Rotational streaming in fiber cells and its role in translocation

All visible protoplasmic streaming in sections of various plant stems was reversibly stopped by 2,4-dinitrophenol (DNP). Sections contained epidermal, cortical, and fiber cell types. Cells treated with DNP retained their semipermeability as evidenced by their plasmolysis in sucrose solutions. Washing out the DNP resulted in the rapid resumption of protoplasmic streaming in all 3 cell types. Both the rate of movement of sodium fluorescein and the shape of the advancing dye front were greatly altered by DNP treatment. Dye transport was decreased in the fibers and little affected in cortical cells. The results suggest that rotational streaming accelerates the translocation of soluble substances in fiber cells.     

复方人参茎叶皂甙对大鼠毛形态的影响

毛是哺乳动物所特有的组织,曾有报道,随个体年龄增长或某些疾病及药物会引起哺乳动物毛表面的毛小皮鳞片发生一系列的变化。(fujita et al.,1971)。所以毛形的变化可用于检测或筛选某些药物的疗效,其明显优点是取材对机体无损伤,且简单易行,又便于重复实验。 本实验用Wistar种雄性大鼠,饲以中药复方人参茎叶皂甙(简称8401,由沈阳中医研究所药理室处方设计,本溪市中药制药厂制备),观察其对毛形变化的影响,并与饲以人参根皂甙大鼠毛对比,以观     

微管的冷稳定性与植物抗寒性关系的研究

利用间接免疫荧光的细胞化学技术对番茄、黄瓜、菠菜、甜菜及小麦等不同抗寒性植物微管的冷稳性进行了比较研究。结果指出,不抗寒的喜温性植物番茄和黄瓜的气孔保卫细胞的微管在0℃—1℃冷处理3小时即解聚;属于中等抗寒性植物的菠菜和甜菜幼苗经秋季低温锻炼后,其气孔保卫细胞的微管在0℃和—5℃低温处理3小时,均不发生解聚;具有较强抗寒性的冬小麦品种农大139幼苗在2—3℃低温锻炼期间,微管结构保持完整,经过15天低温锻炼的幼苗在-8℃冰冻处理3小时,微管也不受破坏。这些结果表明,微管的冷稳性与植物的抗寒性成正相关。     

Characteristics of a membrane-associated lipoxygenase in tomato fruit

Microsomal membranes isolated from the pericarp of maturegreen tomato (Lycopersicon esculentum) fruit rapidly metabolize exogenous radiolabeled linoleic acid into fatty acid oxidation products at 22°C. The reaction is strongly inhibited by n-propyl gallate, an inhibitor of lipoxygenase. The membranes also rapidly metabolize 16:0/18:2^* phosphatidylcholine into radiolabeled oxidation products that comigrate on TLC plates with those formed from free linoleic acid. At 30°C, the formation of fatty acid oxidation products from 16:0/18:2^* phosphatidylcholine is slower, and there is an initial accumulation of radiolabeled linoleic acid that is not evident at 22°C, which can be attributed to the action of lipolytic acyl hydrolase. Radiolabeled phosphatidic acid and diacylglycerol are also formed during metabolism of 16:0/18:2^* phosphatidylcholine by the microsomal membranes, and there is no breakdown of either linoleic acid or phosphatidylcholine by heat-denatured membranes. When Triton X-100 treated membranes were used, the same patterns of metabolite formation from radiolabeled linoleic acid and 16:0/18:2^* phosphatidylcholine were observed. Thus, the enzymes mediating the breakdown of these radiolabeled compounds appear to be tightly associated with the membranes. Collectively, the data indicate that there is a lipoxygenase associated with microsomal membranes from tomato fruit that utilizes free fatty acid substrate released from phospholipids. The microsomal lipoxygenase is strongly active over a pH range of 4.5 to 8.0, comprises approximately 38% of the total (microsomal plus soluble) lipoxygenase activity in the tissue, has an apparent K_m of 0.52 millimolar and an apparent V_max of 0.186 millimoles per minute per milligram of protein. The membranous enzyme also cross-reacts with polyclonal antibodies raised against soybean lipoxygenase-1 and has an apparent molecular mass of 100 kilodaltons.     

