RESUMO
Methanogenic hydrocarbon degradation can be carried out by archaea that couple alkane oxidation directly to methanogenesis, or by syntrophic associations of bacteria with methanogenic archaea. However, metagenomic analyses of methanogenic environments have revealed other archaea with potential for alkane degradation but apparent inability to form methane, suggesting the existence of other modes of syntrophic hydrocarbon degradation. Here, we provide experimental evidence supporting the existence of a third mode of methanogenic degradation of hydrocarbons, mediated by syntrophic cooperation between archaeal partners. We collected sediment samples from a hot spring sediment in Tengchong, China, and enriched Hadarchaeota under methanogenic conditions at 60 °C, using hexadecane as substrate. We named the enriched archaeon Candidatus Melinoarchaeum fermentans DL9YTT1. We used 13C-substrate incubations, metagenomic, metatranscriptomic and metabolomic analyses to show that Ca. Melinoarchaeum uses alkyl-coenzyme M reductases (ACRs) to activate hexadecane via alkyl-CoM formation. Ca. Melinoarchaeum likely degrades alkanes to carbon dioxide, hydrogen and acetate, which can be used as substrates by hydrogenotrophic and acetoclastic methanogens such as Methanothermobacter and Methanothrix.
Assuntos
Alcanos , Archaea , Metano , Alcanos/metabolismo , Metano/metabolismo , Archaea/metabolismo , Archaea/genética , Fontes Termais/microbiologia , Sedimentos Geológicos/microbiologia , Filogenia , Oxirredutases/metabolismo , Oxirredutases/genética , China , Dióxido de Carbono/metabolismo , Biodegradação Ambiental , OxirreduçãoRESUMO
The upper mantle is critical for our understanding of terrestrial magmatism, crust formation, and element cycling between Earth's solid interior, hydrosphere, atmosphere, and biosphere. Mantle composition and evolution have been primarily inferred by surface sampling and indirect methods. We recovered a long (1268-meter) section of serpentinized abyssal mantle peridotite interleaved with thin gabbroic intrusions. We find depleted compositions with notable variations in mantle mineralogy controlled by melt flow. Dunite zones have predominantly intermediate dips, in contrast to the originally steep mantle fabrics, indicative of oblique melt transport. Extensive hydrothermal fluid-rock interaction is recorded across the full depth of the core and is overprinted by oxidation in the upper 200 meters. Alteration patterns are consistent with vent fluid composition in the nearby Lost City hydrothermal field.
RESUMO
Most microorganisms resist pure cultivation under conventional laboratory conditions. One of the primary issues for this un-culturability is the absence of biologically produced growth-promoting factors in traditionally defined growth media. However, whether cultivating microbes by providing spent culture supernatant of pivotal microbes in the growth medium can be an effective approach to overcome this limitation is still an under-explored area of research. Here, we used the spent culture medium (SCM) method to isolate previously uncultivated marine bacteria and compared the efficiency of this method with the traditional cultivation (TC) method. In the SCM method, Ca. Bathyarchaeia-enriched supernatant (10%) was used along with recalcitrant organic substrates such as lignin, humic acid, and organic carbon mixture. Ca. Bathyarchaeia, a ubiquitous class of archaea, have the capacity to produce metabolites, making their spent culture supernatant a key source to recover new bacterial stains. Both cultivation methods resulted in the recovery of bacterial species from the phyla Pseudomonadota, Bacteroidota, Actinomycetota, and Bacillota. However, our SCM approach also led to the recovery of species from rarely cultivated groups, such as Planctomycetota, Deinococcota, and Balneolota. In terms of the isolation of new taxa, the SCM method resulted in the cultivation of 80 potential new strains, including one at the family, 16 at the genus, and 63 at the species level, with a novelty ratio of ~ 35% (80/219). In contrast, the TC method allowed the isolation of ~ 10% (19/171) novel strains at species level only. These findings suggest that the SCM approach improved the cultivation of novel and diverse bacteria.
