The impact of the Scheldt input on the trace metal distribution in the Belgian coastal area (results of 1981–1983 and 1995–1996)

Offshore fluxes of Cu, Zn, Cd, Pb and Hg were calculated based onresidual flow patterns and salinity gradients along the Belgian coast. Theresidual flow lines along the Belgian coast are more or less parallel to thecoast except in the area where the north-easterly flowing watermass comingfrom the Channel encounters the south-westerly-oriented Scheldt outflow,forming a residual hydrodynamical front. From the steady-state salinitypattern, diffusion coefficients perpendicular to the residual flow werededuced; they ranged from 21 to 108 m² s^-1. Offshore fluxes of dissolved and particulate trace metals based on diffusiveand mixing processes are calculated. The steady state profiles of dissolvedmetals show a dilution effect in the coastal waters, reaching an almostconstant concentration in the marine watermass in the 1981–1983dataset. The ratios of the Scheldt input of trace metals to the totaldissolved offshore flux vary from 38 to 55% (1981–1983),depending on the kind of metal, and from 55 to 91% (1995–1996).The ratio of the Scheldt input to the dissolved metal flow parallel to thecoast, is in both periods (1981–1983 and 1995–1996), smallerthan 1%. The steady-state concentration profiles of particular metalsversus salinity are fairly constant in the coastal-estuarine and marinewatermasses, but decrease very abruptly from the first to the secondwatermass. Assuming a conservative behaviour of the particular metals,offshore fluxes and the resulting concentration increases agree fairly wellwith the observed values. The ratios of the Scheldt input to the particulatetrace metal offshore flux vary between 30 to 46% (1981–1983)and 13 to 37% (1995–1996). The contribution of the Scheldtestuary to the flows parallel to the coast ranges from 1.6 to 2.9%(1981–1983) and from 0.6 to 1.6% (1995). This revised version was published online in July 2006 with corrections to the Cover Date.     

China,Vietnam, and the South China Sea: Disputes and Dispute Management

This article examines recent developments in the South China Sea; in particular, the China-Vietnam relationship. The developments are presented in the broader context of the Sino-Vietnamese approach to managing border disputes since full normalization of relations in late 1991. The challenges for China and Vietnam in managing their disputes and related tension in the South China Sea are also discussed.     

Identifying Plasmodium falciparum cytoadherence-linked asexual protein 3 (CLAG 3) sequences that specifically bind to C32 cells and erythrocytes

Adhesion of mature asexual stage Plasmodium falciparum parasite-infected erythrocytes (iRBC) to the vascular endothelium is a critical event in the pathology of Plasmodium falciparum malaria. It has been suggested that the clag gene family is essential in cytoadherence to endothelial receptors. Primers used in PCR and RT-PCR assays allowed us to determine that the gene encoding CLAG 3 (GenBank accession no. NP_473155) is transcribed in the Plasmodium falciparum FCB2 strain. Western blot showed that antisera produced against polymerized synthetic peptides from this protein recognized a 142-kDa band in P. falciparum schizont lysate. Seventy-one 20-amino-acid-long nonoverlapping peptides, spanning the CLAG 3 (cytoadherence-linked asexual protein on chromosome 3) sequence were tested in C32 cell and erythrocyte binding assays. Twelve CLAG peptides specifically bound to C32 cells (which mainly express CD36) with high affinity, hereafter referred to as high-affinity binding peptides (HABPs). Five of them also bound to erythrocytes. HABP binding to C32 cells and erythrocytes was independent of peptide charge or peptide structure. Affinity constants were between 100 nM and 800 nM. Cross-linking and SDS-PAGE analysis allowed two erythrocyte binding proteins of around 26 kDa and 59 kDa to be identified, while proteins of around 53 kDa were identified as possible receptor sites for C-32 cells. The HABPs' role in Plasmodium falciparum invasion inhibition was determined. Such an approach analyzing various CLAG 3 regions may elucidate their functions and may help in the search for new antigens important for developing antimalarial vaccines.     

Lis1 and Ndel1 influence the timing of nuclear envelope breakdown in neural stem cells

Lis1 and Ndel1 are essential for animal development. They interact directly with one another and with cytoplasmic dynein. The developing brain is especially sensitive to reduced Lis1 or Ndel1 levels, as both proteins influence spindle orientation, neural cell fate decisions, and neuronal migration. We report here that Lis1 and Ndel1 reduction in a mitotic cell line impairs prophase nuclear envelope (NE) invagination (PNEI). This dynein-dependent process facilitates NE breakdown (NEBD) and occurs before the establishment of the bipolar spindle. Ndel1 phosphorylation is important for this function, regulating binding to both Lis1 and dynein. Prophase cells in the ventricular zone (VZ) of embryonic day 13.5 Lis1^+/− mouse brains show reduced PNEI, and the ratio of prophase to prometaphase cells is increased, suggesting an NEBD delay. Moreover, prophase cells in the VZ contain elevated levels of Ndel1 phosphorylated at a key cdk5 site. Our data suggest that a delay in NEBD in the VZ could contribute to developmental defects associated with Lis1–Ndel1 disruption.     

