Specialized transduction by temperate bacteriophage. This chapter describes methods that have been found. Ap biology study guide key chapter 18 interactive questions. Generalized transduction vs specialized transduction lecture explains about the difference between generalized and specialized transduction. Generalized transduction is initiated by a lysogenic bacteriophage. Generalized transduction refers to the mispackaging of bacterial dna into the phage. Bacteriophages benefit from generalized transduction plos.
We would like to show you a description here but the site wont allow us. What is the difference between a virulent phage and a. Generalized transduction by phage p22 in salmonella. It is typical of temperate phages to be latent or inactive within the cell. Specialized transduction by temperate phage specialized transduction by temperate phage hd explainationanimation3d transduction is the process by which dna is transferred from one bacterium to another by a virus. Generalized transduction occurs during the lytic cycle of virulent or temperate phages. Specialized transduction by phage p22 is different from, and less restricted than, the well characterized specialized transduction by phage lambda, due to differences in the phage dna packaging mechanism. B a piece if injected dna remains separate from the host dna. Mcb 3020 exam 3 practice exam questions and study guide. Specialized transduction 2000 written by gary roberts, edited by timothy paustian, university of wisconinsmadison. The role of temperate bacteriophages in bacterial infection. Fox department of biology massachusetts institute of technology cambridge, mass.
Generally, p22 exists in lysogenic state in la22 strain of s. In some occasions, dna from a specific region of the host chromosome is integrated directly into the virus genomeusually replacing some viral genes. Generalized transduction, discovered in salmonella phage p22, was the first. Transduction is the process where bacterial dna is transferred by bacteriophages viruses into bacterial genome. Modelling phagebacteria interactions driving predation. We employed the splitstree, rdp4 and simplot software packages in. The model was implemented in vensim ple plus software ventana systems inc. The role of temperate phage in disease situations 87 is thus becoming increasingly recognised. Virology 70, 221222 1976 specialized transduction of reca by bacteriophage lambda kevin mcentee department of biophysics and theoretical biology, university of chicago, chicago, illinois 60637 accepted october 22, 1975 the isolation of a plaqueforming \ phage carrying the reca locus otescherichia coli is reported. Generalized transduction vs specialized transduction youtube. Generalized transduction see below occurs in both cycles during the lytic stage, while specialized transduction see.
The resulting defective transducing phage temperate phage particles now have bacterial dna as a part of genome. Bacteriophages as vehicles for antibiotic resistance genes. Atemperate phage can integrate its genome into its host bacteriums chromosome, becoming a lysogen known as a prophage. The information takes the form of dna that can be used to perform new functions once in the second cell. Biol 230 lecture guide animation of specialized transduction in. Modeling the infection dynamics of bacteriophages in enteric. See more ideas about physiology, biology and ap biology. About accessscience accessscience provides the most accurate and trustworthy scientific information available. But specialized transduction is an extremely efficient gene transfer mechanism. Hersheychase experiment animation hiv infection cycle animation hiv replication animation hiv treatment animation lambda phage replication cycle animation malaria animation prion animation releasing enveloped virions animation replication cycle of a retrovirus animation specialized transduction by temperate phage animation transduction. Correctly identify the steps that lead to production of both normal temperate phage and defective phage particles carrying host genetic material for specialized transduction events. Specialized transduction occurs in temperate phages when prophage excision.
The temperate bacteriophage p22 mediates both generalized and specialized transduction in salmonella typhimurium. A a piece of dna is injected into a bacterium, and it then forms a plasmid. Shortly thereafter, specialized transduction was discovered using the bacteriophage lambda 2346. The genes that get transferred donor genes depend on where the phage genome is located on the chromosome. Modeling the infection dynamics of bacteriophages in. Correctly identify the steps that lead to producti. Specialized transduction lysogenic phagelysogenic phage. Animal viruses may be grown in cell culture, embryonated eggs fig. We have continued to study the role of transduction in phage host interactions and propose here that infection of a bacterial cell by a temperate phage and a transducing particle can increase fitness of both by allowing the host cell to acquire adaptive genes, whose benefits are shared with the prophage.
With reference to genetic transduction not specialized transduction, he further points out that. As interest in lytic phages as antimicrobial therapies or as treatments to reduce environmental contamination with pathogenic bacteria has increased, so has the need to determine if the use of lytic phages may lead to dissemination of virulence factors through generalized transduction, as occurs with temperate phages. The process in which a bacterium is infected by a temperate phage is called lysogeny. The bacteriophage inserts its genome into the bacteriums nucleoid to. In lytic phase, the phage injects its dna into the bacteria. In transduction, dna is transferred from one cell to another through the agency of viruses.
