BIOL240 Lecture Notes - Lecture 7: Lactobacillales, Facultative Anaerobic Organism, Firmicutes
12 Jul 2017
School
Department
Course
Professor
Document Summary
Both have very thick peptidoglycan cells wall (i. e. gram positive) Firmicutes typically have low gc content (45-60%) Selective pressure and evolutionary time explains the shit of the gc content. Non- sporulating, gram positive firmicutes: staphylococcus and micrococcus. Both catalase positive: can produce the catalase enzyme which is important for eliminating hydrogen peroxide. Both are very resistant to desiccation (dehydration) and are tolerant to very high salt concentration, even tolerating 7. 5% sodium chloride. Pigmentation which helps them withstand dry and oxygen-exposed environment. When grown on plates their colonies display a nice yellow colour. These pigments help eliminate reactive oxygen species (singlet oxygen) Pigmentation interferes with the ability of reactive oxygen species to harm cellular components. Both are found on the surface of the skin. Can distribute through the air associated with dust particles. Viable on surfaces due to their resistant to desiccation and exposure to oxygen. 20% of individuals are carriers of staphylococcus aureus.