RESUMO
Reactive iron (FeR) serves as an important sink of organic carbon (OC) in marine surface sediments, which preserves approximately 20% of total OC (TOC) as reactive iron-bound OC (FeR-OC). However, the fate of FeR-OC in subseafloor sediments and its availability to microorganisms, remain undetermined. Here, we reconstructed continuous FeR-OC records in two sediment cores of the northern South China Sea encompassing the suboxic to methanic biogeochemical zones and reaching a maximum age of ~100 kyr. The downcore FeR-OC contributes a relatively stable proportion of 13.3 ± 3.2% to TOC. However, distinctly lower values of less than 5% of TOC, accompanied by notable 13C depletion of FeR-OC, are observed in the sulfate-methane transition zone (SMTZ). FeR-OC is suggested to be remobilized by microbially mediated reductive dissolution of FeR and subsequently remineralized, the flux of which is 18-30% of the methane consumption in the SMTZ. The global reservoir of FeR-OC in microbially active Quaternary marine sediments could be 19-46 times the size of the atmospheric carbon pool. Thus, the FeR-OC pool may support subseafloor microorganisms and contribute to regulating Earth's carbon cycle.
RESUMO
The SeqCode, formally called the Code of Nomenclature of Prokaryotes Described from Sequence Data, is a new code of nomenclature in which genome sequences are the nomenclatural types for the names of prokaryotic species. While similar to the International Code of Nomenclature of Prokaryotes (ICNP) in structure and rules of priority, it does not require the deposition of type strains in international culture collections. Thus, it allows for the formation of permanent names for uncultured prokaryotes whose nearly complete genome sequences have been obtained directly from environmental DNA as well as other prokaryotes that cannot be deposited in culture collections. Because the diversity of uncultured prokaryotes greatly exceeds that of readily culturable prokaryotes, the SeqCode is the only code suitable for naming the majority of prokaryotic species. The start date of the SeqCode was January 1, 2022, and the online Registry (https://seqco.de/) was created to ensure valid publication of names. The SeqCode recognizes all names validly published under the ICNP before 2022. After that date, names validly published under the SeqCode compete with ICNP names for priority. As a result, species can have only one name, either from the SeqCode or ICNP, enabling effective communication and the creation of unified taxonomies of uncultured and cultured prokaryotes. The SeqCode is administered by the SeqCode Committee, which is comprised of the SeqCode Community and elected administrative components. Anyone with an interest in the systematics of prokaryotes is encouraged to join the SeqCode Community and participate in the development of this resource.
RESUMO
A large number of oceanic metagenomic data and environmental metadata have been published. However, most studies focused on limited ecosystems using different analysis tools, making it challenging to integrate these data into robust results and comprehensive global understanding of marine microbiome. Here, we constructed a systematic and quantitative analysis platform, the Microbiome Atlas/Sino-Hydrosphere for Ocean Ecosystem (MASH-Ocean: https://www.biosino.org/mash-ocean/), by integrating global marine metagenomic data and a unified data processing flow. MASH-Ocean 1.0 comprises 2147 metagenomic samples with five analysis modules: sample view, diversity, function, biogeography, and interaction network. This platform provides convenient and stable support for researchers in microbiology, environmental science, and biogeochemistry, to ensure the integration of omics data generated from hydrosphere ecosystems, to bridge the gap between elusive omics data and biological, ecological, and geological discovery, ultimately to foster the formation of a comprehensive atlas for aquatic environments.
RESUMO
In this work, a triphenylamine-benzofuran-derived fluorescent probe TBSF was developed for monitoring the sulfite level in Chinese medicinal materials and imaging in living cells. In the testing system, under 445 nm excitation, TBSF responded to sulfite steadily with a 540 nm fluorescence reporting signal. The testing system showed advantages including high sensitivity, rapid response, and high selectivity. In particular, TBSF achieved the sulfite detection in the water decoction of Chinese medicinal materials from both addition and excessive fumigation. It also realized the intracellular imaging of both exogenous and endogenous sulfite in living HepG2 cells. The imaging in water decoction-treated cells inferred the potential for the interdisciplinary detection.
