()nder,;tepoOI"f ./ou?'nal of l'eterinary Science and Animal Industry, l'olume PJ, _;\'umber 1, lul:y, 1939.
l'rintNl in the ('nion of ~onth Afric:a by the Governm<.lnt l1riater. PrLtorla.
The Cystine Content of Merino Wool in Relation to its Physical Attrib utes.
By S. D. HUSSOUv\T an<l Y. BOS~fAK, Section of \Yool Research, Onderstepoort.
ll\TRmH:CTlOl\.
THE t:ystine content of ~Ierino \Yool is appl'O-"imatel~- 12 per cent. and although seYeral resear('h 11·orkers haYe studied the source and formation of this eonstitueut, the function of <·ystine in )lerino \\·ool production hom nutritional aud physiolog-ical aspects has not :vet been defined. In the present contribution it is not intended to deal with this aspect of the problem but to discuss the results mainly with reganl to the relationships between the physical attributes of wool and its cystine coutent. These ph~·si('al attributes largely determine the uses to 11·hich ~Ierino \Yool may be pnt and are valuable assets either during· the processes of wool mannfacture or in the fiuishe<l fabrit:. Should the <oystine content of Merino wool be a moclih ing fador in its physic.al attributes, quantitatiYe variations in cystine would h:we important applications in rnethods of wool production.
In t h<:> pre;;en t im·estiga tion a series of selected )ferino wool Rnmples 1Yhich differ from one another in their physical attributes has been anal~·,;ecl. The c~·stine conte.nt is eompared with such chmacteristics as 'fensile Strength, Fibre Hesilience, Fibre Fin<>- ness, Crimping·, Sealines,;, Percentage Ext<:>nsion and Whiteness.
Jh :YIE\Y 01-· LrrElL\TT;m·:.
Fe"-figures are aYaih ble on the correlations beh,·een the cystine content of Merino "·ool and its physical attributes. Several workers have analysed "·ool fm snlphnr content instead of cystine, but since it has Leen shown b:-· Rimington (1929) and later by Barritt (1934) who allo\\·ed for the methionine content, that the sulphur content of wool can be converted into cystine, tlw r<>leYant work dealing with the sulphur content of wool has a direct bearing on the present con- tribution.
237
CYSTIKE CON'.I'I-:.\T OF 11ELU:\"O 1\'00L.
Barker (IU2!J) iu dis\'ussing the ide;~l bhri!' and thl' JJJamtl'ac- turing· properties of \YOc>l ;tswderl " that for an extensive seri.,·s of wools of difh•renl type:; lilerl' i:; a sigJtiti<;ant variation in '3UL!lhu;' content, "·hid1 i:; unrlo1thtetlly <·aused by biological, enYironn:e11Ld and other inHuen\'es, aJHI 11·ilich illlparls to the fihre considcrahL~
Ya ria! ion.~ in i b responsP to textile JHO\'f'SSPs ". .r\. fter discuss in;~·
tlte Yariati011s in the ,;ulpliur r·ontPnt of clifierent \nJOls B,uker goes on to say that " it j,; signific;>nl th;tt hig·h sulphur \'Onlent is ;~crotn
panit·d h~· a lo11·er rPgain of IYool and it is ceri<tin tlwt breP<l, en- Yironmenl and pnthologi!';d <;Ondition of the nnimal play p1·olllinenL parts iu its deYPlopmenl ''. ,·\lso " ' ' high ,;ulphur conlt'iil is desintble :m<l it "·oultl sePm 1o be the first clifnt·nlt.'· in tlw pwdud ion of 011r i<lt•al f.Jln·i(' a,; lo ho11· to ohlnin it ".
