A microfluidic paper analytical device using capture aptamers for the detection of PfLDH in blood matrices.

Background: The prevalence and death rate arising from malaria infection, and emergence of other diseases showing similar symptoms to malaria require the development of malaria-specific and sensitive devices for its diagnosis. To address this, the design and fabrication of low-cost, rapid, paper-based analytical devices (µPAD) using surface-immobilized aptamers to detect the presence of a recombinant malarial biomarker-Plasmodium falciparum lactate dehydrogenase (rPfLDH)-is reported in this study.

Methods: Test zones on paper surfaces were created by covalently immobilizing streptavidin to the paper, subsequently attaching biotinylated aptamers to streptavidin.

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.

A Plasmodium falciparum transcriptional cyclin-dependent kinase-related kinase with a crucial role in parasite proliferation associates with histone deacetylase activity.

Cyclin-dependent protein kinases (CDKs) are key regulators of the eukaryotic cell cycle and of the eukaryotic transcription machinery. Here we report the characterization of Pfcrk-3 (Plasmodium falciparum CDK-related kinase 3; PlasmoDB identifier PFD0740w), an unusually large CDK-related protein whose kinase domain displays maximal homology to those CDKs which, in other eukaryotes, are involved in the control of transcription. The closest enzyme in Saccharomyces cerevisiae is BUR1 (bypass upstream activating sequence requirement 1), known to control gene expression through interaction with chromatin modification enzymes.

Critical sensitivity effect in an interferometer sensor.

We report the observation of anomalous behavior in the spectral sensitivity response in a specially designed waveguided interferometer sensor. Approaching a definite critical point, the sensitivity increases nonlinearly. Furthermore, at the critical wavelength a new effect of splitting or bifurcation of a minimum dip is observed.

An essential role for the Plasmodium Nek-2 Nima-related protein kinase in the sexual development of malaria parasites.

The molecular control of cell division and development in malaria parasites is far from understood. We previously showed that a Plasmodium gametocyte-specific NIMA-related protein kinase, nek-4, is required for completion of meiosis in the ookinete, the motile form that develops from the zygote in the mosquito vector. Here, we show that another NIMA-related kinase, Pfnek-2, is also predominantly expressed in gametocytes, and that Pfnek-2 is an active enzyme displaying an in vitro substrate preference distinct from that of Pfnek-4.