Human GIT Research Articles

Comprehensive physiological and genomic characterization of a potential probiotic strain, Lactiplantibacillus plantarum ILSF15, isolated from the gut of tribes of Odisha, India

Characterizing probiotic features of organisms isolated from diverse environments can lead to the discovery of novel strains with promising functional features and health attributes. The present study attempts to characterize a novel probiotic strain isolated from the gut of the tribal population of Odisha, India. Based on 16S rRNA-based phylogeny, the strain was identified as a species of the Lactiplantibacillus genus and was named Lactiplantibacillus plantarum strain ILSF15. The current investigation focuses on elucidating this strain’s genetic and physiological properties associated with probiotic attributes such as biosafety risk, host adaptation/survival traits, and beneficial functional features. The novel strain was observed, in vitro, exhibiting features such as acid/bile tolerance, adhesion to the host enteric epithelial cells, cholesterol assimilation, and pathogen exclusion, indicating its ability to survive the harsh environment of the human GIT and resist the growth of harmful microorganisms. Additionally, the L. plantarum ILSF15 strain was found to harbor genes associated with the metabolism and synthesis of various bioactive molecules, including amino acids, carbohydrates, lipids, and vitamins, highlighting the organism’s ability to efficiently utilize diverse resources and contribute to the host’s nutrition and health. Several genes involved in host adaptation/survival strategies and host-microbe interactions were also identified from the ILSF15 genome. Moreover, L. plantarum strains, in general, were found to have an open pangenome characterized by high genetic diversity and the absence of specific lineages associated with particular habitats, signifying its versatile nature and potential applications in probiotic and functional food industries.

Utilization of lactobacilli extracts as antibacterial agent and to induce colorectal cancer cells apoptosis: Application in white soft cheese

Food-borne illnesses certainly increase the risk of developing colon cancer. Due to the de-functionalization of the gut microbiota and host-microbe interactions caused by the preponderance of infectious pathogens, sensitive host cells are more likely to develop mutations. The current research utilized some bio-protective lactobacilli to clarify the metabolic basis of human GIT protection from both anti-pathogenic and anti-cancer views. Both cells and methanolic extracts of Lactoplantibacillus plantarum (LP), Lactobacillus acidophilus (AC), and Lactobacillus rhamnosus GG (GG) were evaluated. The extracts were evaluated for their components by Liquid chromatography–mass spectrometry (LC–MS). The antimicrobial activity of all extracts was determined. A Lactobacillus acidophilus-based extract had the greatest zones of inhibition against all indicator pathogens. Upon co-culturing with pathogens, Lactoplantibacillus plantarum (LP) achieved the maximum reduction percentage of all pathogenic populations. Further LC/MS-based metabolic profiling of extracts showed various biologically active compounds that are thought to be the key health-promoting agents. It was noticed that the IC50 values of HCT 116 cell line upon AC, GG, and LP treatments were 65.897 μg/mL, 79.139 μg/mL, and 71.681 μg/mL, respectively when compared by Raloxifene (RX). Lactobacillus acidophilus (AC) recorded the lowest IC50 (52.053 g/mL) and the highest cytotoxic fold change in Caco-2 cells. Generally, all lactobacilli extracts induced Caco-2 cell apoptosis in a sensitive manner compared to HCT 116 cells by inhibiting cancerous proliferation and inducing nitric oxide release. When various Lactobacilli strains were applied in-situ to white soft cheese, Lactobacillus acidophilus (AC) demonstrated no growth for either bacterial pathogens or spoilage fungi towards the end of the storage time.

Effects of Pectin on Intestinal Microbiota and Human Health

Gut microbes are important players in human metabolism and their genomes are abundant in genes that regulate the metabolism of SFCAs, methane, amino acids, and carbohydrates. Pectin is a water-soluble dietary fiber, an abundant heteropolysaccharide in the main and intermediate cellular lamellae of plant cell walls. Pectin is degraded by a varied group of microorganisms residing in the human gut, which depolymerize pectin by secreting both cell-bound and extracellular enzymes to produce monosaccharides. The pectin fermentation degradation pathway is the main mechanism for the degradation of carbohydrates that cannot be digested in human GIT, and the end products include SCFAs, ethanol, CO2 and H2. The makeup of intestinal microbiota is impacted by these products. Additionally, the effect of pectin on intestinal microbial fractions is related to the structure of pectin, the intestinal environment and the degree of pectin esterification. Moreover, pectin itself and pectin degradation products contribute to human health by influencing intestinal microorganisms. Pectin is effective in modifying allergies to sensitization, reducing body composition and has a preventive effect on type I diabetes.

