Secreted sialidase activity of canine mycoplasmas

Abstract

Through a survey of the phylogenetic distribution of sialidase among mycoplasmas, we detected activity secreted by the type strains of three of eleven species frequently or first isolated from dogs. The specific activity of washed cells of the type strains of Mycoplasma canis, Mycoplasma cynos, and Mycoplasma molare ranged from 5.2 ± 0.8 × 10 -6 to 1.1 ± 0.3 × 10 -5 enzymatic units per colonyforming unit (U/CFU). Cells of M. molare strain H542 T had twice the specific activity (P < 0.05) of M. canis strain PG14 T or M. cynos strain H831 T . Significant differences in sialidase activity existed among nine clinical isolates of M. canis, ranging from not detectable to 2.1 ± 0.1 × 10 -5 U/CFU. The type strains of other species previously isolated from dogs (Mycoplasma arginini, Mycoplasma bovigenitalium, Mycoplasma edwardii, Mycoplasma felis, Mycoplasma gatae, Mycoplasma maculosum, Mycoplasma opalescens, and Mycoplasma spumans) did not exhibit either secreted or cell-associated sialidase activity. Neither specific nor degenerate PCR primers complementary to the three known mycoplasmal sialidase alleles were able to amplify orthologs in M. canis, M. cynos, or M. molare, further evidence that the secreted sialidase of those species is distinct from the strictly cell-associated sialidases of Mycoplasma alligatoris, Mycoplasma synoviae, and Mycoplasma gallisepticum. This is the first report of a well-known bacterial virulence factor whose expression varies among strains of certain Mycoplasma species that infect dogs.

New and Emerging Pathogens in Canine Infectious Respiratory Disease

“…24 It is a known virulence factor in other bacteria, including some mycoplasma (M. alligatoris, M. synoviae, and M. gallisepticum). 8,12,70,72 The enzyme can exert a direct toxic effect on the host cells as well as interfere with host defense mechanisms. 24 The sialidase enzyme catalyzes hydrolysis of a-(2-3)-, a-(2-6)-, and a-(2-8)-glycosidic linkages of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid, and synthetic substrates.…”

Identification of differentially expressed miRNAs through high-throughput sequencing in the chicken lung in response to Mycoplasma gallisepticum HS

“…Mycoplasmosis occurs frequently in humans and animals around the world and is caused by Mycoplasmas, which is primarily known as an extracellular pathogen (Atkinson et al, 2008;Chazel et al, 2010;Gambarini et al, 2009;May and Brown, 2009;McVey, 2010;Osman et al, 2009;Sykes, 2010). Mycoplasma gallisepticum (MG), the most important avian pathogenic mycoplasma, causes avian chronic respiratory disease (CRD), especially in chickens and turkeys, which features inflammation of the trachea, air sacs and lungs (Ley, 2003;Stipkovits et al, 2012;Yoder, 1991).…”

Cellular Microbiology of Mycoplasma canis

“…2C) supports the conclusion that the enzyme adheres predominantly to ␣-(2,6)-linked sialoreceptors. The proportional expression of this glycosylation pattern at different anatomical sites, as well as strain differences in the amounts of sialidase secreted (12), could influence host species range, primary colonization of respiratory or urogenital tract mucosal surfaces, and dissemination and secondary localization of M. canis cells in an infected host. The presence of visible M. canis inside nonphagocytic cells and its recovery following eradication of extracellular bacteria from both nonphagocytic and phagocytic cells demonstrated its innate capacity for intracellular invasion and persistence (Fig.…”

“…Most strains of M. canis secrete a form of sialidase (neuraminidase) encoded by the nanI gene that might modulate cytadherence, transmission, and possibly host cell injury (12). MDCK cells display terminal sialic acid with both ␣-(2,3) and ␣-(2,6) linkages to subterminal galactose in cell surface antennary oligosaccharides (21,22), but the surface glycosylation patterns of DH82 histiocytes and C8-D1A type I astrocytes are not well documented.…”

“…Atypical M. canis strain LV lacks any detectable sialidase activity (12). For the present studies, the genetic basis of its sialidase-negative phenotype was determined by whole-genome sequencing.…”