Document 7MjY5879aoNkzXG1m4Gm49bK6

Effect* of a Polychlorinated Biphenyl and a Polychlorinated Oibenzofuran on Molting of the Fiddler Crab, Uca pugllator Sue W Fingtrmen end Milton Fingetmsn Oapsrtmsnf ot Biology ru/ono Univtritty Now Otl*n, la. 701 IB Several species of aquatic crustaceans hava been found to eccuaulate polychlorinated biphenyls (KBs) from their environ ment. Specifically, VWM at al. (1971b) shoved that tha flddi.tr crab, gca MllUtot, accumulates tha Kb, Aroeler 1254, fro* eontamlnate3 iMiawli. Bovtvar, chart ara no published raporta on tha paaalbla affacta of PCBa on tha physiology of tha fiddler erab. tfe undertook a atrlta of experiments to determine the ef fect of the KB* Aroclor 1242, on tha rata of molting of tha fiddler erab, Uca pugllator. Fairly recently, however, poly chlorinated dtbensolurane (KDfs) hava not only bean shown to ba Impurities in Kbs, but aleo to exceed the toxlelty of KBs in ehiek embryo aeaays by approximately four to six orders of magni tude (VOS at al., 1970; BONIS at al., 197Sa,b). Consequently, reported affects of KBs, as In mortality studies such as that of SUMO et al. (1971a) with tha pink shrimp, Panacua luontva. may hava bean due in large meaeure to contaminating KDFs. therefore, in tha preeent Invaatlgation axparlmanta vara alao performed to dataamina the affect of a PCDT on tha rata of molting, the KDP csncantratlon used being that found in Aroclore by BOWKS at al. (1973b) Ufa of uch a KOF concentration would allow ua to de termine whether any effecte on molting ware due to Aroclor 1242 or to perhapa only KOF contamination of the Aroclor. Materials and Methods female fiddler crabs, tfca pugllator. from Panacea, FL, vara mead. Ihe arabs vara lotermolt iMlvlduale, having a carapace width 14-14 nm, and ware intact at tha outsat. They ware kept throughout eaoh experiment In Individual styrofoam cups with translueont covers at 24C under constant llltainatlon. Iha light intensity inside the covered cups vaa 374 lux. Tha erabs were fed uncooked oetmeal twice weekly end tha madlua in which they were kept was changed twice weekly, after they had bean allowed to feed for approximately four hours. The fluid level In the individual containers was about 15 am deep. The crabs were induced to undergo ecdysls in two wayst (1) by rMoving both eyestalks (MOW!* and cinmDfQMM, 1939) and (2) by remov ing four walking lags (HUNT, 1905; SXimSt and GRAHAM, 1972; * riBONMAII end PWOOMAIt, 1974). Xheae methods to induce molting l.w activity ware in the labored HAS, 1974, 1974 crab to auteurpinched . Tha data as tha ctmulet' acdysfs since ti ware calculate* crabs that her that had undetg yet undergone by 100. Cach * tha two experim tha figure* pra Ti.* Kb c (Monsanto lot r ch1orodibansai -. stances ware fl to the deeirert Ocean, Aquarius (ration was | X final OCDF eon* was usad beceus concentration B they tested. : containing tha taining the KB Iha ob)pand repeated haffect of Arocl crab. In each used. from ea*. right side ware containing Al served as contr msmbats of th tha Aroclor at The eyeet lng laga that rata (Figure , underwent eedys control groups Aroclor undetueuraa l and 2, f The objs whether tha in 1242 (Figure U inant. Conseqv stalklcss crab* MONS 003236 ctivlty were used because the rate of ecdysls of Intact crab* in the laboratory la ordinarily vary Vw# (FINCERMAX and FINGER- HAN, 1974, 1979). Limb rmaoval was accomplished by inducing tha crab to autotemlse tha limb whan tha mtrus of tha limb vaa pinched. Tha data (ro tha axparlmanta dascribad balow at* praaantad aa the cumulative percentage# of the craba that had undergone eedyal# alnca tha atart of the experiment. These percentage# were calculated day by day by dividing the cumulative number of crab# that had undergone aedyei# by the total rnaaber of crabe that had undergone tedyaia plua tha number alive that had not yet undergone eedyal*, and then multiplying the reaultlng retlo by 100. Sech experiment wee performed twice. Averaged data from the two experiment! of each eat were uaed in the preparation of Che flguree presented below. The PCS choean for uae In these experiment# wee Aroclor 1262 (Monsanto Lot Number 30016); the KOP wee 1,2,3,4,5,6,7,6-oeta- chlorodlbenaofuren (OCDF) (AnaLabs Lot (Amber 001). goth aub- taneea were first dissolved In acetone and ultimately diluted to tha desired concentration In artificial sea water (instant Ocean, Aquarium Systems, Inc.). The final Aroclor 1242 conean tra t Ion waa g X 10**% In sea water containing 0.1% acetone. The final OCDF concentration waa 16 X 10'This OCDF concentration wai used because 2 ug FCDF per gram of PCB was tha hlghaat FCDF___ concentration BOWIS at el. (1975) found in eny~of the Aroelors- they tested. The control crabs warn kept in artificial aee water containing tha same acetone concentration as in tha sea water con taining the KB and OCDF. . Experiments and Results The object of the first experiment, started July 22, 1975, and repeated beginning September 17, 1975, was to determine the effect of Aroclor 1242 on the rate of ecdysls of tha fiddler crab. In each experiment four groups of 50 crabs