UMMC micro Test 2 1st

• Bacteria and Eukaryotes: ester-linked straight chain fatty acids
• Archaea: ether-linked branched aliphatic acids
• Bacteria and Archaea have polycistronic mRNA
• Eukaryotes do mRNA splicing, capping, and poly A tail

No cholesterol or sterols except Mycoplasma because they steal sterols from host

• Glycan strands: repeating NAM and NAG, beta 1,4 linkage
• Peptide crosslinks: 5 residue peptide linked to NAM also linked to each other at 3,4 residues
• Use of D-form AA that are not encoded from mRNA, but from enzymes

• 1. Activate NAM & NAG with UDP carrier (UDP-NAM made from UDP-NAG)
• 2. Polymerize stem peptides on UDP-NAM (UDP-NAM-PEP = Park’s nucleotide)
• 3. Load lipid (bactoprenol phosphate) and add UDP-NAG
• 4. Flip across membrane & join existing peptidoglycan
• 5. Crosslink step peptides with transpeptidases

• PBPs (penicillin binding proteins)
• They are the transglycosylase and transpeptidase enzymes
• Most bacteria have at least 4 and they are numbered in order of decreasing MW
• They are targeted by Penicillin (a beta lactam)

• It disrupts the cell membrane by binding to the transglycosylase and transpeptidase enzymes of peptidoglycan synthesis
• It mimics the D-Ala-D-Ala terminus of stem peptides, when bound it is acylated and irreversibly inactivates the enzymes
• Cell wall synthesis slows and degradation continues so the bacteria dies
• Works best on gram +

• They are large antibiotics that can bind the D-ala-D-ala terminus of stem peptides
• This stops transpeptidation (because stem peptides are bound)
• Only works with gram + bacteria, the large molecules can’t cross the outer membrane of gram –

• It is a polymer of ribol or glycerol with linked choline, D amino acids or sugars
• It is negatively charged
• Lipoteichoic acid also has a fatty acid component attached to the cytoplasmic membrane

• The outer leaflet is hydrophilic, but the inner leaflet is hydrophobic (think the inner leaflet is hiding from the water)
• This allows the bacteria to be relatively impermeable to both types of molecules
• Porin channels are used to transport nutrients

• They have a high concentration of lipid material at cell surface (more that 50% is mycolic acids)
• The high concentration of high molecular weight fatty acids (mycolic acid has between 50-90 carbons) allows an acid fast stain to be used to identify them

• Adhesion to host cells with adhesins on the tips of the pili
• Immune escape (alter pili antigenicity)
• Inhibit complement

• If UPEC expresses P-pilus it binds galactose in uroepithelial mucosa in renal tissue (pyelonephritis)
• If UPEC expresses type 1 Pilus, it binds mannose on Uroplakin Ia in bladder (cystitis)

• Eukaryotic flagella (example on sperm) are similar to cilia and whip back and forth
• Bacterial flagella have a rotary motor that can spin both clockwise and counter clockwise, counter-clockwise propels bacteria forwards, clockwise causes it to tumble

One flagellum at a pole

one tuft of flagella at pole

flagella at both poles

flagella all around the cell

Clostridium and Bacillus

• Exosporum – membrane
• Coat(s) – keratin-like protein with S-S bonds
• Cortex – concentric rings of peptidoglycan
• Inner membrane – similar to cytoplasmic membrane
• Core – contains DNA and enzymes (no mRNA) also contains dipicolinic acid (DPA) which crosslinks with spore proteins for heat / radiation protection

It competitively inhibits enzymes in the cytoplasm responsible for assembling the D-ala-D-ala dipeptide prior to its incorporation into peptidoglycan

The fatty acids of lipid A