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Environmental Science and Ecotechnology Jul 2023The potential release capacity of arsenic (As) from sediment was evaluated under a high level of exogenous organic matter (EOM) with both bioreactive and chemically...
The potential release capacity of arsenic (As) from sediment was evaluated under a high level of exogenous organic matter (EOM) with both bioreactive and chemically reactive organic matters (OMs). The OMs were characterized by FI, HIX, BIX, and SUVA fluorescence indices showing the biological activities were kept at a high level during the experimental period. At the genus level, Fe/Mn/As-reducing bacteria (, , , and ) and bacteria (, , , and ) that can participate in metabolic transformation using EOM were identified. The reducing condition occurs which promoted As, Fe, and Mn releases at very high concentrations of OM. However, As release increased during the first 15-20 days, followed by a decline contributed by secondary iron precipitation. The degree of As release may be limited by the reactivity of Fe (hydro)oxides. The EOM infiltration enhances As and Mn releases in aqueous conditions causing the risk of groundwater pollution, which could occur in specific sites such as landfills, petrochemical sites, and managed aquifer recharge projects.
PubMed: 36896144
DOI: 10.1016/j.ese.2023.100243 -
Frontiers in Cellular and Infection... 2023The present study aims to investigate the effect of (Hp) infection on gastric mucosal microbiota in patients with chronic gastritis.
OBJECTIVE
The present study aims to investigate the effect of (Hp) infection on gastric mucosal microbiota in patients with chronic gastritis.
METHODS
Here recruited a population of 193 patients with both chronic gastritis and positive rapid urease, including 124 patients with chronic atrophic gastritis (CAG) and 69 patients with chronic non-atrophic gastritis (nCAG). Immunoblotting was used to detect four serum Hp antibodies (UreA, UreB, VacA and CagA) to determine the types of virulent Hp-I and avirulent Hp-II infections. Gastric microbiota was profiled by 16S rRNA gene V3-V4 region, and R software was used to present the relationship between the microbial characteristics and the type of Hp infection.
RESULTS
In the stomach of patients with Hp-positive gastritis, the dominant gastric bacterial genera included (23.94%), (20.28%), (9.99%), (9.21%), (5.05%), and (4.75%). The proportion of Hp-I infection was significantly higher in CAG patients (91.1%) than in nCAG patients (71.0%) ( < 0.001). The gastric microbiota richness index (observed OTUs, Chao) was significantly lower in CAG patients than in nCAG patients (0.05). Compared with avirulent Hp-II infection, virulent Hp-I infection significantly decreased the Shannon index in CAG patients (0.05). In nCAG patients, Hp-I infected patients had lower abundances of several dominant gastric bacteria (, , , , ) than Hp-II infected patients. Meanwhile, in CAG patients, Hp-I infected patients occupied lower abundances of several dominant oral bacteria (, and ) than Hp-II infected patients. In addition, bile reflux significantly promoted the colonization of dominant oral microbiota (, and ) in the stomach of CAG patients. There was no significant symbiotic relationship between bacteria and non- bacteria in the stomach of nCAG patients, while bacteria distinctly linked with the non- bacteria (, , , and ) in CAG patients.
CONCLUSIONS
Virulent Hp infection alters the gastric microbiota, reduces microbial diversity, and enhances the symbiotic relationship between the bacteria and non- bacteria in patients with chronic gastritis. The data provides new evidence for treating Hp infection by improving the gastric microbiota.
Topics: Humans; Helicobacter pylori; Helicobacter Infections; RNA, Ribosomal, 16S; Gastritis
PubMed: 37662018
DOI: 10.3389/fcimb.2023.1221433 -
MBio Aug 2023is a gram-negative plant pathogen that employs the type Ⅲ secretion system (T3SS) to infect cucurbit crops and cause bacterial fruit blotch. This bacterium also...
