Potential antimicrobial activity of camel milk as a traditional functional food against foodborne pathogens in vivo and in vitro.

Foodborne pathogens are a leading cause of mortality worldwide. Therefore, strategies focused on functional foods are urgently required to tackle this issue. As a result, camel milk is one of the most important traditional functional foods since it contains a variety of bioactive components, which all have antimicrobial activity against foodborne pathogens. The study aims to investigate the potential antimicrobial activity of raw camel milk against foodborne pathogens in both in vitro agar well diffusion and infected mice, especially Listeria monocytogenes, Staphylococcus aureus, Salmonella Typhimurium and Escherichia coli, particularly in societies that rely on consuming camel milk in its raw form. A total of eighty C57BL/6 mice were divided into ten groups and gavaged with or without camel milk for two consecutive weeks. A blood plasma analysis and serum insulin levels were measured. Histological investigations of the liver, pancreas, kidney, spleen, lung and testicles were also performed. In both in vivo and in vitro studies when compared to other pathogenic bacteria, E. coli was the most affected by raw camel milk, with a significant clear zone of 2.9 ± 0.13 cm in vitro and in all measured parameters in vivo (p < 0.05). As a result, we advocated for further research to improve camel breeding, raise milk yield and extend its reproductive capability as one of the most important farm animals.

Structural Characterization and Immunomodulatory Activity of a Mannose-Rich Polysaccharide Isolated from Bifidobacterium breve H4-2.

In this study, a novel homogeneous mannose-rich polysaccharide named EPS-1 from the fermentation broth of Bifidobacterium breve H4-2 was isolated and purified by anion exchange column chromatography and gel column chromatography. The primary structure of EPS-1 was analyzed by high-performance liquid chromatography, Fourier-transform infrared spectroscopy, gas chromatography-mass spectrometry, and nuclear magnetic resonance. The results indicated that EPS-1 had typical functional groups of polysaccharides. EPS-1 with an average molecular weight of 3.99 × 104 Da was mainly composed of mannose (89.65%) and glucose (5.84%). The backbone of EPS-1 was →2,6)-α-d-Manp-(1→2)-α-d-Manp-(1→2,6)-α-d-Manp-(1→2)-α-d-Manp-(1→2,6)-α-d-Manp-(1→6)-α-d-Glcp-(1→ simultaneously containing two kinds of branched chains (α-d-Manp-(1→3)-α-d-Manp-(1→ and α-d-Manp-(1→). Besides, EPS-1 had a triple-helical conformation and exhibited excellent thermal stability. Moreover, the immunomodulatory activity of EPS-1 was evaluated by RAW 264.7 cells. Results indicated that EPS-1 significantly enhanced the viability of RAW 264.7 cells. EPS-1 could also be recognized by toll-like receptor 4, thereby activating the nuclear factors-κB (NF-κB) signaling pathway, promoting phosphorylation of related nuclear transcription factors, improving cell phagocytic activity, and promoting the secretion of NO, IL-6, IL-1ß, and TNF-α. Thus, EPS-1 could activate the TLR4-NF-κB signaling pathway to emerge immunomodulatory activity on macrophages. The above results indicate that EPS-1 can serve as a potential immune-stimulating polysaccharide.

Bifidobacterium breve Alleviates DSS-Induced Colitis in Mice by Maintaining the Mucosal and Epithelial Barriers and Modulating Gut Microbes.

This study was designed to explore the different intestinal barrier repair mechanisms of Bifidobacterium breve (B. breve) H4-2 and H9-3 with different exopolysaccharide (EPS) production in mice with colitis. The lipopolysaccharide (LPS)-induced IEC-6 cell inflammation model and dextran sulphate sodium (DSS)-induced mice colitis model were used. Histopathological changes, epithelial barrier integrity, short-chain fatty acid (SCFA) content, cytokine levels, NF-κB expression level, and intestinal flora were analyzed to evaluate the role of B. breve in alleviating colitis. Cell experiments indicated that both B. breve strains could regulate cytokine levels. In vivo experiments confirmed that oral administration of B. breve H4-2 and B. breve H9-3 significantly increased the expression of mucin, occludin, claudin-1, ZO-1, decreased the levels of IL-6, TNF-α, IL-1ß and increased IL-10. Both strains of B. breve also inhibited the expression of the NF-κB signaling pathway. Moreover, B. breve H4-2 and H9-3 intervention significantly increased the levels of SCFAs, reduced the abundance of Proteobacteria and Bacteroidea, and increased the abundance of Muribaculaceae. These results demonstrate that EPS-producing B. breve strains H4-2 and H9-3 can regulate the physical, immune, and microbial barrier to repair the intestinal damage caused by DSS in mice. Of the two strains, H4-2 had a higher EPS output and was more effective at repair than H9-3. These results will provide insights useful for clinical applications and the development of probiotic products for the treatment of colitis.

