肉及肉制品中空肠弯曲菌的污染情况调查

我们对辽宁地区肉及肉制品进行弯曲杆菌属检查,发现12.9%(23/177)的样品为弯曲杆菌属阳性.经API Campy鉴定系统鉴定,其中26.1%(6/23)为空肠弯曲菌(C.jejuni)阳性,同时发现1株大肠弯曲菌.该调查证实,辽宁地区进出口的肉及肉制品中,存在空肠弯曲菌的污染,如果销售不当或再加工卫生不良,会对消费者的健康构成潜在威胁.     

JSRV衣壳蛋白单克隆抗体的制备及免疫学鉴定

经纯化的JSRV-CA融合蛋白乳化后免疫Balb/c小鼠,四免后,取其脾细胞与SP2/0骨髓瘤细胞经杂交瘤技术进行融合．最终获得了三株稳定分泌单克隆抗体的细胞系．同时,分段克隆绵羊肺腺瘤病毒ca基因并构建原核表达质粒,在E． coli BL21中诱导表达．以获得的三株抗JSRV-CA蛋白的单克隆细胞分泌的McAb为一抗,应用Western blot对分段表达的CA蛋白进行肽探针扫描,初步鉴定了三株单抗识别的线性表位,并应用非竞争性ELISA法测定了三株单抗的功能性亲和常数．为建立特异性的病原诊断方法、分析CA蛋白的功能及疫苗设计奠定了基础．     

Isolation and identification of lactic acid bacteria from Tarag in Eastern Inner Mongolia of China by 16S rRNA sequences and DGGE analysis

Tarag is a characteristic fermented dairy product with rich microflora (especially lactic acid bacteria), developed by the people of Mongolian nationality in Inner Mongolia of China and Mongolia throughout history. One hundred and ninety-eight samples of Tarag were collected from scattered households in Eastern Inner Mongolia, and total of 790 isolates of lactic acid bacteria (LAB) were isolated by traditional pure culture method. To identify these isolates and analyze their biodiversity, 16S rRNA gene sequences analysis and PCR-DGGE were performed respectively. The results showed that 790 isolates could be classified as 31 species and subspecies. Among these isolates, Lactobacillus helveticus (153 strains, about 19.4%), Lactococcus lactis subsp. lactis (132 strains, about 16.7%) and Lactobacillus casei (106 strains, about 11.0%) were considered as the predominated species in the traditional fermented dairy products (Tarag) in Eastern Inner Mongolia. It was shown that the biodiversity of LAB in Tarag in Inner Mongolia was very abundant, and this traditional fermented dairy product could be considered as valuable resources for LAB isolation and probiotic selection.     

土霉素菌渣源酵母菌的筛选及其培养条件的优化

【背景】随着制药行业的蓬勃发展,中国每年产生大量的抗生素菌渣,已造成了不可忽视的环境污染和资源浪费等问题。由于抗生素菌渣中含有丰富的蛋白质等有机物质,利用其蛋白质等进行二次生产或将成为解决抗生素菌渣处理问题的一种有效方法。【目的】从土霉素菌渣中筛选出天然酵母菌菌株,并利用土霉素菌渣作为酵母菌生长的主要培养基成分,通过其培养条件的优化,实现土霉素菌渣的资源化利用。【方法】以土霉素菌渣为样品,运用稀释涂布法进行酵母菌的筛选,通过其形态学观察和18S rRNA基因序列分析等方法对菌株进行鉴定。通过单因素试验与Box-Behnken Design试验结合,对培养条件进行优化,确定筛选菌株在以土霉素菌渣为主要成分培养基中的最佳生长条件。【结果】筛选的土霉素菌渣源酵母菌为一株希腊接合囊酵母菌(Zygoascus hellenicus)Y1,其最佳培养条件为:土霉素菌渣添加量为5%,葡萄糖添加量为0.5%,接菌量为2%,在pH 5.0、32℃、160r/min条件下培养24h。【结论】筛选到一株希腊接合囊酵母菌Y1,该菌能够很好地利用土霉素菌渣进行生长,实现了土霉素菌渣的资源化利用,大大减少了菌渣的...     

