Attenuation of glyceraldehyde-3-phosphate dehydrogenase activity and ATP levels in rat brain synaptosomes by acrylamide

The effect of neurotoxin acrylamide (AC) on energy metabolism has been studied in a purified preparation of the synaptosomes. The synaptosomes were prepared by the flotation technique in a discontinuous Ficoll/sucrose gradient. The purity of the synaptosomes was checked by electron microscopy and by assaying the activity of marker enzymes. By these criterias, free mitochondrial contamination in the synaptosomes was found to be >2%. Incubation of the synaptosomes with different concentrations of AC (2.5, 5.0, and 10mM) produced a concentration-dependent inhibition (15, 35, and 60%, respectively) of glyceraldehyde-3-phosphate dehydrogenase activity. Acrylamide also produced a time-dependent decrease of ATP concentrations in the synaptosomes; about 25% loss of ATP was seen within 1h, while about 60% ATP was lost after 120 min incubation with 10 mM AC. The effect of known inhibitors of glycolysis-iodoacetic acid (IAA), and of oxidative phophorylation-rotenone and antimycin A, was also studied on ATP synthesis by the synaptosomes. IAA was found to be the most potent inhibitor of ATP synthesis, while both rotenone and antimycin A were equally effective in blocking ATP synthesis in the synaptosomes. These studies show that the synaptosome might be used as a suitablein vitro model to study the effect of neurotoxin such as AC on neuronal energy metabolism.Special issue dedicated to Dr. Sidney Ochs.     

Sequential reactors for the removal of endocrine disrupting chemicals by laccase immobilized onto fumed silica microparticles

Abstract

The main objective of this study is the evaluation of the capability of laccase from Myceliophthora thermophila immobilized on fumed silica microparticles (fsMP) for the removal of endocrine disrupting chemicals (EDCs) in two enzymatic reactor configurations. This type of support can also be magnetized to allow the straightforward separation of the biocatalyst under a magnetic field. The support exhibited excellent biocompatibility with the enzyme, superior tolerance to pH and temperature as well as improved stability in comparison with the free enzyme, even in the presence of organic solvents and enzyme inhibitors. The technical feasibility of the removal of EDCs by immobilized laccase was assessed in two types of enzymatic reactors operated in sequential mode: a membrane reactor using fsMP-laccase and a reactor with magnetic separation using magnetized fsMP-laccase. The extent of transformation for the target compounds: bisphenol A (BPA) and 17β-estradiol (E2) was high and comparable to free laccase in both systems (up to 80%). The possibility of reusing the immobilized enzyme, especially for magnetized supports, offers an interesting approach in the development of enzyme based processes for the biotransformation of emerging pollutants.     

Nitrogen's Role in Industrial Systems

Nitrogen is one of the key component elements in biological systems, but it also plays an increasingly important part in other areas of a modern industrial system. The starting point for almost all nitrogen-based chemicals is ammonia. This article presents 1996 production and use statistics for ammonia and its most important derivatives. We also characterize the key production processes and emissions. Finally, we summarize losses and emissions of nitrogen within the sector.     

Enantiotopic Selectivity of-Pig Liver Esterase Isoenzymes

Pig liver esterase was separated into isoenzyme fractions with known subunit compositions. The fractions showed differences in enantiotopic ester group selectivity in hydrolysis of two substrates of synthetic value, benzylmethylpropanedioic acid dimethyl ester and cis-N-benzyl-2,5-bismethoxy-carbonylpyrrolidine. A difference in aliphatic chain length specificity between the isoenzyme fractions was also observed. The results indicate that pig liver esterase cannot be regarded as homogeneous when used in organic synthesis.     

Contamination of Paddy Soil by Endocrine-Disrupting Chemicals Affects Soil Microbe Abundance and Diversity

We describe the effect on the population of Eubacteria and Archaea species of adding the endocrine-disrupting chemicals (EDCs) nonylphenol (NP) or dibutylphthalate (DBP) to a typical paddy soil. Fluorescence in-situ hybridization was used to discriminate between the two phyla, and denaturing gradient gel electrophoresis (DGGE) of an amplified fragment of the 16S rRNA locus was used to profile the species present. The population of both Eubacteria and Archaea species was reduced by the presence of NP or DBP, and the deleterious effect was greater for the Eubacteria. The DGGE profiles were used to assess the species diversity in the polluted and non-polluted soil samples. This showed that DBP was less damaging than NP₅₀. It was clear that EDCs can significantly affect paddy soil microbial diversity, both with respect to population size and species representation.     

