Effect of Metalaxyl on the incidence and severity of Pearl millet downy mildew disease in Northern Nigeria

Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight.     

Gene expression and the evolution of phenotypic diversity in social wasps

Background  

Organisms are capable of developing different phenotypes by altering the genes they express. This phenotypic plasticity provides a means for species to respond effectively to environmental conditions. One of the most dramatic examples of phenotypic plasticity occurs in the highly social hymenopteran insects (ants, social bees, and social wasps), where distinct castes and sexes all arise from the same genes. To elucidate how variation in patterns of gene expression affects phenotypic variation, we conducted a study to simultaneously address the influence of developmental stage, sex, and caste on patterns of gene expression in Vespula wasps. Furthermore, we compared the patterns found in this species to those found in other taxa in order to investigate how variation in gene expression leads to phenotypic evolution.     

Fluorometric quantification of RNA and DNA in solutions containing both nucleic acids

A fluorescence-based method for quantitative determination of RNA and DNA in probes containing both nucleic acids has been developed. The total concentration of nucleic acids is determined using SYBR Green II dye under conditions providing independent binding of the fluorophore with DNA and RNA. The concentration of DNA is specifically measured using the Hoechst 33258 dye and the RNA concentration is calculated from these data. The procedure allows for accurate determination of DNA concentration in the range 10-1000 ng/ml in the presence of 200-fold excess of RNA and determination of RNA concentrations in the range 10-1000 ng/ml in the presence of large excess of DNA. An absence of the treatment of mixed samples with RNase-free DNase I provides rapid, reproducible, and accurate RNA quantification.     

A comparative study of structural properties of fibronectin and its 180 kDa fragment

Fibronectin from human plasma and its 180 kDa fragment which retained collagen-binding, cell-attachment and heparin-binding activities, were studied by velocity centrifugation and 1H-NMR methods. The fibronectin hydrodynamic radius strongly increased at pH 11 while the hydrodynamic properties of the fragment did not change noticeably. 1H-NMR spectroscopy also showed differences in the molecular properties of fibronectin and its 180 kDa fragment. Under physiological conditions the structure of fibronectin differs from that of its 180 kDa fragment. At pH 11 and in 4 M urea no differences in their structures are observed. It is suggested that interdomain and intersubunit interactions play an important role in maintaining the native conformation of intact fibronectin.     

A randomised, blinded, placebo-controlled trial in dementia patients continuing or stopping neuroleptics (the DART-AD trial)

Background

There have been increasing concerns regarding the safety and efficacy of neuroleptics in people with dementia, but there are very few long-term trials to inform clinical practice. The aim of this study was to determine the impact of long-term treatment with neuroleptic agents upon global cognitive decline and neuropsychiatric symptoms in patients with Alzheimer disease.

Methods and Findings

Design: Randomised, blinded, placebo-controlled parallel two-group treatment discontinuation trial.Setting: Oxfordshire, Newcastle and Gateshead, London and Edinburgh, United Kingdom.Participants: Patients currently prescribed the neuroleptics thioridazine, chlorpromazine, haloperidol trifluoperazine or risperidone for behavioural or psychiatric disturbance in dementia for at least 3 mo.Interventions: Continue neuroleptic treatment for 12 mo or switch to an identical placebo.Outcome measures: Primary outcome was total Severe Impairment Battery (SIB) score. Neuropsychiatric symptoms were evaluated with the Neuropsychiatric Inventory (NPI).Results: 165 patients were randomised (83 to continue treatment and 82 to placebo, i.e., discontinue treatment), of whom 128 (78%) commenced treatment (64 continue/64 placebo). Of those, 26 were lost to follow-up (13 per arm), resulting in 51 patients per arm analysed for the primary outcome. There was no significant difference between the continue treatment and placebo groups in the estimated mean change in SIB scores between baseline and 6 mo; estimated mean difference in deterioration (favouring placebo) −0.4 (95% confidence interval [CI] −6.4 to 5.5), adjusted for baseline value (p = 0.9). For neuropsychiatric symptoms, there was no significant difference between the continue treatment and placebo groups (n = 56 and 53, respectively) in the estimated mean change in NPI scores between baseline and 6 mo; estimated mean difference in deterioration (favouring continue treatment) −2.4 (95% CI −8.2 to 3.5), adjusted for baseline value (p = 0.4). Both results became more pronounced at 12 mo. There was some evidence to suggest that those patients with initial NPI ≥ 15 benefited on neuropsychiatric symptoms from continuing treatment.

Conclusions

For most patients with AD, withdrawal of neuroleptics had no overall detrimental effect on functional and cognitive status. Neuroleptics may have some value in the maintenance treatment of more severe neuropsychiatric symptoms, but this benefit must be weighed against the side effects of therapy.Trial registration: Cochrane Central Registry of Controlled Trials/National Research Register (#ISRCTN33368770).     

Physico-chemical properties of low density lipoproteins isolated in an equilibrium density gradient

The tryptophanyls of total low density lipoproteins (LDL) (1.006-1.063 g/ml) from coronary heart disease (CHD) patients and subjects without CHD signs had different accessibility to fluorescence quenchers (I-and acrylamide). LDL were separated into subfractions in equilibrium density gradient. The coefficient of extinction , quantum yield and other spectral characteristics of LDL intrinsic fluorescence, rotational mobility of maleimide spin labels and fatty acid spin probe were different in LDL subfractions from healthy subjects. LDL subfractions with hydrated density 1.045-1.05 g/ml bound to B,E-receptors of cultured fibroblasts more effectively than did subfractions with density 1.01-1.03 g/ml. Structural differences of apo-B in the particles with different lipid to protein ratio are supposed.     

Ice premelting during differential scanning calorimetry

Premelting at the surface of ice crystals is caused by factors such as temperature, radius of curvature, and solute composition. When polycrystalline ice samples are warmed from well below the equilibrium melting point, surface melting may begin at temperatures as low as -15 degrees C. However, it has been reported (. Biophys. J. 65:1853-1865) that when polycrystalline ice was warmed in a differential scanning calorimetry (DSC) pan, melting began at about -50 degrees C, this extreme behavior being attributed to short-range forces. We show that there is no driving force for such premelting, and that for pure water samples in DSC pans curvature effects will cause premelting typically at just a few degrees below the equilibrium melting point. We also show that the rate of warming affects the slope of the DSC baseline and that this might be incorrectly interpreted as an endotherm. The work has consequences for DSC operators who use water as a standard in systems where subfreezing runs are important.