Postbiotic Gamma-Aminobutyric Acid and Camel Milk Intervention as Innovative Trends Against Hyperglycemia and Hyperlipidemia in Streptozotocin-Induced C57BL/6J Diabetic Mice.

Diabetes is a serious disease that threatens human health worldwide. The study hypothesis is to investigate the novel trends that may aid in the prevention of diabetic complications. Camel milk was presented as traditional functional food, and Lactobacillus brevis KLDS1.0727 and KLDS1.0373 strains were shown to synthesize postbiotic Gamma-aminobutyric acid as a potential food additive, which can therapeutically intervene against hyperglycemia and hyperlipidemia in streptozotocin-induced C57BL/6J mice. During a four-week timeframe, body weight and postprandial blood glucose levels were monitored. Post-euthanasia, blood plasma was obtained to investigate hyperlipidemia, insulin concentrations, liver, and renal functions. The liver, pancreas, kidney, and spleen underwent histopathological examinations. The results demonstrated that KLDS1.0727 and KLDS1.0373 (LACS1 , LACS2 ) and camel milk treatments all had a significant influence on hypoglycemic activity, as evidenced by reduced postprandial blood glucose levels. LACS1 , LACS2 , and camel milk therapy significantly reduced blood hypolipidemic, and some liver enzymes such as (alanine aminotransferase and aspartate transaminase) levels. Therefore, we recommend consuming camel milk regularly and expanding its use with fermented foods containing L. brevis, one of the probiotics capable of producing gamma-aminobutyric acid (GABA) as future food additives that can improve human health and reduce the prevalence of several diseases disorders.

Relationship between clinical features and intestinal microbiota in Chinese patients with ulcerative colitis.

BACKGROUND: Dysbacteriosis may be a crucial environmental factor for ulcerative colitis (UC). Further study is required on microbiota alterations in the gastrointestinal tract of patients with UC for better clinical management and treatment. AIM: To analyze the relationship between different clinical features and the intestinal microbiota, including bacteria and fungi, in Chinese patients with UC. METHODS: Eligible inpatients were enrolled from January 1, 2018 to June 30, 2019, and stool and mucosa samples were collected. UC was diagnosed by endoscopy, pathology, Mayo Score, and Montreal classification. Gene amplicon sequencing of 16S rRNA gene and fungal internal transcribed spacer gene was used to detect the intestinal microbiota composition. Alpha diversity, principal component analysis, similarity analysis, and Metastats analysis were employed to evaluate differences among groups. RESULTS: A total of 89 patients with UC and 33 non-inflammatory bowel disease (IBD) controls were enrolled. For bacterial analysis, 72 stool and 48 mucosa samples were obtained from patients with UC and 21 stool and 12 mucosa samples were obtained from the controls. For fungal analysis, stool samples were obtained from 43 patients with UC and 15 controls. A significant difference existed between the fecal and mucosal bacteria of patients with UC. The α-diversity of intestinal bacteria and the relative abundance of some families, such as Lachnospiraceae and Ruminococcaceae, decreased with the increasing severity of bowel inflammation, while Escherichia-Shigella showed the opposite trend. More intermicrobial correlations in UC in remission than in active patients were observed. The bacteria-fungi correlations became single and uneven in patients with UC. CONCLUSION: The intestinal bacteria flora of patients with UC differs significantly in terms of various sample types and disease activities. The intermicrobial correlations change in patients with UC compared with non-IBD controls.

Beneficial effects of lactitol on the composition of gut microbiota in constipated patients.

