Hydrogen sulfide effects on the survival of lactobacilli with emphasis on the development of inflammatory bowel diseases

The gut microbiota is a complex component of humans that depends on diet, host genome, and lifestyle. The background:The study purpose is to find relations between nutrition, intestinal lactic acid bacteria (LAB) from various environments (human, animal intestine, and yogurt) and sulfate-reducing microbial communities in the large intestine; to compare kinetic growth parameters of LAB; and to determine their sensitivity to different concentration of hydrogen sulfide produced by intestinal sulfate-reducing bacteria. Methods: Microbiological (isolation and identification), biochemical (electrophoresis), molecular biology methods (DNA isolation and PCR analysis), and statistical processing (average and standard error calculations) of the results were used. The results: The toxicity of hydrogen sulfide produced by sulfate-reducing bacteria, the survival of lactic acid bacteria, and minimal inhibitory concentrations (MIC) were determined. The measured hydrogen sulfide sensitivity values were the same for L. paracasei and L. reuteri (MIC > 1.1 mM). In addition, L. plantarum and L. fermentum showed also a similar sensitivity (MIC > 0.45 mM) but significantly (p 0.45 mM). L. paracasei and L. reuteri are more sensitive to hydrogen sulfide than L. fermentum and L. plantarum. L. pentosus was sensitive to the extremely low concentration of H2S (MIC > 0.15 mM). Conclusions: The Lactobacillus species were significantly sensitive to hydrogen sulfide, which is a final metabolite of intestinal sulfate-reducing bacteria. The results are definitely helpful for a better understanding of complicated interaction among intestinal microbiota and nutrition. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.Grant Agency of the Masaryk University [MUNI/A/0902/2018

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.Grant Agency of the Masaryk University [MUNI/A/0902/2018

NADH and NADPH peroxidases as antioxidant defense mechanisms in intestinal sulfate-reducing bacteria

Animal and human feces typically include intestinal sulfate-reducing bacteria (SRB). Hydrogen sulfide and acetate are the end products of their dissimilatory sulfate reduction and may create a synergistic effect. Here, we report NADH and NADPH peroxidase activities from intestinal SRB Desulfomicrobium orale and Desulfovibrio piger . We sought to compare enzymatic activities under the influence of various temperature and pH regimes, as well as to carry out kinetic analyses of enzymatic reaction rates, maximum amounts of the reaction product, reaction times, maximum rates of the enzyme reactions, and Michaelis constants in cell-free extracts of intestinal SRB, D. piger Vib-7, and D. orale Rod-9, collected from exponential and stationary growth phases. The optimal temperature (35 °C) and pH (7.0) for both enzyme’s activity were determined. The difference in trends of Michaelis constants ( K m ) during exponential and stationary phases are noticeable between D. piger Vib-7 and D. orale Rod-9; D. orale Rod-9 showed much higher K m (the exception is NADH peroxidase of D. piger Vib-7: 1.42 ± 0.11 mM) during the both monitored phases. Studies of the NADH and NADPH peroxidases—as putative antioxidant defense systems of intestinal SRB and detailed data on the kinetic properties of this enzyme, as expressed by the decomposition of hydrogen peroxide—could be important for clarifying evolutionary mechanisms of antioxidant defense systems, their etiological role in the process of dissimilatory sulfate reduction, and their possible role in the development of bowel diseases

Influence of junction angle on three-dimensional flow structure and bed morphology at confluent meander bends during different hydrological conditions

