Control of growth and differentiation of the wing imaginal disk of Precis coenia (Lepidoptera: Nymphalidae)

During the last larval instar, the wing imaginal disks of Precis coenia grow continuously. The rate of disk growth is not disk-autonomous but closely matches the rate of somatic growth of the larva, so that the size of the disks is a function of the size of the body, irrespective of the growth rate of the larva. When larvae are starved, their wing disks cease growth within 4 h, which indicates the existence of an efficient coupling mechanism between the growth of the soma and growth of the imaginal disks. Disk growth is inhibited by juvenile hormone in a dose-dependent manner. In the presence of the hormone the wing disks stop growing even while the larva continues to grow normally. During the last larval instar the wing imaginal disks also undergo a complex differentiation, consisting of the development of the lacunae and tracheation that define the future adult wing venation system. In normally growing larvae, differentiation of the wing disk is tightly correlated with wing size. Differentiation and size can be dissociated by starvation. If larvae are starved at any time after differentiation has begun, differentiation continues at a normal rate, even though the wing disk does not grow. Differentiation does not begin spontaneously in larvae that are starved before differentiation has begun. These findings indicate that the initiation of differentiation and its continuation are controlled independently. Juvenile hormone inhibits differentiation in a dose-dependent manner. Upon treatment with juvenile hormone, the stage of differentiation becomes fixed. These findings indicate that continued differentiation of the wing disk can only occur in the absence of juvenile hormone. Although the circulating level of juvenile hormone may be elevated during starvation, it is unlikely that this elevation is responsible for the observed effect of starvation on growth and differentiation of the disk.     

Effects of ecdysone and juvenile hormone on DNA metabolism of imaginal disks of Drosophila melanogaster

Imaginal disks of Drosophila melanogaster isolated en masse and incubated in Robb's tissue culture medium incorporate ³H-thymidine into nuclear DNA. Both α- and β-ecdysone stimulate the rate of ³H-thymidine incorporation into disk DNA. Concentrations of ecdysone that induce complete evagination of disks in vitro cause the initiation of DNA synthesis in some disk cells. Juvenile hormone has no effect on DNA synthesis in control disks. However, juvenile hormone blocks the ecdysone stimulation of DNA synthesis. It is proposed that juvenile hormone and ecdysone act in a balanced fashion to regulate DNA synthesis in imaginal disks.     

Intercellular junctions during development and in tissue cultures ofDrosophila melanogaster: An electron-microscopic study

Summary The present investigation analyzes intercellular junctions in tissues with different developmental capacities. The distribution of junctions was studied inDrosophila embryos, in imaginal disks, and in cultures of disk cells that were no longer able to differentiate any specific pattern of the adult epidermis.The first junctions —primitive desmosomes andclose membrane appositions — already appear in blastoderm.Gap junctions are first detected in early gastrulae and later become more and more frequent.Zonulae adhaerentes are formed around 6 h after fertilization, whileseptate junctions appear in the ectoderm of 10-h-old embryos.Inwing disks of all stages studied (22–120 h), three types of junctions are found: zonulae adhaereentes, gap junctions, and septate junctions. Gap junctions, which are rare and small at 22 h, increase in number and size during larval development. The other types of junctions are found between all cells of a wing disk throughout development.All types of junctions that are found in normal wing disks are also present in theimaginal disk tissues cultured in vivo for some 15 years and in thevesicles of imaginal disk cells grown in embryonic primary cultures in vitro. However, gap junctions are smaller and in the vesicles less frequent than in wing disks of mature larvae.Thus gap junctions, which allow small molecules to pass between the cells they connect, are present in the early embryo, when the first developmental decisions take place, and in all imaginal disk tissues studied, irrespective of whether or not these are capable of forming normal patterns.     

Control of pupal commitment in the imaginal disks of Precis coenia (Lepidoptera: Nymphalidae)

