Comparison of microbial communities and the profile of sulfate-reducing bacteria in patients with ulcerative colitis and their association with bowel diseases: a pilot study.

Considerable evidence has accumulated regarding the molecular relationship between gut microbiota (GM) composition and the onset (clinical presentation and prognosis of ulcerative colitis (UC)). In addition, it is well documented that short-chain fatty acid (SCFA)-producing bacteria may play a fundamental role in maintaining an anti-inflammatory intestinal homeostasis, but sulfate- and sulfite reducing bacteria may be responsible for the production of toxic metabolites, such as hydrogen sulfide and acetate. Hence, the present study aimed to assess the GM composition - focusing on sulfate-reducing bacteria (SRB) - in patients with severe, severe-active and moderate UC. Each one of the six enrolled patients provided two stool samples in the following way: one sample was cultivated in a modified SRB-medium before 16S rRNA sequencing and the other was not cultivated. Comparative phylogenetic analysis was conducted on each sample. Percentage of detected gut microbial genera showed considerable variation based on the patients' disease severity and cultivation in the SRB medium. In detail, samples without cultivation from patients with moderate UC showed a high abundance of the genera Bacteroides, Bifidobacterium and Ruminococcus, but after SRB cultivation, the dominant genera were Bacteroides, Klebsiella and Bilophila. On the other hand, before SRB cultivation, the main represented genera in patients with severe UC were Escherichia-Shigella, Proteus, Methanothermobacter and Methanobacterium. However, after incubation in the SRB medium Bacteroides, Proteus, Alistipes and Lachnoclostridium were predominant. Information regarding GM compositional changes in UC patients may aid the development of novel therapeutic strategies (e.g., probiotic preparations containing specific bacterial strains) to counteract the mechanisms of virulence of harmful bacteria and the subsequent inflammatory response that is closely related to the pathogenesis of inflammatory bowel diseases.

Bafilomycin A1 Molecular Effect on ATPase Activity of Subcellular Fraction of Human Colorectal Cancer and Rat Liver.

Bafilomycin A1 inhibits V-type H+ ATPases on the molecular level, which acidifies endo-lysosomes. The main objective of the study was to assess the effect of bafilomycin A1 on Ca2+ content, NAADP-induced Ca2+ release, and ATPase activity in rat hepatocytes and human colon cancer samples. Chlortetracycline (CTC) was used for a quantitative measure of stored calcium in permeabilized rat hepatocytes. ATPase activity was determined by orthophosphate content released after ATP hydrolysis in subcellular post-mitochondrial fraction obtained from rat liver as well as from patients' samples of colon mucosa and colorectal cancer samples. In rat hepatocytes, bafilomycin A1 decreased stored Ca2+ and prevented the effect of NAADP on stored Ca2+. This effect was dependent on EGTA-Ca2+ buffers in the medium. Bafilomycin A1 significantly increased the activity of Ca2+ ATPases of endoplasmic reticulum (EPR), but not plasma membrane (PM) Ca2+ ATPases in rat liver. Bafilomycin A1 also prevented the effect of NAADP on these pumps. In addition, bafilomycin A1 reduced Na+/K+ ATPase activity and increased basal Mg2+ ATPase activity in the subcellular fraction of rat liver. Concomitant administration of bafilomycin A1 and NAADP enhanced these effects. Bafilomycin A1 increased the activity of the Ca2+ ATPase of EPR in the subcellular fraction of normal human colon mucosa and also in colon cancer tissue samples. In contrast, it decreased Ca2+ ATPase PM activity in samples of normal human colon mucosa and caused no changes in colon cancer. Bafilomycin A1 decreased Na+/K+ ATPase activity and increased basal Mg2+ ATPase activity in normal colon mucosa samples and in human colon cancer samples. It can be concluded that bafilomycin A1 targets NAADP-sensitive acidic Ca2+ stores, effectively modulates ATPase activity, and assumes the link between acidic stores and EPR. Bafilomycin A1 may be useful for cancer therapy.

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 (Km) during exponential and stationary phases are noticeable between D. piger Vib-7 and D. orale Rod-9; D. orale Rod-9 showed much higher Km (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.

Edible/Biodegradable Packaging with the Addition of Spent Coffee Grounds Oil.

