From one Escherichia coli strain, five Hfr strains were isolated. The location and orientation of the origin of transfer of each Hfr strain are shown in Figure 1. want to use these five strains to map the locus responsible for thiamine synthesis, called thi. Each Hfr strain is sensitive to rifampicin (RifS) and Thi+. Conjugation experiments are performed between each of the Hfr strains and an F- RifR Thi 0 leu 10 20 30 nadD pyrC trp his 50 60 70 cysG 80 90 metA 100 Hfr1 Hfr2 Hfr 3 Hfr4 Hfr5 Figure 1: Chromosome map of Escherichia coli. Five Hfr strains (Hfr1 to Hfr5) were isolated and the location and orientation of the origin of transfer is shown by the arrows in each Hfr strain. Distances in minutes are indicated. Leu: leucine biosynthesis; nadD: NAD biosynthesis; pyrC: pyrimidine biosynthesis; trp: tryptophan biosynthesis; his: histidine biosynthesis; cysG: cysteine biosynthesis; metA: biosynthesis of methionine. 1) What is the selection medium used in these conjugation experiments

From one Escherichia coli strain, five Hfr strains were isolated. The location and orientation of the origin of transfer of each Hfr strain are shown in Figure 1. want to use these five strains to map the locus responsible for thiamine synthesis, called thi. Each Hfr strain is sensitive to rifampicin (RifS) and Thi+. Conjugation experiments are performed between each of the Hfr strains and an F- RifR Thi 0 leu 10 20 30 nadD pyrC trp his 50 60 70 cysG 80 90 metA 100 Hfr1 Hfr2 Hfr 3 Hfr4 Hfr5 Figure 1: Chromosome map of Escherichia coli. Five Hfr strains (Hfr1 to Hfr5) were isolated and the location and orientation of the origin of transfer is shown by the arrows in each Hfr strain. Distances in minutes are indicated. Leu: leucine biosynthesis; nadD: NAD biosynthesis; pyrC: pyrimidine biosynthesis; trp: tryptophan biosynthesis; his: histidine biosynthesis; cysG: cysteine biosynthesis; metA: biosynthesis of methionine. 1) What is the selection medium used in these conjugation experiments

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter17: Bacterial And Viral Genetics

