发酵香肠的工艺研究

以嗜酸乳杆菌和植物乳杆菌为发酵剂发酵香肠,对工艺进行了探讨。结果表明：嗜酸乳杆菌单一菌森发酵最佳工艺为３０℃,１０＾８ｃｆｕ／ｇ,２４－４８ｈ嗜酸乳杆菌和植物乳杆菌,以１：１组合时最佳工艺为３０℃１０＾７ｃｆｕ／ｇ,１８－２４ｈ。     

Effect of Lactobacillus reuteri on the Expression Profile of miRNAs in the Jejunum of Piglets

This study was conducted to investigate the effect of Lactobacillus reuteri on the expression of miRNAs in the jejunum of piglets. Six litters of healthy 1-day-old York×Rongchang piglets were selected and randomly divided into the two group,3 litters per group(n=27). The two groups were control group (daily orally adminitrated with 0.1% sterile peptone solution per piglet),and the LR group (daily orally administrated with 1.0×10¹⁰ CFU of L. reuteri per piglet), respectively. At 10 and 20 days of age, six piglets per group were selected for slaughter, respectively, and the jejunum samples were collected. After RNA extraction, the library was constructed and the miRNA expression profile of the jejunum was detected by Solexa high-throughput sequencing technology. Bioinformatics technology was used to conduct target genes prediction and functional analysis. The results showed that: 1) A total of 8 libraries were constructed and a total of 187 103 840 clean reads were obtained, of which the 22 nt length sequence accounted for the largest proportion; 2) Three hundred and fifty-four and 352 known miRNAs were respectively identified at 10 and 20 days of age, of which 329 miRNAs were co-expressed; 3) Differentially expressed (DE) miRNAs in the jejunum were found after L. reuteri administration, 7 and 9 DE miRNAs were obtained at 10 and 20 days of age,respectively. Notably, ssc-miR-218 was expressed differentially at two ages. 4) KEGG pathway analysis and target gene prediction on the differentially expressed miRNAs revealed that 10 221 target genes were enriched in 293 biological pathways, of which 66 were significantly enriched (P<0.05), including the MAPK signaling pathway and PI3K-Akt signaling pathway, which were known to regulate intestinal development and immune. 5) Six miRNAs were selected to validate the sequencing results by qRT-PCR, the qRT-PCR expression results corresponded well with those from the sequencing. The results indicates that L. reuteri may regulate intestinal health related pathways by influencing the expression of jejunal miRNAs.     

巨型艾美尔球虫感染对雏鸡肠道乳酸杆菌的影响

取200只红羽肉杂雏鸡,饲喂至8日龄,随机分为3个球虫卵囊剂量感染组(0.5×105、1.0×105和2.0×105个/羽),并设对照组;于感染后1、3、5、7 d,各组分别处死雏鸡5只,测定小肠中段乳酸杆菌的定植数量。结果表明:与对照组比较3个试验组雏鸡肠道的乳酸杆菌定植数量均有降低。其中试验Ⅰ组,在感染后1、3 d,肠道乳酸杆菌定植数对数值分别为(5.46±0.14)和(5.57±0.14),与对照组比差异不显著(P>0.05);感染5、7 d后,分别为(5.71±0.45)和(5.80±0.52),达到差异显著水平(P<0.05)。试验Ⅱ、Ⅲ组,在感染后1 d,达到差异显著水平(P<0.05)。感染后3、5、7 d,肠道乳酸杆菌定植数量对数值与对照组比较达到极显著水平(P<0.01)。试验证明大剂量球虫感染可明显降低雏鸡小肠段乳酸杆菌的定植数量。     

猪A组轮状病毒Vp7基因与乳酸菌非抗性表达载体的重组及在大肠杆菌中的表达

轮状病毒（Rotavirus，RV）属于呼肠孤病毒科（Reoviridae）、轮状病毒属（Rotaviras），作为婴幼儿和动物腹泻的主要病原，在世界范围内广泛流行，每年造成巨大损失。鉴于其危害严重且无有效治疗手段，世界卫生组织将RV疫苗列为最优先发展的疫苗项目之一，尤其是它的基因工程疫苗的研制更为重要。     

刺参池塘养殖系统中1株副干酪乳杆菌的分离及其生物学特性研究

本研究利用MRS培养基,从山东东营刺参(Apostichopus japonicus)养殖池塘环境中分离到56株乳酸菌.以刺参腐皮综合征2种重要致病菌灿烂弧菌(Vibrio splendidus)和假交替单胞菌(Pseudoalteromonas nigrifaciens)为指示菌,采用牛津杯法测定所分离的乳酸菌对2株...     

