JP5322294B2 - Action control device and action control method - Google Patents

Description

  The present invention relates to a behavior control device and a behavior control method for controlling the behavior of microorganisms, and particularly to a behavior control device and a behavior control method for controlling the behavior of small crustaceans represented by daphnia.

  Microorganisms may behave unidirectionally in response to stimuli existing in the environment. This property is called chemotaxis. Depending on the type of stimulation, there are pressure motility, chemical motility, electromotility, magnetic motility, gravity motility, water motility, photo motility, water motility, thermo motility, contact motility, etc. There are positive chemotaxis toward the stimulus and negative chemotaxis away from the stimulus. Each microbe does not have all the chemotaxis, and what the chemotaxis has depends on the microbe. When a stimulus causes an action, if the direction is random, it is called “mobility” and is distinguished from running.

  The inventors of the present invention have so far conducted research to control the behavior of microorganisms using the above-described chemotaxis and mechanically use the microorganisms as “living micromachines” (see Non-Patent Document 1). Specifically, we have developed systems that control behaviors of protozoa such as Paramecium, etc. using weak electric fields, and systems that control behaviors of protozoa, such as Euglena, using general light and laser light. .

A. Itoh, "Motion Control of Protozoa for Bio-MEMS", IEEE / ASME Transaction on Mechatronics, Vol.5, No.2, P181-188, June, 2000.

  However, protists such as Paramecium and Euglena have extremely large variations in response among individuals. That is, in order to apply these protists as “living micromachines”, the current situation is that they are struggling due to the poor performance of behavior control.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a behavior control device and a behavior control method that can control the behavior of microorganisms with high accuracy.

  A first feature of the present invention is a behavior control device for controlling the behavior of a crustacean in water using the crustacean's chemotaxis, the cylindrical container for containing the crustacean, and the cylindrical shape A plurality of control light sources for irradiating blue light installed on the circumferential wall surface of the container, and a light source control for turning on the control light source installed in a direction in which the crustaceans are to be swam among the plurality of control light sources Means.

  The second feature of the present invention is that, in the behavior control device, the light source control means increases the light intensity of the blue light by providing continuity in a direction in which the crustaceans want to swim.

  The third feature of the present invention is that the behavior control apparatus further includes a confirmation light source that emits red light as illumination for confirming the behavior of the crustacean.

  A fourth feature of the present invention is that, in the behavior control device, the wall surface of the cylindrical container is painted in matte black.

  The fifth feature of the present invention is that, in the behavior control device, the light source control means switches a position of the control light source to be turned on at a timing according to a response delay characteristic of the crustacean.

According to a sixth aspect of the present invention, in the behavior control apparatus, when the crustacea is swimming toward the point B at the point D that is not on the path connecting the point A and the point B, When the direction of the point B when viewed from the point A is θ ₁ and the direction of the point B when viewed from the point D is θ ₂ , an angle θ (θ = θ ₁ + Kp (θ ₁ −θ ₂ )) is shown. The control light source installed at the position is turned on.

  According to a seventh aspect of the present invention, in the behavior control apparatus, a photographing unit that photographs the action scene of the crustacea, and a game that reflects the behavior scene of the crustacean photographed by the photographing unit in a computer game Means.

  An eighth feature of the present invention is that, in the behavior control device, the crustacean is a daphnia.

  A ninth feature of the present invention is a method for controlling the behavior of crustaceans in water by utilizing the crustacean's chemotaxis, wherein blue light is applied to a circumferential wall surface of a cylindrical container for containing the crustaceans. A plurality of control light sources for irradiating the light source, and turning on the control light source installed in a direction in which the crustacean is desired to swim among the plurality of control light sources.

  ADVANTAGE OF THE INVENTION According to this invention, the action control apparatus and action control method which can control the action of microorganisms with high precision can be provided.

