115-573: Tropaeolum tuberosum ( mashua , see below for other names) is a species of flowering plant in the family Tropaeolaceae, grown in the Andes , particularly in Peru and Bolivia , and to a lesser extent in Ecuador as well as in some areas of Colombia , for its edible tubers , which are eaten cooked or roasted as a vegetable. It is a minor food source, especially for native Amerindian populations. Mashua
230-423: A mutation–selection balance . It is predicted that a viral quasispecies at a low but evolutionarily neutral and highly connected (that is, flat) region in the fitness landscape will outcompete a quasispecies located at a higher but narrower fitness peak in which the surrounding mutants are unfit, "the quasispecies effect" or the "survival of the flattest". There is no suggestion that a viral quasispecies resembles
345-405: A ring species . Also, among organisms that reproduce only asexually , the concept of a reproductive species breaks down, and each clone is potentially a microspecies. Although none of these are entirely satisfactory definitions, and while the concept of species may not be a perfect model of life, it is still a useful tool to scientists and conservationists for studying life on Earth, regardless of
460-400: A "classical" method of determining species, such as with Linnaeus, early in evolutionary theory. However, different phenotypes are not necessarily different species (e.g. a four-winged Drosophila born to a two-winged mother is not a different species). Species named in this manner are called morphospecies . In the 1970s, Robert R. Sokal , Theodore J. Crovello and Peter Sneath proposed
575-424: A 'smallest clade' idea" (a phylogenetic species concept). Mishler and Wilkins and others concur with this approach, even though this would raise difficulties in biological nomenclature. Wilkins cited the ichthyologist Charles Tate Regan 's early 20th century remark that "a species is whatever a suitably qualified biologist chooses to call a species". Wilkins noted that the philosopher Philip Kitcher called this
690-473: A 1% gel formulation has proven to increase the healing activities of open wounds in mice populations. Further studies are necessary to determine potential wound healing success for human application. Mashua is a food item known for its exceptional nutritional properties. The protein content of the dry weight was reported to be about 6.9-15.7%. It has a remarkable protein profile with a considerable abundance of essential amino acids in an ideal ratio, providing
805-571: A baby or when the body needs to recover from malnutrition or trauma or after an operation. According to US & Canadian Dietary Reference Intake guidelines, women ages 19–70 need to consume 46 grams of protein per day while men ages 19–70 need to consume 56 grams of protein per day to minimize risk of deficiencies. These Recommended Dietary Allowances (RDAs) were calculated based on 0.8 grams protein per kilogram body weight and average body weights of 57 kg (126 pounds) and 70 kg (154 pounds), respectively. However, this recommendation
920-413: A baseline protein diet in a meta-analysis. Benefits of decreased body mass index as well as HDL cholesterol were more strongly observed in studies with only a slight increase in protein intake rather where high protein intake was classified as 45% of total energy intake. Detrimental effects to cardiovascular activity were not observed in short-term diets of 6 months or less. There is little consensus on
1035-790: A concentration greater than 7%, are (in no particular order) buckwheat, oats, rye, millet, maize (corn), rice, wheat, sorghum, amaranth, and quinoa. Game meat is an affordable protein source in some countries. Plant sources of proteins include legumes , nuts , seeds, grains, and some vegetables and fruits . Plant foods with protein concentrations greater than 7% include (but are not limited to) soybeans , lentils, kidney beans, white beans, mung beans, chickpeas , cowpeas, lima beans, pigeon peas, lupines, wing beans, almonds , Brazil nuts , cashews , pecans, walnuts , cotton seeds, pumpkin seeds , hemp seeds , sesame seeds , and sunflower seeds . Photovoltaic-driven microbial protein production uses electricity from solar panels and carbon dioxide from
1150-428: A connected series of neighbouring populations, each of which can sexually interbreed with adjacent related populations, but for which there exist at least two "end" populations in the series, which are too distantly related to interbreed, though there is a potential gene flow between each "linked" population. Such non-breeding, though genetically connected, "end" populations may co-exist in the same region thus closing
1265-432: A different species from its ancestors. Viruses have enormous populations, are doubtfully living since they consist of little more than a string of DNA or RNA in a protein coat, and mutate rapidly. All of these factors make conventional species concepts largely inapplicable. A viral quasispecies is a group of genotypes related by similar mutations, competing within a highly mutagenic environment, and hence governed by
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#17327761962831380-508: A genetic boundary suitable for defining a species concept is present. DNA barcoding has been proposed as a way to distinguish species suitable even for non-specialists to use. One of the barcodes is a region of mitochondrial DNA within the gene for cytochrome c oxidase . A database, Barcode of Life Data System , contains DNA barcode sequences from over 190,000 species. However, scientists such as Rob DeSalle have expressed concern that classical taxonomy and DNA barcoding, which they consider
1495-428: A high biological value. The essential amino acids leucine , isoleucine , and valine are branched-chain amino acids (BCAA), which are essential in muscle metabolism. The amount of free amino acids ranges from 2.763 to 6.826 mg/g dry matter. Variations occur depending on the region of cultivation and the specific mashua genotype. The fat content of the dry weight of mashua is between 0.1–0.4%. The investigation of
1610-622: A long period (2–5 hours per training session) use protein as a source of 5–10% of their total energy expended. Therefore, a slight increase in protein intake may be beneficial to endurance athletes by replacing the protein lost in energy expenditure and protein lost in repairing muscles. One review concluded that endurance athletes may increase daily protein intake to a maximum of 1.2–1.4 g per kg body weight. Research also indicates that individuals performing strength training activity require more protein than sedentary individuals. Strength-training athletes may increase their daily protein intake to
1725-400: A low protein diet (0.6 g/kg/d - 0.8 g/kg/d) may develop metabolic compensations that preserve kidney function, although in some people, malnutrition may occur. Individuals with phenylketonuria (PKU) must keep their intake of phenylalanine – an essential amino acid – extremely low to prevent a mental disability and other metabolic complications. Phenylalanine
1840-446: A maximum of 1.4–1.8 g per kg body weight to enhance muscle protein synthesis, or to make up for the loss of amino acid oxidation during exercise. Many athletes maintain a high-protein diet as part of their training. In fact, some athletes who specialize in anaerobic sports (e.g., weightlifting) believe a very high level of protein intake is necessary, and so consume high protein meals and also protein supplements. A food allergy
