Light Microscopy Handout PDF
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This document provides an overview of light microscopy, including descriptions of mechanical, optical, and illuminating parts. It also covers topics such as the function of objectives and eyepieces, calculating total magnification, numerical aperture, and distinguishing between useful and empty magnification.
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http://www.smsoptical.com/Accessories%20Images/M5-nosepiece-250.jpg MAIN PARTS OF LIGHT MICROSCOPE https://www.olympus-lifescience.com/en/ 1) MECHANICAL PART 2) OPTICAL PART 3) ILLUMINATING PART MECHANICAL PART Stand Arm Head (body tube) Micr...
http://www.smsoptical.com/Accessories%20Images/M5-nosepiece-250.jpg MAIN PARTS OF LIGHT MICROSCOPE https://www.olympus-lifescience.com/en/ 1) MECHANICAL PART 2) OPTICAL PART 3) ILLUMINATING PART MECHANICAL PART Stand Arm Head (body tube) Micro- and macroscrew Stage https://cemeq.ufg.br/n/97536-o-fabuloso-microscopio Revolving nosepiece with objectives Screws for moving the stage, condenser and screw for light regulation Switch https://cemeq.ufg.br/n/97536-o-fabuloso-microscopio OPTICAL & ILLUMINATING PART OPTICAL PART: Eyepiece (ocular lens) Objective https://cemeq.ufg.br/n/97536-o-fabuloso-microscopio ILLUMINATING PART: Illuminating source Condenser FUNCTION OF THE OBJECTIVE & THE EYEPIECE OBJECTIVE: → the most important and the most complex part of microscope → it DISTINGUISHES DETAILS and CREATES THE IMAGE of subject EYEPIECE: → magnifies the image created by objective → it works as a MAGNIFYING GLASS and makes the image visible for the human eye → for the creating of image, the SET OF EYEPIECE & OBJECTIVE is needed → if the eyepiece is put away, the object is not visible WORKING DISTANCE: → it is the distance at which an objective is able to focus → it is measured from the cover slip to the lens of the objective → the more the objective is magnifying the smaller is the working distance TOTAL MAGNIFICATION OF MICROSCOPE (M) M = Mobj. x Meyep. x Kt Mobj. = magnification of objective Meyep. = magnification of eyepiece Kt = magnifying coefficient of the body tube (head of microscope) (usually = 1) the total magnification is the PRODUCT OF MAGNIFICATION OF INDIVIDUAL LENSES if the objective lens magnifies 100-fold and the eyepiece magnifies 10-fold, the final magnification will be 1000-fold NUMERICAL APERTURE magnification (NA) 10x/0.25 numerical aperture (NA) NA = n x sin α n = THE REFRACTIVE INDEX of the environment between object (specimen) and objective (nair = 1, nimmersion oil = 1.5 (the same as the glass)) α = HALF-ANGLE of the cone of light entering the lens from the specimen objective 10x lens THE BIGGER IS THE VALUE 2α half-angle of the OF NUMERICAL α cone of light entering the lens APERTURE, THE BETTER IS THE RESOLUTION OF THE specimen MICROSCOPE https://micro.magnet.fsu.edu/primer/anatomy/numaperture.html POWER OF RESOLUTION (d) THE ABILITY TO DISTINGUISH TWO VERY CLOSELY POSITIONED OBJECTS IT IS THE MINIMUM DISTANCE BETWEEN TWO DISTINGUISHABLE OBJECTS THE SMALLER IS THE λ VALUE OF d THE d= BETTER IS THE NAobj.