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Rhopalosiphum Padi Virus
Rhopalosiphum padi virus (RhPV) is a member of '' Dicistroviridae'' family, which includes cricket paralysis virus (CrPV), ''Plautia stali'' intestine virus and ''Drosophila'' C virus. Its 5'UTR region contains an internal ribosome entry site An internal ribosome entry site, abbreviated IRES, is an RNA element that allows for translation initiation in a cap-independent manner, as part of the greater process of protein synthesis. In eukaryotic translation, initiation typically occurs at ... (IRES) element with a cross-kingdom activity. It can function efficiently in mammalian, plant and insect translation systems. Testing of R. padi aphids collected from different sites in Sweden revealed the presence of RhPV in wild aphid populations for the first time in Europe. Virus could be detected in several life stages of R. padi, including sexual individuals and eggs, establishing an over-wintering route for the virus. References Cis-regulatory RNA elements Dicistroviridae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Structure
Protein secondary structure is the three dimensional form of ''local segments'' of proteins. The two most common secondary structural elements are alpha helices and beta sheets, though beta turns and omega loops occur as well. Secondary structure elements typically spontaneously form as an intermediate before the protein folds into its three dimensional tertiary structure. Secondary structure is formally defined by the pattern of hydrogen bonds between the amino hydrogen and carboxyl oxygen atoms in the peptide backbone. Secondary structure may alternatively be defined based on the regular pattern of backbone dihedral angles in a particular region of the Ramachandran plot regardless of whether it has the correct hydrogen bonds. The concept of secondary structure was first introduced by Kaj Ulrik Linderstrøm-Lang at Stanford in 1952. Other types of biopolymers such as nucleic acids also possess characteristic secondary structures. Types The most common secondary st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Conservation
In evolutionary biology, conserved sequences are identical or similar Sequence (biology), sequences in nucleic acids (DNA sequence, DNA and RNA) or peptide sequence, proteins across species (homology (biology)#Orthology, orthologous sequences), or within a genome (homology (biology)#Paralogy, paralogous sequences), or between donor and receptor taxa (Sequence homology#Xenology, xenologous sequences). Conservation indicates that a sequence has been maintained by natural selection. A highly conserved sequence is one that has remained relatively unchanged far back up the phylogenetic tree, and hence far back in geological time. Examples of highly conserved sequences include the Ribosomal RNA, RNA components of ribosomes present in all domain (biology), domains of life, the homeobox sequences widespread amongst Eukaryotes, and the tmRNA in Bacteria. The study of sequence conservation overlaps with the fields of genomics, proteomics, evolutionary biology, phylogenetics, bioinformatics ... [...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 re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicistroviridae
''Dicistroviridae'' is a family of viruses in the order ''Picornavirales''. Invertebrates, including aphids, leafhoppers, flies, bees, ants, and silkworms, serve as natural hosts. There are 15 species in this family, assigned to three genera. Diseases associated with this family include: DCV: increased reproductive potential. extremely pathogenic when injected with high associated mortality. CrPV: paralysis and death. Taxonomy Although many dicistroviruses were initially placed in the ''Picornaviridae'', they have since been reclassified into their own family. The name (Dicistro) is derived from the characteristic dicistronic arrangement of the genome. This family is a member of the Order ''Picornavirales'' (along with the families '' Iflaviridae'', ''Picornaviridae'', and ''Secoviridae'' and ''Marnaviridae''). Within this order, the gene order is the gene order of the nonstructural proteins Hel(helicase)-Pro(protease)-RdRp(polymerase). The ''Dicistroviridae'' can be distingui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cricket Paralysis Virus
