在水生与气生状态下石莼光合作用对光照和温度的响应

如何对付由于高潮时的水生状态与低潮时的气生状态高频率循环所导致的不同环境条件,是潮间带海藻的光合作用所面临的独特问题。对采自汕头沿岸的石莼(Ulva lactuca)在水生和气生不同状态下光合作用对光照和温度的响应特性进行了测定,以探讨这种常见的潮间带绿藻在潮汐循环背景下的光合特性。在气生状态下,光饱和净光合速率(Pmax)随气生暴露时间的变化模式可以很好地用三次方程进行描述,而温度影响方程的系数;当水分损失为15％时,石莼的Pmax增加至最大值,然后Pmax随进一步脱水而下降,在水分损失为80％时下降至0。温度对Pmax的影响在水生状态下比在气生状态下更大。气生状态下（充分水化）Pmax在10℃时显著小于水生状态下的值,而在30℃时则相反。在10℃时,气生干出时间在6 h 以内,或在20℃时,气生干出时间在2.2 h 以内,石莼的净碳固定量在气生状态下比在水生状态下要大;而在30℃时,在气生状态下的净碳固定量比总是小于在水生状态下的净碳固定量。认为石莼在低潮气生状态下与在高潮水生状态下光合特性及净碳固定存在差异,但这种差异与环境温度及叶状体的水分状态有关。     

北柴胡营养器官中主要化学成分的组织化学定位及其含量比较

应用植物解剖学、组织化学定位和植物化学方法,研究了北柴胡各营养器官中柴胡皂苷和黄酮类化合物的积累分布状态及其含量变化。结果表明,柴胡皂苷在根中分布在中柱鞘和次生韧皮部中;在茎中主要分布在表皮、棱角处的厚角组织以及位于皮层和髓中的分泌道的上皮细胞中;在叶中,则分布在表皮细胞和整个叶肉组织中。而黄酮类化合物在茎中分布在表皮、棱角处的厚角组织、皮层、髓射线和髓鞘细胞中;在叶中,则主要分布在表皮和位于上下表皮内的厚角组织中。同时,北柴胡中柴胡总皂苷在根、茎、叶中的含量的变化规律为根>叶>茎;而总黄酮在根、茎、叶中的含量的变化规律为叶>茎>根;且在叶中含量相当高,从而为北柴胡的综合利用提供依据,对合理利用药材和保护北柴胡资源也有一定意义。     

稻-麦轮作系统土壤水解酶及氧化还原酶活性对开放式空气CO2浓度增高的响应

研究了FACE条件下(CO2浓度增加200μmol·mol^-1)水稻、小麦不同生育期0～10cm土层土壤脲酶、磷酸酶、芳基硫酸酯酶、脱氢酶活性的变化．结果表明,FACE条件下,土壤脲酶活性在冬小麦生育前期低于对照,在孕穗期高于对照;在水稻生育前期高于对照,在成熟期低于对照．磷酸单酯酶活性在冬小麦生育期高于对照;在水稻分蘖期高于对照,在生育后期(拔节期、抽穗期和成熟期)低于对照．芳基硫酸酯酶活性在小麦越冬期和孕穗期低于对照,在分蘖期和成熟期高于对照;在水稻生育期间均高于对照．脱氢酶活性在小麦和水稻的生育前期低于对照,在后期高于对照．     

动物“恋”歌

在蔚蓝的天空下,在葱绿的原野上,在荡漾的湖泊中,鸟儿在比翼双飞中享受快乐的时光,痴情的狼成对奔跑在无尽的旷野,被人唾弃的狐狸其实是典型的情种,鸳鸯的不离不弃成为古今中外歌颂的主题,这些自然界最美丽动人的画卷     

海水盐度、温度对文蛤稚贝生长及存活的影响

在实验室条件下,研究了不同盐度（19个梯度）、温度（17个梯度）对文蛤稚贝生长和存活的影响.结果表明：文蛤稚贝的适宜生存盐度在6.5～39.5,最适生存盐度在9.0～31.0,适宜生长盐度在7.3～38.7,最适生长盐度在15.0～23.0;其适宜生存温度在4.0 ℃～36.1 ℃,适宜生长温度在7.0 ℃～35.4 ℃,较适宜生长温度在17 ℃～33.5 ℃,最适生长温度在24 ℃～27 ℃.文蛤稚贝对高温度、低盐度有较强的适应性.     

