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The whitemouth croaker ( Micropogonias furnieri ) is the main fish species of the demersal fisheries along the Atlantic coast of South America. There has been much debate regarding the number of stocks of this heavily exploited fish off the Brazilian coast between latitudes 23° S and 33° S. Analyses of morphometric and meristic data suggest that two stocks exist in that area, but this conclusion was not supported by genetic studies. Here, we used polymorphic nuclear loci (microsatellite and intron size polymorphisms) to compare samples of M. furnieri collected between Rio de Janeiro (23°02′ S) and Chui (33°41′ S), as well as samples from much further north, along the coast of Braganca at Para State (1°03′ S). Our data demonstrate the existence of three distinct stocks of the species in Brazil: one in North Brazil (Braganca – Para State), as previously suggested; and two previously not detected genetically: one between 23° S and 29° S; and another south of parallel 29° S. These findings indicate that the fisheries of the three areas should be managed as distinct stocks.

This study measured the relative expression of the genes coding for Na+, K+-ATPase 1α(NAKA), voltage-dependent anion channel (VDAC), cytochrome c oxidase-1 (COX), and NADH dehydrogenase (NDH), in gills of six wild populations of a West African tilapia species, acclimatised to a range of seasonal (rainy or dry) salinities in coastal, estuarine and freshwater sites. Previous laboratory experiments have demonstrated that these genes, involved in active ion transport, oxidative phosphorylation, and intra-cellular ATP transport, are relatively over-expressed in gill tissues of this species acclimated to high salinity. Positive correlations between relative expression and ambient salinity were found for all genes in the wild populations (Spearman rank correlation, p

We characterised four samples of gilthead sea bream from the two western Mediterranean banks with three microsatellite loci and two RAPDs systems. Contrarily to what could be predicted for a highly mobile species with a planktonic larval dispersal phase, we observed a strong and significant genetic differentiation at all loci between the two banks (F(st)=0.069(***)), whereas two samples from the Gulf of Lions were almost identical (F(st)=0.003 ns) while the two from the Gulf of Annaba displayed varied levels of differentiation according to the molecular marker considered. RAPDs showed a similar trend as microsatellites. The reasons for this surprisingly strong genetic differentiation, as compared to what has been observed in other species over comparable geographical distance, may be sought for either in a smaller as suspected larval dispersal, or in the non-neutrality of the loci studied.

International audience; A physical sublimation process, generally used for the metals, has been applied to an amino acid, glycine. When this molecule is submitted by this physical process, it could acquire new chemical and physical properties so new therapeutic activities. We have studied the differences of the two glycine forms in solid state and in aqueous solution using the physical and chemical analysis. This study has been carried out with the following techniques: differential scanning calorimeter (DSC), thermogravimetric analyses (TG), thermostimulated current (TSC) and electrochemical impedance.

Coastal and estuarine areas in the Bay of Biscay are essential nursery habitats for sole (Solea solea). Using three intronic markers, we investigated patterns of genetic differentiation among cohorts of juveniles (0+, 1+, sub-adults) inhabiting four major nurseries in the Vilaine and Loire river estuaries, the Pertuis d' Antioche strait, and the Gironde estuary. Genetic differentiation was not significant for the age 0- and 1-groups, but was among sub-adult samples (theta(WC) = 0.017; P = 0.031). Hierarchical analyses of genotypic frequencies by nested multivariate ANOVA using redundancy analysis indicated that northern nurseries of Loire and Vilaine rivers had different patterns of genotypic variation with age than southern nurseries of the Pertuis d' Antioche and Gironde estuaries (F = 1.36; P = 0.007). Bay of Biscay nurseries appeared to be spatially structured between a southern and a northern group that exhibit different genotypic distributions. Genetic drift and gene flow explains this pattern poorly, but a statistical test (P < 0.035) suggested that the metallothionein (MT) locus may be significantly impacted by selection in southern estuaries. As metallothionein is involved in heavy-metal detoxification, and southern nurseries are known to be affected by cadmium, this indicates a possible correlation between observed genotypic distributions and some nursery habitat features in sole. Some selective patterns might also be proposed to explain patterns of linkage disequilibrium observed at amylase loci in three of the four nurseries. (C) 2008 Elsevier Ltd. All rights reserved.

