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BACKGROUND/OBJECTIVES@#Tibetan tea is a kind of dark tea, due to the inherent complexity of natural products, the chemical composition and beneficial effects of Tibetan tea are not fully understood. The objective of this study was to unravel the composition of Tibetan tea using knowledge-guided multilayer network (KGMN) techniques and explore its potential antioxidant and hypolipidemic mechanisms in mice.MATERIALS/METHODS: The C57BL/6J mice were continuously gavaged with Tibetan tea extract (T group), green tea extract (G group) and ddH 2 O (H group) for 15 days. The activity of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) in mice was detected.Transcriptome sequencing technology was used to investigate the molecular mechanisms underlying the antioxidant and lipid-lowering effects of Tibetan tea in mice. Furthermore, the expression levels of liver antioxidant and lipid metabolism related genes in various groups were detected by the real-time quantitative polymerase chain reaction (qPCR) method. @*RESULTS@#The results showed that a total of 42 flavonoids are provisionally annotated in Tibetan tea using KGMN strategies. Tibetan tea significantly reduced body weight gain and increased T-AOC and SOD activities in mice compared with the H group. Based on the results of transcriptome and qPCR, it was confirmed that Tibetan tea could play a key role in antioxidant and lipid lowering by regulating oxidative stress and lipid metabolism related pathways such as insulin resistance, P53 signaling pathway, insulin signaling pathway, fatty acid elongation and fatty acid metabolism. @*CONCLUSIONS@#This study was the first to use computational tools to deeply explore the composition of Tibetan tea and revealed its potential antioxidant and hypolipidemic mechanisms, and it provides new insights into the composition and bioactivity of Tibetan tea.
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Objective@#To isolate the cariogenic Streptococcus mutans (Sm) strains and study the therapeutical effect of egg yolk antibody (IgY) of the Sm on dental caries development.@*Methods@#Sm strains were isolated from the children's dental plaque samples. Morphological, biochemical and molecular biological methods were applied to identify the serotype, acid producing and adhesion abilities of isolated Sm strains. After inactivation one of the Sm strains was used as antigen to immune laying hens to collect and extract the specific anti-Sm IgY. The rats were infected with Sm (serotype e). After 16 weeks of infection, all the rats were found developing dental caries. The rats were then randomly divided into two groups. The rats in experimental group were supplied with diet containing anti-Sm IgY while the rats in control group with normal IgY. All rats were sacrificed after another 8 weeks' observation. The degree of caries for each rat was assessed using Keyes' method.@*Results@#We isolated 7 Sm strains from the children's dental plaque samples in the present study. The numbers of serotype c, e, f, k were 3, 2, 0 and 2, respectively. All strains showed similar morphological and biochemical characters as standard UA159 Sm strain, and possessed strong capabilities of acid production and adherence. Interestingly, even the same serotypec strains, such as No.3 and No.7 strains, demonstrated significant difference on acid producing and adherence capabilities. After 16 weeks infection with serotype e strain, the rats' mandibular teeth were apparently decayed, and treatment with specific anti-Sm IgY obviously attenuated the development of caries in the experiment group rats (16.4±2.0) compared with that in the control group rats (30.2±9.3) (P<0.05) determined by Keyes' method.@*Conclusions@#Seven cariogenic Sm strains of different serotypes were isolated, which possesses similar morphology and biochemical characters. Although belonging to the same serotype strains they always show significant difference in acid-producing and adherencec apabilities. Further experiment provides evidences that the serotype e strain could obviously induce caries independently, and employment of specific anti-Sm IgY as passive immunotherapy additive might effectively inhibit the further development of dental caries.
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Objective To prepare an egg yolk antibody ( IgY) against the recombinant human A rotavirus VP8 and evaluate its biological characteristics .Methods The complete VP4 gene was used as the template to clone VP8 DNA fragment by PCR .The VP8 gene was then cloned into the vector pET 28a for ex-pression of VP8 protein in the prokaryotic system.The expression plasmid of pET28a-VP8,identified by DNA sequencing,was transformed into E.coli BL21 to induce the expression of protein by 0.5 mmol/L IPTG at 30℃.The purified and refolded recombinant VP 8 protein was used to immunize laying hens in combination with complete Freund′s adjuvant ( CFA ) .Anti-VP8 IgY antibodies were extracted from egg yolks by using water dilution-ultrafiltration assay and were further analyzed by SDS-PAGE,ELISA,Western blot and Dot blot assay,respectively.Results The recombinant VP8 protein was expressed in E.coli BL21 as an inclusion body and its molecular weight was about 35 ×10 3 .The VP8 protein was well refolded in a buffer containing Tris-HCl (pH8.0).The isolated anti-VP8 IgY antibodies showed a high titer of 1∶100 000 and a high stabil-ity under the condition of pH3-11 and temperature 25-65℃.Moreover,the anti-VP8 IgY antibodies specific-ally recognized the wild type human A rotavirus .Conclusion The prepared anti-VP8 IgY antibodies showed the advantages of high titer ,good specificity and stability .It might be used as the tool in further investigation for the prevention and treatment of diarrhea caused by human A rotavirus .