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T2 Phage
Enterobacteria phage T2 is a virus that infects and kills '' E. coli''. It is in the genus '' Tequatrovirus'', and the family ''Myoviridae''. Its genome consists of linear double-stranded DNA, with repeats at either end. The phage is covered by a protective protein coat. The T2 phage can quickly turn an ''E. coli'' cell into a T2-producing factory that releases phages when the cell ruptures. Experiments conducted in 1952 by Alfred Hershey and Martha Chase demonstrated how the DNA of viruses is injected into the bacterial cells, while most of the viral proteins remain outside. The injected DNA molecules cause the bacterial cells to produce more viral DNA and proteins. These discoveries supported that DNA, rather than proteins, is the hereditary material. The first phages that were studied in detail included seven that commonly infect ''E. coli.'' They were named Type 1 (T1), Type 2 (T2), etc., for easy reference; however, due to structural similarities between the T2, T4, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enterobacteria Phage T2 Transmission Electron Micrograph
Enterobacteriaceae is a large family of Gram-negative bacteria. It was first proposed by Rahn in 1936, and now includes over 30 genera and more than 100 species. Its classification above the level of family is still a subject of debate, but one classification places it in the order Enterobacterales of the class Gammaproteobacteria in the phylum Pseudomonadota. In 2016, the description and members of this family were emended based on comparative genomic analyses by Adeolu et al. Enterobacteriaceae includes, along with many harmless symbionts, many of the more familiar pathogens, such as '' Salmonella'', ''Escherichia coli'', ''Klebsiella'', and ''Shigella''. Other disease-causing bacteria in this family include ''Enterobacter'' and '' Citrobacter''. Members of the Enterobacteriaceae can be trivially referred to as enterobacteria or "enteric bacteria",as several members live in the intestines of animals. In fact, the etymology of the family is enterobacterium with the suffix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteriophage
A bacteriophage (), also known informally as a ''phage'' (), is a duplodnaviria virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν ('), meaning "to devour". Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as four genes (e.g. MS2) and as many as hundreds of genes. Phages replicate within the bacterium following the injection of their genome into its cytoplasm. Bacteriophages are among the most common and diverse entities in the biosphere. Bacteriophages are ubiquitous viruses, found wherever bacteria exist. It is estimated there are more than 1031 bacteriophages on the planet, more than every other organism on Earth, including bacteria, combined. Viruses are the most abundant biological entity in the water column of the world's oceans, and the second largest component of biom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escherichia Coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escherichia'' that is commonly found in the lower intestine of warm-blooded organisms. Most ''E. coli'' strains are harmless, but some serotypes ( EPEC, ETEC etc.) can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains do not cause disease in humans and are part of the normal microbiota of the gut; such strains are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of ''E. coli'' benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between ''E. col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tequatrovirus
''Tequatrovirus'' is a genus of viruses in the order ''Caudovirales'', in the family ''Myoviridae'', in the subfamily '' Tevenvirinae''. Gram-negative bacteria serve as the natural host, with transmission achieved through passive diffusion. There are 75 species in this genus. Taxonomy The following species are assigned to the genus: *'' Citrobacter virus CrRp10'' *'' Citrobacter virus PhiZZ6'' *'' Citrobacter virus PhiZZ23'' *'' Enterobacteria virus Aplg8'' *'' Enterobacteria virus GiZh'' *'' Enterobacteria virus IME340'' *'' Enterobacteria virus Kha5h'' *'' Enterobacteria virus RB18'' *'' Enterobacteria virus RB27'' *'' Enterobacteria virus T6'' *'' Escherichia virus AR1'' *'' Escherichia virus AREG1'' *'' Escherichia virus C40'' *'' Escherichia virus CF2'' *'' Escherichia virus DalCa'' *'' Escherichia virus E112'' *'' Escherichia virus EC121'' *'' Escherichia virus ECML134'' *'' Escherichia virus EcNP1'' *'' Escherichia virus ECO4'' *'' Escherichia virus EcoMF1'' *'' Escheric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myoviridae
''Myoviridae'' is a family of bacteriophages in the order ''Caudovirales''. Bacteria and archaea serve as natural hosts. There are 625 species in this family, assigned to eight subfamilies and 217 genera. Subdivisions The subfamily ''Tevenvirinae'' (synonym: ''Tequatrovirinae'') is named after its type species ''Enterobacteria phage T4''. Members of this subfamily are morphologically indistinguishable and have moderately elongated heads of about 110 nanometers (nm) in length, 114 nm long tails with a collar, base plates with short spikes and six long kinked tail fibers. The genera within this subfamily are divided on the basis of head morphology with the genus ''Tequatrovirus'' (Provisional name: ''T4virus'') having a head length of 137 nm and those in the genus ''Schizot4virus'' being 111 nm in length. Within the genera on the basis of protein homology the species have been divided into a number of groups. The subfamily ''Peduovirinae'' have virions with heads of 6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hershey–Chase Experiment