BACKGROUND: Following petroleum, coffee ranks as the second most extensively exchanged commodity worldwide. The definition of spent coffee ground (SCG) can be outlined as the waste generated after consuming coffee. The aims of the study are to produce edible/biodegradable packaging with the addition of spent coffee grounds (SCG) oil and to investigate how this fortification can affect chemical, textural, and solubility properties of experimentally produced films. METHODS: The produced films were based on κ-carrageenan and pouring-drying techniques in petri dishes. Two types of emulsifiers were used: Tween 20 and Tween 80. The films were analyzed by antioxidant and textural analysis, and their solubility was also tested. RESULTS: Edible/biodegradable packaging samples produced with the addition of SCG oil showed higher (p < 0.05) antioxidant capacity in comparison with control samples produced without the addition of SCG oil. The results of the research showed that the fortification of edible/biodegradable packaging with the addition of SCG oil changed significantly (p < 0.05) both chemical and physical properties of the films. CONCLUSIONS: Based on the findings obtained, it was indicated that films manufactured utilizing SCG oil possess considerable potential to serve as an effective and promising material for active food packaging purposes.

Sulfur content in foods and beverages and its role in human and animal metabolism: A scoping review of recent studies.

Sulfur is a vital element that all living things require, being a component of proteins and other bio-organic substances. The various kinds and varieties of microbes in nature allow for the transformation of this element. It also should be emphasized that volatile sulfur compounds are typically present in food in trace amounts. Life cannot exist without sulfur, yet it also poses a potential health risk. The colon's sulfur metabolism, which is managed by eukaryotic cells, is much better understood than the S metabolism in gastrointestinal bacteria. Numerous additional microbial processes are anticipated to have an impact on the content and availability of sulfated compounds, as well as intestinal S metabolism. Hydrogen sulfide is the sulfur derivative that has attracted the most attention in relation to colonic health, but it is still unclear whether it is beneficial or harmful. Several lines of evidence suggest that sulfate-reducing bacteria or exogenous hydrogen sulfide may be the root cause of intestinal ailments, including inflammatory bowel diseases and colon cancer. Taurine serves a variety of biological and physiological purposes, including roles in inflammation and protection, additionally, low levels of taurine can be found in bodily fluids, and taurine is the primary sulfur component present in muscle tissue (serum and urine). The aim of this scoping review was to compile data from the most pertinent scientific works about S compounds' existence in food and their metabolic processes. The importance of S compounds in various food products and how these compounds can impact metabolic processes are both stressed in this paper.

Photoautotrophic removal of hydrogen sulfide from biogas using purple and green sulfur bacteria.

Biogas desulfurization based on anoxygenic photosynthetic processes represents an alternative to physicochemical technologies, decreasing the risk of O2 and N2 contamination. This work aimed at assessing the potential of Allochromatium vinosum and Chlorobium limicola for biogas desulfurization under different light intensities (10 and 25 klx) and H2S concentrations (1 %, 1.5 % and 2 %) in batch photobioreactors. In addition, the influence of rising biogas flow rates (2.9, 5.8 and 11.5 L d-1 in stage I, II and III, respectively) on the desulfurization performance in a 2.3 L photobioreactor utilizing C. limicola under continuous mode was assessed. The light intensity of 25 klx negatively influenced the growth of A. vinosum and C. limicola, resulting in decreased H2S removal capacity. An increase in H2S concentrations resulted in higher volumetric H2S removal rates in C. limicola (2.9-5.3 mg L-1 d-1) tests compared to A. vinosum (2.4-4.6 mg L-1 d-1) tests. The continuous photobioreactor completely removed H2S from biogas in stage I and II. The highest flow rate in stage III induced a deterioration in the desulfurization activity of C. limicola. Overall, the high H2S tolerance of A. vinosum and C. limicola supports their use in H2S desulfurization from biogas.

Microbiological insight into various underground gas storages in Vienna Basin focusing on methanogenic Archaea.

