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Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

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Bacterial Anatomy Bacterial Anatomy Rashmi.S Rashmi.S
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Page 1: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Bacterial AnatomyBacterial Anatomy

Rashmi.SRashmi.S

Page 2: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Anatomy of a Bacterial Cell

Page 3: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

DescriptionDescription

Bacteria are Prokaryotic, Bacteria are Prokaryotic, unicellular that do not contain unicellular that do not contain chlorophyll.chlorophyll.

Size of bacteria may range from Size of bacteria may range from 0.2-1.5 micrometer in diameter 0.2-1.5 micrometer in diameter and 3-5 micrometer in lengthand 3-5 micrometer in length

Page 4: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

DIFFERENCES BETWEEN PROKARYOTES AND DIFFERENCES BETWEEN PROKARYOTES AND EUKARYOTESEUKARYOTES

CharacterCharacter Prokaryotes Prokaryotes Eukaryotes Eukaryotes

Nucleus:Nucleus:Nuclear MembraneNuclear Membrane Absent Absent Present Present

Nucleolus AbsentNucleolus Absent Present Present Mitotic Division AbsentMitotic Division Absent PresentPresent

CytoplasmCytoplasmCytoplasmic Streaming AbsentCytoplasmic Streaming Absent PresentPresentPinocytosis Absent Pinocytosis Absent Present Present Lysosomes Absent Lysosomes Absent Present Present Golgi Apparatus AbsentGolgi Apparatus Absent PresentPresentEndoplasmic Reticulum AbsentEndoplasmic Reticulum Absent PresentPresentChemical CompositionChemical CompositionSterols AbsentSterols Absent PresentPresentMuramic Acid PresentMuramic Acid Present AbsentAbsentTeichoic Acid PresentTeichoic Acid Present AbsentAbsent

Page 5: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Classification of Bacteria based Classification of Bacteria based on their Shapeon their Shape

CocciCocci BacilliBacilli VibrioVibrio SpirillaSpirilla SpirochetesSpirochetes ActinomycetesActinomycetes MycoplasmaMycoplasma

Page 6: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Cellular Arrangement Cellular Arrangement

In Cocci,In Cocci, Diplococci: Cocci arranged in pairsDiplococci: Cocci arranged in pairs

Streptococci: Arranged in chainsStreptococci: Arranged in chains

Staphylococci: Arranged in grape like Staphylococci: Arranged in grape like clustersclusters

Page 7: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.
Page 8: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

In Bacilli,In Bacilli, Coccobacilli: Oval shapedCoccobacilli: Oval shaped

Palisades : Parallel, attached at any Palisades : Parallel, attached at any one end of the cellone end of the cell

Streptobacilli: In chainsStreptobacilli: In chains

Page 9: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.
Page 10: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

VibrioVibrio Spirilla

Page 11: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Actinomycetes Mycoplasma

Page 12: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Structure of a Bacterial CellStructure of a Bacterial Cell(Bacterial Anatomy)(Bacterial Anatomy)

Examination of a bacterial cell reveals Examination of a bacterial cell reveals components of structurescomponents of structures

Some external to cell wall Some external to cell wall

Others internal to cell wallOthers internal to cell wall

Page 13: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Anatomy of a Bacterial Cell

Page 14: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Demonstration of the cell Demonstration of the cell wallwall

PlasmolysisPlasmolysis MicrodissectionMicrodissection Specific AntibodiesSpecific Antibodies Differential StainingDifferential Staining Electron MicroscopeElectron Microscope

Page 15: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Structure of the cell wallStructure of the cell wall

Bacterial Bacterial cell wallcell wall provides structural provides structural integrity to the cell. integrity to the cell.

The bacterial cell wall differs from that of all The bacterial cell wall differs from that of all other organisms by the presence of other organisms by the presence of PeptidoglycanPeptidoglycan

Peptidoglycan (Mucopeptide) is composed of Peptidoglycan (Mucopeptide) is composed of alternating chains of ..alternating chains of ..

