Regulation of cell proliferation and cell death by peroxisome proliferators

Peroxisome proliferators cause increases in liver mass in rodents, linked to changes in cell proliferation and cell death of hepatocytes. These effects are reversible upon cessation of treatment. The underlying mechanism of the response in rodent liver is complex, but clearly dependent on activation of the nuclear receptor PPARalpha. Other signaling pathways have been implicated in this response, but evidence is mixed. Differing sensitivity among various species to effects of peroxisome proliferators has been associated with differences in PPARalpha expression and function. Changes in cell proliferation and cell death in neoplastic hepatocytes also have been found in liver tumors caused by long-term treatment with peroxisome proliferators.     

Application of automatic image analysis for quantitative morphological studies of peroxisomes in rat liver in conjunction with cytochemical staining with 3-3'-diaminobenzidine and immunocytochemistry.

We describe the application of automatic image analysis for quantitative morphological studies of peroxisomes in rat liver. For automatic detection by light and electron microscopy peroxisomes must be stained with the alkaline DAB procedure for catalase. There is a good agreement between the results obtained by conventional morphometric techniques and by automatic image analysis of DAB-stained electron microscopic preparations. Moreover, the image analyzer may be used in conjunction with a light microscope for evaluation of semithin sections (1-0.25 microns), provided the section thickness factor is taken into consideration. This latter approach has proven highly efficient in estimation of peroxisome proliferation. The limitations of this method and the relevance of volume density as a reliable morphometric parameter for evaluation of peroxisome proliferation are discussed. In the second part of this study we present the application of image analysis for quantitation of alterations of individual peroxisomal enzyme proteins after treatment with bezafibrate in immunogold stained ultrathin sections. There is good agreement between the results of quantitative immunocytochemistry and Western (immuno) blot analysis of highly purified peroxisomal fractions. In our experience quantitative immunoelectron microscopy provides a versatile, highly sensitive, and efficient method for detection of modulations of various proteins in peroxisomes. Finally the limitations and prospects of quantitative immunocytochemistry for investigation of peroxisomal proteins are discussed.     

Peroxisome biogenesis and degradation in yeast: a structure/function analysis

In yeast, peroxisomes are the site of specific catabolic pathways that characteristically include hydrogen peroxide producing oxidases and catalase. During the last 10 years, much progress has been made in unravelling the molecular mechanisms involved in the biogenesis of this organelle. At present, 23 different genes (PEX genes) have been identified that are involved in different aspects of peroxisome biogenesis (e.g., proliferation, formation of the peroxisomal membrane, import of matrix proteins). The principles of peroxisome degradation are still much less understood. Recently, the first yeast mutants affected in this process have become available and used to clone corresponding genes by functional complementation. In this paper, an overview is presented of the research on yeast peroxisomes, focusing on recent achievements in the molecular aspects of peroxisome development, function, and turnover.     

煤矿区地表土中烷基多环芳烃的定量方法研究

我国土壤中关于美国EPA优先控制的16种母体多环芳烃(16PAHs)的分析方法已较成熟且得到广泛应用,而针对烷基多环芳烃(a-PAHs)的测试和定量方法研究则较少.本研究建立了二氯甲烷超声萃取、净化,气相色谱-串联质谱法全扫描模式同时测定土壤中51种a-PAHs及16PAHs的方法.通过分析质量色谱图和质谱图,并结合N...     

表面活性剂结合QuEChERS-气相色谱-串联质谱法同时测定大豆油中有机氯农药、多氯联苯及多环芳烃

建立了气相色谱-串联质谱（GC-MS/MS）同时测定大豆油中34种有机氯农药（OCPs）、12种多氯联苯（PCBs）及6种多环芳烃（PAHs）残留量的检测方法。首先使用表面活性剂作为乳化剂制备相对稳定的油/水乳状液,采用乙腈-二甲苯（9∶1,V/V）为提取剂,以QuEChERS前处理方法对其提取2次后净化,随后进行GC-MS/MS检测。对8种表面活性剂及添加浓度进行优化,结果表明,表面活性剂的添加可显著提高大豆油中OCPs、PCBs及PAHs的提取率,最佳添加方案为大豆油∶水∶Tween60=1∶3∶0.01 （m/m/m）。该方法在1/2.5/5/10~400 μg/L浓度范围内的线性关系良好,相关系数R²为0.993 8~0.999 7。在5~100 μg/kg添加浓度水平内,相对标准偏差为1.59%~20.50%,34种OCPs在大豆油中的添加回收率为64.35%~120.63%,12种PCBs的添加回收率为49.65%~97.76%,6种PAHs的添加回收率为74.05%~101.52%。该方法操作简单、油脂去除效果良好,灵敏度、精密度及回收率均可满足国内外相关标准中大豆油中残留限量的要求。     

