A "dipstick" enzyme immunoassay for detection of antibody to Brucella abortus in cattle sera.

An enzyme immunoassay that utilizes antigen bound to a matrix which can be removed from the substrate to stop development is described. The assay which is performed in glass or plastic disposable tubes uses Gel-Bond film strips for attachment of antigen. The only equipment requirements are a rotary shaker and a spectrophotometer (optional). The antigen coated strips are passed through a series of tubes containing test serum, wash solution, antibody-enzyme conjugate, wash solution and substrate-chromogen taking about 45 minutes to perform. In testing sera with or without antibody to Brucella abortus a very high correlation existed between same day tests and tests performed over several days as well as with data on the same sera obtained by an enzyme immunoassay in a microtiter format.     

Influence of noncellulosic contents on nano scale refinement of waste jute fibers for reinforcement in polylactic acid films

In the present study, nanofibrils of cellulose are extracted from waste jute fibers using high energy planetary ball milling process in wet condition. The rate of refinement of untreated fibers having non-cellulosic contents was found slower than treated fibers due to strong holding of fiber bundles by non-cellulosic contents. At the end of three hours of wet milling, untreated fibers were refined to the size of 850 nm and treated fibers were refined to the size of 443 nm. In the subsequent stage, composite films of poly lactic acid (PLA) were prepared by solvent casting with 3 wt% loading of untreated jute nanofibrils, treated jute nanofibrils and microcrystalline cellulose. The influence of non-cellulosic contents on mechanical properties of PLA films are investigated based on results of tensile test, dynamic mechanical analysis and differential scanning calorimetry. The maximum improvement was observed in case of treated jute nanofibril/PLA composite film where initial modulus and tensile strength increased by 207.69 % and 168.67 %, respectively as compared to neat PLA film. These improvements are attributed to the increased interaction of treated jute nanofibrils with PLA matrix due to their higher precentage of cellulosic contents and mechanically activated surface.     

阿拉善双峰驼驼乳蛋白中氨基酸的含量及营养价值

对10峰阿拉善双峰驼第一次分娩后、泌乳时间90d时驼乳中的必需氨基酸含量及其营养价值进行了研究。结果表明,在泌乳90d时所挤驼乳蛋白中Thr,Val,Met,Ile,Leu,Phe和Lys必需氨基酸的含量分别为4.52,6.20,3.16,5.61,9.48,4.73,7.75g/100g。驼乳蛋白质中的必需氨基酸构成和FAO/WHO的推荐值十分相近,驼乳蛋白质对人体具有很高的营养价值。     

大麦杂种后代的赤霉病抗性变异及抗性与棱性的关系

本文用５个二棱大麦“抗性强×抗性中”组合的Ｆ_６集团和４个“二棱抗性弱×六棱抗性中”组合的１１３个Ｆ_７系统以及５０对二棱和六棱近等基因系，进行了大麦赤霉病的抗性鉴定及遗传分析，结果表明：大麦赤霉病抗性受具有累加效应的微效多基因系统的控制，其广义遗传力为０．６０；二棱系统的抗性比六棱系统强，但控制抗性的基因和棱型基因之间连锁的可能性很小。     

Detection of colonies of Anaplasma marginale in salivary glands of three Dermacentor spp infected as nymphs or adults

Salivary glands from males of 3 Dermacentor species (D andersoni, D variabilis and D occidentalis) that were infected with either the Virginia or Idaho isolate of Anaplasma marginale as nymphs or adults were examined for colonies of A marginale by use of light and electron microscopy. Prior to dissection of salivary glands, exposed ticks were held at 25 C for 15 to 18 days, followed by a 3-day incubation at 37 C. Ticks of 2 species transmitted A marginale to calves; the third tick species was confirmed infected by demonstration of typical colonies in tick gut cells, but transmission was not attempted; Colonies of A marginale were seen with light microscopy in salivary glands of all 3 species of ticks; they were located in acinar cells that contained simple granules. Colonies varied morphologically from small, compact ones to larger structures that contained distinct organisms and often were adjacent to the host cell nucleus. Electron microscopy confirmed that the colonies were rickettsial organisms. Morphologic features of A marginale varied and included reticulated forms, forms with electron-dense centers, and small particles; these various forms were similar to those described previously in midgut epithelial cells of ticks. We believe that the organism seen within tick salivary glands may replicate in the glands before its transmission to the vertebrate host.     

Epidemiologic aspects of bovine anaplasmosis in semiarid range conditions of south central Idaho

The prevalance of Anaplasma marginale-infected cows, as determined by use of the modified rapid card agglutination (MRCA) test, was measured during a 4-year period (1980-1983). The prevalence of A marginale-infected cows, defined as positive reactors on the MRCA test, remained constant (31%-37%). The apparent incidence of A marginale transmission to susceptible cows was approximately 7% from 1980 to 1981, 8% from 1981 to 1982, and no transmission from 1982 to 1983. The occasional MRCA-positive cow became negative on the MRCA test, and 1 cow was determined to be free of A marginale infection by subinoculation of 100 ml of the cow's blood into a susceptible, splenectomized calf. Dermacentor andersoni, a known vector of A marginale, was often found on the cattle and in their environment. However, A marginale was not transmitted to susceptible, splenectomized calves, using collected ticks. Of 56 calves born to MRCA-positive cows, 82% were MRCA-positive within the first 3 months of life. These calves converted to MRCA-negative status and were determined to be free of A marginale infection by subinoculation of their blood into susceptible, splenectomized calves, indicating the passive transfer of colostral antibodies.     

Haemolysis in gel test for detecting bovine antibodies to Brucella abortus lipopolysaccharide

Optimal reagent parameters for a haemolysis in gel test for detection of bovine anti-Brucella abortus antibody were established. Using an alkali-treated crude lipopolysaccharide antigen attached to J-negative bovine erythrocytes, 0.125 mg of antigen, 0.1 ml of erythrocytes and 0.4 ml of guinea pig complement were required to perform 15 tests with appropriate serum controls. The haemolysis in gel test and an IgM radioimmunoassay (RIA) procedure were compared for their ability to detect the onset of increased serum antibody levels and antibody levels in sera diluted to extinction. While the RIA was more sensitive in amount of antibody detected, the haemolysis in gel test was equally able to detect initiation of antibody synthesis.