利用地径建立林木材积估测模型的探讨

通过实测铁杉、红桦和湖北花楸的地径、胸径、树高和材积，我们建立了根据林木地径估测树木材积的数学模型，具有较高的相关系数，可以应用于森林资源管理和森林生态系统研究。     

Genomic and Pathogenic Studies on a Glycoprotein E Variant Field Isolate of Bovine Herpesvirus 1

Glycoprotein E-negative (gE–) laboratory strains of bovine herpesvirus 1 (BHV-1) were recently introduced as novel marker vaccines, allowing serological discrimination between vaccinated and naturally infected animals on the basis of lack or presence of antibodies against gE epitopes. The applicability of this approach is based on the genetic stability of the gE. However, mutant field variants of BHV-1 with a variable response in anti-gE ELISA have been isolated. The molecular characterization of a gE variant field isolate (Salwa strain) is presented here. By comparing the gE nucleotide and amino acid sequences of the Salwa strain with those of the wild strain Jura, ten mutated bases were found in the gE strain of Salwa, six of which alter the amino acid sequence, leading to changes in five amino acids. Both strains caused respiratory disease in experimentally infected calves, but Salwa generated slightly milder signs. Both viruses were excreted in nasal and ocular discharges, and were reactivated by dexamethasone treatment. In conclusion, the rather close similarities observed in the gE gene structure and pathogenicity features of the gE mutant and of the wild strain of BHV-1 confirm the genetic stability of gE. The findings indicate that the Salwa isolate is virulent, but less virulent than wild strains. Our data support the use of gE-negative marker vaccines in eradication programmes.     

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为了解新疆南疆地区犬戊型肝炎病毒(HEV)感染的情况及流行特点,为其科学防控提供参考依据,采用酶联免疫吸附试验法,对新疆南疆地区采集的160份犬血清进行HEV IgG抗体检测,并比较不同来源、品种、年龄及性别犬HEV IgG抗体的阳性率差异.结果表明:160份被检血清中有21份HEVIgG抗体呈阳性,阳性率为13.13％.其中,农村饲养犬的阳性率为25.46％(14/55),城市家养犬为6.67％(7/105),差异极显著(P＜0.01);5岁以上、2～5岁和2岁以下犬的抗体阳性率分别为10.71％、16.84％和5.41％,差异显著(P＜0.05);贵宾犬、金毛猎犬、京巴犬、牧羊犬和其他品种犬的抗体阳性率分别为25.71％、6.52％、7.90％、0％和18.18％,金毛猎犬和金巴犬间差异不显著(P＞0.05),其他各品种间差异极显著(P＜0.01);雄性犬和雌性犬的抗体阳性率分别为19.77％和5.41％,差异极显著(P＜0.01).新疆南疆地区犬已受到HEV感染,应加强人犬之间的公共卫生防护.     

家蚕品种最适环境片区的划分

对家蚕品种最适环境片区划分进行了研究,初步得到如下结果：参试的8个地区可以划分为两个环境片区。第一个环境片区包括四川、重庆和浙江;第二个环境片区包括陕西、山东、安徽、湖北和镇江;第一个环境片区的最适基因型是品种B;第二个环境片区的最适基因型是品种C。如果在各环境片区推广相应最适基因型比在所有地区只推广品种C,则全区平均万蚕收茧量可提高2．1％。     

Vaccination experiments on pregnant mice with E. coli vaccines prepared from septicaemic and enteropathogenic strains of E. coli

Experiments have been carried out with vaccination of pregnant mice against E. coli, followed by i.p. challenge of the offspring at one week of age.With a septicaemic strain the results were highly significant, and the method is therefore recommendable for testing of vaccines against such strains of E. coli.Results were less clear-cut with enteropathogenic strains of E. coli. However, with mortality rates of 40 to 45 % in baby mice born by non-vaccinated mothers and less than 15 % in baby mice born by vaccinated mothers, the difference in percentage mortality seems sufficient to warrant the use of the method also in the control of vaccines against enteropathogenic E. coli strains.     

细胞钙超载与鸡柔嫩艾美耳球虫病损伤关系

为探讨鸡柔嫩艾美耳球虫（E．tenella）宿主细胞损伤与钙超载的关系，采用组织定量检测、Von Kossa钙染色、焦锑酸钾电镜细胞化学技术对使用和未使用钙离子阻断剂的E．tenella感染鸡盲肠组织的细胞沉积钙、ATP酶、磷脂酶A2（PLA2）、游离脂肪酸和盲肠上皮细胞游离Ca^2＋的含量与分布进行了动态测定和分析。结果表明：（1）鸡患柔嫩艾美耳球虫病过程中，宿主细胞内钙和游离Ca^2＋明显增多（P〈0．01），并随盲肠损伤加重而增加；（2）在发病过程中盲肠组织Na^＋-K^＋-ATP酶、Ca^2＋-Mg^2＋-ATP酶、总ATP酶活性均有不同程度的下降，在感染严重期显著低于不感染对照组（P〈0．01）；（3）钙超载盲肠组织的PLA2活性和游离脂肪酸含量明显升高（P〈0．01），表明钙超载是鸡柔嫩艾美耳球虫病的一个重要损伤机制；（4）硝苯地平可以阻止Ca^2＋内流，减少宿主细胞内游离Ca^2＋，减轻宿主细胞的损伤，在本病发生的早期盲肠损伤较轻时，对鸡有一定的保护力，但随着疾病的发展，其作用下降。     

Capacity of selected Illinois soils to remove lead from aqueous solution

Abstract

Lead is being added to the environment in automotive exhausts and as an industrial pollutant. To understand its fate in the environment, it is necessary that factors affecting the capacity of soils to sorb Fb be determined.

The capacity of soils to sorb Fb from aqueous solutions vas measured for selected Illinois soils via column leaching experiments and adsorption isotherms. A regression equation was determined that predicted the capacity of a soil to sorb Fb based on its C.E.C., pH and soluble F level. Results of the regression analysis indicated that soil properties associated with increasing C.E.C., i.e. higher organic matter content, higher surface area, and higher clay content have a greater effect on Fb sorption than soil pH, and that soil pH has a greater effect than soluble P.     

彩色茧（金黄色）新品种金秋×初日永康试养初报

家蚕新品种金秋×初日除具有天然金黄色蚕茧性状外,其它各项经济性状与对照种秋丰×白玉相仿。但在气候比较恶劣的环境下,金秋×初日明显的表现出强健性高,发病率低,是一对能适合适度规模化省力化饲养,特别是在饲养条件比较差的环境下取得稳产的优良品种。