Comparative Genomics of Lactiplantibacillus plantarum: Insights Into Probiotic Markers in Strains Isolated From the Human Gastrointestinal Tract and Fermented Foods.

Lactiplantibacillus (Lpb.) plantarum is a versatile species commonly found in a wide variety of ecological niches including dairy products and vegetables, while it may also occur as a natural inhabitant of the human gastrointestinal tract. Although Lpb. plantarum strains have been suggested to exert beneficial properties on their host, the precise mechanisms underlying these microbe–host interactions are still obscure. In this context, the genome-scale in silico analysis of putative probiotic bacteria represents a bottom–up approach to identify probiotic biomarkers, predict desirable functional properties, and identify potentially detrimental antibiotic resistance genes. In this study, we characterized the bacterial genomes of three Lpb. plantarum strains isolated from three distinct environments [strain IMC513 (from the human GIT), C904 (from table olives), and LT52 (from raw-milk cheese)]. A whole-genome sequencing was performed combining Illumina short reads with Oxford Nanopore long reads. The phylogenomic analyses suggested the highest relatedness between IMC513 and C904 strains which were both clade 4 strains, with LT52 positioned within clade 5 within the Lpb. plantarum species. The comparative genome analysis performed across several Lpb. plantarum representatives highlighted the genes involved in the key metabolic pathways as well as those encoding potential probiotic features in these new isolates. In particular, our strains varied significantly in genes encoding exopolysaccharide biosynthesis and in contrast to strains IMC513 and C904, the LT52 strain does not encode a Mannose-binding adhesion protein. The LT52 strain is also deficient in genes encoding complete pentose phosphate and the Embden–Meyerhof pathways. Finally, analyses using the CARD and ResFinder databases revealed that none of the strains encode known antibiotic resistance loci. Ultimately, the results provide better insights into the probiotic potential and safety of these three strains and indicate avenues for further mechanistic studies using these isolates.

Technological properties and probiotic potential of Lactiplantibacillus plantarum SJ14 isolated from Algerian traditional cheese “Jben”

A new Lactiplantibacillus strain isolated from Algerian traditional cheeses “Jben” was assessed for technological properties and probiotic traits in vitro including acidification, proteolytic and lipolytic activities, exopolysaccharide production, and antimicrobial potential. The strain was identified as Lactiplantibacillus plantarum SJ14 using phenotypic tests and 16S rDNA sequencing analysis. The results showed that the native food strain SJ14 was found to be tolerant to acid and bile salts mimicking human GIT conditions. In addition, the cell-free supernatant of SJ14 exhibited broad-spectrum antimicrobial activity against Gram-positive and Gram-negative bacteria including beta-lactamases-producing enteropathogenic strains as well as food spoilage fungi. The results conveyed that L. plantarum SJ14 showed desirable probiotic characteristics and its presence in cheese could serve as a potent functional probiotic starter in food processing. Novelty impact statement In Algeria, milk fermentations are still driven by indigenous microorganisms, which influence the nutritional, organoleptic, and safety of the final products. Lactic acid bacteria including Lactiplantibacillus plantarum isolated from traditional cheese “Jben” may present good candidates for further studies to elucidate the possible application as novel probiotic starter culture and biocontrol agent.

A potentially probiotic strain of Enterococcus faecalis from human milk that is avirulent, antibiotic sensitive, and nonbreaching of the gut barrier.

