中国斑翅跳小蜂属一新种(膜翅目,跳小蜂科)

记述了育自上海桃树上1种盾蚧中的斑翅跳小蜂属1新种:上海斑翅跳小蜂Epitetracnemus shanghaiensis sp.nov..文中给出了新种的形态特征图和该属分种检索表.研究标本保存于中国科学院上海生命科学研究院植物生理生态研究所.     

Chondroitin sulfate A-adhering Plasmodium falciparum-infected erythrocytes express functionally important antibody epitopes shared by multiple variants

Acquired protection from Plasmodium falciparum placental malaria, a major cause of maternal, fetal, and infant morbidity, is mediated by IgG specific for the P. falciparum erythrocyte membrane protein 1 variant VAR2CSA. This protein enables adhesion of P. falciparum-infected erythrocytes to chondroitin sulfate A in the intervillous space. Although interclonal variation of the var2csa gene is lower than that among var genes in general, VAR2CSA-specific Abs appear to target mainly polymorphic epitopes. This has raised doubts about the feasibility of VAR2CSA-based vaccines. We used eight human monoclonal IgG Abs from affinity-matured memory B cells of P. falciparum-exposed women to study interclonal variation and functional importance of Ab epitopes among placental and peripheral parasites from East and West Africa. Most placental P. falciparum isolates were labeled by several mAbs, whereas peripheral isolates from children were essentially nonreactive. The mAb reactivity of peripheral isolates from pregnant women indicated that some were placental, whereas others had alternative sequestration foci. Most of the mAbs were comparable in their reactivity with bound infected erythrocytes (IEs) and recombinant VAR2CSA and interfered with IE and/or VAR2CSA binding to chondroitin sulfate A. Pair-wise mAb combinations were more inhibitory than single mAbs, and all of the mAbs together was the most efficient combination. Each mAb could opsonize IEs for phagocytosis, and a combination of the eight mAbs caused phagocytosis similar to that of plasma IgG-opsonized IEs. We conclude that functionally important Ab epitopes are shared by the majority of polymorphic VAR2CSA variants, which supports the feasibility of VAR2CSA-based vaccines against placental malaria.     

优化萝卜基因组DNA RAPD-PCR反应体系的正交设计法

以CTAB微量提取方法提取10个红萝卜雄性不育系A单株的基因组DNA,等浓度混合成基因池。以其为模板,用正交设计方法论定RAPD-PCR反应体系的各影响因子,用随机引物S42（5’GGACCCAACC3’）优化萝卜雄性不育系A基因组DNARAPD,PCR反应体系,16次试验即可获得最佳的RAPD-PCR反应体系。     

Rap1A-deficient T and B cells show impaired integrin-mediated cell adhesion

Studies in tissue culture cells have demonstrated a role for the Ras-like GTPase Rap1 in the regulation of integrin-mediated cell-matrix and cadherin-mediated cell-cell contacts. To analyze the function of Rap1 in vivo, we have disrupted the Rap1A gene by homologous recombination. Mice homozygous for the deletion allele are viable and fertile. However, primary hematopoietic cells isolated from spleen or thymus have a diminished adhesive capacity on ICAM and fibronectin substrates. In addition, polarization of T cells from Rap1-/- cells after CD3 stimulation was impaired compared to that of wild-type cells. Despite this, these defects did not result in hematopoietic or cell homing abnormalities. Although it is possible that the relatively mild phenotype is a consequence of functional complementation by the Rap1B gene, our genetic studies confirm a role for Rap1A in the regulation of integrins.     

Compartmentalization directs assembly of the signal recognition particle

Many ribonucleoprotein complexes assemble stepwise in distinct cellular compartments, a process that usually involves bidirectional transport of both RNA and proteins between the nucleus and cytoplasm. The biological rationale for such complex transport steps in RNP assembly is obscure. One important example is the eukaryotic signal recognition particle (SRP), a cytoplasmic RNP consisting of one RNA and six proteins. Prior in vivo studies support an "SRP54-late" assembly model in which all SRP proteins, except SRP54, are imported from the cytoplasm to the nucleus to bind SRP RNA. This partially assembled complex is then exported to the cytoplasm where SRP54 binds and forms the SRP holocomplex. Here we show that native SRP assembly requires segregated and ordered binding by its protein components. A native ternary complex forms in vitro when SRP19 binds the SRP RNA prior to binding by SRP54, which approximates the eukaryotic cellular pathway. In contrast, the presence of SRP54 disrupts native assembly of SRP19, such that two RNA-binding loops in SRP19 misfold. These results imply that SRP54 must be sequestered during early SRP assembly steps, as apparently occurs in vivo, for proper assembly of the SRP to occur. Our findings emphasize that spatial compartmentalization provides an additional level of regulation that prevents competition among components and can function to promote native assembly of the eukaryotic SRP.     

