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Bacterial%20Morphology%20Arrangement

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Bacterial Morphology Arrangement 1. Bacilli a.Streptobacilli b. Bacilli 2. Cocci a. Cocci b. Doplococci c. Streptococci d. Staphylococci e. Sarcina ( 3D ) – PowerPoint PPT presentation

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Title: Bacterial%20Morphology%20Arrangement


1
Bacterial Morphology Arrangement
  • 1. Bacilli
  • a.Streptobacilli
  • b. Bacilli
  • 2. Cocci
  • a. Cocci
  • b. Doplococci
  • c. Streptococci
  • d. Staphylococci
  • e. Sarcina ( 3D )
  • f. Gaffkya ( 2D )

2
Common Shapes Arrangement
3
Bacterial morphologies (1)
4
Bacterial morphologies (2)
5
Bacterial morphologies (3)
6
Bacterial Morphology Arrangement
  • 3 Spirl
  • a. Vibrio
  • b. Spirillum
  • c. Spirochete

7
Bacterial morphologies (4)
8
  • Bacterial Cell Structures Functions

9
Size relationships among prokaryotes
10
Bacterial Cell Structure
  • Appendages - fdlagella, pili or fimbriae
  • Surface layers - capsule, cell wall, cell
    membrane
  • Cytoplasm - nuclear material, ribosome, mesosome,
    inclusions etc.
  • Special structure - endospore

11
Bacterial Cell Structure
12
  • Appendages
  • 1. flagella
  • Some rods and spiral form have this.
  • a). function motility
  • b). origin cell membrane flagella attach to
    the cell by hook and basal body which consists
    of set(s) of rings and rods
  • Gram - 2 sets of ring and rods, L, P,
    S, M rings and rods
  • e.g. E. coli
  • Gram S, M rings and rods
  • e.g. B. megaterium

13
Organ of bacterial locomotion
14
Structure of the flagellum
15
Flagella movement(1)
16
Flagella movement(2)
17
Flagella movement(3)
18
  • b).Origin (continued)
  • The structure of the bacterial flagella allows it
    to spin like a propeller and thereby propel the
    bacterial cell clockwise or counter clockwise
    ( Eucaryotic , wave like motion.
  • Bacterial flagella provides the bacterium with
    mechanism for swimming toward or away from
    chemical stimuli, a behavior is knows as
    CHEMOTAXIX, chemosenors in the cell envelope can
    detect certain chemicals and signal the flagella
    to respond.

19
  • c). position
  • monotrichous
  • lophotrichous
  • peritrichous
  • d). structure
  • protein in nature subunit flagellin

20
2. Pili or Fimbriae Shorter than flagella and
straighter , smaller. Only on some gram-
bacteria. a). function adhere. One of the
invasive mechanism on bacteria. Some pathogens
cause diseases due to this. If mutant
(fimbriae) not virulent. Prevent
phagocytosis.
21
pili - sex factor. If they make pili, they are
or donors of F factor. It is necessary for
bacterial conjugation resulting in the transfer
of DNA from one cell to another. It have been
implicated in the ability of bacteria to
recognize specific receptor sites on the host
cell membrane. In addition, number of bacteria
virus infect only those bacteria have F pilus.
22
  • b). Origin Cell membrane
  • c). Position common pili , numerous over the
    cell, usually called fimbriae sex pile, 1-4/cell
  • d). Structure composed of proteins which can
    be dissociated into smaller unit
  • Pilin . It belongs to a class of protein Lectin
    which bond to cell surface polysaccharide.

23
  • II. CELL SURFACE LAYER
  • 1. Capsule or slime layer
  • Many bacteria are able to secrete material that
    adheres to the bacterial cell but is actually
    external to the cell.
  • It consists of polypeptide and polysaccharide on
    bacilli. Most of them have only polysaccharide.
    It is a protective layer that resists host
    phagocytosis. Medically important.

