Bacterial Transduction

9 Key excerpts on "Bacterial Transduction"

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  Microbiology and Nanobiology: Advancing Frontiers

  • Kumar, Har Darshan(Authors)
  • 2021(Publication Date)
  • Daya Publishing House

    (Publisher)

  Refinement through the horizontal sharing of genetic innovations probably triggered an explosion of genetic novelty, until the level of complexity warranted a transition to the current era of vertical evolution (see This ebook is exclusively for this university only. Cannot be resold/distributed. Frigaard et al ., 2006; Vetsigian et al ., 2006). Gene Transfer Among Bacteria in Natural Environments Gene transfer among bacteria in nature can occur by three chief mechanisms: (1) transformation, in which extracellular DNA is taken up by recipient bacteria; (2) conjugation, in which genetic material is transferred from one bacterium to another by cell-to-cell contact: and (3) transduction, in which the transfer of genetic information between bacteria is mediated by bacteriophages. Other possible mechanisms include capsduction by a small phage–like structure (Joset and Guespin–Michel, 1993), protoplast fusion (Matsushima and Baltz, 1986), and transposition (Berg, 1989). Transformation Transformation can be divided into natural transformation and artificial transformation. In natural transformation, recipient bacteria develop a physiological state of competence and actively take up and incorporate extracellular DNA into their genetic information. This seems to occur only in bacteria, but recombinant DNA technology (artificial transformation) can be used with both prokaryotic and eukaryotic cells. Natural transformation (usually referred to as “transformation”) can be distinguished experimentally from conjugation and transduction by its sensitivity to nucleases of DNA ( e.g. , DNase). In as much as gene transfer by transformation occurs via extracellular DNA, DNase can degrade the DNA and prevent transformation. In contrast, during transduction, transducing DNA is protected by the protein coat (capsid) of the phage and is never exposed extracellularly to DNase.

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  Advanced Molecular Biology

  A Concise Reference

  • Richard Twyman(Author)
  • 2018(Publication Date)
  • Garland Science

    (Publisher)

  Chapter 10

  Gene Transfer in Bacteria

  Fundamental concepts and definitions

  • Gene transfer describes the introduction of genetic information into a cell from an exogenous source (ultimately, another cell). This process occurs naturally in both bacteria and eukaryotes, and may be termed horizontal or lateral genetic transmission to distinguish it from the transmission of genetic information from parent to offspring, which is vertical genetic transmission.
  • Intraspecific gene transfer facilitates genetic mixing in asexual species and thus mimics the effects of sexual reproduction. Such parasexual exchange mechanisms have been exploited to map prokaryote genomes analogously to meiotic mapping (q.v.) in eukaryotes. Interspecific gene transfer can also occur, and is a natural mechanism of transgenesis (q.v.). Interspecific gene transfer is an important evolutionary process and has been responsible for some of the most fundamental evolutionary events (e.g. the endosymbiont origin of eukaryotic organelles) as well as facilitating specific interactions between bacteria and eukaryotes (e.g. tumor-induction by Agrobacterium tumorfaciens; q.v. Ti plasmid).
  • The source of the transferred information is the donor and the genetic information transferred is the exogenote (exogenous genome, usually only a fragment of the donor genome). The target of the gene transfer, the recipient, possesses the endogenote (endogenous genome). If the exogenote is homologous to part of the endogenote, gene transfer will make the recipient cell partially diploid (a merozygote), in which case recombination can occur, which may involve allele replacement (marker exchange).
  • There are four major mechanisms of gene transfer in bacteria: cell fusion, conjugation, transformation and transduction (Table 10.1 ).