Diversity and distribution of CYP gene family in Bactrian camel

Cytochrome P450 (CYP) enzymes belong to a superfamily of monooxygenases which are phase I enzymes responsible for the first pass metabolism of about 90% of drugs in animals. However, these enzymes are often polymorphic and metabolism of the same drug in different species or different individuals is influenced by genetic and non-genetic factors. Bactrian camels are capable of survival in harsh living environments, being able to consume diets that are often toxic to other mammals and can tolerate extreme water and food deprivation. The aim of this study was to investigate whether the Bactrian camel’s special metabolic pathways and unique detoxification capabilities are attributable to particularities of the CYP gene family. The Bactrian camel’s whole genome sequencing data were systemically analyzed and annotated, and then, CYP gene family was searched from the whole protein database and compared with CYP gene families of cattle, horse, chicken, and human. The total of 63 CYP gene copies were found in Bactrian camel’s whole genome and were classified into 17 families and 38 subfamilies. Among them, 9 multi-gene families were found, and CYP2, CYP3, and CPY4 have 27, 6, and 7 subfamilies, accounting for 43, 10, and 11% in camel CYP gene, respectively. In comparison with cattle, chicken, horse, and human, the distribution of CYP gene subfamilies in camel is different, with more CYP2J and CYP3A copies in the Bactrian camel, which may contribute to the Bactrian camel’s specific biological characteristics and metabolic pathways. Comparing to the cow, horse, chicken, and human CYP genes, the distribution of CYP gene subfamilies is distinct in the Bactrian camel. The higher copy number of CYP2J gene and CYP3A gene in Bactrian camel may be the important factors contributing to the distinct biological characteristics and metabolic pathways of Bactrian camels for adaptation to the harsh environments.     

麦芽糖的改性及其化学修饰胰蛋白酶的研究

目的:通过高碘酸钠氧化法以麦芽糖修饰胰蛋白酶,检验此方法是否能够改善胰蛋白酶的稳定性.方法:采用高碘酸钠改性麦芽糖,使其中具有能够与酶分子中氨基结合的醛基,从而在一定条件下化学修饰胰蛋白酶.结果:改性麦芽糖的最佳条件为,高碘酸钠浓度0.05g/mL,高碘酸钠与麦芽糖质量比1.1∶1,初始pH 1.0,反应时间3h,反应温度30℃;修饰胰蛋白酶的最佳条件为,pH6.0,改性麦芽糖与胰蛋白酶质量比1∶1,修饰温度4℃,修饰时间24h;在最佳条件下修饰酶后,pH在8.9～10.0时,原酶活力与修饰酶活力分别下降了其最高活力的15.8%和9.8%;将酶置于50℃ 2h后,原酶与修饰酶分别保留了其置于4℃ 2h后活力的88.7%和94.7%.结论:该方法能够提高胰蛋白酶的耐碱稳定性和热稳定性.     

Improvement of Geomechanical Properties of Bio-remediated Aeolian Sand

Aeolian sand is widely distributed in the desert. It is susceptible to wind erosion because it consists of fine particles that lack cohesion between them. Wind erosion of Aeolian sand, dune migration, and dust storms in deserts affect the environment and infrastructure severely. Conventional chemical methods for lessening the effect of wind erosion are environmentally unfriendly. This paper examines Aeolian sand bio-remediated by microbially induced calcite precipitations (MICPs). The geomechanical properties of the Aeolian sand remediated by MICP were tested to explore its behavior as a desert bio-crust. The results indicated that a bio-crust of Aeolian sand with suitable strength required 7 days for formation. The remediated Aeolian sand had an average unconfined compression strength of 0.66 MPa and an average inner friction angle of 36° at a bacterial concentration in the OD₆₀₀ range of 0.5–0.8. These findings indicate that formation of bio-crust could serve as protection against desert erosion. The particle characteristics and the porosity of Aeolian sand play an important role in the formation of the bio-crust. Crust from bio-remediated well-graded, high-porosity soil is stronger than crust from bio-remediated, poorly graded, low-porosity soil, given that both soils have the same bacteria concentration.