Assuntos
Benzofuranos , Corantes Fluorescentes , Espectrometria de Fluorescência , Sulfitos , Sulfitos/análise , Corantes Fluorescentes/química , Humanos , Benzofuranos/química , Benzofuranos/análise , Células Hep G2 , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/análise , Compostos de Anilina/química , Imagem ÓpticaRESUMO
Isoprenoids and their derivatives, essential for all cellular life on Earth, are particularly crucial in archaeal membrane lipids, suggesting that their biosynthesis pathways have ancient origins and play pivotal roles in the evolution of early life. Despite all eukaryotes, archaea, and a few bacterial lineages being known to exclusively use the mevalonate (MVA) pathway to synthesize isoprenoids, the origin and evolutionary trajectory of the MVA pathway remain controversial. Here, we conducted a thorough comparison and phylogenetic analysis of key enzymes across the four types of MVA pathway, with the particular inclusion of metagenome assembled genomes (MAGs) from uncultivated archaea. Our findings support an archaeal origin of the MVA pathway, likely postdating the divergence of Bacteria and Archaea from the Last Universal Common Ancestor (LUCA), thus implying the LUCA's enzymatic inability for isoprenoid biosynthesis. Notably, the Asgard archaea are implicated in playing central roles in the evolution of the MVA pathway, serving not only as putative ancestors of the eukaryote- and Thermoplasma-type routes, but also as crucial mediators in the gene transfer to eukaryotes, possibly during eukaryogenesis. Overall, this study advances our understanding of the origin and evolutionary history of the MVA pathway, providing unique insights into the lipid divide and the evolution of early life.
RESUMO
This study investigates the molecular mechanism of HMGA2-mediated regulation of IGFBP2 expression in the PI3K/AKT/VEGFA signaling pathway, which is involved in angiogenesis and LUAD metastasis. Target genes with prognostic implications for LUAD patients were selected using bioinformatics, and previously published literature was referenced to predict the molecular regulatory mechanisms. A549 cells were used for in vitro validation. Cell proliferation and viability were assessed using CCK-8 and EdU assays, while cell migration ability was evaluated using Transwell and wound healing assays. Changes in angiogenesis were examined using an angiogenesis assay. The targeted binding of HMGA2 with the IGFBP2 promoter was confirmed through dual luciferase reporter gene experiments and ChIP assays. In vivo validation was performed using a xenograft mouse model, and changes in angiogenesis and tumor metastasis were observed using western blot, immunofluorescence, and H&E staining. Bioinformatics analysis revealed that HMGA2 was one of the AAGs that differed between normal individuals and LUAD patients and could serve as a critical mRNA for predicting LUAD prognosis. Results from in vitro experiments demonstrated that the expression of the HMGA2 gene was significantly upregulated in LUAD cell lines. Through mediating the expression of IGFBP2, the HMGA2 gene activated the PI3K/AKT/VEGFA signaling pathway, promoting the proliferation, migration, and angiogenesis of A549 cells. In vivo, animal experiments further confirmed that HMGA2 facilitated angiogenesis and the development and metastasis of LUAD through mediating IGFBP2 expression and activating the PI3K/AKT/VEGFA signaling pathway. HMGA2 promotes angiogenesis and healthy growth and metastasis of LUAD by activating the PI3K/AKT/VEGFA signaling pathway by mediating IGFBP2 expression.
Assuntos
Neoplasias Pulmonares , MicroRNAs , Humanos , Animais , Camundongos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , MicroRNAs/genética , Angiogênese , Regulação Neoplásica da Expressão Gênica , Transdução de Sinais/genética , Proliferação de Células/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Neoplasias Pulmonares/patologia , Fator A de Crescimento do Endotélio Vascular/genéticaRESUMO
In this study we describe the first cultured representative of Candidatus Synoicihabitans genus, a novel strain designated as LMO-M01T, isolated from deep-sea sediment of South China Sea. This bacterium is a facultative aerobe, Gram-negative, non-motile, and has a globular-shaped morphology, with light greenish, small, and circular colonies. Analysis of the 16S rRNA gene sequences of strain LMO-M01T showed less than 93% similarity to its closest cultured members. Furthermore, employing advanced phylogenomic methods such as comparative genome analysis, average nucleotide identity (ANI), average amino acids identity (AAI), and digital DNA-DNA hybridization (dDDH), placed this novel species within the candidatus genus Synoicihabitans of the family Opitutaceae, Phylum Verrucomicrobiota. The genomic analysis of strain LMO-M01T revealed 175 genes, encoding putative carbohydrate-active enzymes. This suggests its metabolic potential to degrade and utilize complex polysaccharides, indicating a significant role in carbon cycling and nutrient turnover in deep-sea sediment. In addition, the strain's physiological capacity to utilize diverse biopolymers such as lignin, xylan, starch, and agar as sole carbon source opens up possibilities for sustainable energy production and environmental remediation. Moreover, the genome sequence of this newly isolated strain has been identified across diverse ecosystems, including marine sediment, fresh water, coral, soil, plants, and activated sludge highlighting its ecological significance and adaptability to various environments. The recovery of strain LMO-M01T holds promise for taxonomical, ecological and biotechnological applications. Based on the polyphasic data, we propose that this ecologically important strain LMO-M01T represents a novel genus (previously Candidatus) within the family Opitutaceae of phylum Verrucomicrobiota, for which the name Synoicihabitans lomoniglobus gen. nov., sp. nov. was proposed. The type of strain is LMO-M01T (= CGMCC 1.61593T = KCTC 92913T).
