4-Dedimethylamino-4-epiamino-5a,6-anhydrotetracycline

Zusammenfassung Die Isolierung sowie die chemischen, biologischen und physikalischen Eigenschaften von 4-Dedimethylamino-4-epiamino-5a,6-anhydrotetracyclin werden beschrieben. Die Beziehungen zu anderen Anhydrotetracyclinen werden diskutiert.     

Temperature-induced reversal of dominance of variegation in ‘Ornamental kale’

Résumé La transmission de l'albinisme panaché deBrassica oleracea L. ne dépend que d'un seul facteur. Chez les hétérozygotes ce caractère apparaît à basse température (7°C), mais pas à haute température (21°C). Chez les homozygotes le caractère se manifeste probablement toujours, tout en restant peu prononcé à des températures plus élevées. Ainsi il y a une inversion du caractère dominant avec changement de température.     

Isolation of an HTLV-III-related retrovirus from macaques with simian AIDS and its possible origin in asymptomatic mangabeys

Acquired immune deficiency syndrome (AIDS) has become a worldwide epidemic, so the development of vaccines and antiviral agents effective against the causative agent, human T-lymphotropic virus type III (HTLV-III), is vital. This work would be greatly simplified if a suitable animal model could be developed. Here we report the isolation of an HTLV-III-related retrovirus, STLV-III/Delta, from rhesus macaques (Macaca mulatta) with transmissible simian AIDS (SAIDS) and from asymptomatic sooty mangabeys (Cercocebus atys). SAIDS was initially diagnosed in several macaques previously inoculated with tissue homogenates of mangabey origin. Western blot analysis of both the mangabey and macaque sera demonstrated the presence of antibody cross-reactive primarily with the HTLV-III proteins p24 and p61. In a related experiment, analysis of these same sera revealed simian antibody to STLV-III/Delta proteins similar, but not identical, to those of HTLV-III with estimated relative molecular masses (Mrs) of 16,000 (16K), 26K, 35K, 45K, 60K and 110K. Infection of the mangabey, an African primate, with an HTLV-III-related virus may provide a clue to the origin of HTLV-III in humans. The apparent difference in susceptibility to SAIDS-like disease between infected macaques and mangabeys suggests that these species may respond differently to STLV-III infection.     

Comparative effects of ouabain, natriuretic factor and ammonium chloride in the toad urinary bladder

Electrical changes and direct effects on Na-K ATPase activity induced by an endogenous digitalis-like natriuretic factor (NF), NH4Cl and ouabain were studied in toad bladders. NF inhibited the SCC and the Na-K ATPase activity in a similar manner to ouabain, but induced a greater increase in calculated direct current resistance (R) (p less than 0.05). NH4Cl was a weak inhibitor of Na-K ATPase activity, although it produced steeper SCC inhibition slopes than those observed with ouabain or NF (p less than 0.01). The data suggested the same mechanism of action of NF and ouabain on the sodium pump, with an additional effect of the former on apical sodium permeability of the cells and/or closure of paracellular routes leading to an increased tissue resistance. In contrast, the effects of NH4Cl were mostly compatible with intracellular inhibition of apical sodium entry into the cell.