Photonic crystals in biology - NanoTR-VI

Poster Session, Thursday, June 17Theme F686 - N1123Effects of dehydrating conditions on Dermatophagoides farina and Dermatophagoides pteronyssinusNada O. EdreesDepartment of Biology, Faculty of Sciences for Girls, king Abdelaziz university .Jeddah , Kingdom of Saudia arabiaE-mail : nada_algalb@hotmail.comnedrees@kau.edu.saAbstractHouse dust mites have lived in human contact from time immemorial dander or dead skin constitutes the major organiccomponent of house dust ecosystem . Because the mites feed on dander , dust mite and human association will continue to coexist as part of our environment . Efficient house – draying practice is the best form of control to reduce infestation , keepinghome dray ( Nadchatram , 2005). Sensitization and development of allergic respiratory disease result from complex genetic andenvironmental interactions . Specific measures to reduce indoor allergen exposure when vigorously applied may reduce the riskof sensitization and symptoms of allergic respiratory disease (Bush , 2008) . Survival experiments with D.farnae andD.pteronyssinus were. In environments containing water vapor below the CEA , more water is transpired than absorbed from theatmosphere and thus dehydration occur . An increase in temperature seems to increase the rate of dehydration . When exposed todehydrating condition (35% , 25% ,15% RH) . D.pteronyssinus and D.farinae exhibited increase mortality in response to anincrease of temperature . The lower mortality for males may be accounted for by their larger surface area to volume ratio , whichresult in transpiration occurring at a greater rate than in females .Key word: Dermatophagoides pteronyssinus , Dermatophagoides farina , humidity, dehydration , saudia Arabia .IntroductionThe house dust mite Dermatophagoides farinae ,Dermatophagoides pteronyssinus are the major sources of indoor allergensand are therefore considered important health problems worldwide . Many allergic individuals (hay fever , asthma , atopicdermatitis ) are sensitive to these mite ( Adgate , et al ,2008 ; Van Gysel et al , 2007, Edrees ,2008d) The worm , humidenvironment in modern homes favours the dust mite population , most homes contain one or more species of these house dustmite (Wu et al , 2009) . Carpets , mattresses , bedding , pillows, pillow covers , and clothing may contain breeding populationof house dust mite . Saudi Arabia is a fast developing country situated in the middle of the Arabian Peninsula . Due to thevariation in geography and climate . Particularly humidity of the regions which vary significantly . Riyadh in the central regionis considered to have low humidity . While humidity in western coastal region , Jeddah and southern region of Abha iscomparatively higher . which helps house dust mites thrive , in autumn and winter not during summer specially in Jeddah due tothe increasing of temperature up to 50°C (Edrees , 2009) .In Jeddah most homes contain both D.farinae ,D.pteronyssinus (Edrees,2006,2008 a,b,c). However , special precautions areimportant when individuals are susceptible or sensitive to house dust mite .This the extremely important for a possible integratedcontrol that can be taken to eliminate house dust mite and their allergens from the indoor environment .Most adult of D.farinaeand all adult of D.pteronyssinus cannot survive when exposed to 45°c for at least 48hr . Dehydration and survival of the housedust mite D.farinae and D.pteronyssinus at specific ambient conditions , was undertaken to determine the possibility oftemperature and humidity manipulation as a natural control method (Arlian 1975 , Brandt & Arlian ,1976). The purpose of thisstudy was to systematically investigate survival of D.pteronyssinus and D.farinae Exposure to specific relative humidity andtemperatures , determine whether these additives would increase mortalities during dehydration .Matrrial and mehodD.farinae and D.pteronyssinus used for experimentation were obtained from thriving pure laboratory culture at 75% RH and25°C , as described by Arlian (1975) incubator to provide the desired temperature . the critical equilibrium activity(CEA) of adultfemales to be 0.70 and 0.73 (70% and 73%RH) , respectively , (Robert ,et al 1976) .Statistical analysis :The data in tables ( 1 , 2 ,3) are presented as mean ± . The statistical analysis between the mites species andthe different six of each species were performed using paring " t – test " (Armitage , 1974 ) . All statistical were computed bySPSS 14 .Exposure to specific relative humidity and temperatures : Survival experiments with D.farnae and D.pteronyssinus wereconducted by placing 10 adults of 1 sex together in a glass vial containing a sufficient amount of yeast for food. Eight to 15 vials(100 mite) were used per experiment . The vials were constructed from 5 mm diam. X 20 mm lengths of glass tubing . To confinethe mite , the ends were plugged with a nylon mesh screen by inserting a Teflon washer into each end of the cage . An averagedistance of 10 mm was maintained between the plugs . After being equilibrated at 25°C and 75% RH for 24 hr , the vials weresuspended in closed ,4-oz(0.12-liter)bottles containing the appropriate glycerol solution to maintain the desired test RH'S. In turn, these bottles were placed in a BOD (Biochemical Oxygen Demand ) incubator to provide the desired temperature . Survivalcounts were made every 42 hr until 100%mortality was achieved (Robert et al ., 1976) . In this study the relative humidity isrecorded after each 48 it showed gradually decreasing (75% RH , 65% RH , 55% RH , 45% RH , 35 RH %,25 RH %, 15% RH ), during the gradually increasing of temperature( 32°C , 37°C , 42°C, 44°C , 46°C , 48°C , 50°C ) .RESULTSIncreasing in mortality is recorded gradually by increasing temperature which consequently lead to decrease thehumidity as a result of dehydration, the investigation had been recorded each 48 hours to count the survival mites . Thecalculated of mortality and survival in test population male, at specific time intervals when exposed to various temperature andhumidity were shown in tables. male have tolerated desiccation better than fmales at all RH tested at all temperature regimestested( tables 1,2,3) .6th Nanoscience and Nanotechnology Conference, zmir, 2010 817