Concentré de globules rouges | EPFL Graph Search

Les concentrés de globules rouges, également appelés concentrés cellulaires, ou encore culot globulaire, sont des globules rouges qui ont été séparés en vue d'une transfusion sanguine . Utilisations médicales Les concentrés cellulaires sont généralement utilisés en cas d'anémie qui provoque des symptômes ou lorsque le taux d'hémoglobine est inférieur à 70 à 80 g/L (7 à 8 g/dL). Chez l'adulte, une unité augmente le taux d'hémoglobine d'environ 10 g/L (1 g/dL). Des transfusions répétées peuvent être nécessaires chez les personnes recevant une chimiothérapie anticancéreuse ou qui ont des troubles de l'hémoglobine . L'appariement croisé est généralement requis avant que le sang ne soit donné, Il est administré par injection dans une veine . Effets secondaires Les effets secondaires comprennent des réactions allergiques telles que l'anaphylaxie, la dégradation des globules rouges, l'infection, la surch

Proteins interacting with PfEMP1 in P. falciparum infected erythrocyte

Damien Jacot

During infection in humans, P. falciparum invades and refurbishes the red blood cells (RBCs) in order to persist and proliferate. Parasite survival depends on expression of a parasite encoded cytoadherence ligand at the surface of the infected RBC called PfEMP1 (P. falciparum erythrocyte membrane protein 1). PfEMP1 comprises a N-terminal extracellular part, which mediates binding to receptors at the host endothelium. It also contains a C-terminal part which is conserved among all PfEMP1 molecules. This acidic terminal segment (ATS) anchors PfEMP1 to the membrane of infected RBCs and has a role for trafficking. To bring proteins to the RBC surface, P. falciparum builds its own trafficking machinery de novo since the erythrocytes do not contain secretory organelles. These new structures include parasite derived compartments called Maurer's clefts (MCs) located at the RBC periphery. The resident MCs protein MAHRP1 (membrane-associated histidine-rich protein 1) has been shown to be critical for PfEMP1 trafficking. A MAHRP1 KO strain had no PfEMP1 on the RBC surface but accumulated PfEMP1 within the parasite. MAHRP1 is a 28.9kDa protein with 249 amino acids containing a N-terminal, a transmembrane, and a C-terminal domain comprising histidine-rich repeats. To re-establish PfEMP1 trafficking, the MAHRP1 KO parasite line was complemented with various truncated HA-tagged fragments of MAHRP1. Immunofluorescent assays (IFAs) showed that the Cterminal domain with the histidine-rich repeats was not essential for PfEMP1 trafficking.

{MAHRP1}_{1-130}

and

{MAHRP1}_{1-169}

were exported to MCs and restored trafficking of PfEMP1. Shorter MAHRP1 fragments were not exported to MCs and PfEMP1 transport remained impaired. New transfection constructs were designed including the C-terminal part to identify important domain(s) of MAHRP1 for PfEMP1 trafficking. To identify other proteins interacting with PfEMP1, the ATS domain of PfEMP1 was recombinantly expressed and used in pull-down experiments. In these experiments using parasite lysates, PF14_0377 was identified as a potential interaction partner. This protein has been described as putative, vesicular-associated membrane protein. To subsequently assess the interaction(s) and the localization(s), PF14_0377 was cloned and transfected in 3D7 for IFAs. Due to time restrictions all these new transfectants could not be analyzed completely

2009

Active Nanorheology with Plasmonics

Peer Fischer, Hyeonho Jeong, Tian Qiu

Nanoplasmonic systems are valued for their strong optical response and their small size. Most plasmonic sensors and systems to date have been rigid and passive. However, rendering these structures dynamic opens new possibilities for applications. Here we demonstrate that dynamic plasmonic nanoparticles can be used as mechanical sensors to selectively probe the rheological properties of a fluid in situ at the nanoscale and in microscopic volumes. We fabricate chiral magneto-plasmonic nanocolloids that can be actuated by an external magnetic field, which in turn allows for the direct and fast modulation of their distinct optical response. The method is robust and allows nanorheological measurements with a mechanical sensitivity of similar to 0.1 cP, even in strongly absorbing fluids with an optical density of up to OD similar to 3 (similar to 0.1% light transmittance) and in the presence of scatterers (e.g., 50% v/v red blood cells).

Amer Chemical Soc2016

Plasmodium falciparum NIMA-related kinase Pfnek-1: sex specificity and assessment of essentiality for the erythrocytic asexual cycle

The Plasmodium falciparum kinome includes a family of four protein kinases (Pfnek-1 to -4) related to the NIMA (never-in-mitosis) family, members of which play important roles in mitosis and meiosis in eukaryotic cells. Only one of these, Pfnek-1, which we previously characterized at the biochemical level, is expressed in asexual parasites. The other three (Pfnek-2, -3 and -4) are expressed predominantly in gametocytes, and a role for nek-2 and nek-4 in meiosis has been documented. Here we show by reverse genetics that Pfnek-1 is required for completion of the asexual cycle in red blood cells and that its expression in gametocytes in detectable by immunofluorescence in male (but not in female) gametocytes, in contrast with Pfnek-2 and Pfnek-4. This indicates that the function of Pfnek-1 is non-redundant with those of the other members of the Pfnek family and identifies Pfnek-1 as a potential target for antimalarial chemotherapy. A medium-throughput screen of a small-molecule library provides proof of concept that recombinant Pfnek-1 can be used as a target in drug discovery.

2011

Proteins interacting with PfEMP1 in P. falciparum infected erythrocyte

Damien Jacot

{MAHRP1}_{1-130}

and

{MAHRP1}_{1-169}

2009