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Parvoviridae
Parvoviruses are a family of animal viruses that constitute the family ''Parvoviridae''. They have linear, single-stranded DNA (ssDNA) genomes that typically contain two genes encoding for a replication initiator protein, called NS1, and the protein the viral capsid is made of. The coding portion of the genome is flanked by telomeres at each end that form into hairpin loops that are important during replication. Parvovirus virions are small compared to most viruses, at 23–28 nanometers in diameter, and contain the genome enclosed in an icosahedral capsid that has a rugged surface. Parvoviruses enter a host cell by endocytosis, travelling to the nucleus where they wait until the cell enters its replication stage. At that point, the genome is uncoated and the coding portion is replicated. Viral messenger RNA (mRNA) is then transcribed and translated, resulting in NS1 initiating replication. During replication, the hairpins repeatedly unfold, are replicated, and refold to chang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porcine Parvovirus
Porcine parvovirus (PPV), a virus in the species ''Ungulate protoparvovirus 1'' of genus ''Protoparvovirus'' in the virus family ''Parvoviridae'', causes reproductive failure of swine characterized by embryonic and fetal infection and death, usually in the absence of outward maternal clinical signs. The disease develops mainly when seronegative dams are exposed oronasally to the virus anytime during about the first half of gestation, and conceptuses are subsequently infected transplacentally before they become immunocompetent. There is no definitive evidence that infection of swine other than during gestation is of any clinical or economic significance. The virus is ubiquitous among swine throughout the world and is enzootic in most herds that have been tested. Diagnostic surveys have indicated that PPV is the major infectious cause of embryonic and fetal death. In addition to its direct causal role in reproductive failure, PPV can potentiate the effects of porcine circovirus t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolling Hairpin Replication
Rolling hairpin replication (RHR) is a unidirectional, strand displacement form of DNA replication used by parvoviruses, a group of viruses that constitute the family ''Parvoviridae''. Parvoviruses have linear, single-stranded DNA (ssDNA) genomes in which the coding portion of the genome is flanked by telomeres at each end that form hairpin loops. During RHR, these hairpin loops repeatedly unfold and refold to change the direction of DNA replication so that replication progresses in a continuous manner back and forth across the genome. RHR is initiated and terminated by an endonuclease encoded by parvoviruses that is variously called NS1 or Rep, and RHR is similar to rolling circle replication, which is used by ssDNA viruses that have circular genomes. Before RHR begins, a host cell DNA polymerase converts the genome to a duplex form in which the coding portion is double-stranded and connected to the terminal hairpins. From there, messenger RNA (mRNA) that encodes the viral initiato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canine Parvovirus
Canine parvovirus (also referred to as CPV, CPV2, or parvo) is a contagious virus mainly affecting dogs. CPV is highly contagious and is spread from dog to dog by direct or indirect contact with their feces. Vaccines can prevent this infection, but mortality can reach 91% in untreated cases. Treatment often involves veterinary hospitalization. Canine parvovirus often infects other mammals including foxes, wolves, cats, and skunks. Felines (cats) are also susceptible to panleukopenia, a different strain of parvovirus. Signs Dogs that develop the disease show signs of the illness within three to ten days. The signs may include lethargy, vomiting, fever, and diarrhea (usually bloody). Generally, the first sign of CPV is lethargy. Secondary signs are loss of weight and appetite or diarrhea followed by vomiting. Diarrhea and vomiting result in dehydration that upsets the electrolyte balance and this may affect the dog critically. Secondary infections occur as a result of the weaken ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parvovirus B19
Primate erythroparvovirus 1, generally referred to as B19 virus (B19V), parvovirus B19 or sometimes erythrovirus B19, is the first (and until 2005 the only) known human virus in the family ''Parvoviridae'', genus ''Erythroparvovirus''; it measures only 23–26 nm in diameter. The name is derived from Latin, parvum meaning small, reflecting the fact that B19 ranks among the smallest DNA viruses. B19 virus is most known for causing disease in the pediatric population; however, it can also affect adults. It is the classic cause of the childhood rash called fifth disease or erythema infectiosum, or "slapped cheek syndrome". The virus was discovered by chance in 1975 by Australian virologist Yvonne Cossart. It gained the B19 name because it was discovered in well B19 of a large series of microtiter plates. Virology Erythroviruses belong to the ''Parvoviridae'' family of small DNA viruses. Human parvovirus B19 is a non-enveloped, icosahedral virus that contains a single-stranded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minute Virus Of Mice
Minute virus of mice (MVM) is the exemplar virus of the species ''Rodent protoparvovirus 1'', in the genus ''Protoparvovirus'' of the ''Parvoviridae'' family of viruses. MVM exists in multiple variant forms including MVMp, which is the prototype strain that infects cells of fibroblast origin, while MVMi, the immunosuppressive strain, infects T lymphocytes. MVM is a common infection in laboratory mice due to its highly contagious nature. The virus can be shed from infected mice via feces and urine, but also via fomites and nasal secretions. Typically there are no clinical signs of infection in adult mice, however, experimental infection can cause multiple organ damage during fetal development or shortly after birth. Transcription profile MVM uses two transcriptional promoters at map units (mu) 4 and 38 (p4 and p38) and a single polyadenylation site at mu 95 to create 3 major size classes of mRNAs, referred to as R1, R2 and R3, all of which have a short intron sequence between 46 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adeno-associated Virus
