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Contributions to mechanism of chemotactic response in Paramecium caudatum
CONTRIBUTIONS TO MECHANISM OF CHEMOTACTIC RESPONSE IN
Paramecium caudatum BY S. DRYL Department of Biology, Nencki Institute of Experimenlal Biology, Warsaw Introduction
sea-urchin spermatozoa and by Harris (1953) for recording the locomotion of granulocytes. Instead of time-exposure a stroboscopic photomicrography method was used by Wingo & Browning (1951) for registering the movement and measuring the swimming rate of Tetrahymena. All the photomicrographic techniques mentioned above have the disadvantage of being limited to somewhat small areas of observation and thus giving no chance of carrying out more extensive studies on the locomotion of large-sized and relatively fast swimming Infusoria such as Paramecium, Stentor and many others. However, more recently Ferguson (1957) developed the horizontal and Dryl (1.958) the vertical arrangement for the photomacrographic recording of the movement of Infusoria. Both techniques render possible the simultaneous registration in a relatively wide area of observation of paths covered by hundreds or even thousands of animals. The studies now reported were made in an attempt to adapt the photomacrographic technique used in recording the movement of Infusoria for studies of the behaviour of Paramecium and (2) to verify the objections advanced by some authors against the avoiding reaction as being the sole factor causing the chemotactic response in Paramecium caudatum.
Motor response of Protozoa to chemical and many other stimuli was the subject of an exhaustive study by Jennings (1905). He found that Paramecia responded to chemotactic stimuli by means of a so-called "avoiding reaction" which, if fully expressed, was characterized by the following three stages: (1) backward swimming due to ciliary reversal, (2) turning to the aboral side and (3) swimming forward again at a new angle. Under certain conditions the animal may respond with a weak avoiding reaction, i.e. showing no backward swimming and merely swinging its anterior end in a small circle. The avoiding reaction appears on the boundary between two solutions of different chemotactic properties. In the case of positive chemotactic stimuli Paramecia swim into the tested solution without any response, showing the avoiding reaction upon leaving it. Consequently negative chemotaxis takes place when the animals show the avoiding reaction on the boundary between the surrounding medium and the solution under study. This mechanism of chemotactic reaction described by Jennings has been generally accepted by other authors, although with some exceptions. Alverdes (1922) expressed the view that Paramecia may respond to chemical stimuli by means of motor response other than that bf the avoiding reaction, e.g. by swimming along arc-lines, by adoral instead ofaboral turnings, etc. Similar objections to Jennings' avoiding reaction were stated by Parducz (1956a, 1956b). In studies of the behaviour of Infusoria the movement of animals has usually been recorded by means of hand drawings made from microscopic observations (Chase & Glaser, 1930; Dembowski, 1922). An entirely new device for recording the locomotion of Protozoa was developed by Gebauer (1930): In conditions of dark-ground illumination he used time-exposure photomicrography for recording the galvanotactic response in Polytoma uvella. A similar technique was introduced by Rothschild & Swann (1949) for recording the locomotion of
Materials and Methods
The experiments were made with a strain of Paramecium caudatum isolated in 1955 near Warsaw and subsequently grown in a mass culture on standard lettuce infusion inoculated with Aerobacter aerogenes (Sonneborn, 1950). One day before the experiment was begun a dense culture of Paramecium was diluted in the proportion of 1:2 with citrate-phosphate buffer solution prepared according to the formula given by the author (Dryl, 1959a): sodium citrate 0.1M.20 ml., sodium phosphate monobasic 0.1 M. 10 ml., sodium phosphate dibasic 0-1 M. 10 ml., redistilled water 945 ml. and CaC12 0.1 M. 15 ml. (Dryl, 1959a). In order to 393
394
ANIMAL
BEHAVIOUR,
avoid precipitation the CaC12 was the last reagent added during preparation of the solution of calcium salts. This solution proved to be not toxic for Paramecium aurelia and Paramecium caudatum. Buffer solutions of pH 5-63, 7.60 and 8-35 were prepared by varying the proportions of mono- and di-basic sodium phosphate. NaC1, KC1, CaC12 and MgC12 solutions were prepared by diluting the chemicals with the citrate-phosphate buffer solution of pH 7.60. (For long lasting series of experiments it is recommended that the buffer solutions should be kept in sterile conditions and to place them in an ice-box before using them in tests.) The determinations of pH were carried out with the aid of a Cambridge Instrument Company Potentiometer having an accuracy of up to 0.01 pH. The methods used for washing and collecting Paramecia have been fully described elsewhere (Dryl, 1961a). In the present series of experiments the movement of Paramecia was recorded using a modification (Dryl, 1961) of the photomacrographic technique described by Dryl (1958) with some improvements as indicated in a recent study (Dryl, 1961b). Beams of light from two projectors were directed through heat-filters from below and obliquely to the surface of a glassplate and also obliquely to the camera optic axis. In this way a dark-ground illumination was obtained. A