Microscopy, Cell Structure and 5 Groups of Microbes

8/9/2019 Microscopy, Cell Structure and 5 Groups of Microbes

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Chapter


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Connects theeyepiece to the

objective lenses

d to reflect light

anexternal light

urceup throug

10X or 15X power.

Supports the tubeandc

to thebase


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nsist of 4X, 10X, 40X and 100X powers.

itha 10X (most common) eyepiece lens,magnifications40X (4X times 10X), 100X , 400X and 1000X.

O - shortest lens- longest one with the greatest power.

nsesarecolorcodedand ifbuilt to DIN standardsarerchangeablebetweenmicroscopes.

hehighpowerobjective lensesare retractable(i.e. 40Xey hit aslide, theendof the lens will push in(spring lo

reby protecting the lensand theslide.

0

0X powers. epiece lens,magnifications

400X and 1000X.

atest power.

built to DIN standardsarescopes.

esare retractable(i.e. 40Xlens will push in(spring lo

theslide.


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Rack Stop:

- anadjustment that determineshow close

theobjective lenscan get to theslide.

- only need toadjust if youareusing very

thinslidesand you weren't able to focusonthespecimenat highpower.

etermineshow close

get to theslide.

youareusing very

ren't able to focusonpower.


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n enser ens:purposeto focus the light onto the specimen.

most useful at thehighest powers(400X andabov

phragm or Iris:

most microscopes havea rotating diskunder thtage.

thisdiaphragmhasdifferent sizedholesand isuso vary the intensity and size of the cone of lighhat is projected upward into the slide.

ht onto the specimen.

t powers(400X andabov

a rotating diskunder th

ent sizedholesand isussize of the cone of lighinto the slide.


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Bright-fieldmicroscopy

Most common

Visible light

Maxmagnification is

about 1,000xPhasecontrast

Usehigh-contrast

objectives

Bright-fieldmicroscopy

Most common

Visible light

Maxmagnification is

about 1,000xPhasecontrast

Usehigh-contrast

objectives

D k fi ld


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Dark-fieldx side illuminationx darkbackground, light specimen

Fluorescencemicroscopex Requiresstaining ofspecimen with

fluorescent dyex Highermagnification thanbright field

Confocal scanning lasermicroscopex Computercontrolledx Laser light sourcex Fluorescentx Cansequentially imagemultipleplanes

ofasampleandprovide D images

ith

field

planeses


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transmission(TEM)

scanning (SEM)


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` Stains All stainsmust haveoneormoredyes

x Basicdyeshaveapositivecharge

x Acidicdyeshaveanegativecharge

Most stainsareperformedon glassslides

` Simplestains

Usually useabasicdye that providescolorandcontrast toacolorlessmicrobe

` Stains All stainsmust haveoneormoredyes

x Basicdyeshaveapositivecharge

x Acidicdyeshaveanegativecharge

Most stainsareperformedon glassslides

` Simplestains

Usually useabasicdye that providescolorandcontrast toacolorlessmicrobe


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m cro es Gramstain separatesbacteria intoGrampositi

(purple) ornegative( red)

x Primary stain iscrystal violet (purple)x Secondary stain issafranin (reddye)

sbacteria intoGrampositi

red)

al violet (purple) franin (reddye)


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ono rea y s a n w ram ss a nThebacterial cellsare flooded withcarbol fuchsin (red) anheat isapplied

Thecellsare rinsed withacidalcohol, which removescarfuchsin fromcells that arenot acid-fast

Methyleneblue isusedasacounterstain

ram ss a nd withcarbol fuchsin (red) an

alcohol, which removescart acid-fast

counterstain

s r c res


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s ruc ures Malachite green isused tostainendospores

India ink isused tostaincapsularbacteria

d tostainendospores

incapsularbacteria


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` Fluorescent dyes

DNA-binding dyes

x acridine orangex ethidium bromide

Immunofluorescence reliesuponafluorescently-labeledantibody specific toa

cellularcomponent

liesuponantibody specific toa


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a. Bacteria

b. fungi: yeasts

and molds

c. Viruses

d. protozoa

e. algae

a. Bacteria

b. fungi: yeasts

and molds

c. Viruses

d. protozoa

e. algae


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ria are typically

llular,

scopic,

ryoticorganismseproduceby

fission


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` Note gram-positive(purple) cocciclusters.

m-positive(purple) cocci.


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Yeasts are typicallyunicellular,microscopic,eukaryotic fungi thatreproduceasexually bybudding

` Molds are typicallyfilamentous,eukarfungi that reproducproducing asexualreproductivespore


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Saccharomyces cerevisiae

Note budding yeast (arrows).

Wine yeast withbudandbudscars(Sacchr

spp.).

