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Body Odor And Sexual Attraction
Odour is sensory stimulation of the olfactory membrane of the nose by a group of molecules. Certain body odours are connected to human sexual attraction. Humans can make use of body odour subconsciously to identify whether a potential mate will pass on favourable traits to their offspring. Body odour may provide significant cues about the genetic quality, health and reproductive success of a potential mate. Body odour affects sexual attraction in a number of ways including through human biology, the menstrual cycle and fluctuating asymmetry. The olfactory membrane plays a role in smelling and subconsciously assessing another human's pheromones. It also affects the sexual attraction of insects and mammals. The major histocompatibility complex genes are important for the immune system, and appear to play a role in sexual attraction via body odour. Studies have shown that body odour is strongly connected with attraction in heterosexual females. The women in one study ranked body odo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Odor
Body odor or body odour (BO) is present in all animals and its intensity can be influenced by many factors (behavioral patterns, survival strategies). Body odor has a strong genetic basis, but can also be strongly influenced by various factors, such as sex, diet, health, and medication. The body odor of human males plays an important Body odour and sexual attraction, role in human sexual attraction, as a powerful indicator of Major histocompatibility complex, MHC/Human leukocyte antigen, HLA heterozygosity. Significant evidence suggests that women are attracted to men whose body odor is different from theirs, indicating that they have immune genes that are different from their own, which may produce healthier offspring. Causes In humans, the formation of body odors is caused by factors such as diet, sex, health, and medication, but the major contribution comes from bacterial activity on skin gland secretions. Humans have three types of sweat glands: eccrine sweat glands, apocri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigen Presentation
Antigen presentation is a vital immune process that is essential for T cell immune response triggering. Because T cells recognize only fragmented antigens displayed on cell surfaces, antigen processing must occur before the antigen fragment can be recognized by a T-cell receptor. Specifically, the fragment, bound to the major histocompatibility complex (MHC), is transported to the surface of the antigen-presenting cell, a process known as presentation. If there has been an infection with viruses or bacteria, the antigen-presenting cell will present an endogenous or exogenous peptide fragment derived from the antigen by MHC molecules. There are two types of MHC molecules which differ in the behaviour of the antigens: MHC class I molecules (MHC-I) bind peptides from the cell cytosol, while peptides generated in the endocytic vesicles after internalisation are bound to MHC class II (MHC-II). Cellular membranes separate these two cellular environments - intracellular and extracell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androstenone
Androstenone (5α-androst-16-en-3-one) is a 16-androstene class steroidal pheromone. It is found in boar's saliva, celery cytoplasm, and truffle fungus. Androstenone was the first mammalian pheromone to be identified. It is found in high concentrations in the saliva of male pigs, and, when inhaled by a female pig that is in heat, results in the female assuming the mating stance. Androstenone is the active ingredient in 'Boarmate', a commercial product made by DuPont sold to pig farmers to test sows for timing of artificial insemination. Biosynthesis Androstenone is synthesized from androstadienone by 5α-reductase, and can be converted into 3α-androstenol or 3β-androstenol by 3-ketosteroid reductase. Properties Depending upon the subject, androstenone can have an unpleasant, sweaty, urinous smell, a woody smell, or even a pleasant floral smell. There are two different genotypes that allow an individual to smell androstenone. The first genotype, which consists of two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigen
In immunology, an antigen (Ag) is a molecule, moiety, foreign particulate matter, or an allergen, such as pollen, that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. Antigens can be proteins, peptides (amino acid chains), polysaccharides (chains of simple sugars), lipids, or nucleic acids. Antigens exist on normal cells, cancer cells, parasites, viruses, fungus, fungi, and bacteria. Antigens are recognized by antigen receptors, including antibodies and T-cell receptors. Diverse antigen receptors are made by cells of the immune system so that each cell has a specificity for a single antigen. Upon exposure to an antigen, only the lymphocytes that recognize that antigen are activated and expanded, a process known as clonal selection. In most cases, antibodies are ''antigen-specific'', meaning that an antibody can only react to and bind one specific antigen; in some instances, however, antibodies may cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterozygote Advantage
A heterozygote advantage describes the case in which the heterozygous genotype has a higher relative fitness (biology), fitness than either the homozygous Dominance (genetics), dominant or homozygous recessive gene, recessive genotype. Loci exhibiting heterozygote advantage are a small minority of loci. The specific case of heterozygote advantage due to a single locus (genetics), locus is known as overdominance. Overdominance is a rare condition in genetics where the phenotype of the heterozygote lies outside of the phenotypical range of both homozygote parents, and heterozygous individuals have a higher fitness (biology), fitness than homozygous individuals. Polymorphism (biology), Polymorphism can be maintained by Natural selection, selection favoring the heterozygote, and this mechanism is used to explain the occurrence of some kinds of genetic variation, genetic variability. A common example is the case where the heterozygote conveys both advantages and disadvantages, while bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androstenone
