JP2007163186A - Electrophoretic system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact inexpensive electrophoretic system which facilitates the movability of an apparatus, does not receive a restriction in an installation place, can flexibly correspond to the dimension of a support and can acquire the image reduced in noise during electrophoretic image photographing and caused by fluorescent color development or coloration development. <P>SOLUTION: After an electrophoretic image is acquired as a color image, images divided at every color component are acquired. Next, the images divided into color components are reconstituted in the ratio corresponding to the color development wavelength characteristics of a fluorescent reagent or a coloration reagent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophoresis system for analyzing biopolymers, particularly nucleic acids.

  The present invention relates to a nucleic acid electrophoresis system, and more specifically, the nucleic acid is separated into molecular weights by the electrophoresis system, the image is taken, and the nucleic acid is cut out and extracted and recovered from the electrophoresis support. It relates to technology to be performed

  The present invention relates to an electrophoresis system, and in particular, in order to obtain an image as a result of separating nucleic acids by molecular weight by electrophoresis, an image corresponding to a coloring wavelength or a coloring wavelength can be easily obtained. is there.

  2. Description of the Related Art Conventionally, separation and analysis methods based on the molecular weight of an electrophoretic apparatus for biopolymers, particularly nucleic acids, are simple and inexpensive and have high analysis accuracy, and thus have been widely used as nucleic acid analysis apparatuses. Hereinafter, electrophoresis of nucleic acids will be described.

  Analysis of nucleic acid by electrophoresis is configured by first attaching a support on which a nucleic acid sample moves to an electrophoresis tank in which electrodes that conduct voltage are brought into contact with both ends with a buffer solution. As a support for this electrophoresis, a gel substance such as agarose or polyacrylamide is used. As a form of the apparatus, a horizontal electrophoresis apparatus in which a support is installed on a lateral surface is widely used because of easy handling. In the electrophoresis operation, a nucleic acid sample is dropped into a groove formed at one end of the support, a voltage is applied to both ends of the support, and the nucleic acid sample in the support is electrically moved. At this time, the movement of the nucleic acid sample is restricted by the network structure of the support, and the mobility becomes slower as the molecular weight increases, so that separation based on the molecular weight of the nucleic acid becomes possible. Further, the nucleic acid thus separated is cut out from the support for each nucleic acid fraction, and an appropriate method such as the method of Vogelstein and Gillespie (Non-patent Document 1) or the method described in Molecular Cloning (Non-patent Document 2). Thus, the nucleic acid can be extracted and recovered, and used for separation and removal of impurities from a nucleic acid sample, incorporation into a vector, sequence mapping, and the like.

  As a method for collecting the nucleic acid fraction, there is a method using column chromatography represented by high performance liquid chromatography in addition to a method using an electrophoresis apparatus. Considering the simplicity, flexibility, apparatus price, maintenance cost, etc., the method using the electrophoresis apparatus is extremely efficient, and thus the method using electrophoresis is exclusively used for collecting the nucleic acid fraction. .

  In order to further improve the convenience of this electrophoresis apparatus, proposals have been made to reduce the size of the support and to suppress Joule heat generated by voltage application. The place is also not restricted and contributes to the improvement of work efficiency (Patent Document 1 and Patent Document 2).

  Next, regarding a method for detecting nucleic acids separated by electrophoresis, a nucleic acid-binding fluorescent reagent such as ethidium bromide is mixed in the support in advance before electrophoresis, or the support is removed from these supports after electrophoresis. After dipping in the solution, the solution is infiltrated into the support, and the nucleic acid sample in the support is bound to the fluorescent reagent. The separated nucleic acid sample is visualized. Here, this apparatus for irradiating ultraviolet rays is called a transilluminator.

  The results of electrophoresis of nucleic acid samples visualized by this ultraviolet irradiation have been acquired by image capturing using a film camera. However, with the recent advancement of electronic devices, a charge coupled device (CCD) camera has been developed. Adopted electrophoretic imaging device has been proposed (Patent Literature 3, Non-Patent Literature 3), and it is possible to digitize the image. Compared with the film type, it is easier to shoot, save data, and computer. It has high affinity with digital devices and contributes to improving the working efficiency of a series of electrophoresis techniques as well as shortening electrophoresis.

