Project description:Polyphosphate accumulating organisms are responsible for enhanced biological phosphate removal from wastewater, where they grow embedded in a matrix of extracellular polymeric substances. Little is known about the composition and dynamics of those proteins and their production by the different microorganisms. Tomás-Martínez et al., (2022) studied the turnover of proteins and polysaccharides in extracellular polymeric fractions of an enrichment culture of polyphosphate accumulating organisms using an anaerobic-aerobic sequencing batch reactor simulating EBPR conditions. Finally, the carbon source was switched to 13C-labelled acetate to study the protein turnover. Samples were collected at the end of each aerobic phase.
2022-12-25 | PXD036522 | Pride
Project description:Extracellular polymeric substances associated to antibiotic resistance genes in microalgae-bacteria systems
Project description:Incomplete antibiotic removal in pharmaceutical wastewater treatment plants (PWWTPs) could lead to the development and spread of antibiotic-resistant bacteria (ARBs) and genes (ARGs) in the environment, posing a growing public health threat. In this study, two multiantibiotic-resistant bacteria, Ochrobactrum intermedium (N1) and Stenotrophomonas acidaminiphila (N2), were isolated from the sludge of a PWWTP in Guangzhou, China. The N1 strain was highly resistant to ampicillin, cefazolin, chloramphenicol, tetracycline, and norfloxacin, while the N2 strain exhibited high resistance to ampicillin, chloramphenicol, and cefazolin. Whole-genome sequencing revealed that N1 and N2 had genome sizes of 0.52 Mb and 0.37 Mb, respectively, and harbored 33 and 24 ARGs, respectively. The main resistance mechanism in the identified ARGs included efflux pumps, enzymatic degradation, and target bypass, with the N1 strain possessing more multidrug-resistant efflux pumps than the N2 strain (22 vs 12). This also accounts for the broader resistance spectrum of N1 than of N2 in antimicrobial susceptibility tests. Additionally, both genomes contain numerous mobile genetic elements (89 and 21 genes, respectively) and virulence factors (276 and 250 factors, respectively), suggesting their potential for horizontal transfer and pathogenicity. Overall, this research provides insights into the potential risks posed by ARBs in pharmaceutical wastewater and emphasizes the need for further studies on their impact and mitigation strategies.
Project description:Biofilms with immobilized cells in industrial fermentation are beneficial. Encased in extracellular polymeric substance, cells forming biofilms are regulated by various factors. Nitric oxide (NO), as a signaling molecule, recognized as quorum sensing molecule regulating microbe biofilm formation. Regulation mechanisms of NO on bacteria biofilm have been studied extensively and deeply, while on fungus are rarely studied. In this study, we observed that low concentration of NO enhanced S. cerevisiae biofilm formation. Transcriptional and proteomic analysis revealed that transcription factor MAC1 was activated in biofilm cells under NO treatment. Overexpressed MAC1 increased yeast biofilm formation bypassing regulating the expression level of FLO11. Increased copper and iron contents in NO treated and MAC1 overexpressed cells were not responsible for increased biofilm formation. Among six downstream genes of MAC1, overexpressed CTR1 contributed yeast biofilm formation. Moreover, MAC1 and CTR1 contributed to biofilm cells ethanol resistance resulting from enhanced biofilm. The role of CTR1 protein in yeast biofilm formation may result from its hydrophobic residues in N-terminal extracellular domain. These findings suggested a NO-mediated biofilm formation mechanism that NO regulated expression levels of CTR1 through activating its transcription factor MAC1, leading enhanced biofilm formation.
Project description:LubriShieldTM - a novel permanent coating was invented, and evenly applied to both the internal and external surfaces of indwelling urinary Foley catheters. Without releasing active substances, it effectively prevented pathogens from producing biofilm. The coating was superhydrophilic and incorporated a proprietary anti-fouling ligand, which created a surface that significantly inhibited up to 99% of colonizing uropathogens from forming biofilm for the duration of use without any microbial killing (p< 0.001).RNA-seq analysis revealed that gene expression associated with microbial extracellular polymeric substances formation was significantly downregulated on the coated surfaces. Additionally, microorganisms adhering to LubriShieldTM coated catheters were 78% more susceptible to antibiotics compared to those on uncoated silicone catheters (p=0.004).
