Clonal analysis of the blastoderm anlage of the Malpighian tubules in Drosophila melanogaster

Summary Genetically marked maroon-like (mal) clones were induced by mitotic recombination with X-rays at the blastoderm stage in mal/mal ⁺ heterozygotes and were analysed in differentiated Malpighian tubules (MT). Marked cells were not confined to single anterior (MA) or posterior (MP) tubules, but were distributed among the four tubules. About 70% of the clones with two or more cells were fragmented, i.e. mal cells were separated by wild-type cells. Since the clones contain, on average, 6 cells and the differentiated MT consist of 484 cells (2 × 136 MA cells, 2 × 106 MP cells), we estimate that there are about 80 cells in the blastoderm anlage which on average pass through two to three mitoses. With increasing radiation doses (254 R, 635 R, 1270 R) a linear increase in clone frequency is observed. The mean sizes and size distributions of clones, however, remain unchanged. Since the increasing radiation dose also results in fewer differentiated Malpighi cells, we assume that regeneration does not occur. Therefore, size distributions of marked clones presumably represent real mitotic patterns in normogenesis. We suggest that essentially three successive mitoses take place, with a decreasing fraction of cells showing mitotic activity. Only a small fraction of cells goes through a fourth or even a fifth mitosis. Marked non-Minute clones induced in Minute heterozygotes are more frequent, but are not larger than non-Minute clones in wild-type background. Therefore, compartment boundaries cannot be recognized by this method. However, frequencies of marked cells found simultaneously in MA and MP pairs or in several single tubules of the same individuals are significantly higher than frequencies of multiple recombination events predicted by the Poisson distribution. From this, we conclude that neither the MA pair nor the MP pair nor single tubules represent compartments of the MT anlage.On the occasion of his 60th birthday, this work is dedicated to Prof. Dr. H.J. Becker, who initiated cell lineage studies in Drosophila     

Molecular-genetic mechanisms for the functionally determined isogene selections in muscle

In embryonic development, differentiation consists in the modification of a fraction of the genes into a form irreversibly blocked from expression. In fetal development, there are further differentiation phenomena, often representing the selective expression of isogenes or members of a gene family. These subdifferentiations are reversibly determined by functional influences exerted by the nervous system and by hormones. The myosin heavy-chain (MHC) isogene family is a favorable case for such studies. In skeletal muscle, the MHC type is regulated by the innervation determining the myonal types slow (S) and fast (F). In the heart, the isoforms MHC and are regulated by thyroid hormone (TH). The details depend on the species. While TH always promotes , the euthyroid state can be either or , the latter being the rule. In skeletal S and F types, the reversibility of regulation is demonstrated by the nerve-crossing experiment, which causes a reciprocal SF and FS reprogramming; this requires months, even years to be completed. Such reprogrammings are pleiotropic, affecting a number of type characteristics, which eventually reach a new functional harmony. Ongoing work is described on the question of whether the nerve communicates its influence by impulse patterns or by determinant substances.     

The nephridia of the interstitial polychaete Hesionides arenaria and their phylogenetic significance (Polychaeta,Hesionidae)

Summary The small hesionid polychaete Hesionides arenaria possesses paired segmental excretory organs that closely resemble solenocytic protonephridia. The nephridium consists of one terminal cell and four tubule cells which form the emission channel. From the terminal cell, up to six flagella arise each surrounded by a weir of ten regularly arranged cytoplasmic rods. The structure of the cytoplasm of three of the following cells suggests that they function in active transport and storage. Because all of the larger, more primitive species of this family are equipped with metanephridia, the possibility is discussed that these organs have been developed out of metanephridia. The Hesionides arenaria nephridium may be a morphological stage in the evolutionary pathway from metanephridia to solenocytes. This would mean that solenocytes can no longer be considered to be homologous in every case with other protonephridial organs in polychaetes and may well be derived several times independently out of metanephridia or true protonephridia.     

The heat labile phosphatase modulator (inhibitor-2) complex from rabbit skeletal muscle

The heat stable phosphatase modulator protein (inhibitor-2) has been shown to play a crucial role in the reversible ATP, Mg-dependent activation of a multisubstrate protein phosphatase. The modulator activity is acid and heat stable and resides in a small asymmetrical protein which, after boiling migrates in sucrose density gradient centrifugation with a molecular weight of 17K. The present report shows that in unboiled rabbit skeletal muscle preparations all the modulator activity is found associated with a heat labile protein component, which imposes an important regulatory feature on the heat stable activity. The heat labile complex migrates in sucrose density gradient centrifugation as a M_r = 70K protein.     

