the ‘brown spots’ (bsp) character ofdrosophila melanogaster and its relation to copulation

3
360 Br6ves communications - Kurze Mitteilungen EXPERIENTIA XlX[7 cerebrospinal fluid) were carried through the entire pro- cedure in every experiment. This is important, not only for the calculation of the recovery, but also for the quali- tative determination, because the presence of organic material usually causes small changes in the Rf-values. By this method spots have been observed corresponding in position and colour to HVA and VMA added to cerebro- spinal fluid. The amounts of the acids were estimated semiquantitatively on the chromatograms. The recoveries of HVA and VMA were about 40%. After correction for this, the normal concentration of HVA in cerebrospinal fluid was estimated to about 75 ng/ml and of VMA to about 25 ng/ml. DOPAC and DOMA were not found on the chromatograms. Nor was it possible to detect them spectrophotofluorimetrieally after condensation with ethylenediamine 3. The recoveries of added DOPAC and DOMA varied between 50 and 60%. The catecholamines in the central nervous system have two inactivating pathways. Dopamine and noradrenaline are transformed by monoamine oxidase (MAO) to di- hydroxylated phenolic acids, DOPAC and DOMA, respectively. This reaction seems to take place mainly in the synthesizing cell 4, but the enzyme can probably de- grade also extracellular amines. The catecholamines can also be inactivated by catechol-O-methyl transferase (COMT), which seems to be localized far away from the synthesizing sites 4. At their passage to the ventricles and subarachnoidal space, the 3-O-methylated catecholamines and dihydroxylated phenolic acids are converted to the corresponding 3-O-methylated acids by MAO and COMT, respectively. The catecholamines and their metabolites are normally so slightly lipid soluble that they can only with difficulty diffuse through the lipid-like blood-brain barrier. This may be the reason why HVA and V1ViA occur in the cerebrospinal fluid in such high concentrations. They probably leave the central nervous system by filtra- tion through the arachnoidal villi 5. An active transport from cerebrospinal fluid to blood in the choroid plexus may also be possible 6,7. Zusammen/assung. Es wird papierchromatographisch gezeigt, dass Cerebrospinalflfissigkeit gesunder Menschen sowohl Homovanillins/iure als auch 3-Methoxy-4-hydroxy- mandels~iure enth~ilt. Die Konzentration der ersteren ist etwa 75 ng/ml und die der letzteren etwa 25 ng/ml. N.-E. ANDI~N, B.-E. Roos, and B. WERDINIUS s Department o/ Pharmacology, University o/G6teborg (Swe- den), March 11, 1963. a E. ROSENGREN, Acta physiol, scand. 49,370 (1960). 4 A. CARLSS0N and N.-A. HILLARP, Acta physiol, scand. 55, 95 (1962). 5 L. D. PROCKOP and L. S. SCHANKnR, Life Sciences 4, 141 (1962). a j. R. PAPPENHEIMER, S. R. HEISEY, and E. F. JORDAN, Amer. J. Physiol. 200, 1 (1961). 7 L.D. PROCKOP, L. S. SCIIANKER,and B. B. BRODIE, J. Pharmacol. /35,266 (1962). s Acknowledgment. This work has been supported by grants from Leo Ltd., H~ilsingborg, and from the Medical Faculty, University of G6tcborg (Sweden). For technical assistance we are indebted to Mrs. I. OLOFSON. The 'brown spots' (bsp) Character of Drosophila melanogaster and its Relation to Copulation The 'brown spots' (bsp) character arose spontaneously in the wild stock Aspra 52 of Drosophila melanogaster in 1959. The phenotypical manifestation is strictly limited to the female sex; it consists in the formation of brown- coloured areas, variable in shape and size, localized in the pleurae; the pigmentation (probably due to melanin) (DI PASQUALE 1) affects the hypodermic cells only (DI PASQUALE 2). The character is transmitted by the male as well as by the female; it is due to the presence of one or more reces- sive factors localized in the 2nd chromosome, and segre- gates normally in F 2 (DI 1)ASQUALEa). The penetrance varies in time from 60% to 90%. The phenotypical manifestation shows a clear relation to mating. Females kept apart from males, and females isolated from them when all the phases of courtship are complete but copulation has not yet taken place, never show spots. A high incidence of manifestation (63.3% sp. and 21.6% d.) 4, on tile other hand, is found when females are allowed to pair with males and are removed from them soon after the first copulation. Moreover, repeated copulations barely increase the degree of spotting. bsp females mated with males of nine different stocks (cn, Chieti-v, Cyl/Pm, Varese, tu B3, tu A2, Oregon, Urbana, y w) show in all cases typical spots generally with a high frequency; significant differences are, however, noticeable to a greater or lesser extent in the incidence in the bsp stock; the mating with y w males, in which the incidence of the spots is particularly low (9.5% sp. and 2.2% d.), is a peculiar case. Males of two different stocks, X/Y Le and X/O, sterile because of the non-motility of spermatozoa, the factors contained in the short arm of the Y chromosome being absent, also determine the appearance of spotting in bsp females. The same result is also obtained by pairing bsp females with X/X; tra/tra individuals. These, genotypic- ally females, are transformed into males owing to the presence of 'trans/ormer', a recessive gene localized in the 3rd chromosome (STURTEVANTS); they possess external genitalia and secondary sexual characters of male type, copulate regularly with females, have normal patagonia and rudimentary testes, and therefore do not produce spermatozoa. Interspecific mating between bsp females and Droso- phila simulans males also produces spotting, but with a low incidence (10.9% sp. and 1.1% d.). These investigations, therefore, prove that the ob- served response to mating is a general phenomenon; it is also independent of the sterility of the male, whether due to the non-motility of the spermatozoa or to their absence. Recent experiments using paper chromatography (CHEN and DIEM n) emphasize the presence of a ninhydrin- z A. DI PASQUALE, Atti A.G.I. 7, 138 (1962). 2 .~x.DI PASQUALE,Atti A.G.I. 5, 117 (1960). a A. DI PASQUALE,Atti A.G.I. 6, 233 (1961). 4 In these experiments it was preferred to classify separately the females with spots {sp.) and with very small pigmented areas (dottings, d.). 5 A.H. STURT~VA~T, Genet'cs 30, 297 (1945). P. S. CHEN and C. DIEM, J. Ins. Physiol. 7, 289 (1961).