Human milk is a key source of promising probiotic lactic acid bacteria. The Enterococcus species, because of their dual commensal and pathogenic nature, demand critical safety analysis to establish them as probiotic candidates. In this study, eighteen E. faecalis strains from human milk of mothers living in Pakistan were typed at the strain level by riboprinting. The typed strains were then evaluated in vitro for physiological safety and the presence of transmissible antibiotic resistance genes, adhesion genes, biogenic amines, and virulence factors. Selected strains were then checked for tolerance to gastrointestinal acid and bile as criteria for probiotic efficacy. Molecular typing revealed that the strains fell into five distinct clusters or ribotypes. Testing revealed that they were non-hemolytic; however, all strains had gelatinase activity except NPL-493. The isolates were susceptible to most clinically important antibiotics except streptomycin. Molecular screening for antibiotic resistance genes, adhesion genes, biogenic amines, and virulence factors indicated that none of the strains possessed resistance genes for aminoglycosides, vancomycin, bacitracin, tetracycline, or clindamycin. Most virulence factors were absent except for the genes gelE and efaAs associated with gut adhesion and translocation, which were present in all except NPL-493. Strain NPL-493 was the most promising probiotic candidate demonstrating significant tolerance to the acid, bile, and digestive enzymes in the human GIT and antibacterial activity against multiple pathogens. The study concluded that E. faecalis NPL-493 from human milk was safe among all the strains and could be considered a potential probiotic.

A multiscale absorption and transit model for oral delivery of hydroxychloroquine: Pharmacokinetic modeling and intestinal concentration prediction to assess toxicity and drug‐induced damage in healthy subjects

Hydroxychloroquine (HCQ) is commonly used in the treatment of malaria and rheumatic diseases. Recently it has also been identified as possible therapeutic option in combating COVID-19. However, the use of HCQ is known to induce cytotoxicity. In 2020, we developed a multiscale absorption and transit (MAT) toolkit to simulate the dissolution, transport, absorption, distribution, metabolism, and elimination of orally administered drugs in the human GIT at multiple levels. MAT was constructed by integrating the spatially accurate first-principles driven high-fidelity drug transport, dissolution, and absorption model in the human stomach and GIT using the recently published Quasi-3D framework. The computational results showed that MAT was able to match the experimental concentration results better than the traditional compartmental models. In this study, we adapted MAT, to predict the pharmacokinetics of orally delivered HCQ in healthy subjects. The computational results matched the experimental concentration results. The simulated stomach and intestinal fluid and enterocyte concentrations were compared with the in vitro CC50 values. While the peak enterocyte concentrations were several orders lower than the in vitro CC50 values, the peak stomach and the intestinal fluid concentrations were only one order smaller than the in vitro CC50 values. In particular, the peak stomach and the duodenum fluid concentrations were just 3× smaller than the in vitro CC50 values. This implies that the lumen walls are much more susceptible to cytotoxicity-based damage than the enterocyte layers. We envision that MAT can be used to optimize the dosing regimen of HCQ by maximizing its bioavailability, while simultaneously minimizing the cytotoxic damage.

Proteomics fingerprints of systemic mechanisms of adaptation to bile in Lactobacillus fermentum

Lactobacillus fermentum is a natural resident of the human GIT and is used as a probiotic. A unique property of L. fermentum is its ability to tolerate, colonize, and survive in the harsh conditions of bile, which facilitates transient colonization of the host colon. In the current study, we investigated the key mechanisms of action involved in bacterial survival in the presence of bile, using high-resolution mass spectrometry. A total of 1071 proteins were identified, among which 378 were up-regulated and 368 down-regulated by ≥2-fold (t-test, p < .05). Differentially regulated proteins comprised both intracellular and surface-exposed (i.e., membrane) proteins (p < .01, t-test for total proteome analysis; p < .05, t-test for membrane proteome analysis). These alterations strengthen the cell envelope and also mediate bile efflux by adjusting carbohydrate metabolic pathways and prevention of protein misfolding. These processes are mainly involved in the active removal of bile salts or amelioration of its adverse effects on cells. Further investigation of mRNA transcript expression levels of selected proteins by quantitative reverse transcriptase-PCR verified the proteomic data. Together, our proteomics findings reveal the roles of post-stress recovery proteins and highlight the interacting pathways responsible for bacterial cell tolerance to bile stress. Biological significanceOur intestinal tract is a nutrient-rich milieu crowded with up to 100 trillion (1014) of microbes. The fact that we are born germ-free describes that these microbes must colonize our intestinal tract from outside. However, their survival is also complicated because of hazardous conditions in the gut due to the presence of bile acid and others, which exerts a deleterious effect on the beneficial microbial load. While there was limited information available describing the comprehensive mechanism of survival? Furthermore, the imbalance of these micro floras leads to numerous disease conditions. It explains the need for enhanced understanding of host-microbe interactions in the colon. The present study majorly focuses on identifying “how microbes respond to environmental stressors” in this context, particularly bile acid response. This work addresses a fascinating cellular mechanism involved in the complex changes of bile induction in the microbial system; in this case, L. fermentum NCDC 605 a well established probiotic organism. In this article, we decipher the characteristic adaptation mechanism adjusted by probiotics in the harsh condition of 1.2% bile. The generated new knowledge will also improve the potential therapeutic efficacy of probiotics strains in clinical trials for patients of inflammatory bowel diseases (IBD) and related disorders.

