Über die Abhängigkeit der Tumor-Entwicklung vom Wirtsorganismus beim bakteriellen Pflanzenkrebs     

Uwe Karsten 《Genetic Resources and Crop Evolution》1965,13(1):737-761

Zusammenfassung Wachstumskurven vom bakteriellen Pflanzenkrebs (crown gall) an verschiedenen Wirtspflanzen (Pelargonium-Arten,Vicia faba, Bryophyllum daigremontianum) zeigen einen Verlauf, der dem anderer biologischer Wachstumsvorgänge außerordentlich ähnlich ist. In den Kurven verschiedener Sippen kommen genetisch bedingte Einflüsse des Wirtsorganismus auf die Tumorentwicklung zum Ausdruck. Sogar die Partnergewebe von Periklinalchimären können in dieser Beziehung unterschiedlich reagieren. Die Kurven schnell wachsender Tumoren nähern sich einer Grenzkurve, die als die Wachstumskurve voll alterierter Tumoren anzusehen ist. Bei Sippen mit langsam wachsenden Tumoren ist häufig die Anfangsphase gehemmt. Tumoranfälligkeit und Tumorwüchsigkeit sind in der Regel gleichsinnig beeinflußt.Mit dem Aufhören des Streckungswachstums entstehen weniger und kleinere Tumoren (Bryophyllum-Blätter,Vicia). Kinetin macht ältere Blätter vonBryophyllum nicht anfälliger. Die heranwachsenden Brutknospen hemmen die Entwicklung von Tumoren an den Blättern. Dekapitieren der Pflanzen fördert dagegen die Tumoren und überdeckt den Hemmungseffekt der Brutknospen. Diese und andere Versuche zeigen, daß pflanzliche Tumoren während der Induktionsphase und in geringerem Ausmaß auch noch später durch physiologische Mechanismen beeinflußbar sind.

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Summary Growth diagrams of crown gall tumors on different host plants (species ofPelargonium, Vicia faba, Bryophyllum daigremontianum) are very similar to those of other biological growth processes. Curves of different taxa reveal that development of tumors is influenced by the genetic constitution of host organism. Even partner-tissues of periclinal chimerae may react differently. Curves of rapidly growing tumors approach a limit which should be regarded as growth curve of fully alterated tumors. The initial phase of slowly growing tumors is often retarded. Sensitiveness to tumors and growth of tumors usually are influenced simultaneously.With the end of leaf growth fewer and smaller tumors arise (Bryophyllum-leaves,Vicia). Kinetin does not increase sensitivity to tumors in older leaves ofBryophyllum. Growing adventitious leaf-buds retard tumor development in leaves. Decapitating of plants favours tumors and covers the retarding effect of leaf buds. These and other experiments show that plant tumors may be influenced by physiological mechanisms during the inductive phase, and, though to a lesser extent, also later on.

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Osmotic potentials of roots of onions and their rhizospheric soil solutions when irrigated with saline drainage waters     

U Schleiff 《Agricultural Water Management》1981,3(4):317-323

In the field experiments with onions in Hofuf, Saudi Arabia, the effect was investigated of irrigations with saline water having 2.3–8.0 mS cm^?1 on the Cl^? content of the soil close to the roots.Immediately after water application the rhizospheric soil contained 3–4.5 meq Cl^?/100 g, which was 3–5 times more than the remainder of the soil. After 4 days of water depletion 9–11 meq Cl^?/100 g were found in the rhizospheric soil, whereas the soil far from the roots contained only 0.5–1.5 meq Cl^?/100 g. The osmotic potentials of the rhizospheric soil solutions ranged from ?0.5 MPa to ?0.9 MPa after water application and from ?2.0 to ?3.0 MPa 4 days later. The differences in the salt contents of the rhizospheric soil were much lower than expected from the large differences in the salt concentrations of the irrigation water.  相似文献   

Prevalence of antibodies against feline panleukopenia virus in client-owned cats in Southern Germany     

Katherina Mende  Bianca Stuetzer  Carola Sauter-Louis  Timo Homeier  Uwe Truyen  Katrin Hartmann 《Veterinary journal (London, England : 1997)》2014,199(3):419-423

