Identification and in silico prediction of metabolites of tebufenozide derivatives by major human cytochrome P450 isoforms

Cytochrome P450 (CYP) enzymes constitute a superfamily of heme-containing monooxygenases. CYPs are involved in the metabolism of many chemicals such as drugs and agrochemicals. Therefore, examining the metabolic reactions by each CYP isoform is important to elucidate their substrate recognition mechanisms. The clarification of these mechanisms may be useful not only for the development of new drugs and agrochemicals, but also for risk assessment of chemicals. In our previous study, we identified the metabolites of tebufenozide, an insect growth regulator, formed by two human CYP isoforms: CYP3A4 and CYP2C19. The accessibility of each site of tebufenozide to the reaction center of CYP enzymes and the susceptibility of each hydrogen atom for metabolism by CYP enzymes were evaluated by a docking simulation and hydrogen atom abstraction energy estimation at the density functional theory level, respectively. In this study, the same in silico prediction method was applied to the metabolites of tebufenozide derivatives by major human CYPs (CYP1A2, 2C9, 2C19, 2D6, and 3A4). In addition, the production rate of the metabolites by CYP3A4 was quantitively analyzed by frequency based on docking simulation and hydrogen atom abstraction energy using the classical QSAR approach. Then, the obtained QSAR model was applied to predict the sites of metabolism and the metabolite production order by each CYP isoform.     

Island properties dominate species traits in determining plant colonizations in an archipelago system

The extrinsic determinants hypothesis emphasizes the essential role of environmental heterogeneity in species’ colonization. Consequently, high resident species diversity can increase community susceptibility to colonizations because good habitats may support more species that are functionally similar to colonizers. On the other hand, colonization success is also likely to depend on species traits. We tested the relative importance of environmental characteristics and species traits in determining colonization success using census data of 587 vascular plant species collected about 70 yr apart from 471 islands in the archipelago of SW Finland. More specifically, we explored potential new colonization as a function of island properties (e.g. location, area, habitat diversity, number of resident species per unit area), species traits (e.g. plant height, life-form, dispersal vector, Ellenberg indicator values, association with human impact), and species’ historical distributions (number of inhabited islands, nearest occurrence). Island properties and species’ historical distributions were more effective than plant traits in explaining colonization outcomes. Contrary to the extrinsic determinants hypothesis, colonization success was neither associated with resident species diversity nor habitat diversity per se, although colonization was lowest on sparsely vegetated islands. Our findings lead us to propose that while plant traits related to dispersal and establishment may enhance colonization, predictions of plant colonizations primarily require understanding of habitat properties and species’ historical distributions.     

Eucalypt leaf decomposition in an intermittent stream in south-eastern Australia

Eucalypt leaf packs were placed at two sites in an intermittent stream during summer to examine the hypothesis that terrestrially-exposed leaf litter accumulates a richer microbial flora than submerged leaves — a phenomenon observed in Canadian temporary vernal pools. This did not occur; during the experiment, microbial biomass (as ATP) rose steadily on submerged leaves but remained low on terrestrially-exposed leaves. Densities of most functional feeding groups on the submerged leaves increased with time. Scrapers appeared to be more important than shredders in eucalypt leaf breakdown at both sites.     

An hypothesis for the interpretation of the contractile response of vascular smooth muscle at the cellular level

The long preservation and recovery of functional (contractile) properties in cultured aortic smooth muscle cells, even after replating or deep-frozen storage and the measurement of their responses are now technically settled issues. We could thus study extensively the responses of single cultured cells from rat thoracic aorta. Responses were elicited by the addition of KCl 40 mmol/L without or with a calcium blocker PN 200-100 (10^–6 mol/L); angiostein II (10^–11–10^–6 mol/L) without or with antagonist (losartan 10^–5 mol/L); or serotonin (10^–9–10^–4 mol/L) without or with antagonist (naftidrofuryl 10^–5 mol/L). Results thus obtained enabled us to propose a new hypothesis for the interpretation of the contractile responses of an elastic vascular smooth muscle. The different maximal effects of different agonists result mainly from the different proportions of cells they can mobilize; the agonist concentration-contraction relationship is mainly due to the increase of the proportion of cells involved up to a maximal value typical of the agonist used. An antagonist primarily reduce the proportion of cells an agonist can mobilize. Some of the consequences of this hypothesis are briefly outlined.     

