Bacterial cell wall synthesis

cell wall synthesis and its importance

1. BACTERIAL CELL WALL SYNTHESIS PRESENTED BY, D.IRENE 16PGZ001 M.Sc.Zoology ( spl in Biotechnology) Lady Doak College, Madurai.

2. contents Structure of peptidoglycan Synthesis of peptidoglycan Role of cytoskeleton in cell wall synthesis Patterns of cell wall synthesis Significance of peptidoglycan cell wall

3. PEPTIDOGLYCAN CELL WALL

4. Ultra structure of cell wall Gram positive bacterial cell wall Gram negative bacterial cell wall

5. Structure of peptidoglycan

6. Synthesis of peptidoglycan SYNTHESIS OF UDP-NAG Fructose-6-phosphate glucosamine-1-phosphate N-Acetylglucosamine-1-phosphate UDP-NAG Acetyl-coA CoA

7. SYNTHESIS OF UDP-NAM UDP-NAG UDP-NAM UDP-NAM Penta peptide PEP Pi NADPH NADP+ Amino acids are added one at a time sequentially.

8. Peptidoglycan cell wall synthesis

9. Bactoprenol unit Pyrophosphate unit

10. transpeptidation Peptidoglycan Cross-Links . (a) E. coli peptidoglycan with direct cross-linking, typical of many gram negative bacteria. (b ) Staphylococcus aureus peptidoglycan. S.aureus is a gram-positive bacterium. NAM is N- acetylmuramic acid. NAG is N- acetylglucosamine . Gly is glycine. Although the polysaccharide chains are drawn opposite each other for the sake of clarity, two chains lying side-by-side may be linked together

11. Role of cytoskeleton in cell wall synthesis Cytoskeletal structures formed by MreBCD proteins control cell shape by controlling the cell wall synthesis. Any mutations that lead to the defects in bacterial cell shape are directly associated with a defect in cell wall synthesis. Multiple mutations in pbp genes can convert rod shaped E.coli and B.subtilis into round or branched cells.(Nelson et al .,2000) Similarly mutation in TagF (enzyme involved in teichoic acid synthesis) converts B.subtilis to round cells. ( Henriques et al., 1998)

12. <a href ="https://www.researchgate.net/figure/225086120_fig2_Figure-2-MreB-and-Mbl-mutants-present-specific-morphological-defects-Here-are-presented"><img src ="https://www.researchgate.net/profile/Arnaud_Chastanet/publication/225086120/figure/fig2/AS:302571546791942@1449150086790/Figure-2-MreB-and-Mbl-mutants-present-specific-morphological-defects-Here-are-presented.png" MreB and Mbl mutants present specific morphological defects ( Chastanet and Carballido 2012)

13. PATTERNS OF CELL WALL SYNTHESIS Wall Synthesis Patterns. Patterns of new cell wall synthesis in growing and dividing bacteria. Streptococci and some other gram-positive cocci. Synthesis in rod-shaped bacteria (E. coli, Salmonella, Bacillus). The zones of growth are in turquoise. The actual situation is more complex than indicated because cells can begin to divide again before the first division is completed

14. Significance of peptidoglycan Osmotic lysis

15. conclusion Peptidoglycan wall is crucial for the bacterial growth, protection and maintenance of the cell shape. Cytoskeletons play a crucial role in cell shape determination but the specific effectors of cell wall receptors of cell wall morphogenesis controlled by cytoskeleton is unknown ( Scheffers and Pinho , 2005) All the factors, responsible for the cell wall synthesis, if studied it would be effective in designing drugs and antibiotics.

16. THANK YOU!

17. References Henriques , A. O., P. Glaser, P. J. Piggot , and C. P. Moran, Jr. 1998. Control of cell shape and elongation by the rodA gene in Bacillus subtilis . Mol.Microbiol . 28:235–247. Honeyman , A. L., and G. C. Stewart. 1989. The nucleotide sequence of the rodC operon of Bacillus subtilis . Mol. Microbiol . 3:1257–1268. Nelson, D. E., and K. D. Young. 2000. Penicillin binding protein 5 affects cell diameter, contour, and morphology of Escherichia coli . J. Bacteriol.182:1714–1721. Arnaud Chastanet and Rut Carballido ., The actin-like MreB proteins in Bacillus subtilis: A new turn., Article in Frontiers in bioscience (Scholar edition) · June 2012 DOI: 10.2741/S354 · Source: PubMed. Dirk-Jan Scheffers and Mariana G. Pinho ., Bacterial Cell Wall Synthesis: New Insights from Localization Studies., microbiology and molecular biology reviews, Dec. 2005, p. 585–607 Vol. 69, No. 4 1092-2172/05/$08.000 doi:10.1128/MMBR.69.4.585–607.2005 Prescott,Harley and Kleins , Microbiology., 7 edition., McGraw Hill publications.,New York.,2008.,pg-55,232,234,841.