Hemolytic and Hemoxidative Activities inMycoplasma penetrans

Abstract

Mycoplasma penetrans is a newly isolated Mollicute from the urine of patients infected with human immunodeficiency virus that demonstrates the capacity to adhere to and invade human cells. A previous report, based on assays with mouse red blood cells (RBCs), indicated that M. penetrans lacked hemolytic activity. In our studies, we incubated different isolates of M. penetrans with various RBC species and observed hemolytic zones surrounding individual mycoplasma colonies. All M. penetrans strains displayed hemolysis after 2 to 3 days of incubation. Hemolytic activity diffused from single colonies, eventually causing complete lysis. Hemolysis was most pronounced with sheep RBCs, followed by horse, chicken, and human cells. Furthermore, hemolytic activity was demonstrable in both intact mycoplasma cell preparations and spent culture supernatant. However, unlike intact mycoplasmas, the hemolytic activity in the supernatant was dependent on the reducing agent, cysteine. In addition to hemolysis, a brown precipitate was closely associated with mycoplasma colonies, suggesting oxidation of hemoglobin. Absorption spectra indicated that hemoglobin was oxidized to methemoglobin, and the addition of catalase demonstrated H 2 O 2 -mediated hemoxidation. Other experiments suggested that hemoxidation enhanced total hemolysis, providing the first evidence of both hemolytic and hemoxidative activities in M. penetrans.Mycoplasmas, members of the cell wall-less Mollicutes and considered among the smallest self-replicating cells, have been detected in a wide range of hosts, including humans, other vertebrates, invertebrates, and plants (2,19,20,27). In previous studies of pathogenic mycoplasmas, hemadsorption and cytadherence activities were closely associated with virulence potential (2, 30). For example, hydrogen peroxide-mediated and membrane-associated hemolytic activities have been found in numerous Mycoplasma species (15,24,30), and analysis of mycoplasma genomic sequences revealed the presence of a hemolysin-like gene (VXpSPT7_orf424) in Mycoplasma pneumoniae (13) and a homologous gene (MG146) in Mycoplasma genitalium (10). It is well known that bacterial hemolysins lyse erythrocytes (RBCs) and a variety of other cell types, including mast cells, neutrophils, and polymorphonuclear cells, which enables hemolytic microorganisms to directly damage host tissues as well as induce inflammatory responses (5). However, a new species, Mycoplasma penetrans, which was isolated from the urine of patients infected with human immunodeficiency virus (22), was shown to actively invade mammalian cells in culture (21) and cause cytopathology in experimentally infected chicken embryos (12) but lack hemolytic activity (24). In this report we describe hemolytic activity in all isolates of M. penetrans and show that H 2 O 2 -mediated hemoxidative activity contributes to total mycoplasma-mediated hemolysis. MATERIALS AND METHODSBacterial strains and medium. M. penetrans cells (GTU-54 and isolates from France and Texas) (11) were obtained from J. T...

Characterization of a Unique ADP-Ribosyltransferase of Mycoplasma penetrans

“…RNA, in the absence of reverse transcriptase, served as an internal control at all time points. Similar transcriptional patterns of MYPE9110 were observed for two other clinical strains of M. penetrans that were isolated in Texas and France (data not shown) (18).…”

“…Manipulation of the cytoskeletal network by bacterial toxins, including ADP-ribosylating toxins, was previously reported for both gram-negative and gram-positive bacteria (26). Until recently, the only genome-encoded potential virulence factors of M. penetrans included endonucleases, hemolysins, and proteases (3,18,32), and their roles in pathogenesis remain unclear.…”

Cardiolipin Synthetase Is Involved in Antagonistic Interaction (Reverse CAMP Phenomenon) of Mycoplasma Species with Staphylococcus aureus Beta-Hemolysis

“…The blood samples were washed twice in phosphate-buffered saline (PBS) and diluted to a final concentration of 2% packed cells. Hemolytic activity was determined as described before (4). In brief, 50 g protein of intact M. hyorhinis cells, purified membranes or the cytosolic fraction, were incubated with 2% packed RBCs in a total volume of 1 ml (to be referred to as the test mixture), in the presence or absence of 2 to 4 mM cysteine (Merck) for 18 h at 37°C in a rotator shaker (30 rpm).…”

“…Most mycoplasmas are parasites and depend on host adhesion for infection (2,3). Numerous pathogenic Mycoplasma species possess hemadsorption and cytadherence activities, such as hydrogen peroxide-mediated and membrane-associated hemolytic activities, which are associated with virulence potential (4,5). Bacterial hemolysins can lyse red blood cells (RBCs) and a variety of other cell types, such as mast cells, neutrophils, and polymorphonuclear cells (6).…”

Identification of a site-specific tyrosine recombinase that mediates promoter inversions of phase-variable mpl lipoprotein genes in Mycoplasma penetrans

“…Although the pathogenicity of M. penetrans to humans remains questionable, the characteristics of this bacterium (i.e. invasion of eukaryotic cells, toxicity to chick embryo, and haemolytic and haemoxidative activity) (Giró n et al, 1996;Kannan & Baseman, 2000;Lo et al, 1993) suggest its potential pathogenicity to humans. M. penetrans also has the ability to change its surface antigenicity frequently by changing the expression pattern of the P35 family lipoproteins Röske et al, 2001).…”