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941.
942.
Dierk Franck Jürgen Marek Wolfgang Winter 《Ethology : formerly Zeitschrift fur Tierpsychologie》1978,46(2):170-183
After 14 days of social isolation, half-grown Poecilia sphenops still showed no sexual activity but an increase in biting and tail beating. In relation to this result data on diurnal rhythms of the observed activities, the biological significance of the aggressivity in immature fish, and the ontogeny of the aggressive and sexual behaviour are presented. In contrast to the aggressive behaviour no sexual activity could be observed before maturity. 相似文献
943.
Continuous dependence of spatially nonuniform concentration profiles for the 'Brussellator" reaction mechanims on the characteristic length of the system is given both for zero flux and fixed boundary conditions. Branches of solutions arising through primary bifurcation form closed curves. Secondary bifurcations giving rise to spatially asymmetric solutions exist for fixed boundary conditions. Results of a stability analysis of individual solutions are discussed. A method of composing complex spatial profiles for higher lengths from elementary solutions for smaller lenghts is suggested and tested in the case of zero flux boundary conditions. Emergence of subsequently more complex stable patterns in dependence on increasing length of the system suggests many similarities to gradual build up of complex morphogenetic patterns. 相似文献
944.
Summary The influence of gonadotropic hormones on the ultrastructure of rat pinealocytes was studied. Human chorionic gonadotropin (HCG) as well as pregnant mare serum gonadotropin (PMSG) caused a marked activation of pinealocytes. It is characterised by a conspicuous proliferation of the granular endoplasmic reticulum and Golgi apparatus as well as an increase in number of dense core vesicles, mitochondria, dense bodies, subsurface cisternae and vesicles in the terminal buds of pinealocyte processes. The changes after HCG administration were more pronounced than after PMSG.Supported by a grant from the Polish Academy of Sciences, No. 10.4.2.01.5.6 相似文献
945.
946.
Starting from methyl 4,6-dichloro-4,6-dideoxy-α-D-galactopyranoside (1), D-chalcose (4,6-dideoxy-3-O-methyl-D-xcylo-hexopyranose) (5) was prepared by dechlorination with tributyltin hydride, selective benzoylation with benzoyl cyanide at O-2, methylation at O-3, and acid hydrolysis. D-Chalcose (5) was obtained as well by direct methylation of 1 with diazomethane at O-3, reduction with tin hydride, and hydrolysis. Chalcosyl bromide prepared from 5 was not very suitable for β-glycoside synthesis under Koenigs-Knorr conditions, and better results were obtained with 2- O-acetyl-4,6-dichloro-4,6-dideoxy-3-O-methyl-α-D-galactopyranosyl bromide, which gave β-glycosides with methanol, cyclohexanol, benzyl alcohol, 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose, and methyl 2,3-di-O-benzyl-6-deoxy-α-D-glucopyranoside. After dechlorination with tributyltin hydride, the corresponding β-glycosides of D-chalcose were obtained in good yield. 相似文献
947.
948.
Rachel E. Milner Konrad S. Famulski Marek Michalak 《Molecular and cellular biochemistry》1992,112(1):1-13
In this paper we review some of the large quantities of information currently available concerning the identification, structure and function of Ca2+-binding proteins of endoplasmic and sarcoplasmic reticulum membranes. The review places particular emphasis on identification and discussion of Ca2+ storage proteins in these membranes. We believe that the evidence reviewed here supports the contention that the Ca2+-binding capacity of both calsequestrin and calreticulin favor their contribution as the major Ca2+-binding proteins of muscle and nonmuscle cells, respectively. Other Ca2+-binding proteins discovered in both endoplasmic reticulum and sarcoplasmic reticulum membranes probably contribute to the overall Ca2+ storage capacity of these membrane organelles, and they also play other important functional role such as posttranslational modification of newly synthesized proteins, a cytoskeletal (structural) function, or movement of Ca2+ within the lumen of the sarcoplasmic/endoplasmic reticulum towards the storage sites.Abbreviations SR
Sarcoplasmic Reticulum
- ER
Endoplasmic Reticulum
- InsP3
Inositol 1,4,5-trisphosphate
- SDS-PAGE
Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis
- PDI
Protein Disulphide Isomerase
- T3BP
Thyroid Hormone Binding Protein
- Grp
Glucose regulated proteins
- HCP
Histidine-rich Ca2+ binding Protein
- LDL
Low Density Lipoprotein 相似文献
949.
Summary Calreticulin was identified in a variety of rabbit tissues by Western blot analysis. Indirect immunofluorescence studies on cultured cells or frozen sections from the corresponding tissues revealed that the protein was distributed to the endoplasmic reticulum or sarcoplasmic reticulum. Calreticulin was found to be an abundant calcium-binding protein in non-muscle and smooth muscle cells and a constitutent calcium-binding protein in cardiac and skeletal muscle. From the immunoblot data, calreticulin may exist as an isoform in rabbit neural retina. The present study establishes the ubiquity of calreticulin in intracellular calcium binding. 相似文献
950.
Photosynthesis and photorespiration in presenescent, senescent, and rejuvenated soybean cotyledons 总被引:1,自引:0,他引:1
Various growth and physiological parameters were measured in germinating, presenescent, and senescing soybean (Glycine max [L.] Merr.) cotyledons and in cotyledons rejuvenated by epicotyl removal 18 days after planting. The maximal measured carbon dioxide exchange rates (CER) in the cotyledons were in the range of those reported for field-grown soybean leaves. Rejuvenated cotyledons accumulated total chlorophyll in excess of the maximum observed in presenescent cotyledons. When photosynthetic rates were expressed per cotyledon, the CER in rejuvenated tissue recovered to the maximal rates observed in presenescent cotyledons. Ribulose-1,5-bisphosphate carboxylase/oxygenase in rejuvenated cotyledons also recovered to the maximal amount seen in presenescent cotyledons so that CER appeared to be a function of ribulose-1,5-bisphosphate carboxylase/oxygenase content during most of the period studied. Observations of the postillumination outburst of CO2 and 14C label in glycine indicated that photorespiration was occurring in the cotyledons and that photorespiration relative to photosynthesis was different in rejuvenated compared with presenescent cotyledons. 相似文献