Document GKG08djMNXb5BN2LOxkjyz54n

0 ............. . (SC 5 r^n hrtin in icrjuiinilisl ml the ni'iipMnl rclmst'il attiiehrd liy ihr plmnyl.'dauyl HINA simply l.y M.u vin- f;mn tlic rit.i>>ij:iiv/KNA n implex to which i*. is hound for thrcoiiin.'. Willi this ho has been nidi' lo deim.i' the by ilm iwikt'itk' carrying the kr-t nn.inu-aci.l cinidirimis nccesrury for trniiimunm; mrim.uiii;.; ihr iiKorjiitnU' d. There must, lie n merlinnirm tar rvndin nunph'x under suitable condition* with or will: thcrhiim icivt-inaling coiloit j[tliifttcodotM b'AA, UAG, tiiivoniim or supernatant eiv/.yines sltov.'id that to yet- find UW/Vrort tide for chum termination) mel i-lravin;* release it is iiotv: >ury Imt. not suftieient to complete tin- llie Just jt' j.li lvl.M'XA bund. in iiUrrhim Hiuphy*. peptide Jiy incur] mruling tluwiiino luul that ndetev /.'<,t. CVw/iw., 77.1 (Iil(i7) /ic(!c}*(TilKwn experimental is not solely deprmh-iit on the transfer cur,} im-s system devised togivun rapid assay for Hinin trrminn- required to uioit the ribo*sinn'from Ihc tliriwyl m-fun tio.'i, Mid in /Vw. (if1 Xtil. Aru1!. tier., 53, ll-! l (HKiV) (i) the UACJ (criiimating eoilon. Helens/*dovs,however, In- reports the dimivery of tin enzyme required for depend upon the presence of a supernatant factor. T'lnV, tenniiuilion. - fuctor, with a muleriihir weight of between lO.Ci'u and 'Jiio away for Wminutitm employs tin* UNA from f.t),0(X>. Pediments between 3-iiA and 4-oV. Ureame i*-- ttn nmW'r mutant of the coat protein "one of the UNA releasing nrisriu- is not afleeted by RXasc, it ciumnl bacteriophage 7/17. Tliid mutant has an amber codon, beanP.XA-protein complex. Apparently the substrate' l/ACJ, at Hip position of the sixth inino-neid, a gtnt. .of the release enzyme is the libosoiwe-tnRXA-peptidyl mine residue. in the 7/17 coat protein.molecule. Jn a i ItXA complex v.i that it must act- directly c.1 thu ribo eelI free system the mutant UNA directs tin- ay-nlli'isds some and not cleave the /RXA from pcptidyl-lRXA of a wnnli X-fermiiial pr*jtiili' of the eoat protein with already released into (ha supernatant, which was thu the sequence X-i'orinylimd-uia-ver-uspn-phe-Uir: the other possibility. .* ncxt.Aininn-Arid In the coal protein is "hdiimuio, hut Capecchi does not yet-know whether the release with the* mutant UNA the timber codon emmes pre enzyme works clone nr in conjunction with or her factor*, mature tumin.Vihm of r-ynlJuris end the relituteeC the in particular a hypothetical chain termination /ItXA* he\a|<epl!iJe. The great virtue of t.his system is that which roads the tVriainutinn codon but does not tarry till1 unlerminiited peptide still attached to the jieptidyl- an amino-acid. Many people, including Capccchi, hare /UNA can he distinguished from the terminated peptide searched in vain fur such u Il'XA specie?, and although rehitsed firun (he /UNA nnd the amounts of each negative results cun never exclude the possibility thai uieamrrd. Furthermore, starving the system for any one such /HXA exists it is reasonable to think about of the six nmino-nriils in the peptide arrest* tlic trans alternative mwlels in wliich tho terminating ccnion:! lation mnehinwy before it reaches the UA(I codon so mu' road cither hy riie ribosome or tlic release enzyme Irrmination '.