Download BACTERIAL STRUCTURE

BACTERIAL SURFACE STRUCTURES
BY2205 February 2011 – Prof. Peter Owen
Recommended General Textbooks:
** Prescott, Harley, & Klein: MICROBIOLOGY. McGraw Hill, 7th Ed., 2008, Ch.3**
(Wheelis: PRINCIPLES OF MODERN MICROBIOLOGY. Jones & Bartlett Pub, 2008, Ch. 4
Black: MICROBIOLOGY: Principles and Explorations. Wiley, 6th Ed., 2005, Ch. 4.
Perry, Staley & Lory: MICROBIAL LIFE. Sinauer Assoc. Pub., 2002, Ch. 4 [best on structure]
Todar’s ONLINE TEXTBOOK OF BACTERIOLOGY Ch. 3 Structure and Function of Bacterial
Cells: http://textbookofbacteriology.net/structure.html)
LECTURE TOPICS
ANATOMY OF GRAM+ve & GRAM-ve BACTERIA
BACTERIAL SURFACE STRUCTURES
A.
SURFACE APPENDAGES
1.
Flagella
2.
Fimbriae/Pili
B.
CAPSULES
C.
S-LAYERS
D.
GRAM-POSITIVE CELL WALL
1.
Peptidoglycan
2.
Teichoic Acids & Teichuronic Acids
3.
Wall-Associated Proteins
E.
GRAM-POSITIVE PLASMA MEMBRANE
1.
Proteins
2.
Lipids
3.
Lipoteichoic Acids
F.
GRAM-NEGATIVE PLASMA MEMBRANE
G.
GRAM-NEGATIVE PERIPLASMIC SPACE
H.
GRAM-NEGATIVE PEPTIDOGLYCAN LAYER
I.
GRAM-NEGATIVE OUTER MEMBRANE
1.
Proteins
2.
Lipids
3.
Lipopolysaccharides
Table 3. Properties of Some Bacterial Surface Structures
Structure
Composition
Function(s)
Flagella
>10 Protein subunits
Motility; (adhesion also in
some organisms)
Biotechnological Uses
Serotyping tool (H antigen);
experimental vaccines
F-(sex) pili
1 major protein subunit (F-pilin)
Sexual reproduction
Pili/
Fimbriae
1 major (pilin/fimbrin) and
several minor protein subunits;
tip subunit often binds to specific
molecules (receptors) on cell
surfaces
Adhesion to surfaces;
(twitching motility for Type
IV fimbriae)
Acellular vaccine component
(pertussis)
Capsules
Usually homo or
heteropolysaccharides
Thwarts hosts immune
system (e.g. by preventing
phagocytosis; by molecular
mimicry etc); protects against
desiccation; involved in
adhesion and biofilm
formation
Serotyping tool (K antigen);
vaccine component (vs e.g.
streptococcal, meningococcal
& haemophilus infections);
food additive (xanthan); gelling
agent (gellan); moisturising
agent in cosmetics
S-layers
Protein/glycoprotein subunit
Various (structural role;
exclusion barrier; adhesion;
protection vs phagocytosis)
Novel ultrafiltration
membranes of defined porosity
(mol. size cut off)