It is a figure which shows the structure of the action control apparatus in embodiment of this invention. It is a figure which shows a mode that a suspended thread was affixed on the back of a daphnia. It is a figure which shows the relationship between the operation frequency of a 2nd tactile sense, and the irradiation position of a laser beam. It is a figure which shows the relationship between the swing width of a 2nd tactile sense, and the irradiation position of a laser beam. It is a figure which shows the general view of a behavior control pool. It is a figure which shows an example of an action control experimental scenery. It is a figure which shows the swimming path | route at the time of switching the position of the light source to light. It is a figure which shows the time taken for reaction when the position of the light source to light is switched. It is a figure for demonstrating the outline | summary of a control equation. It is a figure which shows a mode that the plastic ball is conveyed to the daphnia.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The behavior control device according to the embodiment of the present invention is a device that controls the behavior of daphnia using the mobility, and as shown in FIG. 1, a video camera 10, a personal computer 20, a microcomputer 30, The behavior control pool 40 and the joystick 50 are provided. The video camera 10 is a device that photographs daphnids in the behavior control pool 40. The personal computer 20 is a device that performs various calculations using signals from the video camera 10 and the joystick 50. The microcomputer 30 is a device that controls equipment installed in the behavior control pool 40 based on a signal from the personal computer 20. The behavior control pool 40 includes a cylindrical container for containing a daphnia, a plurality of control light sources that emit blue light, and the like.

  By the way, the present inventors have examined behavior control using the motility of various protists and its engineering utilization method. However, underwater microorganisms include not only these unicellular organisms but also various multicellular organisms such as small crustaceans represented by Daphnia, and these are known to have chemotaxis. At present, no study has been made on controlling these multicellular organisms using chemotaxis. Therefore, in the present invention, a behavior control method using phototacticity was examined for small crustaceans, mainly Daphnia.

  First of all, when using phototaxis, it is necessary to know the mechanism by which Daphnia gathers in blue light. Therefore, with the daphnia fixed, blue laser light was irradiated from various directions, and the reaction of the daphnia at that time was investigated. Daphnia basically swims by moving a large second antenna. The movement of the second antenna was recorded with a high-speed video camera, and the response frequency of the second antenna was first examined when the wavelength, intensity, irradiation position, etc. of the laser beam were changed. As shown in FIG. 2, the daphnia was fixed by a method in which the hair or ultra fine suspension thread was attached to the back of the daphnia with an instantaneous adhesive, with reference to the method used in the past research on daphnia. As a result of the experiment, the operating frequency of the antenna was maximized with the blue laser (wavelength 473 nm), and the frequency increased as the intensity increased. As for the irradiation position, as shown in FIG. 3, the frequency increased as irradiation was performed on a position closer to the eyes. Next, as a result of irradiating the blue laser toward the eyes from various angles, as shown in FIG. 4, when irradiating from the top and diagonally right, the width of the left tactile sensation increases and when illuminating from diagonally left Found that the right tactile amplitude tends to increase. That is, it is considered that the daphnia is swimming toward the light by greatly shaking the sense of touch in the direction opposite to the light. Note that there was no significant difference between the left and right in the movement frequency and swing time.

  Based on the above, we investigated a method of behavior control with blue light in the pool. In the case of daphnia, since it shows a clear directional light mobility, it seems to be good to distribute the light intensity of blue light so that it gradually increases toward the light source. Attempts were made to control the behavior with a laser using a device for Euglena but the behavior could not be controlled well with a laser with a small irradiation area. Therefore, we decided to use ultra-bright blue LEDs with a wavelength of 470 nm and a wide angle of 60 degrees, which were collected most frequently from basic experiments, for behavior control, and made various types of prototypes and examinations of LED arrangements and pool structures. did. As a result, it was found that when the light reflected in the pool tried to go to the reflected light, it was difficult to control, and the pool was painted with matte black except for the LED. Finally, as shown in FIG. 5, 24 LEDs (light sources) 42 are mounted around a cylindrical container 41 having a diameter of 130 mm and a depth of 15 mm, and light in a direction in which the joystick 50 is inclined is irradiated. A type behavior control pool 40 was prototyped.