天然存在的碳、氮稳定同位素在生态系统研究中的应用

简要介绍稳定碳、氮同位素在生态系统领域中关于系统的碳源、能量流动、营养结构、污染物的生物放大作用 ,对系统稳定性变化的应用研究作了较为系统的论述 ,并对稳定碳、氮同位素在赤潮研究、环境污染治理、生态动力学建模及有机分子化合物系列示踪技术等方面的应用提出展望。     

气相色谱-串联质谱（GC-MS/MS）的应用研究进展

气相色谱-串联质谱（GC-MS/MS）依靠其高灵敏度和强抗干扰能力,在化学、生物和环境分析中已得到广泛的应用。通过文献调研确认了国内外GC-MS/MS应用研究最多的几个方向,简述了自2000年以来GC-MS/MS在农药残留、环境污染物（主要是多环芳烃、多氯联苯、多溴联苯醚和二噁英等）和类固醇激素等检测方面的应用。并对比分析了不同目标物,GC-MS/MS相对于其他仪器的优势以及应用于不同目标物时常用的前处理方法。对国内GC-MS/MS应用的基本方向进行了综述,并展望了其发展及应用前景。     

自然水体中多氯联苯分析方法及迁移转化

本文简要介绍多氯联苯的化学特性及毒性,综述水环境(地表水、沉积物和生物介质)中的多氯联苯的前处理方法以及分析方法的研究现状,以及多氯联苯在水环境(地表水、沉积物和生物介质)中的迁移转化及分布规律。     

水体中多环芳烃的前处理技术与分析方法

多环芳烃是一类痕量有机污染物,广泛存在于各种介质中且能持久存在,对环境造成很大危害,受到人们广泛的关注。本文介绍了近几年监测水体中痕量多环芳烃常使用的一些样品前处理方法和检测方法。     

Oxidative effects of the harmful algal blooms on primary organisms of the food web

Degraded water quality from nutrient pollution, physical, biological, and other chemical factors contributes to the development and persistence of many harmful algal blooms (HABs). The complex dynamics of the HABs is a challenge to marine ecosystems for the toxic effects reported. The consequences include fish, bird, and mammal mortality, respiratory or digestive tract problems, memory loss, seizures, lesions and skin irritation in many organisms. This review is intended to briefly summarize the recent reported information on harmful marine toxin deleterious effects over the primary organisms of the food web, namely algae, zooplankton and invertebrates. Special focus is made on oxidative stress status of cells and tissues. Even though in situ field research is less controlled than laboratory studies, in which the organisms are directly exposed to the toxins under consideration, both types of approaches are required to fully understand such a complex scenario. On top of that, the contribution of the increasing water temperatures in the sea, as a consequence of the global climate change, will be addressed as a topic for further studies, to evaluate the effect on regulating algal growth, species composition, trophic structure, metabolic stress and function of aquatic ecosystems.     

Human peroxisomal disorders

Peroxisomes are single membrane-bound cell organelles performing numerous metabolic functions. The present article aims to give an overview of our current knowledge about inherited peroxisomal disorders in which these organelles are lacking or one or more of their functions are impaired. They are multiorgan disorders and the nervous system is implicated in most. After a summary of the historical names and categories, each having distinct symptoms and prognosis, microscopic pathology is reviewed in detail. Data from the literature are added to experience in the authors' laboratory with 167 liver biopsy and autopsy samples from peroxisomal patients, and with a smaller number of chorion samples for prenatal diagnosis, adrenal-, kidney-, and brain samples. Various light and electron microscopic methods are used including enzyme- and immunocytochemistry, polarizing microscopy, and morphometry. Together with other laboratory investigations and clinical data, this approach continues to contribute to the diagnosis and further characterization of peroxisomal disorders, and the discovery of novel variants. When liver specimens are examined, three main groups including 9 novel variants (33 patients) are distinguished: (1) absence or (2) presence of peroxisomes, and (3) mosaic distribution of cells with and without peroxisomes (10 patients). Renal microcysts, polarizing trilamellar inclusions, and insoluble lipid in macrophages in liver, adrenal cortex, brain, and in interstitial cells of kidney are also valuable for classification. On a genetic basis, complementation of fibroblasts has classified peroxisome biogenesis disorders into 12 complementation groups. Peroxisome biogenesis genes (PEX), knock-out-mice, and induction of redundant genes are briefly reviewed, including some recent results with 4-phenylbutyrate. Finally, regulation of peroxisome expression during development and in cell cultures, and by physiological factors is discussed.     

