施肥深度对矮化苹果15N尿素吸收、利用及损失的影响

以5年生烟富3/M26/平邑甜茶为试材,采用¹⁵N同位素示踪技术,研究表层(0 cm)、上层(20 cm)和中层(40 cm)3个施肥深度对矮化苹果¹⁵N 尿素吸收、分配及利用特性的影响.结果表明： 20 cm施肥处理的叶面积、叶绿素含量和叶片全氮含量显著高于0和40 cm施肥处理.不同施肥处理各器官从肥料中吸收分配到的¹⁵N量对该器官全氮量的贡献率(Ndff)存在显著差异,盛花期均以根的Ndff最高,多年生枝次之;新梢旺长期和花芽分化期根部吸收的¹⁵N优先向新生营养器官转运;果实膨大期各器官Ndff均达到较高水平;果实成熟期均以果实中的Ndff最高.果实成熟期不同施肥处理的¹⁵N分配率存在显著差异,20 cm施肥处理生殖器官和营养器官的¹⁵N分配率显著高于0和40 cm施肥处理,而贮藏器官的¹⁵N分配率显著低于0和40 cm施肥处理.在果实成熟期,20 cm施肥处理¹⁵N肥料利用率为24.0%,显著高于0 cm(14.1%)和40 cm施肥处理(7.6%),而¹⁵N损失率为54.0%,显著低于0 cm(67.8%)和40 cm施肥处理(63.5%).不同施肥深度土壤¹⁵N残留量随施肥深度的增加而显著增加.     

农田氮肥利用率计算方法研究进展

氮肥利用率是农学和环境科学等领域普遍关注的焦点,合理计算氮肥利用率是实现农田氮素优化管理的重要前提和基础. 近年来,鉴于我国农田氮肥利用率测定值偏低,且存在很大变幅的事实,国内学者针对传统氮肥利用率的概念和计算方法进行了深入的思考和探讨,并提出了一些改进的尝试. 本文首先综述了传统氮肥利用率在概念和计算方法上存在的种种缺陷,然后较为系统地介绍了目前学者提出的计算农田氮肥利用率的几种常见的替代方法,并对今后的研究方向进行了展望.建议在正确理解氮肥用量、作物产量、氮肥利用和损失之间辩证关系的基础上,逐步建立起符合现阶段我国农业生产现状的农田氮肥利用状况评价体系.     

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。     

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.     

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。     

右美托咪啶用于SICU镇静时血流动力学效应与年龄的关系

目的：以心率（HR）、心指数（CI）、体循环阻力（SVR）作为效应指标,明确右美托咪啶（Dex）用于SICU 镇静时年龄和血流动 力学效应的关系。方法：选择2014 年3 月~7 月间在我院SICU 接受普胸或者普外科手术后需要短期镇静患者38 例,各年龄段分 布相对均匀。在病人术后Ramsay评分≤ 3 分时给予右旋美托咪啶6.0 ug/kg/h,连续静脉输注10 min 后停药,应用脉搏指示连续 心输出量监测技术(PICCO)记录用药前及用药后3 min、5 min、8 min、10 min、15 min、20 min、30 min、45 min、60 min、90 min、120 min 的11 个时间点的HR、CI 和SVR。结果：HR、CI 和SVR 的EMAX 随着年龄的增加而增大,可以通过数学模型表示：E= （P<0.05）。结论：右美托咪啶用于SICU 镇静时,患者HR、CI和SVR的EMAX 呈 年龄依赖性变化。     

我国蝴蝶产业发展中亟待解决的几个问题

本文简略介绍了我国目前蝴蝶产业的背景情况和发展现状,着重阐述了该产业发展中亟待解决的目标与思路、政策与法律、科研与技术、人才与培养等一系列问题,并针地性提出了相应解决意见。     

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.     

细胞分裂素对植物衰老的延缓作用

细胞分裂素是一类重要的植物激素,它可在一定程度上延缓植物的衰老。主要从3个方面综述了细胞分裂素与植物衰老之间的关系,即:(1)植物衰老过程中内源细胞分裂素含量变化;(2)外源细胞分裂素的影响;(3)转入与细胞分裂素的合成、降解相关的基因对植物衰老产生的影响。此外,还从细胞分裂素与糖、与脂质氧化反应以及与其它植物激素的关系方面探讨了细胞分裂素在延缓植物衰老中的作用机理。     

Application of in vitro techniques in mutation breeding of chrysanthemum

Rooted cuttings of Chrysanthemum morifolium cv. Maghi, a small flowered, late blooming cultivar, were treated with different doses of gamma rays. Somatic mutations in flower colour (light mauve, white, light yellow and dark yellow) and chlorophyll variegation in leaves were detected as chimeras in treated populations. Attempts were made to standardize a microtechnique for plant regeneration from mutated tissues of stem node, stem internode, shoot tip and ray floret. All these explants were cultured on Murashige and Skoog's medium with 3% sucrose, 0.8% agar and different concentrations and combinations of growth regulators. Plant regeneration was successful from all of the mutated tissues. Plants with chlorophyll variegation in leaves and two new flower colours (light mauve and white) were isolated in pure form with 64% and 100% efficiency of mutant recovery, respectively. Attempts are being made to use this technique to establish new varieties from chimeric tissues to meet the increasing demand of the floriculture trade.     

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.     

Presence of rhizobia in soils in Somalia

Bradyrhizobium japonicum was absent and only low numbers of Rhizobium were present in nodulating forage legumes in 13 soil samples from the Jubba and Shabelle rivers of Somalia.The authors are with the Dipartimento di Biologia Vegetale Sez, Microbiologia Applicata, Università degli Studi di Perugia, via Borgo XX Giugno 74, 06100 Perugia, Italy     

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.     

Role of Hrs in maturation of autophagosomes in mammalian cells

Autophagy is an evolutionarily conserved system responsible for the degradation of cellular components and contributes to the increasing of amino acid pool, organelle turnover, and elimination of intracellular bacteria. The molecular process of autophagy is still unclear. Here we demonstrate that Hrs, a master regulator in endosomal protein sorting, plays critical roles for the autophagic degradation of non-specific proteins and Streptococcus pyogenes. We found that Hrs containing FYVE domain is localized to autophagosomes. Hrs depletion resulted in a significant decrease in the number of mature autophagosomes (autophagolysosomes) detected by the co-localization of autophagosome marker LC3 and lysosome marker LAMP-1. In contrast, formation of the primary autophagosome, detected by LC3 immunoblotting and lysosomal degradation of non-specific proteins, were not significantly altered by Hrs depletion. Based on these results, we propose a novel function of Hrs, as a crucial player in the maturation of autophagosomes.     

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.