运用组织芯片技术检测ndrg2、c-myc在人甲状腺肿瘤中的表达及分析

目的:检测ndrg2、c-myc在人甲状腺肿瘤中的表达,探讨ndrg2、c-myc在人甲状腺肿瘤中的表达模式.方法:运用甲状腺组织芯片,通过免疫组化染色,检测ndrg2、c-myc在人甲状腺肿瘤中的表达,并进行量化评分,分析ndrg2表达与c-myc表达两者之间可能存在的负调控关系.结果:ndrg2在甲状腺癌组织中呈阴性表达,在甲状腺腺瘤组织中呈弱表达或不表达趋势,在正常甲状腺组织中高表达.而c-myc在甲状腺癌组织中呈高表达,在甲状腺腺瘤组织中不表达或仅呈部分弱表达,在正常甲状腺组织中呈阴性表达.统计结果分析显示,ndrg2与c-myc在人甲状腺组织中的表达呈负相关.结论:ndrg2、c-myc在人甲状腺肿瘤中的表达呈负相关,由此推测NDRG2可能受到C-MYC的负调控.     

国外动态

美国发现可在有氧条件下生产H2的细菌美国华盛顿大学等机构研究人员在英国《自然:通讯》杂志上发表报告说,他们发现1种细菌可以在有O2存在的自然条件下生产H2,有望成为较廉价的H2来源。这种名为"蓝藻菌51142"的细菌在白天和夜晚的生理活动不同。在白天有光线的时候,它可以进行光合作用,生成O2和糖分;而在夜晚,它会燃烧白天生     

新书介绍

质谱技术丛书——有机质谱在生物医药中的应用 本书深入浅出地论述了有机质谱在生物医药学中的应用,全书共6章,分别介绍了有机质谱在蛋白质组学中的应用、生物质谱在生物分子间非共价键相互作用研究中的应用、糖基化蛋白质的生物质谱分析、质谱技术在天然药物研究中的应用、质谱在组合化学研究中的应用、串联质谱技术与药代动力学和药物代谢研究。     

春天的脚步

三月是大地回暖、鸟语花香、春光明媚的季节,历经严冬的考验,春日的阳光照在身上倍觉温暖。在这里,我们满怀喜悦地告诉大家,在众多编委的大力支持下,截至二月底的统计显示,《学报》在2011年最初两个月中被引用的情况已经创造了历史最好记录。在过去十年中,《学报》     

恐龙蛋壳的生物力学性质(Ⅵ)──在外力作用下恐龙蛋壳结构的稳定性

应用薄壳理论分析五种类型恐龙蛋壳的受力特性,求出它们在不同状态下埋在沙土中的失稳临界载荷。结果表明,不同类型恐龙蛋在蛋窝中的不同排列方式是与其蛋壳的抗失稳能力的大小密切相关,是某些类群的恐龙在产卵时为解决其低强度蛋壳在保护卵不受外力损伤和在卵的孵化后期幼雏能够破壳而出这两方面的矛盾而采取的一种保护性措施。     

国内双歧杆菌制剂预防小儿继发性腹泻临床疗效的Meta分析

目的系统评价国内双歧杆菌制剂临床预防小儿继发性腹泻的效果。方法按照系统评价的要求检索CBMd isc、VIP、CNK I以及万方数据库等,获得18篇符合纳入标准的文献,共计患儿4050例,对其进行M eta分析,并评价M eta分析结果的稳定性和发表偏倚。结果异质性检验χ^2=34.60,P=0.007〈0.05,采用随机效应模型进行M eta分析,合并RR=0.41,95%C I为0.35～0.49,总体效应检验,Z=10.39,P〈0.00001,差异具有非常显著性,固定效应模型RR值和95%C I与随机效应模型完全一致,剔除小样本报道后的合并RR=0.42,95%C I为0.35～0.50,与剔除前的结果基本一致,且本研究的发表偏倚得到了很好地控制。结论从现有的临床证据来看,双歧杆菌制剂能降低小儿继发性腹泻的发生率,对预防小儿继发性腹泻起到了满意的效果。     