-sit bo controlled, .. or in which nriusense'cfidnns funetiou-wmph' because Exploiting thi* procedure, Capcechi isolated a they cannot be rend at all. Further characterization loinjiii-x of ribosome, wiltXA and pentapeptide of the release enzyme could well decide the issue. Chlorinated Hydrocarbons in British Wildlife by . 0. C. HOIKFS ' 1 ). H. SiMNONS J. O'G. TATTC-N * t-r.borjlpry of ih* Government Cl-emiu, Lontfen Polychlorobiphcnyl compounds have been detected In British wildlife. In birds' livers and 0gs they are often in greater quantities than organochlorino pesticide residues. Polyehiornbiphcnyls arc known to be toxic, and their detection in witdiifc raises the question of the adverse effect they may have. U lllis m ill I bird;' ip;i nr tli" Iivi-ir of l.niisll u iiMlifc nw> 'xamiiii'd Uy tliiniiuilngi'npliy (Ol.l'J using i-li'Ction-cn|iinii` ili'I'-vlinn, ('Ciriv',jii-.tidii,'r to Kiu-ii i'i}.'ni;i>v!di<iiti> |*,-sl ir-iilrs ns J'H liieldi iii unci DPT, mid tin'll' lueljiln.lil.'r and litvukiU.uii IiiihIik-I,;. rifl' ii p)n*i' m I l.o ri-JiiU.iiit cl'.rniiiiUogmiiK. *hi<-M- p.-itbe. Mii.viimei* i,e|ien*ui aimmnU ttiiicli arc rigiiiffCrtiit ironi :t tiixieulo- yii-al point ofvi.-w, but. the m-u^itiviiv of imidciii iuxliu- i''nin also >'ii,iUo.' cuin]i!otcly iioiiuiiAcniit nmoutits to be dctr-eicd. Aunly<ts cimtviii.'d v.ii!> tli<* tli'ti-mdiMliuii of <'ri,'i.iioel)ltiiiiiv ]>>'-tii;idi'< in v. i'.llil'c, lim\VM-r, li::ve lung lni'ii nivaic tIi ii it in nut iii.h.-imI I'm- iiii niMitirii.ii! si'ti.s or ns many as leu peal:*, e;u-:v-;infiilim.* in iiiiirl>.-nti!icil 'itnjHuiiiil.'!. lO -- i to apjn-ur tui thin.' {,bi,oin:ituj.riln)i,`<. bill I;' is kiiii'.vn i.f i!uv wi'iinlm;' r./.il i.r)^;i f tia-sc ci'iu* l>iimla, but Kuln:ii1 <-MubUi4in! thut they are orgnim clilurinv in natuu', with it Mib-tunliftl, chUu'me roi.tt'i.i. mid cciiisi'tiui'iiily pu.-'sew i-leutKm-uiiitnriug propeities. On fita-ouc ir *Ajikvon' <`.ilimi>ii>. the acri'-s f peaks_for tbe-ie r:ompnu:.is uonually begins at tli'.* point nt wliicti /y>'-TDR uml /yi'-DllT ms* I'melginj; from tl*' enluums pud exlrndx. in t.'noit uf retention lime*, to femr or tivu `linvs that- of ;ip'-])DT, which it the last of tlic cnmuionly fieoiin-ing peri icides to emerge. ' ' Hefui'o examination by <JLC`, wunplc? have iKiinvili'y beeu iiibjccti'd lo a fithly rigorous clean-uri I'mcnhire. Kiieb ns thut of de l-'mili-ut Si'auiidwrto/.5, which iui lnil- * u dimethylriinnantido-lit'Ximi* jxulitiuii mid pi'..igi* through n coiuiun of jirep.ired aiuinina. IVenta** llicve unhiimviv eonit'.nnaU mi* similar in luture ui.il jir,>i'*,ni<' to i In: tirgm.ia-Murinc peiitU'ulcii, they nbi> |i-< riuoiipi: "'liit mid riiii'kV'.eViui-uji |iMitcditr-; conscipirully. they TOWOLDMONOOQ3244 _ . Ml* n'S^RE. VOL. a6. OCTOBER I&S7 oft-i'ij inb-tlnre M-ri.ii:*ly will) ili}tcriniiml.inu>i if /.