Abstract: A compound of the formula: ##STR1## wherein R.sub.1 is 3-pyridyl or 4-pyridyl; and R.sub.2 is hydrogen or lower alkyl (C.sub.1 -C.sub.3); or a nontoxic pharmaceutically acceptable salt thereof.

Abstract: Antibiotic LL-D42067.alpha. derived by aerobic fermentation of the microorganism Actinomadura madurae subspecies simaoensis NRRL 15734, useful as an antibacterial and antiparasitic agent.

Abstract: This disclosure describes four new antibacterial agents designated LL-CO8078.alpha..sub.1, LL-CO8078.alpha..sub.2, LL-CO8078.alpha..sub.3 and LL-CO8078.beta. produced in a microbiological fermentation under controlled conditions using a new strain of a new species of the genus Streptomyces called Streptomyces majorciensis Labeda, sp. nov., and mutants thereof. These new antibacterial agents are active against a variety of microorganisms and thus are useful in inhibiting the growth of such bacteria wherever they may be found. In addition, these agents are active as growth promotants in warm-blooded animals.

Abstract: Compounds of formula (I), and pharmaceutically acceptable salts thereof: ##STR1## wherein: X is CH.sub.2, O, S or NR.sub.4 wherein R.sub.4 is hydrogen or C.sub.1-4 alkyl;one of Y and Z is NR.sub.5 and the other is CR.sub.6 R.sub.7 wherein R.sub.5 is hydrogen, C.sub.1-4 alkyl or C.sub.1-4 acyl and R.sub.6 and R.sub.7 are either both hydrogen or together form an oxo group;R.sub.1 is hydrogen, C.sub.1-6 alkyl, C.sub.3-7 cycloalkyl, C.sub.4-7 cycloalkenyl or C.sub.1-4 alkyl substituted by C.sub.2-7 alkenyl, C.sub.2-7 alkynyl, C.sub.3-7 cycloalkyl, amino optionally substituted by one or two C.sub.1-4 alkyl or by C.sub.4-6 polymethylene optionally containing an oxygen atom or by phenyl C.sub.1-4 alkyl optionally substituted in the phenyl ring by C.sub.1-4 alkyl, C.sub.1-4 alkoxy, halogen or trifluoromethyl; andR.sub.2 and R.sub.3 are the same or different and are hydrogen, halogen, hydroxy, C.sub.1-4 alkyl C.sub.