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  Biochemistry and its application

  • Papita H Gourkhede(Author)
  • 2023(Publication Date)
  • Arcler Press

    (Publisher)

  Unless it becomes part of a replicon by recombination, a portion of chromosomal DNA from a donor bacterium normally cannot reproduce in the receiving bacterium. Traditionally, the characterization of the “transforming principle” of S. pneumoniae offered the first direct proof that DNA is the genetic material. 3.3. TRANSDUCTION Bacteriophages operate as vectors in transduction, introducing DNA from donor bacteria into recipient bacteria via infection. A tiny percentage of the virions generated during lytic growth by some phages, known as generalized transducing phages, are aberrant and include a random piece of the bacterial genome instead of phage DNA. Each transducing phage carries a unique collection of closely connected genes that represent a small portion of the bacterial genome. Generalized transduction is mediated by populations of such phages because each region of the bacterial genome has roughly the same likelihood of being transmitted from donor to recipient bacterium. Figure 3.1. Transduction pathways. Source: Image by Wikimedia Biochemistry and its Application 68 If a generalized transducing phage infects a recipient cell, the donor genes that have been transmitted are expressed. Abortive transduction is defined as the transitory expression of one or more donor genes without the generation of recombinant offspring, whereas full transduction is defined by the development of stable recombinants that inherit donor genes and maintain the capacity to express them. The donor DNA fragment does not replicate in abortive transduction, and only one bacterium from the initial transductant has the donor DNA fragment. After each generation of bacterial development, the donor gene products get progressively diluted in every other progeny until the donor phenotype could no longer be reproduced.

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  Microbiology

  Principles and Explorations

  • Jacquelyn G. Black, Laura J. Black(Authors)
  • 2018(Publication Date)
  • Wiley

    (Publisher)

  Such an F′ plasmid may then be transferred by conjugation to an F– cell. The recipient cell will then have two copies of some genes—one on its chromosome and one on the plasmid. © John Wiley and Sons, Inc. © John Wiley and Sons, Inc. 216 CHAPTER 9 Gene Transfer and Genetic Engineering transfer into species other than their own kind. Those that can are said to be promiscuous. Sometimes the species are only distantly related; in other cases, transfer even occurs into eukaryotic cells! Obviously this has important impli- cations for health and evolution. Some Gram-positive bacteria have self-transmissible plasmids that do not form F pili. Instead, bacteria lack- ing these plasmids secrete peptide compounds, which stimulate nearby bacteria that do contain the plasmids to mate with them. Once a bacterium acquires the plasmid, it stops producing the attracting peptide for it. This is a neat conservation of energy. However, these cells will still secrete other peptides that will serve as mating lures for other plasmids they have not yet acquired. GENE TRANSFER MECHANISMS COMPARED The most fundamental differences among the major types of transfers of genetic information concern the quantity of DNA transferred and the mechanism by which the trans- fer takes place. In transformation, less than 1% of the DNA in one bacterial cell is transferred to another, and the transfer involves only chromosomal DNA. In transduction, the quantity of DNA transferred var- ies from a few genes to large fragments of the chromosome, and a bacteriophage is always involved in the transfer. In specialized transduction, the phage inserts into a bacte- rial chromosome and carries a few host genes with it when it separates. In generalized transduction, the phage causes fragmentation of the bacterial chromosome; some of the fragments are accidentally packed into viruses as they are assembled. In conjugation, the quantity of DNA transferred is highly variable, depending on the mechanism.

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  Molecular Biology

  • David P. Clark(Author)
  • 2009(Publication Date)
  • Academic Cell

    (Publisher)

  When a virus succeeds in infecting a bacterial cell it manufactures more virus particles, each of which should contain a new copy of the virus genome. Occasionally, viruses make mistakes in packaging DNA, and fragments of bacterial DNA get packaged into the virus particle. From the viewpoint of the virus, this results in a defective particle. Nonetheless, such a virus particle, carrying bacterial DNA, may infect another bacterial cell. If so, instead of injecting viral genes, it injects DNA from the previous bacterial victim. This mode of gene transfer is known as transduction.

  Viruses may pick up fragments of host DNA and carry them to another host cell.

  Bacterial geneticists routinely carry out gene transfer between different but related strains of bacteria by transduction using bacterial viruses, or bacteriophages (phages for short). If the bacterial strains are closely related the incoming DNA is accepted as “friendly” and is not destroyed by restriction. In practice, transduction is the simplest way to replace a few genes of one bacterial strain with those of a close relative.

  To perform transduction, a bacteriophage is grown on a culture of the donor bacterial strain. These bacteria are destroyed by the phage, leaving behind only DNA fragments that carry some of their genes and are packaged inside phage particles. If required, this phage sample can be stored in the fridge for weeks or months before use. Later, the phage are mixed with a recipient bacterial strain and the DNA is injected. Most recipients get genuine phage DNA and are killed. However, others get donor bacterial DNA and are successfully transduced (Fig. 18.08 ).

