A synaptic vesicle protein with a novel cytoplasmic domain and four transmembrane regions

Complementary DNA and genomic clones were isolated and sequenced corresponding to rat and human synaptophysin (p38), a major integral membrane protein of synaptic vesicles. The deduced amino acid sequences indicate an evolutionarily highly conserved protein that spans the membrane four times. Both amino and carboxyl termini face the cytoplasm, with the latter containing ten copies of a tyrosine-rich pentapeptide repeat. The structure of synaptophysin suggests that the protein may function as a channel in the synaptic vesicle membrane, with the carboxyl terminus serving as a binding site for cellular factors.     

Social rank in house mice: differentiation revealed by ultraviolet visualization of urinary marking patterns

Ultraviolet light has been used to examine urine marks deposited by adult male house mice on filter paper on the floors of their cages during overnight tests. Both the urination frequency and the pattern in which urine was deposited on the filter paper depended upon social rank. Dominant males vigorously marked their entire cage floor, whereas subordinate males typically voided urine in only two to four pools in the corners of their cages.     

食品安全关键技术应用综合示范区运行模式

河南作为国家“十五”重大科技专项“食品安全关键技术应用的综合示范”课题承担省(市)之一,结合自身实际,选定小麦和猪肉2类大宗产品,以鹤壁市作为综合示范区,按照“从源头到餐桌”的运行链条,就其安全生产的关键技术进行集成配套,开展应用的综合示范。2年多来,通过总体规划,省、市联动,全面推进,形成了“科技支撑,政府推动,企业自律,意识提升”的食品安全关键技术应用综合示范区运行模式。     

应用脉冲试井分析低渗透油藏井间连通性

低渗透油藏脉冲试井难度大,脉冲计算点的取法直接影响脉冲压力反应曲线的解释结果。通过改变取法,分别把计算点取在1.25Δt、2.25Δt、1.5Δt处,可合理解释低渗透油藏脉冲压力反应曲线。对XF油田现场实际资料解释验证,其结果可准确分析低渗透油藏井间连通性。     

Neuronal geometry: determination with a technique of intracellular dye injection

In a study of the specificity of neuronal connections in lobster abdominal ganglia, the dye Procion Yellow M4RS was electrophoretically injected into identified cell bodies. This dye spreads into fine branches of cells, survives fixation and routine histological procedures, and permits the reconstruction of cell shapes through examination of serial sections of ganglia. Certain cells were found to have an internal bilateral symmetry. Repeated injection of the same cells in ganglia from different animals showed that cells have characteristic shapes and that the neuropil is highly structured. This method of dye injection should have general applicability in studies where a knowledge of the geometry of specific cells is important.     

Exotic Earths: forming habitable worlds with giant planet migration

Close-in giant planets (e.g., "hot Jupiters") are thought to form far from their host stars and migrate inward, through the terrestrial planet zone, via torques with a massive gaseous disk. Here we simulate terrestrial planet growth during and after giant planet migration. Several-Earth-mass planets also form interior to the migrating jovian planet, analogous to recently discovered "hot Earths." Very-water-rich, Earth-mass planets form from surviving material outside the giant planet's orbit, often in the habitable zone and with low orbital eccentricities. More than a third of the known systems of giant planets may harbor Earth-like planets.     

Slow synaptic excitation in sympathetic ganglion cells: evidence for synaptic inactivation of potassium conductance

The slow excitatory postsynaptic potential (EPSP) was investigated in frog sympathetic ganglion cells. In contrast to the increased conductance associated with other known EPSP's, during the slow EPSP resting membrane conductance was decreased. Electrical depolarization of the membrane potentiated the slow EPSP, whereas progressive hyperpolarization decreased its size and then reversed it to a hyperpolarizing potential (the opposite of the effect of membrane polarization on other EPSP's). The reversal potential of the slow EPSP was close to the potassium equilibrium potential. We propose that the slow EPSP, in contrast to classical EPSP's, is generated by an inactivation of resting potassium conductance.     

Euglena gracilis: formation of giant mitochondria

The addition of antimycin A (0.5 microgram per milliliter) to cultures of a bleached strain of Euglena gracilis in the logarithmic phase of growth on succinate as a carbon source results in (i) an interruption of growth for 24 hours and (ii) an increase in whole-cell respiration and the emergence of a novel succinoxidase activity within 2 to 4 hours. After 3 to 5 hours, the mitochondria enlarge, fuse, and form a sheathlike structure situated close to the periphery of the cell.     

杉木人工林木材酸性染料染色性能

以冻融循环预处理后的杉木木材为原料,采用酸性大红3R染料对其进行染色处理,通过改变染料浓度、染色时间、染色温度和促染剂用量,以上染率和色差为评价指标,研究处理条件与木材染色性能的关系,通过傅里叶变换红外光谱(FTIR)分析染料与木材结合方式,并利用场发射扫描电子显微镜(FESEM)观察染料在木材内的分布特征。结果表明,染料浓度、染色时间、染色温度和促染剂用量对上染率的影响均极显著(P<0.01),但对色差的影响除浓度仍表现极显著外,其它因素的影响均不显著(P>0.05);随着染料浓度增加、染色时间延长、染色温度升高和促染剂用量增大,上染率均呈先增大后降低的变化趋势,而木材的色差则随染料浓度增大而增大,随染色温度升高先增大后减小,随染色时间延长和促染剂用量增加呈先增大后减小并趋于平缓的变化趋势。傅里叶变换红外光谱分析与场发射扫描电子显微镜观察发现,染料与木材间通过物理吸附结合并以分子间团聚形式附着在木材管胞口、轴向管胞壁、木射线薄壁细胞等微观结构内。     

Calcium transient in presynaptic terminal of squid giant synapse: detection with aequorin

Microinjection of aequorin, a bioluminescent protein sensitive tocalcium, into the presynaptic terminal of the squid giant synapse demnonstrated an increase in intracellular calcium ion concentration during repetitive synaptic transmission. Although no light flashes synchronous with individual presynaptic : tion potentials were detected, the results are considered consistent with the hypothesis that entry of calcium into the presynaptic terminal triggers release of e synaptic transmitter substance.     

