Constitutive heterochromatin and nucleolus organizer region in the knifefish,Apteronotus albifrons (Pisces,Apteronotidae)

Summary The C-banding and silver staining of the chromosomes of the knifefishApteronotus albifrons (2n=24), demonstrated the presence of constitutive heterochromatin in the centromeric region of every chromosome, except pair 4, where the entire long arm was darkly stained, the silver stain positive nucleolus organizer region (NOR) being embedded in it.The authors are grateful to Dr Sen Pathak (University of Texas System Cancer Center at Houston, Texas, USA) and Dr Yatiyo Yassuda (Universidade de São Paulo, São Paulo, Brasil) for their suggestions. This study was supported in part by grants of the Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq).     

Coronary perfusion pressure as a determinant of ventricular performance

Summary The results observed in this work support the view that coronary perfusion pressure affects ventricular performance independently of metabolic effects; a mechanism operating in beat-to-beat regulation is proposed.This work was carried out during the tenure of grants in aid from the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP médicas 78/1392) and from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq 2222, 1608/78).     

Proteolytic enzymes in theRhodnius prolixus midgut

Summary Sequential chromatographic fractionation ofRhodnius prolixus midgut homogenate yielded only one endopeptidase, but revealed the presence of carboxypeptidase-A and B-like enzymes, di- and tripeptidases, as well as aminopeptidase activities.Work subsidized by FINEP and CNPq, Rio and FAPESP, São paulo.     

Electrophoretic variation in esterases in 3 wild-type and respective mutant strains ofAspergillus flavus

Summary Wild-type strains and auxotrophic mutants ofAspergillus flavus, differing regarding aflatoxin production, were tested for esterases isozymes. Esterases variation was found in all strains used, and a possible correlation between the pattern of esterase bands and aflatoxin production is suggested.Acknowledgment. The authors are thankful to the National Council for the development of Science and Technology (CNPq) and Assistance to Research for São Paulo State (FAPESP) for financial assistance.     

Occurrence of a new type of mosaicism inApis mellifera

Summary A mixture of tissue with male and female olfactory plates (sensilla placodea) was observed in the antennal segments number 8, 9 and 10 of a gynandromorphic honeybee obtained by radiation from a Co⁶⁰ source.Work carried out with financial help of Fundação de Amparo A Pesquisa do Estado de São Paulo, Brazil.     

Vesicular inclusions in the nuclei of epithelial cells of Malpighian tubes of the hemipteran,Panstrongylus megistus

Summary Vesicular inclusions observed in Malpighian tubes of hemipterans have been associated with a virus-like infection rather than a lysosomal-type activity, which is the case of the identical cytoplasmic structures.This study was supported by a grant (75/907) of the Fundação de Amparo à Pesquisa do Estado de São Paulo. The authors are indebted to Dr E. O. Rocha-e-Silva for generously providing them with the insect specimens.     

An alternative decomplementation method for the measurement of the survival of human erythrocytes transfused into rats

Summary An alternative technique for measuring the survival of⁵¹Cr-labelled human erythrocytes transfused into rats is described, in which aggregated human gamma-globulin is substituted for cobra venom factor as a decomplementing agent.Acknowledgments. This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo and Conselho Nacional de Desenvolvimento Cientifico e Tecnológico.     

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.     

Anticomplementary fraction from the poisonous secretion of the paratoid gland of the toad (Bufo marinus paracnemis Lutz)

Summary Fractionation of the poisonous secretion of the toadBufo marinus paracnemis Lutz, by dialysis and chromatography on QAE-Sephadex, led to the isolation of a fraction which was adsorbed to the ion exchanger. This fraction, when incubated with human serum, yielded an anticomplementary effect that was evaluated by measuring the kinetics of lytic activity on sensitized sheep red cells (classical pathway) and unsensitized rabbit cells (alternative pathway).We are very much indebted to Dr Lewis J. Greene for valuable discussions. Thanks are due to Dr Antonio C. Nero and Miss Ester G. Silva for their cooperation. This work was supported in part by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).     