Bayesian Nonparametric Estimation of the Probability of Discovering New Species

We consider the problem of evaluating the probability of discoveringa certain number of new species in a new sample of populationunits, conditional on the number of species recorded in a basicsample. We use a Bayesian nonparametric approach. The differentspecies proportions are assumed to be random and the observationsfrom the population exchangeable. We provide a Bayesian estimator,under quadratic loss, for the probability of discovering newspecies which can be compared with well-known frequentist estimators.The results we obtain are illustrated through a numerical exampleand an application to a genomic dataset concerning the discoveryof new genes by sequencing additional single-read sequencesof cdna fragments.     

Implications of Exclusive Economic Zone Management and Regional Cooperation Between South Pacific Small Midocean Island Commonwealth Territories

The South China Sea has long been regarded as a major source of tension and instability in Pacific Asia. Since 1990, many bilateral and multilateral efforts to manage the possible conflicts in the region have been recorded. The purpose of this article is to analyze and assess the progress made in terms of conflict management among the claimants.     

Identifying Plasmodium falciparum EBA-175 homologue sequences that specifically bind to human erythrocytes

Erythrocyte binding antigen-160 (EBA-160) protein is a Plasmodium falciparum antigen homologue from the erythrocyte binding protein family (EBP). It has been shown that the EBP family plays a role in parasite binding to the erythrocyte surface. The EBA-160 sequence has been chemically synthesised in seventy 20-mer sequential peptides covering the entire 3D7 protein strain, each of which was tested in erythrocyte binding assays to identify possible EBA-160 functional regions. Five EBA-160 high activity binding peptides (HABPs) specifically binding to erythrocytes with high affinity were identified. Dissociation constants lay between 200 and 460 nM and Hill coefficients between 1.5 and 2.3. Erythrocyte membrane protein binding peptide cross-linking assays using SDS-PAGE showed that these peptides bound specifically to 12, 28, and 44 kDa erythrocyte membrane proteins. The nature of these receptor sites was studied in peptide binding assays using enzyme-treated erythrocytes. HABPs were able to block merozoite in vitro invasion of erythrocytes. HABPs’ potential as anti-malarial vaccine candidates is also discussed.     

Identification of three gp350/220 regions involved in Epstein-Barr virus invasion of host cells

Epstein-Barr virus (EBV) invasion of B-lymphocytes involves EBV gp350/220 binding to B-lymphocyte CR2. The anti-gp350 monoclonal antibody (mAb)-72A1 Fab inhibits this binding and therefore blocks EBV invasion of target cells. However, gp350/220 regions interacting with mAb 72A1 and involved in EBV invasion of target cells have not yet been identified. This work reports three gp350/220 regions, defined by peptide 11382, 11389, and 11416 sequences, that are involved in EBV binding to B-lymphocytes. Peptides 11382, 11389, and 11416 bound to CR2(+) but not to CR2(-) cells, inhibited EBV invasion of cord blood lymphocytes (CBLs), were recognized by mAb 72A1, and inhibited mAb 72A1 binding to EBV. Peptides 11382 and 11416 binding to peripheral blood lymphocytes (PBLs) induced interleukin-6 protein synthesis in these cells, this phenomenon being inhibited by mAb 72A1. The same behavior has been reported for gp350/220 binding to PBLs. Anti-peptide 11382, 11389, and 11416 antibodies inhibited EBV binding and EBV invasion of PBLs and CBLs. Peptide 11382, 11389, and 11416 sequences presented homology with the C3dg regions coming into contact with CR2 (C3dg and gp350 bound to similar CR2 regions). These peptides could be used in designing strategies against EBV infection.     

Amino terminal peptides from the Plasmodium falciparum EBA-181/JESEBL protein bind specifically to erythrocytes and inhibit in vitro merozoite invasion

Several EBA-175 paralogues (EBA-140, EBA-165, EBA-175, EBA-181, and EBL-1) have been described among the Plasmodium falciparum malaria parasite proteins, which are important in the red blood cell (RBC) invasion process. EBA-181/JESEBL is a 181 kDa protein expressed in the late schizont stage and located in the micronemes; it belongs to the Plasmodium Duffy binding-like family and is able to interact with the erythrocyte surface. Here, we describe the synthesis of 78, 20-mer synthetic peptides derived from the reported EBA-181/JESEBL sequence and their ability to bind RBCs in receptor-ligand assays. Five peptides (numbered 30030, 30031, 30045, 30051, and 30060) displayed high specific binding to erythrocytes; their equilibrium binding parameters were then determined. These peptides interacted with 53 and 33 kDa receptor proteins on the erythrocyte surface, this binding being altered when RBCs were pretreated with enzymes. They were able to inhibit P. falciparum merozoite invasion of RBCs when tested in in vitro assays. According to these results, these five EBA-181/JESEBL high specific erythrocyte binding peptides, as well as the entire protein, were seen to be involved in the molecular machinery used by the parasite for invading RBCs. They are thus suggested as potential candidates in designing a multi-sub-unit vaccine able to combat the P. falciparum malaria parasite.