Two mechanisms in the biological clock ofPieris brassicae L.: an oscillator for diapause induction; an hour-glass for diapause termination

Summary Resonance experiments for photoperiodic termination of pupal diapause demonstrated thatPieris brassicae uses a night-measuring hour-glass mechanism. In previous work the same resonance technique for diapause induction revealed that photoperiodic time-measurement is a function of the circadian system. For the first time in a living organism it has been shown that the biological clock operates by means of an oscillator for photoperiodic onset of a phenomenon and according to an hour-glass system for photoperiodic termination.     

Photoperiodic induction of diapause in an insect is vitamin A dependent

Summary A photoperiodic response was found to be absent in larvae of the parasitoid waspApanteles glomeratus when its host (caterpillars ofPieris brassicae) was reared on a low-carotenoid artificial diet. Addition of vitamin A to the host's diet restored the response to short-day photoperiods in the wasp larvae, thus showing that vitamin A is essential for photoperiodic induction of diapause. Possibly vitamin A or a derivative of vitamin A functions as the photoreceptor pigment for the photoperiodic reaction in this species of insect.     

Regulatory steps in sex pheromone biosynthesis inMamestra brassicae L. (Lepidoptera: Noctuidae)

Summary The de novo biosynthesis of (Z)-11-hexadecenyl acetate, the most abundant pheromone component inM. brassicae, starting from acetate via palmitic acid, requires the presence of a pheromone-biosynthesis-activating neurohormone. Moreover, the conversion of palmitic acid to (Z)-11-hexadecenyl acetate is strongly dependent on the presence of the neurohormone. However, no significant dependence was found for the conversion of (Z)-11-hexadecenoic acid to (Z)-11-hexadecenyl acetate. This indicates that the neurohormonal control of pheromone biosynthesis inM. brassicae occurs at the level of palmitic acid.     

Effects of diapause and host species on some morphometric characters inTrichogramma (Hym.: Trichogrammatidae)

Adult morphology ofTrichogramma is modified by environmental conditions during the preimaginal development. For instance, the low temperatures inducing diapause cause a decrease of the ratio length of longest seta on male flagellum/width of flagellum inT. evanescens. The species of the host also influences numerous body ratios. So, in females, the development of tibiae with regard to wings is more important withScotia ipsilon than withGalleria mellonella. These results confirm the necessity of performing comparative morphological studies on individuals reared in the same conditions.     

Prostaglandin (15S)-PGA2 derivatives in the gorgonianPlexaura homomalla (Esper), formakükenthali Moser

Summary The lipid fraction, 17%, of air-driedPlexaura homomalla formakükenthali, collected in the Caribbean at Puerto Rico, yielded 50% of its weight as the mammalian prostaglandin (15S)-PGA₂ methyl ester. The freeze-dried gorgonian yielded (15S)-PGA₂ largely as the acetate of the methyl ester. (15S)-PGA₂ was also obtained from material collected at St. Croix and at South Caicos. Field observations indicate thatPlexaura kükenthali may be a species separate fromPlexaura homomalla and that it is abundant on some shallow water reefs in the Caribbean. Prostaglandins could not be detected in the lipid fraction of eggs isolated fromPlexaura homomalla (Esper) formahomomalla.Acknowledgments. We gratefully acknowledge support from the Office of Sea Grant, NOAA, Department of Commerce (Grant 047-158-44067), and the use of facilities at the Isla Mayagues Marine Laboratory of the University of Puerto Rico, Mayaguez, the West Indies Laboratory of Fairleigh Dickinson University at St. Croix, U.S.V.I., and the Marine-Biologisch Instituut at Curacao. Special thanks to Dr. F.M. Bayer, Curator, Department of Zoology, National Museum of Natural History-Smithsonian Institution for checking identity of gorgonians used in this study.     

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.     

