Acarbose improved survival for Apc+/Min mice

Acarbose blocks the digestion of complex carbohydrates, and the NIA Intervention Testing Program (ITP) found that it improved survival when fed to mice. Yet, we do not know if lifespan extension was caused by its effect on metabolism with regard to the soma or cancer suppression. Cancer caused death for ~80% of ITP mice. The ITP found rapamycin, an inhibitor to the pro‐growth mTORC1 (mechanistic target of rapamycin complex 1) pathway, improved survival and it suppressed tumors in Apc^+/Min mice providing a plausible rationale to ask if acarbose had a similar effect. Apc^+/Min is a mouse model prone to intestinal polyposis and a mimic of familial adenomatous polyposis in people. Polyp‐associated anemia contributed to their death. To address this knowledge gap, we fed two doses of acarbose to Apc^+/Min mice. Acarbose improved median survival at both doses. A cross‐sectional analysis was performed next. At both doses, ACA fed mice exhibited reduced intestinal crypt depth, weight loss despite increased food consumption and reduced postprandial blood glucose and plasma insulin, indicative of improved insulin sensitivity. Dose‐independent and dose‐dependent compensatory liver responses were observed for AMPK and mTORC1 activities, respectively. Only mice fed the high dose diet exhibited reductions in tumor number with higher hematocrits. Because low‐dose acarbose improved lifespan but failed to reduced tumors, its effects seem to be independent of cancer. These data implicate the importance of improved carbohydrate metabolism on survival.     

Spatial distribution and environmental risk assessment of heavy metals identified in soil of a decommissioned uranium mining area

Abstract

The spatial distribution of six heavy metals (Cd, As, Zn, Pb, Cr, and Cu) in the soil of a decommissioned uranium mining area was investigated and their potential environmental risk was assessed. Soil samples were collected along the main riversides enclosing the mining area. The heavy metal distribution was determined by geospatial interpolation. Pearson correlation coefficient and principal component analysis were used to locate the sources of pollution which are the mine ore as natural source, and dressing plants and tailing area from human activity. The results indicate that the average concentrations of As and Cd strongly exceed the recommended EQSS (Environmental Quality Standard for Soils of China) limits at all sampling sites, whereas Zn concentrations were found to be slightly over the limit only at sampling sites close to the mining area. The concentrations of Cr, Cu and Pb were all within the recommended limits. Environmental risk was assessed using the toxicity characteristic leaching procedure defining the degree to which extend the metal is released into the solution. High leaching rates were found only for Zn and Cd, suggesting that together with its high concentrations Cd is the most toxic metal around the mining area, followed by As.     

An anti-inflammatory isoflavone from soybean inoculated with a marine fungus Aspergillus terreus C23-3

ABSTRACT

A new isoflavone derivative compound 1 (psoralenone) was isolated from soybean inoculated with a marine fungus Aspergillus terreus C23-3, together with seven known compounds including isoflavones 2–6, butyrolactone I (7) and blumenol A (8). Their structures were elucidated by MS, NMR, and ECD. Psoralenone displayed moderate in vitro anti-inflammatory activity in the LPS-induced RAW264.7 cell model. Compound 2 (genistein) showed moderate acetylcholinesterase (AChE) inhibitory activity whereas compounds 2, 5 (biochanin A), 6 (psoralenol), and 7 exhibited potent larvicidal activity against brine shrimp. Compounds 3 (daidzein), 4 (4?-hydroxy-6,7-dimethoxyisoflavone), and 5–7 showed broad-spectrum anti-microbial activity, and compound 7 also showed moderate 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity.     

