THE OVIPOSITIONAL RESPONSE OF THE AUSTRALIAN SHEEP BLOWFLY, LUCILIA CUPRINA, TO FLEECE-ROT ODOURS

SUMMARY The ovipositional response of Lucilia cuprina flies to odours emanating from fleece-rot lesions of greasy wool in which Pseudomonas aeruginosa bacteria proliferated, was studied. Fractionation of the fleece-rot odours was carried out by bubbling the volatile components through hydrochloric acid and sodium hydroxide solutions to remove basic odours and acidic odours respectively. It was found that the acidic/neutral odours of fleecerot wool, when perfused into wet, greasy wool, stimulated L. cuprina to oviposit. On the other hand, the basic/neutral odours of fleece-rot wool were virtually unattractive to the gravid fly. Similarly, the acidic/neutral odours emanating from fleece-rot lesions of clean wool from which the non-fibre components, wax, suint and epithelial debris, had been removed by scouring, were found to be unattractive to the gravid fly in choice tests.     

多花黑麦草×苇状羊茅杂种后代的细胞学可育性和越夏性

二倍体和四倍体多花黑麦草×苇状羊茅杂种 F_1 花粉母细胞减数分裂染色体具有较高的配对水平,单价体少,二价体多。存在低频率的三价体、四价体和较低频率的五价体,表明多花黑麦草和苇状羊茅染色体之间存在同源或部分同源和异源苏会配对,F_1 正常花粉频率平均为0～18.2%,不同杂交组合甚至同一组合不同植株均有很大的差异。F_1 的回交结实率很低,平均为0.05粒种子/小穗,且易与多花黑麦草回交。杂种后代自交结实率与其亲本一样均很低。开放授粉结实率则随着世代的增加显著提高,F_1 代平均仪为0.4%,至第五代高达65.5%。杂种后代越夏性以 F_1为最强,平均达79.9%,介于双亲之间或与苇状羊茅相近,随着世代的增加越夏性则逐渐丧失。推测越夏性丧失与杂种后代群体过早或过多地丢失苇状羊茅染色体,减少了优良基因重组的机会有关。育性正常、越夏性较强的黑麦草型第四代选系“891”的获得,表明把苇状羊茅的越夏性部分地转移到多花黑麦草中是可行的。     

卫氏与斯氏并殖吸虫在实验动物体内分布的比较观察

目的 比较两种主要对人体致病的肺吸虫在实验动物肺内与肺外（胸、腹腔）的分布，为临床诊断及药物治疗提供参考。方法 粪检肺吸虫卵阴性的猫犬分别经口感染卫氏并殖吸虫（P．W）与斯氏并殖吸虫（P．S）囊蚴，饲养3个月后粪检肺吸虫卵阳性时对犬、猫进行解剖，观察与统计内肺外虫数。结果 猫犬解剖所获得P．W与P．S成虫均以左、右肺下叶寄生成虫数最多，猫、犬感染P．W后检获肺外期与左、右肺的童虫数均无显著性差异（P〉0．05）。猫感染P．S后所检获肺外期童虫数与左、右肺的童虫数有显著性差异（P〈0．05），而犬感染P．S所检获肺外期童虫数与左、右肺的童虫数有高度显著性差异（P〈0．01）。猫感染P．W与P．S囊蚴后虫体平均回收率为41．84％，39．85％；犬感染P．w与P．S囊蚴后虫体平均回收率分别为47．44％，24．57％。经统计学处理猫感染两种虫体回收率显著高于犬（P〈0．05）。结论 两种肺吸虫在实验动物犬、猫肺部的分布均以左、右肺下叶寄生成虫数最多，猫犬感染P．S所检获的肺外期童虫数与检获左、右肺内的童虫数分别为有显著性差异（P〈0．05）与高度显著性差异（P〈0．01），猫感染虫体的回收率明显高于犬。     

长芒草草地在封育条件下群落结构和生物量变化的研究

在宁夏南部大面积分布着以长芒草(Stipa bungeana)为建群种的干草地,是重要的草场资源。为了进一步探索封育对植物群落结构和生物量的影响,从1984～1986年,在云雾山草原自然保护区内选择了因放牧、鼠害危害较严重的长芒草草地进行了封育试验。经过3年封育,长芒草群落结构已发生了显著变化,地上生物量与地下生物量成正比亦大幅度提高,为合理利用草地,保护草地,增加草地土壤肥力,发展畜牧业提供科学依据。     

