植物血细胞凝集素对小鼠脾脏淋巴细胞γ－谷氨酰基转肽酶活性的影响

本文就植物血细胞凝集素（ＰＨＡ）作用的不同时间对小鼠脾脏淋巴细胞γ－谷氨酰基转肽酶（γ－ＧＴ）活性的影响进行了观察。结果表明,脾脏淋巴细胞转化率随给予ＰＨＡ时间的延长而上升,对照组＜２４ｈ组＜４８ｈ组＜７２ｈ组;淋巴细胞γ－ＧＴ活性于２４ｈ明显强于对照组（Ｐ＜０．００１）,随着ＰＨＡ作用时间的延长其γ－ＧＴ活性逐渐下降,即４８ｈ组与对照组已无显著差异,而７２ｈ组却低于对照组（Ｐ＜０．００１）。可见ＰＨＡ在小鼠体内对γ－ＧＴ活性有很大影响。     

Deletion between direct repeats in T7 DNA stimulated by double-strand breaks.

An in vitro system based on extracts of Escherichia coli infected with bacteriophage T7 was used to study genetic deletions between directly repeated sequences. The frequency of deletion was highest under conditions in which the DNA was actively replicating. Deletion frequency increased markedly with the length of the direct repeat both in vitro and in vivo. When a T7 gene was interrupted by 93 bp of nonsense sequence flanked by 20-bp direct repeats, the region between the repeats was deleted in about 1 out of every 1,600 genomes during each round of replication. Very similar values were found for deletion frequency in vivo and in vitro. The deletion frequency was essentially unaffected by a recA mutation in the host. When a double-strand break was placed between the repeats, repair of this strand break was often accompanied by the deletion of the DNA between the direct repeats, suggesting that break rejoining could contribute to deletion during in vitro DNA replication.     

聚焦色谱法测定肌型肌酸激酶亚型

报道了测定CK-MM亚型的聚焦色谱法,此法简单,快速,结果可靠,线性范围宽,最低检测限（8U／L）较正常参考值低,比国外报道的类似方法高6倍以上,分离度亦有改进.测定了20例健康人血清亚型分布,与文献报道结果相近.该法自动化程度高,已在急性心梗的诊断中实际应用.     

急性脑出血综合治疗的几个问题探讨：附死亡80例分析

通过对８０例急性脑出血死亡组分析,发现死于脑疝的占６２．５％,脑疝与一种或二种以上合并症同存者占７７．５％,显著高于存活组（Ｐ＜０．０１）．它们互为因果,加速死亡。因此,应重视早期或超早期采用简易定向锥颅脑内血肿碎吸术吸除血肿,同时注意维持生命体征稳定,加强脱水降颅压,预防、控制合并症等综合治疗。且要全面分析,相互兼顾,正确处置。这是帮助机体渡过调控障碍难关,挽救生命的有效治疗措施。     

别藻蓝蛋白藻蓝胆素发色团分子构象研究

主要研究了蓝绿藻污棕席藻(Phormidium luridum)别藻蓝蛋白在不同 pH值条件下的吸收光谱和共振拉曼光谱.发现低聚化的结果导致了三聚体别藻蓝蛋白 650nm 特征吸收峰的消失和一些共振拉曼带强度和位置的移动.结果表明在低 pH 值作用下的低聚化的别藻蓝蛋白中藻蓝胆素发色团分子的构象和自由胆素分子类似,比三聚体的别藻蓝蛋白的发色团分子更趋于卷曲,折叠的构象态.而三聚体的别藻蓝蛋白,主要的拉曼带 1645cm^-1是其发色团分子构象处于更线性延展的标志,其光谱行为和吸收光谱 A_vis/A_uv所表征的发色团分子构象的结果相一致.     

A greenhouse assay to screen sunflower for resistance to Alternaria helianthi

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.     

Genetic control of the primary humoral response to Glu56Lys35Phe9

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.     

The effects of isotonic contractions on the rate of fatigue development and the resting membrane potential in the sartorius muscle of the frog, Rana pipiens.

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.     

Protein ubiquitination is regulated by phosphorylation. An in vitro study.

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.