Permanent Genetic Resources added to Molecular Ecology Resources Database 1 April 2011-31 May 2011

This article documents the addition of 92 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Anopheles minimus, An. sinensis, An. dirus, Calephelis mutica, Lutjanus kasmira, Murella muralis and Orchestia montagui. These loci were cross-tested on the following species: Calephelis arizonensi, Calephelis borealis, Calephelis nemesis, Calephelis virginiensis and Lutjanus bengalensis.     

Structure and in vitro antitumor activity evaluation of brominated diterpenes from the red alga Sphaerococcus coronopifolius

A novel bromoditerpene methyl ketone (1), two new bromoditerpene alcohols featuring a neodolastane (2), and a bromocorodienol skeleton (3), along with 13 previously reported metabolites (4–16) were isolated from the organic extract of Sphaerococcus coronopifolius collected from the rocky coasts of Corfu island in the Ionian Sea. The structures of the new natural products, as well as their relative stereochemistry, were elaborated on the basis of extensive spectral analysis, including 2D NMR experiments. The absolute stereochemistry of metabolite 3 was determined using the modified Mosher’s method. The isolated metabolites were evaluated for their antitumoral activity against four human apoptosis-resistant (U373, A549, SKMEL-28, OE21) and two human apoptosis-sensitive (PC-3, LoVo) cancer cell lines with IC₅₀ in vitro growth inhibitory concentrations in the range 3–100 μM.     

Role of interferons in the control of Lassa virus replication in human dendritic cells and macrophages

Lassa fever is a hemorrhagic fever caused by Lassa virus (LV), which primarily targets human dendritic cells (DC) and macrophages (MP). Massive numbers of viral particles are released with no effect on the viability, activation or maturation of these cells. LV does not inhibit the activation of cells induced by sCD40L or LPS. We report here the consequences of exogenous activation of LV-infected human DC and MP for viral replication. The activation of cells with lipopolysaccharide or exogenous poly(I-C) and the transfection of cells with poly(I-C) strongly inhibited LV replication, at least partly by inducing type I interferon (IFN) synthesis. In contrast, cell stimulation with sCD40L did not induce type I IFN responses or inhibit LV release. Recombinant type I IFNs strongly inhibited LV replication in both cell types, whereas IFNgamma and IFNlambda did not. The modest type I IFN production observed in LV-infected MP, but not in DC, was involved in controlling LV replication in MP. These results provide an explanation for the slower replication of LV in MP than in DC, and suggest that type I IFNs are crucial in the control of LV.     

RRP1B targets PP1 to mammalian cell nucleoli and is associated with Pre-60S ribosomal subunits

A pool of protein phosphatase 1 (PP1) accumulates within nucleoli and accounts for a large fraction of the serine/threonine protein phosphatase activity in this subnuclear structure. Using a combination of fluorescence imaging with quantitative proteomics, we mapped the subnuclear localization of the three mammalian PP1 isoforms stably expressed as GFP-fusions in live cells and identified RRP1B as a novel nucleolar targeting subunit that shows a specificity for PP1β and PP1γ. RRP1B, one of two mammalian orthologues of the yeast Rrp1p protein, shows an RNAse-dependent localization to the granular component of the nucleolus and distributes in a similar manner throughout the cell cycle to proteins involved in later steps of rRNA processing. Quantitative proteomic analysis of complexes containing both RRP1B and PP1γ revealed enrichment of an overlapping subset of large (60S) ribosomal subunit proteins and pre-60S nonribosomal proteins involved in mid-late processing. Targeting of PP1 to this complex by RRP1B in mammalian cells is likely to contribute to modulation of ribosome biogenesis by mechanisms involving reversible phosphorylation events, thus playing a role in the rapid transduction of cellular signals that call for regulation of ribosome production in response to cellular stress and/or changes in growth conditions.     

Carbapenem-hydrolyzing GES-5-encoding gene on different plasmid types recovered from a bacterial community in a sewage treatment plant

Plasmids pRSB113 and pRSB115 were recovered from an activated sludge bacterial community of a municipal wastewater treatment plant in Germany. Both plasmids carry the same bla(GES-5) carbapenemase gene, located within two distinct class 1 integrons. These plasmids have different backbones, belong to different incompatibility groups, and could replicate in both Pseudomonas aeruginosa and Escherichia coli.     

Human dendritic cells infected with the nonpathogenic Mopeia virus induce stronger T-cell responses than those infected with Lassa virus

The events leading to death in severe cases of Lassa fever (LF) are unknown. Fatality seems to be linked to high viremia and immunosuppression, and cellular immunity, rather than neutralizing antibodies, appears to be essential for survival. We previously compared Lassa virus (LV) with its genetically close but nonpathogenic homolog Mopeia virus (MV), which was used to model nonfatal LF. We showed that strong and early activation of antigen-presenting cells (APC) may play a crucial role in controlling infection. Here we developed an in vitro model of dendritic-cell (DC)-T-cell coculture in order to characterize human T-cell responses induced by MV- or LV-infected DCs. Our results show very different responses to infection with LV and MV. MV strongly and durably stimulated CD8(+) and CD4(+) T cells, showing early and high activation, a strong proliferative response, and acquisition of effector and memory phenotypes. Furthermore, robust and functional CD4(+) and CD8(+) cytotoxic T lymphocytes (CTL) were generated. LV, however, induced only weak memory responses. Thus, this study allows an improved understanding of the pathogenesis and immune mechanisms involved in the control of human LV.