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21.
Craighton S. Mauk C. Richard Unrath Sylvia M. Blankenship 《Journal of Plant Growth Regulation》1990,9(1-4):181-184
A rapid, sensitive, and economical chemical analysis of the triazole, gibberellin-inhibitor, paclobutrazol (PP333, [(2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4 triazol-1-yl) pentan-3-ol]) was sought, featuring high-performance liquid chromatography (HPLC) as the final quantitation step. Three C18-reverse phase columns (conventional, 250×4.6 mm; cartridge type, 125×4.6 mm; and minicolumn, 33×4.6 mm) were evaluated for their performance in HPLC separation and quantitation of PP333 applied to soil and plant foliage. The 125-mm Whatman Partisil 5 ODS-3 cartridge column was superior to the standard 250-mm DuPont Zorbax ODS unit, and provided enhanced resolution and reduced solvent consumption, analysis time, and cost. A Perkin-Elmer Pecosphere 3×3C-C18 cartridge system was also superior to the 125-mm column with respect to these parameters. Although this minicolumn necessitated an additional purification step prior to HPLC analysis, its exceptionally fast analysis time and recovery period coupled with a high degree of sensitivity rendered it the most superior unit. This HPLC technology provided an efficient means of assaying for PP333 in large-scale experiments dealing with the chemical's absorption, translocation, and physiological response. 相似文献
22.
Uno Lindberg Clarence E. Schutt Eva Hellsten Ann-Christine Tjder Thomas Hult 《Biochimica et Biophysica Acta (BBA)/General Subjects》1988,967(3)
In the purification of proline hydroxylase by affinity chromatography on poly(L-proline)-Sepharose it was found earlier that two other components, profilin and the complex profilin-actin, also bind with high affinity to this matrix. We have exploited this observation to develop a rapid procedure for the isolation of profilin and profilin-actin complexes in high yields directly from high-speed supernatants of crude tissue-extracts. Through an extensive search for elution conditions, avoiding poly(L-proline) as the desorbant, we have found that active proteins can be recovered from the affinity column with a buffer containing 30% dimethyl sulphoxide. Subsequent chromatography on hydroxylapatite separates free profilin and the two isoforms of profilactin, profilin-actinβ and profilin-actinγ. The profilin-actin complexes produced this way have high specific activities in the DNAase-inhibition assay, give rise to filaments on addition of Mg2+, and can be crystallized. From the isolated profilin-actin complexes the β- and γ-actin isoforms of non-muscle cells can easily be prepared in a polymerization competent form. Pure profilin is either obtained from an excess pool present in some extracts or by dissociation of profilin-actin complexes and removal of the actin. 相似文献
23.
Activation of a low specific activity form of DNA polymerase alpha by inositol-1,4-bisphosphate 总被引:9,自引:0,他引:9
A low activity form of DNA polymerase alpha immunoaffinity-purified from adult-derived human fibroblasts was activated by interaction with phosphatidylinositol-4-monophosphate, while a high activity form of the enzyme did not interact with phosphatidylinositol-4-monophosphate or its derivatives. Phosphatidylinositol-4-monophosphate was apparently hydrolyzed in the presence of a highly purified low activity form of DNA polymerase alpha, effecting the release of diacylglycerol and the retention of inositol-1,4-bisphosphate by the enzyme complex. The resulting inositol-1,4-bisphosphate/protein complex exhibited increased affinity of binding to DNA template/primer and increased deoxynucleotidyltransferase activity. These data indicate that inositol-1,4-bisphosphate may function as an effector molecule in the activation of a low activity form of human DNA polymerase alpha and suggest that it may function as a second messenger during the initiation of mitosis in stimulated cells. 相似文献
24.
25.
Summary The production of -linolenic acid (GLA) by the fungus Mucor rouxii CBS 416.77 was studied on low budget nitrogen and carbon sources, i.e. rape meal, cocos expeller and two types of yeast extract (nitrogen sources), and starch, starch hydrolysate, beet molasses and cocos expeller (carbon sources). As references, Difco yeast extract and glucose were used. In flask cultivations the three yeast extracts were fully interchangeable, while the Difco yeast extract (the most expensive of those tested) gave a higher productivity of GLA in fermentor cultures (14 mg·l–1·h–1). The yield of lipids and GLA were increased in the order yeast extract < rape meal < cocos expeller. Thus the amount of lipid increased from 0.56 to 2.8 g·l–1, and that of GLA from 0.15 to 0.33 g·l–1. Use of beet molasses or cocos expeller as carbon sources gave poor growth. Starch and starch hydrolysate resulted in better productivity of GLA than glucose (4.7 and 4.9 compared to 3.4 mg·l–1·h–1).
Offsprint requests to: A.-M. Lindberg 相似文献
26.