1955-492: A misnomer, need to be reconciled, as they delimit species differently. Genetic introgression mediated by endosymbionts and other vectors can further make barcodes ineffective in the identification of species. A phylogenetic or cladistic species is "the smallest aggregation of populations (sexual) or lineages (asexual) diagnosable by a unique combination of character states in comparable individuals (semaphoronts)". The empirical basis – observed character states – provides
2070-501: A nutritional standpoint is its amino acid composition. There are multiple systems which rate proteins by their usefulness to an organism based on their relative percentage of amino acids and, in some systems, the digestibility of the protein source. They include biological value , net protein utilization , and PDCAAS (Protein Digestibility Corrected Amino Acids Score) which was developed by
2185-449: A particular species, including which genus (and higher taxa) it is placed in, is a hypothesis about the evolutionary relationships and distinguishability of that group of organisms. As further information comes to hand, the hypothesis may be corroborated or refuted. Sometimes, especially in the past when communication was more difficult, taxonomists working in isolation have given two distinct names to individual organisms later identified as
2300-534: A person's diet is determined in large part by overall energy intake, the body's need for nitrogen and essential amino acids, body weight and composition, rate of growth in the individual, physical activity level, the individual's energy and carbohydrate intake, and the presence of illness or injury. Physical activity and exertion as well as enhanced muscular mass increase the need for protein. Requirements are also greater during childhood for growth and development, during pregnancy, or when breastfeeding in order to nourish
2415-780: A proposed maximum daily protein intake would be approximately 25% of energy requirements i.e. approximately 2 to 2.5 g/kg. However, many questions still remain to be resolved. In addition, some have suggested that athletes using restricted-calorie diets for weight loss should further increase their protein consumption, possibly to 1.8–2.0 g/kg, in order to avoid loss of lean muscle mass. Endurance athletes differ from strength-building athletes in that endurance athletes do not build as much muscle mass from training as strength-building athletes do. Research suggests that individuals performing endurance activity require more protein intake than sedentary individuals so that muscles broken down during endurance workouts can be repaired. Although
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#17327761962832530-402: A recommended limit for the intake of red and processed meat. While the report acknowledges research showing that lower intake of red and processed meat is correlated with reduced risk of cardiovascular diseases in adults, it also notes the value of nutrients provided from these meats. The recommendation is not to limit intake of meats or protein, but rather to monitor and keep within daily limits
2645-400: A short way of saying that something applies to many species within a genus, but not to all. If scientists mean that something applies to all species within a genus, they use the genus name without the specific name or epithet. The names of genera and species are usually printed in italics . However, abbreviations such as "sp." should not be italicised. When a species' identity is not clear,
2760-404: A specialist may use "cf." before the epithet to indicate that confirmation is required. The abbreviations "nr." (near) or "aff." (affine) may be used when the identity is unclear but when the species appears to be similar to the species mentioned after. With the rise of online databases, codes have been devised to provide identifiers for species that are already defined, including: The naming of
2875-523: A species as groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups. It has been argued that this definition is a natural consequence of the effect of sexual reproduction on the dynamics of natural selection. Mayr's use of the adjective "potentially" has been a point of debate; some interpretations exclude unusual or artificial matings that occur only in captivity, or that involve animals capable of mating but that do not normally do so in
2990-400: A species as determined by a taxonomist. A typological species is a group of organisms in which individuals conform to certain fixed properties (a type), so that even pre-literate people often recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens (such as longer or shorter tails) would differentiate the species. This method was used as
3105-491: A species. All species definitions assume that an organism acquires its genes from one or two parents very like the "daughter" organism, but that is not what happens in HGT. There is strong evidence of HGT between very dissimilar groups of prokaryotes , and at least occasionally between dissimilar groups of eukaryotes , including some crustaceans and echinoderms . The evolutionary biologist James Mallet concludes that there
3220-685: A species. Generally the term includes the unknown element of a distinct act of creation. Many authors have argued that a simple textbook definition, following Mayr's concept, works well for most multi-celled organisms , but breaks down in several situations: Species identification is made difficult by discordance between molecular and morphological investigations; these can be categorised as two types: (i) one morphology, multiple lineages (e.g. morphological convergence , cryptic species ) and (ii) one lineage, multiple morphologies (e.g. phenotypic plasticity , multiple life-cycle stages). In addition, horizontal gene transfer (HGT) makes it difficult to define
3335-528: A taxonomic decision at the discretion of cognizant specialists, is not governed by the Codes of Zoological or Botanical Nomenclature, in contrast to the PhyloCode , and contrary to what is done in several other fields, in which the definitions of technical terms, like geochronological units and geopolitical entities, are explicitly delimited. The nomenclatural codes that guide the naming of species, including
3450-517: A traditional biological species. The International Committee on Taxonomy of Viruses has since 1962 developed a universal taxonomic scheme for viruses; this has stabilised viral taxonomy. Most modern textbooks make use of Ernst Mayr 's 1942 definition, known as the Biological Species Concept as a basis for further discussion on the definition of species. It is also called a reproductive or isolation concept. This defines
3565-503: A type of infrared spectroscopy is used. The Food and Agriculture Organization of the United Nations (FAO) recommends that only amino acid analysis be used to determine protein in, inter alia , foods used as the sole source of nourishment, such as infant formula, but also provides: "When data on amino acids analyses are not available, determination of protein based on total N content by Kjeldahl (AOAC, 2000) or similar method ...
