Gc、Pi蛋白亚型的快速微量电泳分析

用快速微量等电聚焦技术对190名北京地区汉族健康人血清Gc蛋白亚型、Pi蛋白亚型进行分型鉴定和基因频率调查.上样量为1.5μl,电泳和染色各0.5h.Gc^1F=0.4891,Gc^1S=0.2432,Gc²=0.2678.观察值与期望值吻合良好.(∑X²=1.404,0.7<P<0.8).Pi^M₁=0.7542,Pi^M₂=0.1808,Pi^M₃=0.0650,观察值与期望值吻合也良好,(∑X²=1.1233,0.7<P<0.8).     

Efficient plantlet regeneration from protoplasts isolated from suspension cultures of poplar (Populus alba L.)

We developed an efficient plant regeneration system from protoplasts for poplar (Populus alba L.). Protoplasts were isolated from 4-day-old suspension cultures derived from seed-induced calli with a yield of 6.96× 10⁶ cells/g fresh weight cells and then cultured at a concentration of 2.5×10⁵ cells/ml in NH₄NO₃-free Murashige and Skoog (MS) medium supplemented with 5 μM 2,4-dichlorophenoxyacetic acid (2,4-D), 0.05 μM thidiazuron (TDZ) and 0.5 M glucose as a osmoticum. The plating efficiency of the cultured protoplasts was calculated at 26.5% at day 7 and 31.7% at day 14. Cell colonies were observed after culturing for 4 weeks. Regenerated colonies were propagated through subculture in liquid MS medium supplemented with 5 μM 2,4-D. Buds were induced from regenerated calli on MS medium containing 10 μM kinetin or 1 μM TDZ. Regenerated shoots were rooted on half-strength MS medium, and the plantlets were transplanted in soil. Randomly amplified polymorphic DNA analysis did not detect any DNA polymorphism among the regenerated plants. Received: 7 March 1997 / Revision received: 16 June 1997 / Accepted: 5 July 1997     

细菌视紫红质光循环中间体M412的动力学初探

采用紫外可见吸收光谱技术和闪光光解技术,初步观察了细菌视紫红质(BR)分子在宽pH范围（2.1～12.3）内的特征吸收峰以及M₄₁₂的相对浓度和M₄₁₂的慢成分半衰期的变化,并对其结构和光循环功能进行了讨论.紫外可见吸收光谱实验结果显示：pH=5.0～10.0时,BR最大特征吸收峰值约为568 nm;pH＜5.0时,BR最大特征吸收峰发生红移;pH＞10.0时,BR最大特征吸收峰发生蓝移.闪光动力学光谱结果显示：pH为7.3～9.5时,M₄₁₂的相对浓度(M₀)基本稳定在0.038左右;pH＜7.3时,M₀逐渐减小;pH＞9.5时,M₀明显上升,在pH=11.8时达到最大值0.1355,随后又快速下降.pH为2.1～7.3时,M₄₁₂的慢成分半衰期(t^s_1/2)值在(4.1±1.1)ms左右;pH＞7.3时,t^s_1/2值急剧延长到40 677.4 ms.推测在高pH条件下,BR分子的光循环有新的路径和机理.     

Isolation and genetic characterization of streptomycin and chloramphenicol resistant mutants in the mossPhyscomitrella patens

Summary Mutant strains of the mossPhyscomitrella patens that were resistant to the antibiotics streptomycin and chloramphenicol were isolated following UV irradiation. Mutants resistant to streptomycin at 1.7×10⁻⁴ M showed both dominant and recessive Mendelian and inheritance patterns. Mutants resistant to streptomycin at 1.7 ￠ 10⁻⁴ M and to chloramphenicol at 3.1×10⁻⁴ M were, with one exception, cytoplasmically inherited.     

醋酸棉酚对红细胞膜功能的影响

本文报道醋酸棉酚对人红细胞膜功能和完整性的影响。棉酚浓度高于50μM可致红细胞溶血,10～40μM可促进K⁺外逸。1—2%牛血清白蛋白可以对抗这些效应．5—10μM棉酚明显抑制红细胞膜(Na⁺+K⁺)-ATP酶活性,Ki值6.0μM。     

Effects of iron chelates on the transferrin-free culture of rat dermal fibroblasts through active oxygen generation

