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Scientific Reports Jun 2023This study investigated the effects of 67 species of macroalgae on methanogenesis and rumen fermentation in vitro. Specimens were analyzed for their effect on ruminal...
This study investigated the effects of 67 species of macroalgae on methanogenesis and rumen fermentation in vitro. Specimens were analyzed for their effect on ruminal fermentation and microbial community profiles. Incubations were carried out in an automated gas production system for 24-h and macroalgae were tested at 2% (feed dry matter basis) inclusion rate. Methane yield was decreased 99% by Asparagopsis taxiformis (AT) when compared with the control. Colpomenia peregrina also decreased methane yield 14% compared with control; no other species influenced methane yield. Total gas production was decreased 14 and 10% by AT and Sargassum horneri compared with control, respectively. Total volatile fatty acid (VFA) concentration was decreased between 5 and 8% by 3 macroalgae, whereas AT reduced it by 10%. Molar proportion of acetate was decreased 9% by AT, along with an increase in propionate by 14%. Asparagopsis taxiformis also increased butyrate and valerate molar proportions by 7 and 24%, respectively, whereas 3 macroalgae species decreased molar proportion of butyrate 3 to 5%. Vertebrata lanosa increased ammonia concentration, whereas 3 other species decreased it. Inclusion of AT decreased relative abundance of Prevotella, Bacteroidales, Firmicutes and Methanobacteriaceae, whereas Clostridium, Anaerovibrio and Methanobrevibacter were increased. Specific gene activities for Methanosphaera stadtmane and Methanobrevibacter ruminantium were decreased by AT inclusion. In this in vitro study, Asparagopsis taxiformis was most effective in decreasing methane concentration and yield, but also decreased total gas production and VFA concentration which indicates overall inhibition of ruminal fermentation. No other macroalgae were identified as potential mitigants of enteric methane.
Topics: Animals; Seaweed; Methane; Rumen; Fatty Acids, Volatile; Butyrates; Fermentation; Diet; Animal Feed; Digestion
PubMed: 37330586
DOI: 10.1038/s41598-023-36359-y -
Frontiers in Microbiology 2023Some observational studies have shown that immune thrombocytopenia (ITP) is highly associated with the alteration-composition of gut microbiota. However, the causality...
BACKGROUND
Some observational studies have shown that immune thrombocytopenia (ITP) is highly associated with the alteration-composition of gut microbiota. However, the causality of gut microbiota on ITP has not yet been determined.
METHODS
Based on accessible summary statistics of the genome-wide union, the latent connection between ITP and gut microbiota was estimated using bi-directional Mendelian randomization (MR) and multivariable MR (MVMR) analyses. Inverse variance weighted (IVW), weighted median analyses, and MR-Egger regression methods were performed to examine the causal correlation between ITP and the gut microbiota. Several sensitivity analyses verified the MR results. The strength of causal relationships was evaluated using the MR-Steiger test. MVMR analysis was undertaken to test the independent causal effect. MR analyses of reverse direction were made to exclude the potential of reverse correlations. Finally, GO enrichment analyses were carried out to explore the biological functions.
RESULTS
After FDR adjustment, two microbial taxa were identified to be causally associated with ITP ( < 0.10), namely ( = 7.31 × 10) and ( = 7.31 × 10). In addition, eight microbial taxa were considered as potentially causal features under the nominal significance ( < 0.05): , , , , , , , and . According to the reverse-direction MR study findings, the gut microbiota was not significantly affected by ITP. There was no discernible horizontal pleiotropy or instrument heterogeneity. Finally, GO enrichment analyses showed how the identified microbial taxa participate in ITP through their underlying biological mechanisms.
CONCLUSION
Several microbial taxa were discovered to be causally linked to ITP in this MR investigation. The findings improve our understanding of the gut microbiome in the risk of ITP.
PubMed: 38075905
DOI: 10.3389/fmicb.2023.1190866 -
Journal of Translational Medicine Feb 2023Gut dysbacteriosis has been reported as one of the etiologies for irritable bowel syndrome (IBS). However, the association between gut microbiota and IBS is still...
