排序方式: 共有92条查询结果,搜索用时 15 毫秒
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S. MOHAPATRA T. CHAKRABORTY A.K. PRUSTY P. DAS K. PANIPRASAD K.N. MOHANTA 《Aquaculture Nutrition》2012,18(1):1-11
Six iso‐nitrogenous (350 g protein kg?1) and iso‐caloric (4100 kcal kg?1) diets with or without probiotics supplementation namely T1 (Basal feed (BF) without probiotics; control), T2 (BF + Bacillus subtilis and Lactococcus lactis), T3 (BF + L. lactis and Saccharomyces cerevisiae), T4 (BF + B. subtilis and S. cerevisiae), T5 (BF + B. subtilis, L. lactis and S. cerevisiae) and T6 (BF + heat‐killed bacteria of B. subtilis, L. lactis and S. cerevisiae) were fed to Labeo rohita fingerlings (6.0 ± 0.06 g) for 60 days in triplicate tanks (30 fish per tank). In all probiotic‐supplemented diets, the probiotic concentration was maintained at 1011 cfu kg?1 feed. After 60 days of culture, the fish fed combination of three probiotics at equal proportion (T5) had higher (P < 0.05) growth, protein efficiency ratio, nutrient retention and digestibility and lower (P > 0.05) feed conversion ratio over other treatment groups. Total heterotrophic bacterial population in intestine was drastically reduced on 15th and 30th days of sampling than the initial value (0 day of sampling) for T3, T4 and T5 groups. Except T6, the gut colonization of respective probiotics, which were supplemented through the diets, was also increased up to 30 days of culture of fish and thereafter remained constant. 相似文献
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C‐I Chang C‐F Lee J‐M Tsai C‐C Wu L‐H Chen S‐C Chen K‐J Lin 《Journal of fish diseases》2014,37(8):719-728
A selective and differential medium termed ‘LG agar’ was developed for the isolation and presumptive identification of Lactococcus garvieae that results in black colonies with red halos. In this study, all 14 strains of L. garvieae and only 9 of the 148 strains representing 38 other species were able to grow on the LG agar. The nine viable strains on LG agar plates (including Enterococcus faecalis, Enterococcus faecium, Lactococcus lactis, Vibrio fluvialis, Vibrio furnissii, Vibrio mimicus and Vibrio salmonicida) were further differentiated from L. garvieae by various colours or colony features. Colonies isolated from the mixing culture and the infected giant sea perch using LG agar plates were all positively identified as L. garvieae by conventional tests and 16S rDNA sequencing. Furthermore, LG agar discriminated capsulated strains of L. garvieae, which were believed to be correlated with pathogens of fish and shellfish, from non‐capsulated ones by colony appearances. The specificity and differentiating ability of LG agar suggest that this medium displays considerable potential for primary isolation and presumptive identification of L. garvieae from pathological and environmental samples. 相似文献