猪源肠道嗜酸乳杆菌的分离、鉴定与驯化

本文旨在分离筛选适于在猪肠道生长的嗜酸乳杆菌(Lactobacillus acidophilus)菌株。选用仔猪新鲜粪便,利用MRS培养基,以平板划线法分离纯化菌株;采用形态、生理生化和16 SrRNA基因序列分析对分离菌株进行鉴定;通过逐步提高培养基酸度、胆盐浓度和培养温度,对分离菌株进行驯化。结果表明:1)经分离纯化获得的菌株La-5,被鉴定为嗜酸乳杆菌。2)驯化后的菌株La-5c在pH=1.5~3时存活率比原始菌株La-5高出36%~44%,极低pH(1.5)条件下仍有37%的存活率。3)在0.03%~0.3%胆盐中的存活率为85%~90%,而原始菌株La-5为28%~53%。4)在50℃时的存活率为66.1%,而原始菌株La-50.01%。由此可见,与仔猪粪便分离纯化的嗜酸乳杆菌原始菌株La-5比较,驯化获得的菌株La-5c具有耐低pH、高浓度胆盐及高温的特性。     

猪传染性胃肠炎病毒纤突S蛋白干酪乳杆菌表达载体系统的构建

根据猪传染性胃肠炎病毒(TGEV)纤突(S)蛋白的全基因序列及表达载体质粒的基因融合特点,设计一对引物,进行PCR,获得含有TGEV S基因4个主要抗原位点的约2000 bp目的片段,将其分别与表达载体质粒pPG611.1和pPG612.1进行连接,通过电转化进入宿主菌Lacto-bacillus casei393细胞内,通过质粒提取、PCR鉴定、酶切鉴定和序列测定分析,表明TGEV S基因已成功插入到表达载体质粒中,获得了TGEV S蛋白干酪乳杆菌表达载体系统。     

中药提取剂对乳酸菌体外培养增殖的影响

本试验选用党参、黄芪、枸杞、山楂、女贞子和杜仲叶以煎煮法制备提取液进行乳酸杆菌体外增殖试验。试验结果显示,除枸杞外,其余5味中药均对乳酸杆菌有增殖作用,但以女贞子20～40mg/mL、黄芪20mg/mL、杜仲叶80mg/mL和党参80～100mg/mL的增殖效果显著(P<0.05),由此表明添加量对乳酸菌的增殖作用有较大影响。     

植物乳杆菌的生理功能和组学研究进展

植物乳杆菌是乳酸杆菌的一种,在自然界中广泛存在,尤其是各类发酵食品中。植物乳杆菌是人体肠道微生物的一员,由其生产的发酵食品的发酵作用与其对人体的益生作用使得植物乳杆菌逐渐成为基因组学、蛋白质组学、转录组学和代谢组学研究的模式微生物,阐明微生物环境适应性及发挥有益功能等的分子机制。本文综述了近年来植物乳杆菌的生理功能和组学研究进展,以期为研究者提供借鉴。     

乳清蛋白适度水解与其致敏性及益生菌生长的相关性

牛乳过敏问题是影响婴儿健康的重要问题,乳清蛋白中的主要过敏原为α-乳白蛋白和β-乳球蛋白,将乳清蛋白进行适度水解可以显著降低其致敏性。但是目前对于乳清蛋白的最适水解度还没有一个明确的评价标准。本研究从降低致敏性和促进益生菌（嗜酸乳杆菌08001）增殖角度建立乳清蛋白最适水解度的标准。结果表明：水解度为14.27%的乳清蛋白水解物符合本研究所要寻找的最适水解度乳清蛋白衡量标准,在此水解度下,乳清蛋白的致敏性降低较多,促嗜酸乳杆菌08001生长效果也较好。