morphology of bacteria


×
Rating : Rate It:
 
 
andrew    on Dec 04, 2013 Says :

nice ppt
Post a comment
    Post Comment on Twitter
Comments:  



  Notes
 
 
1 : BY Dr.S.KRITHIKAA I Yr MD MICROBIOLOGY V.M.K.V.M.C&H SALEM MORPHOLOGY OF BACTERIA
2 : CLASSIFICATION OF MICROORGANISMS MICROORGANISMS PLANTS PROTISTA ANIMALS PROKARYOTES EUKARYOTES Bacteria & blue green fungi, algae, slime algae moulds& protozoa
3 : PROPERTIES OF PROKAYOTIC &EUKARYOTIC CELLS
4 : STRUCTURE OF PROKARYOTIC &EUKARYOTIC CELLS
5 : MORPHOLOGY OF A BACTERIAL CELL SIZE SHAPE & ARRANGEMENT ANATOMICAL STRUCTURES - CELL WALL - CELL MEMBRANE - CYTOPLASM - SLIME LAYER & CAPSULE APPENDAGES- FLAGELLA & FIMBRIAE SPORES
6 : SIZE 3-5 *0.2-1.5 µm EPULOPISCIUM FISHELSONII- largest bacterium of size 600* 80 µm DEMONSTRATION- electron microscopy, coulter chamber, counting chamber, epifluroscence technique
7 : SHAPE COCCI- spherical or oval cells BACILLI- rod shaped COCCOBACILLI-length is same as width SPIROCHAETES- slender flexuous spiral forms VIBRIOS- comma shaped SPIRILLA- rigid spiral forms ACTINOMYCETES- branching filamentous bacteria resembling fungi MYCOPLASMA- round or oval bodies & interlacing filaments (cell wall deficient)
8 : ARRANGEMENT STREPTO- chains DIPLO- pairs STAPHYLO- clusters TETRADS- groups of four SARCINA- groups of eight CUNEIFORM- chinese letter pattern
9 : DEMONSTRATION Simple staining- crystal violet gentian violet carbol fuschin, saffranin differential staining – grams stain acid fast stain
10 : DIFFERENT SHAPES AND ARRANGEMENT
11 : ANATOMY
12 : CELL WALL Tough & rigid structure Made of peptidoglycan –mucopeptide(murein) composed of N-acetyl muramic acid & N- acetyl glucosamine alternating in chains cross linked by peptide subunits
13 : GRAM POSITIVE CELL WALL tightly cross linked peptides- d-alanine & d- glutamic acid Thickness- 18-80 nm & constitutes 40-80% of the dry weight Techoic acid- water soluble polymers of glycerol phosphate or ribitol phosphate residues two types – wall techoic acid-ribitol &membrane techoic acid- glycerol functions- cell wall stability, association of wall with membrane, adherence, reproduction
14 : CONTD… Polysaccharides- mannose, arabinose , rhamnose, glucuronic acid & mannuronic acid Thick peptidoglycan layer S LAYER- protein or glycoprotein molecules that self assemble on the outer surface of the organism. Protect from stressful environments, inhibit phagocytosis, contribute to virulence
15 : PEPTIDOGLYCAN LAYER OF GRAM POSITIVE CELL WALL
16 : GRAM NEGATIVE CELL WALL Thickness- 3-4 nm Loosely crosslinked by d- diaminipimelic acid or lysine Outer membrane- bilayered LPS containing OMPs – porins, OmpC, D, F, PhoE, LamB,Tsx contains 3 regions- I- polysaccharide determining O ag specificity II- core polysaccharide containing 3-deoxy-D- mannulooctulusonate(KDO) & heptose III- glucolipid responsible for endotoxicity
17 : CONTD... Lipoprotein layer- connects peptidoglycan to outer membrane & stabilizes the outer membrane Periplasmic space- space between inner& outer membranes containing the peptidoglycan layer and gel like solution of proteins & membrane derived oligosaccharides Thin peptidoglycan layer
18 : PORINS
19 : PEPTIDOGLYCAN OF GRAM NEGATIVE CELL WALL
20 : ACID FAST CELL WALL Lipids constitute 60% of the dry weight & are made of mycolic acid Responsible for virulence, cytotoxicity, granuloma formation, adjuvanticity Also contains phosphatidylinositol mannosides & lipoarabinimannan Polysaccharide- arabinogalactans
21 : CONTD… Trehalose sulpholipid- 2,3,6,6’ tetracylhelose-2 sulphate- prevents phagosome lysozyme fusion fusion following phagocytosis Proteins- act as porins & involved in biosynthesis of cell wall polymers
22 : STRUCTURE OF ACID FAST CELL WALL
23 : FUNCTIONS OF CELL WALL Accounts for the shape of the cell Protects the cell against osmotic damage Confers rigidity Cell division Target site for antibiotics, lysozymes, bacteriophages Carries bacterial antigens