|/-T1>K unit in wildlife Im-iiuuso of ovnrliipphig "I" tfio t!lnvn>:if.igr(ipliic peaks. Builiiljlo jnocodnri'S have boon dnviwd to ovurmii.o this difficulty of itilei'fiiritig peaks. Oik* iiiHliiitl is to rflecL n hotter icsoluli<m of ihcso p ii iJ'-iilnr peaks by i lioin! of a suitubtu KUitinnary fili.iso (or CIA.*. Another innlhod, wliit'li nlro donums! latei. lliti proA-nco of theso cmnpoutidi in the sample, is llio lino of n pnilimiiiiny thin-liiyer chrctiuttuorupliio irenlniont'. The ck-sn.-dup extracts nra. oxmniiit'd mi silica gel clii-omiitoplMrs using A 1 per e-mil Kuloliiiii of unitmi) in lirynno ns mobile phato*. Spots corrc*ptjidhig to tho compounds cm llien be found at Hr values . between U S r.ml 1-C), whereas 1 tio t-mri- monly ocr mug org.vnec.Morine pesticide* ' mid their nivtuhnliirs produce spots of lower Hr values. A similar rep.-iml inn c.iu also bo . shown with remise phase paper chromato graphy* whereby r lx.- unknown compounds movu only a very short db-tunco flora tho linso line compared with the pesticides and their liv.iiihoiiles. 0's-iii|ui<l clunmatwgiapliy using dual ' clmhikI (I'lreiiuii sysicnv. with separate elc.ctroii-i-apliira nnd lliuiw-ioiiisuitimi detec tor;. has al.-o hocii used to deinoiistniln tho prMoace ef liirgouinviiiils of weakly electron- rupturing iiiaii'iiu), in addition to known pesliciil.i ii-ddiies, in l.hn eggs of oyster Catchers (fftiiiMiJopns Exiierieuci- in this i.ihnwiiory hits shown that iiic.su eompou(k- occur most frequently nnd in li'e iai 1'1-si. propori hm-s in (he livers, fat m,i! ei;,v,- of biicls, [i.irii.-iiliuly terr.>(riul prrvl.t'oic .-ii*h ns (.Irri/n'fcr riisi/s) nii'.! l..'*rcTs / I-V./sa nI'dih:.-,i : i id ntariii.; f, viler* em-h us gii'teniots [t<VVr Mid kiMnv.i !;;;< [Il.usa Iritf.iitylti); limy a!,.- coinmn,i!y oee-.tr in rie-hwiui-r fish. Vi'e have dvU->-(<-d rniull nmviint* in Jium.it) .'.i.il aniiii.il fnt sample?, hm loss frequently and in inmili sin.illir profioDimis Kir. 1. Gat-Ucivlil tiitleiitioii tins (cJn> nf (n> iMlrf.. I of Imtirt Uvtr uni iU a ri-iiuiifrrivJ pbrhli,nilii;ii.rn>l Kilo. than in iivi,;n rnmphs. "v A similar rcries or rhrmmitogrtiphie peaks has been properties. In tho proscribed extraction arid GI.C condi observed hy Jh'hU'ii1'''" when exnjiiining extracts of seals tions, thi'Mi iiii.Mtircs pioduceii series ef diion'adugrr.l'hle nnd fish token in Sri'lli.-h w.i:era. lit* found that the |)c,'j:s peaks of the Ij-p.* in quo.-tien. given hy i lie extracts nf fio.-.h nnil rca-wnler lisli rcpii-seie T).ni Ciiinpi'iiitals occ-iirrijig in I'litisli w ihllifc correspond li'd liui'ly l-.w eiv.e.-'.intnitiiins, hut thare given hyesimets >rseal l.'Iiihl'i'i' eiinesiii.lull'll In lillifll linger pnijiiiitions. ol'tlin nidi!)' fniinil l.y I hi.- I.il.iniliny in l.inls* eggs. Dili] tile e.is^ii( -ntI >(>i * >i inMly dIhiiiI I lie identity of llnw vnmpiiiii.itJill In 11/ * igi * *"s Inis In-cii lli.nkt in idem i lying them, Iml tilde ii.i-i hiti;' li-i'ii n gi'i.etiil Mipposiliott lliill ^to tlm nii ai- highly chWuiiited biphenyl c< impound; r.tt in'i "tlmiMlu- inoic hp'.Uy ehiiii'iifati'd ly]'""-, 'J`lvre highly chkii'inated hiphetiylr also occur to mhuc extent in the minlogims palycldorotoiplienyl pivp.u.itiiis which have coinmei.'iii! im\< eimilm to thoso of pol.'