Untersuchungen über die Jahresrhythmik von Laufkäfern (Coleoptera,Carabidae) in der Cyrenaika (Libyen,Nordafrika)

Summary In a 30 km deep coastal area of the Cyrenaika (Libya) a total of 28 species of carabids was collected on regular excursions in 1967 and 1968. In midsummer almost no carabids were caught. They appeared at the beginning of autumn and were caught in winter regularly in equal numbers. During March, April and May the number of catches increased considerably. Using ground traps no more than two species (Carterus silvestrii, Pristonychus picicornis) were caught and that only from December to May. From the pattern of their occurrence we can conclude that in the Cyrenaika carabid beetles propagate mainly during the winter.By examining the gonads, catching larvae and breeding, it was possible to prove that the speciesBroscus laevigatus, Harpalus litigiosus ssp.cyrenaicus andPristonychus picicornis propagate in winter. Examination of the gonads also indicates a winter propagation of the speciesPterostichus barbarus andLaemostenus complanatus ssp.cyrenaicus. It is not certain, however, thatCarterus silvestrii propagates during the winter.The speciesCalathus fuscipes andCalathus mollis from the temperate northern regions, which are known as autumn breeders, were caught in Libya too, which indicates a relation between the autumn breeders of Middle and Northern Europe and the winter breeders of the South Mediterranean countries. The presence ofPogonus chalceus in Libya strongly suggests that, in certain biotopes, spring breeders may develop besides the dominant autumn breeders.     

Autonome Determination für Pigmentbildung beimwhite-Positionseffekt vonDrosophila melanogaster

Zusammenfassung Beimwhite-Positionseffekt vonDrosophila melanogaster findet die Determination für Pigmentbildungspotenzen der Augenzellen am Ende des ersten Larvenstadiums statt. Augenimaginalscheiben wurden vor oder nach diesem Zeitpunkt zusammen mit möglichst wenig larvalem Gewebe aus Larven entnommen und in die Abdomina adulter Weibchen transplantiert. Nach einer Kultivierungsdauer von 5–7 Tagen wurden die Implantate in Larven rücktransplantiert, mit denen sie die Metamorphose durchliefen. Es konnte gezeigt werden, daß die Augenanlagezellen auch während der Kultivierungsperiode im Adultabdomen autonom determiniert werden. Ein Einfluß mittransplantierten Larvalgewebes auf die Determination konnte nicht nachgewiesen werden. Dieser Determinationsvorgang ist daher sehr wahrscheinlich unabhängig vom spezifischen Larvalmilieu.

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Autonomous determination for pigment formation inwhite position-effect ofDrosophila melanogaster

Summary Inwhite position-effect ofDrosophila melanogaster, determination for the potential of pigment formation of eye cells takes place at the end of the first larval instar. Eye discs, prior to or after this developmental stage, were transplanted together with some larval tissue into the abdomens of adult females. After a cultivation period of 5 to 7 days, the implants were transplanted back into larvae. Imaginal differentiation occurred in these metamorphosing hosts. It could be shown that eye disc cells become autonomously determined during the cultivation period. An influence of the larval tissues transplanted together with the eye discs on determination could not be demonstrated. Therefore, this determinative event most likely is independent on the specific larval milieu.

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Die Arbeit wurde durch ein Stipendium der Deutschen Forschungsgemeinschaft gefördert. Prof. Dr. E. Hadorn danke ich sehr für die Möglichkeit, die Untersuchung in Zürich durchzuführen; ihm sowie Dr. G. Mindek bin ich dankbar für anregende Diskussion, Dr. A. Dübendorfer für die Einführung in die Technik.     

Pollenanalytischer Nachweis eines Schwermetallrasens in Wales

Zusammenfassung Ein kupferreiches Moor bei Dolfrwynog in Wales wurde pollenanalytisch untersucht. Auf ihm gedeiht ein Schwermetallrasen, der durch Cu-resistente Populationen von Armeria und Minuartia gekennzeichnet. ist. Auf Grund der pollenanalytischen Befunde kann diese Gesellschaft bis etwa 1100 n. Chr. zurückverfolgt werden. Ausbreitung und Entwicklung der Schwermetallpflanzen werden im gesamten Profil stark von anthropozoogenen Faktoren beeinflußt. Doch hat erst die bergbauliche Nutzung des Moores zum fast vollständigen Verschwinden der Schwermetallpflanzen geführt.

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Summary On a copper turf of Dolfrwynog in Wales there is growing a heavy metal plant community, characterized by copper-resistent populations of Armeria maritima and Minuartia verna. A pollenanalytical research of the deposit has shown that this community is existing since the 12^th century. Comparison with the general vegetation development in this area represents that expansion and development of the heavy metal plants seemed to be determined by anthropozoological factors and correlated with their change. However, the intensive mining of the copper-turf caused a sharp decrease in the frequency of these species.