  This CCD camera has the disadvantage that as the ambient temperature increases, dark current increases in the CCD itself, resulting in noise in the captured image. There have been proposed a method of installing a cooling element (Patent Document 4, Patent Document 5, and Patent Document 6), a method of cooling and radiating the entire electrophoretic imaging apparatus (Patent Document 7), and the like. On the other hand, when the CCD is not cooled, as a noise prevention method, an image reading area and a non-reading area are provided in the CCD, and the data of the non-reading area is subtracted from the data of the image reading area (for example, Patent Document 8). In order to prevent the incidence of ultraviolet light, which is excitation light, and blue-violet light, which is guide light for ultraviolet light, to the camera lens in a method for correcting dark current, and also for film-type cameras. In addition, there was a method of installing a filter that cuts off the transmission of these wavelengths in front of the camera lens. However, with a CCD camera, the above-mentioned ultraviolet and blue-violet light can be completely applied to the camera lens only by installing the filter. It is difficult to prevent incidence, and the incidence on these camera lenses causes noise in the acquired image. A method of subtracting image data at the time of excitation light irradiation to remove scattering noise caused by excitation light (Patent Document 9), or a method of installing a dichroic mirror to remove noise caused by excitation light (Patent Document 10) ) Etc. have been proposed, and even in the CCD type, it is possible to obtain an image having no noise equivalent to the film type.

  In recent years, it has been proposed to integrate these electrophoresis devices and image capturing devices to perform real-time monitoring of electrophoresis, enabling optimal nucleic acid separation analysis by electrophoresis and image acquisition. (Patent Document 11, Patent Document 12, and Patent Document 13).

For extraction and recovery of nucleic acid separated by electrophoresis from a support, conventionally, a target nucleic acid fraction is cut out from the support using a sharp blade, and suitable for non-patent document 1 or non-patent document 2, for example. In recent years, nucleic acids have been extracted and recovered by the method, but in recent years, apparatuses for mechanically cutting out nucleic acid fractions from a support and apparatuses for performing extraction and recovery mechanically (Patent Document 14, Patent Document 15, Patent Document 16, Patent Document) 17) is proposed, and the working efficiency is greatly improved as compared with the conventional manual method.
JP-A-10-288597 JP 2002-328113 A Japanese Patent No. 2838117 Japanese Patent Laid-Open No. 10-209419 Japanese Patent Laid-Open No. 10-215395 JP 2000-101888 A Japanese Patent Laid-Open No. 11-266382 Japanese Patent No. 2686166 JP 2000-292353 A JP 2003-35672 A JP 2000-105219 A JP 2002-357590 A JP 2003-240756 A Japanese Patent No. 3381484 Japanese Patent Laid-Open No. 2001-22176 Utility Model No. 310144 JP 2000-88804 A Vogelstein. B., Gillespie. D., Bulletin of the American Academy of Sciences (Proc. Natl. Acad. Sci. USA), 1979, 76, 615-619. Edited by Cold Spring Harbor Laboratory (Cold Spring), 1989, Sambrook. J., Fritsch. EF, Maniatis. T., “Molecular Cloning 2nd Edition” Harbor Laboratory Press), 6.22-6.35 Sutherland. JF et al., “Anal. Biochem.”, 1987, 163, 446-457.

  However, in the conventional electrophoresis apparatus, by reducing the size of the apparatus main body, the amount of nucleic acid sample can be reduced and the electrophoresis time can be shortened. Limited to determining the molecular weight of a nucleic acid sample in a sample, determining the presence or absence of contaminants in a nucleic acid sample, performing electrophoresis on a large or large number of samples, and It was difficult to collect an appropriate amount of the nucleic acid fraction separated by electrophoresis.

  Next, the convenience of the electrophoretic imaging device has been improved by adopting a CCD camera, but as with conventional film cameras, the results of electrophoresis from a small number of samples to a large number of samples, and the electrophoresis length In order to be able to cope with a support having various sizes of up to about 50 to 300 mm, it is necessary to design a wide shooting range, and as a result, the occupied area of the device and the outer size of the device itself are large. Therefore, it has been left as a problem from the photographing apparatus using the film type camera that the installation place is restricted.

  Since this CCD type camera has a defect that it is easy to capture noise in an image as compared with a film type, a method of irradiating excitation light and non-excitation light and subtracting a noise component from two types of images, Alternatively, a method of removing noise caused by excitation light by installing a dichroic mirror has been proposed, but the method of subtracting the excitation light image and the non-excitation light image has to be taken twice. The method of installing a dichroic mirror is complicated and causes the convenience and simplicity of electrophoretic image shooting to be reduced, for example, the configuration of the imaging element is complicated.

