Starfish saponins. Part 101. Further 24-O-glycosidated steroids from the starfishHacelia attenuata

Summary On the basis of comparative spectral data, the structures of 3 novel steroidal glycosides from the Mediterranean starfishHacelia attenuata have been elucidated as3, 4 and5. These are further examples of a novel group of 24-O-glycosidated steroids recently encountered in the same species and in the Pacific speciesProtoreaster nodosus.Part 9. L. Minale, C. Pizza, R. Riccio and F. Zollo, Experientia39 (1983) 567. This contribution is part of the Progetto Finalizzato Chimica fine e secondaria del C.N.R., Roma.Acknowledgments. We thank Prof. K. Nakanishi, Columbia University, New York, for FD-mass spectral analyses, the Centro Interfacoltà di Metodologie Chimico-Fisiche for 270 MHz NMR facilities, and Miss R. Aquino for part of the experimental work.     

Genetic variability in 3 co-occurring forms of the starfish genusOthilia (=Echinaster)

Summary High levels of genetic variability have been found in 3 (grey, brown, orange) co-occurring forms of the starfishOthilia. These high levels appear to correspond to the generalistic habit of this starfish. The biochemical data, coupled with morphological observations, indicate that the grey and orange forms are morphs of the same species and that the brown form is a species separate from the grey and orange forms.     

Marine eicosanoids: Occurrence of 8-(R)-HETE in the starfishPatiria miniata

Summary The first isolation of 8-(R)-hydroxy-5Z, 9E, 11Z, 14Z-eicosatetraenoic acid [8-(R)-HETE] from a marine source, the pacific starfishPatiria miniata, is reported. 8-(R)-HETE occurs together with 8-(R)-hydroxy-5Z, 9E, 11Z, 14Z, 17Z-eicosapentaenoic acid.     

Occurrence of tetrodotoxin in the starfishAstropecten latespinosus

Summary A toxin causing paralysis was detected in the starfishAstropecten latespinosus. The toxin was purified by a method consisting of charcoal treatment and chromatography on CM-Sephadex C-25 and Bio-Rex 70. The toxin was identified as tetrodotoxin by its behavior in thin-layer chromatography and electrophoresis and its¹H-NMR spectrum.Acknowledgment. This work was in part supported by a research fund from the Ministry of Agriculture, Forestry and Fisheries of Japan.     

One-sided sexual isolation betweenDrosophila takahashii andDrosophila pseudotakahashii

Summary In order to elucidate the phylogenetic relationships betweenD. takahashii andD. pseudotakahashii, 2 closely related allopatric species, sexual isolation was studied by the male-choice method. The present data indicate that there is a one-sided mating preference between these species. On a basis of the results, their evolutionary sequence is discussed.We are indebted to Dr I. R. Bock, Australia, and Dr O. Kitagawa, Japan, for kindly providing the live cultures. Thanks are due to the Head of the Zoology Department, B.H.U. for the provision of laboratory facilities and to the C.S.I.R., New Delhi, India, for awarding a Post-doctoral fellowship to Y.N.D.     

The antennae and mating behaviour ofDrosophila females

Summary The females ofDrosophila bipectinata andD. malerkotliana are able to discriminate between their own and alien males in the absence of antennae. Thus mate recognition seems to depend on contact chemoreceptors in these 2 species.We are grateful to the Head of the Department of Zoology, B.H.U. for providing the necessary facilities. Thanks are due to the U.G.C., New Delhi, India for awarding a junior research fellowship to O.P.S.     

A new neurosecretory system in fish,located in the gill region

Summary A peculiar neurosecretory system is reported in 6 teleost species;Clarias batrachus, Heteropneustes fossilis, Mystus seenghala, Ompak pabda, Glassogobius giuris andNotopterus notopterus. It is located in the gill region close to the pseudobranch or to the carotid labyrinth. The neurosecretory cells have been identified using stains specific for neurosecretion. The results are discussed in the light of the association of the neurosecretory system with the pseudobranch or the carotid labyrinth, and the airbreathing habit of these fishes.We are grateful to Prof. U.S. Srivastava for providing laboratory facilities and for encouragement. The work was financially supported by U.G.C. Research Project grant awarded to C.B.L.S., which is thankfully acknowledged. Thanks are due to M. Seal and Amarlata for technical help rendered.     

Influence of seed size and composition on the dry matter yield ofCenchrus ciliaris

Summary Higher food reserve in larger seeds ofCenchrus ciliaris contributed towards greater forage production, as compared to that of the small seeds, only during the 1st year of establishment.Acknowledgment. Thanks are due to Dr H.S. Mann, Director of this Institute for providing facilities. Technical support provided by Mr M. Ram is duly acknowledged.     

