Biotransformation of a dietary sesterterpenoid in the Mediterranean nudibranchHypselodoris orsini

The metabolic relationship between the marine molluscHypselodoris orsini and the spongeCacospongia mollior has been reinvestigated. The predator-prey association has been confirmed even though the metabolic patterns of the two invertebrates are substantially different. Most probably the nudibranch converts the main sponge metabolite, the sesterterpenoid scalaradial (1), into a less oxygenated related metabolite, deoxoscalarin (4), followed by a second chemical transformation leading to a new sesterterpenoid, 6-keto-deoxoscalarin (5) which is selectively compartmentalized into some dorsal glands, mantle dermal formations (MDFs), strategically distributed near the gills. 6-keto-deoxoscalarin (5) has been characterized by 1D and 2D NMR methods. Finally, the unusual association of some Chromodorididae molluscs with sponges containing sesterterpenoids suggests a further analysis of their taxonomical collocation is required.     

Torus shaped bands at the 2R telomere region and at the region 68 of the salivary gland chromosomes ofDrosophila auraria

Summary The telomere of the 2R arm of the salivary gland chromosomes ofD. auraria exhibits a definite toroidal structure in routine squashed preparations, stained either by propionic orcein-carmine or by fluorescent dyes. There is evidence that a band (or bands) of region 68 (possibly homologous to that ofD. melanogaster) of the 3L chromosome arm also exhibits a toroidal structure. These toroids are associated with heterochromatin, but it is not certain that they are themselves heterochromatic.Acknowledgments. This work was supported by a grant from Volkswagenwerk-Stiftung to C.D.K. The outstanding technical assistance of Ms G. Karamanlidis is acknowledged.     

In vitro metabolism of the trichothecene 4-monoacetoxyscirpenol by fungus- and non-fungus-feeding insects

Summary The metabolism of the trichothecene 4-monoacetoxyscirpenol by intact gut tissue was determined in the fungus-feeding Nitidulid,Carpophilus hemipterus (L.) and the non-fungus-feeding caterpillars, the fall armyworm,Spodoptera frugiperda (J. E. Smith) and the corn earworm,Heliothis zea (Boddie). The primary metabolite was the hydrolysis product scirpentriol. The amount of metabolism by theC. hemipterus larvae was ca 10 times that of the caterpillars on a per mg protein basis, suggesting metabolic adaptation for feeding on fungi that may contain mycotoxins.Acknowledgment. The authors wish to thank S. Taylor for technical assistance.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Chromosome-breaking activity of extracts of the mushroomPaxillus involutus Fries ex Batsch

Summary Dry and presoaked seeds ofNigella damascena were treated with aqueous extracts of the mushroomPaxillus involutus. At the first mitosis after the onset of germination, metaphase chromosomes showed damage independent of the origin of the mushrooms. The damaging substance(s) is (are) thermostable. Except a few achromatic gaps, all the lesions observed are of the chromosome type, i.e. are induced at the pre-synthetic G1 stage.     

Gonyauline: A novel endogenous substance shortening the period of the circadian clock of a unicellular alga

Summary The circadian clock in the unicellular algaGonyaulax polyedra is accelerated by a substance in extracts from the cells themselves. The extracts have been fractionated using the circadian rhythm of bioluminescence as bioassay. The active substance, termed gonyauline, has been isolated and characterized as a novel low molecular weight cyclopropanecarboxylic acid (S-methyl-cis-2-(methylthio) cyclopropanecarboxylic acid). Synthetic gonyauline has a similar shortening effect on the period of the circadian clock.     

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.     

Transfer of secondary metabolites from the spongesDysidea fragilis andPleraplysilla spinifera to the mantle dermal formations (MDFs) of the mudibranchHypserlodoris webbi

The opisthobranch molluscHypselodoris webbi is able to select, among its potential preys, sponges chemically rich in furanosesquiterpenoids. The sequestered secondary metabolites act as defensive allomones against predators and are accumulated in some dorsal glands (MDFs). This transfer from sponges to MDFs has been proven by maintainingH. webbi together with some selected sponges in an aquarium for a prolonged period.     

β-Lactam resistance in Staphylococcus aureus: the adaptive resistance of a plastic genome

Staphylococci have two mechanisms for resistance to β-lactam antibiotics. One is the production of β-lactamases, enzymes that hydrolytically destroy β-lactams. The other is the expression of penicillin-binding protein 2a (PBP 2a), which is not susceptible to inhibition by β-lactam antibiotics. Strains of S. aureus exhibiting either β-lactamase or PBP 2a-directed resistance (or both) have established a considerable ecological niche among human pathogens. The emergence and subsequent spread of bacterial strains designated as methicillin-resistant S. aureus (MRSA), from the 1960s to the present, has created clinical difficulties for nosocomial treatment on a global scale. The recent variants of MRSA that are resistant to glycopeptide antibiotics (such as vancomycin) have ushered in a new and disconcerting chapter in the evolution of this organism. Received 2 April 2005; received after revision 15 July 2005; accepted 25 July 2005     

Selected decrease of haemocytes of the freshwater snailPlanorbarius corneus (L.) (Gastropoda,Pulmonata) after bacteria injection

Summary The decrease of haemolymph phagocytic cells (SH) inPlanorbarius corneus after bacterial injection seems to be mediated by humoral factor(s) released into the haemolymph. SH show different adhesiveness in vitro in the presence of bacterial metabolic products.     

