Freeze tolerance in the frog,Rana sylvatica

Summary Wood frogs survive extracellular freezing at moderate subzero temperatures (–4°C) for at least 11 days. Freezing survival is aided by the accumulation of high concentrations of glucose as a cryoprotectant in blood and tissues. Glucose production was accompanied by a rapid decline in liver, but not muscle, glycogen levels suggesting that liver is the organ controlling cryoprotectant synthesis.Acknowledgments. This study was supported by grants to L.M.G. from the Kroc Foundation (Santa Ynez, California) and from the National Institute of Dental Research (Grant No. DE-03987). The authors wish to thank K. Yorko, M. Shakin, J. Finan and Mrs N. Manivannan for their technical and secretarial assistance.Acknowledgments. I thank Dr J. Ballantyne, Dr F. Schueler and I. McMurray for help with frog collections and Dr. W. Schmid, Dr J. Bogart and Dr F. Cook for helpful discussions. Supported by an N.S.E.R.C. operating grant and by a grant from the Atkinson Charitable Foundation.     

Infection of frog tadpoles (Amphibia) by insect parasitic nematodes (Rhabditida)

Summary Infective stage juveniles ofNeoaplectana carpocapsae (Steinernematidae) andHeterohabditis heliothidis (Heterorhabditidae) were able to penetrate through the alimentary tract of young tadpoles ofHyla regilla (Hylidae) andXenopus laevis (Pipidae) and enter the body cavity. Some infectives ofN. carpocapsae were able to release their symbiotic bacterium,Xenorhabdus nematophilus inside the host and in two cases, the nematodes developed into adult females before they perished. Tadpole mortality was associated with foreign bacteria entering the penetration holes made by the invading nematodes. The infective stage juveniles of both nematodes frequently encountered a host defense reaction upon reaching the tadpole's infective stage juveniles of both nematodes frequently encountered a host defense reaction upon reaching the tadpole's coelom.     

Genetic control of malate dehydrogenase inNicotiana suaveolens andN. glutinosa

Summary The study of malate dehydrogenase patterns in leaves ofNicotiana suaveolens, N. glutinosa and their interspecific hybrid has been carried out, in order to propose a model of its genetic control. Two possible explanations for the genetic control of malate dehydrogenase have been postulated forN. suaveolens, and at least two loci appear to be implicated in the control of this system inN. glutinosa.Acknowledgments. The authors thank Dr M. Pérez de la Vega for his valuable advice.     

Acetaldehyde oxidation inDrosophila null-mutants for alcohol dehydrogenase

Summary Aldehyde dehydrogenase (ALDH) activity is demonstrated in four strains ofD. melanogaster lacking active alcohol dehydrogenase (ADH-null mutants). In the four strains, ALDH activities are similar to those found in a wild strain. It is concluded that ADH-null flies are able to detoxify acetaldehyde. This finding is discussed in relation with the dual function of ADH proposed recently.This work was supported by a grant from the Medical Research Council of Canada (MRC 6920) to Dr F. Garcin.     

A reinvestigation of the chemistry of the Dufours gland of the formicine ant,Anoplolepis custodiens

The components of individual Dufours glands excised fromAnoplolepis custodiens workers were analysed by GC-MS. In addition to then-alkanes andn-alkenes previously reported² in these glands, primary alcohols (C₁₉-C₂₂), secondary alcohols (C₂₀-C₂₃), 2-ketones (C₂₀-C₂₃) and possibly carboxylate ethyl esters (C₁₉ and C₂₁) were identified as components of these glands. It seems possible that these high-boiling compounds are used by the workers in laying trails on the hot sandy surfaces of their characteristic habitat and in lining of the inner walls of nests, but no standard compounds have been available to us for any behavioral studies.     

Concordant change in mitochondrial and nuclear genes in a hybrid zone between two frog species (genusBombina)

Summary In contrast to results in other studies, nuclear and mitochondrial genes were found to change concordantly in a transect across the hybrid zone betweenBombina bombina andBombina variegata. mtDNAs of both species are found in populations in the central part of the zone, whereas populations at its margins contain mtDNA corresponding to nuclear genomes.     