is a gram-negative plant pathogen that employs the type Ⅲ secretion system (T3SS) to infect cucurbit crops and cause bacterial fruit blotch. This bacterium also possesses an active type Ⅵ secretion system (T6SS) with strong antibacterial and antifungal activities. However, how plant cells respond to these two secretion systems and whether there is any cross talk between T3SS and T6SS during infection remain unknown. Here, we employ transcriptomic analysis to compare cellular responses to the T3SS and the T6SS during infection and report distinctive effects on multiple pathways. The T3SS-mediated differentially expressed genes were enriched in the pathways of phenylpropanoid biosynthesis, plant-pathogen interaction, MAPK signaling pathway, and glutathione metabolism, while the T6SS uniquely affected genes were related to photosynthesis. The T6SS does not contribute to the virulence of but is critical for the survival of the bacterium when mixed with watermelon phyllosphere bacteria. In addition, T3SS-mediated virulence is independent of the T6SS, and the inactivation of the T3SS does not affect the T6SS-mediated competition against a diverse set of bacterial pathogens that commonly contaminate edible plants or directly infect plants. A T6SS-active T3SS-null mutant (Ac) could inhibit the growth of pv. significantly both and and also reduce symptoms of rice bacterial blight. In conclusion, our data demonstrate the T6SS in is nonpathogenic to the plant host and can be harnessed as a pathogen killer against plant-associated bacteria. IMPORTANCE Chemical pesticides are widely used to protect crops from various pathogens. Still, their extensive use has led to severe consequences, including drug resistance and environmental contamination. Here, we show that an engineered T6SS-active, but avirulent mutant of has strong inhibition capabilities against several pathogenic bacteria, demonstrating an effective strategy that is an alternative to chemical pesticides for sustainable agricultural practices.
Topics: Plant Cells; Citrullus; Fruit; Pesticides; Plant Diseases
PubMed: 37288971
DOI: 10.1128/mbio.00459-23 -
Environment International Aug 2023Antimony (Sb) is toxic to ecosystems and potentially to public health via its accumulation in the food chain. Bioavailability and toxicity of Sb have been reduced using...
Antimony (Sb) is toxic to ecosystems and potentially to public health via its accumulation in the food chain. Bioavailability and toxicity of Sb have been reduced using various methods for the remediation of Sb-contaminated soil in most studies. However, Sb-contaminated soil remediation by microbial agents has been rarely evaluated. In this study, we evaluated the potential for the use of Comamonas testosteroni JL40 in the bioremediation of Sb-contamination. Strain JL40 immobilized more than 30 % of the Sb(III) in solution and oxidized over 18 % to Sb(V) for detoxification. Meanwhile, strain JL40 responds to Sb toxicity through such as Sb efflux, intracellular accumulation, biofilm production, and scavenging of reactive oxygen species (ROS), etc. The results of the pot experiment showed the average Sb content of the brown rice was decreased by 59.1%, 38.8%, and 48.4%, for 1.8, 50, and 100 mg/kg Sb spiked soils, respectively. In addition, the results of plant, soil enzyme activity, and rice agronomic trait observations showed that the application of strain JL40 could maintain the health of plants and soil and improve rice production. The single-step and sequential extraction of Sb from rhizosphere soil showed that strain JL40 also plays a role in Sb immobilization and oxidation in the soil environment. During rice potted cultivation, bacterial community analysis and plate counting showed that the strain JL40 could still maintain 10 CFU/g after 30 days of inoculation. With phenotypic and differential proteomics analysis, strain JL40 conferred Sb(III) tolerance by a combination of immobilization, oxidation, efflux and scavenging of ROS, etc. Our study demonstrates the application of Sb-immobilizing and oxidizing bacteria to lower soil Sb and reduce accumulation of Sb in rice. Our results provide guidance for bacterial remediation of Sb-contaminated soil.
Topics: Soil; Antimony; Comamonas testosteroni; Biodegradation, Environmental; Ecosystem; Reactive Oxygen Species; Soil Pollutants
PubMed: 37356310
DOI: 10.1016/j.envint.2023.108040 -
International Journal of Molecular... Oct 2023Non-alcoholic fatty liver disease (NAFLD) is considered the most common chronic liver disease worldwide, affecting nearly 25% of the global adult population. Increasing...