:-;[dey (lD:\1.) ;tn;th·st•d l11·o •·l::ts . .;es of \ t'\1. Ze;~l:tnd \Yoob for sulphur, the one lot h.eing <IPsign::ttPd hy UtP tr;~de ;ts <1 good pro- cessing· 11·ool ;tntl the othPr a fair pro<·Ps . .;ing loL lfe fmtnd <Ill itJ.'i.!.!·- nitic;~nt diften•nt'<' beh1·eC'n till' h1·o s<·ls in tl1Pir ,;ulphur coniPnl.
Honsnw ;JtHl .Jotti:<>d (1'):\-1.) 1101·kin!.!· on '\rNino ~l1epp found ;111 insig-tJifi\'an(· <·OITPlation of (1·:)12 lwl11·een tlw sulphm· content and fi.hre fine11e:;s antl then~ <IJ>JlP<IrPll to he no correlation hPt'>~·Pen sulphur
<;ontf'ttf. and ·· qualit.Y " in \lerinu 11·ool, a11art front 1lw f:t..t that lll<•<lulbte.J fibres are inclinP<1 to lw lo11· in sulphur.
Y<tu \\'yk, Hotha and Ht·kl\Yl' (HJ:):)). \Yhile studying th<• efl't'<·l of suppletnenh of different iorllls of sulphur in t·he diet of ~Ierino sheep, founcl I hat, "·heu lite animal,; ,,·ere dosed :;;u!'h supplemPnts as cystine, sulph;~tes, E.CSS and S, !herP "·;1s 110 response in their scourC'<l fleece 11·eig-hb, me;m tihrP leng-th~, filne I hirknPs~ and Jll<•::tn fibre \\·eig-hts of shoul<ler san1ples. Subsequent 11·ork b;;· Bot ha (unpuhlisltt>cl) on the c~·stiJI<' content of the experinwntal \Yools showe<l 110 rorrelations h.:•h,·pen tl1P gnntps. so tl1;d· the ;dJo\·e- mentione<l physical attri hut es llid n ol appear to l>e rone la te<l w itb thP cystine rontent of thl' \\·oob.
Sntith and Harris (l!):l(j) o::.:i<lisecl 11·ool nrlifi<·i;tll,\ ,,·jth hy<lrogPn JWro:-.:ide and ;ts a result Ill<> <·.1·sLine thopped front II·() In ,'-;·.J. pPr t·(•nL 'l'hPv ;dso fountl that " thP oxi<lal.ion alone shmn'd 110 sig·ni- fi<·anl eff<'r·t on the :wl]iltur <·oJdenl, ,,·~:·1 l>rPakillg- ,;tn·ng-111, an<l re,; ilit•tH·.\' of the ,,·ool '·.
S11·arl (l~J:Hi) 11·hpn f<·Pding sulphur lo :Jierino ~h<·Pp fou11d that altlwug-h I liP sulphur •·otil<··nt. of }l,·rino wool 11·as a ,.~ll'i;thll' cpt;lnlil.Y.
no relation;;hips t·onld lw e:;;lablishe(l l>et>~·eell sulphur rontent and staple leng·th, diruneter of tihrP. e:den~ihilily, or nintp~ p<'r in!'h .
.Jic.Jiahon and Speakman (1937) \lorking- on ~e11· ZPabnd Romn<'y ,,·ool, found tlifferenr·ps hebYt·en the tip~ an(l roots of fibre~
in so far as tlwir sulphur contents ,,·en> concerued. 'l'hPy also foun<l differen<·Ps beh1·een thf' tip . .; and roob of fihres in their 1 PlatiYe degTPPS of "st't" Their figures for Y::triation in the sulphur couteut \YhPn conYerle<l into cydine content rang<> hom 11·8 to 12·() per cent.
a11tl ::tg-ree with tho.~e found in the pre,;pnt 11·ork.
~-'lR
S. ]J. lWSSOl1\\. Ai\'.1) V. HOSlliAN.
}1ETHODS.
