Bacteriology 1

Characteristics of Bacteria

1. Unicellular

2. No nucleus

3. Most have peptidoglycan cell wall

4. Multiply by binary fission

5. Can use a wide range of chemical substances for their nutrition

Bacterial Anatomy

Glycocalyx

Flagella

Cell wall

Pili

Axial Filament/Endoflagella/Periplasmic flagella

Cytoplasmic Membrane

Cytoplasm

Nucleoid

Plasmid

Ribosomes

Metachromatic Granules (Volutin)

Polysaccharide Granul

Lipid Inclusions

Sulfur Granules

Carboxysomes

Magnetosomes

Endospores

time for the bacteria to double in size and split into two

Generation Time

Bacterial Replication

Binary Fission

Viscous, gelatinous layer composed of polysaccharide and polypeptides.

Glycocalyx

Forms of Glycocalyx

Slime layer

Capsule

Biofilm

External layer which is unorganized and loosely attached

Slime layer

This is the Organized, firmly attached, formnog glycocalyx.

Capsule

Aggregated to form a colony

Biofilm

Functions of glycocalyx

✔ Adherence to tissue surface

✔ Prevents phagocytosis

✔ Inhibits nutrients from moving out of the cell

✔ Acts as a barrier to toxic hydrophobic molecules

✔ Identified by our antibody as K or V antigen in Salmonella

Example of capsulated bacteria

✔ Streptococcus pneumoniae

✔ Klebsiella pneumoniae

✔ Haemophilus influenzae

✔ Pseudomonas aeruginosa

✔ Neisseria meningitidis

✔ Cryptococcys neoformans

Organ for locomotion or motility

Flagella

Basic parts of flagellum

Filament

Hook

Basal body

Flagellin

long outer most region

Filament

where the filament is attached

Hook

anchors the flagellum to the cell wall and plasma

membrane

Basal body

This is a semirigid, helical structure that moves the cell by rotating from the basal body

prokaryotic flagellum

The rotation of a flagellum is either ___ or _____ around its long axis.

clockwise or counterclockwise

They undulate in a wavelike motion.

Eukaryotic flagella

Function of flagella

✔ Run and tumble movement

✔ Identified by our antibody as H antigen

✔ Taxis

Movement towards the stimulus by run or swim

Attractant

Movement away from the stimulus by tumble or twitch

Repellent

movement of a bacterium toward or away from a particular stimulus

Taxis

Types of Taxis

✔ Chemotaxis - chemicals

✔ Light - phototaxis

Types of motility

Run or swim

Tumble or twitch

Sliding or Gliding

Swarming

This type og motility is one direction for length of time

Run or swim

This type of motility is a periodic, abrupt, random changes in direction

Tumble or twitch

This type of motility is a semi solid surface ( spreading) and low water

Sliding or Gliding

This type of motility is a coordinated movement, rotating flagellum

Swarming

Types of Flagella

-Monotrichous

-Amphitrichous

-Lophotrichous

-Peritrichous

-Atrichous

-Cephalotrichous or Amphilophotrichous

Single polar flagellum can rotate both clocks and anticlockwise resulting in forwarding movement and backward movement

Monotrichous

One flagellum is present on each end. Movements are like monotrichous flagella.

Amphitrichous

Tufts of flagella present at one or both sides. Propagates clockwise and anticlockwise.

Lophotrichous

Numerous flagella are present all over the bacterial body, anticlockwise rotation produces one-directional movement.

Peritrichous

There is no flagellum.

Atrichous

Several flagella are present at both ends. Movements are similar to monotrichous flagella.

Cephalotrichous or Amphilophotrichous

Example of Monotrichous

Vibrio cholerae

Example of Amphitrichous

Alkaligens faecali

Example of Lophotrichous

Spirillum

Example of Peritrichous

Salmonella Typhi

Example of Atrichous

Lactobacillus

Example of Cephalotrichous or Amphilophotrichous

Pseudomonas

Outer covering of most of bacteria,

Cell Wall

Consist of peptidoglycan (MUREIN)

Cell Wall

Recognise as antigen O

Cell wall

Function of Cell wall

✔ Gives shape to cell

✔ Provide resistance to lysis by osmotic shock

✔ Anchorage of flagellum

Proteinaceous, hair-like appendage, shorter and thinner than flagella

Pili

refers to a class of fibrous proteins that are found in pilus structures in bacteria.

