Ameloblast showing a disruption in enamel production when the person is born. High fevers in childhood are also an example of bodily stressors causing interruptions in enamel production. Another possible example of this sensitivity (stress response pathway activation) may be the development of dental fluorosis after childhood exposure (between the ages of 2 to 8 years old) to excess fluoride, an elemental agent used to increase enamel hardness and prevent dental caries. Ameloblast Ameloblasts are cells present only during tooth development that deposit tooth enamel, which is the hard outermost layer of the tooth forming the surface of the crown. Each
S-layer pores with 2–8 nm in diameter. The terminology “S-layer” was used the first time in 1976. The general use was accepted at the "First International Workshop on Crystalline Bacterial Cell Surface Layers, Vienna (Austria)" in 1984, and in the year 1987 S-layers were defined at the European Molecular Biology Organization Workshop on “Crystalline Bacterial Cell Surface Layers”, Vienna as “Two-dimensional arrays of proteinaceous subunits forming surface layers on prokaryotic cells” (see "Preface", page VI in Sleytr "et al. 1988"). For a brief summary on the history of S-layer research see references For many bacteria, the S-layer represents the outermost interaction