Feinstruktur der Leberzellen vonOxidus gracilis (C.L. Koch, 1847) (Diplopoda,Paradoxosomatidae)

Zusammenfassung Bei den Vertretern einiger Diplopoden-Familien ist der Mitteldarm von einer zelligen Hüllschicht umgeben. Die Perikaryen stehen dicht bei dicht, basale Ausläufer durchziehen die Fasern der Muskularis und verzweigen sich sekundär beim Eintritt in die sehr dicke Basallamina des Mitteldarmepithels. Die terminalen Endigungen jeder Zelle dringen in ein extrazelluläres basales Labyrinth je einer ausdifferenzierten Mitteldarmzelle ein und verflechten so die Hüllschicht mit dem Darmepithel. Darüberhinaus scheint es Fusome zwischen den Endaufzweigungen und der Mitteldarmzelle und damit die Möglichkeit eines intrazellulären Stofftransports zwischen beiden Zellen zu geben.Die Hüllschicht ist kein Epithel, denn Zellkontakte zwischen benachbarten Zellen fehlen ebenso wie eine gemeinsame Basallamina. jede Zelle ist von ihrer eigenen, dünnen Basallamina umgeben. Sie wird außerdem bei normal ernährten Individuen durch einen großen Vorrat an Glykogen und zahlreiche Zytosomen charakterisiert. Viele Mitochondrien sind dadurch vor allem in die Zellperipherie oder in die basalen Ausläufer gedrängt. In deren Nähe findet man auch überwiegend glattes endoplasmatisches Retikulum, und auch freie Ribosomen sind nicht selten. Der Zellkern vermittelt den Eindruck hoher Stoffwechselaktivität; ein Nukleolus ist immer vorhanden. Mikrotubuli sind im Zellkortex parallel zur Oberfläche orientiert, vor allem aber in den basalen Ausläufern in Längsrichtung. Obwohl kein Fett gespeichert wird, kann man die Zellen mit dem Chloragog-Gewebe der Anneliden oder mit den Leberzellen der Vertebraten vergleichen. Sie scheinen von den Mitteldarmzellen Nährstoffe zu übernehmen, diese zu verarbeiten, die Produkte freizusetzen oder zu speichern und dabei wertlose stickstoffhaltige Moleküle in den Zytosomen abzulagern. Der gebräuchliche Terminus Leberzellen ist daher angebracht.Tiere, die 14 Tage ohne Nahrung gehalten wurden, zeigen eine erhebliche Schrumpfung der Leberzellen. Deren Plasmalemm ist nur an einigen Stellen mit der Basallamina verbunden, überall sonst ist der extrazelluläre Raum zwischen Zellmembran und Basallamina stark erweitert. Das Glykogen ist größtenteils abgebaut. Der elektronenoptische Kontrast der verschiedenen Zellelemente ist äußerst schwach. Die Mikrotubuli sind völlig verschwunden. Nur die Zytosomen heben sich weiterhin deutlich ab. Aber auch sie scheinen umgewandelt und zu wenigen Ansammlungen zusammengeflossen zu sein. Dies deutet auf Mobilisierung des gespeicherten Glykogens hin, kann aber auch beginnende Degeneration der Leberzellen signalisieren.

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Fine structure of the liver cells ofOxidus gracilis (C.L. Koch, 1847) (Diplopoda, Paradoxosomatidae)

Summary In some families of Diplopods the midgut is surrounded by an enveloping cell layer. Basal runners of their pericarya get through the longitudinal and transversal muscle fibres and ramify secundarily before entering the very thick basement membrane of the midgut epithelium. The terminal branches of each cell enter into a basal labyrinth of only one differentiated midgut cell interlacing intensively with the epithelium in this way. Moreover it seems that there are open junctions (fursomes) between terminal branches and the midgut cell and therefore an intracellular transport of materials.The enveloping layer is no epithelium. THere are no typical contacts between neighbouring cells; each enveloping cell is surrounded by its own thin basement membrane, a common basement membrane does not exist. Enveloping cells of normally nourished individuals are characterized by a large storage of glycogene in the cytoplasm. Besides this there are many distinct cytosomes which point at a significant activity in metabolism. Many mitochondria, which mostly pushed off towards the cell periphery or lie in the primarily ramifications indicate the same. Close by there is also prevailing smooth endoplasmic reticulum. Free ribosomes are not rare. The nucleus gives the impression of activity in metabolism too; a nucleolus does exist. Microtubules arranged parallely to the cell surface in the cortex, but especially in the basal ramifications in longitudinal direction can be seen. Though lipoids are not being stored, one might compare these cells with the chloragog tissue in annelids or with the liver cells in vertebrates. They seem to accept food from the midgut cells, to digest and release, respectively store it temporarily, depositing at that valueless nitrogene containing molecules into the cytosomes. The usual term liver cell therefore is wellchosen.Animals after 14 days without food signify a large shrinkage of the liver cells. Plasmalemma is fixed only at certain points to the basement membrane; the extracellular space between them is widened extremely. Glycogene mostly is removed. The electron microscopically visible contrast of the cell elements is very faint. Microtubules have disappeared. Cytosomes, however, contrast distinctly. But they, too, seem to be transformed and joined into a few accumulations. This points to mobilization of the stored glycogene, but in the same manner also to symptomes of degeneration brought into action.