COMPARATIVE STUDY OF INDIUM-111 LEUKOCYTES AND NEPHROSONOGRAPHY FOR DETECTION OF EXPERIMENTAL PYELONEPHRITIS IN DOGS

Nephrosonography was compared to In-111 WBC for detection of experimentally induced pyelonephritis in 12 dogs. Nephrosonography was performed during the acute and chronic phase of pyelonephritis in all dogs. Sonographic abnormalities were found in all infected kidneys imaged early after infection. In the chronic phase of pyelonephritis, the sonographic abnormalities had decreased in severity in 9 kidneys, increased in severity in 2 kidneys, and had resolved in 2 kidneys. After histopathologic evaluation, eleven of fifteen kidneys (73%) with pyelonephritis had been identified by sonography. The In-111 WBC scan was performed during the acute phase of pyelonephritis in 9 dogs and during the chronic phase in all dogs. During the acute phase of pyelonephritis, the WBC scan was positive in 8 of the 9 dogs (89%) on images acquired 24 and 48 hr after injection of the labelled WBC. During the chronic phase of pyelonephritis, the WBC scan was negative in all 12 dogs. The sensitivity of the In-111 WBC scan was poor compared to nephrosonography for detection of chronic pyelonephritis. In this study, optimal detection of renal infection/pyelonephritis by In-111 WBC may be dependent on the presence of clinical signs and leukocytosis in dogs. Even when leukocytosis is present, the In-111 WBC may fail to accumulate in the kidney in dogs with pyelonephritis, particularly if no clinical signs (fever, depression, inappetence) are present.     

A COMPARATIVE STUDY OF EXPERIMENTAL ANAPLASMOSIS IN BOS INDICUS AND BOS TAURUS CATTLE

Comparative studies were carried out on the susceptibility of 8 Bos taurus and 10 predominantly Bos indicus cross cows aged 48 months to Anaplasma marginale infection. Measurements were carried out on bodyweight, parasitaemia, haematological factors, humoral antibody response and serum transaminase levels. Except for minor differences in reaction Bos indicus and Bos taurus animals were equally susceptible to infection with the strain of A. marginale employed. Such differences observed were not significant.     

THE ISOLATION OF MYCOPLASMA HYOSYNOVIAE AND EXPOSURE OF PIGS TO EXPERIMENTAL INFECTION

Arginine-utilising mycoplasmas isolated from the pneumonic lungs of 4 pigs were identified as M. hyosynoviae by their growth characteristics, biochemical activity and serological similarity to each other and to 2 type strains of M. hyosynoviae in growth inhibition tests. A purified culture of one M. hyosynoviae isolate was inoculated intravenously into 3 pigs which were killed 9 days later. Although arthritis was not observed clinically, M. hyosynoviae was isolated from 8 of 9 joints cultured, the tonsils and retropharyngeal lymph nodes of all 3 pigs and the lungs of 2 pigs. No histopathological changes were observed in synovial membranes of the joints cultured or lungs but severe depletion of lymphocytes in the cortex of lymphoid follicles in lymph nodes and tonsils was observed.     

THE SURVIVAL OF TAENIA PISIFORMIS EGGS UNDER LABORATORY CONDITIONS AND IN THE FIELD ENVIRONMENT

This study reports on the long-term survival of Taenia pisiformis eggs held under controlled laboratory conditions and in the external environment. Egg viability was assessed by feeding the ova to susceptible rabbits. In the laboratory experiment dried eggs were stored under 4 different temperature and relative humidity regimes. At various time intervals eggs were removed from these environments and fed to rabbits which were subsequently killed and the number of viable cysticerci within them counted. The results show that a high temperature (38 degrees C) and to a lesser extent, a low humidity (33%) are quickly lethal to eggs and few survive for more than 7 days. However, at 4 degrees C and a relative humidity of 90%, some eggs were still viable after 300 days. At the lower temperature there was a noticeable interaction between temperature and relative humidity. For the field study a small area of pasture was enclosed by a rabbit-proof fence and hessian screen. The pasture was first shown to be substantially free of extraneous contamination with T. pisiformis ova and was then artificially seeded with a large number of eggs. Fresh groups of susceptible rabbits were grazed on this pasture at intervals thereafter. The results, expressed as the mean number of cysticerci recovered from rabbits, show that eggs remain viable for several months during winter and early spring, but in summer no viable eggs could be demonstrated after a period of 2 weeks.     

