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821.
822.
Use of a new strategy to isolate and characterize 436 Drosophila cDNA clones corresponding to RNAs detected in adult heads but not in early embryos 总被引:13,自引:0,他引:13
M J Palazzolo D R Hyde K VijayRaghavan K Mecklenburg S Benzer E Meyerowitz 《Neuron》1989,3(4):527-539
We describe a new strategy for producing tissue-specific cDNA libraries and subsequently identifying tissue-specific clones. This method was used to screen for cDNA clones corresponding to RNAs expressed in the Drosophila head that cannot be detected in the early embryo. RNA blots were used to assess the spatial and temporal patterns of expression of these RNAs. The ensemble of 436 head-not-embryo clones identified roughly 700 distinct RNAs that are differentially expressed in the Drosophila head. The RNA expression patterns can be classified into five major categories. it is argued that this ensemble of clones represents a large fraction of all genes differentially expressed in the adult head, but not detected in the early embryo. Many of these genes are likely to encode eye- and nervous system-specific products. 相似文献
823.
The Clypeosphaeriaceae is retained to include sixteen genera.Apioclypea, Ceratostomella, Clypeophysalospora, Clypeosphaeria, Crassoascus, Jobellisia, Oxydothis andUrosporella are described and illustrated, whileApiorhynchostoma, Brunneiapiospora, Capsulospora, Duradens, Frondispora, Leiosphaerella, Pseudovalsaria andStereosphaeria are discussed. Genera in the Clypeosphaeriaceae are distinguished from those in, the Amphisphaeriaceae (sensu stricto). Their
ascomata are immersed and typically clypeate. Asci are 8-spored, unitunicate, cylindrical, with a J+ or J−, apical ring. Ascospores
are usually ellipsoidal or cylindrical, brown or hyaline, unicellular, pseudoseptase or septate, at times with appendages
or germ pores. The Clypeosphaeriaceae is considered a member of the Amphisphaeriales and the differences between the Clypeosphaeriaceae
and Amphisphaeriaceae are discussed. We are unsure if the Clypeosphaeriaceae as we define it is monophyletic. 相似文献
824.
The objective of this study was to test for the presence of transmural gradients of various components of the coronary microvasculature of the canine left ventricle. In order to achieve study objectives, the heart and coronary circulation were fixed in a reproducible state of myocardial and vascular tone (diastolic cardiac arrest and maximal coronary vasodilation). Morphometric methods which treat the coronary microvasculature as anisotropically arranged structures were applied for quantitative structural analysis. Eight dog hearts were fixed with a glutaraldehyde-cacodylate-buffered fixative by retrograde perfusion of the aorta with the heart in diastolic arrest and with maximal coronary vasodilation. Tissue samples were taken from areas near to the anterior and posterior papillary muscles from the subendocardium, subepicardium, and intermediate transmural locations. Morphometric results showed a homogeneously arranged array of microvascular and myocardial components with no significant differences in any of the primary morphometric measurements, down to the ultrastructural level, in myocytes relative to transmural location. The results suggest that transmural differences in coronary blood flow are not due to transmural structural differences but rather are due to physiological regulatory mechanisms of coronary blood flow. Further, the results indicate that failure to correct for anisotropy of myocardial structures can lead to erroneous conclusions concerning the structural basis of function in the heart. 相似文献
825.
Specificity studies of the binding of R1881 to crude placental homogenate gave surprising results in that certain steroids increased the binding of [3H]R1881 rather than displacing it. While data for 'competing', i.e. displacing, steroids were similar to those reported by other authors, there have been no previous reports of increased binding due to added steroids. This increased binding was due mainly to an increase in capacity (about 10-fold). These data suggest that the placental steroid-binding protein is unusual in that there is a second steroid-binding site whose occupancy increases the stability of the protein, thereby increasing its capacity to bind R1881. 相似文献
826.
This article describes two new anamorphic fungi from freshwater habitats, Dictyosporium tetrasporum sp. nov. and Exserticlava yunnanensis sp. nov., based on morphological characters. Both species are illustrated with light micrographs and compared with similar
taxa. Pseudofuscophialis lignicola and Pseudobotrytis terrestris are reported as new records from freshwater habitats. 相似文献
827.
Spin-label saturation-transfer electron spin resonance detection of transient association of rhodopsin in reconstituted membranes 总被引:2,自引:0,他引:2
Rotational diffusion of rhodopsin in reconstituted membranes of phosphatidylcholines of various alkyl chain lengths has been measured by using saturation-transfer electron spin resonance spectroscopy as a function of temperature and lipid/rhodopsin mole ratio. For dipalmitoyl-phosphatidylcholine, the rotational correlation time is 20 microseconds at physiological concentration, the same as in rod outer segment (ros) membranes. Dilution reduces the time to 10 microseconds, a value that is ascribed to well-dispersed monomeric rhodopsin. Use of phospholipids with longer or shorter chains results in sharply increased rotational correlation times. It is concluded that rhodopsin molecules are transiently associated in both reconstituted and ros membranes and that the nature of the association is determined by lipid type and composition. 相似文献
828.
Lung clearance of inhaled 99mTc-DTPA in the dog 总被引:2,自引:0,他引:2
829.
Accelerated proteolysis of tropoelastin and elastin occurs in the major arteries of chicks fed copper-deficient diets. Signs of elastin degradation are not obvious in normal arteries of copper-supplemented chicks. It is proposed that the sources of proteases that effect elastin degradation are from plasma and serum. Both calcium-dependent proteases and kallikrein were effective in degrading tropoelastin and partially crosslinked insoluble elastin into peptides similar to those detected in aortic extracts from copper-deficient chicks. As dietary copper deficiency progresses it is also possible to detect elastin peptides in plasma. 相似文献
830.