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Multilocus Sequence Typing
Multilocus sequence typing (MLST) is a technique in molecular biology for the typing of multiple loci, using DNA sequences of internal fragments of multiple housekeeping genes to characterize isolates of microbial species. The first MLST scheme to be developed was for ''Neisseria meningitidis'', the causative agent of meningococcal meningitis and septicaemia. Since its introduction for the research of evolutionary history, MLST has been used not only for human pathogens but also for plant pathogens. Principle MLST directly measures the DNA sequence variations in a set of housekeeping genes and characterizes strains by their unique allelic profiles. The principle of MLST is simple: the technique involves PCR amplification followed by DNA sequencing. Nucleotide differences between strains can be checked at a variable number of genes depending on the degree of discrimination desired. The workflow of MLST involves: 1) data collection, 2) data analysis and 3) multilocus sequence ana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physical structure of biological macromolecules is known as molecular biology. Molecular biology was first described as an approach focused on the underpinnings of biological phenomena - uncovering the structures of biological molecules as well as their interactions, and how these interactions explain observations of classical biology. In 1945 the term molecular biology was used by physicist William Astbury. In 1953 Francis Crick, James Watson, Rosalind Franklin, and colleagues, working at Medical Research Council unit, Cavendish laboratory, Cambridge (now the MRC Laboratory of Molecular Biology), made a double helix model of DNA which changed the entire research scenario. They proposed the DNA structure based on previous research done by Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibrio Vulnificus
''Vibrio vulnificus'' is a species of Gram-negative, motile, curved rod-shaped (bacillus), pathogenic bacteria of the genus ''Vibrio''. Present in marine environments such as estuaries, brackish ponds, or coastal areas, ''V. vulnificus'' is related to '' ''V. cholerae'''', the causative agent of cholera. At least one strain of ''V. vulnificus'' is bioluminescent. Infection with ''V. vulnificus'' leads to rapidly expanding cellulitis or sepsis. It was first isolated as a source of disease in 1976. Signs and symptoms ''Vibrio vulnificus'' is an extremely virulent bacterium that can cause three types of infections: * Acute gastroenteritis from eating raw or undercooked shellfish: ''V. vulnificus'' causes an infection often incurred after eating seafood, especially raw or undercooked oysters. It does not alter the appearance, taste, or odor of oysters. Symptoms include vomiting, diarrhea, and abdominal pain. * Necrotizing wound infections can occur in injured skin exposed to contam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PFGE
Pulsed field gel electrophoresis is a technique used for the separation of large DNA molecules by applying to a gel matrix an electric field that periodically changes direction. Historical background Standard gel electrophoresis techniques for separation of DNA molecules provided huge advantages for molecular biology research. However, it was unable to separate very large molecules of DNA effectively. DNA molecules larger than 15–20 kb migrating through a gel will essentially move together in a size-independent manner. At Columbia University in 1984, David C. Schwartz and Charles Cantor developed a variation on the standard protocol by introducing an alternating voltage gradient to improve the resolution of larger molecules. This technique became known as pulsed-field gel electrophoresis (PFGE). The development of PFGE expanded the range of resolution for DNA fragments by as much as two orders of magnitude. Procedure The procedure for this technique is relatively similar to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimum Spanning Tree
A minimum spanning tree (MST) or minimum weight spanning tree is a subset of the edges of a connected, edge-weighted undirected graph that connects all the vertices together, without any cycles and with the minimum possible total edge weight. That is, it is a spanning tree whose sum of edge weights is as small as possible. More generally, any edge-weighted undirected graph (not necessarily connected) has a minimum spanning forest, which is a union of the minimum spanning trees for its connected components. There are many use cases for minimum spanning trees. One example is a telecommunications company trying to lay cable in a new neighborhood. If it is constrained to bury the cable only along certain paths (e.g. roads), then there would be a graph containing the points (e.g. houses) connected by those paths. Some of the paths might be more expensive, because they are longer, or require the cable to be buried deeper; these paths would be represented by edges with larger weights ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendrogram
A dendrogram is a diagram representing a tree. This diagrammatic representation is frequently used in different contexts: * in hierarchical clustering, it illustrates the arrangement of the clusters produced by the corresponding analyses. * in computational biology, it shows the clustering of genes or samples, sometimes in the margins of heatmaps. * in phylogenetics, it displays the evolutionary relationships among various biological taxa. In this case, the dendrogram is also called a phylogenetic tree. The name ''dendrogram'' derives from the two ancient greek words (), meaning "tree", and (), meaning "drawing, mathematical figure". Clustering example For a clustering example, suppose that five taxa (a to e) have been clustered by UPGMA based on a matrix of genetic distances. The hierarchical clustering dendrogram would show a column of five nodes representing the initial data (here individual taxa), and the remaining nodes represent the clusters to which the dat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isolation (microbiology)