Role of Telomerase in Reactivation of Macrophage Nuclei in Heterokaryons

It was shown that the duration of stay of macrophages in the peritoneal cavity of mice and method of their isolation did not affect markedly their capacity for resumption of DNA synthesis in heterokaryons. This means that mouse macrophage undergo such changes during differentiation that reactivation of DNA synthesis in their nuclei is only possible after interaction of telomeres with telomerase, since it was already shown that telomerase was involved in reactivation of DNA synthesis in the macrophage nuclei. The results of experiments did not reveal differences in the length of telomeres in mouse macrophages and other somatic cells. This could depend on the significant length of mouse telomeres and, as a result, their shortening, sufficient for the inhibition of proliferation, is beyond the limits of sensitivity of the current methods. It is also possible that changes in DNA properties in the macrophages occurring during their differentiation depend on changes in the conformation of the telomere complex in these cells. Testing of this suggestion is relevant with respect to recent data that cell hybridization, specifically in the form of heterokaryons, may be essential in realization of the therapeutic effect caused by the introduction of cells during cell therapy.     

Studies of in vivo mutations in rpsL transgene in UVB-irradiated epidermis of XPA-deficient mice

We have established xeroderma pigmentosum group A (XPA) gene-knockout mice with nucleotide excision repair (NER) deficiency, which rapidly developed skin tumors when exposed to a low dose of chronic UV like XP-A patients, confirming that the NER process plays an important role in preventing UVB-induced skin cancer. To examine the in vivo mutation in the UVB-irradiated epidermis, we established XPA (−/−), (+/−) and (+/+) mice carrying the Escherichia coli rpsL transgene with which the mutation frequencies and spectra in the UVB-irradiated epidermal tissue can be examined conveniently. The XPA (−/−) mice showed a higher frequency of UVB-induced mutation in the rpsL transgene with a low dose (150 J/m²) of UVB-irradiation than the XPA (+/−) and (+/+) mice, while, at a high dose (900 J/m²) they showed almost the same frequency of mutation as the XPA (+/−) and (+/+) mice, probably because of cell death in the epidermis of the XPA (−/−) mice. However, CC→TT tandem transition, a hallmark of UV-induced mutation, was detected at higher frequency in the XPA (−/−) mice than the XPA (+/−) and (+/+) mice at both doses of UVB. This rpsL/XPA mouse system will be useful for further analyzing the role of NER in the mutagenesis and carcinogenesis induced by various carcinogens.     

Analysis of Spatial Distribution of Vesicles in Presynaptic Terminals of the Hippocampus in vivo and in vitro

A comparative morphometric analysis of electron photomicrographs of the presynaptic terminals in cultured in vitro for 7 days CA1 hippocampal slices from 7-day-old rats and in the hippocampi of 14-day-old rats was conducted. As compared with the terminals of intact neurons, the terminals of cultured cells were larger and contained a greater amount of synaptic vesicles, which, however, to a lesser extent were united in clusters. Distributions of the vesicle profiles in cultured slices were characterized by a greater distance to the nearest neighbor. Obviously, such structural features should be taken into account when interpreting data obtained in electrophysiological studies on hippocampal slice cultures.     

Comparison of the subcellular distribution of G-proteins in hepatocytes in situ and in primary cultures

The subcellular localization of the heterotrimeric G-proteins in hepatocytes in situ was compared to that in hepatocytes in primary culture. The ability of various ligands to activate adenylyl cyclase (AC) in membrane preparations was also investigated. In hepatocytes in situ the G proteins were mainly localized at the plasma membrane while in hepatocytes in culture they were predominantly cytoplasmic. The localization of the G-proteins in hepatocytes in situ correlates with their role in signal transduction. In homogenates prepared from the cultured cells, ligands which stimulate AC via G_sα were without effect, which was consistent with the localization of G_sα in the cytoplasmic and nuclear compartments. The “relocalization” of the G proteins to the cytoplasm when cells are cultured suggests that transmembrane signalling may be regulated by cell differentiation and cell-cell and cell-extracellular matrix interactions. © 1996 Wiley-Liss, Inc.     

Application of in silico and in vitro methods in the development of adverse outcome pathway constructs in wildlife

There is a long history of using both in silico and in vitro methods to predict adverse effects in humans and environmental species where toxicity data are lacking. Currently, there is a great deal of interest in applying these methods to the development of so-called ‘adverse outcome pathway’ (AOP) constructs. The AOP approach provides a framework for organizing information at the chemical and biological level, allowing evidence from both in silico and in vitro studies to be rationally combined to fill gaps in knowledge concerning toxicological events. Fundamental to this new paradigm is a greater understanding of the mechanisms of toxicity and, in particular, where these mechanisms may be conserved across taxa, such as between model animals and related wild species. This presents an opportunity to make predictions across diverse species, where empirical data are unlikely to become available as is the case for most species of wildlife.     

