Novel evidence from Taxus fuana forests for niche-neutral process assembling community

Background:Understanding the mechanisms underlying community assembly is helpful for conservation and restoration of communities, particularly those that contain rare and endangered species like Taxus fuana, which are endemic to the Western Himalayas. The niche (limiting similarity) vs. neutral (randomness) assembly of the T.fuana forest community in Gyirong County, Tibet, China, was investigated. The net relatedness index (NRI) was calculated using a phylogenetic tree. The phylogenetic characteristics of the community and its relationships with environment were analyzed.Results:The value of the mean NRI at the community level was less than-1.96, indicating that the phylogenetic structure was overdispersed;whereas majority of the NRIs at the tree, shrub, and herb layers were within-1.96 to1.96, indicating random dispersion. Environmental factors accounted for 44.38%, 46.52%, 24.04%, and 14.07%of the variation at the community level, tree, shrub, and herb layer, respectively. The phylogenetic structure at the community level and tree layer were significantly influenced by both topographic and soil factors, while shrub and herb layers tended to be affected by a single environmental factor.Conclusions:Community assembly of the T. fuana forest was simultaneously affected by niche and neutral processes, and their variations were closely related to the environment. Neutral process dominated community assembly in the shrub and herb layers. However, the interaction of limiting similarity and randomness played a dominant role at the community level and tree layer;and contributed to maintenance of biodiversity stability. The synergy of multiple environmental factors had a more obvious influence on community assembly than individual environmental factors, especially at the community level. These findings would help to understand the conservation of rare and endangered tree species, such as T. fuana, in the native community;and highlight the importance of random and non-random processes in assembly and biodiversity maintenance of alpine plant communities.

Functions and mechanisms of protein lysine butyrylation(Kbu):Therapeutic implications in human diseases

Post-translational modifications(PTM)are covalent modifications of proteins or peptides caused by proteolytic cleavage or the attachment of moieties to one or more amino acids.PTMs play essential roles in biological function and regulation and have been linked with several diseases.Modifications of protein acylation(Kac),a type of PTM,are known to induce epigenetic regulatory processes that promote various diseases.Thus,an increasing number of studies focusing on acylation modifications are being undertaken.Butyrylation(Kbu)is a new acylation process found in animals and plants.Kbu has been recently linked to the onset and progression of several diseases,such as cancer,cardiovascular diseases,diabetes,and vascular dementia.Moreover,the mode of action of certain drugs used in the treatment of lymphoma and colon cancer is based on the regulation of butyrylation levels,suggesting that butyrylation may play a therapeutic role in these diseases.In addition,butyrylation is also commonly involved in rice gene expression and thus plays an important role in the growth,development,and metabolism of rice.The tools and analytical methods that could be utilized for the prediction and detection of lysine butyrylation have also been investigated.This study reviews the potential role of histone Kbu,as well as the mechanisms underlying this process.It also summarizes various enzymes and analytical methods associated with Kbu,with the goal of providing new insights into the role of Kbu in gene regulation and diseases.

CRISPR/Cas9 therapeutics:progress and prospects

Clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)gene-editing technology is the ideal tool of the future for treating diseases by permanently correcting deleterious base mutations or disrupting disease-causing genes with great precision and efficiency.A variety of efficient Cas9 variants and derivatives have been developed to cope with the complex genomic changes that occur during diseases.However,strategies to effectively deliver the CRISPR system to diseased cells in vivo are currently lacking,and nonviral vectors with target recognition functions may be the focus of future research.Pathological and physiological changes resulting from disease onset are expected to serve as identifying factors for targeted delivery or targets for gene editing.Diseases are both varied and complex,and the choice of appropriate gene-editing methods and delivery vectors for different diseases is important.Meanwhile,there are still many potential challenges identified when targeting delivery of CRISPR/Cas9 technology for disease treatment.This paper reviews the current developments in three aspects,namely,gene-editing type,delivery vector,and disease characteristics.Additionally,this paper summarizes successful examples of clinical trials and finally describes possible problems associated with current CRISPR applications.

西藏极小种群野生植物密叶红豆杉种群的性比及雌雄空间格局

雌雄异株植物种群具有性比和雌雄个体空间分布格局,这对个体成功繁殖、种群生存潜力、天然更新能力和遗传多样性的维持都是重要的,对于珍稀濒危雌雄异株植物种群尤其如此。密叶红豆杉(Taxus fuana)为国家I级重点保护植物,是首批列入《全国极小种群野生植物拯救保护工程规划》的120种极小种群野生植物之一,具有重要的生态和经济价值。但目前关于密叶红豆杉种群生态学方面的研究,尤其是性比结构与空间分布格局在国内外鲜有报道。本文对西藏吉隆地区的6个天然密叶红豆杉种群(吉普、多甫、朗久、吉隆、开热和唐蕃)进行了实地调查,研究其性比结构及其空间分布格局。结果表明,调查的6个种群中总计雄株1,651株,雌株1,231株,仅吉普(雄/雌=1.89)与吉隆(雄/雌=1.39)两个种群有显著的性别偏倚现象且显著偏雄性(P<0.001)。6个种群雌雄植株间的空间相关性不强,整体趋于相互独立。不同径级间,吉隆和开热种群的性比格局相似,均在小径级上性比显著偏雄性,而吉普种群则在中等径级上显著偏雄性。综上,不同密叶红豆杉种群的大小、性比、雌雄个体的大小级结构以及空间分布格局等均表现出不同。因此,需要结合各个种群本身的发展动态、受干扰的类型以及各区域环境因子的差异进行有针对性的保护。

What Determines China's Grain Imports and Self-sufficiency? The Role of Rising Domestic Costs and Varying World Market Prices

China s grain sectors have faced unprecedented challenges in recent years as the ever-increasing and historically high level of grain output has failed to reduce grain imports. On the contrary, high grain imports and high domestic stock have accompanied historically high domestic output, a situation dubbed the "triple high" phenomenon in current policy discussion. This paper explores the role of widening domestic-world market price gaps in determining the triple high phenomenon.Unlike earlier studies that relied on production capacities, this paper argues that domestic production and demand (hence imports) are functions of domestic and world market prices and proposes an analytical framework to explicitly capture such price gaps under restricted trade linkages in general equilibrium. Following this approach, a set of price scenarios for the 2011-2020 period are constructed and simulated in a computable general equilibrium model. Results from the core scenarios, in which recent domestic and world market price trends are assumed to continue, suggest that further widening price gaps would substantially increase grain imports and reduce domestic output (by 60 million tons) and self-sufficiency ratios from base levels. In the alternative scenarios with larger (smaller) price gaps, we find higher (lower) imports and larger (smaller) decreases in domestic output and self-sufficiency ratios. Such results provide important policy implications as China's agricultural policy undergoes significant adjustment.