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991.
Assaf Zemach Laju K. Paul Perry Stambolsky Varda Rotter 《Experimental cell research》2009,315(20):3554-3562
The Arabidopsis MBD7 (AtMBD7) - a naturally occurring poly MBD protein - was previously found to be functional in binding methylated-CpG dinucleotides in vitro and localized to highly methylated chromocenters in vivo. Furthermore, AtMBD7 has significantly lower mobility within the nucleus conferred by cooperative activity of its three MBD motifs. Here we show that besides the MBD motifs, AtMBD7 possesses a strong chromatin binding domain located at its C-terminus designated sticky-C (StkC). Mutational analysis showed that a glutamic acid residue near the C-terminus is essential though not sufficient for the StkC function. Further analysis demonstrated that this motif can render nuclear proteins highly immobile both in plant and animal cells, without affecting their native subnuclear localization. Thus, the C-terminal, StkC motif plays an important role in fastening AtMBD7 to its chromosomal, CpG-methylated sites. It may be possible to utilize this motif for fastening nuclear proteins to their chromosomal sites both in plant and animal cells for research and gene therapy applications. 相似文献
992.
Charles A. Day 《生物化学与生物物理学报:生物膜》2009,1788(1):245-17090
Studies of the diffusion of proteins and lipids in the plasma membrane of cells have long pointed to the presence of membrane domains. A major challenge in the field of membrane biology has been to characterize the various cellular structures and mechanisms that impede free diffusion in cell membranes and determine the consequences that membrane compartmentalization has on cellular biology. In this review, we will provide a brief summary of the classes of domains that have been characterized to date, focusing on recent efforts to identify the properties of lipid rafts in cells through measurements of protein and lipid diffusion. 相似文献
993.
Xuezheng Song Yi Lasanajak Carlos Rivera-Marrero Anthony Luyai Margaret Willard David F. Smith Richard D. Cummings 《Analytical biochemistry》2009,395(2):1288-1727
Glycan microarray technology has become a successful tool for studying protein–carbohydrate interactions, but a limitation has been the laborious synthesis of glycan structures by enzymatic and chemical methods. Here we describe a new method to generate quantifiable glycan libraries from natural sources by combining widely used protease digestion of glycoproteins and Fmoc chemistry. Glycoproteins including chicken ovalbumin, bovine fetuin, and horseradish peroxidase (HRP) were digested by Pronase, protected by FmocCl, and efficiently separated by 2D-HPLC. We show that glycans from HRP glycopeptides separated by HPLC and fluorescence monitoring retained their natural reducing end structures, mostly core α1,3-fucose and core α1,2-xylose. After simple Fmoc deprotection, the glycans were printed on NHS-activated glass slides. The glycans were interrogated using plant lectins and antibodies in sera from mice infected with Schistosoma mansoni, which revealed the presence of both IgM and IgG antibody responses to HRP glycopeptides. This simple approach to glycopeptide purification and conjugation allows for the development of natural glycopeptide microarrays without the need to remove and derivatize glycans and potentially compromise their reducing end determinants. 相似文献
994.
995.
996.
Fan Jia Srinivas S. L. Gampala Amandeep Mittal Qingjun Luo Christopher D. Rock 《Plant molecular biology》2009,70(6):693-708
The 14,200 available full length Arabidopsis thaliana cDNAs in the universal plasmid system (UPS) donor vector pUNI51 should be applied broadly and efficiently to leverage a “functional
map-space” of homologous plant genes. We have engineered Cre-lox UPS host acceptor vectors (pCR701- 705) with N-terminal epitope
tags in frame with the loxH site and downstream from the maize Ubiquitin promoter for use in transient protoplast expression assays and particle bombardment transformation of monocots. As an example
of the utility of these vectors, we recombined them with several Arabidopsis cDNAs encoding Ser/Thr protein phosphatase type 2C (PP2Cs) known from genetic studies or predicted by hierarchical clustering
meta-analysis to be involved in ABA and stress responses. Our functional results in Zea mays mesophyll protoplasts on ABA-inducible expression effects on the Late Embryogenesis Abundant promoter ProEm:GUS reporter were consistent with predictions and resulted in identification of novel activities of some PP2Cs. Deployment
of these vectors can facilitate functional genomics and proteomics and identification of novel gene activities.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
997.
