Growth of Germ Tubes of Erysiphe Spores in Deuterium Oxide

Pratt, Robertson

doi:10.1002/j.1537-2197.1936.tb09005.x

Cited by 11 publications

(5 citation statements)

References 62 publications

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“…As soon as the preparation of heavy water on a larger scale was made possible, its biological effects on living organisms have immediately attracted wide attention of scientists and it happened as early, as before WWII [1][2][3][4]. The first experiments were cautiously planned with small organisms (such, as algae, plants, fungi and bacteria), to stepwise switch toward the more complex and warm-blooded ones.…”

Section: Introductionmentioning

confidence: 99%

“…For example, Lewis was the first one to publish his results on full inhibition of the tobacco seeds germination in pure heavy water and on considerable retardation of this process by 50% D 2 O only [1]. Pratt was another pioneer of the experiments with heavy water who investigated its strong inhibitory effect on growth of fungus Erysiphe graminis tritici [2]. Further systematic investigations have been carried out with selected mammals (e.g., [5][6][7][8]) and more recent studies with heavy water often target various different tissue preparations, with an aim to reveal apoptotic potential of D 2 O against the lung, pancreatic and other tumor cells [9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

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Impact of D2O on the peptidization of L-alanine

Fulczyk

Łata

Talik

et al. 2020

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This is our fifth consecutive study carried out in an order to collect experimental evidence on the impact of heavy water (D 2 O) on the spontaneous peptidization of proteinogenic α-amino acids and this time its subject matter is L-alanine (L-Ala). Our four earlier studies have been focused on the two sulfur-containing α-amino acids (i.e., L-cysteine (L-Cys) and L-methionine (L-Met)), and on two structurally related α-amino acids (i.e., L-proline (L-Pro) and L-hydroxyproline (L-Hyp)). It seemed interesting to assess the effect exerted by D 2 O on L-Ala, the simplest chiral (endogenous and proteinogenic) α-amino acid with as low molar weight, as 89.09 g mol −1 only. As analytical techniques, we used high-performance liquid chromatography with the diode array detection (HPLC-DAD), mass spectrometry (MS), and scanning electron microscopy (SEM). The obtained results make it clear that the impact of heavy water on the dynamics of the spontaneous peptidization of L-Ala is even stronger than with the four other α-amino acids discussed earlier (although in all five cases, heavy water significantly hampers spontaneous oscillatory peptidization). Unlike in the four previous cases, though, the solubility of L-Ala in pure D 2 O is quite low and it takes twice as much time to dissolve it in D 2 O than in MeOH + X, 70:30 (v/v). Consequently, the peptidization of L-Ala in heavy water is even more obstructed than it was the case with the other investigated α-amino acids and it results in considerable yields of the L-Ala crystals (most probably at least partially deuterated) at the expense of the L-Ala-derived peptides. Perhaps it might be interesting to add that out of five α-amino acids investigated so far, which can be divided into two groups of endogenous and exogenous species, two endogenous species (L-Cys and L-Pro) undergo spontaneous oscillatory peptidization in an aqueousorganic solvent (i.e., in the absence of D 2 O) following the circadian rhythm, whereas two exogenous ones (i.e., L-Met and L-Hyp) do not. The third endogenous species (L-Ala) first undergoes two initials oscillations which are damped (not periodic) and the oscillatory changes are on a scale of ca. 10 h (as estimated with use of the Fourier transform approach) and after that, the system reaches a steady state.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impact of D2O on the peptidization of L-alanine

Fulczyk

Łata

Talik

et al. 2020

Reac Kinet Mech Cat

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“…Since the points describe sigmoid curves, it seemed of interest to examine the data to ascertain whether they could be represented by the equation characteristic of autocatalyzed monomolecular reactions that has been found, in many cases, to describe reasonably well the growth of populations and of individual organisms (Ostwald, 1905;Robertson, 1908aRobertson, , 1905bRobertson, , 1923Reed and Holland, 1919;Reed, 1920Reed, , 1921aReed, , 1921bReed, , 1925aReed, , 1925bReed, , 1932Gaines and Nevens, 1925;Porterfield, 1928;Pratt, 1936).…”