Nurit Eyal Nurit Firon Sylvia Wilder Edwin H. Kolodny Mia Horowitz 《Human genetics》1991,87(3):328-332
Summary Single-stranded cDNA was prepared from RNA obtained from a patient with type 1 Gaucher disease. The cDNA was amplified in vitro and analyzed by sequencing. Three base-pair changes were identified which included a G to C transversion at nucleotide 3119 of the active gene (Asp140His), an A to C transversion at nucleotide 3170 (Lys157Gln) and a G to A change at nucleotide 5309 (Glu326Lys). To study the mode of inheritance of the three different base-pair changes, genomic DNA was prepared from blood or skin fibroblasts of several family members. Genomic glucocerebrosidase DNA sequences were amplified and subjected to hybridization with allele-specific oligonucleotides (ASOs). The hybridization profiles demonstrated that two of the basepair changes originated from the mother and were transmitted to her two affected sons and to a grandchild, while the third base-pair change, originating from the father, was transmitted to his two affected sons, a carrier daughter and a second grandchild. Tests of other patients with Gaucher disease failed to disclose the presence of the three base-changes. This is a unique family with three base-pair changes tightly linked to Gaucher disease. 相似文献
27.
A female racing greyhound dog was presented to the clinic at the age of 3 months with a 2 months’ history of irregular hindleg movements and thin hindleg muscles. On examination 1 month later, a squatting standing posture, a week proprio-ceptive positioning reaction, and severe atrophy and pain of the lumbar and thigh muscles, were evident. The dog was sacrificed and necropsied. The adrenals, hindleg muscles, kidneys, myo-cardium, peripheral nerves, spinal cord, thyroid, and tonsils were fixed in 10 % neutral buffered formalin and processed for histo-pathology. 相似文献
28.
Steady state kinetics were used to examine the influence of Cd2+ both on K+ stimulation of a membrane-bound ATPase from sugar beet roots (Beta vulgaris L. cv. Monohill) and on K+(86Rb+) uptake in intact or excised beet roots. The in vitro effect of Cd2+ was studied both on a 12000–25000 g root fraction of the (Na++K++Mg2+)ATPase and on the ATPase when further purified by an aqueous polymer two-phase system. The observed data can be summarized as follows: 1) Cd2+ at high concentrations (>100 μM) inhibits the MgATPase activity in a competitive way, probably by forming a complex with ATP. 2) Cd2+ at concentrations <100 μM inhibits the specific K+ activation at both high and low affinity sites for K+. The inhibition pattern appears to be the same in the two ATPase preparations of different purity. In the presence of the substrate MgATP, and at K+ <5 mM, the inhibition by Cd2+ with respect to K+ is uncompetitive. In the presence of MgATP and K+ >10 μM, the inhibition by Cd2+ is competitive. 3) At the low concentrations of K+, Cd2+ also inhibits the 2,4-dinitrophenol(DNP)-sensitive (metabolic) K+(86Rb+) uptake uncompetitively both in excised roots and in roots of intact plants. 4) The DNP-insensitive (non metabolic) K+(86Rb+) uptake is little influenced by Cd2+. As Cd2+ inhibits the metabolic uptake of K+(86Rb+) and the K+ activation of the ATPase in the same way at low concentrations of K+, the same binding site is probably involved. Therefore, under field conditions, when the concentration of K+ is low, the presence of Cd2+ could be disadvantageous. 相似文献
29.
Summary 1-Methylguanine and 7-methylguanine, both metabolic products of tRNA degradation, are known to induce transformation of Chinese hamster fibroblasts in culture. The effects of these compounds on the cell membrane have been studied by the method of Concanavalin A-mediated hemadsorption. 1-Methylguanine or 7-methylguanine induced a 50% increase of Con A-mediated hemadsorption within 20 hours of exposure of the cells to the agent at a concentration of 10-5 M. This alteration was reversed within 13 days when the cells were grown in the control medium. Prolonged treatment with 1-methylguanine or 7-methylguanine resulted in changes which were only slowly reversed during growth of the cells in the control medium. The effect of the methylated purines on the cell membrane could be completely inhibited by simultaneous addition of dibutyryl-cAMP at a concentration of 10-5 M. The possible mechanism of cell membrane alteration by methylated purines and its relevance to transformation in vitro are discussed. 相似文献
30.
The performance of The Subhuman Primate Pregnancy Test Kit was evaluated for routine detection of early (days 19-21) pregnancy in the rhesus monkey. Out of 123 confirmed matings, 19 resulted in pregnancy. In the pregnant animals the kit had an accuracy of 73.7%. In the nonpregnant females the accuracy was higher, 88.5%. False positives were encountered in ovariectomized females as well as adult intact males. 相似文献