In recent years, there has been a growing interest in extending the potential of underground gas storage (UGS) facilities to hydrogen and carbon dioxide storage. However, this transition to hydrogen storage raises concerns regarding potential microbial reactions, which could convert hydrogen into methane. It is crucial to gain a comprehensive understanding of the microbial communities within any UGS facilities designated for hydrogen storage. In this study, underground water samples and water samples from surface technologies from 7 different UGS objects located in the Vienna Basin were studied using both molecular biology methods and cultivation methods. Results from 16S rRNA sequencing revealed that the proportion of archaea in the groundwater samples ranged from 20 to 58%, with methanogens being the predominant. Some water samples collected from surface technologies contained up to 87% of methanogens. Various species of methanogens were isolated from individual wells, including Methanobacterium sp., Methanocalculus sp., Methanolobus sp. or Methanosarcina sp. We also examined water samples for the presence of sulfate-reducing bacteria known to be involved in microbially induced corrosion and identified species of the genus Desulfovibrio in the samples. In the second part of our study, we contextualized our data by comparing it to available sequencing data from terrestrial subsurface environments worldwide. This allowed us to discern patterns and correlations between different types of underground samples based on environmental conditions. Our findings reveal presence of methanogens in all analyzed groups of underground samples, which suggests the possibility of unintended microbial hydrogen-to-methane conversion and the associated financial losses. Nevertheless, the prevalence of methanogens in our results also highlights the potential of the UGS environment, which can be effectively leveraged as a bioreactor for the conversion of hydrogen into methane, particularly in the context of Power-to-Methane technology.

Molecular Research of Lipid Peroxidation and Antioxidant Enzyme Activity of Comamonas testosteroni Bacterial Cells under the Hexachlorobenzene Impact.

The species of Comamonas testosteroni is the most common human pathogen of the genus, which can be associated with acute appendicitis, infections of the bloodstream, the peritoneal cavity, cerebrospinal fluid, inflammatory bowel disease, and in general, bacteremia. According to the literature, Comamonas testosteroni has destructive activity to a wide range of toxic chemical compounds, including chlorobenzenes. The specified strains were isolated from the soil of the organochlorine waste landfill, where hexachlorobenzene (HCB) was predominant. These strains were expected to be capable of degrading HCB. Microbiological (bacterial enrichment and cultivating, bacterial biomass obtaining), molecular biology, biochemical (enzymatic activities, malondialdehyde measuring, peroxidation lipid products measuring), and statistical methods were carried out in this research. The reaction of both strains (UCM B-400 and UCM B-401) to the hexachlorobenzene presence differed in the content of diene and triene conjugates and malondialdehyde, as well as different catalase and peroxidase activity levels. In terms of primary peroxidation products, diene conjugates were lower, except conditions with 20 mg/L HCB, where these were higher up to two times, than the pure control. Malondialdehyde in strain B-400 cells decreased up to five times, in B-401, but increased up to two times, compared to the pure control. Schiff bases in strain B-400 cells were 2-3 times lower than the pure control. However, in B-401 cells Schiff bases under higher HCB dose were in the same level with the pure control. Catalase activity was 1.5 times higher in all experimental variants, compared to the pure control (in the strain B-401 cells), but in the B-400 strain, cells were 2 times lower, compared to the pure control. The response of the two strains to hexachlorobenzene was similar only in peroxidase activity terms, which was slightly higher compared to the pure control. The physiological response of Comamonas testosteroni strains to hexachlorobenzene has a typical strain reaction. The physiological response level of these strains to hexachlorobenzene confirms its tolerance, and indirectly, the ability to destroy the specified toxic compound.

No Correlation between Biofilm-Forming Capacity and Antibiotic Resistance in Environmental Staphylococcus spp.: In Vitro Results.

