Prostaglandins and congeners XXIII (1). Synthesis of 15-deoxy-16-hydroxy-16-methylprostanglandins. The importance of the C13--C14 trans double bond for bronchodilator activity

The synthesis and bronchodilator activity in the guinea pig of several 15-deoxy-16-hydroxy-16-methylprostaglandin analogs is described. The E2 (VIa) and E1 (VIb) analogs are potent bronchodilators comparable in activity to the natrual prostaglandins, but possessing a longer duration of effect. Replacement of the C13--C14 trans double bond by a cis double bond or an ethylene linkage causes a substantial diminishment of this activity.

Evidence that spo0A mutations are recessive in spo0A-/spo0A+ merodiploid strains of Bacillus subtilis

The spo0A locus contains two types of closely linked mutations that block sporulation at stage 0: spo0A mutations (the most pleiotropic of the stage 0 markers) and spo0C mutations. It was previously thought that spo0A mutations were dominant in merodiploids of Bacillus subtilis, whereas spo0C mutations were recessive. We have shown that spo0A mutations were recessive when spo0A-/spo0A+ merodiploids were made in the genetic backgrounds of strains that were resistant to antibiotic produced by the wild-type strain. Reinvestigation of cultures of spo0A-/spo0A+ merodiploids constructed in the antibiotic-sensitive spo0A strain showed that they contained the spo0A allele at a low frequency, and they produced very few haploid Spo- segregants. These facts indicated that the cultures contained mostly homogenotic (spo0A+/spo0A+) cells. The reason for the poor survival of the spo0A-/spo0A+ merodiploids in the genetic background of the antibiotic-sensitive strain was not clear, but several possible explanations were given. It may have been related to the diploid state of other genes in the same merodiploid cells. The previous indication that spo0A mutations were dominant seems to have been based on the properties of a rare class of Spo- segregants that were probably selected in the presence of antibiotic.

Control of anthocyanin synthesis by the C locus in maize

Alleles at the C locus in maize include C, one of the complementary genes required for anthocyanin pigmentation in the aleurone tissue of the mature kernel; C-I, dominant inhibitor of pigmentation; and c, recessive colorless. The recessive colorless alleles can be differentiated into two distinct forms: c-p (p for positive), conditional colored, develops pigment in the light during germination; c-n (n for negative), colorless, fails to develop pigment at any time. Four-point linkage data support the differentiation of c-p (in the alleles derived from either W22 or K55 inbreds) from c-n. Light and germination conditions are both required for anthocyanin synthesis in c-p tissue, but light "induction" and germination "induction" are two separable events inasmuch as the light stimulus can be stored. The ratio between the two major pigments, cyanidin and pelargonidin, is lowered in c-p tissue relative to that in dominant colored (C) tissue for the W22 allele and background but not for the K55 allele and background. Segregation tests reveal that the difference in the cyanidin-to-pelargonidin ratio in the C and the c-p tissue of W22 background is associated with the C locus. Several properties of the C locus, including anomalous allelic functions, stage- and properties of the C locus, including anomalous allelic functions, stage- and condition-dependent anthocyanin synthesis controlled by its multiple allelic series, and tissue-specific function, suggest that C may be a regulatory locus in the control of anthocyanin synthesis in aleurone tissue.

Effect of hypocholesterolemic drug AY9944 on cultured nervous tissue: morphologic and biochemical studies

The effects of different concentrations of the hypocholesterolemic drug AY9944, an inhibitor of delta7-reductase, on organotypic cultures of fetal mouse spinal cord, were studied by light and electron microscopy. Exposure to 10(-6)M produced no observable changes. After 6 hours exposure to 10(-4)M, dense membrane-bound inclusions were occasionally observed in neurons. After 24 hours exposure to 10(-4)M, numerous cytoplasmic inclusions occurred in neurons, glia and macrophages. The form of these inclusions varied but were predominantly of two types; concentric, loosely-packed lamellae resembling membranous cytoplasmic bodies (MCB) of Tay-Sachs disease and irregular dense bodies. They were identical to those observed in our previous in vivo study. Prolonged exposure to the drug at 10(-4)M caused an increased number of inclusions in all cell types. Eventually the cultures degenerated. The number of inclusions increased for at least 38 days following a 2-5 day exposure to AY9944 at 10(-4)M. However, by 70 days, although inclusions persisted, the cultures were mostly astrocytic. In long-term cultures, in addition to these inclusions, curved or straight electron-dense paired profiles were seen in some cells, presumably macrophages. Biochemical analysis of cultures exposed to 10(-4)M revealed the continuous presence of delta7, 24-cholesta-diene-3beta-ol and 7-dehydrocholesterol even after the drug wa removed from the cultures. In our previous animal experiments, intracytoplasmic inclusions and abnormal sterols with a double bond at the 7 position disappeared quickly after discontinuation of the drug. Therefore, the results obtained in our present in vitro experiments are different in this regard from the in vivo studies of AY9944.

Changes in brain hydrolytic enzyme activities in rats treated with cholesterol biosynthesis inhibitor, AY9944

Intraperitoneal administration of AY9944 causes accumulation of 7-dehydrocholesterol, appearance of abnormal neuronal cytoplasmic lamellar inclusions containing acid phosphatase activities, and degeneration of oligodendroglial cells. In the present study, we attempted to correlate appearance and disappearance of abnormal inclusions, oligodendroglial degeneration, activities of lysosomal enzymes, and accumulation of 7-dehydrocholesterol. One group of 5-day-old rats received daily injection of AY9944, 30 mg/kg, for 30 days. Other groups received the same daily dosage but only in 10 consecutive days, starting from 5, 15, 25, and 35 days, respectively. Activities of 13 brain hydrolytic enzymes were determined. In the first group, activities of most enzymes increased over the controls, reaching the peak between the 15th and 25th day, corresponding to the maximum appearance of the neuronal inclusions and degenerating oligodendroglia. Despite the continued administration of AY9944 and the high tissue concentration of 7-dehydrocholesterol, activities of most enzymes declined after 25 days to relatively steady levels somewhat higher than controls. In the group which received 10-day injections, enzyme activities reached the peak at the end of the injections and then rapidly returned to normal within 10 days thereafter, corresponding to the appearance and disappearance of the abnormal inclusions. However, 7-dehydrocholesterol continued to increase for 10 days after the drug administration was discontinued. AY9944 had no direct effect on any of the enzymes in vitro. There appears to be generalized lysosomal activation concomitant with formation of abnormal neuronal inclusions in the experimental conditions.