.'eld.OKihiphetiyl. It it pes.-ilde t hat renin nf the compound-- with very terg (litiy Wile eilln-r i'nrtiiri' h'l'iikdmi'ii fir condensation retention times fvriinitig in HrilisJi wildlife nro lightly products of tlin input.uetilmino pi`tieilh.!j>' or J'n.vihly c)i!oniuiti;d |io!yohlor(,i('ipiienylcomr.nmids. iooso e.en.p'iMiuU nf tin'so with natural products ruth ns protein iMMter. . Juncon. Iiouavvr, surai edcd in identifying a series of siieli jH'uks is torie-pniuliiig to p>tlvcl:hirntitpltcilyl com- patliids, in 2';,J pill" tnl.. n in ilitfen'iil j'aiIs of Sweden, l?ip. lo shows tlio yns-liqiiid (-Inoni itograiu of Hit ox tract from a kestrel liver. The jh'aks ef-rrespoiidiiig to pp'-PfiM (O' IS g), Is'la-Hllt' (H-33 iigl m.d g.Uilin.i liliL' (0*03 ugl .lie labelled. Tho other peak* form tho K-ii-.-* reforred to above and lira il now would have been rc-'i.rdt-d .And in an e.ipli)1-'. We li.ivn now been able to show Unit eimply ns "unkiion-n oig.inoelihuitic c-iaupomids not the long ndentiun time vompnimds (seurring in Krilish corn-prmdiiig to Any known jiesticidc or its nictaliuJiies". wildlife iii*,\ also pfilyehlfimhipln'iiyl compounds. Vig. 16 rliovo (hi, antilogous clihiiniitogrnm of a ci>inrrv>r- l'tilychl.ii'in'.ited liiph.-iiyl has h usu in cnumimi cmilifl'.'rcitil ii.-u for i.'inie limn as a i.'asticiwi' in pnint-s, iv.sins mid pliislies. Ti dlra has (livti ie.il insulaling prnperties mut can ho its-.! for a minds r i'f oilier pioti'Clivii puipesea. C'l.liliiieivi.il jv'i'parat lens of (ids rnaiiiiul aiv usually gr.'.dcil iirrnidilig lo (Ini rjegrn..' of eliloiinillifill, but nil of them an' s'lih-tniiriiiDy cetnnh^.- niis'lur.'-s >f polyelilomhiphenyl c...in)3'.iiimls tleU ('(mid Ik- exp -cled to iwruilA' theorg.u.ochinrine jvmicith'sin t beii chomiialnmlphysical ci.-il pcilyclilnrcil.iiphcry) l-.`ili. S' far us retenli.'.u time* ore cmiceriiid and apart from the |H)slicidc punks, there is okavI. jJinteJnng for nil but a few p'.iks in Uie iwo clirom,ito;:mms. . ' Tim chromutiiTciim* shown veni obtained hy use of a silicone gum (OlC-iSU 62) cohurni, hut. this pieoiso ur.r.-r- rpoiKlone., betwmi the retention tirn.sof tho pi..k for tho ii!.kt.oii)i compliant!; and tltuse fini.i tlio poivclilorn. hiplvcnyl ivsin It.is nlra Imeii dcinotistfiit. i! on 'Ajiie/dn f/ MON-MT-003221 ; ' K.l 'NAyuHZ. VOL. 216. OCIOSCR Z\T 1067 U'- 229 1. muotH'(sKrldktlislimutiitmLn.1T1i1mf...-( okxi uT-'iti.mfi,',r:iiMuikmii)imt 0Ml vOM'itxtl sltifoni f tt-SiiW . liitiimn Kl. yen flurlilrinw Wkf) t. 4'lllMlUH KUi i'Cll (tK~ XH CO mlitmti tl.K, M4 m1*91 l*7 2S1 an air-Mo 4-CH ftWra 7M9 Mi it.fc, Keitel V-.11 yr.r asn SOI ;> iiud ! M fr>it . <t'S7 0*55 l-Sil Sta'.'lti "7'C(1`7-" 300 4014 i'll fen, pulycHoioliifiti'tiji rain. v1*a2n1 8-ll U-BU . sr-iHJ BT4I 4-cn &ll In which (ley near u etrang nvcmWanra chemically r.iul physically. . Sumo of the samples ofliii'.l-iiviimimsl in this laboratory Itavti seemed in emitsin higher proportii'n* of pelychlern. biphenyl remjiiitmds than iirgamielilnriiie p:**t initios. l-Vr example, llu: pistils mi the ithromiitugntm for the lu^trel livor shown in Fig. I were estimated to Ih> equivalent to about 12 tig of |i*ilyelilnretii|ilti"iiyl comj'oitml*. This nuiHt bn emit ranted against tho org.meelilorim' po.