Evaluation of relative importance of different microbial reactions on organic matter removal in horizontal subsurface-flow constructed wetlands using a 2D simulation model

In this study, we used a two-dimensional (2D) mechanistic mathematical model in order to evaluate the relative contribution of different microbial reactions to organic matter removal (in terms of COD) in horizontal subsurface-flow constructed wetlands that treated urban wastewater. We also used the model to analyse the effect of increasing or decreasing the organic loading rate (changing the hydraulic loading rate (HLR) at a constant influent organic matter concentration, or changing the organic matter concentration at a constant HLR) on both the removal efficiency and the relative importance of the microbial reactions. The model is based on the code RetrasoCodeBright, which we modified to include the main microbial processes related to organic matter and nitrogen transformations in the wetlands: hydrolysis, aerobic respiration, nitrification, denitrification, sulphate reduction and methanogenesis. The model was calibrated and validated with data from two wetlands (each with a surface area of 55 m²) located in a pilot plant near Barcelona (Spain). According to the simulations, anaerobic processes (methanogenesis and sulphate reduction) are more widespread in the wetlands and contribute to a higher COD removal rate (60–70%) than anoxic (denitrification) and aerobic reactions do. These model results are confirmed by experimental observations. In all the cases tested, the reaction that most contributed to COD removal was methanogenesis (33–52%). According to our simulations, decreasing the HLR (for example, from 40 to 25 mm/d) while maintaining a constant COD influent concentration has a clear positive impact on COD removal efficiency (which increases from 65% to 89%). Changing influent COD concentration (for example, from 290 to 190 mg/L) while maintaining a constant HLR has a smaller impact, causing efficiency to increase from 79% to 84%. Changes in influent COD concentration (at a constant HLR) affect the relative contribution of the microbial reactions to organic matter removal. However, this trend is not seen when the HLR changes and the COD influent concentration remains constant.     

RT—PCR法检测我国东南沿海凡纳滨对虾的桃拉综合征病毒

桃拉综合征病毒（Taura syndrome virus,TSV）引致养殖及野生对虾急性传染病,14d至40d的幼虾极易感。该病毒属微RNA病毒科（Picornaviridae）,近年来研究者认为应归类为类蟋蟀麻痹病毒属（Cricket paralysis—like viruses）,因其基因组特征更接近于前所未分类的昆虫单股RNA病毒,如丙型果蝇病毒。     

苏云金杆菌4.0718菌株杀虫晶体65kD原毒素的质谱分析

以苏云金杆菌4.0718菌株杀虫晶体65kD原毒素为材料,探索了从SDS－PAGE胶上回收蛋白质进行质谱分析的方法。蛋白纯化的步骤包括SDS－PAGE、电洗脱、脱盐、除SDS。电洗脱采用半透膜法,用超滤法脱盐,冷丙酮沉淀法除去SDS。结果表明,纯化的65kD原毒素经ESI－MS检测,分子量约64500Da。经MALDI－MS检测,未能有明显蛋白峰出现,这可能是该蛋白由于较强的疏水作用,溶解性差,在与基质混合时处于聚和悬浮态所致。     

Nmi及其变异体在大肠杆菌中表达、抗体制备及其细胞分布

 为了检测细胞内源性Nmi和变异体Nmi s的表达、亚细胞分布以及可能形成的信号转导蛋白复合物 ,成功构建并表达了异源Nmi和Nmi s 获得纯化异源蛋白 ,用以制备兔源抗Nmi(Nmi s)多克隆抗体 .Western印迹在多种细胞株HL 60 ,K562 ,2 93T细胞中检测到Nmi(Nmi s)高表达 .在不同的细胞系中 ,Nmi表现为不同的蛋白复合物迁移带 ;Nmi(Nmi s)在胞浆和胞核均存在 ,而核内荧光更强 .Nmi(Nmi s)通过与多种蛋白相互作用行使其生物学功能 ,在不同细胞中可能与不同的蛋白相互作用 ,发挥不同的功能 .     