Factors affecting superovulation in heifers treated with PMSG

In this study we determined 1) if the immunoneutralization of PMSG affected the ovulatory response, the number of large follicles and embryo yield compared with that of PMSG alone or pFSH, and 2) whether the stage of the estrous cycle at which PMSG was injected affected the ovulatory response and yield of embryos in superovulated heifers. Estrus was synchronized in 99 (Experiment 1) and 71 (Experiment 2) heifers using prostaglandin F2alpha (PG) analogue, cloprostenol, given 11 d apart in replicate experiments over 2 yr. In Experiments 1 and 2, heifers were randomly allocated to 1 of 3 treatments (initiated at mid-cycle): Treatment 1--24 mg of pFSH (Folltropin) given twice daily for 4 d; Treatment 2--a single injection of 2000 IU PMSG; Treatment 3--2000 IU PMSG followed by 2000 IU of Neutra-PMSG at the time of first insemination. In Experiment 3, 116 heifers were given 2000 IU PMSG on Day 2 (n = 28), Day 3 (n = 27), Day 10 (n = 41) or Day 16 (n = 20) of the estrous cycle. The PG was given at 48 h (500 microg cloprostenol) and 60 h (250 microg cloprostenol) after the first gonadotropin treatment. Heifers were inseminated twice during estrus, and embryos were recovered on Day 7, following slaughter and graded for quality. The numbers of ovulations and large follicles (> or =10 mm) were also counted. There was no effect of treatment on ovulation rate in Experiment 1, but in Experiment 2 it was greater (P < 0.002) in heifers given PMSG (14.7 +/- 1.5) than pFSH (7.5 +/- 1.4) or PMSG-neutra-PMSG (8.7 +/- 1.5). The number of large follicles was higher following PMSG than pFSH treatment in Experiment 1, and it was higher (P < 0.004) in heifers given PMSG (5.5 +/- 0.8) than pFSH (1.12 +/- 0.7) or PMSG-neutra-PMSG (2.7 +/- 0.8) in Experiment 2. The use of Neutra-PMSG did not affect the numbers of embryos recovered or numbers of Grade 1 or 2 embryos, but it did decrease the number of Grade 3 embryos in both experiments. In Experiment 3, the ovulation rate decreased (P < 0.004) when PMSG was given on Day 3 (5.7 +/- 1.46) of the cycle rather than on Day 2 (12.3 +/- 1.64), Day 10 (13.4 +/- 1.45) or Day 16 (12.5 +/- 1.87). There was no effect of day of treatment on the numbers of large follicles. The mean numbers of embryos recovered were lower (P < 0.01) in heifers treated on Day 3 (2.1 +/- 0.67) than on Day 2 (6.8 +/- 1.0), Day 10 (6.4 +/- 0.86) or Day 16 (7.8 +/- 1.87). It is concluded that Neutra-PMSG given to heifers treated with PMSG did not improve embryo yield or quality and that treatment with PMSG early in the cycle can result in acceptable embryo yields provided sufficient time elapses between treatment and luteolysis.     

锈寄生菌对落叶松褐锈病的抑制效应

目测及镜检结果表明,褐锈菌被锈寄生菌寄生后,夏孢子堆由桔红渐变为灰褐,后期夏孢子失去发芽力,孢子堆原基处只存有寄生菌的分生孢子器．锈寄生菌的发酵液代谢产物含有３种抗性物质．自７月中下旬至９月中旬,分生孢子的发生量多于褐锈菌的孢子量,表明落叶松褐锈病的发生程度随着锈寄生菌寄生率的增加而减轻．     

PKC,PKA和TPK在血小板激活中的作用

利用＾３２Ｐ－ＮａＨ２ＰＯ４标记猪血小板,然后,以ＰＭＡ,凝血酶,ＰＧＥ１腺苷等处理,结果表明,随着ＰＭＡ激活ＰＫＣ,血小板发生聚集,３５μｍｏｌ／ＬＰＧＥ１或１ｍｍｏｌ／ＬｄｂｃＡＭＰ不能抑制５０ｎｍｏｌ／ＬＰＭＡ诱导的血小板聚集,腺苷却能抑制ＰＭＡ诱导的血小板聚集（ＥＣ５０＝０．１ｍｍｏｌ／Ｌ,ｄｂ－ｃＡＭＰ,腺苷都不能抑制１００ｎｍｏｌ／ＬＰＭＡ诱导的４０ｋＤ蛋白磷酸化,ＰＫＡ激活不能抑制Ｐ