The production of biofilms is a critical factor in facilitating the survival of Staphylococcus spp. in vivo and in protecting against various environmental noxa. The possible relationship between the antibiotic-resistant phenotype and biofilm-forming capacity has raised considerable interest. The purpose of the study was to assess the interdependence between biofilm-forming capacity and the antibiotic-resistant phenotype in 299 Staphylococcus spp. (S. aureus n = 143, non-aureus staphylococci [NAS] n = 156) of environmental origin. Antimicrobial susceptibility testing and detection of methicillin resistance (MR) was performed. The capacity of isolates to produce biofilms was assessed using Congo red agar (CRA) plates and a crystal violet microtiter-plate-based (CV-MTP) method. MR was identified in 46.9% of S. aureus and 53.8% of NAS isolates (p > 0.05), with resistance to most commonly used drugs being significantly higher in MR isolates compared to methicillin-susceptible isolates. Resistance rates were highest for clindamycin (57.9%), erythromycin (52.2%) and trimethoprim-sulfamethoxazole (51.1%), while susceptibility was retained for most last-resort drugs. Based on the CRA plates, biofilm was produced by 30.8% of S. aureus and 44.9% of NAS (p = 0.014), while based on the CV-MTP method, 51.7% of S. aureus and 62.8% of NAS were identified as strong biofilm producers, respectively (mean OD570 values: S. aureus: 0.779±0.471 vs. NAS: 1.053±0.551; p < 0.001). No significant differences in biofilm formation were observed based on MR (susceptible: 0.824 ± 0.325 vs. resistant: 0.896 ± 0.367; p = 0.101). However, pronounced differences in biofilm formation were identified based on rifampicin susceptibility (S: 0.784 ± 0.281 vs. R: 1.239 ± 0.286; p = 0.011). The mechanistic understanding of the mechanisms Staphylococcus spp. use to withstand harsh environmental and in vivo conditions is crucial to appropriately address the therapy and eradication of these pathogens.

ATPase Activity of the Subcellular Fractions of Colorectal Cancer Samples under the Action of Nicotinic Acid Adenine Dinucleotide Phosphate.

In tumor cells with defects in apoptosis, autophagy allows prolonged survival. Autophagy leads to an accumulation of damaged mitochondria by autophagosomes. An acidic environment is maintained in compartments of cells, such as autophagosomes, late endosomes, and lysosomes; these organelles belong to the "acid store" of the cells. Nicotinic acid adenine dinucleotide phosphate (NAADP) may affect the release of Ca2+ from these organelles and affect the activity of Ca2+ ATPases and other ion transport proteins. Recently, a growing amount of evidence has shown that the variations in the expression of calcium channels or pumps are associated with the occurrence, disease-presentation, and the prognosis of colorectal cancer. We hypothesized that activity of ATPases in cancer tissue is higher because of intensive energy metabolism of tumor cells. The aim of our study was to ascertain the effect of NAADP on ATPase activity on tissue samples of colorectal cancer patients' and healthy individuals. We tested the effect of NAADP on the activity of Na+/K+ ATPase; Ca2+ ATPase of endoplasmic reticulum (EPR) and plasma membrane (PM) and basal ATPase activity. Patients' colon mucus cancer samples were obtained during endoscopy from cancer and healthy areas (control) of colorectal mucosa of the same patients. Results. The mean activity of Na+/K+ pump in samples of colorectal cancer patients (n = 5) was 4.66 ± 1.20 µmol Pi/mg of protein per hour, while in control samples from healthy tissues of the same patient (n = 5) this value was 3.88 ± 2.03 µmol Pi/mg of protein per hour. The activity of Ca2+ ATPase PM in control samples was 6.42 ± 0.63 µmol Pi/mg of protein per hour and in cancer -8.50 ± 1.40 µmol Pi/mg of protein per hour (n = 5 pts). The mean activity of Ca2+ ATPase of EPR in control samples was 7.59 ± 1.21 µmol Pi/mg versus 7.76 ± 0.24 µmol Pi/mg in cancer (n = 5 pts). Basal ATPase activity was 3.19 ± 0.87 in control samples versus 4.79 ± 1.86 µmol Pi/mg in cancer (n = 5 pts). In cancer samples, NAADP reduced the activity of Na+/K+ ATPase by 9-times (p < 0.01) and the activity of Ca2+ ATPase EPR about 2-times (p < 0.05). NAADP caused a tendency to decrease the activity of Ca2+ ATPase of PM, but increased basal ATPase activity by 2-fold vs. the mean of this index in cancer samples without the addition of NAADP. In control samples NAADP caused only a tendency to decrease the activities of Na+/K+ ATPase and Ca2+ ATPase EPR, but statistically decreased the activity of Ca2+ ATPase of PM (p < 0.05). In addition, NAADP caused a strong increase in basal ATPase activity in control samples (p < 0.01). Conclusions: We found that the activity of Na+/K+ pump, Ca2+ ATPase of PM and basal ATPase activity in cancer tissues had a strong tendency to be higher than in the controls. NAADP caused a decrease in the activities of Na+/K+ ATPase and Ca2+ ATPase EPR in cancer samples and increased basal ATPase activity. In control samples, NAADP decreased Ca2+ ATPase of PM and increased basal ATPase activity. These data confirmed different roles of NAADP-sensitive "acidic store" (autophagosomes, late endosomes, and lysosomes) in control and cancer tissue, which hypothetically may be connected with autophagy role in cancer development. The effect of NAADP on decreasing the activity of Na+/K+ pump in cancer samples was the most pronounced, both numerically and statistically. Our data shows promising possibilities for the modulation of ion-transport through the membrane of cancer cells by influence on the "acidic store" (autophagosomes, late endosomes and lysosomes) as a new approach to the treatment of colorectal cancer.