Biological studies onPseudohypocera kerteszi (Phoridae,Diptera)

Summary 15 couples ofPseudohypocera kerteszi were introduced into individual tubes containing culture medium, maintained at 22–28°C and 45–55% relative humidity. The courtship and the behaviour of males and females before and after the copula are described for the first time; the number of eggs laid by each female during the oviposition period and the sexual rate in offspring were registered in each tube. The relative viability from egg to imago was determined in 8 of the 15 tubes.This study was made possible by a grant of the State of São Paulo Research Foundation (FAPESP).     

Aggressive behaviour induced by marihuana compounds and amphetamine in rats previously made dependent on morphine

Résumé Les rats soumis à la morphine ont été traités pendant la phase d'abstinence avec des injections i.p. d'amphéta mine et (–) ⁹-trans-tätrahydrocannabinol.

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With a fellowship from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP). We are very grateful to Prof.J. Ribeiro do Valle, Escola Paulista de Medicina, for the generous supply of THC.     

DNA and RNA content in diploid and tetraploid amphibians

Resumen En el anuro tetraploide naturalOdontophrynus americanus, el contenido de DNA es el doble que el determinado, bioquimicamente, en los especimens de la población diploide deO. americanus. Sin embargo el contenido de RNA de ejemplares de las dos poblaciones es aproximadamente igual. Aparentemente, mecanismos de regulación bloquean el esceso de material genético en el tetraploide.

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This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo, the Conselho Nacional de Pesquisas, the Fundo de Pesquisas do Instituto Butantan and the Rockefeller Foundation.     

Effect of gentamycin on insulin release and45Ca net uptake by isolated islets

Summary In isolated islets, gentamycin reduced both the⁴⁵Ca net uptake and insulin release induced by glucose, but failed to inhibit the insulin secretion provoked by the combination of Ba²⁺ and theophylline. This indicates that the inhibitory effect of gentamycin is due to a reduction of Ca²⁺ entry into B-cells instead of to a harmful effect upon the integrity of the effector system, responsible for the extrusion of the insulin containing granules.Supported by a Grant (No. 79/1872) from the São Paulo State Research Foundation (FAPESP), Brazil.     

Some metabolic disorders affecting the carotenoid-linked haemolymph proteins inRhynchosciara americana (Diptera,Sciaridae)

Summary Disorders in the carotenoid metabolism are proposed to explain the absence of the yellow and violet or only the violet carotenoid-linked proteins from the haemolymph of someR. americana larvae. The lack of only the yellow chromoprotein is considered to be due to a failure in the biosynthesis of its apoprotein.Supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) and Conselho Nacional de Pesquisas (CNP_q). W.R.T. and A.G. de B. are indebted to Prof.F. J. S. Lara for advice, encouragement and for laboratory facilities. We thank Mr.A. Malavasi for collecting larvae in nature, Mrs.R. M. Zanelato for larvae culture and MissI. L. Jorge for typing.     

Ultrastructural and histochemical studies on the mucous granules in the tube feet of the starfishEchinaster brasiliensis

Resumen Es estudiada la ultraestructure y la histochimica de gránulos de secreción de células glandulares mucosas del pié ambulacrario de la estrella de marEchinaster brasiliensis. Estos gránulos secretores tienen una organización distincta comparada con aqueles encuentrados en la estrella del marAsternia stellifera anteriormente estudiada. Así son organizados en forma de circolos concentricos en torno du un eixo.

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Acknowledgments. The authors wish to express their thanks to Mrs.Arlene Mayhugh for her valuable technical assistance. This work was, in part, supported by grants from the Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil.

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Pesquisadora-Conferencista do CNPq (TC 308-Proc. 9051/70).     

