抗植物病毒农药“病毒煞”的氨基酸成分分析

本文通过对抗植物病毒农药“病毒煞”的氨基酸成分进行分析,共含有１８种氨基酸,其中脯氨酸、谷氨酸、精氨酸和天冬氨酸含量较高,约占水解氨基酸总量的４７％;含有１９种游离氨基酸,脯氨酸含量最高,占游离氨基酸总量的５１％,说明氨基酸可能是其防病增产的有效成分之一。     

Effects of the timing of a culture temperature reduction on the comprehensive metabolite profiles of <Emphasis Type="Italic">Chlorella vulgaris</Emphasis>

This study investigated the effects of different temperature conditions on the comprehensive metabolite profiles of Chlorella vulgaris using gas chromatography–mass spectrometry coupled with multivariate statistical analysis. C. vulgaris cells cultivated at 20 °C were transferred to 10 °C incubators at different time points of cultivation [days 0 (TR0D), 7 (TR7D), and 14 (TR14D)], then they were cultivated at 10 °C until harvesting at day 21 to compare the growth and comprehensive metabolite profiles with those cultivated under a constant cultivation temperature of 20 °C (T20). There was no significant difference in algal cell growth between cultivation under the T20 and temperature reduction (TR) conditions. Algal fatty-acid profiles under TR were different from those of the T20 condition. Specifically, the contents of octadecanoic acid (C18:0), octadecenoic acid (C18:1), hexadecadienoic acid (C16:2), and octadecadienoic acid (C18:2) increased the most under TR0D. The relative levels of metabolites such as β-alanine, glutamine, glycine, isoleucine, proline, valine, and myo-inositol, which act as osmolytes, and bioactive compounds such as neophytadiene and ascorbic acid were increased under TR conditions on day 21. Among the metabolites, the contents of neophytadiene and ascorbic acid were further investigated, and the content of ascorbic acid was highest on day 14 under the TR7D condition, while the content of neophytadiene was highest on day 21 under the TR0D and TR14D condition. Therefore, we suggest that a TR from 20 to 10 °C could enhance the production in C. vulgaris cultures of bioactive fatty acids such as C18:1, C16:2, and C18:2 (TR0D), organic osmolytes such as β-alanine, glutamine, glycine, isoleucine, proline, valine, and myo-inositol (TR conditions), ascorbic acid (TR7D), and neophytadiene (TR0D and TR14D).     

Transfer of the plasmid RP1 in vivo in germ free mice and in vitro in gut extracts and laboratory media

Abstract: The frequency of conjugal transfer of the plasmid RP1 from two different Escherichia coli donor strains (HB101 and X7, Rif^R) to the same E. coli recipient strain (X7, Nal^R) was measured in vivo (germ free mice) and in vitro (intestinal extracts, caecal contents and laboratory liquid and agar media). The transfer frequencies of the plasmid from X7, Rif^R and HB101 in vivo were not significantly different from those obtained when using intestinal extracts or caecal contents. In contrast, compared to in vivo, a significant difference in frequency of transfer was obtained from one of the donors, X7, Rif^R when using laboratory liquid media ( P < 0.05) and a significant difference in frequency was noted for donor HB101 when using laboratory agar ( P < 0.01). When comparing the ratio of transfer frequency between the two different donors, the plasmid consistently transferred at a higher frequency in vivo and in in vitro caecal contents from X7, Rif^R than from HB101 ( P < 0.05). The same pattern was observed when using in vitro intestinal extracts ( P > 0.05). In contrast, when laboratory agar was used, the opposite occurred and the transfer was greater from HB101 than from X7, Rif^R ( P < 0.05). The transfer frequency in laboratory liquid media was highly variable from donor X7, Rif^R and no significant difference ( P > 0.05) could be seen between the two donors. We conclude that the intestinal extracts and caecal contents better reflect the natural environment than any of the laboratory media tested for the parameter investigated. Furthermore, it is shown that transfer using laboratory agar did not reflect in vivo conditions. The data supports the concept of using sub-samples of an ecosystem as a microcosm for modelling the ecosystem.     

