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111.
Abstract— Two types of Ca2+ -dependent protein kinases were demonstrated and partially purified from the cytosol fraction of rat brain by DEAE-cellulose, Sephadex G-200, and calmodulin-affinity column chromatography, using endogenous proteins and chicken gizzard myosin light chains as substrates. The molecular weights of the enzymes were 88,000 (peak I) and 120,000 (peak II) on gel filtration. Peak I had no affinity for calmodulin, whereas peak II had a high affinity for it, with a K a value of 16.7 n m . The K a values of peaks I and II for Ca2+ were 2.4 and 1.6 μ m , respectively. 相似文献
112.
Tetsuhiro Sakai Toshitaka Ikehara Hiroshi Miyamoto Kenichi Kaniike 《Life sciences》1981,29(23):2429-2436
Growth of HeLa cells cultured with a chemically defined medium was slightly stimulated in the presence of 5% dialyzed calf serum. The growth-promoting action of serum was more conspicuous when cell growth was suppressed in the same medium, in which K+ was replaced by Rb+ to various ratios. The growth-promoting factors(s) of serum was heat-labile. Upon addition of dialyzed serum, passive K+ or Rb+ influx was increased, whereas the active cation uptake was unaffected and cell K+ was rather decreased. The serum did not alter uptake of [3H] amino acids. Also, protein synthesis inhibited in the Rb+-substituted medium was not stimulated significantly, except that observed only when the external K+/Rb+ ratio was . From the distinct effects of serum on cell growth and protein synthesis, we conclude that (i) the serum-induced stimulation of cell growth, which is suppressed in the Rb+-substituted medium, is not a result of the direct effect of serum on synthesis of bulk protein, but a reflection of the effect on another mechanism(s) required for cell growth; and that (ii) this action is basically identical with the growth-promoting action on cells cultured in the normal medium. 相似文献
113.
114.
NAD-linked glutamate dehydrogeanse [EC 1.4.1.2] was detected together with NADP-linked glutamate dehydrogenase [EC 1.4.1.4] and aspartase [EC 4.3.1.1] in Pseudomonas fluorescens cells. The three enzymes were distinctly separated by DEAE-Sephadex column chromatography. The NAD-linked enzyme was extremely thermolabile and was rapidly inactivated even at temperatures as low as 35--40 degrees C. The combined addition of NAD+ and glutamate, however, effectively stabilized the enzyme. The glutamate saturation profile of the NAD-linked enzyme exhibited cooperativity with a Hill coefficient (n) of 1.4. ATP inhibited the enzyme in an allosteric manner, increasing the n value to 2.2. These results suggest a novel type of metabolic regulation shared by the three enzymes in the biosynthesis and catabolism of amino acids. 相似文献
115.
Radioactively labeled vaccinia, cowpox and Shope fibroma virions free from any detectable contamination with host cell protein, were dissociated into their constituent polypeptides, and these were then analyzed by SDS-polyacrylamide gel electrophoresis and autoradiography. The profiles of constituent polypeptide bands of four strains of vaccinia virus (IHD-W, IHD-J, Lister and DIs) were almost the same, except that a polypeptide of about 41,000 daltons was not detectable in the autoradiogram of strain IHD-W which has no hemagglutinin. The profile of polypeptide bands of cowpox virions was also almost the same as that of vaccinia virions, except for several polypeptides of about 40,000 to 50,000 daltons, but the profile of Shope fibroma virions differed considerably from that of vaccinia or cowpox virions. 相似文献
116.
Halophilic Bdellovibrio, which is parasitic and lytic to Vibrio pharahaemolyticus, was ioslated from fresh sea water in the winter. It had a lethal effect on V. parahaemolyticus. The optimum temperature ofr multiplication ranged from 25 C to 30 C and growth was not observed at 35 C. Plaque numbers of the isolate reached a maximum in 17 hr under conditions of shaking at 25 C in autoclaved sea water supplemented with V. parahaemolyticus cells, and were as high as ten times the number of host cells. With respect to the host-suspended medium, the isolate multiplied in natural sea water ten times more than in Herbst's artificial sea water but did not grow in saline. V. parahaemolyticus, Vibrio alginolyticus and several species in the Vibrio genus were susceptible to the parasite on the basis of plaque formation but Escherichia coli and Staphylococcus aureus were not. 相似文献
117.
