Genus Desulfovibrio Research Articles

Gallstone Disease, Obesity and the Firmicutes/Bacteroidetes Ratio as a Possible Biomarker of Gut Dysbiosis.

Obesity is a major risk factor for developing gallstone disease (GSD). Previous studies have shown that obesity is associated with an elevated Firmicutes/Bacteroidetes ratio in the gut microbiota. These findings suggest that the development of GSD may be related to gut dysbiosis. This review presents and summarizes the recent findings of studies on the gut microbiota in patients with GSD. Most of the studies on the gut microbiota in patients with GSD have shown a significant increase in the phyla Firmicutes (Lactobacillaceae family, genera Clostridium, Ruminococcus, Veillonella, Blautia, Dorea, Anaerostipes, and Oscillospira), Actinobacteria (Bifidobacterium genus), Proteobacteria, Bacteroidetes (genera Bacteroides, Prevotella, and Fusobacterium) and a significant decrease in the phyla Bacteroidetes (family Muribaculaceae, and genera Bacteroides, Prevotella, Alistipes, Paludibacter, Barnesiella), Firmicutes (genera Faecalibacterium, Eubacterium, Lachnospira, and Roseburia), Actinobacteria (Bifidobacterium genus), and Proteobacteria (Desulfovibrio genus). The influence of GSD on microbial diversity is not clear. Some studies report that GSD reduces microbial diversity in the bile, whereas others suggest the increase in microbial diversity in the bile of patients with GSD. The phyla Proteobacteria (especially family Enterobacteriaceae) and Firmicutes (Enterococcus genus) are most commonly detected in the bile of patients with GSD. On the other hand, the composition of bile microbiota in patients with GSD shows considerable inter-individual variability. The impact of GSD on the Firmicutes/Bacteroidetes ratio is unclear and reports are contradictory. For this reason, it should be stated that the results of reviewed studies do not allow for drawing unequivocal conclusions regarding the relationship between GSD and the Firmicutes/Bacteroidetes ratio in the microbiota.

Anaerobic Transformation and Detoxification of Sulfamethoxazole by Sulfate-Reducing Enrichments and Desulfovibrio vulgaris

Sulfamethoxazole (SMX) is a veterinary antibiotic that is not efficiently removed from wastewater by routine treatment and therefore can be detected widely in the environment. Here, we investigated whether microbial anaerobic transformation can contribute to the removal of SMX in constructed systems. We enriched SMX-transforming mixed cultures from sediment of a constructed wetland and from digester sludge of a wastewater treatment plant. Transformation of SMX was observed in both sulfate-reducing and methanogenic cultures, whereas nitrate-reducing cultures showed no SMX transformation. In sulfate-reducing cultures, up to 90% of an initial SMX concentration of 100-250 μM was removed within 6 weeks of incubation, and the experiments demonstrated that the transformation was microbially catalyzed. The transformation products in sulfate-reducing cultures were identified as the reduced and isomerized forms of the isoxazole SMX moiety. The transformation products did not spontaneously reoxidize to SMX after oxygen exposure, and their antibacterial activity was significantly decreased compared to SMX. Population analyses in sequential transfers of the sulfate-reducing cultures revealed a community shift toward the genus Desulfovibrio. We therefore tested a deposited strain of Desulfovibrio vulgaris Hildenborough for its capacity to transform SMX and observed the same transformation products and similar transformation rates as in the enrichment cultures. Our work suggests that an initial anaerobic step in wastewater treatment can reduce the concentration of SMX in effluents and could contribute to decreased SMX concentrations in the environment.

Nuciferine modulates the gut microbiota and prevents obesity in high-fat diet-fed rats