Feline panleukopenia is a frequent and commonly fatal disease of cats. Recent published studies have raised suspicions that some cats fail to develop antibodies after vaccination. The purpose of this study was to assess the prevalence of antibodies against feline panleukopenia virus (FPV) in cats in Southern Germany, and to identify factors that are associated with a lack of antibodies. In total, 350 cats presented to the Clinic of Small Animal Medicine, Ludwig-Maximilians-Universitaet were randomly included in the study. Information regarding signalment, origin, environment, lifestyle, housing conditions, health status, chronic diseases, glucocorticoid therapy, and vaccination status were collected. Antibodies were detected by haemagglutination inhibition test. Asymptomatic chi-squared tests and univariable logistic regression were used to investigate associations between a lack of antibodies and the different variables. Associations determined to be statistically significant at P < 0.1 were verified by a multivariable logistic regression analysis.Of the 350 cats, 103 (29.4%) had no antibodies against FPV. Chronic kidney disease, neoplasia, glucocorticoid therapy, and vaccination status were significantly associated with a lack of antibodies. The cats with no antibodies were likely to have inadequate immunity against panleukopenia and those with chronic diseases or receiving glucocorticoids were less likely to be protected.  相似文献   

Specific GABAA circuits for visual cortical plasticity     

Fagiolini M  Fritschy JM  Löw K  Möhler H  Rudolph U  Hensch TK 《Science (New York, N.Y.)》2004,303(5664):1681-1683

Weak inhibition within visual cortex early in life prevents experience-dependent plasticity. Loss of responsiveness to an eye deprived of vision can be initiated prematurely by enhancing gamma-aminobutyric acid (GABA)-mediated transmission with benzodiazepines. Here, we use a mouse "knockin" mutation to alpha subunits that renders individual GABA type A (GABA(A)) receptors insensitive to diazepam to show that a particular inhibitory network controls expression of the critical period. Only alpha1-containing circuits were found to drive cortical plasticity, whereas alpha2-enriched connections separately regulated neuronal firing. This dissociation carries implications for models of brain development and the safe design of benzodiazepines for use in infants.  相似文献   

Maplike representation of celestial E-vector orientations in the brain of an insect     

Heinze S  Homberg U 《Science (New York, N.Y.)》2007,315(5814):995-997

For many insects, the polarization pattern of the blue sky serves as a compass cue for spatial navigation. E-vector orientations are detected by photoreceptors in a dorsal rim area of the eye. Polarized-light signals from both eyes are finally integrated in the central complex, a brain area consisting of two subunits, the protocerebral bridge and the central body. Here we show that a topographic representation of zenithal E-vector orientations underlies the columnar organization of the protocerebral bridge in a locust. The maplike arrangement is highly suited to signal head orientation under the open sky.  相似文献   

Simulation of chromium transport in the unsaturated zone for predicting contaminant entries into the groundwater     

Uwe Buczko  Luisa Hopp  Wolfgang Berger  Wolfgang Durner  Stefan Peiffer  Markus Scheithauer 《植物养料与土壤学杂志》2004,167(3):284-292

Heavy metal contaminations in the top‐soil layers can impose serious threats to groundwater quality. A seepage water prognosis of probable future contaminant entries at the groundwater surface has to take into account the emission characteristics of the source zone and the reactive transport of the contaminated leachate through the unsaturated zone. Here, a possible approach is presented, exemplarily for a site contaminated with chromium, encompassing batch elution experiments, unsaturated soil column leaching experiments with flow interruption, soil monolith lysimeter experiments, and numerical modeling of non‐equilibrium solute transport. The prognosis provides a long‐term prediction of Cr concentrations at the groundwater surface. It must be emphasized, that the modeling results are uncertain, because several of the parameters in the simulations can be determined only with significant errors. Additionally, the approach is not applicable routinely for every hazardous waste site. Our study reveals, however, that reactive contaminants can possibly reach the groundwater at hazardous concentrations within very short time.  相似文献   

Microbial diversity in three floodplain soils at the Elbe River (Germany)     

