Chymotrypsin gene expression during the intermolt cycle in the shrimpPenaeus vannamei (Crustacea; Decapoda)

InPenaeus vannamei, chymotrypsin is present as two isoenzymes in the hepatopancreas. The enzyme has been localized in F-cells by immunocytochemistry using a specific antibody. By in situ hybridization, with a 510 pb cDNA probe encoding for the first 170 amino acids of the shrimp chymotrypsin, mRNA was localized in the same cells. Gene expression was followed during the intermolt cycle by measuring changes in specific activity in crude extracts, and by the estimation of mRNA levels by Northern blots using the same probe. The increase in specific activity in premolt is preceded in early premolt by an increase in the amount of chymotrypsin mRNA. A second increase is observed in postmolt, suggesting a different mode of regulation of gene expression.     

Electrophysiological characteristics ofBombyx mori L. ventral nerve cord (effect of sodium and potassium on the membrane potential)

Summary Na⁺ and K⁺ effects on the resting cellular membrane potential of desheathed ganglia of theBombyx mori L. ventral nerve cord have been studied. The cells are depolarized by high concentrations of external potassium ions in the same way as in vertebrates, mollusca and crustacean cells. The possibility that the behaviour of the resting potential is not only influenced by the potassium equilibrium potential, but also by the conductances to other ions, is discussed.The authors are indebted to Prof V. Capraro, Drs B. Giordana and F. Sacchi for helpful comments and criticism.     

Hemolymph proteins in an ascitic condition,induced by lethal1(3)gl tumorous tissue inDrosophila hydei

Summary Drosophila hydei larvae homozygous for the gene1(3)gl may survive to the age of 3 weeks, become bloated and be incapable of metamorphosis. Wild-type flies after the injection of a fragment of the1(3)gl disc, which has been previously culture in vivo for 40–500 days, also become bloated (ascitic reaction). In the hemolymph of both the advanced1(3)gl larvae and ascitic adult hosts the accumulation of a specific protein is observed.Acknowledgments. This work was supported by the Swiss National Science Foundation under Grant No.3.792-0.76 and the Georges und Antoine Claraz-Schenkung. We thank Prof. H. Gloor, University of Geneva, and Prof. P.S. Chen, University of Zürich, for advice and criticism.     

Experimental gynogenesis provides evidence of hybridogenetic reproduction in theRana esculenta complex

Summary The gynogenetic offspring of the hybrid frogRana esculenta (R. ridibunda x R. lessonae) are exclusively of theridibunda type. This is due to the premeiotic exclusion of thelessonae genome from the hybrid's germ cells.Acknowledgments. Prof. M. Fischberg, Genève, and Prof. P. Vogel, Lausanne, provided laboratory facilities. This research was supported by the Swiss National Science Foundation, grants 3.221-0.73 and 3.644-0.75.     

Rana esculenta complex: An experimental analysis of lethality and hybridogenesis

Summary Experiments designed to analyze the lethality and hybridogenesis in the European green frog complex have yielded the following results: 1. As a rule the inter-se cross ofRana esculenta is lethal, but several crosses have produced fully viable progeny. The frequency of such break-through crosses appears to be related to parental population structure. 2. Parabiotic joining of lethal to viable embryos indicates that manifestation of the lethal effect is autonomous. There is, however, a 16–18% increase in the life span of the lethal partner. 3. Studies of LDH isozyme patterns revealed that thelessonae-specific alleles coding for the B^a and B^c subunits can be passed to the F₁ progeny from a parental female or male of theesculenta phenotype. This demonstrates that there is no total elimination of thelessonae genome in theesculenta germ cells. 4. Immunologically, offspring from the inter-se cross ofR. esculenta show a closer relationship to theridibunda than to theesculenta phenotype. Variations of antigenic protein patterns suggest the possibility of chromosomal recombination betweenlessonae andridibunda in theesculenta hybrid. These results are confirmed by two-dimensional electrophoretic analysis of proteins in the oocytes of the three frog phenotypes.This work was supported by grants from the Swiss National Science Foundation and the Georges and Antoine Claraz Schenkung.     

Temporal and spatial distribution of phosphoglucomutase (PGM) polymorphism in natural populations ofDrosophila melanogaster

Summary Drosophila melanogaster adults were collected for several years in various localities of Italy. The frequencies of thePgm electrophoretic alleles were determined and the similarity of the configuration of allelic frequencies observed. It was concluded that the PGM electrophoretic polymorphism could be maintained by random genetic drift in the natural populations studied only if the effective breeding size (N _e ) during the bottle-neck period is about 5000.I am grateful to Prof. D. Sperlich and Prof. W. Seyffert for their kind hospitality during my sojourn as Research Fellow of the Alexander von Humboldt Foundation in the Institute of Biology II at the University of Tübingen (FRG) where the final version of this paper has been done. The technical assistance of Mr A. Micheli is also acknowledged.     

