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991.
992.
993.
Air-dried soil did not exhibit any measurable 1,3-β-D-glueanase activity. The enzyme activity was observed after a previous wetting of the soil or after supplementing it with glucose or caseine hydrolyzate. The addition of 1,3-β-D-glucan resulted in a significant increase of the enzyme activity in the variant with water and casein hydrolyzate but not in the variant treated with glucose. 相似文献
994.
V. Šunderlíková J. Salaj I. Matušíková E. Wilhelm 《Trees - Structure and Function》2009,23(1):135-144
995.
Jan Suda Radka Malcová Daniel Abazid Marek Banaš František Procházka Ota Šída Milan Štech 《Folia Geobotanica》2004,39(2):161-171
Ploidy levels inEmpetrum (crowberry) from the Czech Republic and from one adjacent locality in Poland were estimated by flow cytometry to examine cytotype distribution patterns at large (within the country), medium (within mountain ranges) and small (within particular localities) spatial scales. Diploid, triploid, and tetraploid individuals were found. Triploids are reported from Central Europe for the first time; they occurred in the Krkono?e Mts. Exclusively diploid plants were observed in three mountain ranges (the Kru?né hory Mts., Labské pískovce Mts., Adr?pa?sko-Teplické skály Mts.), exclusively tetraploids were observed in the Jeseníky Mts., and both cytotypes were observed in the ?umava Mts., Jizerské hory Mts. and Krkono?e Mts. Except for the latter mountain range, diploids and tetraploids were always found in different habitats. Spatial isolation is supposed to be the main barrier preventing cytotype mating. A mosaic-like sympatric occurrence of different cytotypes was demonstrated in the Krkono?e Mts., where peat bogs and rocky places were not spatially separated. Eight of 11 localities studied there were inhabited by diploids and tetraploids (five localities), diploids and triploids (one locality) or all three ploidy levels (two localities). Diploid and triploid plants occasionally intermingled at 0.3 × 0.3 m. Flower sex in crowberries was strongly associated with ploidy level: diploids usually had unisexual flowers, the tetraploids bore exclusively bisexual flowers. However, a few diploid plants with hermaphrodite flowers occurred in one population in the Krkono?e Mts. 相似文献
996.
The osmotic coefficients, heats of dilution, and volume changes on dilution of aqueous solutions containing mixtures of polystyrenesulfonic acid and its lanthanum salt have been determined at 25°C. The curve representing the osmotic coefficient as a function of the equivalent fraction of the acid has a maximum; the corresponding curves for the enthalpy and volume changes on dilution have a sigmoidal shape. Experimental results have been compared with predictions of the theory based on the cell model with cylindrical symmetry. A semiquantitative agreement between theory and experiment has been found. 相似文献
997.
Maria Sporbert Petr Keil Gunnar Seidler Helge Bruelheide Ute Jandt Svetlana Aćić Idoia Biurrun Juan Antonio Campos Andraž Čarni Milan Chytrý Renata Ćušterevska Jürgen Dengler Valentin Golub Florian Jansen Anna Kuzemko Jonathan Lenoir Corrado Marcenò Jesper Erenskjold Moeslund Aaron Pérez-Haase Solvita Rūsiņa Urban Šilc Ioannis Tsiripidris Vigdis Vandvik Kiril Vasilev Risto Virtanen Erik Welk 《Journal of Biogeography》2020,47(10):2210-2222
998.
The participation of cells from bone marrow and thymus in the antibody response to haptens was studied in two inbred strains of mice: poorly (CBA/J) and well (B10.LP) responding to immunization. The cell transfer experiments showed that the genetic regulation of the antihapten response under study, was bound directly to lymphatic cells of the immune system. For transfer of the good response it was essential that the thymus and bone marrow cell mixture contained bone marrow cells from well responding donors. Furthermore, the effect of endotoxin on antibody formation was studied in both well and poorly responding strains. It was found that endotoxin enhanced the antibody formation in both strains similarly so that the finεl differences between the levels of antibodies formed in both strains remained unchang d. Finally, it was demonstrated that endotoxin played the most important role in the primary stimulation, where the highest increase of the antibody response was obtained. 相似文献
999.
The lymphatic tissue of ileum, sacculus rotundus and appendix was poorly developed with-out germinal centres in germfree rabbits;
on the other hand, in conventional rabbits, the lymphatic tissue was abundant with numerous germinal centers. In germfree
rabbits, the stroma of villi of the jejunum and ileum possessed low cellularity, in conventional rabbits, the villi were wide
with rich cellularity. The basal position of lymphocytes was predominant in the villi of ileum of germfree rabbits, in conventional
rabbits a high percentage of lymphocytes was in the apical position. 相似文献
1000.
Ljiljana Ševaljević L. Svetozar Petrović David Rickwood 《Molecular and cellular biochemistry》1978,21(3):139-143
Summary Lysis of mitochondria from sea urchin embryos with Triton X-100 led to a complete conversion of DNA-containing mitochondrial residues into protein-DNA complex with a density higher than 1.22 g/cm3 in sucrose solutions. This complex banded isopycnically in metrizamide gradients at a density of 1..26 g/cm3. Exposure to mixtures of Triton X-100 with Tween 80 resulted in progressively less delipitated and disorganized mitochondria over Tween/Triton weight ratios from 1 to 2, with the retention of the starting buoyant density in sucrose of approximately 1.16 g/cm3 at Tween/Triton ratios above 2.5. The DNA-internal protein complex sedimented with the bulk of the surviving mitochondrial structure under all conditions studied. No free DNA could be detected under any conditions of membrane removal. 相似文献