Safety Evaluation and Whole-Genome Annotation of Lactobacillus plantarum Strains from Different Sources with Special Focus on Isolates from Green Tea.

Lactobacillus plantarum shows high intraspecies diversity species, and has one of the largest genome sizes among the lactobacilli. It is adapted to diverse environments and provides a promising potential for various applications. The aim of the study was to investigate the safety and probiotic properties of 18 L. plantarum strains isolated from fermented food products, green tea, and insects. For preliminary safety evaluation the L. plantarum strains were tested for their ability to produce hemolysin and biogenic amines and for their antibiotic resistance. Based on preliminary safety screening, four strains isolated from green tea showed antibiotic resistance below the cut-off MIC values suggested by EFSA, and were selected out of the 18 strains for more detailed studies. Initial selection of strains with putative probiotic potential was determined by their capacity to survive in the human GIT using an in vitro simulation model, and for their adhesion to human Caco-2/TC-7 cell line. Under simulated GIT conditions, all four L. plantarum strains isolated from green tea showed higher survival rates than the control (L. plantarum subsp. plantarum ATCC 14917). All studied strains were genetically identified by 16S rRNA gene sequencing and confirmed to be L. plantarum. In addition, whole-genome sequence analysis of L. plantarum strains APsulloc 331261 and APsulloc 331263 from green tea was performed, and the outcome was compared with the genome of L. plantarum strain WCFS1. The genome was also annotated, and genes related to virulence factors were searched for. The results suggest that L. plantarum strains APsulloc 331261 and APsulloc 331263 can be considered as potential beneficial strains for human and animal applications.

Evaluation the Viability of the Saccharomyces Boulardii Bld-3 and its Influence on the Colonic Microbiota Composition by SHIME

During this study the viability of Saccharomyces Boulardii Bld-3 during passage through the upper GIT under fed and fasted conditions was evaluated. For this purpose, a Simulator of the Human Intestinal Microbial Ecosystem (SHIME®) was used, which allows to re-create the physiological conditions that are representative of the human GIT. Furthermore, the aim of this study was also to study the modulatory effect of the Saccharomyces Boulardii Bld-3 on the colonic microbiota composition and activity after passage of the strain through the fed or fasted upper GIT or when delivered directly to the colon. For this purpose, four different types of short-term colonic batch experiments were performed that simulate the colonic fermentation process.

1-hydroxy-5, 7-dimethoxy-2 naphthalene-carboxaldehyde inhibitors as novel antimycobacterial agents targeting H-InMyoFib cells and targeting enzymes involved in fatty acid biosynthesis of bacilli