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3680-447: A variation on the morphological species concept, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms. It differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species
3795-515: A variety of reasons. Viruses are a special case, driven by a balance of mutation and selection , and can be treated as quasispecies . Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics . Early taxonomists such as Linnaeus had no option but to describe what they saw: this was later formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts,
3910-494: A viable, effective, and eco-friendly alternative to synthetic pesticides. Traits like these raise the potential for mashua to be used in agroecology . Raw mashua tuber is bitter due to glucosinolates , but the bitterness diminishes after cooking, freezing, or pounding. The tubers comprise as much as 75 percent of the mature plants by dry weight. Popularization of mashua may be limited by its intense flavor and reputation as an anaphrodisiac . Father Bernabé Cobo records that in
4025-438: Is "an entity composed of organisms which maintains its identity from other such entities through time and over space, and which has its own independent evolutionary fate and historical tendencies". This differs from the biological species concept in embodying persistence over time. Wiley and Mayden stated that they see the evolutionary species concept as "identical" to Willi Hennig 's species-as-lineages concept, and asserted that
4140-476: Is a herbaceous perennial climber growing to 2–4 m (7–13 ft) in height. It is related to garden nasturtiums , and is occasionally cultivated as an ornamental for its brightly coloured tubular flowers. This plant is commonly called mashua in Peru and Ecuador, but other names include: In Boyacá, Colombia, it is also named nabu The plant thrives even in marginal soils and competes well with weeds. It
4255-415: Is a component of the artificial sweetener aspartame, so people with PKU need to avoid low calorie beverages and foods with this ingredient. The U.S. and Canadian Dietary Reference Intake review for protein concluded that there was not sufficient evidence to establish a Tolerable upper intake level , i.e., an upper limit for how much protein can be safely consumed. When amino acids are in excess of needs,
4370-400: Is a group of sexually reproducing organisms that recognise one another as potential mates. Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms; no matter whether populations can hybridise successfully, they are still distinct cohesion species if
4485-460: Is a measure of all sources of nitrogen and includes nonprotein nitrogen, such as urea, which has no food value to humans. ... Current milk-testing equipment measures peptide bonds, a direct measure of true protein." Measuring peptide bonds in grains has also been put into practice in several countries including Canada, the UK, Australia, Russia and Argentina where near-infrared reflectance (NIR) technology,
4600-586: Is a nutrient needed by the human body for growth and maintenance. Aside from water, proteins are the most abundant kind of molecules in the body. Protein can be found in all cells of the body and is the major structural component of all cells in the body, especially muscle . This also includes body organs, hair and skin. Proteins are also used in membranes, such as glycoproteins . When broken down into amino acids, they are used as precursors to nucleic acid , co-enzymes, hormones, immune response, cellular repair, and other molecules essential for life. Additionally, protein
4715-458: Is a set of organisms adapted to a particular set of resources, called a niche, in the environment. According to this concept, populations form the discrete phenetic clusters that we recognise as species because the ecological and evolutionary processes controlling how resources are divided up tend to produce those clusters. A genetic species as defined by Robert Baker and Robert Bradley is a set of genetically isolated interbreeding populations. This
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4830-545: Is an abnormal immune response to proteins in food. The signs and symptoms may range from mild to severe. They may include itchiness , swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure. These symptoms typically occurs within minutes to one hour after exposure. When the symptoms are severe, it is known as anaphylaxis . The following eight foods are responsible for about 90% of allergic reactions: cow's milk , eggs , wheat , shellfish , fish , peanuts , tree nuts and soy . While there
4945-638: Is based on structural requirements but disregards use of protein for energy metabolism . This requirement is for a normal sedentary person. In the United States, average protein consumption is higher than the RDA. According to results of the National Health and Nutrition Examination Survey (NHANES 2013–2014), average protein consumption for women ages 20 and older was 69.8 grams and for men 98.3 grams/day. According to research from Harvard University,
5060-414: Is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses ) are given a two-part name , called a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature , also sometimes in zoological nomenclature ). For example, Boa constrictor
5175-414: Is called speciation . Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book The Origin of Species . Speciation depends on a measure of reproductive isolation , a reduced gene flow. This occurs most easily in allopatric speciation, where populations are separated geographically and can diverge gradually as mutations accumulate. Reproductive isolation
5290-417: Is considered acceptable." The testing method for protein in beef cattle feed has grown into a science over the post-war years. The standard text in the United States, Nutrient Requirements of Beef Cattle , has been through eight editions over at least seventy years. The 1996 sixth edition substituted for the fifth edition's crude protein the concept of " metabolizeable protein ", which was defined around
5405-403: Is described formally, in a publication that assigns it a unique scientific name. The description typically provides means for identifying the new species, which may not be based solely on morphology (see cryptic species ), differentiating it from other previously described and related or confusable species and provides a validly published name (in botany) or an available name (in zoology) when
