Temperature dependence of neurotransmitter release in the antarctic fishPagothenia borchgrevinki

Summary The quantal contents of endplate potentials from extraocular muscles of an antarctic fishPagothenia borchgrevinki were measured over a range of temperatures. Quantal release was maximal at about 5°C but showed little dependence on temperature between –2°C and 10°C. Above 10°C quantal content declined until release ceased about 18°C. In view of the fact that the ambient temperature at which these fish live is constant at –1.9°C, the results suggest thatPagothenia borchgrevinki is only partially adapted to its environment despite 25 million years acclimatization.The authors wish to thank the staff of New Zealand's Scott Base, Antarctica, without whose cooperation the work would have been impossible. Mr J. Quinn of the Auckland University Physiology Department gave invaluable assistance with computing and electronics and the Antarctic Division of the New Zealand Department of Scientific and Industrial Research provided transportation and logistic support. The project was financially supported by the New Zealand University Grants Committee and the Auckland University Research Committee. S.P. was a Senior Fellow of the N.Z. Medical Research Council.     

Rate-compensated synaptic events in antarctic fish: Consequences of homeoviscous cold-adaptation

Summary At ambient sub-zero temperatures, muscles from antarctic fish produce spontaneous postsynaptic currents (MEPCs) of significantly shorter duration than those of temperate fishes. Fast decay of antarctic MEPCs is a predictable consequence of the increased membrane fluidity attributable to fatty acid unsaturation in cold-adapted animals.We wish to thank the Antarctic Division of the New Zealand Department of Scientific and Industrial Research, and the staff of Scott Base, without whom this work could not have been done. The work was supported financially by grants from the New Zealand University Grants Committee and from the Auckland University Research Committee. We are also grateful to members of the United States Antarctic Research Program, in particular Dr A. L. DeVries, for advice and assistance.     

Linalool from the cotton stainerDysdercus superstitiosus (F.) (heteroptera: Pyrrhocoridae)

Summary The isoprenoid linalool, together with several straight carbon-chain aliphatic materials, has been found in the scent glands of the cotton stainerDysdercus superstitiosus (F.)We thank the British Inter Universities Council and Bayero University Research and Higher Degrees Committee for their financial support, Dr B.W. Staddon for his valuable assistance, Dr D.E. Games for arranging mass spectral facilities.     

The invasion and growth ofBabesia bovis in tick tissue culture

Summary Erythrocytic forms ofBabesia bovis inoculated into cell cultures of the tickBoophilus microplus invaded the tick cells and showed multiplication for up to 48 h after inoculation.Acknowledgment. We thank Mr. G.B. Mirre and Mrs M. Steinhoffer for able technical assistance during the course of the work. We also thank Dr. H.M.D. Hoyte, Parasitology Department, University of Queensland, for the use of an electron microscope. The work was supported by funds from the Australian Meat Research Committee.     

Limitations on visual food-location in the planktivorous antarctic fishPagothenia borchgrevinki

Summary The visual threshold for food-location in the antarctic fishPagothenia borchgrevinki, is compared with light conditions and food availability under the ice. Even under the most favourable conditions for vision,P. borchgrevinki is operating close to its visual threshold and must often depend on non-visual mechanisms of prey detection.We thank J. D. Cargill and H. S. B. Weix for technical assistance, and the staff of Scott Base for their support. Funding was provided by the New Zealand University Grants Committee, and logistic support by the Antarctic Division of the Department of Scientific and Industrial Research.     

Volatile constituents of the scent gland reservoir ofAspavia acuminata

Summary Volatile components of the scent gland complex of the adult bug ofAspavia acuminata, an agricultural pest from Nigeria, have been identified by the technique of combined gas chromatograph-mass spectrometry. Of specific interest is the presence in the gland reservoir of hex-2-enal, 4-oxo-hex-2-enal and 4-oxo-oct-2-enal.The author is grateful to the Bayero University Research and Higher Degrees Committee for financial support, Dr B. W. Staddon for his valuable assistance, Dr D. E. Games for arranging mass spectral facilities.     

