1. LADY AMRITBAI DAGA COLLEGE SHANKAR NAGAR
NAGPUR-440010,
RAMABAI BARLINGAY SCHOOL OF BIOTECHNOLOGY
TOPIC : PROKARYOTES ; BACTERIAL STRUCTURE AND
MORPHOLOGY, ENDOSPORE FORMING BACTERIA,
PSEUDOMONAS, MYCOBACTERIA, ARCHAEBACTERIA
NAME : RUCHI AJAY MISHRA
CLASS : M.Sc. BIOTECHNOLOGY SEM – II
ACADEMIC YEAR : 2021-22
3. INTRODUCTION
• Bacteria is unicellular, free-living, microscopic microorganisms capable of performing all the
essential functions of life.
• Antoni Van Leeuwenhoek first observed bacteria in the year 1676.
• They possess both deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA).
• Bacterial are prokaryotic microorganisms that do not contain chlorophyll.
• They occur in water, soil, air, food, and all natural environment.
• They can survive extremes of temperature, pH, oxygen, and atmospheric pressure.
• Bacteria are very small microorganisms which are visible under the microscope.
• They are having the size range microns.
• Bacteria are stained by staining reagents and then visualized under high power of magnification
(1000X) of compound microscope.
• An electron microscope is used for clear visualization of internal structure of bacteria.
4. SHAPE OF BACTERIA:-
On the basis of shape bacteria are classified as:-
1. Cocci
2. Bacilli
3. Vibrios
4. Spirilla
5. Spirochetes
6. Actinomycetes
7. Mycoplasma
5. SHAPE OF BACTERIA ;-
COCCI :-
• Cocci are small, spherical or oval cells.
• . In Greek “kokkos” means berry. Eg ; micrococcus .
BACILLI :-
• They are rod shaped cells. E.g. ; Bacillus anthracis.
• It is derived from Greek word “ Bacillus” meaning stick.
• In some of the bacillary forms are known as coccobacilli
• E.g. ; Bracella.
6. VIBRIOS : -
• They are comma shaped curved rods.
• E.g. ; Vibrio comma
SPIRILLA ;-
• They are longer rigid rods with several curves or coils.
• They have a helical shape and rigid body.
• E.g. : Spirillum ruprem.
SPIROCHETES : -
• They are slender and flexuous spiral forms.
7. ACTINOMYCETES : -
• The characteristic shape is due to the presence of rigid cell wall . Eg ; Streptomyces
• They are branching filamentous bacteria. E.g. ; Streptomyces species.
MYCOPLASMA :-
• Mycoplasma’s are spherical to filamentous cell with no cell wall.
• There is an attachment organelle at the tip of filamentous M. pneumoniae, M. genitalium ,
and several other pathogenic mycoplasmas.
8. BACTERIAL ANATOMY (STRUCTURE)
• In the bacteria the outer layer or cell envelop or bacteria consist of two things.
a) provide rigid support while freely permeable to solute.
b) underlaying cytoplasmic membrane or plasma membrane.
• It include granules, ribosomes, mesosomes and circular DNA.
• Some bacteria in addition to possess additional structure such as gelatinous material which cover
it is called as capsule when it is too thin it is called as microcapsule.
STRUCTURE :
• Cell wall
• Cytoplasmic membrane
• Cytoplasm
• Bacteria capsule
• Flagella
• Fimbria (pili)
9. BACTERIAL CELL WALL
CELL WALL :
• Peptido-glycan polymer (amino acid + sugars)
• Sugars : NAG & NAM (N- acetylglucosamine , N- acetylmuramic acid)
• Peptidoglycan is a huge polymer of interlocking chains of identical peptidoglycan monomers.
• It is present in both gram positive and gram negative bacteria.
• some bacteria called gram negative bacteria have an additional layer of membrane that contains lipopolysaccharide. –this extra layer
layer inhibits the uptake of antibiotics – protecting the bacteria.
FUNCTIONS :
• Protection of internal structure.
• Give shape to the cell .
• Confers rigidity & ductility.