长江安庆新洲水域鱼类群落结构及多样性

沙洲水域环境良好,饵料资源丰富,栖息生境多样,为鱼类的生长繁殖提供了优良的生存环境。为了解长江安庆新洲水域鱼类群落结构特征,于2017年4月、7月、10月和12月对安庆江段新洲水域鱼类群落进行季节性调查。共采集鱼类64种,分属5目11科48属,其中62.5%为鲤科鱼类。以物种数和多样性指数分析群落多样性特征,结果表明新洲水域鱼类种类多样性水平较高。单因素方差分析表明,该群落多样性季节差异显著(P0.05),空间差异不明显。新洲水域鱼类群落优势种为鳊(Parabramis pekinensis Basilewsky, 1855)、鲤(Cyprinus carpio Linnaeus, 1758)、贝氏■(Hemiculter bleekeri Warpachowsky, 1887)、银鮈(Squalidus argentatus Sauvage et Dabry, 1874)和似鳊(Pseudobrama simoni Bleeker, 1864)。4种摄食功能群中,杂食性(42.19%)和肉食性(35.94%)鱼类物种数比例较高;3种生态类群中,淡水定居性鱼类占绝对优势(84.37%);3种栖息水层类型中,底层鱼类物种数比例较高,占37.50%。大型经济鱼类占总渔获物比例低(0.01%),但个体较大,因而相对重要性指数(IRI)高。总体上,新洲鱼类群落多样性和丰富度指数较高,均匀度指数偏低,个体小型化趋势明显。捕捞强度过大、水利工程建设导致的江湖阻隔及外来物种入侵是新洲水域渔业资源衰退的主要因素。由此,建议持续开展长江渔业资源监测,加强长江干流沙洲水域渔业资源保护。     

Stronger dung removal in forests compared with grassland is driven by trait composition and biomass of dung beetles

1. Ecosystem processes depend on the biomass of the involved organisms, but their functional diversity may play an additional role. In particular, the exclusion of key functional groups through habitat disturbance may lead to the breakdown of ecosystem functions. Dung removal is an important process contributing to nutrient cycling and thus productivity in grazed ecosystems. 2. This study investigated the role of different functional groups of dung beetles in dung removal in different habitats within a wood-pasture in two different seasons. An experimental setting with 12 blocks and 108 dung pads was used to investigate short-term dung removal over 1 week of exposure. 3. Dung removal was most strongly affected by habitat type, with almost 40% lower levels in grassland than in adjacent forest and forest gaps. Of all assemblage characteristics, total biomass of tunneller species was the strongest predictor of dung removal, whereas functional diversity showed no significant effect. In accordance with the dung removal pattern at habitat type level, densities of large tunnellers were suppressed in grassland compared with forest. 4. It is concluded that dung removal is habitat-specific and large tunnellers play a disproportionate role in this important ecosystem function in temperate forests.     

Neural Correlates of Body Integrity Dysphoria

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A global synthesis of the effects of diversified farming systems on arthropod diversity within fields and across agricultural landscapes

Agricultural intensification is a leading cause of global biodiversity loss, which can reduce the provisioning of ecosystem services in managed ecosystems. Organic farming and plant diversification are farm management schemes that may mitigate potential ecological harm by increasing species richness and boosting related ecosystem services to agroecosystems. What remains unclear is the extent to which farm management schemes affect biodiversity components other than species richness, and whether impacts differ across spatial scales and landscape contexts. Using a global metadataset, we quantified the effects of organic farming and plant diversification on abundance, local diversity (communities within fields), and regional diversity (communities across fields) of arthropod pollinators, predators, herbivores, and detritivores. Both organic farming and higher in‐field plant diversity enhanced arthropod abundance, particularly for rare taxa. This resulted in increased richness but decreased evenness. While these responses were stronger at local relative to regional scales, richness and abundance increased at both scales, and richness on farms embedded in complex relative to simple landscapes. Overall, both organic farming and in‐field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations. Our results suggest that organic farming and plant diversification promote diverse arthropod metacommunities that may provide temporal and spatial stability of ecosystem service provisioning. Conserving diverse plant and arthropod communities in farming systems therefore requires sustainable practices that operate both within fields and across landscapes.