reflex type camera suitably adapted for taking photomacrographs was fixed vertically above the glass plate in a stand which made possible the regulation of the distance between the camera lens and the subject under observation. A dark-room electric timer was used for regulating the length of the exposure time. All the experiments were performed in the dark-room. When all the preliminary arrangements were made, a glass plate 10 by 15 cm. with a rough margin 1 cm. wide was placed horizontally on the stage as shown on Fig. 1. Six or seven ml. of buffer solution ("the surrounding medium") was spread uniformly over the surface of the glass plate until it reached the margin. The layer of solution covering the glass plate was of approximate thickness 0.5-0.6 him. The effect of evaporation during the relatively short period of testing was found to be negligible. All the tests were performed at a temperature of 18 + 1°C. At each of the four corners of the glass plate 2-3 drops of medium containing dense colonies of Paramecia were placed using
XI,
2-3
a micropipette and then 8 to 10 drops of the test solution was pipetted into the middle area of the plate. Paramecia swim actively into the '"surrounding medium" and after 1 to 2 minutes the animals are seen to be uniformly dispersed in it. During tile course of experiment Paramecia look like small, bright dots moving quickly on the dark background. The chemotactie effect appears on the boundary between the surrounding and tested medium and the motor response of Infusoria is recorded by taking 5- or 10seconds time-exposure photographs. The direction of movement of Paramecia was marked by rapid opening of the lens-diaphragm of the camera during the last 0.5 second of exposure. This operation multiplies the amount of light admitted into the camera and makes the final selection of the recorded path covered by Infusoria appear on the negative to be of greater thickness than that of the preceding section. The photographic equipment necessary for recording the movement of Infusoria is shown on Fig. 1. Results and Discussion In buffer solutions Paramecia swam along spiral lines without turnings. The avoiding reaction appeared as soon as the animals approached the negative chemotactic medium and it was recorded on the negative as an irregular zigzag line. It is known that Paramecium shows a positive chemotactic response to a weakly acid medium with an optimum pH range 5.2-6-2, this having been previously demonstrated by the author (Dryl, 1959b). Positive reaction to the optimum pH is shown on Fig. 2. Paramecia were placed in a buffer solution of pH 8.35. The animals swam into the tested solution ofpH 5.63 without any reaction, yet they showed the avoiding reaction at each contact with the surrounding medium which they had just left. A typical response by a single amimal is shown on Fig. 3. Analysing the path covered by this Infusorian during 45 seconds, it is easy to see that the animal responded in a different manner to each successive contact with the negative chemotactic stimulus in the surrounding medium. Nevertheless, even in this case, all the negative motor response could be recognized as the avoiding reaction according to the definition given by Jennings. The negative chemotactic response of Paramecia placed in a buffer solution of pH 5.63 to a weakly alkaline medium (pH 8.35) is demonstrated in Fig. 4. In this case the animals showed
DRYL: CONTRIBUTIONS TO MECHANISM OF CHEMOTACTIC RESPONSE IN Paramecium eaudatum an avoiding reaction at each contact with the negative chemotactic stimulus in the tested medium. It was proved that Paramecia show more or less typical avoiding reactions towards strong negative chemotactic concentrations (40 raM.) of NaC1, CaC12 and M g C I 2. However, an entirely different motor response was observed when 40 mM. KC1 solution was applied as a chemotactic stimulus. It was found by observation as means of a low power dissection microscope that in this case, instead of turnings typical of avoiding reaction, a peculiar disturbance of movement appeared on the boundary of KC1 solution, namely rotation around the transverse axis of the body. This kind of motor response lasted 4 to 5 seconds and sometimes longer, and in consequence the forward movement of Paramecia nearly ceased at the boundary of the KC1 solution. This phenomenon was registered on the negative as large irregular spots (Fig. 5). In a recent study (Dryl, 1961a) a remarkable slackening of the forward movement of Param e c i u m caudatum was noticed in negative chemotactic threshold concentrations of NaC1, KC1, BaC12 and quinine solutions whereas in CaC12 and MgC12 solutions no significant change of swimming rate in relation to control was observed. The results achieved in another series of experiments indicated a close relationship between the optimum p H for chemotaxis and the p H range of highest swimming rate in Paramecium (Dryl, 1961b). All these findings and the main contribution from the present work provide additional evidence that when ehemotaxis of Paramecium is investigated by more accurate methods, both from qualitative and quantitative points of view, it appears to be a more complicated phenomenon than it was previously believed to be. Further work on these lines might yield valuable information about the mechanism of chemotactic response in Infusoria. All findings described in this section were confirmed by direct observations from the low power dissecting microscope and were partially recorded on a 16 mm. cinematographic film.
