Transcriptional changes involved in inhibition of biofilm formation by ε-Polylysine in Salmonella Typhimurium
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PROVIDER: PRJNA589476 | ENA |
REPOSITORIES: ENA
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Project description:Salmonella Typhimurium is one of the major foodborne pathogens due to its biofilm formation on food contact surfaces. A polymer of positively charged lysine, ε-Polylysine has been demonstrated to inhibit biofilm formation of both Gram-positive and -negative bacteria. To elucidate the mechanism for inhibition of biofilm formation by ε-Polylysine, transcriptional profiles were compared between the cells before and after treatment with ε-Polylysine in Salmonella Typhimurium. A genome-wide DNA microarray analysis was performed after cultivation in 0.1% bacto soytone in the presence of 0.001% ε-Polylysine at 30°C for 2 h. Genes involved in curli and cellulose production, quorum sensing, and flagellar motility were down-regulated, whereas genes associated with colanic acid synthesis were up-regulated. The data from microarray was validated by RT-qPCR. Furthermore, production of colanic acid in S. Typhimurium decreased in the presence of ε-Polylysine. The outcome of this study provides a basic understanding of the anti-biofilm mechanisms of ε-Polylysine and may contributes to develop new disinfectant to control biofilm during food manufacturing and storage.
2019-11-14 | GSE140300 | GEO
Project description:Most bacteria can form biofilms, which typically have a life cycle from cells initially attaching to a surface before aggregation and growth produces biomass and an extracellular matrix before finally cells disperse. To maximise fitness at each stage of this life cycle, and given the different events taking place within a biofilm, temporal regulation of gene expression is essential. We recently described the genes required for optimal fitness over time during biofilm formation in Escherichia coli using a massively parallel transposon mutagenesis approach called TraDIS-Xpress. We have now repeated this study in Salmonella enterica serovar Typhimurium to determine the similarities and differences in biofilm formation through time between these species. This work deepens understanding of the core requirements for biofilm formation in the Enterobacteriaceae whilst also identifying some genes with specialised roles in biofilm formation in each species.
2022-05-27 | E-MTAB-11765 | biostudies-arrayexpress
Project description:Upon biofilm formation, production of extracellular matrix components and alteration in physiology and metabolism allows bacteria to build up multicellular communities which can facilitate nutrient acquisition during unfavorable conditions and provide protection towards various forms of environmental stresses to individual cells. Thus, bacterial cells become tolerant against antimicrobials and the immune system within biofilms. In the current study, we evaluated the antibiofilm activity of the macrolides clarithromycin and azithromycin. Clarithromycin showed antibiofilm activity against rdar (red, dry and rough) biofilm formation of the gastrointestinal pathogen Salmonella typhimurium ATCC14028 Nalr at 1.56 µM subinhibitory concentration in standing culture and dissolved cell aggregates at 15 µM in a microaerophilic environment suggesting that the oxygen level affects the activity of the drug. Treatment with clarithromycin significantly decreased transcription and production of the rdar biofilm activator CsgD, with biofilm genes such as csgB and adrA to be consistently downregulated. While fliA and other flagellar regulon genes were upregulated, apparent motility was downregulated. RNA sequencing showed a holistic cell response upon clarithromycin exposure, whereby not only genes involved in the biofilm-related regulatory pathways, but also genes that likely contribute to intrinsic antimicrobial resistance, and the heat shock stress response were differentially regulated. Most significantly, clarithromycin exposure shifts the cells towards an apparent oxygen- and energy- depleted status, whereby the metabolism that channels into oxidative phosphorylation is downregulated, and energy gain by degradation of propane 1,2-diol, ethanolamine and L-arginine catabolism, potentially also to prevent cytosolic, is upregulated. This analysis will allow the subsequent identification of novel intrinsic antimicrobial resistance determinants.
2020-09-11 | GSE157695 | GEO
Project description:Salmonella enterica serovar Typhimurium (S. Typhimurium) infection triggers an inflammatory response that changes the concentration of luminal metabolites in the gut, resulting in a distinct environment from a healthy one. We recently demonstrated that S. Typhimurium possesses the ability to form biofilms within the host environment and responds to nitrate as a signaling molecule, enabling it to modulate the transition between sessile and planktonic states. To investigate whether S. Typhimurium utilizes additional metabolites to regulate its behavior, our study delved into the impact of inflammatory metabolites on biofilm formation. Employing a transcriptomic approach we unveiled that lactate enhances the transcription of flagella and invasion genes, highlighting the active role of lactate in modulating the transition of S. Typhimurium from biofilm to motile states. All these findings propose that, as occurring with nitrate, lactate is an inflammatory metabolite being used by S. Typhimurium to support virulence.
