Monoclonal-antibody-mediated enzyme-linked immunosorbent assay for detection of reticuloendotheliosis viruses

An enzyme-linked immunosorbent assay (ELISA) is described for the detection of reticuloendotheliosis viruses (REVs). The assay uses a mixture of monoclonal antibodies (MCAs) prepared against a 62-kilodalton REV envelope glycoprotein (gp62) to capture antigen, rabbit anti-REV serum as detection antibody, and peroxidase-conjugated anti-rabbit IgG as indicator antibody. The MCAs were reactive with REV strain T, chick syncytial virus, and duck infectious anemia virus but unreactive against Marek's disease and avian leukosis viruses. The ELISA was compared with complement fixation test and REV immunofluorescent assay of infected fibroblasts, plasmas, and egg albumen from infected chickens. The lower limit of gp62 detection was about 120 ng of REV protein. Limit dilution of infectious REV was detected after 7-8 days of cultivation of infected fibroblasts.     

In vitro testing of the anti-mycoplasma effect of some anti-coccidial drugs

The anti-mycoplasma effects of the ionophores (lasalocid sodium, monensin and nigericin) were compared with that of tylosin tartrate and tiamulin in vitro. Forty-four strains representing 14 avian and 10 mammalian Mycoplasma species and serotypes and 5 Acholeplasma species were tested. The ionophores showed average minimal inhibitory concentration (MIC) values between 3.65 and 4.93 micrograms ml-1 for all strains, the MIC values for glucose-fermenting strains were between 2.26 and 3.75 micrograms ml-1, significantly lower than for arginine-hydrolysing strains (9.27-13.12 micrograms ml-1). These values were significantly higher than those obtained with tylosin tartrate (0.45 micrograms ml-1) or tiamulin (0.13 micrograms ml-1). The ionophores were more efficacious against acholeplasmas (0.06-0.25 micrograms ml-1) than against mycoplasmas.     

Control of benomyl-resistant strains of Colletotrichum coffeanum, the cause of coffee berry disease

Sprays containing difolatan, dithianon, chlorothalonil and cuprous oxide were tested for the control of coffee berry disease (CBD) in 1979 and 1980 at an estate in Kenya with abundant benomyl-resistant strains of Colletotrichum coffeanum. In 1979 all fungicides gave good CBD control and increased yields of coffee. In 1980 only difolatan increased yield. Isolates of C. coffeanum capable of growing on agar with 8 μg/ml benomyl were detected throughout the 2 years of these trials.     

Plasminogen activator activity in secretions from clinically normal, mastitic, lactating and dried-off udders of dairy cows

Using the composite fibrin plates method, plasminogen activator (PA) activity was found in secretions from clinically normal, mastitic, lactating and dried-off udders of dairy cows. The possible involvement of the fibrinolytic system in the physiology and pathology of the bovine mammary gland is discussed.     

Effect of Some Weed Control Treatments on Sesame (Sesamum indicum L.) and Associated Weeds

Two field experiments were carried out during 1984 and 1985 seasons at the Farm of Shandaweel Agric. Res. Station, A. R. C, Ministry of Agric. (Egypt), to study the effect of five herbicides applied as a single or in tank mixtures as well as hoeing treatment on sesame plants and dominated annual weeds under Upper Egypt growing conditions. The herbicides alachlor at 2.304, pendimethalin at 2.040, linuron at 1.200, diuron at 0.960 and prometryn at 1.920 kg a.i./ha were applied preemergence as a single herbicides, as well as alachlor and pendimethalin combined with linuron, diuron or prometryn at the same rates. Two checks were included, one was left without weed removal, while the other was hand-hoed.
Pendimethalin at 2.040 applied alone or in mixtures with linuron at 1.200 or with diuron at 0.960 kg a.i./ha gave the best grass weed control, while excellent effectiveness against annual broad-leaves was obtained by linuron at 1,200 and diuron at 0.960 kg a.i./ha alone or in mixtures with pendimethalin at 2.040 kg a.i./ha. Whereas, pendimithalin at 2.040 applied alone or in tank mixtures with linuron at 1.200 or with diuron at 0.960 kg a.i./ha gave the best control for total annual weeds and higher seed yield of sesame as well as other yield contributing characters.     

水稻普通矮缩病毒致病力分化的初步探索

 水稻病毒病抗性育种工作在国外已进行了十余年,取得了显著成效,但对病毒致病力的分化问题却研究得不多。     

Immunoglobulins,haemolytic complement and serum C3 in cattle infected with malignant catarrhal fever herpesvirus

Serum levels of the third component of complement (C3) were reduced only in the terminal stages in malignant catarrhal fever (MCF) virus-infected steers. Haemolytic complement and immunoglobulin (IgM, IgG₁ and IgG₂) levels were not altered. C3 and immunoglobulin deposits were also not demonstrated in the vascular lesions induced by MCFV. MCF virus infection of cattle is probably not a typical immune complex-mediated disease as previously suggested.