Reproductive regulation in the female Japanese minnow, Pseudorasbora parva (Cyprinidae)

The Japanese minnow, Pseudorasbora parva, is a multiple spawner that lays eggs repeatedly during the spawning season. In laboratory aquaria, 19 of 63 females did not spawn, whereas 44 other females laid 167 to 6285 eggs in 1 to 14 mating sequences. Neither fish density nor sex ratio (number of males per female) affected fecundity, but the increase in fish density significantly decreased the growth rate of females. The increase in male length significantly increased fecundity in aquaria which contained only a single male, whereas it decreased female growth rate. These relationships were not evident in aquaria housing three or ten males. Since larger males were more dominant and had larger testes than smaller males, the correlation between fecundity and male size strongly suggests that individual females regulated fecundity to increase their reproductive success.     

Some quantitative aspects of the disc electrophoresis of ovalbumin using amido black 10B stain

The quantitative aspects of the disc electrophoretic technique were investigated using a purified protein, egg ovalbumin. Depending on the filter used, a linear relationship between peak area and protein concentration was found up to about 40 μg of protein by densitometry. Both diffusion and gel slicing studies indicated that linearity could be extended to almost 160 μg of protein. By elution of the amido black dye from the protein-dye complex in the gel, a nearly constant dye to protein ratio was indicated. These results suggested that quantitation of the stained bands on polyacrylamide gels was limited by the nonlinear response of the densitometer, perhaps due to the nonlinearity of dye absorbance at large optical densities and not by variable amounts of dye binding to the protein bands.     

Analytical techniques for cell fractions. XIX. The cyclum: an automatic system for cyclic chromatography.

An automatic system, termed a Cyclum, is described which allows column chromatographic separations to be repeated precisely a large number of times. Provision is made for the adjustment during operation of parameters such as equilibration, wash, elution, and sample flow times and duration of fraction collection. The system is applicable to both analytical and preparative use in various types of column chromatography (e.g., affinity, gel filtration, ion-exchange), but has been especially developed for separations based on immunosorption.     

Visualization of cAMP receptor protein-induced DNA kinking by electron microscopy

The effect of specific DNA binding of the cAMP . cAMP receptor protein complex to two DNA fragments (301 and 2685 base-pairs in length) containing the lac operon has been investigated by electron microscopy. It is shown that specific DNA binding of the cAMP . cAMP receptor protein complex induces a kink of 30 to 45 degrees in the DNA with the apex of the kink located at the site of protein attachment. These findings lend direct visual support for the kinking hypothesis based on the observation of anomalous electrophoretic mobility of DNA fragments containing specifically bound cAMP receptor protein.     

The absorbance spectrum of the brown holo-membrane and the comparison of pI values of bacteriorhodopsin solubilized from purple membrane and from brown holo-membrane

Brown holo-membrane was prepared by the addition of all-trans-retinal to brown apo-membrane which was isolated from Halobacterium halobium grown in the presence of nicotine. The effects of pH and NaCI concentration on the absorbance spectrum of the brown holo-membrane were investigated in comparison with those of the purple membrane. The λ_max of the dark-adapted brown holo-membrane shifted from 560 to 600 nm by lowering pH. The pK value which was determined as the mid-point pH for the spectral red-shift was 5.8 in the absence of NaCl. It was lowered to 4.5 and 3.4 in 0.1 and 1 M NaCl solutions, respectively. The pK value for the brown holo-membrane was larger than the corresponding value for the purple membrane in the NaCl solution. Bacteriorhodopsins present in the purple membrane and in the brown holo-membrane were solubilized in the nonionic detergent, lauryl ester of sucrose. For both solubilized bacteriorhodopsins, the pK value of spectral red-shift was about 3.1 in water, and the pI value, determined by chromatofocusing, was about 4.6 at 22°C.     

