Microbiological transformations of steroids VI Amortization of 19-hydroxyandrosta-4,7-diene-3,17-dione into equilin

Washed mycelia and nongerminating spores of Fusarium solani aromatized 19-hydroxyandrosta-4, 7-diene-3, 17-dione into equilin and equilenin. The transformation was more complex with the mycelia rather than with the other unidentified products were formed early in the transformation. Substrate transforming enzymes appear to be induced in the mycelium and constitutive in the spores

Physiology and kinetics of a new L-Asparaginase from arthrobacter citreus

active intracellular L-asparagnase was detected in cultures of Arthrobacter citreus. The enzyme was farmed constitutively on a variety of media irrespective to the presence of the substrate or other structurally-related compounds. Glucose severely suppressed the enzyme formation The study of the physiology of formation has revealed that this enzyme reaches the maximum level at the end of the exponential phase and the beginning of stationary phase of growth followed by a rapid decline of the enzyme level upon further aging of the culture. The enzyme, obtained from the cells by benzene extraction. exhibited optimum activity at pH 3 and had an apparent KM 1.6 x l0-2M with respect to L- asparagire substrate. A significant substrate - protective effect was noted against heat iractivation of the enzyme at least up to 70§. The enzyme showed high specificity for L- asparagire and L- glutaminc with little or no activity on other amides tested. Significant activation was noted for magnesium ion whereas ferrous exhibited strong inhibitory effect. The properties of this enzyme are discussed in the light of possible application in cancer therapy

Microbial contamination of certain non-sterile pharmaceutical raw materials II: Contamination with bacteria of potential health hazard

A total of 119 pharmaceutical raw material samples from chemical, animal, plant, or other origin were examined for the presence of bacteria of potential health hazard. Of 71 batches of raw materials of chemical origin: 12, 2, 1, 5, 5, 6, 1, 4 and 2 batches were contaminated with Sraphylococeus aureus, Micrococcus pp., E. coil, Enterobacter spp., Citrobacter spp., Proteus spp., Salmonella spp., Shigello spp. and Ps. aeruginosa, respectively. Of 7 batches of raw materials of animal origin: 2 batches were contaminated with S. aureus, 2 batches were contaminated with Enterobacter spp. and one batch was contaminated with Citrobacter spp. Of ?2 batches of raw materials of plant origin: 3, 2, 1, l, 4, 1, 1 and 1 batches were contaminated with S. aureus, Micrococcus spp., E. coli, Enterobacter spp., Citrobacter spp., Shigella spp., Salmonella and Ps. aeruginosa,, respectively. Of nine batches of miscellaneous raw materials: one batch was contaminated with Micracoccus spp. and Proteus spp., one batch was conteaminated with Shigella spp. and Ps, aeruginosa: one batch was contaminated with S. eoielermidis, Citrobacter spp., and Ps. aeruginosa, one batch was contaminated with Micrococcus spp., Citrobacter spp., Proteus spp, and E. coli, and one batch was contaminated with S. aureus, Enterobacter spp., Citrobacter spp., Prote is sp. and Ps. aeruginosa. The remaining batches were not contaminated with any of the above mentioned objectionable microorganisms

Distribution and biosynthesis requirements for L-Asparaginase activities in bacteria and yeasts

Screening of 40 bacterial cultures, belonging to 16 genera and 24 yeasts, belonging to 10 genera, for levels of L-asparaginase activities was carried using a simple medium with L-asparagine asthe major carbon and nitrogen source. Among bacteria highestenzyme levels were noted for certain cultures of Erwinia, Arthrobacter and Serratia; whereas some species of Rlhodotorula, Debaryomyces and Schwanniomyces yielded the highest L-asparaginase activities among the yeast cultures tested. The use of cells stored frozen for a few days was necessary to obtain reliable information about the enzyme levels in the surveyed cultures. Physiological studies on selected cultures have revealed that the enzyme is inducible with L-asparagine and some structurally-related metabolites in Rhodvmruia rubra and Aerobacter aerogenes, whereas in several other cultures the enzyme is formed constitutively. Ammonium ion was a potent supressor of enzyme biosynthesis. Highest enzym levels were detected in cultures during the exponential and at the beginning of the stationary phases of growth whereas a wide variation in the enzyme stability was noted in different cultures upon extended incubation

Formation and properties of L-Glutaminase and L-Asparaginase activities in pichia polymorpha

An ascogenous yeast with high potentialities for L-glutaminase and L-asparaginase formation was isolated from Egyptian soils by the application of the method of enrichment culture. The organism, identified as pichia polymorpha, was obtained through the enrichment of the soil samples with a simple medium containing 0.5% L-glutamine as a major carbon and nitrogen source at low pH values. - The amidase activities were produced constitutively on a variety of media irrespective to the presence of their substrates in the growth medium. The assays of enzyme activity have revealed that optimum pH values for L-glutamine and L-asparagine hydrolysis are 6 and 6.7 respectively. The L-asparaginase activity of the cells were heat-stable at least up to 10 min at 600. The enzyme exhibited apparent km of 1.37 x 10[-2] M and 1.95 x 10[-2] M for L-asparagine and L-glutamine respectively. No metal requirements were detected for the amidase activities of the organism under study