Give examples of “differential staining”
- Gram stain (+ve purple/ -ve pink)
- Acid fast
- Capsule stain
- Flagella stain
- Endospore stain
Explain results of Gram staining
Purple = Gram positive
Thicker peptidoglycan layer → traps the crystal violet stain even after decolourization → more stain retained → purple
Pink = Gram negative
Thinner peptidoglycan layer + outer membrane → allows the crystal violet stain to wash out during decolourization → less/no stain retained → pink
Name cocci & bacilli in pairs/ chains/ clusters
- Diplococci/ Diplobacilli
- Streptococci/ Streptobacilli
- Staphylococci
What does “clear zone” in the blood agar test mean?
Hemolysis (breakdown of RBC)
What does a “yellow” result in the Mannitol (sugar) test mean?
Fermentation of sugar (feature of pathogenetic strain) produce acids as a byproduct that lowers the pH and turns the red medium to yellow
⭐What are the 5 steps to be considered when making antimibrobial agents?
(of animal virus multiplication)
- ATTACHMENT of virus to host cell 附著
=> block viral receptor - ENTRY of viral nucleocapsid 侵入
=> block fusion process - SYNTHESIS of viral proteins and nucleic acids 幹活
=> interfere with the process - ASSEMBLY of virion (infectious form of a virus) 組裝
=> interfere with the process - RELEASE of progeny virions 放出後代
=> block release
⭐What are some targets that antibiotics have but antivirals don’t?
Blocking vital (必要的) metabolic processes in bacteria
- inhibit enzymes in cell wall & cell membrane synthesis
- inferring (推斷) DNA and protein production
