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141.
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
142.
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
143.
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
144.
145.
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
146.
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
147.
The idiotopic (Id) repertoire of antibody response to phosphocholine was studied in mouse strains with different IgH allotypes. The T15 idiotype-bearing (T15+) serum antibody and antibody plaque-forming cells (PFC) were characterized with four monoclonal anti-Id that recognize distinct Id determinants on T15+ antibody encoded by VH-1 (of the S107 gene family), DH FL16.1, JH-1 and Vk22 germ-line genes. We have previously shown that expression of the Id designated AB1-2 and B36-82 depends on the third hypervariable loop (D region), whereas the other Id, MaId5-4 and B24-44, are influenced by VH structures outside of the D region. All four Id were expressed in the PC-response of all mouse strains tested, except the Ighj strains (C3H/HeJ, CBA/H-T6, PL/j), where the D region-dependent Id, AB1-2 and B36-82, were absent. The other Id, however, were normally expressed on individual PFC as well as the serum antibody of the Ighj strains. Expression of AB1-2 and B36-82 on 50% of PFC occurred in (BALB/c-Igha x C3H/HeJ-Ighj)F1 mice. The absence of Id correlated with a unique RFLP of the S107 gene family in Ighj strains. Finally, Id expression segregated with the appropriate RFLP pattern in individual (BALB/c x C3H/HeJ)F2 mice. These data demonstrate a selective genetic linkage of discrete T15 Id determinants, AB1-2 and B36-82 with the Igh allotype. By comparing these results with the available Ig sequences, we suggest that the Ighj allotype may be associated with an allelic form of the DH-FL16.1 segment which with VH-1, JH-1, and the Vk 22 code for the phosphocholine-specific antibody in the mouse. 相似文献
148.
Summary Rates of insect capture increased with leaf area in the insectivorous plant Drosera rotundifolia, and growth of new leaves was related to insect capture. However, increased leaf growth was counterbalanced by leaf abscission which was in turn related to insect capture and leaf growth. Leaf loss equaled leaf growth in plants having natural rate of insect capture. A large proportion of the nitrogen gain from prey was stored in the hypocotyl; it was estimated from feeding experiments that about 24% to 30% of the nitrogen stored in the hypocotyl after winter originated from insect capture in the previous season. The effect of insect capture is discussed in relation to the life cycle of Drosera. 相似文献
149.
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
150.