  Figure 18.08 Principle of TransductionOccasionally, when a phage infects a bacterium, one of the virus coats will be packaged with host bacterial DNA. The defective phage particle still infects a nearby cell where it injects the bacterial DNA. This cell will survive since it is not injected with viral DNA. The incoming DNA may be recombined with the host chromosome, thus this cell may gain new genetic information.

  Generalized Transduction

  There are two distinct types of transduction. In generalized transduction fragments of bacterial DNA are packaged more or less at random in the phage particles. This is the case for bacteriophage P1 as described above (Fig. 18.08 ). Consequently all genes have roughly the same chance of being transferred. In specialized transduction

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  Microbial Process Development

  • H W Doelle(Author)
  • 1994(Publication Date)
  • WSPC

    (Publisher)

  Bacterial genes are incorporated into a phage capsid because of errors made during the virus l i f e cycle. The defective virion, referred to as a transducing particle, contain DNA from the bacterial genome replacing part or a l l of the normal complement of phage DNA. The virion containing these genes the injects them into another bacterium, completing the transfer. Two types of transducing particles and therefore two types of transduction exist: the generalized or non-specific transduction mediates the exchange of any bacterial gene, whereas the restricted or specialized transduction mediates the exchange of only a limited number of specific genes. Most transducing phages are capable of mediating only one, but a limited number are capable of mediating both types of transduction. 4.3.1 Generalized or non-specialized transduction Generalized transduction occurs during the lytic cycle of virulent and temperate phages and can transfer any part of the bacterial genome. When the viral chromosomes are packaged into the protein capsids, random fragments of the partially degraded bacterial chromosome also may be packaged Bacterial Genetics 83 by mistake. The quantity of b a c t e r i a l DNA carried depends on the size of the capsid. For example, the P22 phage of Sal-monella typhymurium usually carries about 1% of the bacteri-a l genome, whereas PI phages of E.coli i s able to carry 2¬ 2.5% of the genome. The so formed virus i n j e c t s the DNA into another b a c t e r i a l c e l l without i n i t i a t i n g a l y t i c cycle. Such phage i s a simple c a r r i e r of genetic information from one bacterium to another and i s referred to as a generalised transducing p a r t i c l e . Since phage lysates used to mediate generalized trans-duction contain infectious v i r i o n s , precautions must be taken to prevent the k i l l i n g of transduced c e l l s by these v i r i o n s .

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  Fundamental Bacterial Genetics

  • Nancy Trun, Janine Trempy(Authors)
  • 2009(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  The techniques developed using generalized transduction provide one of the major advantages of working with bacteria. Transduction 141 Further reading Masters, M. 1996. Generalized transduction. In Escherichia coli and Salmonella typhimurium: Cellular and Molecular Biology, 2nd edn., eds. F.C. Neidhardt, R. Curtiss III, J.L. Ingraham, E.C.C. Lin, K.B. Low, B. Hagasanik, W.S. Rexnikoff, M. Riley, M. Schaechter, and H.E. Umbarger, pp. 2421–41. Washington, DC: ASM Press. Weisberg, R. Specialized transduction. In Escherichia coli and Salmonella typhimurium: Cellular and Molecular Biology, 2nd edn., eds. F.C. Neidhardt, R. Curtiss III, J.L. Ingraham, E.C.C. Lin, K.B. Low, B. Hagasanik, W.S. Rexnikoff, M. Riley, M. Schaechter, and H.E. Umbarger, pp. 2442–8. Washington, DC: ASM Press. Zinder, N.D. 1992. Forty years ago: the discovery of Bacterial Transduction. Genetics, 132: 291–4. Zinder, N.D. and Lederberg, J. 1952. Genetic exchange in Salmonella. J. Bacteriol., 64: 679–99. Study questions 1 What type of transducing particles carry the same piece of DNA in every phage particle? Different DNA in different transducing particles? 2 How does P1 package chromosomal DNA? 3 What is coinheritance? 4 What is the difference between a screen and a selection? How many cells can be surveyed in a screen? A selection? Which one is more powerful? 5 What are merodiploids and why are they useful? 6 What information can be obtained in a three-factor cross? 7 Can you order genes using a two-factor cross? Why or why not? 8 Devise a strategy for isolating an amber mutation in ftsZ, an essential gene required for cell division. 9 What type of transducing phage can be used to move a mutation from a plasmid to the chromosome? Diagram how this happens. Chapter 9 Natural plasmids Plasmids are pieces of DNA that exist separate from the chromosome (Fig. 9.1). They contain an origin for DNA replication and, as such, replicate independently from the chromosome.