Assessing the exposure risk and impacts of pharmaceuticals in the environment on individuals and ecosystems

The use of human and veterinary pharmaceuticals is increasing. Over the past decade, there has been a proliferation of research into potential environmental impacts of pharmaceuticals in the environment. A Royal Society-supported seminar brought together experts from diverse scientific fields to discuss the risks posed by pharmaceuticals to wildlife. Recent analytical advances have revealed that pharmaceuticals are entering habitats via water, sewage, manure and animal carcases, and dispersing through food chains. Pharmaceuticals are designed to alter physiology at low doses and so can be particularly potent contaminants. The near extinction of Asian vultures following exposure to diclofenac is the key example where exposure to a pharmaceutical caused a population-level impact on non-target wildlife. However, more subtle changes to behaviour and physiology are rarely studied and poorly understood. Grand challenges for the future include developing more realistic exposure assessments for wildlife, assessing the impacts of mixtures of pharmaceuticals in combination with other environmental stressors and estimating the risks from pharmaceutical manufacturing and usage in developing countries. We concluded that an integration of diverse approaches is required to predict ‘unexpected’ risks; specifically, ecologically relevant, often long-term and non-lethal, consequences of pharmaceuticals in the environment for wildlife and ecosystems.     

二恶英反应增强子调控的虫荧光素酶报告基因质粒的构建

为加强二恶英类化学物质的快速筛选和半定量检测,我们构建了一在二恶英反应增强子调控下的虫荧光素酶报告基因质粒。二恶英反应增强子来源于pHAV质粒,MMTV启动子来源于pCatM质粒,上述两者连接后与虫荧光素酶载体连接,转染人HepG2肝癌细胞,以2,3,7,8四氯代二苯并二恶英(TCDD)诱导报告基因表达后检测虫荧光素酶活性。结果表明该质粒中虫荧光素酶的表达受二恶英反应增强子的调控,且在一定浓度范围内虫荧光素酶的活性与TCDD的量呈线性关系。研究显示该质粒转染的细胞株有望用于快速筛选及半定量检测二恶英,可进一步加强研究作为二恶英类化学物质监测的常规方法。     

中链化学品微生物制造

中链脂肪酸（C₆-C₁₂）衍生的化学品包括脂肪醇、脂肪烃、中链酯、ω-修饰脂肪酸等,这些化合物是生物燃料、聚合物、日用化学品、特种化学品的重要组分。天然微生物底盘不能合成中链脂肪酸,而通过操纵脂肪酸合成、逆β-氧化等碳链延伸途径,尤其是表达生成游离中链脂肪酸的硫酯酶,可使大肠埃希菌、酿酒酵母等微生物细胞合成超过1 g/L的中链脂肪酸。引入脂肪酸衍生反应,如羧基还原、脱羧、ω-氧化等,可合成许多中链化学品。本文综述了中链化学品合成的酶学基础以及代谢工程策略,为中链化学品高效生物制造提供参考和思路。     

基于文献计量的全球生物技术研究现状与发展趋势分析

采用文献计量分析方法,分析了全球生物技术研究领域的发展现状和趋势及其对中国生物技术研究发展的启示。研究结果表明:2019年我国在生物技术文献发表数量上已位列世界第一,但在生物技术文献的质量、学术影响力以及国际合作能力方面仍与欧美等发达生物技术国家存在一定差距,接着分析了全球生物技术研究的学科组成、各生物技术分支领域的研究交叉现状,最后分析了目前各生物技术细分领域的热点研究主题。针对当前我国面临的生物技术研究发展问题,我国应当注重研究成果质量,促进各学科间交叉融合,加强国际合作交流,顺应未来生物技术发展热点趋势。