水体中亚硝酸盐积累的生物过程及影响因素研究进展

亚硝酸盐是氮循环过程的中间产物,其积累超过一定量则会抑制微生物的生长与代谢,也会给人与水生生物带来健康风险。而在高氮污水生物脱氮工艺中,持续维持亚硝酸盐的积累能实现短程硝化过程,降低生物脱氮的能耗进而降低运营成本。本文综述了在水环境中亚硝酸盐积累的生物过程与积累原因,并对影响亚硝酸盐积累的因素进行了总结,旨在为提高污水处理过程中氮的去除效率,降低运营成本,减少排放污水及自然水体中亚硝态氮含量提供参考。     

小麦TaWRKYⅢ-A37和TaWRKYⅡc-D2基因的克隆与表达分析

为了探究小麦(Triticum aestivum L.)WRKY基因的功能,采用同源克隆的方法,从小麦品种‘科农199’中克隆得到2个WRKY基因,分别命名为TaWRKYⅢ-A37和TaWRKYⅡc-D2,并对其进行生物信息学分析和不同逆境胁迫下的表达分析。生物信息学分析显示,TaWRKYⅢ-A37和TaWRKYⅡc-D2基因都含有2个内含子和3个外显子,分别编码206和138个氨基酸,编码蛋白都属于亲水性不稳定非分泌型的核蛋白。系统进化分析表明,TaWRKYⅢ-A37蛋白与其两个同源拷贝的亲缘关系最近,而TaWRKYⅡc-D2蛋白与粗山羊草亲缘关系最近。qRT-PCR结果表明,TaWRKYⅢ-A37和TaWRKYⅡc-D2基因在小麦根、茎和叶中均有表达,前者在根中表达量最高,后者在叶中表达量最高,二者均在茎中低表达;在苗期TaWRKYⅢ-A37基因受到PEG、H_2O_2和ABA胁迫后表达上调,NaCl处理后4～8 h内表达下调且低于对照表达水平,而且在灌浆期受到PEG、NaCl、H_2O_2和ABA胁迫后表达均上调;苗期TaWRKYⅡc-D2基因在NaCl、H_2O_2和ABA胁迫后表达下调,PEG处理2 h时表达上调且高于对照表达水平,并且在灌浆期经PEG和NaCl胁迫后表达下调,受H_2O_2和ABA胁迫后表达上调。该研究结果为深入探究TaWRKYⅢ-A37和TaWRKYⅡc-D2基因的抗逆功能奠定了理论基础。     

Examining differences in phylogenetic composition enhances understanding of the phylogenetic structure of the shrub community in the northeastern Qinghai‐Tibetan Plateau

Periodic climatic oscillations and species dispersal during the postglacial period are two important causes of plant assemblage and distribution on the Qinghai‐Tibet Plateau (QTP). To improve our understanding of the bio‐geological histories of shrub communities on the QTP, we tested two hypotheses. First, the intensity of climatic oscillations played a filtering role during community structuring. Second, species dispersal during the postglacial period contributed to the recovery of species and phylogenetic diversity and the emergence of phylogenetic overdispersion. To test these hypotheses, we investigated and compared the shrub communities in the alpine and desert habitats of the northeastern QTP. Notably, we observed higher levels of species and phylogenetic diversity in the alpine habitat than in the desert habitat, leading to phylogenetic overdispersion in the alpine shrub communities versus phylogenetic clustering in the desert shrub communities. This phylogenetic overdispersion increased with greater climate anomalies. These results suggest that (a) although climate anomalies strongly affect shrub communities, these phenomena do not act as a filter for shrub community structuring, and (b) species dispersal increases phylogenetic diversity and overdispersion in a community. Moreover, our investigation of the phylogenetic community composition revealed a larger number of plant clades in the alpine shrub communities than in the desert shrub communities, which provided insights into plant clade‐level differences in the phylogenetic structures of alpine and desert shrub communities in the northeastern QTP.     

Interplay between formation of photosynthetic complexes and expression of genes for iron–sulfur cluster assembly in Rhodobacter sphaeroides?

Photosynthesis Research - Formation of photosynthetic complexes leads to a higher demand for Fe–S clusters. We hypothesized that in the facultative phototrophic alpha-proteobacterium...