Acetic acid vapour as a resource: Threshold differences among threeDrosophila species

Summary Acetic acid vapour is utilized as an energy source up to a threshold where it becomes a stress in 3Drosophila species. The threshold ranking isD. melanogaster» D. simulans>D. immigrans, which qualitatively parallels that for ethanol. The capacity to use nutritive vapours appears to be very important inDrosophila ecology.I thank Gary Spence for technical assistance, and the Australian Research Grants Committee for partial financial support.     

Transdermal uptake of a peptide hormone: Inhibition by calcitonin eardrops of induced osteolysis in guinea-pig ossicles

Summary In view of a recent proposal that calcitonin injections may arrest the bony pathology of otosclerosis, we have tested the possibility of obtaining locally effective concentrations by giving salmon calcitonin in eardrops. Osteolysis of guinea-pig ossicles induced by injecting parathyroid hormone shortly before explantation was markedly inhibited by 3 days prior instillation of the calcitonin in an aqueous vehicle or in dimethyl sulphoxide, but not by a solution in propylene carbonate.We thank Mr R. B. Christie, Armour Pharmaceutical Company Limited, Eastbourne for the supply of synthetic salmon calcitonin and Mr A.M. Oliver, for statistical examination of the data.     

Some parasites of paddlefish ( Polyodon spathula ) from the Yellowstone River, Montana

One species of copepod ( Ergasilus elongatus ), one trematode ( Diclybothrium hamulatum ), two nematodes ( Camallanus oxycephalus and Contracaecum sp.), and two cestodes ( Marsipometra hastata and M. parva ) were recovered from 17 paddlefish ( Polyodon spathula ) collected from the Yellowstone River, Montana, on 11 and 18 May 1973. The male paddlefish averaged 69.4 nematodes and 157.6 cestodes per infected fish while the females averaged 12.0 nematodes and 415.7 cestodes. The higher intensity of cestode infection in female paddlefish was attributed to their larger size and consequent greater intake of food resulting in more exposure to the cestode intermediate hosts ( Cyclops bicuspidatus ).     

Isolation of large sheets of frog skin epidermis

Zusammenfassung Nach Trypsinbehandlung abgetrennte Froschepidermis von bis zu 5 cm ø zeigt dieselbe Potenialdifferenz, Stromkurzschluss- und Sulfatpermeabilität wie die unveränderte Froschhaut. Die präparierte Epidermis besitzt fast keine Hautdrüsen, Jedoch fast völlig verschlossene Drüsenausführungsgänge.

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This work was supported by grants from the U.S. Public Health Service No. AM 05865 and No. GM 00899.     

Reproductive characteristics of two kokanee stocks in tributaries to Flaming Gorge Reservoir, Utah and Wyoming

The charaeteristics of kokanee ( Oncorhynchus nerka ) spawning stocks in the Green River and Sheep Creek (tributaries to Flaming Gorge Reservoir) are described as observed in fall 1985 and spring 1986; the time of spawning; length, age, and sex structure of the stocks; fecundity and egg retention; density of eggs in redds; and the timing of downstream drift of emerging fry. The time of spawning, length-frequency distributions of spawning fish, and egg density in redds differed between the two stocks, but other differences were not observed.     

Depletion of synaptic vesicles at the frog (Rana pipiens) neuromuscular junctions by tetraphenylboron.

At the frog neuromuscular junction tetraphenylboron produced a decrease in miniature endplate potential amplitude, accompanied by a decrease in the number but not the size of synaptic vesicles.