5520-671: Is further weakened by the existence of microspecies , groups of organisms, including many plants, with very little genetic variability, usually forming species aggregates . For example, the dandelion Taraxacum officinale and the blackberry Rubus fruticosus are aggregates with many microspecies—perhaps 400 in the case of the blackberry and over 200 in the dandelion, complicated by hybridisation , apomixis and polyploidy , making gene flow between populations difficult to determine, and their taxonomy debatable. Species complexes occur in insects such as Heliconius butterflies, vertebrates such as Hypsiboas treefrogs, and fungi such as
5635-726: Is hard or even impossible to test. Later biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, and the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: (1) agamospecies for asexual organisms (2) biospecies for reproductively isolated sexual organisms (3) ecospecies based on ecological niches (4) evolutionary species based on lineage (5) genetic species based on gene pool (6) morphospecies based on form or phenotype and (7) taxonomic species,
5750-626: Is needed to form blood cells. Protein occurs in a wide range of food. On a worldwide basis, plant protein foods contribute over 60% of the per capita supply of protein. In North America, animal-derived foods contribute about 70% of protein sources. Insects are a source of protein in many parts of the world. In parts of Africa, up to 50% of dietary protein derives from insects. It is estimated that more than 2 billion people eat insects daily. Meat , dairy, eggs, soybeans , fish , whole grains , and cereals are sources of protein. Examples of food staples and cereal sources of protein, each with
5865-403: Is no conclusive evidence that a high protein diet can cause chronic kidney disease , there is a consensus that people with this disease should decrease consumption of protein. According to one 2009 review updated in 2018, people with chronic kidney disease who reduce protein consumption have less likelihood of progressing to end stage kidney disease. Moreover, people with this disease while using
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#17327761962835980-403: Is no easy way to tell whether related geographic or temporal forms belong to the same or different species. Species gaps can be verified only locally and at a point of time. One is forced to admit that Darwin's insight is correct: any local reality or integrity of species is greatly reduced over large geographic ranges and time periods. The botanist Brent Mishler argued that the species concept
6095-653: Is not synthesized in adults. There are five amino acids which humans are able to synthesize in the body. These five are alanine , aspartic acid , asparagine , glutamic acid and serine . There are six conditionally essential amino acids whose synthesis can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress. These six are arginine , cysteine , glycine , glutamine , proline and tyrosine . Dietary sources of protein include grains , legumes , nuts , seeds , meats , dairy products, fish , eggs , edible insects , and seaweeds . Protein
6210-478: Is not valid, notably because gene flux decreases gradually rather than in discrete steps, which hampers objective delimitation of species. Indeed, complex and unstable patterns of gene flux have been observed in cichlid teleosts of the East African Great Lakes . Wilkins argued that "if we were being true to evolution and the consequent phylogenetic approach to taxa, we should replace it with
6325-400: Is one of the species of the genus Boa , with constrictor being the species' epithet. While the definitions given above may seem adequate at first glance, when looked at more closely they represent problematic species concepts. For example, the boundaries between closely related species become unclear with hybridisation , in a species complex of hundreds of similar microspecies , and in
6440-414: Is planted as a companion crop to repel pests in potato fields. Mashua’s high natural resistance to pests has made it a good crop for its potential in pest management. Glucosinolates contained in the plant have been shown to harm aphid herbivory. Spraying a crop with a mixture containing glucosinolates sourced from Masha can lead to up to 97% of aphid mortality. Molecules extracted from Mashua can be part of
6555-586: Is similar to Mayr's Biological Species Concept, but stresses genetic rather than reproductive isolation. In the 21st century, a genetic species could be established by comparing DNA sequences. Earlier, other methods were available, such as comparing karyotypes (sets of chromosomes ) and allozymes ( enzyme variants). An evolutionarily significant unit (ESU) or "wildlife species" is a population of organisms considered distinct for purposes of conservation. In palaeontology , with only comparative anatomy (morphology) and histology from fossils as evidence,
6670-422: Is sometimes an important source of genetic variation. Viruses can transfer genes between species. Bacteria can exchange plasmids with bacteria of other species, including some apparently distantly related ones in different phylogenetic domains , making analysis of their relationships difficult, and weakening the concept of a bacterial species. Protein (nutrient) Proteins are essential nutrients for
6785-429: Is supposed to have beneficial health effects and help relieve functional constipation, a common gastrointestinal problem in children. Mashua contains substantial levels of vitamin C , as well as β-carotene , which can be converted into vitamin A . The levels of vitamin C in mashua are influenced by both the geographical area where it is grown and its genetic profile. A study conducted by Coloma et al. in 2022 found that
6900-434: Is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity . Other ways of defining species include their karyotype , DNA sequence, morphology , behaviour, or ecological niche . In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes
7015-529: Is therefore used by many food standards agencies around the world, though the Dumas method is also approved by some standards organizations. Accidental contamination and intentional adulteration of protein meals with non-protein nitrogen sources that inflate crude protein content measurements have been known to occur in the food industry for decades. To ensure food quality , purchasers of protein meals routinely conduct quality control tests designed to detect