BACKGROUND
Gut dysbacteriosis has been reported as one of the etiologies for irritable bowel syndrome (IBS). However, the association between gut microbiota and IBS is still inconclusive.
METHOD
A paired-sample study was designed by retrieving original multicenter 16 s-rRNA data of IBS patients and healthy controls from the GMrepo database. The propensity score matching (PSM) algorithm was applied to reduce confounding bias. The differential analysis of microbiota composition was performed at different taxonomic levels. The co-occurrence network was established. Subgroup analysis was performed to identify specific microbial compositions in different IBS subtypes.
RESULTS
A total of 1522 amplicon samples were initially enrolled. After PSM, 708 individuals (354 IBS and 354 healthy controls) were eligible for further analysis. A total of 1,160 genera were identified. We identified significantly changed taxa in IBS groups (IBS-enriched: the families Enterobacteriaceae, Moraxellaceae and Sphingobacteriaceae; the genera Streptococcus, Bacillus, Enterocloster, Sphingobacterium, Holdemania and Acinetobacter. IBS-depleted: the phyla Firmicutes, Euryarchaeota, Cyanobacteria, Acidobacteria and Lentisphaerae; the families Bifidobacteriaceae, Ruminococcaceae, Methanobacteriaceae and the other 25 families; the genera Faecalibacterium, Bifidobacterium and other 68 genera). The co-occurrence network identified three hub genera and six hub species (including Faecalibacterium prausnitzii) that may be involved in IBS pathophysiology. Strong positive interactions were identified among the Bifidobacterium longum, Bifidobacterium breve and Bifidobacterium adolescentis in the Bifidobacterium community.
CONCLUSION
This study provides quantitative analysis and visualization of the interaction between the gut microbiota and IBS. The identification of key species should be further validated to evaluate their causal relationships with the pathogenesis of IBS.
Topics: Humans; Irritable Bowel Syndrome; Gastrointestinal Microbiome; Bacteria; RNA, Ribosomal, 16S; Feces
PubMed: 36774467
DOI: 10.1186/s12967-023-03953-7 -
International Journal of Molecular... May 2020The microbial cell membrane is affected by physicochemical parameters, such as temperature and pH, but also by the specific growth rate of the host organism.... (Review)
Review
The microbial cell membrane is affected by physicochemical parameters, such as temperature and pH, but also by the specific growth rate of the host organism. Homeoviscous adaption describes the process of maintaining membrane fluidity and permeability throughout these environmental changes. Archaea, and thereby, spp. exhibit a unique lipid composition of ether lipids, which are altered in regard to the ratio of diether to tetraether lipids, number of cyclopentane rings and type of head groups, as a coping mechanism against environmental changes. The main biotechnological application of the membrane lipids of spp. are so called archaeosomes. Archaeosomes are liposomes which are fully or partly generated from archaeal lipids and harbor the potential to be used as drug delivery systems for vaccines, proteins, peptides and nucleic acids. This review summarizes the influence of environmental parameters on the cell membrane of spp. and the biotechnological applications of their membrane lipids.
Topics: Biotechnology; Cell Membrane; Cyclopentanes; Drug Delivery Systems; Hydrogen-Ion Concentration; Liposomes; Membrane Lipids; Membranes, Artificial; Methanobacterium; Natronococcus; Peptides; Sulfolobus; Temperature; Viscosity
PubMed: 32486295
DOI: 10.3390/ijms21113935 -
Journal of Dairy Science Jul 2024The intestinal microbiota plays a pivotal role in digestive processes and maintains gut health and intestinal homeostasis. These functions may be compromised by...
Heat stress and feeding effects on the mucosa-associated and digesta microbiome and their relationship to plasma and digesta fluid metabolites in the jejunum of dairy cows.
