Observations on the fine structure of the cercaria of Notocotylus attenuatus and formation of the cyst wall of the metacercaria

Summary The dorsal tegument of the mature cercaria of Notocotylus attenuatus is a syncytial, cytoplasmic layer, containing two types of secretory granule which are identifiable ultrastructurally. The type 1 secretory bodies are electron lucid, whereas most type 2 granules have a banded appearance. The ventral tegument contains granules which are secreted from the type 3 cells; the type 3 granules are membrane bound, electron dense, and consist of both an amorphous and a finely striated zone. The type 4 cells mainly contain cigar-shaped granules consisting of an amorphous core surrounded by concentric striations. The granules exhibit structural variability in shape and content. The type 4 cells undergo a cellular migration to the tegument during encystment. The structure of the posterior-lateral glands and mode of secretion of the granules are described. Possible functions of microtubules are discussed for each cell type. Details of some secretory processes involved in the formation of the hemispherical cyst wall are described. The layers of the cyst wall may be related to the granular contents of the various parenchymal cells of the cercaria. The tegument of the metacercaria originates primarily from the cytoplasm of the type 1, type 2, type 3 and type 4 cells.     

Roles of dopa decarboxylase and phenoloxidase in the melanization of the tobacco hornworm and their control by 20-hydroxyecdysone

Summary WhenManduca sexta larvae are allatectomized 5 h before head capsule slippage (HCS) in the final larval molt, the new larval cuticle contains granules that melanize 3 h before ecdysis when the ecdysteroid titer falls (Curtis et al. 1984). In both the epidermis and hemolymph of these allatectomized larvae dopamine was higher than dopa prior to and at the time of melanization. Dopamine also increased in the new cuticle as melanization began. Dopa decarboxylase (DDC) activity increased in the epidermis, cuticle, and fat body beginning 16 h after HCS, with a two-fold greater increase in the epidermis of allatectomized larvae. Both -MDH and -fluoromethyl-dopa inhibited epidermal DDC activity and inhibited melanization in vitro when dopa was used as a precursor. Addition of dopamine to the medium allowed melanization in the presence of the inhibitors. All these results indicate that dopamine is likely the primary precursor of cuticular melanin. The diphenoloxidase in the premelanin granules was activated in vivo between 19 and 21 h after HCS and was found to prefer dopamine to dopa and not to convert tyrosine to melanin. The activation of the prophenoloxidase was inhibited by 20-hydroxyecdysone (20-HE), both in vivo and in vitro, if hormone was given by 16 h after HCS. Infusion of 1.2 g/ml 20-HE into allatectomized larvae for 24 h from HCS prevented both the increase in DDC activity and the activation of the premelanin granules. Although the larvae ecdysed after a 15 h delay, melanization never occurred.Abbreviations -MDH L-3-(3,4 dihydroxyphenyl)-2-hydrazine-methylpropionic acid - -FM-dopa R-S--fluoromethyl-dopa - DCC dopa decarboxylase - 20-HE 20-hydroxyecdysone - JH juvenile hormone - HCS head capsule slippage     

Ultrastructure of four types of striated muscle fibers in the atlantic hagfish (Myxine glutinosa,L.)

Summary Four types of striated muscle fibers with distinctive ultrastructure were defined in the Atlantic hagfish (Myxine glutinosa, L.): white, intermediate, and red fibers of m. parietalis, and red fibers of m. craniovelaris.White fibers are thick, contain very few mitochondria and fat vacuoles, and possess distinct and separate myofibrils with thin Z-disks and distinct M-lines. Intermediate fibers are thinner, possess largely similar myofibrils that often are even better separated due to a higher content of fat vacuoles and especially mitochondria and glycogen granules. Red fibers of m. parietalis contain large amounts of mitochondria, fat vacuoles, and glycogen granules. Their myofibrils possess M-lines, and although branching more, the myofibrils of red fibers conform with a Fibrillenstruktur pattern like those of white and intermediate fibers. Red fibers of m. craniovelaris are very thin, possess many smaller fat vacuoles, and large amounts of mitochondria and glycogen granules. The myofibrils are significantly thinner than in m. parietalis fibers, run as quite independent well separated units, possess thicker Z-disks, and lack M-lines. Large amounts of myosatellite cells are associated with these red fibers.Triads are located near A/I-junctions in all four fiber types and occur irregularly, the density of triads being different in the various fiber types.We are indebted to Dr. Finn Walvig, Biological Station, University of Oslo, Drøbak, for supply of hagfishes, and we also wish to thank Dr. Jan K. S. Jansen, Institute of Physiology, University of Oslo, for valuable suggestions during this study.     