© 2014 John Wiley & Sons, Ltd. Recent field and modeling investigations have examined the fluvial dynamics of confluent meander bends where a straight tributary channel enters a meandering river at the apex of a bend with a 90° junction angle. Past work on confluences with asymmetrical and symmetrical planforms has shown that the angle of tributary entry has a strong influence on mutual deflection of confluent flows and the spatial extent of confluence hydrodynamic and morphodynamic features. This paper examines three-dimensional flow structure and bed morphology for incoming flows with high and low momentum-flux ratios at two large, natural confluent meander bends that have different tributary entry angles. At the high-angle (90°) confluent meander bend, mutual deflection of converging flows abruptly turns fluid from the lateral tributary into the downstream channel and flow in the main river is deflected away from the outer bank of the bend by a bar that extends downstream of the junction corner along the inner bank of the tributary. Two counter-rotating helical cells inherited from upstream flow curvature flank the mixing interface, which overlies a central pool. A large influx of sediment to the confluence from a meander cutoff immediately upstream has produced substantial morphologic change during large, tributary-dominant discharge events, resulting in displacement of the pool inward and substantial erosion of the point bar in the main channel. In contrast, flow deflection is less pronounced at the low-angle (36°) confluent meander bend, where the converging flows are nearly parallel to one another upon entering the confluence. A large helical cell imparted from upstream flow curvature in the main river occupies most of the downstream channel for prevailing low momentum-flux ratio conditions and a weak counter-rotating cell forms during infrequent tributary-dominant flow events. Bed morphology remains relatively stable and does not exhibit extensive scour that often occurs at confluences with concordant beds

Weighted logics for artificial intelligence : an introductory discussion

International audienceBefore presenting the contents of the special issue, we propose a structured introductory overview of a landscape of the weighted logics (in a general sense) that can be found in the Artificial Intelligence literature, highlighting their fundamental differences and their application areas

Społeczne i ekologiczne aspekty zarządzania

Praca recenzowana / peer-reviewed pape

Kandydat z kłopotami czyli kłopotliwy kandydat - serbska akcesja do Unii Europejskiej

This article analyzes Serbian accession bid to the EU. Although a candidate country as of March 2012, Serbia will have to manage some painstaking reforms before being admitted into the Union. Even if negotiations over Serbian entry start next year, and date of entry negotiations is still unknown, it seems realistic that Serbia will not join the EU by the end of this decade. In that respect, main argument of this article is that Serbian entry to the EU is dependent on the fol¬lowing issues: battling systemic corruption and (organized) crime; relations with Kosovo; and change of political culture.Artykuł stanowi analizę serbskich dążeń do członkostwa w Unii Europejskiej. Uwzględniąc status Serbii jako państwa kandydującego do Unii Europejskiej od marca 2012 r., władze serbskie są zmuszone przeprowadzić niekiedy bolesne reformy. Nadal nieznana jest data wejścia Serbii do Unii Europejskiej, choć jasne pozostaje, że państwo to nie stanie się członkiem UE przed końcem tej dekady. Uwzględniając powyższe, w artykule wskazano, że wejście Serbii do UE uzależnione jest od: skutecznej walki z korupcją i (zorganizowan¹) przestępczością; relacji z Kosowem ; oraz zmiany kultury politycznej

Kandydat z kłopotami czyli kłopotliwy kandydat - serbska akcesja do Unii Europejskiej

This article analyzes Serbian accession bid to the EU. Although a candidate country as of March 2012, Serbia will have to manage some painstaking reforms before being admitted into the Union. Even if negotiations over Serbian entry start next year, and date of entry negotiations is still unknown, it seems realistic that Serbia will not join the EU by the end of this decade. In that respect, main argument of this article is that Serbian entry to the EU is dependent on the fol¬lowing issues: battling systemic corruption and (organized) crime; relations with Kosovo; and change of political culture.Artykuł stanowi analizę serbskich dążeń do członkostwa w Unii Europejskiej. Uwzględniąc status Serbii jako państwa kandydującego do Unii Europejskiej od marca 2012 r., władze serbskie są zmuszone przeprowadzić niekiedy bolesne reformy. Nadal nieznana jest data wejścia Serbii do Unii Europejskiej, choć jasne pozostaje, że państwo to nie stanie się członkiem UE przed końcem tej dekady. Uwzględniając powyższe, w artykule wskazano, że wejście Serbii do UE uzależnione jest od: skutecznej walki z korupcją i (zorganizowan¹) przestępczością; relacji z Kosowem ; oraz zmiany kultury politycznej

La polyandrie chez les Slaves du Sud

Dordević Tihomir R. La polyandrie chez les Slaves du Sud. In: Revue des études slaves, tome 4, fascicule 1-2, 1924. pp. 101-112

The Construction of the Great Well in Belgrade during the Austrian Rule in the 18th Century

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