抗菌肽基因导入桑树获得抗病转基因植株

用携带抗菌肽基因的农杆菌处理桑子叶,在含有羧苄青霉素（Cb）400～500mg／L和卡那霉素（Km）20mg／L的MS培养基上,有32.4％的子叶产生了不定芽;66.5％的不定芽在含有Cb300mg／L和Km30～40mg／L的培养基中,正常生长成2～3cm高的新稍;新梢在含Cb50mg／L和Km10mg／L的生根培养基中有72．6％形成完整根系。3次转化共获得12个株系55株KmR植株。不同株系桑苗叶片DNA点杂交分析显示,7个株系有阳性杂交信号。KmR株系桑苗的抗病性测定显示,5个株系共14株桑苗对青枯病具有较强抗性.     

西宁地区草坪建植当年秋季修剪对分蘖和越冬率的影响

2 0 0 0～ 2 0 0 1年对建植当年的混播草坪采用不同的停止修剪时期和修剪强度的试验。结果表明 :在8月底以前与这之后的停止修剪处理间越冬率差异显著 (p <0 .0 5 ) ,并随着修剪时间的延迟 ,越冬率降低 ;处理间秋季分蘖随着修剪的延续呈现为增加趋势 ( 1 7.6%～ 33.8% )但未达到显著水平 (p >0 .0 5 ) ;延迟修剪明显降低了春季分蘖率 (p <0 .0 5 )。秋季修剪间隔期的长短对越冬率、秋季分蘖亦存在明显影响。 1 0d间隔修剪处理 ,秋季分蘖明显增加 ,平均单株分蘖数达到 0 .74个 (p <0 .0 5 ) ,越冬率降至 2 2 .2 %。表明频繁修剪促进了秋季分蘖 ,但减少了主茎根和分蘖节中的物质积累 ,这是导致草坪越冬率降低的主要原因。因此 ,在西宁地区草坪建植当年秋季修剪应在 9月初停止 ,并适当延长秋季修剪间隔期。     

IMMUNITY TO EXPERIMENTAL STAPHYLOCOCCAL MASTITIS—COMPARISON OF LIVE AND KILLED VACCINES

SUMMARY Eleven pregnant Merino ewes were immunised with either a killed Staphylococcus aureus cell-toxoid vaccine (intramuscularly) or a living culture of the same organism (subcutaneously). A further 3 animals were used as non-immunised controls. There were no significant differences between the vaccinated groups for agglutinating antibody to staphylococci or for anti-α-haemolysin in either serum or whey. Three weeks after lambing the ewes were challenged by intramammary infusion of virulent staphylococci. All animals developed an acute mastitis with significant decreases in milk yields being recorded 48 hours post-challenge. Seven days after challenge the mean milk production of ewes given the live vaccine had recovered to within 5% of the pre-challenge mean yield. However, milk productions of controls and ewes given the killed vaccine had further decreased and were significantly lower than for animals vaccinated with live staphylococci. There were no significant differences between the two vaccinated groups for numbers of bacteria or leucocytes in milk samples collected after challenge. The ewes were killed 7 days postchallenge and mammary tissues were examined for immunoglobulin-containing cells. Large numbers of IgA-containing cells, and few IgM-containing cells were found, but there were no significant differences between the treatment groups for these parameters.     

农业保险发展的国际比较与启示

通过对欧盟、美国、日本等地区和国家农业保险发展的比较，总结了国外农业保险发展的共性和差异以及经验教训，期望能对我国农业保险试点和推广提供有益的借鉴和指导。     

家蚕病原性微孢子虫孢子表面蛋白的选择性分离与总蛋白比较分析

选择性分离了Ｎｏｓｅｍａｂｏｍｂｙｃｉｓ孢子表面蛋白和总蛋白，采用ＳＤＳ－ＰＡＧＥ检测发现，孢子表面蛋白由分子量不同的３种亚基（３２０００、２６０００、２４５００Ｄａ）组成，其总蛋白至少包括２５个条带。同时将从养蚕生产中收集到的两种微粒子ＭＡ－１和ＭＤ－１以及从野外昆虫收集到的微孢子虫Ｐｈａ－Ｍ和Ｈａ－Ｍ与Ｎ．ｂｏｍｂｙｃｉｓ进行了比较，发现不同微孢子虫间蛋白组成有差异。