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Inorganic Chemistry Oct 2023Two hybrid-type artificial siderophore ligands containing both catecholate and hydroxamate groups as iron-capturing sites,...
Two hybrid-type artificial siderophore ligands containing both catecholate and hydroxamate groups as iron-capturing sites, bis(2,3-dihydroxybenzamidepropyl)mono[2-propyl]aminomethane () and mono(2,3-dihydroxybenzamide-propyl)bis[2-propyl]aminomethane (, were designed and synthesized. Iron(III) complexes, K[] and K[], were prepared and characterized spectroscopically, potentiometrically, and electrochemically. The results were compared with those previously reported for iron complexes with non-hybridized siderophores containing either catecholate or hydroxamate groups, K[] and []. Both K[] and K[] formed six-coordinate octahedral iron(III) complexes. Evaluation of the thermodynamic properties of the complexes in an aqueous solution indicated high log β values of 37.3 and 32.3 for K[] and K[], respectively, which were intermediate between those of K[] (44.2) and [] (31). Evaluation of the ultraviolet-visible and Fourier transform infrared spectra of the two hybrid siderophore-iron complexes under different pH or pD (potential of dueterium) conditions showed that the protonation of K[] and K[] generated the corresponding protonated species, [] and [], accompanied by a significant change in the coordination mode. The protonated hybrid-type siderophore-iron complexes showed high reduction potentials, which were well within the range of those of biological reductants. The results suggest that the hybrid-type siderophore easily releases an iron(III) ion at low pH. The biological activity of the four artificial siderophore-iron complexes against and clearly depends on the structural differences between the complexes. This finding demonstrates that the changes in the coordination sites of the siderophores enable close control of the interactions between the siderophores and receptors in the cell membrane.
PubMed: 37738382
DOI: 10.1021/acs.inorgchem.3c01786 -
Microbiological Research Aug 2023Increasing industrialization and anthropogenic activities have resulted in the release of a wide variety of pollutants into the environment including pesticides,... (Review)
Review
Increasing industrialization and anthropogenic activities have resulted in the release of a wide variety of pollutants into the environment including pesticides, polycyclic aromatic hydrocarbons (PAHs), and heavy metals. These pollutants pose a serious threat to human health as well as to the ecosystem. Thus, the removal of these compounds from the environment is highly important. Mitigation of the environmental pollution caused by these pollutants via bioremediation has become a promising approach nowadays. Actinobacteria are a group of eubacteria mostly known for their ability to produce secondary metabolites. The morphological features such as spore formation, filamentous growth, higher surface area to volume ratio, and cellular mechanisms like EPS secretion, and siderophore production in Actinobacteria render higher resistance and biodegradation ability. In addition, these bacteria possess several oxidoreductase systems (oxyR, catR, furA, etc.) which help in bioremediation. Actinobacteria genera including Arthrobacter, Rhodococcus, Streptomyces, Nocardia, Microbacterium, etc. have shown great potential for the bioremediation of various pollutants. In this review, the bioremediation ability of these bacteria has been discussed in detail. The utilization of various genera of Actinobacteria for the biodegradation of organic pollutants, including pesticides and PAHs, and inorganic pollutants like heavy metals has been described. In addition, the cellular mechanisms in these microbes which help to withstand oxidative stress have been discussed. Finally, this review explores the Actinobacteria mediated strategies and recent technologies such as the utilization of mixed cultures, cell immobilization, plant-microbe interaction, utilization of biosurfactants and nanoparticles, etc., to enhance the bioremediation of various environmental pollutants.
Topics: Humans; Environmental Pollutants; Biodegradation, Environmental; Actinobacteria; Ecosystem; Polycyclic Aromatic Hydrocarbons; Arthrobacter; Metals, Heavy; Pesticides; Soil Pollutants
PubMed: 37150049
DOI: 10.1016/j.micres.2023.127399 -
Environmental Science and Pollution... Oct 2023Management of tailings at metal mine smelter sites can reduce the potential hazards associated with exposure to toxic metal(loid)s and residual organic flotation...
