Page 376 - konishipaper

ELSEVIER
Cryobiology73(2016)30-39 ContentslistsavailableatScienceDirect Cryobiology
journal homepage:w w w.elsevier.comハocate/ycryo
Efectsofmicroelectriccurentloadduringcolingofplanttisueson intracelularicecrystalformationbehaviorandpH
TakakoNinagawaa，Yukio1くawamu日 b，TadashiKonishic，AkiraNarumia司，
aGraduateScholofMechanicalEngineering，IGロnagawalnsti印 teofTechnology，1030Shimo-ogino，Atsugi，Kanagawロ243-0292，]apan bCryobiofrontierResearchCente，rFa口lityofAgri印 l印 re，lwateUniversity，Ueda3-18-8，Mo吋iok口，lwate020-8550，]apan cDepartmentofMechanicalEnginering，OitaNロtionalColegeofTechnology，16Maki，Oi臼，870-0152，]ロpan
CrosMark
ARTICLE INFO
Artic/ehistory: Received30November2015 Receivedinrevisedform 9June2016 Acepted20June2016 Availableonline21June2016
Keywords: Electriccurentload Intracelularfrezing Icecrystal Supercoling IntracelularpH Plant
1. Introduction
Atpresent，cryopreservationisanesentialtechniqueinvarious fields， inc1uding food and medical engine ering. Although living materialssuchasfoodandbiologicaltisuecanbepreservedatlow temperature，theyarespontaneouslyfrozenbelowthesolidifica- tionpointbecauseoftheirwatercontentthroughsupercoling. lntracelularfrezingleadstoceldeath[1，14，18，24，28]，anditis believedthaticecrystalsformedbothoutsideandwithinacel causethemolificationoftheplanttisueofvegetablesandfruits [3，8].However，itisdificulttopreventintracelularfrezingin theselivingmaterialsusingcurentcryopreservationtechniques. Therefore，a dream cryopreservation technique would not only
キ Corespondingautho.r
E-mail adreses: 5129101@cco.kanagawa-i.tac.jp 工(
2016ElsevierInc.Alrightsreserved.
preservethelivingmaterialbutwouldalsobeabletokeepitina livingorfreshstateforalongtime[21].
Asthefirststeptoexploretheposibilityofanewcryopreser- vationtechnique，theauthorsconsideredthatitwasimportantto visualizetheintracelularicecrystalformation(IF)behaviorand comprehendthebeginningofintracelularfrezingandtheprog- resofIF.Therefore，theauthorsconstructedanewcryomicro- scopysystem，whichcomprisedaninvertedmicroscope，ahigh- speedcamera，andacolingstage，andthenobservedIFinthe epidermal tisues ofstrawberrygeranium (Saxifraglα stolonifera Curtis)leavesatvaryingcolingratestoevaluatethereleaseof intracelularsupercolingusingthissystem.Fromsubsequentre- sults，increasingthecolingratecausedanincreaseinthedegreeof supercoling，areductioninthedegreeofceldeformation，anda decreaseinthesizeofintracelularicecrystalgrains[21].
Next，theauthorsfocusedonthefrezingtoleranceofplantsto exploretheposibilityofanewcryopreservationtechnique.Some plantsacquirefrezingtolerancetosurviveinseverewinterby beingexposedtolowtemperatures[4，9，10].Plantcelsthatacquire
Ninagawa)，ykawa@ iwate-u.ac.jp(Y. Kawamura)，konishi@oita-ct.aιjp(T.Konishi)，narul1i@me
kanagawa-it.ac.jp(A.Narumi).
htp:fdx.doi.orgf10.1016fj.cryobio.l2016.06.002
0 01 1-2 240f@ 2016ElsevierInc.Al lrightsreserved.
ABSTRACT
Cryopreservationtechniquesareexpectedtoevolvefurthertopreservebiomaterialsandfodsinafresh stateforextendedperiodsoftime.Long-termcryopreservationoflivingmaterialssuchasfodand biological tis sue is general ly achieved by fre ezing; thus， intracel lular fre ezing oc curs.Intracel lular frezinginjuresthecelsandleadstoceldeath.Therefore，adreamcryopreservationtechniquewould preservethelivingmaterialswithoutinternalicecrystalformationatatemperaturelowenoughto preventbacterialactivity.Thisstudywasperformedtoinvestigatetheefectofmicroelectricalcurent loadingduringcolingasanewcryopreservationtechnique.Thebehaviorofintracelularicecrystal formationinplanttisueswithorwithoutanelectriccurentloadwasevaluatedusingthedegreof supercoling，degreofceldeformation，andgrainsizeandgrowingrateofintracelularicecrysta.l Moreover，thetransitionofintracelularpHduringplanttisuecolingwithorwithoutelectriccurent loadingwasalsoexaminedusingthefluorescenceintensityratiotocomprehendcelactivityatlower temperatures.Theresultsindicatedthatmicroelectriccurentloaddidnotonlydecreasethedegreof celdeformationandgrainsizeofintracelularicecrystalbutalsoreducedthedeclineinintracelularpH duetotempera回 relowering，comparedwithtisuessubjectedtothesamecolingratewithoutan electriccurentload.Thus，theefectofelectriccurentloadoncryopreservationandthepotentialofa newcryopreservationtechniqueusingelectriccurentloadwer。ediscusedbasedontheseresults.