Members Of Intestinal Microbiota Research Articles

Antibacterial effect of a diet pill supplement on the human intestinal bacteria

Many people worldwide attempt to lose weight or adopt strategies to control it. Some have resorted to the consumption of commercialized diet pills to achieve this goal. Multiple brands exist without clearly indicating their mechanism of action or adverse effects on human health. This study aims to determine the antibacterial effect of commercial diet pills on members of the intestinal microbiota. Commercialized diet pills were bought from a pharmacy in the North of Lebanon. Broth microdilution test was performed to determine the Minimum Inhibitory Concentrations (MICs) of the aqueous suspension against forty-two isolates distributed into four Enterobacterales species. MIC of the digested form was determined against six different strains. GC-MS analysis was performed to elucidate the components of the diet pill compared to the manufacturer's list. Broth microdilution results revealed that MICs of the diet pill aqueous suspension ranged from 3.9x103-9.76x102 µg/mL for Escherichia coli, Enterobacter spp., and Proteus spp. For Klebsiella species, MIC of carbapenem-resistant isolates reached 1.95x103 µg/mL. The digested form had a significantly lower antibacterial effect compared to the aqueous suspension. GC-MS analysis results corresponded with the list of ingredients provided by the manufacturer. The results showed significant antibacterial activity of a commercial diet pill on different members of the human intestinal microbiota regardless of their resistance profile. Further work is needed to elucidate the antibacterial effect of the digested components to accurately understand their effect on the intestinal microflora and thus on human health.

Патогенетична роль мікрофлори кишечника в розвитку ожиріння

The purpose of the study was to analyze the sources of modern literature of domestic and foreign researchers on the role of intestinal microbiota in the pathogenesis of obesity. Results and discussion. The number of patients with obesity and associated cardio-metabolic disorders such as arterial hypertension, dyslipidemia, coronary heart disease, type 2 diabetes mellitus is constantly increasing. The increase in the prevalence of obesity and metabolic disorders cannot be attributed solely to changes in the human genome, dietary habits, or reduced levels of physical activity. In addition to the generally recognized reasons, one of the factors affecting the microorganism’s energy homeostasis is the intestinal microbiota. Intestinal microbiota is a collection of bacteria that inhabit the gastrointestinal tract. Intestinal microbiota and its active metabolites are involved in intestinal and hepatic gluconeogenesis, in fat homeostasis, in the synthesis of incretin hormones, and influence on the appetite regulation. Short-chain fatty acids are the most important metabolites of intestinal microbiota. Some bacteria of the Firmicutes, Eubacterium rectale/Roseburia phylum and Faecalibacterium prausnitzii and others produce short-chain fatty acids. Short-chain fatty acids perform a detoxifying function, maintain water and electrolyte balance, and participate in immune response processes by reducing the synthesis of pro-inflammatory interleukins. Intestinal microbiota is also considered as one of the potential sources of metabolic endotoxemia formation. The role of endotoxin in the human body is performed by one of the components of the outer membrane of gram-negative bacteria – lipopolysaccharide. It is constantly present in the blood, and at “physiological” concentrations it maintains the balance of the immune system, and “excessive” concentration of lipopolysaccharide in the blood leads to low-grade inflammation, endothelial dysfunction, and other inflammation-associated conditions. The degree of endotoxemia positively correlates with the severity of negative changes in lipid and carbohydrate metabolism. Also, intestinal microbiota can send signals to the central nervous system through the enteric nervous system or through the afferent fibers of the nervus vagus, both directly and through the release of neurotransmitters into the bloodstream. In turn, when transmitting signals from top to bottom, the autonomic nervous system and the hypothalamus-pituitary-adrenal axis affects intestinal microbiota, probably due to changes in the chemical composition of secretions. Conclusion. Members of intestinal microbiota can inhibit the activity of the enzyme adenosine monophosphate-activated protein kinase in muscle and liver, which entails a decrease in fatty acid oxidation and an increase in body fat. As it turned out, almost all known cardiovascular risk factors are to a greater or lesser extent interconnected with the state of the intestinal microbiota, so understanding its role and methods for correcting the composition of the intestinal microbiota can be of great importance in solving important issues in medicine

Prebiotic Isomaltooligosaccharide Provides an Advantageous Fitness to the Probiotic Bacillus subtilis CU1

