Tingtao Chen

The beneficial effect of exopolysaccharides from Bifidobacterium bifidum WBIN03 on microbial diversity in mouse intestine

BACKGROUND The structure of exopolysaccharides (EPS) produced by Bifidobacterium and their beneficial effects on human health have been fully studied, but only a few studies have investigated their influence on microbial diversity in the human/animal intestine. RESULTS The strain named Bifidobacterium bifidum WBIN03 with high growth rate and exopolysaccharide (EPS) yield was selected to study the effect of its EPS on modifying the intestinal microbiota of mice. The results indicated that EPS significantly increased the growth of lactobacilli and total anaerobic bacteria, and exerted their inhibition effect on the growth of enterobacteria, enterococci and Bacteroides fragilis. Denaturing gradient gel electrophoresis (DGGE) analysis indicated that the EPS significantly increased the diversity of total bacteria and lactobacilli, but significantly decreased the diversity of enterobacteria. When receiving a low dose of EPS, Bacteroidales sp./Lactobacillus sp. occupied the dominant position, and L. johnsonii, L. animalis and L. reuteri were identified as the dominant strains when receiving a high concentration of EPS. CONCLUSION The combination of viable cell count, DGGE and sequencing was used as an effective method to assess the microbial diversity in mouse intestine, and the benefit effect of EPS from B. bifidum WBIN03 on probiotics and antagonistic effect against pathogens would guaranteed the health of their hosts.

Evaluation of the Microbial Diversity in Amyotrophic Lateral Sclerosis Using High-Throughput Sequencing

More and more evidences indicate that diseases of the central nervous system have been seriously affected by fecal microbes. However, little work is done to explore interaction between amyotrophic lateral sclerosis (ALS) and fecal microbes. In the present study, high-throughput sequencing method was used to compare the intestinal microbial diversity of healthy people and ALS patients. The principal coordinate analysis, Venn and unweighted pair-group method using arithmetic averages (UPGMA) showed an obvious microbial changes between healthy people (group H) and ALS patients (group A), and the average ratios of Bacteroides, Faecalibacterium, Anaerostipes, Prevotella, Escherichia, and Lachnospira at genus level between ALS patients and healthy people were 0.78, 2.18, 3.41, 0.35, 0.79, and 13.07. Furthermore, the decreased Firmicutes/Bacteroidetes ratio at phylum level using LEfSE (LDA > 4.0), together with the significant increased genus Dorea (harmful microorganisms) and significant reduced genus Oscillibacter, Anaerostipes, Lachnospiraceae (beneficial microorganisms) in ALS patients, indicated that the imbalance in intestinal microflora constitution had a strong association with the pathogenesis of ALS.

Rapid detection of Campylobacter jejuni using fluorescent microspheres as label for immunochromatographic strip test

Campylobacter jejuni is a worldwide foodborne pathogen recognized as a leading cause of human gastrointestinal enteritis. A rapid, sensitive, and specific method is required to monitor food and water in cases of contamination by this pathogen. This report presents a novel immunochromatographic test (ICT) using fluorescent microspheres labeled with polyclonal antibodies of C. jejuni as the capture reagent dispensed onto the conjugate pad. Polyclonal antibodies against the outer membrane protein PEB1 of C. jejuni were used as the detective reagent at the test line, whereas the goat anti-rabbit IgG was used on the control line. PEB1 was obtained by gene cloning and expression to prepare its antibody. In this study, a simple and rapid ICT is reported for detecting C. jejuni for the first time with a detection limit of 106 CFU/ mL.

Reclamation of Chinese herb residues using probiotics and evaluation of their beneficial effect on pathogen infection.

Environmental pollution caused by herb residues and the huge waste of medicinal ingredients contained in herb residues hinder the development of traditional Chinese medicine enterprises. To solve this problem, several probiotics were tested, and Lactobacillus plantarum (HM218749) was finally selected for the reuse of herb residues of Jianweixiaoshi tablets. A mouse model of Helicobacter pylori infection was developed to evaluate the anti-H. pylori infection activity of the herb residue fermentation supernatant using a urease activity test, histological imaging, an enzyme-linked immunosorbent assay (ELISA) and denaturing gel gradient electrophoresis (DGGE). The results demonstrated that the herb residue fermentation supernatant successfully inhibited urease activity, slowed cell infiltration in the gastric area and significantly reduced the production of interleukin-6 (IL-6), IL-8 and TNF-α in the treatment group (p<0.01). In addition, the DGGE results indicated that the herb residue fermentation supernatant was beneficial for the recovery of the disturbed microbiota in the infected model to the normal condition, in which L. gasseri (GU417842.1) and L. johnsonii (HQ828141.1) were dominant in all groups. Therefore, the probiotics exhibited strong potential for the development of herb residues in this study, and the products showed strong potential in curing H. pylori infections.

Zn or O? An Atomic Level Comparison on Antibacterial Activities of Zinc Oxides.

For the first time, the influence of different types of atoms (Zn and O) on the antibacterial activities of nanosized ZnO was quantitatively evaluated with the aid of a 3D-printing-manufactured evaluation system. Two different outermost atomic layers were manufactured separately by using an ALD (atomic layer deposition) method. Interestingly, we found that each outermost atomic layer exhibited certain differences against gram-positive or gram-negative bacterial species. Zinc atoms as outermost layer (ZnO-Zn) showed a more pronounced antibacterial effect towards gram-negative E. coli (Escherichia coli), whereas oxygen atoms (ZnO-O) showed a stronger antibacterial activity against gram-positive S. aureus (Staphylococcus aureus). A possible antibacterial mechanism has been comprehensively discussed from different perspectives, including Zn(2+) concentrations, oxygen vacancies, photocatalytic activities and the DNA structural characteristics of different bacterial species.