OBJECTIVE: To explore the changes in microbial composition and the corresponding impact after lactitol treatment in constipated patients. METHODS: Altogether 29 consecutive outpatients diagnosed with chronic constipation from three centers were recruited and stratified based on their history of diabetes mellitus. All patients were administered with oral lactitol for 2 weeks, and a symptoms diary of constipation was recorded. Fecal samples were collected before and after lactitol treatment, and were analyzed by 16S rRNA sequencing and real-time polymerase chain reaction (PCR) to detect gut microbiota. RESULTS: Twenty patients with diabetes mellitus and nine without, all with chronic constipation, were enrolled in this study. After 2-week administration of lactitol, their subscale scores and constipation symptoms significantly decreased (P < 0.05). An analysis of fecal flora using 16S rRNA sequencing found an increasing trend of abundance of Bifidobacterium in the post-lactitol group (P = 0.08). Actinobacteria, Actinobacteria, Bifidobacteriales, Bifidobacteriaceae and Bifidobacterium were significantly more abundant after lactitol administration. Real-time PCR showed significantly high DNA copy numbers of Bifidobacterium after lactitol treatment (1.39 × 1010 vs 2.74 × 109 copies/µL, P = 0.01). The results of 16S rRNA sequencing and real-time PCR illustrated an increasing trend of Bifidobacterium in both patients with and without diabetes. In addition, Bifidobacterium was negatively correlated with constipation subscale scores. CONCLUSIONS: Alterations in fecal flora composition after lactitol supplementation, especially in terms of an increasing trend of Bifidobacterium, alleviated constipation symptoms. Lactitol may be a promising prebiotic candidate for patients with constipation, regardless of diabetes mellitus.

Effects of probiotics and prebiotics on intestinal microbiota in mice with acute colitis based on 16S rRNA gene sequencing.

BACKGROUND: Imbalance of intestinal microbiota was closely related to colitis. Under these circumstances, regulation of enteric flora may be beneficial to the repair of inflammation. We aimed to investigate the effects of probiotics (Bifidobacterium and Lactobacillus), prebiotics and their combination on inflammation, and microflora in mice of acute colitis. METHODS: C57BL/6J mice were divided into six groups randomly (blank control group, model control group, probiotics group, synbiotics group, lactitol group and probiotics + lactitol group). Each group was given 2.5% dextran sulfate sodium drinking water for 5 days other than the blank control group. Except for the model control group, the other four groups were intervened with probiotics, synbiotics (probiotics and inulin), lactitol, and probiotics + lactitol. Mice were sacrificed after 1 week of gavage, and pathologic scores were calculated. The feces of different periods and intestinal mucosa samples were collected to analyze the differences of intestinal microbiota by 16S rRNA sequencing. Differences of two groups or multiple groups were statistically examined through unpaired Student t test and analysis of variance (ANOVA), respectively. ANOVA, Tukey, Anosim, and metastats analysis were used to compare differences of microbiota among different groups. RESULTS: After gavage for 1 week, the pathologic scores of groups with the intervention were significantly lower than those in the model control group, and the difference was statistically significant (P < 0.05). The model control group was higher in the genus of Bacteroides (relative abundance: 0.3679 vs. 0.0099, P = 0.0016) and lower in Lactobacillus (relative abundance: 0.0020 vs. 0.0122, P = 0.0188), Roseburia (relative abundance: 0.0004 vs. 0.0109, P = 0.0157), compared with the blank control group. However, the same phenomenon was not found in groups gavaged with probiotics and lactitol. Compared with model control group, mice with intervention were increased with Bifidobacterium (relative abundance: 0.0172 vs. 0.0039, P = 0.0139), Lachnospiraceae_NK4A136_group (relative abundance: 0.1139 vs. 0.0320, P = 0.0344), Lachnospiraceae_UCG-006 (relative abundance: 0.0432 vs. 0.0054, P = 0.0454), and decreased with Alistipes (relative abundance: 0.0036 vs. 0.0105, P = 0.0207) in varying degrees. The mucosal flora was more abundant than the fecal flora, and genus of Mucispirillum (relative abundance: 0.0207 vs. 0.0001, P = 0.0034) was more common in the mucosa. Lactitol group showed higher level of Akkermansia than model control group (relative abundance: 0.0138 vs. 0.0055, P = 0.0415), probiotics group (relative abundance: 0.0138 vs. 0.0022, P = 0.0041), and synbiotics group (relative abundance: 0.0138 vs. 0.0011, P = 0.0034), while probiotics + lactitol group had more abundant Akkermansia than synbiotics group (relative abundance: 0.0215 vs. 0.0013, P = 0.0315). CONCLUSIONS: Probiotics and prebiotics reduce the degree of inflammation in acute colitis mice obviously. Mice with acute colitis show reduced beneficial genera and increased harmful genera. Supplementation of probiotics and prebiotics display the advantage of increasing the proportion of helpful bacteria and regulating the balance of intestinal microbiota. Lactitol might promote the proliferation of Akkermansia.