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Herrn Professor Dr. Dr. h.c. W.E. Ankel zu seinem 80. Geburtstag am 7.8.1977 gewidmet     

The consumption and utilization of two different species of leaf litter by a laboratory population of Orthomorpha gracilis (Diplopoda: Polydesmoidea)

Over a period of 7 months several individuals of the millipede Orthomorpha gracilis were cultured in groups of two. Individuals were reared to maturity from eggs laid in the laboratory on 0 to 6-month-old dead, preferred leaf litter of Ficus sycamore and 0 to 6-month-old dead, less preferred leaf litter of Aesculus sp. The quantity of food eaten (dry weight) by each individual during each stadium when reared on a species of leaf litter was estimated. Notwithstanding the differences in the qualities of the two species of leaf litter, similar quantities of any species of leaf litter were necessary to carry an individual through a given stadium. Nevertheless, animals reared on leaves of Ficus sycamore developed in a shorter time and gained more weight than those reared on leaves of Aesculus sp. The differences in the rate of development were due to the relatively shorter periods spent in moulting.

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Résumé Le Myriapode Orthomorpha gracilis a été élevé en laboratoire pendant une période de 7 mois, par groupe de deux individus, de l'oeuf à l'état adulte. Ces individus préfèrent la litière de feuilles de Ficus sycamore, feuilles âgées de 0 à 6 mois, à la litière de feuilles de même âge de Aesculus sp. On a mesuré la quantité de feuilles absorbées (en poids sec) pour chaque individu, au cours de chaque stade de son développement. La quantité de feuilles consommées est la même au cours d'un stade déterminé de la croissance, et cela indépendamment des différences de qualité des deux espèces de litières. Néanmoins les animaux élevés sur feuilles de Ficus sycamore se développent en un temps plus court et leur poids croît plus vite que celui des animaux se nourrissant de feuilles d'Aesculus. La différence observée dans la vitesse du développement est due au raccourcissement de la durée des périodes de mue.

     

Spermatophorenbau und samenübertragung bei uropygen (Mastigoproctus brasilianus C. L. Koch) und amblypygen (Charinus brasilianus Weygoldt und Admetus pumilio C. L. Koch) (Chelicerata,Arachnida)

The spermatophores of Amblypygi and Uropygi are complicated structurs and vary in different species. In Mastigoproctus, the size and shape of the spermatophores prevent bastardation between M. giganteus and M. brasilianus. Taxonomic and phylogenetical implications are discussed.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Comparative midgut ultrastructure of unfed larvae and adult mites of Platytrombidium fasciatum (C.L. Koch, 1836) and Camerotrombidium pexatum (C.L. Koch, 1837) (Acariformes: Microtrombidiidae)

The midgut of unfed larvae and adult mites of Platytrombidium fasciatum (C.L. Koch, 1836) and Camerotrombidium pexatum (C.L. Koch, 1937) (Acariformes: Microtrombidiidae) was investigated by electron microscopy. The sac-like midgut occupies the entire body volume, ends blindly and is not divided into functionally differentiated diverticula or caeca. The midgut walls are composed of one type of digestive cell that greatly varies in shape and size. In larvae, the lumen of the midgut is poorly recognizable and its epithelium is loosely organized, although yolk granules are already utilized. In adults, the midgut forms compartments as a result of deep folds of the midgut walls, and the lumen is well distinguished. The epithelium is composed of flat, prismatic or club-like cells, which may contain nutritional vacuoles and residual bodies in various proportions that depend on digestive stages. In both larvae and adult mites, parts of cells may detach from the epithelium and float within the lumen. The cells contain a system of tubules and vesicles of a trans-Golgi network, whereas the apical surface forms microvilli as well as pinocytotic pits and vesicles. Lysosome-like bodies, lipid inclusions and some amount of glycogen particles are also present in the digestive cells. Spherites (concretions) are not found to be a constant component of the digestive cells and in adult mites occur for the most parts in the midgut lumen.     

