Steroid transformation by microorganisms ppt

A preparation of living Arthrobacter simplex cells immobilized in polyacrylamide gel, which showed steroid-Δ 1 -dehydrogenase activity, was studied. The entrapped microorganisms catalyzed the transformation of cortisol to prednisolone and this reaction was followed spectrophotometrically or with the aid of thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC). About 40% of the original activity found with free bacteria was retained after immobilization. The steroid dehydrogenase activity of polyacrylamide-entrapped A. simplex could be raised to a minor extent in alcoholic solvents or by addition of a cofactor such as menadione. On incubation in various nutrient media, on the other hand, the activity could be increased considerablyl, usually 7–10 times. Possible causes for the observed increase in activity have been investigated, and microbial growth of the original entrapped microorganisms appears to be the major reason. Frozen activated preparations of immobilized A. simplex showed only a small loss of activity on storage for at least four months. A semicontinuous batch wise operation with immobilized A. simplex in different nutrient media was carried out. At the end of the experiment the steroid transformation capacity was g steroid per day per g gel (wet weight).

Intravenously administered glucocorticoids , such as prednisone , are the standard of care in acute GvHD [7] and chronic GVHD. [24] The use of these glucocorticoids is designed to suppress the T-cell-mediated immune onslaught on the host tissues; however, in high doses, this immune-suppression raises the risk of infections and cancer relapse. Therefore, it is desirable to taper off the post-transplant high-level steroid doses to lower levels, at which point the appearance of mild GVHD may be welcome, especially in HLA mis-matched patients, as it is typically associated with a graft-versus-tumor effect. [ citation needed ] . Cyclosporine and tacrolimus are inhibitors of calcineurin. Both substances are structurally different but have the same mechanism of action. Cyclosporin binds to the cytosolic protein Peptidyl-prolyl cis-trans isomerase A (known as cyclophilin), while tacrolimus binds to the cytosolic protein Peptidyl-prolyl cis-trans isomerase FKBP12. These complexes inhibit calcineurin, block dephosphorylation of the transcription factor NFAT of activated T-cells and its translocation into the nucleus [25] . Standard prophylaxis involves the use of cyclosporine for six months with methotrexate. Cyclosporin levels should be maintained above 200 ng/ml [26] . Other substances that have been studied for GvHD prophylaxis include, for example: sirolism, pentostatin and alemtuzamab [27] .

Development of pharmaceutical industry is currently aimed at introducing biotechnological processes on a large-scale and thereby replacing multiple-stage chemical syntheses. Actinobacteria are efficient biocatalysts of many processes involving steroid bioconversion, which hold considerable importance for the synthesis of hormonal drugs. The potential to catalyze the conversion of a broad spectrum of steroid substrates makes it possible to expect efficient utilization of these microorganisms in development of new technologies of manufacturing steroid pharmaceutical substances. The review is a first attempt to systematize data on the potential of actinobacteria to catalyze diverse reactions of steroid transformation (such as hydroxylation, introduction and reduction of double bonds, oxidation of steroid alcohols, reduction of ketones, side chain de-esterification and degradation, etc.), with emphasis on processes of practical biotechnological importance and progress in steroid bioconversion over the last ten years.

HCG : It is strongly recommended that HCG be a part of your testosterone cycle. The addition of HCG will prevent testicular atrophy, which will occur with testosterone use. When we use testosterone or any anabolic steroid , we suppress our natural testosterone production. If we are supplementing with testosterone, this isn’t a concern during the cycle as we are providing our body with the testosterone it needs. However, HCG will keep the natural production online, which will make post cycle recovery far more effective. A dose of 250-350mg two times per week will suffice for most men. For information on post cycle therapy (PCT) please visit How to Come off Steroids .

Steroids shattered the limitations of my body. I first sensed their effects while bench-pressing dumbbells. I usually peak at 85lb each, or 170lb total. But after 10 repetitions with the 85s I was stunned: it felt like a warm-up! With a degree of trepidation - we're talking weights that, if mishandled, could break a wrist or some ribs - I picked up the 90-pounders, which I'd never attempted. They went up easily and I ripped out 10 reps. It was an out-of-body sensation: somebody else's arms were pushing those weights, someone else's pectorals flexing and contracting.

Steroid transformation by microorganisms ppt

steroid transformation by microorganisms ppt

HCG : It is strongly recommended that HCG be a part of your testosterone cycle. The addition of HCG will prevent testicular atrophy, which will occur with testosterone use. When we use testosterone or any anabolic steroid , we suppress our natural testosterone production. If we are supplementing with testosterone, this isn’t a concern during the cycle as we are providing our body with the testosterone it needs. However, HCG will keep the natural production online, which will make post cycle recovery far more effective. A dose of 250-350mg two times per week will suffice for most men. For information on post cycle therapy (PCT) please visit How to Come off Steroids .

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