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.     

Detection of mitogen induced stimulation of leukocytes from the rainbow trout (Oncorhynchus mykiss) by flow cytometric analysis of intracellular calcium

Flow cytometric analysis of the forward/side light scatter (FSC/SSC) of density gradient-separated head kidney cells of the rainbow trout revealed three distinctly separated populations, which we defined as population 1, 2 and 3. In spleen cells, populations 1 and 2 were also found, whereas population 3 was not detected. Further characterization regarding the surface Ig (sIg) revealed that population 2 of the head kidney and spleen contained 37.4 and 34.4% sIg⁺-cells, respectively. Incubation of the head kidney and spleen cells with different concentrations of concanavalin A (ConA), phytohemagglutinin (PHA) and [PWM] induced a pronounced intracellular calcium increase only in cells of population 2. This reaction was concentration dependent and caused by a release of intracellular Ca²⁺-stores. FMLP, a chemotactic peptide, had no effect on intracellular calcium response in all three populations. Similarly, the stimulation with PMA had no effect. This indicates that population 2 of the head kidney as well as the spleen is characterized by a high forward and low side light scatter and contains both subpopulation of lymphocytes, B- and T-cells. We demonstrated that the analysis of intracellular calcium increase due to mitogens is a suitable approach to identify lymphocytes in fish and enables further functional studies in these cells.     

Gene delivery with low molecular weight linear polyethylenimines

BACKGROUND: Linear polyethylenimine (LPEI) with a molecular weight (MW) of 22 kDa has been described as having a superior ability to induce gene transfer compared to its branched form. However, the transfection efficiency of the polymer cannot be enhanced beyond a certain limit due to cytotoxicity. We explored the potential of utilizing LPEIs with MWs ranging from 1.0 to 9.5 kDa to overcome this limitation. METHODS: Polyplexes of plasmid DNA encoding for the enhanced green fluorescent protein (EGFP) and various LPEIs were compared concerning their transfection efficiency and cytotoxicity in CHO-K1 and HeLa cells by flow cytometry. The involvement of endolysosomes in LPEI-mediated gene transfer was investigated by applying the proton pump inhibitor bafilomycin A1 and the lysosomotropic agent sucrose. Confocal laser scanning microscopy was applied to assess the size and shape of polyplexes under cell culture conditions, to detect their endolysosomal localization and to observe their translocation to the nucleus. RESULTS: The transfection efficiency could be altered by varying the MW and the amount of the polymer available for polyplex formation. The highest transfection efficiency (about 44%), i.e. the fraction of EGFP-positive cells, was obtained with LPEI 5.6 kDa, while the cytotoxicity remained low. The colocalization of polyplexes and endolysosomes was observed, and it appeared that the larger polyplexes escaped from the acidic organelles particularly quickly. For LPEI 5.0 and 9.0 kDa, the number of cells and nuclei that had taken up DNA after 6 hours was similar, as determined by flow cytometry. CONCLUSIONS: Our study suggests that LPEIs with low MWs are promising candidates for non-viral gene delivery, because they are more efficient and substantially less toxic than their higher MW counterparts.     

Generation of mature fat pads in vitro and in vivo utilizing 3-D long-term culture of 3T3-L1 preadipocytes

Tissue-inherent factors such as cell-cell and cell-extracellular matrix interactions are regarded to exert a potentially large impact on adipogenesis as well as on secretory functions of adipose tissue. However, an appropriate 3-D adipogenesis model useful for addressing such interactions is still lacking. In this study, using tissue-engineering techniques, we demonstrate for the first time the development of coherent fat pads consisting of unilocular signet-ring cells in vitro. The constructs were generated by differentiating 3T3-L1 preadipocytes on 3-D polymeric scaffolds for either 9, 21, or 35 days in vitro. Only long-term culture yielded uniform tissues histologically comparable to native fat. Light and scanning electron microscopy provided direct evidence of 3-D tissue coherence and cell-cell contact in a tissue context, which was in strong contrast to conventional 2-D monolayer culture. Further differences between the two culture systems included enhanced secretion of leptin in 3-D tissue culture and differences in laminin expression (mRNA and protein level). Increase of triglyceride content over culture time and mRNA expression of other adipocyte genes, such as PPARgamma and Glut-4, were found to be similar. Implantation of long-term differentiated tissue constructs in nude mice resulted in further development and maintenance of fat pads. The presented model system is suggested to contribute to a better understanding of adipose tissue development and function facilitating studies on tissue-inherent interactions in vitro and in vivo.     

Photochemistry of allyloxybenzophenones: a pseudo-Paternò-Büchi rearrangement accompanied by hydrogen transfer induced 1,5-cyclization.

The solution photochemistry of the ortho allyloxy-substituted benzophenone has been investigated in detail. Product analysis revealed formation of a diastereomeric mixture of dihydrobenzofuran derivatives by cyclization via a short-lived intermediate 1,5-biradical and an unusual acetal by a pseudo-Paternò-Büchi rearrangement. The latter reaction pathway was supported by means of laser flash photolysis, where a long-lived intermediate with a maximum absorption band at 380 nm was observed. Besides, theoretical calculations (TD-DFT) of this UV-transient resulted in a band with maximum intensity at 390 nm showing a good correlation between experimental results and theoretical calculations. For comparison, the meta-substituent substrate was also investigated showing preferred triplet-triplet energy transfer.     

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).