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Free from germs or microorganisms and their toxins.
Aseptically treat using the inner flame or "inner cone" because it is the hottest part of the flame.
Make sure incubate at 37 degrees celsius/Body temperature
A process that dilutes out and separates cells on a plate.
- Fixes cells to the glass slide
- Kills the cells to prevent contamination
To coagulate cytoplasmic proteins
Why we need contrast in lab
So the specimen can be visible of the microscope field
High on the pH scale
Alkaline, "not easy"
4 Basic Dyes
- Crystal Violet
- Methylene Blue
- Safranin (red)
- Malachite Green
Basic Dyes are + charged to stain - charged cells
What is Dye/Stain
Solvent (Water or Ethanol)
Is the colored molecule of the dye/stain
Two parts: Chromophore & Auxochrome
Molecules that gives color to the dye
- Group of atoms attached to chromophore
- The + charged portion of the chromogen
The study of shape/structure of organisms
Another word for spherical
Another terms for "rod like"
Another term for Spirals
Referred to as "chain-like"
Refers to clusters or bunches
The Gram Stain
- A very important ID procedure used in microbiology
- Founded by Hans Christian Gram in 1884
2 Types: Gram Neg and Gram Pos
Gram Positive Bacteria
Cell wall has a thick peptidoglycan layer.
(Staphylococcus Epidermis/ Purple)
Gram Negative Bacteria
- Cell wall has a thinner peptidoglycan layer
- Also contains higher lipid content
(Citrobacter freundii / Pink cells)
Why is iodine used in gram stains?
Used in gram stains as a reagent to bind with the CV creating a CV-I complex.
Making the the the complex insoluble and produces much larger particles.
Used in gram staining to stain from gram negative cells
Found in cell walls of bacteria.
What stops gram positive cells from decolorization?
The acetone used in decolorization shrinks and dehydrates peptidoglycan layer. Trapping the CV-I complex.
Why do gram neg cells decolorize with acetone?
Because acetone destroys outer lipid layer, shrinks and dehydrates peptidoglycan layer but leaves large pores for dye to escape.
Factors that effect gram slides
- Age- Only young cultures should be used (18-24 hrs)
- 48 hours + is old
- Acidic Cultures- Damages cell walls, CV wont stain well, Media must be sugar free)
4 acidic dyes
- Nigrosin (Black)
- Congo Red
- Eosin (Red)
- India Ink (black)
- Acidic Dyes are - charged so the - charged cell repels the ink.
Why use negative stains
- Negative stains are used when the cell is too sensitive to be heat fixed.
- Acidic/negative stains reduce cell shrinkage
General Characteristics of Fungi
- Cell wall made of chitin (polysaccharide)
- Absorptive Heterotrophs
- Saprophytes (Decompose decaying matter)
Decompose decaying matter
How do fungi obtain their food?
They are absorptive heterotrophs
Secrete enzymes to decompose, then absorb nutrients
Two types of fungi
Divivded based on appearance
- Unicellular Yeasts
- Filamentous molds
Individual fungal filaments
Fibrous network of hyphae
Which fungi do not form mycelium?
Produce colonies that look like bacteria
What is the name of bread mold?
White or grayish cottony growth
Characteristics of Rhizopus
- White mycelium
- Black sporangia (Where spores are)
Characteristics of Aspergillus
Green-yellow or brown colonies with white edge
Which molds smells like dirt and has a yellow mycelium?
Also contains black conidiospores (asexual spore)
The study of mold
Which mold is green with a white apron and radially furrowed colonies
- White apron
- Radially furrowed colonies
What are they two types of microscope techniques for studying fungi
- Tape Mounts
- Slide Cultures
- Glass slide
- Lactopheonol Cotton Blue (LPCB)
- Sabouraud's Dextrose Agar (media)
- Inject the fungi into the media
Advantages and dis advantages of tape mounts and slide cultures
Tape mounts are fast, easy and last a long time. But the structures are not preserved
Slide cultures preserve fungi but it takes a few days to grow
Two types of fungal spores used in reproduction
- Sporangiospores (Rhizopus)
- Conidiospores (penicilluim or Aspergillus)
- Sexual Zygospores - Found in Rhizopus and this is the location where nuclei fuse