  Also, when the entire support having a relatively large size is to be photographed, the distance between the support that is the subject and the camera position must be increased, but as the distance increases, the nucleic acid in the support is increased. Since the fluorescence intensity of the sample is attenuated, an excessive amount of ultraviolet light must be used to excite the fluorescence so that it can be imaged even when the camera distance is long. A plurality of them are installed in parallel.

  However, from the viewpoint of the socket shape of the fluorescent tube and the workability of exchanging the fluorescent tube, there is a slight gap between the fluorescent tubes, so the amount of ultraviolet light is reduced at the fluorescent tube placement position and the gap position between the fluorescent tubes. Unevenness occurs. In addition, the fluorescence intensity of the nucleic acid sample held by the support that exists in a position parallel to the fluorescent tube is constant, whereas the nucleic acid sample that is held by the support that exists in a position perpendicular to the fluorescent tube. The problem was that the fluorescence intensity was not constant.

  Furthermore, due to the change over time and temperature characteristics of the fluorescent tube, there is a problem that it is difficult to always irradiate a certain amount of ultraviolet light even when a prescribed voltage is applied.

  In order to solve the problem caused by this camera distance, it is possible to widen the imaging range even if the camera distance is not long by setting the camera lens to a wide angle specification. Since it has the disadvantage of curving the image, it has the problem of making its use difficult.

Thus, in order to solve the problem caused by the distance between the support that is the subject and the camera position, it is necessary to irradiate the support with a higher amount of ultraviolet light than necessary. Subsequent test results using nucleic acid samples recovered from the support cannot be avoided because of the partial disruption of nucleic acid molecules induced by exposure and the formation of thymine bases in the nucleic acid molecule (thymine dimer). Had the problem of having to consider the existence of these effects.
In addition, ethidium bromide has conventionally been used as a nucleic acid-binding fluorescent reagent for visualizing the results of electrophoresis of nucleic acids, but in recent years it has higher sensitivity, higher selectivity, and lower toxicity than ethidium bromide. As shown in FIG. 8, the fluorescence reagents of ethidium bromide (A in FIG. 8), SYBR Green I (B in FIG. 8), and POPO-1 (C in FIG. 8) have been developed. As shown in the spectrum, the fluorescence wavelengths of various nucleic acid-binding fluorescent reagents differ from one fluorescent reagent to another (quoted from Molecular Probes, edited by Haughland, RP, Handbook of Fluorescent Probes and Research Products, 8th edition) ) Depending on the reagent used, do not replace the filter that limits the transmission wavelength installed in front of the camera lens in a timely manner. Re has been a problem that must.

  Next, in an apparatus in which electrophoresis and image capturing are integrated, real-time monitoring of electrophoresis is realized, and an optimal nucleic acid separation state can be detected. As the outer dimension of the electrophoresis apparatus increases, the outer dimension of the integrated apparatus itself also increases, so that the installation location is restricted and the ultraviolet light is intermittently exposed. However, partial breakage of nucleic acid molecules and formation of thymine dimer cannot be avoided, and there is a problem that it is inappropriate for nucleic acid recovery from a support.

  Therefore, electrophoresis in such an integrated apparatus has a problem that its use is limited only to separation analysis according to the molecular weight of the nucleic acid.

  In addition, since the method for determining the optimal nucleic acid separation state by real-time monitoring and stopping electrophoresis is manual as before, it is difficult to avoid waiting time until electrophoresis stops. In addition, although it has been devised to stop electrophoresis by setting a timer, in order to set the time to stop under the optimum conditions, it requires high experience in electrophoresis, such as fully understanding the condition settings. If you are unfamiliar with, you have the problem of not being an effective means.

  In addition, after electrophoresis stops, the nucleic acid sample does not stay in the support and diffuses naturally over time, so it is necessary to take an image immediately after stopping electrophoresis. There was a problem that it could not be an effective solution.

  Finally, since the nucleic acid fraction from the support after electrophoresis is cut out exclusively using a sharp knife, it is necessary to operate while directly viewing the ultraviolet rays. At this time, wear protective equipment to protect the worker from exposure to ultraviolet rays. Usually, ultraviolet lamps are mixed with blue-violet visible light as guide light in addition to ultraviolet light, so a high-intensity blue-violet visible light is used. It is necessary to look directly at the light, which causes serious eye strain to workers.

