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91.
DPI, a supposed selective agonist of inhibitory dopamine receptors, strongly increases rat diuresis through alpha-adrenergic receptor activation 总被引:1,自引:0,他引:1
The diuretic effect of dopamine (DA) was compared with that of other DA receptor stimulants in rats. While apomorphine (APO) and (±)N-n-propyl-norapomorphine (NPA) failed to increase urine excretion, (3, 4-dihydroxyphenylamino) -2-imidazoline (DPI), a supposed stmulant of DA inhibitory receptors, exerted a far greater diuretic efect than DA itself. The diuretic effect of DA and that of DPI were antagonized by a-adrenergic receptor antagonists such as phentolamine and yohimbine and by bulbocapnine. In contrast, DA receptor blockers such as haloperidol, pimozide, sulpiride and ergometrine were totally ineffective. It is concluded that the diuretic effect of DA and DPI are mediated by stimulation of a-adrenergic receptors. 相似文献
92.
Seed morphology and anatomy of Austrotaxus spicata (Taxaceae) and its systematic position 总被引:1,自引:0,他引:1
ALEXEY V. F. CH. BOBROV ALEXANDER P. MELIKIAN MIKHAIL S. ROMANOV ALEXEY N. SOROKIN 《Botanical journal of the Linnean Society. Linnean Society of London》2004,145(4):437-443
The anatomy and ultrastructure of seed envelopes of a New Caledonian endemic Austrotaxus spicata were examined for the first time. The systematic position and phylogenetic relations of Austrotaxus were analysed in light of these data. The structure of aril and spermoderm were investigated to demonstrate the similarities with Phyllocladus as well as with Taxus and Pseudotaxus . On the basis of all female reproductive organ characters, Austrotaxus appeared to be fairly isolated and its placing in the independent family Austrotaxaceae was confirmed from the standpoint of comparative anatomy of the seed coat. Taking into consideration that the heterobathmy of features can be the most distinctively traced in the structure of reproductive organs, evaluating the extent of evolutionary advancement of Austrotaxus seems to be rather difficult. However, it is evident that the relationship of Austrotaxus either with Taxaceae or with Podocarpaceae s.l . is considerably remote. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 437–443. 相似文献
93.
L Bordin G Clari B Baggio V Moret 《Biochemical and biophysical research communications》1992,187(2):853-858
In human erythrocytes Ser/Thr- and Tyr-phosphorylations of cytoplasmic domain of band 3 are catalyzed by casein kinase I and Tyr-protein kinase respectively, both distributed between cytosol and membrane structures. The results reported here show that purified cytosolic Tyr-protein kinase activity, assayed on added substrates such as poly(Glu,Tyr)4:1 and isolated chymotryptic fragments of band 3 cytoplasmic domain (cdb3), is potently inhibited by PIP and even more by PIP2. Similar inhibitory effects are displayed by these polyphosphoinositides also on the endogenous Tyr-phosphorylation of band 3, when they are added to the isolated native membranes, thus suggesting their involvement in regulating in-vivo Tyr-phosphorylation of membrane proteins. 相似文献
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95.
Structure and organization of the bovine beta-globin genes 总被引:1,自引:0,他引:1
Genomic clones spanning the entire cow beta-globin gene locus have been
isolated and characterized. These clones demonstrate that the linkage of
embryonic-like (epsilon) genes and pseudogenes (psi) to the previously
described fetal (gamma) and adult (beta) genes is as follows: 5'-epsilon
3-epsilon 4-psi 3-beta-epsilon 1-epsilon 2-psi 1- psi 2-gamma-3'. Present
data indicate that, like that of the goat, the fetal and adult genes arose
via block duplication of an ancestral four- gene set:
epsilon-epsilon-psi-beta. This duplication event preceded the divergence of
cows and goats, which occurred greater than or equal to 18-20 Myr ago.
However, cows do not have the additional four-gene block containing a
preadult/stress globin gene (beta C). Furthermore, the cow fetal cluster
contains an extra beta-like pseudogene, which apparently arose by a
small-scale duplication. The fixation of this duplication may indicate a
possible evolutionary role for pseudogenes.
相似文献
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Summary A novel nickel resistant, hyperaccumulatingN.crassa nir-2 mutant, isolated by us, sequestered 90% of Ni2+ from medium with 120 mg/l Ni2+. The parent wild strain showed comparable efficiency only at much lower concentrations (<10mg/l). The initial rapid rate and efficiency of Ni2+ removal could be maintained beyond 2 h by fresh addition of mycelial biomass. The results have been discussed from the stand point of the utility of metal resistant fungi in the control of environmental pollution. 相似文献
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