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Page 1: The ‘brown spots’ (bsp) character ofDrosophila melanogaster and its relation to copulation

360 Br6ves communications - Kurze Mitteilungen EXPERIENTIA XlX[7

ce rebrosp ina l fluid) were car r ied t h r o u g h t he en t i r e pro- cedure in eve ry expe r imen t . Th i s is i m p o r t a n t , n o t on ly for t he ca lcu la t ion of t he recovery, b u t also for t h e qual i - t a t i v e d e t e r m i n a t i o n , because t h e p resence of o rgan ic m a t e r i a l usua l ly causes smal l changes in t h e Rf-va lues . B y th i s m e t h o d spots h a v e b e e n obse rved c o r r e s p o n d i n g in pos i t ion a n d colour to H V A a n d V MA a d d e d to cerebro- sp ina l fluid. T h e a m o u n t s of t h e acids were e s t i m a t e d s e m i q u a n t i t a t i v e l y on t he c h r o m a t o g r a m s . T he recover ies of H V A and VMA were a b o u t 40%. Af te r co r rec t ion for this , t h e n o r m a l c o n c e n t r a t i o n of H V A in ce reb rosp ina l f luid was e s t i m a t e d to a b o u t 75 n g / m l a n d of V MA to a b o u t 25 ng /ml . D O P A C a n d D O M A were no t found on the c h r o m a t o g r a m s . Nor was i t poss ib le to d e t e c t t h e m s p e c t r o p h o t o f l u o r i m e t r i e a l l y a f t e r c o n d e n s a t i o n w i t h e t h y l e n e d i a m i n e 3. The recover ies of a d d e d D O P A C a n d D O M A va r i ed b e t w e e n 50 a n d 60%.