Summary Effects of nonchelating and chelating agents at 10 mM on the serum-free culture of rat dermal fibroblasts were investigated. A strong iron-chelating agent, iminodiacetic acid (IDA), and a weak one, dihydroxyethylglycine (DHEG), decreased iron permeation into preconfluent fibroblasts. A weak iron-chelating agent, glycylglycine (GG), a nonchelating agent, N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid (HEPES), and human apotransferrin (10 μg/ml) increased the permeation with time. Iron may be essential for survival of fibroblasts because subconfluent fibroblasts exposed to 100 μM FeSO₄ in combination with transferrin, HEPES, or GG significantly decreased to release lactate dehydrogenase into the medium. Superoxide dismutase and dimethyl sulfoxide blocked the enzyme release, suggesting that superoxide and hydroxyl radical induce cellular damage but hydrogen peroxide (H₂O₂) generated by superoxide dismutation does not. GG significantly reduced H₂O₂ cytotoxicity. DHEG acted as a potent promoter of the iron-stimulated cellular damage if ascorbate or H₂O₂ was added to the medium. FeSO₄ and FeCl₃ (50 to 100 μM) individually combined with IDA maximally promoted fibroblast proliferation. Ascorbate increased formation of thiobarbituric acid-reactive substances from deoxyribose in the medium supplemented with FeSO₄ and either IDA or DHEG. Conversely, ascorbate decreased the formation in the medium with FeSO₄ and with or without other agents. Fibroblast proliferation may thus be stimulated through the active oxygen generation mediated by a redox-cycling between Fe³⁺ and Fe²⁺, which are dissolved in the medium at a high concentration, rather than through delivery of iron into the cells.     

鄱阳湖沉水植物区不同深度土壤甲烷排放对温度水分变化的响应

采集鄱阳湖沉水植物区0-10 cm和10-30 cm土壤样品,通过设置2个温度（18℃和28℃）和2个水分（淹水2 cm和土柱取出水面后的实际土壤水分含量）处理组合,进行持续2年的甲烷（CH₄）排放室内培养实验,以探讨不同深度土壤CH₄排放对温度、水分变化的响应差异,以及温度、水分和土层对湿地土壤CH₄排放的交互影响。结果表明：0-10 cm和10-30 cm土壤CH₄排放速率变化范围分别为0.01-3.63 μgCH₄-C kg^-1d^-1、0.02-1.99 μgCH₄-C kg^-1d^-1;均值分别为0.72和0.15 μgCH₄-C kg^-1d^-1。温度、水分和土层3因素及其交互作用均对土壤CH₄排放有显著影响（P<0.01）,且土层的影响最大。两水分处理下的CH₄排放对温度变化的敏感性均表现为0-10 cm（Q₁₀为1.78、3.26）高于10-30 cm土层（Q₁₀为1.04、1.08）。CH₄平均排放速率及累计排放量均表现为0-10 cm显著高于10-30 cm土层,且培养前期高于培养后期,显示基质有效性对土壤CH₄排放的重要影响。     

Zinc-induced changes in ionic currents of cardiomyocytes

The whole-cell voltage-clamp technique was applied to isolated ventricular myocytes to investigate the effects of extracellular and intracellular zinc application on L-type Ca²⁺ channel currents (I _Ca). Extracellular zinc exposure at micromolar concentration induced a reversible (with washout of ZnCl₂) reduction (30%) of I _Ca with no change in current-voltage relationship. On the other hand, an increase of intracellular free-zinc concentration, [Zn²⁺]_i, from normal (less than 1 nM) to approx 7 nM with 10 μM Zn-pyrithione exposure caused an inhibition of 33±6% in the peak of the I _Ca and altered the voltage dependency of L-type Ca²⁺ channels with a 10-mV left shift and a hump at around −40 mV in its current-voltage relation. In contrast, N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) strongly inhibited the I _Ca (42±2%), with only a small but detectable outward shift of the holding current measured at the end of the pulses. Zn-pyrithione and TPEN caused a reproducible decrease of the I _Ca. Interestingly, TPEN application, without Zn-pyrithione pretreatment, inhibited the I _Ca (35±2%) with no change in voltage dependency. Taken together, the results suggest that both extracellular and intracellular zinc increases under pathological conditions in cardiomyocytes can alter the I _Ca, but their effects are not in the same order and same manner. One should consider these possible side effects when it is suggested to be vital to cardiovascular cell integrity and functions.     

Similar Susceptibility to Excess Irradiance in Sun and Shade Acclimated Saplings of Norway Spruce [Picea Abies (L.) Karst.] and Stone Pine (Pinus Cembra L.)

