Microbiology

1.Eubacteria (bacteria) & Archaea

2. Their DNA is not enclosed within a membrane and is usually a singular circularly arranged chromosome.

3. DNA not asso. with histones (special chromosomal proteins found in eukaryotes)

4. They lack membrane-enclosed organelles.

5. Cell walls almost always contain the complex polysaccharide peptidoglycan.

6. Cell Division-binary fission. DNA is copied & the cell splits into two cells.

1. Protista, Fungi, Animalia, Plantal

2. DNA is in Cell nucleus, separated from the cytoplasm by nuclear membrane & found in multiple chromosomes.

3. Asso. with chromosomal proteins histones/nonhistones

4. Have a # of member enclosed organelles (mitochondria, endoplasmic reticulum, Golgi complex, lysosomes & sometimes chloroplast)

5. Cell walls when present are chemically simple

6. Cell division-mitosis. pg.77

Both contain....

1.nucleic acids

2. proteins

3. lipids

4. carbohydrates

5. chemical reactions to metabolize foods, build proteins, & store energy.

1. Most bacteria range 0.2-2.0 um in diameter & 2-8 um in length.

2. Shapes/arrangements
-coccus/cocci
-bacillus/bacilli
-diplococci/bacilli(pairs)
-streptococci/bacilli (long chains)
-coccobacillus
-tetrads (bundle of 4 cells)
-sarcinae (bundle of 8 cells)
-Staphylococci (cluster of cells)
-spirilla/sprillum (helical,rigid)
-spirochete (helical,flexible)

pg 79

-Has cell wall (definite shape)

-photosynthesis

-can range 10-100um

-No cell wall/no definite shape

-can range 10-30 um

-Centrioles-anchor points for the chromosome during animal cell divison & they ensure even sorting of the chromosome during mitiosis.

-Lysosome- has an enzyme called lysozynes. Ensures that the cell cleans out old dead cells & ensure cancer cells are destroyed.

In order by degree of complexity

• Eubacteria
• Archaebacteria
• Fungi
• Protista
• Plantae
• Animalia

-microorganisms commonly called Bacteria

-Unicellular that have prokaryotic Cells with cell walls

-only group of living things that has Peptidoglycan as cell wall material

-May be Coccus, Bacillus, Coccobacillus, Vibrio, Spirillum, or Spirochete

-May be arranged as Single-, Diplo-, Strepto-, Tetrad, Sarcina, or Staphylococcus

-Makes up the bulk of common disease-causing microbes

-Microscopic Prokaryotic Cells, Unicellular, and Microorganisms

-has a Cell wall

- Cell wall not made of Peptidoglycan

-Typically live in extreme environments not suitable for most organisms

- are Heterotrophs that cannot carry out photosynthesis

-Many are microorganisms and microscopic

-Eukaryotic with cell walls.The cell walls contain Chitin

1. Unicellular forms of Fungi are called Yeasts

2. Multicellular forms of fungi are the Molds

- Multicellular types have functional tissues and organs.

-Common causes of food Spoilage and decomposition

-Several are large and non microscopic

-Microscopic but not prokaryotes

-Eukaryotes but not Animals, Plants, or Fungi

-Unicellular and Multicellular forms

-Some are autotrophs while others are heterotrophs.

1. Unicellular Animal-like Protista without cell walls are called Protozoa.

2. Plant-like photosynthetic Protista with cell walls of cellulose are Algae.

3. Fungal-like Protista with chitin cell walls, like Fungi, are Slime molds.

-are not microorganisms or microscopic

-All are Complex Multicellular organisms and Eukaryotic

-cells have cell walls, which contain Cellulose

-all autotrophic and can carry out photosynthesis

-All are complex Multicellular organisms

-not microorganisms or microscopic

-have Eukaryotic cells but do not have Cell walls

- Their cells do not contain Chloroplast and cannot carry out photosynthesis.Therefore, nutritionally, they are Heterotrophs.

1. the Cation (+) is the chromophore

2. are used for positive or direct staining and the specimen is stained while the background remains clear.

3. BASIC dyes are the most common in Microbiology

4. Basis dyes include: crystal violet, methylene blue, malachite green, & safranin

1. the Anion is the chromophore in an Acidic Dye

2. Acidic dyes are not attracted to most types of bacteria because the dye's negative ions are repelled by the negatively charged bacterial surface, so the stain colors the background instead.

