Effect of culture media and environmental factors on mycelial growth and pycnidial production of Lasiodiplodia theobromae in physic nut (Jatropha curcas ).

Physic nut (Jatropha curcas) is an important commercial bio-diesel plant species and is being advocated for development of waste and dry land. The collar and root rot caused by Lasiodiplodia theobromae is an important soil borne disease which causes considerable yield loss in this crop. In this study, the effects of culture media, temperature, photoperiod, carbon and nitrogen sources and pH on mycelial growth and pycnidial production were evaluated. Among the growth media tested, potato dextrose agar supported the highest growth followed by potato sucrose agar and corn meal agar. Among several carbon sources tested, carboxy methyl cellulose and sucrose were found superior for growth and pycnidial production. The nitrogen sources viz., ammonium oxalate and ammonium dihydrogen phosphate were recorded maximum mycelial growth and pycnidial production. The fungus grows at pH 5.0-9.0 and optimum growth was observed at pH 7.0.

Development and characterization of monoclonal antibodies to foot and mouth disease virus type 'C'.

Five fusion experiments were conducted with spleen cells from Balb/c mice immunized with purified 146S antigen of foot and mouth disease virus type 'C' (vaccine strain). Monoclones (31) thus developed were isotyped as IgM (3), IgG1 (6), IgG2a (5), IgG2b (3) and IgG3 (14). Eleven clones isotyped as IgM, IgG2a and IgG2b showed neutralizing activity in virus neutralization and plaque reduction tests. Six of the neutralizing clones precipitated 146S virus in Ouchterlony reaction. On the basis of location of MAb reactive epitopes in relation to intact virus (146S), 12S particles and VP1 in ELISA test, the clones were classified as Class II (6), Class III (11) and Class IV (14). These clones may be useful for purposes of antigen detection from field isolates and for estimation of antibody titres in vaccinated animals.

Nucleotide sequence of DR-B exon of major histocompatibility complex from an Indian zebu cattle breed.

The Indian cattle is known to be more tolerant to tropical infections than the European cattle. In order to verify the genetic basis of this variation, the DR B exon-2 of the major histocompatibility locus, known for coding the antigen recognition site, from the Hallikar breed of Indian cattle was amplified by PCR, cloned and sequenced. Comparison of this sequence with the information available on taurus cattle brought out six unique nucleotide changes and three amino acid changes. The amino acid positions were at 17, 72 and 87. A major variable region was observed at amino acid position 85 to 87 from all the alleles so far reported for the bovine locus.

Direct detection of bovine herpes virus-1 DNA from cell culture fluids using polymerase chain reaction.

A pair of oligomers of 20 and 23 bp were designed for amplifying a 381 bp sequence from glycoprotein IV gene of bovine herpesvirus 1. The primer pairs were used for amplifying genomic DNA of BHV-1 directly from cell culture fluids under different experimental conditions such as, untreated cell culture fluid, thermal denaturation and proteinase K treatment in presence of detergent. The results reveal that direct thermal denaturation of cell culture fluid is sufficient to detect the virus by polymerase chain reaction.