Reduction of Hydrogen Peroxide Accumulation and Toxicity by a Catalase from Mycoplasma iowae

Abstract

Mycoplasma iowae is a well-established avian pathogen that can infect and damage many sites throughout the body. One potential mediator of cellular damage by mycoplasmas is the production of H2O2 via a glycerol catabolic pathway whose genes are widespread amongst many mycoplasma species. Previous sequencing of M. iowae serovar I strain 695 revealed the presence of not only genes for H2O2 production through glycerol catabolism but also the first documented mycoplasma gene for catalase, which degrades H2O2. To test the activity of M. iowae catalase in degrading H2O2, we studied catalase activity and H2O2 accumulation by both M. iowae serovar K strain DK-CPA, whose genome we sequenced, and strains of the H2O2-producing species Mycoplasma gallisepticum engineered to produce M. iowae catalase by transformation with the M. iowae putative catalase gene, katE. H2O2-mediated virulence by M. iowae serovar K and catalase-producing M. gallisepticum transformants were also analyzed using a Caenorhabditis elegans toxicity assay, which has never previously been used in conjunction with mycoplasmas. We found that M. iowae katE encodes an active catalase that, when expressed in M. gallisepticum, reduces both the amount of H2O2 produced and the amount of damage to C. elegans in the presence of glycerol. Therefore, the correlation between the presence of glycerol catabolism genes and the use of H2O2 as a virulence factor by mycoplasmas might not be absolute.

Genomic Characterization of a Novel Gut Symbiont From the Hadal Snailfish

“…in riboflavin synthase of CML. Instead, virulence factors were absent in the CML, but common to other pathogens (Glass et al, 2000;Kannan and Baseman, 2006;Szczepanek et al, 2010;Indikova et al, 2013;Kokkayil and Dhawan, 2015) and genes involved in the generation of H 2 O 2 , which is a major mediator for Mycoplasma pathogens to cause cellular damage (Pritchard et al, 2014), were also absent in the CML. All these results indicated that "Ca.…”

Mycoplasma pneumoniae from the Respiratory Tract and Beyond

“…The activities of enzymes of M. genitalium that control the damage done by reactive oxygen species, such as peptide methionine sulfoxide reductase (166), organic hydroperoxide reductase (167), and hydroperoxide peroxidase (168), have been described. However, direct reduction of hydrogen peroxide by catalase among mycoplasmas is described only in Mycoplasma iowae (169). The fact that M. gallisepticum engineered to produce catalase is strongly attenuated for toxicity in the invertebrate animal model Caenorhabditis elegans (169, 170) not only underscores the pathogenic value of reactive oxygen species but also might explain the absence of catalase in M. pneumoniae.…”

The Variable Internal Structure of the Mycoplasma penetrans Attachment Organelle Revealed by Biochemical and Microscopic Analyses: Implications for Attachment Organelle Mechanism and Evolution

“…MYPE1530, MYPE1550, MYPE1560, and MYPE1570. Together with MYPE4000, they shared no specific sequence homology with other proteins except in a close relative of M. penetrans, namely, Mycoplasma iowae (25); however, the first four were labeled as predicted cytoskeletal proteins in the original annotation of the M. penetrans genome, on the basis of predicted extensive ␣-helical coiled-coil structures, reminiscent of Mycoplasma pneumoniae AO protein HMW2 (14), which is predicted to constitute a major structural element within the M. pneumoniae AO cytoskeleton (26)(27)(28). The absence of sequence homology of these five proteins to the proteins of the AO cytoskeleton of M. pneumoniae (28) or the analogous structure in M. mobile (29), together with the disparity in the detergent-insoluble structures between M. penetrans and mycoplasmas from other phylogenetic clusters, is consistent with a model in which attachment organelles arose independently multiple times during the course of mycoplasma evolution (7,30).…”