If post is spelled P-O-S-T and most is spelled M-O-S-T, how do you spell the word for what you put in the toaster?

Microbial Genetics

General Biology

SUNY Orange at S. S. Seward Institute

It's At The 20! The 10! Can The Flu Go All The Way?

by Laura Lorson

Tobacco Mosaic Disease

Red Neck Bird Dogs

Bacterial and viral growth curves

Lytic cycle of phage T4

Viral structure

Phage Infecting Bacteria

• Sorenson animation

• T4 Assembly

Viral reproductive cycle

Adenovirus

Reproductive cycle of an enveloped virus

HIV infection

Couple at AIDS quilt

HIV, a retrovirus

Smallpox

Measles

Polio

Hepatitis

Influenza epidemic

Influenza Virus

• video

Herpes

Emerging viruses

Deer Mouse – vector for hantavirus

Viral infection of plants

Tobacco mosaic virus

Prion Diseases

Creutzfeldt-Jakob Disease

Kuru

A hypothesis to explain how prions propagate

Replication of the bacterial chromosome

E. coli

E. coli dividing

Bacterium releasing DNA with plasmids

Plasmids

Genetic recombination produces new bacterial strains:

Transformation

Transduction

Conjugation

Transformation

• The alteration of a bacterial cell’s genotype by the uptake of naked, foreign DNA from the surrounding environment

Detecting genetic recombination in bacteria

Transduction

• Occurs when a phage carries bacterial genes from one host cell to another

• Generalized transduction – a small piece of the host’s cell degraded DNA is packaged within a capsid

• Specialized transduction – occurs when extra DNA is taken when prophage genome is excised

Transduction

Transduction

Transduction

Transduction

Conjugation

• Transfers genetic material between 2 bacterial cells temporarily joined

• F factor – about 25 genes, most required for production of sex pili– Either in chromosome or on plasmid– Episome – any genetic material that

undergoes reversible incorporation into a cell’s chromosome

• Ex. F plasmid, any temperate phage

Bacterial mating

Conjugation and recombination in E. coli

Conjugation and recombination in E. coli

Conjugation and recombination in E. coli

Conjugation and recombination in E. coli

R Plasmid

• R for resistance

• Also have genes for sex pili

• Therefore can be transferred from one cell to another by conjugation

Transposons

• Pieces of DNA that can move from one location to another in a cell’s genome

• A type of recombination– Chromosome to plasmid– Plasmid to chromosome– Plasmid to plasmid– Chromosome to chromosome (Jumping

gene)

Barbara McClintock, Ph.D., Nobel Prize laureate

Insertion Sequence

• Consists of DNA necessary for the act of transposition

• Requires a transposase gene

• Flanked by a pair of inverted repeat sequences

Insertion sequences, the simplest transposons

Insertion of a transposon and creation of direct repeats

Composite transposon

• Extra genes sandwiched between two insertion sequences

Anatomy of a composite transposon

The control of gene expression enables individual bacteria to adjust their metabolism to environmental change.

Regulation of a metabolic pathway

Regulation of a metabolic pathway

Operon

-a unit of genetic function (bacteria and phages) regulated clusters of genes with related functions

1. gene(s) that it controls

2. Promoter region where RNA polymerase first binds

3. Operator – between promoter and the first gene – acts as on/off switch

The trp operon: regulated synthesis of repressible enzymes

The trp operon: regulated synthesis of repressible enzymes

The lac operon: regulated synthesis of inducible enzymes

The lac operon: regulated synthesis of inducible enzymes

cAMP (Cyclic Adenosine Monophosphate)

Positive control: cAMP receptor protein

Positive control: cAMP receptor protein