Response of the starling circadian system to transitions between light and darkness

Summary The effects of exposure to sudden transitions from dark to light (D/L) and light to dark (L/D) were determined on the free running circadian feding rhythm of European stalings (Sturnus vulgaris). D/L transitions (step-up) produced phase advances throughout the circadian cycle. In contrast L/D transitions (step-down) produced both advances and delays. The L/D transition phase-response curve has a contour and shape similar to the phase-response curves previously obtained in birds with light pulses.     

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.     

Photodecomposition of orellanine and orellinine,the fungal toxins ofCortinarius orellanus Fries andCortinarius speciossimus

Summary The photosensitivity of orellanine, the main toxin ofCortinarius orellanus Fries mushrooms, and its transformation to orelline via orellinine is discussed. All three substances were found in methanolic extracts ofCortinarius orellanus andCortinarius speciossimus mushrooms. The problem of homogeneity of orellanine is also discussed.Acknowledgment. The authors wish to express their gratitude to Prof. Dr W. Steglich from the Institut für Organische Chemie und Biochemie der Universität Bonn (Federal Republic of Germany) for having provided them with a sample of dried material ofC. speciossisimus.     

Instar-specific defensive secretions of stink bugs (Heteroptera: Pentatomidae)

Defensive secretions (allomones) from first-instar nymphs of stink bugs in the subfamily Pentatominae contain (E)-4-oxo-2-decenal as a major constituent, whereas this compound is absent from later instars. In contrast, first instars ofEdessa meditabunda (Edessinae) produce allomones like those of later instars. The C₆ and C₈ (E)-4-oxo-2-alkenals are common, characteristic exocrine compounds of nymphal and adult Heteroptera, but (E)-4-oxo-2-decenal is previously unknown as a major natural product for which a biological role has yet to be established.     

Isolation and characterization of hemagglutinins from the spongeDysidea herbacea

Summary The spongeDysidea herbacea (Keller) was found to possess hemagglutinins. The major component, DHA-I, is a protein with a mol.wt of 26,000, which dissociates into subunits of equal size (14,000). It contains large amounts of glutamic acid and aspartic acid residues, but no half-cystine, methionine or histidine residues. DHA-I reacted with rabbit and human AB0 erythrocytes. D-galactose and lactose were effective inhibitors of DHA-I. The sponge also contained a minor component(s) which reacted preferentially with rabbit erythrocytes but not with human AB0 erythrocytes.Acknowledgment. We thank Dr. M. Yamazaki, Faculty of Pharmaceutical Sciences, Teikyo University, for testing mitogenic activity ofDysidea agglutinins. This study was partly supported by a grant-in-aid for Overseas Scientific Survey from the Ministry of Education, Science and Culture, Japan.     

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.     

What leads from <Emphasis Type="Italic">dead-end?</Emphasis>

The 129 mouse strain develops congenital testicular germ cell tumors (TGCTs) at a low frequency. TGCTs in mice resemble the testicular tumors (teratomas) that occur in human infants. The genes that cause these tumors in 129 have not been identified. The defect at the Ter locus increases TGCT incidence such that 94% of 129-Ter/Ter males develop TGCTs. The primary effect of the Ter mutation is progressive loss of primordial germ cells (PGCs) during embryonic development. This results in sterility in adult Ter/Ter mice on all mouse strain backgrounds. However, on the 129 background, Ter causes tumor development in addition to sterility. Therefore, Ter acts as a modifier of 129-derived TGCT susceptibility genes. Ter was identified to be a mutation that inactivates the Dead-end1 (Dnd1) gene. In this perspective, I discuss the possible areas of future investigations to elucidate the mechanism of TGCT development due to Dnd1 inactivation. Received 29 September 2006; received after revision 29 January 2007; accepted 19 February 2007     

Fitness traits associated with the red back phenotype in the migratory grasshopper,Melanoplus sanguinipes

Summary The dominantly inherited variant, red back, in the migratory grasshopper,Melanoplus sanguinipes, is rare in nature. The present study illustrates that is this probably due, in part, to the trait's association (either through pleiotropy of the red back gene,Pro and/or closely linked fitness loci) with lower egg hatchability, greater developmental time, greater mortality during later stages, and a greater tendency to have an extra instar.A part of an M.Sc. thesis of F. R. H. Hodson, University of Regina (1985).Financial assistance from the Natural Sciences and Engineering Research Council (A0485) is greatfully acknowledged. Address reprint requests to W.C.