  Further, even during the extraction of the nucleic acid fraction, there is a problem that the nucleic acid sample generated after the stop of electrophoresis described above is spontaneously diffused in the support, and the extraction operation must be performed within a limited time. Was.

  The present invention has been made to solve the above-described conventional problems. The apparatus is easy to move, is not limited by the installation location, can flexibly support the dimensions of the support, and is electrophoresed. It is an object of the present invention to provide a small and inexpensive electrophoresis system that can acquire an image resulting from fluorescence development or color development with little noise during image capturing.

  In order to solve the above-described conventional problems, an electrophoresis system according to the present invention is an electrophoresis system for separating and analyzing a biopolymer sample. The electrophoresis system is configured to perform electrophoresis of the biopolymer sample using a support. A voltage is applied to both ends of the electrophoresis tank, the support provided in the electrophoresis tank, and the biopolymer sample is electrophoresed, and the result of electrophoresis of the biopolymer sample is photographed Image capturing means; and, from the image acquired by the image capturing means, calculating position information of the biopolymer fraction in the support, and cutting out means for cutting out the biopolymer fraction separated by the support An electrophoretic system capable of performing a series of steps from the start of electrophoresis of the biopolymer fraction to the extraction and collection of the electrophoretic biopolymer sample fraction. After the image capturing means for capturing the image of the electrophoresis result is obtained by dividing the image for each color component, the electrophoretic image is obtained by changing the color component ratio according to the coloring wavelength or the coloration wavelength of the image. Is reconfigured.

  In addition, the electrophoresis system according to the present invention is for synthesizing a plurality of electrophoresis result images divided and photographed by the image photographing means, or position information on the support for each of the electrophoresis result images. The position marker for acquisition is something other than the color development wavelength or coloration wavelength region of the electrophoresis result image, and after the electrophoresis result image is divided for each color component, the color development wavelength of the image Alternatively, when the electrophoretic image is reconstructed by changing the color component ratio according to the coloration wavelength, the position marker is not displayed.

  Furthermore, the electrophoresis system of the present invention provides a filter that restricts the light wavelength taken into the image pickup means for capturing an image of the electrophoresis result in accordance with the color development wavelength or coloration wavelength of the image. This is a visible light wavelength region transmission filter without using the spectral characteristics of a fluorescent reagent having a color wavelength or a color reagent.

In the electrophoresis system of the present invention, the image of the electrophoresis result is obtained by dividing the image into at least three kinds of color components, and then the image of each color component is obtained according to the color development wavelength or the coloration wavelength of the image. The image is reconstructed into images of different color components and an electrophoretic image is obtained.
In addition, the electrophoresis system according to the present invention is characterized in that the electrophoresis result image is initially acquired in color so that the electrophoresis result image can be divided into at least three color components. Is.

  In the electrophoresis system of the present invention, the image pickup means for taking an image of the electrophoresis result is a color type charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS) device, or a photodiode. The solid-state imaging device is characterized by digitizing and acquiring an electrophoretic result image.

  According to the electrophoresis system of the present invention, the electrophoresis is performed, the nucleic acid sample is separated by electrophoresis, the image of the electrophoresis result is photographed, and then the nucleic acid fraction separated from the photographed image data is collected. In the electrophoresis system that can perform a series of operations for cutting out the nucleic acid fraction from the support based on the position information of the above, when photographing an image of the result of the electrophoresis, there are few noise components, fluorescence development, Alternatively, it is possible to obtain a small and inexpensive electrophoresis system that can easily acquire an image resulting from color development and has mobility that does not limit the installation location of the system body.

Hereinafter, embodiments of the electrophoresis system of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is a perspective view of a schematic configuration inside the electrophoresis system according to the first embodiment of the present invention, and FIG. 2 is a block diagram of the electrophoresis system according to the first embodiment.

