637 research outputs found

    Identification of Multiple Domains of Entamoeba histolytica Intermediate Subunit Lectin-1 with Hemolytic and Cytotoxic Activities

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    Galactose and N-acetyl-D-galactosamine-inhibitable lectin of Entamoeba histolytica have roles in the pathogenicity of intestinal amoebiasis. Igl1, the intermediate subunit lectin-1 of E. histolytica, has been shown to have both hemolytic and cytotoxic activities that reside in the C-terminus of the protein. To identify the amino acid regions responsible for these activities, recombinant proteins were prepared and used in hemolytic and cytotoxic assays. The results revealed that Igl1 has multiple domains with hemolytic and cytotoxic activities and that amino acids 787-846, 968-1028 and 1029-1088 are involved in these activities. The hemolytic activities of the fragments were partly inhibited by mannose, galactose and N-acetylgalactosamine, and glucose showed lower or negligible inhibitory effects for the activities. This is the first report of a protozoan protein with hemolytic and cytotoxic activities in multiple domains

    Increase of S-100 protein-positive stellate cells in the anterior pituitary of chronic alcoholic patients with fatty liver or fatty cirrhosis.

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    Healthy subjects 40 years old were used as controls in a study of stellate cells (S-100 protein-containing cells, or S-100 cells) in subjects with chronic alcoholism and fatty liver or fatty cirrhosis. S-100 cells were sparsely found in the adenohypophysis of control subjects, and these cells sometimes formed small clusters. However, in chronic alcoholics with fatty liver or fatty cirrhosis, the number of stellate cells in the anterior pituitary tended to be 17 times higher than it was in the control group. No increase in the number of S-100 positive cells that constitute the large and small follicles in the intermediate pituitary. The physiological function of the S-100 protein has not yet been identified. The fact that an increase in prolactin-secreting and growth hormone-secreting cells, as well as a decrease in gonadotrophs were observed in the hypophysis of alcoholics suggests that the function of stellate cells may be closely related to these phenomena. Our results also imply that the stellate cells found in the anterior and intermediate pituitary differ in function although they both produce S-100 proteins.</p

    Performance based design of reinforced concrete beams under impact

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    金沢大学理工研究域環境デザイン学系The purpose of this research is to collect fundamental data and to establish a performance-based design method for reinforced concrete beams under perpendicular impact load. Series of low speed impact experiments using reinforced concrete beams were performed varying span length, cross section and main reinforcement. The experimental results are evaluated focusing on the impact load characteristics and the impact behaviours of reinforced concrete beams. Various characteristic values and their relationships are investigated such as the collision energy, the impact force duration, the energy absorbed by the beams and the beam response values. Also the bending performance of the reinforced concrete beams against perpendicular impact is evaluated. An equation is proposed to estimate the maximum displacement of the beam based on the collision energy and the static ultimate bending strength. The validity of the proposed equation is confirmed by comparison with experimental results obtained by other researchers as well as numerical results obtained by FEM simulations. The proposed equation allows for a performance based design of the structure accounting for the actual deformation due to the expected impact action. © Author(s) 2010

    Heat shock cognate protein 70 contributes to Brucella invasion into trophoblast giant cells that cause infectious abortion

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    <p>Abstract</p> <p>Background</p> <p>The cell tropism of <it>Brucella abortus</it>, a causative agent of brucellosis and facultative intracellular pathogen, in the placenta is thought to be a key event of infectious abortion, although the molecular mechanism for this is largely unknown. There is a higher degree of bacterial colonization in the placenta than in other organs and many bacteria are detected in trophoblast giant (TG) cells in the placenta. In the present study, we investigated mechanism of <it>B. abortus </it>invasion into TG cells.</p> <p>Results</p> <p>We observed internalization and intracellular growth of <it>B. abortus </it>in cultured TG cells. A monoclonal antibody that inhibits bacterial internalization was isolated and this reacted with heat shock cognate protein 70 (Hsc70). Depletion and over expression of Hsc70 in TG cells inhibited and promoted bacterial internalization, respectively. IFN-γ receptor was expressed in TG cells and IFN-γ treatment enhanced the uptake of bacteria by TG cells. Administering the anti-Hsc70 antibody to pregnant mice served to prevent infectious abortion.</p> <p>Conclusion</p> <p><it>B. abortus </it>infection of TG cells in placenta is mediated by Hsc70, and that such infection leads to infectious abortion.</p
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