PubMed Health⌕ Search

Biomedical subjects

P W Sutherland

Publications and source records attributed to P W Sutherland.

10 recordsLinked to original sources
PubMed2004

Cytochemistry and immunolocalisation of polysaccharides and proteoglycans in the endosperm of green Arabica coffee beans.

The major noncellulosic polysaccharides and proteoglycans in the coffee bean (Coffea arabica) cell wall are (galacto)mannans and arabinogalactan proteins. Immunological and chemical probes demonstrated that the mannans and arabinogalactan proteins were located continuously across the width of the cell wall, but that the concentration of different structural epitopes within these polysaccharide types showed considerable spatial variation. For the mannans this was implied by the striated pattern demonstrated by fluctuation of the affinity between the mannan monoclonal antibody BGM C6 and (galacto)mannan. The arabinogalactan proteins labelled by the Yariv reagent and the arabinogalactan protein-specific antibody LM2 appeared to be located in all regions of the wall except the middle lamella, but showed some differences in intensity of labelling. However, the LM6 antibody, specific for (1-->5)-alpha-arabinan epitopes, was located only as a compact region adjacent to the cell lumen in the body of the endosperm; though, it did label throughout the wall of epidermal cells. This implied that either some of the more highly arabinosylated arabinogalactan proteins contained contiguous 5-arabinosyl residues or that a rhamnogalacturonan which contained 5-arabinosyl residues as side chains existed in the cell wall. In either case the polymers were very restricted in their distribution. A second category of pectin, a homogalacturonan detected by JIM7, was located only in the middle lamella region. The architecture of the wall, as revealed by resin etching, appeared to reflect the chemical heterogeneity, with three distinct physical zones identifiable in a cross section across a single wall.

Biopolymers↗
PubMed2003

Sieve element specific labeling with an anti-idiotypic monoclonal antibody mimic of the phytotoxin dothistromin.

A monoclonal antibody, 12C9, an anti-idiotypic mimic of dothistromin, a toxin produced by Dothistroma pini, was found to label the cell wall of sieve elements in a number of different plant tissues and species. The antibody labeled apple leaf tissue, tobacco leaf mid vein, leaf and meristem, and Coprosma robusta leaf mid vein. Labeling was restricted to cell walls of sieve elements and did not label the companion cells or the lumen of the cells. The antibody labeled over a wide range of dilutions. This antibody could be used to differentiate sieve elements from other types of phloem. It could also be used to co-localize sieve elements and microorganisms such as phytoplasmas stained with DAPI.

Anthraquinones↗
PubMed2001

Dark green islands in plant virus infection are the result of posttranscriptional gene silencing.

Dark green islands (DGIs) are a common symptom of plants systemically infected with a mosaic virus. DGIs are clusters of green leaf cells that are free of virus but surrounded by yellow, virus-infected tissue. We report here on two lines of evidence showing that DGIs are caused by posttranscriptional gene silencing (PTGS). First, transcripts of a transgene derived from the coat protein of Tamarillo mosaic potyvirus (TaMV) were reduced in DGIs relative to adjacent yellow tissues when the plants were infected with TaMV. Second, nontransgenic plants coinfected with TaMV and a heterologous virus vector carrying TaMV sequences showed reduced titers of the vector in DGIs compared with surrounding tissues. DGIs also were compared with recovered tissue at the top of transgenic plants because recovery has been shown previously to involve PTGS. Cytological analysis of the cells at the junction between recovered and infected tissue was undertaken. The interface between recovered and infected cells had very similar features to that surrounding DGIs. We conclude that DGIs and recovery are related phenomena, differing in their ability to amplify or transport the silencing signal.

Gene Silencing↗
PubMed1980

Cystic fibrosis and bronchial hyperreactivity. Concomitant defects or cause and effect?

Bronchial reactivity and lung-function tests were measured in 19 young adults with cystic fibrosis. There was moderately severe airways obstruction without hyperinflation, and mild hypoxaemia with normocapnia. Bronchial reactivity (fall in FEV1 after the administration of methacholine aerosol) was increased in about two-thirds of patients, and was markedly enhanced in nearly half of them. It was considered that the airways obstruction characteristic of cystic fibrosis can have a reversible element, and that this may provide a rationale for the use of bronchodilators in some patients. Although bronchial hyperreactivity in cystic fibrosis could represent concomitant underlying defects, a more attractive suggestion is that the chronic inflammation of cystic fibrosis has, in turn, led to acquired bronchial hyperreactivity.

Adolescent↗
PubMed1975

Goodpasture's syndrome: normal renal diagnostic findings.

A patient with Goodpasture's syndrome is described in whom pulmonary manifestations were dramatic, but in whom renal abnormalities were minor and only found on fluorescent and electron microscopy. His urine showed no proteinuria and no increase in cells in quantitative counts, and renal function was normal. It is suggested that there may be an indication for carrying out renal biopsies in patients with idiopathic pulmonary haemosiderosis and that this may lead to an early diagnosis of Goodpasture's syndrome.

Adolescent↗