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Zusammenfassung Der Einfluß verschiedener Bodenmikrofloren und Bakterienreinkulturen wurde in Wasserkultur auf das Wachstum von Rotklee untersucht.Sämtliche geprüften Bodenmikrofloren bewirkten eine Erhöhung des Sproß/Wurzel-Verhältnisses der Pflanzen, allerdings in unterschiedlicher Weise. Unter den Mikrofloren befanden sich solche, die auf das Wurzelwachstum eine gleich starke Hemmung ausübten, das Sproßwachstum hingegen unterschiedlich beeinflußten. Bei geringer oder fehlender Hemmung des Wurzelwachstums war das Sproßwachstum unter nichtsterilen Versuchsbedingungen größer als bei steril kultivierten Pflanzen. Damit konnte gezeigt werden, daß außer den allgemein bekannten Waschstumsfaktoren die Bodenmikroflora als weiterer Wachstumsfaktor eine nicht unwesentliche Rolle zu spielen vermag.Mit Reinkulturen von Bacillus mycoides, Mycobacterium phlei, Pseudomonas fluorescens, Rhizobium spp. und drei weiteren nicht identifizierten Bakterien wurde keine statistisch gesicherte Verschiebung des Sproß/Wurzel-Verhältnisses der Pflanzen beobachtet.Während die beiden erstgenannten Bakterienreinkulturen sich nur schwach in der Rhizosphäre vermehrten, fanden die Rhizobium spp. und die drei nicht identifizierten Bakterien unter gleichen Wachstumsverhältnissen sehr günstige Lebensbedingungen. Pseudomonas fluorescens wies ähnlich wie die Bakterienpopulation der verschiedenen Bodenmikrofloren mittlere Keimzahlen auf.Aus einem Versuch über den Belichtungseffekt auf das Wurzelwachstum wird auf die Beteiligung eines lichtempfindlichen von gewissen Rhizosphärenmikroorganismen gebildeten Wuchsstoffes geschlossen.
Summary The effect of different soil microflores and bacteria pure cultures on the growth of red clover (Trifolium pratense) has been investigated in aqueous culture.All examined microflores increased the shoot/root ratio of the plants, however in a different way. Among the microflores were those which effected an equally strong inhibition on the root growth while influencing the shoot growth differently. If no or only a slight inhibition of the root growth occured the shoot growth was more extended under non-sterile experimental conditions than under sterile ones. Thus it could be demonstrated that beside the generally known growth factors the soil microflora as a further growth factor is able to play a not unimportant role.With pure cultures of Bacillus mycoides, Mycobacterium phlei, Pseudomonas fluorescens, Rhizobium spp. and three other bacteria not identified no significant variation of the shoot/root ratio of the plants could be observed.While pure cultures of the two forementioned bacteria could only multiply themselves weakly in the rhizosphere the Rhizobia species and the three not-identified bacteria found very favourable life conditions under equal growth situations. Pseudomonas fluorescens showed medium germ numbers similar to the bacteria population of the different soil microflores.As concluded from an experiment concerning the effect of light on the root growth, the participation of light sensitive growth promoting substance formed by certain rhizosphere microorganisms is supposed.
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Zusammenfassung Der Nukleinsäurestoffwechsel von Ehrlich-Ascites-Tumorzellen wurdein vitro nach Bestrahlung untersucht. Dabei zeigte sich — wie auch bei Untersuchungen anderer Autoren — daß die Gesamt-RNS-Synthese durch Röntgenstrahlen kaum beeinflußt wird. In weiteren Experimenten wurde die Kern-RNS nach der Methode von Georgiev u. Mantieva extrahiert, wobei zwei Fraktionen unterschiedlicher Basenzusammensetzung gewonnen werden konnten. Vorherige Bestrahlung der Zellen bewirkte in einem Dosisbereich von 1000 bis 1500 R eine Hemmung des H3-Uridin-Einbaues in die 65°C-Fraktion, während die 50°C-Fraktion vergleichsweise nur geringe Veränderungen aufwies. Untersuchungen zur Beeinflussung bereits synthetisierter RNS durch die Bestrahlung (Chase-Experimente) ergaben keinen beschleunigten Abbau bei den von uns benutzten Dosen und Methoden.
Summary The metabolism of RNA in irradiated Ehrlich ascites tumor cells was studiedin vitro. It was found — as have earlier investigators too — that the total RNA synthesis in mammalian cells is hardly affected by irradiation. In further experiments cell nuclei were prepared and two RNA fractions with different base composition were isolated according to the method of Georgiev and Mantieva (thermic fractionation). Thereby it was observed that the H3-uridine incorporation into the 65°C fraction decreased at the dose range of 1000 to 1500 R, whereas the 50°C fraction showed no marked changes in RNA synthesis. Experiments on the effect of irradiation on newly synthesized RNA (chase-experiments) produced no observable degradation of RNA under our experimental conditions.


