不同生育时期干旱处理对春玉米保护酶活性及产量的影响

不同生育时期干旱处理均使春玉米功能叶片中CAT活性和POD活性降低,CAT在吐丝期干旱处理时其活性降低幅度最大,达52.97%;POD在抽雄期干旱处理时其活性降低幅度最大,达32.01%;不同生育时期干旱处理均使功能叶片中MDA含量增加,苗期干旱处理时增加幅度最大,达57.77%。不同生育时期干旱处理对平均穗粒数影响最大的时期为抽雄期;对百粒重影响最大的时期为灌浆期;对单株产量影响最大的时期为抽雄期。对各处理单株产量进行方差分析说明,除成熟期干旱处理与对照相比差异不显著外,其它各生育时期干旱处理与对照相比差异均达到极显著水平,即不同生育时期干旱处理产量均下降,以孕穗期到开花期干旱处理产量下降幅度最大,减产幅度在58.73～75.41个百分点之间。     

植物源POD和CAT的筛选及其与重金属的相互作用

采用分光光度法和滴定法对南瓜、冬瓜、小白菜、红萝卜等30种植物组织中的过氧化物酶(POD)和过氧化氢酶(CAT)的活性及其与重金属之间的相互作用进行了研究,以筛选出适用于重金属生物传感器研制的植物源POD和CAT.结果表明:南瓜皮中POD的活性最高,其次是白萝卜和黄豆芽(胚乳);黄豆芽(胚乳)中CAT活性最高,其次是小白菜、冬瓜皮和黄瓜皮等.不同植物中的POD和CAT的活性有差异,其对同一种重金属的敏感性也有不同程度的差异.南瓜皮是较理想的POD酶源;冬瓜皮、青椒、黄豆芽(胚乳)则是较佳的CAT酶源.在本试验条件下,Cu和Hg对POD活性具有抑制作用,Cu、Pb和Hg对CAT的活性也具有不同程度的抑制作用.结果表明,可以利用酶抑制法原理构建POD生物传感器以检测Cu和Hg,构建CAT生物传感器以检测Cu、Pb和Hg.     

Translational potentiation of messenger RNA with secondary structure in Xenopus

Differential translation of messenger RNA (mRNA) with stable secondary structure in the 5' untranslated leader may contribute to the dramatic changes in protein synthetic patterns that occur during oogenesis and early development. Plasmids that contained the bacterial gene chloramphenicol acetyltransferase and which encoded mRNA with (hpCAT) or without (CAT) a stable hairpin secondary structure in the 5' noncoding region were transcribed in vitro, and the resulting mRNAs were injected into Xenopus oocytes, eggs, and early embryos. During early oogenesis, hpCAT mRNA was translated at less than 3 percent of the efficiency of CAT mRNA. The relative translational potential of hpCAT reached 100 percent in the newly fertilized egg and returned to approximately 3 percent after the midblastula transition.     

Bovine leukemia virus long terminal repeat: a cell type-specific promoter

The functional activity of the promoter unit contained within the long terminal repeat (LTR) of bovine leukemia virus (BLV) was examined by monitoring transient expression of a heterologous gene placed under its control. Various cell lines were transfected with recombinant plasmids carrying the bacterial chloramphenicol acetyltransferase (CAT) gene coupled to the BLV LTR (pBL-cat). Transient expression of CAT activity directed by the BLV LTR was observed only in the established BLV-producer cell lines derived from fetal lamb kidney (FLK) cells and bat lung cells. The amount of CAT activity transiently expressed in FLK-BLV cells was decreased approximately tenfold by deletion of LTR sequences located within a region 100 to 170 nucleotides upstream of the RNA start site. Surprisingly, removal of the region 50 base pairs downstream of the RNA initiation site to the 3'-end of the LTR reduced the expression of CAT activity by 87 percent. The BLV LTR thus appears to be an unusual promoter unit, functioning in a cell type-specific manner and possessing sequences on both the 5' and 3' sides of the RNA start site that influence gene expression.     