  The electrophoresis system according to the first embodiment mainly includes a table mechanism 40 that can be driven in the Y-axis direction, a carriage mechanism 60 that can be driven in the X-axis direction, a clipping unit 62 that can be driven in the Z-axis direction, and an image photographing unit 61. , And an ultraviolet irradiation unit 70. In the table mechanism 40, a driving motor (not shown) capable of controlling the driving amount, such as a stepping motor, is connected to the table mechanism power transmission unit 42 via a gear, so that the rotational power of the driving motor is linearly moved. The table mechanism 40 is driven by the conversion. The center portion of the table mechanism 40 is opened in a window shape, or an ultraviolet light transmissive acrylic resin (for example, Sumipex 010 manufactured by Sumitomo Chemical) or an ultraviolet light transmissive glass (for example, UV-33S manufactured by Asahi Techno Glass) For example, UV-29). Further, the table mechanism 40 is capable of inserting a slide table 45 that is slidable in the Y-axis direction, and the slide table 45 has a central opening in the shape of a window like the table mechanism 40, or It is made of a material having high ultraviolet transparency as described above, and can move in the Y-axis direction within the table mechanism 40. Further, the slide table 45 has an installation part for the electrophoresis tank 10 and an installation part for the cutting instrument holder 30. The electrophoresis tank 10 that can be placed on the slide table 45 has a support-attached surface 11 for attaching an electrophoresis gel serving as a support for electrophoresis, and the electricity installed on the support-attached surface 11. Electrophoresis system main body having electrodes 14 such as platinum wires for applying a voltage to both ends of electrophoresis gel 101 and having a power receiving unit (not shown) for applying a voltage to the electrodes And a power supply unit (not shown) provided in the detachable structure.

  Immediately above the table mechanism 40 is provided a carriage mechanism 60 integrally including an image photographing means 61 and a cutting means 62 capable of gripping the cutting tool 21, and the carriage mechanism 60 includes a screw nut. 66, a lead screw 64, a linear motion shaft 63, a gear 58, and the like can be driven in the X-axis direction. In the first embodiment, the image photographing means 61 mounted on the carriage mechanism 60 employs an area CCD camera and can digitize the photographed electrophoretic pattern image. Further, the cutting means 62 mounted on the carriage mechanism 60 has the cutting tool 20 for cutting the support from the electrophoresis tank so that it can be driven in the Z-axis direction by a cutting tool operating motor 56. Thus, the Z-axis direction is a direction perpendicular to the support-equipped surface 11 in the electrophoresis tank 10.

  Further, the cutting means 62 is provided with a cutting tool gripping pin 65 for gripping the cutting tool 20 on the lower surface thereof, and the cutting tool gripping pin 65 can be connected to the upper connecting portion 21 of the cutting tool 20. It has become a structure.

  Further, an ultraviolet irradiation unit 70 is provided below the table mechanism 40. The ultraviolet irradiation unit 70 includes an ultraviolet light source 71 and a first optical filter 91 that prevents transmission of wavelengths in the visible light region derived from the ultraviolet light source 71 between the ultraviolet light source 71 and the table mechanism 40. To do. The image photographing means 61 mounted on the carriage mechanism 60 is provided with a second optical filter 92 for preventing the transmission of ultraviolet rays.

  Further, FIG. 2 shows a block configuration of the electrophoresis system of the first embodiment. In the first embodiment, as shown in FIG. 2, the ultraviolet irradiation unit 70 is further turned on / off, and an image is displayed. Control of photographing by the photographing means 61, control of the voltage of the electrophoresis tank 10 based on the photographed image, driving of the table mechanism 40 for automatically or manually cutting out the gel at a designated location, carriage mechanism 60 And a system control unit 120 for controlling the drive of the cutting-out means 62.

  Further, in the system control unit 120, the table mechanism 40 and the carriage mechanism 60, the CPU 124 and the interface unit 125 for operating the image photographing unit 61, and a recording apparatus that holds a plurality of gel images obtained by divided photographing. 126, an image compositing means 121 for compositing the divided images into one image, dividing the composite image for each color component, and converting the color component ratio, It includes color component ratio conversion / reconstruction means 122 that performs reconstruction, and nucleic acid fraction position measurement means 123 that measures the position of the nucleic acid fraction from the photographed gel image.