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根据乳酸乳球菌密码子的偏好性,在不改变编码蛋白的基础上,优化设计并合成枯草芽孢杆菌磷脂酰肌醇特异性磷脂酶C基因,将其与大肠埃希菌 乳酸乳球菌穿梭质粒pAMJ399连接,构建重组质粒pAMJ399 PIPLC,并电转化至乳酸乳球菌中进行诱导表达。SDS PAGE分析显示:重组蛋白以可溶性蛋白的形式分泌于胞外,分子质量约35 ku,与预期蛋白大小一致。重组蛋白在PI 李斯特氏菌显色平板上显现明显的乳白色晕圈,证明重组蛋白具有酶活性,磷脂酰肌醇特异性磷脂酶C(PI PLC)在重组乳酸乳球菌中成功获得表达。通过优化培养条件,以2%转接量,在含有1%红霉素抗性的GM17液体培养基中,于32 ℃静止培养24 h,测得培养基上清液中PI PLC的浓度为1.092 μg·mL-1。 相似文献
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本试验旨在构建能表达猪繁殖与呼吸综合征病毒(PRRSV)ORF5基因的重组质粒。用疑似患猪繁殖与呼吸综合征(PRRS)病猪的脾脏、肺脏病料提取RNA,根据PRRSV ORF5基因设计1对引物,进行RT-PCR扩增,将ORF5目的基因克隆到pMD19-T载体中,得到pMD19-ORF5重组菌。根据测序结果和表达载体特点,设计1对带有NcoⅠ和XbaⅠ酶切位点的引物,扩增目的片段(dORF5),将其分别与pProEXHTb载体、pNZ8149载体连接,得到HTb-dORF5/DE3和pNZ8149-dORF5/NZ3900重组菌,分别用IPTG和Nisin诱导,再进行SDS-PAGE和Western blotting分析。结果显示,HTb-dORF5/DE3重组菌在1.5 mmol/L IPTG诱导时表达量最高,通过SDS-PAGE和Western blotting分析,在约22 ku处有特异性条带,且具有反应原性;pNZ8149-dORF5/NZ3900重组菌在20 ng/mL Nisin诱导时表达量最高,通过SDS-PAGE和Western blotting分析,在约19 ku处有特异性条带,间接免疫荧光试验有特异性绿色荧光。本研究成功构建重组质粒HTb-dORF5和pNZ8149-dORF5并获得表达,这为进一步研制预防PRRS疫苗奠定坚实基础。 相似文献
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质粒消除是鉴定质粒和获得无质粒菌株的重要方法,是乳酸菌进行遗传学改造所需的一项重要技术。试验采用高温和消除剂结合的方法,对乳酸乳球菌镉抗性菌株进行质粒消除,探讨温度、消除剂吖啶橙的用量和作用时间对乳酸乳球菌镉抗性质粒消除的影响。结果表明,39℃高温可以质粒消除,而37和41℃均无此效果;独自吖叮橙作用未获得质粒消除菌株;39℃高温-吖啶橙同时作用比高温-吖啶橙交替作用消除率高,而39℃高温-20μg·mL-1吖啶橙共同作用12d,消除率可达98%。根据消除结果,以疑似功能性质粒为模板,进行PCR扩增,获得预期片段,进一步证实了其功能。 相似文献
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重组植物甜蛋白马宾灵的食品级乳酸乳球菌诱导表达系统的构建 总被引:1,自引:1,他引:0
为了将马宾灵(MabinlinⅡ)直接应用于功能性食品中,通过对MabinlinⅡ基因进行有目的的剪切重组,将重组MabinlinⅡ基因插入到食品级表达载体中,经电击转化和乳糖筛选获得重组的食品级乳酸乳球菌,构建了重组植物甜蛋白马宾灵(MBL-ABH)的食品级乳酸乳球菌诱导表达系统。结果表明,该食品级诱导表达系统经乳酸链球菌素(Nisin)诱导后所表达的目的蛋白的含量较低,Western-blot检测表明MBL-ABH成功的在食品级乳酸乳球菌中表达。本研究扩展了植物甜蛋白马宾灵在食品方面的应用,有望开发出能够避免添加食糖类物质的功能性食品。 相似文献
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乳酸菌NICE系统是目前较理想的可控制蛋白质生产的食品级诱导表达系统,而乳酸菌分泌表达异源蛋白比细胞质表达更优越。本研究将以pVE5524为模板PCR扩增的1.5 kbSPUsp45-NucA-CWAM6-t1t2基因克隆到食品级细胞内诱导表达载体pRNA48上,构建成食品级细胞壁锚定表达载体pRNV48,与宿主菌L.lactisNZ9000共同构成乳酸乳球菌食品级细胞壁锚定诱导表达系统。为检测该系统的功能,将铜绿假单胞菌融合外膜蛋白基因OprF/H克隆进pRNV48中,并检测了OprF/H的表达量和免疫原性。 相似文献
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