The c a t e c h o l a m i n e s in t he cen t r a l n e r v o u s s y s t e m h a v e two i n a c t i v a t i n g p a t h w a y s . D o p a m i n e a n d n o r a d r e n a l i n e a re t r a n s f o r m e d b y m o n o a m i n e oxidase (MAO) to di- h y d r o x y l a t e d pheno l i c acids, D O P A C a n d DOMA, respec t ive ly . Th i s r e a c t i o n seems to t a k e place m a i n l y in t he syn the s i z ing cell 4, b u t t h e e n z y m e can p r o b a b l y de- g rade also ex t r ace l lu l a r amines . T h e c a t e c h o l a m i n e s can also be i n a c t i v a t e d b y c a t e c h o l - O - m e t h y l t r ans fe r a se (COMT), w h i c h seems to be local ized fa r a w a y f rom t h e s y n t h e s i z i n g si tes 4. A t t h e i r passage to t he ven t r i c les a n d s u b a r a c h n o i d a l space, t h e 3 - O - m e t h y l a t e d c a t e c h o l a m i n e s a n d d i h y d r o x y l a t e d pheno l i c acids are c o n v e r t e d to t he co r r e spond ing 3 - O - m e t h y l a t e d acids b y MA O a n d COMT, respec t ive ly . The c a t e c h o l a m i n e s a n d t h e i r m e t a b o l i t e s

are n o r m a l l y so s l ight ly l ip id soluble t h a t t h e y can on ly w i t h d i f f i cu l ty diffuse t h r o u g h t he l ipid- l ike b lood -b ra in bar r ie r . Th i s m a y be t he r ea son w h y H V A a n d V1ViA occur in t h e ce reb rosp ina l f luid in such h i g h c o n c e n t r a t i o n s . T h e y p r o b a b l y leave t h e cen t r a l n e r v o u s s y s t e m b y f i l t ra - t i on t h r o u g h t he a r a c h n o i d a l vil l i 5. A n ac t ive t r a n s p o r t f rom ce reb rosp ina l f luid to b lood in t he choro id p lexus m a y also be possible 6,7.

Zusammen/assung. Es wird p a p i e r c h r o m a t o g r a p h i s c h gezeigt, dass Cerebrospinal f l f i ss igkei t ge sunde r Menschen sowohl Homovan i l l i n s / i u re als a u c h 3 - M e t h o x y - 4 - h y d r o x y - mandels~iure enth~ilt . Die K o n z e n t r a t i o n de r e r s t e r en is t e t w a 75 n g / m l u n d die de r l e t z t e ren e t w a 25 ng /ml .

N. -E. ANDI~N, B. -E . R o o s , a n d B. WERDINIUS s

Department o/ Pharmacology, University o/G6teborg (Swe- den), March 11, 1963.

a E. ROSENGREN, Acta physiol, scand. 49,370 (1960). 4 A. CARLSS0N and N.-A. HILLARP, Acta physiol, scand. 55, 95 (1962). 5 L. D. PROCKOP and L. S. SCHANKnR, Life Sciences 4, 141 (1962). a j . R. PAPPENHEIMER, S. R. HEISEY, and E. F. JORDAN, Amer. J.

Physiol. 200, 1 (1961). 7 L.D. PROCKOP, L. S. SCIIANKER, and B. B. BRODIE, J. Pharmacol.

/35,266 (1962). s Acknowledgment. This work has been supported by grants from

Leo Ltd., H~ilsingborg, and from the Medical Faculty, University of G6tcborg (Sweden). For technical assistance we are indebted to Mrs. I. OLOFSON.

The 'brown spots ' (bsp) Character of Drosophila melanogaster and its Relat ion to Copulat ion

T h e 'brown spots' (bsp) c h a r a c t e r arose s p o n t a n e o u s l y in t he wi ld s tock Aspra 52 of Drosophila melanogaster in 1959.

T h e p h e n o t y p i c a l m a n i f e s t a t i o n is s t r i c t ly l imi ted to t he female sex; i t consis ts in t h e f o r m a t i o n of b r o w n - coloured areas , v a r i a b l e in shape a n d size, local ized in t h e p leu rae ; t h e p i g m e n t a t i o n ( p r o b a b l y due to me lan in ) (DI PASQUALE 1) affects t h e h y p o d e r m i c cells on ly (DI PASQUALE 2).

T h e c h a r a c t e r is t r a n s m i t t e d b y t h e ma le as well as b y t he female ; i t is due to t he p resence of one or more reces- sive fac tors localized in t h e 2nd ch romosome , a n d segre- gates n o r m a l l y in F 2 (DI 1)ASQUALEa). T h e p e n e t r a n c e var ies in t i m e f rom 60% to 90%.