Flower visiting beetles possess numerous structural adaptations of their mouthparts to adhere and ingest pollen grains. Using
a Cryo-SEM approach the examination of the mouthparts in rapidly frozen Cetonia aurata (Scarabaeidae) indicates a previously unknown technique of pollen uptake in Coleoptera. Cryo-SEM micrographs of the mouthparts
reveal a fluid covering the bristles on the buccal surface. In this way the bristles of the galeae form a wet brush which
represents the primary organ of pollen uptake. The fluid improves adhesion of pollen to bristles lacking any specialized adhering
surface or highly sculptured cuticle as present in other pollen feeding Coleoptera. The well developed mola region of the
otherwise non-biting mandibles of C. aurata indicates that these beetles open pollen grains mechanically before ingestion. Examination of gut content demonstrated that
crushed and intact pollen occur in all regions. The Cryo-SEM method represents a new approach to study functional morphology
including the interaction of microstructures and fluids on cuticular surfaces of insects.
Handling editor: Gimme Walter 相似文献
998.
999.
Gaetano T. Montelione Cheryl Arrowsmith Mark E. Girvin Michael A. Kennedy John L. Markley Robert Powers James H. Prestegard Thomas Szyperski 《Journal of structural and functional genomics》2009,10(2):101-106
This Perspective, arising from a workshop held in July 2008 in Buffalo NY, provides an overview of the role NMR has played
in the United States Protein Structure Initiative (PSI), and a vision of how NMR will contribute to the forthcoming PSI-Biology
program. NMR has contributed in key ways to structure production by the PSI, and new methods have been developed which are
impacting the broader protein NMR community. 相似文献
1000.
Aims: To compare conventional plate counting and indirect conductimetry as techniques for ranking the resistance of Salmonella spp. to processing stressors.
Methods and Results: Forty Salmonella isolates were subjected to three separate stressors used in food processing; irradiation, heat and high hydrostatic pressure (HHP). Total viable counts (TVC) using conventional plate counts and time to detection (TTD) using indirect conductimetry were determined. A significant negative correlation between TVC and TTD was seen with irradiation ( P < 0·01) and heat ( P < 0·05) but not HHP.
Conclusions: For a group of salmonellas, indirect conductimetry can rapidly determine a ranking of isolate sensitivity to irradiation and heat. However, for HHP, the results indicated that conventional plate counting alone cannot be used to determine sensitivity.
Significance and Impact of the Study: The resistance of micro-organisms to processing systems must be ranked to allow the selection of appropriate isolates for process validation. TTD measurements allow rapid screening of salmonellas to rank isolates for resistance to irradiation and heat stress. However, following HHP, the TVC of survivors is independent of the time required for growth to a set cell density and therefore it cannot be used as the sole measure of relative stress resistance. 相似文献
Methods and Results: Forty Salmonella isolates were subjected to three separate stressors used in food processing; irradiation, heat and high hydrostatic pressure (HHP). Total viable counts (TVC) using conventional plate counts and time to detection (TTD) using indirect conductimetry were determined. A significant negative correlation between TVC and TTD was seen with irradiation ( P < 0·01) and heat ( P < 0·05) but not HHP.
Conclusions: For a group of salmonellas, indirect conductimetry can rapidly determine a ranking of isolate sensitivity to irradiation and heat. However, for HHP, the results indicated that conventional plate counting alone cannot be used to determine sensitivity.
Significance and Impact of the Study: The resistance of micro-organisms to processing systems must be ranked to allow the selection of appropriate isolates for process validation. TTD measurements allow rapid screening of salmonellas to rank isolates for resistance to irradiation and heat stress. However, following HHP, the TVC of survivors is independent of the time required for growth to a set cell density and therefore it cannot be used as the sole measure of relative stress resistance. 相似文献