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排序方式: 共有3264条查询结果,搜索用时 15 毫秒
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Drahomíra Kenov Lucie oltysov Michal Pravenec Marie-Pierre Moisan W. Theodore Kurtz Vladimír Ken 《Journal of Experimental Animal Science》2000,41(1-2)
The SHR-Lx congenic strain carrying a differential segment of chromosome 8 of BN and PD origin was recently shown to exhibit a significant decrease in blood pressure as compared to the SHR strain. There were two positional candidate genes for blood pressure control mapped to the differential segment: the rat kidney epithelial potassium channel gene (Kcnj1) and brain dopamine receptor 2 gene (Drd2). Bot these genes were separated into SHR.BN-RNO8 congenic substrains. In this communication, we are presenting the assignment of two further putative candidate genes, which might be involved in blood pressure control to the BN/PD differential segment of the SHR-Lx congenic strain. These are: the gene coding for smooth muscle cell specific protein 22 (Sm22) defined by the D8Mcw1 marker and neuronal nicotinic acetylcholine receptor gene cluster, defined by the D8Bord1 marker. Moreover, the glutamate receptor gene Grik4 which also maps to the differential segment of the SHR-Lx should be taken into account. The genetic separation of all these putative candidate genes of blood pressure control is being performed by recombinations and subsequent selection using (SHR×SHR-Lx) intercross population. 相似文献
3.
Michal Gadot Ouriel Faktor Shalom W. Applebaum 《Archives of insect biochemistry and physiology》1987,4(1):17-27
Reserpine, at doses of 20–175 μg per g body weight, severely retards oogenesis in newly emerged adult female migratory locusts (Locusta migratoria migratorioides) but does not increase mortality during the first 9 days and only slightly delays somatic growth. Total protein, and hemolymph vitellogenin content particularly, are significantly reduced in reserpine-treated locusts. The synthesis of juvenile hormone III (JH-III) following adult emergence, essential for induction of vitellogenesis and subsequent oogenesis, is dependent on the maturation and activation of the corpora allata (CA). CA of 7- to 8-day-old female locusts, treated with reserpine at day 1 after adult emergence, are only marginally active in vitro and are only slightly stimulated by an allatotropic factor. The basal activity and response of CA from the reserpine-treated locusts resembles that of newly emerged locusts, suggesting that reserpine specifically retards the initial maturation of the locust CA. Recovery of basal CA activity is evident on days 12–13 in reserpine-treated locusts, but responsiveness to the allatotropic factor is not recovered. Starvation of newly emerged females for 3 days and subsequent feeding did not effect ooctye development or CA activity. Cerebral content of the allatotropic factor, assayed on days 7–8, is not reduced by the reserpine treatment. 相似文献
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Michal Gadot Edina Burns Coby Schal 《Archives of insect biochemistry and physiology》1989,11(3):189-200
The roles of grouping and mating in modulating the activity of the corpora allata (CA) in adult female cockroaches were investigated using the in vitro radiochemical assay of juvenile hormone (JH) biosynthesis. Isolated virgin females have longer, asynchronous cycles of CA activity and oocyte maturation than do isolated females mated on day 8. Three factors were identified as the major contributors to this difference: (1) an experimental artifact of selection for sexually receptive females, (2) a positive effect of grouping on JH synthesis and oocyte maturation, and (3) a positive effect of copulation on oviposition and retention of the ootheca. Mated females constitute a subpopulation of receptive females that differ significantly from other females by having higher rates of JH synthesis prior to mating. The relative importance of such selection is substantial when the rate of mating is low, as in experiments with isolated females that are exposed to males for a short period of time. Long-term exposure of females to males introduces a grouping effect, which obscures any additional effect of mating on CA activity and oocyte development. However, mating influences ootheca formation and its retention. The effect of grouping can be mimicked in isolated females by transection of the nerves connecting the CA–corpora cardiaca complex to the brain, suggesting that in this insect isolation causes brain inhibition of the CA, and grouping provides disinhibitory stimuli that release the CA from brain inhibition. 相似文献
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Solid-phase synthesis of peptides was carried out using only the volume of the solvent included in the swollen solid-phase resin beads [inclusion volume synthesis]. This approach enables (i) the use of higher concentrations of activated amino acids, resulting in increased coupling rates, (ii) drastically decreased consumption of solvents, and (iii) the construction of multiple peptide synthesizers having virtually no reaction vessels. 相似文献
9.
I. Michalík 《Biologia Plantarum》1982,24(3):161-169
In an experiment with native maize roots depending on different phosphorus concentration in the external solution (0.001 …
50 mM P), the multiphasic character of the kinetics of phosphate uptake has been stated. The single phases are characterized
by the different values of Km and Vmax. In the wide range of concentrations the isotherm of the phosphate uptake has five evident phases. The character of kinetics
for the uptake of phosphate is analogical to the kinetics of the enzymatic reactions described by the Michaelis-Menten equation.
On the other hand the linear dependence for the inactivated root was determined,i.e. the uptake of phosphate versus different phosphorus concentration in the external solution.
The graphic representation of the logarithmic values for the phosphorus taken up versus the different phosphorus concentration
in the external solution gives the biphasic course including concentration less than 1.0 mM P and more than 1.0 mM P. Within
the framework of the concentration range the following values of Vmax, Km and ϕin were calculated under the conditions if the concentration of phosphorus is less than 1.0mMP: Vmax = 1.705 μmol P × g-1h-1, Km = 0.057 mM P and ϕin = 0.83,i.e. if the concentration of phosphorus is more than 1.0mM P: Vmax = 40 μmol P × g-1 h-1, Km = 16.66 mM and ϕin = 20.
According to these results, the phosphate concentration in the external solution influences the activity of the transport
mechanisms concerning their conformative changes which discretely change their working regime of membrane transport. This
is also demonstrated in the change of values Vmax, Km and ϕin. 相似文献
10.
Michal Pop 《Hydrobiologia》1991,225(1):169-176
The changes of selected parameters of the filtering comb of the third thoracic limb were studied in a natural population of Daphnia pulicaria Forbes, as well as in experimental enclosures and in lab cultures, including individual life history. Two hypotheses were tested: 1. either these changes are related to the succession of clones coexisting within one population, or 2. the size of the filtering area changes gradually as an individual adaptation during the moulting. No evidence supporting the clonal hypothesis was found. On the contrary, the adaptability of the filtering comb is the same in a natural population as it is in a clone and in individuals. 相似文献