Metabolic syndrome is a complex disease that is exponentially increasing in the western world, and diet is one of the possible ways to improve the metabolic status of patients. Barley beta glucans ...are dietary fibres that show promise for improvement cholesterol levels and postprandial glucose response, but they have been rarely investigated in human trials with concurrent focus on gut microbiota.
A double-blind, placebo-controlled, randomised clinical trial was conducted with 43 volunteers with high risk for metabolic syndrome development or with diagnosed metabolic syndrome. During a four-week intervention study, participants consumed experimental bread containing 6 g of barley beta glucans or equal bread but without beta glucans. After dietary intervention, total plasma cholesterol decreased in the test group (−0.26 ± 0.54, p = 0.019), but not in the control group. Short chain fatty acids (SCFA) composition in faeces significantly changed with increase of propionic acid in test group (43.2%, p = 0.045) and with decrease of acetic acid in control group (41.8%, p = 0.011). The microbiome analysis based on Illumina paired end sequencing of 16S rRNA genes showed a decrease in microbial diversity and richness in the test group. The pre-intervention gut microbiota composition showed higher abundance of health associated Bifidobacterium spp. and Akkermansia municiphila within cholesterol-responsive group, showing that diet-induced metabolic response is possibly dependent on individual gut microbiota composition.
Display omitted
•After beta glucans dietary intervention total plasma cholesterol levels decreased.•Short chain fatty acids significantly changed with increase of propionic acid.•After dietary intervention significant changes in microbiota composition occurred.•Pre-intervention gut microbiota appears to be a factor influencing the metabolic response.
One century is passing by from the foundation of one of the most respected research institutes in the field of animal and human nutrition, the Scottish Institute The Rowett Research Institute (RRI). ...In addition to the exceptional influence on the development of the science of nutrition itself, RRI researchers have been significantly involved in the development of science of nutrition and, particularly, of microbiology related to animal and human nutrition in Slovenia. Since the early 1980s, several Slovenian microbiologists have visited RRI, conducted research and developed personal contacts, some retained for more than 40 years. The cooperation was extremely fruitful, which is reflected through joint scientific publications and their visibility, the implementation of formal and informal research projects, and the collaboration in organization of international scientific symposiums. Slovenian researchers, who visited the RRI, built their own careers on the basis of the acquired knowledge and significantly contributed to the development of microbiology in Slovenia. They importantly participated in the establishment of a university study of Microbiology, which will shortly celebrate its 25th anniversary, and is due to its achievements the pride of Biotechnical Faculty and of University of Ljubljana.
Despite a considerable interest in prodigiosin, the mechanism of its antibacterial activity is still poorly understood. In this work, Escherichia coli cells were treated with prodigiosin to determine ...its antimicrobial effect on bacterial physiology. The effect of prodigiosin was concentration dependent. In prodigiosin treated cells above MIC value no significant DNA damage or cytoplasmic membrane disintegration was observed. The outer membrane, however, becomes leaky. Cells had severely decreased respiration activity. In prodigiosin treated cells protein and RNA synthesis were inhibited, cells were elongated but could not divide. Pre-treatment with prodigiosin improved E. coli survival rate in media containing ampicillin, kanamycin and erythromycin but not phleomycin. The results suggest that prodigiosin acts as a bacteriostatic agent in E. coli cells. If prodigiosin was diluted, cells resumed growth. The results indicate that prodigiosin has distinct mode of antibacterial action in different bacteria.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Prodigiosin produced by marine bacterium Vibrio ruber DSM 14379 exhibits a potent antimicrobial activity against a broad range of Gram positive and Gram negative bacteria. The mechanism of ...prodigiosin antimicrobial action, however, is not known. In this work, the effect of prodigiosin on Bacillus subtilis growth, cell membrane leakage, and induction of autolysins was studied. Treating B. subtilis with prodigiosin resulted in rapid decline of optical density and increased cell membrane leakage measured by β-galactosidase activity. Cell lysis was initiated immediately after treatment with prodigiosin in the middle exponential phase and was completed within 2 h. Lytic activity of prodigiosin in mutant strains with impaired autolysin genes lytABCD decreased for 80% compared to the wild type strain, while in lytABCDEF mutant strain prodigiosin had no bacteriolytic but only bacteriostatic effect. Fast prodigiosin lytic activity on individual B. subtilis cells was confirmed by a modified comet assay. The results indicate that prodigiosin autolysin induction in B. subtilis is growth phase dependent.
27 strains representing eight new Prevotella species were isolated from rumen of a single sheep in eight weeks interval. One of the putative species encompassing the highest number of isolated ...strains which also exhibited some genetic variability in preliminary data, was then selected for description of a novel species. We examined six strains in genomic and phenotypic detail, two of which may actually be the same strain isolated nearly three weeks apart. Other strains formed clearly diverged intraspecies lineages as evidenced by core genome phylogeny and phenotypic differences. Strains of the proposed new Prevotella species are strictly saccharolytic as is usual for rumen Prevotella, and use plant cell-wall xylans and pectins for growth. However, the range of cell-wall polysaccharides utilised for growth is rather limited compared to rumen generalists such as Prevotella bryantii or Prevotella ruminicola and this extends also to the inability to utilise starch, which is unexpected for the members of the genus Prevotella. Based on the data obtained, we propose Prevotella communis sp. nov. to accommodate strain E1-9T as well as other strains with the similar properties. The proposed species is widespread: two other strains were previously isolated from sheep in Japan and is also common in metagenomic data of cattle and sheep rumen samples from Scotland and New Zealand. It was also found in a collection of metagenome-assembled genomes originating from cattle in Scotland. Thus, it is a ubiquitous bacterium of domesticated ruminants specialising in degradation of a somewhat restricted set of plant cell wall components.