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#17327761962837130-594: Is threatened by hybridisation, but this can be selected against once a pair of populations have incompatible alleles of the same gene, as described in the Bateson–Dobzhansky–Muller model . A different mechanism, phyletic speciation, involves one lineage gradually changing over time into a new and distinct form (a chronospecies ), without increasing the number of resultant species. Horizontal gene transfer between organisms of different species, either through hybridisation , antigenic shift , or reassortment ,
7245-466: Is well-adapted to high-altitude subsistence agriculture and gives high yields; 30 tonnes per hectare are yielded at 3000 meters, but up to 70 tons per hectare have been produced under research conditions. Its extraordinary resistance to insects, nematode and bacterial pests is attributed to high levels of isothiocyanates . Although mashua is fully domesticated, it can persist in wild vegetation because of its aggressive growth and robustness. In Colombia, it
7360-530: The ICZN for animals and the ICN for plants, do not make rules for defining the boundaries of the species. Research can change the boundaries, also known as circumscription, based on new evidence. Species may then need to be distinguished by the boundary definitions used, and in such cases the names may be qualified with sensu stricto ("in the narrow sense") to denote usage in the exact meaning given by an author such as
7475-508: The Kjeldahl method and the Dumas method . These tests determine the total nitrogen in a sample. The only major component of most food which contains nitrogen is protein (fat, carbohydrate and dietary fiber do not contain nitrogen). If the amount of nitrogen is multiplied by a factor depending on the kinds of protein expected in the food the total protein can be determined. This value is known as
7590-409: The fatty acid composition of mashua flour by Ramallo (2004) showed a significant content of polyunsaturated fatty acids of 70.8%. The most abundant fatty acids are linoleic acid (48.7%), α-linolenic acid (22.13%), palmitic acid (21.2%) and oleic acid (3.96%). Ideally, the omega-6 to omega-3 fatty acid ratio should be between 1 and 4. For mashua the ratio between linoleic acid (omega-6) and
7705-399: The fly agaric . Natural hybridisation presents a challenge to the concept of a reproductively isolated species, as fertile hybrids permit gene flow between two populations. For example, the carrion crow Corvus corone and the hooded crow Corvus cornix appear and are classified as separate species, yet they can hybridise where their geographical ranges overlap. A ring species is
7820-540: The human body . They are one of the building blocks of body tissue and can also serve as a fuel source . As a fuel, proteins provide as much energy density as carbohydrates : 17 kJ (4 kcal ) per gram; in contrast, lipids provide 37 kJ (9 kcal) per gram. The most important aspect and defining characteristic of protein from a nutritional standpoint is its amino acid composition. Proteins are polymer chains made of amino acids linked together by peptide bonds . During human digestion , proteins are broken down in
7935-404: The intestinal absorptive cells is not the end. There, most of the peptides are broken into single amino acids. Absorption of the amino acids and their derivatives into which dietary protein is degraded is done by the gastrointestinal tract . The absorption rates of individual amino acids are highly dependent on the protein source; for example, the digestibilities of many amino acids in humans,
8050-507: The jaguar ( Panthera onca ) of Latin America or the leopard ( Panthera pardus ) of Africa and Asia. In contrast, the scientific names of species are chosen to be unique and universal (except for some inter-code homonyms ); they are in two parts used together : the genus as in Puma , and the specific epithet as in concolor . A species is given a taxonomic name when a type specimen
8165-620: The stomach to smaller polypeptide chains via hydrochloric acid and protease actions. This is crucial for the absorption of the essential amino acids that cannot be biosynthesized by the body. There are nine essential amino acids which humans must obtain from their diet in order to prevent protein-energy malnutrition and resulting death. They are phenylalanine , valine , threonine , tryptophan , methionine , leucine , isoleucine , lysine , and histidine . There has been debate as to whether there are 8 or 9 essential amino acids. The consensus seems to lean towards 9 since histidine
8280-483: The " crude protein " content. The use of correct conversion factors is heavily debated, specifically with the introduction of more plant-derived protein products. However, on food labels the protein is calculated by the nitrogen multiplied by 6.25, because the average nitrogen content of proteins is about 16%. The Kjeldahl test is typically used because it is the method the AOAC International has adopted and
8395-406: The "cynical species concept", and arguing that far from being cynical, it usefully leads to an empirical taxonomy for any given group, based on taxonomists' experience. Other biologists have gone further and argued that we should abandon species entirely, and refer to the "Least Inclusive Taxonomic Units" (LITUs), a view that would be coherent with current evolutionary theory. The species concept
8510-417: The "labile protein reserve" to compensate for daily variations in protein intake. However, unlike body fat as a reserve for future caloric needs, there is no protein storage for future needs. Excessive protein intake may increase calcium excretion in urine, occurring to compensate for the pH imbalance from oxidation of sulfur amino acids. This may lead to a higher risk of kidney stone formation from calcium in
8625-503: The 16th century, the Inca used to give enormous amounts of mashua to their troops so that they would forget their wives. However, mashua tubers roasted in traditional earthen field ovens, built at harvest, are considered a delicacy. Also, the raw tubers can be shredded thinly and added to salads to confer a spicy flavor and crunchy texture. In its native range, mashua is mainly cultivated for its edible tubers. Still, it has ornamental value in
