CAS-02-502A_GROUP 2 - Cell Walls of Bacteria and Archaea.pdf

CELL WALLS OF BACTERIA AND ARCHAEA GROUP 2 - CAS-02-502A  REPORTERS BONDOY, Gwenneth L. CARO, Lance Edgard D. DELOS SANTOS, Gemmalyn Joy P. MALIG, Daniela S. MARFA, Lucille Zhen G. MENDOZA, Charlene Dianne S. OGATIS, Marry Rose B.  Peptidoglycan Chemistry o...

CELL WALLS OF BACTERIA AND ARCHAEA GROUP 2 - CAS-02-502A  REPORTERS BONDOY, Gwenneth L. CARO, Lance Edgard D. DELOS SANTOS, Gemmalyn Joy P. MALIG, Daniela S. MARFA, Lucille Zhen G. MENDOZA, Charlene Dianne S. OGATIS, Marry Rose B.  Peptidoglycan Chemistry of Peptidoglycan | The Gram- Positive Cell Wall  Chemistry of Peptidoglycan PEPTIDOGLYCAN STRUCTURE: - Consists of a glycan chain of alternating N- acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) residues. ROLE IN BACTERIAL CELLS: - Provides rigidity and shape to the cell. DIFFERENCES IN GRAM-POSITIVE AND GRAM-NEGATIVE BACTERIA ANTIBIOTIC TARGET  The differences between Gram-positive and Gram-negative bacteria, focusing on their cell walls:  Structure of the Peptidoglycan Layer Basic Structure of Peptidoglycan THE GRAM-POSITIVE CELL WALL Gram-positive cell walls are known for their thick and multi-layered peptidoglycan compared to gram-negative ones. Aside from the peptidoglycan, acidic molecules called teichoic acid are also embedded in the cell walls of gram-positive bacteria. Aside from the peptidoglycan, acidic molecules called teichoic acid are also embedded in the cell walls of gram-positive bacteria. Some bacteria and archaea lack cell walls but survive due to tough membranes or living in protective environments. - Mycoplasmas: sterols - Thermoplasma: lipoglycans  The Outer Membrane Chemistry and Activity of LPS | The Periplasm and Porins | Relationship of Cell Wall Structure to the Gram Stain Chemistry and Activity of LPS Lipopolysaccharide or LPS a combination of lipid with polysaccharide and protein that forms the major portion of the outer membrane in gram-negative bacteria. The LPS consists of two components: core polysaccharide and O-specific polysaccharide. Lipid A: A fatty acid that connects through the amine groups and embeds in the bacterial outer membrane. Core Polysaccharide: consists of a short chain, which connects the Lipid A anchor to O-antigen. O-specific Polysaccharide: or O-antigen that is attached to the core polysaccharide and extends from the core out into the environment. The Periplasm and Porins  The Periplasm and Porins A. Periplasm The periplasm is the space between the inner (cytoplasmic) membrane and the outer membrane in Gram-negative bacteria. Gel-like matrix filled with various enzymes, proteins, and other molecules. Maintains osmotic balance.  The Periplasm and Porins B. Porins Porins are specialized proteins located in the outer membrane of Gram-negative bacteria. Form channels that allow the passage of small molecules, ions, and nutrients into the periplasm. 2 types of porins: specific and nonspecific  The Periplasm and Porins C. Relationship between periplasm and porins Porins enable the entry of nutrients, while the periplasm manages those nutrients once inside.  Relationship of Cell Wall Structure to the Gram Stain Gram staining is a laboratory test to identify what kind of bacteria are present in. gram-negative gram-positive Chemical used in Gram staining crystal violet, the primary stain iodine, alcohol for decolorization safranin as a counterstain TheIR Relationship The thickness and Structure of the Bacterial Cell Wall + Gram Stain = Gram-positive or Gram-negative Bacteria Gram-positive bacteria: Have a thick layer of peptidoglycan in their cell walls. Retains the crystal violet dye. Appeared purple. Resist decolorization by alcohol or acetone. Gram-negative bacteria: Have a much thinner layer of peptidoglycan. The crystal violet dye is easily washed away by alcohol or acetone. Take up the counterstain (safranin), making them appear pink or red after the Gram stain. Thicker peptidoglycan layer, retains initial dye (crystal violet) = Gram- positive bacteria. Thinner peptidoglycan layer, wash away the initial dye (crystal violet) = Gram-negative bacteria. ARCHAEAL CELL WALLS Pseudomurein and Other Polysaccharide Walls | S-Layers  Pseudomurein and Other Polysaccharide Walls STRUCTURAL COMPONENTS N-acetylglucosamine (GlcNAc), this sugar molecule is also existing in peptidoglycan & N-acetyltalosaminuronic (TalaNAcA), and it replaces the N-acetylmuramic acid (MurNAc) found in bacterial peptidoglycan  GLYCOSDIDIC BOND The glycan strands (GlcNAc & TalaNAcA) are cross- linked by peptide subunits. The glycosidic bonds in pseudomurein is β (1→3) while the bonds in peptidoglycan has β (1→4) as its glycosidic linkages with all the amino acids being levo-rotatory stereoisomer. Pseudomurein and Other Polysaccharide Walls Structure of Pseudomurein Overall, peptidoglycan and pseudomurein emerged by convergent evolution right after the diverged of Bacteria and Archaea, leaving them with different ancestors. Not all Archaea have pseudomurien since some other cell walls contain polysaccharides composed of glycoproteins & proteins.  S-LAYERS Archaea's most common type of cell wall is the paracrystalline surface layer, or S-layer consisting of interlocking molecules of protein or glycoprotein. S-layers are sufficiently strong to withstand osmotic pressures without any other wall components. For instance, Methanocaldococcus jannaschii consist only of an S-layer.  S-Layers S-layer is always the outermost wall layer with direct contact with the environment that functions as a selective sieve and retain proteins near the cell surface. REFERENCES: 2024). App.goo.gl. https://images.app.goo.gl/8E6wjG5o2BMmyzmJ7 (2024). Fineartamerica.com. https://images.fineartamerica.com/images-medium-large-5/1-sucrose-specific-porin-molecule- science-photo-library.jpg ‌ ount Sinai Health Library. (n.d.). Gram stain. Mount Sinai Health System. M https://www.mountsinai.org/health-library/tests/gram-stain (n.d.) Figure 1. Representative structure of the molecular components of. ResearchGate. https://www.researchgate.net/figure/Representative-structure-of-the-molecular-components-of-smooth-LPS-The- hypervariable_fig1_318397406 (n.d.). Microbial Cell Structure and Function [Review of Microbial Cell Structure and Function]. In Brock Biology of Microorganisms. Outer Membrane Porins | SpringerLink. (2024). Outer Membrane Porins | SpringerLink. Www.google.com. https://images.app.goo.gl/FQ4Qje96VBNsSGTP7 Thank you!