Screening Potential Probiotic Characteristics of Lactobacillus brevis Strains In Vitro and Intervention Effect on Type I Diabetes In Vivo.

Diabetes has become the third most serious threat to human health, after cancer and cardiovascular disease. Notably, Lactobacillus brevis is the most common species of LAB that produces γ-aminobutyric acid (GABA). The aim of this study is to clarify the effect of time, strain types, antibiotic concentrations, different levels of pH, and intestinal juices in aerobic or anaerobic conditions and the effect of interactions between these factors on the potential properties of KLDS 1.0727 and KLDS 1.0373, furthermore, antagonistic activity against foodborne pathogens. Moreover, another aim is to study the capability of KLDS 1.0727 and KLDS 1.0373 strains as gad gene carriers to express GABA that reduce the risk of type 1 diabetes in C57BL/6 mice as diabetic models. The obtained results exhibited the surprising tolerance of Lactobacillus brevis strains in vitro digestion models mimicking the conditions of the gastrointestinal tract, further, large antagonistic activity against foodborne pathogeneses. In vivo results displayed the significant effect on glucose level reduction, blood plasma, and histological assays of mice organs. As recommended, the use of Lactobacillus brevis strains should be widely shared in the market as a natural source of GABA in pharmaceutical and food applications.

[Clinical Features of Pneumocystis Jiroveci Pneumonia in Patients with Inflammatory Bowel Disease].

Objective To investigate the clinical features of patients with inflammatory bowel disease (IBD) complicated with Pneumocystis Jiroveci Pneumonia (PJP). Methods We retrospectively analyzed the clinical data of 5 patients who were hospitalized in Peking Union Medical College Hospital from January 2012 to July 2017 for treatment of IBD complicated with PJP. Demographic characteristics,clinical manifestations,treatments,and outcomes were descriptively analyzed. Results Of these five patients,four had ulcerative colitis (UC) and one had Crohn's disease (CD). All patients were males,with an average age of (61.8±1.9) years. All patients were in active disease status and had symptoms including cough and suffocation. Three patients had hypoxemia,among whom two developed type 1 respiratory failure. Three patients were treated with immunosuppressive medications (corticosteroids and/or immunosuppressant drugs) before the diagnosis of PJP. Lymphocyte counts in three patients were less than 0.6×109/L. CD4+T cells in two patients were less than 200×106/L. Four patients had elevated serum cytomegalovirus DNA. The level of ß-D-glucan was elevated in four patients. Chest CT showed bilateral diffuse ground glass opacification. PJP-DNA was positive in sputum or bronchoalveolar lavage fluid in all patients. Two patients with type 1 respiratory failure required invasive mechanical ventilation. All patients received trimethoprim-sulfamethoxazole and methylprednisolone treatment. Four patients recovered completely and one died. Conclusion Elderly (aged>55 years) IBD patients who are receiving immune-suppressive therapy or with decreased peripheral blood lymphocyte count are at higher risk of PJP.

Effect of Lactobacillus acidophilus KLDS 1.0738 on miRNA expression in in vitro and in vivo models of ß-lactoglobulin allergy.

This study aims to investigate the correlation between the ability of L. acidophilus to modulate miRNA expression and prevent Th17-dominated ß-lactoglobulin (ß-Lg) allergy. In vitro immunomodulation was evaluated by measuring splenocyte proliferation, Th17-related immune response and miRNA expression in ß-Lg-sensitized splenocytes cultured with live L. acidophilus. Next, the allergic mouse model was used to evaluate anti-allergy capability of lactobacilli. The ß-Lg challenge led to induction of up-regulation of miR-146a, miR-155, miR-21 and miR-9 expression in both in vivo and in vitro, along with increased Th17-related cytokine levels and mRNA expression of RORγt and IL-17. However, treatment of live L. acidophilus significantly suppressed hypersensitivity responses and Th17 cell differentiation. Moreover, administration of live L. acidophilus reduced expression of four miRNAs, especially miR-146a and miR-155. In addition, the decreased expression of the miRNAs in the spleen of the L. acidophilus-treated group was closely associated with decrease of IL-17 and RORγt mRNA expression.