The p h e n o t y p i c a l m a n i f e s t a t i o n shows a c lear r e l a t i on to ma t ing . Fema les k e p t a p a r t f rom males, a n d females i sola ted f rom t h e m w h e n all t h e phases of c o u r t s h i p are comple te b u t copu la t i on h a s n o t ye t t a k e n place, n e v e r show spots .

A h igh incidence of m a n i f e s t a t i o n (63.3% sp. a n d 21 .6% d.) 4, on t i le o t h e r h a n d , is f ound w h e n females are a l lowed to pa i r w i t h males a n d are r e m o v e d f rom t h e m soon a f t e r the f irst copula t ion . Moreover , r epea t ed copu la t i ons b a r e l y increase t h e degree of spo t t ing .

bsp females m a t e d w i t h ma les of n ine d i f fe ren t s tocks (cn, Chieti-v, Cyl/Pm, Varese, tu B3, tu A2, Oregon, U r b a n a , y w) show in all cases t y p i c a l spo t s genera l ly w i t h a h igh f r equency ; s ign i f ican t differences are, however , no t i ceab le to a g rea t e r or lesser e x t e n t in t h e inc idence in t h e bsp s tock ; t h e m a t i n g w i t h y w males , in w h i c h t he

inc idence of t h e spots is p a r t i c u l a r l y low (9.5% sp. a n d 2 .2% d.), is a pecu l i a r case.

Males of two d i f f e ren t s tocks, X / Y Le a n d X/O, s ter i le because of t he n o n - m o t i l i t y of spe rma tozoa , t h e fac tors c o n t a i n e d in t h e s h o r t a r m of t he Y c h r o m o s o m e be ing absen t , also d e t e r m i n e the a p p e a r a n c e of s p o t t i n g in bsp females. T h e s a m e resu l t is also o b t a i n e d b y pa i r i ng bsp females w i t h X / X ; tra/tra ind iv idua l s . These, geno typ ic - a l ly females, a re t r a n s f o r m e d in to ma le s owing to t h e p resence of 'trans/ormer', a recess ive gene localized in t h e 3rd c h r o m o s o m e (STURTEVANTS); t h e y possess e x t e r n a l gen i t a l i a a n d s e c o n d a r y sexua l c h a r a c t e r s of ma le type , copu l a t e r egu la r ly w i t h females, h a v e n o r m a l p a t a g o n i a a n d r u d i m e n t a r y tes tes , a n d the re fo re do n o t p roduce s p e r m a t o z o a .

In te r spec i f i c m a t i n g b e t w e e n bsp females a n d Droso- phila simulans males also p roduces spo t t ing , b u t w i t h a low inc idence (10.9% sp. a n d 1.1% d.).

These inves t iga t ions , the re fore , p r o v e t h a t t h e ob- se rved r e sponse to m a t i n g is a genera l p h e n o m e n o n ; i t is also i n d e p e n d e n t of t h e s t e r i l i t y of the male, w h e t h e r due to t h e n o n - m o t i l i t y of t he s p e r m a t o z o a or to t h e i r absence .

R e c e n t e x p e r i m e n t s us ing p a p e r c h r o m a t o g r a p h y (CHEN a n d DIEM n) e m p h a s i z e t he p resence of a n i n h y d r i n -

z A. DI PASQUALE, Atti A.G.I. 7, 138 (1962). 2 .~x. DI PASQUALE, Atti A.G.I. 5, 117 (1960). a A. DI PASQUALE, Atti A.G.I. 6, 233 (1961). 4 In these experiments it was preferred to classify separately the

females with spots {sp.) and with very small pigmented areas (dottings, d.).

5 A.H. STURT~VA~T, Genet'cs 30, 297 (1945). P. S. CHEN and C. DIEM, J. Ins. Physiol. 7, 289 (1961).

Page 2: The ‘brown spots’ (bsp) character ofDrosophila melanogaster and its relation to copulation

15. VII. 1963 Brevi conmnicazioni - Brief Reports 361

posi t ive substance, previous ly descr ibed by F o x et al. 7 as 'sex pep t ide ' , pecul iar to the male ; th is is found only in the pa tagon ia and its a m o u n t increases in concent ra t ion from the 1st to the 9th day of the adul t stage.

