Examine differences between Gram

Examine differences between Gram - pathogenesis eg....

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Examine differences between Gram + and Gram - cell walls. To the left is a gram stain of Staphylococcus epidermis done in our lab. The spherical cocci are tiny and are gram positive because they retain the primary stain crystal violet. Below is a gram stain of a mixed culture of Micrococcus luteus (box like arrangements of cocci) with Escherishia coli . Micrococcus is gram positive while E.coli is gram negative. E. coli consists of very small delicate rods seen pink because they lose the primary stain as they are gram negative. The gram negative cell wall of E. coli is much thinner than the wall of Micrococcus. Coli's cell wall also contains less peptidoglycan and more lipopolysaccharide. 3. Explain LPS and its role as an endotoxin and fever producer. 4. Also mention Spheroplasts and Protoplasts, L forms. Chlamydia and Rickettsia. d. pili and fimbriae: Structures that allow sticking to surfaces---important in
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: pathogenesis eg. UTI'"s, biofilms, teeth, glass, rocks (Pellicle formation in culture). Some Pili specialized. Sex pilus. 1946 experiment with minimal media showed genes transfered requiring contact. Define: auxotroph, prototroph, mutation rate. Minimal media (Glucose salts media). Mating types. F+ and F- (movie) e. other structures: 1. Chromatin Body--Long cirucular piece of DNA. Couple of thousand genes. It is haploid and relatively easy to manipulate eg. ..stick other genes into using bioengineering techniques. 2. Plasmids---small cirucular pieces of DNA (F factor is on a plasmid, Antibiotic resistance carried on plasmids). They are easily transferred from one cell to another. During sexual transfer recipient becomes F+. 3. Ribosomes---70s----50 + 30. Two parts. e. Mesosomes, endospores, fat globules, polyphosphate, Sulphur granules, magnetosomes, photosynthetic structures....
View Full Document

Page1 / 2

Examine differences between Gram - pathogenesis eg....

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online