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.     

Indirekte Regelmechanismen der Stoffwechselgröße von Fischen

Metabolic rate does not strictly follow changes of influencing parameters. O₂-consumption by fish is ordinarily said to be independent from O₂-pressure throughout a wide range. This constancy is probably the result of a regulation. The metabolic rate itself or an auxiliary mechanism “before” or “after” metabolism may be regulated. On the basis of vanDam's paper (1938) and our own experiments, the problem whether or not O₂-pressure in blood serves as a regulated auxiliary mechanism in order to maintain a certain metabolic constancy is discussed. The disadvantage of such a regulation would be the energy demand of increased ventilation and circulation as compensating mechanisms. In accordance with this assumption we have found a rise in O₂-consumption at a somewhat reduced O₂-pressure. Locomotory behaviour supports the constancy of metabolic rate; thus a contrary shift of the temperature preferendum after application of substances which influence metabolism has been found.     

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.     

Production of doubled haploid lines in frequencies sufficient for barley breeding programs

Winter barley (Hordeum vulgare L.) anthers were cultured on different liquid and on starch-solidified media. The optimal embryo and callus formation with different F₁-lines and the cv. Igri was obtained on a liquid medium with 20% Ficoll, 20 g/l maltose and barley starch. But the influence of the growth conditions of the donor plants and the genotypical differences are still enormous. The procedure has been optimized to such an extent that it can be used economically.     

The Ba fragment of complement factor B inhibits human B lymphocyte proliferation

Normal human B lymphocyte function is finely regulated by both positive and negative signals at each stage of activation, proliferation, and differentiation. Activation signals include antigen and surface Ig cross-linking agents such as anti-mu or anti-delta. Signals inducing proliferation include IL-2, high m.w.-B cell growth factor (BCGF), and low m.w.-BCGF. IL-2 as well as IL-6 and other partially characterized B cell differentiation factors can induce terminal differentiation of proliferating B cells into Ig-secreting plasma cells. Various C components have been described to regulate B cell function including Bb that enhances proliferation, C5a that enhances Ig production, and C3a that inhibits Ig production. In our study, we examined the ability of the factor B cleavage fragment Ba to influence human B cell function. Ba did not affect the activation of resting B cells but inhibited the proliferation of activated B cells stimulated with either high m.w.-BCGF or low m.w.-BCGF. The inhibition occurred with doses of Ba as low as 1 microgram/ml (29 nM). Ba was found to bind to activated human B lymphocytes in a saturable manner with an apparent K of approximately 25 nM and an apparent Bmax of 56,000 sites/cell. A peptide made of the carboxy terminal 10 amino acids of Ba (GHGPGEQQKR), was also found to inhibit growth factor induced proliferation of activated B cells but at an ID50 of approximately 5 microM. Finally, Ba was found to inhibit the terminal differentiation of Staphylococcus aweus Cowan-activated B cells stimulated with B cell differentiation factors but not Ig secretion by the partially differentiated EBV-transformed cell line SKW.6. Thus, concentrations of Ba achievable in vivo at sites of active inflammation were found to act on human B lymphocytes by inhibiting their proliferation. This may act to limit the immune response to a specific antigenic challenge.     

An abundant and ubiquitous homo-oligomeric ring-shaped ATPase particle related to the putative vesicle fusion proteins Sec18p and NSF.

We have discovered a ring-shaped particle of 12.5 nm diameter, 14.5S and apparent molecular weight of approximately 570,000 that displays 6-fold radial symmetry and is composed of a single kind of an acidic (pI approximately 5.5) polypeptide of Mr 97,000 (p97). Using antibodies to this protein we have detected its occurrence in a wide range of cells and tissues of diverse species from frog to man, including highly specialized cells such as mammalian erythrocytes and spermatozoa. In Xenopus laevis oocytes, the particle is found in both isolated nuclei and in manually enucleated ooplasms, which corresponds to immunofluorescence staining dispersed over both nucleoplasm and cytoplasm. The particle has a N-ethylmaleimide (NEM)-inhibitable Mg2(+)-ATPase activity, and its amino acid sequence, as deduced from cDNA clones, displays considerable homology to the mammalian NEM-sensitive fusion protein (NSF) and yeast Sec18p believed to be essential for vesicle fusion in secretory processes, indicating that these three proteins belong to the same multigene family.