In terms of western medicines, over 3000 antibiotics - including penicillin and tetracycline - are obtained from micro-organisms. Another product of micro-organisms i.e. cyclosporin was developed from a soil fungus. It revolutionized heart and kidney transplant surgery by suppressing immense reactions. Many micro-organisms have their own antibiotics and scientists have not yet been able to fully identify their potential uses. Biotechnology can now help to isolate useful genes and transfer them to different species to produce substances such as enzymes required in large quantities for curative purposes. Unicellular bacteria also produce the antibiotics such as gramicidin, olymyxin B and bacitracin respectively. Some micro-organisms (fungi, actinomycetes and bacteria) are used to transform chemically synthesized steroid hormones to resemble natural hormones for clinical use.