我国微茎类吸虫研究:ⅩⅢ.微茎类吸虫成虫结构特征排序

对我国52种微茎类吸虫的18项成虫形态学特征进行主成分分析,结果表明:卵巢位置、子宫延伸位置等7项性状对第一主成分贡献较大,提示描述器官位置的指标是重要的分类依据。52个虫种在前三个主成分上的排序图显示应将其划分成4个亚科。     

柱萤叶甲属研究（Ⅰ）鞘翅具黑色刻点的种类记述（鞘翅目：叶甲科）

本文就萤叶甲亚科中柱萤叶甲属鞘翅具黑色刻点的种类进行研究,共记述４种,我国已记录３种,其中１种为新种。     

我国微茎类吸虫的研究Ⅻ.类茎属及多黄属二新种报道：复殖目：微茎科

本文报道在湛江市附近海域海鸟体内获得的两种吸虫,经鉴定为新种,命名为巨口类茎吸虫,新种Ｍｉｃｒｏｐｈａｌｌｏｉｄｅｓ ｍａｃｒｏｓｔｏｎｒｓ ｓｐ．ｎｏｖ．,珊瑚多黄吸虫,新种Ｍｕｌｔｉｖｉｔｅｌｌｕｓ ｃｏｒａｌｉｕｓ ｓｐ．ｎｏｖ．     

Uridine transport in Novikoff rat hepatoma cells and other cell lines and its relationship to uridine phosphorylation and phosphorolysis.

Time courses of [³H]uridine uptake as a function of uridine concentration were determined at 25° in untreated and ATP-depleted wild-type and uridine kinase-deficient Novikoff cells and in mouse L and P388 cells, Chinese hamster ovary cells and human HeLa cells. Short term uptake was measured by a rapid sampling technique which allows sampling of cell suspensions in intervals as short as one and one-half seconds. The initial segments of the time courses were the same in untreated, wild-type cells in which uridine is rapidly phosphorylated and in cells in which uridine phosphorylation was prevented due to lack of ATP or uridine kinase. The initial rates of uptake, therefore, reflected the rate of uridine transport. Uridine uptake, however, was approximately linear for only five to ten seconds at uridine concentrations from 20–160 μM and somewhat longer at higher concentrations. In phosphorylating cells the rate of uridine uptake (at 80 μM) then decreased to about 20–30% of the initial rate and this rate was largely determined by the rate of phosphorylation rather than transport. At uridine concentrations below 1 μM, however, the rate of intracellular phosphorylation in Novikoff cells approached the transport rate. The apparent substrate saturation of phosphorylation suggests the presence of a low K_m uridine phosphorylation system in these cells. The “zero-trans” (zt) K_m for the facilitated transport of uridine as estimated from initial uptake rates fell between 50 and 240 μM for all cell lines examined. The zero-trans V_max values were also similar for all the lines (4–15 pmoles/μ1 cell H₂O.sec). The time courses of uridine uptake by CHO cells and the kinetic constants for transport were about the same whether the cells were propagated (and analyzed for uridine uptake) in suspension or monolayer culture. When Novikoff cells were preloaded with 10 μM uridine the apparent K_m and V_max values (infinite-trans) were two to three times higher than the corresponding zero-trans values. Uridine transport was inhibited in a simple competitive manner by several other ribo- and deoxyribonucleosides. All nucleosides seem to be transported by the same system, but with different efficiencies. Uridine transport was also inhibited by hypoxanthine, adenine, thymine, Persantin, papaverin, and o-nitrobenzylthioinosine, and by pretreatment of the cells with p-chloromercuri-benzoate, but not by high concentrations of cytosine, D-ribose or acronycin. The inhibition of uridine transport by Persantin involved changes in both V and K. Because of the rapidity of transport, some loss of intracellular uridine occurred when cells were rinsed in buffer solution to remove extracellular substrate, even at 0°. This loss was prevented by the presence of a transport inhibitor, Persantin, in the rinse fluid or by separating suspended cells from the medium by centrifugation through oil. Metabolic conversion of intracellular uridine were also found to continue during the rinse period. The extent of artifacts due to efflux and metabolism during rinsing increased with duration of the rinse.     

