Abnormalities in the development and reproduction of Blattella germanica (L.) (Dictyoptera: Blattellidae) treated with insect growth regulators with juvenile hormone activity

Summary Laboratory populations of German cockroach reared on food treated with R-20458 (75 ppm) or Ro 20-3600 (3000 ppm) became completely sterile and eventually extinct. The hypertrophied oocytes had excessively laid chorion, and the hypertrophied accessory sex glands contained excessive amounts of protein.     

Occurrence of DDT and BHC residues in human milk in India

The presence of pesticide residue of DDT and of BHC were determined in 1979 in samples of milk from 75 lactating mothers from Punjab, within a week after delivery. DDT and BHC residues were found present in all 75 samples collected. Recovery of isomers of BHC and metabolites/isomers of p.p'-DDT from the spiked samples was above 80%. The mean level of DDT residue was 0.51 ppm, which is more than the level reported from the U.S., Canada, Europe and Australia, but less than the level found in Guatemala. BHC residues also were higher than those found in other countries, with the exception of Japan. DDT level of 0.5 ppm in milk represents an infant intake of 0.09 mg/kg/day, which is 18 times the acceptable daily intake (0.005 mg/kg/day) recommended by the WHO. Acceptable daily intake of BHC has not yet been established.     

Sex determining mechanisms: an evolutionary perspective

Theories on the evolution of sex determining mechanisms are reviewed for male and female heterogamety, environmental sex determination, and briefly, haplo-diploidy and hermaphroditism. Because of their discrete and well-defined nature, sex determining mechanisms lend themselves to three types of evolutionary questions: what variety occurs and might be expected but does not occur, how do changes occur from one mechanism to another, and why do certain changes occur? All three approaches were illustrated for these different sex determining mechanisms. A generality emerging from these studies is that, at the level of selection of the sex ratio, there are no intrinsic problems in evolving from one sex determining mechanism to another: straightforward transitions between different mechanisms exist under various conditions.     

Sex determining mechanisms: An evolutionary perspective

Summary Theories on the evolution of sex determining mechanisms are reviewed for male and female heterogamety, environmental sex determination, and briefly, haplo-diploidy and hermaphroditism. Because of their discrete and well-defined nature, sex determining mechanisms lend themselves to three types of evolutionary questions:what variety occurs and might be expected but does not occur,how do changes occur from one mechanism to another, andwhy do certain changes occur? All three approaches were illustrated for these different sex determining mechanisms. A generality emerging from these studies is that, at the level of selection on the sex ratio, there are no intrinsic problems in evolving from one sex determining mechanism to another: straightforward transitions between different mechanisms exist under various conditions.     

Chiral influence of sex pheromonal substances on responses of the male American cockroach

Summary In order to elucidate the roles of optical enantiomers of sex pheromonal substances of the American cockroach, behavioral assays with a single enantiomer and with mixtures of enantiomers of sex pheromone mimics were carried out. Inactive enantiomers [(–)-enantiomers] had no influence on the potency of enantiomers active as sex pheromones [(+)-enantiomers]. By analysis of the results from EAG recordings with single and mixed sample of the enantiomers, it was confirmed that (–)-enantiomers did not react with the sex pheromone receptors which are responsive to (+)-enantiomers.We acknowledge technical assistance from Miss R. Kimura.     

Inhibition of steroidogenic activity in the adrenal cortex of rats fed benzene hexachloride (hexachlorocyclohexane)

Summary Feeding various dosages of benzene hexachloride (100, 250, 750 and 1500 ppm) in the diet to weanling male albino rats for 90 days resulted in marked hypertrophy of the adrenals with large, vacuolated cells in the cortex at 750 and 1500 ppm. Accumulation of cholesterol-positive lipids and marked reduction in the activities of steroidogenic enzymes such as ⁵ 3 HSDH, 11 HSDH, G-6-PDH and SDH were seen using histochemical methods in the adrenal cortex of rats fed 750 and 1500 ppm. The results are suggestive of steroidogenic inhibition at 750 and 1500 ppm of dietary BHC while 100 and 250 ppm did not produce any discernible changes in the adrenal cortex.Acknowledgments. The authors thank Dr Muralidhara, H.P. Ramesh and K. Nanjundiah for their help and Prof. H.B. Devaraj Sarkar, Department of Zoology, University of Mysore, for providing us facilities for histochemical work. We are grateful to Sri C.P. Natarajan, for his keen interest in this investigation.     

