Targeted regulation of FoxO1 in chondrocytes prevents age‐related osteoarthritis via autophagy mechanism

Autophagy is designated as a biological recycling process to maintain cellular homeostasis by the sequestration of damaged proteins and organelles in plasma and cargo delivery to lysosomes for degradation and reclamation. This organelle recycling process promotes chondrocyte homeostasis and has been previously implicated in osteoarthritis (OA). Autophagy is widely involved in regulating chondrocyte degeneration markers such as MMPs, ADAMSTs and Col10 in chondrocytes. The critical autophagy‐related (ATG) proteins have now been considered the protective factor against late‐onset OA. The current research field proposes that the autophagic pathway is closely related to chondrocyte activity. However, the mechanism is complex yet needs precise elaboration. This review concluded that FoxO1, a forkhead O family protein, which is a decisive mediator of autophagy, facilitates the pathological process of osteoarthritis. Diverse mechanisms regulate the activity of FoxO1 and promote the initiation of autophagy, including the prominent AMPK and Sirt‐2 cellular pathways. FoxO1 transactive is regulated by phosphorylation and acetylation processes, which modulates the downstream ATGs expression. Furthermore, FoxO1 induces autophagy by directly interacting with ATGs proteins, which control the formation of autophagosomes and lysosomes fusion. This review will discuss cutting‐edge evidence that the FoxO–autophagy pathway plays an essential regulator in the pathogenesis of osteoarthritis.     

广西外来入侵植物

通过调查和文献整理,初步确认广西有外来入侵植物114种,隶属于36科80属,其中以菊科的种类最多,有26种。外来入侵植物来源于世界各地,以来源于美洲居多,有87种,占76.3%。入侵植物以草本植物为主,有90种,占78.9%。外来入侵植物主要通过有意引入和无意传入等方式入侵广西。它们的入侵,特别是一些恶性杂草的入侵,给广西农业、林业、人类健康以及生态环境带来巨大的负面影响。加强对外来入侵植物的调查和评估,恢复当地植被和物种的多样性,开展有害生物风险分析是防范外来入侵植物的有效途径。     

对《微生物生态学原理与应用》一书的评价

1981年美国Addison-Wesley出版公司出版了一本《微生物生态学原理与应用》(Microbial Ecology:Fundamentals aud Applications)全书560页。约80万字。作者是美国肯塔基州路易斯维尔(Louisville)大学的R. M. 阿特拉斯(Ronaild M. Atlas)教授及美国新泽西州鲁特杰尔斯(Bu(?)gers)大学的R.巴尔塔(Richard Bartha)教授。他们针对美国许多大学开设的生物生态学课,但又缺乏教材的情况而写了这本教科书。全     

细胞外信号调节激酶1/2信号通路在慢性哮喘模型大鼠支气管平滑肌细胞迁移功能变化中的调控作用

本研究旨在探讨细胞外信号调节激酶1／2(extracellular signal-regulated kinase,ERK1/2)信号通路在慢性哮喘模型大鼠支气管平滑肌细胞(bronchial smooth muscle cells,BSMCs)迁移能力改变中的调控作用。应用卵清蛋白致敏和雾化方法制备大鼠慢性哮喘模型,体外培养大鼠BSMCs,采用免疫荧光细胞化学、Western blot和RT-PCR方法检测ERK1／2信号通路的表达,分别用平面迁移实验和跨膜迁移实验来评价BSMCs的活动和趋向迁移能力,并比较用和不用ERK1／2信号通路干预剂的差异。Western blot结果显示慢性哮喘模型大鼠BSMCs中总ERK1／2(9．13±0．87)较对照组(4．68±0．59)明显增加,磷酸化ERK1／2(p-ERK1/2)占总ERK1／2的比值(0．55±0．05)较对照组(0．48±0．04)显著提高(n=10,P<0．01)。慢性哮喘组ERK1和ERK2 mRNA的表达(1．83±0．24和1．07±0．11)较对照组(0．58±0．14和0．51±0．12)明显增高(n=10,P<0．01)。在平面迁移实验中,慢性哮喘大鼠BSMCs的迁移最远距离是对照组的(2．9±0．1)倍,在ERK1／2激动剂表皮生长因子(epidermal growth factor, EGF)刺激下增加到(5．0±0．2)倍,而在30μmol／L PD98059的作用后下降到(1．7±0．2)倍。正常对照大鼠BSMCs平面迁移能力对PD98059的反应较慢性哮喘组弱,仅在100μmol／L PD98059的作用下下降到(0．8±0．1)倍。跨膜迁移实验中,慢性哮喘大鼠BSMCs的跨膜迁移细胞是对照组的(1．9±0．1)倍,在EGF刺激下增加到(3．1±0．2)倍,而在30μmol/L PD98059作用后下降到(1.45±0.2)倍。这些结果表明慢性哮喘模型大鼠BSMCs的迁移能力明显增强,ERK1／2信号通路在该功能变化的调控中可能发挥了重要作用。     

铅锌砷复合污染对水稻生长的影响

铅锌砷复合污染对水稻生长的影响谢正苗,黄昌勇（浙江农业大学土化系杭州,３１００２９）ＥＦＦＥＣＴＳＯＦＣＯＭＢＩＮＥＤＰＯＬＬＵＴＩＯＮＯＦＬＥＡＤＺＩＮＣＡＲＳＥＮＩＣＯＮＲＩＣＥＧＲＯＷＴＨＸｉｅＺｈｅｎｇｍｉａｏＨｕｎａｇＣｈａｎｇｙｏｎｇ（Ｚ...     

