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Increased sister chromatid exchange in human lymphocyte cultures infected with mycoplasma
Abstract:
The effects of fermenting, poorly arginine-utilizing Mycoplasma fermentans and arginine-utilizing Mycoplasma salivarium on the frequency of sister chromatid exchange (SCE) in cultured human lymphocytes were examined. M. fermentans caused no apparent mitosis inhibition of lymphocytes and the increase in SCE frequency was dependent on the inoculum size of the mycoplasma. An evident increase in SCE frequency was observed in lymphocytes infected with smaller inoculum sizes of M. salivarium whereas there was mitosis inhibition of lymphocytes infected with larger inoculum sizes of the mycoplasma. In lymphocyte cultures infected with M. salivarium, the addition of arginine to the culture medium reduced mitosis inhibition but did not diminish the increase in SCE frequency, indicating that arginine depletion was not involved in causing the induction of SCEs in mycoplasma-infected lymphocytes. With regard to the genetic effectiveness of SCE, these results suggested that mycoplasmas are capable of inducing cytogenetic changes in infected host cells.
Insights
Mycoplasma bacteria can induce genetic changes in human cells. Certain species, like Mycoplasma salivarium, increase sister chromatid exchange (SCE) frequency, a marker of genetic damage, in lymphocytes.
Area of Science:
- Microbiology
- Genetics
- Cell Biology
Background:
- Mycoplasma species are known to interact with host cells.
- The impact of Mycoplasma infection on host cell genetics, specifically sister chromatid exchange (SCE), is not fully understood.
Purpose of the Study:
- To investigate the effects of Mycoplasma fermentans and Mycoplasma salivarium on SCE frequency in human lymphocytes.
- To determine if arginine metabolism by Mycoplasma influences SCE induction.
Main Methods:
- Cultured human lymphocytes were exposed to varying inoculum sizes of M. fermentans and M. salivarium.
- Mitosis inhibition and SCE frequency were analyzed in infected lymphocytes.
- Arginine was added to cultures infected with M. salivarium to assess its role.
Main Results:
- M. fermentans did not inhibit lymphocyte mitosis but increased SCE frequency in a dose-dependent manner.
- M. salivarium increased SCE frequency at lower doses and inhibited mitosis at higher doses.
- Arginine supplementation reduced M. salivarium-induced mitosis inhibition but did not affect SCE induction.
Conclusions:
- Mycoplasmas, including M. fermentans and M. salivarium, can induce cytogenetic changes, specifically increasing SCE frequency in host lymphocytes.
- Arginine depletion is not the mechanism by which M. salivarium induces SCEs.