Evaluation of chemicals requiring metabolic activation in the EpiDerm™ 3D human reconstructed skin micronucleus (RSMN) assay.

The in vitro human reconstructed skin micronucleus (RSMN) assay in EpiDerm™ is a promising new assay for evaluating genotoxicity of dermally applied chemicals. A global pre-validation project sponsored by the European Cosmetics Association (Cosmetics Europe - formerly known as COLIPA), and the European Center for Validation of Alternative Methods (ECVAM), is underway. Results to date demonstrate international inter-laboratory and inter-experimental reproducibility of the assay for chemicals that do not require metabolism [Aardema et al.

The reconstructed skin micronucleus assay (RSMN) in EpiDerm™: detailed protocol and harmonized scoring atlas.

The European Cosmetic Toiletry and Perfumery Association (COLIPA), along with contributions from the European Centre for the Validation of Alternative Methods (ECVAM), initiated a multi-lab international prevalidation project on the reconstructed skin micronucleus (RSMN) assay in EpiDerm™ for the assessment of the genotoxicity of dermally applied chemicals. The first step of this project was to standardize the protocol and transfer it to laboratories that had not performed the assay before. Here we describe in detail the protocol for the RSMN assay in EpiDerm™ and the harmonized guidelines for scoring, with an atlas of cell images.

International prevalidation studies of the EpiDerm 3D human reconstructed skin micronucleus (RSMN) assay: transferability and reproducibility.

Recently, a novel in vitro reconstructed skin micronucleus (RSMN) assay incorporating the EpiDerm 3D human skin model (Curren et al., Mutat. Res.

Further development of the EpiDerm 3D reconstructed human skin micronucleus (RSMN) assay.

The upcoming ban on testing of cosmetics in animals by the European Union's 7th Amendment to the Cosmetics Directive will require genotoxicity safety assessments of cosmetics ingredients and final formulations to be based primarily on in vitro genotoxicity tests. The current in vitro test battery produces an unacceptably high rate of false positives, and used by itself would effectively prevent the use and development of many ingredients that are actually safe for human use. To address the need for an in vitro test that is more predictive of genotoxicity in vivo, we have developed an in vitro micronucleus assay using a three-dimensional human reconstructed skin model (EpiDerm) that more closely mimics the normal dermal exposure route of chemicals.

Apicoplast translation, transcription and genome replication: targets for antimalarial antibiotics.

Several antibiotics possess antimalarial properties, although the mechanisms by which they kill malaria parasites have been poorly understood. Recent data suggest that the target for multiple antimalarial antibiotics is the apicoplast, a chloroplast-like organelle of uncertain function. Translation inhibitors (such as tetracyclines, clindamycin and macrolides) and gyrase inhibitors (such as ciprofloxacin) cause modest antimalarial effects initially but are much more potent against the progeny of treated parasites.

Contributions of different mosquito species to the transmission of lymphatic filariasis in central Nigeria: implications for monitoring infection by PCR in mosquito pools.

Background: Members of the Anopheles gambiae complex are important vectors of lymphatic filariasis (LF) in sub-Saharan Africa, but little is known about the relative contributions of all mosquitoes to lymphatic filariasis transmission in this area.

Methods: Over a 28 month period, mosquitoes were collected from 13 villages in Plateau and Nasarawa states in central Nigeria and dissected to determine W. bancrofti infection status.

Multiple antibiotics exert delayed effects against the Plasmodium falciparum apicoplast.

Several classes of antibiotics exert antimalarial activity. The mechanisms of action of antibiotics against malaria parasites have been unclear, and prior studies have led to conflicting results, in part because they studied antibiotics at suprapharmacological concentrations. We examined the antimalarial effects of azithromycin, ciprofloxacin, clindamycin, doxycycline, and rifampin against chloroquine-resistant (W2) and chloroquine-sensitive (3D7) Plasmodium falciparum strains.

Tetracyclines specifically target the apicoplast of the malaria parasite Plasmodium falciparum.

Tetracyclines are effective but slow-acting antimalarial drugs whose mechanism of action remains uncertain. To characterize the antimalarial mechanism of tetracyclines, we evaluated their stage-specific activities, impacts on parasite transcription, and effects on two predicted organelle targets, the apicoplast and the mitochondrion, in cultured Plasmodium falciparum. Antimalarial effects were much greater after two 48-h life cycles than after one cycle, even if the drugs were removed at the end of the first cycle.

Globalization and the population structure of Toxoplasma gondii.

Toxoplasma gondii is a protozoan parasite that infects nearly all mammal and bird species worldwide. Usually asymptomatic, toxoplasmosis can be severe and even fatal to many hosts, including people. Elucidating the contribution of genetic variation among parasites to patterns of disease transmission and manifestations has been the goal of many studies.

Genetic contribution to variation in larval development time, adult size, and longevity of starved adults of Anopheles gambiae.

The variation in mosquito life-history traits such as adult size has been studied with respect to environmental factors, but the genetic contribution to such variation has received almost no consideration. Using a full-sib design of F1s produced by wild caught Anopheles gambiae (M molecular form) females, we estimated broad-sense heritability of larval developmental time, adult size (based on dry weight and wing length), and longevity of starved adults. These traits were correlated (at the phenotypic level) with each other in females and males (|r(p)|>0.

Biosynthesis, localization, and processing of falcipain cysteine proteases of Plasmodium falciparum.

Falcipain-2 and -3 are cysteine proteases of erythrocytic Plasmodium falciparum parasites that appear to function principally as hemoglobinases. To better understand their biological roles, we analyzed the biosynthesis, localization, and processing of these enzymes in cultured parasites. Immunoprecipitation of metabolically labeled proteins indicated that falcipain-2 was synthesized through the trophozoite stage, falcipain-3 appeared in late trophozoites/early schizonts, and both proteases persisted for at least 6 h after synthesis.

Variation in the structure of Toxoplasma gondii and the roles of selfing, drift, and epistatic selection in maintaining linkage disequilibria.

Previous studies of Toxoplasma gondii, based on samples dominated by clinical isolates, have concluded that its population structure is clonal, despite the sexual reproduction that occurs in cats. To determine whether this applies to non-clinical isolates, we compared patterns of linkage disequilibrium (LD) among seven loci in samples of T. gondii from Brazil and the US.

Transmission dynamics of Toxoplasma gondii on a pig farm.

Transmission of Toxoplasma gondii infection on a pig farm in New England was investigated using genetic and ecological methods to (i) determine if infection of pigs was a result of a single source, such as in an epizootic situation (e.g. outbreak) or of multiple sources, such as in an enzootic situation, (ii) identify the main source species of infection to pigs and (iii) evaluate the role of the environment surrounding the farm as the source of infection on the farm.

Differential induction of mafF, mafG and mafK expression by electrophile-response-element activators.

The three small Maf proteins, MafF, MafG and MafK, have been implicated in a number of physiological processes, including development, differentiation, haematopoiesis and stress response. Here we report the constitutive expression of mafF, mafG and mafK in six human cell lines derived from various tissues (HepG2, IMR-32, K-562, HEK-293, RD and A549). The expression patterns of mafF, mafG and mafK varied widely among cell lines.