Bacillus subtilis CU1 is a probiotic strain with beneficial effects on immune health in elderly subjects and diarrhea. Commercialized under spore form, new strategies to improve the germination, fitness and beneficial effects of the probiotic once in the gut have to be explored. For this purpose, functional food ingredients, such as isomaltooligosaccharides (IMOSs), could improve the fitness of Bacillus probiotics. IMOSs are composed of α(1 → 6)- and α(1 → 4)-linked oligosaccharides and are partially indigestible. Dietary IMOSs stimulate beneficial members of intestinal microbiota, but the effect of a combination of IMOSs with probiotics, such as B. subtilis CU1, is unknown. In this study, we evaluate the potential effect of IMOSs in B. subtilis CU1 and identify the metabolic pathways involved. The biochemical analysis of the commercial IMOSs highlights a degree of polymerization (DP) comprised between 1 and 29. The metabolism of IMOSs in CU1 was attributed to an α-glucosidase, secreted in the extracellular compartment one hundred times more than with glucose, and which seems to hydrolyze high DP IMOSs into shorter oligosaccharides (DP1, DP2 and DP3) in the culture medium. Proteomic analysis of CU1 after growth on IMOSs showed a reshaping of B. subtilis CU1 metabolism and functions, associated with a decreased production of lactic acid and acetic acid by two times. Moreover, we show for the first time that IMOSs could improve the germination of a Bacillus probiotic in the presence of bile salts in vitro, with an 8 h reduced lag-time when compared to a glucose substrate. Moreover, bacterial concentration (CFU/mL) was increased by about 1 log in IMOS liquid cultures after 48 h when compared to glucose. In conclusion, the use of IMOSs in association with probiotic B. subtilis CU1 in a synbiotic product could improve the fitness and benefits of the probiotic.

Metformin Influence on the Intestinal Microbiota and Organism of Rats with Metabolic Syndrome.

Metformin is a first-line drug for DM2 treatment and prevention, but its complex effect on impaired glucose tolerance (IGT), including its influence on myocardial resistance to ischemia-reperfusion injury, is not completely studied. We aimed to evaluate the influence of metformin on the intestinal microbiota (IM), metabolism, and functional and morphological characteristics of myocardium in rats with IGT. IGT was modelled in SPF Wistar rats with a high-fat diet and streptozotocin and nicotinamide injection. Rats were divided into three groups: IGT (without treatment), IGT MET (metformin therapy), and CRL (without IGT induction and treatment). IGT group was characterized by: higher body weight, increased serum glucose and total cholesterol levels, atherogenic coefficient, impairment in the functional parameters of the isolated heart during perfusion, and larger myocardium infarction (MI) size in comparison with the CRL group. IM of IGT rats differed from that of CRL: an increase of Bacteroides, Acinetobacter, Akkermansia, Roseburia, and a decrease of Lactobacillus genera representation. Metformin therapy led to the diminishing of metabolic syndrome (MS) symptoms, which correlated with IM restoration, especially with the growth of Akkermansia spp. and decline of Roseburia populations and their influence on other members of IM. The obtained results allow us to consider from a new point of view the expediency of probiotic A. muciniphila use for MS treatment.

BIOTECHNOLOGY OF SOYA MULTI-COMPONENT FUNCTIONAL INGREDIENTS

The materials of the article present analytical and scientific-practical results of research of soy multi-component functional ingredients. Soy extract (or soy milk) is a valuable and cheap source of protein and other nutritious and biologically active components, like lipids, vitamins, mineral elements, isoflavones, flavonoids, saponins etc. But the presence of indigestible oligosaccharides and a bean flavor limit the consumption of soy milk. The soy oligosaccharides are known to be prebiotic for intestinal microbiota, particularly for probiotic microorganisms that hydrolyze them with the enzyme α-galactosidase. Isoflavones are known as phytoestrogens since they are similar to human estrogen in structure and function, and are recommended to prevent many hormonedependent diseases. In soy beans and unfermented soy products, isoflavones are present mainly as biologically inactive glycoside conjugates. Biologically active aglycones of soy isoflavones are substances that are assimilated by human organism from soy products faster and in higher amounts than their corresponding glycosides. The members of intestinal microbiota are predicted to play an important role also in the metabolism and bioavailability of isoflavones since they, synthesizing β-glycosidase, cause hydrolysis of glycoside components, thus releasing the bioavailable and biologically active form of aglycone. In this work, we estimated the potential of some Lactobacillus and Bifidobacterium strains to synthesize α-galactosidase and β-glycosidase, and to reduce respectively the amount of galactooligosaccharides and to convert isoflavones into their active forms, when growing in soy milk. Simultaneously, the profile of soy milk fermentation by the chosen probiotics was studied, as well as the proteolytic activity and accumulation of lactic acid by those probiotics, i. e. the possibility to produce soy-based polyfunctional fermented food products was investigated.

The Utilisation of Acrylamide by Selected Microorganisms Used for Fermentation of Food.

Acrylamide (AA) present in food is considered a harmful compound for humans, but it exerts an impact on microorganisms too. The aim of this study was to evaluate the impact of acrylamide (at conc. 0–10 µg/mL) on the growth of bacteria (Leuconostoc mesenteroides, Lactobacillus acidophilus LA-5) and yeasts (Saccharomyces cerevisiae, Kluyveromyces lactis var. lactis), which are used for food fermentation. Moreover, we decided to verify whether these microorganisms could utilise acrylamide as a nutritional compound. Our results proved that acrylamide can stimulate the growth of L. acidophilus and K. lactis. We have, to the best of our knowledge, reported for the first time that the probiotic strain of bacteria L. acidophilus LA-5 is able to utilise acrylamide as a source of carbon and nitrogen if they lack them in the environment. This is probably due to acrylamide degradation by amidases. The conducted response surface methodology indicated that pH as well as incubation time and temperature significantly influenced the amount of ammonia released from acrylamide by the bacteria. In conclusion, our studies suggest that some strains of bacteria present in milk fermented products can exert additional beneficial impact by diminishing the acrylamide concentration and hence helping to prevent against its harmful impact on the human body and other members of intestinal microbiota.