-lici'ile residues lislnl itlntvo. Tli.t-e total only about (l-S i.R of which O'fiil ng is betn-HKC, mi isomer of BHC which is, generally rvgardwl ns non.toxic lo wildlife. Grout eortoern has often been expressed by conservation and cyanodliuorm columns. Tho net uni retention time* ists about tho effects of pesticides oil wildlife, particularly ivcorilcd Tor tlm {Wilis on theso throe type:) or column nro 'birds. Tlio identification of theso other orgaiiochlarinc givon in Table I. compounds in wildlife prompts enquiries ns to the poxaiblo Further toiifirmiiliou ns to tlm identify of these com* toxic effects they may behaving. That theso compounds pound* lias been. obtained by a study of their behaviour aro toxio is giuunully agreed,,,M; tho pelyctdorobi. on tliin-luvri' chi'omatnplmes, iihiirtiun unit silica gol phenyls are in fact. regarded as an industrial hazard and absorption ciilumns and reverse phase paper nhromato- threshold limits for them in oir have been advised**. grains. In mid ition. I luxe compounds !>avo been shown, We thank tho Xaturc Conservancy for samples of to rescmblu tlio polychioiobiplionyl compounds in their w.ldlifu and Monsanto Chemicals Ltd. for samples of chemical inertness. 'J'lni* i liny are not c.-wily modified by polychlorobijihenyl resin*. '' . simple rheniicnl reactions to pi educe readily idmtifiahlo shifts iti (lair retention *iun-s on GI.O ns c.in Im done", for Ecccivol October 3.1067. ' ins!ittieo, in p/i'-IJDT by hydrolysing it to p;>'-DDl or to * JIM,urn. J.. Atint>. 06, 407 (tt>>. aldrin by oxidizing it to dirldrin. A number of livers rtntl eggs taken from birds in the Britiih Mrs or lltvir co.einl waters Imvo boon oxn mined in this laboratory with results similar io those obtninod for the kestrel liver tvCrm-d tocnrlior. Wiilp lheldnntifica linn of tIn*4o rornpoumh; in British wildlife may solve the mysU-iv oT these peak* on Cf.O chroma leer,ims, it raise.;, however, tit,my other questions. Why. for example, tin them*r<mt|ioiiiiilitseem to bencctmmktied. most frequently nml in the Inrgi'st I'lvi-.riioii.*, in certain types or wild life Mirli .is birds, reals unit fish, and only tit the most in very si."."II pnijvu-l'oie it. man or his d.o.t- -lienuiimiissueh its cows or sheep T In litis rc-p-'ct limy room to lii.Vor marki.-liy I'reni the or{Minvl.{i<riiiu j*e.-li.'i.ws wltieli room tn have invad'd nearly nil aspect * of <nir environment uni! lUrrisnti.lt. Jl,, J. Sri. mi .<9rir.,17.IO(l!KO>. I /.Vjitrf tjHr (Ic'MMtnt C),w:ii, jo <11M Svaloticry Otlice. Loudon, 1063), ' Walker, II., Hamilton, O. A.,find H inisoa. E. II., J.StU /VJ .lint., W, WS *de Knulicrt Masst-icr, M. J., rjin, )f., Cn.li>', F,, Vi., nanauond, K. \V,, Kotsrii, J,, niri J., At.nl/tl, SO. Ida (1064). * Siialnoui, J. It., and 'Ltlci!, J. O'U., J. CSr4.ii*i!e*.-"i It. <1007), * Abbott, U. C.. >:;-n. II .,.unt Tli-injon, J., J. (Urniuf(V.,lG>4Sl <)00t). * Kvanr, II., Aiisly.'l, 37. Sf.t" 0!