Structural characteristics of immunogenic liver-stage antigens derived from P. falciparum malarial proteins

A fully effective antimalarial vaccine must contain multiple proteins from the different development stages of Plasmodium falciparum parasites involved in host-cell invasion or their biologically active fragments. It must therefore include sporozoite molecules able to induce protective immunity by blocking the parasite’s access to hepatic cells, and/or proteins involved in the development of this stage, amongst which are included the Liver Stage Antigen-1 (LSA-1) and the Sporozoite and Liver Stage Antigen (SALSA).Our studies have focused on the search for an association between the structure of high activity binding peptides (HABPs), including both conserved native and their modified analogues, and their ability to bind to the MHC Class II HLA-DR molecules during formation of the MHCII-peptide-TCR complex leading to inducing the appropriate immune response. These studies are part of a logical and rational strategy for developing multi-stage, multi-component, minimal subunit-based vaccines, mainly against the P. falciparum malaria.     

Actividad antimicótica y citotóxica de aceites esenciales de plantas de la familia Asteraceae

BackgroundThe plants of the Asteraceae family have been used for medicinal purposes,in traditional Colombian medicine.AimTo evaluate the antifungal activity and the cytotoxic effects of 15 essential oils from plants of the Asteraceae family.MethodsAntifungal activity was evaluated against Candida parapsilosis ATCC 22019, Candida krusei ATCC 6258, Aspergillus flavus ATCC 204304 and Aspergillus fumigatus ATCC 204305 following EUCAST and CLSI M38-A standard methods, for yeast and filamentous fungi, respectively. Cytotoxic effect was evaluated on Vero cell line by MTT assay.ResultsThe oils from the plants Achyrocline alata and Baccharis latifolia were the only ones active against A. fumigatus (GM-MIC=78.7 and 157.4 μg/ml, respectively). In contrast, there was no evidence of oils active against Candida species. In addition, these oils were not cytotoxic on Vero cells. The oils of A. alata and Baccharis latifolia could be candidates for disinfecting hospital environments and for inhibiting biofilm formation by A. fumigatusConclusionsThe oils of A. alata and B. latifolia could be candidates for disinfecting hospital environments and for inhibiting biofilm formation by A. fumigatus     

Sensitivity of different taxonomic levels of soil Gamasina to land use and anthropogenic disturbances

• 1 The effect of taxonomic level on the sensitivity of bioindicators has been widely investigated in aquatic ecosystems and, to a lesser extent, in terrestrial ecosystems. However, no studies have been conducted on the sensitivity of the different taxonomic levels of soil mites, especially Gamasina, to human activities.
• 2 The present study aimed to assess the sensitivity of different taxonomic levels of soil Gamasina mites to anthropogenic disturbances in Europe and Argentina. We arranged the data from previous projects in a hierarchical system and conducted a study to identify the critical taxonomical levels that had the highest discriminative potential between sites (Europe and Argentina) or management types (forests, grasslands, fallows, succession, recultivation and agricultural sites).
• 3 For the Gamasina community, geographical location was by far more important than the influence of any land use type. The analysis including only the European sites demonstrated that communities belonging to sites subjected to different land uses were also significantly different.
• 4 The species data set provided a clearer separation of sites according to both the geographical and the land‐use gradients than the genus and family data sets. The genus and, to a lesser extent, the family approach may be sufficient to elucidate the influence of great geographical differences and also of certain land uses (e.g. grasslands from the forests and arable sites).
• 5 Species presence/absence data provided valuable information in our analyses, although the use of quantitative data yielded a clearer separation of sites.

     

NmDef02, a novel antimicrobial gene isolated from Nicotiana megalosiphon confers high‐level pathogen resistance under greenhouse and field conditions

Plant defensins are small cysteine‐rich peptides that inhibit the growth of a broad range of microbes. In this article, we describe NmDef02, a novel cDNA encoding a putative defensin isolated from Nicotiana megalosiphon upon inoculation with the tobacco blue mould pathogen Peronospora hyoscyami f.sp. tabacina. NmDef02 was heterologously expressed in the yeast Pichia pastoris, and the purified recombinant protein was found to display antimicrobial activity in vitro against important plant pathogens. Constitutive expression of NmDef02 gene in transgenic tobacco and potato plants enhanced resistance against various plant microbial pathogens, including the oomycete Phytophthora infestans, causal agent of the economically important potato late blight disease, under greenhouse and field conditions.     

Oocyte spindle proteomics analysis leading to rescue of chromosome congression defects in cloned embryos

Embryos produced by somatic cell nuclear transfer (SCNT) display low term developmental potential. This is associated with deficiencies in spindle composition prior to activation and at early mitotic divisions, including failure to assemble certain proteins on the spindle. The protein-deficient spindles are accompanied by chromosome congression defects prior to activation and during the first mitotic divisions of the embryo. The molecular basis for these deficiencies and how they might be avoided are unknown. Proteomic analyses of spindles isolated from normal metaphase II (MII) stage oocytes and SCNT constructs, along with a systematic immunofluorescent survey of known spindle-associated proteins were undertaken. This was the first proteomics study of mammalian oocyte spindles. The study revealed four proteins as being deficient in spindles of SCNT embryos in addition to those previously identified; these were clathrin heavy chain (CLTC), aurora B kinase, dynactin 4, and casein kinase 1 alpha. Due to substantial reduction in CLTC abundance after spindle removal, we undertook functional studies to explore the importance of CLTC in oocyte spindle function and in chromosome congression defects of cloned embryos. Using siRNA knockdown, we demonstrated an essential role for CLTC in chromosome congression during oocyte maturation. We also demonstrated rescue of chromosome congression defects in SCNT embryos at the first mitosis using CLTC mRNA injection. These studies are the first to employ proteomics analyses coupled to functional interventions to rescue a specific molecular defect in cloned embryos.     

Gene flow and the genealogical history of <Emphasis Type="Italic">Heliconius heurippa</Emphasis>

Background  

The neotropical butterfly Heliconius heurippa has a hybrid colour pattern, which also contributes to reproductive isolation, making it a likely example of hybrid speciation. Here we used phylogenetic and coalescent-based analyses of multilocus sequence data to investigate the origin of H. heurippa.     

Two sisters in the same dress: <Emphasis Type="Italic">Heliconius</Emphasis> cryptic species

Background  

Sister species divergence and reproductive isolation commonly results from ecological adaptation. In mimetic Heliconius butterflies, shifts in colour pattern contribute to pre- and post-mating reproductive isolation and are commonly correlated with speciation. Closely related mimetic species are therefore not expected, as they should lack several important sources of reproductive isolation.     

Mechanism and tissue specificity of nicotine-mediated lung S-adenosylmethionine reduction

We previously reported that chronic nicotine infusion blocks development of Pneumocystis pneumonia. This discovery developed from our work demonstrating the inability of this fungal pathogen to synthesize the critical metabolic intermediate S-adenosylmethionine and work by others showing nicotine to cause lung-specific reduction of S-adenosylmethionine in guinea pigs. We had found nicotine infusion to cause increased lung ornithine decarboxylase activity (rate-controlling enzyme of polyamine synthesis) and hypothesized that S-adenosylmethionine reduction is driven by up-regulated polyamine biosynthesis. Here we report a critical test of our hypothesis; inhibition of ornithine decarboxylase blocks the effect of nicotine on lung S-adenosylmethionine. Further support is provided by metabolite analyses showing nicotine to cause a strong diversion of S-adenosylmethionine toward polyamine synthesis and away from methylation reactions; these shifts are reversed by inhibition of ornithine decarboxylase. Because the nicotine effect on Pneumocystis is so striking, we considered the possibility of tissue specificity. Using laser capture microdissection, we collected samples of lung alveolar regions (site of infection) and respiratory epithelium for controls. We found nicotine to cause increased ornithine decarboxylase protein in alveolar regions but not airway epithelium; we conclude that tissue specificity likely contributes to the effect of nicotine on Pneumocystis pneumonia. Earlier we reported that the full effect of nicotine requires 3 weeks of treatment, and here we show recovery is symmetrical, also requiring 3 weeks after treatment cessation. Because this time frame is similar to pneumocyte turnover time, the shift in polyamine metabolism may occur as new pneumocytes are produced.