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Influence of the Size of the Inoculum on the Growth of Chlorella vulgaris in Freshly Prepared Culture Medium

Pratt

1940

American Journal of Botany

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THE IMPORTANCE of the unicellular green alga, Chlorella vulgaris, to plant physiologists engaged in studies of cellular metabolism and especially of photosynthesis is well known. Relatively few detailed studies have been made of its growth, however. The present paper deals with the growth curve of Chlorella in cultures inoculated with different numbers of cells taken from parent cultures of the same age. Multiplication, or increase in cell number, was used as an index of growth in this work, although it is realized that a period of cell enlargement precedes each division, and that growth is the result of these two processes.MATERIALS AND METHoDs.-Cells for the experiments were withdrawn from four-day-old, rapidly growing stock suspensions of Chlorella vulgaris cultured as previously described (Craig and Trelease, 1937; Pratt and Trelease, 1935) in a solution that contained KN0 3 , 0.025M; MgS0 4 "7H 20, 0.02M; KH 2P04, O.OISM; FeS04"7H20, O.OOOOIM; potassium citrate, O.OOOOIM; and Zn, Cu, B, and Mn in approximately the concentrations employed by Trelease and Trelease (1935). The initial pH of this solution was 4.45. New stock cultures were started daily so that there was always available a supply of cells of approximately the same physiological age and activity.Cells were separated from the culture medium and were washed in three changes of distilled water by repeated centrifugation and decantation. They were then suspended in distilled water and the density of the population in the suspension was estimated from haemacytometer counts. Inocula containing the desired number of cells were pipetted into 500 ml. Pyrex glass Florence flasks, each of which contained 150 ml, of the standard nutrient solution. The flasks were continuously illuminated from below by a water-cooled battery of twentyfour 50-watt frosted Mazda lamps. The light intensity, measured by means of a Weston photoelectric-celllight meter, Model 603, varied from 21,000 lux to IS,OOO lux. The lamps were replaced by a complete new set when the intensity fell below this value. The temperature at the level of the flasks varied from ISo to 22°C.A gas mixture containing 5 per cent CO 2 and 95 per cent air was bubbled continuously through the solutions. The cultures were shaken vigorously twice daily to insure separation and uniform suspension of the cells.Growth measurements were made periodically by withdrawing small samples from each flask and estimating the cell population from haemacytometer counts. Triplicates of each culture were prepared, 1 Received for publication November 97, 1939. The author is indebted to Miss Jane Fong for valuable assistance in the laboratory. 52and cell counts were based on the averages of haemacytometer counts of four different samples from each flask. Each point in the figures represents, therefore, the average of twelve samples. The maximum deviation from the mean value occurred in the lower portions of the growth curves and never exceeded 5 per cent. Over the major portion of the curves in all cultures the deviation of ind...

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“…long. The conidial germ tubes of Erysiphe graminis tritici, the fungus that produces the powdery mildew disease of wheat, are well suited to quantitative studies of the influence of D 20 on growth, and in an earlier report (Pratt, 1936) it was shown that the deleterious action of 100 per cent D 20 on germ tubes is more pronounced after germination has begun in H 20. The object of the present study was to determine the effect of exposure to H 20 for different lengths of time on the subsequent growth of Erysiphe germ tubes, when they were transferred to solutions containing D"O and H 20 in different proportions.…”

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confidence: 99%

“…METHoDs.-Preparqtion of D 2 0 and H 2 0 . -T h e D 20 used in these experiments was prepared in the Department of Chemistry of Columbia University by the method described by Brown and Daggett (1935), and was purified in our laboratory as in previous experiments (Pratt, 1936). The control water was ordinary distilled H 20, buffered at pH 7.2 (determined with a La Motte comparator accurate to ± 0.1 pH unit) by means of suitable proportions of K 2HPO.…”

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confidence: 99%