Pheromone components of the female elephant hawk-moth,Deilephila elpenor,and the silver-striped hawk-moth,Hippotion celerio

By means of gas chromatographic and mass spectroscopic methods, and combined GC-electroantennogram and electrosensillogram techniques, (E)-11-hexadecenal and (10E, 12E)-10,12-hexadecadienal [(E,E)-bombykal is also the main constituent of the pheromone of the silver-striped hawk-mothHippotion celerio. The biological activity of the substances was demonstrated with electroantennogram and single cell recording, and the physiological efficacy of the different hexadecadienal isomers compared.Pheromones, 79; as Pheromones, 78 is taken: Wu, Cai-Hong, and Bestmann, H. J., Chinese Science Bulletin34 (1989) 1475; pheromones, 77: Attygalle, A. B., Steghaus0Kovac, S., Ahmed, V. U., Maschwitz, U., Vostrowsky, Ol, and Bestmann, H. J., Naturwissen-schaften78 (1991) 90.     

A specific protein in the genusRhynchosciara (Diptera,Sciaridae)

Summary Proteins immunologically related toRhynchosciara americana larval protein 10 occur in the hemolymph and ovaries of five different fly species of the genusRhynchosciara. Electrophoretic analyses showed these proteins to have a mol.wt similar to that of theR. americana protein 10 (43,000), e.g. theR. hollanderi protein 44,300, theR. milleri protein 45,500.     

Activity increases quantal size at the frog neuromuscular junction

Summary Two h of nerve stimulation at 10 Hz or of elevated spontaneous release in hypertonic solution increased the size of miniature end-plate potentials (m.e.p.p.'s) and currents at the frog neuromuscular junction, probably by increasing the amount of acetylcholine in a quantum. Increases in quantal size may modulate synaptic transmission.Acknowledgments. Supported by grant 10320 from the NINCDS and by a grant from the MDA. We are grateful to Dr I.S. Cohen for participating in some of the experiments and for helpful criticism, and to Drs C. Clausen and G. Baldo for help with the computer. Some of the results were presented at a meeting of the Physiological Society.     

A new 9,11-secosterol,stellettasterol from a marine spongeStelletta sp

A new 9,11-secosteroid, stellettasterol (1) was isolated from a Japanese marine sponge,Stelletta sp.; its structure was determined by spectroscopic analysis. All NMR signals of1 were unambiguously assigned by application of various 2D NMR techniques. Stellettasterol exhibited antifungal activity againstMortieralla ramannianus.Part 62 of the Bioactive Marine Metabolites series. Part 61: Fusetani, N., Takahashi, M., and Matsunaga, S., Tetrahedron, in press.     

Insect tissues,not microorganisms,produce linoleic acid in the house cricket and the American cockroach

Summary Biosynthesis of linoleic acid, 182(n–6), was unambiguously demonstrated to occur in the cockroach,Periplaneta americana, and the cricket,Acheta domesticus. Axenic tissue from both of these insect species was demonstrated by radio-gas-liquid chromatography (radio-GLC) and radio-high-performance liquid chromatography (radio-HPLC) to incorporate [1-¹⁴C]acetate and [1-¹⁴C]oleate into this essential fatty acid.This work was supported by the National Science Foundation under grant DCB-8914417. We would like to thank Coby Schal for his generous gift of American cockroaches and Tania Kellermeyer for her excellent technical assistance.     

Aberrant,canavanyl protein formation and the ability to tolerate or utilize L-canavanine

Summary L-Canavanine, 2-amino-4-(guanidinooxy)butyric acid, and L-arginine incorporation into de novo synthesized proteins was compared in six organisms. Utilizing L-[guanidinooxy¹⁴C]canavanine and L-[guanidino¹⁴C]arginine at substrate saturation, the canavanine to arginine incorporation ratio was determined in de, novo synthesized proteins.Caryedes brasiliensis andSternechus tuberculatus, canavanine utilizing insects;Canavalia ensiformis, a canavanine storing plant; and to a lesser extentHeliothis virescens, a canavanine resistant insect, failed to accumulate significant canavanyl proteins. By contrast,Manduca sexta, a canavanine-sensitive insect, andGlycine max, a canavanine free plant, readily incorporated canavanine into newly synthesized proteins. This study supports the contention that the incorporation of canavanine into proteins in place of arginine contributes significantly to canavanine's antimetabolic properties.     

