Chapter 7 recombination in bacteria and their viruses. Small, circular dna molecules that can exist independently of the chromosome 2. Objectives to demonstrate the technical procedure to monitor the conjugational transfer of genetic material from one cell to another. Microbial ecology and role of microorganism in ecosystem. Free class materials on microbial genetics, including a lecture powerpoint, class notes. Liquid, semi solid agar growths are physiologically uniform.
Divide the plate in half and label each half with the respective group name. Between bacterial cells 1 transformation acquisition by incorporation of exogenous or foreign dna. Conjugation transfer of dna by direct contact between a donor cell and recipient cell often requires a sex pilus pulls recipient to the donor. The below mentioned article provides notes on conjugation. The bacterial mating process requires contact between cells. Population of viruses with similar characteristics occupying a particular ecological niche. Identify the types of plasmids that are important creators of genetic variation 2. Conjugation transfer of dna by direct contact between a donor cell and recipient cell often requires a sex pilus pulls recipient to the donor transfer plasmid, sometimes with genomic dna attached to it. Transformation extracellular dna uptake conjugation bacterial mating systems. Mechanisms of genetic variation bellarmine university. We began our introduction to prokaryotic genetics by pointing out that we had been using bacteria and their viruses as experimental organisms to investigate the biochemistry of heredity in prior lectures. In the experiment shown in the figure below, the two.
In accordance with its predecessor, the completely revised and expanded second edition of modern microbial genetics focuses on how bacteria and bacteriophage arrange and rearrange their genetic material through mutation, evolution, and genetic exchange to take optimal advantage of their environment the text is divided into three sections. Revision notes crosscultural psychology indigenous and, module lectures notes. Conjugation gene cloning gene cloning is the incorporation of a. The fertility f factor enables the cell to act as donor. To learn about the various genetic elements involved in bacterial sex and recombination events. Bacterial transformation with recombinant dna for information on the plasmids used in this lab contact ted lee. They were first discovered by anton leeuwenhoek 1676. To explain the term endotoxin in terms of its chemical composition and location in bacterial cells introduction to bacteriology 1. Lecture notes systems microbiology biological engineering. Bacterial cell morphology, staining reactions, classification of bacteria the protoplast is bounded peripherally has a very thin, elastic and semipermeable cytoplasmic membrane a conventional phospholipid bilayer. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Regulation of bacterial gene expression constitutive. At the end of the incubation step 4, vortex, or vigorously shake, the tube for 1 minute to stop the conjugation process.
Conjugation differs from transformation in the fact that in the former physical contact is established between two different strains through a conjugation tube. It can be found in soil, air, water, and living bodies. It is a mechanism of horizontal gene transfer as are transformation and transduction although these two other mechanisms do not involve celltocell. Lecture 15 prokaryotic genetics october 17, 20 introduction. Evolution of sexual reproduction is one of the major milestones in the history of life that actually fuelled this amazing diversity. Monday oct 16 ch 10 brock genetic exchange in bacteria. Bacteriophages can transduce bacterial genes from one cell to another. These methods of gene transfer generate partial diploids that allow study of genes.
Gene exchange in bacteria transfer of dna from one bacterium to another is a common means of gene dispersal. Vortex the tube for 90 seconds at top speed and then transfer 0. Lets delve into microbiology and learn about gene transfer mechanisms. Population of cells derived from a single cell strain. Download and print out the lecture slides, when available, and bring them to class. Microbiology lecture notes and study guides microsoft word 7. Incubation in 37o water bath for proper conjugation o 30 minutes. In this case, a small protuberance, called bud, develops at one end of the cell. Chapter 7 recombination in bacteria and their viruses conjugation transformation transduction. First, we shall consider conjugation, which requires celltocell contact.
The essential feature of the process is that two bacterial cells come together and mate such that a gene transfer occurs between them. Since it comprises most of the contents of course outline on medical bacteriology to nursing, pharmacy and environmental science. Describe the features of the f factor that allow it to 1 transfer itself to a new host cell and 2 integrate into a host cells chromosome 3. General microbiology lecture notes 1 21 0914 studocu. To recognize and discuss the advantages and limitations of the conjugational. In bacterial populations mutations are constantly arising due to errors made during replication.
The bacterial dna lies on sides of integrated phage dna are only carried during induction. Bacterial cell walls differ with regard to thickness and placement of peptidoglycan dense polymer of sugars and amino acids. Bacteria growth and nutrition cell growth is defined as an increase in cell number via binary fission or budding or an increase in cell size volume. Bacterial conjugation animation and quiz from mcgrawhill. It was first reported by lederberg and tatum 1946 in li bacteria. The f factor of donor cell includes the informations of sex pili the number of which varies from 1 to 3. Bacterial conjugation is the transfer of genetic material between bacterial cells by direct celltocell contact or by a bridgelike connection between two cells. Bacterial conjugation is the transfer of genetic material between bacteria through celltocell contact. By shaking the sample nutrients are evenly distributed. Hfr conjugation if f factor plasmid is inserted into host chromosome hfr cell, this will result in the transfer of the entire dna complex. Characteristics a much smaller than the chromosome bacterial conjugation is the bacterial equivalent of sexual reproduction or mating. Many antibiotics target the bacterial cell wall and or proteins involved in its synthesis. Bacteria reproduce by vegetative, asexual and sexual methods. Genetically different cells within a clone viral species.