Spermiogenesis and structure of spermatozoa in the oribatid mite,Hafenrefferia gilvipes (C.L. Koch) (Acari,Oribatida)

The process of spermiogenesis and the structure of spermatozoa in the mite, Hafenrefferia gilvipes (Koch) were studied ultrastructurally. Spermiogenesis was divided into six stages. The spermatids at stage 1 have the usual structure. At stage 2 the structure of the mitochondria and their distribution in the spermatid start to change, leading to the formation of specific mitochondrial derivatives which are subsequently incorporated into the nucleus of the spermatozoon. Parallel to the transformation of mitochondria occurs a reorganization of the nuclear material. The fully formed spermatozoon has a tadpole-like shape, with the cell nucleus located in the distended part of the cell, and containing mitochondrial derivatives in its karyoplasm. Acrosome, flagellum and centrioles are absent. The participation of peripherally distributed microtubules, present in spermatids at stages 4 to 6, in the shaping of the spermatozoon has been suggested.     

鹅观草属的地理分布

鹅观草属是禾本科小麦族中的最大的属,现知全世界有4组,20系,126种,分布于北半球的温带和寒带,中国有4组,18系,79种,主要分布于西北,西南,华北和东北,是鹅观草属植物种类最为集中的区域,尤其高原东北部的唐古特地区又是我国鹅观草属分布相对密集之地,有3组,12系,30种,而且其间不同等级,不同演化水平的类群均有分布,该地可能就是该属的现代分布中心,同时,唐古特地区多汇聚有鹅观草属不同等级的原始类群和与原始类群有很缘的短柄草属植物,其中最原始的大柄鹅观草特产于该区,而该区缺乏的是高级的大颖组类群,故推测唐古特地区可能又是该属的起源地,起源时间大约在青藏高原明显增高,气候转凉的晚第三纪初的中新世,鹅观草属起源后,在中国境内地质活动比较剧烈的地区得到了进一步的发展和分化,但只有少数适应性较强的类群大概以3条路径扩展到国外,并向东到在北美的巴芬岛,向西延伸到大西洋滨岸,向北进入寒冻的北极地区。     

Neural factors in the regulation of oxygen consumption rhythm in the tissues of the scorpion, Heterometrus fulvipes (C. Koch)

Circadian variation in the effect of cephalothoracic nerve mass (CTNM) extract and blood of the oxygen consumption of the isolated hepatopancreas of the scorpion, Heterometrus fulvipes, was studied. Both CTNM extract and blood from 2000 animal cause maximum increase in oxygen consumption. Another maximum increase was also noted at 0800. It is inferred that a chemical factor from the CTNM is responsible for the observed changes in oxygen consumption of hepatopancreas.     

Different ontogenetic processes promote dicliny in Ficus L. (Moraceae)

The absence of reproductive organs in flowers may ontogenetically arise from inception or by abortion during development. Ficus L., a species-rich genus of angiosperms, is an interesting model for floral developmental studies because of the diversity of sexual systems it contains. This study compares the floral morphology of Ficus citrifolia (monoecious), Ficus religiosa (monoecious), Ficus racemosa (secondarily monoecious), and Ficus hispida (gynodioecious) across development to establish the ontogenetic pathways that result in diclinous flowers. Figs were collected at various developmental stages and were prepared for surface (scanning electron microscopy) and histological (light microscopy) analyses. Dicliny in Ficus is defined by stamen absence from inception in pistillate flowers and either pistil absence from inception (F. citrifolia, F. racemosa and F. religiosa) or by abortion (F. hispida) in staminate flowers. The perianth is formed by a single whorl of sepals, as found in other families related to Moraceae. The gynoecium is tubular during development, a condition that may be related with pseudomonomery. The staminate and neutral flowers in F. hispida develop by similar mechanisms. The diversity in the sexual systems in Ficus results from combinations of different floral morphs (dicliny), which originate from both previously established ontogenetic mechanisms (loss of reproductive organ function by abortion or from inception). These mechanisms act independently of phylogenetic proximity or mechanisms of sex system evolution in Ficus. Other aspects of floral development observed in Ficus are discussed in relation to their systematic position and reproductive biology.