The Role of the Membrane in the Bioenergetics of Bacterial Cells

2018 ◽  
pp. 53-71
Author(s):  
Terry A. Krulwich ◽  
Arthur A. Guffanti ◽  
Kenneth G. Mandel
Keyword(s):  
Bacterial Cells

scholarly journals Spo0A Suppresses sin Locus Expression in Clostridioides difficile

mSphere ◽  
2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Babita Adhikari Dhungel ◽  
Revathi Govind
Keyword(s):  
Diarrheal Disease ◽  
Toxin Production ◽  
The United States ◽  
Upstream Region ◽  
Pcr Analysis ◽  
Bacterial Cells ◽  
Master Regulator ◽  
Content Type ◽  
Clostridioides Difficile

ABSTRACT Clostridioides difficile is the leading cause of nosocomial infection and is the causative agent of antibiotic-associated diarrhea. The severity of the disease is directly associated with toxin production, and spores are responsible for the transmission and persistence of the organism. Previously, we characterized sin locus regulators SinR and SinR′ (we renamed it SinI), where SinR is the regulator of toxin production and sporulation. The SinI regulator acts as its antagonist. In Bacillus subtilis, Spo0A, the master regulator of sporulation, controls SinR by regulating the expression of its antagonist, sinI. However, the role of Spo0A in the expression of sinR and sinI in C. difficile had not yet been reported. In this study, we tested spo0A mutants in three different C. difficile strains, R20291, UK1, and JIR8094, to understand the role of Spo0A in sin locus expression. Western blot analysis revealed that spo0A mutants had increased SinR levels. Quantitative reverse transcription-PCR (qRT-PCR) analysis of its expression further supported these data. By carrying out genetic and biochemical assays, we show that Spo0A can bind to the upstream region of this locus to regulates its expression. This study provides vital information that Spo0A regulates the sin locus, which controls critical pathogenic traits such as sporulation, toxin production, and motility in C. difficile. IMPORTANCE Clostridioides difficile is the leading cause of antibiotic-associated diarrheal disease in the United States. During infection, C. difficile spores germinate, and the vegetative bacterial cells produce toxins that damage host tissue. In C. difficile, the sin locus is known to regulate both sporulation and toxin production. In this study, we show that Spo0A, the master regulator of sporulation, controls sin locus expression. Results from our study suggest that Spo0A directly regulates the expression of this locus by binding to its upstream DNA region. This observation adds new detail to the gene regulatory network that connects sporulation and toxin production in this pathogen.

scholarly journals GC-TOF/MS-based metabolomics analysis to investigate the changes driven by N-Acetylcysteine in the plant-pathogen Xanthomonas citri subsp. citri

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Simone Cristina Picchi ◽  
Mariana de Souza e Silva ◽  
Luiz Leonardo Saldanha ◽  
Henrique Ferreira ◽  
Marco Aurélio Takita ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cell Proliferation ◽  
Plant Pathogen ◽  
Model Organism ◽  
Citrus Canker ◽  
Bacterial Cells ◽  
Xanthomonas Citri ◽  
Canker Disease ◽  
Potential Use

AbstractN-Acetylcysteine (NAC) is an antioxidant, anti-adhesive, and antimicrobial compound. Even though there is much information regarding the role of NAC as an antioxidant and anti-adhesive agent, little is known about its antimicrobial activity. In order to assess its mode of action in bacterial cells, we investigated the metabolic responses triggered by NAC at neutral pH. As a model organism, we chose the Gram-negative plant pathogen Xanthomonas citri subsp. citri (X. citri), the causal agent of citrus canker disease, due to the potential use of NAC as a sustainable molecule against phytopathogens dissemination in citrus cultivated areas. In presence of NAC, cell proliferation was affected after 4 h, but damages to the cell membrane were observed only after 24 h. Targeted metabolite profiling analysis using GC–MS/TOF unravelled that NAC seems to be metabolized by the cells affecting cysteine metabolism. Intriguingly, glutamine, a marker for nitrogen status, was not detected among the cells treated with NAC. The absence of glutamine was followed by a decrease in the levels of the majority of the proteinogenic amino acids, suggesting that the reduced availability of amino acids affect protein synthesis and consequently cell proliferation.