Management of tailings at metal mine smelter sites can reduce the potential hazards associated with exposure to toxic metal(loid)s and residual organic flotation reagents. In addition, microbes in the tailings harboring multi-resistance genes (e.g., tolerance to multiple antimicrobial agents) can cause high rates of morbidity and global economic problems. The potential co-selection mechanisms of antibiotic resistance genes (ARGs) and metal(loid) resistance genes (MRGs) during tailings sulfate-reducing bacteria (SRB) treatment have been poorly investigated. Samples were collected from a nonferrous metal mine tailing site treated with an established SRB protocol and were analyzed for selected geochemical properties and high throughput sequencing of 16S rRNA gene barcoding. Based on the shotgun metagenomic analysis, the bacterial domain was dominant in nonferrous metal(loid)-rich tailings treated with SRB for 12 months. KEGGs related to ARGs and MRGs were detected. Thiobacillus and Sphingomonas were the main genera carrying the bacA and mexEF resistance operons, along with Sulfuricella which were also found as the main genera carrying MRGs. The SRB treatment may mediate the distribution of numerous resistance genes. KOs based on the metagenomic database indicated that ARGs (mexNW, merD, sul, and bla) and MRGs (czcABCR and copRS genes) were found on the same contig. The SRB strains (Desulfosporosinus and Desulfotomaculum), and the acidophilic strain Acidiphilium significantly contributed to the distribution of sul genes. The functional metabolic pathways related to siderophores metabolism were largely from anaerobic genera of Streptomyces and Microbacterium. The presence of arsenate reductase, metal efflux pump, and Fe transport genes indicated that SRB treatment plays a key role in the metal(loid)s transformation. Overall, our findings show that bio-treatment is an effective tool for managing ARGs/MRGs and metals in tailings that contain numerous metal(loid) contaminants.
Topics: RNA, Ribosomal, 16S; Metals; Bacteria; Anti-Bacterial Agents; China; Sulfates; Genes, Bacterial
PubMed: 37707732
DOI: 10.1007/s11356-023-29203-3 -
Archives of Microbiology Apr 2024
PubMed: 38573539
DOI: 10.1007/s00203-024-03929-1 -
Journal of Hazardous Materials Jul 2023In the study, a novel ENR-degrading microorganism, Microbacterium proteolyticum GJEE142 was isolated from aquaculture wastewater for the first time. The ENR removal of...
Characterization and removal mechanism of a novel enrofloxacin-degrading microorganism, Microbacterium proteolyticum GJEE142 capable of simultaneous removal of enrofloxacin, nitrogen and phosphorus.
In the study, a novel ENR-degrading microorganism, Microbacterium proteolyticum GJEE142 was isolated from aquaculture wastewater for the first time. The ENR removal of strain GJEE142 was reliant upon the provision of limited additional carbon source, and was adaptative to low temperature (13 ℃) and high salinity (50‰). The ENR removal process, to which intracellular enzymes made more contributions, was implemented in three proposed pathways. During the removal process, oxidative stress response of strain GJEE142 was activated and the bacterial toxicity of ENR was decreased. Strain GJEE142 could also achieve the synchronous removal of ammonium, nitrite, nitrate and phosphorus with the nitrogen removal pathways of nitrate → nitrite → ammonium → glutamine → glutamate → glutamate metabolism and nitrate → nitrite → gaseous nitrogen. The phosphorus removal was implemented under complete aerobic conditions with the assistance of polyphosphate kinase and exopolyphosphatase. Genomic analysis provided corresponding genetic insights for deciphering removal mechanisms of ENR, nitrogen and phosphorus. ENR, nitrogen and phosphorus in both actual aquaculture wastewater and domestic wastewater could be desirably removed. Desirable adaptation, excellent performance and wide distribution will make strain GJEE142 the hopeful strain in wastewater treatment.
Topics: Wastewater; Phosphorus; Nitrites; Nitrates; Denitrification; Enrofloxacin; Nitrogen; Ammonium Compounds; Bioreactors; Nitrification
PubMed: 37104955
DOI: 10.1016/j.jhazmat.2023.131452 -
IScience Jun 2024remains one of the deadliest infectious agents globally. Amidst efforts to control TB, long treatment duration, drug toxicity, and resistance underscore the need for...
remains one of the deadliest infectious agents globally. Amidst efforts to control TB, long treatment duration, drug toxicity, and resistance underscore the need for novel therapeutic strategies. Despite advances in understanding the interplay between microbiome and disease in humans, the specific role of the microbiome in predicting disease susceptibility and discriminating infection status in tuberculosis still needs to be fully investigated. We investigated the impact of infection and -specific IFNγ immune responses on airway microbiome diversity by performing TB GeneXpert and QuantiFERON-GOLD assays during the follow-up phase of a longitudinal HIV-Lung Microbiome cohort of individuals recruited from two large independent cohorts in rural Uganda. rather than IFNγ immune response mainly drove a significant reduction in airway microbiome diversity. A microbiome signature comprising , , , and accurately discriminated active TB from Latent TB and uninfected individuals.
