Transformation of steroids by fungal spores: I. Chemical changes ofCunninghamella elegans spores and mycelium during cortexolone hydroxylation

Cyclodextrin Inclusion Complexes with Hydrocortisone-Type Corticosteroids

The hydrocortisone-type corticosteroid (HTC) group includes valuable active pharmaceutical ingredients (APIs) such as hydrocortisone, hydrocortisone acetate, cortisone acetate, tixocortol pivalate, prednisolone, methylprednisolone, and prednisone. Unfortunately, those APIs are characterized by low solubility, which hampers their application and reduces their therapeutic efficacy. The low polarity of HTC molecules allows them to form inclusion complexes with various cyclodextrins (CDs); however, as shown in this review, the type of applied CDs has a major impact on the final properties of the formed complex. HTC-CD complexes have been routinely used for over 40 years to achieve various aims. Most frequently, CDs have been utilized as HTC solubilizers and absorption enhancers in pharmaceutical formulations, as well as for separation and analysis by chromatographic and electrophoretic methods. This article reviews the studies describing the synthesis as well as the biological, physiochemical, and structural properties of the inclusion complexes formed between HTC and various cyclodextrins.

Exploring Morphological and Biochemical Linkages in Fungal Growth with Label-Free Light Sheet Microscopy and Raman Spectroscopy

Imaging tip growth in fungal hyphae is highly warranted to unravel the molecular mechanism of this extraordinarily precise and localized phenomenon. In situ probing of fungal cultures, however, have been challenging due to their inherent complexity and light penetration issues associated with conventional optical imaging. In this work, we report a label-free approach using a combination of light sheet microscopy and Raman spectroscopy to obtain concomitant morphological and biochemical information from the growing specimen. We show that the variance in morphology in the symbiotic fungus Piriformospora indica are rooted in the underlying differences in chemical composition in the specific growth zones. Our findings suggest that this potent two-pronged approach can comprehensively characterize growth areas and elucidate microbe interactions in still developing colonies with high sensitivity and multiplexing capability.

The influence of host-guest inclusion complex formation on the biotransformation of cortisone acetate Delta(1)-dehydrogenation

An intensive and systematic investigation had been carried out on the Delta(1)-dehydrogenation of cortisone acetate (CA) to prednisone acetate (PA) by Arthrobacter simplex TCCC 11037 in the presence of native and modified beta-cyclodextrins (beta-CDs). The biotransformation was improved through the formation of the host-guest inclusion complex between CA and CDs in aqueous solution. The inclusion complexes of CDs with CA were investigated by means of phase solubility, 2D NMR spectroscopy and differential scanning calorimetry (DSC). The structural difference of CDs resulted in the stoichiometric differences between the complexes, the RM-beta-CD-CA, SBE-beta-CD-CA, HP-beta-CD-CA complexes were 1:1 whereas beta-CD-CA gave both 1:1 and 2:1 complexes, of which the 2:1 complex decreased the soluble CA concentration and inhibited the dissociation of beta-CD-CA in aqueous solution. The increase in solubility of CA was in the order of RM-beta-CD>SBE-beta-CD>HP-beta-CD>beta-CD. RM-beta-CD-CA, SBE-beta-CD-CA and HP-beta-CD-CA exhibited the higher biotransformation rate in comparison with native beta-CD. And the solubilization of CDs for CA in aqueous medium plays a key role in the biotransformation process. The article focuses on the various factors influencing the substrate water solubility, complex stability and biotransformation of CA through the addition of CDs in order to solve many problems associated with the process of drug delivery and biotransformation of different novel steroids.

Elimination of by-products in 11β-hydroxylation of Substance S using Curvularia lunata clones regenerated from NTG-treated protoplasts

Stable mutants showing improved 11-hydroxylation of Substance S were isolated, following treatment with N-methyl-N'-nitro-N-nitrosoguanidine (NTG) and regeneration of uninucleate protoplasts of the appropriate fungal strains. This procedure was especially suitable for obtaining more directed 11 beta-hydroxylation of Substance S with Curvularia lunata IM 2901. Apart from producing cortisol (11 beta-hydroxy-S), the parent strain formed several by-products that significantly lowered the yield of the desired 11 beta-hydroxyderivative. Isolated mutants of this microorganism carried out directed 11 beta-hydroxylation with only a small amount of one of the by-products, which resulted in a much higher yield of cortisol.

Determination of cytochrome P-450 in Cunninghamella elegans intact protoplasts and cell-free preparations capable of steroid hydroxylation

Cytochrome P-450 was shown to be involved in 11 alpha-, and 11 beta-hydroxylation of Substance S in intact C. elegans protoplasts. The steroid transformation was inhibited by carbon monoxide, the inhibitory effect being dependent on CO concentration. The function of cyt P-450 in intact protoplasts was confirmed by the estimation of strong absorption at 450 nm in the CO difference spectrum. The presence of antimycin A was necessary to prevent the reduction of the cytochrome oxidase and its interference with the cyt P-450 in the spectrophotometric analysis. The intracellular content of cyt P-450 could be increased from 5.25 pM/mg protein to 26.88 pM/mg protein when the steroid inducer was present in the medium at each stage of protoplast preparation and during cyt P-450 determination. The enriched microsomal fraction obtained from the crude extract of ruptured protoplasts contained the steroid 11 alpha-hydroxylase system of C. elegans. The activity of 11 beta-hydroxylase could not be detected under the conditions of the experiment. The localization of steroid hydroxylases of C. elegans in microsomes was confirmed by cyt P-450 detection in the 9600 x g supernatant. Membranous fractions (pellets 1100 x g and 9600 x g) of the concanavaline A stabilized protoplasts, carrying the marker plasma-membrane-bound and mitochondrial ATPases, did not show maximum absorption at 450 nm in the CO difference spectrum.

Biotransformations of steroids

Different types of microbiological transformation of steroids are reviewed, with special attention given to bioconversions applied in the manufacturing of steroid hormones, i.e., 11 alpha- 11 beta-, 16 alpha-, 17 alpha-hydroxylations and 1-dehydrogenation. Availability and utilization of raw materials for industrial production of steroids of the estrane, androstane, and pregnane series are discussed. Among the current trends in steroid research of a practical nature, immobilization of enzymes and living cells and the spore process are emphasized as alternative techniques of steroid transformation of possible future importance. Efforts to recognize, in cell-free preparations, the components of steroid-transforming enzyme systems as well as the cellular mechanisms of control of their biosynthesis and activity are described in order to illustrate the main subjects of current basic investigation in steroid bioconversion.

Factors regulating the steroid 11-hydroxylation by non-germinating spores of Cunninghamella elegans (Lendner)

In the presence of malate or citrate sporangiospores of C. elegans were able to hydroxylate cortexolone with a rate twofold exceeding that of the control, water suspended spores. Analysis of the intracellular nicotinamide coenzyme pools revealed an increased NADPH:(NADP+ + NADPH) ratio, indicating more effective NADPH-generating systems in malate- or citrate-stimulating spores. Swollen spores remaining in the pregermination state, retained higher cortexolone-hydroxylating activity in the absence of malate and citrate. In these spores degradation of endogenous alanine and glutamic acid was observed. Possible NADPH-generating systems in C. elegans sporangiospores were discussed.