Structure and Function of Bacterial Cells

What's the difference between Gram-negative Bacteria and Gram-positive Bacteria

Cephalosporin Antibiotics: Generations, Uses, Side Effects

The outer membrane is attached to the peptidoglycan sheet by aunique group of lipoprotein molecules.


Inthe Gram-positiveBacteria, the cell wall is thick(15-80nanometers),consisting of several layers of peptidoglycan.

Closely associatedwith the layers of peptidoglycan in Gram-positive bacteria are a groupof molecules called teichoic acids.

All bacterial cells have a cell wall that protects them

Archibald AR, Hancock IC and Harwood CR (1993) Cell wall structure, synthesis, and turnover. In: Sonenshein AL, Hoch JA and Losick R (eds) Bacillus subtilis: And Other Gram‐positive Bacteria: Biochemistry, Physiology, and Molecular Genetics, pp. 381–410. Washington, DC: ASM Press.

FULL TEXT Abstract: LY146032, a cyclic lipopeptide antibiotic, is an inhibitor of cell wall peptidoglycan biosynthesis in gram-positive bacteria

LY146032, a cyclic lipopeptide antibiotic, is an inhibitor of cell wall peptidoglycan biosynthesis in gram-positive bacteria. Although LY146032 at relatively high concentrations inhibited the in vitro polymerization of UDP-linked sugar precursors, inhibition of cell wall formation in intact Staphylococcus aureus and Bacillus megaterium cells did not lead to the accumulation of UDP-N-acetyl-muramyl (MurNAc)-peptide(s). Experiments that measured formation of UDP-MurNAc-peptides revealed that LY146032 inhibited the formation of these nucleotide-linked intermediates. This antibiotic had a disruptive effect on membrane permeability as evidenced by the loss of intracellular potassium immediately after exposure to the drug. The lack of any major disruption of the phosphoenolpyruvate:sugar phosphotransferase system indicated that the membrane is not likely a lethal target for this antibiotic. The findings are consistent with a mechanism by which LY146032 inhibits the formation of precursor molecules utilized in peptidoglycan biosynthesis. The observed membrane effects likely result from transit of the inhibitor to its lethal target site.

The cell wall of Gram negative bacteria is more complex than those of Gram positive bacteria