Update on the toxins of Clostridium perfringens and their actions

Clostridia appeared as a distinct class, approximately 2.7 billion years ago, before the initial formation of oxygen. Clostridium perfringens is widely distributed throughout the environment due to its ability to form spores. Furthermore, it is a member of intestinal microbiota in animals and human. In 2002, the complete genome of C perfringens strain 13 was published. Genomic analysis has revealed that C. perfringens lacks the genetic machinery to produce 13 essential amino acids and it obtains these in vivo via the action of its toxins. Toxins of C perfringens can be divided into major, minor and enterotoxin. C perfringens strains are classified into five toxinotypes (A, B, C, D and E), based on the production of four major toxins. Alpha toxin is the best and most studied major toxin of C perfringens and it was the first bacterial toxin established to possess enzymatic activity. It has haemolytic, necrotic and cytolytic activity, it can lyse platelets and leukocytes and it can damage fibroblasts and muscle cell membranes. Expression of epa gene, which is responsible for the production of alpha toxin by C perfringens, is down-regulated in the normal healthy gut, but it is upregulated to initiate enteric disease in response to an environmental signal. C perfringens appears to be regulated in a quorum sensing manner, using oligopeptides, AI-2 or both, to regulate expression of the epa gene, and thus the synthesis of alpha toxin. Beta toxin is recognized as an important agent in necrotic enteritis of humans and it is the second most lethal C. perfringens toxin following epsilon toxin. Beta toxin is a membrane spanning protein that oligomerizes to form channels in susceptible cells or it primarily acts as a neurotoxin. Epsilon toxin is the most potent of the C. perfringens toxins and the third most potent neurotoxin from the Clostridium spp., following botulinum and tetanus toxins. Epsilon toxin of C perfringens type D causes enterotoxaemia and pulpy kidneys disease of lambs. Iota toxin causes disruption of the actin cytoskeleton and cell barrier integrity and it is the less toxic of the major toxins of C perfringens. Although C perfringens enterotoxin is not classified as one of the major toxins of C perfringens, it is the third most common cause of food poisoning in industrialized nations. It is not secreted by the cells of growing bacteria, but it is released only with the sporulation of C perfringens. Not all strains of C perfringens carry the epe gene, which is responsible for the production of enterotoxin. Theta toxin is a pore-forming cytolysin that can lyse red blood cells. It is produced by all types of C perfringens. Together with alpha-toxin, theta-toxin modulates the host inflammatory response. ß2 toxin is a pore forming toxin which is involved in necrotic enteritis of swine and horse, in haemorragic enteritis of bovine in diarrhea cases of dogs and along with enterotoxin in diarrhea cases of humans. Recently, -NetB, a novel toxin that is associated with broiler necrotic enteritis, has been described. The mechanism of its action seems to involve the formation of small hydrophilic pores. Other toxins of C. perfringens include λ-toxin, ô-toxin, μ-toxin, v-toxin, κ-toxin, a-clostripain like protease and neuraminidase/sialidase. These toxins can act as enzymes, while many of them can act synergically or supplementally with major pore forming toxins. Potentially, C. perfringens might produce more toxins, which have not been identified. Finally, the actions of C. perfringens toxins, major or minor, in some diseases have not been figured out.

Influence of the human intestinal microbiome on obesity and metabolic dysfunction.

Recent studies have suggested that there may be a strong link between the gut microbiota, energy extraction and body metabolism. Evidence is accumulating that the intestinal microbiota, in addition to other major factors such as diet and host genetics, contributes to obesity, metabolic dysfunction and diabetes. Both preclinical experimental and human studies have shown that obesity and metabolic dysfunction are characterized by a profound dysbiosis. Several human metagenome-wide association studies have demonstrated highly significant correlations of certain members of intestinal microbiota with obesity and type 2 diabetes. In addition dietary factors that substantially affect microbial composition, microbiota disruption, and the consequence of early-life antibiotic use, may contribute to childhood obesity and metabolic dysfunction. Further evidence for an association between microbiota and metabolic dysfunction has been derived from studies in pregnancy demonstrating that major gut microbial shifts occur during pregnancy thereby affecting host metabolism. In particular, the high rate of obesity following caesarean section could be partially explained by functional alterations in the intestinal microbiota. Obesity and associated metabolic dysfunction emerge from disturbed interactions between the intestinal microbiota, dietary changes and host immune functions. A better understanding of this relationship might lead to better therapies for human metabolic and inflammatory diseases in the future.