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Biomedical subjects

M J Cormier

Publications and source records attributed to M J Cormier.

At least 55 records · Page 3Linked to original sources
PubMed1975

Spectral characteristics of the bioluminescence induced in the marine fish, Porichthys notatus by Cypridina (ostracod) luciferin.

Specimens of Porichthys notatus, which are naturally luminous along the coast of California, are non-luminous in Puget Sound. However, luminescence capability may be induced in the adult Puget Sound Porichthys by the administration of purified Cypridina (ostracod) luciferin, synthetic Cypridina luciferin, or Cypridina organisms. The bioluminescence emission spectra produced by the Puget Sound fish following induction is similar, if not identical, to that of the naturally luminous Porichthys notatus from California waters (maxima: 485 and 507 nm).

Animals↗
PubMed1975

Renilla luciferin as the substrate for calcium induced photoprotein bioluminescence. Assignment of luciferin tautomers in aequorin and mnemiopsin.

A study was made of the effects of pH and protic and aprotic solvents on the spectral properties of Renilla (sea pansy) luciferin and a number of its analogs. The results have made possible the assignment of two tautomeric forms of Renilla luciferin, one which absorbs maximally at 435 nm and another which exhibits an absorption maximum at 454 nm. Furthermore the results provide an explanation for the visible absorption characteristics of the photoproteins aequorin (lambda-max 454 nm) and mnemiopsin (lambda-max 435 nm). In addition a Renilla-like luciferin can be extracted from both of these photoproteins. This luciferin produces light with Renilla luciferase, at a rate dependent upon the concentration of dissolved oxygen, and in other respects is indistinguishable from Renilla luciferin in this bioluminescent reaction. The results suggest that the native chromophore in both photoproteins is Renilla luciferin (or a nearly identical derivative). The results also suggest that a hydroperoxide intermediate probably exists in photoproteins, on energetic grounds, and to account for the oxygen concentration independency of the rate of photoprotein reactions. This hydroperoxide may be attached initially to an amino-acid side chain (possibly indolyl-OOH, imidazoyl-OOH, or -SOOH) rather than to the luciferin chromophore.

Aequorin↗
PubMed1975

Extraction of Renilla-type luciferin from the calcium-activated photoproteins aequorin, mnemiopsin, and berovin.

Photoproteins, which emit light in an oxygen-independent intramolecular reaction initiated by calcium ions, have been isolated from several bioluminescent organisms, including the hydrozoan jellyfish Aequorea and the ctenophore Mnemiopsis. The system of a related anthozoan coelenterate, the sea pansy Renilla reniformis, however, is oxygen dependent, requiring two organic components, luciferin and luciferase. Previously published indirect evidence indicates that photoproteins may contain a Renilla-type luciferin. We have now extracted in high yield a Renilla-type luciferin from three photoproteins, aequorin (45% yield), mnemiopsin (98% yield), and berovin (85% yield). Photoprotein luciferin, released from the holoprotein by mercaptoethanol treatment and separated from apo-photoprotein by gel filtration, no longer responds to calcium but now requires luciferase and O2 for light production. Photoprotein luciferin is identical to Renilla luciferin with respect to reaction kinetics and bioluminescence spectral distribution. In view of these results, the generally accepted hypothesis that the photoprotein chromophore is a protein-stabilized hydroperoxide of luciferin must be modified. We believe, instead, that the chromophore is free luciferin and that oxygen is bound as an oxygenated derivative of an amino-acid side chain of the protein. We propose the general term "coelenterate luciferin" to describe the light-producing chromophore from all bioluminescent coelenterates and ctenophores.

Aequorin↗
PubMed1975

A fine structure study of the anthocodium in Renilla mülleri. Evidence for the existence of a bioluminescent organelle, the luminelle.

A fine structure study of the anthocodium of the sea pansy, Renilla mülleri, was undertaken. The anthocodium, a known site of bioluminescence, was selected in order to determine whether a structural entity could be found which would satisfy the biochemical and physiological features associated with the known sites of bioluminescence in this animal. These sites, termed lumisomes, have previously been shown to be small (0.1-0.2 mum), membrane-enclosed vesicles which contain all the proteins necessary for bioluminescence and its immediate control. One of the lumisomal proteins is an intensely green fluorescent protein and has been used as a probe for the detection of the cellular sites of bioluminescence. This green fluorescence was associated only with gastrodermal cells. We report the identification of a unique morphological entity, restricted to the cells of the gastrodermis, which satisfies the biochemical and physiological requirements for bioluminescence in Renilla. It is a large (4-6 mum), membrane-bounded subcellular organelle comparable in size to a subcellular structure whose green fluorescence is typically associated with the in vivo bioluminescence. Furthermore, it is filled with smaller membrane-bounded vesicles which have the same size and shape as the lumisomes. We suggest that the organelle identified in this study be termed a luminelle.

Cnidaria↗
PubMed1973

Structure and chemical synthesis of a biologically active form of renilla (sea pansy) luciferin.

The structure of a biologically active form of Renilla (sea pansy) luciferin has been elucidated; this structure, confirmed by total chemical synthesis, is 3,7-dihydro-2-methyl-6-(p-hydroxyphenyl)-8-benzylimidazo [1,2-a] pyrazin-3-one. In the natural compound the methyl group at the 2 position is replaced by an unknown, more complex group. For this reason the synthetic compound is 10% as active as the natural compound in producing light with Renilla luciferase. However, the spectral properties of the two compounds are identical. In addition the rates of the luminescent reaction with both compounds are similar, and the color of the light produced is identical in each case.A compound isolated from the calcium-triggered photoprotein aequorin has been identified by Shimomura and Johnson [(1972) Biochemistry 11, 1602] to be 2-amino-3-benzyl-5-(p-hydroxyphenyl)pyrazine. This compound forms an integral part of the structure of Renilla luciferin. This, and other evidence, suggests that the structure elucidated for Renilla luciferin is a more general one associated with the luciferins of most, if not all, bioluminescent coelenterates.

Journal Article↗