The intestinal microbiota plays a pivotal role in digestive processes and maintains gut health and intestinal homeostasis. These functions may be compromised by increased environmental heat, which in turn reduces feed intake and gut integrity and activates the intestinal immune system. It remains unknown whether high ambient temperatures, which cause heat stress (HS) in dairy cows, disturb the eubiosis of the microbial community, and if so, to which extent the reduction in feed intake and the impairment of circulating and intestinal metabolites account for the alterations of the jejunal microbiota. To address these questions, jejunal digesta, mucosa, and plasma samples were collected from cows exposed to heat stress (HS; 28°C, temperature-humidity index [THI] = 76, n = 10), control conditions (CON; 16°C, THI = 60, n = 10), or pair-fed (PF; 16°C, THI = 60, n = 10) for 7 d. Digesta fluids were examined for pH, acetate, nonesterified fatty acids (NEFA), glucose, and lactate, and plasma samples were analyzed for glucose, lactate, BHB, triglycerides, NEFA, creatinine, and urea. The microbiota of the digesta and mucosa samples were analyzed by 16S rRNA sequencing. The α-diversity was higher in mucosa than digesta but was not affected by high ambient temperatures. However, the mucosa-associated microbiota appeared more responsive to ambient heat than the digesta microbiome. The adaptive responses under HS conditions comprised an increased mucosal abundance of Bifidobacteriaceae, Succinivibrionaceae UCG-001, Clostridia and Lactobacillus. In the digesta, HS has exerted effects on microbial abundance of Colidextribacter, and Lachnospiraceae UCG-008. Several correlations between plasma or intestinal metabolites and microbiota were elucidated, including Methanobacteriaceae correlating positively with plasma BHB and digesta glucose concentrations. Moreover, the reduction in feed intake during HS had non-negligible effects on microbial diversity and the abundance of certain taxa, underpinning the importance of nutrient supply on maintaining intestinal homeostasis.
Topics: Animals; Cattle; Female; Jejunum; Gastrointestinal Microbiome; Hot Temperature; Microbiota
PubMed: 38431250
DOI: 10.3168/jds.2023-24242 -
Animal : An International Journal of... Jan 2021The greenhouse gases (GHGs) derived from agriculture include carbon dioxide, nitrous oxide, and methane (CH). Of these GHGs, CH, in particular, constitutes a major... (Review)
Review
The greenhouse gases (GHGs) derived from agriculture include carbon dioxide, nitrous oxide, and methane (CH). Of these GHGs, CH, in particular, constitutes a major component of the GHG emitted by the agricultural sector. Along with environmental concerns, CH emission also leads to losses in gross energy intake with economic implications. While ruminants are considered the main source of CH from agriculture, nonruminant animals also contribute substantially, and the CH emission intensity of nonruminants remains comparable to that of ruminants. Means of mitigating CH emissions from enteric fermentation have therefore been sought. Methane is produced by methanogens-archaeal microorganisms that inhabit the digestive tracts of animals and participate in fermentation processes. As the diversity of methanogen communities is thought to be responsible for the differences in CH production among nonruminant animals, it is necessary to investigate the archaeal composition of specific animal species. Methanogens play an important role in energy metabolism and adipose tissue deposition in animals. Higher abundances of methanogens, along with their higher diversity, have been reported to contribute to lean phenotype in pigs. In particular, a greater abundance of Methanosphaera spp. and early dominance of Methanobrevibacter smithii have been reported to correlate with lower body fat formation in pigs. Besides the contribution of methanogens to the metabolic phenotype of their hosts, CH release reduces the productivity that could be achieved through other hydrogen (H) disposal pathways. Enhanced participation of acetogenesis in H disposal, leading to acetate formation, could be a more favorable direction for animal production and the environment. Better knowledge and understanding of the archaeal communities of the gastrointestinal tract (GIT), including their metabolism and interactions with other microorganisms, would thus allow the development of new strategies for inhibiting methanogens and shifting toward acetogenesis. There are a variety of approaches to inhibiting methanogens and mitigating methanogenesis in ruminants, which can find an application for nonruminants, such as nutritional changes through supplementation with biologically active compounds and management changes. We summarize the available reports and provide a comprehensive review of methanogens living in the GIT of various nonruminants, such as swine, horses, donkeys, rabbits, and poultry. This review will help in a better understanding of the populations and diversity of methanogens and the implications of their presence in nonruminant animals.