Project description:Duckweed-associated plant growth-promoting bacteria (PGPB) have attracted considerable attention for enhancing duckweed biomass production; however, the mechanisms underlying strain-specific plant growth promotion remain largely unknown. Here, we compared the effects of two duckweed-associated bacterial strains, Terrimicrobium sp. PS02 and Aeromicrobium sp. PS05, on the growth, biomass composition, colonization behavior, and transcriptomic responses of Spirodela polyrhiza. While both strains enhanced duckweed biomass, PS02 yielded a 1.2-fold increase, whereas PS05 induced a statistically significant increase (1.4-fold) compared with the uninoculated control. Markedly, PS05 established approximately one order of magnitude higher bacterial populations than PS02 and formed dense extracellular polymeric substance (EPS)-mediated microcolonies on duckweed surfaces. Transcriptome analysis revealed that PS05 induced 1,108 differentially expressed genes, compared with 454 genes for PS02, indicating substantially greater host transcriptomic reprogramming. Functional enrichment analyses demonstrated that PS05 preferentially regulated carbohydrate biosynthesis and central carbon metabolism. Consistently, both transcriptomic and RT-qPCR analyses showed up-regulation of key genes involved in starch biosynthesis and carbon allocation, resulting in significantly enhanced starch accumulation and turion formation without reducing protein or photosynthetic pigment content. This study provides the first integrated evidence linking bacterial colonization strategy, host transcriptomic regulation, carbon allocation, and biomass production in duckweed, thereby establishing a mechanistic basis for engineering high-performance duckweed–microbiome systems for sustainable biomass production.
Project description:Indole is an intercellular and interkingdom signaling molecule, which is widespread in diverse ecological niches. Caenorhabditis elegans is a bacterivorous nematode living in soil and compost environments and a useful model host for the study of host-microbe interactions. While various bacteria and some plants produce a large quantity of extracellular indole, little is known about the effects of indole, its derivatives, and indole-producing bacteria on behaviors in C. elegans and animals. Here, we show that C. elegans senses and moves toward indole and indole-producing bacteria, such as Escherichia coli, Shigella boydii, Providencia stuartii, and Klebsiella oxytoca, while avoids non-indole producing pathogenic bacteria. It was also found that indole-producing bacteria and non-indole-producing bacteria exert divergent effects on egg-laying behavior of C. elegans via indole. In addition, various indole derivatives also modulate chemotaxis, egg-laying behavior, and survival of C. elegans. In contrast, indole at a high concentration to kill C. elegans that has the ability to detoxify indole via oxidation and glucosylation, indicating predator-prey interactions via a double-edged molecule indole. Transcriptional analysis showed that indole markedly up-regulated gene expression of cytochrome P450 family, UDP-glucuronosyltransferase, glutathione S-transferase, which explained well the modification of indole in C. elegans, while down-regulated expression of collagen genes and F-box genes. Our findings suggest that indole and its derivatives are important interkingdom signaling molecules in bacteria-nematode interactions.
2019-08-31 | GSE86312 | GEO
Project description:Triazine-induced extracellular polymeric substance disruption drives metabolic reprogramming and enhanced volatile fatty acid production in sludge anaerobic fermentation
Project description:Anaerobic ammonium oxidizing (anammox) bacteria mediate a key step in the biogeochemical nitrogen cycle and have been applied worldwide for the energy-efficient removal of nitrogen from wastewater. However, outside their core energy metabolism, little is known about the metabolic networks driving anammox bacterial anabolism and mixotrophy beyond genome predictions. Here, we experimentally resolved the central carbon metabolism using metabolomics (LC-MS and GC-MS), metabolic flux analysis and proteomics (shot-gun proteomics).