Cricket paralysis virus (CrPV) was initially discovered in Australian field crickets ('' Teleogryllus commodus'' and '' Teleogryllus oceanicus'') by Carl Reinganum and his colleagues at the Victorian Plant Research Institute (Burnley, Melbourne, Australia). The paralytic disease spread rapidly through a breeding colony as well as through a laboratory population causing about 95% mortality. This was the first recorded isolate of the virus and is generally referred to as CrPVvic to distinguish it from subsequent isolates. Description The spheroidal, non-enveloped virus particles of CrPV are about 27 nm diameter in negatively-stained electron micrographs and contain a single piece of positive-sense ssRNA. The virion is composed of four capsid proteins with molecular masses generally reported to be 33, 31 and 30 kilodaltons with a minor VP4 protein of about 8 kDa. The particles resemble those of the mammalian picornaviruses but CrPV virions sediment at a faster rate (167 S) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila C Virus
''Drosophila'' C virus belongs to the genus ''Cripavirus'' and was previously thought to be a member of the virus family ''Picornaviridae''; it has since been classified as belonging to the ''Dicistroviridae''. It is a single stranded positive sense RNA virus of approximately 9300 nucleotides and it contains two open reading frames. The virus particles are 30 nm in diameter and are made up of approximately 30% of RNA and 70% protein. The virus capsid is composed of three major polypeptides and two minor polypeptides. ''Drosophila'' C virus was first discovered in the early 1970s in a French strain of ''Drosophila melanogaster'', but can also infect other ''Drosophila'' species in laboratory settings. The virus is transmitted by feeding and affects survival. However, experimental evidence has shown that when injected into adult flies the virus is pathogenic as it causes the adult flies to die within 3–4 days. Antiviral RNAi has been shown to be an important host defence again ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Five Prime Untranslated Region
The 5′ untranslated region (also known as 5′ UTR, leader sequence, transcript leader, or leader RNA) is the region of a messenger RNA (mRNA) that is directly upstream from the initiation codon. This region is important for the regulation of translation of a transcript by differing mechanisms in viruses, prokaryotes and eukaryotes. While called untranslated, the 5′ UTR or a portion of it is sometimes translated into a protein product. This product can then regulate the translation of the main coding sequence of the mRNA. In many organisms, however, the 5′ UTR is completely untranslated, instead forming a complex secondary structure to regulate translation. The 5′ UTR has been found to interact with proteins relating to metabolism, and within the 5′ UTR. In addition, this region has been involved in transcription regulation, such as the sex-lethal gene in ''Drosophila''. Regulatory elements within 5′ UTRs have also been linked to mRNA export. General structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Ribosome Entry Site
An internal ribosome entry site, abbreviated IRES, is an RNA element that allows for translation initiation in a cap-independent manner, as part of the greater process of protein synthesis. In eukaryotic translation, initiation typically occurs at the 5' end of mRNA molecules, since 5' cap recognition is required for the assembly of the initiation complex. The location for IRES elements is often in the 5'UTR, but can also occur elsewhere in mRNAs. History IRES sequences were first discovered in 1988 in the poliovirus (PV) and encephalomyocarditis virus (EMCV) RNA genomes in the labs of Nahum Sonenberg and Eckard Wimmer, respectively. They are described as distinct regions of RNA molecules that are able to recruit the eukaryotic ribosome to the mRNA. This process is also known as cap-independent translation. It has been shown that IRES elements have a distinct secondary or even tertiary structure, but similar structural features at the levels of either primary or secondary str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cis-regulatory RNA Elements
''Cis-acting replication elements'' bring together the 5′ and 3′ ends during replication of positive-sense single-stranded RNA viruses (for example Picornavirus, Flavivirus, coronavirus, togaviruses, Hepatitis C virus) and double-stranded RNA viruses (for example rotavirus and reovirus). See also *Cis-regulatory element * List of cis-regulatory RNA elements * Enterovirus cis-acting replication element and Enterovirus 5′ cloverleaf cis-acting replication element *Cardiovirus cis-acting replication element (CRE) * Coronavirus SL-III cis-acting replication element (CRE) * Rotavirus cis-acting replication element * Hepatitis C virus cis-acting replication element * Flavivirus 3′ UTR cis-acting replication element (CRE) *Potato virus X cis-acting regulatory element The Potato virus X cis-acting regulatory element is a cis-acting regulatory element found in the 3' UTR of the Potato virus X genome. This element has been found to be required for minus strand RNA accumulation an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