Summary The mechanism of the chemotactic reaction of P a r a c e m i u m caudatum was analysed using the time-exposure photomacrographic technique for recording the movement of Infusoria. Paramecia showed a more or less typical Jennings "avoiding reaction" towards p H
395
changes of the medium and to many other chemotactic stimuli, such as NaC1, CaC12, MgC12. Nevertheless, in a 40 mM. KC1 solution the animals; instead of taking avoiding action, showed a peculiar m o t o r response which lasted 4 to 5 seconds and sometimes longer and consisted mainly of rotations around the transverse axis of the body. It is emphasized that both the kind and the duration of m o t o r response to 40 raM. KC1 solution are in strong contradiction to the generally accepted view that avoiding reaction is the only m o t o r response of Paramecia to a chemotactic stimulus in the medium.
REFERENCES Alverdes, F. (1922). Zur Lehre yon den Reaktionen der Organismen auf atissere Reize. Biol. Zentrbl., 42, 218-222. Chase, A. M. & Glaser, O. (1930). Forward movement of paramecium as a function of hydrogen ion concentration. J. Gen. Physiol., 13, 627-636. Dembowski, J. (1922). Untersuchungen iiber die Bewegung yon Paramecium caudatum in Tropfen verschiedener geometrischen Gestalt. Tray. Inst. Nencki., 1, nr. 8, 1-32. Dryl, S. (1958). Photographic registration of movement of protoxoa. Bull. Ac. Polon. Sci. Ser. Sci. Biol., 6, 429-430. Dryl, S. (1959a). Antigenic transformation in Paramecium aurelia after homologous antiserum treatment during autogamy and conjugation. J. Protozool. 6, suppl., abstr., nr. 96. Dryl, S. (1959b). Effects of adaptation to environment on chemotaxis of Paramecium caudatum. Acta. Biol. Exp., 19, 83-93. Dryl, S. (1961a). Chemotaxis in Paramecium caudatum as adaptive response of organism to its environment. Acta Biol. Exp., 21, in press. Dryl, S. (1961b). The velocity of the forward movement of Paramecium caudatum in relation to pH of medium. Bull. Ac. Polon. Sci., Ser. Sci. Biol. 9 in press. Fergusson, M. L. (1957). Photographic technique for quantitative studies of paramecia and other motile cells. Physiol. Zool., 30, 208-215. Gebauer, H. (1930). Zur Kenntnis der Galvanotaxis yon Polytoma uvella und einigen anderen Volovocineen. Beitr. Biol. Pfl, 18, 463-500. Harris, H. (1953). Chemota×is of granulocytes. J. Path. Bact., 66, 135-146. Jennings, H. S. (1905). Das Verhalten der Niederen Organismen unter natiirlichen und experimentellen Bedingungen. Leipzig. Parducz, B. (1956a). Reizp.hysiologischeUntersuchungen an Ziliaten. IV. Uber das Empfindungs---bzw. Reaktions-vermOgen yon Paramecium. Acta Biol. Ae. Sci. Hung., 6, 289-316. Parducz, B. (1956b). Reizphysiologische Untersuchungen an Ziliaten. V. Zum physiologischen Mechanismus der sog. Fluchtreaktion und der Raumorientierung. Aeta Biol, Ac, Sci. Hung., 7, 73-99,
DRYL: CONTRIBUTIONS TO MECHANISM OF CHEMOTACTIC RESPONSE IN Paramecium eaudatum PLATE
IX
Fig. 1. The photographic equipment for recording the movement of Infusoria: c--camera, g--glass plate 10, by 15 cm. covered with solution containing Paramecia p--projector, h--heat-filter, e--electric timer.