动物脂肪组织中羟脯氨酸测定方法研究

本研究通过试验,提出了盐酸水解—氨基酸自动分析仪快速、准确测定动物脂肪组织中羟脯氨酸的分析方法,该方法适用于动物育种、选种,动物发育期生理生化变化研究和肉质检验等方面。     

Disabled‐1 is down‐regulated in clinical breast cancer and regulates cell apoptosis through NF‐κB/Bcl‐2/caspase‐9

Disabled‐1 (Dab1) is best known as an adaptor protein regulating neuron migration and lamination during development. However, the exact function of Dab1 in breast cancer is unknown. In this study, we examined the expression of Dab1 in 38 breast cancer paraffin sections, as well as 60 paired frozen breast cancer and their adjacent tissues. Our results showed that Dab1 was reduced in breast cancer, and its compromised expression correlated with triple negative breast cancer phenotype, poor differentiation, as well as lymph node metastasis. Functional analysis in breast cancer cell lines demonstrated that Dab1 promoted cell apoptosis, which, at least partially, depended on its regulation of NF‐κB/Bcl‐2/caspase‐9 pathway. Our study strongly suggests that Dab1 may be a potential tumour suppressor gene in breast cancer.     

甘肃、青海十个民族中苯硫脲尝味能力测定

本文用Harris和Kalmus改良阈值法对甘肃、青海两省汉、回、东乡、保安、藏、裕固、蒙古、撒拉、土、哈萨克等十个民族共计7008人进行了测定。以三号液为味盲界线。结果表明:l)各民族味盲发生率差异极显著(P<0.001),其中保安族味盲发生率是到目前为止我国大陆各民族中发现的仅高于黎族的民族;味盲总发生率与日本人相近。2)各民族总计中男性与女性味盲百分率无显著差异,但尝味阈值女性显著低于男性。3)色觉异常患者与尝味能力的关系与国内外其它学者结果不同,即味盲率和尝味阈值与色觉异常无关。     

用Beckman 121MB型氨基酸分析仪快速分析含硫氨基酸和色氨酸

蛋白质中胱氨酸、蛋氨酸和色氨酸在用盐酸水解时损失较大,常用过甲酸氧化法和碱水解法处理。采用文中方法分析时间短,分辨率高,半胱磺酸、甲硫氨酸砜和色氨酸的保留时间分别为５．３、１１．６和２０．４分钟。每分析一个样品需２６分钟,且基线平稳、重复性好、色谱图清晰。     

γH2AX foci formation in the absence of DNA damage: Mitotic H2AX phosphorylation is mediated by the DNA-PKcs/CHK2 pathway

Phosphorylated H2AX is considered to be a biomarker for DNA double-strand breaks (DSB), but recent evidence suggests that γH2AX does not always indicate the presence of DSB. Here we demonstrate the bimodal dynamic of H2AX phosphorylation induced by ionizing radiation, with the second peak appearing when G2/M arrest is induced. An increased level of γH2AX occurred in mitotic cells, and this increase was attenuated by DNA-PKcs inactivation or Chk2 depletion, but not by ATM inhibition. The phosphorylation-mimic CHK2-T68D abrogated the attenuation of mitotic γH2AX induced by DNA-PKcs inactivation. Thus, the DNA-PKcs/CHK2 pathway mediates the mitotic phosphorylation of H2AX in the absence of DNA damage.     

蛹虫草表型多态性对子实体产生及虫草菌素的影响

为选育高产子实体和虫草菌素的蛹虫草菌株,从野生蛹虫草中分离单孢子并进行分型,之后进行产子实体实验;同时对蛹虫草子实体进行了产孢结构的观察,并用高效液相色谱仪检测了子实体和培养基中的虫草菌素。结果表明,菌落背面颜色为橙铬色的菌株容易产生子实体;出发(原代)菌株所产子实体在形态上更接近野生蛹虫草,而角变株的子实体畸形;出发菌株产子实体能力要比该菌株未发生角变部分分离株和角变部分分离株都强。在虫草菌素的产量上也以出发菌株为高,表明表型多态性对蛹虫草产子实体和虫草菌素有很大的影响。这对于优势菌种的筛选和生产实践有借鉴意义。     

Exchange of Domain I from Bacillus thuringiensis Cry1 Toxins Influences Protoxin Stability and Crystal Formation

Influence of domain I exchange on the stability and production of Bacillus thuringiensis Cry1 protoxins as well as on the shape of inclusion and toxicity to Spodoptera exigua and Plutella xylostella larvae was investigated. Chimeric genes were prepared by exchanging the regions coding for domain I between Cry1Aa, Cry1Ab, Cry1Ac, Cry1C, and Cry1E. The AcCC chimera accumulated into bipyramidal inclusion bodies, whereas CEE produced round-shaped inclusion bodies, and ECC and AaEE protoxins produced small granules. AbEE and EAaAa did not produce any inclusion body and were visualized by immunodetection only. AcCC, CEE, ECC, and AaEE were stable to trypsin, whereas AbEE and EAaAa were not. Bioassays showed that the chimeras were not toxic in vivo. However, S. exigua larvae fed with the activated AcCC toxin displayed a lower growth rate. Received: 14 October 2000 / Accepted: 17 November 2000