Environmental source of mycobacteriosis in a California swine herd.

Between July 1985 and April 1986, mycobacterial lymphadenitis was recorded in six of 2407 slaughter pigs from a commercial swine herd in which the majority of pigs were raised in confinement. Records showed that all six affected pigs had access to dirt-floored pens at least 81 days prior to slaughter. The mycobacteriosis lesion rate for pigs exposed to dirt pens was 9.4% while in nonexposed pigs the lesion rate was zero. The risk associated with movement of pigs from concrete floored pens to dirt pens was evaluated by a field trial. In the field trial, two litters (5 of 15 pigs) exposed to dirt pens at 12-24 days of age but none of nine nonexposed litters (39 pigs) developed lesions. Mycobacterium avium-complex bacteria were recovered from both exposed litters (9 of 15 pigs) but from none of nine nonexposed litters. Serovars of M. avium-complex isolated from trial pigs included 1, 4, 8, 9, the dual serovar 4/8, and an untypable serovar. Incense-cedar bark (Calocedrus decurrens) used as a flooring material in the pens was demonstrated to be a potential source of M. avium-complex serovar 9. The dual serovar 4/8 and an untypable M. avium-complex were isolated from the dirt-floored pens. No evidence of cross-transmission of M. avium-complex infection was detected. The sporadic pattern of mycobacteriosis observed in the herd probably resulted from infrequent exposure to a common environmental source.     

抗绵羊进行性肺炎病毒单克隆抗体杂交瘤细胞株的建立

用提纯的OPPV细胞抗原免疫BALB/c小鼠脾脏与SP2/0小鼠骨髓细胞融合,融合率为70%,以ELISA双抗体夹心法进行检测,阳性率为20%,经过有限稀释法克隆出1A₆、2B₈、1G₃、2G₄4株分泌抗OPPV抗原的单克隆体杂交瘤细胞株.选择抗体分泌滴度高的1A₆细胞进行了较详细的研究,结果表明,其核内染色体数为96～110条,抗体属性为IgG1,轻链为K链,IFA试验表明产生的McAb对OPPV有特异性,细胞传30代并在液氮中保存半年后复苏仍能稳定地分泌抗OPPV McAb,细胞分泌抗体的ELISA滴度腹水为6.4×10⁴,上清为640,McAb经硫基乙醇还原后在SDS-PAG上呈现2条区带,一条为重链部分,MW50000,另一条为轻链部分,MW为25000.     

苹果果皮细胞膜结构变化与虎皮病的关系

国光苹果在贮藏过程中,果皮内α—法尼烯不断积累,60天左右达最大值,后随共轭三烯的迅速增加而下降。与此同时,果皮中丙二醛积累,组织相对电导率增加。抗氧化剂二苯胺能显著降低果皮中丙二醛积累,阻止相对电导率的上升,减少发病率。对膜结构变化与虎皮病的关系进行了讨论。     

刍议动物防疫行政执法鉴定结论的合法性

动物防疫行政执法的鉴定行为是指动物防疫行政执法过程中执法机关及其执法人员对管理相对人所经营的动物及动物产品、运输工具、经营场所等的合法性予以评定的活动,通过一定的程序和方法得出足以说明管理相对人的经营行为是否合法的结论,此结论亦可称为动物     

Experimental infection of pregnant gilts with swine hepatitis E virus

To determine the effect of swine hepatitis E virus (HEV) infection on pregnant gilts, their fetuses, and offspring, 12 gilts were intravenously inoculated with swine HEV. Six gilts, who were not inoculated, served as controls. All inoculated gilts became actively infected and shed HEV in feces, but vertical transmission was not detected in the fetuses. There was no evidence of clinical disease in the gilts or their offspring. Mild multifocal lymphohistiocytic hepatitis was observed in 4 of 12 inoculated gilts. There was no significant effect of swine HEV on fetal size, fetal viability, or offspring birth weight or weight gain. The offspring acquired anti-HEV colostral antibodies but remained seronegative after the antibodies waned by 71 days of age. Swine HEV infection induced subclinical hepatitis in pregnant gilts, but had no effect on the gilts' reproductive performance, or the fetuses or offspring. Fulminant hepatitis associated with HEV infection was not reproduced in gilts.     

Expression of β2-integrin on monocytes and blood polymorphonuclear leukocytes in the periparturient period in dairy cows

The hypothesis that an altered expression of CD11/CD18 on bovine circulating monocytes, polymorphonuclear leukocytes (PMN), or both, contributes to an increased mastitis susceptibility in periparturient cows was tested. Expression of CD18 and CD11a, -b, -c on bovine monocytes and PMN were assessed in 8 Friesian-Holstein cows by flow cytometry from 2 wk before calving to 5 wk after calving. Minor changes in adhesion molecule expression levels were detected throughout the experimental period. Compared with PMN, monocytes exhibited an expression level that was similar for CD18, higher for CD11a and CD11c, but lower for CD11b. Differences in density may reflect the relative importance of these adhesion molecules on both leukocyte types. In this study, the decreased number of milk resident macrophages and PMN observed during the periparturient period could not be attributed to changes of CD11/CD18 levels on circulating leukocytes.     

Spatial structures of copper,lead, and mercury contents in surface soil in the Shenzhen area

Eighty-three surface soil samples were collected from the Shenzhen area for determination of copper, lead, and mercury contents. The nature of spatial dependence of the measured results was quantified using variogram analysis. All variograms show well-defined structure with zero nugget and distinct sills and ranges and can be fitted by a spherical model. The range scale and the geometric anisotropy of the variograms suggest that the spatial structures of copper and lead relate closely to the distribution of parent material in the area. The variogram of mercury appears to be isotropic with a relatively small range, indicating significant influence of geographical distribution of paddy soil fields that have been severely polluted by agricultural practice.     

茄子早熟育种研究Ⅱ选择指数与早熟性选择

研究结果表明,由性状果实最大周长,果实体积,门茄显蕾期,单株产量等性状构成的选择指数较好;进一步进行遗传相关分析结果认为,应用选择指数时应注意果实体积这个性状,单株产量是一个重要的辅助性状,门茄显蕾期是一个限制性因子。应用选择指数对品种评价结果认为,早熟性较好的品种有:天津早茄、西安绿茄、二民、七叶茄、白线茄和汉中荷包。