8740-885: The FDA as a modification of the Protein efficiency ratio (PER) method. The PDCAAS rating was adopted by the US Food and Drug Administration (FDA) and the Food and Agricultural Organization of the United Nations/ World Health Organization (FAO/WHO) in 1993 as "the preferred 'best'" method to determine protein quality. These organizations have suggested that other methods for evaluating the quality of protein are inferior. In 2013 FAO proposed changing to Digestible Indispensable Amino Acid Score . Most proteins are decomposed to single amino acids by digestion in
8855-883: The National Academy of Medicine suggests that adults should consume at least 0.8 grams of protein per kilogram of body weight daily, which is roughly equivalent to a little more than 7 grams for every 20 pounds of body weight. This recommendation is widely accepted by health professionals as a guideline for maintaining muscle mass, supporting metabolic functions, and promoting overall health. Several studies have concluded that active people and athletes may require elevated protein intake (compared to 0.8 g/kg) due to increase in muscle mass and sweat losses, as well as need for body repair and energy source. Suggested amounts vary from 1.2 to 1.4 g/kg for those doing endurance exercise to as much as 1.6-1.8 g/kg for strength exercise and up to 2.0 g/kg/day for older people, while
8970-615: The Spanish chronicler Cobo that mashua was fed to their armies by the Inca Emperors , "that they should forget their wives". Studies of male rats fed on mashua tubers have shown a 45% drop in testosterone levels due to the presence of isothiocyanates . Mashua contains Docosatetraenoylethanolamide , a cannabinoid structurally similar to Anandamide that also acts on the cannabinoid (CB 1 ) receptor among other structurally related compounds such as N–oleoyldopamine. Topical mashua in
9085-405: The abbreviation "sp." in the singular or "spp." (standing for species pluralis , Latin for "multiple species") in the plural in place of the specific name or epithet (e.g. Canis sp.). This commonly occurs when authors are confident that some individuals belong to a particular genus but are not sure to which exact species they belong, as is common in paleontology . Authors may also use "spp." as
9200-539: The air to create fuel for microbes, which are grown in bioreactor vats and then processed into dry protein powders. The process makes highly efficient use of land, water and fertiliser. People eating a balanced diet do not need protein supplements . The table below presents food groups as protein sources. Colour key: Protein powders – such as casein , whey , egg , rice , soy and cricket flour – are processed and manufactured sources of protein. The classic assays for protein concentration in food are
9315-570: The amount of hybridisation is insufficient to completely mix their respective gene pools . A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology , genes can move freely even between distantly related bacteria, possibly extending to the whole bacterial domain. As a rule of thumb, microbiologists have assumed that members of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA–DNA hybridisation to decide if they belong to
9430-403: The belly and legs. This edema is explained by the action of lipoxygenase on arachidonic acid to form leukotrienes and the normal functioning of proteins in fluid balance and lipoprotein transport. PEM is fairly common worldwide in both children and adults and accounts for 6 million deaths annually. In the industrialized world, PEM is predominantly seen in hospitals, is associated with disease, or
9545-474: The biological species concept, "the several versions" of the phylogenetic species concept, and the idea that species are of the same kind as higher taxa are not suitable for biodiversity studies (with the intention of estimating the number of species accurately). They further suggested that the concept works for both asexual and sexually-reproducing species. A version of the concept is Kevin de Queiroz 's "General Lineage Concept of Species". An ecological species
9660-505: The biological species concept, a cladistic species does not rely on reproductive isolation – its criteria are independent of processes that are integral in other concepts. Therefore, it applies to asexual lineages. However, it does not always provide clear cut and intuitively satisfying boundaries between taxa, and may require multiple sources of evidence, such as more than one polymorphic locus, to give plausible results. An evolutionary species, suggested by George Gaylord Simpson in 1951,
9775-433: The concept of a chronospecies can be applied. During anagenesis (evolution, not necessarily involving branching), some palaeontologists seek to identify a sequence of species, each one derived from the phyletically extinct one before through continuous, slow and more or less uniform change. In such a time sequence, some palaeontologists assess how much change is required for a morphologically distinct form to be considered
9890-411: The difference between soy and milk proteins and between individual milk proteins, beta-lactoglobulin and casein. For milk proteins, about 50% of the ingested protein is absorbed between the stomach and the jejunum and 90% is absorbed by the time the digested food reaches the ileum . Biological value (BV) is a measure of the proportion of absorbed protein from a food which becomes incorporated into
10005-435: The evidence to support hypotheses about evolutionarily divergent lineages that have maintained their hereditary integrity through time and space. Molecular markers may be used to determine diagnostic genetic differences in the nuclear or mitochondrial DNA of various species. For example, in a study done on fungi , studying the nucleotide characters using cladistic species produced the most accurate results in recognising
10120-441: The gastro-intestinal tract. Digestion typically begins in the stomach when pepsinogen is converted to pepsin by the action of hydrochloric acid , and continued by trypsin and chymotrypsin in the small intestine. Before the absorption in the small intestine , most proteins are already reduced to single amino acid or peptides of several amino acids. Most peptides longer than four amino acids are not absorbed. Absorption into
10235-461: The impact of genetic variation on the nutritional makeup of mashua tubers. Regarding calcium content, mashua exhibits a lower concentration than potatoes, with the latter containing approximately 13,100 mg/100 g dry matter. In contrast, the phosphorus content of mashua is considerably higher than that of potatoes, which have a mere 0.23 mg/100 g dry matter. While potatoes present a significant amount of potassium at 500 mg/100 g dry matter, which surpasses