Gut microbiota dysbiosis has a significant role in the pathogenesis of metabolic diseases, including obesity. Nuciferine (NUC) is a main bioactive component in the lotus leaf that has been used as food in China since ancient times. Here, we examined whether the anti-obesity effects of NUC are related to modulations in the gut microbiota. Using an obese rat model fed a HFD for 8 weeks, we show that NUC supplementation of HFD rats prevents weight gain, reduces fat accumulation, and ameliorates lipid metabolic disorders. Furthermore, 16S rRNA gene sequencing of the fecal microbiota suggested that NUC changed the diversity and composition of the gut microbiota in HFD-fed rats. In particular, NUC decreased the ratio of the phyla Firmicutes/Bacteroidetes, the relative abundance of the LPS-producing genus Desulfovibrio and bacteria involved in lipid metabolism, whereas it increased the relative abundance of SCFA-producing bacteria in HFD-fed rats. Predicted functional analysis of microbial communities showed that NUC modified genes involved in LPS biosynthesis and lipid metabolism. In addition, serum metabolomics analysis revealed that NUC effectively improved HFD-induced disorders of endogenous metabolism, especially lipid metabolism. Notably, NUC promoted SCFA production and enhanced intestinal integrity, leading to lower blood endotoxemia to reduce inflammation in HFD-fed rats. Together, the anti-obesity effects of NUC may be related to modulations in the composition and potential function of gut microbiota, improvement in intestinal barrier integrity and prevention of chronic low-grade inflammation. This research may provide support for the application of NUC in the prevention and treatment of obesity.

Combination of Chemical and Biological-Chemical Methods for Elimination of Metals from Acid Mine Drainage

Each acid mine drainage has a specific composition, but always contains sulphuric acid, dissolved heavy metals, sulphates, iron precipitates and their pH can be very low. The elimination of metals form the acid mine drainage is a severe environmental problem andhas been a long-standing major concern to scientists, engineers, industry and governments. Various methods are used for the metalsremoval from waters, but any of them have been applied under commercial-scale conditions. Mostly studied are chemical and biological-chemical methods. Main aim of the paper was to interpret the combination of chemical and biological-chemical methods for theheavy metals elimination from the synthetic solution of acid mine drainage, coming from the zinc mine located in Tùnel Kingsmilloutlet of the Rio Yaulì (district of Yauli – Perù). The metals selective precipitation as hydroxides (chemical method) and sulphides(biological-chemical method) at the various values of pH acid mine drainage is the fundamental of the examined process. For thehydrogen sulphide production the sulphate-reducing bacteria of genus Desulfovibrio was used. The selective sequential precipitationprocess reaches the selective precipitation of chosen metals with 97–99% efficiency – Fe, As, Al and Mn in the form of metal hydroxides,Cu and Zn as metal sulphides

Relationships of sleep disturbance, intestinal microbiota, and postoperative pain in breast cancer patients: a prospective observational study

PurposeOur study was designed to examine the possible relationship between gut microbiota, sleep disturbances, and acute postoperative pain.MethodsUsing 16S rRNA sequencing, we analyzed preoperative fecal samples from women undergoing breast cancer surgery. Preoperative sleep disturbance was evaluated with the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Peak and average pain at rest and movement were evaluated 24 h after surgery, using a numerical rating scale (NRS). Preoperative symptoms of depression and anxiety were assessed with the Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7), respectively. Inflammation was measured using white blood cell and neutrophil counts, together with platelet-lymphocyte ratio, and neutrophil-lymphocyte ratio.ResultsPreoperative sleep disturbance was associated with more severe acute postoperative pain. At the phylum level, women with poor sleep quality had higher relative abundance of Firmicutes (p = 0.021) and lower relative abundance of Bacteroidetes (p = 0.013). At the genus level, women with poor sleep quality harbored higher relative abundance of Acidaminococcus and lower relative abundance of several genera. The genus Alloprevotella was negatively associated with peak pain at movement during the first 24 h (r = − 0.592, p < 0.001). The genus Desulfovibrio was negatively associated with symptoms of anxiety (r = − 0.448, p = 0.006). However, partial correlations suggested that the relationship between Alloprevotella and peak pain at movement during the first 24 h was not statistically significant after controlling for sleep (r = − 0.134, p = 0.443).ConclusionThese findings suggest that the changed gut microbiota may be involved in sleep-pain interaction and could be applied as a potential preventive method for postoperative pain.Trial registrationThe present clinical study has been registered on Chinese Clinical Trial Registry (www.chictr.org.cn); the clinical trial registration number is ChiCTR1900021730; the date of registration is March 7, 2019.