3. Major acidic dye used in Microbiology is Nigrosin. It colors the slide and background black, leaving the specimen clear.

1. Both the cation and anion are chromophores.

2. NEUTRAL dyes are almost never used because it does not create the desired contrast between background and specimen

- uses a dye, which is a colored organic salt, to produce contrast between a specimen and its background.

-Staining the specimen but not the background

- Basic dyes are used for positive or direct staining and the specimen is stained while the background remains clear.

-preparing colorless bacteria against a colored background

-Acidic dyes are used for negative staining.

-an aqueous or alcohol solution of a single basic dye.

-the primary purpose of a simple stain is to highlight the entire microoraganism so that cellular shapes & basic structures are visible.

-react differently with different kinds of bacteria & can be used to distinguish them.

-Gram stain

-used to color & isolate specific parts of microorganisms such as endospores & flagella, & to reveal the presence of capsules.

-a chemical that is added to the solution to intensify the stain

-a stain-enhancer

The first basic dye applied during staining procedures.

Stains like safranin that have a contrasting color to the primary stain.

1. 2 dyes. Use dyes that will go into cell

2. basic dyes

3. ...contrasting color

-crystal violet-safranin
-carbol fuchin-methylene blue
-malachite green-safranin

4. Apply mordant-(helps enhance primary dye)

-binds the color to the cell/specimen

5. Decolorizer(ex. bleach, alcohol, acetone, acid, water)

lecture notes 4

1. It is spread thin on a transparent glass slide as a Smear.

2. The smear is air-dried before staining

3. Just before staining, the dried smear is fixed using a physical fixing agent, like heat, by rapidly passing it over open flame

4. Fixing prevents loss of specimen and preserves its structure. Chemical fixing is also possible using a fast-drying preservative like acetone.

1. Is the standard procedure for identification of bacterial infections and diseases in Hospitals and Diagnostic Labs.

2. It uses ability to retain or lose the Primary Stain to classify bacteria into two large groups: Gram Positive and Gram Negative according to their final colors.

1. Crystal Violet is the Primary Stain.

2. Iodine is the Mordant: Crystal violet behaves differently in the presence of iodine and is fastened to bacterial cells better, especially if they are Gram positive.

3. Ethanol or Acetone-Ethanol is the decolorizer.

4. The Counterstain is Safranin.

5. After rinsing with water, the slide is blotted dry with bibulous paper and observed.

Gram Positive bacteria become Violet

Gram Negative bacteria look Pink or Red.

distributed over the entire cell

single flagellum at one pole

the flagella tend to be a bundle at a pole.

flagella (single) at both poles of the cell

1. Response to Gram Stain-the cell walls of Gram positive bacteria resist decolorization and keep the color of the primary stain - Crystal Violet

2. Gram-positive cell walls are essentially fat-free!

3. Gram-positive bacteria cell walls have multiple layers

4. Teichoic Acid is exclusive to Gram-positive bacteria.

5. The Basal Body of Gram-positive bacteria also has two rings that anchor it to only the Plasma Membrane with no additional rings in the thick, multi-layered, Peptidoglycan cell wall. So, the Basal body of Gram-positive bacteria has just 2 rings.

6. Toxins-Exotoxins

1. Response to Gram Stain: Gram negative bacteria are decolorized by alcohol allowing them to attract Safranin; the counterstain.

2. Gram-negative bacteria cell walls contain high levels of Lipids in form of phospho-lipids, Lipo-polysaccharides, or Lipo-proteins.

3. Gram-negative bacteria cell walls have just a single layer of peptidoglycan covered by a thick outer-membrane of lipids.

4. Teichoic Acid is not in Gram-negative bacteria

5. Between the inner Plasma Membrane Lipid and the Outer Lipid membrane of Gram-negative bacteria Cell wall, is a gap that is partly made of peptidoglycan.

6. Gram-negative bacteria, the Basal Body consists of 4 rings: two in the Plasma Membrane and one in each of the mixed inner Peptidoglycan and Lipid layers of the Cell wall.

7. Toxins-Endotoxins & Exotoxins

Robert Hooke

Theodore Schwann & Matthias Schleiden created the cell theory based on works by:

-Robert Hooke
-Anton Van Leeuwenhoek
-Lorenz Oken
-Robert Brown

Hans Christian Gram

Carl Weigart