Interactions between Plasmodium falciparum skeleton-binding protein 1 and the membrane skeleton of malaria-infected red blood cells

During development inside red blood cells (RBCs), Plasmodium falciparum malaria parasites export proteins that associate with the RBC membrane skeleton. These interactions cause profound changes to the biophysical properties of RBCs that underpin the often severe and fatal clinical manifestations of falciparum malaria. P. falciparum erythrocyte membrane protein 1 (PfEMP1) is one such exported parasite protein that plays a major role in malaria pathogenesis since its exposure on the parasitised RBC surface mediates their adhesion to vascular endothelium and placental syncytioblasts. En route to the RBC membrane skeleton, PfEMP1 transiently associates with Maurer\u27s clefts (MCs), parasite-derived membranous structures in the RBC cytoplasm. We have previously shown that a resident MC protein, skeleton-binding protein 1 (SBP1), is essential for the placement of PfEMP1 onto the RBC surface and hypothesised that the function of SBP1 may be to target MCs to the RBC membrane. Since this would require additional protein interactions, we set out to identify binding partners for SBP1. Using a combination of approaches, we have defined the region of SBP1 that binds specifically to defined sub-domains of two major components of the RBC membrane skeleton, protein 4.1R and spectrin. We show that these interactions serve as one mechanism to anchor MCs to the RBC membrane skeleton, however, while they appear to be necessary, they are not sufficient for the translocation of PfEMP1 onto the RBC surface. The N-terminal domain of SBP1 that resides within the lumen of MCs clearly plays an essential, but presently unknown role in this process

Malformation rate of the developing f ish embryo of Plectorhinchus cinctus to indicate marine environment qual ity

[摘要]：以养殖场培育的花尾胡椒鲷受精卵为实验材料测试了厦门西海域5 个站位的表层水水样对花尾胡椒 鲷受精卵的胚胎发育毒性,并运用GC2MS 手段分析了水样中的美国EPA 优控的16 种PAHs 组分的含量。结 果表明:3 号站位(厦门市工业和生活污水主要排放口的外侧) 和4 号站位(厦门西港的港区) 的水样对鱼卵的胚 胎发育的毒性最强;8 号站位(位于主航道并濒临嵩屿电厂) 的水样对鱼卵胚胎发育的毒性次之,1 号站位(湾 口) 和5 号站位(内港) 的水样对鱼卵的胚胎发育的毒性较小。水样中的PAHs 含量分析结果表明,仅用水样中 的PAHs 含量不能全面地反映水样对鱼卵胚胎发育的毒性。最后,对本实验方法应用于海洋环境生物监测的有 效性进行了探讨。[Abstract]:Cultured zygotes of Plectorhi nchus ci nct us were done to make test the toxicity of surface water samples in Western Xia2 men Sea Area. The results showed that the water samples at Station 3 (the outlet of industrial and domestic sewage of Xiamen City) and Station 4 (the major port area of Xiamen Island) were the most toxic , it would be revealed that the industrial and domestic sewage and port pollution were the major sources of pollutants. Station 8 (in the sea - route and nearby a big power plant) was less toxic. The toxicity at station 1 (the outlet of Western Xiamen Bay) and Station 5 (the inner port area) were the least . The results showed that it was useful to test the toxicity of water samples by the method. Simultaneously sixteen components of EPA priority PAHs in these samples were also measured by GC/ MS (SIM mode) . The sequence of the toxicity to zygotes and the sequence of the concentrations of total PAHs were not the same , since the factors influencing the toxicity to zygotes were complicated , it would be also revealed that the method was useful to indicate the total marine environment quality.国家自然科学基金资助项目(A20077023 ,C40106012

Forming-free colossal resistive switching effect in rare-earth-oxide Gd2 O3 films for memristor applications

The reproducible forming-free resistive switching (RS) behavior in rare-earth-oxide Gd2 O3 polycrystalline thin film was demonstrated. The characteristic of this forming-free RS was similar to that of other forming-necessary binary RS materials except that its initial resistance starts from not the high resistance state (HRS) but the low resistance state (LRS). An ultrahigh resistance switching ratio from HRS to LRS of about six to seven orders of magnitude was achieved at a bias voltage of 0.6 V. Mechanism analysis indicated that the existence of metallic Gd in the Gd2 O3 films plays an important role in the forming-free RS performance. Our work provides a novel material with interesting RS behavior, which is beneficial to deepen our understanding of the origin of RS phenomenon

Approach to Validating an Opsonophagocytic Assay for Streptococcus pneumoniae

Streptococcus pneumoniae (pneumococcus) polysaccharide serotype-specific antibodies that have opsonophagocytic activity are considered a primary mechanism of host defense against pneumococcal disease. In vitro opsonophagocytic assays (OPAs) with antibody and complement to mediate opsonophagocytic killing of bacteria have been designed and developed as an adjunct to the standardized serum immunoglobulin G antipneumococcal capsular polysaccharide enzyme immunoassay to assess the effectiveness of pneumococcal vaccines. OPA presents challenges for assay standardization and assay precision due to the multiple biologically active and labile components involved in the assay, including human polymorphonuclear leukocytes or cultured effector cells, bacteria, and complement. Control of these biologically labile components is critical for consistent assay performance. An approach to validating the performance of the assay in accordance with International Conference for Harmonization guidelines, including its specificity, intermediate precision, accuracy, linearity, and robustness, is presented. Furthermore, we established parameters for universal reagents and standardization of the use of these reagents to ensure the interlaboratory reproducibility and validation of new methodologies