Feasibility of Co-Treating Olive Mill Wastewater and Acid Mine Drainage

Previous tests using a growth medium and olive mill wastewater (OMWW) have shown that it supplies carbon and electron donors suitable for sulphate reducing bacteria (SRB). We assessed the co-treatment of acid mine drainage (AMD) and OMWW using SRB-enriched bioreactors and identified the most abundant bacterial populations present under optimized conditions. The process requires a neutralizing agent to create optimal pH conditions for successful removal of the AMD’s main contaminants. Concentrations of SO42−, Al, Fe, Cu, Zn, and Mn decreased to below Portugal’s maximum admissible values for irrigation waters, and all but Mn were reduced to less than Portugal’s emission limit values (ELVs) for wastewater discharges. Phenol concentrations—the main pollutants in OMWW—dropped to values between 1/10 and 1/5 their initial concentrations in batch tests using mixtures of AMD and OMWW, and to 1/2 their initial concentrations in flow-through tests. The final total phenol concentrations were still above the ELV for wastewater discharges, but phenols are not regulated in irrigation waters, and OMWW is used by some producers to irrigate soils. Six main SRB groups were identified as likely having a fundamental role in the bioremediation process: the genera Desulfovibrio, Sulfurospirillum, and Acetobacter and the families Sphingomonadaceae, Prevotellaceae, and Deferribacteraceae.

Epigallocatechin Gallate Protects Mice against Methionine-Choline-Deficient-Diet-Induced Nonalcoholic Steatohepatitis by Improving Gut Microbiota To Attenuate Hepatic Injury and Regulate Metabolism.

Epigallocatechin gallate (EGCG) has been regarded as a protective bioactive polyphenol in green tea against nonalcoholic steatohepatitis (NASH), but the mechanism remains poorly deciphered. Herein, we assessed the role and mechanism of EGCG on gut microbiota and the metabolism in NASH development. Forty-eight male C57BL/6J mice were fed with either a methionine–choline-sufficient diet or a methionine–choline-deficient (MCD) diet with or without EGCG administration for 4 weeks. Liver injury, inflammation, lipid accumulation, and iron overload were examined. 16S ribosomal RNA sequencing was used to detect the fecal microbiome. In our research, we observed that EGCG notably improved MCD-diet-derived gut microbiota dysbiosis, as proved by a distinctively clustered separation from that of the MCD group and by the decrease of the Oxalobacter, Oscillibacter, Coprococcus_1, and Desulfovibrio genera and enrichment of norank_f__Bacteroidales_S24_7_group, Alloprevotella, and Bacteroides. Spearman-correlation heatmap analysis indicated that Bacteroides and Alloprevotella induced by EGCG were strongly negatively correlated with lipid accumulation. Functional enzymes of the gut microbiome were predicted by PICRUSt based on the operation classification unit. The results revealed that 1468 enzymes were involved in various metabolic pathways, and 371 enzymes showed distinct changes between untreated and EGCG-treated mice. Long-chain-fatty-acid-CoA ligase ACSBG played a distinct role in fatty acid metabolism and ferroptosis and was significantly negatively correlated with Bacteroides. Altogether, the salutary effect of EGCG on NASH might be via shifting gut flora and certain enzymes from genera. Our study thus takes a step toward NASH prevention and therapy.

Effects of the inoculum source, electron donor, and immobilization on the microbial community of sulfidogenic bioreactors

This study evaluated the biological treatment efficiency and microbial communities of eight anaerobic sequencing batch reactors treating sulfate-rich wastewater using inocula of sewage and industrial origin, immobilized or not, operated in two phases, first using lactate, and then ethanol as an electron donor. Regardless of the inoculum origin and immobilization, the maximum percentage of sulfate removal in the lactate phase was 80 ± 2%; the ethanol phase was 84 ± 3%. A lag phase in the sulfate removal was observed at the beginning of the reactor operation (lactate phase) for both types of sludge-inoculated reactors. The maximum chemical oxygen demand removal in the lactate phase was 70 ± 4%; the ethanol phase was 65 ± 5%. Pyrosequencing analysis demonstrated an increased abundance of sulfate-reducing bacteria. Only the reactors inoculated with industrial sludge presented methanogenic Archaea abundance of 3.44 and 4.15% in the lactate and ethanol phases, respectively. The genus Desulfovibrio was found in an abundance of 25.21 and 34.06% with ethanol as a carbon source in the reactors with the immobilized inocula of industrial origin, demonstrating the ability of the microbial consortium to adapt to the substrate and microenvironment. Understanding the potential for the effects of electron donors, inoculum origin, and its immobilization in the sulfate reduction and development of the microbial community can facilitate the establishment of strategies for the bioremediation of acid mine drainage.

