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91.
In halt: 1. Einleitung und Aufgabenstellung.—2. Art und Ausmaß der Scnäden im Feld-versuch.—3. Wirkungen des Krankheitserregers auf Sommergetreide.—4. Bekämpfungsmöglichkeiten.—5. Besprechung der Ergebnisse.—Zusammenfassung.—Summary. —Literaturverzeichnis. 相似文献
92.
Unexposed blanks prepared from Kodak AR 10 stripping film were dried by 3 methods: (1) fast, open drying with a fan for 25 min, (2) slow drying in a desiccator for 6 hr, and (3) very slow drying in a desiccator for 24 hr. The number of background grains depended on the mode of drying. Fast drying (method 1) gave 0.7 grain per 100 μ2, slow drying (method 2) gave 0.33 grain; very slow drying (method 3), only 0.17 grain. The increase of background after fast drying is assumed to be caused by the rapid shrinkage of wet emulsion. This causes an increase in the intraemulsion pressure which, in turn, sensitizes the silver bromide crystals to cause an increase in the number of developable grains. 相似文献
93.
Sandro Cavicchi Daniela Guerra Vanna Natali Cristina Pezzoli Gianfranco Giorgi 《Journal of evolutionary biology》1989,2(4):235-251
From a laboratory stock of Drosophila melanogaster (Oregon), reared for more than 20 years at 18° C, a new population was derived and maintained at 28° C for 8 years. The chromosomal and cytoplasmic contribution to genetic divergence between the two populations was estimated. Six body traits and reproductive fitness were taken into account. The third chromosome is responsible for the adaptive difference for temperature between the two lines. Temperature-selected genes which control body size are located on the second and third chromosomes, although the contribution of each chromosome depends on the environment in which the flies develop. The correlation between the chromosomal and cytoplasmic contributions to different traits and fitness, changes with temperature. At 28° C the correlation between fitness and each body trait is proportional to the response to selection exhibited by each of them, but this is not true at 18° C. Body size has, therefore, an adaptive significance in relation to temperature, which is expressed only in the environment where selection occurs. Cytoplasmic genes affect almost all characters to an extent similar to that of chromosomal genes. Inter-chromosomal and nucleo-cytoplasmic interactions are present and also change with temperature. In general, genes selected in a given environment produce greater phenotypic changes in that environment than in another. The population that experienced both temperatures is fitter in both environments, suggesting that the capacity to adapt to warm temperatures depends on genes other than those which are involved in the adaptation to cold. 相似文献
94.
The pectinolytic enzyme of Selenomonas ruminantium 总被引:1,自引:0,他引:1
Kvetoslava Heinrichova Maria Wojciechowicz A. Ziolecki 《Journal of applied microbiology》1989,66(2):169-174
A cell-bound pectinolytic enzyme was isolated from cells of Selenomonas ruminantium and purified about 360-fold. The optimum pH and temperature for enzyme activity was 7.0 and 40°. The enzyme degraded polymeric substrates by hydrolysis of digalacturonic acid units from the non-reducing end; the best substrate was nona-galacturonic acid. Unsaturated trigalacturonate was also degraded, but 30% slower than the saturated analogue. The enzyme was classified as a poly (1,4-aP-D-galactosiduronate) digalacturono-hydrolase; EC 3.2.1.82. Another enzyme, hydrolysing digalacturonic acid to monomers, was also produced in a very small amount by this organism. 相似文献
95.
Effects of Solar Radiation on Photoorientation,Motility and Pigmentation in a Freshwater Cryptomonas
The effects of solar radiation on motility, photoorientation and pigmentation have been studied in a freshwater Cryptomonas species. The diaphototactic orientation performed by the cells is impaired within about 90 min of solar radiation. Likewise, the percentage of motile cells within the population and the average velocity of the swimming cells decreases within about the same exposure time. This effect is not due to a thermal stress but rather seems to be caused by the solar UV-B component, since decreasing short wavelength UV radiation by means of an artificial ozone filter or UV cut-off filters increased the tolerated exposure time. Solar radiation also bleached the photosynthetic pigments of the cells as shown by absorption difference spectra. 相似文献
96.
Prof. Dr. Renate Koenig Maria Rüdel Dr. D.-E. Lesemann 《Journal of Phytopathology》1989,127(2):169-172
A number of virus isolates were obtained from ditches and drainage canals in the Palatinate grapevine-growing area (‘Rheinpfalz’) in West Germany. By means of the immunoelectron microscopical decoration and the agar gel double diffusion tests these isolates were identified as petunia asteroid mosaic virus, carnation ringspot virus and tobacco necrosis virus strain D, respectively. 相似文献
97.
Dr. María Cristina Maldonado Ana María Strasser de Saad Danley Callieri 《Current microbiology》1989,18(5):303-306
Several recent reports have described large numbers of monoclonal antibodies that cross-react with toxins A and B ofClostridium difficile; this suggests that the toxins share major epitopes. Our results show that monoclonal antibodies (MAb) against other antigens bind nonspecifically to both toxins. Therefore, we believe that the cross-reacting MAb bind by this manner and not by a true immune reaction. 相似文献
98.
Pier Giorgio Borasio Carla Biondi Maria Enrica Ferretti Elena Fabbri Maria Cristina Pareschi 《Neurochemical research》1989,14(12):1181-1186
Agonists modulation of Mg2+-dependent adenylate cyclase activity has been studied in guinea-pig superior cervical ganglion crude membrane preparations. In the absence of receptors ligands, Mg2+ stimulates the enzyme in a concentration-dependent manner. The dose-activation curve shows heterogeneity and two components with higher and lower apparent affinity states, are extrapolated. In the presence ofD-Ala2-met-enkephalinamide only one component is present and the apparent affinity of the ganglionic adenylate cyclase system for the divalent cation as well as Vmax are inhibited. On the contrary, prostaglandin E2 increases affinity and Vmax values of the lower and, to a lesser extent, of the higher Km component. When the two drugs are tested in combination, not only the inhibitory effect of the opiate is overcome, but a large increase of the apparent affinities and Vmax values for both components is obtained, suggesting the involvement of the Mg2+-regulated subunits of the adenylate cyclase system in the supra-additive stimulation mechanism of the enzyme. 相似文献
99.
Stephen Francis Ferrari Maria Aparecida Lopes Ferrari 《Primates; journal of primatology》1990,31(3):323-338
The predator avoidance behaviour of a free-ranging group of buffy-headed marmosets,Callithrix flaviceps, was recorded in detail during the course of a long-term study of behavioural ecology at the Fazenda Montes Claros, southeastern
Brazil. Four distinct patterns of predator avoidance behaviour, each with specific vocalisations, were recognised and are
described here. The selection and use of sleeping sites by the study group are also described. An analysis of the records
indicates that these small monkeys are generally most vulnerable to predation by aerial raptors. Variations in the frequency
of alarm calls also indicate that the marmosets tend to be more vigilant at higher levels in the forest and when the leaf
cover is less extensive. The implications of group size and social structure for both the evolution and the efficacy of the
anti-predator behaviour of marmosets are also discussed. 相似文献
100.