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Frontiers in Microbiology 2024Previous studies have reported the role of some species of acidophilic bacteria in accelerating the dissolution of goethite under aerobic and anaerobic conditions. This...
Previous studies have reported the role of some species of acidophilic bacteria in accelerating the dissolution of goethite under aerobic and anaerobic conditions. This has relevance for environments impacted by acid mine drainage and for the potential bioleaching of limonitic laterite ores. In this study, natural well-characterized goethite mineral samples and synthetic goethite were used in aerobic and anaerobic laboratory batch culture incubation experiments with ferric iron-reducing, acidophilic bacteria, including the lithoautotrophic species , and , as well as two strains of the organoheterotrophic species . All bacteria remained alive throughout the experiments and efficiently reduced soluble ferric iron in solution in positive control assays. However, goethite dissolution was low to negligible in all experimental assays with natural goethite, while some dissolution occurred with synthetic goethite in agreement with previous publications. The results indicate that ferric iron-reducing microbial activity at low pH is less relevant for goethite dissolution than the oxidation of elemental sulfur to sulfuric acid. Microbial ferric iron reduction enhances but does not initiate goethite dissolution in very acidic liquors.
PubMed: 38846564
DOI: 10.3389/fmicb.2024.1360018 -
IUCrData May 2024The use of acetic acid (HOAc) in a reaction between CuCl·2HO and secnid-azole, an active pharmaceutical ingredient useful in the treatment against a variety of...
The use of acetic acid (HOAc) in a reaction between CuCl·2HO and secnid-azole, an active pharmaceutical ingredient useful in the treatment against a variety of anaerobic Gram-positive and Gram-negative bacteria, affords the title complex, [CuCl(CHNO)]. This compound was previously synthesized using ethanol as solvent, although its crystal structure was not reported [Betanzos-Lara (2013 ▸). , , 94-100]. In the mol-ecular complex, the Cu cation is situated at an inversion centre and displays a square-planar coordination environment. There is a hydrogen-bonded framework based on inter-molecular O-H⋯Cl inter-actions, characterized by H⋯Cl separations of 2.28 (4) Å and O-H⋯Cl angles of 175 (3)°. The resulting supra-molecular network is based on (18) ring motifs, forming chains in the [010] direction.
PubMed: 38846553
DOI: 10.1107/S2414314624003766 -
Frontiers in Microbiology 2024The composition of membrane lipids varies in a number of ways as adjustment to growth conditions. Variations in head group composition and carbon skeleton and degree of...
The composition of membrane lipids varies in a number of ways as adjustment to growth conditions. Variations in head group composition and carbon skeleton and degree of unsaturation of glycerol-bound acyl or alkyl chains results in a high structural complexity of the lipidome of bacterial cells. We studied the lipidome of the mesophilic, sulfate-reducing bacterium, strain PF2803 by ultra-high-pressure liquid chromatography coupled with high-resolution tandem mass spectrometry (UHPLC-HRMS). This anaerobic bacterium has been previously shown to produce high amounts of mono-and di-alkyl glycerol ethers as core membrane lipids. Our analyses revealed that these core lipids occur with phosphatidylethanomamine (PE) and phosphatidylglycerol (PG) head groups, representing each approximately one third of the phospholipids. The third class was a novel group of phospholipids, i.e., cardiolipins (CDLs) containing one (monoether/triester) to four (tetraether) ether-linked saturated straight-chain or methyl-branched alkyl chains. Tetraether CDLs have been shown to occur in archaea (with isoprenoid alkyl chains) but have not been previously reported in the bacterial Domain. Structurally related CDLs with one or two alkyl/acyl chains missing, so-called monolyso-and dilyso-CDLs, were also observed. The potential biosynthetic pathway of these novel CDLs was investigated by examining the genome of . Three CDL synthases were identified; one catalyzes the condensation of two PGs, the other two are probably involved in the condensation of a PE with a PG. A heterologous gene expression experiment showed the production of dialkylglycerols upon anaerobic expression of the glycerol ester reductase enzyme of in . Reduction of the ester bonds probably occurs first at the -1 and subsequently at the -2 position after the formation of PEs and PGs.
