M0RPHOLOGY OF M0RPHOLOGY OF BACTERIABACTERIA

INTRODUCTIONINTRODUCTION

size of bacteria 0.2-1.5 microns size of bacteria 0.2-1.5 microns in diameter,3-5 microns in length in diameter,3-5 microns in length 1 micron -one thousandth of a millimeter1 micron -one thousandth of a millimeter Microscopy- Light microscopeMicroscopy- Light microscope Phase contrastPhase contrast Dark fieldDark field Interference and polarizedInterference and polarized Electron microscopy Electron microscopy

STAININGSTAINING

Simple stainingSimple stainingNegative stainingNegative stainingImpregnation Impregnation stainingstainingDifferential stainingDifferential stainingGRAM STAININGGRAM STAININGACID FAST STAININGACID FAST STAINING

GRAM STAININGGRAM STAINING

GRAM Negative GRAM Positive GRAM Negative BACILLI GRAM Positive COCCI

SHAPES AND SHAPES AND ARRANGEMENTARRANGEMENT

Classified basedClassified based on shapes on shapes Cocci-pairs,tetrads,Cocci-pairs,tetrads, chains,clusterchains,cluster Bacilli-chains,Bacilli-chains, cuneiformcuneiform VibriosVibrios SpirillaSpirilla SpirochetesSpirochetes

BACTERIAL ANATOMYBACTERIAL ANATOMY

BACTERIAL ANATOMYBACTERIAL ANATOMY

CELLULAR COMPONENTSCELLULAR COMPONENTS

EXTRA CELLULAR COMPONENTSEXTRA CELLULAR COMPONENTS

CELLULARCELLULAR COMPONENTS COMPONENTS

CELL WALLCELL WALL confers shapeconfers shape Rigidity & ProtectionRigidity & Protection receptor sites for antibiotics and receptor sites for antibiotics and

bacteriophagesbacteriophages AntigenicAntigenic Bacterial cell walls are about 10-25nm thick and

accounts for about 20-30% of the dry weight of the cells

differs in Gram positive & differs in Gram positive & Gram negative bacteriaGram negative bacteria

GRAM POSITIVE CELL GRAM POSITIVE CELL WALLWALL

N acetyl N acetyl

glucosamine &N glucosamine &N acetyl muramic acetyl muramic acid– acid– PeptidoglycanPeptidoglycan

Teichoic acidTeichoic acid Antigens—proteins Antigens—proteins

& polysaccharides& polysaccharides

GRAM NEGATIVE CELL GRAM NEGATIVE CELL WALLWALL

Complex structureComplex structure Thinner Thinner

peptidoglycan layerpeptidoglycan layer Outer membrane Outer membrane

protein– thicker protein– thicker with phospholipids,with phospholipids,

proteins & proteins & lipopolysaccharides. lipopolysaccharides.

DEMONSTRATION OF DEMONSTRATION OF CELL WALL CELL WALL

PlasmolysisPlasmolysis MicrodissectionMicrodissection Antigen-antibody reactionAntigen-antibody reaction Differential stainingDifferential staining Electron microscopyElectron microscopy

DEFECTIVE CELL WALLDEFECTIVE CELL WALL

Result of cell wall lysisResult of cell wall lysis Defective synthesis or inhibition of Defective synthesis or inhibition of

synthesis of cell wallsynthesis of cell wall Gram positive bacteria– ProtoplastGram positive bacteria– Protoplast Gram negative bacteria– SpheroplastGram negative bacteria– Spheroplast L- formsL- forms MycoplasmaMycoplasma Pleomorphism & involution formPleomorphism & involution form

CYTOPLASMIC CYTOPLASMIC MEMBRANEMEMBRANE

semipermeablesemipermeable passage of nutrientspassage of nutrients excretory functionexcretory function maintains osmotic pressuremaintains osmotic pressure synthesis of many enzymessynthesis of many enzymes

