PCR / Molds and Yeasts - Research Paper Example

POLYMERASE CHAIN REACTION AND FUNGI PCR PCR is an abbreviation for polymerase chain reaction which is an in vitro diagnostic technique used to amplify small amounts of DNA such as a drop of blood in hematology called oligonucleotides into large quantities that can be used for identification of specific gene sequences such as those for viral infections (Herrington, 1998,pg.31). In the process primers of DNA in a di-cationic buffer of magnesium chloride are used in combination to dinucleotide triphosphates building blocks in an enzymatic reaction catalyzed by special DNA polymerase to generate huge amounts of DNA from specimen target for further testing or identification (Arnheim, 1991, pg.53). The process involves denaturation of sample DNA at high temperature of 90 to 94 degree centigrade which cannot be withstood by human DNA polymerase followed by annealing of segments at 20 to 45 degrees centigrade using the dNTP and finally extension of form double strand DNA at about 72 degrees Celsius (Herrington, 1998, pg.44).Enzyme in PCRPolymerase chain reaction is catalyzed by a thermo stable DNA polymerase called Taq polymerase which is isolated from Thermus aqaticus, a thermophilic organism discovered by Kary Mullis in the 1980s (Arnheim, 1991,pg.64). It assembles the denatured DNA from deoxynucleotide template substrates from 5’ to 3’ end but lacks the normal exonuclease activity of proofreading.

Function of DNA polymerase in the cellThe enzyme DNA polymerase in the cell catalyzes the assembling of nucleotides which are building blocks of DNA by reading the existing DNA strand to create two complementary strands.PCR changing microbiologyPCR has revolutionized the diagnostic processes in microbiology in a number of ways. It is faster testing technique taking a maximum of one day to produce result (Herrington, 1998, pg.65). It is highly specific thus sensitive for the testing of many genomic diseases (Arnheim, 1991, pg.68). It has been applied in the testing of viral diseases like HIV most sensitively.

Today most viruses are detected efficiently and even Chlamydia and Neisseria species.Similarities and differences between molds and moldsA mycological comparison between the two reveals that they both have egosterol cell wall and are able to withstand acidic conditions (Taro, 2005, pg.45). Both are fungi and are aerobic. They both reproduce asexually. However they have a number of differences. Whereas fungi are unicellular mycoses whether spherical or ellipsoidal in shape producing by budding, molds are multicellular comprising of mycelia and spores which are found in the thali (Kavanagh, 2007, pg.37). Molds are filamentous with elongations known as hyphae from which spores’ form which germinate later to germ tubes to pseudo hyphae or invariably into pseudo mycelia.

Some molds can reproduce sexually by conjugation unlike the yeasts that dominantly propagate by budding. Yeasts may have false processes called pseudo hyphae but do not grow hyphae like molds.Characteristics of given classes of fungiHuman infectious fungal diseases can be superficial, cutaneous, subcutaneous and systemic. Superficial fungi infect the skin, hair and nails (Kavanagh, 2007, pg. 65). These are the dematophytes. They confine themselves to these outermost layers and no host cell mediated or responses by inflammation activated and are more of a cosmetic problem.

Cutaneous fungi infect the keratin of nails, the skin and hair causing patchy scaling and even eczema and thus referred to as dermatomycoses. They have high affinity for the cornified layer (Taro, 2005, pg.51). Subcutaneous fungi on the other hand infect deeper layers of dermatome and mostly are from accidental inoculation of their spores due to trauma or in severe immunosuppression and exhibit characteristic reaction of tissue or granule. Systemic fungi are disseminated deep tissue attacks affecting organs systems and tissues especially histoplasmosis and coccidiodomycosis and are mostly opportunistic to HIV/AIDs infection (Kavanagh, 2007, pg.73).Regions infected by fungiFungal infections infect the groin, the chin, skin, hair, nails, between fingers and oraesophageal region.

They can be thus named according to area they infect as tinea barbae, tinea capitis, tinea manuum, tinia ungium and oncomycoses (Taro, 2005, pg.53).ReferencesArnheim, N. (1991). Polymerase chain reaction. San Diego: Academic Press. Herrington, C. S. (1998). PCR: 3. Oxford: Oxford Univ. Pr. Kavanagh, K. (2007). New insights in medical mycology. Dordrecht: Springer. Talaro, K. P. (2005). Foundations in microbiology. Dubuque, IA: McGraw-Hill.