Human Gastrointestinal Tract Research Articles

Immunoinformatics investigation on pathogenic Escherichia coli proteome to develop an epitope-based peptide vaccine candidate.

Escherichia coli (E. coli), a gram-negative bacterium, quickly colonizes in the human gastrointestinal tract after birth and typically sustains a long-term, symbiotic relationship with the host. However, certain virulent strains of E. coli can cause diseases such as urinary tract infections, meningitis, and enteric disorders. The rising antibiotic resistance among these strains has heightened the urgency for an effective vaccine. This study employs immunoinformatics and a reverse vaccinology technique to identify prospective antigens and create an efficient vaccine construct. In this study, we reported the "Attaching and Effacing Protein" a novel outer-membrane protein conserved in all pathogenic E. coli strains, based on proteome screening. We developed an in silico multi-epitope vaccine that includes helper T lymphocyte (HTL), cytotoxic T lymphocyte (CTL), B cell lymphocyte (BCL), and pan HLA DR-binding reactive epitope (PADRE) sequences, along with appropriate linkers and adjuvants. Machine Learning algorithms were used to evaluate antigenicity, solubility, stability, and non-allergenicity of the vaccine construct. Additionally, molecular docking analysis revealed that vaccine construct has a strong predicted binding affinity for human toll-like receptors on the cell surface. In this context, laboratory validations are necessary to demonstrate the effectiveness of the possible vaccine design that showed encouraging findings through computational validation.

Elucidating impacts of partitioning and transmembrane permeability on absorption of chemicals in human gastrointestinal tract

Estimating the fraction absorbed (Fabs) of orally ingested chemicals in the human gastrointestinal tract is pivotal for assessing chemical concentrations in the systemic circulation and informing potential toxicological impacts, especially in the era of “new approach methods” targeting chemical screening and prioritization. Here, we present an input-parsimonious and computationally efficient approach to support the screening-level estimation of Fabs from partitioning (characterized using the octanol–water partition coefficient at pH 7.4, KOW) and transmembrane permeability (characterized using the Caco-2 apparent permeability, Papp,Caco-2), based on a mechanistic description of processes involved in chemical absorption:Fabs=1-e-164571-2.40×10-9+2.40×10-9∙KOW∙10.0075∙1Papp,Caco-2-10.001530.346+10.00115Our approach demonstrates satisfactory performance in predicting Fabs for 176 hydrophobic and hydrophilic organic chemicals, with a Pearson correlation coefficient greater than 0.75 and a root mean square error of approximately 15 % in absolute Fabs values between experimental measurements and predictions. Our results show that the Fabs of highly hydrophobic chemicals (KOW > 108) are closely dependent on partitioning, whereas the Fabs of relatively hydrophilic chemicals (KOW < 106) are sensitive to transmembrane permeability. We also demonstrate that transmembrane permeability and partitioning are not interdependent, and both should be treated as fundamental chemical properties in predicting Fabs.

Prevalence and Subtypes Distribution (ST10, ST14, ST25, ST26) of Blastocystis spp. in Anatolian Water Buffalo (Bubalus bubalis) in Van, Türkiye.

Blastocystis spp. is one of the most common protozoa worldwide, living in the gastrointestinal tract of humans and many other animals. On the basis of the genetic heterogeneity of small subunit ribosomal RNA, at least 28 subtypes (ST1-ST17, ST21 and ST23-ST32) are reported to exist in mammals and birds. This study was carried out to determine the prevalence and subtypes of Blastocystis spp. in Anatolian buffaloes (Bubalus bubalis) in Van province in the Eastern Anatolia Region of Turkey. DNA was extracted using commercial GeneMATRIX Stool DNA Purification Kit and then stored at -20°C until PCR amplification. After PCR amplification of the SSU rRNA gene region positive Blastocystis spp., amplicons from buffalo faeces were sequenced and then deposited in GenBank (OR576949.1, OR576950.1, OR576970.1, OR576971.1, OR577019.1, PP837943.1, PP837940.1, PP837939.1, PP837604.1, PP837937.1, PP837934.1, PP837601.1, PP837936.1 and PP837603.1). PCR analysis of 120 faecal samples showed a total prevalence of 11.67% (14/120). The prevalence was higher in females and young animals (p>0.05). Sequence analysis revealed Blastocystis spp., ST10, ST14, ST25 and ST26 subtypes. To our knowledge, Blastocystis subtypes ST25 and ST26 in buffaloes were reported for the first time in this study. It is thought that more large-scale studies should be carried out to determine the zoonotic subtype potential of this protozoan in the region.

