Gruppen-Gründung und Reproduktion bei Nacktmullen (Heterocephalus glaber) im Zoo Dresden

When establishing a new breeding group of Naked mole-rats three significant hurdles are to overcome: 1. Determination of sex. 2. Get over the group specific smell (between individuals of different groups). 3. Get over the reproductive blockade. This report describes experiences achieving these goals as well as establishes requirements for a successful breeding. The sex determination of nonreproductive Naked mole rats is tainted with great uncertainty, because the anogenital region of both sexes appears quite similar. For a lack of births and a failure of rearing offspring the following reasons seem to be responsible: 1. Incorrect sex determination at the time of group founding. 2. The reproductive blockade could not be overcome because of disadvantageous hierarchical relations within the group. 3. Pregnancy is interrupted due to disturbances from outside the enclosure or social stress within the group. 4. Due to these disturbances the alpha-female is not often enough willing to suckle her youngsters.     

Die Schalenbildung bei Difflugia oviformis (Rhizopoda,Testacea)

Zusammenfassung Die Schale von Difflugia oviformis ist aus Idiosomen zusammengefügt, d.h. kieseligen Elementen, die in verschiedener Anzahl, Gestalt und Größe in der Zelle vorgefertigt werden. Xenosomen, etwa Quarzkörnchen oder Glassplitter, werden nur gelegentlich in die Idiosomenschicht eingebaut. Die Zellteilung beginnt mit der Morphogenese einer neuen Schale für einen der beiden Abkömmlinge. Eine cytoplasmatische Knospe quillt aus der Öffnung des alten Gehäuses. Die Idiosomen für die neue Schalenwand tauchen nach und nach aus dieser Knospe auf. Die Oberfläche der jungen Anlage erscheint zunächst wellig — die Bauelemente sind in mehreren diskontinuierlichen Lagen gestaffelt, wird jedoch gegen Ende der Morphogenese glatt, wenn die Idiosomen auf eine einzige, kontinuierliche Lage verteilt und in einem Zufalls-Mosaik miteinander verkittet sind.

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Test formation in Difflugia oviformis (rhizopoda, testacea)

Summary The test of Difflugia oviformis is composed of idiosomes, i.e. silicious elements, prefabricated within the cell in various shapes and sizes. Xenosomes, such as grains of quartz, are only occasionally incorporated into the mono-layer of idiosomes. Cell division begins with the morphogenesis of a new test for one of the two offsprings. A cytoplasmic bud protrudes from the aperture of the shell. The elements for the construction of the thecal wall emerge successively from this anlage. The surface of the early anlage first appears to be wrinkled or undulated—the elements being distributed in several discontinuous layers—but becomes smooth towards the end of morphogenesis, as soon as the idiosomes are arranged and glued together in a random mosaic pattern to form a single, continuous stratum.

Mit Unterstützung durch die Deutsche Forschungsgemeinschaft; gefördert durch den Sonderforschungsbereich 53 Paläontologie unter besonderer Berücksichtigung der Palökologie, Tübingen. Technische Assistenz: Gudrun Monnier, Rosemarie Freund, Barbara Grunewald.     

Bestand und Reproduktion des H?ckerschwans in Bayern

Ohne Zusammenfassung     

DNA-Replikation und Chromosomenstruktur von Mesostoma (Turbellaria)

During meiosis in M. ehrenbergi (2n=10) and M. lingua (2n=8) male certain chromosomes never pair completely. In these bivalents only terminal pairing appears, crossing over could not be proved by ³H-thymidine autoradiography. DNA amounts of the M. ehrenbergi and M. lingua genomes are in a proportion of 10∶1. The mitotic S-phase of spermatogonia in M. ehrenbergi is twice as long as in M. lingua. In metaphase of spermatogonia a differentiated DNA replication pattern can be identified in M. ehrenbergi as late-pulse-replicating segments. After incorporation of ³H-thymidine X₂-metaphase chromosomes can be found, which show single chromatid labeling, terminal and intercalary isolabeling as well as kinds of chromosome labeling, which can only result from sister strand exchange. After treating the chromosomes with low temperature, colchicine or by hydrolysis (60° C) substructures of the chromatin become visible in both spezies which however are evaluated as artefacts. — Formation of the different isolabeling types is discussed on the basis of a two-strand model of the chromosome fibril. A hypothesis is formulated that the surplusage of DNA in M. ehrenbergi is distributed over all the length of the chromatids as small parts of heterochromatin. This hypothesis is supported by investigations of the DNA replication and the contractility of the chromosomes. Furthermore, a pattern of small DNA particles can be demonstrated after partial destruction of the DNA in metaphase chromosomes of M. ehrenbergi, which could represent this intercalary heterochromatin.     

Electron-Microscopic Observations of Gromia oviformis (Sarcodina).

SYNOPSIS. Gromia oviformis from New Zealand has been examined in thin sections after fixing in osmium tetroxide and embedding in methacrylate. The structure of the protein and acid mucopolysaccharide shell and the canals which pass radially through it are described. Multiple honeycomb membranes located between the shell and the cytoplasm, as well as mitochondria and "Golgi bodies," none of which has hitherto been seen in light microscope studies, are discussed and illustrated. The previously known stercomata and xanthosomes are considered. Though still regarded as enigmatic cytoplasmic inclusions, observations suggest that they are waste products retained within the animal throughout life.     

Lebensweise und umweltbeziehungen von trialeurodes vaporariorum (Westwood) (homoptera-aleurodina)

Ohne ZusammenfassungMit Unterst ützung durch die Notgemeinschaft der deutschen Wissenschaft.     