The operation and action of the electrophoresis system of the first embodiment configured as described above will be described below.
First, the electrophoresis gel 101 is placed on the support surface 11 in the electrophoresis tank 10. After injecting a nucleic acid sample into an injection port provided at one end of an electrophoresis gel 101 as a support, a prescribed voltage is applied between a pair of electrodes 14 provided at both ends of the gel. When a voltage is applied, the negatively charged nucleic acid sample starts moving from the cathode toward the anode. Since the inside of the gel is a fine network, the speed of movement of the nucleic acid sample moving inside the gel varies depending on the size of its molecular weight. They are separated into strips of approximately the same width as the inlet. At this time, when the ultraviolet light source 71 is turned on and the nucleic acid sample is irradiated with ultraviolet light, a nucleic acid-binding fluorescent reagent such as ethidium bromide mixed in advance with the nucleic acid sample or pre-mixed with the electrophoresis gel emits fluorescence. . By photographing this fluorescence with the image photographing means 61, it is possible to obtain an image of an electrophoretic pattern in which the nucleic acid sample is separated in a band shape based on the molecular weight. At this time, the first optical filter 91 (for example, Sumitomo Chemical's Sumipex 010, Asahi Techno Glass UV-33S, UV-29, etc.) causes the nucleic acid-binding fluorescent reagent emitted from the ultraviolet light source 71 to emit fluorescence. In order to mechanically prevent the electrophoresis gel 101 from being irradiated with wavelengths in the unnecessary visible light region other than the ultraviolet rays for performing image capturing, only the fluorescent color development of the nucleic acid binding fluorescent reagent mixed in the nucleic acid sample is taken. In order to be acquired by 61, a second optical filter 92 (for example, SC-40M manufactured by Fuji Photo Film Co., Ltd.) that mechanically prevents the ultraviolet light derived from the ultraviolet light source from being transmitted to the image photographing means 61 is installed.

  In the first embodiment, the electrophoresis tank 10 is installed immediately above the table mechanism 40, and the image photographing means 61 is mounted on the carriage mechanism 60 that can move on the gel surface. Therefore, the distance between the camera as the image photographing means 61 and the gel as the subject is small, and accordingly the photographing range is also small. Therefore, when photographing a large area gel that exceeds the photographing range of the image photographing means 61, a drive motor (not shown) for driving the table mechanism 40 and a carriage are used using the system control unit 120. By driving the carriage motor 55 for driving the mechanism 60, the table mechanism 40 and the carriage mechanism 60 can be moved to any place on the gel surface, and the image photographing means 61 partially causes the gel to move. The divided images are taken and recorded in the recording device 125 in the system control unit 120. The divided image recorded in the recording device in the system control unit 120 is converted into one electrophoretic pattern image by using the image synthesizing unit 121 provided in the system control unit 120. By using the component ratio converting / reconstructing means 122, the image synthesized by the image synthesizing means 121 is image-divided for each color component, and the color component ratio of each color is determined according to the fluorescence wavelength characteristic of the nucleic acid binding fluorescent reagent. An image reflecting the characteristics of the fluorescent reagent with less noise can be obtained by reconstructing the color component ratio.

  As described above, in Embodiment 1, the state during migration of a nucleic acid sample is photographed continuously or at regular time intervals, and the position of each nucleic acid fraction is determined from the result of electrophoretic imaging. It can be obtained by the minute position measuring means 123, and an optimum migration pattern can be automatically judged to control the voltage applied to the electrode 14 of the electrophoresis tank 10.

  In addition, the image photographing unit 61 photographs the migration pattern of the size marker, which is a reference of the electrophoresis state of the electrophoresis in the electrophoresis support, continuously or at regular time intervals, and is acquired by the system control unit 120. By calculating the migration pattern of the size marker based on the image information thus obtained, it is possible to realize a suitable stop of electrophoresis.

  In addition, since the image photographing unit 61 scans the electrophoresis gel 101, the image of the electrophoresis gel 101 by the image photographing unit 61 can be obtained without being influenced by the gel size and with the same resolution. Thus, there is no need for reduced shooting by the zoom function when the gel size is large as in the conventional image shooting apparatus, and image resolution is not reduced by reduction.

  In addition, since the image photographing means 61, the gel 101 that is the subject, and the ultraviolet irradiation unit 70 are installed at a relatively short distance, the light amount of the ultraviolet light source 71 can be minimized. Conventionally, the amount of light of the ultraviolet light source required about 90 watts, but in the first embodiment, it is possible to take an image with about 15 watts, and it is possible to avoid exposure of the nucleic acid sample to excessive ultraviolet rays.

Next, the gel cutting-out means 62 in this Embodiment 1 which cuts out the separated nucleic acid after electrophoresis for every nucleic acid fraction is demonstrated.
As described above, when a nucleic acid sample carried out from electrophoresis to photographing is used in a later experiment, it is necessary to extract the nucleic acid sample by cutting out a gel.

  In the electrophoresis system according to the first embodiment, first, an electrophoresis pattern is photographed by the method as described above. Based on the electrophoresis pattern image, the nucleic acid fraction containing the target nucleic acid sample is automatically detected, or manually specified by the operator based on the electrophoresis pattern image displayed on the display. To do.

