Introduction. - It is known that certain bacteria are inhibited in their growth by the presence of sulfanilamide or related compounds in the nutrient medium, and it has been suggested by Fildes(1) and by Woods(2) that this inhibition is due to specific interference with the utilization of essential metabolites, in particular p-amino benzoic acid. In the present paper data will be presented which show that the growth of isolated tomato roots(3) is inhibited in the presence of appropriate concentrations of sulfanilamide or its derivatives, but that this growth inhibition can be in whole or in part abolished by the further presence of p-amino benzoic acid, a substance not otherwise essential as a supplement for the growth of isolated tomato roots

Bonner, James

English

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BOTANY: J. BONNER
A REVERSIBLE GROWTH INHIBITION OF ISOLATED TOMA TO
ROOTS*
By JAMES BONNER
WILLIAM G. KERCKHOFF LABORATORIES, CALIFORNIA INSTITUTE OF TECHNOLOGY
Communicated June 17, 1942
Introduction.-It is known that certain bacteria are inhibited in their
growth by the presence of sulfanilamide or related compounds in the nutri-
ent medium, and it has been suggested by Fildes' and by Woods2 that this
inhibition is due to specific interference with the utilization of essential
metabolites, in particular p-amino benzoic acid. In the present paper data
will be presented which show that the growth of isolated tomato roots3 is
inhibited in the presence of appropriate concentrations of sulfanilamide or
its derivatives, but that this giowth inhibition can be in whole or in part
abolished by the further presence of p-amino benzoic acid, a substance not
otherwise essential as a supplement for the growth of isolated tomato roots.
Methods.-Isolated tomato roots were cultured aseptically in the nutrient
medium described earlier.4 One centimeter tips from vigorously growing
branch roots were used as inocula for the experimental cultures. Ap-
proximately 200 roots were grown in each experiment. The two hundred
initial tips were randomly divided into 10 lots of 20 tips each and each
treatment carried out on one or more lots. The conclusions contained in
this paper are based on a series of 42 such experiments.
All cultures were maintained in Petri dishes, four roots per dish, in the
dark at 25°C. for one week. At the end of this time the growth in length
of the principal axis of each root was measured. The roots were then dis-
carded and fresh inocula from stock cultures used in further experiments.
Three clones of roots, all of the variety "San Jose Canner"5 were used.
These clones, each of which had previously been subjected to 27 weekly
transfers in the standard basal medium, reacted similarly to all of the treat-
ments discussed below.
Experimental Results.-Table 1 shows that the growth of isolated tomato
roots is inhibited by sulfanilamide and by sulfapyridine. In the presence
of 30 mg. per liter of either of these substances isolated tomato roots grew
only 15-21% as long in one week as similar roots not receiving inhibitor.
Table 1 also shows that the growth inhibition caused by sulfanilamide or
sulfapyridine is in part offset by the further addition of p-amino benzoic
acid to the culture medium in the concentration of 1 mg. per liter. Roots
receiving inhibitor and p-amino benzoic acid grew 3.3 to 4.5 times as much
in one week as roots receiving inhibitor only. This effect cannot be as-
scribed to a general growth-promoting effect of p-amino benzoic acid,
since, as shown in table 2, this substance in the concentration of 1 mg. per
