聚-ε-赖氨酸高产菌株的筛选及其发酵工艺的初步研究

利用亚甲基蓝平板初筛、摇瓶复筛,从土壤中筛选了一株聚-ε-赖氨酸(ε-PL)高产菌株,ε-PL摇瓶产量大于2g/L,经初步鉴定该菌株为白色链霉菌(Streptomyces albulus)。对该菌株发酵生产ε-PL的培养基成分进行初步研究表明:葡萄糖是最好的碳源,酵母粉和硫酸铵是最佳的复合氮源,在优化培养基下,ε-PL摇瓶产量达到3.9g/L。     

Host Age Preference Behavior in <Emphasis Type="Italic">Aphidius ervi</Emphasis> Haliday (Hymenoptera: Aphidiidae)

Many parasitoid species have preference for certain stages of hosts to parasitize but the underlying behavioral mechanisms of such preference are still poorly understood, making it difficult to evaluate host-parasitoid interactions and their effects on the success of biological control programs. Here, we report our work on a parasitoid Aphidius ervi Haliday on the pea aphid Acyrthosiphon pisum (Harris). We show that with the increase of host age, female parasitoids are more likely to encounter and to attack their hosts but the hosts develop increasingly greater defensive capabilities. Encounter almost always triggers attack attempt; however, increasing attack attempts do not proportionally lead to ovipositor probings and increasing ovipositor probings do not proportionally translate into ovipositions. These asymmetric responses may be interpreted as that A. ervi females prefer to parasitize older aphids for higher fitness return but those aphids can better defend themselves, and as a consequence, A. ervi females may achieve the highest gain by attacking aphids of intermediate ages. We suggest that A. ervi females forage in a manner consistent with the optimal foraging theory, trading off host handling time with fitness returns.     

嗜热四膜虫可变剪接基因鉴定及功能分析

可变剪接是产生蛋白质组多样性和调节基因表达的重要机制,相关研究在高等真核生物中开展较多,而在单细胞真核生物中则较少,尤其是单细胞原生动物纤毛虫中,仅有少量报道。本文基于单细胞模式原生动物嗜热四膜虫种大量转录组数据,对其可变剪接基因进行了鉴定及分析。在嗜热四膜虫中共鉴定到2 894个可变剪接位点,涉及到2 698个可变剪接基因,可分为四类。考虑到转录本拼接的准确性,选择了其中464个与基因组预测模型完全一致的可变剪接基因进行深入分析,其中生长(growth)时期、饥饿(starvation)时期、接合生殖(conjugation)时期特异性的可变剪接基因分别为49个、79个和135个。对可变剪接基因的功能进行分析表明其涉及的功能广泛且显著富集于蛋白激酶过程,提示可变剪接基因在嗜热四膜虫蛋白磷酸化和信号传导中具有重要作用。     

Characterization and potential function of a novel pre‐implantation embryo‐specific RING finger protein: TRIML1

Members of the super‐class of zinc finger proteins are key regulators in early embryogenesis. Utilizing in silico mining of EST Databases for pre‐implantation Embryo‐Specific Zinc Finger Protein Genes, we characterized a novel zygotic mouse gene—tripartite motif family‐like 1 (TRIML1), which expresses in embryo before implantation. Knocking down of TRIML1 resulted in the fewer cell number of blastocysts and failture to give rise to neonates after embryo transfer. The binding partner of TRIML1, Ubiquitin‐specific protease 5 (USP5), was identified by yeast two‐hybrid screening assay. The interaction was confirmed by GST pull‐down and coimmunoprecipitation analysis. The role of TRIML1 in ubiquitin pathway during the development stage of mouse blastocyst was further discussed. Mol. Reprod. Dev. 76: 656–664, 2009. © 2009 Wiley‐Liss, Inc.     

乙型肝炎病毒(HBV)体内外对单个核细胞白细胞介素-1和白细胞介素-2诱生活性影响的研究

本研究用PAP法、胸腺细胞增殖法、脾细胞增殖法,分别检测16例体外HBV感染的骨髓单个核细胞与16例慢性乙型肝炎患者体内感染的骨髓单个核细胞(MNCs)中的HBcAg和白细胞介素-1(IL-1)、白细胞介素-2(IL-2)的诱生活性(以△cpm值表示)。结果显示,体外HBV感染组与体内HBV感染组骨髓MNCs中HBcAg检出率分别为50％和43.7％。本实验结果表明,HBV在体外感染骨髓MNCs,且与体内自然感染相符,但光镜下未观察到致细胞病变效应(CPE)。体外感染组与体内感染组IL-I和IL-2活性均较对照组明显下降(P<0.01)。且细胞中HBcAg检出阳性者较阴性者下降更为明显(P<0.01)。IL-1和IL-2诱生活性降低与HBV侵染免疫细胞及其在细胞内复制有密切关系,从而提示,IL-1和IL-2降低可能影响HBV的清除而引起慢性化过程。     

螺旋藻多糖的药理作用研究

螺旋藻多糖（Ｐｏｌｙｓａｃｃｈａｒｉｄｅ ｏｆ Ｓｐｉｒｕｌｉｎａ）是从螺旋藻中提取的一种无毒的天然产物,具有多种生物学活性。为进一步探讨螺旋藻多糖的作用,本文以小鼠为动物模型,观察极大藻多糖对小鼠生物功能的影响。螺旋藻多糖可以提高受γ射线致死剂量照射的小鼠３０天内的存活率促进小鼠多能干细胞和造血祖细胞的增殖和分化;促进受到辐射损伤的小鼠造血系统的恢复,增强小鼠的抗辐射能力。螺旋藻多糖可以提高小鼠     

Protective effects of cynaroside on oxidative stress in retinal pigment epithelial cells

Cynaroside is a flavonoid compound proved to possess antioxidant activity, but its protective effect on age‐related macular degeneration still remains unclear. In this study, the protective effects of cynaroside on oxidative stress and apoptosis in retinal pigment epithelial (RPE) cells induced by hydrogen peroxide (H₂O₂) were investigated. Results showed that cynaroside effectively attenuated the decrease of cell activity induced by H₂O₂. The total reactive oxygen species can be remitted by decreasing malondialdehyde level, as well as increasing glutathione level, and superoxide dismutase and catalase activities. In addition, Western blot analysis indicated that cynaroside protected ARPE‐19 cells from apoptosis through downregulation of caspase‐3 protein activation which was controlled by the upstream proteins Bcl‐2 and Bax. It was finally proved that cynaroside could enhance the antioxidant and antiapoptotic ability in ARPE‐19 cells by promoting the expression of p‐Akt.     

人BMP4基因的克隆及其原核表达载体的构建

以成熟人胎盘组织为材料来源,克隆人BMP-4基因的全长cDNA,经过PCR扩增后与pMD18-T载体连接,构建pMD18-T-BMP4克隆质粒.酶切后回收小片段与表达载体pET-22b的多克隆酶切位点连接,构建原核表达载体pET22b-BMP4,酶切及测序鉴定重组子.重组质粒转化至感受态的Rosseta宿主菌,经IPTG诱导表达,SDS-PAGE检测蛋白表达情况.结果显示,从胎盘组织中成功地克隆到人BMP4基因,与NCBI中公布的序列100％相符合,原核表达载体pET22b-BMP4转化至Rosseta构建表达菌体,经IPTG诱导后电泳分析可见重组蛋白表达的条带.