118.
Summary The changes in exchangeable sodium and total dissolved salts due to the application of sulfuric acid and water to sodium-affected
calcareous soils were studied for the purpose of establishing a convenient way of determining acid and leaching water requirements.
Conventional methods which ignore the effect of sodium removed from soil exchange sites are inadequate for estimating amounts
of acid needed to obtain a desired level of exchangeable sodium, especially at high acid application rates. Modified equations
are presented which predict the changes in exchangeable sodium and total dissolved salts using essentially the same input
data needed for conventional methods, and appear advantageous for estimating acid and leaching water needs.
Contribution from the Department of Soils, Water and Engineering, The University of Arizona, Tucson 82751, Arizona Agricultural
Experiment Station Journal No. 2340. Supported in part by a grant from the Arizona Mining Association. 相似文献
119.
Multiple cyclic nucleotide phosphodiesterase activities from rat tissues and occurrence of a calcium-plus-magnesium-ion-dependent phosphodiesterase and its protein activator.
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1. Supernatant fluids from rat cerebral cortex, cerebellum, kidney, heart and liver contained more phosphodiesterase activity hydrolysing cyclic GMP than that hydrolysing cyclic AMP when assayed with sub-saturating concentrations of substrate. 2. These activities were resolved into several fractions by Sephadex G-200 gel filtration; no two tissues had similar activity profiles. 3. With every tissue examined, a fraction (fraction II) with a molecular weight of about 150,000 was obtained which hydrolysed cyclic GMP preferentially at sub-saturating substrate concentrations in the presence of micromolar concentration of Ca2+, millimolar concentration of Mg2+ and a protein activator. 4. The activity of fraction II accounted for about 60 percent in liver, more than 80 percent in heart and cerebellum, and almost 100 percent in cerebral cortex of the total activity for cyclic GMP hydrolysis, calculated from the activity profiles. 5. Km values of fraction II samples from kidney, heart and liver for cyclic GMP were 1.3, 1.7 and 5 muM respectively. 6. 3-Isobutyl-1-methylxanthine inhibited hydrolysis of cyclic GMP by fraction II with an I50 value of 3muM for heart and liver and 50 muM for cerebrum. 7. The activator protein, with an estimated molecular weight of about 30,000 was isolated from all the tissues listed in 1.8. The concentrations of activator protein and of the isolated enzyme, fraction II, did not correspond exactly. 相似文献
120.
Hiroyuki Koga Haruka Fujitani Yoshiaki Morino Norio Miyamoto Jun Tsuchimoto Tomoko F. Shibata Masafumi Nozawa Shuji Shigenobu Atsushi Ogura Kazunori Tachibana Masato Kiyomoto Shonan Amemiya Hiroshi Wada 《PloS one》2016,11(2)
Over the course of evolution, the acquisition of novel structures has ultimately led to wide variation in morphology among extant multicellular organisms. Thus, the origins of genetic systems for new morphological structures are a subject of great interest in evolutionary biology. The larval skeleton is a novel structure acquired in some echinoderm lineages via the activation of the adult skeletogenic machinery. Previously, VEGF signaling was suggested to have played an important role in the acquisition of the larval skeleton. In the present study, we compared expression patterns of Alx genes among echinoderm classes to further explore the factors involved in the acquisition of a larval skeleton. We found that the alx1 gene, originally described as crucial for sea urchin skeletogenesis, may have also played an essential role in the evolution of the larval skeleton. Unlike those echinoderms that have a larval skeleton, we found that alx1 of starfish was barely expressed in early larvae that have no skeleton. When alx1 overexpression was induced via injection of alx1 mRNA into starfish eggs, the expression patterns of certain genes, including those possibly involved in skeletogenesis, were altered. This suggested that a portion of the skeletogenic program was induced solely by alx1. However, we observed no obvious external phenotype or skeleton. We concluded that alx1 was necessary but not sufficient for the acquisition of the larval skeleton, which, in fact, requires several genetic events. Based on these results, we discuss how the larval expression of alx1 contributed to the acquisition of the larval skeleton in the putative ancestral lineage of echinoderms. 相似文献