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Microbial Pathogenesis
Microbial pathogenesis is a field of microbiology started at least as early as 1988, with the identification of the triune Falkow's criteria aka molecular Koch's postulates. In 1996 Fredricks and Relman proposed a seven-point list of "Molecular Guidelines for Establishing Microbial Disease Causation", because of "the discovery of nucleic acids" by Watson and Crick "as the source of genetic information and as the basis for precise characterization of an organism In biology, an organism () is any life, living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy (biology), taxonomy into groups such as Multicellular o ...." The subsequent development of the "ability to detect and manipulate these nucleic acid molecules in microorganisms has created a powerful means for identifying previously unknown microbial pathogens and for studying the host-parasite relationship." __TOC__ Postulates for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Microbiology
Microbiology () is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology, and parasitology. Eukaryotic microorganisms possess membrane-bound organelles and include fungi and protists, whereas prokaryotic organisms—all of which are microorganisms—are conventionally classified as lacking membrane-bound organelles and include Bacteria and Archaea. Microbiologists traditionally relied on culture, staining, and microscopy. However, less than 1% of the microorganisms present in common environments can be cultured in isolation using current means. Microbiologists often rely on molecular biology tools such as DNA sequence based identification, for example the 16S rRNA gene sequence used for bacteria identification. Viruses have been variably classified as organisms, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Falkow's Criteria
Molecular Koch's postulates are a set of experimental criteria that must be satisfied to show that a gene found in a pathogenic microorganism encodes a product that contributes to the disease caused by the pathogen. Genes that satisfy molecular Koch's postulates are often referred to as virulence factors. The postulates were formulated by the microbiologist Stanley Falkow in 1988 and are based on Koch's postulates. As per Falkow's original descriptions, the three postulates are: # "The phenotype or property under investigation should be associated with pathogenic members of a genus or pathogenic strains of a species. # Specific inactivation of the gene(s) associated with the suspected virulence trait should lead to a measurable loss in pathogenicity or virulence. # Reversion or allelic replacement of the mutated gene should lead to restoration of pathogenicity." To apply the molecular Koch's postulates to human diseases, researchers must identify which microbial genes are potential ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Nucleic Acids
Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). If the sugar is ribose, the polymer is RNA; if the sugar is the ribose derivative deoxyribose, the polymer is DNA. Nucleic acids are naturally occurring chemical compounds that serve as the primary information-carrying molecules in cells and make up the genetic material. Nucleic acids are found in abundance in all living things, where they create, encode, and then store information of every living cell of every life-form on Earth. In turn, they function to transmit and express that information inside and outside the cell nucleus to the interior operations of the cell and ultimately to the next generation of each living organism. The encoded information i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Watson And Crick
"Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid" was the first article published to describe the discovery of the double helix structure of DNA, using X-ray diffraction and the mathematics of a helix transform. It was published by Francis Crick and James D. Watson in the scientific journal ''Nature'' on pages 737–738 of its 171st volume (dated 25 April 1953). This article is often termed a "pearl" of science because it is brief and contains the answer to a fundamental mystery about living organisms. This mystery was the question of how it is possible that genetic instructions are held inside organisms and how they are passed from generation to generation. The article presents a simple and elegant solution, which surprised many biologists at the time who believed that DNA transmission was going to be more difficult to deduce and understand. The discovery had a major impact on biology, particularly in the field of genetics, enabling later resea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Genetic Information
A nucleic acid sequence is a succession of bases signified by a series of a set of five different letters that indicate the order of nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. By convention, sequences are usually presented from the 5' end to the 3' end. For DNA, the sense strand is used. Because nucleic acids are normally linear (unbranched) polymers, specifying the sequence is equivalent to defining the covalent structure of the entire molecule. For this reason, the nucleic acid sequence is also termed the primary structure. The sequence has capacity to represent information. Biological deoxyribonucleic acid represents the information which directs the functions of an organism. Nucleic acids also have a secondary structure and tertiary structure. Primary structure is sometimes mistakenly referred to as ''primary sequence''. Conversely, there is no parallel concept of secondary or tertiary sequence. Nucleotides Nucleic acids consi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Organism
In biology, an organism () is any life, living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy (biology), taxonomy into groups such as Multicellular organism, multicellular animals, plants, and fungi; or Unicellular organism, unicellular microorganisms such as protists, bacteria, and archaea. All types of organisms are capable of reproduction, Developmental biology, growth and development, homeostasis, maintenance, and some degree of response to Stimulus (physiology), stimuli. Beetles, squids, tetrapods, mushrooms, and vascular plants are examples of multicellular organisms that Cellular differentiation, differentiate specialized tissue (biology), tissues and organ (anatomy), organs during developmental biology, development. A unicellular organism may be either a prokaryote or a eukaryote. Prokaryotes are represented by two separate Three-domain system, domains – bacteria and arc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Relapse
In internal medicine, relapse or recidivism is a recurrence of a past (typically medical) condition. For example, multiple sclerosis and malaria often exhibit peaks of activity and sometimes very long periods of dormancy, followed by relapse or recrudescence. In psychiatry, relapse or reinstatement of drug-seeking behavior, is the recurrence of pathological drug use, self harm or other symptoms after a period of recovery. Relapse is often observed in individuals who have developed a drug addiction or a form of drug dependence, as well as those who have a mental disorder. Risk factors Dopamine D2 receptor availability The availability of the dopamine receptor D2 plays a role in self-administration and the reinforcing effects of cocaine and other stimulants. The D2 receptor availability has an inverse relationship to the vulnerability of reinforcing effects of the drug. With the D2 receptors becoming limited, the user becomes more susceptible to the reinforcing effects o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Microbiology
Microbiology () is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology, and parasitology. Eukaryotic microorganisms possess membrane-bound organelles and include fungi and protists, whereas prokaryotic organisms—all of which are microorganisms—are conventionally classified as lacking membrane-bound organelles and include Bacteria and Archaea. Microbiologists traditionally relied on culture, staining, and microscopy. However, less than 1% of the microorganisms present in common environments can be cultured in isolation using current means. Microbiologists often rely on molecular biology tools such as DNA sequence based identification, for example the 16S rRNA gene sequence used for bacteria identification. Viruses have been variably classified as organisms, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Diseases And Disorders
A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that are associated with specific signs and symptoms. A disease may be caused by external factors such as pathogens or by internal dysfunctions. For example, internal dysfunctions of the immune system can produce a variety of different diseases, including various forms of immunodeficiency, hypersensitivity, allergies and autoimmune disorders. In humans, ''disease'' is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, or death to the person affected, or similar problems for those in contact with the person. In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structure and f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Epidemiology
Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants of health and disease conditions in a defined population. It is a cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results (including peer review and occasional systematic review). Epidemiology has helped develop methodology used in clinical research, public health studies, and, to a lesser extent, basic research in the biological sciences. Major areas of epidemiological study include disease causation, transmission, outbreak investigation, disease surveillance, environmental epidemiology, forensic epidemiology, occupational epidemiology, screening, biomonitoring, and comparisons of treatment effects such as in clinical t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |