X-ray Phase Contrast Imaging of Cell Isolation with Super-Paramagnetic Microbeads

Super-paramagnetic microbeads are widely used for cell isolation. Evaluation of the binding affinity of microbeads to cells using optical microscopy has been limited by its small scope. Here, magnetic property of microbeads was first investigated by using synchrotron radiation (SR) in-line x-ray phase contrast imaging (PCI). The cell line mouse LLC (Lewis lung carcinoma) was selected for cell adhesion studies. Targeted microbeads were prepared by attaching anti-VEGFR2 (vascular endothelial growth factor receptor-2) antibody to the shell of the microbeads. The bound microbeads were found to better adhere to LLC cells than unbound ones. PCI dynamically and clearly showed the magnetization and demagnetization of microbeads in PE-50 tube. The cells incubated with different types of microbeads were imaged by PCI, which provided clear and real-time visualization of the cell isolation. Therefore, PCI might be considered as a novel and efficient tool for further cell isolation studies.     

Fusarium asiaticum: an Emerging Pathogen Jeopardizing Postharvest Asparagus Spears

Asparagus spears are usually vulnerable to pathogenic micro‐organisms. In this study, 217 pathogens were isolated from symptomatic asparagus, and one highly virulent fungus (designated EXAP‐08) isolated from the rotted asparagus spears in cold storage was characterized in detail. Koch's postulates were checked through pathogenicity tests, indicating that EXAP‐08 infection could cause reproducible rot symptoms similar to those observed on naturally infected asparagus spears, and the pathogenicity of EXAP‐08 was also relatively higher than other Fusarium pathogens, especially at 4°C. Through morphological and molecular identification, EXAP‐08 was characterized as Fusarium asiaticum. This identification was further confirmed by phylogenetic analysis with the Histone gene H3 of EXAP‐08 and other Fusarium species. EXAP‐08 also belongs to 3A‐DON (3‐acetyl‐4‐deoxynivalenol) chemo‐type, and the mycotoxin was detected during the infection of plant, implying the potential risks of mycotoxin contamination in fresh crops infected by this pathogen. Thus, this emerging pathogen threatening edible safety of asparagus spears should deserve particular quarantine inspection in the future.     

Linking membrane dynamics and trafficking to autophagy and the unfolded protein response

Cellular stressors typically induce two protective counter‐responses—autophagy and the unfolded protein response (UPR). It is conceivable that these two endoplasmic reticulum (ER) membrane‐based processes would intersect/interact somehow with the constitutive housekeeping process of exocytic membrane traffic from the ER. How exactly might this occur? Recent evidence indicates that a conserved Rab protein, Rab1/Ypt1p, has functional roles in UPR and autophagy. This molecular switch and its associated effectors may therefore serve to link up a network of cellular responses to stress through changes in membrane dynamics and protein turnover. The notion provides further explanations as to why elevation of Rab1/Ypt1p levels could counter the cytotoxicity of α‐synuclein, and a similar mode of protection may well be at work against other stresses. J. Cell. Physiol. 228: 1638–1640, 2013. © 2013 Wiley Periodicals, Inc.     

LncRNA Bmp1 promotes the healing of intestinal mucosal lesions via the miR-128-3p/PHF6/PI3K/AKT pathway

Intestinal mucosal injuries are directly or indirectly related to many common acute and chronic diseases. Long non-coding RNAs (lncRNAs) are expressed in many diseases, including intestinal mucosal injury. However, the relationship between lncRNAs and intestinal mucosal injury has not been determined. Here, we investigated the functions and mechanisms of action of lncRNA Bmp1 on damaged intestinal mucosa. We found that Bmp1 was increased in damaged intestinal mucosal tissue and Bmp1 overexpression was able to alleviate intestinal mucosal injury. Bmp1 overexpression was found to influence cell proliferation, colony formation, and migration in IEC-6 or HIEC-6 cells. Moreover, miR-128-3p was downregulated after Bmp1 overexpression, and upregulation of miR-128-3p reversed the effects of Bmp1 overexpression in IEC-6 cells. Phf6 was observed to be a target of miR-128-3p. Furthermore, PHF6 overexpression affected IEC-6 cells by activating PI3K/AKT signaling which was mediated by the miR-128-3p/PHF6 axis. In conclusion, Bmp1 was found to promote the expression of PHF6 through the sponge miR-128-3p, activating the PI3K/AKT signaling pathway to promote cell migration and proliferation.Subject terms: Cell growth, Cell migration     

