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53. Altschul SF, Gish W, Miller W, Myers EW, Lipman DJ: Basic local alignment search tool. J Mol Biol 1990, 215:403–410.PubMedCrossRef Competing interests The authors declare that they have no Selumetinib cost competing interests. Authors’ contributions SZ, CP673451 CR and GW designed the experiments. SZ conducted the experiments including EDX, EDS Mapping, TEM, subcellular fraction, resistance of heavy metals, and tungstate test, analyzed the results and wrote the manuscript. JS performed transposon mutagenesis and Se(IV) resistance. LW, RY, DW and RW conducted SEM, growth and Se(IV) reduction curves. YD assisted to EDS Mapping. CR and GW reviewed and revised

the manuscript. All authors read and approved the final manuscript.”
“Background Streptococcus pneumoniae is a Gram-positive bacterial pathogen that commonly colonizes the human respiratory tract. The ability of S. pneumoniae to generate infections depends on the restrictions imposed by the host’s immunity, in order to prevent its spread

from the nasopharynx to other tissues and sites, such as the middle ear, lungs, blood, and brain [1]. The means by which some strains of S. pneumoniae invade the brain without the occurrence of bacteremia are still unknown. Some authors claim that strains of S. pneumoniae, failing to survive in the bloodstream, can enter the Central Nervous System (CNS) directly from the nasal Bumetanide cavity by axonal transport through the olfactory nerves or trigeminal ganglia [2]. However, from the immunological point of view, glial cells are far more responsive to bacterial infections than are neurons, and therefore more likely to internalize them. This hypothesis is consistent with several recent reports showing that bacteria can infect glial cells from the olfactory bulb and trigeminal ganglia, such as Olfactory Ensheathing Cells (OECs) and Schwann cells (SCs), respectively [3–5]. SCs are glial cells that are closely associated with the peripheral nerves, and can be classified into two types: myelinating and non-myelinating. Myelinating Schwann cells provide the myelin sheath of individual axons, and non-myelinating Schwann cells ensheathe several small axons.