Simplify the interpretation of alert lists for clinical mastitis in automatic milking systems

Based on sensor measurements, an automatic milking system (AMS) generates mastitis alert lists indicating cows which are likely to have clinical mastitis (CM). Because of the general assumption of equal probabilities of developing CM for all cows, all alerts on the list have the same success rate. As a consequence, it is not possible to rank-order the alerts in terms of their likelihood of CM. In practice, the performance of a CM detection system is not only based on the sensitivity (SN) and specificity (SP) of the system, but is also influenced by the prior probability of a cow having CM. This study illustrates the idea of using cow-specific prior probabilities of CM, based on non-AMS information, to provide a rank-order on the alerts from an AMS. A tree-augmented naive Bayesian network was trained from available data to determine these cow-specific prior probabilities for CM. The graphical structure of the network and the probability tables for its variables in the network were based on data from 274 Dutch dairy herds that recorded each case of CM over an 18-month period. The final data set contained information on a total of 5363 CM cases derived from 28,137 lactations and 22,860 cows. The available prior cow information (parity, days in milk, season of the year, somatic cell count history and CM history) was included as variables in the network. By combining the cow-specific prior probabilities of CM with the SN and SP of the detection system of the AMS, the computed success rates can be used to discriminate between CM alerts. Our illustrations indicate that the success rate might range from 3 to 84%, while assuming an equal overall probability would result in a success rate of 21%. Using the computed success rates, the CM alerts on an alert list can be rank-ordered, thereby providing the dairy farmer information about which cows have the highest priority for visual inspection for CM.     

The greenhouse effect: science and policy

Global warming from the increase in greenhouse gases has become a major scientific and political issue during the past decade. That infrared radiation is trapped by greenhouse gases and particles in a planetary atmosphere and that the atmospheric CO(2) level has increased by some 25 percent since 1850 because of fossil fuel combustion and land use (largely deforestation) are not controversial; levels of other trace greenhouse gases such as methane and chlorofluorocarbons have increased by even larger factors. Estimates of present and future effects, however, have significant uncertainties. There have also recently been controversial claims that a global warming signal has been detected. Results from most recent climatic models suggest that global average surface temperatures will increase by some 2 degrees to 6 degrees C during the next century, but future changes in greenhouse gas concentrations and feedback processes not properly accounted for in the models could produce greater or smaller increases. Sea level rises of 0.5 to 1.5 meters are typically projected for the next century, but there is a small probability of greater or even negative change. Forecasts of the distribution of variables such as soil moisture or precipitation patterns have even greater uncertainties. Policy responses range from engineering countermeasures to passive adaptation to prevention and a "law of the atmosphere." One approach is to implement those policies now that will reduce emissions of greenhouse gases and have additional societal benefits. Whether the uncertainties are large enough to suggest delaying policy responses is not a scientific question per se, but a value judgment.     

SA对稻根和愈伤组织CAT和POD活性的影响

实验结果表明 ,一定浓度 (0 .0 1～ 1 .0mmol/L)的水杨酸 (SA)对稻根和愈伤组织中的过氧化氢酶 (CAT)和过氧化物酶 (POD)的活性有明显的抑制作用 ,且SA浓度越高 ,其抑制作用总体上越强 ;稻根和愈伤组织的粗酶提取液经SA处理后 ,CAT和POD的活性也受到明显抑制 ;SA很可能在稻根等非绿色组织的抗病反应中起着信号的作用     

魔芋与软腐病菌互作中的生理生化指标变化

以花魔芋健康植株为试验材料,人工接种魔芋软腐病菌后,采用105℃烘干称质量法和CO2红外线分析仪分别测定植株含水量和呼吸速率,采用愈创木酚法和紫外吸收法分别测定植株中过氧化物酶(POD)、过氧化氢酶(CAT)活性。结果表明,接种后的植株含水量未发生变化,呼吸速率增大;在接种病菌第3天后2种酶活性明显增强,其中POD在达到峰值后迅速下降至原有水平,而CAT则在达到峰值后维持较长的时间。     