Functional Assessment of a Bioprinted Immuno-Mimetic Peyer's Patch Recapitulating Gut-Associated Lymphoid Tissue.

Gut immune models have attracted much interest in better understanding the microbiome in the human gastrointestinal tract. The gut-associated lymphoid tissue (GALT) has complex structures that interact with microorganisms, including the intestinal monolayer as a physiological barrier and the Peyer's patch (PP) involved in the immune system. Although essential for studying GALT and microbiome interactions, current research often uses simplified models that only recapitulate some components. In this study, GALT is recapitulated to consider the morphology and function of lymphocyte-containing PP beneath the intestinal monolayer and to analyze microbiome interaction. Using the bioprinting technique, a dome-shaped structure array for the PP is fabricated, and epithelial cells are cocultured to form the intestinal monolayer. The developed GALT model shows stable cell differentiation on the hydrogel while exhibiting durability against lipopolysaccharides. It also exhibits increased responsiveness to Escherichia coli, as indicated by elevated nitric oxide levels. In addition, the model underscores the critical role of GALT in maintaining bacterial coexistence and in facilitating immune defense against foreign antigens through the secretion of immunoglobulin A by lymphocyte spheroids. The proposed GALT model is expected to provide significant insights into studying the gut-immune system complexity and microbiome.

Microbiome dynamics: Defenses against foodborne threat

The gut microbiome is a diverse ecosystem of microorganisms inhabiting the human gastrointestinal tract, playing a crucial role in health and disease. This review examines inter-individual variability in gut microbiota composition and the impact of diet, genetics, and environmental factors on microbial diversity. It explores how probiotics and bacteriocins can serve as therapeutic agents against foodborne pathogens, offering alternatives or synergists to traditional antibiotics. The mechanisms through which probiotics interact with pathogens and the therapeutic potential of bacteriocins are analyzed. Emphasizing the need for further research, this review underscores the importance of elucidating gut microbiome interactions to improve health and disease management strategies.

Genomic Characterization of Lactiplantibacillus plantarum Strains: Potential Probiotics from Ethiopian Traditional Fermented Cottage Cheese

Background: Lactiplantibacillus plantarum is a species found in a wide range of ecological niches, including vegetables and dairy products, and it may occur naturally in the human gastrointestinal tract. The precise mechanisms underlying the beneficial properties of these microbes to their host remain obscure. Although Lactic acid bacteria are generally regarded as safe, there are rare cases of the emergence of infections and antibiotic resistance by certain probiotics. Objective: An in silico whole genome sequence analysis of putative probiotic bacteria was set up to identify strains, predict desirable functional properties, and identify potentially detrimental antibiotic resistance and virulence genes. Methods: We characterized the genomes of three L. plantarum strains (54B, 54C, and 55A) isolated from Ethiopian traditional cottage cheese. Whole-genome sequencing was performed using Illumina MiSeq sequencing. The completeness and quality of the genome of L. plantarum strains were assessed through CheckM. Results: Analyses results showed that L. plantarum 54B and 54C are closely related but different strains. The genomes studied did not harbor resistance and virulence factors. They had five classes of carbohydrate-active enzymes with several important functions. Cyclic lactone autoinducer, terpenes, Type III polyketide synthases, ribosomally synthesized and post-translationally modified peptides-like gene clusters, sactipeptides, and all genes required for riboflavin biosynthesis were identified, evidencing their promising probiotic properties. Six bacteriocin-like structures encoding genes were found in the genome of L. plantarum 55A. Conclusions: The lack of resistome and virulome and their previous functional capabilities suggest the potential applicability of these strains in food industries as bio-preservatives and in the prevention and/or treatment of infectious diseases. The results also provide insights into the probiotic potential and safety of these three strains and indicate avenues for further mechanistic studies using these isolates.

Metal availability shapes early life microbial ecology and community succession.

