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Evolutionary Capacitance
Evolutionary capacitance is the storage and release of variation, just as electric capacitors store and release charge. Living systems are robust to mutations. This means that living systems accumulate genetic variation without the variation having a phenotypic effect. But when the system is disturbed (perhaps by stress), robustness breaks down, and the variation has phenotypic effects and is subject to the full force of natural selection. An evolutionary capacitor is a molecular switch mechanism that can "toggle" genetic variation between hidden and revealed states. If some subset of newly revealed variation is adaptive, it becomes fixed by genetic assimilation. After that, the rest of variation, most of which is presumably deleterious, can be switched off, leaving the population with a newly evolved advantageous trait, but no long-term handicap. For evolutionary capacitance to increase evolvability in this way, the switching rate should not be faster than the timescale of geneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutational Robustness
In evolutionary biology, robustness of a biological system (also called biological or genetic robustness) is the persistence of a certain characteristic or trait in a system under perturbations or conditions of uncertainty. Robustness in development is known as canalisation (genetics), canalization. According to the kind of perturbation involved, robustness can be classified as mutational, environment (biophysical), environmental, Genetic recombination, recombinational, or behavioral robustness ''etc''. Robustness is achieved through the combination of many genetics, genetic and molecular biology, molecular mechanisms and can Evolution, evolve by either direct or indirect natural selection, selection. Several model organism, model systems have been developed to experimentally study robustness and its evolutionary consequences. Classification Mutational robustness Mutational robustness (also called mutation tolerance) describes the extent to which an organism's phenotype remains ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Folding
Protein folding is the physical process by which a protein, after Protein biosynthesis, synthesis by a ribosome as a linear chain of Amino acid, amino acids, changes from an unstable random coil into a more ordered protein tertiary structure, three-dimensional structure. This structure permits the protein to become biologically functional or active. The folding of many proteins begins even during the translation of the polypeptide chain. The amino acids interact with each other to produce a well-defined three-dimensional structure, known as the protein's native state. This structure is determined by the amino-acid sequence or primary structure. The correct three-dimensional structure is essential to function, although some parts of functional proteins Intrinsically unstructured proteins, may remain unfolded, indicating that protein dynamics are important. Failure to fold into a native structure generally produces inactive proteins, but in some instances, misfolded proteins have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology (from Ancient Greek μορφή (morphḗ) "form", and λόγος (lógos) "word, study, research") is the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance (shape, structure, color, pattern, size), as well as the form and structure of internal parts like bones and organs, i.e., anatomy. This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of the overall structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Fried ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungal Prions
A fungal prion is a prion that infects hosts which are fungi. Fungal prions are naturally occurring proteins that can switch between multiple, structurally distinct conformations, at least one of which is self-propagating and transmissible to other prions. This transmission of protein state represents an epigenetic phenomenon where information is encoded in the protein structure itself, instead of in nucleic acids. Several prion-forming proteins have been identified in fungi, primarily in the yeast ''Saccharomyces cerevisiae''. These fungal prions are generally considered benign, and in some cases even confer a selectable advantage to the organism. Fungal prions have provided a model for the understanding of disease-forming mammalian prions. Study of fungal prions has led to a characterisation of the sequence features and mechanisms that enable prion domains to switch between functional and amyloid-forming states. Sequence features Prions are formed by portable, transmissible pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Translation (genetics)
In biology, translation is the process in living cells in which proteins are produced using RNA molecules as templates. The generated protein is a sequence of amino acids. This sequence is determined by the sequence of nucleotides in the RNA. The nucleotides are considered three at a time. Each such triple results in the addition of one specific amino acid to the protein being generated. The matching from nucleotide triple to amino acid is called the genetic code. The translation is performed by a large complex of functional RNA and proteins called ribosomes. The entire process is called gene expression. In translation, messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. The polypeptide later folds into an active protein and performs its functions in the cell. The polypeptide can also start folding during protein synthesis. The ribosome facilitates decoding by inducing the binding of complementary transfe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stop Codon
In molecular biology, a stop codon (or termination codon) is a codon (nucleotide triplet within messenger RNA) that signals the termination of the translation process of the current protein. Most codons in messenger RNA correspond to the addition of an amino acid to a growing polypeptide chain, which may ultimately become a protein; stop codons signal the termination of this process by binding release factors, which cause the ribosomal subunits to disassociate, releasing the amino acid chain. While start codons need nearby sequences or initiation factors to start translation, a stop codon alone is sufficient to initiate termination. Properties Standard codons In the standard genetic code, there are three different termination codons: Alternative stop codons There are variations on the standard genetic code, and alternative stop codons have been found in the mitochondrial genomes of vertebrates, '' Scenedesmus obliquus'', and '' Thraustochytrium''. Reassigned ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saccharomyces Cerevisiae
