STRUCTURE AND BIOLOGICAL ACTIVITY OF LIPIARMYCIN
Actinoplanes deccanensis ATCC21983, the producer of antibiotics lipiarmycin A3 and A4, furnished also a related antibiotic designated lipiarmycin B, active against Gram-positive bacteria, including anaerobes, and against Neisseria. The structures of the two major components, B3 and B4, were elucidated from their physico-chemical properties, XHand 13C NMRspectra and fast atom bombardmentmass spectra data in comparison with lipiarmycins A3andA4.
Lipiarmycin, a new antibiotic from Actinoplanes. II. Isolation, chemical, biological and biochemical characterization.
Lipiarmycin, a metabolite of Actinoplanes deccanensis nov. sp. (PARENTI et al.), has been isolated in pure form. It has a molecular formula C52 CONGRUENT TO 54H74 CONGRUENT TO 76Cl2O19, (M.W. = 1,073 CONGRUENT TO 1,099). From its chemical and physico-chemical characteristics, lipiarmycin can be considered a new antibiotic. Lipiarmycin is highly active against Gram-positive bacteria, including strains resistant to the medically important antibiotics and protects mice experimentally infected with Streptococcus haemolyticus. Liparmycin inhibits growth of susceptible bacteria by interfering with RNA synthesis.
Interaction of Diclofop-Methyl and MCPA on Wild Oats (Avena fatua)
Diclofop-methyl {methyl 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoate} loses part of its activity on wild oats (Avena fatua L.) when it is applied in combination with ester or amine formulations of MCPA {[4-chloro-o-tolyl)oxy] acetic acid.} Uptake of diclofop-methyl is reduced in the presence of commercial formulations of MCPA, particularly amine formulations, which are only partly compatible with the diclofop-methyl formulation. With added MCPA, regardless of formulation, hydrolysis of diclofop-methyl to the acid diclofop is slowed down, both in intact wild oat plants and in a crude leaf extract. At the same time, conversion of any acid formed to inactive conjugates is accelerated in the presence of MCPA. It is concluded that the loss of activity of diclofop-methyl by MCPA can be accounted for by the effects of MCPA on uptake and metabolic conversion of diclofop-methyl.