The gut microbiota plays a critical role in human health and disease. Microbial community assembly and succession early in life are influenced by numerous factors. In turn, assembly of this microbial community is known to influence the host, including immune system development, and has been linked to outcomes later in life. To date, the role of host-mediated nutritional immunity and metal availability in shaping microbial community assembly and succession early in life has not been explored in depth. Using a human infant cohort, we show that the metal-chelating protein calprotectin is highly abundant in infants. Taxa previously shown to be successful early colonizers of the infant gut, such as Enterococcus, Enterobacteriaceae, and Bacteroides, are highly resistant to experimental metal starvation in culture. Lactobacillus, meanwhile, is highly susceptible to metal restriction, pointing to a possible mechanism by which host-mediated metal limitation shapes the fitness of early colonizing taxa in the infant gut. We further demonstrate that formula-fed infants harbor markedly higher levels of metals in their gastrointestinal tract compared to breastfed infants. Formula-fed infants with high levels of metals harbor distinct microbial communities compared to breastfed infants, with higher levels of Enterococcus, Enterobacter, and Klebsiella, taxa which show increased resistance to the toxic effects of high metal concentrations. These data highlight a new paradigm in microbial community assembly and suggest an unappreciated role for nutritional immunity and dietary metals in shaping the earliest colonization events of the microbiota.IMPORTANCEEarly life represents a critical window for microbial colonization of the human gastrointestinal tract. Surprisingly, we still know little about the rules that govern the successful colonization of infants and the factors that shape the success of early life microbial colonizers. In this study, we report that metal availability is an important factor in the assembly and succession of the early life microbiota. We show that the host-derived metal-chelating protein, calprotectin, is highly abundant in infants and successful early life colonizers can overcome metal restriction. We further demonstrate that feeding modality (breastmilk vs formula) markedly impacts metal levels in the gut, potentially influencing microbial community succession. Our work suggests that metals, a previously unexplored aspect of early life ecology, may play a critical role in shaping the early events of microbiota assembly in infants.

Role of the SaeRS Two-Component Regulatory System in Group B Streptococcus Biofilm Formation on Human Fibrinogen.

Streptococcus agalactiae, also known as Group B Streptococcus or GBS, is a commensal colonizer of human vaginal and gastrointestinal tracts that can also be a deadly pathogen for newborns, pregnant women, and the elderly. The SaeRS two-component regulatory system (TCS) positively regulates the expression of two GBS adhesins genes, but its role in the formation of biofilm, an important step in pathogenesis, has not been investigated. In the present study, we set up a novel model of GBS biofilm formation using surfaces coated with human fibrinogen (hFg). Biofilm mass and structure were analyzed by crystal violet staining and three-dimensional fluorescence microscopy, respectively. GBS growth on hFg resulted in the formation of a mature and abundant biofilm composed of bacterial cells and an extracellular matrix containing polysaccharides, proteins, and extracellular DNA (eDNA). Enzymatic and genetic analysis showed that GBS biofilm formation on hFg is dependent on proteins and eDNA in the extracellular matrix and on the presence of covalently linked cell wall proteins on the bacterial surface but not on the type-specific capsular polysaccharide. In the absence of the SaeR regulator of the SaeRS TCS, there was a significant reduction in biomass formation, with reduced numbers of bacterial cells, reduced eDNA content, and disruption of the biofilm architecture. Overall, our data suggest that GBS binding to hFg contributes to biofilm formation and that the SaeRS TCS plays an important role in this process.

Harnessing Prebiotics to Improve Type 2 Diabetes Outcomes.

The gut microbiota, a complex ecosystem of microorganisms in the human gastrointestinal tract (GI), plays a crucial role in maintaining metabolic health and influencing disease susceptibility. Dysbiosis, or an imbalance in gut microbiota, has been linked to the development of type 2 diabetes mellitus (T2DM) through mechanisms such as reduced glucose tolerance and increased insulin resistance. A balanced gut microbiota, or eubiosis, is associated with improved glucose metabolism and insulin sensitivity, potentially reducing the risk of diabetes-related complications. Various strategies, including the use of prebiotics like inulin, fructooligosaccharides, galactooligosaccharides, resistant starch, pectic oligosaccharides, polyphenols, β-glucan, and Dendrobium officinale have been shown to improve gut microbial composition and support glycemic control in T2DM patients. These prebiotics can directly impact blood sugar levels while promoting the growth of beneficial bacteria, thus enhancing glycemic control. Studies have shown that T2DM patients often exhibit a decrease in beneficial butyrate-producing bacteria, like Roseburia and Faecalibacterium, and an increase in harmful bacteria, such as Escherichia and Prevotella. This review aims to explore the effects of different prebiotics on T2DM, their impact on gut microbiota composition, and the potential for personalized dietary interventions to optimize diabetes management and improve overall health outcomes.