Microbial Diversity and Potential Sulfide Producers in the Karazhanbas Oilfield (Kazakhstan)

Biogenic sulfide production in oilfields results in lower quality of oil and gas and in corrosion of oil-producing equipment. Bactericidal agents are not used at the Karazhanbas oilfield (Kazakhstan), since sulfate concentrations in both injected and formation water are low or zero. However, increasing corrosion of steel equipment and sulfide release into formation water were observed in the course of the oilfield development. The goal of the present work was to reveal the potential agents of microbial corrosion and to investigate the possibility to suppress development of sulfidogens using nitrate. Environmental conditions and the composition of microbial communities in production and injection water were studied for the sites with different temperatures. High-throughput sequencing of the V3–V4 region of the 16S rRNA gene revealed predominance of thermophilic sulfate-reducing bacteria (genera Thermodesulfobacterium, Thermodesulfovibrio, Desulfotomaculum, Thermodesulforhabdus, Desulfovirgula, Defluviitoga, and Desulfonauticus) and archaea (genus Archaeoglobus) at the high-temperature horizon, as well as of thiosulfate-reducing (genera Thermoanaerobacter, Anaerobaculum, and Coprothermobacter) and syntrophic bacteria, while abundance of methanogens (genera Methanolinea and Methanothermobacter) was low. Communities from low-temperature horizons contained mesophilic methanogens (genera Methanococcus, Methanobacterium, and Methanothrix), thermophilic and mesophilic sulfate-reducing bacteria (genera Desulfovibrio, Desulfomicrobium, Desulfosarcina, Desulfoglaeba, Desulfotignum, and Desulfocurvus), syntrophic bacteria (genus Smithella), and members of the genera Marinobacter, Paracoccus, Alcaligenes, Arcobacter, and Halomonas. Enrichment cultures of bacteria producing sulfide were obtained from formation water, as well as the cultures reducing nitrate to nitrite and suppressing growth of sulfate- and thiosulfate-reducing bacteria. These findings may indicate the possibility of using nitrate as a competitive inhibitor of sulfidogenesis in this oilfield. Corrosion-active hydrogen-utilizing methanogens and acetogens were also found, which implies the necessity for monitoring the oilfield microbial communities.

Microbial community dynamics in a crust formed on carbon steel SS400 during corrosion

ABSTRACT To obtain information on the mechanism of microbiologically influenced corrosion (MIC) under anaerobic conditions, metabolic processes and microbial community dynamics were analysed for MIC of carbon steel with lake-mud microbial consortium as inoculum. During one month of MIC experiment, the microbial consortium corroded carbon steel with sulphate reduction, methane and acetate production. The bacterial and archaeal community structure in the suspension culture and the crust formed on carbon steel were compared using high-throughput Illumina MiSeq sequencing and quantitative polymerase chain reaction. The data indicated that sulphate-reducing bacterium (Desulfovibrio genus), amino acid-degrading bacterium (Aminobacterium genus) and a hydrogenotrophic methanogen Methanofollis among Archaea increased in the crust. These microbes were estimated to collaboratively induced corrosion of carbon steel under anaerobic condition.

Biostimulation of sulfate-reducing bacteria and metallic ions removal from coal mine-impacted water (MIW) using shrimp shell as treatment agent

This paper comprises several assays aiming to identify the basis for the bioremediation of mine-impacted water (MIW). To do so, the conditions for build anoxic microcosms for treating this effluent were varied, containing MIW, and a source of chitin, to biostimulate sulfate-reducing bacteria (SRB). The chitin sources were: commercial chitin (CHIT) and shrimp shell (SS), which in addition to chitin, contains CaCO3, and proteins in its composition. The CHIT assays were not successful in sulfate-reduction, even when the pH was increased with CaCO3. However, in all SS assays the SRB development was successful (85% sulfate removal for assay 3), including the metal-free (MF-SS) assay (75% for assay 5). High-throughput sequencing analysis revealed the structure of bacterial community in the SS assay: the most abundant genera were Clostridium and Klebsiella, both fermentative and chitinase producers; a few SRB from the genera Desulfovibrio and Desulfosporosinus were also detected. In the MF-SS assay, Desulfovibrio genuswas detected but Comamonas was dominant. It could be deduced that SS is a suitable substrate for SRB development, but CHIT is not. The sulfate-reduction process was provided by the cooperation between fermentative/chitinase-producer bacteria together with SRB, which leads to efficient MIW treatment, removing sulfate and metallic ions.

