On the mutual polarization of nearby pairs of fucaceous eggs☆

[摘要] Wehavemeasuredthemutualpolarizationofpopulationsofpairsoffucaceouseggsasafunctionoftheirdistanceapart.Wedidthisindifferentcircumstances,ofwhichthemedium'spHandwashingoftheeggsprovedmostconsequential.Undercircumstancesinwhicheacheggtendstoinitiateitsrhizoidpole(orgerminate)towardtheother,italsotendstoinitiateittowardtheother'srhizoidinitial;however,whenittendstogerminateawayfromtheother,itsgerminationdirectionisindependentoftheother's.Weinferthatrhizin(anextracellularlocallyeffectivestimulatorofrhizoidinitiation)isconcentratednearthedevelopingrhizoidinitialandisthusalinkinaregenerativeprocessthatirreversiblypolarizestheegg;however,antirhizin(anextracellularlocallyeffectiveinhibitorofrhizoidinitiation)isinferredtobeuniformlyemittedbyeacheggandthusonlymodifiesthisprocess.Wheneggsinteractthroughantirhizin,theirmutualpolarizationapproximatesthefractionalgradientscalculatedtobeimposeduponeachotherbysynchronoussphericalsourcesofastablestuffinthesteadystate;soantirhizininteractionisinferredtohavethissimplecharacter.However,wheneggsinteractthroughrhizin,theirpolarizationgreatlyexceedssuchgradients;weinferasynchrony,i.e.,thatthefastercellineachpairsendsrhizintotheother,sloweronebeforethislatterstartstoemitit.Theseinferences,inturn,arebelievedtoconfirmrhizinasalinkinthepolarizationprocess,andantirhizinasonlyamodifierofit.Aflowofthemediumthroughthesubstratumandthusbetweenpairsinteractingviarhizinfailstomodifytheirinteractionatspeedsofupto2μ/sec;itisinferredthatrhizinhasadiffusionconstantoftheorderof10−5cm2/secandthusisarelativelysmallmolecule.

[学科分类] 生物科学（综合）