古井老枞茶树生态系统中细菌与真菌群落多样性特征分析

【目的】古井老枞经过漫长生长形成了独特“枞味”,而山场是茶叶品质形成的重要因素,微生物在山场生态系统的生物地球化学循环过程中可能起着关键作用,但老枞生态系统微生物群落组成特征还尚未明确。【方法】以生长于武夷山国家公园慧苑坑古井区域的老枞茶树为研究对象,采集茶树地上部叶片(叶际和叶内)和地下部土壤(根际、非根际和非茶园种植区空白),分别以细菌16S rRNA基因和真菌内部转录间隔区(internal transcribed spacer, ITS)基因为分子标记,采用高通量测序技术分析其细菌和真菌群落组成特征。【结果】老枞茶树地上部细菌和真菌群落丰富度和多样性皆显著低于地下部。共现性网络中,各生态位网络的模块化指数均超过0.4,且微生物物种之间的协同作用大于竞争。门水平,变形菌(Proteobacteria)、酸杆菌(Acidobacteriota)、放线菌(Actinobacteriota)、子囊菌(Ascomycota)和担子菌(Basidiomycota)皆为地上和地下共有优势菌门(相对丰度>1%),地上部变形菌、放线菌和子囊菌含量高于地下部,而酸杆菌和担子菌则相反(P<...     

广西猕猴桃三个新变种

报道了广西猕猴桃属植物的三个新变种。     

木霉属真菌的系统学及其应用研究

介绍了木霉属真菌的分类系统 ,有关木霉种系发育的分子生物学研究进展 ,以及在酶制剂、农业和环境保护中的应用概况。     

Biodiversity in South African fynbos and Mediterranean heathland

Abstract. The theory of convergence predicts that, given similar selective regimes, both present and past, unrelated ecological communities will show similar attributes. Mild Pleistocene climate, highly infertile soils, and similar fire regimes explain the remarkable convergence between mediterranean‐type vegetation from South Africa (fynbos) and Australia (kwongan). Heathlands in the Aljibe Mountains, at the western end of the Mediterranean basin, constitute a single vegetation type within the Mediterranean region. We studied the association between endemism and plant life form in a flora from environmentally similar areas of the South African Cape region (fynbos) and the Aljibe Mountains by contingency table analysis. We included two non‐acid, neighbouring areas to the latter region in the analysis as contrasts. We also compared the patterns of variation in three components of biodiversity (species richness, endemism level and taxonomic singularity) of fynbos and Aljibe heathland woody plant communities along similar soil fertility gradients by means of two‐way ANOVAs. At the regional (flora) level, our results show two common features in the biological aspects of endemism between the two regions: (1) edaphic endemism and (2) association of endemism with the shrub growth form. At the community level, we detected strong similarities in the patterns of variation of endemism and taxonomic singularity of woody communities from both regions along an ecological gradient related to soil fertility. We interpret these similarities, both at the regional and community levels, as suggestive of convergence between fynbos and Aljibe heathland.     

The Influence of Auxin and Cytokinin on Proliferation and Morphology of Somatic Embryos of Picea abies (L.) Karst

Embryogenic cell-lines of Picea abies were initiated from maturezygotic embryos and cultured on medium containing 2,4-D andBA The cell-lines were categorized into two main groups (solar/polarand undeveloped embryos), based on the morphology of the somaticembryos and their ability to go through a maturation processwhen treated with ABA The cell-lines were transferred to mediacontaining (1) 2,4-D and BA, (2) only BA, (3) only 2,4-D or(4) no growth regulators When cultured on a medium containingboth 2,4-D and BA new somatic embryos were continually formedIn contrast, when they were cultured without one or both ofthe growth regulators no new somatic embryos were formed Solar/polarand undeveloped embryos responded in the same way On a mediumcontaining only BA the somatic embryos already present increasedin size and developed an extremely large embryonic region Ona medium containing only 2,4-D the embryos already present becamedisorganized into loose aggregates When transferred from a mediumcontaining both 2,4-D and BA to one containing ABA, mature somaticembryos developed from the solar/polar type but not from theundeveloped type The ability of the solar/polar somatic embryosto go through a maturation process decreased when they wereprecultured on a medium lacking auxin and was lost when theywere precultured on medium lacking cytokinin The cell-linescontaining undeveloped somatic embryos produced mature somaticembryos in one cell-line out of three that had been culturedon the medium containing only BA Auxin, cytokinin, embryogenic cultures, Norway spruce, somatic embryos, Picea abies (L.) Karst     

A New and Simple Method for Studying the Microanatomy of Nephrons and Collecting Tubules

A simple procedure for studying the microanatomy of the kidney by light microscopy is described. Specimens are dried by the critical-point method and later impregnated with a mounting medium. The retention of air within the lumen of nephrons and collecting tubules permits their visualization. The method allows the observation of renal microanatomy without the distortions produced by microdissection or the loss of structural relationships among different kidney components. It also permits observation of the same specimen by both light and scanning electron microscopy.