The Enteric Bacterium Enterococcus faecalis Elongates and Incorporates Exogenous Short and Medium Chain Fatty Acids Into Membrane Lipids.

Enterococcus faecalis incorporates and elongates exogeneous short- and medium-chain fatty acids to chains sufficiently long to enter membrane phospholipid synthesis. The acids are activated by the E. faecalis fatty acid kinase (FakAB) system and converted to acyl-ACP species that can enter the fatty acid synthesis cycle to become elongated. Following elongation the acyl chains are incorporated into phospholipid by the PlsY and PlsC acyltranferases. This process has little effect on de novo fatty acid synthesis in the case of short-chain acids, but a greater effect with medium-chain acids. Incorporation of exogenous short-chain fatty acids in E. faecalis was greatly increased by overexpression of either AcpA, the acyl carrier protein of fatty acid synthesis, or the phosphate acyl transferase PlsX. The PlsX of Lactococcus lactis was markedly superior to the E. faecalis PlsX in incorporation of short-chain but not long-chain acids. These manipulations also allowed unsaturated fatty acids of lengths too short for direct transfer to the phospholipid synthesis pathway to be elongated and support growth of E. faecalis unsaturated fatty acid auxotrophic strains. Short- and medium-chain fatty acids can be abundant in the human gastrointestinal tract and their elongation by E. faecalis would conserve energy and carbon by relieving the requirement for total de novo synthesis of phospholipid acyl chains.

Microbial extracellular electron transfer in the human gastrointestinal tract

Microbial extracellular electron transfer in the human gastrointestinal tract Gratian Ting and Arpita Bose from Washington University in St. Louis discuss the fascinating role that extracellular electron transfer plays within the human gut. The human gut microbiome contains around hundreds of trillions of bacteria, and a great diversity of species. In fact, the number of bacteria in the human gut is similar in number to all the cells in the human body, further signifying the heterogeneity and significance of this microbiota. The habitat filtering of the human gut, defined as the non-random survival of microorganisms in relation to characteristics of the surrounding environment, is influenced by two important factors: host and diet. Disruption of normal host gut processes through various means, could cause cell death and dysbiosis, disrupting host-mediated habitat filtering. However, diet plays a far more common role in this process. Different dietary behaviors exist between individuals from cultural, moral, economic, and other means.

12468 Loss Of Enterococcus And Faecalibacterium Associate With Polycystic Ovary Syndrome And Hirsutism In A Sample Of Hispanic Patients

Abstract Disclosure: L.A. Gonzalez-Rodriguez: Research Investigator; Self; Eli Lilly &amp; Company. C.M. Casas Loyola: None. C.I. Martinez-Hernandez: None. L. El Musa Penna: None. J. Romaguera: None. F. Godoy-Vitorino: None. Polycystic Ovary Syndrome (PCOS) is a common endocrine disorder affecting women of reproductive age. It is characterized by symptoms such as irregular menstrual periods, excess androgen levels and polycystic ovaries. Women with PCOS often display insulin resistance independent of fat and have been associated with an increased risk of diabetes mellitus, cardiovascular disease, and mood disorders. The gut microbiota, the community of microbes living in the human gastrointestinal tract, plays a crucial role in human health and has been implicated in various diseases, including metabolic and inflammatory conditions. We aimed to characterize the gut microbiota in a sample of Hispanic women living in Puerto Rico (n=50). Of these 38 had confirmed PCOS as per Rotterdam criteria and 12 were controls. A stool sample was collected for genomic DNA extractions followed by amplification and sequencing of 16S rRNA genes (V4 region) with Illumina MiSEQ. Data analyses were performed with standard pipelines with variables sample group (PCOS vs Controls), insulin resistance assessed using HOMA-IR and hirsutism status according to modified-Ferriman Gallwey (mFG) score and controlled for age and other clinical variables. Despite there were no changes in alpha or beta diversity among the microbiota of these groups, composition was significantly different. Women with PCOS had significantly lower levels of Enterococcus species as well as Hungatella, taxa that are part of a physiologically normal gut flora. Enterococcus species contribute to the balance of the microbial community and play roles in the metabolism and immune function and are very resilient. Hungatella species are a known source of catabolic enzymes that degrade glycosaminoglycans which are important in tissue repair. These dominant taxa in controls was substituted by other taxa in PCOS. Women with prominent hirsutism had significantly lower levels of Faecalibacterium while those with insulin resistance had increased levels of Clostridium. We found that higher levels Clostridium, and lower levels of protective anti-inflammatory taxa such as Faecalibacterium or Enterococci, which are important for gut health and metabolic regulation, are linked to this metabolic disturbance. Even though this is a preliminary report, it opens potential therapeutic strategies, such as the use probiotics, and dietary modifications to modulate the gut microbiome and improve PCOS outcomes. Presentation: 6/1/2024

