无特定病原体京白鸡的核型研究

采用腹腔注射秋水仙素,取骨髓细胞制备染色体标本,对无特定病原体京白鸡的核型进行了分析.并根据前10对染色体相对长度、臂比值及着丝点指数的测量结果,与已公布的其它地方鸡品种进行了比较.     

我国牦牛染色体研究现状

综述了近10年来我国牦牛染色体研究的情况,认为牦牛与普通牛在部分常染色体和Y染色体结构上的差异是导致犏牛雄性不育的原因之一,并指出我国牦牛染色体的研究,今后应以染色体带型标准化,染色体带型与经济性状的相关性,牦牛与其它牛种染色体的比较研究等为主攻方向。     

动物细胞遗传学研究现状及其应用

本文介绍了细胞遗传学在动物方面的研究现状及其在畜牧业上的应用。细胞遗传学的研究主要以染色体为对象。目前世界上现存的哺乳动物约4100多种,其中进行过染色体研究或核型分析的有1468种,我国已研究过的有242种。细胞遗传学在人类医学上的应用是众所周知的,在畜牧业上主要用于对种畜进行细胞学检查,以消除对家畜繁殖性能有影响的畸变染色本,以染色体标记来识别家畜品种,对环境污染的监测及遗传操作中的染色体工程。     

Epidemiological studies of piglet diarrhoea in intensively managed Danish sow herds. II. Post-weaning diarrhoea

This study comprised 48,931 litters in 89 sow herds. During the study (1976-82) weaning age decreased from approx. 42 days to approx. 30 days. The mean incidence of post-weaning diarrhoea was 6.0% of litters weaned, with little variation by year but with considerable variation among herds. Within the individual herd increased incidence occurred over limited periods, probably associated with specific infections. Litters with diarrhoea during the suckling period had increased risk of post-weaning diarrhoea. The incidence of post-weaning diarrhoea increased with litter size at weaning. Thus, a litter of 11-12 piglets at weaning had 1.2 times higher risk than litters with 8-10 piglets. In contrast to pre-weaning diarrhoea, there was no association between parity of the sow and diarrhoea in the litter after weaning. Litters weaned below 2 weeks of age had a 2-fold risk of developing diarrhoea after weaning and a 2.4-fold higher mortality rate than did litters weaned at 6-7 weeks. Similarly, litters weaned at an individual piglet weight below 3 kg bodyweight had a 3-fold higher risk of developing diarrhoea after weaning and a 5-fold higher mortality rate than did pigs from litters weaned at a bodyweight of 7-8 kg. The incidence of post-weaning diarrhoea decreased with increasing herd size. Piglets from litters with post-weaning diarrhoea had reduced weight gains after weaning and were 2.3 days older at 25 kg bodyweight than piglets from non-diarrhoeic litters. Likewise, diarrhoea after weaning was associated with an increased incidence of diseases of the skin and respiratory tract. Thus the risk of contracting respiratory disease was 4 times greater in diarrhoeic litters.     

N-甲基-D-天冬氨酸对肥育猪生长及激素水平的影响

选取体重51 kg左右杜长大肥育猪84头,随机分为2组,每组设3个重复,2组分别饲喂添加0、50 mg/kg N-甲基-D-天冬氨酸(NMDA)的饲粮,试猪体重达88 kg时结束饲养试验,并对猪生长性能及血液相关激素指标进行分析,结果表明50 mg/kg NMDA可以显著影响猪的生长性能及内分泌水平,试猪日增重提高9.31%(P＜0.01),料重比降低7.16%(P＜0.02);血清生长激素含量提高了92.54%(P＜0.01),IGF-I水平增加了50.68%(P＜0.05),TSH、FT 3、FT 4的浓度分别提高了78.40%(P＜0.02)、123.33%(P＜0.01)和60.58%(P＜0.03),胰岛素水平提高了62.61%(P＜0.05).由此可见,NMDA可以显著影响猪的生长及血清相关激素水平.     

