Field Isolates of Mycoplasma ovipneumoniae Exhibit Distinct Cytopathic Effects in Ovine Tracheal Organ Cultures

Abstract

Ovine tracheal ring explants were infected with four different Mjcophsma ovipneumonzae and one M. utginini field isolate and their ability to induce cytopathic effects was tested by measuring ciliary activity and intracellular calmodulin release. Infected tracheal rings showed significantly decreased ciliary activity as compared to the non-infected control rings. There were, however, marked differences between isolates in the onset and severity of the effects which correlated with their ability to produce hydrogen peroxide. Infected tracheal rings released more calmodulin than the non-infected controls. The amount of calmodulin released also varied between isolates, and somewhat reflected the degree of loss of ciliary activity in the corresponding rings induced by the dfferent isolates. Light and electron microscopic examinations of infected tracheal rings revealed disorganisation and sloughing of the epithelium, and association of mycoplasmas only with the cilia. Following repeated in viho passages, the organisms had reduced ability to inhibit ciliary activity which correlated with decreased hydrogen peroxide production. Addition of catalase to the organ cultures delayed loss of ciliary activity. These results suggest that M. ovipneumoniae induced ciliostasis in ovine tracheal ring explants which correlated with hydrogen peroxide production. Furthermore, these M. ovipneumoniae-induced injuries to respiratory epithelial cells could contribute to the role that this organism may play in sheep respiratory disease.

Transmission of Mannheimia Haemolytica From Domestic Sheep (Ovis Aries) to Bighorn Sheep (Ovis Canadensis): Unequivocal Demonstration With Green Fluorescent Protein-Tagged Organisms

“…It is possible that during the lag period, M. ovipneumoniae colonized the upper respiratory tract of at least two bighorn sheep and predisposed them to the tagged M. haemolytica, but whether M. ovipneumoniae played any role in the other two bighorn sheep seems even less certain, based on available data (Table 2). In domestic sheep, M. ovipneumoniae has been shown to render the cilia on the epithelial cells of the upper respiratory tract dysfunctional (Jones et al, 1985;Niang et al, 1998). Previous studies have shown that M. ovipneumoniae does not kill bighorn sheep (Besser et al, 2008) but can predispose them to M. haemolytica infection (Dassanayake et al, 2010).…”

A Metabolic Enzyme as a Primary Virulence Factor ofMycoplasma mycoidessubsp.mycoidesSmall Colony

“…These latter consequently produced less H 2 O 2 in the presence of glycerol compared to the highly virulent African strains. It has been proposed that H 2 O 2 production of certain pathogenic Mycoplasma species causes lysis of erythrocytes, peroxidation of lipids of infected fibroblasts, and inhibition of ciliary movement in infected tracheal organs (34,45). Using catalasedeficient mice, H 2 O 2 production of Mycoplasma pulmonis was suggested as a mycoplasmal virulence factor (15 …”

Capsular Polysaccharide of Mycoplasma ovipneumoniae Induces Sheep Airway Epithelial Cell Apoptosis via ROS‐Dependent JNK/P38 MAPK Pathways

“…Mycoplasma ovipneumoniae (M. ovipneumoniae, MO) has been identified as a pathogenic agent of chronic nonprogressive infection of pneumonia in sheep and goats [1–4]; the nature between a protective and a pathological host response of MO infection currently remains largely unknown. In this regard, the role of capsular polysaccharide (CPS), a major active component for cellular adherence, invasion, immune modulation, and virulence of M. ovipneumoniae remains undefined [5], although several lines of evidences have shown that M. ovipneumoniae is able to produce polysaccharide capsules for facilitating its adherence to ciliated epithelium [3, 6].…”