Fig. 2. Positive chemotactic response of Paramecia to the buffer solution of pH 5.6. The pH of surrounding medium 8.35. Exposure time--10 seconds.
Atom. Behav.~ 11, 2-3
396
ANIMAL
BEHAVIOUR,
Rothschild, Lord &Swann, M. M. (1949). The fertilization reaction in the sea-urchin egg. A propagated response to sperm attachment. J. exp. Biol., 26, 164-176. Sonneborn, T. M. (t950). Methods in general biology, and genetics of Paramecium aurelia. J. exp. ZooL 113, 87-147.
XI,
2-3
Wingo, W. J. & Browning, J. (1951). Measurement of swimming speed of Tetrahymena geleii by stroboscopic photomicrography. J. exp. Zool., 117, 441-449. (Accepted for publication 5th November, 1962; Ms. number: 213).
ANIMAL
BEHAVIOUR, PLATE
XI,
2-3
X
Fig. 3. Positive chemotactic response of single Paramecium to the buffer solution of pH 5.6. The pH of surroinding medium 8.15. Exposure time--45 seconds.
Fig, 4. Negative chemotactic response of Paramecia to the buffer solution of pH 8' 35. The pH of surrounding medium 5-6. The typical avoiding reactions/turnings/recorded on the boundary of alkaline medium. Exposure time--10 seconds: Scale:the same as on Fig. 2.
Fig. 5. Motor response of Paramecia towards 40 ml. KC1 solution. The KC1 solution diluted with the same citratephosphate buffer solution (pH 7-6) which is present in the surrounding medium. On the left: A peculiar motor response on the boundary of KC1 solution recorded as the white irregular spots. On the right: Paramecia approaching the boundary of KC1 solution. Exposure time--15 seconds. Scale: the same as on Fig. 2.
Paramecium caudatum BY S. DRYL Department of Biology, Nencki Institute of Experimenlal Biology, Warsaw Introduction
sea-urchin spermatozoa and by Harris (1953) for recording the locomotion of granulocytes. Instead of time-exposure a stroboscopic photomicrography method was used by Wingo & Browning (1951) for registering the movement and measuring the swimming rate of Tetrahymena. All the photomicrographic techniques mentioned above have the disadvantage of being limited to somewhat small areas of observation and thus giving no chance of carrying out more extensive studies on the locomotion of large-sized and relatively fast swimming Infusoria such as Paramecium, Stentor and many others. However, more recently Ferguson (1957) developed the horizontal and Dryl (1.958) the vertical arrangement for the photomacrographic recording of the movement of Infusoria. Both techniques render possible the simultaneous registration in a relatively wide area of observation of paths covered by hundreds or even thousands of animals. The studies now reported were made in an attempt to adapt the photomacrographic technique used in recording the movement of Infusoria for studies of the behaviour of Paramecium and (2) to verify the objections advanced by some authors against the avoiding reaction as being the sole factor causing the chemotactic response in Paramecium caudatum.