Molecular identification of microbial community in surface and undersurface douchi during postfermentation.

To find the reason for fermentation failure of surface Douchi during postfermentation, the microbial communities in undersurface and surface samples were investigated using cell counting method and denaturing gradient gel electrophoresis (DGGE). The results showed that the microbial biomass in surface Douchi was obviously different from that in undersurface Douchi even sampled from the same fermentation tanks, and a 10- to 100-fold reduction of microbial cell counts in undersurface had been observed. The bacterial DGGE profile and principal component analysis (PCA) results indicated that only Lactococcus lacts subsp. lactis and Bacillus thermoamylovorans were detected from surface Douchi, while Lactococcus lacts subsp. lactis, Staphylococcus lentus and 2 uncultured strains occupied the dominant positions in undersurface Douchi; when amplified using Bacillus-specific primers, Bacillus thermoamylovorans, Bacillus subtilis, and Enterobacter sp. were found in undersurface Douchi, while only Bacillus thermoamylovorans were detected from surface Douchi; compared to the bacteria and Bacillus, the DGGE profiles and PCA plot of fungi indicated that the fungal community between surface and undersurface Douchi was similar and mainly composed by yeasts. In this study, we detected the microbial biomass and species in postfermentation stage of Douchi, and the various microbial diversity in undersurface and surface samples might be the cause of the fermentation failure in surface fermentation tanks.

In vitro and in vivo examination of anticolonization of pathogens by Lactobacillus paracasei FJ861111.1

Very limited information exists on the exclusion of pathogens by probiotics in the gut of the host challenged with pathogens. In this study, we tested probiotic characteristics in vitro and anticolonization ability of Lactobacillus paracasei FJ861111.1 in mice infected with selected pathogenic microorganisms. The in vitro results indicated that L. paracasei FJ861111.1 had a high survival in acidic conditions at pH 2.5 and bile salt concentration at 0.3%, and strong inhibition ability against common pathogens including Shigella dysenteriae, Staphylococcus aureus, Cronobacter sakazakii, Escherichia coli, and Candida albicans. The cell adhesion assays showed that L. paracasei FJ861111.1 exhibited strong adherence to HT-29 cells and excluded the adhesion of selected food-borne pathogens to HT-29 cells. The in vivo results showed that fermented milk with L. paracasei and viili (a Nordic yogurt product) significantly improved the population of total bacteria and of Lactobacillus in the feces of mice, and significantly inhibited the colonization of C. albicans to the intestines of mice post-C. albicans infection. Thus, it appears that this strain could be used as a probiotic organism for manufacturing functional fermented milk.

a novel method for screening of potential probiotics for high adhesion capability

To screen for potential probiotics with high adhesion capability, a chemostat model-based cultured human feces and denaturing gradient gel electrophoresis methods were applied, and the adhesion capability of the isolates was evaluated in vitro and in vivo. Lactobacillus plantarum (HM218749), Lactobacillus reuteri (EU547310), and Enterococcus faecalis (HM218543) were isolated from the slime on the chemostat wall, as these organisms could grow better at 37°C in an anaerobic environment and could resist harsh conditions (pH 1.5 and 0.30% bile salt). Lactobacillus plantarum, L. reuteri, and E. faecalis could adhere to HT-29 cells and reduce the adhesion of Shigella dysenteriae 2457, Staphylococcus aureus Cowan1, Enterobacter sakazakii 45401, and Escherichia coli 44102 to HT-29 cells. Moreover, the animal experiment showed that L. plantarum could adhere to mice intestine, increasing the number of lactobacilli and decreasing the number of enterococci.

Evaluation of the Antioxidative, Antibacterial, and Anti-Inflammatory Effects of the Aloe Fermentation Supernatant Containing Lactobacillus plantarum HM218749.1

Little work is done to develop Aloe vera (AV) using probiotics. To explore the potential benefits, the antioxidant effects and the antibacterial effects on foodborne pathogens of Aloe fermentation supernatant were evaluated in vitro. Our results indicated that the Aloe fermentation supernatant fermented by Lactobacillus plantarum HM218749.1 had very strong scavenging capacities of the DPPH (86%), O2 •− (85%), •OH (76%), and Fe2+ chelation (82%) and reducing powers (242.5 mg/L), and the inhibition zones for Salmonella typhimurium, Salmonella enteritidis, Shigella flexneri, Escherichia coli, Listeria monocytogenes, S. dysenteriae 301, Staphylococcus aureus Cowan1, and Propionibacterium acnes were 16, 15, 19, 20, 21, 20, and 27 mm. Moreover, the low concentration of Aloe fermentation supernatant had significantly reduced the production of IL-1β, TNF-α, and IL-6 in both mRNA and protein levels (P < 0.01). Therefore, the Aloe fermentation supernatant can be used as functional beverage or cosmetic ingredients to guard human intestinal health, delaying senescence, and prevent chronic diseases.

The non-cytotoxicity characterization of rebaudioside A as a food additive

To evaluate the cytotoxicity of high-purity rebaudioside A (reb A, 99.16%) as a food ingredient, a combination of several methods, including tetrazolium-based colorimetric assay (MTT), lactate dehydrogenase assay (LDH), enzyme-linked immunosorbent assay (ELISA), real-time PCR (qPCR), high-performance liquid chromatography (HPLC), and two-dimensional electrophoresis (2-DE) were used to test the cytotoxicity of reb A on the human cells HT-29 and T84, as well as liver and spleen cells from mice. The results indicated that no obvious changes in cellular viability, inflammatory cytokines yield, or protein yield were observed between the test group and the control group when different concentrations of reb A were used, suggesting that reb A is non-cytotoxic in vitro at the concentrations range tested (0.001-0.5%).