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DEFA6
Defensin, alpha 6 (DEFA6) also known as human alpha defensin 6 (HD6) is a human protein that is encoded by the ''DEFA6'' gene. ''DEFA6'' is expressed in the Paneth cells of the ileum. Function The alpha defensins are a family of microbicidal and cytotoxic peptides that defend the host against bacteria and viruses. HD6 has poor antibacterial potency. However, HD6 affords protection against invasion by enteric bacterial pathogens by self-assembly to form fibrils and nanonets that surround and entangle bacteria. Several alpha defensin Defensins are small cysteine-rich cationic proteins across cellular life, including vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, ... genes, including ''DEFA6'', are clustered on chromosome 8. References Further reading * * * * * * External links PDBe-KBprovides an overview of all the structure information av ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defensin
Defensins are small cysteine-rich cationic proteins across cellular life, including vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ... and invertebrate animals, plants, and fungi. They are host defense peptides, with members displaying either direct Antimicrobial peptides, antimicrobial activity, Immune system, immune signalling activities, or both. They are variously active against bacteria, fungus, fungi and many enveloped and nonenveloped viruses. They are typically 18-45 amino acids in length, with three or four highly conserved disulphide bonds. In animals, they are produced by cells of the innate immune system and epithelial cells, whereas in plants and fungi they are produced by a wide variety of tissues. An organism usually produces many different defensins, some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Defensins
Alpha defensins are a family of mammalian defensin peptides of the alpha subfamily. In mammals they are also known as cryptdins and are produced within the small bowel. ''Cryptdin'' is a portmanteau of ''crypt'' and ''defensin''. Defensins are 2-6 kDa, cationic, microbicidal peptides active against many Gram-negative and Gram-positive bacteria, fungi, and enveloped viruses, containing three pairs of intramolecular disulfide bonds. On the basis of their size and pattern of disulfide bonding, mammalian defensins are classified into alpha, beta and theta categories. Alpha-defensins, which have been identified in humans, monkeys and several rodent species, are particularly abundant in neutrophils, certain macrophage populations and Paneth cells of the small intestine. Defensins are produced constitutively and/or in response to microbial products or proinflammatory cytokines. Some defensins are also called corticostatins (CS) because they inhibit corticotropin-stimulated corticostero ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
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 residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and 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 noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paneth Cells
Paneth cells are cells in the small intestine epithelium, alongside goblet cells, enterocytes, and enteroendocrine cells. Some can also be found in the cecum and vermiform appendix, appendix. They are below the intestinal stem cells in the intestinal glands (also called crypts of Lieberkühn gland, Lieberkühn) and the large eosinophilic refractile granules that occupy most of their cytoplasm. These granules consist of several anti-microbial compounds and other compounds that are known to be important in immunity and host-defense. When exposed to bacteria or bacterial antigens, Paneth cells secrete some of these compounds into the lumen (anatomy), lumen of the intestinal gland, thereby contributing to maintenance of the gastrointestinal barrier. Paneth cells are named after 19th-century pathologist Joseph Paneth. Structure Paneth cells are found throughout the small intestine and the appendix at the base of the intestinal glands. The Paneth cell increase in numbers towards the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ileum
The ileum () is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum. Its main function is to absorb vitamin B12, bile salts, and whatever products of digestion that were not absorbed by the jejunum. The ileum follows the duodenum and jejunum and is separated from the cecum by the ileocecal valve (ICV). In humans, the ileum is about 2–4 m long, and the pH is usually between 7 and 8 (neutral or slightly basic). ''Ileum ''is derived from the Greek word ''eilein'', meaning "to twist up tightly". Structure The ileum is the third and final part of the small intestine. It follows the jejunum and ends at the ileocecal junction, where the terminal ileum communicates with the cecum of the large intestine through the ileocecal valve. The ileum, along with the jejunum, is suspended ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viruses
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic material, i.e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enteric
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines. Food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled at the anus as feces. ''Gastrointestinal'' is an adjective meaning of or pertaining to the stomach and intestines. Most animals have a "through-gut" or complete digestive tract. Exceptions are more primitive ones: sponges have small pores ( ostia) throughout their body for digestion and a larger dorsal pore (osculum) for excretion, comb jellies have both a ventral mouth and dorsal anal pores, while cnidarians and acoels have a single pore for both digestion and excretion. The human gastrointestinal tract consists of the esophagus, stomach, and intestines, and is div ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathogens
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ''pathogen'' came into use in the 1880s. Typically, the term ''pathogen'' is used to describe an ''infectious'' microorganism or agent, such as a virus, bacterium, protozoan, prion, viroid, or fungus. Small animals, such as helminths and insects, can also cause or transmit disease. However, these animals are usually referred to as parasites rather than pathogens. The scientific study of microscopic organisms, including microscopic pathogenic organisms, is called microbiology, while parasitology refers to the scientific study of parasites and the organisms that host them. There are several pathways through which pathogens can invade a host. The principal pathways have different episodic time frames, but soil has the longest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibrils
Fibrils (from the Latin ''fibra'') are structural biological materials found in nearly all living organisms. Not to be confused with fibers or filaments, fibrils tend to have diameters ranging from 10-100 nanometers (whereas fibers are micro to milli-scale structures and filaments have diameters approximately 10-50 nanometers in size). Fibrils are not usually found alone but rather are parts of greater hierarchical structures commonly found in biological systems. Due to the prevalence of fibrils in biological systems, their study is of great importance in the fields of microbiology, biomechanics, and materials science. Structure and mechanics Fibrils are composed of linear biopolymers, and are characterized by rod-like structures with high length-to-diameter ratios. They often spontaneously arrange into helical structures. In biomechanics problems, fibrils can be characterized as classical beams with a roughly circular cross-sectional area on the nanometer scale. As such, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanonets
A nanonet is a net with fibers on the scale of nanometers. The net can be composed of carbon, metals, silicon, or peptides, such as nanonets composed of the defensin HD6. The word ''nanonet'' is also used in reference to a nanoscale communication network,Nanoscale Communication Networks, Bush, S. F., , Artech House, 2010/ref> which also uses key components on the scale of a hundred nanometers as officially defined in IEEE P1906.1 The IEEE P1906.1 - Recommended Practice for Nanoscale and Molecular Communication Framework is a standards working group sponsored by the IEEE Communications Society Standards Development Board whose goal is to develop a common framework for nano .... See also * IEEE P1906.1 Recommended Practice for Nanoscale and Molecular Communication Framework References {{Reflist Nanomaterials ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
