Genomic architecture of three newly isolated unclassified Butyrivibrio species elucidate their potential role in the rumen ecosystem

One cellulose-degrading strain CB08 and two xylan-degrading strains XB500-5 and X503 were isolated from buffalo rumen. All the strains were designated as putative novel species of Butyrivibrio based on phylogeny, phylogenomy, digital DNA-DNA hybridization, and average nucleotide identity with their closest type strains. The draft genome length of CB08 was ~3.54 Mb, while X503 and XB500-5 genome sizes were ~3.24 Mb and ~3.27 Mb, respectively. Only 68.28% of total orthologous clusters were shared among three genomes, and 40-44% of genes were identified as hypothetical proteins. The presence of genes encoding diverse carbohydrate-active enzymes (CAZymes) exhibited the lignocellulolytic potential of these strains. Further, the genome annotations revealed the metabolic pathways for monosaccharide fermentation to acetate, butyrate, lactate, ethanol, and hydrogen. The presence of genes for chemotaxis, antibiotic resistance, antimicrobial activity, synthesis of vitamins, and essential fatty acid suggested the versatile metabolic nature of these Butyrivibrio strains in the rumen environment.

Comparative genome analysis of Clostridium beijerinckii strains isolated from pit mud of Chinese strong flavor baijiu ecosystem

Clostridium beijerinckii is a well-known anaerobic solventogenic bacterium which inhabits a wide range of different niches. Previously, we isolated five butyrate-producing C. beijerinckii strains from pit mud (PM) of strong-flavor baijiu (SFB) ecosystems. Genome annotation of the five strains showed that they could assimilate various carbon sources as well as ammonium to produce acetate, butyrate, lactate, hydrogen, and esters but did not produce the undesirable flavours isopropanol and acetone, making them useful for further exploration in SFB production. Our analysis of the genomes of an additional 233 C. beijerinckii strains revealed an open pangenome based on current sampling and will likely change with additional genomes. The core genome, accessory genome, and strain-specific genes comprised 1567, 8851, and 2154 genes, respectively. A total of 298 genes were found only in the five C. beijerinckii strains from PM, among which only 77 genes were assigned to Clusters of Orthologous Genes (COG) categories. In addition, 15 transposase and 12 phage integrase families were found in all five C. beijerinckii strains from PM. Between 18 and 21 genome islands (GIs) were predicted for the five C. beijerinckii genomes. The existence of a large number of MGEs indicated that the genomes of the five C. beijerinckii strains evolved with the loss or insertion of DNA fragments in the PM of SFB ecosystems. This study presents a genomic framework of C. beijerinckii strains from PM that could be used for genetic diversification studies and further exploration of these strains.

Effects of ad libitum free-choice access to freshly squeezed domestic white asparagus juice on intestinal microbiota composition and universal biomarkers of immuno-metabolic homeostasis and general health in middle-aged female and male C57BL/6 mice

Background and purpose: Asparagus contains different bioactive and volatile components including pyrazines, sulphur-containing compounds, and polyphenols. Asparagus juice is a new low-calorie LAB-containing natural juice product, the usage of which is expanding. Pyrazines and sulphur-containing compounds are degraded by bacteria on one hand, but on the other hand, dietary polyphenols prevent human colorectal diseases as modulators of the composition and/or activity of gut microbiota. However, the utility of these asparagus compounds for reversal of age-associated microbial dysbiosis and the immunometabolic disorders that dysbiosis incites body inflammatory reactions was not much explored so far. Hence, using middle-aged mice, we conducted the current study to verify the effect of freshly squeezed domestic white asparagus juice on the biomarkers reflecting immuno-metabolic pathways linking age-related dysbiosis and metabolic events. Materials and Methods: Thirty-two conventional Harlan Laboratories C57BL/6 mice aged between 11-12 months were randomly divided into two groups (n=16). Mice in control group 1 received sterile tap water. Animals in group 2 had 60 days ad libitum free-choice access to sterile tap water supplemented with 5% (v/v) freshly squeezed domestic white asparagus juice. Clinical signs of general health, hydration, and inflammation were monitored daily. Caecal content samples were analysed by qPCR for microbial composition. Histology of relevant organs was carried out on day 60 after sacrificing the mice. Universal markers of metabolic- and liver function were determined in serum samples. Caecal SCFAs contents were measured using HPLC. Results: Overall, no significant differences in general health or clinical signs of inflammation between the two groups were observed. The liver to body weight ratio in asparagus juice-drank mice was lowered. The qPCR quantification showed that asparagus juice significantly decreased the caecal Clostridium coccoides group while causing an enhancement in Clostridium leptum, Firmicutes, and bifidobacterial groups as well as total caecal bacterial count. Asparagus juice significantly elevated the caecal contents of SCFAs. Enhanced SCFAs (acetate, butyrate, and propionate) in mice receiving asparagus juice, however, did coincide with altered lipid levels in plasma or changes in the abundance of relevant bacteria for acetate-, butyrate-, and propionate production. Discussion: To the best of our knowledge, this is the first study aiming at evaluating the effect of freshly squeezed German domestic white asparagus juice on universal markers of metabolic- and liver function in middle-aged mice and the role of gut microbiota in this regard. The effectiveness of asparagus juice to improve metabolism in middle-aged mice was associated with alterations in intestinal microbiota but maybe also due to uptake of higher amounts of SCFAs. Hence, the key signal pathways corresponding to improved immune-metabolic homeostasis will be an important research scheme in the future.