Efficient treatment of alizarin yellow R contained wastewater in an electrostimulated anaerobic-oxic integrated system

An electrostimulated anaerobic-oxic integrated system was constructed for treating alizarin yellow R (AYR) containing wastewater. In electro-stimulated anaerobic unit, AYR decolorization efficiency improved from 51.2% to 96.6%. Two amination metabolites, p-phenylenediamine and 5-aminosalicylic acid, went through oxidation, ammonification and mineralization in oxic unit. Electro-stimulation promoted denitrification and COD removal efficiencies by 15.5% and 8.6%, respectively. A 20% improved nitrification efficiency was observed in oxic unit, due to elimination of AYR toxicity inhibition. No corrosion of heat-treated stainless steel occurred during the 60 days of continuous operation. Electrons sunk in denitrification and decolorization accounted for 34.4–36.8% of those released from COD removal, and 7.3% increase of removed nitrogen in nitrogenous compounds (AYR, nitrate and ammonia) was found. Electro-stimulated anaerobic unit predominated with fermentation and denitrification genera (Propionispira, Rhodocyclus, etc.) and aboundance of electro-active decolorization genus (Desulfovibrio, etc.) increased. Ammonia-oxidizing genus, Comamonas, was the most abundant in aerobic unit. Compared to the suspension, the electrostimulation could increased the abundance of electro-active genera in cathodic biofilm. This study revealed the feasibility of applying electro-stimulation and the conversion laws of nitrogenous organics in secondary bio-treatment system for treating toxic nitrogenous organics-contained wastewater.

Recent Advances in Metabolic Pathways of Sulfate Reduction in Intestinal Bacteria.

Sulfate is present in foods, beverages, and drinking water. Its reduction and concentration in the gut depend on the intestinal microbiome activity, especially sulfate-reducing bacteria (SRB), which can be involved in inflammatory bowel disease (IBD). Assimilatory sulfate reduction (ASR) is present in all living organisms. In this process, sulfate is reduced to hydrogen sulfide and then included in cysteine and methionine biosynthesis. In contrast to assimilatory sulfate reduction, the dissimilatory process is typical for SRB. A terminal product of this metabolism pathway is hydrogen sulfide, which can be involved in gut inflammation and also causes problems in industries (due to corrosion effects). The aim of the review was to compare assimilatory and dissimilatory sulfate reduction (DSR). These processes occur in some species of intestinal bacteria (e.g., Escherichia and Desulfovibrio genera). The main attention was focused on the description of genes and their location in selected strains. Their coding expression of the enzymes is associated with anabolic processes in various intestinal bacteria. These analyzed recent advances can be important factors for proposing possibilities of metabolic pathway extension from hydrogen sulfide to cysteine in intestinal SRB. The switch from the DSR metabolic pathway to the ASR metabolic pathway is important since toxic sulfide is not produced as a final product.

Sulfate Reduction for Bioremediation of AMD Facilitated by an Indigenous Acidand Metal-Tolerant Sulfate-Reducer.

Acid mine drainage (AMD) has been a serious environmental issue that threatens soil and aquatic ecosystems. In this study, an acid-tolerant sulfate-reducing bacterium, strain S4, was isolated from the mud of an AMD storage pond in Vietnam via enrichment in anoxic mineral medium at pH 5. Comparative analyses of sequences of the 16S rRNA gene and dsrB gene involved in sulfate reduction revealed that the isolate belonged to the genus Desulfovibrio, and is most closely related to Desulfovibrio oxamicus (with 99% homology in 16S rDNA sequence and 98% homology in dsrB gene sequence). Denaturing gradient gel electrophoresis (DGGE) analyses of dsrB gene showed that strain S4 represented one of the two most abundant groups developed in the enrichment culture. Notably, strain S4 was capable of reducing sulfate in low pH environments (from 2 and above), and resistance to extremely high concentration of heavy metals (Fe 3,000 mg/l, Zn 100 mg/l, Cu 100 mg/ l). In a batch incubation experiment in synthetic AMD with pH 3.5, strain S4 showed strong effects in facilitating growth of a neutrophilic, metal sensitive Desulfovibrio sp. strain SR4H, which was not capable of growing alone in such an environment. Thus, it is postulated that under extreme conditions such as an AMD environment, acid- and metal-tolerant sulfate-reducing bacteria (SRB)- like strain S4 would facilitate the growth of other widely distributed SRB by starting to reduce sulfate at low pH, thus increasing pH and lowering the metal concentration in the environment. Owing to such unique physiological characteristics, strain S4 shows great potential for application in sustainable remediation of AMD.

