JOURNAL OF CELLULAR PHYSIOLOGY 143:416-419 (1990)
Mycoplasmas Produce Double-Stranded Ribonuclease PHILIP 1. MARCUS* AND ITSURO YOSHIDA
Department of Molecular and Cell Biology, The University of Connecticut, Storrs, CT 06269-3044 (P.I. M.) and Department of Microbiology, Asahikawa Medical College, Asahikawa, japan (1.Y.) Mycoplasmas (Mollicutesi constitute a constant threat as insidious contaminants of animal cell cultures. They are responsible for myriad biochemical reactions associated with the cells they infect, and undoubtedly have been the source of metabolic and physiological activities attributed to their hosts. In an attempt to demonstrate a dsRNA-inducible double-stranded ribonuclease (dsRNase) in mammalian cells, comparable to that reported in avian cells, we discovered high levels of dsRNase "induced" by a particular stock of vesicular stomatitis virus. We now report that the double-stranded ribonuclease resulted from the activity of a contaminant in that stock-a "noncultivable" Mycoplasma hyorhinis. This report demonstrates the ubiquitous distribution of dsRNase among mycoplasmas, presents some characteristics of the enzyme and its production, and implicates once again mycoplasmas as contaminants of cell culture and potential perturbers of cellular physiology. Double-stranded RNA (dsRNA) and viruses that contain dsRNA or can produce it induce large amounts of dsRNase, along with interferon (IFN) in avian cells (Meegan and Marcus, 1989). Under conditions where virus inducers of IFN stimulate chick embryo cells to produce over 10,000 unitdm1 dsRNase, mammalian cells produce
Mycoplasmas Produce Double-Stranded Ribonuclease PHILIP 1. MARCUS* AND ITSURO YOSHIDA
Department of Molecular and Cell Biology, The University of Connecticut, Storrs, CT 06269-3044 (P.I. M.) and Department of Microbiology, Asahikawa Medical College, Asahikawa, japan (1.Y.) Mycoplasmas (Mollicutesi constitute a constant threat as insidious contaminants of animal cell cultures. They are responsible for myriad biochemical reactions associated with the cells they infect, and undoubtedly have been the source of metabolic and physiological activities attributed to their hosts. In an attempt to demonstrate a dsRNA-inducible double-stranded ribonuclease (dsRNase) in mammalian cells, comparable to that reported in avian cells, we discovered high levels of dsRNase "induced" by a particular stock of vesicular stomatitis virus. We now report that the double-stranded ribonuclease resulted from the activity of a contaminant in that stock-a "noncultivable" Mycoplasma hyorhinis. This report demonstrates the ubiquitous distribution of dsRNase among mycoplasmas, presents some characteristics of the enzyme and its production, and implicates once again mycoplasmas as contaminants of cell culture and potential perturbers of cellular physiology. Double-stranded RNA (dsRNA) and viruses that contain dsRNA or can produce it induce large amounts of dsRNase, along with interferon (IFN) in avian cells (Meegan and Marcus, 1989). Under conditions where virus inducers of IFN stimulate chick embryo cells to produce over 10,000 unitdm1 dsRNase, mammalian cells produce
