Genetic basis of susceptibility for development of neoplasms following treatment with N-methyl-N-nitrosourea (MNU) or X-rays in the platyfish/swordtail system

Summary Specific genotypes of the xiphophorine fish develop neoplasms following treatment with N-methyl-N-nitrosourea or X-rays. Several of these neoplasms can be related to the presence of specific chromosomes. The implications of these findings are discussed.Supported by Deutsche Forschungsgemeinschaft through Sonderforschungsbereich 103 Zellenergetik und Zelldifferenzierung, Marburg (projects C 9 and C 10), and by Justus-Liebig-Universität Giessen. We are indebted to Prof. K. Frese, Veterinär-Pathologisches Institut, Giessen and Dr H. D. Mennel, Pathologisches Institut, Freiburg, for their help in the classification of neoplasms. We furthermore thank K. Klinke for breeding the fish. Dedicated to Prof. C. Kosswig on the occasion of his 75^th birthday.The paper contains parts of the dissertations of S. Abdo, J. Haas and G. Kollinger.supported by the Egypt ministry of education.     

Increased susceptibility ofTrypanosoma lewisi infected,or decomplemented rats toSalmonella typhimurium

Summary Rats infected withTrypanosoma lewisi or decomplemented by injection of cobra venom factor or complement activating factor of trypanosomes were found to be more susceptible to infection withSalmonella typhimurium. Decomplemented rats subsequently infected withT. lewisi developed higher blood parasitemia than did normalT. lewisi infected rats.This project is supported by the National Research Council of Canada grant A 0068 and a grant from the International Development Research Center.     

Chromosome variations inXenopsylla astia Rothschild, 1911 (Siphonaptera). A preliminary report

Summary 2 populations of rat fleas,Xenopsylla astia, collected from (A) Bombay and (B) Trivandrum, were found to differ in chromosome number as follows; (A) 2n=10 in both sexes; (B) 2n=18 (male) and 20 (female). Preliminary observations have further shown that the 2 populations differ in certain morphological characters and that their reciprocal hybrids are sterile in the male and partially sterile in the female sex.Acknowledgments. We wish to express our deepest gratitude to Dr Robert E. Lewis, Professor of Entomology, Iowa State University, USA, for confirming our identification of the 2 samples of rat fleas. We are indebted to Dr N.R. Prabhoo, Reader in Zoology, University of Kerala, Trivandrum, for his advice and helpful suggestions. We are also indebted to Prof. K.M. Alexander, for encouragement and providing facilities. Financial help of the University Grants Commission, India, to one of us (C.T.) is also gratefully acknowledged.     

Striated inclusions and defective mitochondria in the restricted form of the ‘amycelial’ mutant ofNeurospora crassa

Summary The cytoplasm of the restrictive form of the amycelial mutant ofNeurospora crassa, growing on sucrosemedium, contains paracrystalline, microfilamentous inclusions and mitochondria with internal membranous whorls lacking in acetate-grown cultures.The support of the Fonds national suisse de la recherche scientifique is gratefully acknowledged.     

Structural differences of cone ‘oil-droplets’ in the light and dark adapted retina ofPoecilia reticulata P.

Summary The vast majority of oil-droplets in the dark and light-adapted retinal twin-cones ofPoecilia reticulata is of the matrix-type. In bright light (day light+overhead strip light) there occurs in some regions a very pronounced numerical change from matrix to cristate-type, whereas other regions remain unaffected. The functional significance of these differences is discussed.     

The effect ofγ-irradiation on soil enzyme stability

Summary Arylsulphatase, -1,3 glucanase, phosphatase and urease responded differently to -irradiation (5–50 Mrad) in air-dried and moist soils. In all instances phosphatase was the most stable. The variability between enzymes may be due to inherent biochemical and stuctural characteristics or to their location within the soil microenvironment.Supported by a grant from the NERC.     

Large-scale purification of hepatitis B surface antigen using affinity chromatography

Summary Large-scale purification of hepatitis B surface antigen, applicable to the preparation of potential vaccines for prevention of hepatitis B, is described. The method involves the following steps: precipitation of serum with polyethylene glycol 6000, affinity chromatography on concanavalin A-Sepharose and on -aminononyl-Sepharose, and isopycnic centrifugation.This study was supported by grant 09011 from the National Heart, Lung and Blood Institute. We thank Dr. B. Hollinger for testing HB_sAg samples by a complement fixation test.     

Mammalian spot test with moxnidazole, a 5-nitroimidazole

Moxnidazole [3-(5-nitrol-1-methyl-2-imidazolyl)-methyleneamino-5-morpholinomethyl-2-oxazolidinone, HCl], known to be mutagenic in microbial tests and Drosophila, induced genetic alterations in somatic cells of mice. Ethyl methanesulfonate (EMS) served as positive control.     

Seasonal variations in fat body metabolism of the green frog Rana esculenta (L.).

Rana esculenta (L.), kept under natural conditions, show almost constant body weights in the annual cycle. Fat body weight, however, has a distinct maximum in October decreasing continuously to a May minimum which is also evident in the fat body index. The triglyceride and protein contents show the same course. Suprisingly high amounts of glycogen are found, which reach a maximum in August.