Bacteria are the simplest, the smallest, and the most successful microorganisms. Bacterial transformation transformation is the process of introduction of derived dna fragments from a donor bacteria into a recipient bacteria. There are special appendages present on bacterial cell surface which are called sex pilus or f pilus which forms the conjugation tube. The best way for students to print out the powerpoint show is to download the pdf version. In the five kingdom classification, they are placed in kingdom monera. Free class materials on microbial genetics, including a lecture.
Reproduction in bacteria vegetative, asexual and sexual. In bacterial populations mutations are constantly arising due to. Systems microbiology monday oct 16 ch 10 brock genetic exchange in bacteria homologous recombinationhomologous recombination transformation transformation plasmids and conjugationplasmids and conjugation transposable elementstransposable elements transduction virus mediatedtransduction virus mediated xchange. A dna molec ule or gene is said to be cloned if it is contained in a vector dna molecule from which the cloned. Characteristics a much smaller than the chromosome pdf bacterial genetics bacteria reproduce by the process of binary fission the chromosome in the mother cell is replicated. Microbial genetics lecture materials from the virtual. It is bacterial conjugation that allows bacteria to transfer drug resistance. Bacterial genetics, lectures 3 st replication dna regulation change mutation. Bacterial conjugation is in fact the simple exchange of genetic material and information from one bacteria to another. Conjugation was the first extensively studied method of gene transfer. Microbiology 2421 lecture notes microbial genetics and. Text book on medical bacteriology for medical laboratory technology students are not available as need, so this lecture note will alleviate the acute shortage of text books and reference materials on medical bacteriology. In transformation, dna from the environment can enter bacterial cells and integrate into the chromosome.
Recombination in bacteria transformation, transduction and. Some bacteria can cause diseases for human, animals and plants. Cell to cell union occurs between two bacterial cells and genetic material dna of one bacterial cell goes to another cell lengthwise through conjugation tube which is formed by sex pili. Not every eukaryotic cell exhibits all features shown, e. Since plasmid replicon type determines inc group, the terms inc and rep type were interchangeably used to describe plasmid types. Bacterial plasmids plasmids are defined as double stranded, extrachromosomal genetic elements that replicate. Bacterial conjugation an introduction to genetic analysis. Medical microbiology and immunology 1 bio1104 uploaded by. Conjugation cell to cell interaction, unidirectional from.
Genetic variability essential o survival of the species diploid eukaryotes o crossing over o meiosis haploid prokaryotes o transduction o transformation o conjugation. Microbiology 2421 lecture notes microbial genetics and biotechnology. In conjugation, bacteria transfer plasmid or chromosomal dna to another bacterial cell through a bridge between the cells called a pilus. Between bacterial cells 1 transformation acquisition by incorporation of exogenous or foreign dna 2 transduction transfer from one bacterium to another by bacteriophage 3 conjugation quasi sexual exchance. Find materials for this course in the pages linked along the left.
But think of bacteria, simple in structure, no true sexual reproduction, still present everywhere in the planet from our intestine to deep thermal vents even in extreme temperatures of hot sulphur springs archae bacteria. Outside, and closely covering this, lies the rigid, supporting cell wall. Conjugation cell to cell interaction, unidirectional from male to female different conjugative plasmids. Organism whose cells lack a membrane enclosed nucleus b.
This section and subsequent sections describe the discovery of gene transfer in bacteria and explain several types of gene transfer and their use in bacterial genetics. Be able to explain the concepts for each diagram presented in your own words. Conjugation transformation transduction assignment 4 5% background information of the system briefly define each term describe how each process occur in bacteria explain how their genetic materials are exchanged you may use suitable figures and sketches to support your answer. Bacterial conjugation was first postulated in the 1940s by joshua lederberg and edward tatum. For example, lateral transfer is responsible for the spread drug resistance determinants between bacterial species. Centrifugation dna pellet formation o removal of supernatant tsb broth. The second section is devoted to how microorganisms interact with their environment, including chapters on sporulation and stress shock, and the final section contains the latest information on classic exchange mechanisms such as transformation and conjugation. Initially, inc typing relied on introduction of a plasmid into a strain carrying another plasmid and determining whether both plasmids were stably maintained in the progeny. In conjugation dna is transferred only from the donor to the recipient with no. It has a big effect on bacterial evolution, and tremendous practical implications. For all three process, the transferred dna must be stably incorporated into the genetic material of the recipient bacterium.
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