Accord ing to this f inding the fol lowing exper iment was set up to inves t iga te whe the r differences in incidence of spots could be re la ted to the a m o u n t of paragonial sub- s tance in the glands of the copula t ing male.

Individuals of the same age, aged ]tom 2 to 8 days, bsp males and bsp females, isolated on emerging, were al lowed to m a t e when the desired age was reached ; when one copula t ion had t aken place, the male was removed.

The results of count ing are repor ted in F igure 1. I t can clearly be seen t h a t the f requency of ma t ing increases wi th age; b o t h f requency and size of spots increase too, reaching the i r m a x i m u m on the 6th day, while do t t i ng f requency, h igher on the 2nd day when the spots are few, decreases dur ing the successive days, showing a sym- met r ica l pa t t e rn .

Contro l males and females were m a t e d in single pairs soon af te r emergence and lef t t oge the r unt i l count ing. The incidence of the spots was no t v e r y h igh and the size r a the r small ; the mor t a l i t y among females was par t icu- lar ly high.

To inves t iga te whe the r the de tec ted increase in spots rea l ly depends on the age of the male, the fol lowing expe r imen t was made : males aged f rom 2 to 9 days were al lowed to ma te wi th females of a f ixed age, 5 days old; reciprocal ly, females aged f rom 2 to 9 days were paired wi th 5-day-old males. The mode of collecting, isolat ing and pair ing flies was the same as in the previous experi- m e n t ; the age of 5 days was chosen, owing to t he high incidence of spots previous ly found.

The following resul ts were obtained. (a) males o / 2 to 9 days × #males o/ 5 days (Figure 2): the f requency of mat ing , h igh on all days, progresse s regular ly, showing two low points on the 3rd and the 6th day. The f requency of the spots is cons tan t ly v e r y high, and decreases signifi- can t ly on the 3rd and the 6th day ; on the o ther hand, the f r equency of do t t ing is low, and i t follows a t r end opposed to t h a t of the spots. The size of the spots, fair ly large, is more or less cons tan t in t ime.

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~ /~ / , / ~ ~ - - . . o ° " Frequency of ma ling / ~ s + c t o M i n g . s / o ~ Spots

2 3 t, 5 6 7 8 Age in days

(b) Females o / 2 to 9 days × males o] 5 days (Figure 3) : the f requency of m a t i n g is h igh and constant , and shows a s ignif icant decrease on the 3rd and the 6th day. The fre- quency of the spots, low on the 2nd and the 3rd day, increases on the fol lowing days, excep t on the 6th day, where a decrease is not iceable. The size of the spots, ve ry small on the 2nd and the 3rd day, becomes larger dur ing the fol lowing days. The f requency of do t t ing shows a symmet r ica l pa t t e rn opposed to t h a t of spots.

Controls gave the same resul t as in the previous experi- ment .

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. . . . . Frequency of mating = ~Spo?s+dollings o o Spots '~ =Dottings

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Fig. 2. Diagram showing the same phenomena as Figure 1 ; mating between 2-9 days old males and 5 days old females.

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q~, '*.~% ##

. . . . . Frequency ot mating ,- =Spots+dottings o o Spots

~ Dottings

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Fig. 3. Diagram showing the same phenomena as F gurc 1 and 2; mat ng between 5 days old males and 2-9 days old females.

Fig. 1. Diagram showing the frequency of spots and dottings and the frequency of nlating between individuals of the samc age, in different

days. A. S. Fox, C. D. MEAD, and I. L. MuNYoN, Science 129, 1489 (1959).

Page 3: The ‘brown spots’ (bsp) character ofDrosophila melanogaster and its relation to copulation

362 Br6ves coummnications - Kurze Mittcilungen EKPERIENTIA XlX]7

Discussion. F r o m the resu l t s p r e s e n t e d so far, i t is c lear t h a t t h e p h e n o t y p i c a l m a n i f e s t a t i o n of t h e ' b r o w n spo t s ' c h a r a c t e r is s t r i c t l y d e p e n d e n t on copu la t ion .