Motor response of Protozoa to chemical and many other stimuli was the subject of an exhaustive study by Jennings (1905). He found that Paramecia responded to chemotactic stimuli by means of a so-called "avoiding reaction" which, if fully expressed, was characterized by the following three stages: (1) backward swimming due to ciliary reversal, (2) turning to the aboral side and (3) swimming forward again at a new angle. Under certain conditions the animal may respond with a weak avoiding reaction, i.e. showing no backward swimming and merely swinging its anterior end in a small circle. The avoiding reaction appears on the boundary between two solutions of different chemotactic properties. In the case of positive chemotactic stimuli Paramecia swim into the tested solution without any response, showing the avoiding reaction upon leaving it. Consequently negative chemotaxis takes place when the animals show the avoiding reaction on the boundary between the surrounding medium and the solution under study. This mechanism of chemotactic reaction described by Jennings has been generally accepted by other authors, although with some exceptions. Alverdes (1922) expressed the view that Paramecia may respond to chemical stimuli by means of motor response other than that bf the avoiding reaction, e.g. by swimming along arc-lines, by adoral instead ofaboral turnings, etc. Similar objections to Jennings' avoiding reaction were stated by Parducz (1956a, 1956b). In studies of the behaviour of Infusoria the movement of animals has usually been recorded by means of hand drawings made from microscopic observations (Chase & Glaser, 1930; Dembowski, 1922). An entirely new device for recording the locomotion of Protozoa was developed by Gebauer (1930): In conditions of dark-ground illumination he used time-exposure photomicrography for recording the galvanotactic response in Polytoma uvella. A similar technique was introduced by Rothschild & Swann (1949) for recording the locomotion of
Materials and Methods
The experiments were made with a strain of Paramecium caudatum isolated in 1955 near Warsaw and subsequently grown in a mass culture on standard lettuce infusion inoculated with Aerobacter aerogenes (Sonneborn, 1950). One day before the experiment was begun a dense culture of Paramecium was diluted in the proportion of 1:2 with citrate-phosphate buffer solution prepared according to the formula given by the author (Dryl, 1959a): sodium citrate 0.1M.20 ml., sodium phosphate monobasic 0.1 M. 10 ml., sodium phosphate dibasic 0-1 M. 10 ml., redistilled water 945 ml. and CaC12 0.1 M. 15 ml. (Dryl, 1959a). In order to 393
394
ANIMAL
BEHAVIOUR,
avoid precipitation the CaC12 was the last reagent added during preparation of the solution of calcium salts. This solution proved to be not toxic for Paramecium aurelia and Paramecium caudatum. Buffer solutions of pH 5-63, 7.60 and 8-35 were prepared by varying the proportions of mono- and di-basic sodium phosphate. NaC1, KC1, CaC12 and MgC12 solutions were prepared by diluting the chemicals with the citrate-phosphate buffer solution of pH 7.60. (For long lasting series of experiments it is recommended that the buffer solutions should be kept in sterile conditions and to place them in an ice-box before using them in tests.) The determinations of pH were carried out with the aid of a Cambridge Instrument Company Potentiometer having an accuracy of up to 0.01 pH. The methods used for washing and collecting Paramecia have been fully described elsewhere (Dryl, 1961a). In the present series of experiments the movement of Paramecia was recorded using a modification (Dryl, 1961) of the photomacrographic technique described by Dryl (1958) with some improvements as indicated in a recent study (Dryl, 1961b). Beams of light from two projectors were directed through heat-filters from below and obliquely to the surface of a glassplate and also obliquely to the camera optic axis. In this way a dark-ground illumination was obtained. A reflex type camera suitably adapted for taking photomacrographs was fixed vertically above the glass plate in a stand which made possible the regulation of the distance between the camera lens and the subject under observation. A dark-room electric timer was used for regulating the length of the exposure time. All the experiments were performed in the dark-room. When all the preliminary arrangements were made, a glass plate 10 by 15 cm. with a rough margin 1 cm. wide was placed horizontally on the stage as shown on Fig. 1. Six or seven ml. of buffer solution ("the surrounding medium") was spread uniformly over the surface of the glass plate until it reached the margin. The layer of solution covering the glass plate was of approximate thickness 0.5-0.6 him. The effect of evaporation during the relatively short period of testing was found to be negligible. All the tests were performed at a temperature of 18 + 1°C. At each of the four corners of the glass plate 2-3 drops of medium containing dense colonies of Paramecia were placed using
XI,
2-3
