The mammalian pseudoautosomal region

Despite being morphologically dissimilar, mammalian sex chromosomes pair in male meiosis. Molecular studies of the X and Y chromosomes in humans and mice have identified the pseudoautosomal region, a genetically unique region of shared, recombining sequences that fall within the meiotic pairing region. Complete meiotic and physical maps of the human pseudoautosomal region have been produced and the pseudoautosomal boundary has been cloned and sequenced. These studies have provided clues to mammalian sex chromosome function and evolution.     

Genetic polymorphisms ofQ region genes from wild-derived mice: Implications forQ region evolution

Both serological and DNA sequence analyses were performed to determine the extent of genetic polymorphism inQ region genes. A panel of Qa-2-specific monoclonal antibodies (mAbs) was tested on 35 wildderived and inbred mouse strains. Members of this reagent panel recognize multiple and distinct epitopes on the Qa-2-bearing molecule(s). Although quantitative variations in Qa-2 levels were observed, no structural polymorphisms were detected. All strains were either entirely positive or entirely negative with the complete set of reagents. Moreover, cell surface Qa-2 expression was not significantly affected by differences in age or sex of the mouse or cell cycle status. To confirm this apparent lack of genetic polymorphism, the polymerase chain reaction (PCR) technique was used to amplify a portion of the 3 end of theQ region genes,Q4 toQ9, from several independent wild-derived strains of mice. Sequence analysis of the amplified material revealed very little evidence of nucleotide divergence. All strains tested had aQ even DNA sequence identical to that ofQ6/Q8 in the B10 strain. Likewise, all tested strains had aQ odd DNA sequence identical toQ7/Q9 in the B10 strain. Two strains showed additionalQ even sequences, while all strains tested possessed additionalQ odd sequences. The observed lack of polymorphism suggests that theQ genes have evolved in a different manner fromH-2K andH-2D. Moreover, duplications of these genes appear to have arisen prior to nucleotide sequence divergence.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers M30896-30902.     

Var2CSA minimal CSA binding region is located within the N-terminal region

Var2CSA, a key molecule linked with pregnancy-associated malaria (PAM), causes sequestration of Plasmodium falciparum infected erythrocytes (PEs) in the placenta by adhesion to chondroitin sulfate A (CSA). Var2CSA possesses a 300 kDa extracellular region composed of six Duffy-binding like (DBL) domains and a cysteine-rich interdomain region (CIDRpam) module. Although initial studies implicated several individual var2CSA DBL domains as important for adhesion of PEs to CSA, new studies revealed that these individual domains lack both the affinity and specificity displayed by the full-length extracellular region. Indeed, recent evidence suggests the presence of a single CSA-binding site formed by a higher-order domain organization rather than several independent binding sites located on the different domains. Here, we search for the minimal binding region within var2CSA that maintains high affinity and specificity for CSA binding, a characteristic feature of the full-length extracellular region. Accordingly, truncated recombinant var2CSA proteins comprising different domain combinations were expressed and their binding characteristics assessed against different sulfated glycosaminoglycans (GAGs). Our results indicate that the smallest region within var2CSA with similar binding properties to those of the full-length var2CSA is DBL1X-3X. We also demonstrate that inhibitory antibodies raised in rabbit against the full-length DBL1X-6ε target principally DBL3X and, to a lesser extent, DBL5ε. Taken together, our results indicate that efforts should focus on the DBL1X-3X region for developing vaccine and therapeutic strategies aimed at combating PAM.     

DNA immunization with fusion genes containing HCV core region and HBV core region

The eucaryotic expression plasmids were constructed to express the complete (HCc191) or the truncated (HCc69 and HCc40) HCV core genes, solely or fused with the HBV core gene (HBc144). These constructions were transiently expressed in COS cells under the control of the CMV promoter. The antigenicity of HBc and HCc could be detected in the expression products by ELISA and Western blot. The mice immunized with these expression plasmids efficiently produced the anti-HCc antibodies, and also anti-HBc antibodies when the plasmids contained the fusion genes. In addition, the antibodies induced by the fusion genes were more persistent than those induced by the non-fusion HCV core genes. These indicate that the fusion of HCc genes to HBc gene is in favor of the immunogenicity of HCc, while the immunogenicity of HBc is not affected.     

Caveolin scaffolding region and the membrane binding region of SRC form lateral membrane domains

Formation of domains by the membrane binding motifs of caveolin and src were studied in large unilamellar vesicles using fluorescence digital imaging microscopy. Caveolin, a major structural protein of caveolae, contains a scaffolding region (residues 82-101) that contributes to the binding of the protein to the plasma membrane. A caveolin peptide (82-101) corresponding to this scaffolding region induced the formation of membrane domains enriched in the acidic lipids phosphatidylserine and phosphatidylinositol-4,5-bisphosphate. Cholesterol, another predominant component of caveolae, was also enriched in these domains. Caveolae also contain many different signaling molecules including src family tyrosine kinases. Src proteins bind to the plasma membrane via a N-terminal myristate chain and a cluster of basic residues that can interact electrostatically with negatively charged lipids. A peptide corresponding to the src membrane binding motifs (residues myr-2-19) sequestered acidic lipids into lateral membrane domains. Both the src and the caveolin peptides colocalized together with acidic lipids in the domains. Control experiments show the domains are not the result of vesicle aggregation. Two-photon fluorescence correlation spectroscopy experiments suggest diffusion in the domains was slower, but the domains were dynamic. Protein kinase C phosphorylated src in its N-terminal membrane binding region; however, the caveolin scaffolding peptide inhibited this activity. Consequently, protein-induced membrane domains may affect cell signaling by organizing signal transduction components within the membrane and changing reaction rates.     

