|
Hair Perforation Test
The hair perforation test, also known as an ''in vitro'' hair perforation test, is a laboratory test used to help distinguish the isolates of dermatophytes, such as ''Trichophyton mentagrophytes'' and its variants. The test is performed by placing an organism into a Petri dish containing water, yeast extract, and hair. After incubation for 4 week, they are examined under microscopy T.mentagrophyte would have produced erosions on the Hair while T. Rubrum will not produce any change. Hence they are used to differtiate dermatophytes. The Mayo Clinic's mycology laboratory has identified five common dermatophytes; '' Microsporum gypseum'', ''Microsporum canis'', ''Trichophyton rubrum'', ''Trichophyton mentagrophytes'', and ''Trichophyton tonsurans ''Trichophyton tonsurans'' is a fungus in the family Arthrodermataceae that causes ringworm infection of the scalp. It was first recognized by David Gruby in 1844. Isolates are characterized as the "–" or negative mating type of the '' Art ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Isolate
Introduction Geographic isolation or other factors that prevent reproduction have resulted in a population of organisms with a change in genetic diversity and ultimately leads to the genetic isolation of species. Genetic isolates form new species through an evolutionary process known as speciation. Today, all the species diversity present on earth is the product of genetic isolate and evolution. The current distribution of genetic differences and isolation within and among populations is also influenced by genetic processes, which can give significant input into evolution's basic principles. The resulting genetic diversity within a species' distribution range is frequently unequally distributed, and large disparities can occur at the series of ranges when population dispersion and isolation are critical for species survival. The interrelationship of genetic drift, gene flow, and natural selection determines the level and dispersion of genetic differences between populations and am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dermatophytes
Dermatophyte (from Greek '' derma'' "skin" ( GEN ''dermatos'') and ''phyton'' "plant") is a common label for a group of fungus of '' Arthrodermataceae'' that commonly causes skin disease in animals and humans. Traditionally, these anamorphic (asexual or imperfect fungi) mold genera are: '' Microsporum'', '' Epidermophyton'' and '' Trichophyton''. There are about 40 species in these three genera. Species capable of reproducing sexually belong in the teleomorphic genus Arthroderma, of the Ascomycota (see Teleomorph, anamorph and holomorph for more information on this type of fungal life cycle). As of 2019 a total of nine genera are identified and new phylogenetic taxonomy has been proposed. Dermatophytes cause infections of the skin, hair, and nails, obtaining nutrients from keratinized material. The organisms colonize the keratin tissues causing inflammation as the host responds to metabolic byproducts. Colonies of dermatophytes are usually restricted to the nonliving cornifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichophyton Mentagrophytes
''Trichophyton mentagrophytes'' is a species in the fungal genus '' Trichophyton''. It is one of three common fungi which cause ringworm in companion animals. It is also the second-most commonly isolated fungus causing tinea infections in humans, and the most common or one of the most common fungi that cause zoonotic skin disease (i.e., transmission of mycotic skin disease from species to species). ''Trichophyton mentagrophytes'' is being frequently isolated from dogs, cats, rabbits, guinea pigs and other rodents, though at least some genetic variants possess the potential of human-to-human transmission, e.g. Type VII and Type VIII. Particular genetic variants of the fungus have distinct geographic ranges. Drug resistance In ''T. mentagrophytes'', antifungal drug resistance is mainly associated with Type VIII isolates. Drug-resistant ''T. mentagrophytes'' strains have been found in many places across Asia and Europe. India is the most affected country, with the rate of microb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Diversity
Genetic diversity is the total number of Genetics, genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is distinguished from ''genetic variability'', which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals. The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral subs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petri Dish
A Petri dish (alternatively known as a Petri plate or cell-culture dish) is a shallow transparent lidded dish that biologists use to hold growth medium in which cells can be cultured,R. C. Dubey (2014): ''A Textbook Of Biotechnology For Class-XI'', 4th edition, p. 469. originally, cells of bacteria, fungi and small mosses. The container is named after its inventor, German bacteriologist Julius Richard Petri. It is the most common type of culture plate. The Petri dish is one of the most common items in biology laboratories and has entered popular culture. The term is sometimes written in lower case, especially in non-technical literature. What was later called Petri dish was originally developed by German physician Robert Koch in his private laboratory in 1881, as a precursor method. Petri, as assistant to Koch, at Berlin University made the final modifications in 1887 as used today. Penicillin, the first antibiotic, was discovered in 1929 when Alexander Fleming noticed th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mayo Clinic
