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RyeB RNA
The SdsR/RyeB RNA is a non-coding RNA that was identified in a large scale screen of ''E. coli''. The exact 5′ and 3′ ends of this RNA are uncertain. This RNA overlaps the SraC/RyeA RNA on the opposite strand suggesting that the two may act in a concerted manner. It is transcribed by general stress factor σs and is most highly expressed in stationary phase. SdsR/RyeB RNA interacts with Hfq. The homologous sRNA in ''S. enterica'' was shown to regulate synthesis of major porin OmpD. A study using ''Salmonella'' identified 20 targets of this sRNA including transcriptional regulator, CRP, global DNA-binding factors, StpA and HupB, the antibiotic transporter protein, TolC, and the RtsA/B two-component system (TCS), and validated their post-transcriptional control by SdsR/RyeB RNA. See also * RydB RNA *RyhB RNA *RyeE RNA The CyaR RNA (formerly known as RyeE RNA) non-coding RNA was identified in a large scale screen of ''Escherichia coli'' and was called candidate 14. The exac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Structure
Protein secondary structure is the three dimensional conformational isomerism, form of ''local segments'' of proteins. The two most common Protein structure#Secondary structure, secondary structural elements are alpha helix, 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 protein folding, folds into its three dimensional protein tertiary structure, tertiary structure. Secondary structure is formally defined by the pattern of hydrogen bonds between the Amine, amino hydrogen and carboxyl oxygen atoms in the peptide backbone chain, backbone. Secondary structure may alternatively be defined based on the regular pattern of backbone Dihedral angle#Dihedral angles of proteins, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Conservation
In evolutionary biology, conserved sequences are identical or similar sequences in nucleic acids ( DNA and RNA) or proteins across species ( orthologous sequences), or within a genome ( paralogous sequences), or between donor and receptor taxa ( 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 RNA components of ribosomes present in all 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 and mathematics. History The discovery of the role of DNA in heredity, and observations by Frederick Sanger of variation between animal insulins in 1949, promp ... [...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] |
Bacterial Small RNA
Bacterial small RNAs (bsRNA) are small RNAs produced by bacteria; they are 50- to 500-nucleotide non-coding RNA molecules, highly structured and containing several stem-loops. Numerous sRNAs have been identified using both computational analysis and laboratory-based techniques such as Northern blotting, microarrays and RNA-Seq in a number of bacterial species including ''Escherichia coli'', the model pathogen ''Salmonella'', the nitrogen-fixing Alphaproteobacteria, alphaproteobacterium ''Sinorhizobium meliloti'', marine cyanobacteria, ''Francisella tularensis'' (the causative agent of tularaemia), ''Streptococcus pyogenes','' the pathogen ''Staphylococcus aureus'''','' and the plant pathogen ''Xanthomonas oryzae pathovar oryzae''. Bacterial sRNAs affect how genes are expressed within bacterial cells via interaction with mRNA or protein, and thus can affect a variety of bacterial functions like metabolism, virulence, environmental stress response, and structure. Origin In the 1960s, t ... [...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] |
Non-coding RNA
A non-coding RNA (ncRNA) is a functional RNA molecule that is not translated into a protein. The DNA sequence from which a functional non-coding RNA is transcribed is often called an RNA gene. Abundant and functionally important types of non-coding RNAs include transfer RNAs (tRNAs) and ribosomal RNAs (rRNAs), as well as small RNAs such as microRNAs, siRNAs, piRNAs, snoRNAs, snRNAs, exRNAs, scaRNAs and the long ncRNAs such as Xist and HOTAIR. The number of non-coding RNAs within the human genome is unknown; however, recent transcriptomic and bioinformatic studies suggest that there are thousands of non-coding transcripts. Many of the newly identified ncRNAs have not been validated for their function. There is no consensus in the literature on how much of non-coding transcription is functional. Some researchers have argued that many ncRNAs are non-functional (sometimes referred to as "junk RNA"), spurious transcriptions. Others, however, disagree, arguing instead that many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SraC/RyeA RNA
The SraC/RyeA RNA is a non-coding RNA that was discovered in ''E. coli'' during two large scale screens for RNAs. The function of this RNA is currently unknown. This RNA overlaps the SdsR/RyeB RNA The SdsR/RyeB RNA is a non-coding RNA that was identified in a large scale screen of ''E. coli''. The exact 5′ and 3′ ends of this RNA are uncertain. This RNA overlaps the SraC/RyeA RNA on the opposite strand suggesting that the two may act i ... on the opposite strand suggesting that the two RNAs may act in a concerted manner. References External links * Non-coding RNA {{molecular-cell-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hfq Protein
