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COMMUNICATIONS Comments relating to articles which have recently appeared in the

Journal of Cellular and Comparative Physiology and brief descrip- tions of important observations will be published promptly in this Section. Preliminary announcements of material which will be pre- sented later in more extensive form are not desired. Communications should not in general exceed 700 words.

NOTE ON THE RED LUMINESCENCE AND THE RED PIGMENT OF THE “RAILROAD WORM”

E. NEWTON HAXVEY Physiological Laboratory, Princeton University, Princeton, New Jersey and

Marine Biological Laboratory, Woods Hole, Massachusetts

In a recent communication the author (’44) described the red and green luminescence of the South American phengodid beetle larva, Phryxothrix, the so-called “railroad worm.” I t was shown that the red luminescence is dependent on oxygen and is an actual emission of light and not a selective absorption by a red pigment. The red lumines- cence comes from colorless tissue within the head and can be seen when the head is dissected open and the tissue observed directly rather than through the brownish chitin. This fact has been confirmed in recent observations on new specimens received from H. H. Parker of Monte- video, Uruguay.

The previous observation that no red fluorescence appears from the head when irradiated with near ultraviolet light (without the visible) was also confirmed. In addition, it was found that there was no red fluorescence when the head is irradiated with blue, green, yellow or red light. These facts suggest that no porphyrin is present, as the red fluo- rescence of porphyrins is well known. We might abandon the idea that porphyrin is involved in light production, except for the fact that porphyrin in combination is not always fluorescent. For example, hemo- globin is not, although hematoporphyrin is markedly fluorescent.

It is also attractive to assume that the red chemiluminescence is con- nected with oxidation of some porphyrin compound. Ever since the

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186 JOURNAL 0 F CELLULSR AND COMPARATIVE PI€YSIOLOGY

studies of IIelberger ( '38) and Rothemund ( '38) the red chemilumin- escences of metal porpliyrin complexes have been well known. An easy and striking method of demonstrating this red chemiluminescence is to drop a small amount of dried powdered spinach leaves into a flask of boiling tetralin ( tetrahydronaphthalene). The red cliemiluminescence gives the appearance of a liquid glowing with the dull red heat of molten iron. The light is due to peroxides which a re present in the tetralin as impurities and which oxidize the porphyrin of chlorophyll with tbe accompaniment of red luminescence.

The existence of a red pigment in the body of the animal is again suggestive of a porphyrin. I had previously observed this pigment to be extruded when the animal was roughly handled. The new specimens have revealed that this red material comes from the anus. On dissecting the animal, the last third of the intestine, posterior to the entrance of the two malpighian tubules, is seen to be filled with a bright red oily fluid. This liquid sticks to paraffin and rises as globules to the surface of Ringer's solution without readily mixing with it. The red pigment could be produced in the malpighian tubules, although this is not cer- tain. It frequently covers the outside of the anterior segments of the body because of the strong tendency for the larva to coil up with tail end near head end, but it is completely absent within the head where the red light is emitted.

When mixed with water the red color becomes more yellowish and on standing turns brown. When absorbed on cotton or filter paper the initially red spot also turns brown. However, the concentrated red oily liquid will remain red for some time in a moist chamber. Dr. George I. Lavin of the Rockefeller Institute has kindly taken a series of absorp- tion spectograms of the red liquid, using the Hilger quartz 34 inch by 44 inch spectograph. Light from a 75-watt Mazda lamp passed through the red material and the absorption spectrum was photographed on Wratten M panchromatic plates. The far ultraviolet spectrum was not obtained. A scale and a calibration with lines from the mercury vapor arc were also photographed. The exposures ranged from 10 minutes to 0.1 second.

The red pigment has maximum transmissjon at about 600 mp wave length and some transmission on 10-minute exposure between 470 and at least 700 mp, since 700 mp is the limit of red sensitivity of the plate. The fresh red pigment shows no absorption bands entirely in the visible. It is not yet known how fa r the absorption, beginning at 470 mp con- tinues into the ultraviolet. A sample of the red pigment somewhat diluted with water and 2 days old transmitted a somewhat greater

COMMEXTS AND COMMUNICATIONS 187

range of wave lengths and showed a possible very broad absorption band in the neighborhood of 420 mp.

I n the absence of definite absorption bands the red pigment appears quite unrelated to porphyrins. It is also different from the lampyrine of Metcalf ( ’43) which had an ahsorption band between the yellow and green at 565 my. Some of the carotinoids (capsanthin) and astacin (from Astacus gammarus) have general absorption between 550 and 400 my with a maximum around 480 mp. The red pigment might be a caro- tinoid except for the red fluorescence. In dilute solution, there is no marked fluorescence in ultraviolet light but the concentrated material newly removed from the gut is red fluorescent in the light from a mer- cury vapor arc passed through both the Corning G 586 A (ultraviolet) and G 584 J (blue) filters. This combination transmits no red from the mercury are, so that the red light of the pigment must be a fluorescence. In this respect it resembles red fluorescent lampyrine but more material will be necessary to establish the class of pigments to which it belongs. The red material in the intestine might serve as a reservoir of some luminescent compound or some precursor, which is supplied in low concentration to the proper enzyme of the head and oxidized with light emission. However, such a rncchanism has yet to be proven.

SUMMARY

No red fluorescence of the red luminous material of the head of Phryx- othrix is excited by the near ultraviolet or by blue, green, yellow or red light.

A red pigment is pqsen t in that par t of the alimentary tract posterior to the entrance of the Malpighian tubules. The oily red sub- stance is expelled from the anus when the animal is disturbed. The red pigment possesses no narrow absorption bands in the visible regions, but general absorption in the blue extending into the ultraviolet. The red pigment might be a carotine ; it does not appear to be a porphyrin or to be connected with the red luminescence of Phryxothrix.

LITERATURE CTTED

HARVEY, E. N. 1944

HELBERGER, J. H.

METCALF, R. L.

ROTHEMUND, P.

The nature of the red and green luminescence of the South American

Uber eine neiien Fall von Chemiluminescence. Naturwiss., Bd. 26,

The isolation of a red fluorescent pigment, lampyrine, from the Lainpy-

Chemiluminescence of the clilorophylls and some other porphyrin metal

“Railroad worin,” Phryxothrix. J. Cell. and Comp. Physiol., vol. 23, pp. 31-38. 1938

S. 316-317. 1943

1938 ridae. Ann. Extom. SOC. America, vol. 36, pp. 39-40.

complexes. J. Am. Chem. Soc., vol. 60, p. 2005.