24 : DEMONSTRATION OF CELL WALL Plasmolysis Microdissection Raection with specific antibody Electron microscopy Indirect methods- grams staining & acid fast staining, fluroscent staining for acid fast bacteria
25 : DEMONSTRATION OF CELL WALL
26 : GRAMS STAINING MECHANISM- permiability of bacterial cell wall integrity of cell wall METHOD- to a heat fixed smear add crystal violet-1min grams iodine-1 min acetone-2-3sec saffranin- 1min
27 : CONTD… MODIFICATIONS- Kopeloff and Beerman’s method for films & sections, Jensons, Preston & Morrel, quick gram, multiple slide Gram positive- violet Gram negative- pink
28 : GRAMS STAINING PROCEDURE
29 : ZIEHL NEELSON METHOD OF ACID FAST STAINING PRINCIPLE- mycolic acid, lipds, fatty acids& higher alchols integrity of the cell wall METHOD- to a heat fixed smear add carbol fuschin- 5-7min and apply gentle heat 20% sulphuric acid- 2-3sec methylene blue 1-2min
30 : CONTD… MODIFICATIONS- cold method, 5%sulphuric acid Bacilli- stain pink
31 : DIFFERENCE BETWEEN GM+VE &GM-VE CELLS
32 : CELL WALL DEFICIENT FORMS MYCOPLASMA- stable oval or round forms L- FORMS- observed in streptobacillus monoliformis. Induced by penicillin PROTOPLASTS- gram positive bacteria when placed in hypertonic saline SPHEROPLASTS- gram negative bacteria when subjected to penicillin. Some cell wall material is retained PLEIOMORPHIC & INVOLUTION FORMS- swollen & aberrant forms resulting from ageing
33 : CELL MEMBRANE 5-10nm thick elastic membrane beneath the cell wall separating it from cytoplasm Composed of lipoprotein. Sterols absent except in mycoplasma Permeases- membrane associated carrier proteins FUNCTIONS- selective permiability and transport of solutes electron transport and oxidative phosphorylation excretion bearing the enzymes and carrier molecules for biosynthesis
34 : BACTERIAL CELL MEMBRANE
35 : CYTOPLASM Colloid of organic and inorganic solutes in viscous watery solution RIBOSOMES- centres of protein synmthesis. Composed of rRNA of size 10 - 20nm with a sedimentation constant of 70S MESOSOMES- vesicular, convoluted invaginations from plasma membrane. more prominent in GPB principal site of respiratory enzyme site of synthesis of cross wall septa during binary fission
36 : INCLUSIONS VOLUTIN- ( BABES ERNST GRANULES) highly refractile, strongly basophilic bodies consisting of polymetaphosphate. stained by Albert or Neisser stain present in diphtheria bacilli reserve of energy POLYSACCHARIDE- stained with iodine LIPIDS- stained with sudan black VACUOLES- fluid filled cavities covered by a membrane
37 : NUCLEUS Contains the cell’s genome made of a single molecule of double stranded DNA arranged in the form of a circle . Measure about 1mm
38 : PLASMIDS or EPISOMES Extranuclear genetic material Transmitted to daughter cells either by binary fission or from one bacterium to another by conjugation Confer properties like toxigenicity and drug resistance
39 : TRANSPOSONS Segments of DNA that can move around to different positions in the genome of a single cell. Responsible for mutations Types- ClassII- DNA segment gets transferred ClassI- DNA converts to RNA and gets transferred Bacterial transposons are proteins imparting antibiotic resistance when incorporated into a plasmid
40 : TRANSPOSONS Tn5
41 : DEMONSTRATION OF NUCLEUS - acid or ribonuclease hydrolysis and subsequent staining of nuclear material by Feulgen stain specific for DNA appear as oval or elongated bodies
42 : FUNCTIONS OF NUCLEUS Binary fission conjugation
43 : SLIME LAYER & CAPSULE Amorphous viscid bacterial secretion surrounding the cell wall Loose undemarcated secretion – slime layer or glycocalyx Sharply defined structure- capsule
44 : COMPOSITION OF CAPSULE Homo or hetero Polysaccharides made of hexose and pentose sugars plus ribitol, glycerol and other sugar alchohols synthesised by the cell membrane with enzymes- glucosyl and fructosyl transferases producing an insoluble glucan matrix Anthrax bacilli- polypeptide
