Nicotiana tabacum actin-depolymerizing factor 2 is involved in actin-driven,auxin-dependent patterning

Polar transport of auxin has been identified as a central element of pattern formation. To address the underlying cellular mechanisms, we use the tobacco cell line (Nicotiana tabacum L. cv. Bright Yellow 2; BY-2) as model. We showed previously that cell divisions within a cell file are synchronized by polar auxin flow, linked to the organization of actin filaments (AF) which, in turn, is modified via actin-binding proteins (ABPs). From a preparatory study for disturbed division synchrony in cell lines overexpressing different ABPs, we identified the actin depolymerizing factor 2 (ADF2). A cell line overexpressing GFP-NtADF2 was specifically affected in division synchrony. The cell division pattern could be rescued by addition of Phosphatidylinositol 4,5-bisphosphate (PIP₂) or by phalloidin. These observations allow to draw first conclusions on the pathway linking auxin signalling via actin reorganization to synchronized cell division placing the regulation of cortical actin turnover by ADF2 into the focus.     

地衣芽孢杆菌W10菌液和抗菌蛋白对桃果实贮藏保鲜效果的影响

以桃‘沪油018’(Amygdalus persica ‘Huyou 018’)果实为试验材料,经地衣芽孢杆菌W10菌液及其抗菌蛋白浸果后常温条件下(25 ℃)贮藏,定期测量桃果各项保鲜指标。结果表明,与对照桃果实比较,地衣芽孢杆菌W10菌液和抗菌蛋白处理可提高桃果实色泽、硬度和可溶性固形物含量,显著降低桃果失重率和腐烂率。经菌液处理桃果腐烂率降低至20%,菌液抑制桃果腐烂效果与多菌灵类似。菌液和抗菌蛋白在提高贮藏期桃果品质方面差异不显著。地衣芽孢杆菌W10菌液和抗菌蛋白应用于采后桃果的贮藏保鲜效果较好,潜力较大。     

The impact of microgravity-based proteomics research

Proteomics is performed in microgravity research in order to determine protein alterations occurring qualitatively and quantitatively, when single cells or whole organisms are exposed to real or simulated microgravity. To this purpose, antibody-dependent (Western blotting, flow cytometry, Luminex^® technology) and antibody-independent (mass spectrometry, gene array) techniques are applied. The anticipated findings will help to understand microgravity-specific behavior, which has been observed in bacteria, as well as in plant, animal and human cells. To date, the analyses revealed that cell cultures are more sensitive to microgravity than cells embedded in organisms and that proteins changing under microgravity are highly interactive. Furthermore, one has to distinguish between primary gravity-induced and subsequent interaction-dependent changes of proteins, as well as between direct microgravity-related effects and indirect stress responses. Progress in this field will impact on tissue engineering and medicine and will uncover possibilities of counteracting alterations of protein expression at lowered gravity.     

农杆菌介导的日本落叶松胚性细胞遗传转化研究

基于体细胞胚胎发生技术平台,利用携带pSuper1300+质粒,以潮霉素为筛选标记基因的农杆菌GV3101介导日本落叶松遗传转化,对植物受体材料生理状态、农杆菌浓度和浸染时间以及共培养时间等影响因素进行了研究、分析和讨论.结果表明:综合优化各影响因素,生长旺盛的日本落叶松胚性细胞,经浓度为0.4(OD600)的农杆菌浸染10min,共培养2d,再用含400mg/L的头孢霉素的液体培养基清洗脱菌,然后在含400mg/L的头孢霉素固体培养基上恢复培养,并置于含5mg/L潮霉素的固体培养基上多次筛选,最终共获得54个抗性细胞系,转化率平均为0.94个/g.PCR检测鉴定,所有抗性细胞系均为阳性转化体,并排除了农杆菌污染导致的假阳性.研究建立并优化了农杆菌介导的日本落叶松遗传转化技术,为进行遗传改良和基因功能鉴定提供有利平台.     

The Collins’ monster,a spinous suspension-feeding lobopodian from the Cambrian Burgess Shale of British Columbia

Lobopodians, a paraphyletic group of rare but morphologically diverse Palaeozoic vermiform animals bearing metameric appendages, are key to the origin of extant panarthropods. First discovered in 1983 on Mount Stephen (Yoho National Park, British Columbia), the Cambrian (Wuliuan) Burgess Shale lobopodian nicknamed ‘Collins’ monster’ is formally described as Collinsovermis monstruosus gen. et sp. nov. A formal systematic treatment of the comparable and poorly known lobopodian Acinocricus stichus from Utah is also provided. The body of Collinsovermis is plump and compact but shows the diagnostic suspension-feeding characters of luolishaniid lobopodians. It possesses 14 contiguous pairs of lobopods, lacking space between them. The 6 anterior pairs are elongate, adorned with about 20 pairs of long and slightly curved ventral spinules arranged in a chevron-like pattern. These appendages terminate in a pair of thin claws and their dorsal surfaces are covered in minute spines or setae. The 8 posterior lobopod pairs, which attach to a truncated body termination, are stout and smooth, each terminated by a single strong recurved claw. Each somite bears a pair of dorsal spines; somites 4 and posteriad bear an additional median spine. The spines on somites 1–3 are much shorter than the spines on the remaining somites. The head is short, bears a terminal mouth and a pair of antenniform outgrowths, and is covered by an oblong sclerite. Collinsovermis, plus Collinsium and Acinocricus, are found to comprise a sub-group of stout luolishaniid lobopodians with remarkably long spinules on the front lobopods, interpreted here as a clade (Teratopodidae fam. nov.) This clade is distinct from both the comparatively slenderer Luolishania and a sub-group composed of Facivermis and Ovatiovermis lacking body sclerites. Luolishaniids were mostly sessile forerunners of arthropods that had coupled efficient suspension-feeding devices and, as in Collinsovermis, strong defensive or deterrent features.     

