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关键词： anti-tumor immunity   mammals   vertebrates   pregnancy   trophoblast  

摘要： Observations on the morphological and functional similarity between embryonic or trophoblast tissues and tumors are very old. Over a period of time many investigators have created different hypotheses on the origin of cancerogenesis or tumor efficiency in relation to the host immune system. Some of these ideas have been rejected but many of them are still current. A presumption of the inefficiency of anti-tumor immunity in mammals due to the high similarity between trophoblast and embryonic cells to tumor cells is very real. The mechanisms for the escape of tumors from the immune response are very similar to the mechanisms for the escape of a fetoplacental unit from the maternal immune response. The similarity between these two mechanisms is so great that any randomness must be banished. At the same time, an incidence of malignant tumors and the types of more frequent tumors in non-mammalian vertebrates is significantly different to that in mammals. Lastly, the mechanisms of anti-tumor immunity in mammals are substantially different from the mechanisms of anti-tumor immunity in other classes of vertebrates. These facts indicate that the immune system of mammals during anti-tumor immune response is tricked by the similarity between tumor cells and trophoblast or other placental cells. From this aspect, our conclusion is that anti-tumor immunity failure in mammals can be defined as an immunoreproductive phenomenon, which is developed under the evolutionary pressure of autoimmunity and reproductive effectiveness.

关键词： 饲料   食品   数据分析   食品检验   介质   方法   农产品   微生物   检测   水平的   分析   微生物分析   细菌纲   抽样方法   分析方法   微生物学   试验媒体   验证   定义   溶血性   单核细胞增生性利斯特氏菌   精密度   试验   调查方法  

标准号: ISO 11290-1 AMD 1-2004

摘要： This is Amendment 1 to ISO 11290-1-1996 (Microbiology of food and animal feeding stuffs — Horizontal method for the detection and enumeration of Listeria monocytogenes — Part1: Detection method)

关键词： 农产品   分析   饲料   细菌纲   组分   培养基   定义   测定   食品检验   食品   食品测试   调查方法   微生物分析   微生物学   沙门氏菌属   抽样方法   测试   试验   验证  

标准号: ISO 6579 Technical Corrigendum 1-2004

摘要： The standard is about Microbiology of food and animal feeding stuffs — Horizontalmethod for the detection of Salmonella *** CORRIGENDUM 1

关键词： 朊病毒   表位   传染性海绵状脑病   基因  

摘要： 朊病毒（Prion）可引起的人和动物的传染性海绵状脑病（Transmissible SpongiformEncephalopathies,TSEs）。该致病因子具有与普通病原微生物不同的理化和生物学特性，至今其致病机理尚不完全明确。本研究利用基因克隆表达和生物信息学技术，结合病理组织学及实时荧光定量RT-PCR（Real-time RT-PCR）等方法，在对PrPc功能表位分析的基础上，对其主要结构蛋白合成肽的免疫学特性进行了分析，并对PrPc重组蛋白脑内接种金黄地鼠的生物学特性进行了探索，为今后进一步研究Prion的致病机理和检测技术奠定了基础，研究内容如下： 1．分别成功克隆了奶牛、牦牛、大熊猫、恒河猴、孔雀及珍珠鸡的PrPc基因，运用分子生物学软件对其和相关种属PrPc基因及氨基酸序列进行了序列比较、遗传进化和同源性分析，对PrPc结构蛋白的功能表位及二级结构进行了预测，获得了有关种属间PrPc基因结构多态性及功能表位生物学信息，为PRNP基因多态性与朊病毒病的连锁关系研究提供了基础数据。 2．利用Goldenkey分子生物学软件分析确定了奶牛PrPc的抗原功能表位，化学合成特定序列结构蛋白多肽，经鉴定后按照一定的分子比与载体蛋白匙孔嘁血蓝蛋白偶联，经检测后制备牛PrPc多肽兔多抗，并进行了免疫学特性检测。结果表明，所制备的特定表位结构蛋白多肽抗体经ELISA方法测定抗体效价达到1：10～8，经Western blotting试验检测，能够与PrPc重组结构蛋白和纯化的牛PrPc结合。提示该结构蛋白多肽抗体具有良好的免疫学特性，有望用于TSE检测试剂的研制。 3．采用原核表达系统对牛PrPc结构蛋白进行了成功表达，并利用结构蛋白多肽抗体进行了鉴定。结果表明：在37℃、OD为0.8时经IPTG（1.0mmol／L）诱导表达3h条件下，重组PrPc蛋白的表达量最高。经Western blotting方法检测，表达蛋白与多肽抗体反应性良好。结果提示：本研究成功制备了牛PrPc重组结构蛋白，该蛋白有望进一步用作Prion结构生物学的研究材料。 4．为了弄清PrPc重组结构蛋白的生物致病性及其对prpc基因表达的影响等生物学特性，进而为研究PrPc转化为PrPsc的选择压力条件提供生物学检测方法奠定基础。对试验组6只金黄地鼠脑内注射纯化后的PrPc重组结构蛋白（10μg/μl，3μl），对照组2只金黄地鼠用磷酸盐缓冲液（PBS）同法处理，临床观察记录；102天后将实验动物经眼球静脉放血处死，分别取小脑、脑干（Obex部位）、部分大脑经甲醛固定、制作石蜡切片、H.E.染色，光镜下进行组织病理学观察；取另一部分大脑提取总RNA利用实时荧光定量RT-PCR方法检测不同处理组金黄地鼠PrPc表达差异。结果表明：金黄地鼠脑内注射102天内，未见异常临床症状，试验组与对照组无明显差异；未见异常组织病理学变化；试验组和对照组金黄地鼠脑组织PrPc基因表达无显著差异。结果提示：通过PrPc重组蛋白在检测时间内未能引起地鼠脑组织海绵状病理变化，未能引起PrPcmRNA表达水平改变，为进一步研究PrPc重组蛋白结构生物学提供了基础数据。