Superoxide dismutase activity in the Spanish population

Superoxide dismutase is an enzyme that catalyzes the dismutation of superoxide radicals to hydrogen peroxide and molecular oxygen. This superoxide radical is produced by all aerobic cells as a normal metabolic intermediate of molecular oxygen, and is dangerous for the cell because it induces the inactivation of various enzymes, lipid peroxidation and mutations. Superoxide dismutase can therefore be considered as a protective enzyme. The purpose of this work was to determine the level of superoxide dismutase activity in the Spanish population, and to study the factors that influence this activity. The superoxide dismutase activity of 2397 individuals was determined using the method described by Minami and Yoshikawa. The superoxide dismutase activity level in the adult Spanish population was found to be 4.16 +/- 0.89 Units/ml of blood. No significant variations with respect to sex were detected. But it was observed that the superoxide dismutase activity level was 9% higher in the young urban Spanish population.     

Superoxide dismutase activity in the Spanish population

Summary Superoxide dismutase is an enzyme that catalyzes the dismutation of superoxide radicals to hydrogen peroxide and molecular oxygen. This superoxide radical is produced by all aerobic cells as a normal metabolic intermediate of molecular oxygen, and is dangerous for the cell because it induces the inactivation of various enzymes, lipid peroxidation and mutations. Superoxide dismutase can therefore be considered as a protective enzyme. The purpose of this work was to determine the level of superoxide dismutase activity in the Spanish population, and to study the factors that influence this activity. The superoxide dismutase activity of 2397 individuals was determined using the method described by Minami and Yoshikawa. The superoxide dismutase activity level in the adult Spanish population was found to be 4.16±0.89 Units/ml of blood. No significant variations with respect to sex were detected. But it was observed that the superoxide dismutase activity level was 9% higher in the young urban Spanish population.     

A method to collect cervical smears from small breeds of monkeys

Summary A simple method is described to collect cervical smears and to have a clear view of cervix for small breed of monkeys. This method was found useful to collect adequate cytology smears with good preservation of cellular morphology.     

A method to collect cervical smears from small breeds of monkeys.

A simple method is described to collect cervical smears and to have a clear view of cervix for small breed of monkeys. This method was found useful to collect adequate cytology smears with good preservation of cellular morphology.     

A new quaternary ammonium compound with plant growth regulatory activity

Summary Of several quaternary ammonium derivatives tested, 1-allyl-1-(3,7-dimethyloctyl)piperidinium bromide showed the best growth-retarding activity. OnChrysanthemum morifolium the growth retardation obtained with a single application of 100–200 ppm compared favourably with that obtained from 2–3 applications of 3400 ppm of N-dimethylaminosuccinamic acid (daminozide).     

The effect of gibberellic acid treatment on the alkaloid content of matureIpomoea violacea L. Seeds

Résumé Une étude sur des plantesIpomoea violacea (L.) dans une serre a démontré qu'un traitement prolongé de 500 ppm d'acide gibbérellique pendant 9 semaines a réduit le contenu d'alkaloïdes des graines de la plante. Un traitement semblable de 100 ppm et un court traitement de 500 ppm a produit très peu d'effets.     

On the use of phosphamidon for eradication of fresh water fish predators

Zusammenfassung Laboratoriumsexperimente mit Phosphamidon ergeben eine günstige kritische Dosisempfindlichkeit für Labeo-Karpfen (150–250 ppm). Es gelingt so leicht, Wasserinsekten (2–10 ppm) und Raubfischstadien (20–125 ppm) aus den Frischwasserreservoiren zu eliminieren.

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Prepared and sold under the name of Dimecron 100 by Ciba Basel, (Switzerland).     

Changes in the T4/T3 molar ratio following thyrotropin releasing hormone injection in cattle.

The injection of thyrotropin releasing hormone into cattle resulted in a rapid decrease in the T4/T3 molar ratio. 2 breeds of cattle, Shorthorn and Africander Cross were studied. The decrease in the T4/T3 molar ratio was significantly greater in the Shorthorn breed. It is concluded that acute stimulation of the thyroid gland with TRH results in enhanced release of both T3 and T4 and that T3 is discharged more rapidly than T4.     