The Mayo Clinic () is a nonprofit American academic medical center focused on integrated health care, education, and research Research is "creative and systematic work undertaken to increase the stock of knowledge". It involves the collection, organization and analysis of evidence to increase understanding of a topic, characterized by a particular attentiveness t .... It employs over 4,500 physicians and scientists, along with another 58,400 administrative and allied health staff, across three major campuses: Rochester, Minnesota; Jacksonville, Florida; and Phoenix, Arizona, Phoenix/Scottsdale, Arizona. The practice specializes in treating difficult cases through Health care#Tertiary care, tertiary care and Medical tourism#United States, destination medicine. It is home to the top-15 ranked Mayo Clinic Alix School of Medicine in addition to many of the highest regarded residency education programs in the United States. It spends over $660 million a year on research an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsporum Gypseum
''Microsporum gypseum'' is a soil-associated dermatophyte that occasionally is known to colonise and infect the upper dead layers of the skin of mammals. The name refers to an asexual "form-taxon" that has been associated with four related biological species of fungi: the pathogenic taxa '' Arthroderma incurvatum'', ''A. gypsea'', '' A. fulva'' and the non-pathogenic saprotroph ''A. corniculata''. More recent studies have restricted ''M. gypseum'' to two teleomorphic species ''A. gypseum'' and ''A. incurvatum''. The conidial states of ''A. fulva'' and ''A. corniculata'' have been assigned to ''M. fulvum'' and ''M. boullardii''. Because the anamorphic states of these fungi are so similar, they can be identified reliably only by mating. Two mating strains have been discovered, "+" and "–". The classification of this species has been based on the characteristically rough-walled, blunt, club-shaped, multicelled macroconidia. Synonyms include ''Achorion gypseum'', ''Microsporum flave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsporum Canis
''Microsporum canis'' is a pathogenic, asexual fungus in the phylum Ascomycota that infects the upper, dead layers of skin on domesticated cats, and occasionally dogs and humans. The species has a worldwide distribution. Taxonomy and evolution ''Microsporum canis'' reproduces by means of two conidial forms, large, spindle-shaped, multicelled macroconidia and small, single-celled microconidia. First records of ''M. canis'' date to 1902. Evolutionary studies have established that ''M. canis'', like the very closely related sibling species ''M. distortum'' and ''M. equinum'', is a genetic clone derived from the sexually reproducing species, ''Arthroderma otae''. Members of Ascomycota often possess conspicuous asexual and sexual forms that can coexist in time and space. ''Microsporum canis'' exemplifies a common situation in ascomycetous fungi in which, over time, one mating type strain has undergone habitat divergence from the other and established a self-sustaining reproductive p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichophyton Rubrum
''Trichophyton rubrum'' is a dermatophytic fungus in the phylum Ascomycota. It is an exclusively clonal, anthropophilic saprotroph that colonizes the upper layers of dead skin, and is the most common cause of athlete's foot, fungal infection of nail, jock itch, and ringworm worldwide. ''Trichophyton rubrum'' was first described by in 1845 and is currently considered to be a complex of species that comprises multiple, geographically patterned morphotypes, several of which have been formally described as distinct taxa, including ''T. raubitschekii'', ''T. gourvilii'', ''T. megninii'' and ''T. soudanense''. Growth and morphology Typical isolates of ''T. rubrum'' are white and cottony on the surface. The colony underside is usually red, although some isolates appear more yellowish and others more brownish. ''Trichophyton rubrum'' grows slowly in culture with sparse production of teardrop or peg-shaped microconidia laterally on fertile hyphae. Macroconidia, when present, are smooth-wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichophyton Tonsurans
''Trichophyton tonsurans'' is a fungus in the family Arthrodermataceae that causes ringworm infection of the scalp. It was first recognized by David Gruby in 1844. Isolates are characterized as the "–" or negative mating type of the '' Arthroderma vanbreuseghemii'' complex. This species is thought to be conspecific with '' T. equinum'', although the latter represents the "+" mating strain of the same biological species Despite their biological conspecificity, clones of the two mating types appear to have undergone evolutionary divergence with isolates of the ''T. tonsurans''-type consistently associated with Tinea capitis (particularly in children) whereas the ''T. equinum''-type, as its name implies, is associated with horses as a regular host. Phylogenetic relationships were established in isolates from Northern Brazil, through fingerprinting polymorphic RAPD and M13 markers. There seems to be lower genomic variability in the ''T. tonsurans'' species due to allopatric div ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
