108 IS THE BINDING OF COXIELLA BURNETII TO THE ZONA PELLUCIDAE FOLLOWING IN VITRO INFECTION OF IN VITRO-PRODUCED GOAT EMBRYOS CONCENTRATION DEPENDENT?
F. Fieni A , A. Alsaleh A , J. M. de Souza-Fabjan B , P. Mermillod B , E. Corbin B , P. Nascimento B , J. F. Bruyas A and J. L. Pellerin AA LUNAM University, Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, Department of Research into the Health Sanitary and Biotechnology of Reproduction, Nantes, France;
B INRA, UMR7247 Physiologie de la Reproduction et des Comportements, Nouzilly, France
Reproduction, Fertility and Development 29(1) 162-163 https://doi.org/10.1071/RDv29n1Ab108
Published: 2 December 2016
Abstract
Previous experiments using in vitro infection have shown that at concentrations of 109 bacteria/mL, Coxiella burnetii strongly adheres to the zona pellucidae (ZP) of caprine embryos produced in vitro or in vivo (Alsaleh et al., 2013). However, spontaneous infection results in bacterial concentrations of between 106 and 107 bacteria/mL (Rodolakis, 2006; Alsaleh et al., 2011). The aim of this study was to determine whether the concentration of Coxiella burnetii affected its ability to bind to the ZP in vitro. A total of 120 ZP-intact 8- to 16-cell embryos, produced in vitro from ovaries collected at slaughter, were infected with Coxiella burnetti (strain CbC1) produced via ovoculture at 109 mL−1 (3 batches of 10 embryos), 107/mL (5 batches of 10 embryos), 105 mL−1 (3 batches of 8 embryos). After overnight incubation at 37°C in 5% CO2, the embryos were recovered and washed in batches, in 10 successive baths of PBS with 5% FCS, in accordance with International Embryo Technology Society guidelines. The 10 wash baths were collected separately and centrifuged for 1 h at 13,000 × g. The presence of C. burnetii was determined by conventional PCR in each batch of embryos and in the pellets of the 10 wash baths (Table 1). As demonstrated previously, Coxiella DNA was detected in embryo batches after 10 washes when a concentration of 109 bacteria/mL was used for in vitro infection, but this binding property did not occur at lower bacterial concentrations. We can conclude that the attachment of Coxiella burnetii to the zona pellucida of in vitro-produced embryos is concentration dependent. This finding illustrates the limitations of in vitro experiments to study the risk of pathogen transmission via embryo transfer.
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