转基因在苹果蠹蛾不育昆虫释放技术中的应用

使用不育昆虫释放技术是一项新兴的苹果蠹蛾Cydia pomonella(L.)防治方法,使用转基因得到不育雄蛾具有比传统辐射方法更多的优点。转基因技术通过使用基于piggyBac等转座子的质粒载体,并插入显性条件致死基因以培育遗传性别品系,同时插入荧光蛋白等标记基因来显示转基因的效果;在人工控制的发育条件,建立成熟的稳定苹果蠹蛾品系,用以最终的田间释放以达到防治的目的。     

犬瘟热病毒TN株血凝基因的克隆与序列分析

用RT PCR方法对分离的TN野毒株H基因进行了扩增 ,并将其克隆到pGEM T载体上 ,进行核苷酸序列测定。结果TN野毒株H基因ORF全长 1 ,81 5bp ,编码 60 4个氨基酸。与GenBank中己报道的 7个CDV毒株相比 ,H基因核苷酸序列的同源性在 92 %～ 99%之间 ,推导的H蛋白氨基酸序列的同源性在 91 %～ 99%之间。TN株H蛋白潜在的N 联糖基化位点为 8个 ,而Onderstepoort弱毒株H蛋白为 4个 ;其中N端第 1 9～ 2 1、 30 9～ 31 1、 5 8     

Winemaking of musts at high osmotic strength by thermotolerant yeasts

Fermentation performance of 15 thermotolerant Saccharomyces cerevisiae in three musts from dried grapes at 25, 30, and 40° brix was studied. When the osmotic strength was increased, the volatile acidity and the SO₂ production in the wines also increased: in the must with 40° brix, yeasts produce from 1.63 to 3.65 g acetic acid l^–1 and from 40 to 73.6 mg SO₂ l^–1 due to osmotic stress. From 9.75 to 13.40 ethanol v/v production is observed in must at 30°brix, whereas at 40°brix there is a clear detrimental effect.     

Regulation and mechanism of organic selenium on quorum sensing,biofilm, and antioxidant effects of Lactobacillus paracasei

Different organic compounds can have varying degrees of impact on the activity of Lactobacillus paracasei. The study focused on the impact and action mechanism of different organic selenium products on the bioactivity of two strains of L. paracasei. The growth, antioxidant activity, extracellular polysaccharide secretion, quorum sensing (QS), and biofilm formation of the strains before and after the addition of organic selenium crude products and three organic selenium standard were evaluated. The results showed that the addition of crude organic selenium promoted the various activities of the strain. l -selenocysteine had the strongest regulatory effect, with maximum GIM1.80 biofilm formation when it reached a critical concentration of 0.4 μg/mL; l -selenomethionine resulted in the highest activity of the signal molecule Auto inducer-2 of GDMCC1.155, when it reached a critical concentration of 0.4 μg/mL. The results of scanning electron microscopy demonstrated that the addition of organic selenium effectively improved the morphological structure of the two bacterial cells. Molecular docking revealed that the mechanism by which organic selenium regulates QS in Lactobacillus was achieved by binding two crucial receptor proteins (histidine protein kinase HKP and periplasmic binding protein LuxP) from specific sites. Furthermore, organic selenium products have a beneficial regulatory effect on the biological activity of L. paracasei. Overall, these findings provide a new alternative (organic selenium) for regulating the viability and beneficial activity of L. paracasei.     