scholarly journals A novel calcium-concentrating compartment drives biofilm formation and persistent infections

2020 ◽  
Author(s):  
Alona Keren-Paz ◽  
Malena Cohen-Cymberknoh ◽  
Dror Kolodkin-Gal ◽  
Iris Karunker ◽  
Simon Dersch ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Calcium Uptake ◽  
Molecular Mechanisms ◽  
Model Organism ◽  
Bacterial Cells ◽  
Mineral Layer ◽  
Cellular Compartment ◽  
Persistent Infections ◽  
Cellular Metal

AbstractBacterial biofilms produce a robust internal mineral layer, composed of calcite, which strengthens the colony and protects the residing bacteria from antibiotics. In this work, we provide evidence that the assembly of a functional mineralized macro-structure begins with mineral precipitation within a defined cellular compartment in a differentiated subpopulation of cells. Transcriptomic analysis of a model organism, Bacillus subtilis, revealed that calcium was essential for activation of the biofilm state, and highlighted the role of cellular metal homeostasis and carbon metabolism in biomineralization. The molecular mechanisms promoting calcite formation were conserved in pathogenic Pseudomonas aeruginosa biofilms, resulting in formation of calcite crystals tightly associated with bacterial cells in sputum samples collected from cystic fibrosis patients. Biomineralization inhibitors targeting calcium uptake and carbonate accumulation significantly reduced the damage inflicted by P. aeruginosa biofilms to lung tissues. Therefore, better understanding of the conserved molecular mechanisms promoting biofilm calcification can path the way to the development of novel classes of antibiotics to combat otherwise untreatable biofilm infections.

Microbial dispersal throgh dead-end cavities

2021 ◽  
Author(s):  
David Scheidweiler ◽  
Ankur Deep Bordoloi ◽  
Pietro de Anna
Keyword(s):  
Porous Media ◽  
Time Lapse ◽  
Breakthrough Curves ◽  
Bacterial Cells ◽  
Dispersal Patterns ◽  
Microbial Life ◽  
Sedimentary Environments ◽  
Escherichia Coli Cells ◽  
Dead End

<p>Predicting dispersal patterns is important to understand microbial life in porous media as soils and sedimentary environments. We studied active and passive dispersal of bacterial cells in porous media characterized by two main pore features: fast channels and dead-end cavities. We combined experiments with microfluidic devices and time-lapse microscopy to track individual bacterial trajectories and measure the breakthrough curves and pore scale bacterial abundance. Escherichia coli cells dispersed more efficiently than the non-motile mutants showing a different retention in the dead-end pores. Our findings highlight the role of diffusion dominated dead-end pores on the dispersal of microorganisms in porous media.</p>

Effect of GO on bacterial cells: Role of the medium type and electrostatic interactions

2019 ◽  
Vol 99 ◽  
pp. 275-281 ◽  
Author(s):  
Alexander Gusev ◽  
Olga Zakharova ◽  
Inna Vasyukova ◽  
Dmitry S. Muratov ◽  
Iaroslav Rybkin ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Bacterial Cells ◽  
Medium Type

Biotransformation of Metalloporphyrins by Microorganisms Isolated from Organic-Rich Metal-Bearing Black Shale

2009 ◽  
Vol 71-73 ◽  
pp. 709-712 ◽  
Author(s):  
Renata Matlakowska ◽  
Aleksandra Sklodowska
Keyword(s):  
Carbon Source ◽  
Black Shale ◽  
Bacterial Cells ◽  
Indigenous Microorganisms ◽  
Copper Tailings ◽  
Naturally Occurring ◽  
Laboratory Cultures ◽  
Potential Use ◽  
Sole Energy