We compared the responses of sun and shade acclimated saplings of Picea abies and Pinus cembra to excess photosynthetic photon flux density (PPFD) equivalently exceeding the level for saturating net photosynthetic rate (P _N). Exposure for 2 h up to 2000 μmol(photon) m⁻² s⁻¹ did not affect radiant energy saturated P _N. Photoinhibition of photosynthesis was indicated by a small (10 %) reduction of the potential efficiency of photosystem 2 as derived from measurements of chlorophyll fluorescence (F_V/F_M). However, the extent of F_V/F_M reduction and half-time for recovery were similar in sun and shade acclimated saplings of both species. Furthermore, the effect on F_V/F_M was not stronger when the plants were exposed to excess PPFD at 5 °C instead of 15 °C. Frost-hardening of plants increased slightly their resistance to excess PPFD. Establishment of these conifer saplings usually acclimated to shade in their natural habitat may hardly be endangered by a sudden increase of PPFD, e.g., by gap formation. This revised version was published online in August 2006 with corrections to the Cover Date.     

选育抗老化啤酒酵母提高啤酒风味稳定性的研究

对一株啤酒酵母青②进行紫外线诱变 ,在蛋氨酸浓度为 15g L的耐性平板上筛选获得一株A₂₇菌株。为使A₂₇菌株的蛋氨酸耐性特征稳定遗传 ,在 11℃、稀释率为0.035h^-1 的条件下对A₂₇菌株进行高浓度蛋氨酸 (20g/L)连续驯养 ,然后分离得到一株M^I₄菌。在锥形瓶中连续发酵5代后 ,与A₂₇菌株相比 ,M^I₄ 菌株发酵液中GSH浓度高44% ,TBA值低 24% ,主酵液RSV值高 77% ,且遗传稳定性明显提高 :连续传代 5次后 ,M^I₄ 菌株胞内GSH含量基本不变 ,而A₂₇菌则下降了22%。在相同的糖化和发酵工艺条件下 ,对优选株M^I₄和出发株啤酒酵母青②进行 1m3发酵罐中试。与出发株青②相比 ,两者的总高级醇与酯量几乎不变 ,常规指标没有显著差别 ,品尝风味也基本一致。但M^I₄菌株发酵液中GSH浓度提高了 30% ,TBA值降低了19% ,成品啤酒的RSV值则提高了92% ,表明优选株M^I₄是一株具有抗老化能力的优良啤酒酵母 ,能够提高啤酒的风味稳定性.     

Down regulation of CYP 1A1 by glucocorticoids in trout hepatocytes in vitro

Summary Short-term culture of rainbow trout (Onchorhynchus mykiss) hepatocytes was used to examine the effect of dexamethasone (DEX) on microsomal CYP 1A1 protein content and 7-ethoxyresorufin-O-deethylase (EROD) activity in vitro. Hepatocytes prepared by controlled collagenase digestion and plated at a density of 0.25 × 10⁶ cells/cm² in plastic culture dishes precoated with trout skin extract (7.6 μg skin protein/cm²) to facilitate cell attachment were maintained at 16° C. Cells were treated with DEX (10⁻⁹ to 10⁻⁷ M) or vehicle (dimethyl sulfoxide, DMSO) at 24 h. Microsomal CYP 1A1 protein content and EROD activities were measured at 72 h. Both CYP 1A1 protein as measured by Western blots using CYP 1A1 specific anti-sera and EROD activity were significantly lower in DEX (10⁻⁸ to 10⁻⁷ M)-treated hepatocytes compared to untreated (control) or DMSO-treated cells. The effect was dose dependent in that a gradual decrease of CYP 1A1 protein and EROD activities were seen with increasing doses of DEX (10⁻⁸ to 10⁻⁷ M). DEX at 10⁻⁹ M was ineffective. Concomitant addition of 10⁻⁶ M RU486, a type II specific glucocorticoid receptor antagonist, to hepatocytes treated with 10⁻⁷ M DEX abolished the DEX effect. RU486 at 10⁻⁸ M was ineffective. Spironolactone (10⁻⁸ to 10⁻⁶ M), a type I specific glucocorticoid receptor antagonist, did not counteract the DEX effect. RU486 or spironolactone (10⁻⁶ M) alone had no effect on CYP 1A1 under similar conditions. DEX thus down regulates CYP 1A1 in fish cultured hepatocytes and this regulation is mediated through the type II glucocorticoid receptor(s).     

