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41.
A greenhouse assay to screen sunflower for resistance to Alternaria helianthi is described. A comparison of conditions led to the following standard conditions being recommended. The first or second pair of leaves of seedling plants at the V8 growth stage are inoculated using inoculum grown on sunflower leaf extract agar for 5–10 days at an inoculum density of 1–2 spores cm2 of leaf tissue. A 48 h dew period should be applied to plants covered by a plastic tent. A dew period temperature of 26/26°C night/day and a post-dew period temperature relative to that experienced under local growing conditions should be applied. Lesions are measured 7 days after inoculation, and mean lesion size per plant is calculated. Mean lesion size of lines being tested is expressed as a proportion of the mean lesion size of a susceptible standard included in each screening experiment. 相似文献
42.
43.
The primary humoral responses of mice to the linear random terpolymerl-Glu56-l-Lys35-l-Phe9 (GLø) were studied, utilizing the Farr antigen-binding technique and a new hemagglutination assay. This new hemagglutinin assay was easier and more convenient than the conventional Farr method, and was more sensitive in detecting early IgM responses. Following primary immunization, the majority of antibodies produced by responder strains were 2-ME-sensitive. These 2-ME-sensitive antibodies chromatographed at the same relative position as IgM on a Sepharose 6B column. On the other hand, no antibodies of either the IgM or IgG class could be detected in nonresponder strains. These data are consistent with the hypothesis that two complementingIr genes are required for the primary IgM response to GLø, in contrast to findings previously reported for (T,G)-A — L, anotherH-2-linked, complementing,Ir gene system. The implications of these differences are discussed. 相似文献
44.
本文分析30例慢性肺心病心衰并呼衰患者(心衰并呼衰组)及30例慢性肺心病心衰无呼衰患者(心衰无呼哀组)和慢性肺心病死亡组的血清甲状腺激素水平。结果表明心衰并呼衰组T_3、T_4水平均值显著低于心衰无呼衰组和健康组,心衰无呼衰组T_3水平均值显著低于健康组,肺心病死亡组T_3、T_4水平均值显著低于存活组,并发现血清T_3、T_4水平与动脉血氧分压(PaO_2)呈正相关。作者认为T_3明显降低是重症肺心病的损伤性结果,预示病情严重,预后差。而T_4明显下降,可能是死亡的信号之一。 相似文献
45.
The goal of this study was to characterize how isotonic contractions affect the rate of fatigue development. Muscle bundles dissected from frog sartorius muscles were stimulated with 100-ms long train of pulses (0.5 ms, 6 V, 140 Hz). To measure the effect of the isotonic contractions, isometric tetanus were elicited at regular time intervals during the stimulation to fatigue. In general, isotonic contractions caused a faster decrease in tetanic force than isometric contractions. The difference in tetanic force between an isotonic and isometric fatigue increased gradually over a 20-min period to 7.9 and 13.5% at 0.04 and 0.1 trains/s (TPS), respectively. At 0.2, 0.5, and 1.0 TPS, the decrease in tetanic force was also faster during an isotonic fatigue, which resulted in an initial difference in tetanic force between the two types of fatigue. The difference did not exceed 18.5% and did not persist throughout the stimulation period; i.e., the difference disappeared before the end of the fatigue stimulation. The half-relaxation time was prolonged during fatigue development, and the prolongation was greater during an isotonic fatigue, except at 0.04 TPS. The increases in the half-relaxation time at 0.2, 0.5, and 1.0 TPS were followed by a decrease, and the decreases were especially pronounced during an isotonic fatigue at 0.5 and 1.0 TPS. The results showed for the first time that isotonic contractions cause a faster rate of fatigue development in frog sartorius muscles, and this effect depends on the frequency of stimulation. 相似文献
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47.
Protein ubiquitination has been implicated in ATP-dependent protein turnover and in a number of biological processes in eukaryotic cells. The ubiquitination activating enzyme, E1, and ubiquitin carrier protein, E2, are two essential enzymes in the protein ubiquitination machinery. Using purified E1 and E2 from rabbit reticulocytes and various protein kinases, which include cAMP-dependent protein kinase, protein kinase C, and protein tyrosine kinase, we demonstrated that E1 is phosphorylated by protein kinase C, with a stoichiometry of 0.65 mol of phosphate/mol of E1, and one of the E2 isoforms, E2(32kDa), is phosphorylated by protein tyrosine kinase to 2 eq of phosphate/mol of protein. Phosphorylation of E1 causes a 2-fold enhancement of its activity as monitored by ubiquitin-dependent ATP in equilibrium PPi exchange. When 1 eq of phosphate was incorporated into E2(32kDa), a 2.4-fold activation was also observed for its activity to catalyze the ubiquitination of histone H2A. The regulatory significance of this finding is discussed. 相似文献
48.
Antigenic proteins of 36 and 29 kDa were localized in Spirometra mansoni plerocercoid (sparganum) immunohistochemically by avidin biotin complex (ABC) staining. When polyclonal antibodies such as BALB/c mouse serum immunized with crude saline extract of sparganum or confirmed sparganosis sera were reacted as primary antibodies, the positive chromogen (3-amino, 9-ethylcarbazole) reactions were recognized at syncytial tegument, tegumental cells, muscle and parenchymal cells and lining cells of excretory canals. A monoclonal antibody (MAb) which was reacting to 36 and 29 kDa proteins in the extract of the worm was localized at the syncytial tegument and tegumental cells. The present results suggested that the potent antigenic proteins of 36 and 29 kDa in sparganum were produced at the tegumental cells and transported to the syncytial tegument. 相似文献
49.
Sungho Kong David R. Yonge Donald L. Johnstone James N. Petersen Thomas M. Brouns 《Biotechnology letters》1992,14(6):521-524
Summary The distribution of chromium in subcellular components was examined with a fresh and starved denitrifying consortium by performing Cr+6 equilibration and cell fractionation tests. The cell wall fraction of 50 day starved cells adsorbed approximately 100% more chromium than did the cell wall fraction in fresh cells. The soluble fraction of 50 day old cells showed less affinity for chromium than fresh cells. 相似文献
50.
Proteins solubilized from the pharate cuticle of Manduca sexta were fractionated by ammonium sulfate precipitation and activated by the endogenous enzymes. The activated fraction readily converted exogenously supplied N-acetyldopamine (NADA) to N-acetylnorepinephrine (NANE). Either heat treatment (70 degrees C for 10 min) or addition of phenylthiourea (2.5 microM) caused total inhibition of the side chain hydroxylation. If chemically prepared NADA quinone was supplied instead of NADA to the enzyme solution containing phenylthiourea, it was converted to NANE. Presence of a quinone trap such as N-acetylcysteine in the NADA-cuticular enzyme reaction not only prevented the accumulation of NADA quinone, but also abolished NANE production. In such reaction mixtures, the formation of a new compound characterized as NADA-quinone-N-acetylcysteine adduct could be readily witnessed. These studies indicate that NADA quinone is an intermediate during the side chain hydroxylation of NADA by Manduca cuticular enzyme(s). Since such a conversion calls for the isomerization of NADA quinone to NADA quinone methide and subsequent hydration of NADA quinone methide, attempts were also made to trap the latter compound by performing the enzymatic reaction in methanol. These attempts resulted in the isolation of beta-methoxy NADA (NADA quinone methide methanol adduct) as an additional product. Similarly, when the N-beta-alanyldopamine (NBAD)-Manduca enzyme reaction was carried out in the presence of L-kynurenine, two diastereoisomers of NBAD quinone methide-kynurenine adduct (= papiliochrome IIa and IIb) could be isolated.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献