Methodological framework for assessing malaria risk associated with climate change in Côte d'Ivoire.

Malaria is the leading cause of morbidity among children under five years of age and pregnant women in Côte d'Ivoire. We assessed the geographical distribution of its risk in all climatic zones of the country based on the Fifth Assessment Report (AR5) of the United Nations Intergovernmental Panel on Climate Change (IPCC) approach to climate risk analysis. This methodology considers three main driving components affecting the risk: Hazard, exposure and vulnerability.

Microdissection and cloning of DNA from landmark loops of amphibian lampbrush chromosomes.

Microdissection of the "globular" and "granular" landmark loops of Pleurodeles lampbrush chromosomes and subsequent cloning of their DNA yielded several recombinant clones. The 6.6-kb insert of one of them was subcloned and the 600 bp of one subclone was characterized by Southern and slot hybridizations as well as by sequencing.

Effects of cold shock treatment on lampbrush chromosomes of amphibian oocytes.

When females of the newt Pleurodeles waltl, normally raised in our laboratory at 20 degrees C, were placed in 8 degrees C water for several days, striking modifications occurred in the structure of oocyte lampbrush chromosomes: numerous normal-type lateral loops were partially reduced in size and number, while hyperdeveloped loops of a new morphological type occurred at constant, reproducible loci. However, induction of these cold loops apparently was not accompanied by preferential RNA synthesis at their levels. Cold loops resulted from the decompaction of specific landmarks, the granular loops.

Chromosomes of amphibian oocytes as a model for gene expression: significance of lampbrush loops.

Amphibian lampbrush chromosome loops exhibit morphological variability in their RNP matrix. The biological significance of such variability remains unknown. In order to approach this problem, the structural organization of each RNP matrix type was analyzed in relation to transcriptional and post-transcriptional processes.

Effects of cold shock treatment on amphibian oocytes: alteration of heterogenous nuclear RNP morphology.

In cold-stressed oocytes of Pleurodeles waltl, lampbrush chromosome lateral loops exhibited important structural modifications which were visualized under light microscopy. Electron microscopy study revealed that the RNP particles associated with growing transcripts in the matrix of these loops were 15 nm at 8 degrees C compared to 30 nm at normal temperature (20 degrees C); hnRNP isolated from cold-stressed oocytes sedimented at 15 S in sucrose, while those from control oocytes sedimented at 30 S, as expected. However, under both normal and cold stress conditions, hnRNP possessed a buoyant density of 1.

Cold-induced changes in amphibian oocytes.

Female Pleurodeles waltl newts (Amphibia, urodele), usually raised at 20 degrees C, were submitted to low temperatures; oocytes responded to this cold stress by drastic changes both in lampbrush chromosome structure and in protein pattern. Preexisting lateral loops of lampbrush chromosomes were reduced in size and number, while cold-induced loops which were tremendously developed, occurred on defined bivalents of the oocyte at constant, reproducible sites. A comparison of protein patterns in control and stressed oocytes showed two main differences: in stressed oocytes, overall protein synthesis was reduced, except for a set of polypeptides, the "cold-stress proteins"; second, there was a striking inversion of the relative amount of beta- and gamma-actin found in the oocyte nucleus before and after cold stress.

Structure of landmark loop ribonucleoprotein matrices in Pleurodeles waltlii lampbrush chromosomes visualized by scanning electron microscopy.

Landmark loop ribonucleoprotein (RNP) matrices of Pleurodeles waltlii lampbrush chromosomes were systematically examined by scanning electron microscopy (SEM). The results, which corroborated similar studies by electron microscopy (EM), showed that RNP transcripts in normal loops, and RNP matrices in granular, globular and dense loops, are composed of one basic structure: an RNP particle with a diameter of 30 nm. SEM observations also clarified the spatial arrangement of this particle in the RNP matrices of all the loop types examined.

Size uniformity of ribonucleoprotein matrix particles in loops of Pleurodeles waltlii lampbrush chromosomes visualized by electron microscopy.

The different kinds of loops of lampbrush chromosomes were identified in phase contrast, then analysed by electron microscopy on thin sections. Examination at high magnification showed that the basic structure of the ribonucleoprotein (RNP) matrix of all kinds of loops is a 30 nm RNP particle. Furthermore, this study suggests that the morphological differences between the loops are due to the extent of aggregation of these particles.

Evidence for a particular mode of transcription in globular loops of lampbrush chromosomes of the newt Pleurodeles waltlii.

In amphibian lampbrush chromosomes, many loops have a specific morphology; this is the case for globular loops in the newt Pleurodeles. We have previously shown that the specific morphology of these loops is linked to an extreme compactness of the transcription products which make up their matrix. We investigated RNA synthesis in this type of loop by carrying out autoradiographic and transcription inhibition studies.