Magnification:-- x2,270--(Basedonan image

inch in thenarrow dimension)

Wine yeast withbudandbudscars(Sacchr

spp.).

Magnification:-- x2,270--(Basedonan image

inch in thenarrow dimension)


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ly submicroscopic,ar infectiousparticlesnonly replicatea living host cell.

st majority of virusesseither DNAor RNA

t both.

Transmission Electron Microgra

Adenovirus


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pically

llular,

scopic,

ryotic

isms that lack

l wallPhotomicrograph ofAmoeb

proteus

Note the numerous pseudopodi


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pically eukaryotic

organisms that

out photosynthesis


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` ree oma n ys em y oese e am

y oese e a


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` ree oma n ys em y oese e a isanevolutionary model ofclassificationbased

x differences in1. the sequences of nucleotides in the cell's ribos

RNAs (rRNA)

2. the cell's membrane lipid structure

3. its sensitivity to antibiotics.

m y oese e a del ofclassificationbased

f nucleotides in the cell's ribos

ane lipid structure

antibiotics.

`


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different cell types,each representing adomain.

` The threedomainsare

theArchaea (archaebacteria), theBacteria (eubacteria),and theEukarya (eukaryotes).

x 4 kingdoms:x Protistsx FungixAnimaliax Plantae

h representing adomain.

bacteria),ria),andtes).


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Archaea possess the

llowing characteristics:

rokaryotic cells

havemembranescomposedofbranched hydrocarbonchains attached toglycerol by ether linkages

Archaea possess the

llowing characteristics:

rokaryotic cells

havemembranescomposedofbranched hydrocarbonchains attached toglycerol by ether linkages

`


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.

` Not sensitive tosomeantibiotics that affect theBabut aresensitive tosomeantibiotics that affect theEukarya.

` Contain rRNA that is unique to theArchaea as iby thepresencemolecular regionsdistinctly differthe rRNAofBacteria andEukarya.

` Live inextremeenvironmentsand includemethan

extremehalophiles,andhyperthermophiles.

.

antibiotics that affect theBa omeantibiotics that affect the

unique to theArchaea as i cular regionsdistinctly differ

andEukarya.

onmentsand includemethan

ndhyperthermophiles.


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cteria possess the following characteristics:teria areprokaryotic cells.

theEukarya, they havemembranescomposedofunbranchedacid chains attached to glycerol by ester linkages

wallscontain peptidoglycan.

itive to traditional antibacterial antibioticsbut are resistant tot antibiotics that affect Eukarya.

ain rRNA that is unique to the Bacteria as indicatedby the

encemolecular regionsdistinctly different from the rRNA ofaea andEukarya.

mplesaremycoplasmas,cyanobacteria,Gram-positivebacteriaGram-negativebacteria.

cteria possess the following characteristics:teria areprokaryotic cells.

theEukarya, they havemembranescomposedofunbranchedacid chains attached to glycerol by ester linkages

wallscontain peptidoglycan.

itive to traditional antibacterial antibioticsbut are resistant tot antibiotics that affect Eukarya.

ain rRNA that is unique to the Bacteria as indicatedby the

encemolecular regionsdistinctly different from the rRNA ofaea andEukarya.

mplesaremycoplasmas,cyanobacteria,Gram-positivebacteriaGram-negativebacteria.


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` possess the following characteristics:

` Eukarya haveeukaryotic cells.

` Like theBacteria, they havemembranescomposedofunbrafatty acid chains attached to glycerol by ester linkages

` cell wall contains no peptidoglycan.` resistant to traditional antibacterial antibioticsbut aresensitiv

antibiotics that affect eukaryoticcells.

` contain rRNA that is unique to the Eukarya as indicatedbypresencemolecular regionsdistinctly different from the rRNAArchaea andBacteria.

` possess the following characteristics:

` Eukarya haveeukaryotic cells.

` Like theBacteria, they havemembranescomposedofunbrafatty acid chains attached to glycerol by ester linkages

` cell wall contains no peptidoglycan.` resistant to traditional antibacterial antibioticsbut aresensitiv

antibiotics that affect eukaryoticcells.

` contain rRNA that is unique to the Eukarya as indicatedbypresencemolecular regionsdistinctly different from the rRNAArchaea andBacteria.


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,otic organisms


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,oticorganisms.

ples includesslimemolds,oids,algae,andprotozoans.

ingdomllularormulticellularorganismskaryoticcell types.

avecell wallsbut arenot

ed into tissues.t carry out photosynthesisandnutrients throughabsorption.

ples includesac fungi,clubeasts,andmolds.

cells.cells.


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-cellsareorganized into tissuesandhavewalls.

- obtainnutrientsby photosynthesisandabsorption.

-Examples includemosses, ferns,conifers,flowering plants.

d. Animalia Kingdom- multicellularorganismscomposedofeuk

cells.

