为了进一步研究微生物富硒的能力,得到富硒能力较强的啤酒酵母,以啤酒酵母WX-01为出发菌,通过高浓度亚硒酸钠初筛,再经过常压室温等离子体(atmospheric and room temperature plasma,ARTP)诱变处理以及亚硒酸钠抗性平板筛选,观察菌株的...为了进一步研究微生物富硒的能力,得到富硒能力较强的啤酒酵母,以啤酒酵母WX-01为出发菌,通过高浓度亚硒酸钠初筛,再经过常压室温等离子体(atmospheric and room temperature plasma,ARTP)诱变处理以及亚硒酸钠抗性平板筛选,观察菌株的生长状况结合对其生物量与硒含量的测定,选育出一株富硒优势啤酒酵母。通过培养条件为添加质量浓度35 mg/L,加硒时间8 h,培养时间36 h,得到的酵母WX-1的生物量提高到(5192±36)mg/L,较原始菌株WX-01提高了201%,硒含量达到(1475±33)μg/g,较原始菌株提高了330%,其有机硒产量和转化率分别为7658μg/L和97.1%。扫描电镜分析酵母菌富集后表面有少量单质硒析出。另外红外光谱在特定区域出现不同强度的吸收峰表明酵母细胞参与了硒蛋白的合成。展开更多
Selenium protects cells from oxidative damage and reduces lipopolysaccharide （LPS）-induced expression of inflammatory cytokines. Because inflammatory cytokines induce growth depression, we hypothesized that selenium...Selenium protects cells from oxidative damage and reduces lipopolysaccharide （LPS）-induced expression of inflammatory cytokines. Because inflammatory cytokines induce growth depression, we hypothesized that selenium-rich yeast （SeY） would inhibit growth depression caused by LPS. Twenty Meishan weanling pigs [28 （s.d. 2 d）, 7.6 （s.d. 0.3 kg） body weight （BW）] were used in a 2×2 factorial design （n=5）. The main factors were dietary Se sources [selenium-rich yeast （SeY） vs. sodium selenite （SSe）] with supplement level at 0.3 mg Se/kg, and immunological stress （LPS vs. saline）. The experiment lasted for 28 d. On d 14 and d 21, half of pigs in each dietary treatment were intramuscularly injected with either 50 μg/kg BW LPS or an equivalent amount of sterile saline. Blood samples were collected at 3 h post-injection. There were no interactions between dietary Se sources and immunological stress on growth performance. LPS depressed average daily gain （ADG） （d 14-21, P〈0.05; d 21-28, P〈 0.01）, and elevated feed to gain ratio （F/G） （d 21-28, P〈0.05）, while SeY elevated ADG （d 0-14, P〈0.05; d 21-28 and d 0-28, P〈0.01）, and decreased F/G （P〈0.01）. Interactions were observed on interleukin-1β（IL-1β） and interleukin-6 （IL-6） from serum samples of d 14 and d 21 （P〈0.01）, as well as superoxide dismutase （SOD） and insulin like growth factor （IGF-1） of d 21 （P〈0.05）. In conclusion, SeY relieved the growth depression of piglets immunologically stressed by LPS, which maybe resulted from the decreased externalization of inflammatory cytokines and improved antioxidant status.展开更多
文摘为了进一步研究微生物富硒的能力,得到富硒能力较强的啤酒酵母,以啤酒酵母WX-01为出发菌,通过高浓度亚硒酸钠初筛,再经过常压室温等离子体(atmospheric and room temperature plasma,ARTP)诱变处理以及亚硒酸钠抗性平板筛选,观察菌株的生长状况结合对其生物量与硒含量的测定,选育出一株富硒优势啤酒酵母。通过培养条件为添加质量浓度35 mg/L,加硒时间8 h,培养时间36 h,得到的酵母WX-1的生物量提高到(5192±36)mg/L,较原始菌株WX-01提高了201%,硒含量达到(1475±33)μg/g,较原始菌株提高了330%,其有机硒产量和转化率分别为7658μg/L和97.1%。扫描电镜分析酵母菌富集后表面有少量单质硒析出。另外红外光谱在特定区域出现不同强度的吸收峰表明酵母细胞参与了硒蛋白的合成。
文摘Selenium protects cells from oxidative damage and reduces lipopolysaccharide （LPS）-induced expression of inflammatory cytokines. Because inflammatory cytokines induce growth depression, we hypothesized that selenium-rich yeast （SeY） would inhibit growth depression caused by LPS. Twenty Meishan weanling pigs [28 （s.d. 2 d）, 7.6 （s.d. 0.3 kg） body weight （BW）] were used in a 2×2 factorial design （n=5）. The main factors were dietary Se sources [selenium-rich yeast （SeY） vs. sodium selenite （SSe）] with supplement level at 0.3 mg Se/kg, and immunological stress （LPS vs. saline）. The experiment lasted for 28 d. On d 14 and d 21, half of pigs in each dietary treatment were intramuscularly injected with either 50 μg/kg BW LPS or an equivalent amount of sterile saline. Blood samples were collected at 3 h post-injection. There were no interactions between dietary Se sources and immunological stress on growth performance. LPS depressed average daily gain （ADG） （d 14-21, P〈0.05; d 21-28, P〈 0.01）, and elevated feed to gain ratio （F/G） （d 21-28, P〈0.05）, while SeY elevated ADG （d 0-14, P〈0.05; d 21-28 and d 0-28, P〈0.01）, and decreased F/G （P〈0.01）. Interactions were observed on interleukin-1β（IL-1β） and interleukin-6 （IL-6） from serum samples of d 14 and d 21 （P〈0.01）, as well as superoxide dismutase （SOD） and insulin like growth factor （IGF-1） of d 21 （P〈0.05）. In conclusion, SeY relieved the growth depression of piglets immunologically stressed by LPS, which maybe resulted from the decreased externalization of inflammatory cytokines and improved antioxidant status.