VOL. 28, 1942 321
BOTANY: J. BONNER
liter is without effect on the growth of tomato roots. Increased (10 times)
concentrations of nicotinic acid or pyridoxine did not affect the inhibition as
did p-amino benzoic acid.
TABLE 1
THE EFFECT OF SULFANILAMIDE AND SULFAPYRIDINE ON THE GROWTH OF ISOLATED
TOMATO ROOTS. GROWTH IN MM. PER ROOT PER WEEK
SULFONILA- SULFAPYRI-
MIDE NO. OF DINE NO. OF
SUPPLEMENTS EXPTS. ROOTS MM./WEBEK EXPTS. ROOTS MM./WEEK
None I-25 40 56.6 2.2 I-24 38 45.0 2.5
I-31 26 49.8 3.1 I-32 32 52.7 1.6
30 mg. inhibitor/I. 1-25 33 12.0 1.5 I-24 29 9.7 1.3
I-31 14 10.0 1.3 I-32 30 7.8 0.6
30 mg. inhibitor/I. I-25 19 39.5 3.4 1-24 17 37.9 2.5
1 mg. p-amino benzoiC
acid/I. I-31 16 36.2 2.3 1-32 14 35.4 1.4
TABLE 2
LACK OF EFFECT OF p-AMINO BENZOIc ACID ON THE GROWTH OF ISOLATED TOMATO
ROOTS. GROWTH IN MM. PER ROOT PER WEEK
NO p-AMINO BENZOIC ACID 1.0 MG./L. P-AMINO BENZOIC ACID
NO. OF NO. OF
EXPTS. ROOTS LENGTH ROOTS LENGTH
I-27 18 52.2 4.3 18 53.6 3.5
1-31 26 49.8 3.1 16 49.1 3.5
I-37 13 42.7 1.8 17 41.8 1.3
Sulfathiazole also inhibits the growth of isolated tomato roots as is
shown in table 3, which gives the composite results of 16 experiments.
Since the growth of untreated con-trol roots varied from one experiment to
the next (as in tables 1 and 2) the growth rates in each experiment were
reduced to per cent of the untreated control growth rate and it is this rela-
tive growth rate which appears in table 3. It is clear from this table that
TABLE 3
INHIBITION OF THE GROWTH OF ISOLATED TOMATO ROOTS BY SULFATHIAZOLE AND
ITS REVERSAL BY p-AMINO BENZOIC ACID. MEAN VALUES FROM 16 EXPERIMENTS.
GROWTH RATES IN PER CENT OF CONTROL ROOTS GROWN FOR 1 WEEK IN STANDARD
BASAL MEDIUM. THE AVERAGE GROWTH RATE (100%) OF THE CONTROL ROOTS WAS
45.8 = 2.33 MM. PER WEEK IN THESE EXPERIMENTS
SULPATHIAZOLB p-AINO BENZOIC ACID CONCENTRATION; MG./L.
CONC.; MG./L. GROWTH PBR WEBK: % OF UNTREATED CONTROLS
0 0.03 0.10 0.30 1.0
100 3 ... ... ... 27.5
30 15.2 17.0 21.0 25.0 53.6
10 18.4 20.0 32.3 58.7 94.6
3 37.4 52.2 83.0 99.0 100.7
1 67.6 92.3 97.7 99.0
0 100 ... ... ... 100
322 PROC. N. A. S.
BOTANY: J. BONNER
sulfathiazole is a relatively potent inhibitor of root growth since half inhi-
bition is given by about 2 mg. sulfathiazole per liter. The amount of p-
amino benzoic acid needed to abolish a fixed amount of inhibition varies
with the inhibitor concentration. Thus nearly the same absolute increase
in growth rate was brought about by 0.03 mg. per liter of the material in
the presence of 1 mg. per liter of sulfathiazole as was brought about by 1
mg. per liter of p-amino benzoic acid in the presence of 100 mg. per liter
of sulfathiazole. Inhibition by a given quantity of sulfathiazole was
markedly decreased by the addition of a 100 times smaller quantity of p-
amino benzoic acid in every case. Inhibition by sulfathiazole and reversal
of this inhibition by p-amino benzoic acid would seem to depend in part
on the ratio between the two substances in the nutrient medium rather
than strictly on the absolute amount of inhibitor present.
Isolated tomato roots of the clones used in these experiments appear,
qualitatively, to contain p-amino benzoic acid or related substance of simi-
lar physiological activity,6 even when grown through 40 or more successive
weekly transfers in p-amino benzoic acid free medium. The presence of
this material in such roots suggests that isolated tomato roots of the pres-
ent clones may synthesize the substance.
Discussion.-The inhibition of the growth of isolated tomato roots by
sulfathiazole depends in part on the ratio between added inhibitor and
