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Environmental Science & Technology Jun 2024The presence of organic micropollutants in water and sediments motivates investigation of their biotransformation at environmentally low concentrations, usually in the...
The presence of organic micropollutants in water and sediments motivates investigation of their biotransformation at environmentally low concentrations, usually in the range of μg L. Many are biotransformed by cometabolic mechanisms; however, there is scarce information concerning their direct metabolization in this concentration range. Threshold concentrations for microbial assimilation have been reported in both pure and mixed cultures from different origins. The literature suggests a range value for bacterial growth of 1-100 μg L for isolated aerobic heterotrophs in the presence of a single substrate. We aimed to investigate, as a model case, the threshold level for sulfamethoxazole (SMX) metabolization in pure cultures of strain BR1. Previous research with this strain has covered the milligram L range. In this study, acclimated cultures were exposed to concentrations from 0.1 to 25 μg L of C-labeled SMX, and the C-CO produced was trapped and quantified over 24 h. Interestingly, SMX removal was rapid, with 98% removed within 2 h. In contrast, mineralization was slower, with a consistent percentage of 60.0 ± 0.7% found at all concentrations. Mineralization rates increased with rising concentrations. Therefore, this study shows that bacteria are capable of the direct metabolization of organic micropollutants at extremely low concentrations (sub μg L).
Topics: Sulfamethoxazole; Water Pollutants, Chemical
PubMed: 38761139
DOI: 10.1021/acs.est.4c02191 -
Scientific Reports May 2024Spider silk is a promising material with great potential in biomedical applications due to its incredible mechanical properties and resistance to degradation of...
Spider silk is a promising material with great potential in biomedical applications due to its incredible mechanical properties and resistance to degradation of commercially available bacterial strains. However, little is known about the bacterial communities that may inhabit spider webs and how these microorganisms interact with spider silk. In this study, we exposed two exopolysaccharide-secreting bacteria, isolated from webs of an orb spider, to major ampullate (MA) silk from host spiders. The naturally occurring lipid and glycoprotein surface layers of MA silk were experimentally removed to further probe the interaction between bacteria and silk. Extensibility of major ampullate silk produced by Triconephila clavata that was exposed to either Microbacterium sp. or Novosphigobium sp. was significantly higher than that of silk that was not exposed to bacteria (differed by 58.7%). This strain-enhancing effect was not observed when the lipid and glycoprotein surface layers of MA silks were removed. The presence of exopolysaccharides was detected through NMR from MA silks exposed to these two bacteria but not from those without exposure. Here we report for the first time that exopolysaccharide-secreting bacteria inhabiting spider webs can enhance extensibility of host MA silks and silk surface layers play a vital role in mediating such effects.
Topics: Animals; Spiders; Silk; Bacteria; Polysaccharides, Bacterial
PubMed: 38744937
DOI: 10.1038/s41598-024-61723-x -
Animals : An Open Access Journal From... Apr 2024The gut microbiome significantly influences the health and productivity of silkworms (), the cornerstone of sericulture. With the increasing use of cost-effective...
The gut microbiome significantly influences the health and productivity of silkworms (), the cornerstone of sericulture. With the increasing use of cost-effective artificial diets in sericulture, it is crucial to understand how these diets impact the silkworm gut microbiomes. Here we employed 16S rRNA sequencing to delineate the impact of three distinct dietary regimens on the silkworm gut microbiomes: exclusive mulberry leaf diet (SY), exclusive artificial feed diet (SL), and a sequential transition from artificial feed to mulberry leaves (ZS). Our results unveiled stark differences in microbial diversity across the groups, with the ZS group displaying an intermediary complexity. LefSe and random forest analyses identified Methylobacteriaceae, , and as significantly enriched in the ZS group, suggesting their potential to facilitate silkworms' adaptation to dietary transitions. Functional profiling revealed differential pathway regulation, indicating a metabolic reconfiguration in response to dietary modulations. Notably, the enrichment of and in both the SL and ZS groups highlights their potential as probiotics in artificial diets. Our findings provide insights into the diet adaptation mechanisms of silkworm gut microbiota, paving the way for harnessing the intestinal bacteria to enhance silkworm health and silk production through targeted microbial interventions in sericulture practices.