Assuntos
DNA Bacteriano , Sedimentos Geológicos , Filogenia , RNA Ribossômico 16S , Análise de Sequência de DNA , Sedimentos Geológicos/microbiologia , China , RNA Ribossômico 16S/genética , DNA Bacteriano/genética , Água do Mar/microbiologia , Hibridização de Ácido Nucleico , Técnicas de Tipagem Bacteriana , Genoma Bacteriano/genética , Composição de Bases , Ácidos Graxos/análiseRESUMO
Red lead is commonly employed as a red pigment in numerous valuable cultural artifacts. Raman spectrometry has been widely employed as the primary tool in many nondestructive studies on red lead. Therefore, it is necessary to evaluate and study the impact of lasers on the pigment. The degradation of red lead induced by a 532 nm laser is investigated using micro-Raman spectroscopy. At room temperature, red lead begins to degrade into ß-PbO when the power density of the 532 nm laser reaches approximately 5.1 × 104 W/cm2 (laser: 532 nm, objective: 50×). At this point, the temperature at the focus of the sample is estimated to be at least 500 °C, aided by the Raman peak shift of ß-PbO. Furthermore, the power density of the laser-induced degradation decreases as the temperature of the red lead increases. Hence, the degradation of red lead can be attributed to the photothermal effect. The temperature rise can be explained by two factors. First, red lead exhibits a high absorbance of approximately 0.5942 at 532 nm. Second, red lead has significantly low thermal diffusivity and conductivity, measuring 0.039 mm2·s-1 and 0.078 W·m-1·K-1, respectively, which leads to heat accumulation at the focal point of the laser beam. To better preserve cultural heritage, the appropriate laser power should be prioritized when the degradation process is caused by the thermal effect of laser irradiation.
RESUMO
BACKGROUND: Non-small cell lung cancer (NSCLC) is a prevalent and aggressive malignancy responsible for a significant number of cancer-related deaths worldwide. Unraveling the molecular mechanisms governing NSCLC growth and metastasis is crucial for the identification of novel therapeutic targets and the development of effective anti-cancer strategies. One such mechanism of interest is the involvement of METTL14, an RNA methyltransferase implicated in various cellular processes, in NSCLC progression. OBJECTIVE: The objective of this study was to investigate the role of METTL14 in NSCLC development and metastasis and to elucidate the underlying molecular mechanisms. By understanding the impact of METTL14 on NSCLC pathogenesis, the study aimed to identify potential avenues for targeted therapies in NSCLC treatment. METHODS: We used bioinformatics and high-throughput transcriptome sequencing analyses to screen regulatory mechanisms affecting NSCLC. The Kaplan-Meier method assessed the correlation between METTL14 expression and the prognosis of NSCLC patients. The effects of manipulated METTL14 on malignant phenotypes of NSCLC cells were examined by colony formation assay, flow cytometry, scratch assay, and Transwell assay. The tumorigenic capacity and metastatic potential of NSCLC cells in vivo were evaluated in nude mice. RESULTS: METTL14 was overexpressed in NSCLC tissues and cell lines. Its high expression indicated a poor prognosis for NSCLC patients. METTL14 silencing promoted apoptosis and repressed proliferation, migration, and invasion of NSCLC cells. miR-93-5p targeted and inhibited TXNIP. METTL14 increased miR-93-5p expression and matured pri-miR-93-5p through m6A alteration to inhibit TXNIP, thereby inhibiting NSCLC cell apoptosis. By controlling the miR-93-5p/TXNIP axis, METTL14 increased the tumorigenic potential and lung metastasis of NSCLC cells in nude mice. CONCLUSION: This study revealed a role for METTL14 in the contribution to NSCLC development and metastasis and identified METTL14 as a potential target for NSCLC treatment.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , MicroRNAs , Animais , Camundongos , Humanos , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Pulmonares/metabolismo , Camundongos Nus , Linhagem Celular Tumoral , Proliferação de Células/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Proteínas de Transporte/genética , Metiltransferases/genética , Metiltransferases/metabolismoRESUMO
Objective: We probed into the significance of METTL3 in the maturation process of pri-miR-21-5p. We specifically investigated its impact on the regulation of FDX1 and its involvement in the progression of non-small-cell lung cancer (NSCLC). Methods: The Cancer Genome Atlas (TCGA) identified NSCLC factors. Methylation-specific PCR (MSP), clonogenic tests and flow cytometry analyzed cells. Methylated RNA immunoprecipitation (Me-RIP) and dual-luciferase studied miR-21-5p/FDX1. Mice xenografts showed METTL3's tumorigenic effect. Results: METTL3, with high expression but low methylation in NSCLC, influenced cell behaviors. Its suppression reduced oncogenic properties. METTL3 enhanced miR-21-5p maturation, targeting FDX1 and boosting NSCLC tumorigenicity in mice. Conclusion: METTL3 may promote NSCLC development by facilitating pri-miR-21-5p maturation, upregulating miR-21-5p and targeting inhibition of FDX1.
