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Journal of Hazardous Materials Jun 2024Deep geological repositories (DGRs) stand out as one of the optimal options for managing high-level radioactive waste (HLW) such as uranium (U) in the near future. Here,...
Deep geological repositories (DGRs) stand out as one of the optimal options for managing high-level radioactive waste (HLW) such as uranium (U) in the near future. Here, we provide novel insights into microbial behavior in the DGR bentonite barrier, addressing potential worst-case scenarios such as waste leakage (e.g., U) and groundwater infiltration of electron rich donors in the bentonite. After a three-year anaerobic incubation, Illumina sequencing results revealed a bacterial diversity dominated by anaerobic and spore-forming microorganisms mainly from the phylum Firmicutes. Highly U tolerant and viable bacterial isolates from the genera Peribacillus, Bacillus, and some SRB such as Desulfovibrio and Desulfosporosinus, were enriched from U-amended bentonite. The results obtained by XPS and XRD showed that U was present as U(VI) and as U(IV) species. Regarding U(VI), we have identified biogenic U(VI) phosphates, U(UO)·(PO) located in the inner part of the bacterial cell membranes in addition to U(VI)-adsorbed to clays such as montmorillonite. Biogenic U(IV) species as uraninite may be produced as result of bacterial enzymatic U(VI) reduction. These findings suggest that under electron donor-rich water-saturation conditions, bentonite microbial community can control U speciation, immobilizing it, and thus enhancing future DGR safety if container rupture and waste leakage occurs.
PubMed: 38943881
DOI: 10.1016/j.jhazmat.2024.135044 -
Journal of Environmental Management Jun 2024Low methane production and long retention time are the main dilemmas in current anaerobic digestion (AD) of waste activated sludge (WAS). This work used WAS as only...
Development of oriented multi-enzyme strengthens waste activated sludge disintegration and anaerobic digestion: Performance, components transformation and microbial communities.
Low methane production and long retention time are the main dilemmas in current anaerobic digestion (AD) of waste activated sludge (WAS). This work used WAS as only substrate to prepare oriented multi-enzyme (ME) that directly used for WAS pretreatment. Under the optimal parameters, the highest activities of protease and amylase in ME could respectively reach 16.5 U/g and 580 U/g, and the corresponding methane production attained 197 mLCH/g VS, which was increased by 70.4% compared to blank group. It was found that ME pretreatment could strengthen WAS disintegration and organic matters dissolution, lead to the soluble chemical oxygen demand (SCOD) was increased from the initial 486 mg/L to 2583 mg/L, and the corresponding volatile suspended solid (VSS) and extracellular polymeric substances (EPS) were reduced by 27% and 73.8%, respectively. The results of three-dimensional excitation-emission matrix (3D-EEM) and Fourier transform infrared spectroscopy (FTIR) indicated that protein disintegration may be the critical step during the process of WAS hydrolysis with ME, of which the release of tyrosine-like proteins achieved the better biodegradability of WAS, while the results of X-ray photoelectron spectroscopy (XPS) showed that the formation of protein derivatives was the main harmful factor that could extend the lag phase of AD process. Microbial communities analysis further suggested that ME pretreatment facilitated the enrichment of acetogenic bacteria and acetotrophic methanogens, which caused the transition of the methanogenesis pathway from hydrogenotrophic to acetotrophic. This study is expected to furnish valuable insight for ME pretreatment on enhancing WAS disintegration and methane production.
PubMed: 38943750
DOI: 10.1016/j.jenvman.2024.121614 -
Advanced Materials (Deerfield Beach,... Jun 2024The disorder of the macrophage phenotype and the hostile by-product of lactate evoked by pathogenic infection in hypoxic deep wound inevitably lead to the stagnant skin...