The finding of Exorchis oviformis (Trematoda: Cryptogonimidae) in the southern Maritime Territory

Some new data on the expansion, host-animals, biology and morphology of different developmental stages of the trematode Exorchis oviformis in the southern Prymorye are given. It was revealed, that the first intermediate host of that species is Stenothyra (S.) recondita. Different species of freshwater fishes play a role of a second intermediate host. The definitive host of E. oviformis is a bullhead (Parasilurus asotus).     

Kultur und Entwicklung von Chlorocloster engadinensis Vischer (Xanthophyceae)

Zusammenfassung Die autotrophe, mixotrophe und heterotrophe Kultur der einzelligen Xanthophycee Chlorocloster engadinensis Vischer wird beschrieben. Diese Alge kann unter allen drei Bedingungen mit vergleichbaren Wachstumsraten kultiviert werden. Sie stellt neben den bekannten Chlorophyceen Chlorella, Scenedesmus und Ankistrodesmus ein weiteres günstiges Objekt für die Algenphysiologic aus einer mit diesen Algen nicht verwandten Klasse dar.Es wurde ein fördernder Effekt von Schwachlicht auf die Verwertung von Kohlenhydraten und eine Hemmung der Mitosen bei Kultur in glucose-oder fructosehaltiger Nährlösung im Licht festgestellt. Letzteres führt zur Bildung von Riesenzellen.Die normale Entwicklung von Chlorocloster engadinensis und die Bildung von Akineten und Cysten werden beschrieben.Die Beziehungen von Chlorocloster engadinensis zu den einzelligen Xanthophyceen und die Möglichkeit einer Revision dieser Algen aufgrund physiologischer Merkmale werden diskutiert.     

Vorkommen und biologische Bedeutung von Benzopyranen (Chromenen) und Benzofuranen in denAsteraceae

Benzopyrans (chromenes) and benzofurans are characteristic natural products of theAsteraceae and are found together with their biogenetic precursors primarily in the tribesAnthemideae, Astereae, Eupatorieae, Heliantheae, Inuleae, andSenecioneae. The accumulation of benzopyrans and benzofurans supports an arrangement of the tribes of theAsteraceae into two groups as suggested recently based on morphological characters. The methods for analysing this class of natural products are demonstrated with the American genusEncelia. Experiments on the localization of benzopyrans and benzofurans inEncelia species indicate that these compounds are stored in resin ducts. Several benzopyrans and benzofurans are biologically active and are repellent as well as toxic towards herbivorous insects. Experiments on structure — activity relationships indicate the biological activities as being influenced by the heterocycle (pyranvs. furan) as well as by the substituents of the aromatic ring. In addition, several tested compounds showed phototoxic activities.

Vorgetragen auf der Tagung der Deutschen Botanischen Gesellschaft, Wien, September 1984.     

Chloroplastenausbildung und Morphogenese der Gametophyten von Dryopteris filix-mas (L.) Schott nach Applikation von Chloramphenicol und Actidion (Cycloheximid)

Summary Morphogenesis and differentiation of the young gametophytes (=sporelings) of Dryopteris filix-mas are controlled by light. Blue light leads to the formation of normal two-dimensional prothallia; under red light, however, the gametophytes grow as cellular filaments. Morphogenesis in blue light is connected with an increase in protein synthesis; in red light the protein content of the sporelings is markedly lower. The size of the chloroplasts is correlated with the protein content of the sporelings.In the present paper the diverse effect of chloramphenicol (CAP) and actidione (cycloheximide, ACT) was studied in connection with the formation of chloroplasts. ACT blocks the growth of the gametophytes, while the chloroplasts remain functional. On the other hand, CAP does not influence morphogenesis of the gametophytes. In particular the activity of the dividing apical cells remains untouched. Even when the light quality is changed during the development the corresponding specific effect of the light quality on morphogenesis is normal. The chloroplasts, however, become smaller, probably by inhibition of synthesis of structural proteins. But their synthetic activity is not completely suppressed. The specific blue or red light dependent morphogenesis is not changed, when protein synthesis in the chloroplasts is inhibited.     

Zur entwicklungsgeschichte und entwicklungsmechanik von Craspedacusta (Hydrozoa,limnotrachylina)

Ohne ZusammenfassungHerrn Prof. Dr. K. v. Frisch zum 70. Geburtstag gewidmet.     

Haltung und Zucht von Schläfenfleckspechten (Melanerpes pucherani)

Many unique natural habitats have already been disturbed by mankind. At the same time a lot of animal- and plant species have reach the point of no return and so their extinction. The human private efforts for conservation are becoming more and more important.In these efforts zoological gardens as international conservation organisations and private initiatives should go hand in hand.About the breeding of woodpeckers for instance, literature does not show that much. In this case it would be of highly importance in publishing any experience in this matter.The breeding of the Black-cheeked woodpecker is more or less uncomplicated. In spite of his tropical origin, this species is not that sensitive against coldness as other South-American birds. Soft food, fruit and mealworms will be a decent basic food. Even during the breeding-season this kind of food will be totally ok. In the birds enclosure, only a single bird or a couple should be put in. Probably because of their territorial claim, they will become aggressive otherwise. Also very important for this species will be to keep them out of sight from each other. Even housing at hearing distance could be problematic for the brood. To keep this species with other bird species in a community will be possible. In literature until four eggs per brood could be possible. However, even in separated enclosures as mentioned above, these results have never been reached until now.     

Kombinierte Wirkung von Kaliumpermanganat und p-Benzochinon auf die Conidien von Fusarium decemcellulare (Brick)

Ohne ZusammenfassungTeilergebnisse der Dissertation Über das Wirken einiger Schwermetallsalze und Kaliumpermanganat auf die Hemmung der Pilzsporenkeimung durch fungicide Chinone der Mathematisch-Naturwissenschaftlichen Fakultät der Friedrich Schiller-Universität Jena, 1962.