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51.
52.
Summary Linear measurement of blocks of constitutive heterochromatin and the euchromatin portion 1q-h in three members of a family was used to study the dependence of the size of C blocks on the degree of chromosomal contraction. The results demonstrate that the size of heterochromatin portions decrease regularly with an increases of the degree of euchromatin contraction. The dependence was found to be linear, except for mitoses with an extremely high or low degree of contraction. The finding was used for the development of a new method of evaluation of constitutive heterochromatin. 相似文献
53.
Summary The kinetics of cell division and sister chromatid exchanges were studied in PHA-stimulated short-term cultivations of peripheral blood by means of the BUDR/FPG technique in controls and in five patients with 45,X/46,X,i(Xq) mosaicism. No significant differences in the length of the cell cycle were observed between 45,X/46,X,i(Xq) and control 46,XX cells. The number of SCE on late i(Xq) was only nonsignificantly elevated (0.6 per i(Xq)) against the value expected on the basis of its relative length. 相似文献
54.
55.
The effects of glucose, glucose metabolites, protein-enriched rete testis fluid (RTF), selected androgens and phospholipids on the survival of testicular spermatozoa have been studied. The oxidative and glycolytic activity, motility and percentage of live cells were the criteria for assessing the viability of the spermatozoa washed free of the substances that had been added during storage. The addition of lithium lactate, sodium lactate and sodium pyruvate but not glucose was beneficial to the survival of testicular spermatozoa. Following 10 to 12 days storage at 4°C with added lactate or pyruvate testicular spermatozoa had a higher glycolytic activity than did control spermatozoa. The respiratory activity of stored testicular spermatozoa was maintained or depressed, depending on the density of spermatozoal suspension during storage. After 10 to 11 days storage in concentrated RTF or after exposure to selected androgens testicular spermatozoa utilized more glucose than after storage with lactate alone. However, this apparent response to androgens and RTF-proteins was the consequence of a higher survival rate of the spermatozoa rather than an increase in the metabolic activity of individual spermatozoa. These results indicate that metabolites of glucose may serve as substrates for spermatozoa in the epididymis while certain androgens and macromolecules occurring in reproductive tract fluids may play important roles in the survival of spermatozoa during their period of maturation in the epididymis. 相似文献
56.
Epididymal fluid may contain substances which promote development of the fertilizing capacity of testicular spermatozoa under in vitro conditions, provided that the spermatozoa are exposed to such substances for long periods of time. In an attempt to resolve this question, the fertilizing capacity of testicular spermatozoa was assessed before and after storage in cauda epididymal fluid and comparisons made with ejaculated spermatozoa from the same rams. Of the 13 eggs examined from the group of ewes inseminated with ejaculated spermatozoa 61.5% were found to be in the 2-to 8-cell stage. No fertilized eggs were recovered from ewes impregnated with freshly collected testicular spermatozoa. Nor were any cleaved eggs obtained from the group of ewes inseminated with testicular spermatozoa stored in cauda epididymal fluid at 4°C for 7 to 11 days. We suggest there-fore, that in order to develop maximal fertilizing capacity, mammalian spermatozoa must be exposed to specific concentrated testicular and epididymal secretions in a sequential order and within strict time limits. 相似文献
57.
Josef Bogner 《Plant Systematics and Evolution》1983,142(1-2):49-55
The new speciesH. lucens Bogner differs fromH. truncatum (M. Hotta)Bogner etNicolson: The leaf blades are narrower, the spadix is adnate to the spathe for two third of its length, i.e. with all of its female and half of its male part. The latter has (fertile) stamens only on its front and staminodes on its back side. Further staminodes occur between the male and female flowers. 相似文献
58.
Jan Kopecký Jir̆i Dĕdina Jaroslav Votruba Petr Svoboda Josef Hous̆tĕk Sergej Babitch Zdenĕk Drahota 《BBA》1982,680(1):80-87
1. The oligomeric dicyclohexylcarbodiimide (DCCD)-binding protein of mitochondrial ATPase was studied using (a) the relationship between [14C]DCCD binding and inhibition of ATPase activities and (b) the analysis of the kinetics of inhibition. 2. The [14C]DCCD binding to bovine heart mitochondria is linearly proportional to the inhibition of ATP hydrolysis up to a 50% decrease of the original activity resulting in 0.6 mol DCCD bound covalently to the specific inhibitory site (Hous?t?k, J., Svoboda, P., Kopecký, J., Kuz?ela, S?. and Drahota, Z. (1981) Biochim. Biophys. Acta 634, 331–339) per mol of the fully inhibited enzyme. 3. Kinetics of the inhibition of both the ATPase activity (heart and liver mitochondria) and ADP-stimulated respiration (liver) reveal that 1 mol DCCD per mol ATPase eliminates both the synthetic and the hydrolytic activities. It is inferred that the activity-binding correlation underestimates the number of DCCD-reactive sites. 4. The second-order rate constant of the DCCD-ATPase interaction (k) is inversely related to the concentration of membranes, indicating that DCCD reaches the inhibitory site by concentrating in the hydrophobic (phospholipid) environment. 5. At a given concentration of liver mitochondria, comparable k values are obtained both for the inhibition of ATP hydrolysis (k=5.35·102M?1·min?1) and ADP-stimulated respiration (k=5.67·102M?1·min?1). 6. It is concluded that both the synthetic and the hydrolytic functions of ATPase are inhibited via a common single DCCD-reactive site. This site is represented by one of the several polypeptide chains forming the oligomer of the DCCD-binding protein. The inhibitor-ATPase interaction does not exhibit cooperativity, indicating that the preferential reactivity towards DCCD is an inherent property of the inhibitory site. 相似文献
59.
Josef Holub 《Folia Geobotanica》1983,18(2):203-206
On the basis of taxonomic and nomenclatural revisions of various plant groups 37 new nomenclatural combinations are proposed mostly for European phanerogamous taxa (21 for species, 14 for subspecies, 2 for hybrids.)Medicula Medicus,Pseudofumaria Medicus andThlasidia Rafin. are accepted as taxonomically justified genera and correct generic names.Dactylorhiza longebracteata (F. W. Schmidt)Holub is proposed instead ofD. fuchsii (Druce) Soó, andHylotelephium triphyllum (Haworth) Holub isstead ofH. purpureum (L.)Holub. 相似文献
60.
Josef Holub 《Folia Geobotanica》1983,18(3):325-328
A list including 114 selected subspecies names from the bookSchübler andMartens, Flora von Würtemberg, 1834 is given. Twenty of them are very important for the present taxonomic classification. 相似文献