4 “Cells alive” animation (View this animation to compare the sizes of different objects, animals, and microbes)
5 Light MicroscopesProperties of light limit magnification/resolution to 2000XBrightfield (compound light) microscopeMost commonField of view is bright; specimen is darkerLeast expensiveRequires staining of specimens usuallyStaining requires killing organisms
12 Picture of bacteria taken with a fluorescence microscope
13 Confocal microscopyMeningitis-causing bacteria. The tiny yellow dots are Neisseria meningitidis bacteria living inside human airway cells. Although they live in the noses and throats of many people without leading to disease, if they break through into the bloodstream they can cause potentially fatal meningitis and septicemia.(Confocal image by Shao Jin Ong.)
14 Confocal micrographic image of Bacillus anthracis; cell walls appear green, while the spores appear red.Taken by CDC/ Dr. Sherif Zaki/ Dr. Kathi Tatti/Elizabeth White
15 Electron Microscopes Beware of artifacts Staining techniques require expertise and $$$Dehydration of specimenPlacing specimen under vacuumTransmission electron microscope (TEM)Magnify 10,000-up to 500,000XView sections of organismCan see inside viruses/cellsScanning electron microscope (SEM)Magnify 1,000-10,000XSee 3D image of structure
17 Under a high magnification of 12230x, this scanning electron micrograph (SEM) depicted some of the ultrastructural morphologic features displayed by this group of Gram-positive Micrococcus luteus bacteria. Taken by CDC/ Betsy Crane
18 This negative-stained transmission electron micrograph (TEM) depicts the ultrastructural details of an influenza virus particle, or “virion”. A member of the taxonomic family Orthomyxoviridae, the influenza virus is a single-stranded RNA virus.Taken by CDC/ Dr. Erskine. L. Palmer; Dr. M. L. Martin
19 Scanned-probe microscopes Can “see” moleculesExpensiveUsed in research
20 Scanned-probe microscopy – Figure 3 Scanned-probe microscopy – Figure 3.11(a) is RecA (repair) protein from Escherichia coli and (b) is the O toxin from Clostridium perfringens.
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