''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungal microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have been originally isolated from the skin of grapes. It is one of the most intensively studied eukaryotic model organisms in molecular and cell biology, much like '' Escherichia coli'' as the model bacterium. It is the microorganism which causes many common types of fermentation. ''S. cerevisiae'' cells are round to ovoid, 5–10 μm in diameter. It reproduces by budding. Many proteins important in human biology were first discovered by studying their homologs in yeast; these proteins include cell cycle proteins, signaling proteins, and protein-processing enzymes. ''S. cerevisiae'' is currently the only yeast cell known to have Berkeley bodies present, which are involved in particular secretory pathways. Antibodies again ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sup35p
Sup35p is the ''Saccharomyces cerevisiae'' (a yeast) eukaryotic translation release factor. More specifically, it is the yeast eukaryotic release factor 3 (eRF3), which forms the translation termination complex with eRF1 ( Sup45p in yeast). This complex recognizes and catalyzes the release of the nascent polypeptide chain when the ribosome encounters a stop codon. While eRF1 recognizes stop codons, eRF3 facilitates the release of the polypeptide chain through GTP hydrolysis. Partial loss of function results in nonsense suppression, in which stop codons are ignored and proteins are abnormally synthesized with carboxyl terminal extensions. Complete loss of function is fatal. History Sup35p was shown to propagate in a prion form in 1994 by Reed Wickner. For this reason it is an intensely studied protein. When yeast cells harbor Sup35p in the prion state the resulting phenotype is known as SI+ In SI+cells Sup35p exists in an amyloid state that can be propagated and passed to daug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escherichia Coli
''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Escherichia'' that is commonly found in the lower intestine of warm-blooded organisms. Most ''E. coli'' strains are part of the normal microbiota of the gut, where they constitute about 0.1%, along with other facultative anaerobes. These bacteria are mostly harmless or even beneficial to humans. For example, some strains of ''E. coli'' benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by harmful pathogenic bacteria. These mutually beneficial relationships between ''E. coli'' and humans are a type of mutualistic biological relationship—where both the humans and the ''E. coli'' are benefitting each other. ''E. coli'' is expelled into the environment within fecal matter. The bacterium grows massi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GroEL
GroEL is a protein which belongs to the chaperonin family of Chaperone (protein), molecular chaperones, and is found in many bacteria. It is required for the proper protein folding, folding of many proteins. To function properly, GroEL requires the lid-like cochaperonin protein complex GroES. In eukaryotes the Organelle, organellar proteins Hsp60 and Hsp10 are structurally and functionally nearly identical to GroEL and GroES, respectively, due to their endosymbiotic origin. HSP60 is implicated in mitochondrial protein import and macromolecular assembly. It may facilitate the correct folding of imported proteins, and may also prevent misfolding and promote the refolding and proper assembly of unfolded polypeptides generated under stress conditions in the mitochondrial matrix. HSP60 interacts with HRAS and with HBV protein X and HTLV-1 protein p40tax. HSP60 belongs to the chaperonin (HSP60) family. Note: This description may include information from UniProtKB. Alternate Names: 60 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transposon
A transposable element (TE), also transposon, or jumping gene, is a type of mobile genetic element, a nucleic acid sequence in DNA that can change its position within a genome. The discovery of mobile genetic elements earned Barbara McClintock a Nobel Prize in 1983. There are at least two classes of TEs: Class I TEs or retrotransposons generally function via reverse transcription, while Class II TEs or DNA transposons encode the protein transposase, which they require for insertion and excision, and some of these TEs also encode other proteins. Discovery by Barbara McClintock Barbara McClintock discovered the first TEs in maize (''Zea mays'') at the Cold Spring Harbor Laboratory in New York. McClintock was experimenting with maize plants that had broken chromosomes. In the winter of 1944–1945, McClintock planted corn kernels that were self-pollinated, meaning that the silk (style) of the flower received pollen from its own anther. These kernels came from a long lin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tribolium Castaneum
The red flour beetle (''Tribolium castaneum'') is a species of beetle in the family darkling beetle, Tenebrionidae, the darkling beetles. The red flour beetle, and other closely related beetles like ''Gnatocerus cornutus'', are a worldwide pest (organism), pest of stored products, particularly food grains, and a model organism for Ethology, ethological and food safety research. Description Adult beetles are small, around 3–4 mm long (1/8 inches), of a uniform rust, brown or black color. Head and pronotum are sometimes darker than rest of body. Ecology The red flour beetle attacks stored grain and other food products including flour, cereals, pasta, biscuits, beans, and nuts, causing loss and damage. The United Nations, in a recent post-harvest compendium, estimated that ''Tribolium castaneum'' and ''Tribolium confusum'', the confused flour beetle, are "the two most common secondary pests of all plant commodities in store throughout the world." A research on hermetic stor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