Herrn Prof. Dr. J. Kühnau zum 70. Geburtstag gewidmet.

Diese Arbeit wurde mit Unterstiitzung der Deutsehen Forsehungsgemeinsehaft durehgeffihrt.Frau I. Schwenke danken wir ffir gewissenhafte technische Assistenz.  相似文献   

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Zusammenfassung Menschliche Lymphocyten, die am 6., 9. und 12. Tag nach Pockenschutzimpfung kultiviert wurden, zeigten keine sicher verwertbaren Chromosomenanomalien. Nach Infektion menschlicher Lymphocytenkulturen hemmt Vaccinevirus die Mitosen und zerst?rt die Zellen in toto parallel zur Dauer der Einwirkung. Numerische und strukturelle Ver?nderungen an den Chromosomen wurden nicht beobachtet.
The influence od vaccinia viruses on human chromosomes in vitro and in vitro
Summary Contradictory views are expressed in the literature on the question as to whether viruses induce anomalies in chromosomes. Vaccinia viruses in particular are generally stated to cause chromatid and chromosome breakage in L-cells (human embryonal lung tissue). The subject of the present paper is an experimental investigation of the effect of vaccinia viruses on the chromosomes of human blood lymphocytes. In the in vivo portion of this investigation the chromosomes were examined during and after viremia subsequent to vaccination. Only two of the eight vaccinated children examined showed a larger number of chromosome breaks during viremia than unvaccinated controls. This might possibly be due to different degrees of viremia, although local and general reactions were the same. Other causes might also be sought in vivo or in vitro, such as preparation of the chromosomes, or an unnoted mycoplasma infection of the lymphocyte cultures. In the in vitro portion of this investigation, cultures of human lymphocytes were infected with vaccinia viruses at different stages of incubation. In culture the virus concentrations exhibited a rapid initial decrease, which gradually tapered off during the period of observation. No increases in virus concentration were noted. The longer the period of infection with caccinia virus, the less growth shown by the lymphocytes, and the more mitotic cells with in toto destruction of the chromosome. Anomalies in individual chromosomes were not observed any more frequently than in controls.


(Direktor: Prof. Prof. Dr. ?. Kerpel-Fronius)

(Direktor: OMR Prof. Dr. med. habil. W. Plenert)

(Direktor: Prof. Dr. G. Veres)  相似文献   

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Summary Oral application of farnesyl methyl ether (FME), which allows for a continuous supply, inhibited the pupal differentiations of the integument. Animals fed during the course of the last larval instar reached the stage of grown-up feeding larvae, but did not enter the pharate pupal phase. By this way pupation could practically be delayed for any length of time. When the FME was administered from the first day of this instar a supernumerary larval molt occurred in some animals. A further molt, however, did not take place. An earlier treatment increased the number of superlarvae. Beginning the exposure to FME at the end of the last larval instar, some larval-pupal intermediates could be obtained with predominantly larval characteristics.When the continuous application was discontinued and the animals were transferred to FME-free food, a normal pupation took place.In the testes the metamorphosis changes of fusion and torsion were similarly inhibited by the juvenile hormone analogue.Furthermore, FME influenced testis growth. A dilution series was tested on two age groups (1- or 7-day-old last instar larvae). On transforming the data into the logarithms, two negative linear dose-response relationships were obtained. The regression analysis showed that both sets of data fitted simple straight-line models. The regression curves could be regarded as parallel whereby the older animals had higher testis size values at a given dose. However, compared with the size at the beginning of the FME-application, in the older animals a real decrease in volume took place.When the animals were transferred to untreated food, their testes became normal in size, fused and twisted.The dose-response relationship could be verified in vitro. Here too, a negative linear regresion of the log (testis size) on the log (FME-dose) was found. The regression coefficient did not differ significantly from that calculated from the in vivo data. Hence, FME acts directly on the testis sheath and does not control the organ size by alterations of the hemolymph.Testes will fuse autonomously if they have passed the critical period of this process. Culturing organs after this period on a FME-containing medium, they fused after one day despite the presence of the juvenile hormone analogue. However, with further incubation these fused partners separated. Testes which were already fused at the beginning of the incubation remained together. This indicates that there is a period of modifiable surface properties of the testes during which a fusion can be reversed by FME.The process of torsion does not show such a reversibility.