Germ cell chromosomes in two species of terrestrial isopods from India

Summary In 2 species of terrestrial isopods, namelyPorcellio assamensis andP. laevis, the diploid and haploid numbers of chromosomes have been established to be 48 and 24 respectively for the former species and 50 and 25 respectively for the latter species. Female heterogamety of the ZW type has been found to exist inP. laevis.The authors express their sincere thanks to Prof. G.P. Sharma, and to Prof. S. Khera, Department of Zoology, Panjab University, Chandigarh, for the necessary laboratory facilities.     

Two related butterfly species avoid oviposition near each other's eggs

Summary Some butterfly species avoid egg-laying on plants which already bear conspecific eggs, and thus reduce food competition between their offspring. In twoPieris species the females produce in their accessory glands an oviposition-deterring pheromone (ODP), which is combined with the egg during oviposition. The ODP collected from eggs or accessory glands ofP. brassicae inhibits oviposition byP. rapae and vice versa. The ODP of either species stimulates tarsal receptors in both species. The antennae of the two pierids respond to the volatiles of their own and each other's eggs. Thus the ODPs of the two species may reduce not only intraspecific, but also interspecific food competition between their larvae.     

3-Methyl-2-hexanone from the triatomine bugDipetalogaster maximus (Uhler) (Heteroptera; Reduviidae)

Summary The occurrence of 3-methyl-2-hexanone as a major component of the secretion and possible alarm substance from the metasternal scent glands in the triatomine bugDipetalogaster maximus is reported.The authors are indebted to Mr B.O.C. Gardiner of the Zoology Department, Cambridge, for a supply of livingDipetalogaster. They would like also to thank Dr D.E. Games for the provision of mass spectral facilities under support from the S.E.R.C.     

Eco-physiological studies onZornia diphylla pers. with reference to adaptive seed dormancy

Summary Seeds ofZornia diphylla possess a complex type of dormancy which is of great survival value for the species. Seeds show polymorphism. The optimum temperature for germination explains the cause of its distribution in the tropics. The grazing and scraping promotes the vegetative growth.The author is grateful to Dr.R. Sahai and Dr.R. S. Tripathi, Gorakhpur University, for guidance and to Dr.Y. B. Singh, Principal, and Dr.G. C. Srivastava, Head Dept. Botany, for encouragement and facilities. Thanks are due to my colleagues late SriP. N. Gupta, SriJ. Abraham, SriF. Abbasi, and Dr.A. B. Sinha for their cooperation.     

Conotoxins and the posttranslational modification of secreted gene products

The venoms of predatory cone snails (genus Conus) have yielded a complex library of about 50–100,000 bioactive peptides, each believed to have a specific physiological target (although peptides from different species may overlap in their target specificity). Conus has evolved the equivalent of a drug development strategy that combines the accelerated evolution of toxin sequences with an unprecedented degree of posttranslational modification. Some Conus venom peptide families are the most highly posttranslationally modified classes of gene products known. We review the variety and complexity of posttranslational modifications documented in Conus peptides so far, and explore the potential of Conus venom peptides as a model system for a more general understanding of which secreted gene products may have modified amino acids. Although the database of modified conotoxins is growing rapidly, there are far more questions raised than answers provided about possible mechanisms and functions of posttranslational modifications in Conus. Received 24 June 2005; received after revision 13 August 2005; accepted 19 September 2005     

Low ambient oxygen tolerance in some freshwater teleosts

Summary Measurements of the asphyxial oxygen level forRhinomugil corsula, Tilapia mossambica, Puntius sarana andCarassius auratus at 30 and 35°C revealed that at 35°C the lethal oxygen level was higher forT. mossambica andP. sarana and lower forR. corsula, but it remained the same forC. auratus at 30 and 35°C. From a thesis (M.P.M.) approved for the degree of Doctor of Philosophy, Madurai Kamaraj University, madurai, India. We wish to express our thanks to Prof. S. Krishnaswamy for providing facilities and to Dr S.V. Job for suggestions.     

Natural hybridization inDrosophila

Summary Although at least 159 cases of interspecific hybridization between closely related species ofDrosophila have been obtained under laboratory conditions, only 7 cases of natural interspecific hybridization have been recorded. We report yet another case, concerningD. malerkotliana andD. bipectinata.Thanks are due to the University Grants Commission for supporting the research project of J.P.G. and to the Head of the Department for laboratory facilities.     

Plants are better protected against spider-mites after exposure to volatiles from infested conspecifics

When infested by herbivorous mites, cotton seedlings produce volatile cues that elicit attraction of predatory mites. Experiments were carried out to elucidate how downwinduninfested conspecific seedlings are affected by these volatiles. It was found that the rate of oviposition of herbivorous mites was reduced on seedlings exposed to volatiles from infested seedlings. Moreover, predatory mites were attracted by exposeduninfested seedlings. These results strongly suggest that uninfested plants are better protected against herbivore attack when exposed to airborne chemicals released by their infested neighbours.     