>&2>. * lirp'-rt of Hit CVirnr.iriii CSiimV, id7 (IIM Stationery O&m, LoitdoOi lt>66). " Hulilot, A. V.. snd Msradcn, K., J. Pik. Imt. Srir. Putif., 70S (luCO). " Hidden, A. V., .1. Ai'll. A'rvt..6.>:liOt..4S(IOS6). ' ' 6vi.-i.-n, 3., AV:r fr*\. SJ, CIS <;!>. II S-s. V, Irrii.r. /Mr,';-'--....* i'r-/ h.4*ntrial .trnlrria!^, !``1 <Rrtst-,|.l J*.:) 'W.liz . .rr.-,:.'.:!--!, 't-- VtV. tl"C.Si. * llri'wn,H. >1<Yiii(-.< 31. w f1047). i/ 'iknrhohl limit I'tVi, 41 (Cost-Tiittoc on Tlirciheld Liniil Vutirf, Quasi-ste!lar Sources, Superoovae and Novae by p r |,nu,,.r P, f. B.vOWNfc Uniyartiiy of Msrchmcr Instisuta of Science aru( Tccfcaofo^y 1 By considering the opacity of a surface layer of a star, the author concludes that <;uai-stiter sources, stipernovac and novae ivay be different manlfeitaiions of the same mechanism. * , It is usually considered Unit, the outbursts of novae and Mtpernuv.il. nr.> fuml.ittw'iit.iHy difibri-m procesai1*, but I shitll li.-iv jii-njiii'iit n m'-ihunirin which r.ni nccoimt- for both phi'iioiii.'im, imil u hich at I lie tame time eon necoutiv for ntlu'i' pi-ohlcm* <-.iuc.-mi.d with nu.'si-stclhtr sources ((Jiliisots). lit |iitrtii-u1.ir, I biigjicst tli.it tliuao outbursts nro liki-Iy lo ln> nniMiii.ijtie (ns indued f.l.r-y aro observed lo bo f.r iiiivno). Bi'C.ittse the ctM'igy K-loased during n Mipertnivn out hurst is camparatile with the ntullnr rest viu'iry. mi niiis-itmj'ic ombuist. cmld ruesn that the star i ci:..|er.itcd In rcl.uivisile vrlooily in nrdcr to cot*i-rvo momnit'im. thus nff.inling n Doppler explmintiun of tint twrsa red.shifts of lliejn-1 i-Mellav sunn'es. , Coituidi-r the opacity of a layer, J.. ut tlio snrfiu'u of a blur. J.et AW be tie- t!iieliiicrs mill J! I lie r.ni ins of J.. i.ml lot L rout.'iin pbiMiii, (. b nipoi.ituie. T. with t-b-r-iron mul po'hiMi inn ili,u-ili,,-i St mid .V ivsjicetivvly. /. will ,bi> upitq'ic lo riiiliiiiii.il of mtivi.|i.|i"(1i / prnviiUsl that 7 is ut*i;it ], where t is lie- up!ienl. (lf'|'ih of I.. A major con* Mil.uli.m to 1 is -.if. 1 be optic.,! thickness due tu ftw-frea absorptions. It. iskr.own that v//ec A/i (ref. 1), where iiid'icud nmisMons nro iuulvidcd. Siippnsv. now, tlm;. Tj is coiupii-sscd or diluted without changing the total minibus of ions; that is. All is varied under om.ilii ions which maintain constuiil tr/{sAlfA',. so that, Ah'.V,-- constant. Evidently vy/Ab.ViA/.' u.ViClThus compression of L increasei its opacity, while ilitniion vdiieei tlm opacity, ' Of iooitvse, tbo totnl mimljer of ion* will nut remain, constant in practice, hi'cauto the recoinbiiaition rate i* pro;wrl inn.it fn S,So -If tie' percent.igii of alums inni/cd liirgi'. tlio density of unuviiiuvl ntoms. A', will il.ereforo bo proportioiiid to A'..V|. Tht* nvnns tlutl tie- c.iutrlm- lion to lhr. opacity niado by boimd.l.otuid oud b.-ui.il-fieo trmisithuih wiiliin ui.iiuiizi'il p.tc>uis is also pr.>pai.'i,,n:il to AbA'iA/f. This uff'ct, recngniziil to bo iiuj-.n^.iit- for slcll.tr pulsation'.*, further increases the ppuetty nf l, on compression. . Som consequuifCM of (his variable surface opacity will notv bo cxnmiited. I'jatcr equiiibritun couditieiis tho * MON-MT-003222 TOWOLDMONOOQ3246