12468 Loss Of Enterococcus And Faecalibacterium Associate With Polycystic Ovary Syndrome And Hirsutism In A Sample Of Hispanic Patients

Abstract Disclosure: L.A. Gonzalez-Rodriguez: Research Investigator; Self; Eli Lilly &amp; Company. C.M. Casas Loyola: None. C.I. Martinez-Hernandez: None. L. El Musa Penna: None. J. Romaguera: None. F. Godoy-Vitorino: None. Polycystic Ovary Syndrome (PCOS) is a common endocrine disorder affecting women of reproductive age. It is characterized by symptoms such as irregular menstrual periods, excess androgen levels and polycystic ovaries. Women with PCOS often display insulin resistance independent of fat and have been associated with an increased risk of diabetes mellitus, cardiovascular disease, and mood disorders. The gut microbiota, the community of microbes living in the human gastrointestinal tract, plays a crucial role in human health and has been implicated in various diseases, including metabolic and inflammatory conditions. We aimed to characterize the gut microbiota in a sample of Hispanic women living in Puerto Rico (n=50). Of these 38 had confirmed PCOS as per Rotterdam criteria and 12 were controls. A stool sample was collected for genomic DNA extractions followed by amplification and sequencing of 16S rRNA genes (V4 region) with Illumina MiSEQ. Data analyses were performed with standard pipelines with variables sample group (PCOS vs Controls), insulin resistance assessed using HOMA-IR and hirsutism status according to modified-Ferriman Gallwey (mFG) score and controlled for age and other clinical variables. Despite there were no changes in alpha or beta diversity among the microbiota of these groups, composition was significantly different. Women with PCOS had significantly lower levels of Enterococcus species as well as Hungatella, taxa that are part of a physiologically normal gut flora. Enterococcus species contribute to the balance of the microbial community and play roles in the metabolism and immune function and are very resilient. Hungatella species are a known source of catabolic enzymes that degrade glycosaminoglycans which are important in tissue repair. These dominant taxa in controls was substituted by other taxa in PCOS. Women with prominent hirsutism had significantly lower levels of Faecalibacterium while those with insulin resistance had increased levels of Clostridium. We found that higher levels Clostridium, and lower levels of protective anti-inflammatory taxa such as Faecalibacterium or Enterococci, which are important for gut health and metabolic regulation, are linked to this metabolic disturbance. Even though this is a preliminary report, it opens potential therapeutic strategies, such as the use probiotics, and dietary modifications to modulate the gut microbiome and improve PCOS outcomes. Presentation: 6/1/2024

PBPK modeling: What is the role of CYP3A4 expression in the gastrointestinal tract to accurately predict first-pass metabolism?