Notable diversity in hemoglobin expression patterns among species of the deep-sea clam, <Emphasis Type="Italic">Calyptogena</Emphasis>

The deep-sea clams Calyptogena nautilei and C. tsubasa, which live in the cold-seep area at a depth of 3570 m in the Nankai Trough, Japan, have abundant hemoglobins (Hbs) in erythrocytes, similar to other Calyptogena species. We determined the cDNA-derived amino acid sequences of Hbs from two Calyptogena species. C. tsubasa was found to contain two dimeric Hbs, Hb I consisting of 145 amino acid residues and Hb II with 137 residues, similar to known Hbs from C. soyoae and C. kaikoi. Sequence identity was over 90% among the orthologous chains of Calyptogena Hbs. On the other hand, surprisingly, C. nautilei contained two monomeric Hbs, Hb III containing 141 residues and Hb IV with 134 residues. In addition, Hbs III and IV showed only 33–42% sequence identity with Hbs I and II from other Calyptogena species. The distal (E7) histidine, one of the functionally important residues of the heme protein, is replaced by glutamine in all Hb chains of Calyptogena species. A phylogenetic analysis indicated that C. nautilei Hb III is closer to Hb I from other Calyptogena species. We suppose that a Hb gene was duplicated at least three times in an immediate ancestor of Calyptogena and, presumably depending on physiological conditions different Hb sets are being expressed: dimeric Hbs I and II in C. soyoae, C. kaikoi and C. tsubasa, and monomeric Hbs III and IV in C. nautilei. Received 13 May 2003; received after revision 5 June 2003; accepted 12 June 2003     

High genetic variability despite haplodiploidy in primitive sawflies of the genusCephalcia (Hymenoptera,Pamphiliidae)

Hymenoptera are haplodiploid and usually display very low genetic variation. Most data concern social or parasiticApocrita, while the little information available for the primitive phytophagous species of the suborder Symphyta is contradictory. The present study is related to seven species of the genusCephalcia, living in coniferous forests of Northern Eurasia and sharing spruce (Picea sp. pl.) as host plant. Individuals from 22 populations belonging toCephalcia abietis, C. alashanica, C. arvensis, C. erythrogaster, C. fallenii, C. fulva, C. klugii from Europe and China were surveyed for genetic variation at 28 loci using enzyme electrophoresis. Pairs of sibling species were recognized withinC. arvensis andC. fallenii, corresponding to different phenological and morphological forms. In the latter case, reproductive isolation in sympatry occurs despite low genetic distance (D=0.059). Large genetic distances and fixed alternate alleles were observed between Chinese and European populations ofC. abietis andC. arvensis. Expected heterozygosity ofCephalcia populations (0.197, SD 0.064) is significantly higher than that of other Symphyta (Tenthredinoidea) (averageH _exp 0.059, SD 0.032) (two-tailed Mann-Whitney test, Z=4.39, p<0.01). These data suggest that haplodiploidy per se does not reduce the genetic variation in mostCephalcia populations. Most of the factors that can lower the potential for genetic diversity in a haplodiploid genetic system are not so effective inCephalcia populations, which seem to be comparable to diplodiploid insect populations in diversity. In a few isolated populations the large number of fixed loci and the large genetic distances may support the predicted faster rate of fixation, as a consequence of haplodiploidy.     

Chromosomal evolution and zoogeographic origin of southeast Asian shrews (genusCrocidura)

To the origins and evolution of Indomalayan shrews, we investigated the chromosomal variations of 14 species ofCrocidura from SE Asia. Intraspecific polymorphism was mainly due to variation in the number of short chromosomal arms butC. lepidura andC. hutanis showed a polymorphism due to a centric fusion. The undifferentially stained karyotypes were similar in 9 species, all possessing 2n=38 and FN=54–56 (68);C. fuliginosa had 2n=40 and FN=54–58. These karyotypes are close to the presumed ancestral state for the genusCrocidura. Four species from Sulawesi had a reduced diploid number (2n=30–34), a trend not observed among other SE Asian species but present in few Palaearctic taxa. Compared to the apparent stasis of karyotypic evolution observed among other SE Asian species, the high degree of interspecific differences reported among Sulawesian shrews is unusual and needs further investigation.Stasis and reduction in diploid number found in both Indomalayan and Palaearctic species suggest that these two groups share a common ancestry. This is in sharp contrast to most Afrotropical species which evolved towards higher diploid and fundamental numbers. The zoogeographical implications of these results are discussed.     

Karyotypes and nuclear DNA contents of Polypteridae (Osteichthyes)

Summary Calamoichthys calabaricus, Polypterus palmas, P. weeksii, P. delhezi andP. ornatipinnis have the same amount of DNA per erythrocyte nucleus. The karyotype ofP. weeksii has 38 chromosomes and differs from the karyotypes of the other species, all with 36 chromosomes, by a Robertsonian chromosomal rearrangement. The karyotype condition is regarded as derived for vertebrates.Research supported by the Division of Human Genetics, K.U. Leuven, Belgium and the UNAZA, campus Kinshasa, Zaire. The Department of Human Genetics, University of Amsterdam, Netherlands, provided facilities for cytophotometry.