The disorder of the macrophage phenotype and the hostile by-product of lactate evoked by pathogenic infection in hypoxic deep wound inevitably lead to the stagnant skin regeneration. In this study, we developed HS-evolving alternately catalytic bio-heterojunction enzyme (AC-BioHJzyme) consisting of CuFeS and lactate oxidase (CuFeS@LOD). AC-BioHJzyme exhibits circular enzyme-mimetic antibacterial (EMA) activity and macrophage re-rousing capability, which can be activated by near-infrared-II (NIR-II) light. In this system, LOD exhausts lactate derived from bacterial anaerobic respiration and generated hydrogen peroxide (HO), which provides an abundant stock for the peroxidase-mimetic activity to convert the produced HO into germicidal •OH. The GPx-mimetic activity endows AC-BioHJzyme with a glutathione consumption property to block the antioxidant systems in bacterial metabolism, while the O provided by the CAT-mimetic activity can generate O under the NIR-II irradiation. Synchronously, the HS gas liberated from CuFeS@LOD under the infectious micromilieu allows the reduction of Fe(III)/Cu(II) to Fe(II)/Cu(І), resulting in sustained circular EMA activity. In vitro and in vivo assays indicate that the CuFeS@LOD AC-BioHJzyme significantly facilitates the infectious cutaneous regeneration by killing bacteria, facilitating epithelialization/collagen deposition, promoting angiogenesis and reprogramming macrophages. This study provides a countermeasure for deep infectious wound healing via circular enzyme-mimetic antibiosis and macrophage re-rousing. This article is protected by copyright. All rights reserved.
PubMed: 38943427
DOI: 10.1002/adma.202405659 -
Microbial Ecology Jun 2024Plastic pollution poses a worldwide environmental challenge, affecting wildlife and human health. Assessing the biodegradation capabilities of natural microbiomes in...
Plastic pollution poses a worldwide environmental challenge, affecting wildlife and human health. Assessing the biodegradation capabilities of natural microbiomes in environments contaminated with microplastics is crucial for mitigating the effects of plastic pollution. In this work, we evaluated the potential of landfill leachate (LL) and estuarine sediments (ES) to biodegrade polyethylene (PE), polyethylene terephthalate (PET), and polycaprolactone (PCL), under aerobic, anaerobic, thermophilic, and mesophilic conditions. PCL underwent extensive aerobic biodegradation with LL (99 ± 7%) and ES (78 ± 3%) within 50-60 days. Under anaerobic conditions, LL degraded 87 ± 19% of PCL in 60 days, whereas ES showed minimal biodegradation (3 ± 0.3%). PE and PET showed no notable degradation. Metataxonomics results (16S rRNA sequencing) revealed the presence of highly abundant thermophilic microorganisms assigned to Coprothermobacter sp. (6.8% and 28% relative abundance in anaerobic and aerobic incubations, respectively). Coprothermobacter spp. contain genes encoding two enzymes, an esterase and a thermostable monoacylglycerol lipase, that can potentially catalyze PCL hydrolysis. These results suggest that Coprothermobacter sp. may be pivotal in landfill leachate microbiomes for thermophilic PCL biodegradation across varying conditions. The anaerobic microbial community was dominated by hydrogenotrophic methanogens assigned to Methanothermobacter sp. (21%), pointing at possible syntrophic interactions with Coprothermobacter sp. (a H-producer) during PCL biodegradation. In the aerobic experiments, fungi dominated the eukaryotic microbial community (e.g., Exophiala (41%), Penicillium (17%), and Mucor (18%)), suggesting that aerobic PCL biodegradation by LL involves collaboration between fungi and bacteria. Our findings bring insights on the microbial communities and microbial interactions mediating plastic biodegradation, offering valuable perspectives for plastic pollution mitigation.
Topics: Biodegradation, Environmental; Microbiota; Microplastics; Waste Disposal Facilities; Bacteria; Water Pollutants, Chemical; Polyesters; Geologic Sediments; RNA, Ribosomal, 16S; Estuaries; Polyethylene; Polyethylene Terephthalates
PubMed: 38943017
DOI: 10.1007/s00248-024-02399-8 -
International Journal of Antimicrobial... Jun 2024Bacteroides fragilis is the most frequent cause of anaerobic bacteraemia. Although recent data suggest a rise in antimicrobial resistance (AMR) of this and other...