PubMed: 38841066
DOI: 10.3389/fmicb.2024.1404328 -
Proceedings of the National Academy of... Jun 2024Understanding how microbial lipidomes adapt to environmental and nutrient stress is crucial for comprehending microbial survival and functionality. Certain anaerobic...
Understanding how microbial lipidomes adapt to environmental and nutrient stress is crucial for comprehending microbial survival and functionality. Certain anaerobic bacteria can synthesize glycerolipids with ether/ester bonds, yet the complexities of their lipidome remodeling under varying physicochemical and nutritional conditions remain largely unexplored. In this study, we thoroughly examined the lipidome adaptations of strain PF2803, a mesophilic anaerobic sulfate-reducing bacterium known for its high proportions of alkylglycerol ether lipids in its membrane, under various cultivation conditions including temperature, pH, salinity, and ammonium and phosphorous concentrations. Employing an extensive analytical and computational lipidomic methodology, we identified an assemblage of nearly 400 distinct lipids, including a range of glycerol ether/ester lipids with various polar head groups. Information theory-based analysis revealed that temperature fluctuations and phosphate scarcity profoundly influenced the lipidome's composition, leading to an enhanced diversity and specificity of novel lipids. Notably, phosphorous limitation led to the biosynthesis of novel glucuronosylglycerols and sulfur-containing aminolipids, termed butyramide cysteine glycerols, featuring various ether/ester bonds. This suggests a novel adaptive strategy for anaerobic heterotrophs to thrive under phosphorus-depleted conditions, characterized by a diverse array of nitrogen- and sulfur-containing polar head groups, moving beyond a reliance on conventional nonphospholipid types.
Topics: Phosphorus; Sulfur; Lipidomics; Nitrogen; Adaptation, Physiological; Sulfates; Bacteria, Anaerobic; Anaerobiosis
PubMed: 38833476
DOI: 10.1073/pnas.2400711121 -
Microbiology Spectrum Jun 2024Rice anaerobic fermentation is a significant source of greenhouse gas (GHG) emissions, and in order to efficiently utilize crop residue resources to reduce GHG...
Rice anaerobic fermentation is a significant source of greenhouse gas (GHG) emissions, and in order to efficiently utilize crop residue resources to reduce GHG emissions, rice straw anaerobic fermentation was regulated using lactic acid bacteria (LAB) inoculants (FG1 and TH14), grass medium (GM) to culture LAB, and (AC). Microbial community, GHG emission, dry matter (DM) loss, and anaerobic fermentation were analyzed using PacBio single-molecule real-time and anaerobic fermentation system. The epiphytic microbial diversity of fresh rice straw was extremely rich and contained certain nutrients and minerals. During ensiling, large amounts of GHG such as carbon dioxide are produced due to plant respiration, enzymatic hydrolysis reactions, and proliferation of aerobic bacteria, resulting in energy and DM loss. Addition of FG1, TH14, and AC alone improved anaerobic fermentation by decreasing pH and ammonia nitrogen content ( < 0.05) and increased lactic acid content ( < 0.05) when compared to the control, and GM showed the same additive effect as LAB inoculants. Microbial additives formed a co-occurrence microbial network system dominated by LAB, enhanced the biosynthesis of secondary metabolites, diversified the microbial metabolic environment and carbohydrate metabolic pathways, weakened the amino acid metabolic pathways, and made the anaerobic fermentation cleaner. This study is of great significance for the effective utilization of crop straw resources, the promotion of sustainable livestock production, and the reduction of GHG emissions.IMPORTANCETo effectively utilize crop by-product resources, we applied microbial additives to silage fermentation of fresh rice straw. Fresh rice straw is extremely rich in microbial diversity, which was significantly reduced after silage fermentation, and its nutrients were well preserved. Silage fermentation was improved by microbial additives, where the combination of cellulase and lactic acid bacteria acted as enzyme-bacteria synergists to promote lactic acid fermentation and inhibit the proliferation of harmful bacteria, such as protein degradation and gas production, thereby reducing GHG emissions and DM losses. The microbial additives accelerated the formation of a symbiotic microbial network system dominated by lactic acid bacteria, which regulated silage fermentation and improved microbial metabolic pathways for carbohydrates and amino acids, as well as biosynthesis of secondary metabolites.