We investigated a protein called METTL3, which is overly active in lung cancer cells, and how it affects the function of other small molecules. We discovered that as the activity of METTL3 increases, the growth and mobility of lung cancer cells also enhance, potentially accelerating the progression of lung cancer. Through a series of experiments, we observed how METTL3 interacts with other small molecules and further influences the behavior of lung cancer cells. This study helps us understand the role of METTL3 in the development of lung cancer and may offer new strategies for future treatments.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , Ferredoxinas , Neoplasias Pulmonares , MicroRNAs , Animais , Humanos , Camundongos , Carcinoma Pulmonar de Células não Pequenas/genética , Linhagem Celular Tumoral , Proliferação de Células , Cobre , Ferredoxinas/metabolismo , Neoplasias Pulmonares/genética , Metiltransferases/genética , MicroRNAs/genéticaRESUMO
Photosynthesis is a fundamental biogeochemical process, thought to be restricted to a few bacterial and eukaryotic phyla. However, understanding the origin and evolution of phototrophic organisms can be impeded and biased by the difficulties of cultivation. Here, we analyzed metagenomic datasets and found potential photosynthetic abilities encoded in the genomes of uncultivated bacteria within the phylum Myxococcota. A putative photosynthesis gene cluster encoding a type-II reaction center appears in at least six Myxococcota families from three classes, suggesting vertical inheritance of these genes from an early common ancestor, with multiple independent losses in other lineages. Analysis of metatranscriptomic datasets indicate that the putative myxococcotal photosynthesis genes are actively expressed in various natural environments. Furthermore, heterologous expression of myxococcotal pigment biosynthesis genes in a purple bacterium supports that the genes can drive photosynthetic processes. Given that predatory abilities are thought to be widespread across Myxococcota, our results suggest the intriguing possibility of a chimeric lifestyle (combining predatory and photosynthetic abilities) in members of this phylum.
Assuntos
Bactérias , Fotossíntese , Humanos , Filogenia , Bactérias/genética , Fotossíntese/genética , Família MultigênicaRESUMO
An asymmetric wound dressing acts as a skin-like structure serves as a protective barrier between a wound and its surroundings. It allows for the absorption of tissue fluids and the release of active substances at the wound site, thus speeding up the healing process. However, the production of such wound dressings requires the acquisition of specialized tools, expensive polymers, and solvents that contain harmful byproducts. In this study, an asymmetric bacterial cellulose (ABC) wound dressing using starch as a porogen has been developed. By incorporating silver-metal organic frameworks (Ag-MOF) and curcumin into the ABC membrane, the wound dressing gains antioxidant, reactive oxygen species (ROS) scavenging, and anti-bacterial activities. Compared to BC-based wound dressings, this dressing promotes efficient dissolution and controlled release of curcumin and silver ions. In a full-thickness skin defect model, wound dressing not only inhibits the growth of bacteria on infected wounds but also regulates the release of curcumin to reduce inflammation and promote the production of epithelium, blood vessels, and collagen. Consequently, this dressing provides superior wound treatment compared to BC-based dressing.