Role of luxS in Stress Tolerance and Adhesion Ability in Lactobacillus plantarum KLDS1.0391.

Lactobacillus plantarum, a probiotic, has a high survival rate and high colonization ability in the gastrointestinal tract. Tolerance to the gastrointestinal environment and adhesion to intestinal epithelial cells by some Lactobacillus species (excluding L. plantarum) are related to luxS/AI-2. Here, the role of luxS in tolerance to simulated digestive juice (SDJ) and adhesion to Caco-2 cells by L. plantarum KLDS1.0391 (hereafter, KLDS1.0391) was investigated. The KLDS1.0391 luxS mutant strain was constructed by homologous recombination. When luxS was deleted, acid and bile salt tolerance and survival rates in SDJ significantly decreased (p < 0.05 for all). The ability of the luxS deletion strain to adhere to Caco-2 cells was markedly lower than that of the wild-type strain (p < 0.05). The ability of the luxS mutant strain to adhere (competition, exclusion, and displacement) to Escherichia coli ATCC 25922 was significantly lower than that of the wild-type strain (p < 0.05 for all). A significant decrease was noted only in the exclusion adhesion inhibition of the luxS mutant strain to Salmonella typhimurium ATCC 14028 (p < 0.05). These results indicate that the luxS gene plays an important role in the gastrointestinal environment tolerance and adhesion ability of KLDS1.0391.

Role of the luxS gene in bacteriocin biosynthesis by Lactobacillus plantarum KLDS1.0391: A proteomic analysis.

Certain probiotic species of lactic acid bacteria, especially Lactobacillus plantarum, regulate bacteriocin synthesis through quorum sensing (QS) systems. In this study, we aimed to investigate the luxS-mediated molecular mechanisms of QS during bacteriocin synthesis by L. plantarum KLDS1.0391. In the absence of luxS, the 'spot-on-the-lawn' method showed that the bacteriocin production by L. plantarum KLDS1.0391 significantly decreased upon co-cultivation with L. helveticus KLDS1.9207 (P < 0.01) but did not change significantly when mono-cultivated. Furthermore, liquid chromatography-electrospray ionization tandem mass spectrometry analysis showed that, as a response to luxS deletion, L. plantarum KLDS1.0391 altered the expression level of proteins involved in carbohydrate metabolism, amino acid metabolism, fatty acid synthesis and metabolism, and the two-component regulatory system. In particular, the sensor histidine kinase AgrC (from the two-component system, LytTR family) was expressed differently between the luxS mutant and the wild-type strain during co-cultivation, whereas no significant differences in proteins related to bacteriocin biosynthesis were found upon mono-cultivation. In summary, we found that the production of bacteriocin was regulated by carbohydrate metabolism, amino acid metabolism, fatty acid synthesis and metabolism, and the two-component regulatory system. Furthermore, our results demonstrate the role of luxS-mediated molecular mechanisms in bacteriocin production.

Production of a Functional Frozen Yogurt Fortified with Bifidobacterium spp.

Frozen dairy products have characteristics of both yogurt and ice cream and could be the persuasive carriers of probiotics. Functions of the frozen yogurt containing viable bifidobacterial cells are recognized and favored by the people of all ages. We developed a kind of yogurt supplemented by Bifidobacterium species. Firstly, five strains of Bifidobacterium spp. (Bifidobacterium bifidum ATCC 11547, Bifidobacterium longum ATCC 11549, Bifidobacterium infantis ATCC 11551, Bifidobacterium adolescentis ATCC 11550, and Bifidobacterium breve ATCC 11548) were evaluated based on the feasibility criteria of probiotics, comprising acid production, bile tolerance, and adhesion to epithelial cells. Formerly, we combined the optimum strains with yogurt culture (Lactobacillus delbrueckii subsp. bulgaricus EMCC 11102 and Streptococcus salivarius subsp. thermophilus EMCC 11044) for producing frozen yogurt. Finally, physiochemical properties and sensory evaluation of the frozen yogurt were investigated during storage of 60 days at -18°C. Results directed that Bifidobacterium adolescentis ATCC 11550 and Bifidobacterium infantis ATCC 11551 could be utilized with yogurt culture for producing frozen yogurt. Moreover, the frozen yogurt fermented by two bifidobacterial strains and yogurt culture gained the high evaluation in the physiochemical properties and sensory evaluation. In summary, our results revealed that there was no significant difference between frozen yogurt fermented by Bifidobacterium spp. and yogurt culture and that fermented by yogurt culture only.