PubMed: 38904070
DOI: 10.1016/j.isci.2024.110142 -
Microbiome Oct 2023Shrimp cultured in a biofloc system (BFS) have a lower disease incidence than those farmed in a water exchange system (WES). Although a number of studies have reported...
BACKGROUND
Shrimp cultured in a biofloc system (BFS) have a lower disease incidence than those farmed in a water exchange system (WES). Although a number of studies have reported that the gut bacterial community induced by BFS is highly associated with shrimp disease resistance, the causal relationship remains unknown. Here, the promotive roles of gut bacterial community induced by BFS in pathogenic Vibrio infection resistance and its potential micro-ecological and physiological mechanisms were investigated by gut bacterial consortium transplantation and synthetic community (SynCom) construction.
RESULTS
The BFS induced a more stable and resistant gut bacterial community, and significantly enriched some beneficial bacterial taxa, such as Paracoccus, Ruegeria, Microbacterium, Demequina, and Tenacibaculum. Transplantation of a gut bacterial consortium from BFS shrimp (Enrich) greatly enhanced the stability of the bacterial community and resistance against pathogenic V. parahaemolyticus infection in WES shrimp, while transplantation of a gut bacterial consortium from WES shrimp significantly disrupted the bacterial community and increased pathogen susceptibility in both WES and BFS shrimp. The addition of Enrich in shrimp postlarvae also improved the pathogen resistance through increasing the relative abundances of beneficial bacterial taxa and stability of bacterial community. The corresponding strains of five beneficial bacterial taxa enriched in BFS shrimp were isolated to construct a SynCom. The addition of SynCom could not only suppress disease development, but also improve shrimp growth, boost the digestive and immune activities, and restore health in diseased shrimp. Furthermore, the strains of SynCom well colonized shrimp gut to maintain a high stability of bacterial community.
CONCLUSIONS
Our study reveals an important role for native microbiota in protecting shrimp from bacterial pathogens and provides a micro-ecological regulation strategy towards the development of probiotics to ameliorate aquatic animal diseases. Video Abstract.
Topics: Animals; Vibrio parahaemolyticus; Gastrointestinal Microbiome; Penaeidae; Bacteria; Vibrio Infections; Aquaculture
PubMed: 37858205
DOI: 10.1186/s40168-023-01663-2 -
Animal Microbiome Nov 2023The goal of this study was to assess the microbial ecology and diversity present in the uterus of post-partum dairy cows with and without metritis from 24 commercial...
BACKGROUND
The goal of this study was to assess the microbial ecology and diversity present in the uterus of post-partum dairy cows with and without metritis from 24 commercial California dairy farms using shotgun metagenomics. A set subset of 95 intrauterine swab samples, taken from a larger selection of 307 individual cow samples previously collected, were examined for α and β diversity and differential abundance associated with metritis. Cows within 21 days post-partum were categorized into one of three clinical groups during sample collection: control (CT, n = 32), defined as cows with either no vaginal discharge or a clear, non-purulent mucus vaginal discharge; metritis (MET, n = 33), defined as a cow with watery, red or brown colored, and fetid vaginal discharge; and purulent discharge cows (PUS, n = 31), defined as a non-fetid purulent or mucopurulent vaginal discharge.
