Polychlorinated biphenyl contamination of areas surrounding two transformer salvage companies, Colman, South Dakota--September 1977

Soil, corn plants, and foliage from areas surrounding two electrical salvage companies involved in reconditioning old transformers had unusually high levels of polychlorinated biphenyls (PCBs). Levels decreased as distance from the factories increased. PCBs were dispersed into the air through incineration of waste oils; water and soil contamination was caused by runoff from the factories. PCBs found in the contaminated areas closely resembled Aroclor 1260 as did the PCBs in the waste oil, whereas PCBs in other areas were more similar to Aroclor 1254. PCBs on surface soils taken from an unplowed pasture near the factories also resembled Aroclor 1260, whereas samples taken from depths of 2-4 inches showed degradation of some PCB isomers. PCB concentrations in corn cobs and kernels were < 0.05 ppm, whereas leaves contained PCB levels of up to 2.2 ppm. PCB levels in earthworms and small rodents collected near the factories were considerably higher than levels in the same types of animals collected from other areas.     

Bovine antibody against Streptococcus agalactiae, type Ia, produced by preparturient intramammary and systemic vaccination.

Four pregnant heifers were immunized by the intramammary route with killed or live Streptococcus agalactiae vaccine, and a 5th heifer was vaccinated by the intramuscular route with killed vaccine. Antibody in the colostrum from vaccinated and non-vaccinated glands was compared. Antibacterial glands was compared. Antibacterial antibody titers of the 4 immunoglobulin classes were determined by indirect fluorescent antibody assay. Although the content of immunoglobulin G1 (IgG1), IgG2, and IgM in the colostrum from the vaccinated glands was not substantially different from the nonvaccinated glands, IgA content was considerably greater in the former. Antibody specific to S agalactiae was isolated from all colostrum samples. The mouse passive protection test and Ouchterlony analysis were used to demonstrate the presence of type-specific antibody to Ia strain used for vaccination. The passive mouse protection test also was useful to compare the protective capacity of specific S agalactiae, type Ia, antibodies of immunoglobulin classes IgG, IgM, and IgA. Increased protective capacity of IgM and IgA over IgG1, on a weight basis, was demonstrated. The present study indicates that S agalactiae preparations, when introduced into the mammary gland, can give rise to local antibody synthesis in the vaccinated glands.     

The in vivo sensitivity of ATPases to DDT,DDE, and physical immobilization in American cockroaches

American cockroaches injected with sublethal doses of DDT (0.75 μg/roach) at 5-day intervals showed a 40% reduction in oligomycin-sensitive Mg²⁺ATPase from muscle homogenates, and a 23% reduction of Na⁺-K⁺ATPase from nerve cords. Thus, the maximum effect measured occurred with the same enzyme and tissue as determined from in vitro studies. The metabolite, DDE, used at 15 μg per roach, gave no significant change in activity of the ATPase system following injection. In contrast, high single doses of DDT (7.5 μg/roach) and 100 μg DDE and dicofol per roach caused over 30% increase in oligomycin-sensitive Mg²⁺ATPase of muscle and a 10–15% increase in Na⁺-K⁺ATPase of nerve cords measured 24 and 48 hr later. While a similar response was observed for Mg²⁺ATPase activities in cockroaches that were immobilized, the increase in enzyme activities were much greater than that caused by the pesticides.     

Differential tolerance of peas to prometryne and terbutryn

The phytotoxicity of 2,4-bis(isopropyl)-6-(methylthio)-s-triazine (prometryne) and 2-(tert-butylamino)-4-(ethylamino)-6-(methylthio)-s-triazine (terbutryn) to peas (Pisum sativum L. var. Perfection 3040) was studied. No differences were found when the herbicides were applied to the roots of intact plants in nutrient solution or directly to leaf discs. However, prometryne was much more toxic when uptake was from soil. Absorption and translocation of ¹⁴C-labeled prometryne and terbutryn showed that the majority of terbutryn accumulated in the roots, whereas prometryne was uniformly distributed between the roots and the shoot. Thin layer chromatography of extracts from prometryne-treated peas showed that only 20% of the absorbed compound was metabolized to produce one breakdown product. Extracts of terbutryn-treated plants contained three different metabolites. After 120 hr of exposure to terbutryn, about half of the absorbed herbicide was metabolized. The results show that the main factors responsible for the differential toxicity of the herbicides to peas were availability from the soil, translocation pattern and initial detoxication.     

Effect of infections with barley yellow dwarf virus and Fusarium spp. on assimilation of 14CO2 by flag leaves and translocation of photosynthates in wheat

Journal of Plant Diseases and Protection - The effects of infections of Barley yellow dwarf virus (BYDV), Fusarium culmorum and F. graminearum alone as well as double infections of BYDV and...     

Effects of sub-minimum inhibitory concentration antibiotic levels and temperature on growth kinetics and outer membrane protein expression in Mannheimia haemolytica and Haemophilus somnus

The objective of this study was to determine the effects of sub-minimum inhibitory concentrations (sub-MICs) of 2 veterinary antibiotic preparations, chlortetracycline (CTC) and chlortetracycline-sulfamethazine (CTC + SMZ), on growth kinetics and outer membrane protein expression in Mannheimia haemolytica and Haemophilus somnus at normal and febrile body temperatures. Sub-minimum inhibitory concentrations of both antibiotics reduced the growth rates of M. haemolytica and H. somnus. Growth of both species was not inhibited when grown at 41 degrees C compared to 37 degrees C. There was no detectable consistent effect of antibiotic or temperature on outer membrane protein expression for either species. Our study indicates that sub-MIC levels of CTC and CTC + SMZ markedly impair growth of clinical M. haemolytica and H. somnus isolates, potentially allowing more effective host clearance during infection.     

不同能量水平日粮对肉仔鸡生长及屠宰性能指标的影响研究

选择3周龄健康、无病、体重无显著差异的肉仔鸡96只,随机分为3组,每组设4 个重复,每个重复8只。分别饲喂蛋白质水平(19．5％)相同而能量水平不同(3．0 Mcal／kg、 3．08 Mcal／kg、3．16Mcal／kg)的3种饲粮。试验结果表明:前两周饲料转化(采食／增重)均以 中能量组(3．08 Mcal／kg)最好,为1．4416±0．1199,但三种不同能量水平对肉仔鸡平均日增 重、平均日耗料、饲料转化率均差异不显著(P>0．05);后两周饲料转化仍以中能量组最好,为 1．6362±0．1346,且显著优于高能量组(P<0．05),而与低能组和中能组之间差异不显著,各 能量处理组蛋白质、粗纤维、钙的代谢率均差异不显著(P>0．05),而磷的代谢率却存在显著 差异(P<0．05),其中,以中等能量组的磷代谢率最高,平均为90．73％;3种能量水平下肉仔鸡 半净膛率、全净膛率均差异不显著(P>0．05),表明能量水平并不影响肉仔鸡屠宰性能。