Effect of scorpion venom fromTityus serrulatus (Tityustoxin) on the acetylcholine release and fine structure of the nerve terminals

Zusammenfassung Nachweis, dass ein Giftstoff des südamerikanischen SkorpionsTityus serrulatus auch in vitro am isolierten Meerschweinchendarm zu stark erhöhtem Acetylcholinausstoss führt der bei Kalziumentzug und Blockade des Natriumeinstroms durch Tetrodotoxin blockiert werden kann. Elektronenoptisch sind im Mäusezwerchfellpräparat nur im präsynaptischen Gebiet pathologische Veränderungen zu sehen.

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This work was supported by a grant (Biol. No. 72/134) of the State of São Paulo Research Foundation.     

Increased vascular permeability induced in synovialis of the rat by histamine,serotonin and bradykinin

Résumé La perméabilité vasculaire de la membrane synoviale du rat est augmentée par l'histamine, la sérotonine et la bradykinine. Dans cette réaction la sérotonine est plus active que l'histamine et la bradykinine.

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L.P.B. is supported by a Medical Postgraduate Research Scholarship from the National Health and Medical Research Council of Australia.

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We are indebted to Associate ProfessorJ. Garcia-Lémé, University of São Paulo, Brazil, for advice.     

In vitro inactivation of the neurotoxic action of β-bungarotoxin by the marine natural product,manoalide

Summary The irreversible neurotoxic action of -bungarotoxin (-BuTx) can be prevented by preincubation of the toxin with manoalide, a non-steroidal anti-inflammatory agent. Manoalide was also found to inactivate purified phospholipase A₂ and thus prevent hydrolysis of phosphatidylcholine. PLA₂ is a component found in several neurotoxic venoms and is also a rate limiting enzyme important in phospholipid metabolism and prostaglandin synthesis in man.This work is a result of research sponsored in part by NOAA-Department of Commerce under Sea Grant No. NA80AA-D-00120 and the California State Resources Agency R/MP-21. The US Government is authorized to produce and distribute reprints for governmental purposes. A preliminary report of aspects of this work appeared in Fedn Proc.42 (1983) 374. We also acknowledge the technical assistance of Dan Rohrer. Dr George Taborski's advice and assistance during the course of this work is gratefully acknowledged.J. C. de Freitas is a post-doctoral fellow supported by Fundacao de Amparo à Pesquisa do Estado de São Paulo (81/0263-9) and Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (201.171/82), Brazil.     

Thyroxine administration and the uptake of amino acids by liver cell nucleolus,nucleus and cytoplasm,and by other cell types

Résumé L'administration de thyroxine cause une chute de l'incorporation de la phénylalanine-H³ et du tryptophane-H³ par divers organes, excepté le foie. Le cytoplasme et les noyaux des hépatocytes ont presenté une plus grande concentration de substance injectée.

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This investigation was supported by grants from Fundaçao de Amparo à Pesquisa do Estado de São Paulo, Rockefeller Foundation, and Conselho Nacional de Pesquisas.

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The help of Profs.L. C. U. Junqueira andC. P. Leblond as well as the technical assistance of MissE. Freymüller are acknowledged.     

Phylogenetic relationship of the Brasilian leptodactylid frog generaCraspedoglossa,Cycloramphus andZachaenus

Summary Based on immunological comparisons of the serum albumins ofCraspedoglossa andZachaenus with antisera to albumin of several species ofCycloramphus, it is concluded that morphological and biochemical evolutionary rates have not been comparable within the study group. Taken together, the morphological and biochemical information demonstrate that whileZachaenus is a genetic member of theCycloramphus lineage, it has attained generic status.This study was supported by NSF grant No. DEB78-23396, the Amazon Ecosystem Research Program, Smithsonian Institution, the Fluid Research Fund, Smithsonian Institution, and the Museu de Zoologia da Universidade de São Paulo.The authors gratefully acknowledge the following colleagues for their help in procuring frog samples: R.I. Crombie, M.C. Duchêne, F.I. McCullough, F.C. do Val and P.E. Vanzolini.