Research on the schizont cell culture vaccine againstTheileria annulata infection in Xinjiang,China

Tropical Animal Health and Production - Theileria annulata infection (TAI) is one of the most serious diseases of cattle in Xinjiang Autonomous Region of Uigur Minority Nationality. It has been...     

Chemical control of soil-borne pathogens in tuff medium for strawberry cultivation

The phytopathogenic fungi Fusarium oxysporum f. sp. lycopersici and Rhizoctonia solani were completely eradicated after exposure for 30 min to a 0.4-0.5 % aqueous solution by weight of formaldehyde. With metham-sodium, higher concentrations or longer exposures were needed to obtain similar results. When tested in tuff (a granular plant growth medium of volcanic rock origin), the toxicity of formaldehyde was lower and that of metham-sodium was higher, compared with the corresponding toxicities in aqueous solutions. Both fungicides eradicated the two fungi, as well as Pythium myriotilum, when tested under practical conditions in vertical aluminium tubes filled with tuff. No detrimental effect could be observed on strawberry plants subsequently grown in these columns.     

Application of the California mastitis test in intramammary Streptococcus agalactiae and Staphylococcus aureus infections of camels (Camelus dromedarius) in Kenya

A study was conducted on 207 lactating camels in six herds in Kenya to evaluate the California mastitis test (CMT) for the detection of intramammary infections (IMIs) caused by Streptococcus agalactiae and Staphylococcus aureus and to investigate the prevalence of both the pathogens in the camel udder. IMI with S. agalactiae was found in 12% of all camels sampled. IMI with S. aureus was present in 11% of all camels sampled. The herd-level prevalence of IMI varied between 0 and 50% for S. agalactiae and between 0 and 13% for S. aureus. Longitudinal observations over 10–12 months confirmed persistent infections for both pathogens. Observations in one herd suggested that camel pox was a contributing factor in spreading and exacerbating S. agalactiae udder infections.The CMT had quarter-level sensitivities of 77 and 68% for S. agalactiae and S. aureus in camels, respectively. The CMT specificities were 91% for both the pathogens.     

Predisposing factors in enterotoxemias of camels (Camelus dromedarius) caused by Clostridium perfringens type A.

C. perfringens type A was isolated from different organs and intestines from breeding and racing camels which died from peracute and acute enterotoxemias in two separate outbreaks. Pathological changes in the digestive tract were mild in breeding camels, and severe in racing camels. A polyvalent clostridial antiserum of bovine origin given intravenously had a life-saving effect on breeding camels, but not on racing camels. In the two outbreaks, fifty percent of the breeding camels were suffering from an acute Trypanosoma evansi infection, and 25% of the racing camels had developed a salmonellosis. It is suggested that both infections played an important role as predisposing factors for the outbreak of C. perfringens enterotoxemias.     

Coating and impregnating with endrin protects field-sown douglas fir seed

Chemically treated and untreated Douglas fir seed was evaluated in the laboratory and at four locations on National Forests in Oregon and Washington. Seed was treated by coating with endrin or endrin-thiram and by impregnation with endrin. In the laboratory, germination was adversely affected by impregnation and by field exposure. Also, bioassays of treated seed showed no differences in consumption by deer mice among endrin treatments, but more seed was eaten after exposure in the field than before. Deer mice were the most common seed eaters found on all field study areas, and their numbers exceeded the level prescribed as a minimum requiring protection prior to seeding. Observations during and at the end of two growing seasons indicated that seedling production and stocking were much greater from endrin-treated than untreated seed, but there were no significant differences among the three endrin treatments. In addition, performance of treated and untreated seed differed by area, with best results at the two locations known for favourable climatic conditions.     