Non-alcoholic fatty liver disease (NAFLD) is considered the most common chronic liver disease worldwide, affecting nearly 25% of the global adult population. Increasing evidence suggests that functional and compositional changes in the gut microbiota may contribute to the development and promote the progression of NAFLD. 16S rRNA gene next-generation sequencing is widely used to determine specific features of the NAFLD microbiome, but a complex system such as the gut microbiota requires a comprehensive approach. We used three different approaches: MALDI-TOF-MS of bacterial cultures, qPCR, and 16S NGS sequencing, as well as a wide variety of statistical methods to assess the differences in gut microbiota composition between NAFLD patients without significant fibrosis and the control group. The listed methods showed enrichment in sp. and for the control samples and enrichment in (and in particular sp.) and in NAFLD. The families, , , and (particularly and ), were also found to be important taxa for NAFLD microbiome evaluation. Considering individual method observations, an increase in and a decrease in for NAFLD patients were detected using MALDI-TOF-MS. An increase in , , , , , and , and a decrease in in NAFLD were observed with 16S NGS, and enrichment in was shown using qPCR analysis. These findings confirm that NAFLD is associated with changes in gut microbiota composition. Further investigations are required to determine the cause-and-effect relationships and the impact of microbiota-derived compounds on the development and progression of NAFLD.
Topics: Adult; Humans; Non-alcoholic Fatty Liver Disease; Gastrointestinal Microbiome; RNA, Ribosomal, 16S; Fibrosis; Microbiota; Bacteroidetes; Liver
PubMed: 37894951
DOI: 10.3390/ijms242015272 -
Plants (Basel, Switzerland) Aug 2023Bacterial panicle blight, bacterial leaf streak, and bacterial brown stripe are common bacterial diseases in rice that represent global threats to stable rice yields. In...
Bacterial panicle blight, bacterial leaf streak, and bacterial brown stripe are common bacterial diseases in rice that represent global threats to stable rice yields. In this study, we used the rice variety HZ, Nekken and their 120 RIL population as experimental materials. Phenotypes of the parents and RILs were quantitatively analyzed after inoculation with , pv. , and subsp. . Genetic SNP maps were also constructed and used for QTL mapping of the quantitative traits. We located 40 QTL loci on 12 chromosomes. The analysis of disease resistance-related candidate genes in the QTL regions with high LOD value on chromosomes 1, 3, 4, and 12 revealed differential expression before and after treatment, suggesting that the identified genes mediated the variable disease resistance profiles of Huazhan and Nekken2. These results provide an important foundation for cloning bacterial-resistant QTLs of panicle blight, leaf streak, and brown stripe in rice.
PubMed: 37571006
DOI: 10.3390/plants12152853 -
PloS One 2023As a strategy for minimizing microbial infections in fish hatcheries, we have investigated how putatively probiotic bacterial populations influence biofilm formation....
As a strategy for minimizing microbial infections in fish hatcheries, we have investigated how putatively probiotic bacterial populations influence biofilm formation. All surfaces that are exposed to the aquatic milieu develop a microbial community through the selective assembly of microbial populations into a surface-adhering biofilm. In the investigations reported herein, we describe laboratory experiments designed to determine how initial colonization of a surface by nonpathogenic isolates from sturgeon eggs influence the subsequent assembly of populations from a pelagic river community, into the existing biofilm. All eight of the tested strains altered the assembly of river biofilm in a strain-specific manner. Previously formed isolate biofilm was challenged with natural river populations and after 24 hours, two strains and two-isolate combinations proved highly resistant to invasion, comprising at least 80% of the biofilm community, four isolates were intermediate in resistance, accounting for at least 45% of the biofilm community and two isolates were reduced to 4% of the biofilm community. Founding biofilms of Serratia sp, and combinations of Brevundimonas sp.-Hydrogenophaga sp. and Brevundimonas sp.-Acidovorax sp. specifically blocked populations of Aeromonas and Flavobacterium, potential fish pathogens, from colonizing the biofilm. In addition, all isolate biofilms were effective at blocking invading populations of Arcobacter. Several strains, notably Deinococcus sp., recruited specific low-abundance river populations into the top 25 most abundant populations within biofilm. The experiments suggest that relatively simple measures can be used to control the assembly of biofilm on the eggs surface and perhaps offer protection from pathogens. In addition, the methodology provides a relatively rapid way to detect potentially strong ecological interactions between bacterial populations in the formation of biofilms.
Topics: Animals; Rivers; Biofilms; Flavobacterium; Bacteria, Aerobic; Fishes
PubMed: 37956125
DOI: 10.1371/journal.pone.0288040 -
PeerJ 2023Solid-phase denitrification shows promise for removing nitrate (NO-N) from water. Biological denitrification uses external carbon sources to remove nitrogen from...