鄂尔多斯高原生态过渡带气候特殊性和气候植物生长指数与畜牧业生产动态分析

鄂尔多斯高原位于我国典型的生态过渡带,气候变化明显,系统反应敏感,因此,现有的主要用于植被和气候空间分类的有关植物与气候关系的模型和指数,均不适合用于鄂尔多斯高原生态过渡带气候。植物动态分析。为此,本文利用位于鄂尔多斯高原中部的伊金霍洛旗３９ａ（１９５３－１９９１）气象资料,分析该地区的气候特点,构建一个可用于描述生态过渡带气候特征的气候植物生长指数,并用与植被动态密切相关的天然放牧条件下（１９５８－１９７９）,该旗牲畜的存栏数和出栏数的历史资料代替植被动态资料,进行鄂尔多斯气候植物生长指数与天然放牧条件下牲畜的存栏数和出栏数的动态分析,构建其ＡＲＭＡＸ模型。研究结果表明,鄂尔多斯高原气候敏感易变,降水年际变化大;高原光、温、水配合并不完全一致,光、温超前,降水滞后,天然植被生产力不高;气候植物生长指数与畜牧生产的动态分析结果表明,该地区在天然放牧情况下,主要依赖于牧场植被长势的畜牧生产与气候－植物生长指数密切相关,说明构建的气候植物生长指数确实在一定程度上反映了该地区的气候与植物生长的关系￣（６－８）。     

松材线虫伴生细菌多样性的宏基组分析

摘要：【目的】松材线虫是松材线虫病的病原,且与其伴生细菌之间存在互作关系,它们构成一个微生态系统。本研究旨在揭示松材线虫-伴生细菌群落细菌多样性。【方法】采用16S rRNA基因文库和454测序对伴生细菌群落的宏基因组进行初步分析。【结果】依据97％序列相似性划分OTU（Operational Taxonomic Unit）,构建的16S rRNA文库包含25个OTU,分别属于Alphaproteobacteria、Betaproteobacteria、Gammaproteobacteria和Bacter     

Dynamics of fertilizer-derived organic nitrogen fractions in an arable soil during a growing season

Background

Inorganic fertilizer is one of the most important anthropogenic inputs which influences soil nutrient turnover in agricultural ecosystems. However, as the key process involved in the maintenance, transformation and stability of soil nitrogen (N), the incorporation and allocation of fertilizer N between different soil organic N (SON) fractions in a growing season remains largely unknown.

Methods

In this study, a field experiment was conducted in triplicate of micro-plots and a total of 200 kg N ha^?1 (¹⁵?N-labeled (NH₄)₂SO₄, 98 atom %) was applied as a basal dressing and two top dressings, at jointing and filling stages, respectively, to a maize crop during one growing season. The distribution and seasonal dynamics of fertilizer N in different SON fractions (i.e., amino acids, amino sugars, hydrolyzable ammonium N and acid insoluble-N) were measured by liquid/gas chromatography–mass spectrometry (LC/GC-MS) and element analysis-combustion-isotope ratio mass spectrometry (EA-C-IRMS) techniques. Path analysis was used to evaluate the transformation processes between organic N fractions derived from fertilizer and N supply strategy in soil-plant system.

Results

The accumulation of fertilizer-derived N in different organic fractions was season-specific. At jointing stage, preferential enrichment of ¹⁵?N was found in soil amino acids plus amino sugars, indicating the active biological immobilization of basal dressing fertilizer N. Nevertheless, there is still a small proportion of fertilizer N stabilized in the acid insoluble fraction. The accumulation of the residual fertilizer N in hydrolyzable ammonium N reached a maximum at filling stage and then declined significantly, implying the rapid release of the fertilizer N remained in mineral forms. The contents of amino acids changed slightly, but they played a very important role in mediating SON transformation.

Conclusion

The hydrolyzable ammonium N was a temporary pool for rapid fertilizer N retention and simultaneously was apt to release N for crop uptake in the current season. In contrast, the amino acids could serve as a transitional pool of available N in the soil-crop system, while the acid insoluble fraction was as a stable pool of fertilizer N. Importantly, there is an interim shift among different pools to maintain soil N turnover; hence N in the amino acid fraction mediates N supply and the depolymerization of SON constituents controls the proceeding of fertilizer N cycling in the soil-plant system.     

The PRiMA-linked Cholinesterase Tetramers Are Assembled from Homodimers: HYBRID MOLECULES COMPOSED OF ACETYLCHOLINESTERASE AND BUTYRYLCHOLINESTERASE DIMERS ARE UP-REGULATED DURING DEVELOPMENT OF CHICKEN BRAIN*

Acetylcholinesterase (AChE) is anchored onto cell membranes by the transmembrane protein PRiMA (proline-rich membrane anchor) as a tetrameric globular form that is prominently expressed in vertebrate brain. In parallel, the PRiMA-linked tetrameric butyrylcholinesterase (BChE) is also found in the brain. A single type of AChE-BChE hybrid tetramer was formed in cell cultures by co-transfection of cDNAs encoding AChE_T and BChE_T with proline-rich attachment domain-containing proteins, PRiMA I, PRiMA II, or a fragment of ColQ having a C-terminal GPI addition signal (Q_N-GPI). Using AChE and BChE mutants, we showed that AChE-BChE hybrids linked with PRiMA or Q_N-GPI always consist of AChE_T and BChE_T homodimers. The dimer formation of AChE_T and BChE_T depends on the catalytic domains, and the assembly of tetramers with a proline-rich attachment domain-containing protein requires the presence of C-terminal “t-peptides” in cholinesterase subunits. Our results indicate that PRiMA- or ColQ-linked cholinesterase tetramers are assembled from AChE_T or BChE_T homodimers. Moreover, the PRiMA-linked AChE-BChE hybrids occur naturally in chicken brain, and their expression increases during development, suggesting that they might play a role in cholinergic neurotransmission.