Polymorphism of intron-1 in the voltage-gated sodium channel gene of Anopheles gambiae s.s. populations from Cameroon with emphasis on insecticide knockdown resistance mutations

Sequence variation at the intron-1 of the voltage-gated sodium channel gene in Anopheles gambiae M- and S-forms from Cameroon was assessed to explore the number of mutational events originating knockdown resistance ( kdr ) alleles. Mosquitoes were sampled between December 2005 and June 2006 from three geographical areas: (i) Magba in the western region; (ii) Loum, Tiko, Douala, Kribi, and Campo along the Atlantic coast; and (iii) Bertoua, in the eastern continental plateau. Both 1014S and 1014F kdr alleles were found in the S-form with overall frequencies of 14% and 42% respectively. Only the 1014F allele was found in the M-form at lower frequency (11%). Analysis of a 455 bp region of intron-1 upstream the kdr locus revealed four independent mutation events originating kdr alleles, here named MS1 -1014F, S1-1014S and S2-1014S kdr- intron-1 haplotypes in S-form and MS3-1014F kdr- intron-1 haplotype in the M-form. Furthermore, there was evidence for mutual introgression of kdr 1014F allele between the two molecular forms, MS1 and MS3 being widely shared by them. Although no M/S hybrid was observed in analysed samples, this wide distribution of haplotypes MS1 and MS3 suggests inter-form hybridizing at significant level and emphasizes the rapid diffusion of the kdr alleles in Africa. The mosaic of genetic events found in Cameroon is representative of the situation in the West–Central African region and highlights the importance of evaluating the spatial and temporal evolution of kdr alleles for a better management of insecticide resistance.     

Detection and Immunolocalization of Human Erythrocyte Spectrin Immunoanalogues in Toxoplasma gondii (Protozoan, Parasite)

ABSTRACT. We demonstrated here the presence of proteins antigenically related to human erythroid spectrin in the parasitic protozoan Toxoplasma gondii . A high molecular weight doublet (M, 245-240,000), present in equimolar ratio, and low molecular weight polypeptides (M, 75,000) were reacted with monoclonal and polyclonal anti-human erythroid spectrin antibodies on electroblotted nitrocellulose sheets. Indirect immunofluorescence assay clearly showed that these proteins were localized in the anterior pole of the organism. Immunogold staining further revealed specific labeling of conoid, rhoptries, micronemes, and dense granules of the apical complex. The presence of the M, 245–240,000 doublet and the M, 75,000 spectrin-like proteins in the anterior pole of T. gondii may probably be consistent with a structural stabilizer function in its organciles which are suspected to be involved in the process of host cell invasion.     

The monophyly of the subfamily Perisphaeriinae (Dictyoptera: Blattaria: Blaberidae)

A new definition of the subfamily Perisphaeriinae is given on the basis of five synapomorphies described from male and female genitalia and head morphology. The subfamily comprises eighteen genera: Bantua , Compsagis , Cyrtotria , Derocalymma , Ellipsica , Elliptoblatta , Gymnonyx , Hostilia , Laxta , Neolaxta , Perisphaeria , Perisphaerus , Pilema , Platysilpha , Poeciloblatta , Pseudoglomeris , Trichoblatta , Zuluia . Two genera are newly assigned to the Perisphaeriinae: Laxta and Neolaxta . Four genera are removed from the Perisphaeriinae: Aptera , Blepharodera , Eustegasta , Isoniscus . One new generic synonymy is proposed: Pronaonota as a synonym of Pilema . The subfamily has a large geographical range including tropical Africa, the Arabian Peninsula, Asia and Australia.     

New occurrences of the wood Protocupressinoxylon purbeckensis Francis: implications for terrestrial biomes in southwestern Europe at the Jurassic/Cretaceous boundary

Abstract:  Previously known from the Kimmeridgian–Portlandian of Dorset (UK) only, Protocupressinoxylon purbeckensis wood is reported here from the Kimmeridgian of Asturias (Spain) and Ajoie (Switzerland). The morphospecies taxonomy and nomenclature are discussed, and new supplementary illustrations are given. The P. purbeckensis tree was growing in dry strongly seasonal (tropophilous) environments, and the new occurrences suggest that such a climate prevailed on land all over southwestern Europe at the end of the Jurassic (Kimmeridgian sensu anglico – Portlandian). The review of fossil wood data indicates that such a stressful environment may have constrained terrestrial biocoenoses and their evolution at the Jurassic/Cretaceous boundary. But wood generic diversity curves are also strikingly similar to that drawn 20 years ago for nonmarine tetrapods, implying a fossil Lagerstätte effect.     

TAXONOMIC REEVALUATION OF GEMMULOBORSONIA SHUTO, 1989 (GASTROPODA: CONOIDEA), WITH A DESCRIPTION OF NEW RECENT DEEP-WATER SPECIES

The genus Gemmulobonorua Shuto, 1989, until now known only fromUpper Miocene-Lower Pleistocene deposits of the Tethys, is recordedin Recent faunas, with five new bathyal species from New Caledonia,Indonesia, Mozambique Channel, and the Philippines. Radularmorphology indicates that Gemmuloborsorua belongs to the subfamilyTurnnae, and not to Borsoruinae, where it had been allocatedbased on shell morphology. Columellar pleats, which have longbeen considered a synapomorphy of the borsornid group of genera,have thus been acquired independently in the Turnnae. The consequenceof this finding is that the current (sub)fanuly allocation ofsome genera, based on shell characters only, may need reevaluation. (Received 21 July 1995; accepted 8 August 1995)     

Climate change impacts on structure and diversity of fish communities in rivers

It is widely accepted that climate change constrains biota. Yet, because of the lack of consistent multisite and multitaxon surveys, few studies have addressed general rules about how climate change impacts on structure and diversity of animal communities. Especially, the relative influence of nonclimatic anthropogenic disturbances on this impact is fairly unknown. Here, we present for the first time a meta-analysis assessing the effect of global warming on stream organisms. Fish communities of large rivers in France undergoing various anthropogenic pressures showed significant increase in proportions of warm-water species and of specific richness during the last 15–25 years. Conversely, the equitability decreased, indicating a gradual decrease of the number of dominant species. Finally, the total abundance increased, coupled with rejuvenation and changes in size-structure of the communities. Interestingly, most of these effects were not depressed by the strength of nonclimatic anthropogenic disturbances. Conversely, geographical location of communities and especially closeness of natural barriers to migration could influence their response to climate change. Indeed, increase in the proportion of southern species seemed hindered at sites located close to the southern limit of the European species' geographical ranges. This work provides new evidence that climate change have deep impacts on communities which, by overtaking the effects of nonclimatic anthropogenic disturbances, could be more substantial than previously thought. Overall, our results stress the importance of considering climate change impacts in studies addressing community dynamics, even in disturbed sites.     

Radiation précoce des coniferes Taxodiaceae et bois affines du Jurassique de France

Three Jurassic fossil-wood taxa from France have been investigated, Taxodioxylon lemoignei n.sp. from the Oxfordian, Prototaxodioxylon romanensis Philippe from the Pliensbachian, and P. sp. from the Hettangian. Wood of this type, prior to the Late Cretaceous, is reviewed. The Oxfordian wood shows a structure characteristic of a Taxodiaceae, previously unknown before the Late Cretaceous. It is well differentiated from contemporaneous woods of Cupressaceae. The systematic position of the Liassic forms, with mixed type of pitting, remains more arguable. These taxodiaceous woods, along with known reproductive structures, reinforce the idea that this family was well separated from Cupressaceae already in the Middle Jurassic. *** Fossil wood, Jurassic, France, Taxodiaceae.