Early results from the infrared astronomical satellite

For 10 months the Infrared Astronomical Satellite (IRAS) provided astronomers with what might be termed their first view of the infrared sky on a clear, dark night. Without IRAS, atmospheric absorption and the thermal emission from both the atmosphere and Earthbound telescopes make the task of the infrared astronomer comparable to what an optical astronomer would face if required to work only on cloudy afternoons. IRAS observations are serving astronomers in the same manner as the photographic plates of the Palomar Observatory Sky Survey; just as the optical survey has been used by all astronomers for over three decades, as a source of quantitative information about the sky and as a "roadmap" for future observations, the results of IRAS will be studied for years to come. IRAS has demonstrated the power of infrared astronomy from space. Already, from a brief look at a miniscule fraction of the data available, we have learned much about the solar system, about nearby stars, about the Galaxy as a whole and about distant extragalactic systems. Comets are much dustier than previously thought. Solid particles, presumably the remnants of the star-formation process, orbit around Vega and other stars and may provide the raw material for planetary systems. Emission from cool interstellar material has been traced throughout the Galaxy all the way to the galactic poles. Both the clumpiness and breadth of the distribution of this material were previously unsuspected. The far-infrared sky away from the galactic plane has been found to be dominated by spiral galaxies, some of which emit more than 50 percent and as much as 98 percent of their energy in the infrared-an exciting and surprising revelation. The IRAS mission is clearly the pathfinder for future missions that, to a large extent, will be devoted to the discoveries revealed by IRAS.     

纳米铜对大鼠肝脏毒性相关蛋白过氧化氢酶的分离鉴定及生物信息学分析

【目的】分离和鉴定纳米铜对大鼠肝脏毒性相关蛋白过氧化氢酶(catalase, CAT),探讨CAT在毒性发挥中的作用,为揭示纳米铜对肝脏毒性机制提供依据。【方法】应用2-DE技术和PDQuest 8.0软件在大鼠肝脏蛋白组中筛选纳米铜对肝脏毒性差异蛋白,经质谱鉴定后进行生物信息学分析。【结果】筛选到下调的差异蛋白点6602和7702与肝毒性相关,鉴定均为CAT蛋白;其性质稳定,有一定亲水性,无信号肽,定位于细胞质,可能属于非分泌性蛋白,含有过氧化氢酶活性位点64FDRERIPERVVHAKGAG80和过氧化氢酶亚铁血红素配合基位点354RLFAYPDTH362等功能位点;无规则卷曲、α螺旋和延伸链是其主要的二级结构元件,并预测了其三级结构图;同源性分析表明,大鼠的CAT与其它8个物种有较高同源性,并构建了CAT 蛋白的系统进化树。【结论】纳米铜通过下调大鼠肝脏中CAT蛋白表达,引起肝细胞氧化应激损伤,可能是其发挥毒性作用的途径之一。     

嫁接茄子苗期黄萎病抗性生理指标的研究

本文研究了在接种条件下,以“托鲁巴姆”为砧木,“墨茄”为接穗的嫁接茄子和自根茄子(CK)的相对电导率、可溶性糖的相对渗出率、丙二醛(MDA)含量以及CAT、POD、PPO活性的变化与黄萎病抗性的关系。结果表明,嫁接茄子抗黄萎病能力明显高于对照;相对电导率、可溶性糖的相对渗出率、丙二醛(MDA)含量依次为砧木<嫁接株<对照;CAT、POD、PPO的活性依次为砧木>嫁接株>对照。说明丙二醛(MDA)含量的降低和CAT、POD、PPO活性的提高是嫁接茄子获得抗病性的重要生理原因。     