International audience; A multilocus analysis was initiated in order to infer the general effect of demography and the indirect effect of positive selection on some chromosome segments in Bathymodiolus. Mussels of the genus Bathymodiolus inhabit the very hostile, fragmented and variable environment of deep-sea hydrothermal vents which is thought to cause recurrent population bottlenecks via extinction/colonisation processes and adaptation to new environmental conditions. In the course of this work we discovered that the assumption of neutrality of non-coding polymorphisms usually made in genome scan experiments was likely to be violated at one of the loci we analysed. The direct effect of slight purifying selection on non-coding polymorphisms shares many resemblances with the indirect effect of positive selection through genetic hitchhiking. Combining polymorphism with divergence data for several closely related species allowed us to obtain different expectations for the direct effect of negative selection and the indirect effect of positive selection. We observed a strong excess of rare non-coding polymorphisms at the second intron of the EF1α gene in the two species Bathymodiolus azoricus and Bathymodiolus thermophilus, while two other loci, the mitochondrial COI gene and an intron of the Lysozyme gene, did not exhibit such a deviation. In addition, the divergence rate of the EF1α intron was estimated to be unexpectedly low when calibrated using the closure of the Panama Isthmus that interrupted gene flow between the two species. The polymorphism to divergence ratio was similar to the one observed for the other two loci, in accordance to the hypothesis of purifying selection. We conclude that slight purifying selection is likely to act on polymorphic intronic mutations of the EF1α second intron and discuss the possible relationship with the specific biology of Bathymodiolus mussels.

With its large 12-membered ring channel structure and the periodic arrangement of its e-cage, cancrinite can host molecular water and a variety of guest anions such as nitrate, carbonate, chloride, and hydroxide. A series of cancrinite samples containing varying amounts of nitrate, carbonate, and water were investigated using high temperature oxide melt drop solution calorimetry. The enthalpies of formation from constituent oxides and from elements at room temperature were obtained. The enthalpy of formation from oxides becomes less exothermic and the water content decreases with increasing salt inclusion (NaNO3 and Na2CO3). This indicates a destabilizing effect of salt hosting on the cancrinite structure. The negative correlation between the amounts of salt and water inclusion suggests competition between water molecules, guest anions and possibly Na cations for the occupancy of the cancrinite channel and cage sites.

Euryhaline teleosts possess the capacity to osmoregulate under various environmental conditions (freshwater to hypersaline water). This physiological capacity is generally monitored using enzyme activity assays (Na+/K+-ATPase...), hormones quantification (prolactine, growth hormone) or their mRNAs expression. To date, few studies addressed the genetic correlates of adaptation to varying salinity at a molecular level in such fish. In the sea bass Dicentrarchus labrax, genetic differentiation was observed at specific allozyme loci between lagoon- and open-sea populations. In the present study, we investigated transcriptomic response of D. labrax to salt- and freshwater acclimation in two organs involved in osmoregulation, gill and intestine. By using suppression subtractive hybridisation, we characterised 586 partial cDNA sequences encoding proteins potentially involved in the metabolism of sea bass acclimated to salt- or freshwater under experimental conditions. Using these results, we first characterised complete genomic sequence of a carbonic anhydrase and then analysed mRNA expression of genes potentially involved in osmoregulation mechanisms (Na+/K+-ATPase, carbonic anhydrase, angiotensin-converting enzyme and claudin-3), cell-cycle regulation (secretagogin) and immune system (nephrosin) in gill and intestine of wild fish from open sea and lagoons. Our analyses indicate a strong tissue- and environmental-dependant expression pattern for all the genes studied. A transcriptomic approach such as described in the present paper provides thus a first description of genes involved in metabolic or structural functions important for coping with environmental salinity variations in a euryhaline fish like the common sea bass D. labrax. It should be supplemented by proteomics to check the direct involvement of the gene products at the protein level, and by polymorphism analyses if one is to understand population or individual fluctuations in acclimation to salinity variation. (c) 2006 Elsevier B.V. All rights reserved.