Complete genome sequence of bacteriocin-producing Lactobacillus plantarum KLDS1.0391, a probiotic strain with gastrointestinal tract resistance and adhesion to the intestinal epithelial cells.

Lactobacillus plantarum KLDS1.0391 is a probiotic strain isolated from the traditional fermented dairy products and identified to produce bacteriocin against Gram-positive and Gram-negative bacteria. Previous studies showed that the strain has a high resistance to gastrointestinal stress and has a high adhesion ability to the intestinal epithelial cells (Caco-2). We reported the entire genome sequence of this strain, which contains a circular 2,886,607-bp chromosome and three circular plasmids. Genes, which are related to the biosynthesis of bacteriocins, the stress resistance to gastrointestinal tract environment and adhesive performance, were identified. Whole genome sequence of Lactobacillus plantarum KLDS1.0391 will be helpful for its applications in food industry.

The Effect of Lactobacillus actobacillus Peptidoglycan on Bovine ß-Lactoglobulin-Sensitized Mice via TLR2/NF-κB Pathway.

Our previous study reported that Lactobacillus acidophilus(L.acidophilus)  key laboratory of dairy science  (KLDS) 1.0738 had an effective impact on inhibiting ß-lactoglobulin (ß-lg) allergy. This study further investigated the anti-allergic activity of peptidoglycan (PGN) isolated from KLDS 1.0738. This study aimed to assess whether toll-like receptor 2 (TLR2)/NF-kappaB (NF-κB) signaling activated by PGN was responsible for reducing allergic inflammation.  Our data showed that administration of  L. acidophilus PGN inhibited IgE production and improved the Treg/Th17 balance toward a Treg response in a mouse model of ß-lg allergy. In addition, treating different doses L. acidophilus PGN to sensitized mice significantly increased TLR2 levels, along with enhancing NF-κB expression, especially in medium and high concentration (p<0.05). Further analysis revealed that the mRNA expression of TLR2 and NF-κB were positively correlated with the Foxp3 mRNA expression (p<0.05), but were negatively correlated with the RORγt mRNA expression in L. acidophilus PGN-treated group compared to allergy group (p<0.05). This study suggests PGN was similar to probiotics in preventing ß-lg allergy through regulating Treg/Th17 imbalance, and activation of TLR2/NF-κB signaling may be involved in this process.

Microencapsulation of Lactobacillus rhamnosus GG by Transglutaminase Cross-Linked Soy Protein Isolate to Improve Survival in Simulated Gastrointestinal Conditions and Yoghurt.

Microencapsulation is an effective way to improve the survival of probiotics in simulated gastrointestinal (GI) conditions and yoghurt. In this study, microencapsulation of Lactobacillus rhamnosus GG (LGG) was prepared by first cross-linking of soy protein isolate (SPI) using transglutaminase (TGase), followed by embedding the bacteria in cross-linked SPI, and then freeze-drying. The survival of microencapsulated LGG was evaluated in simulated GI conditions and yoghurt. The results showed that a high microencapsulation yield of 67.4% was obtained. The diameter of the microencapsulated LGG was in the range of 52.83 to 275.16 µm. Water activity did not differ between free and microencapsulated LGG after freeze-drying. The survival of microencapsulated LGG under simulated gastric juice (pH 2.5 and 3.6), intestinal juice (0.3% and 2% bile salt) and storage at 4 °C were significantly higher than that of free cells. The survival of LGG in TGase cross-linked SPI microcapsules was also improved to 14.5 ± 0.5% during storage in yoghurt. The microencapsulation of probiotics by TGase-treated SPI can be a suitable alternative to polysaccharide gelation technologies.

Identification of surface-associated proteins of Bifidobacterium animalis ssp. lactis KLDS 2.0603 by enzymatic shaving.