- cellsareorganized into tissuesand lackwalls.

- donot carry out photosynthesisandobtainutrientsprimarily by ingestion.

-Examples includesponges, worms, insectvertebrates.

-cellsareorganized into tissuesandhavewalls.

- obtainnutrientsby photosynthesisandabsorption.

-Examples includemosses, ferns,conifers,flowering plants.

nimalia Kingdom- multicellularorganismscomposedofeuk

cells.

- cellsareorganized into tissuesand lackwalls.

- donot carry out photosynthesisandobtainutrientsprimarily by ingestion.

-Examples includesponges, worms, insectvertebrates.


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a. prokaryotic.

b. single-celled,microscopicorganisms

Exceptions - visible to thenakedeye

- Epulopiscium fishelsoni - abacillus, 80 (diameterand 200-600 m long

- Thiomargarita namibiensis - asperical bbetween 100 and 750 m indiameter.

a. prokaryotic.

b. single-celled,microscopicorganisms

Exceptions - visible to thenakedeye

- Epulopiscium fishelsoni - abacillus, 80 (diameterand 200-600 m long

- Thiomargarita namibiensis - asperical bbetween 100 and 750 m indiameter.


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generally much

mallerthanukaryoticcells.

very complexespite theirsmallize. Bacteria on a Human Epithelial

Cell from the Mouth

The bacteria are the small dark purpl

dots and dashes on the light blue cell

The oval purple mass in the center is

nucleus of the epithelial cell.


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` three basic shapes:

Coccus

rodorbacillus

spiral

:


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spherical oroval

acteria

having oneofseveral

istinct arrangements

asedon theirplanesof

ivision.


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lococcus -cocci arranged in

rs

lococcus -cocci arranged in

rs


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tococcus:cocci arranged inchainstococcus:cocci arranged inchains


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d:cocci arrangedaresof 4

ement:

Stain


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lococcus:cocci arranged in irregular,often-likeclusterslococcus:cocci arranged in irregular,often

-likeclusters


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` Electron Micrograph ofMethicillin-Resistant Staphyaureus (MRSA)

h ofMethicillin-Resistant Staphy


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hapedbacteria.

ide inoneplanecing abacillus,tobacillus,orobacillus

gement.


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micrographofabacillus Scanning Electron MicrogrPseudomonas aerugino


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` Escherichia coliO157H7 isastrcoliproducesashiga-like toxin tepithelial cellsof the large intesticausing hemorrhagiccolitis,abl

diarrhea.

` In rarecases, theshiga-toxinenbloodand iscarried to thekidneusually inchildren, it damages vcellsandcauseshemolyticuremsyndrome. Notedividing bacilli.


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c. acoccobacillus:

oval andsimilar toacoc

cillus:

imilar toacoc


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helical orcorkscrew-shapedbacterium.

piralscome inoneof three forms:avibrioaspirillum

aspirochete.

dbacterium.

orms:


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appearsasacurvedbacillus

s).

Vibrio cholerae - Gram-negative,

facultatively anaerobic,curved(vib

shaped), rodprokaryote;causesAcholera.

Vibrio cholerae - Gram-negative,

facultatively anaerobic,curved(vib

shaped), rodprokaryote;causesAcholera.


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rocheteBorrelia (arrows) ina

mear.

Scanning Electron Micrograph ofL

interrogans


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` a typical bacteriumusually consistsof:

` acytoplasmicmembranesurroundedby apeptidoglcell wall andmaybeanoutermembrane;

` a fluidcytoplasmcontaining anuclear region(nuclenumerous ribosomes;and

` often variousexternal structuressuchasa glycocal

flagella,andpili.

` a typical bacteriumusually consistsof:

` acytoplasmicmembranesurroundedby apeptidoglcell wall andmaybeanoutermembrane;

` a fluidcytoplasmcontaining anuclear region(nuclenumerous ribosomes;and

` often variousexternal structuressuchasa glycocal

flagella,andpili.


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` Cytoplasmic Membrane

` Nucleus

` Cytopl

asm

` Cytoplasmic Membrane

` Nucleus

` Cytopl

asm


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` http://www.microbelibrary.org/microbelib

es/ccImages/Articleimages/Spencer/sp

cellwall.html

` http://www.microbelibrary.org/microbelib

es/ccImages/Articleimages/Spencer/sp

cellwall.html


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Shapes

Spherical - coccus (pl.,cocci)

Cylindrical - rod

x very short - coccobacillus

x curved - vibrio

x short spiral - spirillum

x long spiral - spirochete

Shapes

Spherical - coccus (pl.,cocci)

Cylindrical - rod

x very short - coccobacillus

x curved - vibrio

x short spiral - spirillum

x long spiral - spirochete


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Microscopy, Cell Structure and 5 Groups of Microbes

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