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Biomedical subjects

J E Manning

Publications and source records attributed to J E Manning.

79 records · Page 5Linked to original sources
PubMed1971

Circular chloroplast DNA from Euglena gracilis.

Chloroplast DNA of the protozoan flagellate, Euglena gracilis, exists as circular molecules, 40 mum in contour length, as shown by electron microscopy and buoyant density analyses.

Cell Fractionation↗
PubMedDate not supplied

Cloning of a major surface-antigen gene of Trypanosoma cruzi and identification of a nonapeptide repeat.

The parasitic protozoan Trypanosoma cruzi can establish infection in humans and other vertebrate hosts through direct penetration of host cells by trypomastigotes transmitted by the insect vector. Although the molecular processes involved in trypomastigote interiorization of vertebrate cells are unknown, several studies suggest that surface glycoproteins are involved. It is likely that the proteins involved are specific to the trypomastigote stage of the parasite, since only trypomastigotes found in both the insect vector and the vertebrate host bloodstream are capable of invading vertebrate cells. In contrast, the epimastigote stage, found exclusively in the vector, and the amastigote stage, an intracellular stage in the vertebrate host, cannot penetrate the cell directly. We have therefore concentrated our efforts on trypomastigote surface proteins and, along with others, have identified two trypomastigote-specific surface glycoproteins of relative molecular mass (Mr) 90,000 (90K) and 85,000 (85K). Antibody neutralization experiments indicate that the 85K glycoprotein is necessary for efficient interiorization of trypomastigotes in mammalian cells. Here we describe the molecular cloning of a genomic DNA fragment that encodes antigenic determinants present in the 85K trypomastigote surface antigen. The polypeptide fragment encoded by the cloned DNA is recognized by serum from a T. cruzi-infected host and is inferred by DNA sequence analysis to contain a nonapeptide unit that is tandemly repeated five times. Also, the messenger complementary to the cloned DNA fragment is present only in the trypomastigote stage of the parasite.

Antigens, Protozoan↗
PubMedDate not supplied

Smooth muscle cell proliferation in response to endothelial injury in coronary arteries of normal and von Willebrand's disease swine.

The proliferative response of medial smooth muscle cells to balloon-induced endothelial denudation was measured in coronary arteries of normal and von Willebrand's disease swine, a strain of swine with a genetic defect affecting platelet-vessel wall interactions. Animals were sacrificed 48 hours following endothelial injury. Incorporation of a 1-hour pulse label of 3H-thymidine was determined by measuring DNA specific activity. Autoradiography of coronary artery step segments was also performed. The ratio of DNA specific activity in ballooned vessels to that in nonballooned vessels ranged from 1.2 to 26.2. No statistically significant difference in 3H-thymidine incorporation between the two phenotypes was documented (p greater than 0.25). Similarly, DNA incorporation of 3H-thymidine as determined by autoradiography was accelerated to the same degree in ballooned vessels in both phenotypes. The results suggest that von Willebrand factor-mediated platelet activation is not essential for the release of platelet-derived growth factor or that in vivo factors other than platelet-derived growth factor play a significant role in the response of medial smooth muscle cells to acute intimal injury causing endothelial denudation.

Animals↗