2024-10-23 | GSE255285 | GEO
Project description:Shewanella spp. possess a broad respiratory versatility, which contributes to the occupation of hypoxic/anoxic environmental or host-associated niches. Here we observed a strain-specific induction of biofilm formation in response to supplementation with the anaerobic electron acceptors dimethyl sulfoxide (DMSO) and nitrate in a panel of Shewanella algae isolates. The respiration-driven biofilm response is not observed in DMSO and nitrate reductase deletion mutants of the type strain S. algae CECT 5071, and can be restored upon complementation with the corresponding reductase operon(s) but not by an operon containing a catalytically inactive nitrate reductase. The distinct transcriptional changes, proportional to the effect of these compounds on biofilm formation, include cyclic di-GMP (c-di-GMP) turnover genes. In support, ectopic expression of the c-di-GMP phosphodiesterase YhjH of Salmonella Typhimurium but not its catalytically inactive variant decreased biofilm formation. The respiration-dependent biofilm response of S. algae may permit differential colonization of environmental or host niches.
2020-12-05 | GSE133627 | GEO
Project description:Two lineages of enterohemorrhagic (EHEC) Escherichia coli O157:H7 (EDL933, Stx1+ and Stx2+) and 86-24 (Stx2+) were investigated in regards to biofilm formation on an abiotic surface. Strikingly, EDL933 strain formed a robust biofilm while 86-24 strain formed no biofilm on either a polystyrene plate or a polyethylene tube. To identify the genetic mechanisms of different biofilm formation in two EHEC strains, DNA microarrays were first performed and phenotypic assays were followed. In the comparison of the EDL933 strain versus 86-24 strain, genes (csgBAC and csgDEFG) involved in curli biosynthesis were significantly induced while genes (trpLEDCB and mtr) involved in indole signaling were repressed. Additionally, a dozen of phage genes were differentially present between two strains. Curli assays using a Congo red plate and scanning electron microscopy corroborate the microarray data as the EDL 933 strain produces a large amount of curli, while 86-24 forms much less curli. Also, the indole production in the EDL933 was 2-times lower than that of 86-24. It was known that curli formation positively regulates and indole negatively regulates biofilm formation of EHEC. Hence, it appears that less curli formation and high indole production in the 86-24 strain are majorly responsible for no biofilm formation.
2011-01-19 | GSE19953 | GEO
Project description:Background: Biofilm formation by Salmonella species enhances the capacity of these pathogenic bacteria to survive stresses that are commonly encountered within food processing and during host infection. The persistence of Salmonella within the food chain has become a major health concern, as biofilms can serve as a reservoir to contaminate food products. While the molecular mechanisms required for the survival of bacteria on surfaces are not fully understood, transcriptional studies of other bacteria have demonstrated that biofilm growth triggers the expression of specific sets of genes, compared with planktonic cells. Until now, most transcriptomic studies of Salmonella have focused on the effect of infection-relevant stressors on virulence and on comparing mutant and wild-type (WT). However little is known about the physiological responses taking place inside a Salmonella biofilm. Results: We have determined the transcriptomic and proteomic profiles of biofilms of Salmonella enterica serovar Typhimurium. We discovered that 124 of detectable proteins were differentially expressed in the biofilm compared with planktonic cells, and that 10% (433 genes) of S. Typhimurium genes showed a biofilm-specific pattern of transcription (i.e. a 2-fold or more change in the biofilm compared with planktonic cells). The genes that were significantly up-regulated implicated specific cellular processes in biofilm development including amino acid metabolism, cell motility, global regulation and tolerance to stress. We found that the most highly down-regulated genes in the biofilm were located on Salmonella Pathogenicity Island 2 (SPI2), but that a functional SPI2 secretion system regulator (ssrA) was required for WT biofilm formation. We identified STM0341 as a gene of unknown function that was needed for WT biofilm growth. Genes involved in tryptophan (trp) biosynthesis and transport were up-regulated in the biofilm. Deletion of trpE led to a decrease in bacterial attachment and we show that this biofilm defect is restored by exogenous tryptophan or indole. Conclusion: Biofilm growth of S. Typhimurium causes distinct changes in gene and protein expression. Our results show that aromatic amino acids make an important contribution to biofilm formation, and reveal that SPI2 genes, required for virulence in host cells, show opposing patterns of expression to biofilm-specific genes in S. Typhimurium.
