Function-blocking antibodies to human vascular adhesion protein-1: a potential anti-inflammatory therapy

Human vascular adhesion protein-1 (VAP-1) is a homodimeric 170-kDa sialoglycoprotein that is expressed on the surface of endothelial cells and functions as a semicarbazide-sensitive amine oxidase and as an adhesion molecule. Blockade of VAP-1 has been shown to reduce leukocyte adhesion and transmigration in in vivo and in vitro models, suggesting that VAP-1 is a potential target for anti-inflammatory therapy. In this study we have constructed mouse-human chimeric antibodies by genetic engineering in order to circumvent the potential problems involved in using murine antibodies in man. Our chimeric anti-VAP-1 antibodies, which were designed to lack Fc-dependent effector functions, bound specifically to cell surface-expressed recombinant human VAP-1 and recognized VAP-1 in different cell types in tonsil. Furthermore, the chimeric antibodies prevented leukocyte adhesion and transmigration in vitro and in vivo. Hence, these chimeric antibodies have the potential to be used as a new anti-inflammatory therapy.     

Vp130, a chloroviral surface protein that interacts with the host Chlorella cell wall

A protein, Vp130, that interacts with the host cell wall was isolated from Chlorovirus CVK2. From its peptide sequence, the gene for Vp130 was identified on the PBCV-1 genomic sequence as an ORF combining A140R and A145R. In Vp130, the N-terminus was somehow modified and the C-terminus was occupied by 23-26 tandem repeats of a PAPK motif. In the internal region, Vp130 contained seven repeats of 70-73 amino acids, each copy of which was separated by PAPK sequences. This protein was well conserved among NC64A viruses. A recombinant rVp130N protein formed in Escherichia coli was shown not only to bind directly to the host cell wall in vitro but also to specifically bind to the host cells, as demonstrated by fluorescence microscopy. Because externally added rVp130N competed with CVK2 to bind to host cells, Vp130 is most likely to be a host-recognizing protein on the virion.     

Orientation of the peptidoglycan chains in the sacculus of Escherichia coli

The organization of chains of oligopeptidoglycan in the saccular wall is of critical importance in the study of the mechanism and physiology of prokaryotic wall growth. The electron microphotographs of De Pedro et al, present new findings and can be used to negate or at least raise questions about the previously accepted conclusion that the glycan chains are oriented transversely to the axis of rod-shaped Escherichia coli. This suggests caution in assuming that the glycan chains in the murein structure are parallel to each other and are perpendicular to the axis of the cell.These results should reopen the question of not only the orientation of the peptidoglycan chains, but the possibility of variability in orientation. Three classes of hypotheses about wall growth are reconsidered and problems with them are presented. The new results from De Pedro's laboratory and the experimental glycan chain length distribution argue against proposed systematic models. These include models that postulate belts or hoops stretched around the circumference of the cell and mechanisms that insert new chains of the length of presumptive “docking” strands in the stress-bearing wall. They are consistent, however, with the surface stress theory that proposes that random enzyme action together with physical forces are involved in the elongation of the rod-shaped Gram-negative wall.     

A simple device to aid impalement of cells using conventional microelectrode drives

Consistent penetration of cell membranes by micropipettes is facilitated by using electrode accelerators or high velocity step drives. Notwithstanding, much intracellular work is still done with conventional mechanical or hydraulic drives; cell membrane penetration is achieved by means of gentle taps on any convenient part of the set up. A remote control device is described which performs this function and is compact enough to be fixed on either the microelectrode holder or the preparation mounting. It consists of a small magnetized rod freely suspended in a pot-core coil. A current pulse through the coil jolts the rod; the inertial reaction of the coil frame provides the sudden movement required by the micropipette tip to overcome the elastic resistance of the cell membrane.     

Molecular mechanisms of virus-induced carcinogenesis: the interaction of viral factors with cellular tumor suppressor proteins

Accumulating evidence indicates that tumor viruses represent a major etiological factor in a significant portion of human cancers. These cancers include human papillomavirus induced anogenital cancers, hepatitis B and C virus associated hepatocellular carcinomas, nasopharyngeal carcinomas and lymphomas linked to Epstein-Barr virus infection, and human T cell leukemia virus associated adult T cell leukemias. This review summarizes the recent progress made in understanding the molecular mechanisms of viral carcinogenesis, with a particular focus on the interaction of viral factors with cellular tumor suppressor proteins. The functional inactivation of tumor suppressor proteins may represent a common strategy by which several tumor viruses contribute to malignant cell transformation.Abbreviations EBV Epstein-Barr virus - E6AP E6-associated protein - HBV Hepatitis B virus - HCC Hepatocellular carcinoma - HPV Human papillomavirus - HTLV Human T cell leukemia virus - pRb Retinoblastoma protein - RB Retinoblastoma - SV40 Simian virus 40     

音猬因子的功能受体斑片在培养神经干细胞中的表达

目的　观察在培养的神经干细胞内是否有发育调控分子———音猬因子 (sonichedgehog)功能受体———斑片 (patched)表达。　方法　神经干细胞克隆在体外培养传代后 ,用patched的特异性引物对培养的神经干细胞进行RT PCR分析 ,PCR产物经克隆测序后 ,用地高辛标记克隆的探针 ,对神经干细胞进行原位杂交分析。　结果　神经干细胞克隆内大量的细胞均可表达sonichedgehog的功能受体patched ,patched阳性细胞间未见明显差别 ,克隆边缘与中央的patched分布也未见明显差别。　结论　sonichedgehog信号传导路可能在神经干细胞的增殖与分化过程中起重要作用。     

Isolation of a Toxoplasma gondii cyclin by yeast two-hybrid interactive screen

GAL4-based yeast two-hybrid cDNA libraries from Toxoplasma gondii RH strain were constructed and screened for interactors of a putative T. gondii cdc2-related kinase, TgCRK2. A screen of 3.2 million transformants yielded a single yeast clone that harbored a protein fusion capable of specifically interacting with TgCRK2. Sequencing revealed the cDNA insert (TgCYC1) had homology to the cyclin class of proteins. The TgCYC1 cDNA fragment was used to probe a conventional T. gondii cDNA library and a 2.65 kb cDNA coding for a predicted protein of 582 amino acids was obtained. Based on comparison with a 5'-RACE product from tachyzoite mRNA, the 2.65 kb cDNA for TgCYC1 appeared to be complete. TgCYC1 had the highest similarity to Plasmodium falciparum CYC1 and displayed sequence characteristics that place it in the cyclin H class of eukaryotic cyclins. In synchronous tachyzoite populations the level of TgCYC1 mRNA was unchanged indicating it is not cell cycle regulated at the mRNA level. TgCYC1 rescues the G(1)/S cyclin cell cycle defect in S. cerevisiae strain DL1 demonstrating that this apicomplexan cyclin can function in an established heterologous model system.