A proline-rich region and nearby cysteine residues target XLalphas to the Golgi complex region

XLalphas is a splice variant of the heterotrimeric G protein, Galpha(s), found on Golgi membranes in cells with regulated and constitutive secretion. We examined the role of the alternatively spliced amino terminus of XLalphas for Golgi targeting with the use of subcellular fractionation and fluorescence microscopy. XLalphas incorporated [(3)H]palmitate, and mutation of cysteines in a cysteine-rich region inhibited this incorporation and lessened membrane attachment. Deletion of a proline-rich region abolished Golgi localization of XLalphas without changing its membrane attachment. The proline-rich and cysteine-rich regions together were sufficient to target the green fluorescent protein, a cytosolic protein, to Golgi membranes. The membrane attachment and Golgi targeting of the fusion protein required the putative palmitoylation sites, the cysteine residues in the cysteine-rich region. Several peripheral membrane proteins found at the Golgi have proline-rich regions, including a Galpha(i2) splice variant, dynamin II, betaIII spectrin, comitin, and a Golgi SNARE, GS32. Our results suggest that proline-rich regions can be a Golgi-targeting signal for G protein alpha subunits and possibly for other peripheral membrane proteins as well.     

Lipectomy of the ilio-lumbosacral region

In the past, several techniques for raising the gluteal mass have been described, all of which were based on dermolipectomies of major or minor extension. The main disadvantage of these dermolipectomies is the visible external scar. The author presents his technique for lipectomy of the ilio-lumbosacral region. It is proposed that multiplanar liposuction in this region lengthens the lumbar lordotic curve and results in upward traction on the buttocks, resulting in a more youthful contour of the region. The article describes a series of 98 patients with lipodystrophy of the ilio-lumbosacral area who underwent liposuction of the region and were highly satisfied with the results.     

Tuberculosis morbidity in Primor'e region

The present epidemiological situation in tuberculosis in the Maritime Territory is described, including the spread of this infection among the population and the prognosis for the next year. Tuberculosis morbidity in HIV-infected patients is specially emphasized, with high growth rate of morbidity in these mixed infections. The conclusion has been made on the necessity of improving the diagnostic and prophylactic measures among the population of the Maritime Territory.     

惠州地区氮流动力学分析

富营养化是重要的水体污染问题,氮素是富营养化形成的重要因素.采用物流核算的方法研究了中国惠州地区与人类活动有关的氮流在环境系统和人类生产生活系统的状况.采用非点源污染输出系数法定量研究氮流,城市生活污水中氮的排放采用人口氮素摄入 排放法来估算.对惠州地区1998年实测资料氮流过程的统计分析和动力学分析结果表明,该地区主要氮流动力学因素为河流输送、化学肥料和动物饲料输入、人类生产生活、大气氮的转化和沉降、动物排泄物降解挥发以及燃烧过程和其它散发过程中氮的损耗.当年输入本地区的氮素有40%滞留在系统中,这些氮素可能累积从而引发环境问题.河流是系统氮素输出的主要方式,约占57%.同多瑙河和长江流域的比较发现,这3个地区单位面积氮输出量相当,人均氮素贡献率接近.     

Staphylocoagulase-binding region in human prothrombin

A staphylocoagulase-binding region in human prothrombin was studied by utilizing several fragments prepared from prothrombin by limited proteolysis. Bovine prothrombin, prethrombin 1, prethrombin 2, and human diisopropylphosphorylated alpha-thrombin strongly inhibited formation of the complex ("staphylothrombin") between human prothrombin and staphylocoagulase, but bovine prothrombin fragment 1 and fragment 2 had no effect on the complex formation, indicating that the binding region of human prothrombin for staphylocoagulase is located in the prethrombin 2 molecule. To identify further the staphylocoagulase-binding region, human alpha-thrombin was cleaved into the NH2-terminal large fragment (Mr = 26,000) and the COOH-terminal fragment (Mr = 16,000) by porcine pancreatic elastase. Of these fragments, the COOH-terminal fragment, which includes Asn-200 to the COOH-terminal end of the alpha-thrombin molecule, partially inhibited the complex formation between staphylocoagulase and human prothrombin. In contrast, the NH2-terminal large fragment did not show any inhibitory effect on the staphylothrombin formation. These results suggest that the staphylocoagulase interacts with human prothrombin through the COOH-terminal region of alpha-thrombin B chain. Other plasma proteins, factor X, factor IX, protein C, protein S, protein Z, all of which are structurally similar to prothrombin, did not inhibit the staphylothrombin formation at all, indicating that a specific interaction site with staphylocoagulase is contained only in the prothrombin molecule.