CYTOPLASMCYTOPLASM

VISCOUS,WATERY, SOFT GELVISCOUS,WATERY, SOFT GEL containscontains ribosomes,mesosomesribosomes,mesosomes inclusion granulesinclusion granules -poly phosphates (metachromatic)-poly phosphates (metachromatic) -polysaccharides (starch)-polysaccharides (starch) -lipids (fat globules)-lipids (fat globules) plasmidsplasmids

RIBOSOMESRIBOSOMES

made of ribosomal RNA and made of ribosomal RNA and proteinsproteins

Site for protein synthesisSite for protein synthesis

Translation of genetic informationTranslation of genetic information

MESOSOMESMESOSOMES

invagination of cytoplasmic invagination of cytoplasmic membranemembrane

site for respiratory enzymessite for respiratory enzymes

takes part in cell divisiontakes part in cell division

NUCLEUSNUCLEUS

circular, coiledcircular, coiled double stranded DNAdouble stranded DNA length– 1mm(1000 microns)length– 1mm(1000 microns) genetic informationgenetic information no nuclear membraneno nuclear membrane

PLASMIDSPLASMIDS

extra chromosomal genetic elementsextra chromosomal genetic elements auto replicationauto replication not essential for viability of the cellnot essential for viability of the cell confers additional properties on the confers additional properties on the

cell -conjugationcell -conjugation -toxigenicity-toxigenicity -drug resistance-drug resistance

AUTOLYSINSAUTOLYSINS

lysosome which hydrolyze their own lysosome which hydrolyze their own cell wallcell wall

Normal function to remodel the cell Normal function to remodel the cell wall during growthwall during growth

Essential for cell septation, Essential for cell septation, sporulation & transformation sporulation & transformation

EXTRA CELLULAR EXTRA CELLULAR COMPONENTSCOMPONENTS

FLAGELLAFLAGELLA

Organ of locomotionOrgan of locomotion 3—20 microns in 3—20 microns in

lengthlength 0.013 microns thick0.013 microns thick Contains flagellin Contains flagellin

(myosin like protein)(myosin like protein)

FLAGELLA-contFLAGELLA-cont

Different types…Different types… monotrichousmonotrichous amphitrichousamphitrichous lophotrichouslophotrichous peritrichousperitrichous

DemonstrationDemonstration• Silver impregnation Silver impregnation

stainingstaining• Hanging dropHanging drop• SerologySerology

FIMBRIAE-PILIFIMBRIAE-PILI

Short, hair-like,thinShort, hair-like,thin

Common in GNBCommon in GNB

Made of pilinMade of pilin

HaemagglutinationHaemagglutination

Conjugation– sex piliConjugation– sex pili

CAPSULECAPSULE

External to the cell wallExternal to the cell wall

Thick & jelly likeThick & jelly like

May be made of polysaccharides, May be made of polysaccharides, polypeptides or hyaluronic acidpolypeptides or hyaluronic acid

Microcapsule—narrow & thin Microcapsule—narrow & thin (H.influenzae)(H.influenzae)

CAPSULE-FUNCTIONSCAPSULE-FUNCTIONS

Protection- against Protection- against phagocytes,phagocytes,

bacteriophages,enzymbacteriophages,enzymeses

Enhances bacterial Enhances bacterial virulencevirulence

AntigenicAntigenic Demonstrated by Demonstrated by India ink stainingIndia ink staining Quellung reactionQuellung reaction

CAPSULE contCAPSULE cont

BACTERIAL SPOREBACTERIAL SPORE

highly resistant formshighly resistant forms formed under adverse formed under adverse

conditionsconditions metabolically inactive, metabolically inactive,

resting stage.resting stage. multilayeredmultilayered can convert to actively can convert to actively

dividing vegetative dividing vegetative forms if conditions are forms if conditions are favorablefavorable

SPORES-cont SPORES-cont

TYPESTYPES Oval or spherical in Oval or spherical in

shapeshape Terminal ,sub terminal Terminal ,sub terminal

or centralor central Bulging or non bulgingBulging or non bulgingDEMONSTRATIONDEMONSTRATION• modified acid fast modified acid fast

stainingstaining• other special methodsother special methods