Indigenous microorganisms isolated from organic-rich copper-bearing black shale from the Fore-Sudetic Monocline were able to transform naturally occurring metalloporphyrins in laboratory cultures. It was also demonstrated that these bacteria can utilize synthetic metalloporphyrins as the sole energy and carbon source. The first step in metalloporphyrin biotransformation was identified as the highly effective bioaccumulation of these compounds in bacterial cells. The ability of both living and dead cells to biosorb metalloporphyrins was also confirmed. Besides contributing to the important biogeochemical role of these microorganisms in the environment, their biotransformation activities are of potential use in the bioremediation of copper tailings as well as in the recovery of metals from organic-rich black shale ore, which is not possible using traditional hydrometallurgical procedures.

scholarly journals Rules and Exceptions: The Role of Chromosomal ParB in DNA Segregation and Other Cellular Processes

2020 ◽  
Vol 8 (1) ◽  
pp. 105 ◽  
Author(s):  
Adam Kawalek ◽  
Pawel Wawrzyniak ◽  
Aneta Agnieszka Bartosik ◽  
Grazyna Jagura-Burdzy
Keyword(s):  
Bacterial Species ◽  
Regulation Of Gene Expression ◽  
Replication Initiation ◽  
Bacterial Cells ◽  
Dna Segregation ◽  
Cellular Processes ◽  
Chromosome Partitioning ◽  
Structural Maintenance Of Chromosome ◽  
Dna Partitioning

The segregation of newly replicated chromosomes in bacterial cells is a highly coordinated spatiotemporal process. In the majority of bacterial species, a tripartite ParAB-parS system, composed of an ATPase (ParA), a DNA-binding protein (ParB), and its target(s) parS sequence(s), facilitates the initial steps of chromosome partitioning. ParB nucleates around parS(s) located in the vicinity of newly replicated oriCs to form large nucleoprotein complexes, which are subsequently relocated by ParA to distal cellular compartments. In this review, we describe the role of ParB in various processes within bacterial cells, pointing out interspecies differences. We outline recent progress in understanding the ParB nucleoprotein complex formation and its role in DNA segregation, including ori positioning and anchoring, DNA condensation, and loading of the structural maintenance of chromosome (SMC) proteins. The auxiliary roles of ParBs in the control of chromosome replication initiation and cell division, as well as the regulation of gene expression, are discussed. Moreover, we catalog ParB interacting proteins. Overall, this work highlights how different bacterial species adapt the DNA partitioning ParAB-parS system to meet their specific requirements.

The sodium pump in the evolution of animal cells

1995 ◽  
Vol 349 (1329) ◽  
pp. 263-269 ◽  
Keyword(s):  
Sodium Pump ◽  
Transport Systems ◽  
Primary Role ◽  
Bacterial Cells ◽  
Electrochemical Gradient ◽  
Animal Cells ◽  
Osmotic Balance ◽  
Energy Consuming ◽  
P Type

Plant cells and bacterial cells are surrounded by a massive cellulose wall, which constrains their high internal osmotic pressure (tens of atmospheres). Animal cells, in contrast, are in osmotic equilibrium with their environment, have no restraining surround, can take on a variety of shapes and change these from moment to moment. This osmotic balance is achieved by the action of the energy-consuming sodium pump, one of the P-type ATPase transport protein family, members of which are indeed also found in bacteria. The pump’s action brings about a transmembranal electrochemical gradient of sodium ions, harnessed in a range of transport systems that couple the dissipation of this gradient to establishing a gradient of the coupled substrate. The primary role of the sodium pump as a regulator of cell volume has evolved to provide the basis for an enormous variety of physiological functions.

Anti-inflammatory properties of probiotic bacteria on Salmonella-induced IL-8 synthesis in enterocyte-like Caco-2 cells

2010 ◽  
Vol 1 (2) ◽  
pp. 121-130 ◽  
Author(s):  
J. Malago ◽  
P. Tooten ◽  
J.F. Koninkx
Keyword(s):  
Tissue Damage ◽  
Protective Role ◽  
Bifidobacterium Bifidum ◽  
Probiotic Bacterium ◽  
Hsp70 Expression ◽  
Bacterial Cells ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Inflammatory Reactions ◽  
Mediated Reduction