以化学纯饲料饲养北京的桃蚜

应用修改后的Dadd和Mitter(1966)全纯饲料配方配制成人工饲料饲养定居在北京温室烟草上的桃蚜 Myzus persicae可完成生活史井连续饲养3代。本文描述饲料配制、饲养和取食量测定的方法。这3代初羽化无翅孤雌胎生雌蚜的平均体重分别为:440±90.7μg,264±104.9μg和312±127.9μg。用放射性同位素稀释法测定取食量的结果得悉若虫期的总取食量每蚜约为1.74μg,相当于1.16μl。     

Facilitated transport of 6-mercaptopurine and 6-thioguanine and non-mediated permeation of 8-azaguanine in novikoff rat hepatoma cells and relationship to intracellular phosphoribosylation

6-Mercaptopurine and 6-thioguanine strongly inhibited the zero-trans entry of hypoxanthine into Novikoff rat hepatoma cells which lacked hypoxanthine/guanine phosphoribosyltransferase, whereas 8-azaguanine had no significant effect. 6-Mercaptopurine was transported by the hypoxanthine carrier with about the same efficiency as its natural substrates (Michaelis-Menten constant = 372 ± 23 μM; maximum velocity = 30 ± 0.7 pmol/μl cell H₂O per s). 8-Azaguanine entry into the cells, on the other hand, showed no sign of saturability and was not significantly affected by substrates of the hypoxanthine/guanine carrier. The rate of entry of 8-azaguanine at 10–100 μM amounted to only about 5% of that of hypoxanthine transport and was related to its lipid solubility in the same manner as observed for various substances whose permeation through the plasma membrane is believed to be non-mediated. Only the non-ionized form of 8-azaguanine (pK_a = 6.6) permeated the cell membrane.Studies with wild type Novikoff cells showed that permeation into the cell was the main rate-determining step in the conversion of extracellular 8-azaguanine to intracellular aza-GTP and its incorporation into nucleic acids. In contrast, 6-mercaptopurine was rapidly transported into cells and phosphoribosylated; the main rate-determining step in its incorporation into nucleic acids was the further conversion of 6-mercaptopurine riboside 5'-monophosphate.     

小麦倒春寒研究现状与进展

由于全球气候变暖,近年来小麦低温灾害事件频发,尤其是拔节-孕穗期的倒春寒灾害已成为制约小麦产量和品质的重要因素之一。本文综述了小麦倒春寒灾害的发生特点(鉴定与分级、时空特征),倒春寒对小麦生理特性(叶片、茎秆、穗部、根系)和产量、质量的影响,总结了抗倒春寒小麦育种、倒春寒危害的分子生物学机制及灾害的监测预警与风险评估等方面的研究进展,并从小麦抗倒春寒遗传基础、倒春寒危害小麦评价体系和防控技术体系等方面进行了展望,以期为抗倒春寒小麦品种的遗传改良和栽培调控新措施的建立提供理论依据。     

小麦族植物的分类现状及主要存在的问题

小麦族(Triticeae)是禾本科、早熟禾亚科中一个有重要经济价值、以多年生植物占优势的族,族内绝大多数种类是重要的粮食作物和畜牧业上的优良牧草,饲用价值极高,有些种类具有耐寒、耐旱、耐碱等特性,是农牧业上良种繁育、牧草利用的重要基因资源。但该族同时又是分类学上的一个疑难族,各学者对族内系统分类意见不一、争议颇大,尤其在族的界限、族下类群划分以及类群演化关系上问题较多,至今尚未解决。查阅了国内外分类学文献,探讨其分类差异以及存在问题,为充分开发利用中国丰富的小麦族植物资源提供理论依据。