Microinjection of synthetic protein kinase inhibitor into single barnacle muscle fibers before and after cyclic AMP

Summary Single muscle fibers from the barnacleBalanus nubilus have been used as a preparation to see if a synthetic 20-residue PKI (5-24)-peptide is able to block or reverse the stimulatory response of the ouabain-insensitive Na efflux to injected cAMP. The results obtained show that this peptide behaves as a powerful inhibitor of the cAMP-mediated response and is also able to partially reverse the sustained stimulation of the Na efflux observed in ouabain-poisoned fibers following the injection of subunit A of cholera toxin.Warmest thanks to Prof. E. H. Fischer and Kurt Diltz for a sample of sPK1. This work received support from NSF, the Graduate School Research Committee and from NIH through a General Research Support Grant to the University of Wisconsin Medical School.     

Locomotory energetics in a marsupial (Antechinomys spenceri) and a rodent (Notomys alexis)

Summary Steady state oxygen consumption was compared in a rodentNotomys alexis and a marsupialAntechinomys spenceri. The marsupial was found to diverge from predicted eutherian energetic patterns.N. alexis appears to use energy storage as a significant part of the step cycle before becoming bipedal. Aerobic scope and heat storage during running are similar in both species.We thankP. Baverstock, C. Watts andH. Aslin for the use of theAntechinomys, Ms.B. Whaite for assistance. Supported by Grants from the Nuffield Foundation, the Ingram Trust and the Flinders University Research Committee to RVB.     

Niche width of parasites in species-rich and species-poor communities

Summary Niche width of ectoparasites of marine fishes, as measured by host range and microhabitat width, is not affected by the number of species in a community. There is no reduction in species numbers of Monogenea due to greater numbers of other parasite species, and frequencies of infection with Monogenea are greater in tropical, species-rich communities.Supported by grants from the Australian Research Grants Committee and the University of New England. M. Heap provided valuable technical assistance, and F. Roubal made his data onAcanthopagrus australis available to me.     

Multiple forms of monoamine oxidase in developing Xenopus

Zusammenfassung Das Isoenzymmuster der Monoaminoxidase verändert sich während der frühen Entwicklung der Larven vonXenopus laevis. Die Anzahl elektrophoretischer Banden verkleinert sich während der Entwicklung von vier auf eine.

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The author was supported by a grant from the Cleveland State University Faculty Research Committee. The author would like to express his thanks toJohn Y. Pun the president of Bionix (El Cerrito, California) for the use of the apparatus.     

Tris as a blocking agent of the proton-sensitive component of the sodium efflux in barnacle muscle fibers

Zusammenfassung Studien über den Natriumtransport in den Muskeln vonBalanus sp. haben bewiesen, dassTris den protonempfindlichen Anteil der Natrium-Pumpe verlangsamt und dasTris hauptsächlich an der Aussenseite des Sarkolemms aktiv ist.

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Acknowledgments. This work was supported in part by grants from the Wisconsin Heart Association, the Medical School Research Committee, the Graduate School Research Committee and the Office of Naval Research. Our thanks are due to Mr.Geoffrey Chambers for technical assistance. E.Y.T. is a Postdoctoral Fellow of the Wisconsin Heart Association. B.G.D. is a Visiting Scientist of the American Heart Association.     

Acetic acid pretreatment of initiated epidermis inhibits tumour promotion by a phorbol ester

Summary Mouse skin initiated with 7,12-dimethylbenz(a)anthracene and then exposed to multiple treatments of acetic acid, shows a decreased papilloma yield on subsequent promotion with croton oil.Acknowledgment. The author thanks Mr M. Froscio for excellent technical assistance.This investigation was supported by the Australian Research Grants Committee, the Australian Tobacco Research Foundation and the University of Adelaide Anti-Cancer Foundation.     