The d a t a are no t ye t suf f ic ient to exp la in t h e n a t u r e of t h e p h e n o m e n o n ; t h e y a l low us, however , to h y p o t h e s i s e t he exis tence of one of two d i f fe ren t m e c h a n i s m s , e i t h e r of which for the m o m e n t a p p e a r s equa l ly likely.

(a) I t m i g h t be sugges ted t h a t t h e s p e r m f luid is re- sponsible for i n d u c i n g t h e s p o t t i n g process. T h e f luid could p roduce a r eac t i on in t h e bsp females owing t o t h e p resence in i t of a pecu l ia r s u b s t a n c e ; o therwise , a n in- fec t ing a g e n t p r e s e n t in t h e f lu id could give rise to spo ts f o r m a t i o n w h e n i n t r o d u c e d in t he bsp female. I n th i s l as t case i t would b e necessa ry to p o s t u l a t e a w idesp read a g e n t ; in fac t i t would be p r e s e n t in all males of t h e t e s t ed stocks.

One m i g h t also suppose t h a t t h e s p e r m f luid m e r e l y a c t i v a t e s a s u b s t a n c e or a n in fec t ing a g e n t a l r e a d y p re sen t in t h e bsp females.

(b) Accord ing to a n o t h e r m e c h a n i s m , i t could be as- s u m e d t h a t s p o t t i n g m a y be due to a r eac t i on b r o u g h t a b o u t in t h e female b y he r ac t ive p a r t i c i p a t i o n in copu- la t ion , i r r e spec t ive of t he f lu id i n t roduced . I n th i s case we shou ld be c o n f r o n t e d w i t h a h o r m o n a l reac t ion .

Because of t h e c lear c o n n e c t i o n b e t w e e n t he age of t h e female a t t h e m o m e n t of c o p u l a t i o n a n d t h e f r e q u e n c y a n d size of spots , we m u s t p o s t u l a t e t h a t t h e c o n t r i b u t i o n suppl ied b y t h e ma le is c o n s t a n t t h r o u g h o u t life.

A t t he same t i m e we m u s t conc lude t h a t t h e response suppl ied b y t h e f emale is more or less i n t ense acco rd ing to

he r age, t h e m e c h a n i s m a t work b e i n g due to a specif ic cause c o n t a i n e d in t he s p e r m fluid or to a h o r m o n a l reac- t ion .

T h e di f ferences in spo t f r e q u e n c y r e l a t ed to t he ag ing of t h e female could m e r e l y cons is t in a c a p a c i t y to pro- duce b r o w n p i g m e n t w h i c h changes w i t h age.

I n a n y case, t h e di f ferences in inc idence o b t a i n e d in m a t i n g bsp females to ma le s of va r i ous s tocks d e m o n - s t r a t e t h a t t h e ma le g e n o t y p e is respons ib le u p to a p o i n t for t h e e x t e n t of t h e m a n i f e s t a t i o n s .

Riassunto. Le a u t o r i d i m o s t r a n o c h e l a m a n i f e s t a z i o n e del feno t ipo neUe f emin ine omoz igo t i pe r il c a r a t t e r e bsp

p r o v o c a t a da l la copulaz ione . L ' a c c o p p i a m e n t o con m a s c h i di ceppi n o n bsp e con m a s c h i s ter i l i (X/yL% X]O, X / X ; tra/tra) d e t e r m i n a p u r e la c o m p a r s a delle macch i e helle f e m m i n e bsp, d i m o s t r a n d o che il f e n o m e n o 6 indi - p e n d e n t e da l la p r e senza degli s p e r m a t o z o i nel lo spe rma . Es i s te u n a re laz ione f ra f r e q u e n z a del la m a n i f e s t a z i o n e ed e t a de l la f e m m i n a al m o m e n t o d e l l ' a c c o p p i a m e n t o .

A. DI PASQUALE a n d L. ZAMBRUNI

Istituto di Genetica, Universith di Milano (Italy), February l l, 7963.

s This investigation was supported financially by the Consiglio Naz!onale delle Rieerehe, Roma.