Cytochemical demonstration of amine-storing vacuoles and lysosomes in the chicken thrombocytes

Summary A combined electron microscopic and cytochemical study of the thrombocytes of the chicken has clearly identified the amine-storing organelles and lysosomes. A chormaffin positive-reaction product was observed on the inner surface and the granules of the large electronlucent vacuoles. No acid phosphatase activity was localized in these amine-storing vacuoles. However, the acid phosphatase activity was observed in the small vesicles, the primary lysosomes, and in the large electron dense inclusions with myelin which may be secondary lysosomes. The results of this study suggest that the large empty vacuoles, with one or two very dense osmiophilic peripherally-situated granules, in the chicken thrombocytes are comparable to the vesicles with electron dense materials called dense bodies in mammalian thrombocytes.To whom offprint requests should be sent     

DNA variations in regenerated plants of pea (Pisum sativum L.)

Summary The aim of this study was to determine whether DNA variations could be detected in regenerated pea plants. Two different genotypes were analyzed by cytogenetic and molecular techniques: the Dolce Provenza cultivar and the 5075 experimental line. Dolce Provenza regenerated plants showed a reduction in DNA content, particularly at the level of unique sequences and ribosomal genes. Moreover, regeneration was associated with an increase in DNA methylation of both internal and external cytosines of the CCG sequence. On the other hand, the DNA content of the 5075 line remained stable after regeneration. DNA reduction was found only in 5075 plants regenerated from callus cultures maintained for long incubation periods (about a year). The DNA variations observed are discussed both in relation to the genotype source and the role of tissue-culture stress.     

Use of15N/14N rations to evaluate the food source of the mysid,Neomysis intermedia Czerniawsky,in a eutrophic lake in Japan

The stable isotope ratios of nitrogen were measured in the mysid,Neomysis intermedia, together with various biogenic materials in a eutrophic lake, Lake Kasumigaura, in Japan throughout a year of 1984/85. The mysid, particulate organic matter (POM, mostly phytoplankton), and zooplankton showed a clear seasonal change in ¹⁵N with high values in spring and fall, but the surface bottom mud did not. A year to year variation as well as seasonal change in ¹⁵N was found in the mysid. The annual averages of ¹⁵N of each material collected in 1984/85 are as follows: surface bottom mud, 6.3 (range: 5.7–6.9); POM, 7.9 (5.8–11.8); large sized mysid, 11.6 (7.7–14.3); zooplankton, 12.5 (10.0–16.4); prawn, 13.2 (9.9–15.4); goby, 15.1 (13.8–16.7). The degree of¹⁵N enrichment by the mysid was determined as 3.2 by the laboratory rearing experiments. The apparent parallel relationship between the POM and the mysid in the temporal patterns of ¹⁵N with about 3 difference suggests the POM (mostly phytoplankton) as a possible food source ofN. intermedia in this lake through the year.     

Inspection and feeding of larvae by worker honey bees (Hymenoptera: Apidae): Effect of starvation and food quantity

Honey bee larvae are frequently inspected and, sometimes, provided with food by adult workers, but the stimuli that elicit the important task of food provisioning have never been investigated. Larvae with their food experimentally deprived received more frequent inspection and feeding visits from nurse bees than normally fed larvae, suggesting that there could be a hunger signal. Food-deprived larvae with artificially supplied larval food received the same rate of feeding visits from nurse bees as did normally fed larvae but still received more inspection visits. These results suggest that stimuli eliciting feeding are different from those for inspection. They also support the hypothesis that worker bees deposit food in a larval cell only when the quantity of food is below a certain minimum threshold that is perceived during larval inspections. A model is presented regarding the stimuli from larvae that result in worker feeding behavior.     

