June 1, 1925 
H-ion Concentration and Pigment in Fusana 
1017 
Table VII.— Changes produced on the 
color of the different indicators by the 
reactions of metabolic products of the 
different species of Fusarium on the hy¬ 
drogen-ion concentration of the culture 
media —Continued 
Determinations of the 
changes in the hydro- 
Organism 
~ gen-i 
Days 
of 
growth 
Methyl 
red 
on concentration 
”T _ 
Brom ! Brom 
phenol thymol 
blue blue 
; % 
Ph 
Ph 1 Ph 
. culm or urn 
(W. Smith) 
Sacc. _ 
4 5.0 
|. 
Do_ 
6 _ 
4.0 ! 
Do_ 
8 _ 
4.4 
Do_ 
10 _ 
6 0 
Do 
12 . 
7 0 
. moniliforme 
(Shel.) Shcr_ 
4 5.0 
Do_ 
6. 
4. 6 
Do_ 
8 | 5.6 
Do_ 
10 _ 
6 4 
Do_ 
12 1 _ 
7.4 
r adicicola 
Wr_ 
4 5.0 
Do_ 
6 _ 
4.6 
Do_ 
8_ 
6 0 
Do_ 
10 _ 
6. 8 
Do_ 
12 _ 
7. 4 
. martii Ap. et 
Wr_ 
4 5.0 
Do_ 
6 _ 
4.6 i 
Do_ 
8 _ 
5.8 
Do_ 
10 _ 
_ 6.6 
Do_ 
12 :_ 
_ 7.2 
EXPLANATION OF RESULTS 
The data in Table VII confirms the 
results which were obtained on the 
behavior of Fusarium species in dex¬ 
trose solutions in all the preceding 
studies. It is shown that the differ¬ 
ent organisms increase the hydrogen- 
ion concentration of the culture media 
during the utilization of dextrose and 
decrease it as soon as the supply of this 
substance is completely removed from 
the substratum. 
The movement of the reactions— 
that is, the rapidity with which the 
released hydrogen and hydroxyl ions 
travel in the different parts of the sub¬ 
stratum—is not recorded in Table VII, 
because the area which manifested the 
different changes in the hydrogen-ion 
concentration did not vary in the 
different cultures. The reactions did 
not extend much beyond the area 
which the colony of the different organ¬ 
isms occupied. It may be added that 
the changes in the color of the indi¬ 
cator, produced by the reactions of the 
organism in solid culture media con¬ 
tained in test tubes 18 cm. long and 1.5 
cm. in diameter, did not extend more 
than 2 cm. deep from the surface of the 
colony in the substratum. In cul¬ 
tures, however, older than 20 days the 
changes in the color of the indicator, 
and particularly of brom thymol blue, 
spread throughout the entire culture 
media. This leads to the conclusion 
that both the hydrogen and the hy¬ 
droxyl ions, released in the substratum 
by the reactions of the organism with 
the nutrient substances, do not travel 
fast in solid culture media, because, if 
they did, the reactions of the hydrogen 
ions as well as the changes in the color 
of the indicator would be instantaneous. 
Methyl red was far less sensitive 
than any of the other two indicators. 
It did not change color after the growth 
of the organism, this reaction possibly 
being due to some modification of the 
methyl red molecule by the metabolic 
products of the organism. 
BEHAVIOR OF DIFFUSIBLE PIG¬ 
MENTS IN ACIDS AND ALKALIES 
The object of these studies was to 
explain some of the reactions, pro¬ 
duced in solid media by certain Fu¬ 
sarium species, which tend to induce 
the development of pigment of different 
colors at different hydrogen-ion con¬ 
centrations. 
Diffusible pigments of certain Fusa¬ 
rium species, produced at P H of 4.0 and 
5.0 in dextrose solutions whose initial 
hydrogen-ion concentration was main¬ 
tained constant by the addition of ad¬ 
justing reagents, were treated with 0.1 
normal NaOH. The determinations 
were made with 9 c. c. of the solution 
containing the diffused pigment against 
1 c. c. of the reagent. The changes 
which were produced in the color of the 
pigment are recorded in Table VIII. 
Table VIII.— Changes produced in the original color of the pigment of certain 
Fusarium species by the addition of 0.1 normal NaOH 
Organism 
Initial 
Ph 
Color of pigment before treatment 
Color of pigment after 
treatment 
Fusarium culmorum _ 
5.0 
Victoria lake ____ 
Dusky auricula purple. 
Lilac. 
Matheus purple. 
Light vinaceous purple. 
F. radicicola _ 
4.0 
Scarlet red. . 
F. martii _ 
5.0 
Maroon, dark 
F. malli _ 
5.0 
Cinnamon_ 