蓝色多胺型染料的超高固色效应研究

以四乙烯五胺为原料,合成了1,4-二氨基葸醌系蓝色四乙烯五胺型交联染料,并将其应用于丝绸和棉纤维染色,然后用2,4-二氯-6-（氨基苯-4’-磺酸酯乙基砜）均三嗪交联剂（DAST）,采用两浸两轧、焙烘工艺对染色纤维固色效应进行了研究．结果表明,在pH为7、交联剂质量浓度为20g／L时,该交联染料的最终固色率为99％,染色纤维耐洗、耐日晒及耐摩擦色牢度分别达为4-5级、4级和3—4级以上,与小分子活性染料相当,并具有一定防皱整理效果．     

Tetraethylammonium ions: effect of presynaptic injection on synaptic transmission

Tetraethylammonium ions were injected into the presynaptic axon of the squid giant synapse. Injection of these ions caused prolongation of the action potential with decreased out ward current. The prolonged spike was associated with increased release and prolonged activity of the transmitter substance. Although the amplitude of the postsynaptic potential increased with presynaptic depolarization, strong depolarization blocked transmitter re lease. In the injected presynaptic axon, transmitter release was blocked by 10(-6) gram of tetrodotoxin per milliliter. Transmitter release appears to be under control of presynaptic potential levels.     

Guanosine 3',5'-monophosphate in sympathetic ganglia: increase assoicated with synaptic transmission

Brief stimulation of cholinergic preganglionic nerve fibers resulted in an increase in guanosine 3',5'-monophosphate (cyclic GMP) in the bullfrog sympathetic ganglion. When the release of synaptic transmitter was prevented by a high-magnesium, low-calcium Ringer solution, stimulation of preganglionic nerve fibers did not increase cyclic GMP in the ganglion. The increase in cyclic GMP caused by preganglionic stimulation was also blocked by the muscarinic antagonist, atropine. The data indicate that the increase in cyclic GMP is associated with synaptic transmission and support the possibility that cyclic GMP may mediate the postsynaptic action of acetylcholine at muscarinic cholinergic synapses.     

Self-mode-locking of quantum cascade lasers with giant ultrafast optical nonlinearities

We report on the generation of picosecond self-mode-locked pulses from midinfrared quantum cascade lasers, at wavelengths within the important molecular fingerprint region. These devices are based on intersubband electron transitions in semiconductor nanostructures, which are characterized by some of the largest optical nonlinearities observed in nature and by picosecond relaxation lifetimes. Our results are interpreted with a model in which one of these nonlinearities, the intensity-dependent refractive index of the lasing transition, creates a nonlinear waveguide where the optical losses decrease with increasing intensity. This favors the generation of ultrashort pulses, because of their larger instantaneous intensity relative to continuous-wave emission.     

Synaptic transmission in the crayfish: increased release of transmitter substance by bacterial endotoxin

Bacterial endotoxin increases the frequency of miniature excitatory postsynaptic potentials, decreases facilitation, and increases the evoked excitatory postsynaptic potential without changing membrane resistance. These data indicate that endotoxin acts on the presynaptic nerve terminal by increasing the amount of transmitter substance released in response to an applied stimulus.     

Antibody-forming cells: population patterns after simultaneous immunization with different isoantigens

Spleen cells were obtained from chickens stimulated simultaneously with different erythrocytic antigens, and the proportions producing one and two antibodies were determined by the hemolytic-plaque technique. Most cells from birds immunized with two antigens of the same system (B) appeared to produce only one antibody. In a population of cells from birds immunized with antigens of different systems (A and B), a relatively high proportion of cells produced two antibodies.     

陇中旱地马铃薯不同种植模式对土壤温度和水分利用效率的影响

在陇中半干旱区进行了马铃薯7种不同种植模式的比较试验,研究了不同种植模式对耕层土壤温度、土壤含水量、马铃薯产量和水分利用效率的影响.结果表明:高垄覆盖地膜垄沟覆草的增温效果最明显,在8∶00、14∶00和20∶00时的平均土壤温度分别为19.77℃、29.22℃和26.94℃,较传统耕作分别提高了2.17℃、3.44℃和3.18℃;该模式下马铃薯产量和水分利用效率也最高,分别为24 279 kg.hm-2、67.61 kg.hm-2.mm-1,较传统耕作分别提高58.42%、46.03%.     

Colloidal nanocrystal shape and size control: the case of cobalt

We show that a relatively simple approach for controlling the colloidal synthesis of anisotropic cadmium selenide semiconductor nanorods can be extended to the size-controlled preparation of magnetic cobalt nanorods as well as spherically shaped nanocrystals. This approach helps define a minimum feature set needed to separately control the sizes and shapes of nanocrystals. The resulting cobalt nanocrystals produce interesting two- and three-dimensional superstructures, including ribbons of nanorods.