Enhancement of hydrogen production and energy recovery through electro-fermentation from the dark fermentation effluent of food waste

To enhance hydrogen production efficiency and energy recovery, a sequential dark fermentation and microbial electrochemical cell (MEC) process was evaluated for hydrogen production from food waste. The hydrogen production, electrochemical performance and microbial community dynamics were investigated during startup of the MEC that was inoculated with different sludges. Results suggest that biogas production rates and hydrogen proportions were 0.83 ​L/L d and 92.58%, respectively, using anaerobic digested sludge, which is higher than that of the anaerobic granular sludge (0.55 ​L/L d and 86.21%). The microbial community were predominated by bacterial genus Acetobacterium, Geobacter, Desulfovibrio, and archaeal genus Methanobrevibacter in electrode biofilms and the community structure was relatively stable both in anode and cathode. The sequential system obtained a 53.8% energy recovery rate and enhanced soluble chemical oxygen demand (sCOD) removal rate of 44.3%. This research demonstrated an important approach to utilize dark fermentation effluent to maximize the conversion of fermentation byproducts into hydrogen.

Genome insights of mercury methylation among Desulfovibrio and Pseudodesulfovibrio strains

Mercury methylation converts inorganic mercury into the toxic methylmercury, and the consequences of this transformation are worrisome for human health and the environment. This process is performed by anaerobic microorganisms, such as several strains related to Pseudodesulfovibrio and Desulfovibrio genera. In order to provide new insights into the molecular mechanisms of mercury methylation, we performed a comparative genomic analysis on mercury methylators and non-methylators from (Pseudo)Desulfovibrio strains. Our results showed that (Pseudo)Desulfovibrio species are phylogenetically and metabolically distant and consequently, these genera should be divided into various genera. Strains able to perform methylation are affiliated with one branch of the phylogenetic tree, but, except for hgcA and hgcB genes, no other specific genetic markers were found among methylating strains. hgcA and hgcB genes can be found adjacent or separated, but proximity between those genes does not promote higher mercury methylation. In addition, close examination of the non-methylator Pseudodesulfovibrio piezophilus C1TLV30 strain, showed a syntenic structure that suggests a recombination event and may have led to hgcB depletion. The genomic analyses identify also arsR gene coding for a putative regulator upstream hgcA. Both genes are cotranscribed suggesting a role of ArsR in hgcA expression and probably a role in mercury methylation.

Traditional Processed Meat Products Re-designed Towards Inulin-rich Functional Foods Reduce Polyps in Two Colorectal Cancer Animal Models

Inulin-rich foods exert a prebiotic effect, as this polysaccharide is able to enhance beneficial colon microbiota populations, giving rise to the in situ production of short-chain fatty acids (SCFAs) such as propionic and butyric acids. These SCFAs are potent preventive agents against colorectal cancer due to their histone deacetylases inhibitory properties, which induce apoptosis in tumor colonocytes. As colorectal cancer is the fourth most common neoplasia in Europe with 28.2 new cases per 100,000 inhabitants, a cost-effective preventive strategy has been tested in this work by redesigning common porcine meat products (chorizo sausages and cooked ham) consumed by a substantial proportion of the population towards potential colorectal cancer preventive functional foods. In order to test the preventive effect of these inulin-rich meat products against colorectal cancer, an animal model (Rattus norvegicus F344) was used, involving two doses of azoxymethane (10 mg/kg) and two treatments with dextran sodium sulfate (DSS) during a 20-week assay period. Control feed, control sausages, functional sausages (15.7% inulin), control cooked ham and functional cooked ham (10% inulin) were used to feed the corresponding animal cohorts. Then, the animals were sacrificed and their digestive tract tissues were analyzed. The results showed a statistically significant 49% reduction in the number of colon polyps in the functional meat products cohorts with respect to the control meat products animals, as well as an increase in the cecum weight (an indicator of a diet rich in prebiotic fiber), a 51.8% increase in colon propionate production, a 39.1% increase in colon butyrate concentrations, and a reduction in the number of hyperplastic Peyer’s patches. Metagenomics studies also demonstrated colon microbiota differences, revealing a significant increase in Bacteroidetes populations in the functional meat products (mainly due to an increase in Bacteroidaceae and Prevotellaceae families, which include prominent propionate producers), together with a reduction in Firmicutes (especially due to lower Lachnospiraceae populations). However, functional meat products showed a remarkable increase in the anti-inflammatory and fiber-fermentative Blautia genus, which belongs to this Lachnospiraceae family. The functional meat products cohorts also presented a reduction in important pro-inflammatory bacterial populations, such as those of the genus Desulfovibrio and Bilophila. These results were corroborated in a genetic animal model of CRC (F344/NSlc-Apc1588/kyo) that produced similar results. Therefore, processed meat products can be redesigned towards functional prebiotic foods of interest as a cost-effective dietary strategy for preventing colorectal cancer in human populations.