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Résumé Sur un marécage riche en cuivre aux environs de Dolfrwynog dans le pays de Galles il y a une association des plantes métallorésistantes, caractérisée par Armeria maritima et Minuartia verna. Dans une étude pollen-analytique on peut constater que les plantes métallorésistantes existent ici déjà du 12^e siècle, au moins. Depuis ce temps-là, des facteurs anthropozoogènes ont exercé une influence énorme sur l'expansion et sur le développement d'Armeria et de Minuartia. Mais, premièrement depuis 1810, l'exploitation des sols riches en cuivre a mis en danger l'existence de ces plantes métallorésistantes.

     

Versuche zur Schlüpfrhythmik bei Carabiden

Zusammenfassung Die Schlüpfzeiten der Laufkäferarten Agonum assimile Payk., Pterostichus angustatus Dft., Pterostichus nigrita F. und Pterostichus oblongopunctatus F. wurden in 18/6 h-Langtag registriert.Zur Registrierung wurde eine Kamera mit automatischer Auslösesteuerung verwandt.Die Aufnahmen erfolgten in einer Versuchsserie mit Blitzlicht, in einer zweiten Serie nur während der Hellphase beim Licht von Leuchtstoffröhren, wie sie auch zur Beleuchtung des Zuchtraumes dienten.Beide Versuchsserien ergaben keinen Hinweis auf eine typische Schlüpfrhythmik bei den vier Laufkäferarten. Pro Stunde der Hellphase schlüpfen jedoch bei allen Arten etwas mehr Käfer als pro Stunde der Dunkelphase. Dieser Unterschied ließ sich nur für P. angustatus statistisch sichern. Daraus läßt sich auf eine latente Bereitschaft zur Synchronisation des Schlüpfens durch den Licht-Dunkel-Wechsel bei manchen Carabiden schließen.Die Geschlechter von P. angustatus zeigen keine Unterschiede in der Verteilung ihrer Schlüpfzeiten.

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Experiments on adult emergence rhythms in Carabid bettles

Summary The emergence times of the following species of Carabid beetles were investigated in a long day of LD 18/6: Agonum assimile Payk., Pterostichus angustatus Dft., P. nigrita F., and P. oblongopunctatus F.The hatching of the beetles was examined by means of an automatically controlled photorecorder.In one series of experiments flash-light was used for taking photographs. In a second series photographs were taken only during the light phase by the light of a fluorescent tube of the same type as used for the illumination of the breeding chamber.Both series of experiments produced no evidence of the existence of a typical emergence rhythm in the four Carabid species. In each species the number of beetles hatched per hour is slightly greater during the phtophase than during the scotophase. This difference was statistically significant only for P. angustatus. From this it is concluded that some Carabid species have a latent capability for synchronization of emergence by a light dark change.The sexes of P. angustatus show no difference in the distribution of their emergence times.

     

UV-sensitivity and UV-mutability of infectious lambdaDNA: reactivation, protection and mutability in various assay systems

Summary The UV-sensitivity of phage and its infectious DNA have been compared in experiments involving infection of normal cells by phage and transfection of lysozyme-EDTA spheroplasts or Ca⁺⁺-treated cells by phage DNA. It is shown that UV-irradiated DNA undergoes extensive HCR. Since intact phage and free phage DNA have the same survival after UV-irradiation in Hcr^- spheroplasts and cells, resp., and since survival is also identical in Ca⁺⁺-treated Hcr⁺ cells it is concluded that DNA in solution or packaged in the phage head provides the same target for the induction of lethal UV lesions. This conclusion is supported by the observation that cysteamine provides a similar radioprotection to the intact phage and its free DNA. Spheroplasts of Hcr⁺ cells, however, have an HCR capacity reduced by about 20% when compared with normal or Ca⁺⁺-treated cells. Moreover, UV-reactivation of irradiated DNA, which is absent in spheroplasts, occurs efficiently in Ca⁺⁺-treated cells. Possible reasons for the physiological difference between spheroplasts and normal cells are discussed. c-mutations, which are readily induced by UV in phage assayed with E. coli mul ^-, could not be induced in DNA when assayed with spheroplasts or Ca⁺⁺-treated cells of this strain. No mutants were also found with DNA extracted from UV-irradiated phage. The significance of the mode of entry of UV-irradiated DNA into a cell for the production of mutations is discussed.     

Activities of enzymes of amino-acid metabolism in Pennisetum seedlings grown in the presence of 2-chloroethylphosphonic acid

The plant growth regulator 2-chloroethylphosphonic acid (CEPA) slightly inhibited the elongation of growth in Pennisetum typhoides seedlings, but greatly stimulated the activity of alanine aminotransferase (GPT), asparate aminotransferase (GOT), as well as glutamate dehydrogenase (GLDH).