Development of a Compatible Taper Function and Stand-Level Merchantable Volume Model for Chinese Fir Plantations

Chinese fir (Cunninghamia lanceolata [Lamb.] Hook) is one of the most important plantation tree species in China with good timber quality and fast growth. It covers an area of 8.54 million hectare, which corresponds to 21% of the total plantation area and 32% of total plantation volume in China. With the increasing market demand, an accurate estimation and prediction of merchantable volume at tree- and stand-level is becoming important for plantation owners. Although there are many studies on the total tree volume estimation from allometric models, these allometric models cannot predict tree- and stand-level merchantable volume at any merchantable height, and the stand-level merchantable volume model was not seen yet in Chinese fir plantations. This study aimed to develop (1) a compatible taper function for tree-level merchantable volume estimation, and (2) a stand-level merchantable volume model for Chinese fir plantations. This “taper function system” consisted in a taper function, a merchantable volume equation and a total tree volume equation. 46 Chinese fir trees were felled to develop the taper function in Shitai County, Anhui province, China. A second-order continuous autoregressive error structure corrected the inherent serial autocorrelation of different observations in one tree. The taper function and volume equations were fitted simultaneously after autocorrelation correction. The compatible taper function fitted well to our data and had very good performances in diameter and total tree volume prediction. The stand-level merchantable volume equation based on the ratio approach was developed using basal area, dominant height, quadratic mean diameter and top diameter (ranging from 0 to 30 cm) as independent variables. At last, a total stand-level volume table using stand basal area and dominant height as variables was proposed for local forest managers to simplify the stand volume estimation.     

植物凝集素类受体蛋白激酶研究进展

自然界中植物的生长发育受到各种环境变化的影响。为了响应外界各种环境条件,植物演化出一系列识别和传递环境信号的蛋白分子,其中比较典型的是植物细胞质膜上的类受体蛋白激酶(RLKs)。凝集素类受体蛋白激酶(LecRLKs)是类受体蛋白激酶家族中的一个亚族,它主要包含3个结构域:细胞外凝集素结构域、跨膜结构域和细胞内激酶结构域。根据细胞外凝集素结构域的不同,LecRLKs可分为3种不同类型:L、G和C型。近年来,研究表明LecRLKs在植物生物/非生物胁迫和发育调控中发挥非常重要的作用。该文综述了植物凝集素类受体蛋白激酶的研究历史、结构特点、分类以及生物学功能,并重点阐述凝集素类受体蛋白激酶在植物生物/非生物胁迫响应和调控发育方面的功能。对不同类型和不同功能的植物凝集素类受体蛋白激酶进行阐述将有利于对该类蛋白开展功能研究,并为作物改良提供有益借鉴。     

空肠弯曲菌的磁捕获_-荧光PCR检测方法的建立

为提高畜禽类食品中空肠弯曲菌的检出率和灵敏度,应用抗血清和磁性微珠首次制备弯曲菌免疫磁珠,利用弯曲菌免疫磁珠直接捕获检样中目的菌,不需要增菌培养;通过荧光PCR检测鞭毛蛋白A(flaA)基因和/或马尿酸酶(hipO)基因,首次建立空肠弯曲菌的磁捕获-荧光聚合酶链反应(IMC-FPCR)方法.IMC-FPCR法检测空肠弯曲菌方法简便易行,可在24h内完成,特异性好,检测低限达到10cfu/mL,抗干扰性强.IMC-FPCR方法可望解决非可培养状态的空肠弯曲菌检测难题,是一种适用于检验检疫、卫生防疫和农产品安全检验等领域的快速方法.