Hydroxylation of menthols and cineoles withm-chloroperbenzoic acid

Summary Reaction of menthols and cineoles withm-chloroperbenzoic acid afforded tertiary, secondary, and primary alcohols, some of which were natural products having potent plant growth regulatory activity or were mammlianm metabolies.We thank Nippon Terpene Co. Ltd for their generous gift of the compounds used in this work and Drs M. Kido and Y. Fukuyama, Otsuka Pharmaceutical Co. Ltd, for measurement of high resolution mass spectra. The present work was supported in part by a Grant-in-Aid for Cancer Research from the Ministry of Health and Welfare.     

Single amino acid substitutions insn-glycerol-3-phosphate dehydrogenase allozymes fromDrosophila virilis

Summary The amino acid sequence was compared among the three allelic variants (allozymes) ofsn-glycerol-3-phosphate dehydrogenase inD. virilis, which are detected by one-dimensional electrophoresis. The GPDH^f variant was different from the GPDH^m by only one substitution of 68-lysine for asparagine; GPDH^s differed from GPDH^m by substitution of 127-glycine for arginine. No electrophoretically silent substitutions were found in a total of 352 amino acid residues.     

Determination of diel periodicity of sex pheromone release in three species of Lepidoptera by ‘closed-loop-stripping’

Summary By means of closed-loop-stripping and subsequent GC analyses the diel periodicity of release of (Z)-11-hexadecenyl acetate, (E)-8-dodecenyl acetate, and (Z)-9-tetradecenyl acetate, the main constituents of the respective sex pheromone blends ofMamestra brassicae, Cryptophlebia leucotreta andSpodoptera sunia females, was determined.Pheromones, 64. For the 63rd contribution we have taken from: Szöcs, G., Toth, M., Bestmann, H. J., Vostrowsky, O., Heath, R. R., and Tumlinson, J. H., Z. Naturforsch.42c (1987) 165; Pheromones, 62: Bestmann et al.¹³.     

Partial purification and characterization of acid phosphatase from sporulated oocysts ofEimeria tenella

Summary Acid phosphatase ofEimeria tenella oocysts (Peak II) was purified 77-fold with a recovery of 26% using protamine sulfate precipitation, DEAE-cellulose chromatography and Sephadex G-200 gel filtration. This enzyme occurs in multiple forms as indicated by two peaks which can be separated by DEAE-cellulose chromatography and polyacrylamide gel electrophoresis. The partially purified enzyme has optimal activity at pH 4.5. With p-nitrophenyl phosphate the Km and V_max values for (Peak II) were 25 mM and 1.57 mol/min/mg protein, respectively. The enzyme (Peak II) ist strongly inhibited by Hg⁺⁺, Cu⁺⁺, iodoacetamide, fluoride and molybdate. Tartrate and other divalent metal ions have no effect on enzyme activity. The partially purified Peak II phosphatase is not a glycoprotein as it is not absorbed on concanavalin-A Sepharose and its treatment with bacterial neuraminidase does not alter its elution profile through DEAE cellulose.     

Studies on the fungal phytotoxin victorin: Structures of three novel amino acids from the acid hydrolyzate

Summary The host-selective phytotoxin victorin, produced by the fungusCochliobolus victoriae, was found to be at least partially peptidic in nature, and did not contain victoxinine. The exact mass of the M-H ion was measured by FABMS as 795.1877. Derivatives of three major acid hydrolysis products were isolated. The structures of the corresponding amino acids were assigned as 2S,3R-3-hydroxyleucine, 5,5-dichloroleucine, and 3-hydroxylysine. A into victorin by the fungus in vivo.     

Effect of aloe lectin on deoxyribonucleic acid synthesis in baby hamster kidney cells

Summary A homogeneous glycoprotein (mol.wt 40,000) containing 34% carbohydrate was isolated fromAloe arborescens var.natalensis. At a concentration of 5 g/ml, this glycoprotein was shown to stimulate deoxyribonucleic acid (DNA) synthesis in baby hamster kidney (BHK) cells and to have the properties of a lectin which reacts with sheep blood cells. The chemical and physical properties of the glycoprotein (aloe lectin) are also discussed.     

A blue light-reversible reaction in an animal system (Daphnia pulex)

Summary A photoreversible reaction, previously found only in plants and fungi, has now been found in an animal system. Activation of development in diapausing embryos ofDaphnia pulex, induced with white light, was suppressed with subsequent exposure to narrow-band (470 nm) or wide-band (410–525 nm) blue light. Pulses of wide-band blue light repeatedly reversed white light activation.     