Die Arbeit wurde unterstützt durch die Deutsche Forschungsgemeinschaft.

Herrn Dr. F. Jochum möchte ich für seine Hilfe bei der statistischen Auswertung danken.  相似文献   

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Longevity and reproduction of adult Oncopeltus fasciatus under conditions of food deficiency or when feeding on solutions of carbohydrates are investigated. In addition to concentrations of the solutions of glucose and sucrose, age and sex are the important factors. The phagostimulants—typical glycosides of the Asclepiadaceae—increase the rate of ingestion of the sugar solutions. Activity of the α-glucosidases and carboxylesterhydrolases of the salivary glands and the midgut depends considerably on the uptake of food.  相似文献   

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Ohne ZusammenfassungDie vollständige Fassung des Vortrages erscheint im Kongreßband-Sonderheft der Strahlentherapie, Verlag Urban & Schwarzenberg, München-Berlin.  相似文献   

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The effect of anaerobiosis of wheat seedling roots during 6 consecutive days on contents of ethanol, lactate and glucose in roots and shoots and on the exudation of ethanol from roots to the medium was examined. Activities of alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH) were determined. After 36 h of anaerobiosis the concentration of ethanol in roots increased temporarily about 6 times and after 6 days it decreased to the level of control plants. The exudation of ethanol from roots to the medium showed similar pattern. The content of lactate was unaffected by anaerobiosis. In contrast, the content of glucose in roots of seedlings increased already after 1 day of anaerobiosis about 2 times and this higher level of glucose was noticed during consecutive 5 days. Anaerobiosis of roots caused an increase in the activity of ADH in both roots and shoots but the increase was not related to the content of ethanol in tissues, or exudated to the medium. The activity of LDH was unaffected by this factor. The results are discussed in relation to the limitation of energy supply of plants grown under root anaerobiosis.  相似文献   

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Dieter Klämbt 《Planta》1974,118(1):7-16
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Im Jahre 1974 wurden 9Phragmites-Bestände nach der Erntemethode in 7-oder 14tägigem Abstand untersucht. Festgestellt wurden sowohl Dichte, Frisch- und Trockengewicht pro m2 als auch Höhe und Zustand jedes einzelnen luftsprosses. Das mittlere Sprossfrischgewicht und hauptsächlich eine Zählung der Sprosse nach 10-cm-Grössenklassen dienten dazu, die jährliche Entwicklung zu veranschaulichen. Von je 2 Beständen oberhalb des Mittelwasserbereichs und im Mittelwasserbereich wurden nicht geschnittene Flächen mit Flächen, in denen die Überständer entfernt worden waren, hinsichtlich des Einflusses der Spätfröste und der Wellenerosion verglichen: Während die Röhrichte oberhalb des Mittelwasserbereichs nach dem Schnitt durch das Anwachsen der Dichte die Biomasseproduktion steigern, erreichen die geschnittenen, seewärts gelegenen Röhrichte nur einen Teil ihrer normalen Produktion. Schliesslich wurden Hinweise zur Pflege der Röhrichte abgeleitet.  相似文献   

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Ohne ZusammenfassungHerrn Prof. Dr. Dr. h. c. Dr. h. c. Dr. h. c. Boris Rajewsky zum 70. Geburtstag gewidmet.  相似文献   