PubMed: 38731265
DOI: 10.3390/ani14091261 -
Microbiology Resource Announcements Jun 2024We characterized the complete genome sequence of phiMiGM15, a lytic bacteriophage with siphovirus morphology that infects . Its 48.6 kb genome contains 81 putative genes...
We characterized the complete genome sequence of phiMiGM15, a lytic bacteriophage with siphovirus morphology that infects . Its 48.6 kb genome contains 81 putative genes and shows coverage of 28% with 82.26% of nucleotide identity to phage Caron accession number OQ190481.1.
PubMed: 38700345
DOI: 10.1128/mra.00302-24 -
Frontiers in Microbiology 2024The plant secondary metabolites (PSMs), as important plant resistance indicators, are important targets for screening plant insect resistance breeding. In this study, we...
BACKGROUND
The plant secondary metabolites (PSMs), as important plant resistance indicators, are important targets for screening plant insect resistance breeding. In this study, we aimed to investigate whether the population of (ZC) is affected by different varieties of PSMs content. At the same time, the structure and function of the gut microbiome of ZC were also analyzed in relation to different pecan varieties.
METHODS
We counted the populations of ZC larvae in four pecan varieties and determined the content of four types of PSMs. The structure and function of the larval gut microbiota were studied in connection to the number of larvae and the content of PSMs. The relationships were investigated between larval number, larval gut microbiota, and PSM content.
RESULTS
We found that the tannins, total phenolics, and total saponins of 4 various pecans PSMs stifled the development of the ZC larval population. The PSMs can significantly affect the diversity and abundance of the larval gut microbiota. Enrichment of ASV46 ( sp.), ASV994 ( sp.), ASV743 ( sp.), ASV709 ( sp.), ASV671 ( sp.), ASV599 ( sp.), ASV575 ( sp.), and ASV27 ( sp.) in the gut of larvae fed on high-resistance cultivars was positively associated with their tannin, total saponin, and total phenolic content. The results of the gut microbiome functional prediction for larvae fed highly resistant pecan varieties showed that the enriched pathways in the gut were related to the breakdown of hazardous chemicals.
CONCLUSION
Our findings provide further evidence that pecan PSMs influence the structure and function of the gut microbiota, which in turn affects the population stability of ZC. The study's findings can serve as a theoretical foundation for further work on selecting ZC-resistant cultivars and developing green management technology for ZC.
PubMed: 38680914
DOI: 10.3389/fmicb.2024.1379488 -
Biology Apr 2024Soil salinization is one of the leading threats to global ecosystems, food security, and crop production. Plant growth-promoting rhizobacteria (PGPRs) are potential...
Soil salinization is one of the leading threats to global ecosystems, food security, and crop production. Plant growth-promoting rhizobacteria (PGPRs) are potential bioinoculants that offer an alternative eco-friendly agricultural approach to enhance crop productivity from salt-deteriorating lands. The current work presents bacterial strain CNUC13 from maize rhizosphere soil that exerted several PGPR traits and abiotic stress tolerance. The strain tolerated up to 1000 mM NaCl and 30% polyethylene glycol (PEG) 6000 and showed plant growth-promoting (PGP) traits, including the production of indole-3-acetic acid (IAA) and siderophore as well as phosphate solubilization. Phylogenetic analysis revealed that strain CNUC13 was . Maize plants exposed to high salinity exhibited osmotic and oxidative stresses, inhibition of seed germination, plant growth, and reduction in photosynthetic pigments. However, maize seedlings inoculated with strain CNUC13 resulted in significantly improved germination rates and seedling growth under the salt-stressed condition. Specifically, compared with the untreated control group, CNUC13-treated seedlings exhibited increased biomass, including fresh weight and root system proliferation. CNUC13 treatment also enhanced photosynthetic pigments (chlorophyll and carotenoids), reduced the accumulation of osmotic (proline) and oxidative (hydrogen peroxide and malondialdehyde) stress indicators, and positively influenced the activities of antioxidant enzymes (catalase, superoxide dismutase, and peroxidase). As a result, CNUC13 treatment alleviated oxidative stress and promoted salt tolerance in maize. Overall, this study demonstrates that CNUC13 significantly enhances the growth of salt-stressed maize seedlings by improving photosynthetic efficiency, osmotic regulators, oxidative stress resilience, and antioxidant enzyme activity. These findings emphasize the potential of utilizing CNUC13 as a bioinoculant to enhance salt stress tolerance in maize, providing an environmentally friendly approach to mitigate the negative effects of salinity and promote sustainable agriculture.