PubMed: 38832787
DOI: 10.1128/spectrum.00520-24 -
Heliyon May 2024Disturbances in the oral microbiota may be due to several mechanisms and factors, such as smoking. An imbalance in oral bacteria may result in changes to the innate...
Disturbances in the oral microbiota may be due to several mechanisms and factors, such as smoking. An imbalance in oral bacteria may result in changes to the innate immune system and the development of periodontal disease. This study aimed to investigate the distribution of oral microbiota in smokers and non-smokers in a South African population using subgingival plaque samples. From the 128 recruited participants, 57 were identified as smokers (serum cotinine: >15 ng/ml). Analysis of 16S rRNA gene sequencing demonstrated significant differences between the two groups with a reduced abundance of Actinobacteria in smokers. Fusobacterium and Campylobacter were found in higher abundance, while a lower abundance of Leptotrichia, Actinomyces, Corynebacterium, and Lautropia were observed. This study highlighted significant differences in the oral microbiota of smokers, indicating an abundance of anaerobic gram-negative bacteria. These findings suggest that smoking allows certain oral microorganisms to gain dominance, thereby predisposing individuals to periodontal disease development and progression.
PubMed: 38831830
DOI: 10.1016/j.heliyon.2024.e31559 -
Respirology Case Reports Jun 2024Odontogenic infections can spread to the respiratory tract. Despite the known role of as the primary pathogen in periodontitis, the association between infection and...
Odontogenic infections can spread to the respiratory tract. Despite the known role of as the primary pathogen in periodontitis, the association between infection and risk of pneumonia or lung abscess remains unknown. In this report, we present a case of lung abscess caused by infection. The pathogen was detected by metagenomic next-generation sequencing (mNGS) in the bronchoalveolar lavage fluid of the patient. The clinical characteristics and possible mechanisms of the infection are discussed. is a conditional pathogen that can cause lung abscess in the presence of helper bacteria and reduced host immune status. The course of treatment should be personalized and might be longer than 3 months.
PubMed: 38831800
DOI: 10.1002/rcr2.1391 -
Microbial Ecology Jun 2024Denitrification and anaerobic ammonium oxidation (anammox) are key processes for nitrogen removal in aquaculture, reducing the accumulated nitrogen nutrients to nitrogen...
Denitrification and anaerobic ammonium oxidation (anammox) are key processes for nitrogen removal in aquaculture, reducing the accumulated nitrogen nutrients to nitrogen gas or nitrous oxide gas. Complete removal of nitrogen from aquaculture systems is an important measure to solve environmental pollution. In order to evaluate the nitrogen removal potential of marine aquaculture ponds, this study investigated the denitrification and anammox rates, the flux of nitrous oxide (NO) at the water-air interface, the sediment microbial community structure, and the gene expression associated with the nitrogen removal process in integrated multi-trophic aquaculture (IMTA) ponds (Apostistius japonicus-Penaeus japonicus-Ulva) with different culture periods. The results showed that the denitrification and anammox rates in sediments increased with the increase of cultivation periods and depth, and there was no significant difference in nitrous oxide gas flux at the water-air interface between different cultivation periods (p > 0.05). At the genus and phylum levels, the abundance of microorganisms related to nitrogen removal reactions in sediments changed significantly with the increase of cultivation period and depth, and was most significantly affected by the concentration of particulate organic nitrogen (PON) in sediments. The expression of denitrification gene (narG, nirS, nosZ) in surface sediments was significantly higher than that in deep sediments (p < 0.05), and was negatively correlated with denitrification rate. All samples had a certain anammox capacity, but no known anammox bacteria were found in the microbial diversity detection, and the expression of gene (hzsB) related to the anammox process was extremely low, which may indicate the existence of an unknown anammox bacterium. The data of this study showed that the IMTA culture pond had a certain potential for nitrogen removal, and whether it could make a contribution to reducing the pollution of culture wastewater still needed additional practice and evaluation, and also provided a theoretical basis for the nitrogen removal research of coastal mariculture ponds.
