Unravelling lactate-acetate and sugar conversion into butyrate by intestinal Anaerobutyricum and Anaerostipes species by comparative proteogenomics

Thed- andl-forms of lactate are important fermentation metabolites produced by intestinal bacteria but are found to negatively affect mucosal barrier function and human health. Both enantiomers of lactate can be converted with acetate into the presumed beneficial butyrate by a phylogenetically related group of anaerobes, includingAnaerobutyricumandAnaerostipesspp. This is a low energy yielding process with a partially unknown pathway inAnaerobutyricumandAnaerostipesspp. and hence, we sought to address this via a comparative genomics, proteomics and physiology approach. We compared growth ofAnaerobutyricum soehngeniion lactate with that on sucrose and sorbitol. Comparative proteomics revealed complete pathway of butyrate formation from sucrose, sorbitol and lactate. Notably, a gene cluster,lctABCDEFwas abundantly expressed when grown on lactate. This gene cluster encodes a lactate dehydrogenase (lctD), electron transport proteins A and B (lctCB), nickel-dependent racemase (lctE), lactate permease (lctF) and short-chain acyl-CoA dehydrogenase (lctG). Investigation of available genomes of intestinal bacteria revealed this new gene cluster to be highly conserved in onlyAnaerobutyricumandAnaerostipesspp. Present study demonstrates thatA. soehngeniiand several relatedAnaerobutyricumandAnaerostipesspp. are highly adapted for a lifestyle involving lactate plus acetate utilization in the human intestinal tract.Peer reviewe

Comparative genomics and proteomics of Eubacterium maltosivorans : functional identification of trimethylamine methyltransferases and bacterial microcompartments in a human intestinal bacterium with a versatile lifestyle

Eubacterium maltosivorans YIT is a human intestinal isolate capable of acetogenic, propionogenic and butyrogenic growth. Its 4.3-Mb genome sequence contains coding sequences for 4227 proteins, including 41 different methyltransferases. Comparative proteomics of strain YIT showed the Wood-Ljungdahl pathway proteins to be actively produced during homoacetogenic growth on H-2 and CO2 while butyrogenic growth on a mixture of lactate and acetate significantly upregulated the production of proteins encoded by the recently identified lctABCDEF cluster and accessory proteins. Growth on H-2 and CO2 unexpectedly induced the production of two related trimethylamine methyltransferases. Moreover, a set of 16 different trimethylamine methyltransferases together with proteins for bacterial microcompartments were produced during growth and deamination of the quaternary amines, betaine, carnitine and choline. Growth of strain YIT on 1,2-propanediol generated propionate with propanol and induced the formation of bacterial microcompartments that were also prominently visible in betaine-grown cells. The present study demonstrates that E. maltosivorans is highly versatile in converting low-energy fermentation end-products in the human gut into butyrate and propionate whilst being capable of preventing the formation of the undesired trimethylamine by converting betaine and other quaternary amines in bacterial microcompartments into acetate and butyrate.Peer reviewe

Intestinimonas-like bacteria are important butyrate producers that utilize Nε-fructosyllysine and lysine in formula-fed infants and adults

Our study aim is to investigate the role of Intestinimonas, Nε-fructosyllysine (FL)-degrading bacterium, in infants and adults. We used lysine and subsequently FL in anaerobic serial dilutions of stools of infants and adults to enrich lysine and FL-degrading species. The fecal microbiota of adults were able to ferment lysine and FL to butyrate. Different groups of Intestinimonas spp. were detected from all lysine enrichments whereas the FL enrichments consisted of broader taxonomic groups with a reduced abundance of Intestinimonas-related species. Remarkably, the capability to degrade FL was only observed in formula-fed but not in breast-fed infants, which may relate to high contents of FL in formulas after thermal treatment. This possibility was supported by analyzing metagenomic datasets of 3-month and 4-month infants. Our data indicate the key role of Intestinimonas-like bacteria in FL degradation in formula-fed infants and adults as a profound example of adaptation of intestinal bacteria to dietary components.Peer reviewe

Climate Change Impacts, Vulnerability Assessment and Economic Analysis of Adaptation Strategies in Ben Tre Province, Vietnam

Scientific database has proven that Vietnam is one of the most affected countries due to climate change impacts on aquaculture and economies of rural communities. Ben Tre region has suffered immensely from recent salt water intrusion. Climate change generates sea level rise, increase in temperature and salt water intrusion. In 2005 losses had increased to US$37 million. We conducted three focus group discussions (FGDs) to assist in the identification of vulnerable sectors and households and community adaptation strategies to climate change. Households were also evaluated based on the levels of vulnerability. Residents have requested the construction of a water treatment plant and a dike system. CEA is employed as the tool for evaluating the two planned adaptations: Building a freshwater-supplying factory and Building a sea dike system. Total costs include initial investment and annual operating costs. We also conducted a benefit cost analysis since the outcomes of the strategies are different. The distribution of vulnerability index showed that 31% of households are highly vulnerable to climatic risk while 56% of households are not vulnerable at all. The sea dike is three times more expensive than the freshwater plant. In addition to the higher investment, it is more costly to keep the sea dike under operation annually. The water treatment plant is more cost effective in servicing the communities with freshwater but the dike has a higher benefit cost ratio when all costs are internalized and secondary benefits to agriculture and aquaculture are considered.EEPSEA and WorldFish Cente