Adeno-associated viruses (AAV) are small viruses that infect humans and some other primate species. They belong to the genus ''Dependoparvovirus'', which in turn belongs to the family ''Parvoviridae''. They are small (approximately 26 nm in diameter) replication-defective, nonenveloped viruses and have linear single-stranded DNA (ssDNA) genome of approximately 4.8 kilobases (kb). AAV are not currently known to cause disease. The viruses cause a very mild immune response. Several additional features make AAV an attractive candidate for creating viral vectors for gene therapy, and for the creation of isogenic human disease models. Gene therapy vectors using AAV can infect both dividing and quiescent cells and persist in an extrachromosomal state without integrating into the genome of the host cell. In the native virus, however, integration of virally carried genes into the host genome does occur. Integration can be important for certain applications, but can also have unwan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feline Parvovirus
''Carnivore protoparvovirus 1'' (CPPV 1) is a species of parvovirus that infects carnivorans. It causes a highly contagious disease in both dogs and cats separately. The disease is generally divided into two major genogroups: CPV-1 containing the classical feline panleukopenia virus (FPLV), and CPV-2 containing the canine parvovirus (CPV) which appeared in the 1970s. FPLV is known to infect all wild and domestic members of the felid (cat) family worldwide. It is a highly contagious, severe infection that causes gastrointestinal, immune system, and nervous system disease. Its primary effect is to decrease the number of white blood cells, causing the disease known as feline panleukopenia. Although it was once thought that only CPV-1 or FPLV infects cats, it has been confirmed that a feline panleukopenia illness can be caused by CPV 2a, 2b, and 2c. This being said, the virus cannot be transmitted across differing species. FPLV is commonly referred to as: * feline infectious ent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endonuclease
Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain. Some, such as deoxyribonuclease I, cut DNA relatively nonspecifically (without regard to sequence), while many, typically called restriction endonucleases or restriction enzymes, cleave only at very specific nucleotide sequences. Endonucleases differ from exonucleases, which cleave the ends of recognition sequences instead of the middle (endo) portion. Some enzymes known as "exo-endonucleases", however, are not limited to either nuclease function, displaying qualities that are both endo- and exo-like. Evidence suggests that endonuclease activity experiences a lag compared to exonuclease activity. Restriction enzymes are endonucleases from eubacteria and archaea that recognize a specific DNA sequence. The nucleotide sequence recognized for cleavage by a restriction enzyme is called the restriction site. Typically, a restriction site will be a palindromic sequence about four to six nucleotides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HUH-tag
HUH endonucleases (HUH-tags) are sequence-specific single-stranded DNA (ssDNA) binding proteins originating from numerous species of bacteria and viruses. Viral HUH endonucleases are involved in initiating rolling circle replication while ones of bacterial origin initiate bacterial conjugation. In biotechnology, they can be used to create protein-DNA linkages, akin to other methods such as SNAP-tag. In doing so, they create a 5' covalent bond between the ssDNA and the protein. HUH endonucleases can be fused with other proteins or used as protein tags. Types of HUH endonucleases HUH endonucleases are broadly split into two categories of enzymes: replication initiator proteins (Rep) or relaxase / mobilization proteins. They both contain small protein domains that recognize sequence-specific origins of replication or origin of transfer at which site they nick DNA. The nicking domain of Reps tend to be smaller, on the order of 10-20 kDa while nicking domains from relaxases are lar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the Roman Republic it became the dominant language in the Italian region and subsequently throughout the Roman Empire. Even after the fall of Western Rome, Latin remained the common language of international communication, science, scholarship and academia in Europe until well into the 18th century, when other regional vernaculars (including its own descendants, the Romance languages) supplanted it in common academic and political usage, and it eventually became a dead language in the modern linguistic definition. Latin is a highly inflected language, with three distinct genders (masculine, feminine, and neuter), six or seven noun cases (nominative, accusative, genitive, dative, ablative, and vocative), five declensions, four verb conjuga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Therapy
Gene therapy is a medical field which focuses on the genetic modification of cells to produce a therapeutic effect or the treatment of disease by repairing or reconstructing defective genetic material. The first attempt at modifying human DNA was performed in 1980, by Martin Cline, but the first successful nuclear gene transfer in humans, approved by the National Institutes of Health, was performed in May 1989. The first therapeutic use of gene transfer as well as the first direct insertion of human DNA into the nuclear genome was performed by French Anderson in a trial starting in September 1990. It is thought to be able to cure many genetic disorders or treat them over time. Between 1989 and December 2018, over 2,900 clinical trials were conducted, with more than half of them in phase I.Gene Therapy Cli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-terminus
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amine group is bonded to the carboxylic group of another amino acid, making it a chain. That leaves a free carboxylic group at one end of the peptide, called the C-terminus, and a free amine group on the other end called the N-terminus. By convention, peptide sequences are written N-terminus to C-terminus, left to right (in LTR writing systems). This correlates the translation direction to the text direction, because when a protein is translated from messenger RNA, it is created from the N-terminus to the C-terminus, as amino acids are added to the carboxyl end of the protein. Chemistry Each amino acid has an amine group and a carboxylic group. Amino acids link to one another by peptide bonds which form through a dehydration reaction that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