Topics: Nitrogen; Aquaculture; Denitrification; Bacteria; Ponds; Microbiota; Animals; Penaeidae; Nitrous Oxide; Geologic Sediments; Oxidation-Reduction; Ammonium Compounds
PubMed: 38831142
DOI: 10.1007/s00248-024-02378-z -
Radiology Case Reports Aug 2024Mycetoma, commonly known as Madura foot, is a chronic and progressively destructive granulomatous disease caused by a fungus or anaerobic filamentous bacteria that...
Mycetoma, commonly known as Madura foot, is a chronic and progressively destructive granulomatous disease caused by a fungus or anaerobic filamentous bacteria that affects the skin, subcutaneous tissue, and bones primarily in tropical and subtropical regions, with males between the ages of 20-40 having occupational exposure to outdoor environments, such as farming, predominantly affected. It is one of the World Health Organization's 17 "neglected tropical diseases," characterized by a clinical trial of localized mass-like soft tissue injury with draining sinuses that discharge grains of infectious material. Here, we present a case report of a 40-year-old male with type 2 diabetes mellitus and a history of fieldwork, who exhibited early manifestations of mycetoma. Unlike the typical diffuse presentation seen in advanced cases, this patient's early presentation prompted diagnostic challenges due to its atypical nature. We highlight the importance of recognizing the early signs of mycetoma, particularly in individuals with predisposing factors such as diabetes and occupational exposure. Diagnostic dilemmas may arise, leading to potential misdiagnosis. Additionally, we emphasize the crucial role of biopsy in confirming the diagnosis, alongside imaging techniques, to facilitate timely intervention and management, thereby significantly impacting patient outcomes.
PubMed: 38827041
DOI: 10.1016/j.radcr.2024.05.007 -
The Journal of Biological Chemistry May 2024Antibiotic resistant Enterobacterales pose a major threat to healthcare systems worldwide, necessitating the development of novel strategies to fight such hard-to-kill...
Antibiotic resistant Enterobacterales pose a major threat to healthcare systems worldwide, necessitating the development of novel strategies to fight such hard-to-kill bacteria. One potential approach is to develop molecules that force bacteria to hyper-activate prodrug antibiotics, thus rendering them more effective. In the present work, we aimed to obtain proof-of-concept data to support that small molecules targeting transcriptional regulators can potentiate the antibiotic activity of the prodrug metronidazole (MTZ) against Escherichia coli under aerobic conditions. By screening a chemical library of small molecules a series of structurally related molecules were identified that had little inherent antibiotic activity, but showed substantial activity in combination with ineffective concentrations of MTZ. Transcriptome analyses, functional genetics, thermal shift assays and electrophoretic mobility shift assays were then used to demonstrate that these MTZ boosters target the transcriptional repressor MarR, resulting in the up-regulation of the marRAB operon and its downstream MarA regulon. The associated upregulation of the flavin-containing nitro-reductase; NfsA was then shown to be critical for the booster mediated potentiation of MTZ antibiotic activity. Transcriptomic studies, biochemical assays and electron paramagnetic resonance measurements were then used to show that under aerobic conditions, NfsA catalyzed 1-electron reduction of MTZ to the MTZ radical anion which in turn induced lethal DNA damage in E. coli. This work reports the first example of prodrug boosting in Enterobacterales by transcriptional modulators and highlights that MTZ antibiotic activity can be chemically induced under anaerobic growth conditions.
PubMed: 38825006
DOI: 10.1016/j.jbc.2024.107431