The Sulfate-Reducing Microbial Communities and Meta-Analysis of Their Occurrence during Diseases of Small-Large Intestine Axis.

Sulfate-reducing bacteria (SRB) are often isolated from animals and people with ulcerative colitis and can be involved in the IBD development in the gut–intestine axis. The background of the research consisted of obtaining mixed cultures of SRB communities from healthy mice and mice with colitis, finding variation in the distribution of their morphology, to determine pH and temperature range tolerance and their possible production of hydrogen sulfide in the small–large intestinal environment. The methods: Microscopic techniques, biochemical, microbiological, and biophysical methods, and statistical processing of the results were used. The results: Variation in the distribution of sulfate-reducing microbial communities were detected. Mixed cultures from mice with ulcerative colitis had 1.39 times higher production of H2S in comparison with samples from healthy mice. The species of Desulfovibrio genus play an important role in diseases of the small–large intestine axis. Meta-analysis was also used for the observation about an SRB occurrence in healthy and not healthy individuals and the same as their metabolic processes. Conclusions: This finding is important for its possible correlation with inflammation of the intestine, where the present of SRB in high concentration plays a major part. It can be a good possible indicator of the occurrence of IBD.

Bacterial community structure and predicted function in an acidogenic sulfate-reducing reactor: Effect of organic carbon to sulfate ratios

A lab-scale acidogenic sulfate-reducing reactor with N2 stripping was continuously operated to uncover its microbial mechanism treating highly sulfate-containing organic wastewaters. Results showed that sulfate reduction efficiency decreased with the influent COD/sulfate ratios. Microbial community analysis showed that VFA accumulation mainly caused by the predominance of fermentative bacteria including Streptococcus and Oceanotoga. Genus Desulfovibrio was the most predominant SRB and enriched at low influent COD/sulfate ratios. Although Bifidobacterium, Atopobium, Wohlfahrtiimonas, Dysgonomonas etc. had low average abundance, they were identified keystone genera by the co-occurrence network analysis. The functions of the microbial community were not insignificantly influenced by COD/sulfate ratios. All predicted functional genes involved in dissimilatory sulfate reduction reached their maximum abundances at influent COD/sulfate ratio of 1.5, while the assimilatory sulfate reduction was favored at the COD/sulfate ratio lower than 2.

Comparative metagenomic sequencing analysis of cecum microbiotal diversity and function in broilers and layers.

The composition of the gastrointestinal microorganisms in poultry is closely associated with the host and its environment. In this study, using 16S rRNA and metagenomic techniques, we comprehensively analyzed the structure and diversity of the cecal microbiota of broiler chickens (BC) and laying hens (LH). The 16S rRNA sequencing analysis showed Firmicutes, Bacteroidetes, and Proteobacteria were the main cecal bacterial phyla in BC and LH. However, at the genus level, LH had a greater abundance of Bacteroides (P < 0.05), Rikenellaceae_RC9_gut_group (P < 0.01), Phascolarctobacterium (P < 0.05), Desulfovibrio (P < 0.05), Prevotellaceae_UCG-001 (P < 0.05), and unclassified_o_Bacteroidales (P < 0.05), whereas BC had a greater abundance of Alistipes (P < 0.05), Rikenella (P < 0.05), Ruminococcaceae_UCG-005 (P < 0.05), Lachnoclostridium (P < 0.05), and unclassified_f_Ruminococcaceae (P < 0.05). It is particularly noteworthy that the genus Desulfovibrio was significantly more abundant in the LH cecum than in the BC cecum (P < 0.05). A metagenomic analysis showed that the annotations in the LH dataset were significantly more abundant than in the BC dataset, and included replication, recombination and repair, energy production and transformation, cell wall/membrane/envelope biogenesis, and amino acid transport and metabolism-related functions (P < 0.05). This study indicates that microbial genotypic differences in chickens of the same species can cause changes in the abundances of the gut microbiota, but do not alter the structural composition or major functional characteristics of the gut microbiota.