Topics: Animals; Animals, Domestic; Horses; Methane; Methanobrevibacter; Rabbits; Rumen; Ruminants; Swine
PubMed: 33516013
DOI: 10.1016/j.animal.2020.100060 -
Scientific Reports Jun 2018Methanogens have already been described in periodontitis but not in peri-implantitis. Thirty peri-implantitis samples and 28 control samples were collected in 28...
Methanogens have already been described in periodontitis but not in peri-implantitis. Thirty peri-implantitis samples and 28 control samples were collected in 28 consenting peri-implantitis patients. PCR-sequencing of the 16S rRNA gene was used as a broad-spectrum screening method and results were further confirmed by real-time quantitative PCR targeting the mcrA genes. Results showed a methanogen community dominated by Methanobrevibacter oralis in 31/58 (51%) samples including 16/28 (57%) control samples and 15/30 (50%) peri-implantitis samples. Methanobrevibacter massiliense was detected in 5/58 (8.6%) samples including 3/28 (1%) control samples and 2/30 (6.7%) peri-implantitis samples. The prevalence of M. oralis or M. massiliense did not significantly differ in peri-implantitis and control samples (exact Fisher test, P = 0.61 and P = 0.67, respectively). Further ponderation of the methanogen load by the real-time quantitative PCR for actin human gene again indicated non-significant difference (Wilcoxon-Mann-Whitney test, P = 0.48 and P = 0.40, respectively). These data show that the prevalence of methanogens does not differ in peri-implantitis lesions and healthy sites, when individuals are their own control. These data do not allow assigning a specific pathogenic role to methanogens in peri-implantitis; methanogens rather are part of the commensal and normal flora of the oral cavity.
Topics: Adult; Aged; Aged, 80 and over; Female; Humans; Male; Methanobrevibacter; Microbiota; Middle Aged; Peri-Implantitis
PubMed: 29930395
DOI: 10.1038/s41598-018-27862-8 -
Microbiology Spectrum Jun 2022Trophic interactions between microbes are postulated to determine whether a host microbiome is healthy or causes predisposition to disease. Two abundant taxa, the...
Trophic interactions between microbes are postulated to determine whether a host microbiome is healthy or causes predisposition to disease. Two abundant taxa, the Gram-negative heterotrophic bacterium Bacteroides thetaiotaomicron and the methanogenic archaeon Methanobrevibacter smithii, are proposed to have a synergistic metabolic relationship. Both organisms play vital roles in human gut health; B. thetaiotaomicron assists the host by fermenting dietary polysaccharides, whereas M. smithii consumes end-stage fermentation products and is hypothesized to relieve feedback inhibition of upstream microbes such as B. thetaiotaomicron. To study their metabolic interactions, we defined and optimized a coculture system and used software testing techniques to analyze growth under a range of conditions representing the nutrient environment of the host. We verify that B. thetaiotaomicron fermentation products are sufficient for M. smithii growth and that accumulation of fermentation products alters secretion of metabolites by B. thetaiotaomicron to benefit M. smithii. Studies suggest that B. thetaiotaomicron metabolic efficiency is greater in the absence of fermentation products or in the presence of M. smithii. Under certain conditions, B. thetaiotaomicron and M. smithii form interspecies granules consistent with behavior observed for syntrophic partnerships between microbes in soil or sediment enrichments and anaerobic digesters. Furthermore, when vitamin B, hematin, and hydrogen gas are abundant, coculture growth is greater than the sum of growth observed for monocultures, suggesting that both organisms benefit from a synergistic mutual metabolic relationship. The human gut functions through a complex system of interactions between the host human tissue and the microbes which inhabit it. These diverse interactions are difficult to model or examine under controlled laboratory conditions. We studied the interactions between two dominant human gut microbes, B. thetaiotaomicron and M. smithii, using a seven-component culturing approach that allows the systematic examination of the metabolic complexity of this binary microbial system. By combining high-throughput methods with machine learning techniques, we were able to investigate the interactions between two dominant genera of the gut microbiome in a wide variety of environmental conditions. Our approach can be broadly applied to studying microbial interactions and may be extended to evaluate and curate computational metabolic models. The software tools developed for this study are available as user-friendly tutorials in the Department of Energy KBase.