Molecular Physiology of Anaerobic Phototrophic Purple and Green Sulfur Bacteria.

There are two main types of bacterial photosynthesis: oxygenic (cyanobacteria) and anoxygenic (sulfur and non-sulfur phototrophs). Molecular mechanisms of photosynthesis in the phototrophic microorganisms can differ and depend on their location and pigments in the cells. This paper describes bacteria capable of molecular oxidizing hydrogen sulfide, specifically the families Chromatiaceae and Chlorobiaceae, also known as purple and green sulfur bacteria in the process of anoxygenic photosynthesis. Further, it analyzes certain important physiological processes, especially those which are characteristic for these bacterial families. Primarily, the molecular metabolism of sulfur, which oxidizes hydrogen sulfide to elementary molecular sulfur, as well as photosynthetic processes taking place inside of cells are presented. Particular attention is paid to the description of the molecular structure of the photosynthetic apparatus in these two families of phototrophs. Moreover, some of their molecular biotechnological perspectives are discussed.

Anoxygenic Photosynthesis in Photolithotrophic Sulfur Bacteria and Their Role in Detoxication of Hydrogen Sulfide.

Hydrogen sulfide is a toxic compound that can affect various groups of water microorganisms. Photolithotrophic sulfur bacteria including Chromatiaceae and Chlorobiaceae are able to convert inorganic substrate (hydrogen sulfide and carbon dioxide) into organic matter deriving energy from photosynthesis. This process takes place in the absence of molecular oxygen and is referred to as anoxygenic photosynthesis, in which exogenous electron donors are needed. These donors may be reduced sulfur compounds such as hydrogen sulfide. This paper deals with the description of this metabolic process, representatives of the above-mentioned families, and discusses the possibility using anoxygenic phototrophic microorganisms for the detoxification of toxic hydrogen sulfide. Moreover, their general characteristics, morphology, metabolism, and taxonomy are described as well as the conditions for isolation and cultivation of these microorganisms will be presented.

Microscopic Methods for Identification of Sulfate-Reducing Bacteria from Various Habitats.

This paper is devoted to microscopic methods for the identification of sulfate-reducing bacteria (SRB). In this context, it describes various habitats, morphology and techniques used for the detection and identification of this very heterogeneous group of anaerobic microorganisms. SRB are present in almost every habitat on Earth, including freshwater and marine water, soils, sediments or animals. In the oil, water and gas industries, they can cause considerable economic losses due to their hydrogen sulfide production; in periodontal lesions and the colon of humans, they can cause health complications. Although the role of these bacteria in inflammatory bowel diseases is not entirely known yet, their presence is increased in patients and produced hydrogen sulfide has a cytotoxic effect. For these reasons, methods for the detection of these microorganisms were described. Apart from selected molecular techniques, including metagenomics, fluorescence microscopy was one of the applied methods. Especially fluorescence in situ hybridization (FISH) in various modifications was described. This method enables visual identification of SRB, determining their abundance and spatial distribution in environmental biofilms and gut samples.

Intestinal Microbiota and Perspectives of the Use of Meta-Analysis for Comparison of Ulcerative Colitis Studies.

Meta-analysis is a statistical process summarizing comparable data from a number of scientific papers. The use of meta-analysis in microbiology allows decision-making that has an impact on public health policy. It can happen that the primary researches come to different conclusions, although these are targeted with the same research question. It is, therefore, inevitable to have the means to systematically evaluate information and compare research results. Ulcerative colitis together with Crohn's disease are among the two main inflammatory bowel diseases. This chronic disease of the gastrointestinal tract, with an as yet unclear etiology, is presented by an uncontrolled inflammatory immune response in genetically predisposed individuals to as yet undefined environmental factors in interaction with the intestinal microbiota itself. In patients with ulcerative colitis (UC), changes in the composition and relative abundance of microorganisms could be observed. Sulfate-reducing bacteria (SRB), which commonly occur in the large intestine as part of the commensal microbiota of animals and humans involved in the pathogenesis of the disease, have been shown to occur. SRB are anaerobic organisms affecting short-chain fatty acid metabolism. This work outlines the perspectives of the use of meta-analysis for UC and changes in the representation of intestinal organisms in these patients.

