In the previous papers
l, 2, 3), characteristics of the softening spoilage of fish sausage, species of causative bacteria with reference to its activity of decomposing starch under anaerobic condition have been reported. In addition, the use
4) of a mixture of three different compounds, including sodium pyrophosphate, sorbic aicd and glucose was suggested to be effective as apreventive means of this particular spoilage.
This time, the nature of sodium pyrophosphate relevant to the retardation of growth in the spoilage bacteria will be discussed.
W. Vishniac (1950)
18), and separately G. Dirheimer (1956)
19), already pointed out an inhibitory effect of pyrophosphate or tripolyphosphate on yeast hexokinase. They noticed that some chelating action of these polyphosphates with magnesium ion would cause the inhibition of hexokinase, which then can be restored by addition of MgSO
4 or adenosinetriphosphate.
Halvorson (1957)
5) stated that certain bacterial spores will be able to make process of glucose metabolism without E. M. P. glycolytic cycle. After the germination take plack, however, phosphorylation reatcion
22) should be necessary for normal growth and propagation of their vegetative cells. It is probably valid from Treadwell's experiment (1958), in which headded one of the following sodium azide, monoiodoacetic acid and dinitrophenol to the spore culture and found a marked retardation in growth phase of vegetative cells after the germination had completed.
A similar line of the research is just our primary concern about
Bacillus circulans how the different stage of its growth is really inhibited by the presence of sodium pyrophosphate and sorbic acid.
By a test for the culture of
Bacillus circulans in a medium containing pepton, glucose, sodium chloride, and sodium pyrophosphate (0.4 per cent), it showed a more restricted consumption of glucose accompanied by a samll change in pH value throughout the cultiion than the culture in which the polyphosphate was entirely absent.
A nepherometric observation was carried out of the whole progress of growth, covering germination, outgrowth and cell division of the microorganism, with a culture medium, to which L-alanine (6mM), adenosine (12 μM), sodium pyrophosphate (0.4%) and sorbic acid (0.1%) were incorporated. As shown in Fig. 3 and 4, the pyrophosphate not looks like to affect on germination but on the growth phase afterward. Also it is clear in a series of photomicrograph of Plate 1, vegetative cells in chain form can scarcely be seen even after 24 hours' incubation, while in a control run, many rod-shaped forms in chain are found in a sample of 9 and 24 hours'. The presence of sodium azide or monoindoacetic acid can give a similar pattern of growth (Plate 2 and 3). Also electronmicrographs from Plate 5, 6 and 7 would show a moredetailed picture of each growth phase. In the culture containing sodium pyrophosphate, certain number of spore indicate translucnt area in spore and others are partly broken after a few hour's cultivation and small number of vegetative form only develops in 24 hours' culture.
From the foregoing findings, sodium pyrophosphate and sorbic acid seem to play a main part of inhibition on both growth phase and cell division rather than on germination of the spores of
Bacillus circulans.
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