从动物毛中提取DNA研究初探

利用蛋白酶Ｋ分解毛发蛋白，并使用酚和氧仿除去蛋白质杂质方法提取毛中ＤＮＡ。结果测量获得的数据和曲线表明：动物脱落毛发以及从保存多年标本获得的毛发均可用来提取到具有一定纯度和数量的ＤＮＡ，完全可以满足聚合酶链式反应（ＰＣＲ）所需。     

DNA Methylation Pattern in Pronuclear-Stage Mouse Embryos: Effect of Oocyte Vitrification

This study was conducted to investigate the pattern of DNA methylation in pronuclearstage mouse embryos derived from vitrified-warmed oocytes.Mouse oocytes at metaphase Ⅱ (MⅡ) stage of meiosis were all...     

Practical capability of a DNA pool‐based genome‐wide association study using BovineSNP50 array in a cattle population

Genome‐wide association mapping for complex traits in cattle populations is a powerful, but expensive, selection tool. The DNA pooling technique can potentially reduce the cost of genome‐wide association studies. However, in DNA pooling design, the additional variance generated by pooling‐specific errors must be taken into account. Therefore, this study aimed to investigate factors such as: (i) the accuracy of allele frequency estimation; (ii) the magnitude of errors in pooling construction and in the array; and (iii) the effect of the number of replicate arrays on P‐values estimated by a genome‐wide association study. Results showed that the Illumina correction method is the most effective method to correct the allele frequency estimation; pooling errors, especially array variance, should be taken into account in DNA pooling design; and the risk of a type I error can be reduced by using at least two replicate arrays. These results indicate the practical capability and cost‐effectiveness of pool‐based genome‐wide association studies using the BovineSNP50 array in a cattle population.     

Comparison of the Value of Pulsed-field Gel Electrophoresis,Random Amplified Polymorphic DNA and Amplified rDNA Restriction Analysis for Subtyping Taylorella equigenitalis

Eight strains of Taylorella equigenitalis were identified by a polymerase chain reaction using a primer pair specific to the 16S rDNA of T equigenitalis. These eight strains were chosen because they had previously been shown to represent eight distinct genotypes by pulsed-field gel electrophoresis analysis after separate digestion of the genomic DNA with ApaI or NotI. The eight strains could be classified into six or seven types by random amplified polymorphic DNA analysis using different kinds of primers. Amplified rDNA restriction analysis after separate digestion with five restriction enzymes, including AluI and MboI, of the 1,500 bp fragments of rDNA amplified by polymerase chain reaction did not discriminate the genomic variations among the eight strains of T equigenitalis. Thus, pulsed-field gel electrophoresis was shown to discriminate these eight organisms better than random amplified polymorphic DNA analysis, while amplified rDNA restriction analysis was found to be unsuitable for subtyping T equigenitalis.     

利用DNA条形编码探讨云南野柞蚕的分类学地位

2001年在云南曲靖发现的野生柞蚕(云南野柞蚕,A.pernyiwild)拥有一些与放养型柞蚕(A.pernyi)不同的特性。测定了云南野柞蚕线粒体细胞色素酶C亚基I基因5′端的部分片段(658 bp,GenBank:EU532613),并利用该DNA条形编码探讨其分类学地位。基于Kimura-2-Parameter计算的4个放养型柞蚕品种之间的平均遗传距离仅0.003,而云南野柞蚕与放养型柞蚕之间的遗传距离为0.016,小于已确定分类学地位的放养型柞蚕与印度野蚕(A.rolyii)之间的遗传距离(0.028),但与家蚕(B.mori)同其祖先中国野桑蚕(B.mandarinaChina)之间的遗传距离相近(0.015)。NJ树中云南野柞蚕与放养型柞蚕也最先聚在一起,从分子水平证实其仍属于柞蚕种。初步认为,云南野柞蚕可以考虑成为柞蚕种的一个亚种——野柞蚕亚种。     

Detection of γ-H2AX,a Biomarker for DNA Double-strand Breaks,in Urinary Bladders of N -Butyl- N -(4-Hydroxybutyl)-Nitrosamine-Treated Rats

To evaluate the potential role of DNA repair in bladder carcinogenesis, we performed an immunohistochemical analysis of expression of various DNA repair enzymes and γ-H2AX, a high-sensitivity marker of DNA double-strand breaks, in the urothelium of male F344 rats treated with N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN), a bladder-specific carcinogen. Our results clearly demonstrated that γ-H2AX aggregation was specifically generated in nuclei of bladder epithelial cells of BBN-treated rats, which was not found in untreated controls or mesenchymal cells. γ-H2AX-positive cells were detected not only in hyperplastic and neoplastic areas but also in the normal-like urothelium after BBN treatment. These data indicate that γ-H2AX has potential as a useful biomarker for early detection of genotoxicity in the rat urinary bladder. To the best of our knowledge, this is the first report demonstrating expression of γ-H2AX during bladder carcinogenesis.     

