bacterial shape , bacterial size and structure, cell wall of bacterial, gram positive and gram negative cell wall, bacterial spores, formation and structure of spores, movement of bacteria using various kind of fagylla, list of motile and non motile bacteria
7. negative staining
clear microorganisms against a
dark background
better view of microbial shape due to lack
of distortion
stain is not taken up by the
microorganism
very useful with microorganisms with
capsules
negatively stained mixed bacteria culture
9. These are structures surrounding the outside of the cell envelope. They
usually consist of polysaccharide; however, in certain bacilli they are
composed of a polypeptide (polyglutamic acid). They are not essential to
cell viability and some strains within a species will produce a capsule,
whilst others do not. Capsules are often lost during in vitro culture.
Attachment
Protection from phagocytic
engulfment.
Resistance to drying.
Depot for waste products.
Reservoir for certain
nutrients.
protection
10. Outside cell wall
Made of chains of
flagellin
Attached to a
protein hook
Anchored to the
wall and
membrane by the
basal body
They propel
bacteria around
16. Types of Flagella
Main function: to propel bacteria to and from area’s
of nutrients/toxic environments
17. Monotrichate/Amphitrichate/Lophotrichate/Peritrichate
Identification
of Bacteria
Pathogenesis
Motility of
bacteria
Some bacterial species are mobile and possess
locomotory organelles - flagella. Flagella consist of a
number of proteins including flagellin
The diameter of a flagellum is thin, 20 nm, and
long with some having a length 10 times the
diameter of cell. Due to their small diameter,
flagella cannot be seen in the light microscope
unless a special stain is applied. Bacteria can have
one or more flagella arranged in clumps or
spread all over the cell.
18. Present in spiral cells
Similar to flagella, but they wrap
around the cell
Corkscrew motion enables a
bacterium such as T.pallidum
(causative agent of Syphilis) to move
effectively through body fluids
(vaginal secretions)
19.
20. Short thin appendages
◦Fimbriae and pili
Help cells to adhere to
surfaces
◦Sex pili
Bridge between bacterial
cells for DNA transfer
21. Pili are hair-like projections of the cell , They are known
to be receptors for certain bacterial viruses. Chemical
nature is pilin
Classification and Function
a. Common pili or fimbriae: fine , rigid
numerous, related to bacterial adhesion
b. Sex pili: longer and coarser, only 1-4, related
to bacterial conjugation
c. COL-1 PILI
23. Fimbriae allow
attachment to
teeth, stones in
creeks, plastic
catheter's in
hospitals
Pili are used to
transfer DNA
from one cell to
another
Fimbriae
24. TYPE 1-THICK,H.A.,M.S eg.Esch.coli,Klebs.,
TYPE 2-NON-H.A., eg.
S.gallinarum,S.pullorum
TYPE 3-THIN,M.R., eg.klebs.,serratia
Type4- thinner,M.R.,H.A . Eg.proteus
TYPE 5-monopolar eg.one sps.
pseudomonas
TYPE 6-very long eg. One sps. Of klebs.
25. • Dormant cell
• Resistant to
adverse conditions
- high
temperatures
• Produced when starved
• Contain calcium
dipicolinate
DPA, Dipicolinic acid
• Bacillus and Clostridium
Identification of
Bacteria
Pathogenesis
Resistance
27. IV. Special Structure
* Endospores
Spore former: sporobactobacilli and sporosarcinae - no
medical importance. bacillus and clostridium have
medical importance.
* Position: median, sub-terminal and terminal have
small water, high calcium content and dipicolinic acid
(calcium dipicolinate)
extremely resistant to heat, UV, chemicals etc. may be
due to many S containing A.A for disulfide groups.
28. • After the active growth period approaching the
stationary growth phase, a structure called forespore
develops within the cells.
• It consists of coat, cortex and nuclear structure.
The process of endospore
formation