  When the cutting start command is executed by the operator, the carriage mechanism 60 moves to the position immediately above the cutting tool 21 stored in the cutting tool holder 30 on the slide table 45, and the cutting means 62 is moved downward. The cutting tool 21 is gripped.

  Next, based on the electrophoretic pattern photographed image, in order to move the clipping unit 62 to a designated place, the distance to be moved is converted into driving amounts of the table mechanism 40 and the carriage mechanism 60 in the system control unit 120. The drive motor is driven to rotate.

  After the carriage mechanism 60 has moved to the designated position, the cutting tool gripping pin 67 is lowered in the gel installation direction by driving the cutting tool operating motor 56, and the gripping cutting tool 20 is pressed against the gel. Cut out the gel.

  The carriage mechanism 60 moves to the position immediately above the cutting tool holder 30 with the cut gel remaining inside the cutting tool 20, and the cutting tool 21 with the gel placed inside is removed from the cutting means 62 and the cutting tool 20 is removed. Is stored in the cutting tool holder 30, and the cutting operation is completed.

  Further, the table mechanism 40 shifts to a table discharging operation, discharges the electrophoresis tank 10 and the cutting tool holder 30 to the outside of the electrophoresis system, and the operator takes out the cutting tool 20 from the cutting tool holder 30 and pipettes it. The nucleic acid sample placed inside the cutting device 20 is removed together with the gel.

  In the first embodiment, the image capturing unit 61 and the clipping unit 62 are integrated into a unit, and the carriage mechanism 60 is configured. In this way, the image capturing unit 61 and the clipping unit 62 are combined into a unit. The process of cutting out the electrophoresis gel 101 and the process of grasping and storing the cutting tool 20 from the cutting tool holder 30 by the cutting means 62 can be traced in detail by the image photographing means 61 without causing a shadow by the carriage. It becomes possible. Thereafter, the nucleic acid sample can be extracted and collected by an appropriate method such as the method of Vogelstein and Gillespie shown in the background art or the method described in Molecular Cloning.

  In such an electrophoresis system according to the first embodiment, the table mechanism 40 capable of linear movement in the Y-axis direction on which the electrophoresis tank 10 can be mounted, and a part of the gel in the electrophoresis tank 10 are cut out. Cutting device 20, cutting device 62 that holds the cutting device 20 and moves the cutting device 20 in the Z-axis direction perpendicular to the gel surface to cut out the gel, and the cutting device 62 and the image A carriage mechanism 60 that is mounted with an imaging means 61 and can be translated in the X-axis direction on the gel surface; an ultraviolet irradiation unit 70 that can irradiate ultraviolet rays onto the gel 101 in the electrophoresis tank 10 mounted on the table mechanism 40; Image photographing means 61 for photographing the electrophoretic pattern of the gel 101 mounted on the carriage mechanism 60, and turning on / off of the ultraviolet irradiation unit 70 for photographing the electrophoretic pattern And a system control unit 120 for controlling the photographing operation of the image photographing means 61, the voltage applied to the electrophoresis tank 10, and the driving of the table mechanism 40, the carriage mechanism 60, and the cutting means 61. Therefore, it is possible to perform electrophoresis, acquire an electrophoresis pattern image, and extract and collect a nucleic acid fraction separated from a support without the intervention of an operator. It is possible to improve the safety of work related to electrophoresis such as prevention of exposure to ultraviolet rays, increase the efficiency of research work associated with automation of work, and provide a small and inexpensive electrophoresis system.

  3 and 4 show an electrophoresis system according to Embodiment 1 of the present invention, in which an electrophoretic image is divided for each color component, and is reconstructed by changing the ratio of the color component according to the fluorescence wavelength of the nucleic acid fluorescence reagent. FIG. 4 is a diagram illustrating a method for acquiring an image reflecting the characteristics of a fluorescent reagent and a flowchart thereof.

  FIG. 3 shows a 1% agarose gel containing 0.1 μg / ml ethidium bromide as an electrophoresis gel, and 25 ng / μl of restriction enzyme HaeIII hydrolyzed fragment of φX174 phage DNA (Deoxyribonucleic Acids, deoxyribonucleic acid). As a sample, and the electrophoresis patterns of 1353 base pairs, 1078 base pairs, 872 base pairs, 603 base pairs, 310 base pairs, 281 base pairs, and 271 base pair mixtures are used as examples. The manner in which an image reflecting the characteristics of the fluorescent reagent of form 1 is acquired is shown in the figure.

