The possible role of the superoxide ion in the induction of heat-shock and specific proteins in aerobic Drosophila cells during return to normoxia after a period of anaerobiosis.

In vitro cultured Drosophila melanogaster cells were shown to be aerobic and several kinetic parameters of their respiration were measured. This allowed us to define experimental conditions for a transient period of anaerobiosis followed by a reexposure to normal oxygenation. This treatment, applied without any change of temperature, induced not only the heat-shock proteins, but also a new specific peptide of 27 000 daltons and a twofold increase of the maximal rate of O2 uptake. This evokes a common molecular mechanism activated either by heat or by O2, which could involve the increase of the products of oxygen reduction such as the superoxide ion.

Catalase is induced by ecdysterone and ethanol in Drosophila cells.

Clones sensitive or resistant to ecdysterone and cultured in vitro were isolated from established cell line of Drosophila melanogaster. Ecdysterone (20-hydroxyecdysone), a hormonal steroid of critical importance in insect physiology, induces catalase activity in the sensitive clones. This catalase induction does not occur in clones known to be resistant to the the hormone. The important role of catalase as a scavenger for H2O2 in the aerobic cells (Drosophila cells in culture are consuming oxygen) led to the demonstration of catalatic properties of this induced enzyme. The peroxidatic property of catalase, useful in alcohol metabolism, was the reason for showing that ethanol can also induce catalase in Drosophila cells.

Anthrax in the Gambia: an epidemiological study.

Epidemiological data on 448 cases of human cutaneous anthrax from the Gambia showed that this particular strain of anthrax bacillus causes widespread morbidity and some mortality with, at the same time, subclinical infection. Analysis also showed that anthrax is not an occupationally related disease in the Gambia.The possibility of human-to-human spread, affecting all age groups and both sexes, by means of a communal toilet article was also shown. The fact that the strain is a good toxin producer but contains a weak antigen may have accounted for the repeated clinical infection and the fact that antibody titres were generally transient. Subclinical infection in animals was also found, particularly in sheep and goats, and also, with an unusually low mortality, in cows. Insect vectors were not excluded, but were unlikely. Vultures may spread the disease from village to village. Some possible public health and immunization procedures are discussed, with a view to containing this difficult problem in this part of west Africa.