植物细胞工程技术生产紫杉醇研究进展

紫杉醇是一种二萜类生物碱,主要从红豆杉树皮中分离提取。目前采用植物细胞工程技术是提高紫杉醇产率、保护稀缺资源红豆杉、解决紫杉醇药源紧缺的一种最有效方法。该文对近十年来国内外有关采用植物细胞工程技术生产紫杉醇的研究进展,包括红豆杉细胞系的建立、悬浮培养条件的研究、生物反应器培养以及紫杉醇合成代谢调控方面的最新研究进展进行综述。并重点论述了前体、诱导子和代谢支路抑制剂对红豆杉细胞悬浮培养生产紫杉醇的影响,为植物细胞工程技术生产紫杉醇提供借鉴和参考。     

An Efficient Rice Mutagenesis System Based on Suspension-Cultured Cells

Plant mutants are important bio-resources for crop breeding and gene functional studies. Conventional methods for generating mutant libraries by mutagenesis of seeds with physical or chemical agents are of low efficiency. Here, we developed a highly-efficient ethyl methanesulfonate (EMS) mutagenesis system based on suspension-cultured cells, with rice (Oryza sativa L.) as an example. We show that treatment of suspension-cultured tiny cell clusters with 0.4% EMS for 18-22h followed by differentiation and regeneration produced as high as 29.4% independent mutant lines with visible phenotypic variations, including a number of important agronomic traits such as grain size, panicle size, grain or panicle shape, tiller number and angle, heading date, male sterility, and disease sensitivity. No mosaic mutant was observed in the mutant lines tested. In this mutant library, we obtained a mutant with an abnormally elongated uppermost internode. Sequencing and functional analysis revealed that this is a new allelic mutant of eui (elongated uppermost internode) caused by two point mutations in the first exon of the EUI gene, representing a successful example of this mutagenesis system.     

An approach for the improved immobilization of penicillin G acylase onto macroporous poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) as a potential industrial biocatalyst

The use of penicillin G acylase (PGA) covalently linked to insoluble carrier is expected to produce major advances in pharmaceutical processing industry and the enzyme stability enhancement is still a significant challenge. The objective of this study was to improve catalytic performance of the covalently immobilized PGA on a potential industrial carrier, macroporous poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) [poly(GMA‐co‐EGDMA)], by optimizing the copolymerization process and the enzyme attachment procedure. This synthetic copolymer could be a very promising alternative for the development of low‐cost, easy‐to‐prepare, and stable biocatalyst compared to expensive commercially available epoxy carriers such as Eupergit or Sepabeads. The PGA immobilized on poly(GMA‐co‐EGDMA) in the shape of microbeads obtained by suspension copolymerization appeared to have higher activity yield compared to copolymerization in a cast. Optimal conditions for the immobilization of PGA on poly(GMA‐co‐EGDMA) microbeads were 1 mg/mL of PGA in 0.75 mol/L phosphate buffer pH 6.0 at 25°C for 24 h, leading to the active biocatalyst with the specific activity of 252.7 U/g dry beads. Chemical amination of the immobilized PGA could contribute to the enhanced stability of the biocatalyst by inducing secondary interactions between the enzyme and the carrier, ensuring multipoint attachment. The best balance between the activity yield (51.5%), enzyme loading (25.6 mg/g), and stability (stabilization factor 22.2) was achieved for the partially modified PGA. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:43–53, 2016     

Serum replacement with albumin‐associated lipids prevents excess aggregation and enhances growth of induced pluripotent stem cells in suspension culture

Suspension culture systems are currently under investigation for the mass production of pluripotent stem (PS) cells for tissue engineering; however, the control of cell aggregation in suspension culture remains challenging. Existing methods to control aggregation such as microwell culture are difficult to scale up. To address this issue, in this study a novel method that incorporates the addition of KnockOut Serum Replacement (KSR) to the PS cell culture medium was described. The method regulated cellular aggregation and significantly improved cell growth (a 2‐ to 10‐fold increase) without any influence on pluripotency. In addition, albumin‐associated lipids as the major working ingredient of KSR responsible for this inhibition of aggregation were identified. This is one of the simplest methods described to date to control aggregation and requires only chemically synthesizable reagents. Thus, this method has the potential to simplify the mass production process of PS cells and thus lower their cost. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1009–1016, 2016