When final (5th) instar larvae of Precis coenia were treated with the juvenile hormone analog (JHA) methoprene, they underwent a supernumerary larval molt, except for certain regions of their imaginal disks, which deposited a normal pupal cuticle. Evidently those regions had already become irreversibly committed to pupal development at the time JHA was applied. By applying JHA at successively later times in the instar, the progression of pupal commitment could be studied. Pupal commitment in the proboscis, antenna, eye, leg and wing imaginal disks occurred in disk-specific patterns. In each imaginal disk there were distinct initiation sites where pupal commitment began during the first few hours of the final larval instar, and from which commitment spread across the remainder of the disk over a 2- to 3-day period. The initiation sites were not always located in homologous regions of the various disks. As a rule, pupal commitment also spread from imaginal disk tissue to surrounding epidermal tissue. The regions of pupal commitment in all disks except those of the wings, coincided with the regions of growth of the disk. Only portions of the disk that had undergone cell division and growth underwent pupal commitment. Shortening the growth period did not prevent pupal commitment in the wing imaginal disk, indicating that, in this disk at least, a normal number of cell divisions was not crucial in reprogramming of disk cells for pupal cuticle synthesis. The apparent growth spurt of imaginal disks that occurs during the last part of the final larval instar is merely the final stage of normal and constant exponential growth. Juvenile hormone (JH) and ecdysteroids appeared to play little role in the regulation of normal imaginal disk growth. Instead, growth of the disks may be under intrinsic control. Interestingly, even though endogenous fluctuation in JH titers do not affect imaginal disk growth, exogenous JHA proved able to inhibit both pupal commitment, cell movement, and growth of the disks during the last larval instar. This function of JH could be important under certain adverse conditions, such as when metamorphosis is delayed in favor of a supernumerary larval molt.     

The control of growth and differentiation of the wing imaginal disks of Manduca sexta

During the larval feeding period, the growth of the wing imaginal disks of Lepidoptera is dependent on continuous feeding. Feeding and nutrition exert their effect via the secretion of bombyxin, the lepidopteran insulin-like hormone. When larvae stop feeding and enter the wandering stage in preparation for metamorphosis, the control of imaginal disk growth becomes feeding and nutrition-independent. Growth of the wing imaginal disks of non-feeding wandering stage Manduca sexta can be stopped by removal of the brain, indicating that a brain-derived factor is required for continued disk growth. Isolated wing disk growth in vitro requires both 20-hydroxyecdysone (20E) and either brain extract or bombyxin to achieve normal growth. In vitro, brain extracts and synthetic bombyxin have little or no effect in stimulating disk growth, but they greatly enhance the effect of 20E, indicating that 20E and bombyxin act synergistically to modulate growth of the imaginal disk. Brain extract and bombyxin induce a suite of insulin-response events in cultured wing disks, which indicate that bombyxin and 20E act through separate and synergistic pathways. The dose-response to 20E reaches a plateau at about 0.1 microg/ml. Tracheal differentiation of the wing disks can be induced to initiate in vitro by a low concentration of 20E, whereas higher concentrations of 20E only stimulate growth.     

Morphologische Studie über den Reissnerschen Faden bei niederen Wirbeltieren

Zusammenfassung Die licht- und elektronenmikroskopische Untersuchung des Reissnerschen Fadens bei Pristella riddlei Meek und Larven von Salamandra salamandra terrestris zeigt im gesamten Verlauf des Reissnerschen Fadens Anlagerungen von Zelldetritus. Durch diese Beobachtung wird Olssons Theorie einer Transportfunktion des Reissnerschen Fadens gestützt.

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Summary In a light and electron microscope study on Reissner's fibre of Pristella riddlei Meek and larvae of Salamandra salamandra terrestris it is shown, that there are appositions of cell detritus in the whole length of Reissner's fibre. This observation supports Olsson's theory of a transport function of Reissner's fibre.

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Großenteils im Institut für Histologie und experimentelle Biologie der Universität München (Direktor: Professor Dr. med. R. Bachmann) und mit Unterstützung durch die Deutsche Forschungsgemeinschaft durchgeführt.     

Über den Feinbau der Duftdrüsen von Heteropteren

The scent-production and the scent-delivery in the posterior larval gland of the cotton bug Dysdercus intermedius Dist. was explored by means of light microscopy and electron microscopy.

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Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft.

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Herrn Prof. Dr. R. Danneel danke ich für beratende Hilfe. Für die Anfertigung der elektronenmikroskopischen Aufnahmen stellte mir freundlicherweise Herr Prof. Dr. E. Scholtyseck das Mikroskop Zeiss EM 9A zur Verfügung. Fräulein Karin Wenzelmann und Fräulein Barbara Vogt danke ich für technische Assistenz.

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Herrn Prof. Dr. Dr. R. Lermensick zum 70. Geburtstag gewidmet.     