Selective degradation of peroxisomes in yeasts

In the last two decades, much progress has been made in understanding the process of induction and biogenesis of peroxisomes, essential organelles in all eukaryotes. Only relatively recently, the first molecular studies on the selective degradation of this important organelle-a process known as pexophagy, which occurs when the organelles have become redundant-have been performed, especially using methylotrophic yeasts. The finding that pexophagy and other transport pathways to the vacuole (vacuolar protein sorting, autophagy, cytoplasm-to-vacuole-targeting and endocytosis) utilize common but also unique genes has placed pexophagy in the heart of the machinery that recycles cellular material. The quest is now on to understand how peroxisome degradation has become such a highly selective process and what the signals are that trigger it. In addition, because the prime determinant of pexophagy is located on the peroxisome itself, it has become essential to study the role of peroxisomal membrane proteins in the degradation process in detail. This review highlights the main achievements of the last years.     

辽宁省五城市大气可吸入颗粒物中多环芳烃污染特征研究

为全面了解辽宁省大气可吸入颗粒物污染状况,2004年在省内选取了5个城市进行分季节采样,并对颗粒物中美国优先控制的16种多环芳烃（PAHs）进行了定量研究。结果表明,大气PM10和PM2.5中PAHs污染较重,且冬季高于其它季节,PAHs主要富集在PM2.5及以下细小颗粒物中。     

开发新的电站风机应对节能减排新要求

分析了火电厂大气污染物排放新标准引发电站风机的运行参数和能耗的变化,并提出了一些电站风机开发需应对的策略和课题,可供风机行业参考。     

重金属对水生生物毒性作用研究进展

就目前重金属对水生生物毒性作用的研究进展做一综述。着重阐述重金属的来源、形态、理化特征、毒性机理和影响毒性大小的因素,以及对水生生物毒性作用做出较为全面的总结,并对该领域的研究方向做出预测和展望。     

流体系统用不锈钢管路的污染控制

流体系统的污染控制越来越引起业内人士的高度关注。尤其是随着流体系统向精密化、数字化、小型化的发展,以及伺服技术的应用,污染控制显得更为重要。作者以自己的工程实践,总结了流体系统常用的不锈钢管路污染控制和预防的经验,分析了不锈钢管路污染产生的各种因素,阐述了管路污染物检查的方法,以及管路污染防控的措施,以期对业界同仁在应用不锈钢管路中给予启示。     

DOAS在环境监测中的应用

差分光学吸收光谱技术(DOAS)近年来已成为环境监测中的可行方法。本文将该方法应用于大气污染监测,给出一套实用的DOAS系统,并通过一系列优化的数据处理流程和环节,可以成功地监测大气中多种气体成分的浓度。     

Gallium replication in aquatic and nonaquatic organism scanning electron microscopy.

A technique using pure gallium metal as a replication material is reported for biological surface scanning electron microscopy (SEM). The technique first directly enables aquatic organisms in water to be replicated due to gallium's low melting point and, second, reproduces surface structures and images of the two-dimensional (2D) distribution of substances transferred from the original surface to the gallium surface due to gallium's high surface tension. An aquatic protozoan in water was directly replicated to show its typical surface structures. The technique was then used to visualize human hair surface structures and 2D transferred substance distribution using X-ray microanalysis.     

土壤污染分析中样品采集与前处理方法探讨

土壤样品成分复杂，不同污染物需要采用不同的样品采集和前处理方法，本文重点对重金属、VOCs类、农药类、二恶英类和PCBs的前处理及测定方法进行了分析，比较了我国目前各种土壤消解方法的优、缺点，还介绍了日本现行的土壤前处理方法以及有关简易快速前处理和测定方法，以适应不同的环境管理的需求。