乳杆菌活菌制剂对细菌性阴道病局部免疫的调节

目的检测正常人和细菌性阴道病(BV)患者治疗前后阴道局部细胞因子的变化,探讨乳杆菌活菌制剂对女性生殖道免疫的影响,为阴道微生态平衡与阴道黏膜免疫屏障的关系的研究提供一定的依据。方法用乳杆菌活菌制剂治疗BV,通过酶联免疫吸附试验法即ELISA法来检测BV患者治疗前后及正常健康妇女阴道局部细胞因子sIgA、IL-2、IL-13的水平。结果 sIgA、IL-13水平治疗前组较对照组明显升高(P<0.01),治疗后组较治疗前组水平下降(P<0.05),治疗后组较对照组水平升高(P>0.05);IL-2水平治疗前组较对照组明显降低,治疗后组较治疗前组明显升高(P<0.05),治疗后组较对照组下降(P<0.05)。结论 BV患者阴道局部免疫功能发生了改变;乳杆菌活菌制剂对BV患者阴道局部免疫具调节作用.     

A phosphopantetheinyl transferase gene essential for biosynthesis of n-3 polyunsaturated fatty acids from Moritella marina strain MP-1

A phosphopantetheinyl transferase (PPTase) gene (pfaE), cloned from the docosahexaenoic acid (DHA)-producing bacterium Moritella marina strain MP-1, has an open reading frame of 861 bp encoding a 287-amino acid protein. When the pfaE gene was expressed with pfaA-D, which are four out of five essential genes for biosynthesis of eicosapentaenoic acid (EPA) derived from Shewanella pneumatophori SCRC-2738 in Escherichia coli, the recombinant produced 12% EPA of total fatty acids. This suggests that pfaE encodes a PPTase required for producing n-3 polyunsaturated fatty acids, which is probably involved in the synthesis of DHA in M. marina strain MP-1.     

Structure and Biosynthesis of Two Exopolysaccharides Produced by Lactobacillus johnsonii FI9785

Exopolysaccharides were isolated and purified from Lactobacillus johnsonii FI9785, which has previously been shown to act as a competitive exclusion agent to control Clostridium perfringens in poultry. Structural analysis by NMR spectroscopy revealed that L. johnsonii FI9785 can produce two types of exopolysaccharide: EPS-1 is a branched dextran with the unusual feature that every backbone residue is substituted with a 2-linked glucose unit, and EPS-2 was shown to have a repeating unit with the following structure: -6)-α-Glcp-(1–3)-β-Glcp-(1–5)-β-Galf-(1–6)-α-Glcp-(1–4)-β-Galp-(1–4)-β-Glcp-(1-. Sites on both polysaccharides were partially occupied by substituent groups: 1-phosphoglycerol and O-acetyl groups in EPS-1 and a single O-acetyl group in EPS-2. Analysis of a deletion mutant (ΔepsE) lacking the putative priming glycosyltransferase gene located within a predicted eps gene cluster revealed that the mutant could produce EPS-1 but not EPS-2, indicating that epsE is essential for the biosynthesis of EPS-2. Atomic force microscopy confirmed the localization of galactose residues on the exterior of wild type cells and their absence in the ΔepsE mutant. EPS2 was found to adopt a random coil structural conformation. Deletion of the entire 14-kb eps cluster resulted in an acapsular mutant phenotype that was not able to produce either EPS-2 or EPS-1. Alterations in the cell surface properties of the EPS-specific mutants were demonstrated by differences in binding of an anti-wild type L. johnsonii antibody. These findings provide insights into the biosynthesis and structures of novel exopolysaccharides produced by L. johnsonii FI9785, which are likely to play an important role in biofilm formation, protection against harsh environment of the gut, and colonization of the host.     

Sequence Analysis of a 32-kb Region Including the Major Ribosomal Protein Gene Clusters from Alkaliphilic Bacillus sp. Strain C-125

Forty-one open reading frames (ORFs) were identified in a 32-kb DNA fragment of alkaliphilic Bacillus sp. C-125. A similarity search using the BSORF database found 37 ORFs with significant sequence similarity to B. subtilis RNA polymerase subunits, elongation factor G, elongation factor Tu, and ribosomal proteins. Each ORF product showed more than 70% identity to those of B. subtilis. Gene organization in the region of str, S10, spc, and the α cluster was highly conserved among three strains, C-125, B. subtilis, and B. stearothermophilus.