Covalent cross-linking of cell-wall polysaccharides through esterified diferulates as a maize resistance mechanism against corn borers.

There is strong evidence to suggest that cross-linking of cell-wall polymers through ester-linked diferulates has a key role in plant resistance to pests; however, direct experimentation to provide conclusive proof is lacking. This study presents an evaluation of the damage caused by two corn borer species on six maize populations particularly selected for divergent diferulate concentrations in pith stem tissues. Maize populations selected for high total diferulate concentration had 31% higher diferulates than those selected for low diferulates.

Dietary fiber supplementation for fecal incontinence: a randomized clinical trial.

Dietary fiber supplements are used to manage fecal incontinence (FI), but little is known about the fiber type to recommend or the level of effectiveness of such supplements, which appears related to the fermentability of the fiber. The aim of this single-blind, randomized controlled trial was to compare the effects of three dietary fiber supplements (carboxymethylcellulose [CMC], gum arabic [GA], or psyllium) with differing levels of fermentability to a placebo in community-living individuals incontinent of loose/liquid feces. The primary outcome was FI frequency; secondary outcomes included FI amount and consistency, supplement intolerance, and quality of life (QoL).

In vitro degradation and fermentation of three dietary fiber sources by human colonic bacteria.

Although clinical benefits of dietary fiber supplementation seem to depend partially on the extent of fiber degradation and fermentation by colonic bacteria, little is known about the effect of supplemental fiber type on bacterial metabolism. In an experiment using a nonadapted human bacterial population from three normal subjects, the extent of in vitro fermentation was greater for gum arabic (GA) than for psyllium (PSY), which was greater than that for carboxymethylcellulose (CMC). In a separate experiment, in vitro incubation with feces from 52 subjects with fecal incontinence, before and after random assignment to and consumption of one of three fiber (GA, PSY, or CMC) supplements or a placebo for 20-21 days, indicated that prior consumption of a specific fiber source did not increase its degradation by fecal bacteria.

Divergent selection for ester-linked diferulates in maize pith stalk tissues. Effects on cell wall composition and degradability.

Cross-linking of grass cell wall components through diferulates (DFAs) has a marked impact on cell wall properties. However, results of genetic selection for DFA concentration have not been reported for any grass species. We report here the results of direct selection for ester-linked DFA concentration in maize stalk pith tissues and the associated changes in cell wall composition and biodegradability.

Modifying crops to increase cell wall digestibility.

Improving digestibility of roughage cell walls will improve ruminant animal performance and reduce loss of nutrients to the environment. The main digestibility impediment for dicotyledonous plants is highly lignified secondary cell walls, notably in stem secondary xylem, which become almost non-digestible. Digestibility of grasses is slowed severely by lignification of most tissues, but these cell walls remain largely digestible.

Symptoms associated with dietary fiber supplementation over time in individuals with fecal incontinence.

Background: Knowledge about adverse symptoms over time from fiber supplementation is lacking.

Purpose: The aim of this study was to compare the severity of adverse gastrointestinal (GI) symptoms during supplementation with dietary fiber or placebo over time in adults with fecal incontinence. A secondary aim was to determine the relationship between symptom severity and emotional upset and their association with study attrition and reducing fiber dose.

Using RNA-Seq for gene identification, polymorphism detection and transcript profiling in two alfalfa genotypes with divergent cell wall composition in stems.

Background: Alfalfa, [Medicago sativa (L.) sativa], a widely-grown perennial forage has potential for development as a cellulosic ethanol feedstock. However, the genomics of alfalfa, a non-model species, is still in its infancy.

Cell wall composition as a maize defense mechanism against corn borers.

European and Mediterranean corn borers are two of the most economically important insect pests of maize (Zea mays L.) in North America and southern Europe, respectively. Cell wall structure and composition were evaluated in pith and rind tissues of resistant and susceptible inbred lines as possible corn borer resistance traits.

Comparing community and specialty provider-based recruitment in a randomized clinical trial: clinical trial in fecal incontinence.

Recruitment of participants to clinical trials remains a significant challenge, especially for research addressing topics of a sensitive nature such as fecal incontinence (FI). In the Fiber Study, a randomized controlled trial on symptom management for FI, we successfully enrolled 189 community-living adults through collaborations with specialty-based and community-based settings, each employing methods tailored to the organizational characteristics of their site. Results show that using the two settings increased racial and ethnic diversity of the sample and inclusion of informal caregivers.

Transcript profiling of two alfalfa genotypes with contrasting cell wall composition in stems using a cross-species platform: optimizing analysis by masking biased probes.

Background: The GeneChip(R) Medicago Genome Array, developed for Medicago truncatula, is a suitable platform for transcript profiling in tetraploid alfalfa [Medicago sativa (L.) subsp. sativa].

Optimizing on-farm pretreatment of perennial grasses for fuel ethanol production.

Switchgrass (Panicum virgatum L.) and reed canarygrass (Phalaris arundinacea L.) were pretreated under ambient temperature and pressure with sulfuric acid and calcium hydroxide in separate experiments.

Comment on "Carbon-negative biofuels from low-input high-diversity grassland biomass".

Tilman et al. (Reports, 8 December 2006, p. 1598) argued that low-input high-diversity grasslands can provide a substantial proportion of global energy needs.

UDP-sugar pyrophosphorylase is essential for pollen development in Arabidopsis.

Arabidopsis UDP-sugar pyrophosphorylase (AtUSP) is a broad substrate enzyme that synthesizes nucleotide sugars. The products of the AtUSP reaction can act as precursors for the synthesis of glycolipids, glycoproteins, and cell wall components including pectin and hemicellulose. AtUSP has no close homologs in Arabidopsis and its biological function has not been clearly defined.

Expression of UDP-glucose dehydrogenase reduces cell-wall polysaccharide concentration and increases xylose content in alfalfa stems.

The primary cell-wall matrix of most higher plants is composed of large amounts of uronic acids, primarily D-galacturonic acid residues in the backbone of pectic polysaccharides. Uridine diphosphate (UDP)-glucose dehydrogenase is a key enzyme in the biosynthesis of uronic acids. We produced transgenic alfalfa (Medicago sativa) plants expressing a soybean UDP-glucose dehydrogenase cDNA under the control of two promoters active in alfalfa vascular tissues.

Maize stem tissues: ferulate deposition in developing internode cell walls.

It has been hypothesized that ferulates are only deposited in the primary cell wall of grasses. To test this hypothesis, the fourth elongating, above-ground internode of maize (Zea mays l.) was sampled from three maize hybrids throughout development.