Gastrointestinal first-pass metabolism plays an important role in bioavailability and in drug-drug interactions. Physiologically-based pharmacokinetic (PBPK) modeling is a powerful tool to integrate these processes mechanistically. However, a correct bottom-up prediction of GI first-pass metabolism is challenging and depends on various model parameters like the level of enzyme expression and the basolateral intestinal mucosa permeability (Pmucosa). This work aimed to investigate if cytochrome P450 (CYP) 3A4 expression could help predict the first-pass effect using PBPK modeling or whether additional factors like Pmucosa do play additional roles using PBPK modeling. To this end, a systematic review of the absolute CYP3A expression in the human gastrointestinal tract and liver was conducted. The resulting CYP3A4 expression profile and two previously published profiles were applied to PBPK models of seven CYP3A4 substrates (alfentanil, alprazolam, felodipine, midazolam, sildenafil, triazolam, and verapamil) built-in PK-Sim®. For each compound, it was assessed whether first-pass metabolism could be adequately predicted based on the integrated CYP3A4 expression profile alone or whether an optimization of Pmucosa was required. Evaluation criteria were the precision of the predicted interstudy bioavailabilities and area under the concentration-time curves. It was found that none of the expression profiles provided upfront an adequate description of the extent of GI metabolism and that optimization of Pmucosa as a compound-specific parameter improved the prediction of most models. Our findings indicate that a pure bottom-up prediction of gastrointestinal first-pass metabolism is currently not possible and that compound-specific features like Pmucosa must be considered as well.

Molecular Characterization of Carbapenemase (Blakpc-2) Gene From Klebsiella Pneumoniae Involved in Urinary Tract Infection in Al-Najaf City

Background: The human gastrointestinal tract, eyes, respiratory system, and genitourinary tract are all home to K. pneumonia. KPCs, or Klebsiella pneumonia carbapenemases, are β-lactamase enzyme types that have the ability to hydrolyze β-lactam drugs. Because of many co-morbid diseases, immunological suppression, and critical sickness, this KPC-producing strain infection can be fatal. In this study K. pneumonia was isolated from urinary tract infected patients, Where seven clinical urine specimen obtained from patients has UTI were gathered from different diagnostic Al-Sajjad Hospital in Najaf province the KPC gene was amplified by PCR. In this present study, a particular primer derived from the antibiotic sensitivity (blaKPC-2) gene is used to screen the urine samples collected for Klebsiella pneumoniae stains utilizing culture techniques then sequence analysis of the blaKPC-2 gene was conducted in order to gain a fresh understanding of the genetic variations. It's interesting to note that, while comparing our strains' blaKPC-2 open reading frame to previously released sequences, we discovered 6 mutations. Therefore, of the seven samples analyzed, three exhibited a positive band. The purpose of the primer was to amplify the bacteria's blaKPC-2 antibiotic sensitivity gene. Conclusion: In this work, we verified a PCR technique for blaKPC-2 gene identification that is quick, sensitive, and specific. Out of the seven samples analyzed, three exhibited a positive band. The purpose of the primer was to amplify the bacteria's blaKPC-2 antibiotic sensitivity gene.

Bivalent norovirus mRNA vaccine elicits cellular and humoral responses protecting human enteroids from GII.4 infection

Nucleoside-modified mRNA-LNP vaccines have revolutionized vaccine development against infectious pathogens due to their ability to elicit potent humoral and cellular immune responses. In this article, we present the results of the first norovirus vaccine candidate employing mRNA-LNP platform technology. The mRNA-LNP bivalent vaccine encoding the major capsid protein VP1 from GI.1 and GII.4 of human norovirus, generated high levels of neutralizing antibodies, robust cellular responses, and effectively protected human enteroids from infection by the most prevalent genotype (GII.4). These results serve as a proof of concept, demonstrating that a modified-nucleoside mRNA-LNP vaccine based on norovirus VP1 sequences can stimulate an immunogenic response in vivo and generates neutralizing antibodies capable of preventing viral infection in models of human gastrointestinal tract infection.

Candida albicans strains adapted to the mouse gut are resistant to bile salts via a Flo8-dependent mechanism

Candidaalbicans normally colonizes the human gastrointestinal tract as a commensal. Studying fungal factors involved in colonizing the mammalian gastrointestinal tract requires mouse models with altered microbiota. We have obtained strains of C.albicans through microevolution in the mouse gut for a prolonged period (one year) that display a substantial increase in fitness in this niche. These strains show resistance to bile salts, an increase in their adhesion to the intestinal mucosa, and are unable to filament in response to serum. Genetic analysis revealed some alterations, mainly a triploidy of chr7, a whole chr6 homozygosis, and an SNP in the FLO8 gene (located in the chr6), resulting in a truncated protein version. A wild type FLO8 gene complemented filamentation and bile salt sensitivity, but showed an intermediate fitness phenotype in colonization. Alterations in bile salt sensitivity were also evident in bmt mutants, defective in β-mannosylation, and transcriptional targets of Flo8, suggesting a link between the fungal cell wall and mammalian gut colonization via the Flo8 transcriptional regulator.

