Lecture 21 And 22

Front 1

how to detect mutation in a bacteria.

Back 1

1. Genetic screening
2. Direct selection
3. Indirect selection

Front 2

Genetic screening

Back 2

If the mutant has a visible phenotype that is different from the phenotype
of the wild-type (non-mutant) organism, one simply looks at thousands of bacterial colonies
for colonies displaying the mutant phenotype. Phenotype is the outward expression
(appearance under some condition) of the genotype (sequence of the gene).

Front 3

Direct selection

Back 3

A method for finding the mutant bacterium that makes use of a condition
under which only the mutant can grow. For example, one can select mutants that are
resistant to antibiotics by adding antibiotics to the medium. Only mutants resistant to the
antibiotic grow, i.e., they are selected directly.

Front 4

Indirect selection

Back 4

A method using first a condition that kills wild-type cells, but not the mutant
you seek.

Front 5

The Ames test

Back 5

is a biological assay to assess the mutagenic potential of chemical compounds.

Front 6

1.F+ cells contain the plasmid F
2. F plasmid contains about 40 genes which encode proteins that construct a F pilus

3.Other proteins control transfer of a copy of
the F plasmid to the recipient cell.

The recipient cell is F

Back 6

true

Front 7

Genetic map made by mating 1.Hfr and Fstrains.
2. Genetic map is circular.
3.Bacterial chromosome is circular

Back 7

k

Front 8

Types of plasmids

Back 8

1. conjugation
2. R plamids
3. colicin plasmid
4. virulence plasmids.
5. degradative plasmids

Front 9

Conjugative plasmids – transfer themselves into another bacterium
» F factor – makes sex pilus and controls transfer of itself into an F- plasmid
» RP4 is another conjugative plasmid that behaves similarly

Back 9

true

Front 10

R plasmids
» R1 and many others - carry genes that encode enzymes that degrade or inactivate antibiotics, making
cells that carry these plasmids antibiotic resistant
» These plasmids are not conjugative, but if a conjugative plasmid enters these cells and recombines
with the R plasmid, a new plasmid results that is both conjugative and carries antibiotic resistance to
other cells.

Back 10

true

Front 11

Colicin plasmids
» These plasmids make proteins that kill other bacteria

Back 11

true

Front 12

Virulence plasmids
» plasmids that produce a toxin that damages the tissues of the host or another protein that is essential for pathogenesis.

Back 12

true

Front 13

Degradative plasmids
» These plasmids encode proteins that act as enzymes that degrade chemicals in soil or water, for
example, gasoline, toluene, pesticides, camphor.

Back 13

true

Front 14

l Use a plasmid, e.g., pBR322, that
has selectable markers.
l e.g., ampicillin and tetracycline
resistance
l Fragment the foreign DNA with a
restriction endonuclease.
l Open the plasmid in the tetresistance
gene using the same
restriction endonuclease.
l Ligate the vector and foreign DNA
fragments to create recombinant
DNA molecules
l Transform bacterial host cell (E.
coli).
l Select transformants by ampresistance.
l Screen to tetracyline sensitivity

Back 14

k

Front 15

plasmids that are able to form the formation of the conjugation tube and replication of a rolling circle can be spread from a bacterium that has them to one that doesn't have them.

Back 15

true.

Front 16

Detecting mutations in bacteria

Back 16

Genetic screening: If the mutant has a visible phenotype that is different from the phenotype
of the wild-type (non-mutant) organism, one simply looks at thousands of bacterial colonies
for colonies displaying the mutant phenotype.

Front 17

Detecting mutations in bacteria

Back 17

Direct selection: A method for finding the mutant bacterium that makes use of a condition
under which only the mutant can grow.

Front 18

Detecting mutations in bacteria

Back 18

Indirect selection: A method using first a condition that kills wild-type cells, but not the mutant
you seek.

penicillin selection is a powerful indirect selection method.

Front 19

ames test

Back 19

detects whether a substance is a mutagen

Front 20

5 Classes of plasmids

Back 20

Conjugative plasmids
R plasmids
Colicin plasmids
Virulence plasmids
Degradative plasmids

Front 21

plasmids
conjugativie plasmids

Back 21

F-factor is contained on plasmid and contains genes that build the conjugation tube between donor and recipient cells, in a mating-like event called conjugation.

Front 22

R plasmids

Back 22

R1 and many others - carry genes that encode enzymes that degrade or inactivate antibiotics, making
cells that carry these plasmids antibiotic resistant
These plasmids are not conjugative, but if a conjugative plasmid enters these cells and recombines
with the R plasmid, a new plasmid results that is both conjugative and carries antibiotic resistance to
other cells.

Front 23

Colicin plasmids

Back 23

» These plasmids make proteins that kill other bacteria

Front 24

l Virulence plasmids

Back 24

» These plasmids are found in many (not all) pathogenic bacteria. They encode proteins that cause
tissue damage or death of mammalian cells during infection by the pathogen.
» Others encode proteins that help the pathogen survive in the host

Front 25

Degradative plasmids

Back 25

» These plasmids encode proteins that act as enzymes that degrade chemicals in soil or water, for
example, gasoline, toluene, pesticides, camphor.

Front 26

immune system

Back 26

protects host against invading organisms. two parts of the system: humoral immunity and cellular immunity

Front 27

antibody

Back 27

molecules made by the immune system designed to recognize antigens presented by a foreign particle.

Front 28

Antigen

Back 28

protein, nucleic acid carbohydrates, lipids or molecules that elicits an immune response.

Front 29

epitope

Back 29

region of the antigen that binds to the antibody.

Front 30

Opsonization

Back 30

the binding of bacteria by antibodies to prepare for phagocytosis or complement fixation

Front 31

Neutrophil

Back 31

phagocytic cell found in the blood

Front 32

basophil

Back 32

responsible for releasing histamine

Front 33

eosinophils

Back 33

participate in inflammation

Front 34

Monocytes: responsible for stimulating the immune system. Include:

Back 34

Macrophages: phagocytic cells that stimulate the immune system
Histiocytes: are fixed monocytes

Front 35

IgM

Back 35

1st class of antibody made in the immune response to new antigen

Front 36

IgM bind to the surface of a cell or virus

Back 36

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