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Lederbergvirus P22
Salmonella virus P22 is a bacterial virus (bacteriophage) that infects ''Salmonella typhimurium''. Like many phages, it has been used in molecular biology to induce mutations in cultured bacteria and to introduce foreign genetic material. P22 has been used in generalized transduction and is an important tool for investigating ''Salmonella'' genetics. Morphology, classification and relatives P22 shares many similarities in genetic structure and regulation with bacteriophage λ. It is a temperate double stranded DNA phage as well as a lambdoid phage since it carries control of gene expression regions and early operons similar to those of bacteriophage λ. However, the genes which encode proteins that build the virion are different from those of bacteriophage λ. P22 has a 60 nm diameter icosahedral (T=7) virion head and a short tail. This virion morphology puts P22 in the formal ''Podoviridae'' group. Traditionally, P22 is associated with viruses with similar geno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteriophage
A bacteriophage (), also known informally as a phage (), is a virus that infects and replicates within bacteria. The term is derived . Bacteriophages are composed of proteins that Capsid, 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. Bacteriophage MS2, 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 biomass after prokaryotes, where up to 9x108 virus, virions per millilitre have b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infection
An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an Disease#Terminology, illness resulting from an infection. Infections can be caused by a wide range of pathogens, most prominently pathogenic bacteria, bacteria and viruses. Hosts can fight infections using their immune systems. Mammalian hosts react to infections with an Innate immune system, innate response, often involving inflammation, followed by an Adaptive immune system, adaptive response. Treatment for infections depends on the type of pathogen involved. Common medications include: * Antibiotics for bacterial infections. * Antivirals for viral infections. * Antifungals for fungal infections. * Antiprotozoals for protozoan infections. * Antihelminthics for infections caused by parasi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sar RNA
Sar RNA is an antisense non-coding RNA that is partly responsible for the negative regulation of antirepressor synthesis during development of bacteriophage P22. The target of Sar RNA is ant mRNA. Structurally, Sar RNA forms two stem-loop Stem-loops are nucleic acid Biomolecular structure, secondary structural elements which form via intramolecular base pairing in single-stranded DNA or RNA. They are also referred to as hairpins or hairpin loops. A stem-loop occurs when two regi ...s. References External links * Antisense RNA {{molecular-cell-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monomer
A monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or two- or three-dimensional network in a process called polymerization. Classification Chemistry classifies monomers by type, and two broad classes based on the type of polymer they form. By type: * natural vs synthetic, e.g. glycine vs caprolactam, respectively * polar vs nonpolar, e.g. vinyl acetate vs ethylene, respectively * cyclic vs linear, e.g. ethylene oxide vs ethylene glycol, respectively By type of polymer they form: * those that participate in condensation polymerization * those that participate in addition polymerization Differing stoichiometry causes each class to create its respective form of polymer. : The polymerization of one kind of monomer gives a homopolymer. Many polymers are copolymers, meaning that they are derived from two different monomers. In the case of condensation polymerizations, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell (biology)
The cell is the basic structural and functional unit of all life, forms of life. Every cell consists of cytoplasm enclosed within a Cell membrane, membrane; many cells contain organelles, each with a specific function. The term comes from the Latin word meaning 'small room'. Most cells are only visible under a light microscope, microscope. Cells Abiogenesis, emerged on Earth about 4 billion years ago. All cells are capable of Self-replication, replication, protein synthesis, and cell motility, motility. Cells are broadly categorized into two types: eukaryotic cells, which possess a Cell nucleus, nucleus, and prokaryotic, prokaryotic cells, which lack a nucleus but have a nucleoid region. Prokaryotes are single-celled organisms such as bacteria, whereas eukaryotes can be either single-celled, such as amoebae, or multicellular organism, multicellular, such as some algae, plants, animals, and fungi. Eukaryotic cells contain organelles including Mitochondrion, mitochondria, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proteins
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phage
A bacteriophage (), also known informally as a phage (), is a virus that infects and replicates within bacteria. The term is derived . 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 biomass after prokaryotes, where up to 9x108 virions per millilitre have been found in microbial mats at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genes
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and non-coding genes. During gene expression (the synthesis of Gene product, RNA or protein from a gene), DNA is first transcription (biology), copied into RNA. RNA can be non-coding RNA, directly functional or be the intermediate protein biosynthesis, template for the synthesis of a protein. The transmission of genes to an organism's offspring, is the basis of the inheritance of phenotypic traits from one generation to the next. These genes make up different DNA sequences, together called a genotype, that is specific to every given individual, within the gene pool of the population (biology), population of a given species. The genotype, along with environmental and developmental factors, ultimately determines the phenotype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lysogenic
Lysogeny, or the lysogenic cycle, is one of two cycles of viral reproduction (the lytic cycle being the other). Lysogeny is characterized by integration of the bacteriophage nucleic acid into the host bacterium's genome or formation of a circular replicon in the bacterial cytoplasm. In this condition the bacterium continues to live and reproduce normally, while the bacteriophage lies in a dormant state in the host cell. The genetic material of the bacteriophage, called a prophage, can be transmitted to daughter cells at each subsequent cell division, and later events (such as UV radiation or the presence of certain chemicals) can release it, causing proliferation of new phages via the lytic cycle. Lysogenic cycles can also occur in eukaryotes, although the method of DNA incorporation is not fully understood. For instance, the HIV viruses can either infect humans lytically, or lay dormant (lysogenic) as part of the infected cells' genome, keeping the ability to return to l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lytic
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 can only go through 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 integrated into the host genome. This is the key difference between the lytic and lysogenic cycles. However, in both cases the virus/phage replicates using the host DNA machinery. Description The lytic cycle is often separated into six stages: attachment, penetration, transcription, biosynthesis, maturation, and lysis. # Attachment – the phage attaches itself to the surface of the host cell in order to inject its DNA i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmonella Typhimurium
''Salmonella enterica'' subsp. ''enterica'' is a subspecies of ''Salmonella enterica'', the rod-shaped, flagellated, aerobic, Gram-negative bacterium. Many of the pathogenic serovars of the ''S. enterica'' species are in this subspecies, including that responsible for typhoid. Serovars ''Salmonella enterica'' subsp. ''enterica'' serovars are defined based on their somatic (O) and flagellar (H) antigens, with over 2,600 serovars in total; only about 50 of these serovars are common causes of infections in humans. Most of these serovars are found in the environment and survive in plants, water, and soil; many serovars have broad host ranges that allow them to colonize different species in mammals, birds, reptiles, amphibians, and insects. Zoonotic diseases, like ''Salmonella'', spread between the environment and people. A number of techniques are currently used to differentiate between serotypes. These include looking for the presence or absence of antigens, phage typing, molecul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Helix
A beta helix is a tandem protein repeat structure formed by the association of parallel beta sheet in a helical pattern with either two or three faces. The beta helix is a type of solenoid protein domain. The structure is stabilized by inter-strand hydrogen bonds, protein-protein interactions, and sometimes bound metal ions. Both left- and right-handed beta helices have been identified. These structures are distinct from jelly-roll folds, a different protein structure sometimes known as a "double-stranded beta helix". The first beta-helix was observed in the enzyme pectate lyase, which contains a seven-turn helix that reaches 34 Å (3.4 nm) long. The P22 phage tail spike protein, a component of the P22 bacteriophage, has 13 turns and in its assembled homo trimer is 200 Å (20 nm) in length. Its interior is close-packed with no central pore and contains both hydrophobic residues and charged residues neutralized by salt bridges. Both pectate lyase and P22 tailspike prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