Topics: Bacteroides; Fermentation; Gastrointestinal Microbiome; Humans; Methanobrevibacter; Microbial Interactions
PubMed: 35536023
DOI: 10.1128/spectrum.01067-22 -
NPJ Biofilms and Microbiomes Sep 2022A meta-analysis approach was used, to study the microbiomes of biofilms and planktonic communities underpinning microbial electrosynthesis (MES) cells. High-throughput... (Meta-Analysis)
Meta-Analysis
A meta-analysis approach was used, to study the microbiomes of biofilms and planktonic communities underpinning microbial electrosynthesis (MES) cells. High-throughput DNA sequencing of 16S rRNA gene amplicons has been increasingly applied to understand MES systems. In this meta-analysis of 22 studies, we find that acetogenic and methanogenic MES cells share 80% of a cathodic core microbiome, and that different inoculum pre-treatments strongly affect community composition. Oxygen scavengers were more abundant in planktonic communities, and several key organisms were associated with operating parameters and good cell performance. We suggest Desulfovibrio sp. play a role in initiating early biofilm development and shaping microbial communities by catalysing H production, to sustain either Acetobacterium sp. or Methanobacterium sp. Microbial community assembly became more stochastic over time, causing diversification of the biofilm (cathodic) community in acetogenic cells and leading to re-establishment of methanogens, despite inoculum pre-treatments. This suggests that repeated interventions may be required to suppress methanogenesis.
Topics: Methane; Methanobacterium; Microbiota; Oxygen; RNA, Ribosomal, 16S
PubMed: 36138044
DOI: 10.1038/s41522-022-00337-5 -
Dermatology and Therapy Mar 2024Observational studies and clinical trials have supported the association between gut microbiota and psoriatic arthritis. However, the causal link between gut microbiota...
INTRODUCTION
Observational studies and clinical trials have supported the association between gut microbiota and psoriatic arthritis. However, the causal link between gut microbiota and psoriatic arthritis is still unclear.
METHODS
A two-sample bi-directional Mendelian randomization analysis was performed using the summary statistics of gut microbiota from the largest available genome-wide association study meta-analysis (n = 13,266) conducted by the MiBioGen consortium. The summary statistics of psoriatic arthritis were extracted directly from the FinnGen consortium, which consists of 3186 psoriatic arthritis patients and 24,086 controls. Sensitivity analyses were conducted to assess the validity of our findings. Enrichment analyses were used to investigate the biofunction and pathways.
RESULTS
Inverse variance weighted (IVW) estimates suggested that family Rikenellaceae (P = 0.032) and genus Ruminococcaceae UCG011 (P = 0.014) had a detrimental effect on psoriatic arthritis. We also noticed the negative association between the class Methanobacteria (P = 0.032), order Methanobacteriales (P = 0.032), family Methanobacteriaceae (P = 0.032), genus Eubacterium fissicatena group (P = 0.010), genus Methanobrevibacter (P = 0.031), and genus Butyricicoccus (P = 0.041) with psoriatic arthritis. Sensitivity analyses showed that genus Butyricicoccus had pleiotropy and heterogeneity. According to the results of reverse MR analysis, the causal effect of psoriatic arthritis was found on six taxa, respectivelyc family Clostridiaceae1, family Defluviitaleaceae, genus Butyrivibrio, genus Defluviitaleaceae UCG011, genus Clostridium sensu stricto1, and genus Ruminococcaceae UCG011.
CONCLUSION
This two-sample bidirectional Mendelian randomization analysis suggested that the gut microbiota had a causal effect on psoriatic arthritis and implied the potential role of probiotics in the management and prevention of psoriatic arthritis.
PubMed: 38451424
DOI: 10.1007/s13555-024-01121-3