BACKGROUND
Bacteroides fragilis is the most frequent cause of anaerobic bacteraemia. Although recent data suggest a rise in antimicrobial resistance (AMR) of this and other anaerobic bacteria, surveillance remains limited due to a lack of both data availability and comparability. However, a newly introduced standardised method for antimicrobial susceptibility testing (AST) of anaerobic bacteria has made larger scale surveillance possible for the first time.
AIM
To investigate phenotypic AMR of Bacteroides fragilis isolates from bacteraemia across Europe in 2022.
METHODS
In a multicentre approach, clinical microbiology laboratories in Europe were invited to contribute results of AST for Bacteroides fragilis blood culture isolates (including only the first isolate per patient and year). AST of a selection of four antibiotics was performed locally by participating laboratories in a prospective or retrospective manner, using the new EUCAST disc diffusion method on fastidious anaerobe agar (FAA-HB).
RESULTS
A total of 16 European countries reported antimicrobial susceptibilities in 449 unique isolates of Bacteroides fragilis from blood cultures in 2022. Clindamycin demonstrated the highest resistance rates (20.9%, range 0 - 63.6%), followed by piperacillin-tazobactam (11.1%, 0 - 54.5%), meropenem (13.4%, 0 - 45.5%), and metronidazole (1.8%, 0 - 20.0%), all with wide variation between countries.
CONCLUSION
Considering that the mean resistance rates across Europe were higher than expected for three of the four anti-anaerobic antibiotics under surveillance, both local AST of clinically relevant isolates of Bacteroides fragilis and continued surveillance on an international level is warranted.
PubMed: 38942247
DOI: 10.1016/j.ijantimicag.2024.107241 -
Acta Microbiologica Et Immunologica... Jun 2024The aim of this prospective pilot study was to compare culture and microbiome results of the removed tonsils of patients with assumed distant focal disease (11 patients)...
The aim of this prospective pilot study was to compare culture and microbiome results of the removed tonsils of patients with assumed distant focal disease (11 patients) and those who underwent a tonsillectomy, due to other reasons, such as recurrent tonsillitis, tonsil stones or snoring (nine patients). Aerobic culture was carried out for samples taken from the surface of the tonsils by swabs before tonsillectomy for all 20 patients. The squeezed detritus and the tissue samples of removed tonsils, taken separately for the right and left tonsils, were incubated aerobically and anaerobically. The microbiome composition of tissue samples of removed tonsils was also evaluated. Based on the culture results of the deep samples Staphylococcus aureus was the dominating pathogen, besides a great variety of anaerobic and facultative anaerobic bacteria present in the oral microbiota in those patients who underwent tonsillectomy due to distant focal diseases. Microbiome study of the core tissue samples showed a great diversity on genus and species level among patients of the two groups however, S. aureus and Prevotella nigrescens were present in higher proportion in those, whose tonsils were removed due to distant focal diseases. Our results may support previous findings about the possible triggering role of S. aureus and P. nigrescens leading to distant focal diseases. Samples taken by squeezing the tonsils could give more information about the possible pathogenic/triggering bacteria than the surface samples cultured only aerobically.
PubMed: 38941152
DOI: 10.1556/030.2024.02279 -
MSystems Jun 2024We use metagenome-assembled genomes (MAGs) to understand single-carbon (C1) compound-cycling-particularly methane-cycling-microorganisms in montane riparian floodplain...
Diverse and unconventional methanogens, methanotrophs, and methylotrophs in metagenome-assembled genomes from subsurface sediments of the Slate River floodplain, Crested Butte, CO, USA.