Bifidobacteria are commensal microorganisms of the human and animal intestinal tract, and their surface proteins can mediate bacterial communication and chemical sensing in the environment, as well as facilitate interactions between bacteria and the host. However, a systematic study of the outer surface-associated proteome of bifidobacteria has not been undertaken. In the present study, the proteins located on the surface of Bifidobacterium animalis ssp. lactis KLDS 2.0603 were systematically identified by a nongel proteomic approach, which consisted of the shaving of the bacterial surface with trypsin and an analysis of the released peptides by liquid chromatography-tandem mass spectrometry. A total of 105 surface-associated proteins were found, of which 15 proteins could potentially be involved in adhesion and interactions between bifidobacteria and the host. The proteins related to adhesion and interaction between bacteria and the host include pilus structure proteins (Fim A, Fim B), 10 moonlighting proteins, an NLP/P60 family protein, an immunogenic secreted protein, and a putative sugar-binding secreted protein. The results provide the basis for future studies on the molecular mechanisms of the interactions between bifidobacteria and the host.

Complete genome sequence of Bifidobacterium animalis subsp. lactis KLDS 2.0603, a probiotic strain with digestive tract resistance and adhesion to the intestinal epithelial cells.

Bifidobacterium animalis subsp. lactis KLDS 2.0603 (abbreviated as KLDS 2.0603) is a probiotic strain isolated from the feces of an adult human. Previous studies showed that KLDS 2.0603 has a high resistance to simulated digestive tract conditions and a high ability to adhere to intestinal epithelial cells (Caco-2). These two characteristics are essential requirements for the selection of probiotic bacteria. To explore the stress resistance mechanism to the digestive tract environment and the adhesive proteins of this strain, in this paper, we reported the complete genome sequence of KLDS 2.0603, which contains 19,469bp and encodes 1614 coding sequences(CDSs), 15 rRNA genes, 52 tRNA genes with 1678 open reading frames.

Multi-Cereal Beverage Fermented by Lactobacillus Helveticus and Saccharomyces Cerevisiae.

A novel multi-cereal-based fermented beverage with suitable aroma, flavor, and pH fermented by lactic acid bacteria and Saccharomyces cerevisiae was developed. Twenty-seven lactobacilli strains were screened for acid production (pH and titratable acidity) in a mixture of malt, rice, and maize substrates. It was found that Lactobacillus helveticus KLDS1.9204 had the greatest acid production among 27 lactobacilli tested. The fermentation performance of L. helveticus KLDS1.9204 was also assayed and the fermentation parameters were optimized using Plackett-Burman design and steepest ascent method. L. helveticus KLDS1.9204 showed good proteolytic capability, however, the strain could not utilize starch. The optimum substrate consisted of 50% malt (25 g/100 mL), 25% rice (20 g/100 mL), and 25% maize (30 g/100 mL). The inoculum was 5% with a ratio of S. cerevisiae to L. helveticus KLDS1.9204 of 2.5:1. The optimum temperature was 37 °C and the time was 22 h. Lastly, the quality of the multi-cereal-based fermented beverage was evaluated. This beverage was light yellow, transparent, and it tasted well with a pleasant acid and a unique flavor of cereals. The beverage was rich in free amino acids and organic acids. The pH and titratable acidity of the beverage were 3.5 and 29.86 °T, respectively. The soluble solids content of the beverage was 6.5 °Brix, and the alcohol content was 0.67%.

Genome-wide identification of small RNAs in Bifidobacterium animalis subsp. lactis KLDS 2.0603 and their regulation role in the adaption to gastrointestinal environment.

OBJECTIVE: Bifidobacteria are one of the predominant bacterial species in the human gastrointestinal tract (GIT) and play a vital role in the host's health by acting as probiotics. However, how they regulate themselves to adapt to GIT of their host remains unknown. METHODS: Eighteen bifidobacterial strains were used to analyze their adaptive capacities towards simulated GIT environment. The strain with highest survival rate and adhesion ability was selected for comparative genome as well as transcriptomic analysis. RESULTS: The Bifidobacterium animalis subsp. lactis KLDS 2.0603 strain was demonstrated to have the highest survival rate and adhesion ability in simulated GIT treatments. The comparative genome analysis revealed that the KLDS 2.0603 has most similar whole genome sequence compared with BB-12 strain. Eleven intergenic sRNAs were identified after genomes prediction and transcriptomic analysis of KLDS 2.0603. Transcriptomic analysis also showed that genes (mainly sRNAs targeted genes) and sRNAs were differentially expressed in different stress conditions, suggesting that sRNAs might play a crucial role in regulating genes involved in the stress resistance of this strain towards environmental changes. CONCLUSIONS: This study first provided deep and comprehensive insights into the regulation of KLDS 2.0603 strain at transcription and post-transcription level towards environmental.