Climate Change Awareness and Impacts on Aquaculture in Poor Rural Coastal Communities, Ben Tre Province, Vietnam

Vietnam has been ranked as one of the countries in Asia with the highest vulnerabilities to climate change impacts on fisheries and aquaculture. Eight of those ten provinces are located in the Mekong River Delta, including Ben Tre Province. We conducted a study to identify the impacts of climate change events on Ben Tre province poor rural coastal communities, to evaluate their awareness and the effects of climate change events on aquaculture. Farmers were aware of changing climatic conditions and pointed out indicators of these changes: (1) Changes in production and culturing patterns, (2) Changes in housing designs, (3) Improvement in drinking water collection and increase in water procurement, (4) Pumping of fresh water in the shrimp ponds, and (5) Building of dikes to prevent salt water intrusion. About 90 percent of respondents indicated that they suffered losses from salt water intrusion. Total losses generated by salt water intrusion amounted to VND 1,599,803,000, equivalent to USD 77,151. Age, education and previous effects from climate change events affected knowledge and perception of severity of climate change events. Farmers who were engaged in aquaculture were more likely to be prepared for climate change events than those who were not.EEPSEA and WorldFish Cente

Replacement of freshwater small-size fish by formulated feed in snakehead (Channa striata) aquaculture: Experimental and commercial-scale pond trials, with economic analysis

Traditional snakehead culture in Southeast Asia relies on use of small-size (trash) fish as food, an unsustainable practice. Following development of weaning methods and testing of formulated feed (FF) in laboratory experiments, we conducted feeding trials of FF vs. trash fish (TF) in experimental ponds at Can Tho University (CTU), followed by similar trials on commercial farms in two provinces in Vietnam. CTU pond trials consisted of five treatments (in triplicate), in which TF was replaced by FF in increasing percentages: 0 (control), 25, 50, 75, and 100% replacement of TF by FF (i.e., three treatments had mixed TF/FF diets). Although survival was significantly reduced in the 100% replacement treatment, and growth was significantly reduced in the 75% and 100% replacement treatments, the cost per kg of fish produced was 28–35% less in those high-replacement treatments compared to the 0% replacement treatment. On-farm trials were then conducted at two farms in An Giang and Dong Thap provinces for 6 months with snakehead fed TF only or FF only. At both farms, survival (73–80%) was not significantly different, but growth was significantly better on FF diet at both; however, FF-fed fish at the An Giang farm showed significantly higher levels of abnormal development. Overall production was about twice as high at the An Giang farm as at Dong Thap, but significantly greater production by FF-fed fish vs. TF-fed fish was only seen at Dong Thap. Sensory evaluation by a tasting panel found no difference in product quality between FF-fed fish, TF-fed fish, and a commercial sample bought in the market. Economic analysis indicated that profits were higher for FF-fed fish from both farms, although production costs and sales varied greatly, reflecting market differences in the two provinces

Experience in Using Mobile Laboratory for Monitoring and Diagnostics in the Socialist Republic of Vietnam

The aim was to present the experience of using mobile laboratory for monitoring and diagnostics (MLMD) during the epizootiological monitoring of the northern provinces of Vietnam. MLMD was transferred by Federal Service for Surveillance in the Sphere of Consumers Rights Protection and Human Welfare to the Socialist Republic of Vietnam as part of implementation of cooperation programs on combating infectious diseases. The use of MLMD made it possible to obtain new information on the circulation of pathogens of natural-focal infectious diseases on the territory of Vietnam. It also provided the necessary conditions for conducting research using methods of express diagnostics, bacteriological analysis, performing a full cycle of work – from the receipt of samples to the disinfection and destruction of infected material in compliance with the requirements of biological safety in the field. The effectiveness of using mobile laboratories in response to the emergencies of sanitary and epidemiological nature, both to strengthen stationary laboratory bases and to organize diagnostic studies in remote regions, has been shown. The use of MLMD for the diagnosis of COVID‑19 has been an effective component of countering the new coronavirus infection in Vietnam and significantly increased the volume of testing in the country

Conversion of dietary inositol into propionate and acetate by commensal Anaerostipes associates with host health

Here, the authors report an anaerobic metabolic pathway from the dominant gut butyrogen Anaerostipes, showing several strains of this genus to be capable of producing propionate from dietary myo-inositol that associates with reduced fasting-glucose levels in mice. We describe the anaerobic conversion of inositol stereoisomers to propionate and acetate by the abundant intestinal genus Anaerostipes. A inositol pathway was elucidated by nuclear magnetic resonance using [C-13]-inositols, mass spectrometry and proteogenomic analyses in A. rhamnosivorans, identifying 3-oxoacid CoA transferase as a key enzyme involved in both 3-oxopropionyl-CoA and propionate formation. This pathway also allowed conversion of phytate-derived inositol into propionate as shown with [C-13]-phytate in fecal samples amended with A. rhamnosivorans. Metabolic and (meta)genomic analyses explained the adaptation of Anaerostipes spp. to inositol-containing substrates and identified a propionate-production gene cluster to be inversely associated with metabolic biomarkers in (pre)diabetes cohorts. Co-administration of myo-inositol with live A. rhamnosivorans in western-diet fed mice reduced fasting-glucose levels comparing to heat-killed A. rhamnosivorans after 6-weeks treatment. Altogether, these data suggest a potential beneficial role for intestinal Anaerostipes spp. in promoting host health.Peer reviewe