Background: Gastrointestinal tuberculosis (Gastrointestinal TB) is a rapidly common infectious disease in low income countries due to poor life style that poses diagnostic challenge, as the broad spectrum features of the disease which may lead to diagnostic interruptions and complications. Early diagnosis and initiation of antituberculous therapy without drug-resistance is essential to prevent morbidity and mortality. 1-hydroxy-5, 7-dimethoxy-2 naphthalene-carboxaldehyde (HDNC) is a bioactive compound derived from Aegle marmelos (Rutaceae, ‘Bael’). It is a naturally occurring flavonoid having anticancer and wound healing properties. Methods & Materials: The present study demonstrated that HDNC had ant-mycobacterial effects on tubercle bacilli ATCC25618, multi-drug and extensively drugresistant clinical isolates with minimum inhibitory concentrations of 147 and 312 μM, respectively. Bacilli mainly affect the GIT, causing a strong local inflammatory response that is critical to the pathogenesis of tuberculosis. Results: We investigated the effects of HDNC on interferon (IFN)-γ-stimulated human GIT fibroblast H-InMyoFib cells. HDNC suppressed the release of tumor necrosis factor (TNF)-α and interleukin (IL)-12. A nontoxic dose of HDNC reduced mRNA expression of TNF-α, IL-1β, IL-6, IL-12, and matrix metalloproteinase-1 in IFN-γ-stimulated cells. HDNC inhibited IFN-γ-mediated stimulation of extracellular signal regulated kinase and p38 mitogen-activated protein kinase and showed high affinity binding to these kinases (binding constants: 3.95 × 104 M−1 and 6.8 × 103 M−1, respectively).HDNC inhibit targeting enzymes involved in fatty acid biosynthesis, such as enoyl-ACP-reductase, b-ketoacyl-ACP reductase and b-hydroxyacyl-ACP dehydratase of bacilli. A mouse in vivo study of lipopolysaccharide-induced GIT inflammation revealed that a nontoxic dose of HDNC reduced the levels of IL-1β, IL-6, IL-12, and INF-γ in GIT tissue. Conclusion: Gastrointestinal TB is generally managed with medical therapy with antituberculous drugs These data provide the first evidence that HDNC could be developed as a potent antituberculosis drug and represents as a strong candidate for the b-hydroxyacyl-ACP dehydratase enzyme of Bacilli.

Metabiotics and their Health Benefits

Probiotics are said to confer a number of health benefits on the host through their varied mechanisms of action in the human GIT. But a number of limitations exist with use of live probiotics. We are yet to be sure about the optimal dosage of probiotics, their specific mode of action, duration of the beneficial effects and the nature of the final results. The metabolic substances elaborated by probiotics and or their structural components, popularly called as metabiotics are said to provide more precise results in the above said aspects. These substances are said to possess better absorption, metabolism, distribution, and excretion abilities compared with classic probiotics based on live microorganisms. Hence use of metabiotic products may provide a more precise approach for treatment of pathological conditions associated with the imbalance of host microbiota.

Pangenome analysis of Bifidobacterium longum and site-directed mutagenesis through by-pass of restriction-modification systems.

BackgroundBifidobacterial genome analysis has provided insights as to how these gut commensals adapt to and persist in the human GIT, while also revealing genetic diversity among members of a given bifidobacterial (sub)species. Bifidobacteria are notoriously recalcitrant to genetic modification, which prevents exploration of their genomic functions, including those that convey (human) health benefits.MethodsPacBio SMRT sequencing was used to determine the whole genome seqeunces of two B. longum subsp. longum strains. The B. longum pan-genome was computed using PGAP v1.2 and the core B. longum phylogenetic tree was constructed using a maximum-likelihood based approach in PhyML v3.0. M.blmNCII was cloned in E. coli and an internal fragment if arfBarfB was cloned into pORI19 for insertion mutagenesis.ResultsIn this study we present the complete genome sequences of two Bifidobacterium longum subsp. longum strains. Comparative analysis with thirty one publicly available B. longum genomes allowed the definition of the B. longum core and dispensable genomes. This analysis also highlighted differences in particular metabolic abilities between members of the B. longum subspecies infantis, longum and suis. Furthermore, phylogenetic analysis of the B. longum core genome indicated the existence of a novel subspecies. Methylome data, coupled to the analysis of restriction-modification systems, allowed us to substantially increase the genetic accessibility of B. longum subsp. longum NCIMB 8809 to a level that was shown to permit site-directed mutagenesis.ConclusionsComparative genomic analysis of thirty three B. longum representatives revealed a closed pan-genome for this bifidobacterial species. Phylogenetic analysis of the B. longum core genome also provides evidence for a novel fifth B. longum subspecies. Finally, we improved genetic accessibility for the strain B. longum subsp. longum NCIMB 8809, which allowed the generation of a mutant of this strain.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1968-4) contains supplementary material, which is available to authorized users.