Ultrastructure of the pituitary gland (pars distalis) in sockeye salmon (Oncorhynchus nerka) during gonad maturation

Summary The fine structure of the various hormone-producing cell types (with the exclusion of the prolactin cells) in the pituitary gland (pars distalis) of migratory sockeye salmon is described. All fish were in an advanced stage of sexual maturation. In the proximal pars distalis five cell types were distinguished: growth hormone cells, ACTH cells, gonadotrops, vesicular cells, and chromophobe cells. Gonadotrops were also found throughout the rostral pars distalis. A conspicuous feature of the gonadotrops was the presence of two kinds of secretory inclusions: small electron-dense granules (200–375 m) and large, relatively electron-translucent globules (400–2 000 m). The large vesicular cells, so called because of their conspicuous vesicular endoplasmic reticulum, were numerous and often appeared to contain some small granules. It is argued that they may represent a second type of gonadotropic cell, which, in earlier stages of gonad development, contains many granules but becomes largely degranulated near the time of reproduction when the other gonadotrops (globular gonadotrops) abound. The chromophobes, which were smaller and far less abundant than the vesicular cells, also appeared to contain small granules (120–280 m). They are probably thyrotrops.The assistance of Mr. S. Killick, of the International Pacific Salmon Fisheries Commission, who helped in the collection of salmon, is gratefully acknowledged.     

The surface of Priapulus caudatus (Lamarck, 1816)

A scanning electron microscope study of the surface of Priapulus caudatus is presented. Both adults and larvae have been studied. The pharynx, circumoral region, collar, proboscis, trunk, caudal appendage, and larval lorica are described.     

Expression of the plant sulphite reductase in cell suspension cultures from Catharanthus roseus L.

Sulphur-heterotrophic growth exhibited a dual response to the expression of sulphate-assimilating enzymes. The level of ATP-sulphurylase (EC 2.7.7.4) appeared repressed while sulphite reductase (EC 1.8.7.1) and O-acetyl-l-serine sulphhydrylase (EC 4.2.99.8) were derepressed and coordinated in their occurrence. The capability of the cells to reduce adenylylphosphosulphate or 3-phospho adenylylphosphosulphate to cysteine coincided with the activity of sulphite reductase. The expression of these reducing steps lacked correlation with the regulation of ATP-sulphurylase.Abbreviations APS adenylylphosphosulphate - MVH reduced methylviologen - OAS O-acetyl-l-serine - PAPS 3-phospho adenylylphosulphate     

Acclimation of the Sea Cucumber Apostichopus japonicus to Decreased Salinity at the Blastula and Gastrula Stages: Its Effect on the Desalination Resistance of Larvae at Subsequent Stages of Development

Apostichopus (= Stichopus) japonicus blastulae and gastrulae were acclimated for 18 h to salinities of 32 (control), 24 and 22 (the lower limit of the range of tolerance), and 20 (below the range of tolerance). Acclimation to 20 resulted in the appearance of teratic larvae, most of which subsequently died. Acclimation to 24, 22, and 20 led to a shift in the range of tolerance of the larvae at further stages of development. With a decrease in salinity, acclimated larvae developed more successfully than unacclimated larvae. Acclimated larvae attained the pentactula stage and settled at a salinity range of 32–20; unacclimated larvae, at 32–22. At different stages of development, acclimated larvae survived greater decreases in salinity than unacclimated larvae. The acclimation effects could be traced up to metamorphosis and settling, i.e., two weeks after the end of the acclimation process.     

Polygonal inequalities as a key to neuronic equations

Neuronic or decision equations, first proposed as a mathematical model of neural activity, have shown, after their exact, compact solution was found, typical behaviours that make them natural tools for General Systems studies. It is shown here that their mathematical investigation is remarkably furthered by generalizing the triangular inequality to polygonal ones. These permit the immediate computation of the tensorial expansion of linearly separable boolean functions, and exhibit clearly the connection between their continuous and discontinuous aspects.     

