Scanning electron microscopy of Meloidogyne incognita juveniles entrapped in maize roots by a nematode-trapping fungus Arthrobotrys dactyloides

During a study on the presence and location of Meloidogyne incognita race 2 within maize roots, a nematode-trapping fungus, Arthrobotrys dactyloides was observed for the first time on maize in South Africa

The genus Helicotylenchus in the grassland biome of South Africa

The genus Helicotylenchus is widespread in South Africa with 25 of the 33 Helicotylenchus species in the grassland biome. With 23 species reported from uncultivated areas, 14 species from crop plants and 10 species from the grasses grown on sports fields, Helicotylenchus is ideally suited for a study on the impact of cultivation on nematode diversity.This paper was initially delivered at the Annual Congress of the Biological Sciences Division of the South African Academy for Science and Art, ARC-Plant Protection Research Institute, Roodeplaat, Pretoria, South Africa on 01 October 2010.http://www.satnt.ac.zaam2014ab201

Serum magnesium and calcium levels in relation to ischemic stroke : Mendelian randomization study

ObjectiveTo determine whether serum magnesium and calcium concentrations are causally associated with ischemic stroke or any of its subtypes using the mendelian randomization approach.MethodsAnalyses were conducted using summary statistics data for 13 single-nucleotide polymorphisms robustly associated with serum magnesium (n = 6) or serum calcium (n = 7) concentrations. The corresponding data for ischemic stroke were obtained from the MEGASTROKE consortium (34,217 cases and 404,630 noncases).ResultsIn standard mendelian randomization analysis, the odds ratios for each 0.1 mmol/L (about 1 SD) increase in genetically predicted serum magnesium concentrations were 0.78 (95% confidence interval [CI] 0.69-0.89; p = 1.3 7 10-4) for all ischemic stroke, 0.63 (95% CI 0.50-0.80; p = 1.6 7 10-4) for cardioembolic stroke, and 0.60 (95% CI 0.44-0.82; p = 0.001) for large artery stroke; there was no association with small vessel stroke (odds ratio 0.90, 95% CI 0.67-1.20; p = 0.46). Only the association with cardioembolic stroke was robust in sensitivity analyses. There was no association of genetically predicted serum calcium concentrations with all ischemic stroke (per 0.5 mg/dL [about 1 SD] increase in serum calcium: odds ratio 1.03, 95% CI 0.88-1.21) or with any subtype.ConclusionsThis study found that genetically higher serum magnesium concentrations are associated with a reduced risk of cardioembolic stroke but found no significant association of genetically higher serum calcium concentrations with any ischemic stroke subtype

Plant nematodes in South Africa. 7. A check list of plant nematodes from the Fynbos Biome, with a description of <i>Helicotylenchus curatus</i> sp. n.

Plant nematodes recorded during surveys in the Fynbos Biome are listed and a new Helicotylenchus species is described. Helicotylenchus curatus sp. n. is characterised by stylet length (42-46 μm in females, 37-40 μm in males), presence of two rudimentary subdorsal and two rudimentary subventral lobes on the labial disc, first lip annulus divided into six sectors, presence of fasciculi and presence of males. Nine families represented by 32 genera and 152 species were identified from the Fynbos Biome. The genera Criconema, Helicotylenchus, Hemicycliophora, Rotylenchus, Scutellonema and Xiphinema were found in more than 30 % of the localities, whereas Caloosia, Criconemoides, Ditylenchus, Geocenamus, Hemicriconemoides, Heterodera, Hoplolaimus, Longidorus, Meloidogyne, Mesocriconema, Ogma, Paralongidorus, Paratrichodorus, Paratylenchus, Pratylenchoides, Pratylenchus, Rotylenchulus, Trichodorus and Tylenchorhynchus were found at fewer localities. The genera Anguina, Hirschmaniella, Histotylenchus and Zygotylenchus were each identified from a single locality