The assay of ecdysones and juvenile hormones on Drosophila imaginal disks in vitro

Evagination of mass-isolated imaginal disks of Drosophila melanogaster is induced in vitro by ecdysones (α- and β-ecdysone, inokosterone, cyasterone, rubrosterone) and inhibited by juvenile hormones (Law's compound, C₁₇ and C₁₈ Cecropia hormones, farnesol). It was found that disks do not metabolize α- or β-ecdysone. A concentration of β-ecdysone of 0·1 μg/ml or of α-ecdysone of 20 μg/ml was needed to induce complete evagination. Thus, β-ecdysone is about two hundred times more active than α-ecdysone. It is suggested that β-ecdysone is responsible for in situ moulting hormone activity in Drosophila.     

Die Verwendung der Imaginalscheiben zur Bestimmung des Entwicklungszustandes von Chironomus-larven (Dipt.)

Imaginal disks and the gonads of Ch. thummi have been used to obtain clear criteria for the determination of the developmental stage of 4th instar larvae. The imaginal anlagen are growing continuously and the established developmental phases are representing equal intervals of time.

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Mit Unterstiitzung der Deutschen Forschungsgemeinschaft.

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Die Arbeit wurde Herrn Prof. Dr. W. Kuhl zum 75. Geburtstag gewidmet.     

Das nervensystem der cercarie von Catatropis indica srivastava, 1935 (Digenea : Notocotylidae) und der geschlechtsreifen form von Diaschistorchis multitesticularis Rohde, 1962 (Digenea : Pronocephalidae)

The nervous systems of the cercaria of Catatropis indica and of the adult Diaschistorchis multitesticularis are described. Ganglion cells, myoblasts and large cells of unknown nature in Diaschistorchis are described and figured.

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Für technische Hilfe danke ich Miss Lilian Liz, Mr. Teh Kox Leng und Mr. K. Balakrishnan. Durchgeführt im Zoology Department, University of Malaya, Kuala Lumpur, mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Formation of chimeric patterns and segregation of cells in varied combinations of thorax forming imaginai disks ofDrosophila melanogaster

Summary Genetically marked thoracic imaginal disks ofDrosophila melanogaster were partially dissociated and reaggregated. After metamorphosis, combinations of dorsal proand mesothoracic disks gave rise to mosaics, whereas no such mosaics were formed in combinations of dorsal meso- and metathoracic disks. Adventitious bristles are formed by the metathoracic disk, but these were never integrated in a common pattern with mesothoracic bristles.     

Autoradiographische Untersuchungen des Transportes einiger Nahrungsbestandteile im Darmtrakt zweier Kleinzikaden: Euscelidius variegatus Kbm. (Jassidae) und Triecphora vulnerata Germ. (Cercopidae)

Zusammenfassung Durch Verfütterung von radioaktiv markierten Nahrungsbestandteilen, geboten in synthetischer Nährlösung, wird die Richtigkeit der Hypothese von Berlese (1909) und Licent (1913) über die Funktion der Filterkammer für Euscelidius variegatus (Jassidae) und Triecphora vulnerata (Cercopidae) bewiesen. Während Wasser und Saccharose bzw. deren Spaltprodukte zum großen Teil die Filterepithelien passieren, in den Enddarm gelangen und als Honigtau vorzeitig ausgeschieden werden, verbleiben Aminosäuren und Protein im Verdauungstrakt. Eine Art Druckfiltration in der Filterkammer wird vermutet, da sich keine Hinweise für einen aktiven Transport durch die Filterepithelien erkennen lassen.

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Autoradiographic experiments on the transport of some nutritional elements in the digestive tract of two leafhoppers: Euscelidius variegatus Kbm. (Jassidae) and Triecphora vulnerata Germ. (Cercopidae)

Summary By feeding of radioactive nutritional elements in a synthetic diet the hypothesis of Berlese (1909) and Licent (1913) is proved for Euscelidius variegatus (Jassidae) and Triecphora vulnerata (Cercopidae). Most of the water and the sucrose or its monosaccharides pass the filter epithelia, reach the hind gut immediately and are defecated precociously as honey dew. Amino acids and protein on the other hand remain in the digestive tract. Some sort of filtration by pressure in the filter chamber is to be supposed as there are no hints on an active transport through the filter epithelia.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Über das Osphradium der prosobranchen SchneckenBuccinum undatum L. undNeptunea antiqua (L.)

