Verteilungsmuster und Ultrastruktur des Glykogens in der Oocyte vonMusca domestica

Summary Fully grown oocytes ofMusca domestica contain large amounts of glycogen distributed in a characteristic pattern. Three cytoplasmic layers can be distinguished: 1. The periplasm which is free of carbohydrates and merely contains some lipid and protein yolk. 2. A zone of large glycogen clods. 3. Adjacent to this the central ooplasm where numerous lipid droplets and protein yolk spheres are found beside medium size glycogen clods. The glycogen areas are not surrounded by membranes, in contrast to the other yolk inclusions. Some possible interpretations of this ooplasmic pattern, which is already established during oogenesis, are discussed.     

Induktion von Tumoren und Produktion des Phagen PS8 durch Agrobacterium

Summary Isolated, intact spinach chloroplasts incubated in light in the presence of HCO ₃ ^- and NO ₂ ^- have the greater proportion of their NADP present in the reduced form. The steady state concentration of NADPH in light in these chloroplasts is significantly higher in the presence of NO₂ than in its absence. These results invalidate earlier conclusions (Grant and Canvin, 1970) that NO ₂ ^- inhibits photosynthesis by preventing NADP reduction.This work was supported by the National Research Council of Canada.     

Hemmung der Cytokinese und Bildung von Riesenzellen beiPoterioochromonas malhamensis durch organische Bleiverbindungen und andere Agenzien

Summary Organic lead compounds inhibit cytokinesis of the chrysophycean flagellatePoterioochromonas malhamensis leading to giant, multinucleate cells. This action on cytokinesis is compared with the long-time effects of various compounds with better known subcellular activities.Calcium (10 mM), and cytochalasin B (up to 100 g/ml) do not visibly influence cytokinesis. Caffeine (1 mM) totally inhibits multiplication of the algae whereas calcium has only a slight and cytochalasin has no effect on this parameter.The other reference-compounds (colchicine, sodium cacodylate, deuterium oxide, local anesthetics, and sodium dodecylsulfate) all inhibit cell multiplication, simultaneously leading to giant multinucleate cells, obviously by inhibition of cytokinesis.The most potent inhibitor of cytokinesis is triethyl lead which was shown to be 250× more effective than colchicine in respect to the molar concentrations.The comparison of the effects of tetraethyl lead and triethyl lead with the reference agents leads to the conclusion that organic lead compounds might inhibit cytokinesis ofPoterioochromonas malhamensis by disintegrating peripheral microtubules and/or by interfering with structures and functions of membranes.

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Verwendete Abkürzungen im Text CB Cytochalasin B - KE Karminessigsäure - KV kontraktile Vakuole - LV Leukosinvakuole - MT Mikrotubuli - SDS Na-Dodecyl-sulfat - TEL Tetraäthylblei - TriEL Triäthylblei     

Zur Frage der Induktion von Linse durch Pigmentepithel

Ohne Zusammenfassung     

über Induktion von Embryonalanlagen durch Implantation artfremder Organisatoren

Ohne Zusammenfassung     

Hemmung der Wurzelneubildung durch saure und neutrale Kernproteine

Summary An acidic (Fs) and a nearly neutral (Fn) protein fraction were extracted from the chromatin of calf thymus and pea seedlings. Both fractions are able to combine with protein-free DNA to form a complex, which, however, has a lower thermal stability than a DNA-histone complex. Fs and Fn inhibit root initiation in a similar manner as histone, actinomycin-D, streptomycin and 5-bromouracil do when these substances are applied to regenerating pea epicotyls during different times after culture initiation.Oxidized and thermally denaturated Fs and Fn inhibit root initiation less than untreated proteins do. Furthermore the treated proteins act in a more specific way on special steps of development such as root differentiation or root growth. In a very similar manner inhibition of root regeneration is also restricted to special developmental steps by treatment of Fs or Fn with small amounts (1 g/ml) of IAA, GS or KI at pH8. With increasing acidity of the chromatin proteins treatment with IAA diminishes the inhibition of root growth, whereas root differentiation is preserved.The results support the suggestion that acidic and neutral proteins of the chromatin may act as regulators of DNA-activity as histone does. During IAA-induced root formation Fs acts as an antagonist to histone, because these two protein fractions are specialized in their action by IAA treatment in a contrary manner.     

