Rhythmicity of aminotransferase in the cockroach,Periplaneta americana

Summary Aspartate (AAT) and alanine aminotransferase (AIAT) activities in nervous system and coxal leg muscle of the cockroach showed circadian variations with maximal activity around midnight, alternating with minimal activity at 12.00 noon of the solar day. The enhanced activity levels of the enzymes observed during night dark hours may be related to higher energy requirements during increased locomotor activity of the animals.We thank Prof. K. S. Swami, for providing facilities. The financial help rendered by UGC and CSIR, in the form of Junior (to SV) and Senior (to TPK) Research Fellowships is acknowledged.     

Role of vitamin B 12 in the incorporation of ribonucleosides into the DNA of various Periplaneta americana cell lines]

Hemocytes and non hemocytes in vitro cell lines from Periplaneta americana, have been tested for their ability to incorporate, in the presence of vitamin B 12, various nucleic acid precursors into their DNA. Evidence was shown for enhanced transformation of all ribonucleotides into deoxyribonucleotides in the presence of vitamin B 12. Moreover, in hemocyte cell lines, it was demonstrated that vitamin B 12 produced an activation of thymidine kinase activity.     

Nerve growth in cockroaches (Periplaneta americana) with rotated ganglia

Summary The axons of motorneurons in rotated cockroach ganglia grow into the limb opposite the one they normally innervate and appear to synapse with appropriate muscles. Apparently the classification of motorneurons is duplicated about the mid-line.I thankNan Cowan for her expert technical assistance.     

Absorption and excretion of benzpyrene in the cockroach (Periplaneta americana)

Résumé Le benzopyrène le pyrène et l'anthracène peuvent être révélés au moyen du spectrophotomètre dans les extraits de tissu des blattes (Periplaneta americana) nourries avec ces hydrocarbures; ils sont excrétés lorsqu'on interrompt l'alimentation.

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Supported by grant CA 01469-11 from the National Cancer Institute, Public Health Service.     

Neurosecretory control of Corpora allata activity in cockroach,Periplaneta americana L.

Summary The brain neurosecretory material is involved in the control of Corpora allata activity during post-embryonic development. A high concentration of neurosecretory material within the Corpora allata restrains the activity of the gland.     

Vital staining of neurosecretory material with acridine orange in the insect,Periplaneta americana

Résumé On expose une méthode rapide de la coloration vitale à l'acridine orange des produits de neurosécrétion dans le tissu nerveux des insectes. Irradiés avec la lumière bleue, tout les types connus de produits de neurosécrétions entrent en fluorescence en prenant une teinte métachromique rouge.

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I am indebted to Prof.B. Johnson for helpful suggestions and criticisms. This study was supported by a University of Tasmania Research Grant and the author has received financial support from I.C.I.A.N.Z. and University of Tasmania Post-Graduate Scholarships.     

Location of the sex pheromone in the American cockroach,Periplaneta americana (L.)

Zusammenfassung Das Vorkommen von Sexualpheromon wurde an dem Werbeverhalten von selektierten einzelnen Männchen getestet. Das Pheromon kommt in larvalen und adulten Insekten beiderlei Geschlechts vor, wird aber von geschlechtsreifen Weibchen in grösseren Mengen produziert. Es kommt hauptsächlich im Kopf vor und wird wahrscheinlich an Orten modifizierter Körperdecke abgesondert.     

Gnawing activity,dietary carbohydrate deficiency and oothecal production in the American cockroach (Periplaneta americana)

Summary The gnawing activity of adult female cockroaches was assessed by the dry weight loss of cotton fibre supplied to individual insects. In animals maintained on a carbohydrate-deficient diet the use of fibre was significantly less than in animals receiving a balanced diet. A comparison with controls showed that under both dietary regimes access to a fibre source did not significantly increase the mean, total number of oothecae produced.     

On the incorporation of S35-methionine in artificially activated sea urchin eggs

Riassunto Metionina-S³⁵ è stata incorporata in uova vergini diParacentrotus lividus. In queste l'isotopo si trova per la più gran parte nella frazione solubile in acido tricloracetico al 10%. Attivando le uova partenogeneticamente con acido butirrico si osserva una progressiva perdita di attività di questa frazione ed una rapida incorporazione nei mitocondri. L'andamento del fenomeno è del tutto identico a quello già descritto (Nakano eMonroy) nelle uova normalmente fecondate.

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Aided by a Grant from the Rockefeller Foundation.     

Synthesis of ecdyson-14C and ecdysterone-14C from cholesterol-14C in cockroaches (Periplaneta americana) without molting glands

Summary The synthesis of molting hormone of cockroaches of which the prothoracic glands had previously been extirpated was investigated after injection of cholesterol-¹⁴C. It could be proved by means of radio thin-layer chromatography of extracts that ecdysterone and in small amounts ecdysone, are synthesized in Periplaneta americana larvae without prothoracic glands. The results demonstrate that other tissues are also able to perform the molting hormone besides the molting gland itself.Supported by the Sächsische Akademie der Wissenschaften zu Leipzig.     

Increased rate of melanization in hemolymph of American cockroaches (Periplaneta americana) and house crickets (Acheta domesticus) intoxicated by insecticides

Treatment of house crickets and American cockroaches with any one of a variety of insecticides increased the rate of melanization in hemolymph incubated with diphenol substrates.