10350-474: The levels found in purple mashua tubers, they still hold merely a third of the potassium content when contrasted with yellow and yellow-purple mashua varieties. [REDACTED] Media related to Tropaeolum tuberosum at Wikimedia Commons Species A species ( pl. : species) is a population of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring , typically by sexual reproduction . It
10465-502: The levels of β-carotene in tubers also fluctuate according to the cultivation location and the plant's genotype. For yellow tubers, β-carotene content ranges from 18.10 to 715.95 μg/g dry matter. The concentration spans from 6.91 to 336.33 μg/g dry matter in tubers with a yellow-purple hue. Conversely, purple tubers exhibit a β-carotene content significantly lower, varying from 1.21 to 4.46 μg/g dry matter. An important aspect of mashua’s appeal lies in its rich mineral composition, which, as
10580-446: The liver takes up the amino acids and deaminates them, a process converting the nitrogen from the amino acids into ammonia , further processed in the liver into urea via the urea cycle . Excretion of urea occurs via the kidneys. Other parts of the amino acid molecules can be converted into glucose and used for fuel. When food protein intake is periodically high or low, the body tries to keep protein levels at an equilibrium by using
10695-428: The most common non-protein nitrogen contaminants, such as urea and ammonium nitrate . In at least one segment of the food industry, the dairy industry, some countries (at least the U.S., Australia, France and Hungary) have adopted " true protein " measurement, as opposed to crude protein measurement, as the standard for payment and testing: "True protein is a measure of only the proteins in milk, whereas crude protein
10810-483: The numerous fungi species of all the concepts studied. Versions of the phylogenetic species concept that emphasise monophyly or diagnosability may lead to splitting of existing species, for example in Bovidae , by recognising old subspecies as species, despite the fact that there are no reproductive barriers, and populations may intergrade morphologically. Others have called this approach taxonomic inflation , diluting
10925-410: The overall carbohydrate profile. Approximately 85% of the starch content is readily digestible, while 15% remains indigestible within the gastrointestinal tract. The tubers of the mashua are a good source of dietary fiber . Mashua tubers contain approximately 5 to 7 g of fiber per 100 g of dry matter, depending on factors like growing conditions and the variety of mashua species. Dietary fiber content
11040-593: The paper is accepted for publication. The type material is usually held in a permanent repository, often the research collection of a major museum or university, that allows independent verification and the means to compare specimens. Describers of new species are asked to choose names that, in the words of the International Code of Zoological Nomenclature , are "appropriate, compact, euphonious, memorable, and do not cause offence". Books and articles sometimes intentionally do not identify species fully, using
11155-674: The person who named the species, while the antonym sensu lato ("in the broad sense") denotes a wider usage, for instance including other subspecies. Other abbreviations such as "auct." ("author"), and qualifiers such as "non" ("not") may be used to further clarify the sense in which the specified authors delineated or described the species. Species are subject to change, whether by evolving into new species, exchanging genes with other species, merging with other species or by becoming extinct. The evolutionary process by which biological populations of sexually-reproducing organisms evolve to become distinct or reproductively isolated as species
11270-492: The potentially detrimental effects to healthy individuals of a long-term high protein diet, leading to caution advisories about using high protein intake as a form of weight loss . The 2015–2020 Dietary Guidelines for Americans (DGA) recommends that men and teenage boys increase their consumption of fruits, vegetables and other under-consumed foods, and that a means of accomplishing this would be to reduce overall intake of protein foods. The 2015 - 2020 DGA report does not set
11385-479: The protein requirement for athletes still remains controversial (for instance see Lamont, Nutrition Research Reviews, pages 142 - 149, 2012), research does show that endurance athletes can benefit from increasing protein intake because the type of exercise endurance athletes participate in still alters the protein metabolism pathway. The overall protein requirement increases because of amino acid oxidation in endurance-trained athletes. Endurance athletes who exercise over
11500-424: The proteins of the organism's body. Newborns of mammals are exceptional in protein digestion and assimilation in that they can absorb intact proteins at the small intestine. This enables passive immunity , i.e., transfer of immunoglobulins from the mother to the newborn, via milk. Considerable debate has taken place regarding issues surrounding protein intake requirements. The amount of protein required in
11615-419: The renal circulatory system. One meta-analysis reported no adverse effects of higher protein intakes on bone density. Another meta-analysis reported a small decrease in systolic and diastolic blood pressure with diets higher in protein, with no differences between animal and plant protein. High protein diets have been shown to lead to an additional 1.21 kg of weight loss over a period of 3 months versus
11730-487: The result of misclassification leading to questions on whether there really are any ring species. The commonly used names for kinds of organisms are often ambiguous: "cat" could mean the domestic cat, Felis catus , or the cat family, Felidae . Another problem with common names is that they often vary from place to place, so that puma, cougar, catamount, panther, painter and mountain lion all mean Puma concolor in various parts of America, while "panther" may also mean
11845-586: The ring. Ring species thus present a difficulty for any species concept that relies on reproductive isolation. However, ring species are at best rare. Proposed examples include the herring gull – lesser black-backed gull complex around the North pole, the Ensatina eschscholtzii group of 19 populations of salamanders in America, and the greenish warbler in Asia, but many so-called ring species have turned out to be