N -Acetyl Glucoseamine and N-Acetyl N -Acetyl Glucoseamine and N-Acetyl Muramic acid,Muramic acid, which is cross linked by which is cross linked by Peptide chainsPeptide chains

Page 16: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Structure of Peptidoglycan

Page 17: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

PeptidoglycanPeptidoglycan is responsible for is responsible for the rigidity of the bacterial cell the rigidity of the bacterial cell wall and for the determination of wall and for the determination of cell shapecell shape

Based on the Based on the composition of cell composition of cell wall & Stainingwall & Staining bacteria are bacteria are classified into “classified into “Gram positive”Gram positive” and and ““Gram Negative’Gram Negative’

Page 18: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Gram’s Staining

Page 19: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Gram Positive Cell wallGram Positive Cell wall

The The Gram positiveGram positive cell wall is cell wall is characterized by the presence of a characterized by the presence of a very thick very thick PeptidoglycanPeptidoglycan layer layer

20-80 nm thick20-80 nm thick Cell wall contains90% Peptidoglycan Cell wall contains90% Peptidoglycan

and 10%Teichoic acidand 10%Teichoic acid

Page 20: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.
Page 21: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Interwoven in the cell wall of gram-Interwoven in the cell wall of gram-positive are positive are Teichoic acidsTeichoic acids and and lipoteichoic acidslipoteichoic acids. .

Teichoic acids composed of polymers Teichoic acids composed of polymers of glycerol, phosphates, and the sugar of glycerol, phosphates, and the sugar alcohol- ribitol. alcohol- ribitol.

Page 22: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Teichoic acids constitute for the major Teichoic acids constitute for the major surface antigens.surface antigens.

Eg: In Eg: In Streptococcus pneumoniaeStreptococcus pneumoniae Teichoic acid bears the antigenic Teichoic acid bears the antigenic determinants called the “Forssman determinants called the “Forssman antigen”antigen”

Page 23: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Gram Negative Cell WallGram Negative Cell Wall

Gram negative cell wall contains a thin Gram negative cell wall contains a thin PeptidoglycanPeptidoglycan layer adjacent to the layer adjacent to the Cytoplasmic membraneCytoplasmic membrane, ,

In addition to the In addition to the PeptidoglycanPeptidoglycan layer, layer, the Gram negative cell wall also the Gram negative cell wall also contains an additional outer membrane contains an additional outer membrane composed by composed by PhospholipidsPhospholipids and and Lipopolysaccharide which face into the Lipopolysaccharide which face into the external environment. external environment.

Page 24: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.
Page 25: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

The LPS present on the Gm negative The LPS present on the Gm negative cell wall consists of 3 regions:cell wall consists of 3 regions:

Polysaccharide determining O antigenPolysaccharide determining O antigen Core PolysaccharideCore Polysaccharide Glycolipid portion /Lipid AGlycolipid portion /Lipid A

Page 26: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.
Page 27: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

All the three factors are responsible All the three factors are responsible for the endotoxic activities………for the endotoxic activities………

LPS Endotoxin causes a form of Septic LPS Endotoxin causes a form of Septic Shock for which there is no direct Shock for which there is no direct treatmenttreatment

Page 28: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Cytoplasmic MembraneCytoplasmic Membrane

It is a thin layer lining the inner It is a thin layer lining the inner surface of the cell wall.surface of the cell wall.

Semipermiable membrane controlling Semipermiable membrane controlling the flow of metabolitesthe flow of metabolites

Chemically ,consists of Lipoprotein Chemically ,consists of Lipoprotein and carbohydrates. Sterols are absentand carbohydrates. Sterols are absent

Page 29: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

CytoplasmCytoplasm

Colloidal system of variety of organic Colloidal system of variety of organic and inorganic solutes in Viscous and inorganic solutes in Viscous watery solutionwatery solution

No ER,& MitochondriaNo ER,& Mitochondria

Contains Mesosomes Inclusions and Contains Mesosomes Inclusions and VacuolesVacuoles

Page 30: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

MesosomesMesosomes

Vesicular, convoluted invaginations of Vesicular, convoluted invaginations of the plasma membranethe plasma membrane

Prominent in GM+ bacteriaProminent in GM+ bacteria Principal sites of Respiratory enzymesPrincipal sites of Respiratory enzymes Analogous to mitochondria in Analogous to mitochondria in

EukaryotesEukaryotes

Page 31: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

NucleusNucleus

Bacterial nuclei “Bacterial nuclei “have no nuclear have no nuclear membranemembrane “ “or the nucleolus.or the nucleolus.

Genome consists of a single double Genome consists of a single double stranded DNA.stranded DNA.

Might be a Circular form or may be Might be a Circular form or may be open under certain condition to form open under certain condition to form a long chain.a long chain.

