Effects of Culture Conditions on Mycelial Growth and Luminescence in Panellus stypticus

Abstract

A pure culture ofPanellus stypticus was isolated from a mature basidiocarp and studied for its growth and luminescence abilities under various environmental and nutritional conditions. The culture was non-luminous growing submerged in defined liquid media with or without agitation. After a two-to three-day lag period on solid substrata, luminescence increased exponentially with a doubling time of 4 hours while the increase in colony radial growth was linear. On solid substrata, growth and total light emission were strongly correlated under most conditions studied. Optimal conditions included darkness; 28 C; pH 3.8; glucose, maltose, trehalose, cellobiose or pectin as carbon source; and ammonia or asparagine as nitrogen source. Growth and luminescence were inhibited by ambient fluorescent light. Dark-grown colonies were brightest in the center while light-grown colonies were brightest at the pe? riphery. Cultures hydrolyzed starch and produced an extracellular phenoloxidase. Conditions for pro? duction of luminescent basidiocarps by this culture are described.Key Words: Panellus stypticus, luminescence, bioluminescence, defined media Understanding the physiology of luminescent fungi and its relationship to light emission is im? portant for several reasons. First, luminescence is rapidly and sensitively measurable in vivo and thus constitutes a endogenous reporter system that may help to reveal physiological interrelationships with environmental parameters. Sec? ond, expression of luminescence may be spatially resolved within a colony or basidiocarp and thus used as a marker for gene expression and differentiation. Finally, optimization of light emission by fungal cultures in the laboratory may aid in studies of its biochemistry.Several quantitative studies of the physiology of fungal luminescence (e.g., Hastings, 1952; Foerster, 1960,1965;Berliner, 1961aBerliner, , b, 1963Berliner and Brand, 1962;Foerster et al, 1965;Calleja and Reynolds, 1970a; Kamzolkena, 1982) and its biochemistry (Airth and McElroy, 1959; Foerster, 1962,1964;Airth et al., 1966;Kuwabara and Wassink, 1966;Endo et al, 1970, Kamzolkena et al, 1983Isobe et al, 1987Isobe et al, ,1988Nakamura et al, 1988;Shimomura, 1989) have been reported. However, the luminous fungus for which physiology in relationship to its light emission is best understood has been reported as Col? lybia velutipes (Curt. ex Fr.) Kummer (= Flammulina velutipes (Curt. ex Fr.) Sing.) (Airth and McElroy 1959;Foerster, 1962, 1965;Foerster et al, 1965;Airth et al, 1966), although it is of dubious identity (Wassink, 1978). When strains of Flammulina velutipes obtained from the Culture Collection at the Center for Forest Mycology Research, University of WisconsinMadison (OKM 6261-sp) and by tissue culture were studied, neither basidiocarps nor mycelia

Low-Level Bioluminescence Detected in Mycena haematopus Basidiocarps

“…Maximum light emission occurred at the pe riphery of the culture when grown under normal laboratory light conditions. Similar results were reported by Bermudes et al (1990) for Panellus stypticus. Comparison of the light emission levels of some bioluminescent cultures is presented in Fro.…”

The effect of culture conditions on the mycelial growth and luminescence of naturally bioluminescent fungi

“…Airth et al [10] found an optimum temperature of 26³C for luminescence of A. mellea, while Risbeth [11] found that 25³C was the optimum temperature for growth of A. mellea on malt agar. Bermudes et al [4] and Berliner [6] reported the optimum temperature for luminescence of P. stipticus at 22³C and 18^26³C, respectively. Other studies have also found an optimum temperature for growth of basidiomycetes (wood-rotting) between 20 and 30³C [12,13].…”

“…It has previously been noted that temperature a¡ects mycelial growth and luminescence of naturally biolumines-cent fungi [4,6,9,10]. Buller [9] found an optimum temperature between 10 and 25³C and a maximum temperature of 35^37³C for luminescence of P. stipticus.…”

“…Bermudes et al reported that P. stipticus had a bioluminescence optimum of pH 3.8, with poor growth and luminescence below pH 3.6 or above pH 4.4 and no growth or luminescence at pH 6 or above [4]. Kamzolkina [19] found an optimum pH of 4 for luminescence of A. mellea.…”

Structure and non‐enzymatic light emission of two luciferin precursors isolated from the luminous mushroom Panellus stipticus

“…The chemical studies of luminous fungi reported for the past 30 years include: the isolation of fluorescent compounds, i.e. ergosta-4,6,8 ( 14),22-en-3-one and a flavin, which showed a fluorescence emission spectrum identical to the bioluminescence spectrum (4)(5)(6); the partial purification of a fungal luciferin (7); and the investigation of the light emission of crude extracts that apparently required DPNH (8,9). None of these reports dealt with the process and mechanism of light emission beyond speculation.…”