关键词： 食品   微生物分析   验证   微生物学   实验室间试验   定义   污染   精密度   微生物   细菌计数方法   食品料   梭菌属   计数   饲料   计数方法(微生物学)   生化分析法   实验室试验   菌落计数技术  

标准号: DIN EN ISO 7937-2004

摘要： The project describes a horizontal method for the enumeration of viable Clostridium perfringens in products intended for human consumption or the feeding of animals.

关键词： 确认   饲料   芽胞杆菌   细菌纲   细菌计数方法   菌落计数技术   定义(术语)   食品   水平的   实验室间试验   微生物分析   微生物学   精密度   抽样方法   试验  

标准号: ISO 7932-2004

摘要： This International Standard specifies a horizontal method for the enumeration of viable presumptive Bacillus cereus by means of the colony-count technique at 30 ℃. It is applicable to — products intended for human consumption and the feeding of animals, and — environmental samples in the area of food production and food handling. NOTE In order to have a practicable test method, the confirmatory stage has been restricted to the typical aspect on MYP agar and the haemolysis test. Thus the term "presumptive" has been introduced in order to acknowledge the fact that the confirmatory stage does not enable the distinction of B. cereus from other closely related but less commonly encountered Bacillus species, such as B. anthracis, B. thuringiensis, B. weihenstephanensis, B. mycoides. An additional motility test may help to differentiate B. cereus from B. anthracis in cases where the presence of the latter is suspected.

关键词： NONFICTION  

摘要： Reviews the book "Wild Mammals of North America: Biology, Management and Conservation," 2nd ed. by George A. Feldhamer, Bruce C. Thompson and Joseph A. Chapman.

关键词： 饲料   悬浮液   试验室   生物试验   饮食   食品   规范(验收)   微生物   农产品   方法   试样制备   稀释方法   定义   微生物分析   试验   验证   微生物学   稀释  

标准号: ISO 21567-2004

摘要： This International Standard specifies a horizontal method for the detection of Shigella *** to the limitations discussed in the Introduction, this International Standard is applicable to- products intended for human consumption and the feeding of animals, and- environmental samples in the area of food production and food handling.

关键词： 微生物学   定义   食品   肠杆菌科   测定   农产品   试验   微生物分析   验证   浓缩   计数  

标准号: ISO 21528-1-2004

摘要： This part of ISO 21528 specifies a method, with pre-enrichment, for the detection of Enterobacteriaceae. It is applicable to — products intended for human consumption and the feeding of animals, and — environmental samples in the area of food production and food handling. Enumeration is carried out by calculation of the most probable number (MPN) after incubation at 37 ℃ (or 30 ℃) in liquid medium. This method is applicable — when the microorganisms sought are expected to need resuscitation before enrichment, and — when the number sought is expected to be in the range 1 to 100 per millilitre or per gram of test sample. A limitation on the applicability of this part of ISO 21528 is imposed by the susceptibility of the method to a large degree of variability (see Clause 11). note: 1) The temperature of 37 ℃ is generally used when the enumeration of Enterobacteriaceae is for a hygienic indicator. Alternatively, a temperature of 30 ℃ can be chosen when the enumeration of Enterobacteriaceae is conducted for technological purposes and includes psychrotrophic Enterobacteriaceae.

关键词： animal burrows   biology   cylinder   volume  

摘要： In this activity students examine burrow casts to learn about burrowing animals and practice their mathskills. Students compute the volume and average circumference of a burrow. They also determine whether a relationship exists between burrow volume and the size of the organism that created it. Students use science as inquiry as they analyze and interpret data generated by themselves and their classmates. [ABSTRACT FROM AUTHOR]