免疫细胞疗法产业发展态势和发展建议

免疫疗法已被成功应用于多种肿瘤的治疗,显著提高患者的生存质量。免疫细胞疗法是当前免疫疗法研发的重点方向之一。免疫细胞疗法发展历经了由非特异性免疫到无差别化特异性免疫,再到差别化特异性免疫的发展阶段。免疫细胞疗法已有多个产品获批上市,产业体系初步成型,主要包括疗法/药物研发和相关服务/器材供应。通过梳理国内外免疫细胞疗法产业发展态势,分析免疫细胞疗法发展的技术瓶颈,找出我国发展该产业存在的主要问题,并提出发展建议,为我国发展免疫细胞疗法产业提供参考。     

深圳马峦山地区百合科和兰科植物资源及其在生态环境构建中的意义

百合科、兰科植物是重要的资源植物,在系统演化、物种多样性研究等方面均有重要意义。本文对马峦山地区百合科、兰科植物的种类、数量、生存状况、区域分布等进行调查,共收集百合科植物9属14种,分别占深圳市该科属种总数的64.3%和70.0%;兰科植物22属28种,分别占深圳市该科属种总数的68.8%和54.9%。在此基础上,对深圳中轴线地区自西至东依次出现的凤凰山森林公园(百合科3属3种;兰科4属4种)、铁岗森林公园(百合科3属3种;兰科4属4种)、塘朗山森林公园(百合科5属5种;兰科8属9种)、梧桐山风景区(百合科8属12种;兰科17属30种)、排牙山自然保护区(百合科7属8种;兰科26属35种)、七娘山地质公园(百合科9属10种;兰科21属30种)等的百合科、兰科植物进行比较研究,结合生态环境的梯度变化,说明其在生态环境、森林植被构建中的指示意义,并提出了对百合科、兰科植物加强保护、管理和研究的措施。     

广州市固体废物管理与处置现状及对策

分析广州市工业固体废物、危险废物、生活垃圾、余泥渣土等管理与处置现状,揭示广州市现有固体废物管理处置存在的主要问题,并提出对策建议。分析表明,近年广州市工业固体废物年产生量呈上升趋势,工业固体废物排放量有所回升;1999年危险废物实现零排放,医疗垃圾的集中处置率达100%;居民生活垃圾清运处置率达100%。生活垃圾分类收集率为26%,加快了垃圾填埋场的改造和建设;余泥渣土的管理逐步规范化,市区余泥渣土排放工地申领排放证率保持100%。存在问题包括管理上欠长远规划、处置技术落后、二次污染、资源回收率低、资金匮乏等,尤其缺乏对危险废物、废旧电池的集中处置机构。     

Bioecological fundamentals of phytosanitary situation management system in agroecosystems*

The principles of construction of a system of phytosanitary situation management in agroecosystems are discussed. The necessity of construction of management models based on record‐keeping of the objective laws of an ecology is underlined. The realization of control systems is carried out by means of development the economic threshold of harmfulness, ecological and economic thresholds of expediency of plant protection products application, ecotoxicological evaluation of pesticides application.     

The mitogenic effect of A23187 in human peripheral lymphocytes

The mitogenic action of the divalent ionophore A23187 was confirmed and shown to be very sensitive to changes in extracellular calcium ion concentration. At optimal calcium and ionophore concentrations, an increase in [³H]-thymidine incorporation was seen that was similar to that seen after phytohemagglutinin addition. A calcium-dependent stimulation of α-aminoisobutyric acid transport was also seen after A23187 addition.Studies with three inhibitors demonstrate a similarity between proliferation induced by phytohemagglutinin and by A23187. Isoproterenol (10^?4 M) and ouabain (10^?7 M) blocked the effects of phytohemagglutinin and A23187. A drug, D-600, that has been shown to block calcium channels in cardiac muscle, inhibited proliferation induced by either phytohemagglutinin or A23187. This concentration of D600 had no effect on either phytohemagglutinin- or A23187-induced ⁴⁵Ca²⁺ uptake. Furthermore, the (+) and (?) isomers separated from racemic D600, which have been shown to block sodium and calcium channels respectively in smooth muscle, had equal potency in blocking lymphocyte proliferation.