micro-organisms, ranging from studies single cells heterogeneous populations, molecular or biophysical computational, well-understood model organisms poorly defined complex microbial consortia. Much be gained an increased general awareness these methods, so present review looks at examples that resistance, tolerance, stress responses, they can lead to, as well some problems involved using them. We hope this will interest both within beyond research community.

Язык: Английский

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Response of Escherichia coli to Acid Stress: Mechanisms and Applications—A Narrative Review

Microorganisms, Год журнала: 2024, Номер 12(9), С. 1774 - 1774

Опубликована: Авг. 28, 2024

Change in pH growth conditions is the primary stress for most neutralophilic bacteria, including model microorganism

Язык: Английский

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Comparative analysis of cosmetic ingredient degradation: Fungal vs. bacterial activity in diverse media as potential replacements

International Biodeterioration & Biodegradation, Год журнала: 2024, Номер 191, С. 105795 - 105795

Опубликована: Апрель 22, 2024

The study explores the resilience of fungi and bacteria in degrading three selected cosmetic ingredients, butylated hydroxy anisole (BHA), benzophenone 3 (BZ3), decamethylcyclopentasiloxane (D4), across different pH levels temperatures. Understanding microbial adaptability optimizing degradation conditions are crucial for effective biodegradation processes, given influence temperature on activity. Trametes versicolor Pseudomonas aeruginosa were chosen as representative fungal bacterial species studies, with synthetic wastewater utilized alongside traditional growth media. Our research pioneers utilization media, recognizing its untapped potential enhancing efficiency. By subjecting to environmental stressors, we illuminate adaptive strategies employed by these organisms, processes. hypothesis posited that would enhance efficiency, while stressors elucidate their adaptability. Two temperatures (25 °C & 37 °C) two (2.5 6.89) examined mimic real-world conditions, employing advanced techniques like Nuclear Magnetic Resonance (NMR) assess Results revealed successful degradation, particularly complete D4 partial PDB media at 25 °C. At °C, BHA BZ3 occurred higher rates wastewater. However, was incomplete, especially Leveraging a medium targeted multiple pollutants specific represents an innovative advancement methodologies, highlighting importance

Язык: Английский

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Motility-activating mutations upstream of flhDC reduce acid shock survival of Escherichia coli

Microbiology Spectrum, Год журнала: 2024, Номер 12(6)

Опубликована: Апрель 23, 2024

ABSTRACT Many neutralophilic bacterial species try to evade acid stress with an escape strategy, which is reflected in the increased expression of genes coding for flagellar components. Extremely acid-tolerant bacteria, such as Escherichia coli , survive strong stress, e.g., stomach vertebrates. Recently, we were able show that induction motility E. strictly dependent on degree i.e., they are induced under mild but not severe stress. However, it was known what extent fine-tuned related fitness and ability periods shock. In this study, demonstrate FlhDC, master regulator flagellation, inversely correlated shock survival . We encountered phenomenon when analyzing mutants from Keio collection, flhDC altered by insertion sequence element. These results suggest a trade-off between tolerance motility. IMPORTANCE extremely acid-resistant, crucial gastrointestinal tract systematically studied response acidic conditions using Ribo-Seq RNA-Seq. found at pH 5.8 4.4, indicating stress-dependent synthesis motility-activating mutations upstream encoding flagella genes, reduce Furthermore, inverse correlation chromosomal isopropyl β-D-thio-galactopyranoside (IPTG)-inducible promoter sampling differentially motile subpopulations swim agar plates. reveal previously undiscovered differentiation into subpopulations, driven integration elements.

Язык: Английский

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Collective condensation and auto-aggregation of Escherichia coli in uniform acidic environments

Communications Biology, Год журнала: 2024, Номер 7(1)

Опубликована: Авг. 21, 2024

Chemotaxis-the movement of cells along chemical gradients-leads to collective behaviors when coordinate their movements. Here, using Escherichia coli as a model, we demonstrate distinct type bacterial response in acidic environments containing organic acids. Bacterial populations immersed such collectively condensed into millimeter-sized focal points. Furthermore, this condensation fostered the formation small, tightly packed cell aggregates, resembling non-surface-attached biofilms. These aggregates were physically displaced by free-swimming condensing cells, leading segregation two populations. relied on feedback between tendency these bacteria neutralize pH and chemotactic repulsion from low pH. Sustained occurred occupied only part environment, either dynamically or due physical constraints. Such can mitigate acid stress more efficiently, principle that may be applicable other conditions.

Язык: Английский

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Molecular mechanism of proteolytic cleavage-dependent activation of CadC-mediated response to acid in E. coli

Communications Biology, Год журнала: 2024, Номер 7(1)

Опубликована: Окт. 16, 2024

Colonizing in the gastrointestinal tract, Escherichia coli confronts diverse acidic challenges and evolves intricate acid resistance strategies for its survival. The lysine-mediated decarboxylation (Cad) system, featuring lysine decarboxylase CadA, lysine/cadaverine antiporter CadB, transcriptional activator CadC, plays a crucial role E. coli's adaptation to moderate stress. While activation of one-component system CadC subsequent upregulation cadBA operon response presence have been proposed, molecular mechanisms governing transition from an inactive active state remain elusive. Under neutral conditions, is inhibited by forming complex with lysine-specific permease LysP, stabilized this disulfide bond. Our study unveils that, environment, bond reduced isomerase DsbC, exposing R184 periplasmic proteases, namely DegQ DegP. Cleavage at DegP generates N-terminal DNA-binding domain which binds promoter, resulting upregulated transcription cadA cadB genes. Upon activation, CadA decarboxylates lysine, producing cadaverine, subsequently transported extracellularly CadB. We propose that accumulating cadaverine gradually pH-sensing domain, preventing cleavage as feedback mechanism. identification DegP, DegQ, DsbC completes comprehensive roadmap regulation Cad stress coli.

Язык: Английский

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