Abstract: The present invention provides a novel bioactive substance having an antitumor activity and a process for producing it, and a medical use thereof. Namely, it provides a 12-membered ring macrolide compound represented by the following formula obtained from the incubation solution of Streptomyces sp. Mer. 11107 or a variant thereof, a pharmacologically acceptable salt thereof or a hydrate of them, and a process for producing it.

Abstract: The present invention provides a novel bioactive substance having an antitumor activity and a process for producing it, and a medical use thereof. Namely, it provides a 12-membered ring macrolide compound represented by the following formula obtained from the incubation solution of Streptomyces sp. Mer. 11107 or a variant thereof, a pharmacologically acceptable salt thereof or a hydrate of them, and a process for producing it.

Abstract: The present invention provides a novel bioactive substance having an antitumor activity and a process for producing it, and a medical use thereof. Namely, it provides a 12-membered ring macrolide compound represented by the following formula obtained from the incubation solution of Streptomyces sp. Mer.

Abstract: The present invention provides a novel bioactive substance having an antiangiogenic effect. The chemical compound represented by the formula (1) (wherein, R1 represents hydrogen atom, aldehyde group or a lower acyl group, R2 and R3 are the same as or different from each other and represent hydrogen atom or a lower alkoxy group or are combined to represent oxygen atom, R4 represents a lower alkyl group and R5 represents hydrogen atom or a lower alkyl group, provided that compounds in which R1 is aldehyde group, R2 and R3are different from each other and are hydrogen atom or methoxy group, R4 is ethyl group and R5 is hydrogen atom are excluded), a salt thereof or a hydrate thereof was isolated from the culture broth of genus Streptomyces and the structure thereof was analyzed.

Abstract: A method for preparing at least one hydroxycholesterol chosen from the group consisting of 25-hydroxycholesterol, 17,25-dihydroxycholesterol and 25,26-dihydroxycholesterol by biological hydroxylation of cholesterol, and the aforementioned dihydroxycholesterols. In the above biological hydroxylation, a microorganism is used which has the abovementioned hydroxylation capacity and which belongs to the genus Amycolata and the genus Sphingomonas.

Abstract: This invention provides DNA fragments for efficiently preparing a protein having asymmetric hydrolase activity for 4-substituted 1,4-dihydropyridine derivatives, transformants obtained by using such a DNA fragment, and a process for preparing the aforesaid enzyme. Specifically, an isolated gene derived from the chromosome of Streptomyces viridosporus and encoding a protein having asymmetric hydrolase activity for 4-substituted 1,4-dihydropyridine derivatives, plasmids having the aforesaid gene integrated thereinto, transformants obtained by using such a plasmid, and a process for preparing the aforesaid enzyme by using such a transformant are disclosed. A process for the enzymatic conversion of 4-substituted 1,4-dihydropyridine derivatives by using the aforesaid enzyme is also disclosed.

Abstract: A method for preparing at least one hydroxycholesterol chosen from the group consisting of 25-hydroxycholesterol, 17,25-dihydroxycholesterol and 25,26-dihydroxycholesterol by biological hydroxylation of cholesterol, and the aforementioned dihydroxycholesterols. In the above biological hydroxylation, a microorganism is used which has the abovementioned hydroxylation capacity and which belongs to the genus Amycolata and the genus Sphingomonas.

Abstract: This invention provides DNA fragments for efficiently preparing a protein having asymmetric hydrolase activity for 4-substituted 1,4-dihydropyridine derivatives, transformants obtained by using such a DNA fragment, and a process for preparing the aforesaid enzyme. Specifically, an isolated gene derived from the chromosome of Streptomyces viridosporus and encoding a protein having asymmetric hydrolase activity for 4-substituted 1,4-dihydropyridine derivatives, plasmids having the aforesaid gene integrated thereinto, transformants obtained by using such a plasmid, and a process for preparing the aforesaid enzyme by using such a transformant are disclosed. A process for the enzymatic conversion of 4-substituted 1,4-dihydropyridine derivatives by using the aforesaid enzyme is also disclosed.

Abstract: A biological process for producing steroids hydroxylated at the 25-position thereof comprises adding steroids (excluding cholesterol) to the cells or culture liquid of a microorganism of the genus Amycolata or Sphingomonas capable of hydroxylating the steroids at the 25-position thereof to convert a hydrogen atom bonded to a carbon atom at the 25-position of each steroid into hydroxyl group. By this process, steroids(other than cholesterol) can be biologically hydroxylated at the 25-position by using microorganisms other than those of the genus Streptomyces.

Abstract: Disclosed are 1,4-dihydropyridine derivatives represented by the general formula (I) and salts thereof, as well as optical active 1,4-dihydropyridine derivatives represented by the general formula (II) and salts thereof which are obtained from the derivative by biochemical reactions using microorganisms or enzymes and useful as preventive and therapeutic agents for ischemic heart diseases and hypertension. ##STR1## (wherein x and Y are H, NO.sub.2, CN, halogen; R.sup.1 and R.sup.2 are H, CHO, substituted alkylcarbonyl, crotonyl, cinnamoyl, alkoxycarbonyl, aryloxycarbonyl, benzyloxycarbonyl, carboxybenzoyl, or R.sup.1 and R.sup.2 taken together represent phthaloyl; n is an integer of 1 to 3).