Ligation of CR1 (C3b receptor, CD35) on CD4+ T lymphocytes enhances viral replication in HIV-infected cells

The present study provides evidence for a role of the C3b receptor, CR1 (CD35), in activation of HIV replication in CD4+ T lymphocytes. Ligation of CR1 with cross-linked anti-receptor MoAbs or with aggregated C3b enhanced transcription of viral genes and the release of p24 and RT activity from cultures of purified normal CD4+ T lymphocytes that had been infected with HIV-1 in vitro. No effect was observed upon ligation of CR2 (CD21), a C3 receptor that is also expressed on human CD4+ T cells. Cross-linking of CR1 also enhanced HIV replication in peripheral blood CD4+ lymphocytes isolated from HIV+ individuals. The enhancing effect of CR1 was not related to a mitogenic effect induced by stimulation of the receptor on T cells. The CR1 specificity of the enhancing effect was established by the observation that the addition of soluble recombinant CR1 to the cultures abolished the enhancement of p24 release induced by anti-CR1 MoAbs. Our results suggest that HIV replication may be triggered in resting HIV-infected CD4+ T lymphocytes through interaction with C3b-bearing immune complexes or particles

Synthesis of graphene by cobalt-catalyzed decomposition of methane in plasma-enhanced CVD: Optimization of experimental parameters with Taguchi method

This article describes the significant roles of process parameters in the deposition of graphene films via cobalt-catalyzed decomposition of methane diluted in hydrogen using plasma-enhanced chemical vapor deposition (PECVD). The influence of growth temperature (700–850 °C), molar concentration of methane (2%–20%), growth time (30–90 s), and microwave power (300–400 W) on graphene thickness and defect density is investigated using Taguchi method which enables reaching the optimal parameter settings by performing reduced number of experiments. Growth temperature is found to be the most influential parameter in minimizing the number of graphene layers, whereas microwave power has the second largest effect on crystalline quality and minor role on thickness of graphene films. The structural properties of PECVD graphene obtained with optimized synthesis conditions are investigated with Raman spectroscopy and corroborated with atomic-scale characterization performed by high-resolution transmission electron microscopy and scanning tunneling microscopy, which reveals formation of continuous film consisting of 2–7 high quality graphene layers

Seasonal variations in the diet and food selection of the Algerian hedgehog Atelerix algirus

International audienceThe Algerian hedgehog Atelerix algirus is an insectivorous species. However, the exact composition of its naturaldiet remains largely undetermined, especially in relation to seasonal variations in food availability. From Marchto November, we simultaneously analysed the composition of 180 hedgehog faecal samples and food availabilityin the Soumman Valley, Algeria to assess food selection in this species. The faeces contained 196 differentprey species, of which 92% belonged to the class Insecta. The highest prey species diversity was found in theColeoptera order (100 species recorded) and the highest species occurrence was found in Hymenoptera (65% of theprey items, mainly represented by the harvester ant Messor barbarus, a crop-ravaging species). This study showsthat the Algerian hedgehog is mainly a generalist species with a diet that is strongly linked to food availability.However, seasonal variations were observed in prey selection, and a notable shift in food preference was observedduring autumn. The exact nature of these changes in feeding behaviour remains to be investigated, notably inrelation to changes in energy requirements of this species before hibernation, in terms of quantity and/or quality