Assuntos
Curcumina , Prata , Prata/química , Curcumina/farmacologia , Curcumina/química , Antibacterianos/farmacologia , Antibacterianos/química , Cicatrização , Celulose/química , Anti-Inflamatórios/farmacologiaRESUMO
Bathyarchaeia, as one of the most abundant microorganisms on Earth, play vital roles in the global carbon cycle. However, our understanding of their origin, evolution, and ecological functions remains poorly constrained. Here, we present the largest dataset of Bathyarchaeia metagenome assembled genome to date and reclassify Bathyarchaeia into eight order-level units corresponding to the former subgroup system. Highly diversified and versatile carbon metabolisms were found among different orders, particularly atypical C1 metabolic pathways, indicating that Bathyarchaeia represent overlooked important methylotrophs. Molecular dating results indicate that Bathyarchaeia diverged at ~3.3 billion years, followed by three major diversifications at ~3.0, ~2.5, and ~1.8 to 1.7 billion years, likely driven by continental emergence, growth, and intensive submarine volcanism, respectively. The lignin-degrading Bathyarchaeia clade emerged at ~300 million years perhaps contributed to the sharply decreased carbon sequestration rate during the Late Carboniferous period. The evolutionary history of Bathyarchaeia potentially has been shaped by geological forces, which, in turn, affected Earth's surface environment.
Assuntos
Carbono , Redes e Vias Metabólicas , Carbono/metabolismoRESUMO
A novel member of class Alphaproteobacteria was isolated from marine sediment of the South China Sea. Cells of strain LMO-2T were Gram-stain negative, greyish in colour, motile, with a single lateral flagellum and short rod in shape with a slight curve. Strain LMO-2T was positive for oxidase and negative for catalase. The bacterium grew aerobically at 10-40 °C (optimum, 25-30 °C), pH 5.5-10.0 (optimum, pH 7.0) and 0-9â% NaCl (w/v; optimum, 2-3â%). Phylogenetic analysis of the 16S rRNA gene sequence and phylogenomic analysis of the whole genome sequence indicated that strain LMO-2T represents a new genus and a new species within the family Devosiaceae, class Alphaproteobacteria, phylum Pseudomonadota. Comparisons of the 16S rRNA gene sequences of strain LMO-2T showed 94.8â% similarity to its closest relative. The genome size is ~3.45 Mbp with a DNA G+C content of 58.17âmol%. The strain possesses potential capability for the degradation of complex organic matter, i.e. fatty acid and benzoate. The predominant cellular fatty acids (>10â%) were C16â:â0 and C18â:â1 ω7c 11-methyl. The sole respiratory quinone was ubiquinone-10. The major identified polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phospholipid. Based on the polyphasic taxonomic data, strain LMO-2T represents a novel genus and a novel species for which the name Mariluticola halotolerans gen. nov., sp. nov., was proposed in the family Devosiaceae. The type strain is LMO-2T (=CGMCC 1.19273T=JCM 34934T).
Assuntos
Alphaproteobacteria , Ácidos Graxos , Ácidos Graxos/química , Água do Mar/microbiologia , Filogenia , RNA Ribossômico 16S/genética , Composição de Bases , DNA Bacteriano/genética , Técnicas de Tipagem Bacteriana , Análise de Sequência de DNA , Fosfolipídeos/química , ChinaRESUMO
BACKGROUND: A large proportion of prokaryotic microbes in marine sediments remains uncultured, hindering our understanding of their ecological functions and metabolic features. Recent environmental metagenomic studies suggested that many of these uncultured microbes contribute to the degradation of organic matter, accompanied by acetogenesis, but the supporting experimental evidence is limited. RESULTS: Estuarine sediments were incubated with different types of organic matters under anaerobic conditions, and the increase of uncultured bacterial populations was monitored. We found that (1) lignin stimulated the increase of uncultured bacteria within the class Dehalococcoidia. Their ability to metabolize lignin was further supported by the presence of genes associated with a nearly complete degradation pathway of phenolic monomers in the Dehalococcoidia metagenome-assembled genomes (MAGs). (2) The addition of cellulose stimulated the increase of bacteria in the phylum Ca. Fermentibacterota and family Fibrobacterales, a high copy number of genes encoding extracellular endoglucanase or/and 1,4-beta-cellobiosidase for cellulose decomposition and multiple sugar transporters were present in their MAGs. (3) Uncultured lineages in the order Bacteroidales and the family Leptospiraceae were enriched by the addition of casein and oleic acid, respectively, a high copy number of genes encoding extracellular peptidases, and the complete ß-oxidation pathway were found in those MAGs of Bacteroidales and Leptospiraceae, respectively. (4) The growth of unclassified bacteria of the order Clostridiales was found after the addition of both casein and cellulose. Their MAGs contained multiple copies of genes for extracellular peptidases and endoglucanase. Additionally, 13C-labeled acetate was produced in the incubations when 13C-labeled dissolved inorganic carbon was provided. CONCLUSIONS: Our results provide new insights into the roles of microorganisms during organic carbon degradation in anaerobic estuarine sediments and suggest that these macro and single molecular organic carbons support the persistence and increase of uncultivated bacteria. Acetogenesis is an additional important microbial process alongside organic carbon degradation. Video Abstract.