RESULTS
All three clinical groups (CT, MET, and PUS) were highly diverse, with the top 12 most abundant genera accounting for 10.3%, 8.8%, and 10.1% of mean relative abundance, respectively. The α diversity indices revealed a lower diversity from samples collected from MET and PUS when compared to CT cows. PERMANOVA statistical testing revealed a significant difference (P adjusted < 0.01) in the diversity of genera between CT and MET samples (R2 = 0.112, P = 0.003) and a non-significant difference between MET and PUS samples (R2 = 0.036, P = 0.046). ANCOM-BC analysis revealed that from the top 12 most abundant genera, seven genera were increased in the natural log fold change (LFC) of abundance in MET when compared to CT samples: Bacteroides, Clostridium, Fusobacterium, Phocaeicola, Porphyromonas, Prevotella, and Streptococcus. Two genera, Dietzia and Microbacterium, were decreased in natural LFC of abundance when comparing MET (regardless of treatment) and CT, while no changes in natural LFC of abundance were observed for Escherichia, Histophilus, and Trueperella.
CONCLUSIONS
The results presented here, are the current deepest shotgun metagenomic analyses conducted on the bovine uterine microbiome to date (mean of 256,425 genus-level reads per sample). Our findings support that uterine samples from cows without metritis (CT) had increased α-diversity but decreased β-diversity when compared to metritis or PUS cows, characteristic of dysbiosis. In summary, our findings highlight that MET cows have an increased abundance of Bacteroides, Porphyromonas, and Fusobacterium when compared to CT and PUS, and support the need for further studies to better understand their potential causal role in metritis pathogenesis.
PubMed: 37986012
DOI: 10.1186/s42523-023-00281-5 -
Frontiers in Plant Science 2023Grazing disturbance can change the structure of plant rhizosphere microbial communities and thereby alter the feedback to promote plant growth or induce plant defenses....
Grazing disturbance can change the structure of plant rhizosphere microbial communities and thereby alter the feedback to promote plant growth or induce plant defenses. However, little is known about how such changes occur and vary under different grazing pressures or the roles of root metabolites in altering the composition of rhizosphere microbial communities. In this study, the effects of different grazing pressures on the composition of microbial communities were investigated, and the mechanisms by which different grazing pressures changed rhizosphere microbiomes were explored with metabolomics. Grazing changed composition, functions, and co-expression networks of microbial communities. Under light grazing (LG), some saprophytic fungi, such as sp., sp., sp. and sp., were significantly enriched, whereas under heavy grazing (HG), potentially beneficial rhizobacteria, such as sp., sp., and sp., were significantly enriched. The beneficial mycorrhizal fungus sp. was significantly enriched in both LG and HG. Moreover, all enriched beneficial microorganisms were positively correlated with root metabolites, including amino acids (AAs), short-chain organic acids (SCOAs), and alkaloids. This suggests that these significantly enriched rhizosphere microbial changes may be caused by these differential root metabolites. Under LG, it is inferred that root metabolites, especially AAs such as L-Histidine, may regulate specific saprophytic fungi to participate in material transformations and the energy cycle and promote plant growth. Furthermore, to help alleviate the stress of HG and improve plant defenses, it is inferred that the root system actively regulates the synthesis of these root metabolites such as AAs, SCOAs, and alkaloids under grazing interference, and then secretes them to promote the growth of some specific plant growth-promoting rhizobacteria and fungi. To summarize, grasses can regulate beneficial microorganisms by changing root metabolites composition, and the response strategies vary under different grazing pressure in typical grassland ecosystems.
PubMed: 37484473
DOI: 10.3389/fpls.2023.1180576 -
Frontiers in Medicine 2023Peritoneal dialysis-related peritonitis (PDRP) caused by . is very rare, with only 9 cases reported to date. In this study, we report the treatment experiences of 7...
INTRODUCTION
Peritoneal dialysis-related peritonitis (PDRP) caused by . is very rare, with only 9 cases reported to date. In this study, we report the treatment experiences of 7 patients at our peritoneal dialysis center.
METHODS
We retrospectively collected clinical characteristics and antibiotic management of all 7 episodes of PDRP caused by . in 7 patients from at our center over 4 years, and reviewed the documented . PDRP in the literature.
RESULTS
Empiric antibiotic therapy was initiated as soon as possible, and consisted of intraperitoneal (IP) gentamicin in combination with vancomycin. After up to 5 days, gentamicin was changed to meropenem if the treatment was not effective. The intended course of antibiotic treatment was 21-day. Totally, 6 episodes were cured (85.7%), which was higher than reported.
CONCLUSION
The 21-day antibiotic therapy program by combining vancomycin and meropenem may benefit the management of . PDRP.
PubMed: 38076234
DOI: 10.3389/fmed.2023.1297296