环境中类固醇激素与斑马鱼(Danio rerio)体内有机阴离子转运多肽(Oatp1d1)的相互作用

环境中类固醇激素具有很高的生物活性,在水环境中又普遍存在,因而对鱼类健康造成威胁。目前,对鱼体内类固醇激素的吸收过程和毒代动力学知之甚少,特别是其中细胞膜转运体的作用。我们考察了17种内源性和环境中类固醇激素与斑马鱼体内有机阴离子摄取性转运体Oatp1d1的相互作用,Oatp1d1在斑马鱼的肝脏和肾脏中有显著表达。我们选择了不同类别的类固醇激素,包括雄烯二酮(A4)、黄体酮(P4)及其代谢物、糖皮质激素和螺旋内酯甾酮(竞争性抑制萤光黄(Lucifer Yellow, LY)的吸收)。半数抑制效应浓度(IC₅₀)通过S形抑制曲线获得,P4的IC₅₀最小,其他IC₅₀由大到小排列为:17α-羟基黄体酮>丙酸氯倍他索>螺旋内酯甾酮>21-羟基黄体酮>醋酸氟氢可的松和其他的糖皮质激素。类固醇激素的亲脂性与Oatp1d1相互作用的活性呈正相关关系。我们的数据表明不同类别的类固醇激素与Oatp1d1的相互作用活性不同,或为吸收,或为抑制,或吸收和抑制。如此可知类固醇激素会介入内源性底物的转运过程,以致相关的生理过程。同时,类固醇激素可通过竞争性抑制作用改变环境污染物的细胞贩运。 精选自Raffael Alois Willi, Karl Fent. Interaction of environmental steroids with organic anion transporting polypeptide (Oatp1d1) in zebrafish (Danio rerio). Environmental Toxicology and Chemistry,2018,37:2670-2676.
详情请见 https://doi.org/10.1002/etc.4231
     

Hopanoid Biosynthesis and Function in Bacteria

   Hopanoids are pentacyclic triterpenoid lipids occurring in bacteria. They are synthesized from isopentenyl units which are formed in a new biosynthetic route leading to isopentenyl diphosphate. Six C₅ units are joined to form squalene, the immediate precursor in hopanoid synthesis. In a highly complex cyclization reaction that shares considerable similarities with that of oxidosqualene to sterols, the hopane skeleton is formed from squalene by the squalene-hopene cyclase. Recent elucidation of the X-ray structure of this membrane-bound cyclase has shed some light on the properties of this unusual enzyme. The active site is located in a cavity within the enzyme. The squalene substrate diffuses through a channel structure from the membrane into this cavity and is there transformed into hopene. Polar side chains are attached to hopene resulting in the amphiphilic molecular structure of many hopanoids. These hopanoids are membrane components involved in regulating membrane fluidity and stability. However, the many structural variants of hopanoids indicate that they may have other interesting but as yet unknown functions.     

Heavy metal contents in whitefish (Coregonus lavaretus) along a pollution gradient in a subarctic watercourse

Metallurgic industry is a source of serious environmental pollution related to the emission of heavy metals. Freshwater systems are focal points for pollution, acting as sinks for contaminants that may end up in fish and humans. The Pasvik watercourse in the border area between Finland, Norway and Russia is located in the vicinity of the Pechenganickel metallurgic enterprises, and the lower part of the watershed drains the Nikel smelters directly through Lake Kuetsjarvi. Heavy metal (Ni, Cu, Cd, Zn, Pb and Hg) concentrations in environment (water and sediments) and whitefish Coregonus lavaretus tissue (gills, liver, kidney and muscle) were contrasted between five lake localities situated along a spatial gradient of increasing distance (5-100 km) to the smelters. The heavy metal concentrations, in particular Ni, Cu and Cd, were highly elevated in Kuetsjarvi, but steeply declined with increasing distance to the smelters and were moderate or low in the other four localities. The study demonstrates that the majority of metal emissions and runoffs are deposited near the pollution source, and only moderate amounts of the heavy metal contaminants seem to be transported at further distances. Bioaccumulation of Hg occurred in all investigated tissues, and higher Hg concentrations in planktivorous versus benthivorous whitefish furthermore indicated that pelagic foraging is associated with higher levels of Hg biomagnification. Potential population ecology impacts of high heavy metal contaminations where mainly observed in whitefish in Kuetsjarvi, which showed depletions in growth rate, condition factor and size and age at maturation.     

Substance-related environmental monitoring

Background  Due to the requirements of the EU Water Framework Directive and other legal regulations (e.g., national laws like the German Federal Soil Protection Act), but also due to the implementation of the new EU chemicals management system REACH, environmental monitoring will gain increasing importance for the surveillance of environmental quality as well as for the assessment of chemicals. Against this background, the Work Group on ‘Environmental Monitoring’ of the Division of ‘Environmental Chemistry and Ecotoxicology’ within the German Chemical Society has compiled a position paper on substance-related environmental monitoring. Scope  Core elements of this position paper are the definitions of important terms like monitoring, exposure monitoring, effect monitoring, and integrated monitoring. Moreover, temporal and spatial aspects (monitoring of spatial distributions, trend monitoring, and retrospective monitoring) and their applications are discussed. The main focus of this position paper is the coverage of aspects which have to be observed for the preparation and implementation of a monitoring program. Essential is the clear specification of the targets of the monitoring which determine the development of the monitoring concept and its realization, e.g., if environmental media (compartments) or organisms are most appropriate as samples for the aim of the study. Of course, also the properties of the target substances are important (e.g., lipophilicity/bioaccumulation as pre-requisite for an exposure monitoring with organisms). Finally, the monitoring phases of sample planning, sampling, storage and transport of samples, selection of analytical methods, quality assurance measures as well as reporting are discussed. Perspectives  An important issue for the future is to link the quantification of chemicals in environmental compartments (exposure and pollution monitoring) more closely to the study of biological effects (effect monitoring) than has been the case up to now. Furthermore, by inclusion of a spatial differentiation, a comprehensive evaluation of the state of an ecosystem can be obtained and the relevance of the results improved. Practical examples of monitoring studies which illustrate various aspects covered in this position paper will be presented in a series of publications by members of the Work Group in the following issues of this journal.

Synthesis of polyhydroxyalkanoates in municipal wastewater treatment.

Biologically derived polyesters known as polyhydroxyalkanoates (PHAs) represent a potentially "sustainable" replacement to fossil-fuel-based thermoplastics. However, current commercial practices that produce PHA with pure microbial cultures grown on renewable, but refined, feedstocks (i.e., glucose) under sterile conditions do not represent a sustainable commodity. Here, we report on PHA production with a mixed microbial consortium indigenous to an activated sludge process on carbon present in municipal wastewaters. Reactors operated under anaerobic/aerobic and aerobic-only mode and fed primary solids fermenter liquor maintained a mixed microbial consortium capable of synthesizing PHA at 10 to 25% (w/w), while reducing soluble COD by approximately 62 to 71%. More critically, an aerobic batch reactor seeded from the anaerobic/aerobic reactor and fed fermenter liquor achieved approximately 53% PHA (w/w). Results presented suggest that environmentally benign production of biodegradable polymers is feasible. We further used PHA-rich biomass to produce a natural fiber-reinforced thermoplastic composite that can be used to offset advanced wastewater treatment costs.