Lab #5 The Microscope

Getting to know the microscope

Field of View micrometer/ruler slide measurement of field of view (FOV) allows you to “guess” as to the size of an object or sample in it FOV decreases as the magnification increases size of the organism/cell = FOV x fraction of FOV taken up by organism/cell FOV = 5.5 mm

Gram positive bacteria: rival proteobacteria in diversity – 2 major subgroups based on cell shape: cocci and bacillus – most decompose organic matter in soil – two strains of Actinomycetes cause leprosy and tuberculosis – Streptomyces used by pharmaceutical companies to produce antibiotics – numerous strains are very pathogenic: Bacillus anthracis, Clostridium botulinum, Staphylococcus and Streptococcus Some Bacterial Groups GRAM-POSITIVE BACTERIA 5 µm Streptomyces Mycoplasmas covering a human fibroblast cell

Spirochetes – move through rotation provided by internal flagella-like filaments – Treponema pallidum – causes syphilis – Borrelia burgdorferi – causes Lyme disease – Leptospira – causes leptospirosis (field fever) Some Bacterial Groups 5 µm SPIROCHETES Leptospira

Cyanobacteria – photoautotrophs – only prokaryotes with plant-like, oxygen-generating photosynthesis – abundant components of fresh water and marine phytoplankton Some Bacterial Groups CYANOBACTERIA Oscillatoria 50 µm

Spirochete/Spiral Bacteria Treponema pallidum – one of the treponeme bacteria causes syphillis

Cocci bacteria Neisseria gonorrhea – causes gonorrhea – gram negative

Bacillus bacteria Mycobacterium tuberculosis – causes tuberculosis – gram negative – other mycobacteria family members are gram +ve

Nostoc cyanobacteria or blue green bacteria colonial form of multiple cells living as a filamentous colony – two cell types – 1. photosynthetic – produces O2 as a by-product – 2. non-photosynthetic/heterocyst – fixes nitrogen from the environment heterocyst

Anabaena cyanobacteria or blue green bacteria colonial form of multiple cells living as a filamentous colony – three cell types – 1. photosynthetic vegetative cells – produce O2 as a by- product – 2. non- photosynthetic/heterocysts – fix nitrogen from the environment – 3. very large akinetes – for the creation of a new colony heterocyst akinete photosynthetic cell