Term
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Definition
-Crystal violet (primary stain)
-Gram's iodine (mordant; sets stain)
-Ethyl alcohol (decolorization)
-Safranin (counterstain) |
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Term
| What is and is not in the cytoplasmic membrane? |
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Definition
-It is actually more protein (70%) than phospholipid (30%)
-It contains no sterols; except for **mycoplasma species which lack a cell wall
-Mycoplasma pneumonia causes walking pneumonia |
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Term
| What are the two types of glcocalyces? |
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Definition
-Glycocalyx is a general term for "sugar-coat"
-When it is tight and distinct we call it a **capsule
-When it is irregular and diffuse we call it a **slime layer |
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Term
| What test do we use that relies on the presence of a capsule? |
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Definition
-The Quellung reaction
-Involves antibodies that bind to, and change the appearance of the capsule; enlarges and becomes clear |
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Term
| What is the name for capsular antigens? |
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Definition
-K antigens (think KaKaKaKapsular)
-Can be used in some vaccines like for S. pneumoniae and N. meningitidis |
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Term
| What are the different types of pili? What is another name for pili? What is the protein type? |
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Definition
-Pili; aka fimbriae
-Can be *F pili; sex pili for conjugation (think, fucking-pili)
-Common pili are for cell adherence
-Can be used in virulence; N. gonorrhoeae
-Composed of pilin (pilE) |
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Term
| What are flagella antigens called? What do they use for energy? What are the different arrangements for flagella? |
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Definition
-H antigens (think Hairy)
-They use the proton motive force directly for energy (and why wouldn't they since the proton pumps are directly in the pm for bac.)
Arrangements;
-Monotrichous; one only
-Lophotrichous; multiple, all together
-Amphitrichous; two, one at each end
-Peritrichous; bunch all over |
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Term
| What is the flagellar attachment structure in gram-? |
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Definition
-L,P,S,M rings in the outer membrane, pep layer, periplasmic space, and cytoplasmic membrane, respectively
-L for last
-P for pep layer
-S for space
-M for membrane |
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Term
| What are the ribosomal subunits and important subsubunits? |
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Definition
-70S is the whole
-30S subunit (16S + proteins)
-50S subunit (23S + 5S + proteins) |
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Term
| What do we see in a high concentration in spores? What gram type can make them? |
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Definition
-Calcium dipicolinic acid
-Only gram+ can make them (not all g+) |
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Term
| What are the layers of a spore? |
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Definition
| -Core, pm, wall (normal), cortex (special pep), keratin coat, exosporium (protein lipid membrane) |
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Term
| What are the two subunits composing peptidoglycan? |
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Definition
-NAG; N-acetylglucosamine (aka GluNAc)
-NAM; N-acetylmuramic acid (aka MurNAc)
-Both are amino-sugars
-A pentapeptide is attached to MurNAc to complete the peptidoglycan monomer (one a.a. chopped off later) |
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Term
| What is the pentapeptide chain for gram+ and gram- |
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Definition
-Gram+; L-ala, D-glu, L-lys, D-ala, D-ala
-Gram-; L-ala, D-glu, DAP, D-ala, D-ala
-DAP stands for meso Diaminopimelic acid |
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Term
| Go through the steps for peptidoglycan synthesis? |
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Definition
1. UDP is loaded up onto *GlcNAc which is then made into **UDP-MurNAc (uses MurA&B)
2. The *five AAs are loaded onto UDP-MurNAc (MurC-F)
3. UMP is released as MurNAc is attached to **bactoprenol in the plasma membrane (call this lipid I)
4. **GlcNAc is attached using MurG (call this lipid II)
5. A **pentaglycine unit is attached to the middle peptide (either L-lys for gram+, or DAP for gram-)
6. Bactoprenol uses the pyrophosphate bond to *translocate the building block outside the cell
===============V===============
7. **A transglycosylase attaches the MurNac (with the peptide) to the nascent pep chain
8. Finally, a **transpeptidase links the *pentaglycine to the first **D-ala of the nacent chain and cleaves the *terminal D-ala for the energy
-Note; *carboxypeptidases are what do the actual cleaving of the terminal D-ala units (probably a big enzyme) |
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Term
| Which are the "penicillin binding proteins"? |
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Definition
-Those are the transpeptidases
-PBP can be used interchangeably with transpeptidase |
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Term
| What is the attachment point for teichoic acid in pep? How is teichoic acid immunogenic? What is it's role, and what does it compare to? |
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Definition
-Attached via a phosphate group to muramic acid in peptidoglycan of *gram+ bacteria
-Remember, it is lipoteichoic acid when attached to the membrane (functions to hold the two together)
-It is immunogenic by activating the *alternative pathway of complement (no Ig needed) (similar to LPS in G-)
-It also plays a role in cell adherence (similar to *pili in G-) |
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Term
| What is the O-antigen? How long is it? What is it's purpose? |
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Definition
-It is the immunogenic portion of LPS in gram- bac
-It is a carbohydrate chain, 50-100 units in length
-It protects bac from bile salts, antibiotics, etc.
-It is protective for the bac, but also immunogenic
-It allows us to serotype (distinguish) some strains |
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Term
| What is the core polysaccharide, and what does it have? |
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Definition
-It is the shorter (9-12 sugars) less variable polysaccharide core to LPS that contains a unique *KDO group
-(2-keto-3-deoxyoctulosonic acid) |
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Term
| What is lipid A, and what is in it? |
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Definition
-It is the toxic part of endotoxin (i.e. LPS)
-Contains *phosphorylated D-glucosamine with FA attached
-Most common FA is *beta-hydroxymyristic acid |
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Term
| What is LOS? Where do we find it? |
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Definition
-It means lipooligosaccharide
-It is like LPS but without the O antigen
-Present in N. gonorrhoeae & N. meningitidis
-It is readily shed and an important virulence factor |
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Term
| What does lysozyme do? What will it produce upon treatment of gram+ & gram- bacteria? |
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Definition
-Lysozyme hydrolyzes the *GlcNAc-MurNAc bond
-Both this and penicillin produce protoplasts (cell wall gone) in gram+ and spheroplast (partially gone) in gram- bac |
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Term
| What makes acid-fast bacteria acid-fast? What is the stain? What are some examples? |
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Definition
-Acid-fast bacteria have *mycolic acid in the cell wall that is the basis for the staining method
-They resist the normal dilute acid wash decolorization of normal staining (hence the name acid-fast)
-The stain used has carbolfuchsin (stains red)
-**Mycobacteria and nocardia species are examples |
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Term
| Which is the bacteria with no cell wall. Give an example and what it causes? |
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Definition
-Mycoplasma species lack the cell wall, and instead have sterols similar to what we possess (cholesterol)
-M. pneumoniae causes walking pneumonia |
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