All known organisms develop and evolve in the presence of gravitational force, and it is evident thatgravity has a significant influence on organism physiology and development. Microgravity is known to affect geneexpression, enzyme activity, cytoskeleton organization, mitotic proliferation and intracellular signaling.Objectives. The aim of the present study was to study some aspects of the development in vitro of mouse embryonictestes in simulated microgravity.Material and Methods. Testes from m

Borrelia burgdorferi sensu stricto is an etiological agent of Lyme disease. The lack of an adequate ex vivosystem for human tissue infection is an obstacle to fully understanding the molecular mechanisms of invasionof tissue by B. burgdorferi and its adaptation within the human host. Here, we report on the development ofsuch a system. We inoculated blocks of human tonsillar tissue with B. burgdorferi spirochetes, cultured themin a low-shear rotating wall vessel (RWV) bioreactor, and analyzed the