Inheritance of asymmetry inKrizousacorixa femorata (Guérin)

Krixousacorixa femorata (Guérin), a Mexican corixid, has symmetrical females and asymmetrical dextral or sinistral males. In studying the genetics of this species a sequence of experimental matings is described and the segregation ratios of the progenies analyzed. On the basis of these experiments a hypothesis, adequately explaining the data, is proposed.Exhypothesi the inheritance of the polymorphic characteristic of asymmetry depends upon the allelomorphic series of three genes,D, D ⁸, andd, of whichD (dextrality) is dominant toD ^s (sinistrality) which in turn is dominant tod (dextrality). The intermediate member of the series is lethal as a homozygote.A portion of the dissertation submitted in partial fulfillment of the requirements for the doctorate at Cambridge University. I wish to thank Professors SirRonald Fisher of Cambridge University andG. E. Hutchinson of Yale University for their kind help.     

The protein–polysaccharide complex of bovine nasal cartilage. Studies on the protein core

1. Chondromucoprotein from bovine nasal cartilage was purified by cetylpyridinium chloride or by bismuth nitrate in acetone. 2. Amino acid compositions of crude and purified preparations were compared and few differences were found, in spite of the decrease in protein content on purification. 3. Amino acid analysis of bismuth-purified material revealed the existence of four groups of amino acids. Within each group, the amino acids were present in approximately equimolar concentrations. 4. Amino end-group assay on the same material showed six alpha-DNP derivatives. 5. A molecular weight of 6.3x10(5) for the protein-polysaccharide complex was calculated from the latter analysis.     

Fluoride metabolism in Acacia georginae Gidyea

1. The metabolism of fluoride in seedlings and small plants of Acacia georginae has been studied with the idea of finding the conditions under which the plant makes fluoroacetate in the laboratory. 2. Individual seedlings vary in the extent to which they take up fluoride and convert it into a form other than inorganic which is here called `organic' fluoride, F(org.). The differences between the toxicity of A. georginae Gidyea trees may therefore be genetic in origin. 3. The uptake of fluoride from solutions 0·525–1·05mm (10–20p.p.m.) was not large. In 1–4 days it reached 8 p.p.m. in the aerial parts and 16 p.p.m. in the roots. Unlike the distribution of the halogen in grass, total fluoride was greater than inorganic fluoride. It was almost a rule that more `organic' fluoride was present in the roots than in the aerial parts. 4. With higher concentrations of fluoride 10·5–15·75mm (200–300p.p.m.) much larger amounts of fluoride were taken up, especially by the roots, and much more apparent organic fluoride was formed. 5. pH had a large influence upon the intake, this being lowest at an initial pH8·4 and highest at pH4·0. The pH outside this range was not investigated.     

Fundamentals of an applied ecosystem research project in the Wadden Sea of Schleswig-Holstein

The aims, content, and organisatory structure of a proposed interdisciplinary ecosystem research project in the Wadden Sea of Schleswig-Holstein (W. Germany) are briefly presented. The project will include research on both fundamental as well as applied aspects of the Wadden Sea ecosystems and their interaction with local human activities. In contrast to most of the other completed or currently running ecosystem research projects on tidal coasts, a considerable part of the scientific work will also deal with aspects of ecosystem management and protection of the various marine and semiterrestrial habitats of the Wadden Sea. Considerable attention is paid to theoretical and methodological aspects of research on ecosystems and landscape units. In particular, the adoption of a hierarchical view of complex biological and environmental systems is recommended. Presented at the VI International Wadden Sea Symposium (Biologische Anstalt Helgoland, Wattenmeerstation Sylt, D-2282 List, FRG, 1–4 November 1988)