each ware ueed. From each crab In one group the four walking legs on its right side were removed, these crabs were then placed into cups containing Aroclor 1242. A comparable group lacking four lege served as controls. Both ayastalks vara than removed from tha members of the two rmaming groups, one then being exposed to tha Aroclor and tha other serving as tha control. Tha eyestalklete control crab# and those lacking four walk ing leg# that served as control# underwent ecdysls at # rapid rata (Figure l). However, the group# that ware in the Aroclor underwent eedyal# at a much sInter rets then did the respective control group*. In feet, none of the eyestalklee* crab# in the Aroclor underwent eedyal# during either experiment, in both Fig'wrea l and 2, bay 0 represent# the day tha experiment was started. The object of the next eat of experiment# was to determine whether tha decreased rata of ecdysls of tha crab# kept in Aroclor 1242 (Figure l) my have been due In any degree to a FCDF contam inant. Consequently, craba lacking four walking lag# and eyetalkie## crab# ware exposed to OCDF instead of Aroclor 1242 and )3P M0NS 0O3231 751 TIME IN DAYS Figure 1. Effect of Aroclor 1242 on tho rate of eedyele of eh* fiddler crab, Uca ouallator. lapty elr<l, crab* lacking fouj walking lag* in Aroclor i2i2; filled circle*, control craba lack ing four walking lags; clrclee half-filled on right, eyeetalkleee czabe In Aroclor 1242; elreloa halt-filled on lefe, eyeeealkleea control crake. J40 50h Co tf) u<ni 5 a 25 I I Figure 2. EH< on the rate of lege in OCDf; t lege; sire lee >circle* halt-fi HONS 003238 TIME IN DAYS Figure 2. Effect of l,2,3,4,S,6,7,goctachlorodlbnsofurn (OCDF) on the rot* of aedyai*. Knptjr circles, crabs lacking four walking tag* In OCDF; filled circle*, control crabs lacking four walking lag*; circles half-filled on right, eyesealkles* craba in OCDF; e ire la* half-filled on left, ayoatalklaa* control crab*. 141 MQNS 003239 the incidence of ecdysls we* determined (Figure 2). The two Identical experiments of thil lot were started July 8, 1976. The control crebs lacking eyeseelka or four welkins legs under went ecdysls at races only slightly (raster chan those of che corresponding groups in the OCDF, the difference between the experimental and control groups being somewhat larger In the case of the eyescelkless crebe then with the erebs lacking four walking legs. Discussion i ---- Aroclor L242 drastically inhibits the rets of molting of fiddler crabs lacking cither both eyestalks or four walking legs (Figure 1). in face, Aroclor 1242 completely inhibited eedysis among the eyestelkless crebe. However, the OCDF produced only a relatively slight inhibition of the rate of molting (Figure 2). It is, therefore, highly likely that only a very email proportion of the inhibition caused by Aroclor 1242 would have been due to PCDF contaminants. Whereas by tha end of the experiments with the Aroclor, the ratio of the percent eedyaLa of the eyestelkless erebs in ths Aroclor to that of the control crebe wee 0.00 end the corresponding ratio foe the crebe lacking four walking lego wea 0.21, the rstloa derived from the OCDF experiments ware 0.77----- for the eyestalkless erebs and 0.89 for the crabs lacking four walking lege. Therefore, although on en equal weight basis, PCDFa appear to be much siore toxle to chicks then ere KBs (VOS et si., 1970), the vest proportion of the inhibition of molting activity in the fiddler crab produced by Aroclor 1242 appears due to the KB itself and not to tha small quantity of PCDFs that are contaminants in Aroclore. Acknowledgement This lnvesttgstion was supported In pert by U5PHS Grant Humber 5-SDS-RR07040-08. References BOWES, C.W., MULVIHILl, M.J.,DECAMP, M.R., end A.S. KENDE. J. Agrle. food Cham. 23, 1222 (1973a). BOWES, G.W., MUIVIH1LL, M.J., 8M97NEIT, B.R.T., BURLINGAME, A.L., end R.W. RISEBROUGH. Nature 2^6, 305 (1975b). BROWN, F.A., Jr. and O. CUNNINGHAM. Biol. Bull. 77, 104 (1939). FINOEBMAN, M- and S.V. FINCERMAK. Eool Jb. Physiol. 78, 301 . (1974). FINCUtMAN, 8.W. and M. FXNGERMAJV. Her. glol. in press. HOMO, D.B., BLACKMAN, R.R., WILSON, A.J., Jr., and J. FORESTER. Mar. Biol. U, 191 (1971a). NDtfO, D.R., WILSON, P.P., BLACKMAN, R.R., and A.J. WILSON, Jr. Nature 231, 50 (1971b). WINNER, O.M. end 0.1. GRAHAM. Eiol. Bull. U3, 222 (1972) a VOS, J.O., K0IMAN, J.M., VAN ORE NAAS, H.L., TEN N0EVIR D8 BRAUN, M.C., and R.H. DC VOS. Pood Cosmet. Toxicol. 8, 425 (1970). ZILXNY, C- J. Bxp. Zool. J, 1 (1905). ~ M2 Acuta Eftacts c Methyl aarcu end although marc established, the fish organs (e.g. 1973). Fishes et asreury in huaea tlene corresponds (BBRGUJHQ 21 ik* According ec relatively high c region# of Worth Kleeleolppl coate Mercury residues curie salts (D'lt chloride wee need It has been fish eight serve neaely aatbyl ear dehydrogenase, ec end kidney have t toxicity (KXKAU ly daaaged by L0t The purpose tlel toxic effect dosage of on erg* sloes it Hoe been In tha atthyiatod Pith Channel cat! obtained free e 4 110 gallon glean well aerated end vote allowed to fc three aontho tftr Methyl aerev I. it, N. I a iwr Sr *!"" HONS 003i*Q