11960-508: The same species. This concept was narrowed in 2006 to a similarity of 98.7%. The average nucleotide identity (ANI) method quantifies genetic distance between entire genomes , using regions of about 10,000 base pairs . With enough data from genomes of one genus, algorithms can be used to categorize species, as for Pseudomonas avellanae in 2013, and for all sequenced bacteria and archaea since 2020. Observed ANI values among sequences appear to have an "ANI gap" at 85–95%, suggesting that
12075-529: The same species. When two species names are discovered to apply to the same species, the older species name is given priority and usually retained, and the newer name considered as a junior synonym, a process called synonymy . Dividing a taxon into multiple, often new, taxa is called splitting . Taxonomists are often referred to as "lumpers" or "splitters" by their colleagues, depending on their personal approach to recognising differences or commonalities between organisms. The circumscription of taxa, considered
12190-741: The sodium (< 2300 mg), saturated fats (less than 10% of total calories per day), and added sugars (less than 10% of total calories per day) that may be increased as a result of consumption of certain meats and proteins. While the 2015 DGA report does advise for a reduced level of consumption of red and processed meats, the 2015-2020 DGA key recommendations recommend that a variety of protein foods be consumed, including both vegetarian and non-vegetarian sources of protein. Protein deficiency and malnutrition (PEM) can lead to variety of ailments including Intellectual disability and kwashiorkor . Symptoms of kwashiorkor include apathy, diarrhea, inactivity, failure to grow, flaky skin, fatty liver, and edema of
12305-506: The species concept and making taxonomy unstable. Yet others defend this approach, considering "taxonomic inflation" pejorative and labelling the opposing view as "taxonomic conservatism"; claiming it is politically expedient to split species and recognise smaller populations at the species level, because this means they can more easily be included as endangered in the IUCN red list and can attract conservation legislation and funding. Unlike
12420-537: The temperate zone because of its trailing habit and showy, bi-colored tubular flowers, which appear in summer and autumn. The sepals are orange-red, while the petals are bright yellow. In areas prone to frost, some protection is required in winter. The cultivar T. tuberosum var. lineamaculatum 'Ken Aslet' has gained the Royal Horticultural Society 's Award of Garden Merit . Mashua has putative anaphrodisiac effects. It has been recorded by
12535-485: The theoretical difficulties. If species were fixed and clearly distinct from one another, there would be no problem, but evolutionary processes cause species to change. This obliges taxonomists to decide, for example, when enough change has occurred to declare that a lineage should be divided into multiple chronospecies , or when populations have diverged to have enough distinct character states to be described as cladistic species. Species and higher taxa were seen from
12650-877: The time of Aristotle until the 18th century as categories that could be arranged in a hierarchy, the great chain of being . In the 19th century, biologists grasped that species could evolve given sufficient time. Charles Darwin 's 1859 book On the Origin of Species explained how species could arise by natural selection . That understanding was greatly extended in the 20th century through genetics and population ecology . Genetic variability arises from mutations and recombination , while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures . Genes can sometimes be exchanged between species by horizontal gene transfer ; new species can arise rapidly through hybridisation and polyploidy ; and species may become extinct for
12765-493: The vitamin C levels in yellow mashua tubers range from 0.53 to 1.54 mg/g dry matter. The tubers that display both yellow and purple hues demonstrate a considerably higher vitamin C concentration, with a range of 0.9 to 3.36 mg/g dry matter. In comparison, potatoes, a more commonly known tuber, have a lower vitamin C content, with a range of 0.27 to 0.87 mg/g dry matter. This indicates that mashua can contain approximately two to four times more vitamin C than potatoes. Like vitamin C,
12880-564: The vitamin content, also varies according to the cultivation site and genotype. The table delineates the mineral content corresponding to each genotype. Notably, there is a pronounced disparity among the genotypes. Specifically, purple tubers exhibit calcium levels that are 3 to 4 times higher and iron levels that exceed those of other varieties by more than a factor of 200. Conversely, these tubers possess only negligible quantities of potassium and phosphorus , and their zinc levels are comparatively lower. This marked differentiation underscores
12995-540: The wild. It is difficult to define a species in a way that applies to all organisms. The debate about species concepts is called the species problem. The problem was recognised even in 1859, when Darwin wrote in On the Origin of Species : I was much struck how entirely vague and arbitrary is the distinction between species and varieties. He went on to write: No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of
13110-572: The year 2000 as "the true protein absorbed by the intestine, supplied by microbial protein and undegraded intake protein". The limitations of the Kjeldahl method were at the heart of the Chinese protein export contamination in 2007 and the 2008 China milk scandal in which the industrial chemical melamine was added to the milk or glutens to increase the measured "protein". The most important aspect and defining characteristic of protein from
13225-440: The α-linolenic acid (omega-3) is 2.2 and therefore in the optimum range. Mashua is considered a good source of carbohydrates . The carbohydrate content of the dry weight of mashua is between 69.7 - 79.5%, depending on factors like growing conditions and variety of mashua species. It primarily comprises starch , which manifests in the form of grains. These starch grains comprise 27% amylose and 73% amylopectin , contributing to
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