Myoglobin diffusion in bovine heart muscle

The rotational mobility of myoglobin in situ was determined by proton nuclear magnetic resonance line width measurements of a characteristic myoglobin resonance observed in bovine heart muscle spectra. The protein diffuses intracellularly at nearly half the rate observed in dilute solution. This high mobility allows the oxygenated form of myoglobin to contribute significantly to the overall diffusive flux of oxygen in respiring heart muscle.     

海洋污损生物藤壶的附着机理及防除

藤壶是东海区主要的污损生物之一。阐述了藤壶污损海上设施的危害，并从藤壶的生物结构、生活环境等方面分析了藤壶的粘附机理，以及影响藤壶附着的多种因素，并介绍了有关防止藤壶污损的环保型挂海试验效果。     

Stearic acid as plasma replacement for intracellular in vitro culture of Plasmodium knowlesi

A chloroform extract of Cohn's fraction IV-4 of human plasma successfully replaced whole fraction IV-4 for the intracellular in vitro culture of Plasmodium knowlesi. We are now able to report the successful replacement of monkey plasma by stearic acid.     

藤壶金星幼虫附着变态机制

藤壶属节肢动物门(Arthropoda)甲壳亚门(Crustacea)蔓足下纲(Cirripedia)围胸总目(Thoracica), 具备特殊的形态结构、生活史和种群生态特征,是最主要的海洋污损生物。其幼虫阶段通常经历6期无节幼体和1期不摄食的金星幼虫,从浮游的金星幼虫附着变态成固着的稚体是藤壶生活史中的一个关键环节。外界化学和生物因子中成体提取物、水溶性信息素、足迹、神经递质、激素、生物膜等均影响藤壶金星幼虫的附着变态;内在因子即金星幼虫的生理状态(能量储量和年龄)决定了其对外界因子的反应程度。概括了近年来藤壶附着变态生理机制和分子机制研究的进展,可为深入了解藤壶金星幼虫附着变态机制提供参考,也为开发新型、高效、环保的防污剂提供理论指导。     

Fish in offshore kelp forests affect recruitment to intertidal barnacle populations

Kelp forests along the coast of central California harbor juvenile rockfish that prey on the larvae of invertebrates from the rocky intertidal zone. This predation reduces recruitment to barnacle populations to 1/50 of the level in the absence of fish. The dynamics of the intertidal community are thus strongly coupled to the dynamics of the offshore kelp community.     

Temporal summation and refractoriness in hypothalamic reward neurons as measured by self-stimulation behavior

A neurophysiological technique of double-pulse stimulation has been applied to freely moving rats with chronic indwelling electrodes in the hypothalamic reward area. Self-stimulation thresholds, measured as a function of the interpulse interval, generated curves with time constants characteristic of refractory periods and temporal synaptic summation. The results indicate a way of studying central neuronal processes for which the overt behavior of the animal is the dependent variable.     

Current-voltage relations during illumination: photoreceptor membrane of a barnacle

In voltage clamped photoreceptor cells of the barnacle, light-induced membrane current varied nonlinearly with membrane potential and changed sign at about + 27 millivolts (reversal potential) independently of light intensity. Instantaneous current-voltage relations were linear and intersected the voltage axis at the reversal potential. Illumination increased membrane conductance that was dependent on membrane potential, light intensity, and time.     

The permeability of plant cell walls as measured by gel filtration chromatography

The permeability of plant cell walls to macromolecules may limit the ability of enzymes to alter the biochemical and physical properties of the wall. Proteins of molecular weight up to 60,000 can permeate a substantial portion of the cell wall. Measurements of wall permeability in which cells are exposed to hypertonic solutions of macromolecules may seriously underestimate wall permeability.     

Photoreception in a barnacle: electrophysiology of the shadow reflex pathway in Balanus cariosus

The photoreceptors in the median ocellus of the rock barnacle depolarize when illuminated. This depolarization spreads passively to the axon terminals in the supraesophageal ganglion. A small number of cells in the supraesophageal ganglion hyperpolarize when the median ocellus is illuminated and depolarize when it is shadowed. Nerve impulses are superimposed on the slow depolarization of the ganglion cells. Impulse activity in response to shadowing the median ocellus is recorded in a few fibers of the circumesophageal connectives. Picrotoxin blocks this shadow-induced activity. A model of the shadow reflex pathway is presented.     