Page 32: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

PlasmidsPlasmids

Extra chromosomal DNAExtra chromosomal DNA

Circular capable of autonomous Circular capable of autonomous replication.replication.

Transferred from one bacterium to Transferred from one bacterium to another .another .

Page 33: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

ImportanceImportance

Their presence confers Their presence confers certain special characters……certain special characters……

ToxigenicityToxigenicityAntibiotic ResistanceAntibiotic ResistanceAbility to use certain unusual Ability to use certain unusual

components as nutrientscomponents as nutrients

Page 34: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Structures external to Structures external to BacteriaBacteria

CapsuleCapsule

FlagellaFlagella

Pili(Fimbriae)Pili(Fimbriae)

Page 35: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

CapsuleCapsule

Viscid material secreted by bacteria Viscid material secreted by bacteria around the cell surfacearound the cell surface

CapsuleCapsule is a sharply defined, organized is a sharply defined, organized structure (structure (Eg: Eg: PneumococcusPneumococcus))

Loose undemarkated structure as in Loose undemarkated structure as in Lueconostoc Lueconostoc is a is a Slime layer.Slime layer.

Page 36: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Colorless capsule surrounding the bacterial cell

Page 37: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Capsular Staining

Page 38: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Most bacterial capsules are composed Most bacterial capsules are composed of Polysaccharidesof Polysaccharides

Eg: Eg: Klebsiella pneumoniaeKlebsiella pneumoniae

A few capsules are PolypeptidesA few capsules are Polypeptides

Eg: Eg: Bacillus anthracisBacillus anthracis

Page 39: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Quellung ReactionQuellung Reaction

Described by Described by Neufeld(1902).Neufeld(1902). Serological method of demonstrating the Serological method of demonstrating the

capsule.capsule. Suspension of capsulated bacterium is Suspension of capsulated bacterium is

mixed with its specific anticapsular mixed with its specific anticapsular serum & examined under the serum & examined under the microscope ,capsule appears prominent microscope ,capsule appears prominent & swollen.& swollen.

Used to type Used to type Pneumococci.Pneumococci.

Page 40: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.
Page 41: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Functions of CapsulesFunctions of Capsules

Antiphagocytic,thus contribute Antiphagocytic,thus contribute “Virulence”.“Virulence”.

Protects against “Lysozyme”Protects against “Lysozyme” Promote attachment of bacteria to Promote attachment of bacteria to

surface(Eg: surface(Eg: StreptococcusStreptococcus mutansmutans).). Permits bacteria to adhere to Permits bacteria to adhere to

Medical Implants & Catheters.Medical Implants & Catheters.

Page 42: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Toxicity to host cell – Eg: Toxicity to host cell – Eg: BacteroidesBacteroides fragilis.fragilis.

Provide protection against Provide protection against temporary drying.temporary drying.

Block the attachment Block the attachment ofBacteriophagesofBacteriophages..

Page 43: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Applications:Applications:

Used in serological typingUsed in serological typing

Detection of capsule in Blood, CSF Detection of capsule in Blood, CSF provides a rapid method of diagnosisprovides a rapid method of diagnosis

Used in preparation of vaccinesUsed in preparation of vaccinesEg: H.influenzaeEg: H.influenzae

Page 44: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

FlagellaFlagella

Unbranched, long ,filaments ,made up Unbranched, long ,filaments ,made up of protein “of protein “FlagellinFlagellin””

Organs of locomotionOrgans of locomotion

Found in all motile bacteria except Found in all motile bacteria except SpirochetesSpirochetes

Page 45: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Flagella are highly antigenic,Flagella are highly antigenic,

Termed as the Termed as the ‘H’ Antigen‘H’ Antigen..

Some of the immune responses are Some of the immune responses are directed against these proteins.directed against these proteins.

Page 46: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

StructureStructure

3-20 Micrometer.3-20 Micrometer.

