Transcript Gram stain
Ch 4 - Microscopy & Identification Relative Sizes What other kind of metric measurements will you do? Volume - liter (dl, ml, l) what is the equivalent of 1 cc? Mass - grams (mg, g) To get a sense of scale, look for “powers of ten” on the Web http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/ van Leuwenhoek’s simple microscope early compound microscope Light microscope See 4.7 for how it works Fluorescent With dye with dye-antibodies Phase-contrast Creates very thin “slices” by using precise laser lighting & computer-processing Confocal Transmission electron microscope (TEM) Scanning electron microscope (SEM) (images are colorized) STEM: Rec A protein AFM: toxin from C. perfringens credit card hologram surface ScannedProbe Microscopy CD surface Wet mount, no stain Hanging drop: for living, moving microbes Preparing a smear Use a basic/ alkaline dye (chromophore is positively charged) Simple stain (crystal violet) Negative stain Use an acid dye (chromophore is negatively charged) Differential stains Gram stain - the most important one to know Mycobacterium or Nocardia Acid-fast stain Endospore stain Just capsule stain Capsule stain with counterstain flagellar stain Other prokaryotic internal structures (inclusions) lipid “Bt” toxin carboxysomes sulfur magnetite Air bubbles & dirt Basic Methods 1. collect (see also App. B) 2. amplify 3. inspect 4. identify Bacterial colonies Biochemical tests Serological tests (Bacterio)phage typing DNA-based tests %G+C (%GC) hybridization-based “fingerprinting” (restriction fragment polymorphisms) sequence-based Dichotomous key (animated description at The Microbiology Place) taxonomy phylogeny How many kingdoms of life? Two Prokaryota Eukarya vs. Three Bacteria Archaea Eukarya vs. Five Monera (bacteria) Protista Plants Fungi Animals vs. Six Kingdoms Bacteria Archaea Protista Plants Fungi Animals Modern Linnaean Taxonomy (largely based on his ideas) Domain (2 mnemonics) How are organisms actually named? binomial nomenclature (invented by Gaspard Bauhin and Johann Bauhin; Linnaeus (1753) was the first to “popularize”) species name = genus name + specific epithet eg: Staphylococcus aureus OR Staphylococcus aureus Capitalized lower case eg: Homo sapiens “A species of” = genus name + sp. eg: Staphylococcus sp. “several species of” = genus name + spp. eg: Homo spp. Note: Usually can’t say S. aureus or H. sapiens, etc. without 1st using entire name