Cystine 11 as delt'Imined by the modified SnlliYan meihod of Rossou"· aud \Vilken-.Tonlen (1934). Approximately 1 gram of de- g-reased and IYell-IYaAhed "·ool \Yas freed of Yegetable matte1· and sand by handpicking untler distilled IYuter with fmceps in ct large tlish. The wo-ol was collected on a G2 ,) en a ±ri t.tetl glass fiHer w hie h 11·as dried by suction ancl conditioned in the Constant Humitlity chamber until constant ''eights \Yere reached. 'l'he IYools were then clissol veol in ten tiu1es their weights of G N,HCl and placed in a controlled autoclave at 145° for
a
hours. It was shmnl that this was sufficient time for complete hydrolysis without npparent loss of eystine. The hyclroly:sate IYaSn
ltere<l through G0 .Ten a hittetl gln~,; filter~.washed and maJe up to :snitable volnme SU('h that .j ml. of the solu- tion should provide approximately ·4 mg. of cystiut>. The colmi- metrie determination IYa,; earried out in the Consbnt HnmiclitY Chamber at a coustan t temperature of 70° F. (It has been sho"-;l that a constant temperature is necessary in the colour rleYelopment.) The cystine is expressed as a percentage of the clean rlr:--wool.
In each t.:ase an aYe1ag-e of tlnee readings was iaken ±or the sample, which system proYed to he a. reliable mH:. It \YHR also sho1n1 statistically that there was a greater Yariation lJehYeeu groups con- stituting the average than there was IYithin the groups, so that a 1·enl difference exists aTuong }Ierino \Yools in their e:;-stine contents.
Physil'al Att?·ilndes.
These 11·ere detenniued in the Coustmtt H umidi tv Chamber at 70 per cent. TielatiYe Humidity and 70° F. The metho~ls employerl antl a ppara t ns used at 0 nderstepoort ha Ye a lren rl,v he en cl esr-rilw<l (Bosman 1988) thert)fore only an outline of the methods userl in thici
\York are given here.
The tensile ~trength anrl pereentage fibre extension we1·e rleter- mined on the Doehner apparatus and the methorl~ of sampling the wools usPtl in the study are those described by Boc.;man, \Yaterston antl van vVyk (Hl39).
'l'he Fibre Hesilience, t>xpresserl as tht• energy necessary to com- press 5 grams of clean wool by 50 per cent. was determined by the Pend ultex Apparatus devised b.v Henning. A detailed method of analysis is tlest:ribecl hy Yan \Vyk (Hl39).
Fibre Fineness \Yas detennined on a Zeiss Lu nameter. Th"
crimping was measured as number of crimps per inch. Senlint>ss ''"' t]p(·ermined h:v :l l l apparatus designer1 after Speakma11, the tedmiqur' of sampling, monuting of slitle.-; a11d inte1pretati.on of .reatling-;:; being·
that described by Bosman and Yan ·\Vyk (1989).
The degree of "·hiteness expresRecl as a pereentage of standarrl white, 1nts detPrminecl by the apparatus rlesig·IJed by IIe11ning, where
23 239
CYSTINE CONTE:\T OJ:' ~IERIXO II'OOL
the white light is determined by the cunen( set up in ;1 pholo-eleci.ric cell, care bt>ing (;1ken that all thP ~amplPs "\YPrc clt•all~Pd of inq)llrities by a standanlise<l method.
J•:xPEin~IF.XT.\L R~-:sn:r<;.
l'he results of the <lnahsP~ are suntmarise<l in Table 1, 11-ll!.'l'r it is shown thai. the c)·stine co;dent nries from 10·8(i to 12·1:) per cent.
with a mean of 12·02 ;~nd ;1 t·oefhl'i<>nt of Y;niahilil_\· of:{-!) pPr t·pnf.
