T3 NEW Flashcards
(39 cards)
COMPARE
Toxigenicity and Toxemia
Toxigenicity is the clinical term for the capacity germs to produce toxins
Toxemia blood-poisoning
COMPARE
Sepsis and Septicemia
Sepsis is infection, invasion, or disease by pathogens or their products
Septicemia disease resulting from infection of the blood.
COMPARE
Bacteremia and Viremia
Bacteremia- infection of the blood by bacteria
Viremia -infection of the blood by Viruses
Virulent, Non-virulent, & Avirulent microbes
Virulent: degree to which organism can cause disease
Non-virulent: low degree/ no symptoms
Avirulent: non-pathogenic/ normal flora
Classify exotoxins to 3 functional groups according to where they attack.
Cytotoxin : Cell poisons, specific (LOCALIZED)
- Cardiotoxin
- Hepatotoxin
- Leukotoxin
Neurotoxin: Nerve & brain damage (SYSTEMIC)
Enterotoxin: Food Poisoning ( SYSTEMIC)
COMPARE PROFILE OF GRAM POSITIVE BACTERIA A. Periplasm B. Outer membrane C. Effect of Lysozyme D. Lipo-Polysaccharides
Gram + A. Peri: Absent B. Outer Mem: Absent C. Lyso: High D. Lipo- Virtually none
COMPARE PROFILE OF GRAM NEGATIVE BACTERIA A. Periplasm B. Outer membrane C. Effect of Lysozyme D. Lipo-Polysaccharides
Gram - A. Peri: Present B. Outer Mem: Present C. Lyso: Low D. Lipo: High
Compare Differential Staining to Simple Staining
Simple Staining uses just one basic dye because it highlights the specimen with color in contrast to a clear background.
Differential Staining emphasizes bacterial diversity with color, using 2 basic dyes with contrasting colors to stain bacteria differently.
Identify reagents
Reagents: Methylene Blue Safranin Crystal Violet Malachite Green Carbol Fuchsin
Chemical Groups of the Dyes used
Basic Dye- transfers & stains
Acidic Dye- neg cgarged/ stain background/ nigrosin
Neutral Dye: rarely ever used
List the steps for Gram staining and what each step does to the cell
- Crystal Violet: Primary Stain applied to the Air-dried, Heat-fixed. (dye enters the cytoplasm)
- Bacteria initially take on the color of the Primary Stain but some will eventually retain it while others will not.
- To boost dye retention, Iodine a Mordant fixes the primary stain to the smear. (forms large crystals with the dye that are too large to escape the cell wall)
- Decolorization by alcohol makes some bacterial cells colorless, but not others. (gram + /alcohol dehydrates the peptidoglycan of gram + cells to make it more impermeable to the crystal violet-iodine.)(gram -/ alcohol dissolves the outer membrane of gram - cells and even leaves small holes in the thin peptidoglycan layer.
- Initial rinsing with water
- Applying Secondary Stain: Safranin (adding safranin turns the cells pink or red.)
- After rinsing with water, the slide is blotted dry and observed
Purple POSITIVE (+)
Red NEGATIVE (-). I
What are ‘Plasmids’ and how do they affect toxigenicity?
Genes responsible for bacteria to produce most exotoxins:
Plasmids are small, usually circular, double-stranded DNA molecules. Can dd 5-100 genes. genes for such activities such as antibiotic resistance, tolerance to toxic metals, production of toxins and synthesis of enzymes.
What are ‘Phages’ and how do they affect toxigenicity?
Genes responsible for bacteria to produce most exotoxins: Phages are viruses that infect bacteria.
List some properties of enzymes
Make reactions possible by activation Break down things really fast Proteins Work in small amounts Reusable -100% recyclable Inactivated (denatured) by heat Specific; exclusive for one reaction
Estimate Bacterial Exotoxins that have enzymatic nature
40% aprroximately
How does their enzymatic nature affect exotoxin function?
Because of the enzymatic nature of most exotoxins, even small amounts are quite harmful because they can act over and over again.
Exotoxins: What are they and where do they come from?
They are proteins, many are enzymes, produced inside some bacteria as part of their growth and metabolism and are secreted by the bacterium or released following lysis. Many are enzymes that catalyze only certain biochemical reactions.
Exotoxin: Which microbes make them?
Mostly Gram Positive Bacteria that eventually secrete or release them from their cells. Bacterial plasmids or phages.
Exotoxin: How do they work and what is their Toxigenicity?
They work by destroying particular parts of the host’s cells or by inhibiting certain metabolic functions.
Toxigenicity: diseases caused by bacteria that produced exotoxin are often caused by minute amounts of exotoxin, not by the bacteria. Among the most lethal and specific substances known.
FLAGELLA STRUCTURE/BASAL BODY Describe Basal Bodies and determine how their rings are distributed in: Gram Positive Cell wall and Plasma Membrane.
Basal body is composed of a small central rod inserted into a series of rings.
Cell Wall: 0
Plasma Membrane: 2
FLAGELLA STRUCTURE/BASAL BODY Describe Basal Bodies and determine how their rings are distributed in: Gram Negative Cell Wall layers, Plasma, and Outer Membranes
Basal body is composed of a small central rod inserted into a series of rings.
Cell Wall: 2
Plasma membrane:2
Outer membrane: 0
What are toxins and where do they come from?
Toxins are poisonous substances that are produced by certain microorganisms.
Which microbes make them?
Produced by bacteria during their normal growth and activity.
Estimate the general and specific numbers of toxins.
220 Different Types
2 General types: exotoxin & endotoxin
40% cause disease specifically