Plasmodium falciparum: chondroitin sulfate A is the major receptor for adhesion of parasitized erythrocytes in the placenta

Plasmodium falciparum parasites that sequester in the placenta bind to the molecule chondroitin sulfate A (CSA). Women become resistant to malaria during pregnancy as they acquire antibodies that inhibit parasite adhesion to CSA, suggesting that a vaccine against placental malaria is feasible. Hyaluronic acid (HA) and non-immune IgG have also been proposed as receptors for P. falciparum adhesion in the placenta, but evidence for their roles is inconclusive. In this study, CSA, HA, and IgG were simultaneously assessed for their relative contributions to placental adhesion. Placental parasites collected in Tanzania uniformly adhered to the molecule CSA, and soluble CSA completely inhibited adhesion of most samples to placental cryosections. Three of 46 placental parasite samples also adhered to immobilized HA, but HA failed to inhibit adhesion of any placental parasites to placental cryosections. Similarly, non-immune IgG and protein A failed to inhibit adhesion of parasite samples to placental cryosection. P. falciparum adhesion in the placenta appears to be a non-redundant process that requires CSA as a receptor. Vaccines that elicit functional antibodies against CSA-binding parasites may confer resistance to pregnancy malaria.     

Echinostoma caproni: intestinal pathology in the golden hamster, a highly compatible host, and the Wistar rat, a less compatible host

The histopathological changes induced by Echinostoma caproni (Trematoda: Echinostomatidae) in a high (golden hamster) and a low compatible host (rat) were compared at 15 and 30 days post-infection. Infection of rats was characterized by a progressive increase in erosion of villi and elevated numbers of goblet cells, which could be related to the early expulsion of the parasite in a host of low compatibility. In contrast to rats, the number of goblet cell in E. caproni-infected hamsters was low, but increased numbers of neutrophils and mesenteric inflammatory cells were observed. This indicated that local inflammatory responses in hamsters were greater than in rats. An immunohistochemical study using polyclonal IgG anti-E. caproni excretory-secretory antigens demonstrated a greater level of passage of E. caproni antigens through the intestinal mucosa in hamsters than in rats, probably in relation to the greater inflammatory response. Our results indicate the fact that early inflammatory responses could be important for the establishment of E. caproni chronic infections in highly compatible hosts.     

Residues in the hendra virus fusion protein transmembrane domain are critical for endocytic recycling

Hendra virus is a highly pathogenic paramyxovirus classified as a biosafety level four agent. The fusion (F) protein of Hendra virus is critical for promoting viral entry and cell-to-cell fusion. To be fusogenically active, Hendra virus F must undergo endocytic recycling and cleavage by the endosomal/lysosomal protease cathepsin L, but the route of Hendra virus F following internalization and the recycling signals involved are poorly understood. We examined the intracellular distribution of Hendra virus F following endocytosis and showed that it is primarily present in Rab5- and Rab4-positive endosomal compartments, suggesting that cathepsin L cleavage occurs in early endosomes. Hendra virus F transmembrane domain (TMD) residues S490 and Y498 were found to be important for correct Hendra virus F recycling, with the hydroxyl group of S490 and the aromatic ring of Y498 important for this process. In addition, changes in association of isolated Hendra virus F TMDs correlated with alterations to Hendra virus F recycling, suggesting that appropriate TMD interactions play an important role in endocytic trafficking.     

A plasma survey using 38 PfEMP1 domains reveals frequent recognition of the Plasmodium falciparum antigen VAR2CSA among young Tanzanian children

PfEMP1 proteins comprise a family of variant antigens that appear on the surface of P. falciparum-infected erythrocytes and bind to multiple host receptors. Using a mammalian expression system and BioPlex technology, we developed an array of 24 protein constructs representing 38 PfEMP1 domains for high throughput analyses of receptor binding as well as total and functional antibody responses. We analyzed the reactivity of 561 plasma samples from 378 young Tanzanian children followed up to maximum 192 weeks of life in a longitudinal birth cohort. Surprisingly, reactivity to the DBL5 domain of VAR2CSA, a pregnancy malaria vaccine candidate, was most common, and the prevalence of reactivity was stable throughout early childhood. Reactivity to all other PfEMP1 constructs increased with age. Antibodies to the DBL2βC2(PF11_0521) domain, measured as plasma reactivity or plasma inhibition of ICAM1 binding, predicted reduced risk of hospitalization for severe or moderately severe malaria. These data suggest a role for VAR2CSA in childhood malaria and implicate DBL2βC2(PF11_0521) in protective immunity.