赤霉菌粗毒素对小麦幼苗活性氧代谢的影响

比较赤霉菌粗毒素液或外源SA预处理抗病和感病小麦幼苗不同时间,叶片活性氧代谢变化。结果表明：赤霉菌粗毒素液处理小麦幼苗根部2—48h后．O2^-产率先增加后降低,感病品种（川麦28）H2O2含量逐渐增加;用外源SA预处理小麦幼苗叶片2h后再用赤霉菌粗毒素液处理小麦幼苗根部2—48h,抗、感病品种的O2^-产率和H2O2含量均明显提高,且抗病品种（89107）先于感病品种达到其峰值,粗毒素液处理24h后抗性品种保护酶（SOD,CAT和POD）活性比感病品种的高。抗病品种PAL活性变化对SA预处理响应强烈。SA可能作为信号分子之一,诱发小麦幼苗对赤霉菌粗毒素液产生一定的系统抗性。     

草坪草褐斑病菌粗毒素液对寄主叶片防御酶体系的影响

分别利用草坪草褐斑病菌粗毒素5倍稀释液和10倍稀释液接种盆播坪草高羊茅,1周内逐天采集处理叶片,测定叶片防御酶(PAL、POD、PPO、CAT)活性变化。结果表明,坪草高羊茅叶片经粗毒素液处理1周内,PAL、POD、PPO活性较对照均有不同程度的提高,其总体变化趋势为先升高后降低,并且高浓度毒素处理较低浓度毒素处理的酶活性高,而经毒素处理后的坪草叶片CAT酶活性较对照却呈现下降的趋势。     

盐胁迫对榅桲种子萌发率、成苗率和酶活性的影响

以新疆苹果型榅桲成熟种子为试材,探讨了Na2SO4和NaCl两种盐胁迫对木日皿木孛种子萌芽率、成苗率、SOD、POD、CAT酶活性的影响,结果显示:随着两种盐浓度的增大,发芽率和成苗率均呈下降趋势;NaCl胁迫时,SOD、CAT活性均随着盐浓度的增大呈先上升后下降趋势,POD活性呈上升趋势;Na2SO4 胁迫时,随着盐浓度的增大,POD、 CAT活性呈先上升后下降趋势,SOD活性呈降低趋势.不同种类盐胁迫下,木日皿木孛种子的耐盐机制不同.     

Instrumental neutron activation analyses of lunar specimens

Ten Apollo 11 specimnens were divided into 24 samtples. Sodillim contents of 8 diverse specimens clluster tightly abolit 0.3 percent. Plagioclase separated from sample 10044 contains aboltt 1.09 percent Na; barium is not enriched in the plagioclase separate. Contents of the rare earths are strikingly high, and relative abtmndances resemble those of calcium-rich achondrites or abyssal basalts but are depleted in Eu by factors of 2 to 3 and in La by about 20 percent. The plagioclase separate is enriched in Eu and pyroxenes (and opaqtte minerals are Eu-depleted. Fine fractions of 10044 are abotit 20 to 40 percent richer in most rare earths (50 percent for Eu) than coarse fractions, probably becaitse of the presence of small grains in which rare earths are mnarkedly concentrated. "Microgabbro" 10045 is imnpoverished, relative to the soil, in rare eartlhs and Hf. Ratios by mass of Zr to Hf are comlparatively low. Abttndances of Mn, Co, Fe, Sc and Cr stiggest systematic differences between igneous rocks on one hanid and breccias and "soil" on the other. Fromn the Co abuindances, no more than about 3 percent of the present "soil" can consist of chondritic mleteorite conitamination.     

二溴海因对吉富罗非鱼血浆的氧化胁迫效应

采用半静态水质接触染毒法,研究不同浓度(0、0.06、0.3、1.5 mg·L^-1)、不同时间(1、2、4、8、16、26 d)下二溴海因对吉富罗非鱼血浆总还原性谷胱甘肽(T-GSH)、氧化型谷胱甘肽(GSSG)、谷胱甘肽-S-转移酶(GST)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽还原酶(GR)、谷胱甘肽过氧化物酶(GPx)及总抗氧化能力(T-AOC)的影响。结果表明:随着暴露时间的延长,血浆SOD、GR先降低后趋于稳定,T-GSH、GSH/GSSG、CAT、GST呈先升高后下降的趋势,且16 d出现显著性升高,GPx在1 d和16 d时被诱导,T-AOC仅在16 d时被诱导。CAT、GPx、T-GSH、GSH/GSSG、T-AOC等指标表现出浓度依赖现象,T-AOC与二溴海因呈剂量效应关系。除CAT、GR外,解除胁迫10 d后各抗氧化指标均未恢复到正常水平。上述结果显示,二溴海因对吉富罗非鱼血浆的抗氧化系统有显著的影响, T-AOC宜作为生物标志物,高浓度的二溴海因暴露能造成血液中抗氧化系统的不可逆损伤。     