Zusammenfassung Die komplizierten, bipektinaten Osphradien der NeogastropodenBuccinum undatum undNeptunea antiqua sind durch folgende Zelltypen gekennzeichnet: Die hochprismatischen Stützzellen stellen den Hauptteil des mehrreihigen Osphradialepithels und sind durch ein reich ausgebildetes Villussystem sowie zahlreiche Pigmentgranula charakterisiert. Bisweilen tragen sie Zilien. Mindestens zwei Schleimzelltypen lassen sich unterscheiden. Den verschiedenen Sinneszelltypen lassen sich zwei Funktionen zuordnen: der Chemorezeption und dem Tastsinn. Die Funktion eines weiteren Typs mit stark ausgebildetem glattem endoplasmatischem Reticulum bleibt unbekannt.

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The osphradium of the prosobranch gastropods Buccinum undatum L. and Neptunea antiqua (L.)

Summary The complicated, bipectinate osphradia of the NeogastropodsBuccinum undatum andNeptunea antiqua are characterized by the following cell types: The columnar supporting cells of the pseudostratified epithelium form the bulk of the epithelial cells and exhibit a profusely developed system of microvilli and an abundance of pigment granules. Occasionaly they are ciliated. At least two types of mucous cells can be distinguished. The different types of sensory cells can be associated with two functions: chemoreception and touch appreciation. An additional sensory cell type with a well developed system of smooth endoplasmic reticulum cannot be related to any particular function.

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Die Untersuchungen wurden mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft durchgeführt.

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Herrn Prof. Dr.A. Kaestner (München) danken wir für Literaturhinweise.

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Herrn Prof. Dr.W. Bargmann danke ich für einen Arbeitsplatz im elektronenmikroskopischen Laboratorium des Anatomischen Instituts Kiel.     

Über den Feinbau der wachsenden Megaspore vonSelaginella

Zusammenfassung Im Gegensatz zu den ErgebnissenFittings (1900) ist das Cytoplasma derSelaginella- Megaspore nicht vom wachsenden Sporoderm getrennt. DieSelaginella-Megaspore stellt demnach kein Beispiel für Zellwandwachstum ohne Kontakt mit dem Plasmalemma dar. Die Elemente der Exine anastomosieren. Die Sexine hat eine schwammartige Struktur und eine warzige und kurzstachelige Skulptur. Abgesehen vom proximalen Pol, wo zwischen Sexine und Nexine eine solide Sporopolleninschicht liegt, entsteht im inneren Teil der Sexine in einem frühen Entwicklungsstadium ein breiter, artifizieller Spalt. Die Nexine besteht auf 7–13 Lamellen. Ihre dünnsten Stellen haben eine Dimension von 13 nm. Vor allem zwischen den Lamellen der Nexine liegt eine fibrillär-netzförmige Matrix mit verschieden großen, dunkel kontrastierten Granula.

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On the ultrastructure of the growing megaspore ofSelaginella

Summary In contrary to the results ofFitting (1900) the cytoplasm of theSelaginella- megaspore is not separated from the growing sporoderm. Therefore theSelaginella- megaspore is not an example for cell wall growth without contact with the plasmamembrane. The elements of the exine anastomose. The sexine has a spongy structure and a verrucate and spinulous sculpture. Apart from the proximal pole, where a solid layer of sporopollenin lies between sexine and nexine, in the inner part of the sexine in an early developmental stage a broad artificial cleft originates. The nexine consists of 7–13 lamellae. Their thinnest parts show a dimension of 13 nm. Mainly between the lamellae of the nexine a fibrillar-netlike matrix with darkly contrasted granula of different size is situated.

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Herrn Prof. Dr.Walter Schumacher zum 70. Geburtstag.

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FrauChrista Grabert danken wir für sorgfältige Präparation, der Deutschen Forschungsgemeinschaft für eine Sachbeihilfe. Das Siemens-Elmiskop I A stellte die Stiftung Volkswagenwerk zur Verfügung.     

Kritische Bemerkungen zuPapaver bracteatum Lindl.

Zusammenfassung Form und Behaarung des Kelches und die Farbe der Kronblätter werden als wichtigste diagnostische Merkmale vonPapaver bracteatum Lindl. beschrieben. Sie erlauben dessen eindeutige Unterscheidung von verwandten Taxa. Dagegen sind die Brakteen, denen in der Literatur große Aufmerksamkeit geschenkt wird, für eine Trennung ungeeignet.

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Summary Shape and pubescence of calyx and colour of petals are described as important diagnostic characters ofPapaver bracteatum Lindl. They allow a correct separation from related taxa. In contrast to the view found in literature the bracts are not essential to discrimination.

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Wir danken Herrn Prof. Dr. K.Mothes herzlich für sein Interesse am Fortgang unserer Untersuchungen und Herrn Dr. K.Werner vom Institut für Systematische Botanik und Pflanzengeographie der Universität Halle für kritische Diskussionen bei der Abfassung des Manuskriptes.     