T h e I n t e r f e r e n c e of T r y p t o p h a n e in the E s t i m a t i o n of F r u c t o s e by the R e s o r c i n o l M e t h o d

I n our ear l ier s tud ies w i t h h u m a n semen, i t was ob- se rved t h a t f ruc tose va lues of s emen as e s t i m a t e d b y t he resorc inol m e t h o d of RoE 1 were a lways h i g h e r t h a n t hose o b t a i n e d b y t h e c h r o m a t o g r a p h i c m e t h o d (SHETH a n d RAO2,3). The yeas t f e r m e n t a t i o n t e s t s ca r r i ed o u t w i t h h u m a n semen h a v e also i n d i c a t e d t h a t t h e resorc ino l m e t h o d is n o t v e r y specif ic for t h e e s t i m a t i o n of f ruc tose in h u m a n s e m e n (SHETH a n d RAO3). I n t h e p r e s e n t inves - t iga t ion , a t t e m p t s were m a d e to f ind o u t t h e n a t u r e of t h e s u b s t a n c e s p r e s e n t in h u m a n s e m e n w h i c h in te r fe re w i t h t he e s t i m a t i o n of f ruc tose b y t he resorc ino l m e t h o d .

JORDAN a n d PRYDE a a n d POGI~LL s h a v e s h o w n t h a t f ructose r eac t s w i t h t r y p t o p h a n e in t h e p resence of con- c e n t r a t e d hyd roch lo r i c acid to fo rm a p u r p l e co loured produc t . As s h o w n ear l ier , t r y p t o p h a n e was found to be p r e sen t in h u m a n semen (SHETH a n d RAo6). Ana lyses of 9 semen samples h a v e s h o w n t h a t t h e t r y p t o p h a n e con- t e n t of t he semen, e s t i m a t e d acco rd ing to t he m e t h o d of FISCI4L 7, was a n y w h e r e f rom 0.6 to 2.4 m g pe r ml.

E x p e r i m e n t s were the re fo re ca r r ied o u t to see w h e t h e r t r y p t o p h a n e would in te r fe re w i t h t he e s t i m a t i o n of fruc- tose b y t he resorc inol m e t h o d . P r e l i m i n a r y e x p e r i m e n t s showed t h a t 0.2 m g of t r y p t o p h a n e b y i tsel f d id n o t fo rm a n y colour w i th resorcinol . I n t h e s u b s e q u e n t e x p e r i m e n t , f ructose was e s t ima ted in t he p resence of t r y p t o p h a n e . As seen f rom t h e F igure in t h e p resence of 0.2 m g of t r y p t o - p h a n e , f ructose va lues were a lways h ighe r (0.07 to 0.16 mg]ml) as c o m p a r e d w i t h t h e f ruc tose va lues ob- t a i n e d in t h e absence of t r y p t o p h a n e . F o r t he e s t i m a t i o n of s emina l f ructose b y t h e resorcinol m e t h o d 0.1 ml of s emen is employed (MANN S). As a l r eady shown, t h i s q u a n - t i t y of semen would c o n t a i n 60 ~g to 240 vg of t r y p t o -

p h a n e . The resu l t s r e p o r t e d i n d i c a t e t h a t th i s c o n c e n t r a - t i o n of t r y p t o p h a n e wou ld ser ious ly in te r fe re w i t h t h e e s t i m a t i o n of f ruc tose b y t he resorc inol m e t h o d . ,0[

0,8 / "

=>,0.6 "..,~ -~ O.t+ ,,4"

13.2

d.1 Oi d.3 d.4. d.5 Fruc~ose(mgb

Graph showing the interference of tryptophane in the estimation of fructose by the resorcinol method. • - • Fructose values in the presence of 0.2 mg of tryptophane, o - o Fructose values in the

absence of tryptophanc.

t j . H. Ro~, J. biol. Chem. 211, 143 (1934). A. R. S~iExn and S. S. RAO, Exper. 16, 314 (1959).

3 A. R. SHETn and S. S. RAo, Indian J. reed. Sei. 16, 709 (196~2). 4 R. C. JORDAN and J. PRYDE, Biochem. J. 32, ~279 (1938).

B. M. POOELL, J. biol. Chem. 211, 143 (1954). n A. R. SHETH and S. S. RAo, Indian J. med. Sci. 16, 24 (1961).

J. FlSCHL, J. biol. Chem. 235, 999 (1959). s T. MANN, Lancet 254, 446 (1948).