低功率CO_2激光、TDP及其它红外辐射对鱼类生长发育影响的研究

本试验应用不同剂量的低功率CO_2激光、TDP及其它红外光源照射鲤、鲫、草鱼、鲢、鳙的孵化期鱼卵,以观察其鱼胚、稚鱼、鱼苗发育生长情况。试验结果证实,一定剂量的照射处理可提高鱼卵孵化率10～40％,鱼苗成活率20～40％,促进鱼胚、稚鱼和鱼苗的生长发育,增强其抗病抗逆能力,提高鱼苗的整齐度和摄食能力。同时通过试验观察证实上述生物刺激效应是一种“非热效应”,且有较长的后续作用。     

豫楸1号4种砧木嫁接苗在干旱胁迫下保护酶系统的变化

用盆栽自然干旱法对豫楸1号4种砧木嫁接苗进行干旱胁迫。在胁迫过程中,测定了超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的变化。结果表明:在干旱胁迫下,豫楸1号4种砧木嫁接苗保护酶活性(SOD、POD、CAT)均随着干旱胁迫增加而呈现先上升后降低的变化趋势,其中POD、CAT的活性变化滞后于SOD。金丝楸砧木嫁接苗的保护酶值比其他嫁接苗大。金丝楸砧木嫁接苗的SOD值与梓树嫁接苗呈0.05水平显著差异,其CAT活性与灰楸嫁接苗、梓树嫁接苗呈0.05水平显著差异。从保护酶活性变化可以看出,SOD、CAT在清除氧离子自由基方面起到关键作用,豫楸1号4种砧木嫁接苗抗旱能力强弱依次为金丝楸嫁接苗>自砧苗>灰楸嫁接苗>梓树嫁接苗。     

Is there any chlorine monoxide in the stratosphere?

A ground-based search for stratospheric chlorine monoxide was carried out during May and October 1981 with an infrared heterodyne spectrometer in the solar absorption mode. Lines due to stratospheric nitric acid and tropospheric carbonyl sulfide were detected at about 0.2 percent absorptance levels, but the expected 0.1 percent lines of chlorine monoxide in this same region were not seen. Stratospheric chlorine monoxide is less abundant by at least a factor of 7 than is indicated by in situ measurements, and the upper limit for the integrated vertical column density of chlorine monoxide is 2.3 x 10(13) molecules per square centimeter at the 95 percent confidence level. These results imply that the release of chlorofluorocarbons may be significantly less important for the destruction of stratospheric ozone than is currently thought.     

热红外遥感对马尾松林松材线虫病早期响应研究

松材线虫病由于传播速度快、致死率高等特点也被称“松树的癌症”,早期监测非常重要。基于Landsat 8 TIRS热红外遥感数据评估绿色攻击阶段的植被温度的异常变化，并探究其监测潜力。应用2018年江西省吉安市万安县的Landsat 8 TIRS遥感数据，通过单窗算法反演地表温度(LST)。以30个100 m×100 m样地的受害马尾松林的枯梢率为指标，分别开展5月(绿色阶段)、7月(绿色攻击阶段)及11月(红褐色-灰色阶段)3个不同月份的LST与枯梢率(SDR)的相关性分析。对比分析热红外和Sentinel-2光学数据在早期监测能力上的差异。结果表明，1)Landsat 8反演的地表温度LST分布合理，对虫害区域有响应；2)LST与枯梢率在5月(0.01相似文献