Possible synergy effect of hydrogen sulfide and acetate produced by sulfate-reducing bacteria on inflammatory bowel disease development.

INTRODUCTION: Increased numbers of sulfate-reducing bacteria (SRB) are often found in the feces of people and animals with inflammatory bowel disease. The final products of their metabolism are hydrogen sulfide and acetate, which are produced during dissimilatory sulfate reduction process. OBJECTIVES: The aim of the study was to monitor processes concerning sulfate reduction microbial metabolisms, including: the main microbial genera monitoring and their hydrogen sulfide production in the intestines of healthy and not healthy individuals, phylogenetic analysis of SRB isolates, cluster analysis of SRB physiological and biochemical parameters, SRB growth kinetic parameters calculation, same as the application of the two-factor dispersion analysis for finding relationship between SRB biomass accumulation, temperature and pH. Feces samples from healthy people and patients with colitis were used for isolation of sulfate-reducing microbial communities. METHODS: Microbiological, biochemical, biophysical, molecular biology methods, and statistical processing of the results have been used for making an evaluation of gained results. RESULTS: Two dominant SRB morphotypes differed in colony size and quantitative ratio in the feces of healthy and colitis patients were observed and identified. In the feces of healthy people, 93% of SRB of morphotype I prevailed (Desulfovibrio) while morphotype II made only 7% (Desulfomicrobium); in the feces of patients with colitis, the ratio of these morphotypes was 99:1, respectively. Hydrogen sulfide concentrations are also higher in the feces of people with colitis and certain synergy effects exist among acetate produced by SRB. CONCLUSIONS: The study results brought important findings concerning colony environments with developed colitis and these findings can lead to the development of possible risk indicators of ulcerative colitis prevalence.

Hydrogen sulfide toxicity in the gut environment: Meta-analysis of sulfate-reducing and lactic acid bacteria in inflammatory processes.

BACKGROUND: Hydrogen sulfide is the final product of sulfate-reducing bacteria metabolism. Its high concentration in the gut can affect adversely bowel environment and intestinal microbiota by toxicity and pH lowering. AIM OF REVIEW: The aim of the review was to give observations related to the properties of bacterial communities inhabiting the gut, with the emphasis on sulfate-reducing bacteria and lactic acid bacteria. KEY SCIENTIFIC CONCEPTS OF REVIEW: The conduction of meta-analysis was another goal, since it gave statistical observation of the relevant studies. The review literature consisted of more than 160 studies, published from 1945 to 2019. Meta-analysis included 16 studies and they were chosen from the Web of Science database. The systematic review gave important information about the development of gut inflammation, with emphasis on sulfate-reducing and lactic acid bacteria. Oppositely from sulfate-reducing bacteria, probiotic properties of lactic acid bacteria are effective inhibitors against inflammatory bowel disease development, including ulcerative colitis. These facts were confirmed by the conducted meta-analysis. The results and observations gained from the systematic review represent the emphasized importance of gut microbiota for bowel inflammation. On the other side, it should be stated that more studies in the future will provide even better confirmations.

Sulfate-Reducing Bacteria of the Oral Cavity and Their Relation with Periodontitis-Recent Advances.

The number of cases of oral cavity inflammation in the population has been recently increasing, with periodontitis being the most common disease. It is caused by a change in the microbial composition of the biofilm in the periodontal pockets. In this context, an increased incidence of sulfate-reducing bacteria (SRB) in the oral cavity has been found, which are a part of the common microbiome of the mouth. This work is devoted to the description of the diversity of SRB isolated from the oral cavity. It also deals with the general description of periodontitis in terms of manifestations and origin. It describes the ability of SRB to participate in its development, although their effect on periodontal inflammation is not fully understood. The production of hydrogen sulfide as a cytochrome oxidase inhibitor may play a role in the etiology. A meta-analysis was conducted based on studies of the occurrence of SRB in humans.

