Neotyphodium endophyte strain and superoxide dismutase activity in perennial ryegrass plants under water deficit

The presence of Neotyphodium endophyte in forage grass tillers has been associated with increased tolerance of abiotic stresses. The effect of four endophyte treatments (plants with three different strains of Neotyphodium lolii compared with plants without endophyte) on superoxide dismutase (SOD) (EC1.15.1.1) activity in Lolium perenne cv ‘Grasslands Samson’ was measured under high and low dehydration regimes in a glasshouse experiment. SOD activity was assayed by a microplate method utilising the inhibition of reduction of a tetrazolium dye by superoxide radicals. A progressive increase in dehydration over 2 weeks reduced shoot fresh weight, dry weight and shoot water content for high, compared with low, moisture-stressed plants. Mean shoot fresh weight was significantly lower for plants with strain AR37 endophyte than for plants with strain AR1 endophyte, wild-type or endophyte-free plants, but there was no interaction between endophyte treatment and dehydration treatment. There were no differences in mean SOD activity between the dehydration treatments, and the four endophyte treatments at any of the harvests. All harvest mean SOD levels for plants in both stress groups, however, were significantly different from the preceding harvest value. Between the first and second week of moisture stress there was a significant endophyte by harvest interaction for mean percentage change in SOD activity when activity in plants with wild-type strain endophyte increased more rapidly than in AR1, AR37 or endophyte-free plants. The results are in agreement with earlier reports suggesting that Neotyphodium endophytes do not have major effects on the water stress physiology of perennial ryegrass, although water deficits applied were not extreme.     

里氏木霉细胞表面表达系统的构建

[目的]烟曲霉(Aspergillus fumigatus)的AfMp1p是一种通过糖基磷脂酰肌醇( glycosylphosphatidylinositol,GPI)修饰定位于细胞壁上的蛋白,其细胞壁定位信号位于蛋白质的C末端.里氏木霉(Trichoderma reesei)是一种重要的工业生产菌种.构建里氏木霉的细胞表面表达系统具有十分重要的意义.[方法]我们将AfMp1p的细胞壁定位GPI信号肽和烟曲霉几丁质酶AfChiB1的N端信号肽分别与绿色荧光蛋白(green fluorescent protein,GFP)的C末端和N末端融合并转化里氏木霉.本文首先对木霉遗传转化系统进行了优化;随后通过Real-time PCR和蛋白定量,对GFP融合蛋白在里氏木霉中不同时期的表达情况进行了研究;最后对里氏木霉表达的GFP融合蛋白进行细胞定位研究.[结果]荧光观察结合Western blot的结果表明,在平台期中期和后期,带有GPI信号的GFP融合蛋白定位于细胞壁.[结论]烟曲霉来源的GPI信号可被里氏木霉识别,本论文所构建的表达系统可用于外源蛋白在里氏木霉中的细胞壁定位表达.     

A novel melatonin agonist Neu-P11 facilitates memory performance and improves cognitive impairment in a rat model of Alzheimer' disease

Previous studies have shown that melatonin is implicated in modulating learning and memory processing. Melatonin also exerts neuroprotective activities against Aβ-induced injury in vitro and in vivo. Neu-P11 (piromelatine, N-(2-(5-methoxy-1H-indol-3-yl)ethyl)-4-oxo-4H-pyran-2-carboxamide) is a novel melatonin (MT1/MT2) receptor agonist and a serotonin 5-HT1A/1D receptor agonist recently developed for the treatment of insomnia. In the present study we firstly investigated whether Neu-P11 and melatonin enhance memory performance in the novel object recognition (NOR) task in rats, and then assessed whether Neu-P11 and melatonin improve neuronal and cognitive impairment in a rat model of Alzheimer' disease (AD) induced by intrahippocampal Aβ_(1–42) injection. The results showed that a single morning or afternoon administration of Neu-P11 enhanced object recognition memory measured at 4 or 24 h after training. Melatonin was effective in the memory facilitating effects only when administered in the afternoon. Further results showed that intrahippocampal Aβ_(1–42) injection resulted in hippocampal cellular loss, as well as decreased learning ability and memory in the Y maze and NOR tasks in rats. Neu-P11 but not melatonin attenuated cellular loss and cognitive impairment in the rat AD model. The current data suggest that Neu-P11 may serve as a novel agent for the treatment of AD.     

Identification of novel caspase/autophagy‐related gene switch to cell fate decisions in breast cancers

Objectives

Caspases, a family of cysteine proteases with unique substrate specificities, contribute to apoptosis, whereas autophagy‐related genes (ATGs) regulate cytoprotective autophagy or autophagic cell death in cancer. Accumulating evidence has recently revealed underlying mechanisms of apoptosis and autophagy; however, their intricate relationships still remain to be clarified. Identification of caspase/ATG switches between apoptosis and autophagy may address this problem.