First Steps Towards an Understanding of a Mode ofCarcinogenic Action for Vanadium Pentoxide

Inhalation of vanadium pentoxide clearly increases the incidence of alveolar/bronchiolar neoplasms in male and female B6C3F1 mice at all concentrations tested (1, 2 or 4 mg/m³), whereas responses in F344/N rats was, at most, ambiguous. While vanadium pentoxide is mutagenic in vitro and possibly in vivo in mice, this does not explain the species or site specificity of the neoplastic response. A nose-only inhalation study was conducted in female B6C3F1 mice (0, 0.25, 1 and 4 mg/m³, 6 h/day for 16 days) to explore histopathological, biochemical (α-tocopherol, glutathione and F2-isoprostane) and genetic (comet assays and 9 specific DNA-oxo-adducts) changes in the lungs. No treatment related histopathology was observed at 0.25 mg/m³. At 1 and 4 mg/m³, exposure-dependent increases were observed in lung weight, alveolar histiocytosis, sub-acute alveolitis and/or granulocytic infiltration and a generally time-dependent increased cell proliferation rate of histiocytes. Glutathione was slightly increased, whereas there were no consistent changes in α-tocopherol or 8-isoprostane F2α. There was no evidence for DNA strand breakage in lung or BAL cells, but there was an increase in 8-oxodGuo DNA lesions that could have been due to vanadium pentoxide induction of the lesions or inhibition of repair of spontaneous lesions. Thus, earlier reports of histopathological changes in the lungs after inhalation of vanadium pentoxide were confirmed, but no evidence has yet emerged for a genotoxic mode of action. Evidence is weak for oxidative stress playing any role in lung carcinogenesis at the lowest effective concentrations of vanadium pentoxide.     

鸡柔嫩艾美耳球虫3-1E和CDPK双抗原DNA疫苗的免疫保护效果观察

将构建的含鸡柔嫩艾美耳球虫(Eimeria tenella)CDPK和3-1E双抗原的真核重组质粒proEC,在14日龄和21日龄分别免疫AA肉鸡,28日龄感染5×104个E.tenella孢子化卵囊,观察其免疫保护效果.结果显示,攻虫后1周,与proC组相比,proEC组能显著增强淋巴细胞转化和血清抗体水平(P＜0.05);与proE组和proC组相比,proEC组卵囊产量最低但差异不显著(P＞0.05),其相对增重低于proE组和proC组.结果表明,proEC双抗原DNA疫苗对E.tenella攻虫表现出一定双抗原协同保护效应.     

DNA barcoding for identification of cryptic species in the field and existing museum collections: a case study of Aethomys and Micaelamys (Rodentia: Muridae)

DNA barcoding has been proposed as a method for species identification. However, this method has been criticised for its over-reliance on a single mitochondrial gene. In this study, four mitochondrial gene regions and one nuclear gene region were used to investigate their different abilities to identify tissue associated with museum specimens of Aethomys chrysophilus, Aethomys ineptus and Micaelamys namaquensis. Aethomys chrysophilus and the more recently elevated A. ineptus are indistinguishable on morphological grounds; however, their ranges are largely parapatric with only one syntopic locality currently known. All of the mitochondrial gene regions were able to separate M. namaquensis from A. chrysophilus and A. ineptus, but they varied in their abilities to resolve differences between A. chrysophilus and A. ineptus. The sequence results identified a specimen from KwaZulu-Natal that was misclassified and should have been identified as A. ineptus. Seven specimens that had not been reclassified following the elevation of A. ineptus to species level were identified as A. ineptus. Individuals of A. chrysophilus from Malawi could not be classified as either A. chrysophilus or A. ineptus, and may be a hybrid or a new, distinct species. This study indicates that DNA barcoding may be used to separate M. namaquensis from A. chrysophilus and A. ineptus, and although it was not able to separate A. chrysophilus and A. ineptus, it did indicate specimens from Malawi may be a new cryptic species.