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Zusammenfassung Durch Anreicherung in BUdR- und FUdR-haltigem Medium wurde in die DNS des Serratiaphagen Bromuracil (BU) eingebaut. Im CsCl-Gradienten zeigte die Dichte der BU--Partikel einen Ersatz des Thymins durch BU von 25 bis 30% an. Die Häufigkeit zweier Plaquetypmutanten (c und b) war in der BU--Population signifikant (durchschnittlich 1,4 bzw. 2,4), die des dritten Typs (e) nur insignifikant über die in BU-freien Phagen erhöht. Im Vergleich zu letzterem betrug die absolute Häufigkeit der zusätzlichen c- und b-Mutanten in BU- 2,2 × 10–4 bzw. 1,1 × 10–4.Die UV-Inaktivierung von BU- war etwa um den Faktor 1,40 höher als die des normalen . Die Inaktivierung durch Röntgenstrahlen war dagegen nur um das 1,14fache erhöht. Die Häufigkeit der durch Röntgenstrahlen induzierten Plaquemutationen wurde durch den BU-Einbau nicht merklich beeinflußt. Dagegen war die UV-Induktion der Mutationen sehr viel mehr verstärkt als die UV-Inaktivierung. Die Sensibilisierungsfaktoren der drei Mutantentypen waren verschieden und am höchsten bei niederen UV-Dosen (3,4, 5,0 und 22 für c, b bzw. e). Das bedeutet eine Annäherung der Dosiskurven an linearen Verlauf. Die zur Auslösung von Mutationen erforderliche Trefferzahl wird somit durch BU-Einbau vermindert. Für -normal entsprachen die Kurven der UV-Mutationsinduktion dem 2-Treffertyp. Es wird geschlossen, daß die Hemmung der Dunkelreaktivierung (HCR) der Letalläsionen und Prämutationen in BU-DNA nicht die einzige Ursache für die Unterschiede in den UV-Sensibilitäten ist, sondern daß die Bildung anderer UV-Produkte als in der normalen DNA ebenfalls eine Rolle spielt.
Summary Bromouracil (BU) was incorporated into the DNA of theSerratiaphage by means of culture in a medium with BUdR and FUdR. The density of BU-x particles in the CsCl-gradient indicated a replacement of about 24 to 32 % of the thymine by BU. The frequency of two types of plaquemutants (c and b) in the BU--population was increased significantly above the frequencies in BU-free phage by average factors of 1.4 and 2.4, resp. A third mutant type (e) was increased less. The absolut frequencies of additional c- and b-mutants in BU- compared with normal were about 2.10–4 and 1.10–4, resp.The UV-inactivation of BU- was higher by a factor of about 1.40 than that of normal , the inactivation by X-rays was only 1.14 times higher. The X-ray induced plaquemutation frequencies were not remarkably influenced by incorporated BU, but UV-mutation-induetion was increased much stronger than UV-inactivation. The sensitization factors were different for the three mutation types and highest at low UV-doses (3.4, 5.0 and 22 for c, b and e resp.). The UV-dose curves of mutation induction in normal are of the 2 hit type, but for BU- they were significantly less curved indicating the participation of 1-hit-processes in premutation production. It is concluded that inhibition of dark repair (HCR) of lethal lesions and premutations in BU-DNA is not the only reason for the differences in UV-sensitivities but that production of other species of UV-products in BU-DNA than in normal DNA plays also a role.
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Using a Phillipson microbomb calorimeter, the energy values of the “infauna-substrate-feeders”Sipunculus nudus andPhascolosoma vulgare and the nutritive value of their food substrate were determined. Calorific measurements were made of the total food substrate, of meiofauna organisms living in it and of fecal pellets from other invertebrate animals which are an important part in the food supply. Analyses of the gut content of the sipunculids and their feces were compared with the surrounding sediment. The total sediment had an ash content of about 97%, and an energy content of approximately 0.14 cal mg?1 dry weight; this is equivalent to 165 kcal m?2. For the meiofauna in this substrate a biomass of 800 mg dry weight was calculated. Using calorific determinations of important meiofauna groups (nematodes 5274 kcal kg?1, ostracods 5884 and 6000 kcal kg?1), one square meter of the sediment surface — the sipunculid food source — yielded a caloric content of 3.78 kcal for the meiofauna, which means a contribution of 2.3% to the total food substrate. The largest part of the calorific contents is by far provided by fecal pellets with 0.6 cal mg?1 dry weight or 150 kcal m?2; this accounts for 92% of the total calorific content of the food substrate. Peritrophic membranes and attached microorganisms may be responsible for this spectacularly high value. Coprophagy plays an important role. The rest of the total value was contributed by particulate and dissolved detritus as well as protozoans with a calculated sum of 10 kcal m?2 or 6%. Food uptake is selective with regard to small sediment grain sizes. The amount of meiofauna in the gut is 80 times lower than in the surrounding environment, the energy content in the anterior gut 10 times higher. The energy loss inS. nudus from the anterior gut to the middle gut is more than 70%, to the posterior gut a further loss of 19% was observed. Calorific measurements in the feces were no longer possible. The utilization of food appears to be almost 100%. A correlation between ash content and the quantity of the sand grain-size fraction 37–125 μm and the calorific content is shown. The meiofauna does not represent a significant part of the total food structure, but it is taken up and utilized as food by the sediment feeding macrofauna.  相似文献   

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