Materials and methods

Identification of caspase/ATG switches was carried out using a series of elegant systems biology & bioinformatics approaches, such as network construction, hub protein identification, microarray analyses, targeted microRNA prediction and molecular docking.

Results

We computationally constructed the global human network from several online databases and further modified it into the basic caspase/ATG network. On the basis of apoptotic or autophagic gene differential expressions, we identified three molecular switches [including androgen receptor, serine/threonine‐protein kinase PAK‐1 (PAK‐1) and mitogen‐activated protein kinase‐3 (MAPK‐3)] between certain caspases and ATGs in human breast carcinoma MCF‐7 cells. Subsequently, we identified microRNAs (miRNAs) able to target androgen receptor, PAK‐1 and MAPK‐3, respectively. Ultimately, we screened a range of small molecule compounds from DrugBank, able to target the three above‐mentioned molecular switches in breast cancer cells.

Conclusions

We have systematically identified novel caspase/ATG switches involved in miRNA regulation, and predicted targeted anti‐cancer drugs. These findings may uncover intricate relationships between apoptosis and autophagy and thus provide further new clues towards possible cancer drug discovery.

     

葫芦茶地上部分化学成分的研究

运用多种色谱法进行分离纯化,并通过理化性质和波谱数据对化合物进行结构鉴定,研究葫芦茶地上部分的化学成分。结果表明:从葫芦茶地上部分分离并鉴定了13个化合物,分别为山柰酚(1)、山柰酚-3-O-α-L-鼠李糖苷(2)、山柰酚-3-O-β-D-葡萄糖苷(3)、山柰酚-3-O-β-D-芸香糖苷(4)、槲皮素-3-O-α-L-鼠李糖苷(5)、山柰酚-3-O-α-L-鼠李糖(1→6)-β-D-半乳糖苷(6)、槲皮素-3-O-β-D-葡萄糖苷(7)、槲皮素-3-O-α-L-鼠李糖(1→6)-β-D-半乳糖苷(8)、芦丁(9)、间苯三酚-O-β-D-葡萄糖苷(10)、对羟基桂皮酸(11)、RoseosideⅡ(12)、儿茶素(13)。其中化合物2、4、5、6、8、9、10、12为首次从该植物中分离得到。     

Three‐dimensional neural differentiation of embryonic stem cells with ACM induction in microfibrous matrices in bioreactors

The clinical use of pluripotent stem cell (PSC)‐derived neural cells requires an efficient differentiation process for mass production in a bioreactor. Toward this goal, neural differentiation of murine embryonic stem cells (ESCs) in three‐dimensional (3D) polyethylene terephthalate microfibrous matrices was investigated in this study. To streamline the process and provide a platform for process integration, the neural differentiation of ESCs was induced with astrocyte‐conditioned medium without the formation of embryoid bodies, starting from undifferentiated ESC aggregates expanded in a suspension bioreactor. The 3D neural differentiation was able to generate a complex neural network in the matrices. When compared to 2D differentiation, 3D differentiation in microfibrous matrices resulted in a higher percentage of nestin‐positive cells (68% vs. 54%) and upregulated gene expressions of nestin, Nurr1, and tyrosine hydroxylase. High purity of neural differentiation in 3D microfibrous matrix was also demonstrated in a spinner bioreactor with 74% nestin + cells. This study demonstrated the feasibility of a scalable process based on 3D differentiation in microfibrous matrices for the production of ESC‐derived neural cells. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:1013–1022, 2013     

Contribution of cytoskeletal elements to the axonal mechanical properties

Background

Microtubules, microfilaments, and neurofilaments are cytoskeletal elements that affect cell morphology, cellular processes, and mechanical structures in neural cells. The objective of the current study was to investigate the contribution of each type of cytoskeletal element to the mechanical properties of axons of dorsal root and sympathetic ganglia cells in chick embryos.

Results

Microtubules, microfilaments, and neurofilaments in axons were disrupted by nocodazole, cytochalasin D, and acrylamide, respectively, or a combination of the three. An atomic force microscope (AFM) was then used to compress the treated axons, and the resulting corresponding force-deformation information was analyzed to estimate the mechanical properties of axons that were partially or fully disrupted.

Conclusion

We have found that the mechanical stiffness was most reduced in microtubules-disrupted-axons, followed by neurofilaments-disrupted- and microfilaments-disrupted-axons. This suggests that microtubules contribute the most of the mechanical stiffness to axons.