This Y:niation is t·omp;n;ttiYPl,l· ~m;;ll 11·heu it i~ t·omp;trt>cl 11·ith lh;d of the tensile strength ("i·.S JH'r c<'nt.) or DPsiliPtll·c \22·;) pt>r CPtd.) or the FibrP FinPnes;; (11·0 pe1· c·Pnt.) or Crimps pel' inl'h (12·!) JlPl' c<>nt.) or sl'nlinE'~~ (l(i·(i JWr t·Pnl.) o1· p:dt•n.;ion ;li hrt'<lk (J:{-(j JH'I' cenL) or \Yltilen<>ss (G·.S per t·t•nt.). Jl must·. ihen•f'on·, he l'Onclutlp(!
that· ilw cYstiuP I'On(enl of :Jierino ,,·ool Y<tl'ie.; le"' th;ln clo thf' ph_,·sic:al t·l~;tmci<>rislil's emltlll'ratl'd.
T.IIIIJ·: 1.
The Cystine ('onlent of .1/erino lTool iu l?rfotion to C'crtoin o.f its l'f,.l;-'il'fll .I Uril111tn.
·1i.
~:).
:n.
~1.
-IH.
(j~ .. lJ I. 1:20.
~!).
1-1.
;)J . . . .. ... . 4:>.
4(\.
~II.
:!:2.
:3:!. i I.
.) .
!I -1,(1
;~;;.
:~G.
:!.i. 10.
l!l.
:'IIC':tlls .... . S.D ...... . Cocff. of Y .. .
TenHile Cy~tine ~trength ('ontC'nt. Gm'
Per C0nt. 111·86 12·5:!.
II· 8i I I · ;) 1 I I · i4
I~ 08 II. :!.3 II· ~4
I~ :10
I:!.· -1 i II· s:{
II ·83 1:! 60 I I · 1:3 11-:n : l·!lO I~ ~0 l:l·/;j I:!. .;.;
I:!. -1.) I J · !li l l ·Hli 1:! -II ll·!).)
1:!. -1:)
1:!. 0~
·46i 3·!l%
1 ('C'xiO"
I) KK
i ·l!l
I . ~:!
I · ~ :l 0 !IH J .·)·) l· :!.~
1 ·O!l I ·OH 1·:\!1 II !)II
I· IH 1·1:!.
1-:n l·:l:! l<l!) I · II 1 ·1:1 I ·-li
·Il-l .. IJ
·.):!
.. )!
·-IH 1·-H
Hesili-
011('('
·!1!1 .; .
,, - ,
:3 :)I
·) !,7 :2 ~t~
:{. i!)
~. i!) :1· -1 i -1 !i(l .'i Iii
:l (i ~ :~ .-)~
·1·111 :) 11!1
;) fl(i -1 :JH :l li>
:)·l(i :~ liH
.) .-)1) :~ ,){j :{. 411 -1 llli :{ 88 :l s.;
:{ .)II
·781 :22. ;)o o
Fibre FinC'·
IH'~S
(/").
I i · (l:!
:!.:!·!.) :!:! ()!)
:! 1 · :n
1!1 !ill :!.<i o:;
IS· l >
·)·}. n:?
;!.i !J-1
17-~K I !I i.i
~(1 :!() :!!·:!.!) :! I· 7.j.
IS l i
~-~ .)() 18 ;)(i :!II (i8 :!.II·.)!)
:!i ·8J
:,?(1· 7:!
:!-1· /.)
;!(I .)() I!J ():!.
:!l·l-1
·> ±O!J 11. (10 0
Crin>J>-
Ill,!!
Jll'l' ill<·h.
Ill II 13-1~
!O-Il ill II I :3 1-1 Ill II 1:!.-I:J Il-l:!
Ill II
!.)-Iii
!) Ill 0 Ill 1:! !:J l:!.-1:) 14-1:) ]:!
D-10 H i(l Ill 1:!
iJ-1:!
1±-J.)
!!·(iii j ·-1!1!) 1:2 !)00
Sl'ali-
)}(':-::--:..
J•('f' ('('lit.