Polymorphisms of nuclear DNA markers were used to study the genetic variation and differentiation among populations of Penaeus merguiensis in Thailand. The data consisted of three nuclear loci analysed for 163 individuals from five populations collected from the Gulf of Thailand (Trad, Surat Thani and Songkhla) and the Andaman Sea (Satun and Trang). The multilocus FST estimated at three nuclear loci revealed great and highly significant differentiation between the Gulf of Thailand and Andaman Sea (FST=0.203, P

Populations of marine organisms are potentially affected by numerous selective pressures such as temperature and salinity, or anthropogenic pressures such as xenobiotics that may preclude adaptation to particular habitats. Such selective pressures may also affect their demography. Examples include modifications of the population dynamics through shifts in growth rate, and in life history traits affecting fitness such as size or age of first reproduction. However, the documentation of variation in phenotypically plastic traits specific to distinct environments cannot be taken as the ultimate proof that natural selection has occurred. Measurement of the impact of selection and subsequent local adaptation of fish populations based exclusively on morphological or physiological characters is one of the most difficult things to achieve because it depends on the use of phenotypic characters that closely match the genotype. Molecular markers can help to overcome this problem and, under some circumstances, can record the footprints of selection. A combination of polymorphisms that are under selection and those that are not can provide complementary information. In this paper, we review how and why selection can be detected at the molecular level, using genetic markers analysed in a population genetic framework. We then report and discuss case studies in fish.

A mitochondrial and nuclear gene analysis allowed us to precise the taxonomical position of the two sympatric species of mice known to be present on Cyprus. One of them is the commensal house mouse M. m. domesticus, and the other revealed to be a new taxon that is a sister species of M. spicilegus and M. macedonicus. The new species is equidistant from each of these, the divergence dating around 0.5-1 Myr. Its origin either results from an ancient accidental colonisation of the island or from a recent transportation by the first epipalaeolithic settlers. In this last eventuality, the new species would also exist somewhere else in Asia Minor.

High silica ZSM-5 membranes have been grown on porous α-alumina supports via hydrothermal synthesis for CO2 sequestration from methane reforming processes. The optimized synthesis parameters for high silica ZSM-5 membranes, including gel composition and ageing, seed composition and deposition techniques, temperature, time, and membrane calcination parameters are discussed. The permeation characteristics of several membranes for gases present during methane reforming processes (H2, CO2, O2, CH4, N2 and CO) were measured, as well as for the test gases He and SF6. The permeance of CO2 is higher than that of the other gases and is between two and three times higher than that of the smaller He atoms or H2 molecules. The higher permeance of CO2 is likely due to enhanced surface diffusion. Membranes showed a decrease in CO2 permeation over time, which was partially regenerated after a heating cycle.

Polyoxoniobate chemistry, both in the solid state and in solution is dominated by [Nb6O19]8−, the Lindquist ion. Recently, we have expanded this chemistry through use of hydrothermal synthesis. The current publication illustrates how use of heteroatoms is another means of diversifying polyoxoniobate chemistry. Here we report the synthesis of Na8[Nb8Ti2O28]·34H2O [ 1 ] and its structural characterization from single-crystal X-ray data. This salt crystallizes in the P-1 space group (a=11.829(4) A, b=12.205(4) A, c=12.532(4) A, α=97.666(5)°, β=113.840(4)°, γ=110.809(4)°), and the decameric anionic cluster [Nb8Ti2O28]8− has the same cluster geometry as the previously reported [Nb10O28]6− and [V10O28]6−. Molecular modeling studies of [Nb10O28]6− and all possible isomers of [Nb8Ti2O28]8− suggest that this cluster geometry is stabilized by incorporating the Ti4+ into cluster positions in which edge-sharing is maximized. In this manner, the overall repulsion between edge-sharing octahedra within the cluster is minimized, as Ti4+ is both slightly smaller and of lower charge than Nb5+. Synthetic studies also show that while the [Nb10O28]6− cluster is difficult to obtain, the [Nb8Ti2O28]8− cluster can be synthesized reproducibly and is stable in neutral to basic solutions, as well.

