Manipulation of defence related lignification in wheat

Lignin is a complex phenolic hetropolymer with an established role in structure, support and defence in higher plants. The chemical structure of lignin is as yet undefined but controlled by an enzymatic pathway leading to three monomeric subunits. Lignin accumulates in plants in response to pathogen challenge. A scanning densitrometric assay to detect lignin was developed that was non-invasive, quantitative and quick to perform. The assay was used in conjunction with assessments of phytotoxicity, mycotoxity and pathogen resistance to assess the efficacy of potential biochemical inhibitors of the phenylpropanoid pathway in vivo. With this information, tolerances for biochemical inhibition of the phenylpropanoid pathway were obtained. This allowed further investigation of the basis of genetic and metabolic regulation of one form of one enzyme of the pathway, phenylalanine ammonia lyase, in wheat. Evidence of a potential role for endogenous elicitation in the ligninification pathway was also gained by the use of the assay. Elicitation in terms of the hypersensitive response was also investigated during attempts to purify the fungal elicitor Avr2 using the tovnaXo!Cladosporium fulvum model; however this work was completed by an alternative genetic screen protocol published elsewhere. Control of ligninificiation and the enzymes that produce the polymer is therefore an essential part of the defence response in wheat. This has important implications for genetic modification of the pathway. It was shown in this study that the phenylpropanoid pathway controls one aspect of resistance in wheat and concludes that care must be taken when manipulating the pathway in plants for increased digestibility or ease of pulping. In addition, a separate project was undertaken in order to purify an avirulence protein possessed by the Cladosporiumfulvum fungus. The projects aim was to obtain amino acid sequence(s) of potential interacting proteins that would be used to design primer sequences to provide a genetic sequence of the target avirulence protein Avr2. Although several candidate proteins were obtained and amino acid sequencing attempted; a competing group obtained the genetic sequence of Avr2. The sequence of this clone predicts a protein whose molecular weight and isoelectric point falls within a region of proteins whose isoelectric points and molecular weights show activity in a bioassay for Cf-2 interacting proteins. This data supports the conclusion that the work by Luderer et al (2002) defines the genetic sequence of Avr 2

Theodicy and evolution: aspects of theology from Pierre Bayle to J.S. Mill

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Treatment for paediatric chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME) and comorbid depression:a systematic review

OBJECTIVES: At least 30% of young people with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) also have symptoms of depression. This systematic review aimed to establish which treatment approaches for depression are effective and whether comorbid depression mediates outcome. SETTING: A systematic review was undertaken. The search terms were entered into MEDLINE, EMBASE, PsycInfo and the Cochrane library. PARTICIPANTS: Inclusion and exclusion criteria were applied to identify relevant papers. Inclusion criteria were children age <18, with CFS/ME, defined using CDC, NICE or Oxford criteria, and having completed a valid assessment for depression. RESULTS: 9 studies were identified which met the inclusion criteria, but none specifically tested treatments for paediatric CFS/ME with depression and none stratified outcome for those who were depressed compared with those who were not depressed. There is no consistent treatment approach for children with CFS/ME and comorbid depression, although cognitive–behavioural therapy for CFS/ME and a multicomponent inpatient programme for CFS/ME have shown some promise in reducing depressive symptoms. An antiviral medication in a small scale, retrospective, uncontrolled study suggested possible benefit. CONCLUSIONS: It is not possible to determine what treatment approaches are effective for depression in paediatric CFS/ME, nor to determine the impact of depression on the outcome of CFS/ME treatment. Young people with significant depression tend to have been excluded from previous treatment studies