a micropipette and then 8 to 10 drops of the test solution was pipetted into the middle area of the plate. Paramecia swim actively into the '"surrounding medium" and after 1 to 2 minutes the animals are seen to be uniformly dispersed in it. During tile course of experiment Paramecia look like small, bright dots moving quickly on the dark background. The chemotactie effect appears on the boundary between the surrounding and tested medium and the motor response of Infusoria is recorded by taking 5- or 10seconds time-exposure photographs. The direction of movement of Paramecia was marked by rapid opening of the lens-diaphragm of the camera during the last 0.5 second of exposure. This operation multiplies the amount of light admitted into the camera and makes the final selection of the recorded path covered by Infusoria appear on the negative to be of greater thickness than that of the preceding section. The photographic equipment necessary for recording the movement of Infusoria is shown on Fig. 1. Results and Discussion In buffer solutions Paramecia swam along spiral lines without turnings. The avoiding reaction appeared as soon as the animals approached the negative chemotactic medium and it was recorded on the negative as an irregular zigzag line. It is known that Paramecium shows a positive chemotactic response to a weakly acid medium with an optimum pH range 5.2-6-2, this having been previously demonstrated by the author (Dryl, 1959b). Positive reaction to the optimum pH is shown on Fig. 2. Paramecia were placed in a buffer solution of pH 8.35. The animals swam into the tested solution ofpH 5.63 without any reaction, yet they showed the avoiding reaction at each contact with the surrounding medium which they had just left. A typical response by a single amimal is shown on Fig. 3. Analysing the path covered by this Infusorian during 45 seconds, it is easy to see that the animal responded in a different manner to each successive contact with the negative chemotactic stimulus in the surrounding medium. Nevertheless, even in this case, all the negative motor response could be recognized as the avoiding reaction according to the definition given by Jennings. The negative chemotactic response of Paramecia placed in a buffer solution of pH 5.63 to a weakly alkaline medium (pH 8.35) is demonstrated in Fig. 4. In this case the animals showed
DRYL: CONTRIBUTIONS TO MECHANISM OF CHEMOTACTIC RESPONSE IN Paramecium eaudatum an avoiding reaction at each contact with the negative chemotactic stimulus in the tested medium. It was proved that Paramecia show more or less typical avoiding reactions towards strong negative chemotactic concentrations (40 raM.) of NaC1, CaC12 and M g C I 2. However, an entirely different motor response was observed when 40 mM. KC1 solution was applied as a chemotactic stimulus. It was found by observation as means of a low power dissection microscope that in this case, instead of turnings typical of avoiding reaction, a peculiar disturbance of movement appeared on the boundary of KC1 solution, namely rotation around the transverse axis of the body. This kind of motor response lasted 4 to 5 seconds and sometimes longer, and in consequence the forward movement of Paramecia nearly ceased at the boundary of the KC1 solution. This phenomenon was registered on the negative as large irregular spots (Fig. 5). In a recent study (Dryl, 1961a) a remarkable slackening of the forward movement of Param e c i u m caudatum was noticed in negative chemotactic threshold concentrations of NaC1, KC1, BaC12 and quinine solutions whereas in CaC12 and MgC12 solutions no significant change of swimming rate in relation to control was observed. The results achieved in another series of experiments indicated a close relationship between the optimum p H for chemotaxis and the p H range of highest swimming rate in Paramecium (Dryl, 1961b). All these findings and the main contribution from the present work provide additional evidence that when ehemotaxis of Paramecium is investigated by more accurate methods, both from qualitative and quantitative points of view, it appears to be a more complicated phenomenon than it was previously believed to be. Further work on these lines might yield valuable information about the mechanism of chemotactic response in Infusoria. All findings described in this section were confirmed by direct observations from the low power dissecting microscope and were partially recorded on a 16 mm. cinematographic film.
Summary The mechanism of the chemotactic reaction of P a r a c e m i u m caudatum was analysed using the time-exposure photomacrographic technique for recording the movement of Infusoria. Paramecia showed a more or less typical Jennings "avoiding reaction" towards p H
395
changes of the medium and to many other chemotactic stimuli, such as NaC1, CaC12, MgC12. Nevertheless, in a 40 mM. KC1 solution the animals; instead of taking avoiding action, showed a peculiar m o t o r response which lasted 4 to 5 seconds and sometimes longer and consisted mainly of rotations around the transverse axis of the body. It is emphasized that both the kind and the duration of m o t o r response to 40 raM. KC1 solution are in strong contradiction to the generally accepted view that avoiding reaction is the only m o t o r response of Paramecia to a chemotactic stimulus in the medium.