Phenylacetic acid-induced somatic embryogenesis in cultured hypocotyl explants of geranium (Pelargonium x hortorum Bailey)

Summary The effect of a non-indole compound, phenylacetic acid (PAA), on the induction of somatic embryogenesis in tissue cultures of geranium (Pelargonium x hortorum Bailey cv. Scarlet Orbit Improved) was investigated. Hypocotyl explants derived from young, dark-grown seedlings were cultured on Murashige and Skoog (1962) medium (MS) supplemented with PAA or IAA (0.01–120 M) alone or in combination with BAP (8 M). Somatic embryogenesis was induced by both PAA and IAA at 0.01–20 M with 8 M BAP, however, the optima differed considerably for the two compounds. Maximal activity of IAA for somatic embryogenesis was found at 0.1–2.5 M, whereas PAA gave best results at 10 and 20 M under identical culture conditions. Higher concentrations (30–120 M) of IAA or PAA in the medium induced callusing in the explants, but the callus was neither embryogenic nor morphogenic.Abbreviations BAP N⁶-benzylaminopurine - IAA indole-3-acetic acid - MS Murashige and Skoog (1962) - PAA phenylacetic acid     

Carotenoid pigments in a red strain of Rhizobium from Lotononis bainesii Baker

The carotenoid pigments of a Rhizobium strain isolated from Lotononis bainesii were found to be diglucosyl-4,4-diapocarotene-4,4-dioate and glucosyl-4,4-diapocarotene-4-oate-4-oic acid.5th publication in the series Carotenoids of Rhizobia [4th publication: Helv. chim. Acta 62: 2551–2557 (1979)]     

Purification and immunocytochemical localization of kafirins inSorghum bicolor (L. Moench) endosperm

Summary Kafirins are the storage proteins of sorghum and are found in protein bodies in the seed endosperm. They have been classified as -, -, and -kafirins according to differences in molecular weight, solubility, and structure. The kafirins were purified, amino acid composition was determined, and immunolocalization methods were used to determine the organization of the protein bodies and distribution of kafirins throughout the endosperm. All three groups of kafirins were low in lysine. -Kafirins and -kafirins were relatively high in cysteine, and -kafirins were relatively high in methionine. Transmission electron microscopy showed that protein bodies in the peripheral endosperm were spheroid with concentric rings and few darkly stained inclusions. In contrast, protein bodies of the central endosperm were irregularly shaped with a higher proportion of darkly stained material. The light staining regions of the protein bodies are composed primarily of -kafirins with minor portions of - and -kafirins. The dark staining regions, however, are composed primarily of - and -kafirins. Immunoelectron microscopy showed that protein bodies in the peripheral endosperm contain predominantly a-kafirin with minor amounts of - and -kafirin. Central endosperm protein bodies are also predominantly -kafirin, but have a higher proportion of -kafirin and -kafirin than the peripheral endosperm protein bodies.Abbreviations GAR-HRP Goat anti-rabbit horseradish peroxidase - IgG immunoglobulin G - 2-ME 2-mercaptoethanol - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis - TBS Tris buffer saline - TBS-T Tris buffer saline with Tween - TBS-T-B Tris buffer saline with Tween and bovine serum albumin - TCA trichloroacetic acid - UV ultraviolet     

Über die Herkunft „synaptischer“ Bläschen in neurosekretorischen Axonen

Zusammenfassung In der Neurohypophyse fetaler und neugeborener Ratten entsteht die Mehrzahl der synaptischen Bläschen aus Erweiterungen der Neurotubuli. Ferner können pinocytotische Bläschen als synaptische Vesikel imponieren. Die Bläschenbildung aus Membranen von Elementargranula (vgl. Herlant, 1967) tritt dagegen in den Hintergrund. Ein Auftreten von Vesikeln im Innern von Elementargranula wurde nicht beobachtet.

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The origin of synaptic vesicles in neurosecretory axons

Summary In the neurohypophysis of fetal and newborn rats the majority of synaptic vesicles originate from dilatations of neurotubuli. Moreover, pinocytotic invaginations give rise to synaptic vesicles. Evaginations of elementary granule membranes, as described by Herlant (1967), are seldom to be found and do not seem to play an important role in the formation of synaptic vesicles. The occurrence of vesicles within elementary granules was not observed.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Steroid Polyols from the Far Eastern Starfish Henricia sanguinolenta and H. leviuscula leviuscula

