Discussion Schedule for BIOL/MCBL 121 (Winter 2011) Week 1: Jan. 3 - 7 The TAs (James Wong and Shushu Jiang) will explain homework assignments, group project presentations and expectations. Groups of 4 students will be formed for group projects Week 2: Ja
Major limitation of Kochs Postulates
The pathogen must be able to grow in
artificial media to obtain PURE CULTURE
Pathogens requiring complex nutrients
from the host will fail
Slow growing organisms will fail
Pure culture isolation
Major component of evolutionHow gene is
transferred from adult to adult
Gene Transfer, Mutation and
Single mutations are slow because of high delity of
DNA Pol (proofreading)
The Mosaic Nature of Genomes
Microbial genomes have undergone
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
The Entire genetic complement of DN
Fate of the Entering DNA
Plasmids exist in the recipient bacteria as
DNA could incorporate into the recipient bacterial
genome by homologous recombination.
Homologous DNA sequences must be present in the
Use inorganic molecules as their electron donors
These donors are often weak so you want strong
acceptors like oxygen.
H2 gas is a really strong donor.
Some gastric bacteria can oxidize H2 as the electron
Most inorganic electron donor
ParC: sequences on the plasmid that bind to ParR
ParM: forms protein filaments needs ATP.
A toxin-antitoxin module in plasmids for self-maintenance.
Two adjacent genes encoding a toxin (protein) and an
Large genome: ~ 200 genes
Enzymes: lysozyme, DNA replication enzymes, DNase.
A sigma factor.
Lytic cycle of T4 phage
The T4 phage life cycle (from entering an E. coli cell to its
destruction) takes approximately 25 mi
Only in prokaryotes due to coupling of transcription
RNA that is is synthesized by RNA Pol is
immediately fed into ribosomal units for translation
Physically, Ribosome and RNA pol are not far apart
so position of ribosome can affect transc
Low MOI: Many bacterial particles out there because
there are cells that can be affected>lytic cycle
CII is hydrolyzed by FtsH due to low CII vs. FtsH ratio.
The transcription of cI from PRE is not activated.
Cro accumulates and occupies the OL and OR
Viruses of Bacteria:
Chapter 6 and 11
Only way for a virus to survive is to infect any host
Viruses are not living cell, just have nucleic acid wrapped in protein.
Bacteria viruses cannot infect humans and a human virus cannot infect a plant
Coregulation can be under the control at different levels. At the operons, like what we saw before. Also at Regulons: these can be scattered on the genome (unli
consecutive), they are like operons because they are regulated by the same regulatory protein.
WHO: Worldwide mortality due to infectious diseases
All infectious diseases
Lower respiratory infections
Toxins Subvert Host Function
Categories of exotoxins:
Cause host cell membrane leakage.
Inhibit host protein synthesis.
Over-activate host immune system super
Activate secondary messenger pathways.
Affect cAMP pro
Molecular clock: temporal information contained in a
Chronometer is used to determine evolutionary distance.
Criteria for a chronometer:
Universal molecule found in all organisms.
Has conserved functions in all orga
Improved (Modified) Penicillins
Penicillin is ineffective for Gram negative bacteria.
Has to go through porins to pass the outer membrane.
Bacteria secrete -lactamase to hydrolyze the -lactam ring
in penicillin-related antibiotics.
T4SS T-DNA Transfer
Ti Plasmid in Agrobacterium tumefaciens F factor.
T4SS transfers a DNA fragment into plant cells.
Transfer DNA (T-DNA): transferred as a single-stranded DNA.
Oncogenic genes: encoding phytohormones.
Opine synthesis genes.
Gram Negative Cell Wall
A thin layer of peptidoglycan
Porins: Pores on the outer membrane
that allow protein and other material to
come in and out. Not just holes, they will
bind preferentially to other material.
Murein Lipoprotein/ Braun
General Course Information
Introduction of microorganisms
History of Microbiology
Rm 1234C Genomics Building
Office hour: 10:10-11:00 PM on Mondays and
BIOL/MCBL 121 Winter 2011: Homework Assignment 1 1. Describe Louis Pasteurs famous swan neck flask experiment and how it disproved the theory of spontaneous generation? 2. List Kochs postulates. What is the major limitation of Kochs postulates? 3. What ar
General Course Information Introduction and history of Microbiology
Professor Ma Rm 1234C Genomics Building [email protected] Office hour: 11-12:30 PM Wednesday Text book: Microbiology: An e
Structure and Function of Prokaryotic Cells
Outline Differences between Prokaryotes and Eukaryotes Nucleoid Cell membranes Cell walls Locomotion Inclusion bodies
Structural differences between Prokaryotes and Eukaryotes
Prokaryotes have no defined organ
Glycocalyx: network of polysaccharides extending from cell surface survival, attachment, virulence Capsule: well organized glycocalyx; difficult to remove S-layers Gram positive bacteria layers of protein or glycoprotein Common among Arch
Symport and Antiport
Coupled transportation Gradient of one molecule provides energy to transport another The transporter proteins have two solutebinding sites one for the driving molecule and another for the co-transported molecule
Symport: Gradient of
Aerobes: able to grow in the presence of O2 Obligate aerobes: can not grow without O2 Anaerobes: can grow in the absence of O2 Aerotolerant anaerobes: can grow in O2, but can not utilize it Obligate anaerobes: growth is inhibited by O2 Anaerobic o
Organic compounds are digested and entered the central pathway Polysaccharides Converted to glucose and eventually acetyl-CoA Lipids, amino acids and aromatic compounds Converted to acetyl-CoA Acetyl-CoA enters the TCA cycle and the electron
The Entire genetic complement of DNA in a cell = genome Genomes of bacteria are usually made up of chromosome(s) and plasmids One circular chromosome Can be linear Many bacteria contain plasmids Bacterial genome = 0.69.4 x 106 bp About
Extrachromosomal DNA, usually circular Has its own origin of replication Usually do not code for essential proteins Important for bacteria to adapt to the changing environments (e.g. antibiotic treatments) Size varies: several kilobas