Experimental coupling of crab (Carcinus maenas) second maxilla neural motor to an alternating current

Summary Movements of the crab gill bailer were entrained to an alternating current applied to the thoracic ganglion. There was little distortion of the muscle recruitment cycle, both absolute and relative coordination were observed, and the phase of the driven system in the driving cycle was a function of the difference between free running and driving frequencies.I am grateful to ProfessorK. Simkiss for providing facilities in the Department of Zoology, Reading University. Some of the equipment was provided by University of Otago Research Committee grant No. 37-097.     

Ammoniacal silver staining of normal and inflamed rat synovial membrane

Summary An ammoniacal silver technique was used to detect changes in histone profiles in normal rats and rats with adjuvant-induced arthritis. Under these conditions histone staining reactions change at times when synovial cells are becoming more metabolically active.Acknowledgments: Supported by Biomedical Research Development Grant No. ISO08RR09016-01 from the National Institutes of Health, by grants to both authors from the Marquette University Committee on Research and by Marquette University School of Dentistry.     

A rapid method for the fractionation of avian blood cell nuclei

Summary Red blood cell nuclei from avian anaemic blood have been fractionated by rate sedimentation on discontinous sucrose gradients into fractions which can be distinguished both by their RNA synthesizing ability and by their morphology as revealed by electron microscopy.Acknowledgment. We wish to thank H. Gitay for the electron micrographs. This work was supported by grants from the University of Cape Town Research Committee and the Council for Scientific and Industrial Research.     

The sensitive period for yellow phenocopy induction inDrosophila melanogaster

Summary Yellow phenocopies ofDrosophila melanogaster were produced by raising larvae on -DMT contaminated media. Using a survivorship test, the sensitive period for phenocopy induction was found to occur during the third larval instar of development, with increased survivorship at 1% -DMT compared with lower concentrations. It was also found that treatment with -DMT significantly slowed development. These findings are related to the relevant morphological and behavioral developmental pathways and to phenocopy induction.Publication No. 35 from the Evolutionary Genetics Laboratory, University of Auckland.Acknowledgments. We thank the New Zealand Entomology Society for a grant from their Anniversary Fund to R. D. Newcomb and the University Grants Committee, Research Grant No. 394.597 to D.M. Lambert.     

What distinguishes cosmopolitan and endemicDrosophila species?

Summary CosmopolitanDrosophila species can survive wide ecological tolerances measured by resistance to desiccation/temperature extremes compared with endemic rain forest species. This, rather than any genetic features, is important in helping to explain the widespread distributions of cosmopolitan species.We thank Dr Lee Ehrman for cultures ofD. paulistorum, and the Australian Research Grants Committee for financial support.     

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.     

On the location of the tetrapyrrole macrocycle of chlorophyll a in phospholipid vesicles and in hexadecane

Summary The state of chlorophyll a in phosphatidylcholine vesicles was examined. The results indicate that the chlorophylls are present in monomeric form. A kinetic study of chlorophyll reactions with K₂S₂O₈ and piperidine showed that these substances react with the porphyrin rings of pigments located on both vesicle faces, most probably within the polar headgroup region.Acknowledgments. This work was supported by the Research Committee and the Biophysics Research Group, University of Québec at Trois-Rivières.     

Effects of the optical isomers of 2-amino-3-fluoro-1-phenylpropane (monofluoroamphetamine) hydrochloride on uptake and release of dopamine in rat striatum in vitro

Summary The (+)- and (–)-isomers of the monofluorinated amphetamine 2-amino-3-fluoro-1-phenylpropane were prepared and compared for their ability to stimulate release and to inhibit reuptake of radiolabelled dopamine from rat striatal tissue in vitro. The (+)-isomer was much stronger than the (–)-isomer in both cases.Financial support for this project was supplied by the Medical Research Council of Canada, the Alberta Mental Health Research Fund and the Special Services and Research Committee, University of Alberta Hospital.Acknowledgments. Skilled technical assistance was provided by Ms L. Hiob. The authors also wish to thank Dr W.G. Dewhurst, Department of Psychiatry, and Dr D.F. LeGatt, for their advice and comments.