Be able to convert distances between nanometers nm micrometers um and millimeters mm you can use a calculator for this but it must not be an app in your phone It must be a calculator that does not have networking capability 1 millimeter 10 3 m 1 micrometer 10 6 m micron um 1 nanometer nm 10 9m 1 Angstrom 10 10 m 1 picometer 10 12 m Koch s Postulates Infectious Agent X must meet 4 criteria 1 Agent X must be always present in host s with disease Y and absent in those that do not have disease Y 2 Must be able to isolate a pure culture of agent X 3 4 Agent X can now be re isolated from this new diseased host Introduction of agent X into a new host induces disease Know what Pasteur disproved Pasteur disproved spontaneous generation for microbes Spontaneous generation a hypothesis that living organisms arise from nonliving matter Pasteur also showed that microbes are responsible for fermentation Pasteurization the application of a high heat for a short time Know the details of the discovery of penicillin Alexander Fleming discovered this first naturally occurring antibiotic in 1928 The observed that Penicillium fungus made an antibiotic Penicillin that killed Staphylococcus aureus Know the causes of the emerging infectious diseases we covered in Lecture 2 and know the background we discussed on these infectious agents Emerging infectious diseases EIDs new diseases and diseases increasing in incidence Spanish Flu 1918 caused by Influenza Virus Viral Avian Flu Influenza A virus Severe Acute Respiratory Syndrome SARS associated Coronavirus 2002 2003 MERS is also Coronavirus This is mostly from animal transmission Camels particularly Ebola hemorrhagic fever Ebola Virus Major outbreak in 2 years Liberia Guinea Sierra Leone 1 West Nile Causes encephalitis appeared in NYC in 1999 spread my nonmigratory birds Aids Caused by HIV 2011 had 34 million people living with AIDS and 35 million have died HAART therapy saves lives of AIDS pts Mad cow disease prion a misfolded protein causes other proteins to misfold by contact Also causes Creutzfeldt Jakob diease CJD Prion Bacterial Escherichia Coli O157 H7 A strain of EHEC that is a toxin producing strain and can be spread in contaminated meat Animals serve as a reservoir Watch out for neural tissue contamination Invasive Group A Streptococcus Streptococcus pyogenes causes Scarlet fever strep throat and Necrotizing fasciitis this is very serious and invades skin and causes tissue damage Clostridium difficile A resistant spore that takes over a patients normal intestinal bacteria flora This is often fatal Methicillin resistant Staphylococcus aureus MRSA acquired resistance to multiple antibiotics Overuse of antibiotics selects for antibiotic resistant strains Protozoal Cryptosporidiosis Cryptosporidium protozoan this is commonly transmitted via contaminated water and food Common cause of diarrheal illness in developing countries This infects the healthy and immunocompromised Know the composition of an E coli cell by weight for the major classes of macromolecules we discussed Water 70 Proteins 15 Know the approximate size range of bacteria viruses etc and which types of microscopy are useful for each Bacteria 5 um 10 um in length very few bacteria will be larger than a RBC Darkfield used to observe living unstained preparations and produces a bright image of the object against a dark background too thin to be seen by brightfield but the light scatter that they produce can be seen o Used to identify Spirochetes like Treponema pallidum a causative agent of syphilis Phase Contrast Microscopy observe living cells by accentuating diffraction of light passing through a specimen from that of water o Used to identify endospores and inclusion bodies with refractive indexes different o This is good for viewing materials of differing density i e nucleus and mitochondria Refract differently so we can easily pick them out Differential Interference Contrast Microscopy accentuates diffraction of light that passes through a specimen uses TWO beams of light o VERY good for EUKARYOTIC microbes and large bacterial cells Fluorescence Microscopy uses UV to fluorescent spectrum of light fluorescence is 2 excited by one wavelength of light and emits a longer wavelength of lower energy Must be stained cells o GFP Confocal Microscope produces 3 D image by using a laser light with precise wavelength emissions to excite fluorochrome o Good for microbes and allows us to scan the cell and look at thicker samples Two Photon Microscopy Two photons of long wavelength light excite the dye o used to study cells attached to a surface up to 1mm deep SAM measures sound waves that are reflected back from an object o Bacterial biofilm Electron Microscopy requires fixed specimens formaldehyde is used and uses electrons instead of light This shorter wavelength increases resolution Resolution is about 2nm 200 000 x o Good for viruses and large molecules TEM vs SEM o TEM used for ultrathin sections of a specimen and electrons pass through it Lenses are for focusing electrons are magnets instead of glass prisms we would use for focusing light We can add color later 10 000 100 000x 2 5nm o SEM electron gun produces a beam of electrons that scans the surgace of a whole specimen 3D surface structures We cant partition or cut this so we cant see as well as we would with TEM 1 000 10 000x 20nm Scanned Probe Microscopy Uses metal probe to scan feel along a specimen 1 100 of an atom Be able to define magnification resolution diffraction Magnification Objective L x Ocular L Resolution the ability to distinguish two points a given distance apart Diffraction bending of light around an obstacle i e a microscope light and a specimen Know the major types of macromolecules we discussed in Lecture 3 Lipids primary in cell membranes insoluble in H2O Saturated no double bounds Unsaturated one or more double bonds Protein essential to cell structure and function Secondary structure amino acid chain folds in a regular helix plane Primary polypeptide chain Tertiary helix irregularly folds disulfide bonds hydrogen bonds Quaternary two or more polypeptides Nucleic Acids mononucleotides and nucleic acids 3 Consist of a pentose sugar and a phosphate group nitrogen containing base Know the differences between Gram negative bacteria and Gram positive bacteria How are their structures different Gram negative Pink stain Thin peptidoglycan Outer and inner membrane Periplasm LPS endotoxin NO teichoic acids Gram positive
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