Zea mays (maize) pollen exines have been purified with the use of differential centrifugation and sucrose gradients, followed by mild detergent and high salt treatment. The final exine fraction is highly purified from other organelles and subcellular structures as assayed by transmission electron microscopy. Using mature maize pollen as the starting material, 0.2 to 0.3% of the total pollen pro...

The biosynthesis of plant cell wall polysaccharides requires the concerted action of nucleotide sugar interconversion enzymes, nucleotide sugar transporters, and glycosyl transferases. How cell wall synthesis in planta is regulated, however, remains unclear. The root epidermal bulger 1 (reb1) mutant in Arabidopsis thaliana is partially deficient in cell wall arabinogalactan-protein (AGP), indic...

Arabinogalactan-proteins (AGPs) are ubiquitous cell wall components present throughout the plant kingdom. They are extensively post translationally modified by conversion of proline to hydroxyproline (Hyp) and by addition of arabinogalactan (AG) polysaccharides to Hyp residues. Two small gene subfamilies within the CAZy GT31 family, referred to as Hyp-galactosyltransferases (Hyp-GALTs and HPGTs...

An in vitro faecal incubation system was used to study the metabolism of complex carbohydrates by intestinal bacteria. Homogenates of human faeces were incubated anaerobically with added lactulose, pectin, the hemicellulose arabinogalactan, and cellulose, both before and after subjects had been pre-fed each carbohydrate. Fermentation of added substrate was assessed by the production of short-ch...

Female gametogenesis in most flowering plants depends on the predetermined selection of a single meiotically derived cell, as the three other megaspores die without further division or differentiation. Although in Arabidopsis thaliana the formation of the functional megaspore (FM) is crucial for the establishment of the gametophytic generation, the mechanisms that determine the specification an...

The relationships among platelet size. density. protein and sialic acid content. and age have been investigated. More than 90% of the platelets were obtained from anticoagulated rabbit blood and separated into three density subpopulations by centrifugation in isosmolar discontinuous arabinogalactan (STRactan) density gradients. The size of the most dense platelets was greater than that of the l...

The antimycobacterial compound ethambutol [Emb; dextro-2,2'-(ethylenediimino)-di-1-butanol] is used to treat tuberculosis as well as disseminated infections caused by Mycobacterium avium. The critical target for Emb lies in the pathway for the biosynthesis of cell wall arabinogalactan, but the molecular mechanisms for drug action and resistance are unknown. The cellular target for Emb was sough...

Arabinogalactan proteins (AGPs) are involved in many aspects of plant development. In this study, biochemical and genetic approaches demonstrated that AGPs are abundant in developing fibers and may be involved in fiber initiation and elongation. To further investigate the role of AGPs during fiber development, a fasciclin-like arabinogalactan protein gene (GhFLA1) was identified in cotton (Goss...