• Role in division of bacteria.
• Offers resistance to harmful effect of environment.
• Contains receptor site for antibiotics .
• Provide attachment to complement.
10. CYTOPLASMIC MEMBRANE
• Thin semipermeable membrane which lies just beneath the cell wall that is called as cytoplasmic membrane”.
• The whole bacterial cytoplasm is bound peripherally by very thin,
elastic and semipermeable cytoplasmic membrane also known
as cell membrane or plasma membrane.
• Electron microscope shows the presence of three layer constituting
a unit membrane structure. It is 5-10mm in width.
FUNCTION :
• Transport :- a. active transport , b. passive transport
• Active transport : it is site of numerous enzymes (oxidase, polymerase, permease) involved in the active transport of selective
nutrients. It is impermeable to macromolecules and ionized substance.
• Passive transport : it is act as semipermeable membrane through inward and outward passage of water and passive transport of
molecule lipid soluble solutes take place by diffusion.
• Concentration : it is also concentration sugar, amino acids and phosphate so that the 300-400 fold gradient exist across atomic
barrier.
• Enzymatic function : it also contain cytochrome oxidase, enzyme of tricarboxylic acid cycle and polymerizing enzyme necessary
for synthesis of cell wall.
11. CYTOPLASM & BACTERIAL CAPSULE
CYTOPLASM:
• “Bacterial cytoplasm is suspension of organic and inorganic solutes in viscous watery solution”.
• It is not exhibiting protoplasmic streaming and it lacks endoplasmic reticulum or mitochondria.
• All the organelles which cytoplasm contains is as follows ;
• Ribosomes
• Polysomes
• Two types of Mesosomes.
a. Septal mesosome
b. Lateral mesosomes
BACTERIAL CAPSULE:
• “It is an outer covering of thick jelly like material that surrounds the bacterial cell wall”.
• Width: 0.2mm and contain 90% water and 2% solid.
• The solid constitutes may be complex polysaccharide (pneumococcus klebsiella, Enterobacter)
or polypeptides (anthrax bacillus) hyaluronic acid (streptococcus)
12. FLAGELLA & FIMBRIA
FLAGELLA
• These are long, sinuous contractile filamentous appendages known as “Flagella”.
• Composed of filament, hook, and basal body.
• Flagellin protein (filament) is deposited in helix at the lengthening tip.
• Basal body anchors filament and hook to cell wall by rod and a series of either two
or four ring of integral protein.
• Function :
It is responsible for bacterial motility- Motility may be observed microscopically or
by detecting the spreading growth in semi solid agar medium.
FIMBRIA (PILI)
• “Fimbria are filamentous, short, thin, straight, hair like appendages.
• Fimbriae are seen only in gram negative bacteria.
• They are composed of protein known as pilin (mw 18000Dalton)
• Function:
• Fimbria is an organ of adhesion and they are antigenic.
• Agglutination & pellicle formation.
• Genetic material is transferred from the donor to recipient cell.
13. ENDOSPORE FORMING BACTERIA
• Bacterial spores are dormant forms of bacteria which are thick walled, highly refractile and resistant.
• Nutritional deprivement (depletion of N2 or C source both) is the triggering factor.
• Exposure to suboptimal temperature.
• SPORE FORMATION :
Stage I Pro – sporulation phase
DNA assembles as an axial filaments.
Stage II Spore septum formation
Stage III Engulfment of the forespore
Stage IV Cortex formation
Stage V Synthesis of spore coats, DIPICOLINIC ACID, calcium uptake
Stage VI Spore nutrition (coats more thick)
Stage VII Lysis of cell and liberation of mature spore.
ENDOSPORE:
Formed inside the parent vegetative cell.
Endospore are highly durable dehydrated cells, which can survive extreme heat, lack of water, freezing and exposure to many toxic chemicals
and radiation.
It is also known as “resting cells”.
14. PSEUDOMONAS
• A large group of aerobic, non sporing gram negative (rods) bacteria motile by polar flagella.
• Found in water, soil and other moist environment some of them are pathogenic to plants.