In microbiology, the term isolation refers to the separation of a strain from a natural, mixed population of living microbes, as present in the environment, for example in water or soil, or from living beings with skin flora, oral flora or gut flora, in order to identify the microbe(s) of interest. Historically, the laboratory techniques of isolation first developed in the field of bacteriology and parasitology (during the 19th century), before those in virology during the 20th century. History The laboratory techniques of isolating microbes first developed during the 19th century in the field of bacteriology and parasitology using light microscopy. Proper isolation techniques of virology did not exist prior to the 20th century. The methods of microbial isolation have drastically changed over the past 50 years, from a labor perspective with increasing mechanization, and in regard to the technologies involved, and with it speed and accuracy. General techniques In order to iso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tryptophanase
The enzyme tryptophanase () catalyzes the chemical reaction :L-tryptophan + H2O \rightleftharpoons indole + pyruvate + NH3 This enzyme belongs to the family of lyases, specifically in the "catch-all" class of carbon-carbon lyases. The systematic name of this enzyme class is L-tryptophan indole-lyase (deaminating; pyruvate-forming). Other names in common use include L-tryptophanase, and L-tryptophan indole-lyase (deaminating). This enzyme participates in tryptophan metabolism and nitrogen metabolism. It has 2 cofactors: pyridoxal phosphate, and potassium. Structural studies As of late 2007, 3 structures A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ... have been solved for this class of enzymes, with PDB accession codes 1AX4, 2C44, and 2OQX. Retrieved from Protein Data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydroorotase
Dihydroorotase (, ''carbamoylaspartic dehydrase'', ''dihydroorotate hydrolase'') is an enzyme which converts carbamoyl aspartic acid into 4,5-dihydroorotic acid in the biosynthesis of pyrimidines. It forms a multifunctional enzyme with carbamoyl phosphate synthetase and aspartate transcarbamoylase. Dihydroorotase is a zinc metalloenzyme. See also * Pyrimidine biosynthesis Pyrimidine (; ) is an aromatic, heterocyclic, organic compound similar to pyridine (). One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has nitrogen atoms at positions 1 and 3 in the ring. The other ... References External links * * EC 3.5.2 {{transferase-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diaminopimelate Decarboxylase
The enzyme diaminopimelate decarboxylase () catalyzes the cleavage of carbon-carbon bonds in meso 2,6 diaminoheptanedioate to produce CO2 and L-lysine, the essential amino acid. It employs the cofactor pyridoxal phosphate, also known as PLP, which participates in numerous enzymatic transamination, decarboxylation and deamination reactions. This enzyme belongs to the family of lyases, specifically the carboxy-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is ''meso''-2,6-diaminoheptanedioate carboxy-lyase (L-lysine-forming).DAP-decarboxylase catalyzes the final step in the meso-diaminopimelate/lysine biosynthetic pathway. Lysine is used for protein synthesis and used in the peptidoglycan layer of Gram-positive bacteria cell walls. This enzyme is not found in humans, but the ortholog is ornithine decarboxylase. Structure DAPDC is a PLP-dependent enzyme belonging to the alanine racemase family. This enzyme is generally dimeric with each mono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Threonine Dehydrogenase
In enzymology, a L-threonine 3-dehydrogenase () is an enzyme that catalyzes the chemical reaction :L-threonine + NAD+ \rightleftharpoons L-2-amino-3-oxobutanoate + NADH + H+ Thus, the two substrates of this enzyme are L-threonine and NAD+, whereas its 3 products are L-2-amino-3-oxobutanoate, NADH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is L-threonine:NAD+ oxidoreductase. Other names in common use include L-threonine dehydrogenase, threonine 3-dehydrogenase, and threonine dehydrogenase. This enzyme participates in glycine, serine and threonine metabolism. Structural studies As of late 2007, 3 structures A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphoribosylaminoimidazole Synthetase
Phosphoribosylglycinamide formyltransferase (, ''2-amino-N-ribosylacetamide 5'-phosphate transformylase'', ''GAR formyltransferase'', ''GAR transformylase'', ''glycinamide ribonucleotide transformylase'', ''GAR TFase'', ''5,10-methenyltetrahydrofolate:2-amino-N-ribosylacetamide ribonucleotide transformylase'') is an enzyme with systematic name ''10-formyltetrahydrofolate:5'-phosphoribosylglycinamide N-formyltransferase''. This enzyme catalyses the following chemical reaction : 10-formyltetrahydrofolate + N1-(5-phospho-D-ribosyl)glycinamide \rightleftharpoons tetrahydrofolate + N2-formyl-N1-(5-phospho-D-ribosyl)glycinamide This THF dependent enzyme catalyzes a nucleophilic acyl substitution of the formyl group from 10-formyltetrahydrofolate (fTHF) to N1-(5-phospho-D-ribosyl)glycinamide (GAR) to form N2-formyl-N1-(5-phospho-D-ribosyl)glycinamide (fGAR) as shown above. This reaction plays an important role in the formation of purine through the ''de novo'' purine biosynthesis pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
