Haemosporidian Parasites of Antelopes and Other Vertebrates from Gabon,Central Africa

Re-examination, using molecular tools, of the diversity of haemosporidian parasites (among which the agents of human malaria are the best known) has generally led to rearrangements of traditional classifications. In this study, we explored the diversity of haemosporidian parasites infecting vertebrate species (particularly mammals, birds and reptiles) living in the forests of Gabon (Central Africa), by analyzing a collection of 492 bushmeat samples. We found that samples from five mammalian species (four duiker and one pangolin species), one bird and one turtle species were infected by haemosporidian parasites. In duikers (from which most of the infected specimens were obtained), we demonstrated the existence of at least two distinct parasite lineages related to Polychromophilus species (i.e., bat haemosporidian parasites) and to sauropsid Plasmodium (from birds and lizards). Molecular screening of sylvatic mosquitoes captured during a longitudinal survey revealed the presence of these haemosporidian parasite lineages also in several Anopheles species, suggesting a potential role in their transmission. Our results show that, differently from what was previously thought, several independent clades of haemosporidian parasites (family Plasmodiidae) infect mammals and are transmitted by anopheline mosquitoes.     

Risk Factors and Screening for Trypanosoma cruzi Infection of Dutch Blood Donors

Background

Blood donors unaware of Trypanosoma cruzi infection may donate infectious blood. Risk factors and the presence of T. cruzi antibodies in at-risk Dutch blood donors were studied to assess whether specific blood safety measures are warranted in the Netherlands.

Methodology

Birth in a country endemic for Chagas disease (CEC), having a mother born in a CEC, or having resided for at least six continuous months in a CEC were considered risk factors for T. cruzi infection. From March through September 2013, risk factor questions were asked to all donors who volunteered to donate blood or blood components. Serum samples were collected from donors reporting one or more risk factors, and screened for IgG antibodies to T. cruzi by EIA.

Results

Risk factors for T. cruzi infection were reported by 1,426 of 227,278 donors (0.6%). Testing 1,333 at-risk donors, none (0.0%; 95%, CI 0.0–0.4%) was seroreactive for IgG antibodies to T. cruzi. A total of 472 donors were born in a CEC; 553 donors reported their mother being born in a CEC; and 1,121 donors reported a long-term stay in a CEC. The vast majority of reported risk factors were related to Suriname and Brazil. Overall, the participants resided for 7,694 years in CECs, which equals 2.8 million overnight stays. Of those, 1.9 million nights were spent in Suriname.

Conclusions/Significance

Asymptomatic T. cruzi infection appears to be extremely rare among Dutch blood donors. Blood safety interventions to mitigate the risk of T. cruzi transmission by transfusion would be highly cost-ineffective in the Netherlands, and are thus not required.     

Proteomic analysis of Rac1 signaling regulation by guanine nucleotide exchange factors

The small GTPase Rac1 is implicated in various cellular processes that are essential for normal cell function. Deregulation of Rac1 signaling has also been linked to a number of diseases, including cancer. The diversity of Rac1 functioning in cells is mainly attributed to its ability to bind to a multitude of downstream effectors following activation by Guanine nucleotide Exchange Factors (GEFs). Despite the identification of a large number of Rac1 binding partners, factors influencing downstream specificity are poorly defined, thus hindering the detailed understanding of both Rac1's normal and pathological functions. In a recent study, we demonstrated a role for 2 Rac-specific GEFs, Tiam1 and P-Rex1, in mediating Rac1 anti- versus pro-migratory effects, respectively. Importantly, via conducting a quantitative proteomic screen, we identified distinct changes in the Rac1 interactome following activation by either GEF, indicating that these opposing effects are mediated through GEF modulation of the Rac1 interactome. Here, we present the full list of identified Rac1 interactors together with functional annotation of the differentially regulated Rac1 binding partners. In light of this data, we also provide additional insights into known and novel signaling cascades that might account for the GEF-mediated Rac1-driven cellular effects.     

A global review and meta-analysis of applications of the freshwater Fish Invasiveness Screening Kit

Reviews in Fish Biology and Fisheries - The freshwater Fish Invasiveness Screening Kit (FISK) has been applied in 35 risk assessment areas in 45 countries across the six inhabited continents (11...     

Fluorescence in blue light (FLU) is involved in inactivation and localization of glutamyl‐tRNA reductase during light exposure

Fluorescent in blue light (FLU) is a negative regulator involved in dark repression of 5‐aminolevulinic acid (ALA) synthesis and interacts with glutamyl‐tRNA reductase (GluTR), the rate‐limiting enzyme of tetrapyrrole biosynthesis. In this study, we investigated FLU‘s regulatory function in light‐exposed FLU‐overexpressing (FLUOE) Arabidopsis lines and under fluctuating light intensities in wild‐type (WT) and flu seedlings. FLUOE lines suppress ALA synthesis in the light, resulting in reduced chlorophyll content, but more strongly in low and high light than in medium growth light. This situation indicates that FLU's impact on chlorophyll biosynthesis depends on light intensity. FLU overexpressors contain strongly increased amounts of mainly membrane‐associated GluTR. These findings correlate with FLU‐dependent localization of GluTR to plastidic membranes and concomitant inhibition, such that only the soluble GluTR fraction is active. The overaccumulation of membrane‐associated GluTR indicates that FLU binding enhances GluTR stability. Interestingly, under fluctuating light, the leaves of flu mutants contain less chlorophyll compared with WT and become necrotic. We propose that FLU is basically required for fine‐tuned ALA synthesis. FLU not only mediates dark repression of ALA synthesis, but functions also to control balanced ALA synthesis under variable light intensities to ensure the adequate supply of chlorophyll.