| Summary: | 博士 === 靜宜大學 === 食品營養學系 === 101 === part 1
Today, refined foods and many sugar-containing beverages, make the tooth apt to form the dental plaque, lead to oral cavity disease including dental caries, periodontitis and periodontal disease. The aim of the present study was to investigate the in vitro ability of selected probiotics to inhibit growth and biofilm formation of cariogenic bacterium Streptococcus mutans. In this project, we screened lactic acid bacteria (LAB) strains (n=120) isolated from the healthy human saliva, infant stool and obtained from Bioresources Collection and Research Center (BCRC). The antimicrobial activity of LAB was evaluated using S. mutans strains by agar spot and co-culture method in vitro. We determined the effect of heating and the dilution factors (2- and 4-fold) on the antagonistic activity of LAB. The antagonistic substances in spent culture suspension (SCS) of LAB were precipitated by ammonium sulfate and chloroform extraction to characterization of protein and liphilic fractions. In co-culture method, the results showed that the SCS of heating treatement from three LAB strains had significantly highly antimicrobial activities. LAB strains 13-1 and 13-4 from oral saliva were identified as Lactobacillus pentosus by API 50CHL kit. The other strain was L. crispatus BCRC 14618 (LCR01). The potential antimicrobial substances were produced by L. pentosus 13-4 that might lipophilic proteins. Additionally, we suggested that the mechanism of anti-biofilm formation by Lactobacillus strains is associated with sucrose-dependent cell–cell adhesion and gtfC level of glucosyltransferases (Gtfs) in biofilm. We hope that the native LAB strain screened in this research can be applied as make the resistant decayed tooth products in processing food or chewing gums.
part 2
It knows that probiotics can improve the balance of intestinal microflora and enhance the host’s health. Some studies indicated that the high γ- aminobutyric acid (GABA) was produced by the fermentation with lactic acid bacteria (LAB), and GABA also could modulate blood pressure. Laboratory predecessor was to evaluate the high production of GABA of the purple sweet potato yogurt (PSPY) fermented by the multispecises LAB strains that applied to anti-hypertensive effect in vivo. The results showed that the spontaneously hypertensive rats (SHR) decreased systolic blood pressure and diastolic blood pressure after feeding yogurt for 8 weeks. The aim of this study was to further investigate the effects of LAB fermented PSPY on cardiac protection in SHR. Six-week-old male SHR were separated randomly into four groups. They were fed individually with sterile water, captopril and different doses (10% and 100%) of PSPY for 8 weeks. Age-matched, Wistar Kyoto (WKY) rats were used as normal control. The myocardial architecture and key components of the inflammatory, hypertrophic, apoptotic and survival pathway in the excised left ventricle from SHR were measured by histopathological analysis and Western blotting. The major findings of the present study can be summarized as following: (1) PSPY reduced cardiac fibrosis in SHR rats through the suppression of TLR-4-related inflammatory pathway. (2) PSPY might suppress the hypertrophic factors (ANP and BNP) and inhibite both the concentric and eccentric hypertrophy determining molecules (p-PKC-α, CaMKII, and p-ERK5) as well as enhance the p-NFAT-3. (3) the compensative IGFIR and IGFIR-dependent survival signaling components (p-Akt and p-PI3K) were all highly restore enhanced both in SHR-10% and 100% PSPY groups. Therefore, the cardiac apoptotic effects of SHR rats were totally reversed by the orally administration of PSPY. The cardioprotective effect of GABA-riched PSPYcan be attributed to not only antioxidant and antihypertensive properties but also improvement of the cardiac inflammation, hypertrophy and apoptosis in hypertensive rats. We believed that combined orally administration of PSPY with pharmaceutical in hypertensive treatments.
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