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911.
Sympathetic denervation of the iris muscle produces increases in both the breakdown of phosphatidylinositol 4,5-bisphosphate (PIP2) and in muscle contraction in response to norepinephrine (NE). To shed more light on the biochemical basis underlying this supersensitivity we investigated: the effects of NE on PIP2 breakdown, measured as myo-inositol trisphosphate (IP3) accumulation, and on muscle contraction in normal and denervated rabbit iris dilator; and the effects of denervation on selected biochemical properties of this muscle. The data obtained from these studies can be summarized as follows: The EC50 values (microM) for NE-induced IP3 accumulation in normal and denervated dilators were 14 and 3, respectively. This accumulation of IP3 was blocked by prazosin (1 microM). The EC50 values (microM) for NE-induced contraction for the normal and denervated muscles were 10 and 0.6, respectively. The NE-induced muscle contraction was blocked by prazosin (1 microM). The t1/2 values (s) for IP3 accumulation in normal and denervated muscles were 31 and 11, respectively, and for contraction the values were 19 and 9, respectively. Denervation increased significantly (15-18%) the basal labelling of phosphoinositides from myo-[3H]inositol, but not from 32P or [14C]arachidonic acid. Denervation had little effect on the activities of the enzymes involved in phosphoinositide metabolism. However, the activities of protein kinase C and Ca2+-ATPase increased in the denervated muscle. It is concluded that sympathetic denervation of the iris dilator renders the coupling between alpha1 receptors and PIP2 breakdown into IP3 and 1,2-diacylglycerol (DG) more efficient.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
912.
Mirza Rashid Ahmad 《Hydrobiologia》1967,29(3-4):388
Summary Controlled feeding experiments were carried out with Microcystis aeruginosa to study its effect on the fingerlings of Labeo rohita. The observation reveals an overall improvement in the general condition and a marked increase in weight, volume and size of fishes as compared to control. 相似文献
913.
Summary Effects of varying levels of nitrogenviz 40, 80 and 120 kg/ha and two methods of applicationviz (1) Soil application; and (2) one half applied to the soil and the other half to the plant foliage, were studied on growth and yield of wheat crop. Results showed that foliar feeding of urea in combination with soil application to wheat crop gave significant increases in their grain yields. Thus there is a great scope of utilizing this technique for increasing grain yields of wheat and other cereal crops grown in Iraq. 相似文献
914.
Summary Axenic shoot cultures ofCapsicum annuum cv.California Wonder were used as the source for isolation of protoplasts from mesophyll cells. Protoplasts underwent sustained mitotic activity and proliferated to form callus masses on NT or DPD medium enriched with 2,4-D, NAA and BAP each at 1 mg/l level. The callus could be differentiated into whole plants on the differentiation media and plants floweredin vitro under long day conditions. 相似文献
915.
Mokhtar Rania A. Saeed Rashid A. Alhumyani Hesham Khayyat Mashael Abdel-Khalek S. 《Cluster computing》2022,25(4):2541-2556
Cluster Computing - In cooperative mobile communications, spectrum sensing performance may encounter difficulties, which alert with many reporting errors, especially in dense network scenarios. In... 相似文献
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A. M. Rashid 《Animal genetics》1981,12(3):241-248
A comparison of ovotransferrin types A and B showed that in starch gel electrophoresis both types consisted of one major and one minor component. Both types have a similar amino acid composition as do the fragments from each type. Starch gel electrophoresis shows that the cause of the difference in the elec-trophoretic mobilities between ovotransferrin types A and B lies in the C-termi-nal half of the molecule. No physiological difference was found between types A and B, both types donate iron to chicken embryo red cells at equal rate. 相似文献
920.
Michal Hammel Ishtiaque Rashid Aleksandr Sverzhinsky Yasin Pourfarjam Miaw-Sheue Tsai Tom Ellenberger John M Pascal In-Kwon Kim John A Tainer Alan E Tomkinson 《Nucleic acids research》2021,49(1):306
The XRCC1–DNA ligase IIIα complex (XL) is critical for DNA single-strand break repair, a key target for PARP inhibitors in cancer cells deficient in homologous recombination. Here, we combined biophysical approaches to gain insights into the shape and conformational flexibility of the XL as well as XRCC1 and DNA ligase IIIα (LigIIIα) alone. Structurally-guided mutational analyses based on the crystal structure of the human BRCT–BRCT heterodimer identified the network of salt bridges that together with the N-terminal extension of the XRCC1 C-terminal BRCT domain constitute the XL molecular interface. Coupling size exclusion chromatography with small angle X-ray scattering and multiangle light scattering (SEC-SAXS–MALS), we determined that the XL is more compact than either XRCC1 or LigIIIα, both of which form transient homodimers and are highly disordered. The reduced disorder and flexibility allowed us to build models of XL particles visualized by negative stain electron microscopy that predict close spatial organization between the LigIIIα catalytic core and both BRCT domains of XRCC1. Together our results identify an atypical BRCT–BRCT interaction as the stable nucleating core of the XL that links the flexible nick sensing and catalytic domains of LigIIIα to other protein partners of the flexible XRCC1 scaffold. 相似文献