The Hershey–Chase experiments were a series of experiments conducted in 1952 by Alfred Hershey and Martha Chase that helped to confirm that DNA is genetic material. While DNA had been known to biologists since 1869, many scientists still assumed at the time that proteins carried the information for inheritance because DNA appeared to be an inert molecule, and, since it is located in the nucleus, its role was considered to be phosphorus storage. In their experiments, Hershey and Chase showed that when bacteriophages, which are composed of DNA and protein, infect bacteria, their DNA enters the host bacterial cell, but most of their protein does not. Hershey and Chase and subsequent discoveries all served to prove that DNA is the hereditary material. Hershey shared the 1969 Nobel Prize in Physiology or Medicine with Max Delbrück and Salvador Luria for their "discoveries concerning the genetic structure of viruses". Historical background In the early twentieth century, biolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfred Hershey
Alfred Day Hershey (December 4, 1908 – May 22, 1997) was an American Nobel Prize–winning bacteriologist and geneticist. He was born in Owosso, Michigan and received his B.S. in chemistry at Michigan State University in 1930 and his Ph.D. in bacteriology in 1934, taking a position shortly thereafter at the Department of Bacteriology at Washington University in St. Louis. He began performing experiments with bacteriophages with Italian-American Salvador Luria, German Max Delbrück, and observed that when two different strains of bacteriophage have infected the same bacteria, the two viruses may exchange genetic information. He moved with his research partner Martha Chase to Laurel Hollow, New York, in 1950 to join the Carnegie Institution of Washington's Department of Genetics, where he and Martha Chase performed the famous Hershey–Chase experiment in 1952. This experiment provided additional evidence that DNA, not protein, was the genetic material of life. Notable post ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martha Chase
Martha Cowles Chase (November 30, 1927 – August 8, 2003), also known as Martha C. Epstein, was an American geneticist who in 1952, with Alfred Hershey, experimentally helped to confirm that DNA rather than protein is the genetic material of life. Early life and college education Chase was born in 1927 in Cleveland, Ohio. Her father was a Western Reserve University Science Instructor and she grew up with her family in Cleveland Heights, Ohio. After graduating from Cleveland Heights High School, she received a bachelor's degree from the College of Wooster in 1950, then worked as a research assistant before returning to school in 1959 and receiving a PhD in Microbiology from the University of Southern California in 1964. Research and later life In 1950, Chase began working as a research assistant at Cold Spring Harbor Laboratory in the laboratory of bacteriologist and geneticist Alfred Hershey. In 1952, she and Hershey performed the Hershey–Chase experiment, which helpe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-even Bacteriophages
Escherichia virus T4 is a species of bacteriophages that infect ''Escherichia coli'' bacteria. It is a double-stranded DNA virus in the subfamily '' Tevenvirinae'' from the family Myoviridae. T4 is capable of undergoing only a lytic lifecycle and not the lysogenic lifecycle. The species was formerly named T-even bacteriophage, a name which also encompasses, among other strains (or isolates), Enterobacteria phage T2, Enterobacteria phage T4 and Enterobacteria phage T6. Use in research Dating back to the 1940s and continuing today, T-even phages are considered the best studied model organisms. Model organisms are usually required to be simple with as few as five genes. Yet, T-even phages are in fact among the largest and highest complexity virus, in which these phage's genetic information is made up of around 300 genes. Coincident with their complexity, T-even viruses were found to have the unusual base hydroxymethylcytosine (HMC) in place of the nucleic acid base cytosin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lytic Cycle
The lytic cycle ( ) is one of the two cycles of viral reproduction (referring to bacterial viruses or bacteriophages), the other being the lysogenic cycle. The lytic cycle results in the destruction of the infected cell and its membrane. Bacteriophages that only use the lytic cycle are called virulent phages (in contrast to temperate phages). In the lytic cycle, the viral DNA exists as a separate free floating molecule within the bacterial cell, and replicates separately from the host bacterial DNA, whereas in the lysogenic cycle, the viral DNA is located within the host DNA. This is the key difference between the lytic and lysogenic (bacterio)phage cycles. However, in both cases the virus/phage replicates using the host DNA machinery. Description The lytic cycle, which is also commonly referred to as the "reproductive cycle" of the bacteriophage, is a six-stage cycle. The six stages are: attachment, penetration, transcription, biosynthesis, maturation, and lysis. # Attachment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