Pearl production, based on the aquaculture of the blacklipped pearl oyster Pinctada margaritifera, is an essential economic activity in French Polynesia. Production relies almost exclusively on the collection of wild spat, which makes the activity very dependent on natural resources. A good knowledge of these resources is thus essential for the rational management of farmed and wild populations. In this study, we analysed the structure of genetic variability, in wild and farmed populations distributed on four atolls from the Tuamotu–Gambier archipelago using four anonymous nuclear loci. No genetic difference was observed among samples from wild populations collected from Northern Tuamotu to Southern Gambier. This suggests that large-scale dispersal, either due to the absence of barriers to natural larval migration, or to the transport of collected spat for pearl production. No significant differences were found between wild and adjacent farmed populations for the number of alleles and observed heterozygosity, which supports the conclusion

Two new ammonium templated gallophosphates have been synthesized solvothermally using mixtures of ethylene glycol and water as solvent. The structure of both phases was determined from X-ray powder diffraction data. [Ga(PO 4 )(OH)] − ·[NH 4 ] + (2D-GAPON) crystallizes in monoclinic symmetry, space-group P2 1 / m with cell parameters a =8.564(1) A, b =6.0387(8) A, c =4.4883(6) A, β =98.05(1)° and V =229.84(3) A 3 . Its two-dimensional structure consists of infinite anionic layers separated by ammonium cations. [Ga 2 (PO 4 ) 3 ] 3− ·3[NH 4 ] + (3D-GAPON) has monoclinic symmetry, space-group C2 / c , with unit cell dimensions a =13.462(2) A, b =10.301(1) A, c =8.992(1) A, β =111.28(1)° and V =1161.9(6) A 3 . Its three-dimensional structure contains constricted elliptical channels running along the c axis, which host the ammonium ions.

We present here the genetic structure existing among five samples of the spotted sea bass Dicentrarchus punctatus, and we compare it to what prevails in the common sea bass D. labrax, a congeneric species sampled on almost the same geographical range. A genetic distance tree inferred from the polymorphism at six microsatellite loci shows a distinct pattern for the two species. D. labrax samples appears to be genetically more homogeneous with a global Fst of 3% as compared to the 10% observed at D. punctatus, indicating a lesser level of gene flow in the latter species. While appearing more differentiated, D. punctatus presents no clear geographical organisation of its genetic variability in opposition to D. labrax samples. This allows us to propose this pair of closely relative species as a good candidate for the study by comparative analysis of the biological and/or historical factors affecting genetic differentiation in marine environment.

Using protein loci and DNA markers, we show by a multilocus genetic analysis that certain populations of the two sympatric mouse species Mus musculus domesticus and Mus spretus show clear signs of partial introgression. Given the sterility of F1 males and the known partial genetic incompatibilities between the genomes of the two species, our finding does not invalidate the biological species complex, but allows to think that very limited genetic exchanges remain possible even long after the divergence of taxa. This may have some consequences on the dynamics of certain kinds of invasive or advantageous DNAs like transposable elements or pathogen resistance genes.

Marine bivalves are known to have small N e / N ratios, both in wild and hatchery-propagated populations. This has been interpreted as the consequence of a high variance in reproductive success. However, how much of this variance could be attributed to pre-zygotic reproductive factors or to post-zygotic selection was not yet estimated. To estimate the relative effect of these factors, we have conducted a parentage analysis on two 5×5 outbred crosses of Pacific oyster, Crassostrea gigas , using a single microsatellite marker. This was made possible by the high polymorphism encountered at this locus and careful selection of progenitors according to their genotypes. Results show large variance in parental contributions at various developmental stages, leading to a strong reduction of experiment-wide effective population sizes. Segregation distortions fluctuating with time were also observed. Our results show that the observed variance in reproductive success can be attributed to three main factors: gamete quality, sperm–egg interaction and differential viability among genotypes. The comparison of two kinds of crosses, where sperm competition was allowed or not, allowed us to estimate a 20% decrease of the effective population size under sperm competition. A further decrease was observed from larval to juvenile stages. Taken together, the observed gametic, zygotic and genetic effects warn against using too limited a number of progenitors in breeding programmes.

