[3H]Formate incorporation into liver nucleic acids of chick. Relationships between orotic acid and vitamin B12

Riassunto E' stato studiato l'effetto dell'acido orotico sull'incorporazione di formiato-H³ nei nucleotidi liberi totali e negli acidi nucleici presenti nelle frazioni subcellulari del fegato di pulcino carente di B₁₂. La maggiore attività specifica dell'RNA nucleare e ribosomiale che si osserva negli animali trattati con acido orotico come in quelli trattati con vitamina B₁₂ potrebbe essere considerata l'espressione di una più elevata sintesi di RNA messaggero determinata da queste due sostanze.

---

---

This investigation was supported by a grant from Consiglio Nazionale delle Ricerche, Roma.     

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.     

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.

---

---

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

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.

---

---

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.     

Incorporation of [14C] amino acids into liver S-RNA of chick. Effect of orotic acid and vitamin B12

Riassunto La somministrazione dietetica di vitamina B₁₂ e di acido orotico determina un aumento della incorporazione dellal-serina C¹⁴ nello RNA solubile del fegato di pulcino carente di B₁₂, mentre non è in grado di influenzare quella dellal-leucina¹⁴C e dellal-metionina¹⁴C.     

Reserpine-induced depletion of gastric vitamin B12-binding proteins in the rat

Zusammenfassung Reserpin mobilisiert Histamin und den «Intrinsic factor» aus dem Rattenmagen. Eine trunkuläre Vagotomie hebt diese Wirkung von Reserpin auf. Reserpin hat keinen Effekt auf den «Intrinsic factor» des Magens von Maus, Hamster, Meerschweinchen und Kaninchen.

---

---

Supported by grants from the Swedish Medical Research Council (No. B71-14X-1007-05C and No. B71-19X-766-05C), the Medical Faculty of Lund, and Albert Pahlson's Foundation.     

The incorporation of carbon labelled precursors into the nucleic acids of various tissues in the intact rabbit

Résumé Les résultats expérimentaux montrent le degré d'incorporation du formate-¹⁴C, de l'adénine-8-¹⁴C et de la glycine-2-¹⁴C dans l'ADN et dans les ARN nucléaire et cytoplasmique de l'appendice, de la mlle osseuse, de la muqueuse intestinale, du rein, du foie, de la rate et du thymus du lapinin vivo.     

On the problem of linear incorporation of amino acids into cell protein

Summary Incorporation of amino acids into mammalian cell protein shows immediate linear kinetics when measured at intervals as small as 5 sec. Free amino acids equilibrate instantaneously across the cell membrane, acting as the precursor supply. Glycine, which does not initially show linear kinetics, may have a significant endogenous precursor supply, but this is not the acid-soluble pool.Acknowledgments. I thank the University of Aberdeen Medical Faculty Endowment Fund for support, and Mrs J. Robertson for technical assistance.     

Inhibition of thiamine synthesis by vitamin B12 in wild strains ofEscherichia coli

Zusammenfassung Zusatz von Vitamin B₁₂ in Kulturnährböden hemmt die Thiamin-Biosynthese von frisch isoliertenE.-coli-Stämmen. Diese Hemmung steht im Verhältnis zur zugesetzten Menge von Vitamin B₁₂.     

Uptake of labelled vitamin B12 and 4-iodophenylalanine in some tumours of mice

Zusammenfassung Die Verteilung von radioaktivem Vitamin B₁₂ und 4-Jodphenylalanin in tumortragenden Mäusen wurde ganztierautoradiographisch untersucht. Die grösste Aufnahme von B₁₂ wurde im weichen fibroblastischen Osteosarkom gefunden, während 4-Jodphenylalanin in einem Ehrlich-Ascites-Tumor aufgenommen wurde.     

Distribution of repetitive DNA sequences in the polytene chromosomes ofRhynchosciara americana

Summary The distribution of fast, intermediate and slow renaturing fractions ofRhynchosciara americana DNA was examined in the polytene salivary gland chromosomes by in situ hybridization. Heterochromatic areas readily hybridized but hybrid formation in the euchromatin depended more on the repetitiveness of the RNA probe.Supported by funds from the Fundação de Amparo à Pesquisa do Estado de São Paulo (Projecto BIOQ-FAPESP) and from The Research Foundation of The City University of New York.R.A. Eckhardt was a visiting professor under the Multinational Scientific and Technological Development Program of the Organization of American States.     

Effect of aflatoxin B1 on the in vitro incorporation of14C-acetate into human skin lipids

Zusammenfassung Aflatoxin B₁ hindert den in vitro Einbau des¹⁴C-Azetats in die Gesamtlipide, die freien Sterine, die Phospholipide und die Neutralfette der menschlichen Haut. Die Atmungsgeschwindigkeit der toxinbehandelten Gewebe wurde nicht beeinflusst.     

Effect of aflatoxin B1 on the incorporation of14C-acetate into cholesterol by rat liver

Résumé L'administration d'aflatoxine B₁ (2 et 5 mg/kg, i.p., 24 h avant le sacrifice) a résulté en un abaissement de 80% de l'incorporation du l-¹⁴C-acétate en cholestérol par des coupes de tissu de foie. Le même traitement n'a pas altéré l'activité des drug metabolizing enzymes au niveau des microsomes du foie.     

Effect of the growth-promoting alpha-globulin (GPAG) on in vitro incorporation of exogenous DNA into mammalian cells

Summary The uptake of exogenous³H-DNA by mammalian cells is increased in the presence of a specific serum protein complex — growth-promoting alpha-globulin (GPAG).³H-DNA is retained in the cell nucleus in a quantity 3 times higher than for control cultures without GPAG even after 47h of additional cultivation in the medium without³H-DNA.