Two new asterosaponins, (20R)-3-O--D-(2-O-methylxylopyranosyl)-24-propylcholest-4-ene-3,6,8,15,16,29-hexaol (sanguinoside A) and (20R,24S)-3-O--D-(2,3,4-tri-O-methylxylopyranosyl)-5-cholestane-3,4,6,8,15,24-hexaol (sanguinoside B), were isolated from two species of Pacific Far Eastern Starfish Henricia sanguinolenta and H. leviuscula leviuscula, collected in the Sea of Okhotsk. Both glycosides contain aglycones with pentahydroxysteroid nuclei of similar structures, which are substituted at the 3-hydroxy group with differently methylated -D-xylosyl residues. Sanguinoside A has an unusual structure of its aglycone side chain, whereas sanguinoside B has a unique permethylated carbohydrate chain. In addition, laevisculoside G, a known glycoside, was identified in the H. leviuscula starfish. The structures of the isolated glycosides were established by interpreting their spectral data and by comparing their spectral characteristics with those of known compounds.     

The temperature-dependent duration of development and parasitism of three cereal aphid parasitoids, Aphidius ervi, A. rhopalosiphi, and Praon volucre

Temperature dependencies were established for the egg-to-mummy and mummy-to-adult phases, for mummy mortality, and for parasitism of Aphidius ervi Haliday, Aphidius rhopalosiphi De Stefani-Perez, and Praon volucre (Haliday) (Hymenoptera, Aphidiidae), three parasitoids of Sitobion avenae (Fabricius) (Homoptera, Aphididae), at 8°C, 12°C, 16°C, 20°C, and 25°C on winter wheat (cv. Haven). A physiological model described temperature-dependent development over the full temperature range, whereas a linear model was fitted for data above 8°C and used to estimate the lower temperature thresholds and day-degrees (° D) required for development. The thresholds for A. ervi were 2.2°C for egg-mummy development and 6.6°C for mummy-adult development, those for A. rhopalosiphi were 4.5°C and 7.2°C, and those for P. volucre were 3.8°C and 5.5°C. The time to develop into mummies and adults differed significantly between the three species: A. ervi development into mummies required an average of 159 ° D, while development into adults took an average of 73 ° D. The corresponding average times required for A. rhopalosiphi and P. volucre to develop mummies were 124° D and 126° D, while their development into adults required an average of 70° D and 150° D, respectively. Mummy mortality was 25–35% at 8°C and less at the higher temperatures tested, but began to increase again at 25°C, showing a quadratic relationship between mortality and temperature. Parasitization was very low or, in the case of P. volucre, absent up to 12°C and thereafter increased with increasing temperature. The relationship between parasitization, recorded as percent aphids mummified, and temperature was linear at the temperatures tested and depended on species. A. ervisuperparasitized 11.1% aphids at 20°C and 16.6% aphids at 25°C, whereas superparasitism was low in A. rhopalosiphi and absent in P. volucre. From 16°C to 25°C the P. volucre sex ratio increased. For A. ervi and A. rhopalosiphi there was no trend with temperature, but at 20°C and 25°C it was close to even. Field data for 1996 and 1997 allowed for a comparison of actual and expected emergence of overwintering mummies. In both years, parasitoids were predicted to have emerged from overwintering mummies well in advance of the onset of aphid infestation, and more than a month earlier than the first parasitized aphids were found in winter wheat. Observations from trap plants in other crops supported the predictions of the models. Other factors that can affect biological control by cereal aphid parasitoids are discussed.     

Zum Feinbau des Komplexauges von Stylops spec. (Insecta,Strepsiptera)

Zusammenfassung Unter den Cornealinsen des Komplexauges von Stylops befindet sich ein Kristallkegel vom pseudoconen Typ, der von zahlreichen Pigmentzellen umhüllt wird. An seinem proximalen Ende liegen 6 meist pigmentfreie Zellen (Sempersche Zellen).Das Ommatidium besteht aus etwa 60 Retinulazellen. Ihre distal kranzartig miteinander verbundenen Mikrovillisäume bilden ein einziges offenes Rhabdom, das extrazelluläres (?) granuläres Material und die Basis der Semperschen Zellen umgibt. Stellenweise wird das Rhabdom samt granulärem Material von homogen erscheinenden distalen Ausläufern einzelner Retinulazellen überlagert. Proximad zerfällt das Rhabdom zunehmend in kleinere Rhabdomteile. Im zentralen Teil des Ommatidiums liegen 1–2 auffallend große Retinulazellen, die meist weniger elektronendicht erscheinen und kleinere Pigmentgrana haben.Die einzelnen Ommatidien werden von ungemein zahlreichen, sehr pigmentarmen Stützzellen umhüllt. Diese werden — wie die basalen Teile der Retinulazellen — teilweise durch Gliazellfortsätze isoliert.Bei Stylops, einem Vertreter der Strepsipteren, handelt es sich nicht um ocelläre Komplexaugen (Strohm, 1910), auch nicht um eucone Ommatidien (Kinzelbach, 1967), sondern um Ommatidien vom pseudoconen Typ. Zumindest der Bau des Rhabdoms ähnelt dem des Larvenauges (Stemma), dessen rezeptorischer Teil entgegen den Annahmen früherer Autoren in der Imago nicht reduziert wird.

