Saccharide analysis of onion outer epidermal walls.

Background: Epidermal cell walls have special structural and biological roles in the life of the plant. Typically they are multi-ply structures encrusted with waxes and cutin which protect the plant from dehydration and pathogen attack. These characteristics may also reduce chemical and enzymatic deconstruction of the wall for sugar analysis and conversion to biofuels.

Pectin methylesterase selectively softens the onion epidermal wall yet reduces acid-induced creep.

De-esterification of homogalacturonan (HG) is thought to stiffen pectin gels and primary cell walls by increasing calcium cross-linking between HG chains. Contrary to this idea, recent studies found that HG de-esterification correlated with reduced stiffness of living tissues, measured by surface indentation. The physical basis of such apparent wall softening is unclear, but possibly involves complex biological responses to HG modification.

Kinetic analysis of cellulose synthase of Gluconacetobacter hansenii in whole cells and in purified form.

The Gram-negative bacterium, Gluconacetobacter hansenii, has been long studied and is a model for cellulose synthesis. It produces cellulose, using the enzyme AcsA-AcsB, of exceptionally high crystallinity in comparison to the cellulose of higher plants. We determined the rate of cellulose synthesis in whole cells measured as moles of glucose incorporated into cellulose per second per mole of enzyme.

Initiation, Elongation, and Termination of Bacterial Cellulose Synthesis.

Cellulose is the major component of the plant cell wall and composed of β-linked glucose units. Use of cellulose is greatly impacted by its physical properties, which are dominated by the number of individual cellulose strand within each fiber and the average length of each strand. Our work described herein provides a complete mechanism for cellulose synthase accounting for its processivity and mechanism of initiation.

Gouty Arthritis: A Review of Acute Management and Prevention.

Gouty arthritis is one of the most common rheumatic diseases. The clinical burden of gouty arthritis has historically been well recognized; however, gout is often misdiagnosed and mismanaged. The prevalence of gout is rising and is likely attributed to several factors including increased incidence of comorbidities, lifestyle factors, and increased use of causative medications.

The valine and lysine residues in the conserved FxVTxK motif are important for the function of phylogenetically distant plant cellulose synthases.

Cellulose synthases (CESAs) synthesize the β-1,4-glucan chains that coalesce to form cellulose microfibrils in plant cell walls. In addition to a large cytosolic (catalytic) domain, CESAs have eight predicted transmembrane helices (TMHs). However, analogous to the structure of BcsA, a bacterial CESA, predicted TMH5 in CESA may instead be an interfacial helix.

Comparison of new-onset gout in adults prescribed chlorthalidone vs. hydrochlorothiazide for hypertension.

This study assessed the risk of new-onset gout following prescribing of hydrochlorothiazide (HCTZ) compared with chlorthalidone (CTD). This retrospective cohort analysis used administrative claims from 2000 to 2012 to identify patients aged 18 to 89 years with hypertension who were prescribed CTD or HCTZ. Patients were excluded if they had a prior diagnosis of gout, conditions or prescription claims for medications that alter risk of gout, or if they switched between these two diuretics.

Gene-sharing networks reveal organizing principles of transcriptomes in Arabidopsis and other multicellular organisms.

Understanding tissue-related gene expression patterns can provide important insights into gene, tissue, and organ function. Transcriptome analyses often have focused on housekeeping or tissue-specific genes or on gene coexpression. However, by analyzing thousands of single-gene expression distributions in multiple tissues of Arabidopsis thaliana, rice (Oryza sativa), human (Homo sapiens), and mouse (Mus musculus), we found that these organisms primarily operate by gene sharing, a phenomenon where, in each organism, most genes exhibit a high expression level in a few key tissues.

Boolean modeling of transcriptome data reveals novel modes of heterotrimeric G-protein action.

Heterotrimeric G-proteins mediate crucial and diverse signaling pathways in eukaryotes. Here, we generate and analyze microarray data from guard cells and leaves of G-protein subunit mutants of the model plant Arabidopsis thaliana, with or without treatment with the stress hormone, abscisic acid. Although G-protein control of the transcriptome has received little attention to date in any system, transcriptome analysis allows us to search for potentially uncommon yet significant signaling mechanisms.