The chemistry of the antibiotics chrysomycin A and B. Antitumor activity of chrysomycin A

The yellow antibiotic chrysomycin, isolated in crystalline form in 1955, is found to consist of two closely related components, a major one, chrysomycin A, and a minor one, chrysomycin B. They differ only through the replacement of a vinyl group of chrysomycin A by methyl in chrysomycin B. The absorption spectrum of chrysomycin A is identical with that of the antitumor antibiotic toromycin (gilvocarcin V, 2064A), while that of chrysomycin B is similarly identical with the one of gilvocarcin M (2064B). The structures of these antibiotics (toromycin, the glivocarcins, and 2064A and B) have been elucidated recently. Chrysomycins A and B thus contain the same chromophores as gilvocarcins V and M, respectively; comparison of 1H and 13C NMR spectra confirms this identity. The chrysomycins differ from these other antibiotics in the C-glycosidic side-chain, which is a methylpentose in the gilvocarcins, a 3,5-dimethylpentose in the chrysomycins. Structure and relative configuration of the latter are given. The biological activity and possible biosynthesis of the chrysomycins are discussed.

Preparation and physiological properties of alkyl esters of 2,3-dihydroxypropionic acid

In order to investigate the physiological behavior of alkyl esters of 2,3-dihydroxypropionic acid two such compounds have been synthesized. One of them, the 1-dodecylester of 2,3-ditetradecyloxypropionic acid was subjected to digestion by pancreatic lipase. The substance remained unaffected. For an in vivo experiment a doubly labelled homolog, the [1'-14C]decyl ester of 2,3-di[1'-3H]hexadecyloxypropionic acid was synthesized. This compound was fed by stomach tube to three groups of male albino rats. The experimental animals were killed after 2,4 and 6 h, those of the control groups after 6 h. Blood, urine, small intestines and livers were examined for radioactivity. From the recovery rates it could be derived that the molecule had been metabolized and absorbed. Obviously, the alkyl chain labelled with 14C was split off first and the alkyl chains labelled with 3H were split off thereafter. As the substance is metabolized in vivo it cannot be utilized as a 'non-fattening fat'.

Ro 13-9904/001, a novel potent and long-acting parenteral cephalosporin

Ro 13-9904/001 is a novel parenteral cephalosporin antibiotic with potent in vitro activity against a wide range of beta-lactamase-producing and non-producing pathogens. In addition, Ro 13-9904/001 proved to possess a very long plasma half-life and, as a consequence, high prophylactic in vivo effectiveness.

[Sports in prevention of postural defects]

Posture results from numerous alternating factors and reflects the attitude of an individual towards a definite situation. If the different conditions, namely the capacity and the willingness of posture, do not correspond to the requirements of the situation the "normal" erect posture will change. The development from abnormal posture into irreversible abnormalities and damages in posture is easy. In order to eliminate these risks one can try to reduce the potential of the situation on the one hand and to improve the capacity of the individual through adequate physical exercise on the other. The practice of daily physical activity at school or during leisure time is the best way to compensate for lack of exercise, to modify prolonged unfavourable situations, and to develop the physical capacity in such a way that dangerous loads can be supported without damage. The versatility of training, in combination with adequate gymnastical exercises and sports help to educate the sense of posture and movement with the effect that erect posture can be adopted and maintained. But only children who feel that erect posture is reflecting their personal image will finally keep the erect posture. Special attention is given to elite training in childhood and adolescence, when the vertebral column is particularly exposed to danger by the intensity of the training and must be protected against deformations by carefully chosen preventive measures.