Production of a biological control agent from Beauveria bassiana[Balsamo]Vuillemin fungus to fight against insect pests like the green peach aphid Myzus persicae[Sulzer]

This study presented as attempted to produce a biological control agent Beauveria bassiana [Balsoma] Vuillemin fungus against insects pests such as the green peach aphid Myzus persicae [Sulzer] the basic elements necessary for production of the bio-cidal agent were determined according to the recominded methods. The results showed that the best fermentation medium for growth of fungus B. bassiana, was consisted of two - extracts of potato and rice seeds, the concentration of fungal spores in volume unit [ml] was 27.0 x 10 8 spore/ml, while it was reduced to 22.0 x 10 8 spore/ml, and 21.8 x 10 7 spore/ml, in both media, potato extract and rice extract respectively. The efficiency of some substances such as [Kaoline, Rice seeds, Calcium carbonate and Talic] were tested as carrier substances to fungi. It was found that the Kaoline was appeared a better effective than the rice seeds with regard to the fungal concentration in weight unit [gm], reached to 17.0 x 10 7 spore/gm, while it was reduced to 10.0 x 10 6 spore/gm, in rice seeds substance, while two-substances Calcium carbonate and Talic were failed as substances carrying fungal inoculum. The percentage of [100] ml inoculum/[100] gm Kaoline was showed high significant results of the concentrations of fungal in weight unit [gm], reached to 17.5 x 10 7 spore/gm. The results of the laboratory and field - work evaluation referred to efficiency of the bio - cidal as follow:- 1- There is no change on the concentration of the fungal spores in weight unit [gm] of bio - cidal during the assigned storing period which lasted for six - months of storing reached to 17.0 x 10 7 spore/gm, in the first step of production and its continue to the end of storage period. 2. Whole concentrations of bio - cidal was appeared high efficiency on the average of mortalities of green peach aphid, Myzus persicae. 3- The bio - cidal was proved to have a high ability to use as a biological control against green peach aphid, in field experiment which was resulted in control against green peach aphid, in field experiment which was resulted in [80.31 percent] a mortality, when was compared with control treatment [0 percent]

Chemical modification studies of Rhizomucor miehei protease: evidence for the role of basic amino acids in enzyme catalysis.

The effect of chemical modification on milk clotting and proteolytic activities of aspartyl protease obtained from Rhizomucor miehei NRRL 3500 was examined in the absence and the presence of its specific inhibitor pepstatin A. The effect on the ratio of milk clotting activity (MC) to proteolytic activity (PA), an index of the quality of milk clotting proteases was also determined. Modification of the enzyme with trinitrobenzenesulfonic acid, diethylpyrocarbonate and phenylglyoxal produced an increase in the ratio of MC/PA, while modification with 2- hydroxy-5-nitrobenzyl bromide did not affect the ratio. Modification with N-acetylimidazole resulted in a marginal increase in MC/PA ratio. Protection using pepstatin A during modification with phenylglyoxal, N-acetylimidazole and 2-hydroxy-5-nitrobenzyl bromide, protected both MC and PA. In the case of modification by diethylpyrocarbonate, pepstatin A protected only MC. Pepstatin A did not protect both the activities on the modification of the enzyme by trinitrobenzene sulfonic acid. These observations indicate the presence of arginine, tyrosine and tryptophan at the catalytic site of the enzyme, for eliciting MC and PA of the enzyme. In general, modification of the positively charged residues increases the MC/PA ratio of the enzyme. In addition the modified lysine residues responsible for the inactivation of the enzyme were not involved in the active site of the enzyme. Thus the lysine residues might have a secondary role in enzyme catalysis. Further, histidine at the catalytic site was found to be exclusively involved in milk clotting activity. The enzyme with modified histidine residues were more susceptible to autocatalysis, indicating that histidine residues protect the enzyme against autolysis.