Avocado shoot culture, plantlet development and net CO2 assimilation in an ambient and CO2 enhanced environment

Summary The proliferation and survival of avocado nodal cultures of juvenile origin were affected by the form and concentration of nitrogen. Optimum growth was achieved on modified Murashige and Skoog medium containing 67% KNO₃ and 33% NH₄NO₃ with total N of 40 mM supplemented with 100 mg l⁻¹ myo-inositol, 1 mg l⁻¹ thiamine HCl, 30 g l⁻¹ sucrose, and 4.44 μM BA with a 16-h photoperiod (120–150 μmol m⁻² s⁻¹). Proliferating shoots and plantlets were photosynthetically active. Better shoot growth and accumulation of higher biomass occurred in a CO₂-enriched environment than under ambient CO₂ conditions. CO₂ assimilation efficiency, however, was higher under the latter conditions than in a CO₂-enhanced environment, e.g., 31±7 and 17±2 μmol CO₂ m⁻² s⁻¹, respectively. The net CO₂ assimilation rates of in vitro grown plantlets were comparable to those of seedlings ex vitro.     

西藏双须叶须鱼年龄与生长特点研究

双须叶须鱼（Ptychobarbus dipogon Regan）隶属裂腹鱼亚科（Schizothoracinae）叶须鱼属（Ptychobarbus）,是西藏特有经济鱼类,2016年被列入中国脊椎动物红色名录,必须加快推动该鱼的养护工作。2013年2~3月份及2014年2~6月份,在雅鲁藏布江谢通门段与支流拉萨河上游段采集1 030尾双须叶须鱼样本,以脊椎骨作为年龄鉴定材料进行年龄与生长特点研究,以期分析和评价该类群鱼类资源情况。研究结果如下：双须叶须鱼样本中最大年龄为49龄,最小年龄为4龄;体重与体长关系是样本总体W=4.4×10^-5?SL^2.7688、雌鱼W_♀=5.0×10^-4?SL^2.3474、雄鱼W_♂=2.8×10^-5?SL^2.8414;体长生长方程为雌鱼L_t（♀）=431.8［1-e^-0.19（t+1.19）］,渐进体长L∞_（♀）=431.8 mm,拐点年龄为3.3龄,雄鱼L_t（♂）=367.6［1-e^-0.42（t+3.37）］,渐进体长L∞_（♂）=367.7 mm;体重生长方程为雌鱼W_t（♀）=767.40［1-e^-0.19（t+1.19）］^2.3474,雄鱼W_t（♂）=545.02［1-e^-0.42（t+3.37）］^2.8414;群体异速生长指数b=2.768 8与匀速生长指数3存在显著性差异,即P<0.05。研究表明双须叶须鱼体趋向低龄化,应当予以充分关注。     

谷氨酸棒状杆菌尿素传感器的研究

基于腺酶催化尿素分解产生氨,以氨气敏电极为基础电极,用含脲酶丰富的谷氨酸棒状杆菌研制成测定尿素的微生物传感器.在30℃、pH8.0、0.1mol/L磷酸盐缓冲液中,该传感器的线性范围为1.1×10^-4～1.4×10^-2mol/L,斜率为51.2mV/decade,检测下限为1.0×10^-5mol/L,寿命可达45d.考察了传感器响应初速和底物浓度之间的关系,测定了微生物膜中脲酶的表观米氏常数K_m及最大响应初速v_m.     

Callus proliferation from leaf protoplasts using phenylurea type cytokinin, 4-PU,inBetula platyphylla VAR.Japonica

Summary Protoplasts were isolated from leaves ofBetula platyphylla var.japonica using a 0.6M mannitol solution containing 1% Cellulase Onozuka R-10 and 1% Driselase. The cell division and colony formation were largely enhanced using Murashige and Skoog (1962) liquid medium at half strength (1/2 MS), containing 0.6M mannitol, 0.09M sucrose, and factorial combinations of 0.1–30 μM N-(2-chloro-4-pyridyl)-N′-phenylurea (4-pu) and 0.1–10 μM 1-naphthaleneacetic acid (NAA) or 0.1–30 μM 2,4-dichlorophenoxyacetic acid (2,4-D). The optimal protoplast density was 5–7 × 10⁴/ml. Continuous callus proliferation from protoplasts was achieved by transferring colonies to fresh 1/2 MS agar medium containing 1 μM NAA and 1 μM 4-pu with no mannitol. It appeared that supplementation of the medium with phenylurea type cytokinin, 4-pu gave the successful callus proliferation from the protoplasts ofB. platyphylla.     