We use metagenome-assembled genomes (MAGs) to understand single-carbon (C1) compound-cycling-particularly methane-cycling-microorganisms in montane riparian floodplain sediments. We generated 1,233 MAGs (>50% completeness and <10% contamination) from 50- to 150-cm depth below the sediment surface capturing the transition between oxic, unsaturated sediments and anoxic, saturated sediments in the Slate River (SR) floodplain (Crested Butte, CO, USA). We recovered genomes of putative methanogens, methanotrophs, and methylotrophs ( = 57). Methanogens, found only in deep, anoxic depths at SR, originate from three different clades (, , and ), each with a different methanogenesis pathway; putative methanotrophic MAGs originate from within the Archaea ( Methanoperedens) in anoxic depths and uncultured bacteria (. Binatia) in oxic depths. Genomes for canonical aerobic methanotrophs were not recovered. Methanoperedens were exceptionally abundant (~1,400× coverage, >50% abundance in the MAG library) in one sample that also contained aceticlastic methanogens, indicating a potential C1/methane-cycling hotspot. . Methylomirabilis MAGs from SR encode pathways for methylotrophy but do not harbor methane monooxygenase or nitrogen reduction genes. Comparative genomic analysis supports that one clade within the . Methylomirabilis genus is not methanotrophic. The genetic potential for methylotrophy was widespread, with over 10% and 19% of SR MAGs encoding a methanol dehydrogenase or substrate-specific methyltransferase, respectively. MAGs from uncultured archaea in the . Gimiplasmatales (UBA10834) contain pathways that may allow for anaerobic methylotrophic acetogenesis. Overall, MAGs from SR floodplain sediments reveal a potential for methane production and consumption in the system and a robust potential for methylotrophy.IMPORTANCEThe cycling of carbon by microorganisms in subsurface environments is of particular relevance in the face of global climate change. Riparian floodplain sediments contain high organic carbon that can be degraded into C1 compounds such as methane, methanol, and methylamines, the fate of which depends on the microbial metabolisms present as well as the hydrological conditions and availability of oxygen. In the present study, we generated over 1,000 MAGs from subsurface sediments from a montane river floodplain and recovered genomes for microorganisms that are capable of producing and consuming methane and other C1 compounds, highlighting a robust potential for C1 cycling in subsurface sediments both with and without oxygen. Archaea from the . Methanoperedens genus were exceptionally abundant in one sample, indicating a potential C1/methane-cycling hotspot in the Slate River floodplain system.
PubMed: 38940520
DOI: 10.1128/msystems.00314-24 -
Case Reports in Pediatrics 2024In infants and children, bacterial meningitis caused by anaerobic bacteria is rare. However, a serious infection with the anaerobe can occur in previously healthy...
In infants and children, bacterial meningitis caused by anaerobic bacteria is rare. However, a serious infection with the anaerobe can occur in previously healthy children with a peak incidence in preschool children and in adolescents. As the clinical presentation can be very similar to meningitis caused by aerobic bacteria, one should consider as the causative agent when preceded by or associated with otitis media with purulent otorrhea or mastoiditis, in combination with minimal or no improvement on empiric antibiotic treatment. As this pathogen can be difficult to culture, anaerobic cultures should be obtained. Prompt treatment with a third-generation cephalosporin and metronidazole should be initiated once suspected or confirmed. Surgical source control is often necessary, but even with adequate and prompt treatment, the morbidity and mortality in children with a meningitis remains high. In this report, we describe a case of meningitis in a previously healthy child and review the available literature.
PubMed: 38939326
DOI: 10.1155/2024/6365796 -
Cureus May 2024is a new genus of anaerobic bacteria discovered in the year 2000. It is one of the most common bacteria present in the host microbial flora of dental plaque. The levels...
Comparative Evaluation of Mogibacterium timidum in the Subgingival Plaque of Periodontally Healthy and Chronic Periodontitis Patients: A Real-Time Polymerase Chain Reaction (PCR) Study.
BACKGROUND
is a new genus of anaerobic bacteria discovered in the year 2000. It is one of the most common bacteria present in the host microbial flora of dental plaque. The levels of are supposedly higher in inflammatory conditions.
AIMS AND OBJECTIVES
This study aimed to quantify the levels of species in the subgingival plaque samples of healthy patients and patients with chronic periodontitis.
