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Avian Bornavirus
In 2008, by pyrosequencing of cDNA from the brains of several parrots suffering from proventricular dilatation disease (PDD), Honkavuori et al. identified the presence of a novel bornavirus. Discovery Using real time PCR, the investigators confirmed the presence of this virus in the brains and proventriculus of three cases of PDD but not in four unaffected birds. At approximately the same time, Kistler and her colleagues used a microarray approach to identify a bornavirus hybridization signature in three out of five PDD cases but not in eight control parrots. Recovery and naming Using high-throughput pyrosequencing in combination with conventional PCR cloning and sequencing, these investigators recovered the complete viral genome sequence and named this virus "avian bornavirus". Today, several distinct avian bornaviruses are distinguished. In general these viruses show only about 65% sequence identity with mammalian Borna disease virus 1 (BoDV-1). Taxonomy Structure The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proventricular Dilatation Disease
Proventricular dilatation disease (PDD) is an incurable probably viral disease of psittacine birds. It was first recognized and described in 1978 by Dr. Hannis L. Stoddard. Since the first reported cases were involving species of macaw, the condition was termed macaw wasting syndrome. Clinical signs The clinical presentation of this disease varies with the individual as well as in severity of those symptoms. Often the symptoms include a gastrointestinal component, but many times birds with this disease will present with neurologic signs as well, or in lieu of digestive anomalies. Gastrointestinal signs may include: Regurgitation, crop impaction, poor appetite, weight loss, or passage of undigested food in the feces.Harrison, and Lightfoot. 2006 ''Clinical Avian Medicine''. Spix Publishing, Palm Beach, Florida. Neurologic symptoms may include: Weakness, ataxia, paresis, proprioceptive deficits, head tremors, and rarely seizures. Muscle wasting and a generalized poor body condition is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bornavirus
''Bornaviridae'' is a family of negative-strand RNA viruses in the order ''Mononegavirales''. Horses, sheep, cattle, rodents, birds, reptiles, and humans serve as natural hosts. Diseases associated with bornaviruses include Borna disease, a fatal neurologic disease of mammals restricted to central Europe; and proventricular dilatation disease (PDD) in birds. Bornaviruses may cause encephalitis in mammals like horses or sheep. The family includes 11 species assigned to three genera. History Borna disease was first identified in 1926 and its genome was isolated in 1990. The ICTV proposed the creation in 1996 of the family ''Bornaviridae'' along with the genus ''Bornaviru''s (today ''Orthobornavirus''). The viral family is named after the city of Borna in Saxony, Germany, which is where many animals were lost to the sporadic encephalopathy caused by the viral disease. Structure Orthobornavirions are enveloped, with spherical geometries and helical capsids. The diameter is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerase Chain Reaction
The polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies (complete or partial) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) to a large enough amount to study in detail. PCR was invented in 1983 by the American biochemist Kary Mullis at Cetus Corporation; Mullis and biochemist Michael Smith, who had developed other essential ways of manipulating DNA, were jointly awarded the Nobel Prize in Chemistry in 1993. PCR is fundamental to many of the procedures used in genetic testing and research, including analysis of ancient samples of DNA and identification of infectious agents. Using PCR, copies of very small amounts of DNA sequences are exponentially amplified in a series of cycles of temperature changes. PCR is now a common and often indispensable technique used in medical laboratory research for a broad variety of applications including biomedical research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a wikt:submicroscopic, submicroscopic infectious agent that replicates only inside the living Cell (biology), 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'', consisti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proventriculus
The proventriculus is part of the digestive system of birds.Encarta World English Dictionary orth American Edition(2007). ''Proventriculus''. Source: (accessed: December 18, 2007) An analogous organ exists in invertebrates and insects. Birds The proventriculus is a standard part of avian anatomy, and is a rod shaped organ, located between the esophagus and the gizzard of most birds. It is generally a glandular part of the stomach that may store and/or commence digestion of food before it progresses to the gizzard. The primary function of the proventriculus is to secrete hydrochloric acid (HCl) and pepsinogen into the digestive compartments that will churn the ingested material through muscular mechanisms. The Encarta (2007) holds that the proventriculus is: The first part of a bird's stomach, where digestive enzymes are mixed with food before it goes to the gizzard. It is analogous to the gizzard in insects and crustaceans. Thomas Cecere (College of Veterinary Medicine of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microarray
A microarray is a multiplex lab-on-a-chip. Its purpose is to simultaneously detect the expression of thousands of genes from a sample (e.g. from a tissue). It is a two-dimensional array on a solid substrate—usually a glass slide or silicon thin-film cell—that assays (tests) large amounts of biological material using high-throughput screening miniaturized, multiplexed and parallel processing and detection methods. The concept and methodology of microarrays was first introduced and illustrated in antibody microarrays (also referred to as antibody matrix) by Tse Wen Chang in 1983 in a scientific publication and a series of patents. The " gene chip" industry started to grow significantly after the 1995 '' Science Magazine'' article by the Ron Davis and Pat Brown labs at Stanford University. With the establishment of companies, such as Affymetrix, Agilent, Applied Microarrays, Arrayjet, Illumina, and others, the technology of DNA microarrays has become the most sophis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloning
Cloning is the process of producing individual organisms with identical or virtually identical DNA, either by natural or artificial means. In nature, some organisms produce clones through asexual reproduction. In the field of biotechnology, cloning is the process of creating cloned organisms (copies) of cells and of DNA fragments (molecular cloning). Etymology Coined by Herbert J. Webber, the term clone derives from the Ancient Greek word (), ''twig'', which is the process whereby a new plant is created from a twig. In botany, the term ''lusus'' was used. In horticulture, the spelling ''clon'' was used until the early twentieth century; the final ''e'' came into use to indicate the vowel is a "long o" instead of a "short o". Since the term entered the popular lexicon in a more general context, the spelling ''clone'' has been used exclusively. Natural cloning Cloning is a natural form of reproduction that has allowed life forms to spread for hundreds of millions of years. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genome Sequence
In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as regulatory sequences (see non-coding DNA), and often a substantial fraction of 'junk' DNA with no evident function. Almost all eukaryotes have mitochondria and a small mitochondrial genome. Algae and plants also contain chloroplasts with a chloroplast genome. The study of the genome is called genomics. The genomes of many organisms have been sequenced and various regions have been annotated. The International Human Genome Project reported the sequence of the genome for ''Homo sapiens'' in 200The Human Genome Project although the initial "finished" sequence was missing 8% of the genome consisting mostly of repetitive sequences. With advancements in technology that could handle sequenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bornaviridae
''Bornaviridae'' is a family of negative-strand RNA viruses in the order ''Mononegavirales''. Horses, sheep, cattle, rodents, birds, reptiles, and humans serve as natural hosts. Diseases associated with bornaviruses include Borna disease, a fatal neurologic disease of mammals restricted to central Europe; and proventricular dilatation disease (PDD) in birds. Bornaviruses may cause encephalitis in mammals like horses or sheep. The family includes 11 species assigned to three genera. History Borna disease was first identified in 1926 and its genome was isolated in 1990. The ICTV proposed the creation in 1996 of the family ''Bornaviridae'' along with the genus ''Bornaviru''s (today ''Orthobornavirus''). The viral family is named after the city of Borna in Saxony, Germany, which is where many animals were lost to the sporadic encephalopathy caused by the viral disease. Structure Orthobornavirions are enveloped, with spherical geometries and helical capsids. The diameter is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Committee On Taxonomy Of Viruses
The International Committee on Taxonomy of Viruses (ICTV) authorizes and organizes the taxonomic classification of and the nomenclatures for viruses. The ICTV has developed a universal taxonomic scheme for viruses, and thus has the means to appropriately describe, name, and classify every virus that affects living organisms. The members of the International Committee on Taxonomy of Viruses are considered expert virologists. The ICTV was formed from and is governed by the Virology Division of the International Union of Microbiological Societies. Detailed work, such as delimiting the boundaries of species within a family, typically is performed by study groups of experts in the families. History The International Committee on Nomenclature of Viruses (ICNV) was established in 1966, at the International Congress for Microbiology in Moscow, to standardize the naming of viruses. The ICVN published its first report in 1971. For viruses infecting vertebrates, the first report includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bornavirus
''Bornaviridae'' is a family of negative-strand RNA viruses in the order ''Mononegavirales''. Horses, sheep, cattle, rodents, birds, reptiles, and humans serve as natural hosts. Diseases associated with bornaviruses include Borna disease, a fatal neurologic disease of mammals restricted to central Europe; and proventricular dilatation disease (PDD) in birds. Bornaviruses may cause encephalitis in mammals like horses or sheep. The family includes 11 species assigned to three genera. History Borna disease was first identified in 1926 and its genome was isolated in 1990. The ICTV proposed the creation in 1996 of the family ''Bornaviridae'' along with the genus ''Bornaviru''s (today ''Orthobornavirus''). The viral family is named after the city of Borna in Saxony, Germany, which is where many animals were lost to the sporadic encephalopathy caused by the viral disease. Structure Orthobornavirions are enveloped, with spherical geometries and helical capsids. The diameter is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription (genetics)
Transcription is the process of copying a segment of DNA into RNA. The segments of DNA transcribed into RNA molecules that can encode proteins are said to produce messenger RNA (mRNA). Other segments of DNA are copied into RNA molecules called non-coding RNAs (ncRNAs). mRNA comprises only 1–3% of total RNA samples. Less than 2% of the human genome can be transcribed into mRNA ( Human genome#Coding vs. noncoding DNA), while at least 80% of mammalian genomic DNA can be actively transcribed (in one or more types of cells), with the majority of this 80% considered to be ncRNA. Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a complementary language. During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, antiparallel RNA strand called a primary transcript. Transcription proceeds in the following general steps: # RNA polymerase, together with one or more general transcription factors, binds to promot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