45 : CAPSULAR FEATURES OF VARIOUS ORGANISMS leuconostoc & klebsiella– slime layer pneumococcus- capsule meningococcus- microcapsule streptococcus salivarious- capsule & slime layer
46 : FUNCTIONS OF CAPSULE enhances virulence protective covering increases invasiveness adhesion capsular antigen for identification of bacteria
47 : DEMONSTRATION OF CAPSULE Negative staining- india ink or nigrosin- capsule appears as a clear halo around the cell Positive staining- Welch method- hot crystal violet followed by rinsing with copper sulphate. Cell background appears dark blue and capsule much paler blue Modifications- Anthony’s , Hiss
48 : CONTD… Manevals method- background- congo red stain- Manevals solution capsule- unstained halo MACROSCOPY- encapsulated- smooth colonies unencapsulated- rough colonies
49 : CONTD… Serological methods- Quellung test- loopful of pneumococci + antiserum( antipneumococcal rabit sera) observe in oil immersion under phase contrast microscope capsules become refractile & visible , seperated from the coccal bodies by the width of the capsule
50 : DEMONSTRATION OF CAPSULE
51 : APPENDAGES
52 : FLAGELLA Long, filamentous appendages arising at the cytoplasmic membrane, protruding through the cell wall into the surrounding medium
53 : ARRANGEMENT OF FLAGELLA monotrichous- single polar flagella amphitrichous- single flagellum at both the poles lophotrichous- tuft of flagella at one or both the ends peritrichous- flagella all around the cell
54 : FLAGELLAR ARRANGEMENT
55 : MORPHOLOGY OF FLAGELLA SIZE- 5-20µm long, width-13-17nm PARTS- FILAMENT- made of flagellin semirigid, forms a left handed helix and exits the cell HOOK- Acts as a sleeve from which the filament emerges transmits rotatory motion from basal body to filament BASAL BODY- consists of M,S,P,L rings connected by a rod shaped structure in gram positive bacteria only 2 rings are seen
56 : FLAGELLAR STRUCTURE
57 : ANTIGENIC PROPERTY PHASE VARIATION- 2 types of flagella due to expression of genes coding for 2 different flagellin proteins in the same bacteria flagellar antigen- H-antigen Endoflagellum- arises from one pole, wraps around the cell body interior to the cell. Eg:- vibro, spirochaetes
58 : FUNCTIONS flagellar antigen H used for identification MOTILITY- impart spinning movement driven by the flow of protons into the cell down the gradient produced by the primary proton pump CHEMOTAXIS, AEROTAXIS, PHOTOTAXIS, ELECTRON ACCEPTOR TAXIS- movement of the cell towards the source of attracant by swimming, tumbling and reorienting itself to the attractant
59 : DEMONSTRATION DIRECT METHOD- dark field microscopy & electron microscopy Staining- Leifson method- basic fuschin- primary stain, tannic acid- mordant methylene blue- counter stain flagella stains as red to blue black Ryu method- solution I- phenol, tannic acid, saturated aluminium potassium sulphate 12 hydrate crystals
60 : DIRECT METHODS
61 : CONTD… Solution II- saturated solution of crystal violet Mix 10 parts of sol I & 1 part of sol II Stain for 1-5 min. Flagella & cell bodies stain violet IMPREGNATION METHODS- silver
62 : CONTD… INDIRECT METHODS- Swarming growth of proteus craiges tube method- spreading of bacteria on semi solid agar hanging drop preparation-motilty of the bacterium examined on a wet film under high power mannitol motility medium- fanning wet mount preparation
63 : INDIRECT METHODS
64 : FIMBRIAE OR PILI Hair like appendages protruding from the cell as straight filaments Found in many gram positive and some gram negative bacteria SIZE- 0.1-1.0µm length, 10nm thick. Each cell possesses 100-500 fimbriae
65 : CONTD… ARRANGEMENT- peritrichous & helically arranged Possess antigenic property Composed of a protein fimbrillin(pilin) which form hollow tubes in the cell membrane ADHESINS- minor proteins on the tips of pili responsible for attachment.
