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121.
Brian Snoad 《Genetica》1966,37(1):247-254
By appropriate genetical studies using reciprocal translocation stocks it has been possible to confirmLamprecht's evidence that inPisum there are seven linkage groups.
Lamm's evidence for six linkage groups has been shown to be due to incomplete knowledge of the chromosomal structure of certain interchange lines.It is suggested thatLamprecht's system of chromosomal nomenclature should be universally adopted forPisum.Lamm &Miravelle's extended tester set has been accordingly renumbered and the intercrossing of the interchange lines completed in order to extend the confirmatory evidence as to their chromosomal constitution. 相似文献
122.
Twenty-two patients with chronic productive bronchitis or bronchiectasis were treated by direct instillations of normal saline and N-acetylcysteine into the trachea through a percutaneous catheter following a period of conventional routine therapy.The instillation, using either normal saline or varying concentrations of N-acetylcysteine did not produce significant change in alveolar gas exchange as reflected by measurement of arterial PaCO2 and the alveolar arterial gradient for oxygen during and after the introduction of the medication into the bronchial tree. Studies were carried out after patients had been stabilized breathing pure oxygen on an IPPB machine for 30 minutes.Evaluation of the treatment by means of pulmonary function tests demonstrated significant improvement in overall function following therapy.The results indicate that the technique of tracheobronchial lavage is physiologically benign and that overall improvement in pulmonary function can be obtained by this means in cases of the type described in this study. 相似文献
123.
Brian J. S. Harley 《CMAJ》1960,82(22):1123-1126
124.
125.
The CAT gene which codes for the enzyme chloramphenicol acetyltransferase was found to be ineffective as a reporter gene in cells and tissues of Brassica species. High levels of endogenous CAT activity were found to be widespread among this genus and did not appear to be distributed in a tissue- or cell-specific manner. Moreover, the presence of an inhibitor of CAT activity was discovered in Brassica napus and Brassica juncea. This inhibitor appeared to act selectively on bacterial CAT in transgenic plants. These findings provided an explanation for difficulties experienced in the detection of transgenic CAT activity in B. napus. 相似文献
126.
Social competition among gynes in halictine bees: The influence of bee size and pheromones on behavior 总被引:3,自引:0,他引:3
Solitary gynes of two species of social bees, Lasioglossum (Evylaeus) malachurumand L. (E.) pauxillum(Hymenoptera: Halictidae), were observed in the field and in the laboratory during the solitary (spring) phase of their life cycles. Fighting over nests among gynes of the former species is common when nests are being provisioned and can result in serious injury or even death to one or both interactants. The payoff is occasional acquisition of a nest. In contrast, fighting was never observed in the field among gynes of L. pauxillum.Several factors determine the outcome of such fights in L. malachuram,these include relative sizes of the two opponents as well as nest ownership. Dyadic interactions in the laboratory reveal that size influences the behavioral strategies of the gynes of both species, with the larger of two individuals in a dyadic interaction being on average more aggressive. Furthermore, in a second experimental series with L. malachurum,application to the smaller gyne of synthetically derived macrocyclic lactones found in the species' Dufour's gland pheromone mixture significantly decreased the aggressive tendencies of the larger such that its behavior was no longer significantly different from that for the smaller gyne. Therefore, among gynes, aggressive pheromonal signaling, coupled with other possible signal modalities, is probably an integral part in the communication system. 相似文献
127.
