Archives of
Microbiolngy
Arch. Microbiol.119, 213-214 (1978)
9 by Springer-Verlag 1978
Changes in the Rate of Synthesis of Wall Polysaeeharides during the Cell Cycle of Yeast P. Biely Institute of Chemistry, Slovak Academy of Sciences, 809 33 Bratislava, Czechoslovakia
Abstract. Reevaluation and comparison of seemingly contradictory literature data on the mode of synthesis of wall polysaccharides during the cell cycle of Saccharomyces cerevisiae explained the source of discrepancies and demonstrated their general consonance in the following points: 1. The rate of synthesis of glucan and mannan is not constant and does not increase continuously throughout the entire cell cycle. 2. The rate of synthesis of both polysaccharides is considerably reduced at the time of cell division and in the prebudding phase. Key words: Saccharomyces cerevisiae Glucan - Mannan - Cell cycle.
Cell wall -
cells of a pulse-labeled asynchronous culture of S. cerevisiae. The number of silver grains counted was proportional to the rate of wall synthesis within a time interval equal to duration of the radioactive pulse. In all studies with synchronous Cultures the authors followed the increase of wall polysaccharides as a function of time. The data published by Biely et al. (1973, Table 1), Sierra et al. (1973, Fig.4) and Hayashibe et al. (1977, Fig. 1) were brought by a simple mathematical operation to a common denominator and then compared. Such a comparison pointed to a general consonance of seemingly contradictory results from different laboratories. Plotting the average number of silver grains counted on isolated cell walls of S. cerevisiae labeled with 3H-D-glucose for 15 rain (Biely et al., 1973) versus time
(ancount Further progress in the elucidation of regulation mechanisms involved in the cell wall formation in yeast is strongly dependent on accuracy of data on the mode of cell wall polysaccharide increase during the cell cycle. With the exception of chitin (Cabib and Farka~, 1971), the present data on the mode of increase of wall polysaccharides during the cell cycle of budding yeast are contradictious. Employing a synchronous culture of Saccharomyces cerevisiae Sierra et al. (1973) came to the conclusion that both glucan and mannan are synthesized continuously in an exponential pattern throughout the entire cell cycle. Recent data of Hayashibe et al. (1977), using a similar approach, pointed out however, that the rate of synthesis of mannan and total wall glucan is reduced at the time of cell division. This finding is in agreement with the results of Wiemken et al. (1970) on behaviour o f insoluble glucan and with autoradiographic data from our laboratory (Biely et al., 1973). In this work we counted silver grains on isolated cell walls of individual
~
- fit); t, time
)
corresponding to the
respective cell stage (Fig. 1) shows that the rate of wall synthesis (considered as a sum of glucan and mannan synthesis) decreases during cell division and in the prebudding phase. However, on a summation curve ( ~ graincount ) to 15rain - f ( t ) which corresponds to the pattern of increase of wall polysaccharides in a single growing cell (Fig. 1), the change in the rate of wall synthesis at the time of cell division is reflected only as an inflexion on the curve. This inflexion can be easily overlooked when the mode of polysaccharide increase is followed in synchronously growing cultures. The example below demonstrates that it is more suitable to measure the rates of synthesis of polysaccharides than to follow their mode of increase. The values corresponding to experimentally observed data of Sierra et al. (1973, Fig.4) were used for calculation of average rates of synthesis of glucan and mannan within 15 rain time intervals. Differences be-
0302-8933/78/0119/0213/$ 01.00
214
Arch. Microbiol., Vol. 119 (1978)
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Biely, P., Kova~ik, J., Bauer, S. : Cell wall formation in yeast. An electron microscopic autoradiographic study. Arch. Microbiol. 94, 365-371 (1973) Cabib, E., Farka~, V. : The control of morphogenesis: An enzymatic mechanism for the initiation of septum formation in yeast. Proc. Nat. Acad. Sci. U.S.A. 68, 2052-2056 (1971) Hayashibe, M., Sando, N. : Characterization of different sized cells of baker's yeast. J. Gen. Appl. Microbiol. 16, 15-27 (1970) Hayashibe, M., Abe, N., Matsui, M. : Mode of increase in cell wall polysaccharides in synchronously growing Saeeharomyees cerevisiae. Arch. Microbiol. 114, 9 1 - 9 2 (1977) Sierra, J. M., Sentandreu, R., Villanueva, J. R.: Regulation of wall synthesis during Saccharomyces cerevisiae cell cycle. FEBS Lett. 34, 285-290 (1973) Wiemken, A., Matile, P., Moor, H.: Vacuolar dynamics in synchronously budding yeast. Arch. Mikrobiol. 70, 89 - 103 (1970)
Sierra et al. (1973) presented in this way represent additional evidence that the rate of both glucan and mannan synthesis during the cell cycle is considerably
Received July 10, 1978
I
I
30
60
I 90 Time (min)
I
i
120
150
Fig.2. Rate of glucan (0) and mannan (O) synthesis during the cell cycle of S. cerevisiae calculated from experimental values determined by Sierra et al. (1973). Arrows indicate budding initiation according to the authors
/
Microbiolngy
Arch. Microbiol.119, 213-214 (1978)
9 by Springer-Verlag 1978
Changes in the Rate of Synthesis of Wall Polysaeeharides during the Cell Cycle of Yeast P. Biely Institute of Chemistry, Slovak Academy of Sciences, 809 33 Bratislava, Czechoslovakia
Abstract. Reevaluation and comparison of seemingly contradictory literature data on the mode of synthesis of wall polysaccharides during the cell cycle of Saccharomyces cerevisiae explained the source of discrepancies and demonstrated their general consonance in the following points: 1. The rate of synthesis of glucan and mannan is not constant and does not increase continuously throughout the entire cell cycle. 2. The rate of synthesis of both polysaccharides is considerably reduced at the time of cell division and in the prebudding phase. Key words: Saccharomyces cerevisiae Glucan - Mannan - Cell cycle.