+ NAcon. RESOLUTION OF THE MICROSCOPE d: The value of d depends on the numerical aperture of objective (NAobj.) and condenser (NAcon.) and from the wavelength (λ) of incident light The limit of resolution of a light microscope is about 0.2 μm OBJECTIVES 1) DRY OBJECTIVE: NA = n x sin α nair = 1.000727 (1) NA = n x sin α αmax = 90° → sin 90°= 1 NAmax = 1 x 1 = 1 2) OIL-IMMERSION OBJECTIVE: - cedar oil is used as the immersion (n = 1.5) or we can use water (n = 1.3) - numerical aperture of the oil-immersion objective NAmax= 1.3 – 1.5 (better resolution). USEFUL MAGNIFICATION → the value of NA states the RESOLVING POWER of the objective as well as the LIMITS FOR MAGNIFICATION → if the total (final) magnification of the microscope lies at interval from 500 to 1000 multiple of NA, we call this magnification USEFUL MAGNIFICATION → total magnification that is out of this interval is called EMPTY MAGNIFICATION USEFUL MAGNIFICATION: 500 x NAobj. < M < 1000 x NAobj. EMPTY MAGNIFICATION: magnification out of this interval USEFUL MAGNIFICATION https://nanopdf.com/download/optical-aberrations-and-objective-lens_pdf It is possible to Image is more magnified with distinguish the details no corresponding increase in present in an image detail resolution = image degradation USEFUL MAGNIFICATION TASK Calculate the useful magnification, if we use objective 45x with NA = 0.65 and decide if it is right to use eyepiece magnifying 20x. TOTAL MAGNIFICATION: M = 45 x 20 x 1 = 900x USEFUL MAGNIFICATION: 500 x NAobj. < M < 1000 x NAobj. 500 x 0.65 - 1000 x 0.65 325x 650x If we use objective 45x in combination with eyepiece 20x, the total magnification will be 900x (higher than upper limit) = EMPTY MAGNIFICATION The objective must be combined with the eyepiece with a lower value of magnification, for example 10x – the total magnification is 450x and it is inside the interval of USEFUL MAGNIFICATION IMMUNOFLUORESCENCE MICROSCOPE → FLUORESCENT MOLECULES absorb light at one wavelength and emit it at another, longer wavelength → FLUORESCENCE MICROSCOPE is similar to an ordinary light microscope except the illuminating light, from a very powerful source, is passed through two sets of filters 1. FILTER → filters the light before it reaches the specimen, only the wavelengths that excite the particular fluorescent dye can pass 2. FILTER → filters the light obtained from the specimen, it passes only those wavelengths emitted when the dye fluoresces IMMUNOFLUORESCENCE MICROSCOPE Molecular Biology of the Cell, Sixth Edition; ISBN: 9780815344643 IMMUNOFLUORESCENCE MICROSCOPE → immunofluorescence microscopy is most often used to DETECT SPECIFIC PROTEINS OR OTHER MOLECULES in cells and tissues → a widely used technique is to COUPLE FLUORESCENT DYES TO ANTIBODY MOLECULES, which then serve as reagents that bind selectively to the particular macromolecules → 2 commonly used fluorescent dyes: FLUORESCEIN (FITC) (green) RHODAMINE (TRITC) (red) MARKED PRIMARY ANTIBODY endothelial cells https://www.microscopemaster.com /fluorescent-dyes.html https://en.wikipedia.org/wiki/Spindle_apparatus https://commons.wikimedia.org/wiki/File:Yeast_membrane_proteins.jpg mitotic spindle yeasts neuron stromatolite https://www.researchgate.net/figure/Figure-C-4-Kryton-Argon-confocal- https://frontal-cortex.tumblr.com/post/34502613123/fixed-neuron- images-on-fluorescence-in-situ-hybridisation-FISH-on_fig42_267851913 a-multi-wavelength-three ELECTRON MICROSCOPE → the source of illumination is the BEAM OF ELECTRONS → air must be pumped out of the column to create a VACUUM → the electron microscope uses ELECTROSTATIC & ELECTROMAGNETIC LENSES in forming the image → electron microscopes have much greater resolving power than light microscopes and can obtain much higher magnifications of up to 2 million times, while the best light