Jörg Rinklebe  Uwe Langer 《Soil biology & biochemistry》2006,38(8):2144-2151

Microbial communities in floodplain soils are exposed to periodical flooding. A long-term submerged Eutric Gleysol (GLe), an intermediate flooded Eutric Fluvisol (FLe), and a short-time flooded Mollic Fluvisol (FLm) at the Elbe River (Germany) with similar organic carbon contents (C_org) between 8.1% and 8.9% were selected to test the quality of phospholipid fatty acids (PLFA), soil microbial carbon (C_mic), basal respiration (BR), metabolic quotient (qCO₂), and C_mic/C_org ratio to characterize and discriminate these soils with microbial parameters.The three floodplain soils can be differentiated by C_mic and by total PLFA-biomass. Due to the different flooding durations and the time since the soils were last flooded C_mic and PLFA-biomass increase in the order GLe<FLe<FLm. Both parameters correlate significantly (r=0.999;p<0.05). The C_mic/C_org ratios are low in comparison to terrestrial soils and revealed the same ranking over the three soils like C_mic. Contrary, qCO₂ and BR are highest in GLe and lowest in FLm according to inundation regime. The diminished C_mic, high BR, and high qCO₂ values in GLe seem to be an unspecific response of aerobic soil microorganisms on the long flooding period and the resulting short time for developing after last flooding as well as the low pH value. Different plant communities and their residues may influence the microbial diversity additionally.The PLFA profiles were dominated by the group of saturated fatty acids that together constituted almost 62-72% of the total fatty acids identified in the soils. In GLe all groups of PLFA, inclusive monounsaturated fatty acids, are lowest and in FLm highest, while in FLe the PLFA fractions show an intermediary amount of the three soils. The FLm had most of the time aerobic conditions and revealed therefore the highest C_mic, PLFA-biomass, especially monounsaturated fatty acids, C_mic/C_org ratio as well as relatively low BR and qCO₂ value. These indicate that microorganisms in FLm are more efficiently in using carbon sources than those in GLe and FLe.All 26 identified PLFA were found in FLe and FLm, while the polyunsaturated fungi biomarker 18:2ω6,9c could not be detected in GLe. In this long-time submerged soil the environmental conditions which microorganisms are exposed might be disadvantageous for fungi.  相似文献   

Die Bestimmung der Wasserspannungs- /Wasserleitfähigkeits-Beziehung von Bodenaggregaten     

Michael Gunzelmann  Uwe Hell  Rainer Horn 《植物养料与土壤学杂志》1987,150(6):400-402

Determination of the unsaturated hydraulic conductivity of soil aggregates by use of microtensiometers The hydraulic properties of single aggregates were measured with the use of microtensiometers. They are small enough (tip diameter 1 mm, length 1–2 mm) that two of them can be installed inside an aggregate within a distance of 1–3 mm. The changes of water suction are measured with pressure transducers and recorded by a micro-computer. Results obtained for different aggregates show, that at the same water suction, the hydraulic conductivity of single aggregates is up to 2 orders of magnitude smaller than that of the bulk soil. The cross-over-suction value for aggregates can also be derived.  相似文献   

Bestimmung der Gehalte an osmotisch wirksamen Substanzen in Pflanzen     

U. Schleiff 《植物养料与土壤学杂志》1981,144(4):335-338

Determination of osmotically effective substances in plants A simple method is proposed for the determination of the osmotic potential ψo in leaves of plants grown in saline soils. The ψo-value of the leaf sap is determined from the water content of the fresh leaves and its content of osmotically effective substances (OWS) determined in the ground dry matter of the leaves. The OWS-content is measured cryoscopically in 0,5% acetic acid (30 ml/1g DM). The ψo-value of the leaf sap is obtained by relating the OWS-contents to the leaf water contents of the fresh matter.  相似文献   

Chloride content of onion roots and their adhering soil under irrigation with saline drainage water     

U. Schleiff 《植物养料与土壤学杂志》1980,143(6):638-644

Water depletion by plants in saline soils leads to the accumulation of salts in the soil in the close vicinity of the roots (= rhizopheric soil). CI^?/l. After a period of 4 days water depletion the Cl–contents of 2,5 to 4, s me CI^?/ 100 g soil were found in the rhizospheric soil of onions immediately after a water application, when irrigated with water containing 13 to 52 me Cl–content increased in the rhizospheric soil 3-4 fold up to 12 me CI^?/100 g soil corresponding to a CI–concentration in the rhizospheric soil solution of 800 me Cl-L The differences between the irrigation treatments were small. The CI–contents of the roots in this experiment varied from 1,2-1,9 me CT/g DM. When expressing the Cl–contents in terms of the cell sap of the roots, CI–concentrations of 1OC-200 me CI^?/I cell sap were abtained at a root water content of 90 %. Assuming a decrease in the root water contents to 70 % after a water depletion period of 4 days. CT-concentrations of 500-800 me Cl-ll cell sap are obtained, which corresponded to CI-concentrations determined in the rhizospheric soil solution.  相似文献