The huge amounts of keratin-rich waste generated daily by various industries, slaughterhouses, and processing plants need to be properly managed. Most keratin degradation-related research focuses on ...keratin from bird feathers, but a vast minority focuses on keratin from sheep wool, which also presents a serious environmental problem. In this article, we describe the isolation, identification, and characterization of new keratinolytic microorganisms capable of sheep wool degradation from sheep wool and soil enriched with wool keratin. We isolated four bacterial species from the genus
Bacillus
(
B. subtilis, B. altitudinis, B. mycoides
, and
B. wiedmannii
), one streptomycete species
Streptomyces coelicoflavus
identified by whole genome sequencing, and a fungal species
Aphanoascus reticulisporus
. In some of the isolated microorganisms, we detected keratinolytic activity for the first time, and for most of them, the ability to degrade sheep wool has not been previously demonstrated. The keratinases of the new isolates are active in a wide range of temperatures (25–85 °C) and pH (6.0–10.0), so all isolates show great potential for further biotechnological use in industry and in various environmental and agricultural applications to reduce and recycle keratin-rich wastes such as sheep wool and waste woollen textiles.
Anaerobic digestion, despite its preferable use as a treatment for high organic matter polluted waste streams, is susceptible to inhibitors, salt included. Therefore, two different experiments were ...conducted to observe the responses of bacterial and archaeal communities to hypersaline environments. In the first experiment, salt was added gradually, while in the second experiment, salt was added rapidly (so-called salt shocks were performed). The results of the gradual addition of salt showed a recovery of methane production after the salt concentration decreased. The NaCl concentration of 28.2 g/L seems to be the limit between stable operation and occurrence inhibition. The specific biogas production varied between 0.490 and 0.562 m3/kgtCOD during the stepwise salt addition, depending on the salt concentration, while the maximal achieved COD removal was 79.8%. The results of the rapid salt addition showed good recovery of the bacterial community, while a reduction of salt-sensitive species was observed in the archaeal community. The trend of specific biogas production during rapid salt addition was stable with an average value of 0.590 m3/kgtCOD, and it was observed that higher concentrations of up to 39.4 g/L of NaCl were tolerated. The maximum COD removal achieved during rapid salt addition was 83.1%. In conclusion, certain bacterial and archaeal communities were well-adapted to the hypersaline environment and remained active during the anaerobic digestion of substrates with high salt concentration.
To date, there is sparse information for the genus
with
CC-AMO-30D
as the only described member. We report here a new species isolated from mangrove soil collected at Malaysia Tanjung Piai National ...Park and perform polyphasic characterization to determine its taxonomic position. Strain CL23
is a Gram-negative, yellow-pigmented, strictly aerobic, catalase-positive and oxidase-positive bacterium. The optimal growth conditions were determined to be at pH 7.0, 30-37 °C and in 1-2 % (w/v) NaCl. The major respiratory quinone was menaquinone-6 (MK-6) and the highly abundant polar lipids were four unidentified lipids, a phosphatidylethanolamine and two unidentified aminolipids. The 16S rRNA gene similarity between strain CL23
and
CC-AMO-30D
is 96.67 %. Strain CL23
and
CC-AMO-30D
clustered together and were distinguished from taxa of closely related genera in 16S rRNA gene phylogenetic analysis. Genome sequencing revealed that strain CL23
has a genome size of 4.4 Mbp and a G+C content of 40.72 mol%. Overall genome related indexes including digital DNA-DNA hybridization value and average nucleotide identity are 17.70 % and approximately 70%, below the cutoffs of 70 and 95%, respectively, indicated that strain CL23
is a distinct species from
CC-AMO-30D
. Collectively, based on the phenotypic, chemotaxonomic, phylogenetic and genomic evidences presented here, strain CL23
is proposed to represent a new species with the name
sp. nov. (KCTC 72252
=LMG 31418
). An emended description of the genus
is also proposed.
Herbivorous animals harbour potent cellulolytic and hemicellulolytic microorganisms that supply the host with nutrients acquired from degradation of ingested plant material. In addition to protozoa ...and fungi, rumen bacteria contribute a considerable part in the breakdown of recalcitrant (hemi)cellulosic biomass. The present review is focused on the enzymatic systems of three representative fibrolytic rumen bacteria, namely Ruminococcus flavefaciens, Prevotella bryantii and Pseudobutyrivibrio xylanivorans. R. flavefaciens is known for one of the most elaborated cellulosome architectures and might represent a promising candidate for the construction of designer cellulosomes. On the other hand, Prevotella bryantii and Pseudobutyrivibrio xylanivorans produce multiple free, but highly efficient xylanases. In addition, P. xylanivorans was also shown to have some probiotic traits, which makes it a promising candidate not only for biogas production, but also as an animal feed supplement. Genomic and proteomic analyses of cellulolytic and hemicellulolytic bacterial species aim to identify novel enzymes, which can then be cloned and expressed in adequate hosts to construct highly active recombinant hydrolytic microorganisms applicable for different biotechnological tasks.
A total of 11 ruminal strains currently assigned to Butyrivibrio fibrisolvens and Pseudobutyrivibrio xylanivorans were cultivated in two different media, rumen fluid containing M2 and short-chain ...fatty acid (SCFA) containing M330, and their cellular fatty acid methyl esters (FAME) and dimethylacetals (DMA) were analyzed using gas chromatography. A comparison of the FAME/DMA compositions revealed that the difference in SCFA contents in the growth medium induced a pronounced quantitative effect on the cellular branched-chain fatty acid and aldehydes proportions only in the P. xylanivorans strains. This study shows that FAME/DMA analysis is a powerful chemotaxonomic tool in the group of phenotypically similar rumen butyrivibria especially when the influence of the growth medium is evaluated.
PDF