Pilin

Types of pili

1. Common pili, attachment pili, fimbriae

2. Sex pili, Conjugate pili, F pili

If function as attachment or adherence making the bacterium look-like porcupin

Common pili, attachment pili, fimbriae

Function as adherence, transfer of DNA for Bacterial mating - Conjugation

2. Sex pili, Conjugate pili, F pili

Pili are involve in the motility of other bacteria which are

Twitching motility

Gliding motility

This motility can be observe in Pseudomonas aeruginosa, Neisseria gonorrhoeae and some strains of Escherichia coli

Twitching motility

This motility can be observe in Myxobacteria

Gliding motility

Structure for motility found in spirochetes

Axial Filament/Endoflagella/Periplasmic flagella

Positioned beneath the bacterial outer membrane

Axial Filament/Endoflagella/Periplasmic flagella

Rotate around the body cell and gives the spirochete a twisting or corkscrew motion

Axial Filament/Endoflagella/Periplasmic flagella

Maintains cell integrity

Cytoplasmic Membrane

Protects cell from adverse changes in the outside environment

Cytoplasmic Membrane

Function of Cytoplasmic Membrane

✔ Regulates transport

✔ Specialized functions: Respiration, photosynthesis,macromolecules secretions from cytoplasm

Thick, aqueous, semitransparent and elastic, composed of 80% water

Cytoplasm

Function of Cytoplasm

✔ Suspend primarily important bacterial components and inclusions such as proteins (enzymes), carbohydrates, lipids, inorganic ions and many LMW compounds.

Single, long, continuous and frequent circular arranged thread of d/s DNA

Nucleoid

Extrachromosomal genetic elements and bot connected to the main bacterial chromosomes. It also replicated independently

Plasmid

Function of plasmid

✔ Carry genes for such activities as Abx resistance, tolerance to toxic metals and production of toxins
✔ Synthesis of certain enzymes

Composed of 50s and 30s subunit and site of protein synthesis

Ribosomes

Reserve of inorganic phosphate and can be used in the synthesis of ATP

Metachromatic Granules (Volutin)

Consist of glycogen and starch

Polysaccharide Granules

Lipid storage material

Lipid Inclusions

Present in “Sulfur Bacteria” -Thiobacillus species

Sulfur Granules

Oxidize sulfur and sulfur containing compound as a source of energy

Sulfur Granules

Used by “Photosynthetic bacteria”

Carboxysomes

Utilize Carbon dioxide as their source of Carbon that process is called Carbon dioxide fixation

Carboxysomes

Formed by several gram (-) bacteria such as Magnetospirillum manetotacticum

Magnetosomes

Act like magnets

Magnetosomes

Facilitated the downward movement until they reach suitable attachment site and decompose peroxides

Magnetosomes

Specialized resting cells and Highly durable and resistant to extreme conditions

Endospores

Rod - shape

Bacillus

Round shape

Coccus

Cork –screw shape

Spiral

Types of Bacillus

Diplobacilli

Streptobacilli

Diphtheriabacilli

Leprabacilli

Example of Diplobacilli

Klebsiealla pneumoniae

Example of Streptobacilli

Bacillus cereus

Example of Diphtheriabacilli

Cornebacterium diphtheriae

Example of Leprabacilli

Mycobacterium leprae

Type of coccus

Diplococci

Staphylococci

Streptococci

Tetrads

Sarcinae

Example of Diplococci

Neisseria gonorrhoeae

Example of Staphylococci

Staphylococcus aureus

Example of Streptococci

Streptococcus pyogenes

Example of Tetrads

Micrococcus species

Example of Sarcinae

Sarcina ventriculi

Types of Spiral

Vibrio

Spirillum

Spirochete

Example of Vibrio

Vibrio cholerae

Example of Spirillum

Spirillum volutans

Example of Spirochete

Treponema pallidum

Hierarchy of Biological Classification

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Specie

3 Domains of Life

-Archaea

-Bacteria

-Eurkarya

This domain possess genes and metabolic pathway closely related to eukaryotes

Archaea

This domain use more diverse energy source such as metal ions and hydrogen gas other than sugars

Archaea

This domain cannot perform both photosynthesis and carbon fixation

Archaea