24
2. Bacterial Cell Wall General structure
mucopolysaccharide i.e. peptidoglycan. It is
made by N-acetylglucosamine and N-acetylmuramic
acid. tetrapeptide ( L-alanine-
isoglutamine-lysine-alanine) is attached. The
entire cell wall structure is cross linked by
covalent bonds. This provide the rigidity
necessary to maintain the integrity of the
cell. N-acetylmuramic acid is unique to
prokaryotic cell.
25
Cell walls of bacteria(2)
26
Cell walls of bacteria(3)
27
Cell walls of bacteria(4)
28
Cell walls of bacteria(1)
29
Structure of peptidoglycan(1)
30
Structure of peptidoglycan(2)
31
  • (a). Gram positive bacterial cell wall
  • Thick peptidoglycan layer
  • pentaglycin cross linkage.
  • Teichoic acid ribitol TA glycerol TA
  • Some have peptioglycan teichoic acid.
  • All have lipoteichoic acid.

32
Function of TA Antigenic
determinant Participate in the supply of Mg to
the cell by binding Mg regulate normal cell
division. For most part, protein is not
found as a constituent of the G cell wall
except M protein on group streptococci
33
Structure of the Gram-positive Cell Wall
34
  • (b) Gram -
  • Thin peptidoglycan
  • Tetrapeptide cross linkage
  • A second membrane structure protein and
    lipopolysaccharide.
  • Toxicity endotoxin on lipid A of
    lipopolysaccharide. glucosamine-
    glucosamine-long
  • polysaccharide- repeated sequences of a few
    sugars (e.g. gal- mann-rham) n10-20 O antigen

35
Structure of peptidoglycan(3)
36
Toxicity endotoxin on lipid A of
lipopolysaccharide. glucosamine-
glucosamine-long FA FA FA FA
polysaccharide- repeated sequences of a few
sugars (e.g. gal- mann-rham) n10-20 O antigen
37
Chemistry of LPS
38
The Gram-negative outer membrane(1)
39
The Gram-negative outer membrane(2)
40
  • 2. Cell Membrane
  • Function
  • a. control permeability
  • b. transport es and protons for cellular
    metabolism
  • c. contain enzymes to synthesis and transport
  • cell wall substance and for metabolism
  • d. secret hydrolytic enzymes
  • e. regulate cell division.
  • Fluid mosaic model. phospholipid bilayer
    and protein (structure and enzymatic function).
    Similar to eukaryotic cell membrane but some
    differs. e.g. sterols such as cholesterol in Euk
    not in Prok.

41
The cytoplasmic membrane
42
Functions of the cytoplasmic membrane(1)
43
Functions of the cytoplasmic membrane(2)
44
Transport proteins
45
Classes of membrane transporting systems(1)
46
Classes of membrane transporting systems(2)
47
Classes of membrane transporting systems(3)
48
  • III. Cytoplasm
  • 80 water, nucleic acids, proteins,
    carbohydrates, lipid and inorganic ions etc.
  • 1. Bacterial chromosomes
  • a single large circular double stranded DNA no
    histone proteins. The only proteins associated
    with the bacterial chromosomes are the ones for
    DNA replication, transcription etc.
  • 2. Ribosome
  • protein synthesis

49
The bacterial chromosome and supercoiling
50
  • 3. Mesosomes
  • A large invaginations of the plasma membrane,
    irregular in shape.
  • a. increase in membrane surface, which may be
    useful as a site for enzyme activity in
    respiration and transport.
  • b. may participate in cell replication by serving
    as a place of attachment for the bacterial
    chromosome.

51
  • 4. Inclusions
  • Not separate by a membrane but distinct.
  • Granules of various kinds
  • glycogen,
  • polyhydroxybutyric acid droplets (PHB)
  • i.e. fat droplets
  • inorganic metaphosphate (metachromatic
    granules) - in general, starvation of cell for
    almost any nutrients leads to the formation of
    this to serve as an intracellular phosphate
    reservoir.

52
PHB
53
  • 5. Chromatophores
  • Only in photosynthetic bacteria and blue green
    algae. Prok. no chloroplast, pigment found in
    lamellae located beneath the cell membrane.

54
  • 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.

55

The process of endospore formation
  • 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.

56
Endospores
57
Negatively Stained Bacillus (A) Vegetative Cell 
(B)  Endospore
58
Dipicolinic acid
59
Vegetative/spore-containing cells(1)
60
Vegetative/spore-containing cells(2)
61
Detailed stepsin endospore formation(1)
62
Detailed stepsin endospore formation(2)
63
Detailed stepsin endospore formation(3)
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