66 : TYPES Common pili- six types- I- responsible for adhesion and are mannose sensitive type II- mannose resistant Sex or fertility pili- long pili present in male bacteria of size 18-20 nm & are 1-4 in number. Helps in forming conjugation tubes for transferring genetic material to female cells Col I ( colicin ) pili
67 : MOTILITY TWITCHING- motility established by pili. Bacterium moves in the direction of the adhering tip resulting in surface motility. Seen because the pili donot rotate & lack a basal body
68 : FUNCTIONS adhesion antigenic property inhibiting phagocytosis transfer of genetic material
69 : DEMONSTRATION Electron microscopy Haemagglutination- tile test- drop of dense bacillary deposit + red cell suspension on a white tile at 3-5ºC . develops coarse clumping within a few seconds mannose 0.5% inhibits type I fimbrial haemagglutination RBC’s of guinea pigs, fowl, horses & pigs agglutinate strongly, sheep and human blood weakly and ox blood scarcely
70 : DEMONSTRATION OF PILI
71 : SPORES
72 : CHARACTERISTICS Spherical or oval structures formed within the bacterial cell Represents the resting or dormant phase formed under unfavourable conditions related to depletion of exogenous nutrients Also called as endospores In sporulation each vegetative cell forms only one spore and during subsequent germination each spore gives rise to only one vegetative bacterium Bacillus and clostridia species form spores
73 : MORPHOLOGY CORE- it’s the spore protoplast. Contains nucleus, protein synthesizing apparatus, energy generating system based on glycolysis. Vegetative cell enzymes are increased in amount Contains large amounts of calcium dipicolinate responsible for resistance SPORE WALL- innermost layer surrounding the inner spore membrane. Made of peptidoglycan and forms cell wall CORTEX- Thickest layer made of peptidoglycan sensitive to lysozyme. Role in spore germination
74 : CONTD… COAT- keratin like protein containing many intermolecular disulphide bonds. Impermeable and provides resistance to antibacterial agents EXOSPORIUM- composed of lipids, proteins and carbohydrates. Consists of paracrystalline basal layer and hair like outer region
75 : CROSS SECTION OF A SPORE
76 : SPORULATION Process by which spores are formed. Involves production of many new structures , enzymes and metabolites along with disappearance of many vegetative cell components -differentiation Spore composition determining genes are activated by association of RNA polymerase core protein with sigma factor Sporulation process takes about 7hrs under laboratory conditions
77 : STAGES OF SPORULATION & GERMINATION
78 : STAGES OF GERMINATION ACTIVATION- spore coat gets damaged INITIATION- triggered by L-alanine or adenosine. Autolysin is secreted that degrades the cortex peptidoglycan. Water is taken up releasing calcium dipicolinate and degrades various spore components by hydrolytic enzymes OUTGROWTH- degradation of cortex and outer layers results in emergence of new vegetative cell
79 : SHAPE &POSITON OF SPORES NON BULGING- diameter of the spore is same as or less than the width of bacteria BULGING- diameter is wider than the bacillary body POSITION- central subterminal terminal
80 : DEMONSTRATION GRAMS STAIN- spore appears as clear unstained ares within the cell ZIEHL NEELSON METHOD- 0.25% sulphuric acid is used. Stain red &bacilli blue MALACHITE GREEN STAIN-5% aqueous solution of malachite green- 1min saffranin or basic fuschin – 30sec spores- stain green& bacilli red
81 : DEMONSTRATION OF SPORES
82 : THANK YOU

 

Add as Friend By : krithikaa sekar
Added On : 1 Years ago.
PowerPoint Presentation on morphology of bacteria
Views 971 | Favourite 0 | Total Upload :1

Embed Code:

Flag as inappropriate


Related  Most Viewed



Free Powerpoint Templates



 



Medical PowerPoint Templates | Powerpoint Templates | Tags | Contact | About Us | Privacy | FAQ | Blog

© Slideworld