各隔离株旋毛虫感染性的研究

以旋毛虫国际标准种 :旋毛形线虫(Trichinella spiralis)和本地毛形线虫(Trichinella nativa )为对照 ,对黑龙江省猪、犬旋毛虫对大、小鼠和猪的感染性进行了比较研究。结果表明 :4个旋毛虫隔离株均对大鼠不易感 ,但相对犬旋毛虫和 T.nativa而言 ,猪旋毛虫和 T.spiralis对大鼠的感染性较高 (P <0 .0 1)。猪旋毛虫、 T.spiralis、犬旋毛虫、T.nativa在大鼠体内的繁殖力指数 (RCI)分别为 (35 .0 2± 8.37)、(32 .10± 7.77)和 (2 .90±1.71)、(2 .6 6± 2 .19)。 4个旋毛虫隔离株对小鼠和猪的感染性存在着明显差异 ,猪旋毛虫和T.spiralis对小鼠和猪的感染性较强 ,其在小鼠体内 RCI分别为 (137.4 1± 7.80 )和 (15 9.86±7.4 7) ,在猪体内的 RCI分别是 (385 .6 8±4 1.5 1)和 (30 0 .5 5± 12 .4 5 ) ;而犬旋毛虫和T.nativa对小鼠和猪的易感性差 ,其在小鼠体内 RCI分别是 (6 4.98± 5 .0 5 )和 (5 8.15±4 .6 9) ,在猪体内的 RCI分别为 (0 .0 6 4± 0 .0 31)和 (0 .0 33± 0 .0 33)。研究结果揭示 ,黑龙江省猪旋毛虫相当于旋毛形线虫 (Trichinellaspiralis) ,犬旋毛虫相当于本地毛形线虫(Trichinella nativa )     

A Comparison of Techniques for Preparing Somatic Chromosomes in Ribes Species

Ribes plants,like most of other fruit trees ,are characterized by their large number but small size of somatic chromosomes.In the light of these spccial characteristies,we have examined several factorial combinations of material,pretreatment,slide preparing method and stain to identify the most promising techique for studying the chromosomes and further analyzing the karyotypes and chromosome banding of Ribes plants.The resuts indicated that the combination of root tip with pretreatment of 2m molL^-1 8-hydroxyquinoline plus 0.05% colchicine or 0.3% balm for 3-5 hours at 14℃,pre-hypotonic treatment of 0.07mol L^-1 KCl for 30min,fixation in Carnoy‘s fluid,hydrolysis in 5% cellulase and 5% pectinase mixture for 4-5 hours at 25℃,post-hypotoic treatment in distilled water for half an hour and staining in Giemsa Could make the chromosome preparation superior to other treatment combinations.     

硼浓度对毛木耳菌丝生长的影响试验

试验通过不同浓度的Na2B4O7在改变PDA培养基及棉子壳一木屑培养基的试验,测定了其对毛木耳菌丝生长的影响。结果表明:在200mg／kg浓度下促进作用最为显著,而其浓度超过400 mg／kg时对菌丝有强烈的抑制作用。     

Correlation between hydrolytic enzyme activities measured in bean seedlings afterTrichoderma koningii treatment combined with pregermination and the protective effect againstPythium splendens

An experimental protocol consisting in the colonisation of pregerminated bean seeds dressed withTrichoderma sp. was used in order to study the mechanisms correlated with the protective effect againstPythium splendens. Seed dressed with TH-11 (T. koningii) for 24 h presented a higher protective effect and a higher level of seed colonisation as compared to those dressed with TH-13 (T. longibranchiatum). The levels of seed coat colonisation by TH-11 and TH-13 was shown to be correlated with the carboxymethylcellulase activity, as measured in the seed coats retreived from germinating dressed bean seeds. The seed coat colonisation was also associated with an increased activities of endo-1,3--glucanase and endochitinase measured in seed extracts, and an inhibitory effect of seed extracts onPythium sporangia germination. Pretreatment of TH-13-dressed seeds with a commercial cellulase improved all parameters mentioned above, thus suggesting a role of cellulase activity in the colonisation process and the linked protective effect. The possible role of hydrolytic enzymes in the protective effects is discussed.     

绿豆根尖染色体的G显带

用风油精法在绿豆根尖细胞染色体上显示出了Ｇ带,其带纹数目随染色体浓缩程度而变化,以早中期和早后期的Ｇ带较为清晰,同源染色体带纹的数目、大小和分布基本一致,本文还讨论了风油精在Ｇ带诱导中的作用机制。