Detection of &amp;lt;i&amp;gt;Helicobacter pylori&amp;lt;/i&amp;gt; and Human Papillomavirus in Peroperative Tissue Biopsies Collected from Malignancies in Oropharyngeal Area

Helicobacter pylori has been reported as pathogen of human GIT. It is associated with type B gastritis and peptic ulcers. Bacterium´s relationship to cancer has also been declared and H. pylori considered cancer-inductor. A number of studies documented H. pylori residence in oropharynx, generating hypotheses on participation in development of cancer in oropharyngeal area. Human papillomaviruses are DNA viruses colonizing skin and mucoid membranes of the host. Their oncogenic potential, especially in genitourinary system, has been confirmed. High-risk type HPV16 (group A9) is frequently reported as cancer-inductor in oropharyngeal area. The aim of this study is to contribute to discussions on induction of malignancies in oropharyngeal area, providing comparison of incidence of one bacterial and one viral pathogen in the cells and tissues of oropharyngeal neoplasia. Using real-time PCR-based tests, we investigated 70 tissue specimens collected during cancer surgery for detection of bacterial DNA of Helicobacter pylori and viral DNA of High risk HPV (groups A9, A7 and A5/6). Results: Helicobacter pylori DNA was detected in 60 samples (85.7%), while DNA of HPV only in 42 (60%). If focused on HPV-16 as proposed cancer inductor, it was detected in 34 samples (48.5%) only. No DNA of respective agents was detected in 7 samples (10%). There were 21 Helicobacter sole pathogen detections compared with only 3 of HPV. Conclusions: There is no doubt, Helicobacter pylori is a long-term resident in oropharynx and tonsils. This residence most likely influences functions of immune system, so that a newly entering contributor could switch-on the process resulting in cancer development. This could support high incidence of common detection of HPV and Helicobacter pylori in 39 samples (55.7%).

Probiotics, prebiotics, synbiotics in prevention and treatment of inflammatory bowel diseases

Probiotics, prebiotics, and synbiotics are functional components able to exert positive effects on human health. Numerous medical conditions lack effective and safe approaches for prevention or treatment, thus usage of probiotics, prebiotics, and synbiotics is an alternative. Further, the benefit related to the consumption of these compounds is associated with lower morbidity of chronic diseases and reduced health-care costs. Various types of mediums to deliver probiotics/synbiotics to the human GIT are used. Although capsules and tablets are frequently applied as delivery systems for probiotics, the major challenge of the commercial sector is to market new functional foods containing probiotics and/or prebiotics. Discovering of new probiotic/synbiotic functional foods is connected to the interest of the food industry to revitalize continuously through introduction of products with improved nutritional value and pleasant taste, but also with health benefit for the consumers. The review provides insights and new perspectives in respect to usage of functional components and foods in prevention and treatment of inflammatory bowel diseases (IBD) that are highly correlated with the modern lifestyle. The therapeutic and safety properties of probiotics and prebiotics, their role in pathogenesis of IBD, potential to prevent and treat these diseases as well as postulated mechanisms of action will be discussed, highlighting the main areas in which further research is an emergence.

Evaluation of the role of environmental factors in the human gastrointestinal tract on the behaviour of probiotic cultures ofLactobacillus casei Shirota andLactobacillus casei LC01 by the use of a semi-dynamicin vitro model

This study evaluated the influence of gastrointestinal environmental factors (pH, digestive enzymes, food components, medicaments) on the survival ofLactobacillus casei Shirota andLactobacillus casei LC01, using a semi-dynamicin vitro model that simulates the transit of microorganisms through the human GIT. The strains were first exposed to different simulated gastric juices for different periods of time (0, 30, 60 and 120 min), and then to simulated intestinal fluids for zero, 120, 180 and 240 min, in a step-wise format. The number of viable cells was determined after each step. The influence of food residues (skim milk) in the fluids and resistance to medicaments commonly used for varied therapeutic purposes (analgesics, antiarrhythmics, antibiotics, antihistaminics, proton pump inhibitors, etc.) were also evaluated. Results indicated that survival of both cultures was pH and time dependent, and digestive enzymes had little influence. Milk components presented a protective effect, and medicamenthets, especially anti-inflammatory drugs, influenced markedly the viability of the probiotic cultures, indicating that the beneficial effects of the two probiotic cultures to health are dependent of environmental factors encountered in the human gastrointestinal tract.

