数字差异显示法在猪早期胚胎基因表达分析上的应用

借助于NIH生物信息中心Unigene里的数字差异显示软件平台,分析了猪植入前后早期胚胎发育9个EST文库的105 227个ESTs,筛选出了104个差异表达ESTs,对已知功能的差异表达基因进行GO分类分析,发现这些差异基因参与了广泛的生物功能和过程。同时,这些差异表达ESTs的聚类分析结果显示,体外和体内发育的囊胚基因表达存在较大的差异。对这些差异表达ESTs表达模式的分析结果显示,猪植入前早期胚胎发育阶段基因呈振荡模式表达,其中线粒体和核糖体相关基因的表达在囊胚中的表达丰度要明显高于其他阶段。表达数字差异显示的结果能为猪早期胚胎发育机理的研究提供线索。     

Further characterization of diabetes mellitus and body weight loss in males of the congenic mouse strain DDD.Cg-Ay

The A^y allele at the agouti locus causes obesity and promotes linear growth in mice. However, body weight gain stops between 16 and 17 weeks after birth, and then, body weight decreases gradually in DDD.Cg-A^y male mice. Body weight loss is a consequence of diabetes mellitus, which is genetically controlled mainly by a quantitative trait locus (QTL) on chromosome 4. This study aimed to further characterize diabetes mellitus and body weight loss in DDD.Cg-A^y males. The number of β-cells was markedly reduced, and plasma insulin levels were very low in the DDD.Cg-A^y males. Using a backcross progeny of DDD × (B6 × DDD.Cg-A^y) F₁-A^y, we identified one significant QTL for plasma insulin levels on distal chromosome 4, which was coincidental with QTL for hyperglycemia and lower body weight. The DDD allele was associated with decreased plasma insulin levels. When the DDD.Cg-A^y males were housed under three different housing conditions [group housing (4 or 5 DDD.Cg-A^y and DDD males), individual housing (single DDD.Cg-A^y male) and single male housing with females (single DDD.Cg-A^y male with DDD.Cg-A^y or DDD females)], diabetes mellitus and body weight loss were most severely expressed in individually housed mice. Thus, the severity of diabetes and body weight loss in the DDD.Cg-A^y males was strongly influenced by the housing conditions. These results demonstrate that both genetic and nongenetic environmental factors are involved in the development of diabetes mellitus and body weight loss in the DDD.Cg-A^y males.     

Veterinary antimicrobial-usage statistics based on standardized measures of dosage

In human medicine, the defined daily dose is used as a technical measure of drug usage, which is independent of the variations in the potency of the active compound and the formulation of the pharmaceutical product—therefore providing a measure of the relative importance of different drugs. A national system of animal defined daily doses (ADD) for each age-group and species has been defined in VetStat (the Danish national system monitoring veterinary therapeutic drug use). The usage is further standardized according to the number of animals in the target population, acquired from production data on the national level or on herd size by species and age in the Danish central husbandry register (CHR). Statistics based on standardized measures of VetStat data can be used for comparison of drug usage between different herds, veterinary practices, or geographic regions (allowing subdivision by animal species and animal production class, route of administration, disease categories, season and geographic location). Individual statistics are available as interactive reports to the control authorities, farmers and veterinary practitioners by a secure access to the database. The ADD also is used in pharmaco-epidemiogical research and to assist in the interpretation of resistance-surveillance data.     

Resistance in the highly DDT-resistant 91-R strain of Drosophila melanogaster involves decreased penetration,increased metabolism,and direct excretion

Resistance to 4,4′-dichlorodiphenyltrichloroethane (DDT) in the 91-R strain of Drosophila melanogaster is extremely high compared to the susceptible Canton-S strain (>1500 times). In addition to enhanced oxidative detoxification, the 91-R strain also has a reduced rate of DDT penetration, increased levels of reductive and conjugative metabolism, and substantially more excretion than the Canton-S strain. Contact penetration of DDT was ∼30% less with 91-R flies, which also had significantly more cuticular hydrocarbons and a thicker, more laminated cuticle compared to Canton-S flies, possibly resulting in penetration differences. DDT was metabolized ∼1.6-fold more extensively by 91-R than Canton-S flies, resulting in dichlorodiphenyldichloroethane (DDD), two unidentified metabolites and polar conjugates being formed in significantly greater amounts. 91-R flies also excreted ∼4-fold more DDT and metabolites than Canton-S flies. Verapamil pretreatment reduced the LD₅₀ value for 91-R flies topically dosed with DDT by a factor of 10-fold, indicating that the increased excretion may involve, in part, ATP-binding cassette (ABC) transporters. In summary, DDT resistance in 91-R is polyfactorial and includes reduced penetration, increased detoxification and direct excretion.