Secreted oleanolic acid on the cuticleOlea europaea (Oleaceae); a chemical barrier to fungal attack

Summary The leaf of the bitter oliveOlea europaea (Oleaceae) is heavily coated by almost pure oleanolic acid, which forms part of a multichemical defense against fungal attack.We thank Mr K. A. Hoelmer for taking the electron micrographs and also Professor T. Kamikawa for NMR measurements.     

Effect of xanthurenic acid on P-450-dependent biotransformation by molting glands in vitro

Incubation of molting glands from the crayfishProcambarus clarkii (Y-organ) and the silkwormBombyx mori (prothoracic gland) with 23,24-[²H₄]-2-deoxyecdysone resulted in the production of deutero-ecdysone; this biotransformation was inhibited in the presence of xanthurenic acid. When the experiments were performed under an¹⁸O₂ atmosphere, the¹⁸O atom was introduced into ecdysone, as confirmed by mass spectrometry. We therefore suggest that xanthurenic acid inhibits P-450-dependent hydroxylation of 2-deoxyecdysone. However, deutero-2-deoxyecdysone was not converted to 3-dehydroecdysone when using Y-organs in vitro, although it is a major product. We therefore conclude that the biosynthetic pathway of ecdysteroids inP. clarkii branches at an early step.     

Juvenile hormone I is the principal juvenile hormone in a hemipteran insect,Riptortus clavatus

Juvenile hormone I (JH I) was identified by combined gas chromatography/mass spectrometry as the predominant JH in the hemolymph of female adults of the bean bug,Riptortus clavatus (Thunberg) (Hemiptera: Alydidae). Among JH I, II, and III, JH I was the most effective hormone for inducing the synthesis of yolk proteins in diapause adults.     

Isolation of indole-3-acetic acid methyl ester,a metabolite of indole-3-acetic acid fromPseudomonas amygdali

From the culture filtrates ofPseudomonas amygdali the methyl ester of indole-3-acetic acid (IAA), a product of indole-3-acetic acid metabolism which has the same auxin activity as the free acid, has been isolated. This is the first report of its occurrence as a microbial metabolite.     

Primitive actimoterigian fishes can synthesize ascorbic acid

Amphibians and reptiles evolved with the capacity to synthesize ascorbic acid. Some higher vertebrates, like bats, guinea pigs, primates, and humans have lost the microsomal enzyme gulonolactone oxidase, and in cases of ascorbic acid deficiency suffer from symptoms of scurvy. The question of whether the capacity to synthesize ascorbate is also present in lower vertebrates could throw light on the evolution of this pathway. In order to find out whether ascorbic acid synthesis took place in two primitive Actinopterigian fish, the paddlefish (Polydon spathula) and the white sturgeon (Acipenser transmontanus) were fed with a scorbutogenic diet or diet(s) supplemented with a graded level of ascorbic acid. We found no growth depression nor external symptoms of scurvy, which would be pronounced in modern bony fishes (Teleostei) under similar conditions. The tissue level of ascorbate in both these primitive species indicated that vitamin C in intestine and liver is not depleted when fed a scorbutogenic diet. Gulonolactone oxidase activity was found in the kineys of the Actinopterigian fishes. Thus, I question the accepted evolutionary pathway for ascorbic acid biosynthesis in lower vertebrates and suggest that the modern bony fishes,Teleostei, lost their ability to express the gulonolactone oxidase genes after they had separated during the Silurian from their common ancestor with the coelacanths (Latimeria) and Dipnoi.     

Age-dependent tolerance toBaculovirus in last larval instars of the codling moth,Cydia pomonella,L., induced either for pupation or for diapause

Summary LD₅₀ values as well as time-dependent parameters of granulosis virus infections were determined at different times during the last larval instar (L₅) of the codling moth,Cydia pomonella L., induced either for pupation or for diapause. A significant increase of tolerance to virus was found in 48-h-old L₅ induced for pupation, and 24 h later in L₅ induced for diapause.