Cl− channels in basolateral renal medullary memnbranes: III. Determinants of single-channel activity
Christopher J. Winters W. Brian Reeves Thomas E. Andreoli 《The Journal of membrane biology》1990,118(3):269-278
Summary We evaluated the effects of vawrying aqueous Cl– concentrations, and of the arginyl- and lysyl-specific reagent phenylglyoxal (PGO), on the properties of Cl– channels fused from basolaterally enriched renal medullary vesicles into planar lipid bilayers. The major channel properties studied were the anion selectivity sequence, anionic requirements for, channel activity. and the efects of varying Cl– concentrations and/or PGO on the relation between holding voltageV
H
-mV) and open-time probability (P
o).Reducingcis Cl– concentrations, in the range 50–320mm, produced a linear reduction in fractional open time (P
v) with a half-maximal reduction inP
o atcis Cl–170mM. Channel activity was sustained by equimolar replacement ofcis Cl– with F–, but not with impermeant isethionate. Fortrans solutions, the relation between Cl– concentration andP
0 at 10mm Cl–. Reducingcis Cl– had no effect on the gating charge (Z) for channel opening, but altered significantly the voltage-independent, energy (G) for channel opening.Phenylglyoxal (PGO) reducedZ and altered G for Cl– channel activity when added tocis, but nottrans solutions, Furthermore, in the presence ofcis PGO, reducing thecis Cl– concentration had no effect onZ but altered G. Thus we propose thatcis PGO and,cis Cl– concentrations affect separate sites determining channel activity at the extracellular faces of, these Cl– channels. 相似文献
128.
Summary The present studies examined some of the properties of Cl– channels in renal outer medullary membrane vesicles incorporated into planar lipid bilayers. The predominant channel was anion selective having aP
Cl/P
K ratio of 10 and a unit conductance of 93 pS in symmetric 320mm KCl. In asymmetric KCl solutions, theI-V relations conformed to the Goldman-Hodgkin-Katz equation. Channel activity was voltage-dependent with a gating charge of unity. This voltage dependence of channel activity may account, at least in part, for the striking voltage dependence of the basolateral membrane Cl– conductance of isolated medullary thick ascending limb segments. The Cl– channels incorporated into the planar bilayers were asymmetrical: thetrans surface was sensitive to changes in ionized Ca2+ concentrations and insensitive to reducing KCl concentrations to 10mm, while thecis side was insensitive to changes in ionized Ca2+ concentrations, but was inactivated by reducing KCl concentrations to 50mm. 相似文献
129.
Summary A large amount of information is contained within the phylogentic relationships between species. In addition to their branching patterns it is also possible to examine other aspects of the biology of the species. The influence that deleterious selection might have is determined here. The likelihood of different phylogenies in the presence of selection is explored to determine the properties of such a likelihood surface. The calculation of likelihoods for a phylogeny in the presence and absence of selection, permits the application of a likelihood ratio test to search for selection. It is shown that even a single selected site can have a strong effect on the likelihood. The method is illustrated with an example fromDrosophila melanogaster and suggests that delerious selection may be acting on transposable elements. 相似文献
130.
Autoradiographic Localization of Angiotensin II Receptor Binding Sites on Noradrenergic Neurons of the Locus Coeruleus of the Rat 总被引:2,自引:2,他引:0
The locus coeruleus (LC) of the rat was lesioned by microinjection of selective neurotoxins into the brainstem. 6-Hydroxydopamine (6-OHDA), 3 micrograms/microliter, given unilaterally at two sites 0.6 mm apart on the rostro-caudal axis of the LC, was used to lesion catecholamine-containing neuronal elements. Ibotenic acid, 2.5 micrograms/0.5 microliters, administered similarly was used to lesion nerve cell bodies. Two weeks after administration of the neurotoxin, lesion efficacy was determined based on the norepinephrine content of the cerebral cortex ipsi- and contralateral to the lesion. 6-OHDA lesions of the LC caused a 46% reduction in ipsilateral cortical norepinephrine and a 60% reduction in specific 125I-[Sar1, Ile8]-angiotensin II (125I-SIAII) binding in the LC. Ibotenic acid lesions of the LC caused a 73% reduction in ipsilateral cortical norepinephrine and a 81% reduction in specific 125I-SIAII binding in the LC. These results indicate that AII receptor binding sites in the LC are localized on noradrenergic nerve cell bodies or their dendritic and axonal ramifications within the LC. 相似文献