  Daphnia's phototaxis resembles that of Euglena in the wavelength range of reaction, reacts best to blue light, and has little reaction to red light. This means that blue light can be used as the behavior control light, and red light can be used as the behavior confirmation illumination of Euglena. That is, if a confirmation light source that emits red light is provided, the behavior of the daphnia can be accurately confirmed without affecting the behavior control of the daphnia.

  As a result of conducting a behavioral control experiment of Daphnia 43 by manual control, it became clear that controllability is much better than when electric field control is performed on Paramecium, and it can be freely controlled. For example, FIG. 6 shows an experimental scene when the daphnia 43 is swung along the star path. It has been found that even when such a star-shaped path is allowed to swim for five laps, the behavior of the daphnia 43 can be controlled with sufficient accuracy to recognize the star shape.

  Next, we investigated the response delay characteristics when the supported swimming direction was switched. As a result of the investigation, it was found that the swimming always went in a substantially straight line toward the direction of the light source, and as shown in FIG. 7, it was found that there was a reaction delay when the swimming direction was switched. Also, it can be seen that the time required for the reaction when the position of the light source 42 to be turned on is about 0.3 to 0.6 seconds, as shown in FIG. 8, when the light of the LED 42 is switched, The smaller the angle with respect to the traveling direction so far, the better the response. Therefore, the position of the light source 42 to be turned on may be switched at a timing according to such a response delay characteristic. For example, when it is desired to switch the swimming direction in a direction in which the reaction delay time is 0.3 seconds, it is preferable to switch the position of the light source 42 to be lit 0.3 seconds before the daphnia 43 reaches the switching point.

Next, an experiment for automatically controlling the behavior of the daphnia 43 was performed. Here, as shown in FIG. 9, it is assumed that the daphnia 43 is swimming toward the point B at a position (point D) that is not on the path connecting the point A and the point B. In this case, if the direction of the point B when viewed from the point A is θ ₁ and the direction of the point B when viewed from the point D is θ ₂ , ＤABD can be expressed as θ ₁ −θ ₂ . Therefore, when the light source 42 installed at the position of the angle θ shown in the following equation is turned on, the daphnia 43 can be guided on the path connecting the point A and the point B, and it is possible to swim on this path. . When the value of the proportional coefficient Kp was tested between 0 and 2, a good result was obtained when the value was 1.5. The position of the daphnia 43 can be detected by analyzing an image taken by the video camera 10 with the personal computer 20.

θ = θ ₁ + Kp (θ ₁ −θ ₂ )
In addition, an experiment was carried out in which an object was transported by colliding it with a Daphnia magna by manual operation. A polypropylene plate was processed into this character as a transport object, and it was verified whether it could be transported using several sizes. As a result of the experiment, a transport object having a long side of up to 30 mm was successfully collided and transported. From this result, it was found that the power of Daphnia is greater than that of protists, and has the ability to transport objects larger than its own body length. For example, as shown in FIG. 10, a plastic ball having a maximum diameter of 8 mm was successfully transported to a daphnia.

  As described above, in the present invention, as a result of investigating the chemotaxis of Daphnia magna, it has been clarified that blue light has a strong positive directional phototaxis. We have also developed a behavior control method in which blue LEDs are placed side by side on the circumferential wall surface of a petri dish-like pool and the LEDs in the direction in which the joystick tilts are lit. As a result of experiments using these devices, it became clear that behavior control with much better control than protists is possible. Daphnia is larger than protists, so its use as a micromachine is limited, but there are also small types, and including the use of larvae, there is a possibility of being able to perform micro work that is not possible with protists due to high controllability. It is also possible to use the sense of touch as a tool with the daphnia fixed.

  Furthermore, the freedom of behavior control shown by Daphnia is promising for hobby and leisure applications that people enjoy by manipulating Daphnia. In other words, when breeding Paramecium, there is a problem with the odor of the dough emitted by the breeding solution. On the other hand, for Daphnia, (1) phytoplankton is used as food, and it is only necessary to give water from the green pond, so it does not smell like Paramecium, and (2) its appearance is similar to shrimp crab. Therefore, it feels cute, (3) 2-4mm for large ones, it is large and easy to see as a microorganism, (4) Above all, the daphnia that I thought was just floating Promising for hobby use seems to be extremely high.