Introduction to pre- and probiotics

During the last 2–3 decades, attempts for improving the human health status, are focusing on ways for modulating the indigenous intestinal flora by live microbial adjuncts, now called “probiotics”. Comprising ca. 65% of the functional food world market, probiotics represent the major and still growing segment of this huge market, estimated to exceed a total volume of US $ 75 billion. The most typical active components of probiotic products are lactic acid bacteria, including bifidobacteria, lactobacilli and enterococci. Health claims related to probiotics are numerous, but include maintenance of normal/healthy intestinal flora and protection against infections, alleviation of lactose intolerance, and stimulation of the immune system. Strains with proven beneficial effects may be consumed in relatively high numbers in products, and are collectively called probiotics. In addition. bifidobacteria and lactobacilli, typical inhabitants of the human GIT, are considered beneficial, and may be stimulated by non-digestible food ingredients such as oligosaccharides, collectively called prebiotics. Probably aimed at the two “target regions” of the GIT, pre- and probiotics may be combined in a food product, called a synbiotic. Confirmed health claims are discussed and reference will be made to open questions and research challenges.

Protection against gastrointestinal diseases—Present facts and future developments

The importance of the intestinal microflora and, more specifically its composition, in physiological and patho-physiological processes in the human GIT is becoming more evident. Examples of such processes are translocation, the production and resorption of endotoxins, immune-modulation, and colonic motility. This leads to new possibilities for prevention and therapy of diseases, mainly of the gastrointestinal organs. New discoveries are specifically related to the beneficial effects of lactobacilli which have been discussed for decades. It is possible to increase the proportion of lactobacilli in the gastrointestinal microflora by consumption of fermented dairy products or by oral administration of specific non-digestible substrates such as oligofructose. Results from clinical trials and scientific studies have confirmed the preventive and therapeutic effects of selected strains of lactobacilli in viral- and bacterial-induced intestinal infections, in positively influencing immunological parameters, in normalizing the intestinal motility, and in inhibiting metabolic events in the gut lumen which promote colonic carcinogenesis. Nevertheless, there are still unresolved issues which can only be answered by well designed and well controlled clinical trials.

Characteristic of ITS fragment of rDNA of Rhodotorula mucilaginosa isolated from gastrointestinal tract of centenarian

Aim. The aim of the work was to analyse the primary structure of the ITS region of the ribosomal operon of the red yeast isolate Rhodotorula mucilaginosa S1 from the gastrointestinal tract of healthy centenarian compared to the available homological basidimycetous nucleotide sequences. Methods. In silico comparison of the ITS nucleotide sequences using NCBI server resources (BLAST programs and "Nucleotide" database) with the reference ITS-fragment of red yeast isolate was performed. Results. Almost 90 % of highly homologous to the reference ITS-fragment out of 800 selected sequences represented genera Rhodotorula and Rhodosporidium with the top hits for R. mucilaginosa strains PMM08-1716L, 3942L and 3684L. The most frequent nucleobases mismatches of ITS-fragments of GenBank’s R. mucilaginosa strains compared to the reference one were observed in the positions 541 (T/C) for 85 % of strains, and 129 (T/C) and 158 (G/A) for 26 % of strains. Conclusions. The primary structure of studied ITS region showed 100 % homology to R. mucilaginosa strains also isolated from humans and animals, as well as the most frequently mismatches for 129th, 158th and 541st nucleotides located in the spacers regions of the ribosomal operon.&#x0D; Keywords: ITS, rDNA, nucleotide sequence, red yeast, human GIT.