added p-amino benzoic acid. This observation might suggest that the
inhibition is in part competitive in the sense that sulfathiazole may com-
pete with p-amino benzoic acid for some essential position or function in the
living cell. That sulfathiazole inhibits the growth of roots not supplied
with p-amino benzoic acid is not in disagreement with this view since
isolated tomato roots appear to normally contain this substance. Other
factors may also govern the inhibition.7
Summary.-Isolated tomato roots of 3 different clones were found to be
inhibited in growth by the addition of sulfanilamide, sulfapyridine or sulfa-
thiazole, to the nutrient medium. This inhibition was in whole or in part
abolished by the further addition of p-amino benzoic acid to the medium.
Isolated tomato roots of the clones used normally contain p-amino benzoic
acid, or a substance having similar physiological activity.
* Report of work done with the cooperation of the Work Projects Administration,
0. P. No. 165-1-07-172. This work was made possible in part by the support of Merck
and Company.
1 Fildes, P., British Jour. Expt. Path., 21, 67 (1940).
2 Woods, D. D., Ibid., 21, 74 (1940).
3 White, P. R., Plant Physiology, 9, 585 (1934). Robbins, W. J., and Bartley, Mary,
Science, 85, 246 (1937).
4 Bonner, J., Amer. Jour. Bot., 27, 692 (1940). This medium contains per liter of re-
distilled water: 1.5 mg. ferric tartrate, 20 mg. KH2PO4, 65 mg. KCl, 81 mg. KNO3,
36 mg. MgSO4'7H20, 236 mg. Ca(N03)2-4H20, and 20 gm. sucrose.
VOL. 28, 1942 323
MATHEMA TICS: H. S. VANDIVER
I The seed used was kindly supplied by the California Packing Corporation.
6 The assays for p-amino benzoic acid were carried out by Prof. G. W. Beadle and Prof.
E. Tatum, Stanford University, using a mutant of Neurospora crassa for which p-amino
benzoic acid is an essential supplement.
7In 5. experiments sulfanilamide or its derivatives were applied to intact tomato
plants grown in the greenhouse in sand or solution culture. Concentrations of up to 125
mg. per liter of nutrient were found to be without marked inhibiting effect on root or top
growth.
GENERAL CONGRUENCES INVOLVING THE BERNOULLI
NUMBERS
By H. S. VANDIVER
DEPARTMENT OF PURE MATHEMATICS, THE UNIVERSITY OF TEXAS
Communicated May 29, 1942
Kummer' gave a result which may be expressed as follows:
h -1(h 1))i=o (mod pi), (n - 1 i; n 0 (mod p-1)), (1)
where p is an odd prime; the left-hand member is expanded in full, then
b1/t is substituted for ht, and the b's are defined by the recursion formula
(b + 1)In = bn, (n > 1),
-in which we expand the left-hand member by the binomial theorem and
substitute bk for bk. The latter formula gives the Bernoulli numbers. The
congruences (1) have played an important part in the development of the
arithmetic theory of these numbers.
In the present paper we shall employ the theorem which the writer gave
in another paper,2 the statement of which, for convenience, is repeated here:
THEOREM I. Let R be the ring of algebraic integers in an algebraic field
and put
fni (i01)( a2, * * a*.°ki) = E ariars i (2)
r-1
where the a's and a's are in R and the n's are rational integers _ 0. Further
let there be a rational integer d > 0 such that for all r's in the range 1 to ki and
all i's in the range 1 to s,
arid 1 (mod m) (3)
where m is a fixed ideal in R. Also, let
31 + 32 + * ** + (mod m)
324 PROC. N. A. S.


A reversible growth inhibition of isolated tomato roots

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A reversible growth inhibition of isolated tomato roots

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