Transition of cancer in populations in India

Background & objectivesAn assessment of transition of cancer in India during the past 30 years, according to changes in demographic and epidemiologic risk factors was undertaken.Materials & methodsCancer registry data (http://www.ncdirindia.org), (population coverage <10%), was compared with transition in life-expectancy and prevalence on smoking, alcohol and obesity. We fitted linear regression to the natural logarithm of the estimated incidence rates of various cancer registries in India.ResultsBurden of cancer in India increased from 0.6 million in 1991 to 1.4 million in 2015. Among males, common cancers are lung (12.0%), mouth (11.4%), prostate (7.0%), and tongue (7.0%) and among females, they are breast (21.0%), cervix-uteri (12.1%), ovary (6.9%), and lung (4.9%) in 2012. Increased life-expectancy and population growth as well as increased use of alcohol and increased prevalence of overweight/obesity reflected an increase in all cancers in both genders except a reduction in infection-related cancers such as cervix-uteri and tobacco-related cancers such as pharynx (excludes nasopharynx) and oesophagus.Interpretation & conclusionTransition in demographics and epidemiologic risk factors, reflected an increase in all cancers in both genders except a reduction in a few cancers. The increasing incidence of cancer and its associated factors demands a planned approach to reduce its burden. The burden assessment needs to be strengthened by increasing the population coverage of cancer registries. Continued effort for tobacco prevention and public health efforts for reducing obesity and alcohol consumption are needed to reduce the cancer burden.     

Role of P-glycoprotein in tissue uptake of indinavir in rat

The effect of p-glycoprotein inhibition on tissue distribution of indinavir, an anti-HIV (human immunodeficiency virus) protease inhibitor drug, has been evaluated. Indinavir was co-administered intravenously in rats along with a p-glycoprotein inhibitor, PSC833, and the drug concentrations in plasma and various tissues were determined using a HPLC method. Additionally, initial uptake clearance of indinavir was evaluated in the brain and testes. The highest increasing effect of p-glycoprotein inhibition on the tissue uptake ratios of indinavir was found in central nervous system (CNS). The estimated tissue extraction the drug was indicative of (i) limited drug entry to brain parenchyma, which was increased significantly by p-glycoprotein inhibition, (ii) non-restricted drug entry to testes, heart and spleen, which was increased significantly in the case of heart and decreased in the case of testes and spleen as a result of p-glycoprotein inhibition, and (iii) drug accumulation in liver and small intestine and, to a lesser extent, kidney, which was not affected by p-glycoprotein inhibition. The uptake clearances of indinavir by brain parenchyma in PSC833-treated and control rats were 68.80+/-8.65 and 21.63+/-4.28 micro/min/g and the corresponding values for the testes were 39.84+/-4.90 and 36.65+/-2.54 microl/min/g. The difference was significant only in the case of brain parenchyma (P<0.001). These data showed that p-glycoprotein inhibition increases the CNS uptake of indinavir markedly and has some transient minor effects on drug uptake by some other tissues.     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义。综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望。     

猕猴桃茎尖超低温保存过程中超微结构观察

应用透射电镜观察了猕猴桃组培苗茎尖细胞在玻璃化法超低温保存过程中的超微结构变化.研究发现:在预培养、PVS2脱水处理过程中,茎尖细胞内液泡逐渐变多、变小,质壁分离愈加显著,表明细胞的抗冻力增强;在随后的冷冻和解冻过程中,部分细胞的质壁分离更加严重,细胞壁与细胞膜之间出现液腔,细胞器变得模糊,有些细胞的细胞膜、甚至细胞壁撕裂,细胞腔内留下破碎的细胞膜和细胞残片,细胞结构破坏严重,这可能是导致材料在恢复培养中死亡的原因之一;部分细胞经过7d的恢复培养后,细胞器清晰,细胞膜完好并紧贴细胞壁,细胞中央出现较大的液胞,具有与对照相似的结构特征,最终存活下来并能够再生植株.