morphology of bacteria powerpoint presentation

1. M0RPHOLOGY OF BACTERIA
lnr89

2. INTRODUCTION
 Size of bacteria 0.2-1.5 microns in diameter,
3-5 microns in length.
 1 micron -one thousandth of a millimeter.
 Microscopy- Light microscope
Phase contrast
Dark field
Interference and polarized
Electron microscopy

3. STAINING
Simple staining
Negative staining
Impregnation
staining
Differential staining
GRAM STAINING
ACID FAST STAINING

4. GRAM STAINING
GRAM Negative GRAM Positive GRAM Negative BACILLI
GRAM Positive COCCI

5. SHAPES AND ARRANGEMENT
Classified based on shapes
Cocci-pairs,tetrads,
chains,cluster
Bacilli-chains,
cuneiform
Vibrios
Spirilla
Spirochetes

6. BACTERIAL ANATOMY

7. BACTERIAL ANATOMY
CELLULAR COMPONENTS
EXTRA CELLULAR COMPONENTS

8. CELLULAR
COMPONENTS

9. CELL WALL
Confers Shape
Rigidity
Protection
Receptor Sites For Antibiotics &
Bacteriophages
Antigenic
Differs In Gram Positive & Gram Negative
Bacteria

10. GRAM POSITIVE CELL WALL
N acetyl glucosamine
& N acetyl muramic acid–
Peptidoglycan
Teichoic acid
Antigens—proteins &
polysaccharides

11. GRAM NEGATIVE CELL WALL
 Complex structure
 Thinner peptidoglycan
layer
 Outer membrane
protein– thicker with
phospholipids,
proteins &
lipopolysaccharides.

12. DEMONSTRATION OF CELL WALL
Plasmolysis
Microdissection
Antigen-antibody reaction
Differential staining
Electron microscopy

13. DEFECTIVE CELL WALL
 Result of cell wall lysis
 Defective synthesis or inhibition of
synthesis of cell wall
 Gram positive bacteria– Protoplast
 Gram negative bacteria– Spheroplast
 L- forms
 Mycoplasma
 Pleomorphism & involution form

14. CYTOPLASMIC MEMBRANE
Semipermeable
Passage of nutrients
Excretory function
Maintains osmotic pressure
Synthesis of many enzymes

15. CYTOPLASM
VISCOUS,WATERY, SOFT GEL
contains
ribosomes,mesosomes
inclusion granules
-poly phosphates (metachromatic)
-polysaccharides (starch)
-lipids (fat globules)
plasmids

16. RIBOSOMES
Made of ribosomal RNA and proteins
Site for protein synthesis
Translation of genetic information

17. MESOSOMES
Invagination of cytoplasmic membrane
Site for respiratory enzymes
Takes part in cell division

18. NUCLEUS
Circular, coiled
Double stranded DNA
Length– 1mm(1000 microns)
Genetic information
No nuclear membrane

19. PLASMIDS
Extra chromosomal genetic elements
Auto replication
Not essential for viability of the cell
Confers additional properties on the
cell - Conjugation
- Toxigenicity

20. AUTOLYSINS
Lysosome which hydrolyze their own cell wall
Normal function to remodel the cell wall
during growth
Essential for cell septation, sporulation &
transformation

21. EXTRA CELLULAR
COMPONENTS

22. FLAGELLA
Organ of
locomotion
3—20 microns in
length
0.013 microns thick
Contains flagellin
(myosin like protein)

23. FLAGELLA-cont
Different types:
monotrichous
amphitrichous
lophotrichous
peritrichous

24. FLAGELLA-cont
Demonstration
•Silver impregnation staining
•Hanging drop
•U- tube or craigie tube
•Serology

25. FIMBRIAE-PILI
Short, hair-like, thin
Common in GNB
Made of pilin
Haemagglutination
Conjugation– sex
pili

26. CAPSULE
External to the cell wall
Thick & jelly like
May be made of polysaccharides,
polypeptides or hyaluronic acid
Microcapsule—narrow & thin (H.influenzae)

27. CAPSULE-FUNCTIONS
Protection- against
phagocytes, bacteriophages,
enzymes.
Enhances bacterial
virulence
Antigenic
Demonstrated by
India ink staining
Quellung reaction

28. CAPSULE cont

29. BACTERIAL SPORE
Highly resistant forms
Formed under adverse
conditions
Metabolically inactive,
resting stage.
Multilayered
Can convert to actively
dividing vegetative forms if
conditions are favorable

30. SPORES-cont
TYPES
Oval or spherical in shape
Terminal ,sub terminal or
central
Bulging or non bulging
DEMONSTRATION
• modified acid fast staining
• other special methods

31. THANK YOU