11/17/2023 0 Comments Spherical bacteriaAlternatively, increase of the surface area could be driven by hydrolysis of peptidoglycan bonds catalysed by specific autolysins. Reshaping of the flat septum, resulting in doubling of the external surface area of peptidoglycan, could theoretically occur in the absence of synthesis, if accompanied by changes in the angle of the glycan chains with respect to the peptide chains 6. aureus, increase of the cell surface area required for growth has been attributed to a process of reshaping the flat septum into curved hemispheres of the two daughter cells, which occurs immediately after splitting of the mother cell during division 2. Given that an elongation-specific machinery seems to be absent in S. PBPs are enzymes involved in the last steps of peptidoglycan biosynthesis, which catalyse the polymerization of the glycan strands, as well as their crosslinking via peptide stems. subtilis have 12 and 16 PBPs, respectively, which localize at the septum or at the lateral wall 4. aureus has only four native Penicillin-Binding Proteins (PBPs 1–4), described to localize at the septum, while E. aureus has been proposed to have only one cell wall synthesis machine, which incorporates peptidoglycan mostly at the division septum 4, 5, while rod-shaped bacteria such as Escherichia coli or Bacillus subtilis have two major cell wall synthesis machines, one for incorporation of new peptidoglycan at the division septum and another for elongation of the lateral wall 4. Orientation of division planes is merely one of the distinctive features of the staphylococcal cell cycle. Peptidoglycan, the major component of the bacterial cell wall, has been proposed to encode epigenetic information in the form of protuberant, ring-like structures that mark previous division planes and are used by Staphylococcus aureus to divide accurately in sequential perpendicular planes 3. Given that this spatial information varies with each division, it cannot be encoded by DNA 3. Division in three planes implies that cells retain information about the positioning of the two preceding divisions to divide with precision. This mode of division is less common in bacterial cells than equatorial division, observed in many genera. S taphylococci are spherical organisms that divide sequentially in three orthogonal planes over three consecutive division cycles 1, 2.
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