/li·7 -1.) -1 (ii. () i!l ·I Iii () 7:~ 8 fi.) -1 lil·li .):! .) .).) -!-
lii·!l Hti ·>
H:!. fi (l.).
li.i :) (iS ., IS -1 HI !I
(il·-1 -11·7 (i:J (i II (i
(i7 ·!) 1 i . :!-1:!.
Hi. 6° 0
l·:xten- . ..;rnn.
1'('1' ( 'l'llt.
IK :!.) Iii ·47 li!I·IO li!l (1,)
IX ;)S
~.;:) ·fill
.)! . :):!
.lH ~:~
i'\11 ():!.
.-,:! X.J H!l .J.:) 7:! H:l H:l :l:J nq-7H (i7 (17 /:l ·II (i.i () 07. 7;)
.-,lj \1:!
HK .J-:i n.-,. I :l (i.) 7:!.
7:!. 8:~
li:l 68 (ii. i.)
!i!l·lS
\J·.J.:!.H 1:3·6°~
\\'hitP·
ll('S:-i,
Pvr
('('Jlt.
.-.1 .-;
,).1· 7 .i!J I
.-,(i :J ,)(; :J
.)!). () .)X ·' .):! . ().-, 7 .;.-, li :;:J :J .):! . !) .)X ·' .)-!·.) :;:l ·I (il·l .)-1. I :)H (J .)!1· I -18· .)7 . .!
.)7 () .)!1· I (j;! 4 6:? -1
.-),
~;{. !J(I(j G·Soo
S. ]). H.OSSOU\V AXJJ V. I!OS".\U.:\.
A comparison of the coefficients of eorrelation between cystine and the physical attributes cn·e g-i.ven in 'l'ahle 2.
TABLE 2.
Shon--in.c; Coe.fjirient of CorTelotion (r).
I Tensile
I
H.esili- IFibre
Crimp- Fine-
Strength. enre. mg.
ness.
Cystine. ... ·1714 ·4509 ·2181 ·3281
llegrce' of Preedom .. :23 23 22 :20 - - -- -- - -
According to Fisher's Table of 1·:-
IYhen P= ·05 and \Yheu n=23 iheu /"'= ·3951
" n=20 then r~ ·4227
I
Scali-I
Exten- White- ness. sion. ness.
I
·2242 ·070ii ·1026
:20 23
when P= ·01
·4999
·5368
23
'l'he only sig-nificant con-elation (at P=~ ·Oii) is that hetwee11 cy::;tine and resilience with a Yalue of · 4509. The ch:uacteristics of ieusile strength, Fi.bre Fineness, Crimping-, Sr·alines:>, Extension and
·whiteness bea1· uo 1lefinite relationships to the cystine eonteni.
SL'".\DlAitY .IC\JJ l'o.:-;cLUSilr:-<.-; .
.A series uf selede1l .JleriHo 1\"lJul samples that differ lllarkedl~- iu their physical attributes "·ere anal_ysed for cystinl'.
The recmHs sho1Y no sig-ni:Rcnnt co1Tehti1ms hetween il1e cyslinP l"OHtent and 'l'ell~i.le Stre11g·th, Filn-e Fi11enes,;, Crilllping, Scalilll:'ss, Percenl<lg-e Exiensioll or \Yhiteuess. This iii contrary i.o the fi.l1C1in~s
of certain other workers.
There is a certain ,;ig·nificaut cont>Ldion (at a --1 IJPl" cent. lcYel)
hehn~en cystine content a11<l resilience. 'l'lte Yal ue o.f this conelatioJl is, hoiH'Yer, not high.
It is COllClllded that tlu• role of C)·,;tine in 1\"00J. production i,; 110t an important one, an<l that ihe possihilit~- of illlpioYing- IYOol charal:- teristics Yi.a the cystine content does 11ot appear to be great.
ll.-\ I{ lUT'l'. J. (1D34,). 'I' he distribution ~lid orig;in of w lphur in 11·ool.
r. M:f'thionine in wool. Jiiocliew. J .. Vol. 28. pp. 1.-;)_
130'\FDf.-\. F. N .. A:<D JOl.JBERT, .P. J. (1934). 'l.'he sulphur !"Ontent of merino 11·ool: Tts distribution and relation to fineness an1l lJllalit?. S.A . .l .81' ..