Solid-phase denitrification shows promise for removing nitrate (NO-N) from water. Biological denitrification uses external carbon sources to remove nitrogen from wastewater, among which agriculture waste is considered the most promising source due to its economic and efficiency advantages. Hydraulic retention time (HRT) and influent nitrate concentration (INC) are the main factors influencing biological denitrification. This study explored the effects of HRT and INC on solid-phase denitrification using wheat husk (WH) as a carbon source. A solid-phase denitrification system with WH carbon source was constructed to explore denitrification performance with differing HRT and INC. The optimal HRT and INC of the wheat husk-denitrification reactor (WH-DR) were 32 h and 50 mg/L, respectively. Under these conditions, NO-N and total nitrogen removal rates were 97.37 ± 2.68% and 94.08 ± 4.01%, respectively. High-throughput sequencing revealed that the dominant phyla in the WH-DR operation were Proteobacteria, Bacteroidetes, and Campilobacterota. Among the dominant genera, (0.85%), (0.38%), (4.22%), and (0.60%) have denitrification functions; (0.47%) is mainly involved in the degradation of WH; and (0.37%) and (0.86%) can both denitrify and degrade WH. This study determined the optimal HRT and INC for WH-DR and provides a reference for the development and application of WH as a novel, slow-release carbon source in treating aquaculture wastewater.
Topics: Wastewater; Nitrates; Denitrification; Triticum; Carbon; Bioreactors; Comamonadaceae; Nitrogen
PubMed: 37520256
DOI: 10.7717/peerj.15756 -
Molecular Plant-microbe Interactions :... Oct 2023In recent years subsp. was identified as a major cause of bacterial etiolation and decline (BED) in turfgrasses and has become a growing economical concern for the...
In recent years subsp. was identified as a major cause of bacterial etiolation and decline (BED) in turfgrasses and has become a growing economical concern for the turfgrass industry. The symptoms of BED resemble those of "bakanae," or foolish seedling disease, of rice (), in which the gibberellins produced by the infecting fungus, , contribute to the symptom development. Additionally, an operon coding for the enzymes necessary for bacterial gibberellin production was recently characterized in plant-pathogenic bacteria belonging to the γ-proteobacteria. We therefore investigated whether this gibberellin operon might be present in subsp. . A homolog of the operon has been identified in two turfgrass-infecting subsp. phylogenetic groups but not in closely related phylogenetic groups or strains infecting other plants. Moreover, even within these two phylogenetic groups, the operon presence is not uniform. For that reason, the functionality of the operon was examined in one strain of each turfgrass-infecting phylogenetic group ( subsp. strains KL3 and MD5). All nine operon genes were functionally characterized through heterologous expression in and enzymatic activities were analyzed by liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry. All enzymes were functional in both investigated strains, thus demonstrating the ability of phytopathogenic β-proteobacteria to produce biologically active GA. This additional gibberellin produced by subsp. could disrupt phytohormonal balance and be a leading factor contributing to the pathogenicity on turf grasses. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Topics: Gibberellins; Phylogeny; Poaceae; Comamonadaceae; Plants
PubMed: 37227226
DOI: 10.1094/MPMI-02-23-0017-R -
Frontiers in Microbiology 2023Coumarin-3-carboxylic acid (3-CCA), previously screened from natural coumarins, was found to possess strong antibacterial activity against (). In order to further...
Coumarin-3-carboxylic acid (3-CCA), previously screened from natural coumarins, was found to possess strong antibacterial activity against (). In order to further evaluate the activity of this compound against plant bacterial pathogens and explore its potential value as a bactericidal lead compound, the activity of 3-CCA against 14 plant pathogenic bacteria and was tested. Results showed that 3-CCA exhibited strong activities against pv. pv. , and with EC values ranging from 26.64 μg/mL to 40.73 μg/mL. showed that 3-CCA had powerful protective and curative effects against . In addition, the protective efficiency of 3-CCA was almost equivalent to that of thiodiazole copper at the same concentration. The results of SEM and TEM observation and conductivity tests showed that 3-CCA disrupted the integrity of the cell membrane and inhibited polar flagella growth. Furthermore, 3-CCA resulted in reductions in motility and extracellular exopolysaccharide (EPS) production of while inhibiting the biofilm formation of . These findings indicate that 3-CCA could be a promising natural lead compound against plant bacterial pathogens to explore novel antibacterial agents.
PubMed: 37799610
DOI: 10.3389/fmicb.2023.1207125