  There is also a method in which a real Daphnia appears as the main role of a computer game by superimposing the image of a Daphnia photographed by the video camera 10. In this case, the price of the device could be made sufficiently lower than that of Paramecium, considering the size of the daphnia. In addition, there is a possibility that Daphnia can be used as a pet and can be competed like an agility competition for dogs competing with pets. Such a game can be realized, for example, by superimposing an image of an obstacle on the image of the action scenery of a daphnia photographed by the video camera 10. In this case, a score is added every time an obstacle is passed, and when a certain score is reached, food may be fed to the real daphnia or oxygen may be supplied to the breeding solution. In addition, a game can be conceived in which the daphnia competes for the time by passing a maze or transporting an object. Such a game may be installed in the personal computer 20 or in another computer connected to the personal computer 20 via a network.

  In the above description, 24 LEDs 42 are mounted around the cylindrical container 41. However, the number of LEDs 42 is not limited to this. For example, 48 LEDs 42, which are double, are mounted. May be. Moreover, what is necessary is just to mount | wear the ring | wheel of LED42 around the cylindrical container 41 many times, when you want to control the action of a daphnia in space instead of controlling it in a plane. In this way, since the LEDs 42 are arranged not only in the horizontal direction but also in the vertical direction, it is possible to control the behavior of daphnia in space.

  In the above description, the LED is used as the light source, but the present invention is not limited to this. That is, other light sources may be employed as long as the light intensity of blue light can be increased by providing continuity in the direction in which the daphnia is desired to swim.

DESCRIPTION OF SYMBOLS 10 ... Video camera 20 ... Personal computer 30 ... Microcomputer 40 ... Action control pool 41 ... Cylindrical container 42 ... LED (light source)
43 ... Daphnia 50 ... Joystick

Claims (9)

A device for controlling crustacean behavior in water using the crustacean chemotaxis,
A cylindrical container for containing the crustaceans;
A plurality of control light sources for irradiating blue light, installed on the circumferential wall surface of the cylindrical container;
A light source control means for turning on the control light source installed in a direction in which the crustaceans want to swim among the plurality of control light sources;
A behavior control device comprising:   2. The behavior control apparatus according to claim 1, wherein the light source control means increases the light intensity of the blue light by providing continuity in a direction in which the crustaceans want to swim.   The behavior control apparatus according to claim 1, further comprising a confirmation light source that emits red light as illumination for confirming the behavior of the crustacean.   The behavior control apparatus according to claim 1, wherein a wall surface of the cylindrical container is painted with matte black.   5. The behavior control device according to claim 1, wherein the light source control unit switches a position of the control light source to be turned on at a timing according to a response delay characteristic of the crustacean. When the crustacea is swimming toward the point B at the point D that is not on the path connecting the point A and the point B, the light source control means sets the direction of the point B when viewed from the point A to θ ₁ , When the direction of the point B when viewed from the point D is θ ₂ , the control light source installed at the position indicated by the angle θ (θ = θ ₁ + Kp (θ ₁ −θ ₂ )) is turned on. The behavior control device according to claim 1, wherein the behavior control device is characterized in that:   7. The apparatus according to claim 1, further comprising photographing means for photographing the action scenery of the crustacean and game means for reflecting the action scenery of the crustacean photographed by the photographing means in a computer game. The behavior control device according to any one of the above.   The behavior control apparatus according to claim 1, wherein the crustacean is a daphnia. A method of controlling crustacean behavior in water using the crustacean chemotaxis,
A plurality of control light sources for irradiating blue light on a circumferential wall surface of a cylindrical container for containing the crustaceans are installed, and the control is installed in a direction in which the crustaceans are desired to swim among the plurality of control light sources. A behavior control method characterized by turning on a light source.