Biological control of the tick fowl Argas persicargas persicus by the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae

The pathogenicity of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae against the tick fowl Argas persicargas persicus was studied. Bioassays revealed significant differences between the two fungi and the A. persicargas persicus stages exposed. The first nymphal instar was more highly susceptible to both fungi than the second nymphal instar. The unfed female of A. persicargas persicus was significantly less susceptible to both fungi than the engorged female. Application of M. anisopliae to sackcloth naturally infested with the tick fowl A. persicargas persicus induced mortality which reached 100?% three weeks after treatment under field conditions. The present study suggests that entomopathogenic fungi have good potential for tick fowl, A. persicargas persicus, control.     

Virulence factors in Escherichia coli isolated from the blood of bacteremic neonatal calves

Twenty-five Escherichia coli isolates from the blood of critically ill bacteremic calves sampled in two separate studies on a calf-rearing farm housing over 15,000 calves, in the San Joaquin Valley, California were studied.Isolates were characterized for O serogroups and for pathotypes as determined by the presence of specific virulence factors including heat-labile enterotoxin (LT), heat-stable enterotoxins a and b (STa, STb), verotoxins 1 and 2 (VT1, VT2), cytotoxic necrotizing factor (CNF), aerobactin, intimin Eae and P, F17 and CS31A fimbrial adhesins, and resistance to bactericidal effects of serum.These isolates constituted a heterogeneous group. However, isolates were mostly aerobactin positive and often resistant to the bactericidal effects of serum. Isolates of pathotypes O78 (n=6), O119:CS31a (n=3), and P positive but O non-typeable (n=3) were associated with a high mortality rate. The remaining isolates belonged to diverse pathotypes, often possessing the adhesins P, F17, CS31A and Eae but belonging to O serogroups other than O78 and O119, and were less frequently associated with mortality.Although no virulence factor common to all isolates was identified, the capacity to use iron by the presence of aerobactin which is important to the capture of iron was a predominant factor. Moreover, certain pathotypes appear to be associated with primary colisepticemia whereas other pathotypes may cause a bacteremia without necessarily leading to septicemia.     

DNA methylation status in tissues of sheep clones

Genomic imprinting and DNA methylation play an important role in mammalian development. Many cloned animals showed heterogeneous DNA methylation profiles. However, there are fewer reports in cloned lambs because of a lack of genomic imprinting information. In this study, we investigated DNA methylation patterns in CpG islands and differentially methylated regions of putative imprinted gene Peg10 and imprinted genes Dlk1, Igf2R and H19 in cloned lambs. Five organs from two cloned lambs died shortly after birth and two normal controls were investigated. We observed normal DNA methylation profiles in cloned lambs. The imprinted genes Dlk1, Igf2R and H19 in livers, kidneys, hearts, muscles and lungs of the two cloned lambs exhibited relatively normal DNA methylation, except for Peg10 showing some differences between controls and cloned lambs. Our results indicate that somatic cell nuclear transfer-produced sheep exhibited relatively normal DNA methylation pattern and experienced normal DNA methylation reprogramming at imprinted loci.     

Response of greenhouse cucumber to mineral fertilizers on a high phosphorus and potassium soil

The response of greenhouse cucumber (Cucumis sativus L. cv. Lolita) to nitrogen (N), phosphorus (P) and potassium (K) fertilizers on a soil high in available P and K was studied during 1986. The greenhouses were located in the Beqa Valley, central Lebanon, and their soil chemical properties before planting were: NO₃‐N = 52 ppm, P(NaHCO₃ ext.) = 100 ppm, K (ammonium acetate ext.) = 650 ppm, ECe = 1.6 dS/m, pH = 7.5. Nitrogen at 200 kg/ha, P at 85 kg/ha and K at 150 kg/ha were applied in the following combinations: N, N+K, N+P+K and an unfertilized control. The rates were split into four equal weekly applications starting on the fourth week after transplanting the seedlings to the greenhouse. The treatments were applied through the drip irrigation system of the greenhouses. Fruit yield over the two months of harvest was highest in plants receiving N alone, which yielded 57 ton/ha. Yields of the plots receiving N+K, N+P+K and the control were 55.0, 54.0 and 39.5 ton/ha, respectively. Yield during the first month of harvest was comparable in all fertilized treatments and was substantially higher than the control.