Zur Wirkung des Lichts auf das Ruhepotential der grünen Pflanzenzelle

Summary Through an actionspectrum it has been shown that light affects the membrane potential of the alga Acetabularia crenulata by way of the chloroplasts.

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Herr cand. rer. nat. Dietrich Gradmann hatte in Form einer Zulassungsarbeit für das Staatsexamen wesentlichen Anteil an den Experimenten. Herrn Prof. Dr. E. Bünning danken wir für die großzügige Unterstützung der Arbeit.     

Zur Ultrastruktur der Riesenpiastiden aus dem Palisadenparenchym vonPeperomia metallica Lind et Rodig

Summary The one layered palisade parenchyma ofPeperomia metallica contains giant chloroplasts, 20–25 m in size. The ultrastructure of these organelles is discussed in relation to their function.

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Herrn Prof. Dr. E.Müller danke ich für die Anregung zu dieser Arbeit.     

Beitrag zur Phytochemie der Hepaticae

Zusammenfassung In sauren methanolischen Extrakten aus gametophytischem Gewebe vonLophocolea bidentata (L.)Dum. undPlagiochila asplenioides (L.)Dum. konnte zum ersten Male Ellagsäure mit Hilfe dünnschichtchromatographischer Methoden identifiziert werden. Daneben fanden sich in den Extrakten noch einige andere bisher noch nicht identifizierte Phenole, darunter möglicherweise 8 Flavonoide.

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Summary Ellagic acid was detected in acidic methanol-extracts of gametophytic tissue ofLophocolea bidentata (L.)Dum. andPlagiochila asplenioides (L.)Dum. The identification was accomplished by thin-layer Chromatographic methods. Beside this compound some more still unidentified phenolics were found, among those probably 8 flavonoids.

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Herrn Prof. Dr. L.Brauner, mit den herzlichsten Wünschen zum 75. Geburtstag gewidmet.

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Herrn Prof. Dr. H.Jork von der Fachrichtung Pharmakognosie und Analytische Phytochemie sowie Fräulein S.Klein danken wir sehr für die Hilfe bei der Herstellung der UV-Spektren. Herrn grad. biol. et chem. S.Bartl danken wir für hilfreiche Diskussion.     

Survival of Cronartium ribicola on a medium containing host tissue culture diffusates

Vegetative mycelia ofCronartium ribicola J. C. Fisch. exRabenh. that were removed from media surrounding infected pine host tissue cultures did not survive when transplanted to a defined artificial medium. Similar mycelia retained on a medium that had formerly supported pine host tissue cultures did survive for periods up to 120 days. These mycelia were fully capable of reinfecting healthy host tissue cultures.

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Zusammenfassung Vegetative Myzelien vonCronartium ribicola J. C. Fisch. exRabenh., die von Nährmedien, die die Gewebskultur des infizierten Kiefernwirtes umgeben, entfernt worden sind, überlebten nicht, wenn sie auf einen definierten, künstlichen Nährboden übertragen worden sind. Ähnliche Myzelien auf einem Nährboden gehalten, der vorher Kiefer-Gewebskultur getragen hat, überlebten für eine Periode bis zu 120 Tagen. Diese Myzelien waren fähig, gesunde Wirtsgewebekulturen wiederum zu infizieren.

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stationed in Moscow, Idaho, at Forestry Sciences Laboratory, maintained in cooperation with the University of Idaho.     

Effects of beta-ecdysone and juvenile hormone on the Na+/K+-dependent ATPase in imaginal disks of Drosophila melanogaster.

The evagination of imaginal disks of Drosophila melanogaster is induced in vitro by β-ecdysone and inhibited by juvenile hormone. The possibility that these hormones act by changing intracellular Na⁺ and K⁺ levels was investigated by studying their effects on the sodium-potassium dependent adenosinetriphosphatase (NaK ATPase), an enzyme with a major rôle in regulating Na⁺ and K⁺ levels in cells. We find that β-ecdysone has no effect on this enzyme and can induce evagination even when intracellular Na⁺ concentrations are increased 2 to 3 fold by ouabain. Juvenile hormone stimulates the enzyme, but still acts to inhibit evagination when NaK ATPase activity is inhibited by ouabain. We conclude that the actions of β-ecdysone and juvenile hormone on imaginal disk evagination do not directly involve the NaK ATPase or require specific changes in Na⁺ and K⁺ concentrations.