Cell wall -
cells of a pulse-labeled asynchronous culture of S. cerevisiae. The number of silver grains counted was proportional to the rate of wall synthesis within a time interval equal to duration of the radioactive pulse. In all studies with synchronous Cultures the authors followed the increase of wall polysaccharides as a function of time. The data published by Biely et al. (1973, Table 1), Sierra et al. (1973, Fig.4) and Hayashibe et al. (1977, Fig. 1) were brought by a simple mathematical operation to a common denominator and then compared. Such a comparison pointed to a general consonance of seemingly contradictory results from different laboratories. Plotting the average number of silver grains counted on isolated cell walls of S. cerevisiae labeled with 3H-D-glucose for 15 rain (Biely et al., 1973) versus time
(ancount Further progress in the elucidation of regulation mechanisms involved in the cell wall formation in yeast is strongly dependent on accuracy of data on the mode of cell wall polysaccharide increase during the cell cycle. With the exception of chitin (Cabib and Farka~, 1971), the present data on the mode of increase of wall polysaccharides during the cell cycle of budding yeast are contradictious. Employing a synchronous culture of Saccharomyces cerevisiae Sierra et al. (1973) came to the conclusion that both glucan and mannan are synthesized continuously in an exponential pattern throughout the entire cell cycle. Recent data of Hayashibe et al. (1977), using a similar approach, pointed out however, that the rate of synthesis of mannan and total wall glucan is reduced at the time of cell division. This finding is in agreement with the results of Wiemken et al. (1970) on behaviour o f insoluble glucan and with autoradiographic data from our laboratory (Biely et al., 1973). In this work we counted silver grains on isolated cell walls of individual
~
- fit); t, time
)
corresponding to the
respective cell stage (Fig. 1) shows that the rate of wall synthesis (considered as a sum of glucan and mannan synthesis) decreases during cell division and in the prebudding phase. However, on a summation curve ( ~ graincount ) to 15rain - f ( t ) which corresponds to the pattern of increase of wall polysaccharides in a single growing cell (Fig. 1), the change in the rate of wall synthesis at the time of cell division is reflected only as an inflexion on the curve. This inflexion can be easily overlooked when the mode of polysaccharide increase is followed in synchronously growing cultures. The example below demonstrates that it is more suitable to measure the rates of synthesis of polysaccharides than to follow their mode of increase. The values corresponding to experimentally observed data of Sierra et al. (1973, Fig.4) were used for calculation of average rates of synthesis of glucan and mannan within 15 rain time intervals. Differences be-
0302-8933/78/0119/0213/$ 01.00
214
Arch. Microbiol., Vol. 119 (1978)
/
800
150 e-
-?: L~
600 0
100
o o t3~
"~ / tt3
8,
400
/ /
2
5O
/
/
/
/
o"
13"
200
,r
I
!
30
60
I
90 Time [rain)
I
I
120
150
T
E tt~ E
o~ .~
"S References rr
tween two in 15min succeeding values of radio. . / A cpm active counts,~ were plotted versus time LI- 5~miu f(t), Fig. 2). As it can be seen, experimental data of
Biely, P., Kova~ik, J., Bauer, S. : Cell wall formation in yeast. An electron microscopic autoradiographic study. Arch. Microbiol. 94, 365-371 (1973) Cabib, E., Farka~, V. : The control of morphogenesis: An enzymatic mechanism for the initiation of septum formation in yeast. Proc. Nat. Acad. Sci. U.S.A. 68, 2052-2056 (1971) Hayashibe, M., Sando, N. : Characterization of different sized cells of baker's yeast. J. Gen. Appl. Microbiol. 16, 15-27 (1970) Hayashibe, M., Abe, N., Matsui, M. : Mode of increase in cell wall polysaccharides in synchronously growing Saeeharomyees cerevisiae. Arch. Microbiol. 114, 9 1 - 9 2 (1977) Sierra, J. M., Sentandreu, R., Villanueva, J. R.: Regulation of wall synthesis during Saccharomyces cerevisiae cell cycle. FEBS Lett. 34, 285-290 (1973) Wiemken, A., Matile, P., Moor, H.: Vacuolar dynamics in synchronously budding yeast. Arch. Mikrobiol. 70, 89 - 103 (1970)
Sierra et al. (1973) presented in this way represent additional evidence that the rate of both glucan and mannan synthesis during the cell cycle is considerably
Received July 10, 1978
I
I
30
60
I 90 Time (min)
I
i
120
150
Fig.2. Rate of glucan (0) and mannan (O) synthesis during the cell cycle of S. cerevisiae calculated from experimental values determined by Sierra et al. (1973). Arrows indicate budding initiation according to the authors
/
