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Any quantitative investigations of fluorescence phenomena more or less presuppose some information as to the spectral emission curve of the substances under investigation. Knowledge of the shape of the slpectral emission curves of pure substances is necessary to various degrees of accuracy for the identification of pigments by fluorescence, for the detection of fluorescent impurities in mixtures, for the appropriate selection of filters or photocells to measuire the fluorescence intensity, and for planning experiiments so as to avoid reabsorption of the fluorescence within the sample. Reliable curves for the pure substances are particularly necessary for the analysis of the fluorescence spectra of complex fluorescent mixtures or of living cells. The fluorescent properties of chlorophyll have been investigated from many points of view since the fluorescence of chlorophyll was discovered by Brewster in 1834. Stokes, who discovered the basic principles of fluorescence, also found that chlorophyll fluoresces in leaves. In spite of the widespread occurrence in nature of chlorophyll and its scientific importance we know of only one investigation, Zscheile and Harris (32), reporting the precisely meastured fluorescence spectra of pure chlorophylls a and b.The fluorescence spectrum of bacteriochlorophyll in solution has been measured by Vermeulen, Wassink, and Reman (27) and in the intact bacteria by Duysens (9). The present paper revises slightly the calculations upon which Zscheile and Harris based their curves and presents precise curves for other plant pigrments, particularly those concerned in the process of photosynthesis.The yield of chlorophyll fluorescence in polar solvents has recently been found by Livingston and Forster (18) to be 25 %, in contrast to the older accepted value of 10 %. The low fluorescence in pure non-polar solvents and the enhancement of its intensity by traces of polar solvents has been studied by Watson, and McArdle (19 (13,14,15,23,29,30).Fluorescence spectroscopy of photosynthetic pigments in live plants has been used in studying energy transfer from one pigment to another

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AND G. ELIZABETH FOERSTER. Enzymes associated with bioluminescence in Panus stypticus luminescens and Panus stypticus non-luminescens. J. Bacteriol. 88:1372-1379. 1964.-Fungal bioluminescence depends upon at least four factors: (i) reduced nicotinamide adenine dinucleotide (NADH) (or reduced nicotinamide adenine dinucleotide phosphate); (ii) a molecule to accept electrons, either directly or indirectly from NADH; (iii) an enzyme(s) to catalyze electron transfer; and (iv) luciferase to catalyze the actual light-emitting reaction. Cell-free light emission from Panus stypticus luminescens was obtained, and the enzymes of this species are interchangeable, in all combinations, which those of another luminous fungus, Collybia velutipes. A study of the nonluminous form of Panus stypticus indicates that both enzymes are absent in this strain, and no definite conclusion could be made regarding the presence or absence of the electron acceptor. The genetic implications of these findings are discussed.

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Svedberg and Katsurai (1929) proposed a phylogenetic nomenclatural system for the classification of the phycobilin pigments of the algae. They designated the phycoerythrin and phycocyanin from the red algae as R-phycoerythrin and Rphycocyanin, respectively, and the corresponding pigments from the blue-green algae as C-phycoerythrin and C-phycocyanin. In general, these pigments exhibit the following absorption maxima : Approximate absorption maxima Pigment m/< R-phycoerythrin 495 540 560 C-phycoerythrin 550 R-phycocyanin 550 615 C-phycocyanin 615This system has proved inadequate in several instances (Kylin, 1912;Lemberg, 1930;Kylin, 1940; Haxo, ct a!., 1955) in that phycobilin pigments other than the above types, as judged from their absorption spectra, have been isolated. In spite of the apparent shortcomings of the Svedberg and Katsurai system of classification, no new system has been proposed. A new phycoerythrin has now been isolated from Porphyra naiadum and it is proposed that this pigment be called B-phycoerythrin (tentatively so designated by Blinks, 1954). This differs from known phycoerythrins in having two absorption peaks, at 545 and 565 nip.. The isolation, purification and some properties of this pigment will be discussed. SOURCEPorphyra naiadum Anderson is a member of the most primitive red algal order, the Bangiales. There is now some question as to whether it belongs in the genus Porphyra, since its life cycle is different. This is currently under study by Prof.G. J. Hollenberg ; pending his description of a new genus, we must use the current name. The thallus is one cell thick, extremely delicate, and yields its pigment readily into fresh water in a few hours. It is found growing only upon a marine flowering plant, Phyllospadi.v.