The Hfq protein (also known as HF-I protein) encoded by the ''hfq'' gene was discovered in 1968 as an ''Escherichia coli'' host factor that was essential for replication of the bacteriophage Qβ. It is now clear that Hfq is an abundant bacterial RNA binding protein which has many important physiological roles that are usually mediated by interacting with Hfq binding sRNA. In ''E. coli'', Hfq mutants show multiple stress response related phenotypes. The Hfq protein is now known to regulate the translation of two major stress transcription factors ( σS (RpoS) and σE (RpoE) ) in Enterobacteria. It also regulates sRNA in ''Vibrio cholerae'', a specific example being MicX sRNA. In ''Salmonella typhimurium'', Hfq has been shown to be an essential virulence factor as its deletion attenuates the ability of ''S.typhimurium'' to invade epithelial cells, secrete virulence factors or survive in cultured macrophages. In ''Salmonella'', Hfq deletion mutants are also non motile and exhibit chro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmonella Enterica
''Salmonella enterica'' (formerly ''Salmonella choleraesuis'') is a rod-headed, flagellate, facultative anaerobic, Gram-negative bacterium and a species of the genus ''Salmonella''. A number of its serovars are serious human pathogens. Epidemiology Most cases of salmonellosis are caused by food infected with ''S. enterica'', which often infects cattle and poultry, though other animals such as domestic cats and hamsters have also been shown to be sources of infection in humans. Investigations of vacuum cleaner bags have shown that households can act as a reservoir of the bacterium; this is more likely if the household has contact with an infection source (i.e., members working with cattle or in a veterinary clinic). Raw chicken eggs and goose eggs can harbor ''S. enterica'', initially in the egg whites, although most eggs are not infected. As the egg ages at room temperature, the yolk membrane begins to break down and ''S. enterica'' can spread into the yolk. Refrigeration a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RydB RNA
The RydB RNA is a non-coding RNA originally identified in ''E. coli'' in an RNA screen. This gene is only 67 nucleotides in length and is composed of a hairpin like structure. RydB lies between the ''ydiC'' and ''ydiH'' in ''E. coli''. Homologous RNA genes have been found in other species such as ''Shigella flexneri'' and ''Salmonella'' species. The molecular function of this RNA is unknown. See also *RyhB RNA *RyeB RNA *RyeE RNA The CyaR RNA (formerly known as RyeE RNA) non-coding RNA was identified in a large scale screen of ''Escherichia coli'' and was called candidate 14. The exact 5′ and 3′ ends of this RNA are uncertain. This gene lies between yegQ and orgK in '' ... References External links * Non-coding RNA {{molecular-cell-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RyhB RNA
RyhB RNA is a 90 nucleotide RNA that down-regulates a set of iron-storage and iron-using proteins when iron is limiting; it is itself negatively regulated by the ferric uptake repressor protein, Fur ( Ferric uptake regulator). Discovery The gene was independently identified in two screens, named RyhB by Wassarman ''et al''. and called SraI by Argaman ''et al''. and was found to be expressed only in stationary phase. Function and regulation RyhB RNA levels are inversely correlated with mRNA levels for the ''sdhCDAB'' operon, encoding succinate dehydrogenase, as well as five other genes previously shown to be positively regulated by Fur by an unknown mechanism. These include two other genes encoding enzymes in the tricarboxylic acid cycle, ''acnA'' and ''fumA'', two ferritin genes, ''ftnA'' and ''bfr'', and a gene for superoxide dismutase, ''sodB''. A number of other genes have been predicted computationally and verified as targets by microarray analysis: ''napF'', ''sodA'', ''cysE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RyeE RNA
The CyaR RNA (formerly known as RyeE RNA) non-coding RNA was identified in a large scale screen of ''Escherichia coli'' and was called candidate 14. The exact 5′ and 3′ ends of this RNA are uncertain. This gene lies between yegQ and orgK in ''E. coli''. This small RNA was shown to be bound by the Hfq protein. This RNA has been renamed as CyaR for (cyclic AMP-activated RNA). It has been shown that the CyaR RNA acts as a repressor of the porin OmpX. It has also been shown that ''cyaR'' expression is tightly controlled by the cyclic AMP receptor protein, CRP. A comparative genomics approach was able to detect and verify the additional targets ''ptsI'', ''sdhA'' and ''yobF''. See also * RydB RNA *RyhB RNA RyhB RNA is a 90 nucleotide RNA that down-regulates a set of iron-storage and iron-using proteins when iron is limiting; it is itself negatively regulated by the ferric uptake repressor protein, Fur ( Ferric uptake regulator). Discovery The gene ... * RyeB RNA References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