ZSM-22 has been synthesized from a dry amorphous gel via vapor phase transport crystallization, as bulk crystalline powder as well as an un-supported membrane. Crystalline products were characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, chemical analysis, and thermal analysis. Catalytic testing was performed to demonstrate the membrane's ability to perform as an on-line catalyst. The ZSM-22 catalytic membrane showed 1-butene to isobutene conversions in excess of 60% with selectivites close to 40%, which compares well with conventionally synthesized bulk crystals.

A new 3D open-framework fluorogallophosphate, Ga5(PO4)5F4·2[N2C4H12], was synthesized solvothermally using either 1,4-diazabicyclo[2.2.2]octane or piperazine as a templating agent. The structure as determined from low-temperature (−105°C) X-ray single crystal diffraction is orthorhombic, with space group Pccn, a=12.232(2) A, b=12.268(2) A, c=16.392(3) A, V=2460 A3 and Z=4. The 3D framework is built-up by corner linked PO4 tetrahedra, GaO4F trigonal bipyramids and GaO4F2 octahedra. The building block of the structure is an hexameric unit of composition 0.5 [Ga(PO4)]5F4. The organic template molecules reside in cavities formed by the intersection of eight member channels running along [1 0 0] and irregular pores parallel to [0 0 1]. The crystalline framework remains stable up to 350°C under oxygen.

A new chromium coordination compound, guanidinium tetrafluoro(trans-)dipyridinechromate(III), has been synthesized in one step under mild solvothermal conditions. [CrF4(C5H5N)2]−·[CN3H6]+crystallizes in the monoclinic space group P21/n, with a=8.6054(8) A, b=13.3529(12) A, c=13.2952(12) A, and β=100.62(2)°. The structure consists of discrete guanidinium cations, CN3H6+, and tetrafluorodipyridinechromate anions, CrF4(C5H5N)2−.

This study compares theoretical and simulated properties of two estimators of fixation indices F(ST) for multiallelic data from a single locus. The estimators are due to Weir and Cockerham (straight theta(WC)) and to Robertson and Hill (;straight theta(RH)), respectively. Both estimators are linear combinations of biallelic estimators which differ in the way frequent and rare alleles are weighted. Consequently, their sampling properties differ as far as bias and variance are concerned. In the infinite island model at migration-drift equilibrium, in the case of one multiallelic locus, we analytically approximate the bias of the two estimators and show that;straight theta(WC) is nearly unbiased, whereas;straight theta(RH) is negatively biased. Hence, we propose a correction of bias of the latter. Moreover, we reexamine the properties of variance of the initial estimators: due to their construction, their variances are minimal, each over different parameter ranges,;straight theta(RH) performing better for low differentiation and;straight theta(WC) for high differentiation. These theoretical properties are confirmed by simulations, which show that our correction of bias of;straight theta(RH) performs well and does not affect its property of minimal variance for low differentiation. Hence, we advocate the use of;straight theta(WC) for high values of differentiation, and the use of;straight theta(RH), with our correction of bias, for low or moderate differentiation.

The synthesis of [Al13O4(OH)24(H2O)12]xMS2(x=0.02–0.05,M=Mo;x=0.02–0.055,M=W) was accomplished by a precipitative encapsulation technique using single layers ofMS2. The products were characterized by powder X-ray diffraction, energy dispersive spectroscopy (EDS), thermal gravimetric analysis (TGA),27Al MAS-NMR, room temperature electrical conductivity measurements, and surface area measurements. Powder X-ray diffraction patterns show an expansion of approximately 9.9 A.27Al MAS-NMR indicates that the cluster is intact between theMS2layers. One-dimensional electron density mapping and Rietveld refinement performed on the powder diffraction data show that the cluster is oriented with its C3symmetry axis perpendicular to the layers. The samples exhibit conductivity values from 3 to 14 S/cm. TGA shows that the cluster is completely stable to 100°C, and largely stable to 330°C. Surface area measurements suggest that the space between the clusters is not accessible.