Specialized transduction specialized transduction is the process by which a restricted set of bacterial genes is transferred to another bacterium. Bacteriophages benefit from generalized transduction. Lysogeny and transduction describes a type of phage host interaction and a method of bacterial gene transfer procaryotic sex, respectively. The term specialized gene transduction is used when the prophage. There are two phases of transduction the lytic and the lysogenic phase. It also refers to the process whereby foreign dna is introduced into another cell via a viral vector. After penetration a phage genome multiplies within the cell b, c, the bacterial chromosome is fragmented into pieces c. Outline of generalized transduction is given in fig. Genetic transduction by phages and chromosomal islands. Gene transfer in eukaryotes by transposable elements, the genetic vectors, is a process similar to prokaryotic transduction. An integrated phage excises, bringing with it a piece of the. Phage that can either multiply via the lytic cycle or enter a quiescent state in the bacterial cell. Specialized transduction is treated in detail in chapter 1 of this volume. Specialized transduction by phage p22 is different from, and less restricted than, the well characterized specialized transduction by phage lambda, due to differences in the phage.
Lambda phage has also been of major importance in the study of specialized transduction. We show here that bacteria and generalized transducing phages cooperate. Lysogenic cell immune to reinfection by same phage 2. Generalised transduction is mediated by lytic phages. An ebook reader can be a software application for use on a computer such as. Specialized transduction of reca by bacteriophage lambda. Sitespecific recombination integration site is known as att p, in e. Recognized as an awardwinning gateway to scientific knowledge, accessscience is an amazing online resource that contains highquality reference material written specifically for students. Generalized transduction is initiated during lytic cycle of a virulent bacteriophage. In specialized transduction the phage inserts its genome at the specific site.
Bacteriophage p22mediated specialized transduction in. Cartoon depicting lytic, lysogenic, and pseudolysogenic phagebac. Correctly identify the steps that lead to production of both normal temperate phage and defective. The enteric phages appear to be mostly temperate, and the majority of virions in feces. A temperate phage is a bacteriophage that infects bacteria, however, a temperate phage has good temperament, and it resides and replicates within the lysogenic bacterial cell. The integration reaction att b x att p is mediated by the proteins integrase int. Lambda phage can be manipulated and used as an anticancer vaccine, nanoparticle, targeting human aspartyl asparaginyl. View the animation below, then complete the quiz to test your knowledge of the concept. In generalized transduction, virtually any genetic marker can be transferred from donor to recipient cell but it occurs at a low frequency. Types of bacteriophage lytic or virulent phage that multiply within the host cell, lyse the cell and release progeny phage e. In the lytic pathway, phage inject their dna into the bacterium, take over the cells replication. Generalized transduction is mediated by temperate phages that employ. Hgt may take place in both lytic and temperate phage with the form of generalized transduction, whereas the events of specialized transduction and lysogenic conversion are restricted only to. Generalized transduction implicates the transfer of any portion of the donor genome to the recipient cell by either a lytic or lysogenic temperate phage, whereas specialized transduction involves only temperate phages, in which a few specific donor genes can be transferred to the recipient cell.
In virology, temperate refers to the life cycle some phages are able to perform. Generalized transduction vs specialized transduction duration. Specialized transduction by temperate phage hd animation youtube. Molecular origin of transducing dna judith ebeltsipisf, david botstmn and mattbiob s.
Keceived march 1972 p22, a temperate phage which grows on salmonella typhimurium, is capable of. What type of phage and reproductive cycle would cause specialized transduction. Transduction generalized view the animation below, then complete the quiz to test your knowledge of the concept. This flowchart illustrates the mechanism of specialized transduction. Phage life cycles and types of phagemediated transduction. The att sites contain the binding sites for the proteins that mediate lambda recombination. Genetic transfer of host gene by bacteriophage occurs in two waysgeneralized transduction and specialized transduction. Specialized transduction uses animal viruses instead of bacteriophage. A temperate phage that leaves the lysogenic cycle and enters the lytic cycle may carry bacterial genes that were adjacent tote insertion site of the prophage. Other useful data would include better information on the fraction of enteric phages that are temperate and are capable of specialized or generalized transduction, the sizes of the bacterial genome segments that can be transduced, the variation in the burst size and the tp fraction of the burst, the comparative rates of extracellular survival. Summarizing part of the article, norton zinder refers to genetic transduction, and notes that we knew nothing about phage or temperate phage at the time. A temperate bacteriophage adsorbs to a susceptible bacterium and injects its genome. The specialized transducer phage must be a temperate phages, which transduces only the special gene located at its integration site. Specialized transduction occurs when a temperate phage.
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