2009-12-14 | GSE17246 | GEO
Project description:In Staphylococcus aureus, the role of the GGDEF domain containing protein GdpS remains poorly understood. Previous studies reported that gdpS mutant strains had decreased biofilm formation due to changes in icaADBC expression that were independent of cyclic-di-GMP levels. We deleted gdpS in three unrelated S. aureus isolates, and analyzed the resultant mutants for alterations in biofilm formation, metabolism and transcription. Dynamic imaging during biofilm development showed that GdpS inhibited early biofilm formation in only two out of the three strains examined, without affecting bacterial survival. However, quantification of biofilm formation using crystal violet staining revealed that inactivation of gdpS affected biofilm formation in all three studied strains. Extraction of metabolites from S. aureus cells confirmed the absence of cyclic-di-GMP, suggesting that biofilm formation in this species differs from that in other Gram-positive organisms. In addition, targeted mutagenesis demonstrated that the GGDEF domain was not required for GdpS activity. Transcriptomic analysis revealed that the vast majority of GGDEF-regulated genes were involved in virulence, metabolism, cell wall biogenesis and eDNA release. Finally, expression of lrgAB or deletion of cidABC in a strain lacking gdpS confirmed the role of GdpS on regulation of eDNA production that occurred without an increase in cell autolysis. In summary, S. aureus GdpS contributes to cell-to-cell interactions during early biofilm formation by influencing expression of lrgAB and cidABC mediated eDNA release. We conclude that GdpS acts as a negative regulator of eDNA release. Three strains UAMS-1, SA113 and SA564 were used in this study to compare wt with gdpS mutant after 5 hours of growth in static conditions (biofilm formation).
2014-06-30 | E-GEOD-48656 | biostudies-arrayexpress
Project description:The study is about the role of Bacteroides thetaiotaomicron in the human gut microbiota, specifically its ability to form biofilms in response to bile salts. The study found that bile induces the expression of certain efflux pumps, and inhibiting these pumps impairs biofilm formation. Among the induced pumps, the BipABC pump is crucial for biofilm formation as it is involved in the efflux of magnesium, which affects the biofilm's extracellular matrix and structure. This discovery sheds light on how intestinal chemical cues, like bile salts, regulate biofilm formation in B. thetaiotaomicron, a significant gut symbiont.
2024-03-19 | E-MTAB-13460 | biostudies-arrayexpress
Project description:In Staphylococcus aureus, the role of the GGDEF domain containing protein GdpS remains poorly understood. Previous studies reported that gdpS mutant strains had decreased biofilm formation due to changes in icaADBC expression that were independent of cyclic-di-GMP levels. We deleted gdpS in three unrelated S. aureus isolates, and analyzed the resultant mutants for alterations in biofilm formation, metabolism and transcription. Dynamic imaging during biofilm development showed that GdpS inhibited early biofilm formation in only two out of the three strains examined, without affecting bacterial survival. However, quantification of biofilm formation using crystal violet staining revealed that inactivation of gdpS affected biofilm formation in all three studied strains. Extraction of metabolites from S. aureus cells confirmed the absence of cyclic-di-GMP, suggesting that biofilm formation in this species differs from that in other Gram-positive organisms. In addition, targeted mutagenesis demonstrated that the GGDEF domain was not required for GdpS activity. Transcriptomic analysis revealed that the vast majority of GGDEF-regulated genes were involved in virulence, metabolism, cell wall biogenesis and eDNA release. Finally, expression of lrgAB or deletion of cidABC in a strain lacking gdpS confirmed the role of GdpS on regulation of eDNA production that occurred without an increase in cell autolysis. In summary, S. aureus GdpS contributes to cell-to-cell interactions during early biofilm formation by influencing expression of lrgAB and cidABC mediated eDNA release. We conclude that GdpS acts as a negative regulator of eDNA release.
2014-06-30 | GSE48656 | GEO