An immunofluorescent method for identification of isolated thyrotropic cells

Summary A sensitive and specific immunofluorescent method for identification of thyrotropic cells was developed. The TSH-producing cells were found to be heterogenic in their morphology and intensity of staining.     

Analyses immunoélectrophorétiques des fractions protéiques du sérum humain séparées par électrophorèse en gel d'amidon

Summary Human plasma components, separated by starch gel electrophoresis, are eluted and concentrated by lyophilisation. Immuno-electrophoretic analysis shows that certain of these fractions are immunologically heterogenous. The authors point out that this immunological criterium should be used before employing an eluted fraction, even if it appears electrophoretically homogenous.      

ATR/ATM-mediated phosphorylation of human Rad17 is required for genotoxic stress responses.

Genotoxic stress triggers the activation of checkpoints that delay cell-cycle progression to allow for DNA repair. Studies in fission yeast implicate members of the Rad family of checkpoint proteins, which includes Rad17, Rad1, Rad9 and Hus1, as key early-response elements during the activation of both the DNA damage and replication checkpoints. Here we demonstrate a direct regulatory linkage between the human Rad17 homologue (hRad17) and the checkpoint kinases, ATM and ATR. Treatment of human cells with genotoxic agents induced ATM/ATR-dependent phosphorylation of hRad17 at Ser 635 and Ser 645. Overexpression of a hRad17 mutant (hRad17AA) bearing Ala substitutions at both phosphorylation sites abrogated the DNA-damage-induced G2 checkpoint, and sensitized human fibroblasts to genotoxic stress. In contrast to wild-type hRad17, the hRad17AA mutant showed no ionizing-radiation-inducible association with hRad1, a component of the hRad1-hRad9-hHus1 checkpoint complex. These findings demonstrate that ATR/ATM-dependent phosphorylation of hRad17 is a critical early event during checkpoint signalling in DNA-damaged cells.     

用于万维网内容挖掘的图论技术

本书是由新加坡世界科技出版公司出版的《机器感知与人工智能》丛书的第62卷。图形是用来表示某些具有结构（即关系）信息的物体或系统的数据结构。图形应用于许多领域，从软件工程到人工智能。但是与最为流行的矢量模型相比，在机器学习中图形的利用则是有限的．但矢量模型未能捕获结构信息。     

Conservation of the D-mannose-adhesion protein among type 1 fimbriated members of the family Enterobacteriaceae

A variety of genera and species of the family Enterobacteriaceae bear surface fimbriae that enable them to bind to D-mannose residues on eukaryotic cells. Until recently, it was thought that the D-mannose binding site was located in the major structural subunit (FimA), of relative molecular mass (Mr) 17,000 (17 K), of these organelles in Escherichia coli. New evidence indicates that this binding site resides instead in a minor protein Mr 28-31 K (FimH) located at the tips and at long intervals along the length of the fimbriae, and is reminiscent of the minor tip adhesion proteins of pyelonephritis-associated pili (Pap) and S fimbriae. In contrast to the antigenic heterogeneity of the major FimA subunit, the antigenic structure of FimH is conserved among different strains of E. coli. Here, we report an even broader conservation of this minor adhesion protein extending to other genera and species of type 1 fimbriated Enterobacteriaceae. Our results may have implications for the development of broadly protective vaccines against Gram-negative bacillary infections in animals and perhaps in man.     

Asymmetric relationships between homosynaptic long-term potentiation and heterosynaptic long-term depression

All synaptically-based neuropsychological theories of learning postulate that there are changes resulting from neural activity which are long-lasting and confined to specific sets of synapses. In the past decade a form of synaptic strengthening known as long-term potentiation (LTP) has been found which results from high-frequency neural activity and is of sufficient duration to model as a learning mechanism. Some early tests of the synaptic specificity of LTP in area CA1 of the hippocampus indicated that although LTP was specific to the tetanized pathway, in a converging untetanized pathway it was associated with depression of synaptic transmission lasting for at least 30 min. However, others have found that this heterosynaptic depression more usually decays within 5-15 min post-tetanus despite the maintenance of LTP in the tetanized pathway. Similarly, in the dentate gyrus (DG), LTP of either the lateral (LPP) or medial (MPP) components of the perforant path afferents has been associated with only short-lasting reciprocal heterosynaptic depression. Here, using more detailed measurement of stimulus intensity curves, we report that tetanization of either MPP or LPP reliably depresses synaptic transmission in the other pathway for at least 3 h. This heterosynaptic depression, considerably smaller than the usual magnitude of LTP, was obtained regardless of whether LTP had been produced in the tetanized homosynaptic pathway. Heterosynaptic long-term depression was not observed if the test pathway had been previously tetanized.     

Emericid,a new polyether antibiotic fromStreptomyces hygroscopicus (DS 24 367)

Summary Emericid is a new polyether polycyclic ionophore antibiotic excreted byStreptomyces hygroscopicus (DS 24 367). Active in vitro against Gram-positive bacteria, it is ineffective in vivo. At a 0.006–0.02% level in the diet it protects chickens and rabbits against coccidiosis.From a recent paper byN. Otake (Tetrahedron Lett.1970, 4147) emericid and lonomycin would be identical.