Chromate reducing and plant growth promoting activities of psychrotrophic Rhodococcus erythropolis MtCC 7,905.

A psychrotrophic bacterial strain resistant to 300 mg l(-1) of Cr(6+) was isolated from metal contaminated soil samples from a site situated in the Indian Himalayan Region. Based on 16 S rRNA analysis the isolate showed maximum similarity to Rhodococcus erythropolis. Rhodococcus erythropolis MTCC 7,905 reduced substantial amounts of Cr(6+) to Cr(3+) at 10 degrees C and showed plant growth promotion. The isolate offer promise as inoculant to promote plant growth of pea (Pisum sativum) in the presence of toxic Cr(6+) concentration. To the best of our knowledge this is the first report on a psychrotrophic strain belonging to species R. erythropolis and its functional characterization to reduce Cr(6+ )and promote plant growth at low temperature.     

Protein-protein- and protein-RNA-binding properties of the movement protein and VP25 coat protein of Apple latent spherical virus

To elucidate the mechanism of Apple latent spherical virus (ALSV) movement, various properties of its cell-to-cell movement protein (MP) were analyzed. ELISA and blot overlay assays demonstrated that the MP bound specifically to ALSV virions and in particular to one of the three coat proteins (VP25) but not to the other two coat proteins (VP20 and VP24). Mutational analyses have revealed that the MP contains two domains with independent VP25-binding activity (amino acid residues 1-188 and 189-281). Furthermore, nucleotide-binding experiments showed that the MP and VP25 bound to single-stranded RNA (ssRNA) and ssDNA without any sequence specificity, but these two proteins did not bind to double-stranded RNA (dsRNA) and dsDNA. The MP contains three potentially independent single-stranded nucleic acid-binding domains between amino acid residues 95-188, 189-281 and 277-376. The MP demonstrated cooperative and VP25 demonstrated non-cooperative binding to ssRNA in gel-retardation analyses. The cooperative RNA binding of the MP became non-cooperative when MP and VP25 were tested together in competition binding experiments, even though a sufficient amount of the MP for fully cooperative RNA binding the MP was supplied. The roles of the MP and VP25 interactions and nucleic acid binding activities in ALSV movement are discussed.     

牛蒡根4种提取物体外抗肿瘤活性的比较研究

目的:研究牛蒡根4种提取物体外抗肿瘤活性。方法:以系统溶剂分离法分别提取牛蒡根的石油醚、氯仿、乙酸乙酯、正丁醇部位。采用MTT法检测4种提取物对人乳腺癌细胞MCF-7、人胃腺癌细胞BGC-823、小鼠肝癌细胞HepA、肉瘤细胞S180和小鼠脾淋巴细胞生长的抑制作用。结果:牛蒡根石油醚、氯仿、乙酸乙酯3种提取物对MCF-7细胞和BGC-823细胞在体外有一定生长抑制作用;牛蒡根4种提取物对HepA细胞、S180细胞和小鼠脾淋巴细胞在体外有一定的生长抑制作用。结论:牛蒡根石油醚、氯仿、乙酸乙酯提取物体外具有一定的抗肿瘤活性,这种作用与增强细胞免疫活性无关。     

木尘提取液诱发体外培养BALBA/c-3T3细胞微核和多核

为探讨木尘的诱变性,选择硬木和软木各一种,分别为榉木和桦木,制备成木尘水提取液和有机提取液,进行BALB/c-3T3细胞微核和多核诱导试验.结果显示榉木尘和桦木尘两种提取液均存在细胞毒性,并可引起BALB/c-3T3细胞微核和多核细胞率的明显升高,剂量反应关系成立.说明榉木尘和桦木尘两种提取液均具有诱变性.     

Toxicity assessment of contaminated soils from an antitank firing range

Explosives are released into the environment at production and processing facilities, as well as through field use. These compounds may be toxic at relatively low concentrations to a number of ecological receptors. A toxicity assessment was carried out on soils from an explosive-contaminated site at a Canadian Forces Area Training Center. Toxicity studies on soil organisms using endpoints such as microbial processes (potential nitrification activity, dehydrogenase activity, substrate-induced respiration, basal respiration), plant seedling and growth (Lactuca sativa and Hordeum vulgare), and earthworm (Eisenia andrei) growth and reproduction were carried out. Results showed that 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX) was the principal polynitro-organic compound measured in soils. Soils from the contaminated site decreased microbial processes and earthworm reproduction; whereas plant growth was not significantly reduced. Toxicity to aquatic organisms and genotoxicity were also assessed on soil elutriates using Microtox (Vibrio fischeri), growth inhibition of algae (Selenastrum capricornutum), and SOS Chromotest (Escherichia coli). Results indicated that soil elutriates were generally not toxic to bacteria (Microtox) and algae. However, genotoxicity was found in a number of soil elutriate samples. Thus, the explosive-contaminated soils from the antitank firing range may represent a hazard for the soil organisms. Nevertheless, the global toxicity might have partially resulted from HMX as well as from other (not identified) contaminants such as heavy metals.     

火焰原子吸收光谱法测定猪血提取物中铁的含量

目的：建立火焰原子吸收光谱法测定猪血提取物中铁含量,为制订科学合理的猪血提取物的质量标准提供依据。方法：样品经过湿法消解,采用火焰原子吸收光谱法测定铁含量。结果：铁在0~2.5μg/ml浓度范围内线性关系良好,r=0.9998;方法检出限低,精密度高,重现性好,平均回收率为103.5%（n=9）;RSD为4.1%。结论：该方法准确、灵敏,可用于测定猪血提取物中铁的含量。     

Comparative study of the insecticidal activity of a high green plant (Spinacia oleracea) and a chlorophytae algae (Ulva lactuca) extracts against Drosophila melanogaster fruit fly

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栽培与野生羌活中4种化合物含量及抗炎作用比较

目的:比较栽培与野生羌活中4种化合物含量以及抗炎作用。方法:应用高效液相色谱(HPLC)法测定栽培与野生羌活中羌活醇、异欧前胡素、阿魏酸、佛手柑内酯的含量。复制二甲苯致小鼠耳廓肿胀模型和角叉菜胶致大鼠足跖肿胀模型,观察栽培与野生羌活水提液与醇提液对炎症模型动物肿胀度的影响。结果:栽培羌活所含4种成分含量大多高于野生羌活。野生羌活(班玛、壤塘、康定、西宁)、栽培羌活(岷县、渭源)水提液可显著抑制二甲苯致小鼠耳廓肿胀,其中栽培羌活(渭源)水提液效果最好;野生羌活(班玛、阿坝、壤塘、康定、西宁)醇提液、栽培羌活(岷县、渭源)醇提液可显著抑制角叉菜胶致大鼠足跖肿胀,其中栽培羌活(岷县)醇提液效果最好。结论:栽培羌活在化学成分含量及抗炎效果方面均等同于或强于野生品。