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.     

Feeding ecology of mackerel and dietary overlap with herring in Icelandic waters

The Northeast Atlantic mackerel (Scomber scombrus) has been extending its summer feeding distribution north and west, including around Iceland, since around 2006. The objective of this study is to quantify the weight gain and total food consumption of mackerel and to evaluate the food competition between mackerel and herring (Clupea harengus) feeding in the marine ecosystem around Iceland during the summers 2009–2011. Mackerel feeding in Icelandic waters gained around 43% on average in weight during these summers. Based on swept-area abundance estimates of mackerel from an international survey in 2011 and available estimates of food conversion efficiency in mackerel, the weight gain in Icelandic waters in 2011 corresponded to a total consumption of around 3.4 (2.4?4.5) million tonnes. Overall, 98% of 2314 mackerel, 91% of 398 Icelandic summer-spawning herring and 96% of 424 Norwegian spring-spawning herring stomachs, collected over the summers 2009?2011, contained food. The mean weight of the stomach content of mackerel was higher than for herring in all the years. While the stomach content weight of mackerel was generally highest in southeastern and southwestern areas, it was highest for herring in western, eastern and northern areas. Analysis of stomach contents showed that Copepoda were the most important food of mackerel in most areas, while Copepoda and Euphausiacea were the most important food items for herring. Fish prey contributed a higher proportion in stomachs of mackerel than herring, although relatively low for both species.     

Hydrolysis rates of 1-glucosyl-2-benzoylhydrazines in aqueous solution

A series of substituted 1-glucosyl-2-benzoylhydrazines were synthesized and their pseudo-first-order rate constants for hydrolysis were determined at pH 4, 5, 6 at 50 degrees C. All the compounds hydrolyzed quickly (t(1/2)<3h) at pH 4.0, but were increasingly stable as the pH approached neutrality.     

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.     

The diversity of Listeria monocytogenes strains from 10 Icelandic sheep farms

AIMS: The purpose of this study was to examine the diversity of Listeria monocytogenes strains from healthy sheep, winter feed and environment of sheep farms in Iceland. METHODS AND RESULTS: A total of 104 L. monocytogenes isolates from animals, winter feed and environment on 10 Icelandic sheep farms were compared by serotyping, ribotyping, and pulsed-field gel electrophoresis with ApaI and AscI. The isolates were divided into 24 genotypes, all identified as serovars 1/2a, 1/2b, or 4b. Nine genotypes were detected on more than one farm. On three of the farms there seemed to be a dominant strain of L. monocytogenes. Isolates from incidents of listeriosis in animals occurring on two of the farms belonged to the genotype most commonly found on the particular farm. Nine of the 24 genotypes found on the sheep farms have been associated with disease in animals and/or humans elsewhere in Iceland. CONCLUSIONS: Certain strains of L. monocytogenes seem to be widely distributed on Icelandic sheep farms. On some farms there appears to be a dominant strain of L. monocytogenes. Incidents of listeriosis in animals may tend to be associated with strains commonly found on the farm. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates the diversity of L. monocytogenes present in healthy sheep and their environment.     

Characterization of cold-adapted Atlantic cod (Gadus morhua) trypsin I — Kinetic parameters,autolysis and thermal stability

Atlantic cod trypsin I is a highly active cold-adapted protease. This study aimed at further characterization of this enzyme with respect to kinetic parameters, sites of autolysis and stability. For that purpose, trypsin I was purified by anion exchange chromatography. Its purity and identity was verified by SDS-PAGE analysis and mass spectrometry. Concomitantly, another cod trypsin isozyme, trypsin X, previously only described from its cDNA sequence was detected in a separate peak from the ion exchange chromatogram. There was a stepwise increase in the catalytic efficiency (k_cat/K_m) of cod trypsin I obtained with substrates containing one to three amino acid residues. As expected, the activity of trypsin I was maintained for longer periods of time at 15 °C than at higher temperatures. The residues of the trypsin I molecule most sensitive to autolysis were identified using Edman degradation. Eleven autolytic cleavage sites were detected within the trypsin I molecule. Unfolding experiments demonstrated that autolysis is a contributing factor in the stability of trypsin I. In addition, the data shows that cod trypsin I is less stable towards thermal unfolding than its mesophilic bovine analogue.     

The effects of H-bonding and sterics on the photoreactivity of a trimethyl butyrophenone derivative

The irradiation of ester 1 in methanol and chloroform does not yield any photoproducts, whereas the photolysis of 1 in dry argon-saturated benzene produces cyclobutanol 4, which is converted to lactone 5 by the addition of HCl. Laser-flash photolysis of ester 1 demonstrates that 1 undergoes intramolecular H-atom abstraction to form the biradical 2 (λ(max)～ 310 nm, τ = 200 ns, benzene), which intersystem crosses to photoenols, Z-3 (λ(max)～ 380 nm, τ = 30-60 μs, benzene) and E-3 (λ(max)～ 380 nm, τ = 11 ms, benzene). Density functional theory calculations were performed to support the proposed mechanism for forming cyclobutanol 4 and to explain how steric demand facilitates photoenol E-3 to form cyclobutanol 4 rather than lactone 5.     

Altered binding and transport of vitamin B12 resulting from insertion mutations in the Escherichia coli btuB gene

The BtuB protein of Escherichia coli is a multifunctional outer membrane receptor required for the binding and uptake of vitamin B12, bacteriophage BF23, and the E colicins. The btuB gene was mutagenized by the insertion of 6-base pair linkers into each of ten HpaII sites distributed throughout the coding region. Receptor function was measured with the mutated genes present in single or multiple copies. All of the mutant proteins were found in the outer membrane in similar amounts, although two of them were susceptible to cleavage by endogenous proteolytic activity. The vitamin B12 transport activity mediated by five of the mutants was essentially identical to that of the wild type. Four mutations (insertions after amino acids 50, 252, and 412, and a duplication of residues 434-472) reduced uptake activity to less than 2% of parental, whereas insertions at residues 343 and 434 had less severe effect. The insertions at residues 50 and 252 appeared to slow the rate of cobalamin binding to the receptor; the defect in the former mutant was partially corrected by elevated calcium levels. The insertion at residue 412 did not affect the rate of substrate binding but slowed its release from the receptor. Most of the receptors conferred susceptibility to phage BF23 and the E colicins, although several mutants were altered in the degree of their sensitivity to the lethal agents. None of the mutations affected the entry of only one type of ligand. Thus, several receptor domains have been implicated in substrate binding and energy coupling.     

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).