Digestion by restriction enzymes has been carried out on polymerase chain reaction products of the mitochondrial DNA control region of round sardine (Sardinella aurita) samples coming from the Eastern Atlantic and the Mediterranean Sea. The results show i) that, though the habitat is continuous, there is no gene flow between the two basins where two genetically differentiated groups can be recognized, ii) that each basin is genetically homogeneous and, iii) that the haplotypic diversity in the Mediterranean is between two and three times smaller than that observed in the Atlantic. These results can hardly be explained by a recent colonization from the Eastern Atlantic. This suggests that, for S. aurita and some other species, the Mediterranean Sea is genetically little influenced by the Eastern Atlantic.

The BASSMAP consortium, funded by the European Union, has been set up to improve the understanding of the genome of European sea bass (Dicentrarchus labrax). The specific aim is to locate genes of known function on the physical map and to compare specific regions among perciforms. We have produced an F1 cross of outbred sea bass as mapping panel and a Bacterial Artificial Chromosome library (7× redundancy and 165 kb average insert size). End sequencing of the BAC library is in progress and a radiation hybrid panel is under construction.

To determine the origins of laboratory mice, the restriction patterns of mitochondrial DNAs (mtDNAs) from various strains were compared with those of relevant subspecies and/or races of Mus musculus. In most strains and substrains of laboratory mice examined (50/55), the cleavage patterns were identical to those of the European subspecies M. m. domesticus. Those that varied include two sublines of NZB, the strain NZC, and the Japanese strain RR. The NZB and NZC patterns were identical to that of the European subspecies M. m. brevirostris, which itself has restriction patterns similar to M. m. domesticus. On the other hand, the RR pattern was identical to M. m. molossinus-like mice trapped in Western China and slightly different from Japanese M. m. molossinus. These findings suggest that the strains NZB and NZC stemmed from a European founder stock which differed from the ancestral stocks of other laboratory strains and that the ancestral mice of the RR strain had been transported from China to Japan. Therefore, most laboratory strains of mice are derived from the European subspecies M. m. domesticus while M. m. brevirostris and M. m. molossinus have made minor contributions. M. m. musculus does not appear to have made any contribution.

We have isolated a cDNA recombinant plasmid (pA29) identified as encoding part of the ventricular muscle myosin light chain MLC1v. This cDNA contains a 300-base pair fragment which under conditions of moderate stringency shows specific hybridization to MLC1v mRNA with no detectable cross-hybridization with the mRNAs encoding the fast skeletal muscle isoforms MLC1F and MLC3F, or the atrial muscle isoform MLC1A. Under these conditions hybridization is seen with an abundant mRNA present in slow skeletal muscle (soleus) which is indistinguishable from ventricular MLC1V mRNA on the basis of size and of thermal stability of hybrids formed with plasmid pA29. The mouse MLC1V and MLC1S proteins are found to co-migrate on two-dimensional gels. We therefore conclude that these isoforms are the same and are encoded by the same mRNA. Analysis of mouse DNA has identified a single region of the genome which hybridizes to this same fragment of pA29. This region has been isolated in a recombinant phage and has been shown to contain a single gene showing homology with MLC1V mRNA by R-loop analysis. We therefore conclude that MLC1V and MLC1S are encoded by a single gene. The pattern of segregation of a restriction fragment length polymorphism identified for this gene between Mus musculus and Mus spretus has been followed in an F1 backcross between these two mouse species. The results show the MLC1V/MLC1S gene to be closely linked to a marker at the distal end of mouse chromosome 9.

SPE wild-derived inbred mice belonging to Mus spretus species can produce antibodies against γ 1 isotypic determinants, common to European mice belonging to the Mus subgenus, with the exception of the Mus spretus species. They are also able to produce antibodies which define a “new” Igh-4 allotypic specificity (designated Igh-4.4).

Five species of Mediterranean grey mullet (Mugilidae) belonging to three genera were screened for protein variation at sixteen enzymatic loci. Protein identities were computed and compared to that obtained from other taxa. The present taxonomical structure of the family is discussed on this basis.