The joint action of insect growth regulators and insecticides on strains of Spodoptera littoralis Boisd. That are susceptible or resistant to aminocarb

An investigation was made of the action of the juvenile hormone analogues (JHAs) methoprene (ZR-515) and 3-[5-(4-ethylphenoxy)-3-methylpent-3-enyl]-2, 2-dimethyloxirane (R-20458), and the insecticides chlorpyrifos and methomyl, when applied, separately or in combination, to the late insect stages of susceptible (S) and aminocarb-resistant (R_m) strains of Spodoptera littoralis Boisd. Sixth-instar larvae of the R_m strain showed detectable levels of cross-resistance to chlorpyrifos, methomyl and R-20458. However, cross-resistance to methoprene was less pronounced in the R_m strain. Treatment of the same instar with the ED₅₀ of methoprene produced an appreciable level of sterility in the S strain, but this level decreased in the R_m strain. Similar treatment with R-20458 caused a lower level of sterility in the S strain and the R_m strain was less affected. In the S strain, the ED₂₅ of either chlorpyrifos or methomyl when applied simultaneously with the ED₂₅ of R-20458, produced an antagonistic effect and the R_m strain was more capable of resisting the joint action of these compounds. The treatment, ED₂₅ chlorpyrifos + ED₂₅ methoprene produced an additive effect on the S strain, while the R_m strain tolerated their combined action. Nevertheless, the treatment, ED₂₅ methomyl + ED₂₅ methoprene produced additive effects on both the S and R_m strains. The prepupae of the R_m strain tolerated the action of the insecticides methomyl and chlorpyrifos. A similar pattern of cross-resistance was also detected against the action of the two hormones at the ED₂₅ level, while at the ED₂₅ level, both the S and R_m strains were almost equally sensitive to the action of the two juvenoids. Chlorpyrifos-JHA combinations produced additive effects on prepupae of the S strain while the R_m strain completely resisted their joint action. Methomyl-JHA combinations produced high potentiation in the S strain, but the R_m strain remained insensitive to their joint action. Detectable levels of tolerance to the action of chlorpyrifos and methomyl at the ED₂₅ and ED₅₀ levels were indicated in 2-day-old pupae of the R_m strain. This was less evident in the case of JHAs, particularly methoprene, which was to some extent equally effective on both strains; the reproductive ability of the S and R_m strains was highly affected by this compound. The pupae of the R_m strains were equally as affected as those of the S strain by the combination ED₂₅ chlorpyrifos+ ED₂₅ R-20458. Nevertheless, the two strains showed antagonism to the action of chlorpyrifos with methoprene. A high level of potentiation was produced in the S strain to the combination of methomyl and R-20458 but the R_m strain was able to withstand their combined action. Of interest in this respect was the action of the combination of methomyl and methoprene, for which high levels of potentiation were detected in pupae of the S and R_m strains. This combination also Produced a high percentage of sterility in mated females of the R_m strain.     

Leptin inhibits hepatocyte growth factor-induced ductal morphogenesis of bovine mammary epithelial cells

We examined the effect of stroma-derived factors, hepatocyte growth factor (HGF) and leptin, on morphological differentiation of bovine mammary epithelial cells (BMEC) in collagen gel three-dimensional culture in vitro. BMEC treated with HGF, but not leptin, formed duct-like organoids. The formation of organoids by HGF was enhanced by treatment with a mixture of insulin, cortisol and prolactin, while BMEC treated with the mixture alone did not produce the organoid. In contrast, the formation of organoids by HGF was dose-dependently inhibited by simultaneous addition of leptin, regardless of the presence or absence of the hormone mixture. These results suggest that stroma-derived factors intricately regulate mammary epithelial morphogenesis.     

Chlorpyrifos induces cardiac dysfunction in rabbits

This study was carried out to evaluate the effects of organophosphate (OP) insecticide chlorpyrifos on cardiac morphology and function in rabbits using echocardiography. Twenty New Zealand male rabbits were divided equally into four groups. Rabbits were exposed to chlorpyrifos in drinking water at concentrations of 0, 125, 250 or 375 ppm for 90 days. The comparison among the groups indicated that 375 ppm chlorpyrifos resulted in significant decrease (p<0.05) in heart rate (HR), cardiac output (CO), left ventricular fractional shortening (FS), left ventricular ejection fraction (EF), percentage thickening of left ventricle posterior wall (PWT), and significant increase (p<0.05) in left atrial diameter (LA), left ventricular internal diameter in end diastole (LVIDD), left ventricular end diastolic (EDV) and end systolic volumes (ESV) compared to those of the control group. These results showed that chlorpyrifos induces cardiac dysfunction in rabbits.