MATERIALS AND METHODS
A total of 24 samples of the subgingival plaque, 12 healthy samples and 12 samples of chronic periodontitis patients, were collected in a buffer solution using a sterile Gracey curette. These samples were then sent to a laboratory for real-time polymerase chain reaction (PCR) testing.
RESULTS
was found in higher quantities in plaque samples taken from chronic periodontitis patients when compared to healthy patients.
CONCLUSION
can be said to be associated with chronic periodontitis condition. Further studies are required to know the exact nature of the pathogen.
PubMed: 38939247
DOI: 10.7759/cureus.61211 -
Plant Disease Jun 2024Blackleg and soft rot diseases represent a major threat to the health of potato () and other vegetable, ornamental and fruit crops worldwide; their main causal agents...
Blackleg and soft rot diseases represent a major threat to the health of potato () and other vegetable, ornamental and fruit crops worldwide; their main causal agents are species of and . In May 2022, 60% of potato plants (cv. Spunta) in a production field in Córdoba, Argentina (31°32'36''S 64°09'46''W) showed soft rot, blackleg and wilt. To isolate the causal agent, decayed plant tissues were disinfected in 2% NaClO, macerated in sterile water and streaked on crystal violet pectate (CVP) medium. Plates were incubated at 28°C for 48 h. Colonies that produced a pit on CVP medium were purified on nutrient agar. Two of the isolates, called 1Aia and 1B, were characterized by tests commonly employed for the identification of pectinolytic bacteria (Schaad et al. 2001). Both produced Gram-negative rods that were facultatively anaerobic, oxidase negative, nonfluorescent on King´s B, resistant to erythromycin and caused soft rot of potato slices. In addition, these isolates did not produce the blue pigment indigoidine and grew on nutrient glucose agar containing 5% NaCl. Phenotypic characteristics of the isolates 1Aia and 1B were compatible with spp. Genomic DNA was extracted using the commercially available Wizard® Genomic DNA Purification Kit (Promega) according to the manufacturer's instructions for the purification of DNA from Gram-negative bacteria. The isolates were positive in a PCR assay for (Duarte et al. 2004). The purified DNA of isolate 1Aia was used to construct a pooled Illumina library, which was sequenced at the Genomics Unit from the National Institute of Agricultural Technology (INTA, Argentina), by using high-throughput Illumina sequencing technology. Average nucleotide identity (ANI) calculation performed by FastANI v0.1.3 (Jain et al. 2018) showed 96.11% identity between the genome of the type strain LMG 21371 of (Acc. no. JQOE00000000) and our strain 1Aia (Acc. no. JAYGXQ000000000). For pathogenicity test, 3-weeks-old potato plants (cv. Spunta) planted in pots were infiltrated with 10 µl of a bacterial suspension (1x107 CFU/ml) 5 cm above the base of the stem using a sterile syringe. Negative controls were infiltrated with sterile water. Plants were kept under greenhouse conditions and regularly watered. The experiment was performed twice with six plants per treatment. Two days after inoculation, plants treated with strain 1Aia or 1B showed necrotic lesions on the stems and tubers soft rot symptoms while control plants remained asymptomatic. To fulfill Koch´s postulates, bacteria were re-isolated from symptomatic plants. Re-isolated bacteria, called 1Aia d and 1B d, were confirmed as according to biochemical and PCR results, as outlined above. Also, the % ANI value between isolates 1Aia and 1Aia d was 99.99% (Acc. no. JAYGXR000000000). To our knowledge, this is the first report of the occurrence of in Argentina. This pathogen has been observed causing blackleg and tuber soft rot on potato in Brazil (Duarte et al. 2004), Netherlands (Nunes Leite et al. 2014), Switzerland (de Werra et al. 2015), Russia (Voronina et al. 2019), Serbia (Loc et al. 2022) and USA (Zhang et al. 2023), among other countries worldwide. Due to the important economic and nutritional value of the crop, the distribution of needs to be investigated and monitored in order to develop effective control strategies.
PubMed: 38937930
DOI: 10.1094/PDIS-03-24-0558-PDN