Section: Chapter Questions

Problem 1ITD

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From one Escherichia coli strain, five Hfr strains were isolated. The location and orientation of the origin of transfer of each Hfr strain are shown in Figure 1. want to use these five strains to map the locus responsible for thiamine synthesis, called thi. Each Hfr strain is sensitive to rifampicin (RifS) and Thi+. Conjugation experiments are performed between each of the Hfr strains and an F- RifR Thi leu 10 20 T nadD pyrC trp 30 his Donor strain Hfr1 Hfr2 Hfr3 Hfr4 Hfr5 The results are shown in the following table 60 70 cysG Colonies Thi 1000 0 400 0 25 80 90 metA 1,00 Hfr1 Hfr2 Figure 1: Chromosome map of Escherichia coli. Five Hfr strains (Hfr1 to Hfr5) were isolated and the location and orientation of the origin of transfer is shown by the arrows in each Hfr strain. Distances in minutes are indicated. Hfr 3 Leu: leucine biosynthesis; nadD: NAD biosynthesis; pyrC: pyrimidine biosynthesis; trp: tryptophan biosynthesis; his: histidine biosynthesis; cysG: cysteine biosynthesis; metA…
From an Escherichia coli strain, five Hfr strains were isolated. The location and orientation of the transfer origin of each Hfr strain is shown in Figure 1. You want to use these five strains to map the locus responsible for thiamine synthesis, called thi. Each Hfr strain is sensitive to rifampicin (Rifs) and thi*. Conjugation experiments are performed between each of the Hfr strains and an F strain Rif Thi™. 0 T leu 10 20 T nadD pyrC trp 40 T his 60 70 2) The results are shown in the following table: Donor strain Hfr1 Hfr2 Hfr3 Hfr4 Hfr5 cysG 80 90 1) What is the selection medium used in these conjugation experiments metA Colonies Thi+ 1000 0 400 0 25 100 Hfr1 Hfr2 Figure 1: Chromosome map of Escherichia coli. Five Hfr strains (Hfr1 to Hfr5) were isolated and the location and orientation of the origin of transfer is shown by the arrows in each Hfr strain. Distances in minutes are shown. Leu: leucine biosynthesis; nadD: NAD biosynthesis; pyrC: pyrimidine biosynthesis; trp: tryptophan…
Given what we've discussed in class, what will be most likely outcome if you conjugate an streptomycin resistant ampicillin sensitive methionine auxotroph E. coli strain (engineered to be pir+) that is F- with a streptomycin sensitive non-HFR methionine prototroph strain that is F- and RP4+ but contains pUC18? Colonies on minimal media + ampicillin +streptomycin plates No colonies on minimal media +ampicillin +streptomycin plates
A pure culture of an unknown bacterium was streaked onto plates of a variety of media. You notice that the colony morphologyis strikingly different on plates of minimal media with glucose compared to that seen on trypticase soy agar plates. How can you explain these differences in colony morphology? Also, describe what happens when a nonsense mutation is introduced into the gene encoding transposase within a transposon and why is it more likely that insertions or deletions will be more detrimental to a cell than point mutations?
Given the following phenotypes, explain how the mutation (identified by a (-) superscript) will affect the E. coli grown in lactose medium. l+p+o+z-y+ i-p+o+z+y+ l+p+o-z+y+ l+p-o+z+y+
Draw a diagram/figure to explain the conjugation process (. You should include in the diagram the F- recipient, Hfr Donor and the transconjugant/recombinant recipient. Make sure to include the genes encoding for Leucine, Threonine, Thiamine and Streptomycin resistance in your diagram. How does an Hfr strain of coli transfers chromosomal DNA to an F- strain? What determines how much of the chromosomal DNA is transferred?
) In a conjugation experiment, we used two strains: Hfr: streptomycin sensitive and F-: auxotrophic for isoleucine and threonine, streptomycin resistant. If we interrupt conjugation when only threonine gene has been transferred and spread this mixture on: Minimal media, Minimal media with streptomycin Minimal media with threonine and streptomycin Minimal media with isoleucine and streptomycin LB agar plates with streptomycin On which plates do we expect bacterial growth? Why?
Under what conditions will the following partial diploid strain of E. coli convert chorismate to tryptophan (assume trp mutants function similarly to lac mutants)? trpR* trpP trpO* trpE* trpD* trpC* trpB* trpA*/ trpR trpP trpO° trpE trpD trpC trpB trpA ect the one BEST answer (2 oints! O never O only when tryptophan levels are low O constitutively O only when tryptophan is present O only when chorismate levels are low
. In an interrupted-conjugation experiment in E. coli, thepro gene enters after the thi gene. A pro+ thi+ Hfr iscrossed with a pro- thi- F- strain, and exconjugants areplated on medium containing thiamine but no proline. Atotal of 360 colonies are observed, and they are isolatedand cultured on fully supplemented medium. These cultures are then tested for their ability to grow on mediumcontaining no proline or thiamine (minimal medium),and 320 of the cultures are found to be able to grow butthe remainder cannot.a. Deduce the genotypes of the two types of cultures.b. Draw the crossover events required to produce thesegenotypes.c. Calculate the distance between the pro and thi genesin recombination units.
In a cotransformation experiment DNA was isolated from a donor strain that was proA+ and strC+ and sensitive to tetracycline. (The proA and strC genes confer the ability to synthesize proline and confer streptomycin resistance, respectively.) A recipient strain is proA− and strC− and isresistant to tetracycline. After transformation, the bacteria werefirst streaked on a medium containing proline, streptomycin, andtetracycline. Colonies were then restreaked on a medium containingstreptomycin and tetracycline. (Note: Each type of medium hadcarbon and nitrogen sources for growth.) The following resultswere obtained:70 colonies grew on the medium containing proline, streptomycin,and tetracycline, but only 2 of these 70 colonies grew whenrestreaked on the medium containing streptomycin and tetracyclinebut lacking proline.What would you expect the cotransformation frequency to be ifthe average size of the DNA fragments was 4 minutes and thetwo genes were 1.4 minutes apart?
An Hfr strain that is hisE+ and pheA+ was mixed with a strain thatis hisE− and pheA−. The conjugation was interrupted and the percentageof recombinants for each gene was determined by streakingon a medium that lacked either histidine or phenylalanine. Thefollowing results were obtained:It was found that hisE is 4 minutes away from pabB. The gene pheA was shown to be 17 minutes from pabB. Draw a genetic map describing the locations of all three genes.
a. Bacteriophage P22 was used in generalized transduction experiments to infect the Salmonella typhimurium donor strains described in the table below. The resulting phage lysates were then used to infect the S. typhimurium recipient strains listed in the table. In each cross, a phenotype was selected for one of the three genetic markers studied (str, aceA, thrA), and then replicates were performed to select the corresponding recombinants for the other two markers. The results are given in the following table: Recipient strain Selected phenotype Selected recombinants Donor strain str thrA aceAt thrA str aceA+ strs thrA+ aceA thrA+ str aceA Str Ace+ Str ThrA ThrA+ ThrA ThrA+ Ace Ace+ str: gene involved in streptomycin resistance, aceA: gene involved in the use of acetate as a carbon source, thrA: gene involved in the biosynthesis of threonine. Number 60 40 95 5 10 90 What are the selective media used in these three transduction experiments, on the one hand to obtain the selected…