Microbiological oxidation of testosterone by Gibberella fujikuroi (NCIM).

Abstract

In the course of our investigation in finding the potentialities of various microorganisms in transforming organic compounds, particularly steroidal hormones, Gibberella fujikuroi has been used. Literature survey (1-4) revealed that not much work has so far been done on the transformation of steroids by this particular fungus. Transformation of some flavonoids have been reported by UDUPA et al. (5,6). This prompted us to use this fungus in bringing about transformations of both steroids and aromatic compounds. For the present investigation testosterone (Ia) was used as the substrate.The strain of G. fujikuroi NCIM 665 used for the present work was kindly supplied by the National Collection of Industrial Microorganisms, Division of Biochemistry, National Chemical Laboratory, Poona, India. Preparation of slant cultures for inoculum and fermentation procedure were essentially those of UDUPA et al. (6). The only modification made by us was that the fermentation was carried out in a shaker instead of by intermittent aeration. The fermentation was carried out in 500-ml conical flasks (20 such flasks were used) each containing 100 ml of modified Czapek-Dox medium (7, 8) adjusted to pH 6.2. The flasks were sterilized at 15 P.S.I. for 15 min and inoculated with 6-day-old culture of G. fujikuroi grown on the slant culture of same compositions with agar (15 g/l). To each of the flasks, 10 mg (0.035 mM) of testosterone (in 1 ml acetone) was then added under sterile condition and the flasks were agitated in a rotary shaker (180 rpm) at 28°+ 1° for 20 days. The whole broth was then acidified with HCl (1: 1) and extracted with chloroform. This extract was found to contain two major steroidal compounds in addition to unreacted testosterone (in a very small amount) and other minor steroidal compounds (all Liebermann positive) as compared to the control. TLC was carried out on silica gel (Gouri Chemical Works, Calcutta), with a solvent system of benzene: chloroform: methanol 339

Production of outer membrane blebs during chlamydial replication

“…Furthermore, they are strikingly similar to the apperance of the outer membrane blebs produced by Gram-negative bacteria such as Neisseria meningitidis [2],N. gonorrhoeae [8] and Vibrio cholerae [3].…”

“…Chlamydia are obligate intracellular prokaryotic parasites which possess a cell envelope with a double unit membrane similar to that of Gram-negative bacteria [1 ]. Growth of free-living Gram-negative bacteria is frequently associated with release of blebs of outer membrane (free endotoxin) from the bacterial surface; thin sections of these blebs examined by electron microscopy appear as single-membrane vesicles which range from about 30 to 75 nm in diameter [2,3].…”

Lysine excretion by a mutant strain ofPseudomonas aeruginosa

“…With Corynebacterium glutamicum it is essential to add biotin to the culture to divert the metabolism to lysine since otherwise glutamate is excreted. Bacillus megaterium CIII9 excretes lysine when grown in a chemically defined medium containing low concentrations of sulphate [14]. The excretion of lysine by the homoserine dehydrogenase mutant of P. aeruginosa, without special growth conditions, may reflect a less complex regulatory system for the biosynthesis of the aspartate family of amino acids in the pseudomonads.…”