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19 Cards in this Set
- Front
- Back
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What are three other pathogenic lysogenic conversions? Name the toxin as well.
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Streptococcus pyogenes (erythrogenic toxin)
Clostridium botulinum (botulinium toxin) Vibrio cholerae (cholera toxin) |
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What was responsible for the toxigenic properties seen in diphtheria?
Describe Freeman's 1951 experiment that showed this conversion. |
The lysogenic conversion of C. diphtheriae
He took non pathogenic C. diphtheriae and combined it with bacteriophages from pathogenic C. diphtheriae. The result was the transduction of the genes associated with diphtheria toxin. |
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What is lyosgenic conversion? Name an example.
Bacteriophages can contain... The toxin causes diptheria; it gets transcribed and is basis of... |
It occurs when a normal temperate bacteriophage lysogenizes a cell and one or more genes of the prophage are expressed.
Ex: Corynebacterium diphtheriae infected with the phage ß. toxin genes lysogenic conversion |
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Transduction was first described by BLANK and BLANK in 1952 for Salmonella and phage P22.
In this process, BLANK serves as a vehicle for transfer of bacterial DNA from one bacterium to another. It occurs in 2 ways, which are... |
Zinder and Lederberg; Salmonella
bacteriophage Generalized or Specialized, restricted. |
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BLANK transduction involves virulent bacteriophage; DNA inside that is phage or host; one cycle (lytic cycle)
BLANK transduction involves phage and bacterial DNA; usually see temperate bacteriophage; two cycles (lytic/lysogenic) |
Generalized
Specialized |
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In transduction:
1. Tips of bacteriophage on the tail fibers are... 2. What are two ways to determine presence of bacteriophages? 3. Phages multiply in.. |
specific for certain bacteria.
Use a 0.22 micrometer filter or DNases metabolizing bacteria |
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In transduction, what 3 things do phages need in the host cell?
What are the different shapes of a phage? |
need protein synthesizing machinery, amino acids, and energy producing systems.
icosahedral (simple), filamentous, icosahedral tailness. |
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What are the clear zones seen on agar plates where you find bacteriophage called?
What three methods do bacteria employ to combat bacteriaphages? |
Plaques
They modify their host cell receptor to knock out viruses, use endonucleases, as well as methylate host chromosomes. |
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Summarize how bacteriophages overtake a bacterium and reproduce.
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Adsorption
injection of DNA transcription of phage DNA phage proteins are made phage structures made DNA packaged into phage and assembled Lysis |
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In generalized transduction, BLANK DNA fragments are transferred and occurs in any population of bacterial susceptible...
Infection of host initiates a BLANK cycle, where phage DNA is BLANK and BLANK into phage particles and released by cell lysis. |
random; to infection by bacteriophages.
Lytic; replicated; packaged |
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T or F: In generalized transduction, defective phages are nonvirulent.
What extra thing do defective phages have? |
FALSE FOOL. Complete and defective phages are virulent.
Defective phages still contain host DNA. |
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As a method of gene transfer, defective phages have a BLANK BLANK of being transferred to a recipient.
In GT/Defective phages, BLANK% of host chromosome is packaged |
low frequency
2% |
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In specialized transduction, BLANK DNA is inserted into a site on BLANK DNA chromosome. This combined DNA is called a...
What is specialized transduction used for ? |
Phage; bacterial; prophage
used for gene order and chromosomal mapping and determining gene's relative location on a chromosome. |
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The probability of a given gene being transferred to a recipient cell is increased in...
A bacterium carrying a prophage is BLANK. The phage DNA integrates at a... Name a specific example of the above phenomenon. |
specialized transduction
lysogenic specific attachment site in the bacterial chromosome. Ex: The phage lambda, always inserts at the same location in the DNA of a specific host bacterium. Upon induction with some sort of agent or UV light, a small portion of host DNA is removed with the phage DNA. |
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Why does specialized transduction occur only with temperate bacteriophages?
When a prophage is exposed to UV light or another environmental stimulus, what happens? |
Because they incorporate their DNA into host chromosome without cell lysis and instead go into lysogensis
The phage DNA is removed and the cell enters the lytic cycle. |
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In specialized transduction, progeny bacteriophages lack a complete phage genome and are considered BLANK.
they are still able to inject their genetic material into recipient cells and the efficiency of transfer for specific genes... Name an example |
Defective
is very high Ex: galactose genes and the lambda phage. |
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When you combine defective transducing particles with normal helper phage particles, specialized transduction is...
If induced the infected bacteria will... When this is used to infect a specific recipient... |
HIGH FREQUENCY
produce normal and defective phage particles. about 50% of the cells will be transduced. |
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What is abortive transduction?
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The transducing phage DNA is not incorporated into the host chromosome.
The phage DNA neither replicates or is destroyed, it just transmitted in daughter cells as the cells divide by binary fission. Eventually it will become less and less. |
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Can bacteriophage be used for antimicrobial treatment?
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Used in the 1930s; nowadays used on MRSA
Three methods of phage attack are hopefully not employed but overall this is no longer a useful method |