The importance of bacteria of the genus Bifidobacterium in intestinal microbiocenosis

Bifidobacteria are the most common microorganisms in the intestines of healthy breastfed children. The genus Bifidobacterium includes bacteria characterized by probiotic properties, such as the induction of immunomodulators, increasing the nutritional value of products due to the assimilation of substrates that are not broken down by the host, anticarcinogenic activity, synthesis of vitamins, production of antimicrobial drugs, which contribute to the promotion of health. Bifidobacteria demonstrate physiological and genetic characteristics including adhesion to the intestinal epithelium, as well as metabolism of glycans in the host body. Multitrophic interaction is formed based on various mechanisms of substrate recognition in the surrounding environment and the transmission of molecular and genetic information, which contributes to survival in the human gastrointestinal tract. Representatives of the Bifidobacterium bifidum species constitute a dominant taxon among bifidobacteria, demonstrating significant probiotic properties and extensive potential for the treatment and prevention of various diseases. Currently, a large number of Bifidobacterium bifidum species have been sequenced, which are of interest to medicine, biotechnology, and agriculture. Their genetic strategies for colonizing and persisting in the human intestine have been identified. Cross-interaction mechanisms of Bifidobacterium bifidum with the host and other microorganisms have been demonstrated using various structures. In this review, we discuss current knowledge about the biology of the genus Bifidobacterium, including the biological characteristics of Bifidobacterium bifidum species, which exhibit specific adaptations to the human intestine.

Micronization of wholewheat flour increases iron bioavailability from hydrothermally processed wheat flour dough

Cereal products contribute significantly to dietary intake of essential minerals. In wheat, iron and zinc are stored in specific grain structures including the aleurone, scutellum and embryo. Wheat cell walls are resistant to digestion in the human gastrointestinal tract and therefore this study investigated the hypothesis that physical disruption of the cell walls would increase the bioaccessibility and bioavailability of iron and zinc from wheat-based foods. Flour was micronized using a combination of roller milling and a micro-mill and this reduced median particle size by two-thirds. Hydrothermally processed wheat flour doughs were subjected to in vitro digestion to determine mineral bioaccessibility. Mineral bioavailability from food digests was measured using human intestinal Caco-2 cells. Iron (but not zinc) bioavailability from wheat foods made using the micronized flour (2.5 ± 0.5 nmol/mg cell protein) was increased significantly compared with foods produced from standard milled flour (1.3 ± 0.1 nmol/mg cell protein; P = 0.031). Micronization of wheat flour has the potential to increase the absorption of the endogenous iron present in cereal foods and this might have health benefits for population groups with poor iron status.

Enhancing Food Sustainability through Probiotics Isolated from Fermented Cauliflower

In the face of increasing challenges to sustainable food production, biotechnology offers solutions to support the environmental and health aspects of the food industry. This study explores the probiotic potential of L. plantarum and L. brevis isolated from fermented cauliflower. The probiotic properties of the strains and their biochemical characteristics were comprehensively assessed. They have been shown to be resistant to conditions in the human gastrointestinal tract and are able to adhere to colonic epithelial cells. Beneficial properties, such as antimicrobial activity and the production of phenolic acid and exopolysaccharides, were confirmed. The safety of these isolates was established, highlighting their suitability as pro- and prebiotics, and as fermentation starters. In particular, C5 and C2 strains have shown promising industrial potential, with C5 excelling in overall performance and C2 exhibiting strong antagonism to pathogenic strains and superior adhesion to intestinal cells. The resilience of strain C5 under various stress conditions and the exceptional exopolysaccharide production by strain C2 further underscore their unique capabilities and potential applications. These distinct properties make them particularly suitable for applications in functional foods and health-oriented products. These results emphasize the importance of fermented foods in promoting sustainable agricultural practices and consumer health, contributing to a more sustainable food industry.