PubMed: 38666856
DOI: 10.3390/biology13040244 -
Biofilm Jun 2024Interspecies interactions within a biofilm community influence population dynamics and community structure, which in turn may affect the bacterial stress response to...
Interspecies interactions within a biofilm community influence population dynamics and community structure, which in turn may affect the bacterial stress response to antimicrobials. This study was conducted to assess the impact of interactions between and a three-species biofilm community (comprising , , and ) on biofilm mass, the abundance of individual species, and their survival under a laboratory-scale cleaning and disinfection (C&D) regime. The presence of enhanced the cell numbers of all three species in pairwise interactions. The outcomes derived from summing up pairwise interactions did not accurately predict the bacterial population dynamics within communities of more than two species. In four-species biofilms, we observed the dominance of and , alongside a concurrent reduction in the cell counts of and . This pattern suggests that the underlying interactions are not purely non-transitive; instead, a more complex interplay results in the dominance of specific species. We observed that bacterial spatial organization and matrix production in different mixed-species combinations affected survival in response to C&D. Confocal microscopy analysis of spatial organization showed that localized on the biofilm formed by and , and was more susceptible to C&D. Matrix production in , evidenced by alterations in biofilm mass and by scanning electron microscopy, demonstrated its protective role against C&D, not only for this species itself, but also for neighbouring species. Our findings emphasise that various social interactions within a biofilm community not only affect bacterial population dynamics but also influence the biofilm community's response to C&D stress.
PubMed: 38639000
DOI: 10.1016/j.bioflm.2024.100195 -
Microbiology Resource Announcements Apr 2024Phage Damascus was isolated from soil in northwestern Wisconsin using as the host. The Damascus genome is 56,477 bp with 3' single-stranded overhangs and 56.5% G+C...
Phage Damascus was isolated from soil in northwestern Wisconsin using as the host. The Damascus genome is 56,477 bp with 3' single-stranded overhangs and 56.5% G+C content. Damascus was assigned to cluster EL and shares 42.6%-91.7% gene content with the three other phages in this cluster.
PubMed: 38624212
DOI: 10.1128/mra.01287-23 -
Microbiology Resource Announcements Apr 2024Nucci, MCubed, and QMacho are microbacteriophages that were isolated from soil samples in Charlotte, NC. They were classified into EA10, EA2, and EB clusters,...
Nucci, MCubed, and QMacho are microbacteriophages that were isolated from soil samples in Charlotte, NC. They were classified into EA10, EA2, and EB clusters, respectively. Nucci and MCubed each had 63 predicted genes, while QMacho had 73 predicted genes.
PubMed: 38597796
DOI: 10.1128/mra.00203-24 -
EFSA Journal. European Food Safety... Apr 2024This assessment addresses a food enzyme preparation consisting of the immobilised non-viable cells of the non-genetically modified bacterium identified by the applicant...
This assessment addresses a food enzyme preparation consisting of the immobilised non-viable cells of the non-genetically modified bacterium identified by the applicant (Samyang Corporation) as strain SYG27B. This strain produces the enzyme D-psicose 3-epimerase (EC 5.1.3.30). The food enzyme preparation is used for the isomerisation of fructose to produce the speciality carbohydrate D-allulose (synonym D-psicose). Since the hazard identification and characterisation could not be made and the identity of the production organism could not be established, the Panel was unable to complete the assessment of this food enzyme preparation containing D-psicose 3-epimerase.
PubMed: 38591024
DOI: 10.2903/j.efsa.2024.8702