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On the fine structure of the compound eye of Stylops spec. (Insecta, Strepsiptera)

Summary In the compound eye of Stylops a crystalline cone of the pseudocone type is found beneath the corneal lens. It is enveloped by several pigment cells. At the proximal part of the cone there are 6 cells (Semper cells) mostly pigment-free.The ommatidium consists of approximately 60 retinula cells. Their rhabdomeres distally rim-like connected to another form a single open rhabdom which encircles extracellular granular material as well as the bases of the Semper cells. Here and there the rhabdom plus granular material is overlain with distal protrusions of single retinula cells which appear to be homogeneous. Towards the proximal part the rhabdom increasingly divides up into smaller rhabdomal segments. One or two conspicuous large retinula cells were found in the central part of the ommatidium, appearing to be less electron-dense and containing pigment granules of a smaller size. Each ommatidium is surrounded by numerous cells (Stützzellen) lacking in pigment. These cells are partially insulated from another—as well as the basal parts of retinula cells—by protrusions of glia cells.Our investigations show that the eyes of Stylops (as a representative of Strepsiptera) are not of the ocellar complex eye type. At least the structure of the rhabdom resembles to that of the larval eye (stemma), the receptor part of which is not reduced in the imago.

Herrn Prof. Dr. Helmcke danke ich für die freundliche Unterstützung am Raster-Elektronenmikroskop.     

2-Hydroxyglutaryl-CoA dehydratase from Fusobacterium nucleatum (subsp. nucleatum): an iron-sulfur flavoprotein

Anaerobically prepared cell-free extracts from Fusobacterium nucleatum contain 2-hydroxyglutaryl-CoA dehydratase with a specific activity of 20 nkat mg^-1. The enzyme was purified 24-fold to a specific activity of 480 nkat mg^-1 by anion exchange chromatography, gel filtration and chromatography on Blue-Sepharose. The activity of the purified enzyme was strictly dependent on the reductant Ti(III)citrate and stimulated 25-fold by 0.15 mM ATP and 5 mM MgCl₂. ATP is hydrolysed to ADP during incubation with 2-hydroxyglutaryl-CoA dehydratase in the presence or absence of the substrate. The enzyme is extremely sensitive towards oxygen and is inhibited by 10 M chloramphenicol, 10 M 2,4-dinitrophenol or 0.15 mM hydroxylamine. The pure enzyme consists of three subunits (49 kDa), (39 kDa) and (24 kDa) in approximately equal amounts. In this respect the enzyme differs from the related 2-hydroxy-glutaryl-CoA dehydratase from Acidaminococcus fermentans and lactyl-CoA dehydratase from Clostridium propionicum both of which are composed of only two subunits with sizes comparable to those of and but require an additional protein for activity. The relative molecular mass of the native enzyme of about 100 kDa suggests a trimeric -structure. The homogeneous enzyme contains riboflavin (0.5 mol/112 kDa), iron and sulfur (3.5 mol/112 kDa each). Polyclonal antibodies directed against the 2-hydroxyglutaryl-CoA dehydratase from A. fermentans did not crossreact with cell free extracts or purified dehydratase from F. nucleatum. A comparison of the N-terminal amino acid sequences of the dehydratase subunits from A. fermentans and F. nucleatum, however, showed some similarities in the -subunits.Non-standard abbreviations DTT dithiothreitol - PAGE polyaccrylamide gel electrophoresis - VIS visible