Adenosine phosphorylase activity in a mutant HEp-2 cell line contaminated with Mycoplasm hyorhinis

Established cell lines from different groups of vertebrates undergo metabolic cooperation with one another

The prelabeled-donor technique was used to study metabolic cooperation in the established cell lines, RTG-2, FHM, and IgH-2, which are respectively from rainbow trout, fathead minnow, and green iguana. The donors were grown with [3H]hypoxanthine for 3 h after which the radioactive medium was removed and the recipients, marked by the presence of latex beads, were added. Cells from each of these lines were capable of cooperating with themselves and with one another because after 5.5 h the recipients in contact with donors were more significantly labeled than those that were not in contact. Cells FHM and IgH-2 were grown with HGPRT-Chinese hamster fibroblasts, CHW-1102, in the presence of [3H]hypoxanthine. In all cases the CHW-1102 cells that were in contact with the nonmammalian cells were more heavily labeled than those that were not in contact. Thus cells from a fish and a reptile undergo metabolic cooperation with cells from a mammal.

Analysis of multiple isoenzyme expression among twenty-two species of Mycoplasma and Acholeplasma

Crude extracts of triple-cloned, purified cultures of 22 species of Mycoplasma and Acholeplasma were examined for expression of 21 isozyme systems routinely used to type mammalian cells. Nine previously described enzymes (purine nucleoside phosphorylase, adenylate kinase, dipeptidase, esterase, glyceraldehyde-3-phosphate dehydrogenase, glucose phosphate isomerase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and superoxide dismutase) and three enzymes not previously reported in mycoplasma (triose phosphate isomerase, inorganic pyrophosphatase, and acid phosphatase) were detected in some or all of the species examined. These findings provide new information on the enzymatic expressions of these organisms. Three of the isozyme systems (superoxide dismutase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase) were present in Acholeplasma species but not in any Mycoplasma species. The characteristic pattern of electrophoretic mobility of the 12 isozyme systems also provides a useful biochemical property for identification, characterization, and classification of these mycoplasmas. Mycoplasma isozyme expression for seven of the enzymes were readily detected in various infected-cell culture lines by using either cell extracts or concentrated cell culture fluids. Mycoplasma-specific enzymes found in infected-cell extracts had the same electrophoretic mobility patterns as enzymes obtained from broth-grown mycoplasmas of the same species. Expression of homologous mammalian enzymes was not detectably altered by infection with mycoplasmas.

Simulation and prevention of retrovirus--specific reactions by mycoplasmas

From human mycosis fungoides tumor-derived cell lines, Mycoplasma hyorhinis was isolated. This mycoplasma shared the following characteristics with retroviruses: uptake of 3H-uridine, but not of 3H-thymidine in cell culture; banding at 1.16 g/ml sucrose density and partial shift to retrovirus core density position (approximately equal to 1.24 g/ml) after detergent treatment; incorporation of 3H-TMP into high molecular weight material in standard reverse transcriptase assays with the template-primer poly (A) . (dT)12. On the other hand, the specific reverse transcriptase reaction of retroviruses with poly(A) . (dT)12 and poly(C) . (dG) approximately 16 was almost completely abolished in the presence of the mycoplasma. Thus, M. hyorhinis may interfere with identification and isolation procedures for retroviruses.