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.     

Mapping the distribution of the interstitial telomeric (TTAGGG)n sequences in eight species of Brazilian marsupials (Didelphidae) by FISH and the correlation with constitutive heterochromatin. Do ITS represent evidence for fusion events in American marsupials?

The C-band pattern and the distribution of the (TTAGGG)(n) sequence after fluorescence in situ hybridization (FISH), were studied in eight species of Didelphidae marsupials: four species with 2n = 14 (Marmosops parvidens, Marmosops incanus, Marmosa murina and Metachirus nudicaudatus), two species with 2n = 18 (Monodelphis domestica and M. americana), and two with 2n = 22 (Didelphis marsupialis and Lutreolina crassicaudata). The hybridization signals were observed at both termini telomeres of all chromosomes. In addition, interstitial sequences were detected in the pericentromeric region of all chromosomes of Marmosops parvidens, in five chromosome pairs of M. incanus, and in the first pair of Monodelphis domestica. These sites always occur in the region of constitutive heterochromatin, even though C-band positive regions do not always present interstitial telomeric sequences (ITS). We suggest that the interstitial (TTAGGG)(n) sequences are associated with satellite DNA and do not necessarily arise through chromosomal rearrangements.     

The Chehr Abad "Salt men" and the isotopic ecology of humans in ancient Iran

We have carried out isotopic analysis (δ(13)C and δ(15)N) on five salt-preserved bodies from the salt mine at Chehr Abad, Iran, dating from the 4th C. BC through to the 4th C. AD. In an attempt to identify the geographical origins of these people, we have analyzed over a hundred archeological bone samples from various archeological sites in Iran. From the faunal remains, we observe that the entire ecosystem appears to be enriched in (15)N, which we suggest is due to the semi-arid nature of the region. We have also observed a number of cattle remains from one site (Nargas Tepe) which have a significant C(4) component to their diet from the 4th millennium BC. By combining our data with those published by [Bocherens et al.: Environ Archaeol 5 (2000) 1-19; Bocherens et al.: J Arch Sci 33 (2006) 253-264], we suggest that two of the "mummies" may have come from the Tehran/Qazvin Plain region (i.e., relatively local to the salt mine), and a further two appear on isotopic grounds to have come from the northeast of Iran or the Turkmenistan steppes. The fifth (no. 4), the best preserved, appears to have come from further afield. Collectively, these mummies and their contexts augment our knowledge of social mobility and technical innovation in Iran during the Achaemenid period.     

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).     

Oldest Evidence of Toolmaking Hominins in a Grassland-Dominated Ecosystem

Background

Major biological and cultural innovations in late Pliocene hominin evolution are frequently linked to the spread or fluctuating presence of C₄ grass in African ecosystems. Whereas the deep sea record of global climatic change provides indirect evidence for an increase in C₄ vegetation with a shift towards a cooler, drier and more variable global climatic regime beginning approximately 3 million years ago (Ma), evidence for grassland-dominated ecosystems in continental Africa and hominin activities within such ecosystems have been lacking.

Methodology/Principal Findings

We report stable isotopic analyses of pedogenic carbonates and ungulate enamel, as well as faunal data from ∼2.0 Ma archeological occurrences at Kanjera South, Kenya. These document repeated hominin activities within a grassland-dominated ecosystem.

Conclusions/Significance

These data demonstrate what hitherto had been speculated based on indirect evidence: that grassland-dominated ecosystems did in fact exist during the Plio-Pleistocene, and that early Homo was active in open settings. Comparison with other Oldowan occurrences indicates that by 2.0 Ma hominins, almost certainly of the genus Homo, used a broad spectrum of habitats in East Africa, from open grassland to riparian forest. This strongly contrasts with the habitat usage of Australopithecus, and may signal an important shift in hominin landscape usage.     

Mitochondrial DNA phylogeography reveals marked population structure in the common vampire bat, Desmodus rotundus (Phyllostomidae)

Desmodus rotundus (Chiroptera: Phyllostomidae; Desmodontinae) is the most common vampire bat and has a broad distribution, ranging from southern Mexico to central Chile in the west, and Paraguay and northern Argentina in the east of South America ( Koopman 1988 ). Because of its feeding habit, this bat is considered the main source of rabies transmission to cattle. Although this species has a large spectrum of morphological variability throughout its range, thus far no study has examined the distribution of genetic lineages over its geographic range. Four geographically circumscribed clades of D. rotundus were described in the Brazilian territory on the basis of mitochondrial sequence analyses: southern Atlantic forest (SAF), northern Atlantic forest (NAF), Pantanal (PAN) and Amazon plus Cerrado (AMC) clade. The differentiation among these clades is strongly supported statistically, although the phylogenetic relationship between them remains uncertain. The extremely high levels of sequence divergence that were found between clades (ranging from 6% to 11%) are the highest ever described for a Neotropical bat species and cannot be explained by female philopatry alone. This indicates that D. rotundus comprises two or more distinct, possibly cryptic species. The biogeographic pattern described for this bat is similar to those described for other bats and terrestrial mammals, suggesting geographical congruence between historical vicariant processes, including likely vicariant events between north and south Atlantic Forest and between the Atlantic Forest and the Amazon.