Assuntos
Carbono , Celulase , Carbono/metabolismo , Lignina/metabolismo , Anaerobiose , Caseínas/genética , Caseínas/metabolismo , Celulase/genética , Celulase/metabolismo , Bactérias/genética , Bactérias/metabolismo , Peptídeo Hidrolases/genética , Sedimentos Geológicos/microbiologia , FilogeniaRESUMO
BACKGROUND: No studies have been published on the correlation between lactic dehydrogenase-to-albumin ratio (LAR) and poor prognosis of acute kidney injury (AKI) patients, warranting further research. This analysis sought to investigate the prognostic implication of LAR in critically ill patients with AKI. METHODS: The present study enrolled 11,046 and 5180 adults with AKI from the Medical Information Mart for Intensive Care III (MIMIC III) and MIMIC IV, respectively. Data from MIMIC IV were identified as the training cohort, and those from MIMIC III were identified as the validation cohort. We applied multivariate regression analysis to identify the link between LAR and all-cause mortality. Restricted cubic spline (RCS) was conducted to figure out the correlation between LAR and in-hospital mortality. Furthermore, we carried out stratification analyses to examine if the effects of LAR on in-hospital mortality were consistent across various subclasses. RESULTS: The level of LAR was remarkably higher in the in-hospital non-survivor group (p < 0.001). Furthermore, the increased LAR group presented a remarkably higher rate of in-hospital mortality at AKI stages 1, 2, and 3 compared with the decreased LAR group (all p < 0.001). Multivariate regression analyses exhibited the independent prognostic significance of LAR for all-cause mortality (all p < 0.001). MIMIC III observed concordant results. RCS indicated a non-linear correlation between LAR and in-hospital death (P for non-linearity < 0.001). The relationship between LAR and in-hospital mortality was still significant in patients with various subclasses. CONCLUSIONS: Elevated LAR at admission is a prognostic risk factor for critically ill patients with AKI.
Assuntos
Injúria Renal Aguda , Estado Terminal , Adulto , Humanos , Prognóstico , Mortalidade Hospitalar , Albuminas , Injúria Renal Aguda/diagnóstico , Oxirredutases , Estudos RetrospectivosRESUMO
Marine cold seeps are unique chemosynthetic habitats fuelled by deeply sourced hydrocarbon-rich fluids discharged at the seafloor. Through oxidizing methane and other hydrocarbons, microorganisms inhabiting cold seeps supply subsurface-derived energy to higher trophic levels, sustaining highly productive oases of life in the deep sea. Despite the central role of microbiota in mediating biogeochemical cycles, the factors that govern the assembly and network of prokaryotic communities in cold seeps remain poorly understood. Here we analysed the geochemical and microbiological profiles of 11 different sediment cores from two spatially distant cold seeps of the South China Sea. We show that prokaryotic communities belonging to the same methane-supply regimes (high-methane-supply, low-methane-supply and non-seep control sediments) had a highly similar community structure, regardless of geographical location, seep-associated biota (mussel, clam, microbial mat) and sediment depth. Methane supply appeared to drive the niche partitioning of anaerobic methanotrophic archaea (ANME) at the regional scale, with ANME-1 accounting for >60% sequence abundance of ANME in the high-methane-supply sediments, while ANME-2 dominated (>90%) the low-methane-supply sediments. Increasing methane supply enhanced the contribution of environmental selection but lessened the contributions of dispersal limitation and drift to overall community assembly. High methane supply, moreover, promoted a more tightly connected, less stable prokaryotic network dominated by positive correlations. Together, these results provide a potentially new framework for understanding the niches and network interplay of prokaryotic communities across different methane seepage regimes in cold-seep sediments.