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  Principles of Genetics

  • D. Peter Snustad, Michael J. Simmons(Authors)
  • 2016(Publication Date)
  • Wiley

    (Publisher)

  In specialized transduction, a recombination event occurs between the host chromosome and the phage chromosome, producing a phage chromosome that contains a piece of bacterial DNA. Phage particles that contain bacterial DNA are called transducing particles. Generalized transducing particles contain only bacterial DNA. Specialized transducing particles always contain both phage and bacterial DNA. Generalized Transduction Generalized transducing phages can transport any bacterial gene from one cell to another—thus, the name generalized transduction. The best known generalized transducing phages are P22 in S. typhimurium and P1 in E. coli. Only about 1 to 2 percent of the phage particles produced by bacteria infected with P22 or P1 contain bacterial DNA, and only about 1 to 2 percent of the transferred DNA is incorporated into the chromosome of the recipient cell by recombination. Thus, the process is quite inefficient; the frequency of transduction for any given bacterial gene is about 1 per 10 6 phage particles. Specialized Transduction Specialized transduction is characteristic of viruses that transfer only certain genes between bacteria. Bacteriophage lambda (λ) is the best-known specialized transduc- ing phage; λ can carry only two sets of genes from one E. coli cell to another: the gal genes required for the utilization of galactose as an energy source or the bio genes, which are essential for the synthesis of biotin. Earlier in this chapter, we discussed the site-specific insertion of the λ chromosome into the E. coli chromo- some to establish a lysogenic state (see Bacteriophage Lambda). The insertion site is between the gal genes and the bio genes on the E. coli chromosome (see Figure 8.5). The proximity of these genes to the λ insertion site explains why they can be carried from one cell to another by a λ bacteriophage.

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  Molecular Genetic Modification of Eucaryotes

  • Irwin Rubenstein, Ronald L. Phillips, Charles E. Green, Irwin Rubenstein, Ronald L. Phillips, Charles E. Green(Authors)
  • 2013(Publication Date)
  • Academic Press

    (Publisher)

  Transducing Viruses and Viral Integration: Techniques for Genetic Modification Kazunori Shimada, Robert A. Weisberg, and Max E. Gottesman The purpose of this article is to review the current status of lambda-pro-moted transduction, with a view towards using transduction as a means of obtaining specific bacterial genes in high yields on a convenient virus vector. THE INTEGRATION AND EXCISION OF BACTERIOPHAGE LAMBDA The isolation of transducing lambda (λ) phage, that is phage which carry bacterial DNA covalently linked to the viral genome, usually requires integra-tion of the phage DNA into the host chromosome. Integration results from reci-procal recombination between lambda DNA and E. coli DNA. The integrated phage genome is covalently linked to the host chromosome (Gottesman and Weisberg, 1971). Lambda normally integrates at only one site or locus on the E. coli genome termed att B. This site is located between the galactose (gal) and biotin (bio) opérons. The distinctive features of the base sequence of the att B site responsi-ble for this specificity are not known. What is clear is that there is little homo-logy between the base sequence of the DNA at the att B site and lambda DNA. Attachment involves the recognition of the specific DNA base sequences rather than simply the recognition of complementary base sequences. This is consistent with the observation that phage DNA integration requires a protein for integra-tion (termed Int) encoded for by the phage genome. The Int protein does not promote general recombination, that is recombination between homologous DNA molecules that do not contain attachment sites, nor do the bacterial host general recombination functions promote normal lambda DNA integration. The excision of prophage lambda from the E. coli chromosome is an effi-cient recombination process that requires two proteins encoded in the phage genome, Int and an excision protein (termed Xis) (Echols, 1970).

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