Effects of Differences in Fibre Composition and Maturity of Forage-Based Diets on the Microbial Ecosystem and Its Activity in Equine Caecum and Colon Digesta and Faeces

Fibrous feeds are essential for horses. When developing feeding regimens promoting health and performance, we need to understand the digestion of plant cell walls and the functioning of the hindgut microbial ecosystem. Our objective was to investigate the effect of grass fibre maturity and legume forage on the hindgut microbiota and its activity. Six caecum and colon fistulated geldings were fed three diets differing in fibre composition: concentrate and late harvested grass haylage (35:65 energy ratio) (C); early and late harvested grass haylage (80:20) (G); lucerne and late harvested grass haylage (80:20) (L) for 28 days in a Latin-square design. No differences were measured in total bacteria concentrations, fungi and protozoa numbers nor in cellulolytic bacteria concentrations between the diets. Short-chain fatty acid concentrations did not differ between diets, but a lower (acetate + butyrate)/propionate ratio when the horses were fed Diet C, compared to G and L, was observed, suggesting lower fibrolytic and higher amylolytic activity. The pH increased when the horses were fed Diet L and decreased when fed C and G from caecum to faeces. The buffering capacity (BC) of hindgut digesta was five to fifteen-fold higher than that of the feeds, suggesting a decreased effect of feed BC as digesta travelled through the digestive tract. In conclusion, an early harvested forage opens up the possibility for forage-only diets, providing high energy without the negative effects of concentrate.

In vitro impact of condensed tannins on the caecal metabolites of chickens

Tannins are a diverse group of plant phenolic compounds. Condensed tannins (CTs) represent a major subgroup of tannins and were extracted from tilia (Tilia L.) flowers and black locust (Robinia pseudoacacia) leaves. These extracts were examined for their effects on the metabolic profile of chicken caeca. By using in vitro, a nuclear magnetic resonance (1H-NMR), which was combined with multivariate statistics, the current study was applied for the first time to investigate how three different CT compositions, procyanidins (PC) and/or prodelphinidins (PD) units influenced the metabolic end-products in caecal contents of chickens. In the presence of tannins, glutamate, leucine, lysine, pyroglutamate, phenylalanine, proline, and sarcosine were significantly decreased. CT extracts significantly influenced the fermentation, increasing the concentrations of some fatty acids such as acetate, butyrate, and propionate whereas. In contrast, lactate decreased between the treatments. This study identified the key structural features of CTs that contain either high molar proportions of PD or PC, which might be useful to improve the efficiency of feed utilization in chickens.

Formation of effective concentration of film forming superhydrophobic coatings based on silicon dioxide

The object of research is the hydrophobization of a coating based on styrene-acrylic copolymer and cellulose acetate butyrate with pyrogenic silicon dioxide. The hydrophobicity or hydrophilicity of a surface depends mainly on the chemical structure of the surface and its roughness. A relief hydrophilic surface will be wetted much more easily than a flat surface of the same material, and vice versa – an increase in the roughness of a hydrophobe is accompanied by a more pronounced repulsion of water. The size and number of irregularities significantly affect the wetting characteristics of the investigated surface. The combination of low surface energy and relief structure forms a superhydrophobic surface. Such surfaces have found application in self-cleaning, frost-resistant, antifriction, electrically conductive and oil-sorbing coatings. In this work, styrene-acrylic copolymer and cellulose acetate butyrate were used as a film former. Pyrogenic silicon dioxide Aerosil R 972, which was hydrophobized with dimethyldichlorosilane, was used as a nanofiller. In this work, the compositions were applied to laboratory glasses by dip coating. The determination of surface energy was carried out using glycerin and diiodomethane. The hydrophobic properties of the coatings were evaluated by measuring the contact angles with water using a goniometer. The analysis of the morphological structure of the coating surface with photographs of a scanning electron microscope has been carried out. The energy state of the surface of the created superhydrophobic coatings has been determined and their surface energies have been calculated using the technique based on the Owens-Wendt model. The process of hydrophobization of polymer-based coatings is investigated, which occurs both due to chemical modification with the introduction of silicon dioxide and due to the creation of nanoroughness of the surface layer of the coatings. The dependences of this process on materials are investigated using an electron microscope and the determination of their surface energy depending on the SiO2 filling. The values of the critical concentration of the modifier for the transition of polymers to the superhydrophobic state have been determined. As a result, the influence of polymer crystallinity on hydrophobization was determined by comparing changes in the surface energy of materials during their modification.