14 research outputs found
AXY3 encodes a α-xylosidase that impacts the structure and accessibility of the hemicellulose xyloglucan in Arabidopsis plant cell walls
Xyloglucan is the most abundant hemicellulose in the walls of dicots such as Arabidopsis. It is part of the load-bearing structure of a plant cell and its metabolism is thought to play a major role in cell elongation. However, the molecular mechanism by which xyloglucan carries out this and other functions in planta is not well understood. We performed a forward genetic screen utilizing xyloglucan oligosaccharide mass profiling on chemically mutagenized Arabidopsis seedlings to identify mutants with altered xyloglucan structures termed axy-mutants. One of the identified mutants, axy3.1, contains xyloglucan with a higher proportion of non-fucosylated xyloglucan subunits. Mapping revealed that axy3.1 contains a point mutation in XYLOSIDASE1 (XYL1) known to encode for an apoplastic glycoside hydrolase releasing xylosyl residues from xyloglucan oligosaccharides at the non-reducing end. The data support the hypothesis that AXY3/XYL1 is an essential component of the apoplastic xyloglucan degradation machinery and as a result of the lack of function in the various axy3-alleles leads not only to an altered xyloglucan structure but also a xyloglucan that is less tightly associated with other wall components. However, the plant can cope with the excess xyloglucan relatively well as the mutant does not display any visible growth or morphological phenotypes with the notable exception of shorter siliques and reduced fitness. Taken together, these results demonstrate that plant apoplastic hydrolases have a larger impact on wall polymer structure and function than previously thought
Effect of Heart Rate on Stroke Recurrence and Mortality in Acute Ischemic Stroke With Atrial Fibrillation
Electrocardiographic Criteria for Diagnosis of Irregular Broad Complex Tachycardia with a High Sensitivity for Preexcited Atrial Fibrillation
Electrophysiological Characteristics of Accessory Pathways with Prolonged Retrograde Conduction
Frequent activating FGFR2 mutations in endometrial carcinomas parallel germline mutations associated with craniosynostosis and skeletal dysplasia syndromes
Clinical Cancer Advances 2009: Major Research Advances in Cancer Treatment, Prevention, and Screening—A Report From the American Society of Clinical Oncology
Successful Catheter Ablation of Left Ventricular Epicardial Tachycardia Originating From the Great Cardiac Vein
Electrophysiological and electrocardiographic predictors of ventricular arrhythmias originating from the left ventricular outflow tract within and below the coronary sinus cusps
Heterogeneity in the chemistry, structure and function of plant cell walls
Higher plants resist the forces of gravity and powerful lateral forces through the cumulative strength of the walls that surround individual cells. These walls consist mainly of cellulose, noncellulosic polysaccharides and lignin, in proportions that depend upon the specific functions of the cell and its stage of development. Spatially and temporally controlled heterogeneity in the physicochemical properties of wall polysaccharides is observed at the tissue and individual cell levels, and emerging in situ technologies are providing evidence that this heterogeneity also occurs across a single cell wall. We consider the origins of cell wall heterogeneity and identify contributing factors that are inherent in the molecular mechanisms of polysaccharide biosynthesis and are crucial for the changing biological functions of the wall during growth and development. We propose several key questions to be addressed in cell wall biology, together with an alternative two-phase model for the assembly of noncellulosic polysaccharides in plants.Rachel A Burton, Michael J Gidley & Geoffrey B Finche