A potent attractant of zoospores ofAphanomyces cochlioides isolated from its host,Spinacia oleracea

A highly potent attractant of zoospores ofAphanomyces cochlioides, a causal fungus of the root rot disease of spinach (Spinacia oleracea), was isolated from spinach roots, and its structure was determined by spectroscopic evidence and chemical synthesis as cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone,1). A chromosorb particle prepared by soaking in solution of1 showed a potent attracting activity toward the zoospores using concentrations of1 above 10^–9 or 10^–10 M.     

Detection of protease inhibitors in the hemolymph of resistantAnticarsia gemmatalis which are inhibitory to the entomopathogenic fungus,Nomuraea rileyi

Summary A complex of protease inhibitor activities has been detected in the hemolymph of the 6th instarAnticarsia gemmatalis larvae that are resistant to infection by the fungusNomuraea rileyi. A site-specific serine protease inhibitor extracted fromA. gemmatalis hemolymph inhibits both the germination ofN. rileyi conidia and subsequent germ tube development.     

A cyanoglucoside stored by aSedum-feeding Apollo butterfly,Parnassius phoebus

A bitter tasting cyanoglucoside, sarmentosin, was isolated from an aposematic Apollo butterfly,Parnassius phoebus, and from its plant-host,Sedum stenopetalum. The content of sarmentosin in the body tissues was as high as 500 g/insect, suggesting a defensive role for this substance; a high concentration was detected in the wings. Sarmentosin was also present in the eggs.     

On the specific attraction of the males of the six-toothed spruce bark beetle,Pityogenes chalcographus (L.) to a mixture of synthetic pheromones of the eight-toothed spruce bark beetle,Ips typographus (L.) (Coleoptera,Scolytidae)

Summary Traps containing a mixture of attractants forIps typographus also caught other species of bark beetles. The numbers ofPityogenes chalcographus, Pityogenes conjunctus, andTrypodendron lineatum were too high to be interpreted as accidental captures. The males of the polygamousP. chalcographus were specifically attracted, indicating that theI. typographus pheromone or one of its components acts as a kairomone and primary attractant for the pioneering males ofP. chalcographus.     

A novel antagonist of serotonergic receptors,hymenidin, isolated from the Okinawan marine spongeHymeniacidon sp.

Summary A novel bromine-containing pyrrole compound, hymenidin, has been isolated from the Okinawan marine spongeHymeniacidon sp. as a potent antagonist of serotonergic receptors and its structure elucidated using spectral data.     

A possible metabolic role foro-diphenoloxidase inMycobacterium leprae

Summary Among mycobacteria,Mycobacterium leprae is unique in its ability to oxidize a variety of diphenols to quinones in vitro. What physiologic roleo-diphenoloxidase has in the organism remained unknown. Reducing substrates like NADPH, NADH and ascorbic acid reacted with the quinone formed from dopa (3,4-dihydroxyphenylalanine); the substrates were oxidized and the quinone was reduced back to diphenol in the process. Since the quinone undergoes reversible oxidation-reduction, diphenoloxidase might serve as an alternative respiratory mechanism inM. leprae for the utilization of other substrates, as has been reported in plants.     

A multivariate approach to socio-ecological development and endocrine variance in the spotted hyaena,Crocuta crocuta Erxleben

This investigation of the socio-ecological development and endocrine variance in the spotted hyaena,Crocuta crocuta, illustrates that the complexity of a multivariate endocrine system cannot fully be understood using the concept of a class mean (). Any comprehensive investigation of a multivariate endocrine system should also include an analysis of variance (), as it may provide additional insights into the dynamics of an endocrine hypervolume. Mean cortisol concentrations could not differentiate between various social and reproductive categories (MANOVA); however, in males an analysis of variance (principal component analysis) indicated that the contrast between cortisol and androstenedione was the principle axis of variance once the androgen secreting ability had been accounted for. On the other hand, the same contrast was found to be the principal axis of variance in the female sub-sample, suggesting that cortisol may play a significant role in regulating the endocrine dynamics of this species, despite showing little variance in mean values among various social and reproductive categories.     

A new chromosome number forBombina (Anura,Discoglossidae)

Summary The karyotype of a primitive discoglossid anuran,Bombina maxima, native to southwestern China, has 2n=28 chromosomes with 6 large and 8 small bi-armed homologous pairs. This is a higher chromosome number than described for otherBombina species, all of which have 2n=24.