Each flagellum consists of 3 partsEach flagellum consists of 3 parts

1.Filament 1.Filament

2.Hook2.Hook

3.Basal body3.Basal body

Page 47: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.
Page 48: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.
Page 49: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Flagellar Arrangement

Page 50: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Kinds of MotilityKinds of Motility:: Darting motilityDarting motility : : V.choleraeV.cholerae Tumbling motilityTumbling motility::

L.monocyctogenesL.monocyctogenes Cork &screw motilityCork &screw motility:: T.pallidumT.pallidum Stately motile Stately motile : : Clostridium Clostridium

spp.spp. Serpentine motilitySerpentine motility: : Salmonella Salmonella

(Except S.gallonarum pullorum)(Except S.gallonarum pullorum)

Page 51: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Detection of motility :Detection of motility :

Direct observation by hanging Direct observation by hanging dropdrop

Dark field microscopyDark field microscopyMotility mediaMotility media

Page 52: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Flagellar stainingFlagellar staining

Electron microscopyElectron microscopy

Immunological detection Immunological detection of “H” antigenof “H” antigen

Page 53: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

FimbriaeFimbriae

Hair like surface appendagesHair like surface appendages

0.5-10 nm thick0.5-10 nm thick

Shorter thinner than flagellaShorter thinner than flagella

Formed of protein subunits – PilinFormed of protein subunits – Pilin

Page 54: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

FunctionsFunctions

Organs of adhesionOrgans of adhesion Forms “Pellicles”Forms “Pellicles” Hemagglutination –Clumping of RBC’s Hemagglutination –Clumping of RBC’s

((EscherichiaEscherichia,,KlebsiellaKlebsiella)) Special type of Fimbriae called Sex Special type of Fimbriae called Sex

pili,help in attachment to other pili,help in attachment to other bacteriabacteria

Page 55: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

EndosporesEndospores Highly resistant stages of bacteriaHighly resistant stages of bacteria

Spores germinate to form a single Spores germinate to form a single Vegitative cell.Vegitative cell.

It is formed inside the cell .It is formed inside the cell .

Eg: Eg: BacillusBacillus, , ClostridiumClostridium

Page 56: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Endospore

Page 57: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Core contains the Nuclear bodyCore contains the Nuclear bodySurrounded by a Spore Wall.Surrounded by a Spore Wall.Outside this is a thick Spore Outside this is a thick Spore

cortexcortexThis is covered in turn by a This is covered in turn by a

tough Spore coat.tough Spore coat.Exosporium is additional outer Exosporium is additional outer

covering, which exhibits ridges covering, which exhibits ridges and groovesand grooves

Page 58: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Factor responsible for the resistance Factor responsible for the resistance of sporesof spores

Presence of calcium dipicolinic acidPresence of calcium dipicolinic acid

Page 59: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Endospore inside bacteria

Page 60: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Position of SporesA = oval, terminal;

B = rectangular, terminal;

C = rectangular, sub terminal,

D = rectangular, central;

E = circular, terminal;

F = circular, central;

G = terminal, club-shaped.

Page 61: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Pleomorphism and Involution Pleomorphism and Involution formsforms

Process of exhibiting variation in the shape Process of exhibiting variation in the shape and size of individual cells – Pleomorphismand size of individual cells – Pleomorphism

Eg: H.influenzaeEg: H.influenzae Certain bacteria exhibit swollen and Certain bacteria exhibit swollen and

aberrant forms in ageing cultures – aberrant forms in ageing cultures – Involution formsInvolution forms

This may be due to defective cell wall This may be due to defective cell wall synthesis or due to Autolytic Enzymessynthesis or due to Autolytic Enzymes

Eg: Eg: Yersinia, GonococcusYersinia, Gonococcus

Page 62: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

Protoplasts,Spheroplasts and Protoplasts,Spheroplasts and L-FormsL-Forms

Removal of bacterial cell wall by Removal of bacterial cell wall by hydrolysis with Lysozyme or hydrolysis with Lysozyme or antibiotics like Penicillin, liberates ..antibiotics like Penicillin, liberates ..

““Protoplasts” from Gram positive cellsProtoplasts” from Gram positive cells ““Spheroplasts” from Gram negative Spheroplasts” from Gram negative

cellcell

(retain the outer membrane and PG.)(retain the outer membrane and PG.)

Page 63: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

When Protoplasts and Spheroplasts When Protoplasts and Spheroplasts are able to grow and divide they are are able to grow and divide they are called the called the L-Forms.L-Forms.

First observed by Kleineberger-NobelFirst observed by Kleineberger-Nobel Named it as L forms after Lister Named it as L forms after Lister

Institute London.Institute London.

Eg: Streptobacillus moniliformisEg: Streptobacillus moniliformis

Page 64: Bacterial Anatomy Rashmi.S. Anatomy of a Bacterial Cell.

THANK YOUTHANK YOU


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