Myosin heavy chains in fast skeletal muscle of chick embryo

Summary The peptide map obtained by electrophoresis after digestion of purified myosin heavy chains from pectoralis muscle of embryonic chicken with theStaphylococcus aureus V8 protease, produces a peptide pattern very similar but not identical to that of adult fast myosin. In fact, some components that are present in a small amount in the map of slow adult myosin are visible in the embryonic pattern.Acknowledgments. I wish to acknowledge the enthusiastic encouragement of Dr Ugo Carraro and the help of Prof. Stefano Schiaffino's group and of Dr Marcello Cantini for embryonic tissue isolation. The skillful technical assistance of Mr Silvio Belluco is also gratefully acknowledged. This work was supported in part by a grant of Muscular Dystrophy Association of America to Prof. Massimiliano Aloisi.     

Optic lobe neurosecretory cells of an Indian spiderCryptophora sp. (Areinidae)

Summary In all the 3 pairs of optic lobes ofCryptophora sp. there are small groups of monopolar PF^– neurosecretory cells which take on a green colour by PF technique and red by Azan. Their function is unknown, but they may be involved with photoperiodically controlled activity rhythms.We wish to express our thanks to Prof. U.S. Srivastava for providing working facilities and valuable suggestions.     

Experiments on sexual isolation between Chilean and European strains ofDrosophila subobscura

Summary Males and females of Chilean strains ofDrosophila subobscura exhibit a pronounced tendency toward homogamic mating. This tendency shows a clear relation to the distance between the geographic localities from which the respective strains came. Nevertheless, when the Chilean flies are confronted with European strains, the ethological isolation is observed in some cases but not in others, depending on the geographic origin of the strains.Acknowledgments. This work has been partially supported by grants from the Univ. of Chile (Project B 729-8345) and PNUD/UNESCO (RLA 78/024). We are most grateful to Prof. D. Sperlich of the University of Tübingen who provided theD. subobscura strains from Tübingen and Sicily, and Prof. A. Prevosti from the University of Barcelona and R. de Frutos from the University of Valencia who provided the strains of Mallorca and Almería. We are finally obliged to Mr E. Zárate for his technical assistance.     

Isomériecis-trans des ménaquinones et oxydations phosphorylantes dans les extraits deMycobacterium phlei

Summary Incubation ofM. phlei washed cells with [¹⁴C³H₃]-l-methionine led to [2-¹⁴C³H₃] dihydromena-quinone-9 with an isotope ratio identical to that of methionine. Chromatography of the doubly labelled quinone indicated, despite a pronounced isotope effect, that bothcis andtrans isomers had the same isotope ratio. This result eliminates any possibility of hydrogen exchange in the 2-methyl group of menaquinones during oxydative phosphorylation, even in thecis isomer. Furthermore, it is confirmed that this compound is certainly formed from natural or synthetic menaquinones during isolation or incubation periods by the effect of daylight irradiation.     

Localization of wheat germ agglutinin receptor sites on yeast cells by scanning electron microscopy

Summary WGA receptor sites on the surface ofSaccharomyces cerevisiae cells pretreated with an - mannanase were localized by gold granules labelled with WGA. The receptor sites were found on the bud scars, the mother cell-bud junction (chitin) and the bud, but not on the mother cell.Acknowledgment. We thank Prof.C. E. Ballou for supplying theArthrobacter strain GJM-1 and MrsM. Weber for the photographic work.     

Selection for class IIMhc heterozygosity by parasites in subterranean mole rats

Mhc organization and polymorphism have previously been studied²⁶ in the four chromosomal species of theSpalax ehrenbergi superspecies in Israel, serologically, and at the DNA, RFLP and sequence levels of class I and class II genes. Here we demonstrate that the observed heterozygosity ofMhc class II genesP₁ with 11 alleles, andQ, with at least 14 alleles, is positively and significantly correlated with infectivities of ectoparasites (gamasid mites)¹⁷ and endoparasites (helminths)¹⁸.Mhc heterozygosity is highest in the most infected area, which is in the most humid-warm region of the superspecies range, or where two zoogeographic regions overlap. We conclude that the evolutionary forces responsible for theMhc class II two-gene polymorphisms include selection for increased heterozygosity as a defense strategy against ecto- and endoparasite infections.     