Versuche zur Induktion von Pollensterilität bei den Selbstbefruchtern Sommergerste,Sommerweizen und Hafer

Zusammenfassung Von den 1964 bei Sommergerste, Sommerweizen und Hafer auf ihre gametozide Wirkung geprüften 20 Substanzen wurden 1965 nochmals je 5 bei Weizen und Gerste bzw. 4 bei Hafer untersucht. Nur bei Sommerweizen schien durch die Anwendung von Maleinsäurehydrazid und Omnidel spezial eine chemische Kastration möglich zu sein. Die Ergebnisse von 1966 zeigten auch nach Kombination der Mittel keinen ausreichend hohen Effekt, der für einen Einsatz der Mittel in der Züchtung sprechen würde.Gibberellin ergab, ebenso wie die meisten geprüften Chemikalien, keine eindeutige Reaktion. Die erhaltenen Ergebnisse deuten auf eine witterungsabhängige Wirkung der verwendeten wirksamen Substanzen hin.

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Experiments on the induction of pollen sterility in self-fertilizing spring barley, spring wheat, and oats

Summary In 1964 we tested 20 substances for their gametocidal action on spring barley, spring wheat, and oats. One year later we tested five of these again on wheat and barley, and four of them on oats. Only in wheat did it seem possible to achieve chemical castration by maleic hydrazide and Omnidel. The results of 1966 had no appreciable effect even when the two herbicides were used in combination. Thus it is not possible to use these substances as gametocides in the breeding of cereals.Gibberellin, like most other chemicals, produced no clear reaction. Our results lead to the conclusion that the action of efficient substances is influenced by weather conditions.

     

Rectale Chloridepithelien und osmoregulatorische Salzaufnahme durch den Enddarm von Zygopteren und Anisopteren Libellenlarven

The larvae of Coenagrion puella possess 3, and the larvae of Aeshna cyanea up to 486 rectal chloride epithelia which in both species are organized as transporting epithelia. Combined applications of the histochemical chloride precipitation technique, energy-dispersive micro-analysis of X-rays, autoradiography, and scintillation counting on A. cyanea revealed that the chloride epithelia adsorb chloride from the external solution. By use of radioactive sodium and chloride in hypotonic concentrations applied on normal and anus-sealed larvae it was demonstrated that the rectum of both species is the main pathway for salt uptake into the haemolymph. The stepwise increase in external osmolarity by the addition of mannitol results in a concomitant reduction of chloride uptake into the haemolymph. These results suggest that the rectal chloride epithelia are involved in hyperosmotic regulation by the absorption of salt from the external medium.     

Hemmung von Pflanzenviren durch Membranlipidanaloga unter besonderer Berücksichtigung von Alkanmonosulfonaten

Inhibition of plant viruses by membrane lipid analogs under special regard of alkane monosulfonates Under investigation was the inhibition of plant viruses by compounds, which could be comprehended as membrane lipid analogs because of some structural similarities to these lipids. Among these analogs, alkane monosulfonates (AMS, preparation “Emulgator E 30”) exhibit distinctly marked antiphytoviral activities, which are reported in detail. The mentioned AMS reduced the concentrations of PVX (potato virus X) as well as of TMV (tobacco mosaic virus) markedly in inoculated leaves of Nicotiana tabacum L. ‘Samsun’ and remarkably in secondarily infected ones. The formation of local lesions on leaves of hypersensitive hosts is influenced strongly by AMS. Likewise, the activity of the free virion is reduced in vitro. The mentioned effectsproved dependent on the length of the alkane chains and the concentration of AMS. Innertherapeutical effects of AMS have been pointed out. Several substances proved excellent coergists of AMS and vice versa, above all DHT (2,4-dioxohexahydro-1,3,5-triazine), several guanidines, a thiourea compound, a thiadiazole compound and ribavirin. In part full synergistic effects were obtained. AMS as well as combinations of AMS with some of the mentioned coergists also influence potato viroses. Using so-called identical potato eye cuttings, it was demonstrated that the mentioned treatments resulted in a significant and in part considerable reduction of the number of potato eye cutting plants with virus symptoms and in a partially high increase in the weight of tubers formed by the eye cutting plants. Likewise, the number of plants with virus symptoms was reduced and the tuber mass was increased by newly developed granulated AMS. A combined treatment with granulated AMS and granulated DHT resulted in a strong reduction of the number of potato eye cutting plants with virus symptoms, but the tuber mass was not augmented.     

Hemmung der Blütenbildung von Lemna gibba durch Ammonium

Summary Ammonium ions completely inhibit the flowering of Lemna gibba G1 and G3 without a simultaneous effect on the growth and multiplication of fronds. A concentration of 10^-4 M NH ₄ ⁺ is effective in strain G3.The NH ₄ ⁺ -inhibition of flowering is reversed by ATP and, more effectively, by ADP.With reference to recent literature the opinion is confirmed that ammonium ions cause a decrease of the ATP available in relation to the level of NAD(P)H and as a consequence flowering is inhibited. Possible primary actions of ammonium ions are the uncoupling of photophosphorylation, the repression of nitrate- and nitrite-reductase and the increase of NH ₄ ⁺ -detoxication processes.