microscopes are limited to magnifications of 2,000 times ELECTRON MICROSCOPE TYPES OF ELECTRON MICROSCOPES: TRANSMISSION ELECTRON MICROSCOPY (TEM): → is principally quite similar to the compound light microscope, by sending an electron beam through a very thin slice of the specimen. SCANNING ELECTRON MICROSCOPY (SEM): → visualizes details on the surfaces of cells and particles and gives a very nice 3D view. Specimen is coated with an ultrathin metal coating (gold, platinum, osmium). SEM images the sample surface by scanning it with a high-energy beam of electrons in a raster scan pattern. thylakoids https://ucmp.berkeley.edu/glossary/gloss3/photosyn/pigments.html GA in plant cell https://www.sciencephoto.com/media/546891/view/golgi-apparatus-tem flagellum fhttps://www.researchgate.net/figure/A-D- Chlamydomonas Electron-micrographs-of-C-reinhardtii-flagella- the atomic structure of a diamond A-and-C-Wild-type-g1-B-and- https://ja.m.wikipedia.org/wiki/%E3%83%95%E3%82%A1%E3%82 https://www.britannica.com/technology/electron-microscope D_fig3_5690895lagellum %A4%E3%83%AB:Chlamydomonas_TEM_04.jpg a section of a cell of Bacillus subtilis https://commons.wikimedia.org/wiki/File:Bacillus_subtilis.jpg transmission electron micrograph of a myelinated axon https://sk.m.wikipedia.org/wiki/S%C3%BAbor:Myelinated_neuron.jpg electron micrograph of an ultra-thin section of a dividing pair of group A streptococci (20,000 x) http://textbookofbacteriology.net/structure_1 an image of a house fly compound eye surface (450x) http://archive.boston.com/bigpicture/2008/11/peering _into_the_micro_world.html an image of a fruit fly's compound eye https://commons.wikimedia.org/wiki/File:Drosophilidae _compound_eye_edit1.jpg https://en.wikipedia.org/wiki/Scanning_electron_microscope#/media/File:Misc_pollen.jpg hematite https://upload.wikimedia.org/wikipedia/commons/9/99/Hematite_in_Scanning_Electron_Microsco pe%2C_magnification_100x.JPG https://commons.wikimedia.org/wiki/File:LT-SEM_snow_crystal_magnification_series-1.jpg Gills of a fish, the mudskipper (Periophthalmus argentilineatus) https://slideplayer.com/slide/14401790/ http://www2.odn.ne.jp/~umisuzume/yaima001/2002/tonton_s ebire.html the fibrous configuration of a dry macrofoam sponge swab snow crystal http://www.publicdomainfiles.com/show_file.php?id=13531896611989 Juglans nigra (Black Walnut tree) lower leaf Lower surface of Arabidopsis thaliana leaf, surface, showing a variety of trichomes showing a trichome http://archive.boston.com/bigpicture/2008/11/peering_into_the_micro_world.html http://archive.boston.com/bigpicture/2008/11/peering_into_the_micro_world.html tobacco seed https://mvac.uwlax.edu/ProcessArch/lab_floral.html close-up of a weevil (Curculionidae family) image of pyralidae moth, side view of head http://archive.boston.com/bigpicture/2008/11/peering_into_the_micro_world.html http://archive.boston.com/bigpicture/2008/11/peering_into_the_micro_world.html close-up of an ant a breast cancer cell http://archive.boston.com/bigpicture/2008/11/peering_into_the_micro_world.html http://archive.boston.com/bigpicture/2008/11/peering_into_the_micro_world.html leukemia cells (left) shown in comparison with bone marrow cells (right) https://pt.slideshare.net/mcasade8/microscopes-7241414 Staphylococcus epidermidis cluster https://owlcation.com/stem/Staphylococcus-epidermidis-Biofilms-and-Antibiotic-Resistance Mite feeding on a mystacocarid https://www.sciencesource.com/Doc/TR7/3/d/1/a/SS2619827.jpg?d63643046111