Genetic variation at the alcohol dehydrogenase locus inDrosophila melanogaster: A third ubiquitous allele

Summary A 3rd allele at theAdh locus,Adh ^FCh.D., has been found at polymorphic frequencies in natural populations ofD. melanogaster. The ADH-FChD enzyme has properties distinct from those of the 2 more common forms of ADH. TheAdh polymorphism should now be analyzed as a triallelic system.     

Der Einfluss von Adrenalin auf das Verhalten des zellulären Kalziums während der K-Depolarisation des Herzmuskels von Meerschweinchen

Summary The effect of adrenaline on the cellular calcium exchange during the K-depolarization of myocardium was studied in isolated left auricles of guinea-pigs by means of the⁴⁵Ca. Increasing the extracellular K-concentration from 2.7–30 mM without corresponding reduction in sodium concentration results in a depression of contraction strength of the myocardium when current is applied. The depression is immediately reversible by using adrenaline. This was associated with a significant increase of the⁴⁵Ca exchange.     

Autoradiographic studies on RNA synthesis and transport in the Salivary gland ofLygaeus sp. (Hemiptera-Lygaeidae)

Summary Autoradiographic studies using³H-uridine in the salivary gland of adultLygaeus sp. were carried out. The gland cell nuclei, particularly the multiple nucleoli, are the sites of incorporation of the label exhibiting RNA synthesis. The labelled molecules (RNA) are transported to the cell cytoplasm and then into the gland lumen in which no turnover of the radioactivity is observed.I am grateful to my teacher, Prof. P. S. Ramamurty, School of Life Sciences, University of Hyderabad, for his constant inspiration. Grateful acknowledgement is made to Prof. J. P. Thapliyal, Dept of Zoology, B. H. U. for encouragement and to Dr Om Prakash, Dept of Biochemistry, B. H. U. for his valuable criticism.     

Activation and specificity of alkaline phosphatase of a mineralizing collagen-rich system

Summary Alkaline phosphatase from tibia tendon ofMeleagris gallopavo L. was highly purified. The enzyme activation by different ions was measured. Mg²⁺ showed a high activation with a broader spectrum of phosphomonoester hydrolization. The in vivo Mg²⁺ concentration was an optimum for in vitro activation.Dedicated to Prof. Dr. G. Pfefferkorn on the occasion of his 65^th birthday.We thank Deutsche Forschungsgemeinschaft for support.     

Prevention of estrogenic inhibition of adrenal 686-1686-1686-1686-2686-2686-2in rats

Summary The urinary protein _2u stimulates adrenal ⁵-3 dehydrogenase activity and prevents adrenal enlargement in estrogen-treated adult male rats.Acknowledgements. Dehydroepiandrosterone used in this study was donated by Organon(India) Ltd, Calcutta. This work received financial support from University Grants' Commission, New Delhi. The author's thanks are due to Prof. A. K. Maiti and Prof. C. Deb, Department of Physiology, Calcutta University, for their constant encouragement.     

Dominance for enzyme activity inDrosophila melanogaster

Summary A regulatory element tightly linked to theGpdh locus inDrosophila melanogaster has been isolated from a natural population. Flies homozygous for second chromosomes bearing the element,H31, have half the GPDH activity of normal homozygotes. Heterozygotes betweenH31 andF orS alleles exhibit dominance in GPDH activity. Heterozygotes betweenH31, F orS andDf(2L) GdhA have half the diploid level. The contribution of theS allele to the activity inS/H31 heterozygotes is more than four times that ofH31. The regulatory element distinguishingH31 is tightly linked to theGpdh ⁺ locus.     

A reappraisal of the hormonal regulation of larval fat body histolysis in femaleDrosophila melanogaster

The histolysis of larval fat body cells in adult femaleDrosophila melanogaster was examined in wild type and mutant animals. The fat body cells of wild type (Canton-S),apterous ^56f homozygotes,apterous ^78jts homozygotes and heterozygotes,apterous ⁴/+, ecdysoneless¹ homozygotes and heterozygotes all underwent histolysis normally during the 72 h following adult eclosion. Only in the case ofap ⁴/ap⁴ adults did the cells fail to histolyze normally. The fat body cells of both diapausing and non-diapausing wild type females underwent histolysis at the same rate. Attempts to demonstrate histolysis in vitro were unsuccessful, even in the presence of juvenile hormones (JHs), larval ring glands, or adult ovaries. In all strains other than theap ⁴ homozygotes, a significant proportion of larval fat body cells were dead at any time while theap ⁴/ap⁴ animals, almost all cells remained viable. It is postulated that fat body cell lysis following eclosion is not a JH-mediated event, but is elicited by an as yet unidentified factor(s), possibly originating in the ovary.