• They are slender gram negative bacillus ; 1.5-3 microbes x 0.5 microns.
• Non capsulated but many strains have mucoid slime layer.
• Isolates from Cystic fibrosis patients have abundance of extracellular polysaccharide composed of alginate polymer.
GROWTH CHARECTERISTICS
• Obligate aerobe, but grow anaerobically if nitrate is if nitrate is available.
• Growth occurs at wide range of temp 6-42 degree Celsius the optimum being 37c
• Iridescent patches with metallic sheen are seen in cultures on nutrient agar.
• In broth forms dense turbidity with surface pellicle.
RESISTANCE
• Killed at 55oC in on 1 hour. Resistance to quaternary ammonium compounds.
• High resistance to chemical agents. Sensitive to acids silver salts, beta glutaraldehyde.
WHAT ANTIBIOTICS TO USE
• Aminoglycosides
• Gentamycin, Cephalosporin, Ceftazidime.
15. MYCOBACTERIUM
• Name from Myco and Bacteria, Fungus like bacteria as it forms mould like growth on liquid culture.
• M. Tuberculosis (T.B.) & M. Leprae (Leprosy) are the mycobacteria that infect humans.
• Mycobacteria are neither gram positive, nor gram negative it is acid fast bacteria.
• They have mycolic acid in their cell wall which makes them acid fast.
GROWTH CHARACTERISTICS :
• Obligate aerobes
• Grow slowly – generation time 15hrs.
• Colonies appear in two weeks.
• Optimum temp is 37 degree.
• Solid media most commonly used – LJ (Lowenstein Jensen) media.
TREATMENT AND RESISTANCE :
• DOTS – directly observed treatment short course – HRZE for 4 months & HRFOR 2 MONTHS.
• H- Isoniazid, R- Rifampicin, Z- Pyrazinamide, E- Ethambutol.
16. ARCHAEBACTERIA
• Archaebacteria are the large group of primitive bacteria having unusual cell walls, membrane lipids, ribosomes and RNA sequences,
and having the ability to produce methane and to live in anaerobic, extremely hot, salty, or acidic condition.
SIZE AND SHAPE :-
• Archaea are slightly less then 1micron long.
• In order to see their cellular feature scientists use electron microscope.
• Shape can be spherical or ball shaped and are called coccus. Other are rod shaped, long and thin, and labeled bacillus.
17. STRUCTURE AND CLASSIFICATION
• PHOSPHOLIPIDS
The molecules that make up cell membrane are called phospholipids, which act as building blocks for the cell. In
archaea, these molecules are made of glycerol-ether lipids.
ETHER BONDING
The ether bonding makes it possible for archaea to survive in environments that are extremely acidic or alkaline,
or that have great extremes in temperature.
ARCHAEBACTERIA IS CLASSIFIED IN FIVE PHYLUM :
• Crenarchaeota
• Euryarchaeota
• Korarchaeota
• Thuamarchaeota
• Nanoarchaeota
18. CONCLUSION
• Prokaryotes are important to all life on earth for a numbers of reasons. They play a critical role in the recycling of
nutrients by decomposing dead organisms and allowing their nutrients to be re-used.
• Prokaryotes play a major role in the nitrogen cycle by fixing atmospheric nitrogen into ammonia that plants can use
and by converting ammonia into other forms of nitrogen sources.
• It is important to know the morphological structure of microbes, as it provides us with a better understanding of
microbial physiology, pathogenic mechanisms, antigenic features, and allow us to identify them by species.
• Spore-forming bacteria play an important role in food spoilage and foodborne disease.
• They have made possible our understanding, at the molecular level, of hundreds of disease-relevant proteins that in
turn has enabled rational drug design to improve human health.
• Pseudomonas aeruginosa has beneficial uses in various industrial and commercial sectors around the globe. These
includes waste degradation, oil refineries, textile product, agriculture, pulp & paper, mining and explosive industries.
• Archaebacteria such as Thermus aquaticus is used to obtain Taq polymerase enzyme which is used in recombinant
DNA technology.