The effect of locality,breed and previous tick experience on seasonal changes in the resistance of cattle toBoophilus microplus (Ixodoidea: Ixodidae)

Summary A seasonal cycle in the expression of resistance to the tickBoophilus microplus occurs in cattle in central and southeastern Queensland, Australia. This is due to a seasonal fluctuation in the capacity of cattle to mount an effective immune response against the parasitic tick and is manifest as a waning of the expression of resistance in autumn and early winter which occurs irrespective of breed or the nutritional state of the cattle.     

Somatic chromosomes of black-headed oriole,Oriolus xanthornus (Linn.): A probable case of translocation heterozygosity

Summary 2n=80. There are 7 pairs of macrochromosomes in the male karyotype. In 2 females, besides the sex chromosomes, chromosome 3 and the largest microchromosome are unpaired and there is an additional large unpaired macrochromosome. This aberrant karyotype is best interpreted in terms of a reciprocal translocation heterozygosity, in all likelihood, at the population level.Acknowledgment. We thank Prof. U.S. Srivastava, Zoology Department, Allahabad University, for providing facilities. Financial assistance from CSIR, India in the form of a Senior Research Fellowship to one of us (H.A.A.) is thankfully acknowledged.     

Über Quecksilberspuren in Graphiten

Summary An investigation of 104 natural graphites shows in most of the samples a content <1 ppm mercury (Hg). An emissionspectrochemical method was used by the doubleare fromL. H. Ahrens. There are samples in the mine-ralogical collections with contents >10 ppm Hg, if metallic mercury is present in these collections.     

Amphibian sex determination and sex reversal

Amphibians employ a genetic mechanism of sex determination, according to all available information on sex chromosomes or breeding tests. Sex reversal allows breeding tests to establish which sex is heterogametic and provides an indication of the mechanism of sex determination. Cases of spontaneous and experimental sex reversal (by temperature, hormones or surgery) are reviewed and illustrated by previously unpublished studies on crested newts. These newts respond conventionally to temperature and hormone treatment but provide anomalous results from breeding tests. It is suggested that both the evolution from temperature dependency to a genetic switch and from ZZ/ZW to XX/XY are superimposed on a generally uniform mechanism of sex determination in all vertebrates.     

Karyotype and chromosome banding in the reed frog Hyperolius viridiflavus ommatostictus (Amphibia, Anura, Hyperoliidae)

C-banding and mithramycin staining were used to characterize the karyotypes of 10 specimens of the African reed frog Hyperolius viridiflavus ommatostictus from Tanzania. The diploid chromosome number is 2n = 24. Although no heteromorphic sex chromosomes were present in the mitotic karyotypes, in many diakineses of male meiosis one or two bivalents exhibited an end-to-end arrangement. In the laboratory 7 out of 24 females changed sex spontaneously. This indicates that an XY/XX system of sex determination operates in H. viridiflavus ommatostictus.     

Action of N-butylnorsympathone on the effects of cardioaccelerator nerve stimulation in the dog]

In Dogs anaesthetized with pentobarbital (30 mg . kg-1), N-butylnorsympathone (20 mg . kg-1 i.v.) reduced the bradycardia induced by stimulating the cardiac nerve (1, 2, 5, 10 Hz). Phentolamine (1 mg . kg-1 i.v.) or yohimbine (0.3 mg . kg-1 i.v.), two potent alpha-adrenoceptor blocking agents known to block presynaptic alpha-adrenoceptor induced a recovery of the effect of cardiac nerve stimulation. Prazosine (0.050 mg . kg-1 i.v.) an alpha-adrenoceptor blocking agent known to be ineffective on presynaptic alpha-adrenoceptors did not induce a recovery. However neither phentolamine or yohimbine were able to prevent the effects of N-butylnorsympathone. Neither haloperidol (0.050 to 2 mg . kg-1 i.v.) or pimozide (0.20 to 1 mg . kg-1 i.v.) induced a recovery or prevented the effects of N-butylnorsympathone. These results suggest that N-butylnorsympathone may stimulate presynaptic receptors which do not resemble classical presynaptic alpha-adrenoceptors or dopamine receptors.