Microbiology
Laboratory Practical I
Suggested approach…
• As you review your notes and slides, test yourself,
continually!
– Know the classification of each organism.
– Example:
• Recognize this organism modeled as a mold in the Kingdom: Fungi;
phylum: Zygomycota; genus: Rhizopus
• Know the name of the pertinent structures or
processes and their significance (function).
– Example:
• Zygospore: sexual sporangium of the zygomycetes, including
Rhizopus
– Use this approach on all material!!
• Flagellum: motility appendage of bacteria and some protozoa
• Scanning objective lens: 4X magnification, first in sequence
• Morphological stain: technique used to view size, shape,
arrangements
Compound Light Microscope
• Structure and Function
– Know part name and its
function (when and why we
use it)
• Lens Magnifications
– Know individual power and
total magnifications with
each
• Proper Handling and Use
– Sequence of procedures
used to view specimen
– Proper cleaning and
storage of scopes
Aseptic Techniques
• Appreciate need for proper technique in lab to
prevent contamination
• Know names of tools used and proper handling
• Know various types and forms of culture media
and their applications
– General Purpose medium
• Ex.: Nutrient agar
– Selective medium
• Saboraud’s Dextrose Agar
– High sugar
– Low pH
Culture Media
• Know various types and forms of culture media
and their applications
– Formulations:
• General Purpose medium
– Ex.: Nutrient agar
• Selective medium (selects for what???)
– Ex.: Saboraud’s Dextrose Agar (High sugar, Low pH)
– Media Forms
• Liquid (broth) medium vs. solid (w/ agar) medium
– types include agar deeps, motility deeps, slants, plates, and
broth tubes
– inoculation tools and techniques for each
– Culture characteristics obtainable from each form
• oxygen requirements, motility, colony morphology, etc.
Morphological Staining Techniques
• Simple Stain (use of single stain)
– Basic stain (+) adheres to bacterial cell
wall (-)
• Crystal violet, safranin, methylene blue,
others
• Negative Stain
– Acidic stain (-) adheres to glass slide (+)
• Nigrosin, Congo Red, India ink
– Clear area (cell) contrasts with opaque
background
Structural Stains
• Flagella arrangements on prepared slides
– Polar flagella (amphitrichous)
• Spirillum volutans
– Nonpolar flagella (peritrichous)
• Proteus vulgaris
Eukaryotes
• Fungi—Yeasts and Molds
– Phyla: Zygomycota, Ascomycota,
Basidiomycota
• Protists—Algae* and Protozoa
– Ciliates, Flagellates, Amebas, Apicomplexans
• Animals—Parasitic worms (Helminths)
– Phyla: Platyhelminthes, Nematoda
*algae are not emphasized here, but remember seaweed is source of agar!
Kingdom: Fungi
• Unicellular Budding Yeasts
Saccharomyces (Baker’s Yeast)
Kingdom: Fungi
• Multicellular, Spore-forming Molds
– Filamentous Hyphae
• Mycelium-mass of hyphae
– Sexual and Asexual spores:
• Sexual spores
– zygospores-- Rhizopus
– ascospores--Peziza
– basidiospores--Coprinus
• Asexual spores
– conidiaspores--Penicillium
• Sporangiospores (seen on Rhizopus slide)
Phylum: Zygomycota
Rhizopus zygospores
(and sporangium)
Rhizopus lifecycle model
‘sacs’ of spores
Rhizopus
Phylum: Ascomycota
8 ascospores per ascus
Phylum: Basidiomycota
Gills of Coprinus
with basidiospores
Opportunistic pathogens
(know the associated mycoses)
Aspergillus
Candida albicans
Note
epithelial
host cells
and
bacteria
as seen in lab
Protozoa (protists)
• Recognize these as unicellular heterotrophic
eukaryotes, and name them.
• Know the motility appendages, if any.
• Know the associated parasitic diseases, if any, by
name, target tissue/organ.
• The following is a list of the protozoa from lab and
then a closer look at our slides and remember:
– Test yourself by covering labels!
– Let the scientific names help (some are very informative!)
• Example: vaginalis, spiralis, apicomplexa
• Ciliates
– Paramecium
• Flagellates
– Trichomonas vaginalis
– Trypanosoma (in blood smear,
exoerythrocytic)
• Amebas
– Amoeba proteus
• Apicomplexa
– Plasmodium (ring stage in blood
smear)
Ciliate
Ciliate model
Flagellate
Note: nucleus, flagella and axostyle
Flagellate
Trypanosoma sp.
More of the same…
RBC’s
Note position of parasites relative to blood cells
Apicomplexan
Note position
of parasites
relative to
blood cells
Ameba
Amoeba with pseudopodia
Kingdom: Animalia
• 2 phyla of parasitic worms referred to as
‘Helminths’
– Platyhelminthes—Flat in cross section
• tapeworms and flukes are parasitic
– Nematoda—Round in cross section
• ascarids, trichinas, pinworms, filarial worms
• Associate each type with a genus and a
disease (by target tissues/organs)
Phylum: Platyhelminthes
• 2 groups of parasitic flatworms
–Cestoda: Tapeworms
• Taenia
–Scolex and Proglottids (know
functions)
–Trematoda: Flukes
• Clonorchis
Highly magnified view of
mature proglottid with eggs
Fluke
Clonorchis
Phylum: Nematoda
(Roundworms)
• Ascarid worms
– Ascaris (preserved
specimen)
• Trichina worms
– Trichinella cyst in pork
skeletal muscle
• Pinworms
– Enterobius vermicularis
LARGE intestinal roundworms
Ascaris
Trichina worms
(nematodes)
Trichinella spiralis
(aptly named!)
Enterobius vermicularis
Note absence of
specialized
structures for
attachment
as seen in lab