Evaporative water loss of small vertebrates,as measured with an infrared analyzer

Evaporation is linearly and inversely related to absolute humidity at 26 degrees to 27 degrees C. The relative rate of loss in desert reptiles, rodents, and anurans is about 1:10:40. The maximum rate of water loss is about 2.5 and 5 times the basal rate, respectively, in pocket mice and sand lizards. The ratio of loss from lung to loss from skin is about 84:16 in kangaroo rats and 70:30 in rattlesnakes.     

Respiration of heart muscle as affected by oxygen tension

Isolated cat papillary muscles were exposed to gas mixtures containing carbon dioxide and oxygen. In muscles exposed during the second of three periods to 25 percent oxygen, the volume of oxygen consumed (Q(o2)) was depressed by 50 percent, but returned to the control level during a third period at 98 percent oxygen. The work capacity was not significantly altered if the partial pressure of oxygen was low.     

Venus: ionosphere and atmosphere as measured by dual-frequency radio occultation of mariner v

Venus has daytime and nighttime ionospheres at the positions probed by radio occulation. The main layers are thin by terrestrial standards, with the nighttime peak concentration of electrons being about two orders of magnitude below that of the daytime peak. Above the nighttime peak were several scale-height regimes extending to a radius of at least 7500, and probably to 9700, kilometers from the center of Venus. Helium and hydrogen at plasma temperatures of 600 degrees to 1100 degrees K seem indicated in the regimes from 6300 to 7500 kilometers, with cooler molecular ions in lower regions. Above the daytime peak a sharp plasmapause was discovered, marking a sudden transition from appreciable ionization concentrations near Venus to the tenuous conditions of the solar wind. This may be indicative of a kind of interaction of the magnetized solar wind with a planetary body that differs from the two different kinds of interaction characterized by Earth and by Moon. For Venus and probably for Mars, the magnetic field of the solar wind may pile up in front of the conducting ionosphere, form an induced magnetosphere that ends at the plasmapause, above which any ionosphere that tends to form is swept away by the shocked solar wind that flows between the stand-off bow-shock and the magnetopause. The neutral atmosphere was also probed and a surface reflection may have been detected, but the data have not yet been studied in detail. Results are consistent with a super-refractive atmosphere, as expected from Soviet measurements near the surface. Thus, two unusual features of Venus can be described in terms of a light trap in the lower atmosphere, and a magnetic trap in the conducting ionosphere.     

Cell sorting: automated separation of mammalian cells as a function of intracellular fluorescence

A system for high-speed sorting of fluorescent cells was able to sort mouse spleen cells from Chinese hamster ovarian cells after development of fluorochromasia. Highly fluorescent fractions separated after similar treatment from mouse spleen cells immunized to sheep erythrocytes were enriched in antibody-producing cells by factors of 4 to 10.     

尿素作种肥对棉种出苗率的影响

研究了尿素作种肥对棉种出苗率的影响.结果表明:种肥用尿素过多,影响棉花出苗.壤土和黏土施用量控制在90kg/hm2以下,砂土用量最多不要超过45 kg/hm2.     

亲鲍来源不同的杂交鲍生长情况比较

为通过杂交育种解决南日鲍种质退化问题以促进鲍养殖效益,分别选取2012年10月份开展的南日鲍(♀)与皱纹盘鲍大连群体(♂)、盘鲍日本群体(♂)杂交所得的苗种以及南日鲍自交所得的3种苗种,于2013年3月份在海区水质情况良好的同一渔排吊笼养殖进行对比试验,试验分为3组,每组2 500个鲍苗,试验390d左右,观察它们的生长情况,测定鲍的体长、体重,分别统计每组鲍的数量。结果表明:分苗前,杂交鲍苗的生长速度、度夏养殖成活率均显著高于自交所得鲍苗(P0.05);而南日鲍(♀)×盘鲍(♂)杂交所得鲍苗的生长速度和养殖成活率略高于南日鲍(♀)×皱纹盘鲍(♂),但差异不显著(P0.05);当年秋季分苗后,养殖鲍的生长速度和养殖成活率依次为:南日鲍(♀)×盘鲍(♂)南日鲍(♀)×皱纹盘鲍(♂)南日鲍(♀)×南日鲍(♂),且3组之间差异显著(P0.05)。说明在鲍养殖生产中,采用杂交育种改良和优化鲍种质是切实可行的,可显著提高鲍的生长速度和养殖成活率。