Effects of the Ca ionophore A23187 on zinc-induced apoptosis in C6 glioma cells

Zinc ions are essential, but at elevated concentrations, they also have toxic effects on mammalian cells. Zinc plays a crucial role in cell proliferation and differentiation and it even protects cells against apoptosis caused by various reagents. On the other hand, zinc at high concentrations causes cell death that was characterized as apoptotic by internucleosomal DNA fragmentation, formation of apoptotic bodies, and breakdown of the mitochondrial membrane potential. In the present work, a clone of rat C6 glioma cells that was resistant to toxic effects of ZnCl₂ up to 250 μM was employed to study the effect of the ionophore A23187 on zinc-induced apoptosis. Neither 150 μM Zn²⁺ nor 100 nM A23187 alone caused apoptosis as measured by internucleosomal DNA fragmentation. However, combined exposure of C6 cells to 100 nM A23187 and 150 μM Zn²⁺ for 48 h was effective in inducing apoptosis. Because the so-called calcium ionophore A23187 is not specific for Ca²⁺ ions but also transports Zn²⁺ with high selectivity over Ca²⁺, we investigated whether this substance promoted the uptake of Zn²⁺ ions into C6 cells. Employing the zinc-specific fluorescence probe Zinquin, we observed that the very low concentration of 1.9 nM A23187 significantly and rapidly raised the intracellular mobile Zn²⁺ content. Analysis by atomic absorption spectroscopy revealed that incubation with 1.9 nM A23187 caused a doubling of the total intracellular zinc level within 60 min. We conclude that the apoptosis evoked by the combined action of Zn²⁺ and A23187 was the result of enhanced Zn²⁺ influx evoked by the ionophore, resulting in higher intracellular zinc levels.     

人外周淋巴细胞多巴胺受体的测定方法研究

用[³H]-spiperone作为特异配体,与人的淋巴细胞膜上多巴胺受体进行结合反应,在淋巴细胞浓度1×10⁶个/ml,反应温度37℃,反应时间60min条件下,此结合反应具有低容量和高亲和力的特点。K_d=8.87nmol/L, B_max=181fmol/l×10⁶个淋巴细胞。用单点法分析,34例正常人特异结合平均值为139(fmol/1×10⁶LC)。此法用血量少重复性优,从而适用于临床研究。     

内蒙古草原常见植物叶片δ13C和δ15N对环境因子的响应

在中国东北样带沿线的内蒙古草原地区采集了一些常见植物的叶片样品,并测定其δ¹³C和δ¹⁵N值,分析了其统计学特征以及对环境因子(年平均降雨量和温度)的响应模式。发现东北样带草原区同时存在C₃和C₄两种不同光合途径的植物,但是C₃植物占主导地位,C₄植物数量有限。C₃植物叶片δ¹³C随着年平均降雨量和年平均温度的升高而显著降低,反映了此区域C₃植物δ¹³C受控于降水量和温度。C₄植物的叶片δ¹³C值随着降雨量的增多而有轻微升高的趋势,但是C₄植物的叶片δ¹³C值对年平均温度的响应不敏感。不论对C₃植物还是C₄植物而言,叶片δ¹⁵N都随降雨量增加而显著降低,即干旱区的植物叶片δ¹⁵N大于湿润地区,这说明降水是影响植物叶片δ¹⁵N的一个重要因素。然而两者叶片δ¹⁵N对温度的响应不敏感。     

不同交联方法制备的免疫毒素及其体内外特性

用三种不同的异型双功能交联剂把单抗和完整蓖麻毒素连接起来,经适当纯化获得了高活性免疫毒素(ITs),体外试验中蛋白质合成抑制50％的浓度IC₅₀达到2.7×10^-12mol/L.以二硫键连接的ITs比硫醚键连接的ITs细胞毒性高5—10倍(P<0.05),而硫醚键连接的ITs在动物体内代谢慢1倍,且其原型药物维持时间更长,稳定性更好。两类ITs在体内的代谢产物也不相同。     

Modified single node culture method—a new micropropagation method for chickpea

Summary Chickpea was micropropagated by axillary shoot proliferation (ASP) and modified single node culture (MSNC) methods. Maximum propagule proliferation occurred on Murashige and Skoog (MS) medium enriched with 1–10 μM N⁶-benzyladenine and 0.01 μM α-naphthaleneacetic acid. The propagules were rooted on MS medium containing 1 μM 3-indolebutyric acid and B₅ vitamins. Regenerated plants were fertile and phenotypically similar to control plants grown from seed. The MSNC method was four times more efficient than the ASP method in terms of the number of plants produced per explant.