Androstenone (5α-androst-16-en-3-one) is a 16-androstene class steroidal pheromone. It is found in boar's saliva, celery cytoplasm, and truffle fungus. Androstenone was the first mammalian pheromone to be identified. It is found in high concentrations in the saliva of male pigs, and, when inhaled by a female pig that is in heat, results in the female assuming the mating stance. Androstenone is the active ingredient in 'Boarmate', a commercial product made by DuPont sold to pig farmers to test sows for timing of artificial insemination. Biosynthesis Androstenone is synthesized from androstadienone by 5α-reductase, and can be converted into 3α-androstenol or 3β-androstenol by 3-ketosteroid reductase. Properties Depending upon the subject, androstenone can have an unpleasant, sweaty, urinous smell, a woody smell, or even a pleasant floral smell. There are two different genotypes that allow an individual to smell androstenone. The first genotype, which consists of two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androstenol
Androstenol, also known as 5α-androst-16-en-3α-ol (shortened to 3α,5α-androstenol or 3α-androstenol), is a 16-androstene class steroidal pheromone and neurosteroid in humans and other mammals, notably pigs. It possesses a characteristic musk-like odor. Androstenol, or a derivative, is found in black truffles. This was offered as an explanation for how pigs locate them deep in the ground: Androstenol is produced in the saliva of male pigs. However, experiments in France using pigs to scent truffles, truffle scent extract, and purified androstenol showed that pigs responded to the first two (actually trying to eat dirt containing the truffle extract), but ignored the androstenol. A stereoisomer of androstenol, 3β-androstenol (5α-androst-16-en-3β-ol), is also endogenous to humans (as well as to pigs), behaving as a pheromone and contributing to axillary odor. Biosynthesis In humans and boars, androstenol is biosynthesized in the testes. Pregnenolone is metabolized into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pheromone
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavior of the receiving individuals. There are ''alarm signal, alarm pheromones'', ''food trail pheromones'', ''sex pheromones'', and many others that affect behavior or physiology. Pheromones are used by many organisms, from basic unicellular prokaryotes to complex multicellular eukaryotes. Their use among insects has been particularly well documented. In addition, some vertebrates, plants and ciliates communicate by using pheromones. The ecological functions and evolution of pheromones are a major topic of research in the field of chemical ecology. Background The portmanteau word "pheromone" was coined by Peter Karlson and Martin Lüscher in 1959, based on the Greek language, Greek () and (). Pheromones are also sometimes classified as ec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3α-androstenol
Androstenol, also known as 5α-androst-16-en-3α-ol (shortened to 3α,5α-androstenol or 3α-androstenol), is a 16-androstene class steroidal pheromone and neurosteroid in humans and other mammals, notably pigs. It possesses a characteristic musk-like odor. Androstenol, or a derivative, is found in black truffles. This was offered as an explanation for how pigs locate them deep in the ground: Androstenol is produced in the saliva of male pigs. However, experiments in France using pigs to scent truffles, truffle scent extract, and purified androstenol showed that pigs responded to the first two (actually trying to eat dirt containing the truffle extract), but ignored the androstenol. A stereoisomer of androstenol, 3β-androstenol (5α-androst-16-en-3β-ol), is also endogenous to humans (as well as to pigs), behaving as a pheromone and contributing to axillary odor. Biosynthesis In humans and boars, androstenol is biosynthesized in the testes. Pregnenolone is metabolized into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptide
Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. Peptides fall under the broad chemical classes of biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, to another protein or other macromolecule such as DNA or RNA, or to complex macromolecular assemblies. Amino acids that have been incorporated into peptides are termed residues. A water molecule is released during formation of each amide bond.. All peptides except cyclic peptides have an N-terminal (amine group) and C-terminal (carboxyl g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Complex
A protein complex or multiprotein complex is a group of two or more associated polypeptide chains. Protein complexes are distinct from multidomain enzymes, in which multiple active site, catalytic domains are found in a single polypeptide chain. Protein complexes are a form of protein quaternary structure, quaternary structure. Proteins in a protein complex are linked by non-covalent interactions, non-covalent protein–protein interactions. These complexes are a cornerstone of many (if not most) biological processes. The cell is seen to be composed of modular supramolecular complexes, each of which performs an independent, discrete biological function. Through proximity, the speed and selectivity of binding interactions between Enzyme, enzymatic complex and substrates can be vastly improved, leading to higher cellular efficiency. Many of the techniques used to enter cells and isolate proteins are inherently disruptive to such large complexes, complicating the task of determining ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inbreeding Avoidance
Inbreeding avoidance, or the inbreeding avoidance hypothesis, is a concept in evolutionary biology that refers to the prevention of the harmful effects of inbreeding. The inbreeding avoidance hypothesis posits that certain mechanisms develop within a species, or within a given population of a species, as a result of assortative mating and natural selection, natural and sexual selection, in order to prevent breeding among related individuals. Although inbreeding may impose certain evolutionary costs, inbreeding avoidance, which limits the number of potential mates for a given individual, can inflict opportunity costs. Therefore, a balance exists between inbreeding and inbreeding avoidance. This balance determines whether inbreeding mechanisms develop and the specific nature of such mechanisms. Inbreeding can result in inbreeding depression, which is the reduction of Fitness (biology), fitness of a given population due to inbreeding. Inbreeding depression occurs via appearance of di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
