Genetic control of rhizosheath formation in pearl millet

The rhizosheath, the layer of soil that adheres strongly to roots, influences water and nutrients acquisition. Pearl millet is a cereal crop that plays a major role for food security in arid regions of sub-Saharan Africa and India. We previously showed that root-adhering soil mass is a heritable trait in pearl millet and that it correlates with changes in rhizosphere microbiota structure and functions. Here, we studied the correlation between root-adhering soil mass and root hair development, root architecture, and symbiosis with arbuscular mycorrhizal fungi and we analysed the genetic control of this trait using genome wide association (GWAS) combined with bulk segregant analysis and gene expression studies. Root-adhering soil mass was weakly correlated only to root hairs traits in pearl millet. Twelve QTLs for rhizosheath formation were identified by GWAS. Bulk segregant analysis on a biparental population validated five of these QTLs. Combining genetics with a comparison of global gene expression in the root tip of contrasted inbred lines revealed candidate genes that might control rhizosheath formation in pearl millet. Our study indicates that rhizosheath formation is under complex genetic control in pearl millet and suggests that it is mainly regulated by root exudation.

[Patient with postpartum seizures: differential diagnosis]

Pre-eclampsia is a serious obstetric complication associated with a high rate of maternal and fetal morbidity and mortality. We report the case of a woman with a medical history of insulin-dependent diabetes mellitus and seizures possibly related to hypoglycemia who was admitted for an emergency cesarian due to severe pre-eclampsia and macrosomic fetus. In the first hour after delivery she experienced loss of consciousness and seizure, with vaginal bleeding and hypovolemic shock. Maximum vigilance is required for a patient with several concomitant diseases and a high-risk pregnancy. All prophylactic measures to lower the risk to mother and fetus should be undertaken. We analyze preanesthetic assessment, differential diagnosis, and choice of anesthesia in relation to this case.

Functional characterisation of Nicotiana tabacum xyloglucan endotransglycosylase (NtXET-1): generation of transgenic tobacco plants and changes in cell wall xyloglucan

To study the function of xyloglucan endotransglycosylase (XET) in vivo we isolated, a tomato (Lycopersicon esculentum Mill.) XET cDNA (GenBank AA824986) from the homologous tobacco (Nicotiana tabacum L.) clone named NtXET-1 (Accession no. D86730). The expression pattern revealed highest levels of NtXET-1 mRNA in organs highly enriched in vascular tissue. The levels of NtXET-1 mRNA decreased in midribs with increasing age of leaves. Increasing leaf age was correlated with an increase in the average molecular weight (MW) of xyloglucan (XG) and a decrease in the relative growth rates of leaves. Transgenic tobacco plants with reduced levels of XET activity were created to further study the biochemical consequences of reduced levels of NtXET-1 expression. In two independent lines, total XET activity could be reduced by 56% and 37%, respectively, in midribs of tobacco plants transformed with an antisense construct. The decreased activity led to an increase in the average MW of XG by at least 20%. These two lines of evidence argue for NtXET-1 being involved in the incorporation of small XG molecules into the cell wall by transglycosylation. Reducing the incorporation of small XG molecules will result in a shift towards a higher average MW. The observed reduction in NtXET-1 expression and increase in the MW of XG in older leaves might be associated with strengthening of cell walls by reduced turnover and hydrolysis of XG.

Distribution of lymphocyte surface antigens in healthy neonates

Using flow cytometric analysis we investigated the distribution of major lymphocyte surface antigens in newborn infants. A total of 221 newborns entered the study, of whom 53 fulfilled our criteria of healthy mature neonates. Percentages of immunofluorescent-positive cells were as follows (median and range from 25th to 75th percentiles given): for CD1 3.8%; 2.3%-5.8%. CD2 60.9%; 52.4%-66.8%. CD3 57.5%; 50.5%-63.3%. TcRass 57.7%; 48.1%-60.0%. CD4 36.3%; 28.0%-42.6%. CD8 23.0%; 20.0%-27.4%. CD11a 56.3%; 46.3%-68.5%. CD19 12.1%; 8.6%-14.8%. CD20 10.9%; 8.4%-12.9%. CD25 2.6%; 2.1%-4.5%. CDw52 61.0%; 51.2%-76.1%. CD71 5.2%; 3.1%-9.3%. While the ranges for the percentage of immunofluorescent-positive cells were rather small, there was a wide variation in the absolute numbers of marker immunofluorescent-positive cells.

[Simultaneous double fluorescence flow cytometry of lysed whole blood for prenatal diagnosis of combined immunodeficiency]

Simultaneous two-color flow cytometry of lysed whole blood allows the collection of maximal information from minimal blood volumes. This method was used for prenatal diagnosis of severe combined immunodeficiency by analysis of fetal blood. The data demonstrate that flow cytometry of lysed whole blood provides a reliable tool for prenatal diagnosis of certain immunodeficiencies. Moreover, the method described seems highly suitable for immunological monitoring of preterm infants and newborns. To enable the diagnosis of more subtle immunodeficiency states in these patients, however, valid normal values for all investigated parameters need to be defined first for the respective age/weight groups.