Abstract: Carbacephem and cephem compounds represented by the formula: ##STR1## [Wherein X is S or CH.sub.2 ; n is an integer of 1 to 5; R.sub.1 is an unsubstituted or substituted heterocyclic group (where the heterocyclic group is a 5- or 6-membered heterocyclic group having 1 to 4 of O, S and N); R.sub.2 is a group represented by the formula: ##STR2## (where R.sub.4 is an unsubstituted or substituted phenyl or 2-aminothiazolyl) or a group represented by the formula: ##STR3## (where R.sub.5 is an unsubstituted or substituted lower alkyl); R.sub.3 is hydrogen, an alkali metal, an alkaline earth metal, an organic ammonium group or an ester residue, and R.sub.1 may be a quaternary ammonium group, where --CO.sub.2 R.sub.3 represents --CO.sub.2.sup.- ] have strong antibacterial activity against Gram-positive and Gram-negative bacteria, and are useful for treating various infections.

Abstract: Disclosed is a novel physiologically active substance, K-26, a process for preparation thereof and a pharmaceutical composition containing the same. The composition of matter, K-26, is useful as a hypotensive agent.

Abstract: Carbacephem compounds represented by the formula: ##STR1## [wherein R.sub.1 is a lower alkylsulfonyloxy, unsubstituted or substituted arylsulfonyloxy, azido, cyano, carbamoyloxy, unsubstituted or substituted heterocyclic thio ("heterocyclic" means a 5- or 6-membered heterocyclic group having 1 to 4 O, S or N atoms), unsubstituted or substituted lower alkylthio, or unsubstituted or substituted arylthio group; R.sub.2 and R.sub.3 are groups frequently used in the cephalosporin chemistry] have strong antibacterial activity against Gram-positive and Gram-negative bacteria, and are useful for curing various infections.

Abstract: 3, 3", 4"-Tri-O-acylspiramycin I represented by the formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are the same or different groups, and at least one of the groups is a straight or branched chain alkylcarbonyl group represented by --COC.sub.m H.sub.2m+1 wherein m is an integer of 2-4 and the other group(s) are straight or branched chain alkylcarbonyl group(s) represented by --COC.sub.n H.sub.2n+1 wherein n is an integer of 1-4, and its pharmacologically acceptable acid addition salts.

Abstract: Disclosed is a novel physiologically active substance K-4 which has a hypotensive activity, a process production thereof and a pharmaceutical composition containing the same.

Abstract: The antibacterial compounds 7-deazaadenosine and 7-deazinosine are produced by fermentation of a new microorganism of the genus Micromonospora. At least one of the active substances is isolated from the culture medium.

Abstract: New antibacterial compounds, XK-62-3 and XK-62-4, are produced by fermentation of microorganisms belonging to the genus Micromonospora. The compounds are accumulated in the culture liquor and are isolated therefrom.

Abstract: New antibacterial compounds, XK-62-3 and XK-62-4, are produced by fermentation of microorganisms belonging to the genus Micromonospora. The compounds are accumulated in the culture liquor and are isolated therefrom.

Abstract: New antibiotic compounds, Fortimicin factors D and KE are produced by fermentation of microorganisms belonging to the genus Micromonospora. The antibiotic compounds are accumulated in the culture liquor and are isolated therefrom. A semisynthetic method of producing Fortimicin KE utilizing Fortimicin D is also disclosed.

Abstract: New antibiotic compounds, Fortimicin factors KF and KG are produced by fermentation of microorganisms belonging to the genus Micromonospora. The antibiotic compounds are accumulated in the culture liquor and are isolated therefrom.

Abstract: A novel antibacterial compound, XK-99, is produced by fermentation of an organism belonging to the genus Micromonospora. The compound is isolated from the microbial cells and culture liquor.

Abstract: New antibiotic compounds, Fortimicin factors D and KE are produced by fermentation of microorganisms belonging to the genus Micromonospora. The antibiotic compounds are accumulated in the culture liquor and are isolated therefrom. A semisynthetic method of producing Fortimicin KE utilizing Fortimicin D is also disclosed.

Abstract: A new antibiotic, Fortimicin C, is produced by fermentation of a microorganism belonging to the genus Micromonospora. The antibiotic is accumulated in the culture medium and is isolated therefrom.

Abstract: A new antibiotic, Fortimicin C, is produced by fermentation of a microorganism belonging to the genus Micromonospora. The antibiotic is accumulated in the culture medium and is isolated therefrom.

Abstract: The antibiotic XK-62-2 is produced by fermentation of microorganisms belonging to the genus Micromonospora. The antibiotic is accumulated in the culture liquor and is isolated therefrom.

Abstract: A novel series of antibiotics designated the XK-88 series are produced by culturing a microorganism belonging to the genus Streptomyces in a nutrient medium and thereafter recovering the antibiotics from the culture liquor.

Abstract: A new antibiotic, Fortimicin A, is produced by fermentation of a microorganism belonging to the genus Micromonospora. The antibiotic is accumulated in the culture medium and is isolated therefrom.

Abstract: A novel series of antibiotics designated the XK-88 series are produced by culturing a microorganism belonging to the genus Streptomyces in a nutrient medium and thereafter recovering the antibiotics from the culture liquor.BACKGROUND OF THE INVENTIONThe present invention relatees to novel antibiotics and a process for the production thereof. More specifically the present invention relates to novel antibiotics designated, XK-88-1, XK-88-2, XK-88-3 and XK-88-5 and a process for producing such antibiotics.Antibiotics which exhibit activity against a borad spectrum of bacteria are always in demand. To this end, a new species of microorganism has been isolated from soil located in Tajima-cho, Hofu-shi, Yamaguchi-ken, Japan. This new species, when cultured, produces a series of new antibiotics, the XK-88 series, all of which exhibit strong antibacterial activity against various Gram-positive and Gram-negative bacteria.

Abstract: A new antibiotic, Fortimicin B, is produced by fermentation of a microorganism belonging to the genus Micromonospora. The antibiotic is accumulated in the culture medium and is isolated therefrom.