162
ROBINA B. SCHOLES A N D J. M. SHEWAN
allowed to spoil often luminesce and it was subsequently shown that
this was due t o the presence of luminous bacteria. About ten species of
such bacteria are now recognized and belong mainly to the genera
Vibrio and Aeromonas (Spencer, 1966), although the taxonomic
position of some of these is still in doubt. Their physiology and biochemistry, more particularly the mechanism of luminescence has been
the subject of numerous papers, monographs and books (Harvey,
1940, 1967 ; McElroy and Glass, 1961 ; Strehler, 1955). Although the
organisms are facultative anaerobes, they in fact require oxygen for
luminescence and McElroy and Seliger (1962) have postulabd that
bioluminescence originally was an incidental concomitant of chemical
reactions that were most efficient in removing oxygen from living
systems. If, as is generally believed, the earliest form of life on earth
developed in the absence of oxygen, when oxygen did appear it
would have been toxic to these anaerobes and would have had to be
eliminated. Sufficient energy is liberated in this process to excite
organic molecules to emit light.
The extreme sensitivity of bioluminescence to oxygen has been
utilized to detect this element in very low concentrations. Thus,
luminous bacteria can produce measurable light when the oxygen
concentration is as low as 1 part in 100 000 (Harvey and Morrison,
1923). Beijcrinck was the first to utilize these organisms in studies on
photosynthesis (see Harvey, 1940). Using an emulsion of clover leaf
chloroplasts and the bacteria, and allowing the latter to use up all the
oxygen in the dark, Beijerinck then exposed the mixture to lights of
different wavelengths. Only when the colour which causes the decomposition of CO, to 0, was used did luminescence occur. When all
the oxygen so formed was exhausted the mixture once more became
dark and striking a match was sufficient to again produce luminescence
(Harvey, 1940).
The organisms have been used in a variety of other ways-to
measure the diffusion of oxygen through rubber and other substances;
in drug research; to test vacuum efficiency and porosity of filters.
They have also been used to demonstrate that the presence of molecular
oxygen is not necessary for the decomposition of H,O, by catalase
(Johnson and van Schouwenburg, 1939), and in some rather elegant
experiments designed to investigate some of the factors influencing the
growth and development of bacterial colonies on agar plates. These
latter studies appear to show that limitation of growth on agar is more
directly related to nutrients than to the presence of toxic substancee
(Cruickshank, 1934). Extracts of luminous bacteria also promise t o be
useful in assaying various nucleotides (McElroy and Strehler, 1964).
ROBINA B. SCHOLES A N D J. M. SHEWAN
allowed to spoil often luminesce and it was subsequently shown that
this was due t o the presence of luminous bacteria. About ten species of
such bacteria are now recognized and belong mainly to the genera
Vibrio and Aeromonas (Spencer, 1966), although the taxonomic
position of some of these is still in doubt. Their physiology and biochemistry, more particularly the mechanism of luminescence has been
the subject of numerous papers, monographs and books (Harvey,
1940, 1967 ; McElroy and Glass, 1961 ; Strehler, 1955). Although the
organisms are facultative anaerobes, they in fact require oxygen for
luminescence and McElroy and Seliger (1962) have postulabd that
bioluminescence originally was an incidental concomitant of chemical
reactions that were most efficient in removing oxygen from living
systems. If, as is generally believed, the earliest form of life on earth
developed in the absence of oxygen, when oxygen did appear it
would have been toxic to these anaerobes and would have had to be
eliminated. Sufficient energy is liberated in this process to excite
organic molecules to emit light.
The extreme sensitivity of bioluminescence to oxygen has been
utilized to detect this element in very low concentrations. Thus,
luminous bacteria can produce measurable light when the oxygen
concentration is as low as 1 part in 100 000 (Harvey and Morrison,
1923). Beijcrinck was the first to utilize these organisms in studies on
photosynthesis (see Harvey, 1940). Using an emulsion of clover leaf
chloroplasts and the bacteria, and allowing the latter to use up all the
oxygen in the dark, Beijerinck then exposed the mixture to lights of
different wavelengths. Only when the colour which causes the decomposition of CO, to 0, was used did luminescence occur. When all
the oxygen so formed was exhausted the mixture once more became
dark and striking a match was sufficient to again produce luminescence
(Harvey, 1940).
The organisms have been used in a variety of other ways-to
measure the diffusion of oxygen through rubber and other substances;
in drug research; to test vacuum efficiency and porosity of filters.
They have also been used to demonstrate that the presence of molecular
oxygen is not necessary for the decomposition of H,O, by catalase
(Johnson and van Schouwenburg, 1939), and in some rather elegant
experiments designed to investigate some of the factors influencing the
growth and development of bacterial colonies on agar plates. These
latter studies appear to show that limitation of growth on agar is more
directly related to nutrients than to the presence of toxic substancee
(Cruickshank, 1934). Extracts of luminous bacteria also promise t o be
useful in assaying various nucleotides (McElroy and Strehler, 1964).