Evaluation of Physiological Parameters of Intestinal Sulfate-Reducing Bacteria Isolated from Patients Suffering from IBD and Healthy People.

BACKGROUND: Inflammatory bowel diseases (IBDs) are multifactorial illnesses of the intestine, to which microorganisms are contributing. Among the contributing microorganisms, sulfate-reducing bacteria (SRB) are suggested to be involved in the process of bowel inflammation due to the production of hydrogen sulfide (H2S) by dissimilatory sulfate reduction. The aims of our research were to physiologically examine SRB in fecal samples of patients with IBD and a control group, their identification, the study of the process of dissimilatory sulfate reduction (sulfate consumption and H2S production) and biomass accumulation. Determination of biogenic elements of the SRB and evaluation of obtained parameters by using statistical methods were also included in the research. The material for the research consisted of 14 fecal samples, which was obtained from patients and control subjects. METHODS: Microscopic techniques, microbiological, biochemical, biophysical methods and statistical analysis were included. RESULTS: Colonies of SRB were isolated from all the fecal samples, and subsequently, 35 strains were obtained. Vibrio-shaped cells stained Gram-negative were dominant in all purified studied strains. All strains had a high percentage of similarity by the 16S rRNA gene with deposited sequences in GenBank of Desulfovibrio vulgaris. Cluster analysis of sulfate reduction parameters allowed the grouping of SRB strains. Significant (p < 0.05) differences were not observed between healthy individuals and patients with IBD with regard to sulfate reduction parameters (sulfate consumption, H2S and biomass accumulation). Moreover, we found that manganese and iron contents in the cell extracts are higher among healthy individuals in comparison to unhealthy individuals that have an intestinal bowel disease, especially ulcerative colitis. CONCLUSIONS: The observations obtained from studying SRB emphasize differences in the intestinal microbial processes of healthy and unhealthy people.

Adenosine-5'-Phosphosulfate- and Sulfite Reductases Activities of Sulfate-Reducing Bacteria from Various Environments.

A comparative study of the kinetic characteristics (specific activity, initial and maximum rate, and affinity for substrates) of key enzymes of assimilatory sulfate reduction (APS reductase and dissimilatory sulfite reductase) in cell-free extracts of sulphate-reducing bacteria (SRB) from various biotopes was performed. The material for the study represented different strains of SRB from various ecotopes. Microbiological (isolation and cultivation), biochemical (free cell extract preparation) and chemical (enzyme activity determination) methods served in defining kinetic characteristics of SRB enzymes. The determined affinity data for substrates (i.e., sulfite) were 10 times higher for SRB strains isolated from environmental (soil) ecotopes than for strains from the human intestine. The maximum rate of APS reductase reached 0.282-0.862 µmol/min×mg-1 of protein that is only 10 to 28% higher than similar initial values. The maximum rate of sulfite reductase for corrosive relevant collection strains and SRB strains isolated from heating systems were increased by 3 to 10 times. A completely different picture was found for the intestinal SRB Vmax in the strains Desulfovibrio piger Vib-7 (0.67 µmol/min × mg-1 protein) and Desulfomicrobium orale Rod-9 (0.45 µmol/min × mg-1 protein). The determinant in the cluster distribution of SRB strains is the activity of the terminal enzyme of dissimilatory sulfate reduction-sulfite reductase, but not APS reductase. The data obtained from the activity of sulfate reduction enzymes indicated the adaptive plasticity of SRB strains that is manifested in the change in enzymatic activity.

The Characterization of Enterococcus Genus: Resistance Mechanisms and Inflammatory Bowel Disease.

The constantly growing bacterial resistance against antibiotics is recently causing serious problems in the field of human and veterinary medicine as well as in agriculture. The mechanisms of resistance formation and its preventions are not well explored in most bacterial genera. The aim of this review is to analyse recent literature data on the principles of antibiotic resistance formation in bacteria of the Enterococcus genus. Furthermore, the habitat of the Enterococcus genus, its pathogenicity and pathogenicity factors, its epidemiology, genetic and molecular aspects of antibiotic resistance, and the relationship between these bacteria and bowel diseases are discussed. So-called VREfm - vancomycin resistant Enterococcus faecium and its currently rapidly growing resistance as well as the significance of these bacteria in nosocomial diseases is described.