Vol. 31, pp. 3<17-370.
BOS:\IAX. Y. (1918). Progress in the methods of IHJol research. Fannina in South .<1/nm. October. HrlS.
241
HOS~i :\::\. V .. \\'.\TI~I{SO::\. 1•:. A.
till r lw Tc•Jisi IP Stn·ngtlt of Pn·paral ion).
.1s D \'.-\::\ \Y YK. U. :\[. (19.39). Stml ics South African .\Jt•riuo \Yool (1\.cport m
llO:·DL\::\. V., ASD \'.\::\ \\,'\'1{. (' . .\1. (1939). Studi0s on the Scaliness of South .-\fric·an '\it>rin" \\'ool (ilcport in !'reparation).
~lc.\1..\1-1.0:\. 1'. H . . -I:>CI> Sl'l·:.\1\:'\l.\:\ . . J. ll. (1~137). " TIH• .\dion of Light or~
\\'ool. ·· L. Tlw titr:ttioll crtrH's of intact a11d t•xposed 11·ools. 1'run.o.
For. 8tw. \'ol. :n. p. 84-1.
lll.\U:\GTO::\. ('_ (19:2\l). Tlw rc•l:>ti<llt lwt11·c·elt t'\'.stint• ,-ir•lcl ancl total sttlphttr in 11·ool. ]iiocli'·"'· ./. \'"1. :Z:L pp. -11--Hi. · ·
HOSSOl'\\'. S. J) 1:-cD \YrLKr::\-JOI{Tll•:\'. T. J. (193-1). Stndies on the origin of tl1<· <sttlph11r in 11·ool. I . .-\ stud-'· of ilw Srrlli1·;1n tr•<·hniqt;e for r·\·stitH'. Ot~tlen.II'Li'"'rf .fuUttllli. \'"'- :2 . . \ o. I. pp. :](il-:l(;~.
Sllli~Y. J)_ J. (1\l:lli. Tilt• St~lph~11," t'lllli<'lll of soltlt' ~c·11· Zc•;d;rncl ,,·ook ./.
'!'e.d . /11.<f. \'ui. :2:2. 'j' .l,()-.l,.,_
S" 1'1'11 . . \. _,_,u 11:\I{I{IS. ~i. (l!;:)(j) Tltc· o'-Oidatioll of \\'Old. Til<• <·ffer-t of hl'(lrog;t•JI JWro'<itk. .lm. l!'i''·'· i:euf. \'ol. :2-i, pp. ]1'0-11<:2 .
.
S\\'.-\ 1{'1' . .T. ('_ ( J!):JCii. Tilt' illflttl'll\'(' of srtlphttr in ;1 ration on the gro11·th
<lrHI properti<·s 11f ll'ool. 5/,eil->clt. f. 5/,ii,-/tfu"'l- I{Piill' B, 13d. :{(i. h. :J.
pp. :107-:]:l(i_
\'.\:\ \\'Yh:. (' ~~- JJO'I'II.\ . .\1. 1 •. . I'CIJ 111':1\1\:EI{. J. G. (.1\):J:)). Till· dl't-d of -" tpplt-lltt'llls ol· dilfcn·rtt forms of sttlphttr to till' di<·L ttpon ilrC' \\'OOI of 111\'rillo slrct·p. Ont!,•rsfvf)l!<u·l }ullr!llli. \'ol. .). ::\o. ] . pp. 117-188.
\'.-\:\' \\'YI\. ('_ ~i. (1D:l9). Sllldit•s on t!w He.silien<"<' of 8o11tb .-\l'ri<"an :\lerino
\\'ool. l~t'port ill Pr,•p;uation.
242
