Millipede Luminodesmus sequoiae Diplopoda

The phylum Arthropoda includes the classes Diplopoda (millipedes), Chilopoda (centipedes), Crustacea (see Chapter 3), and Insecta (see Chapter 1). All luminous arthropods other than crustaceans are terrestrial, and not very many luminous millipedes and centipedes are known. The luminescence of millipedes is usually intracellular, whereas luminous centipedes discharge luminous secretion. Substantial chemical studies have been made only with the millipede Luminodesmus sequoiae and the centipede Orphaneus brevilabiatus, of which the latter is discussed in the Section 10.3. 

Davenport et al. (1952) were unsuccessful in their attempts to restore the luminescence of the filtered aqueous extract of Luminodesmus. Hastings and Davenport (1957) saw a weak luminescence in their filtered aqueous extracts made from the acetone powder of the millipedes. They found that the luminescence is dependent on pH, with an optimum at about pH 8.9, and that the light intensity could be increased by 10-30% by adding ATP. Hastings and Davenport also measured the luminescence spectrum of live animals, finding an emission peak at 495 nm. 

an active photoprotein was extracted and purified from L. sequoiae and its properties were investigated (Shimomura, 1981, 1984). The results are summarized below. 

Specimens of L. sequoiae were collected in the vicinity of Camp Nelson, California, in May 1980 and April 1982 and 1983. The specimens were anesthetized with chloroform vapor, and their guts were pulled out from the head or tail and discarded. The body shells (terga) were frozen with dry ice, and kept at —75°C until use. 

The frozen shells were ground in a cold mortar with 50 mM sodium acetate buffer, pH 5.8, containing 10 mM EGTA and 0.2 M NaCl, then the mixture was centrifuged. The pellets were re-extracted with the same buffer, and centrifuged. All supernatants were combined, and the photoprotein was precipitated with ammonium sulfate. The photoprotein in the precipitate was purified by four steps of column chromatography at near 0°C. Due to the instability of the photoprotein, efforts were made to reduce the time required for purification. 

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