REFERENCES Alverdes, F. (1922). Zur Lehre yon den Reaktionen der Organismen auf atissere Reize. Biol. Zentrbl., 42, 218-222. Chase, A. M. & Glaser, O. (1930). Forward movement of paramecium as a function of hydrogen ion concentration. J. Gen. Physiol., 13, 627-636. Dembowski, J. (1922). Untersuchungen iiber die Bewegung yon Paramecium caudatum in Tropfen verschiedener geometrischen Gestalt. Tray. Inst. Nencki., 1, nr. 8, 1-32. Dryl, S. (1958). Photographic registration of movement of protoxoa. Bull. Ac. Polon. Sci. Ser. Sci. Biol., 6, 429-430. Dryl, S. (1959a). Antigenic transformation in Paramecium aurelia after homologous antiserum treatment during autogamy and conjugation. J. Protozool. 6, suppl., abstr., nr. 96. Dryl, S. (1959b). Effects of adaptation to environment on chemotaxis of Paramecium caudatum. Acta. Biol. Exp., 19, 83-93. Dryl, S. (1961a). Chemotaxis in Paramecium caudatum as adaptive response of organism to its environment. Acta Biol. Exp., 21, in press. Dryl, S. (1961b). The velocity of the forward movement of Paramecium caudatum in relation to pH of medium. Bull. Ac. Polon. Sci., Ser. Sci. Biol. 9 in press. Fergusson, M. L. (1957). Photographic technique for quantitative studies of paramecia and other motile cells. Physiol. Zool., 30, 208-215. Gebauer, H. (1930). Zur Kenntnis der Galvanotaxis yon Polytoma uvella und einigen anderen Volovocineen. Beitr. Biol. Pfl, 18, 463-500. Harris, H. (1953). Chemota×is of granulocytes. J. Path. Bact., 66, 135-146. Jennings, H. S. (1905). Das Verhalten der Niederen Organismen unter natiirlichen und experimentellen Bedingungen. Leipzig. Parducz, B. (1956a). Reizp.hysiologischeUntersuchungen an Ziliaten. IV. Uber das Empfindungs---bzw. Reaktions-vermOgen yon Paramecium. Acta Biol. Ae. Sci. Hung., 6, 289-316. Parducz, B. (1956b). Reizphysiologische Untersuchungen an Ziliaten. V. Zum physiologischen Mechanismus der sog. Fluchtreaktion und der Raumorientierung. Aeta Biol, Ac, Sci. Hung., 7, 73-99,
DRYL: CONTRIBUTIONS TO MECHANISM OF CHEMOTACTIC RESPONSE IN Paramecium eaudatum PLATE
IX
Fig. 1. The photographic equipment for recording the movement of Infusoria: c--camera, g--glass plate 10, by 15 cm. covered with solution containing Paramecia p--projector, h--heat-filter, e--electric timer.
Fig. 2. Positive chemotactic response of Paramecia to the buffer solution of pH 5.6. The pH of surrounding medium 8.35. Exposure time--10 seconds.
Atom. Behav.~ 11, 2-3
396
ANIMAL
BEHAVIOUR,
Rothschild, Lord &Swann, M. M. (1949). The fertilization reaction in the sea-urchin egg. A propagated response to sperm attachment. J. exp. Biol., 26, 164-176. Sonneborn, T. M. (t950). Methods in general biology, and genetics of Paramecium aurelia. J. exp. ZooL 113, 87-147.
XI,
2-3
Wingo, W. J. & Browning, J. (1951). Measurement of swimming speed of Tetrahymena geleii by stroboscopic photomicrography. J. exp. Zool., 117, 441-449. (Accepted for publication 5th November, 1962; Ms. number: 213).
ANIMAL
BEHAVIOUR, PLATE
XI,
2-3
X
Fig. 3. Positive chemotactic response of single Paramecium to the buffer solution of pH 5.6. The pH of surroinding medium 8.15. Exposure time--45 seconds.
Fig, 4. Negative chemotactic response of Paramecia to the buffer solution of pH 8' 35. The pH of surrounding medium 5-6. The typical avoiding reactions/turnings/recorded on the boundary of alkaline medium. Exposure time--10 seconds: Scale:the same as on Fig. 2.
Fig. 5. Motor response of Paramecia towards 40 ml. KC1 solution. The KC1 solution diluted with the same citratephosphate buffer solution (pH 7-6) which is present in the surrounding medium. On the left: A peculiar motor response on the boundary of KC1 solution recorded as the white irregular spots. On the right: Paramecia approaching the boundary of KC1 solution. Exposure time--15 seconds. Scale: the same as on Fig. 2.