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J C Reeves

Publications and source records attributed to J C Reeves.

9 recordsLinked to original sources
PubMed2002

Temporal flux in the morphological and molecular diversity of UK barley.

Genetic-diversity assessments, using both phenotypic and molecular-marker data, were made on a collection of 134 barley varieties (both winter and spring types), chosen on the basis of their representation on the NIAB "Recommended List" over the period 1925-1995. Genotypic (AFLP and SSR) and phenotypic (UPOV characters) data were analysed to determine short- and long-term temporal trends in diversity over the period. A consistent pattern emerged demonstrating that only a minor proportion of the overall variance appears to be the result of any temporal drift, although there were strong indications of qualitative shifts in diversity, probably related to the changing relative acreage of winter and spring barleys over the study period. Our overall conclusions are that systematic plant breeding does not inevitably lead to a reduction in the genetic diversity of agricultural crops, and that diverse breeding programmes and the variety delivery systems in place in the UK have generally been successful in maintaining sufficient genetic diversity to allow the steady rise in genetic potential that has been a feature of 20th century crop breeding. The concentration of breeding effort into a smaller number of independent programmes is likely to be prejudicial to the maintenance of the genetic diversity of a crop.

Alleles↗
PubMed1996

DNA profiling and plant variety registration: 1. The use of random amplified DNA polymorphisms to discriminate between varieties of oilseed rape.

Before they can be marketed in the UK, newly bred varieties of crop species have to undergo a process of statutory testing, part of which involves the examination of the distinctness, uniformity and stability (DUS) of the variety. DUS testing is also used as the basis for the award of Plant Breeders' Rights. This paper examines the potential of DNA polymorphisms, amplified using arbitrary primers (RAPDs) for use in DUS testing of varieties of oilseed rape. RAPDs using suitable primers can produce high levels of discrimination (> 95%) between varieties, although there are certain problems in gel 'scoring' that are only partially resolved by computerised gel scanning/evaluation techniques. Varieties of oilseed rape are also heterogeneous in their RAPD profiles using certain primers, which could cause problems in the DUS testing context. DNA profiling with RAPDs could be used for discrimination between and identification of oilseed rape varieties, but its use for DUS testing needs to be considered carefully.

Base Sequence↗
PubMed1987

Antioxidant properties of 2-imidazolones and 2-imidazolthiones.

Uric acid has been postulated to be an important antioxidant and free radical scavenger in humans. Other purines, such as xanthine, that lack an 8-oxo group on the imidazole ring do not show antioxidant properties. For this reason, the antioxidative activities of 2-imidazolones and 2-imidazolthiones were compared to that of uric acid. 2-Imidazolthiones reacted with the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) at rates comparable to those of uric acid and other antioxidants. 2-Imidazolones also reacted with DPPH, although at a much slower rate than the 2-imidazolthiones. The 2-imidazolthiones protected oxyhemoglobin from oxidation to methemoglobin by sodium nitrite; the 2-imidazolones had little effect on the oxidation of oxyhemoglobin by nitrate. Most of the 2-imidazolthiones and 2-imidazolones protected both porcine and bovine erythrocytes from hemolysis by t-butyl hydroperoxide. Although 2-imidazolthiones were more reactive than 2-imidazolones in the assays using DPPH and the oxidation of oxyhemoglobin, both types of compounds may be useful as antioxidants in vivo.

Animals↗
PubMed1987

Attention deficit, conduct, oppositional, and anxiety disorders in children: III. Laboratory differences.

Children aged 5-13 years with DSM-III diagnoses of Attention Deficit (ADDH), Anxiety, (ANX), or Conduct plus ADDH (HC) Disorder and matched normal controls were compared on a set of laboratory measures of impulsivity, arousal, motor performance, activity level, and cognition, and on behavior ratings during testing. While ANX patients did not differ from their controls, ADDH and HC patients did on Verbal IQ, most of the behavior ratings, and on about one-third of the test variables. ANX patients were about 1 year older, and more likely to be female, than ADDH and HC patients. When age, sex, and verbal IQ effects were partialed out, very few differences among the three diagnostic groups remained. The importance of precise control of such variables is emphasized and the impact of the failure to do so in past studies is discussed. The question is raised whether the deficit in verbal IQ is not so much a defect of matching as the essential feature of ADDH from which most of the other commonly reported cognitive symptoms stem.

Adolescent↗
PubMed1985

Parasuicide and depression: a comparison of clinical and questionnaire diagnoses.

The frequency with which depressive disorder is diagnosed in parasuicide varies. It has been suggested that when observer bias is removed and a depression questionnaire employed, a greater number of young women who attempt suicide will be designated as depressed than would be expected on the basis of previous clinical reports. Our study compared clinical diagnoses made according to Feighner's research diagnostic criteria or DSM III with the categorisations obtained by the Levine-Pilowsky Depression questionnaire (LPD). Fifty-one patients, 34 female and 17 male, were studied, 31.4% having a primary Major Depressive Disorder and 23.5% secondary depression as clinical diagnoses. The LPD categorised 72.5% as depressed. Comparison of the clinical diagnoses with questionnaire data suggests that the LPD is overinclusive and not as specific as clinical diagnosis. Alcohol and substance abuse disorders accounted for almost one-third of the diagnoses and are therefore an important concomitant of parasuicide.

Adolescent↗