Invasion of the gut by pathogenic Salmonella leads to production of IL-8 that initiates inflammatory reactions to combat the bacterium. However, its persistent production causes tissue damage and interventions that suppress IL-8 production prevent tissue damage. We hypothesised that probiotics could mediate their benefits via inhibition of IL-8 synthesis. Caco-2 cells were infected with probiotic Bifidobacterium infantis W52, Lactobacillus casei W56, Lactococcus lactis W58, Lactobacillus acidophilus W70, Bifidobacterium bifidum W23, or Lactobacillus salivarius W24 or pathogenic Salmonella enterica serovar Enteritidis 857 at 0, 0.2, 1, 2, 10, 20, 100 or 200 bacterial cells/Caco-2 cell for 1 hour. Cells were also exposed to a combination of one probiotic bacterium (200 bacterial cells/Caco-2 cell) and the graded numbers of Salmonella as either co-incubation (1 hour) or pre-incubation of the probiotic bacterium (1 hour) followed by Salmonella (1 hour). The cells recovered for 2 or 24 hours. IL-8 and Hsp70 were determined by ELISA and Western blot respectively. Both probiotics and Salmonella induced a dose- and time-dependent synthesis of IL-8 but probiotics induced far lower IL-8 levels than Salmonella. The Salmonella-induced IL-8 was significantly suppressed by B. infantis W52, L. casei W56 and L. lactis W58 at low numbers of Salmonella (0.2 to 20 bacterial cells/Caco-2 cell) and within 2 hours of recovery. The observed probiotic-mediated reduction in IL-8 secretion was transient, and lost after a few hours. In addition, these three probiotics induced a significant increase in Hsp70 expression while L. acidophilus W70, B. bifidum W23 and L. salivarius W24 induced a weak Hsp70 expression and could not suppress the Salmonella-induced IL-8 synthesis. We conclude that suppression of Salmonella-induced IL-8 synthesis by Caco-2 cells is exhibited by probiotics that induce expression of Hsp70, suggesting that the protective role of probiotics could be mediated, at least in part, via Hsp70 expression. This suppression is limited to a low number of infecting pathogenic Salmonella.

scholarly journals BaeSR, Involved in Envelope Stress Response, Protects against Lysogenic Conversion by Shiga Toxin 2-Encoding Phages

2015 ◽  
Vol 83 (4) ◽  
pp. 1451-1457 ◽  
Author(s):  
Lejla Imamovic ◽  
Alexandre Martínez-Castillo ◽  
Carmen Benavides ◽  
Maite Muniesa
Keyword(s):  
Stress Responses ◽  
Shiga Toxin ◽  
Phage Infection ◽  
Bacterial Cells ◽  
Content Type ◽  
Signaling Systems ◽  
E Coli ◽  
Envelope Stress ◽  
Lysogenic Conversion

Infection and lysogenic conversion with Shiga toxin-encoding bacteriophages (Stx phages) drive the emergence of new Shiga toxin-producingEscherichia colistrains. Phage attachment to the bacterial surface is the first stage of phage infection. Envelope perturbation causes activation of envelope stress responses in bacterial cells. Although many external factors are known to activate envelope stress responses, the role of these responses in the phage-bacterium interaction remains unexplored. Here, we investigate the link between three envelope signaling systems inE. coli(RcsBC, CpxAR, and BaeSR) and Stx2 phage infection by determining the success of bacterial lysogenic conversion. For this purpose,E. coliDH5α wild-type (WT) and mutant strains lacking RcsBC, CpxAR, or BaeSR signaling systems were incubated with a recombinant Stx2 phage (933W). Notably, the number of lysogens obtained with the BaeSR mutant was 5 log10units higher than with the WT, and the same differences were observed when using 7 different Stx2 phages. To assess whether the membrane receptor used by Stx phages, BamA, was involved in the differences observed,bamAgene expression was monitored by reverse transcription-quantitative PCR (RT-qPCR) in all host strains. A 4-fold-higherbamAexpression level was observed in the BaeSR mutant than in the WT strain, suggesting that differential expression of the receptor used by Stx phages accounted for the increase in the number of lysogenization events. Establishing the link between the role of stress responses and phage infection has important implications for understanding the factors affecting lysogenic conversion, which drives the emergence of new pathogenic clones.

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