  A color CCD (Mintron 1/4 inch CCD, MTV-54KON) was used for the image photographing means 61, and Fuji Photo Film SC-40M was used for the second optical filter 92 to obtain a color image of electrophoresis ( Step 201 in FIG.

  As shown in FIG. 3, in order to obtain a color image with a CCD, filters of each color component for recognizing a blue component, a red component, and a green component are generally arranged on a CCD element in a Bayer arrangement.

Next, the following operations were executed in the image color component dividing / reconstructing means 122 in FIG.
First, smoothing processing of the image signal taken into the CCD was performed by a median filter (I in FIG. 3, step 202 in FIG. 4).

  Next, a red component signal processing region (R in FIG. 3: wavelength region of about 580 to 750 nm), a green component signal processing region (G in FIG. 3: wavelength region of about 480 to 600 nm), and blue component signal processing of the color CCD. The image was acquired by dividing into regions (B in FIG. 3: wavelength region of about 400 to 480 nm) (step 203 in FIG. 4).

  Next, as shown in the fluorescence spectrum of A in FIG. 8, the fluorescence coloring wavelength region of ethidium bromide is 550 to 750 nm. Therefore, in step 204 in FIG. 4, the fluorescent reagent is ethidium bromide. And the image acquired in the blue component signal processing region which is a color component other than 550 to 750 nm is determined to be a noise component.

  Finally, the image is reconstructed with the image brightness of the red component signal processing region 100%, the green component signal processing region 10%, and the blue signal processing region 0% (step 205 in FIG. 4), and the wavelength of ethidium bromide An image signal corresponding to the characteristics was constructed (step 206 in FIG. 4), and the reconstructed image was displayed on the monitor (step 207 in FIG. 4).

  Thereby, the overexposure of the image at I in FIG. 3 can be reduced, and an electrophoretic image of a nucleic acid with less noise reflecting the fluorescence coloring wavelength characteristic of ethidium bromide can be obtained.

Conventionally, when taking an image using ethidium bromide as a nucleic acid binding fluorescent reagent, the fluorescence maximum wavelength of ethidium bromide is around 600 nm as shown in the fluorescence spectrum of FIG. Since the image becomes a noise component, a red filter is attached so that light of 600 nm or less is not transmitted to the photographing device. However, in the present invention, the noise component is removed by dividing the image for each color component. It is possible to prevent the transmission of only the ultraviolet rays that excite fluorescence in the imaging device.
(Embodiment 2)
FIG. 5 is a diagram showing a support holder 13 having a fluorescent position marker 16 for performing position detection and position control of an electrophoretic image in the electrophoresis system according to Embodiment 2 of the present invention. FIG. 7 is a diagram showing a block configuration of an electrophoresis system according to the second embodiment, and FIG. 7 shows a support holder by performing color component division / color component ratio conversion / reconstruction of an image in the second embodiment. It is a schematic diagram which shows the method of making the 13 fluorescence position markers 16 apparently image non-display.

  In the second embodiment, the table mechanism 40, the slide table 45, and the electrophoresis tank 10 are provided as in the first embodiment. However, the difference from the first embodiment is as shown in FIG. A support holder 13 that can be placed on the support mounting surface 11 of the electrophoresis tank 10 is provided, a fluorescent position marker 16 made of ultraviolet fluorescent paint is smeared on the support holder 13, and fluorescence captured by the image photographing means 61. Based on the position information obtained by the position information calculating means 127 for calculating the position information of the table mechanism 40 or the carriage mechanism 60 from the position information of the position marker 16 and the position information calculating means 127, the table mechanism 40 and the carriage mechanism 60 are driven. The drive control means 128 is provided.

  The fluorescent position marker 16 is a substance that fluoresces the light in the visible light region when irradiated with ultraviolet rays (for example, Lumilite Color or Magic Lumino manufactured by Sinlohi Co., Ltd.), and is one or more on the surface of the support holder 13. Fluorescent position markers are smeared so as to have different symbols or shapes at predetermined locations.

  For example, as shown in FIG. 5, the smear positions of the individual fluorescent position markers 16 are arranged in a matrix so as not to affect the migration of the nucleic acid sample, and the shapes to be smeared or the symbols are different shapes depending on the positions, Or a symbol.

  Further, the position information of the fluorescent position marker 16 for each smeared shape is recorded in advance in the position information calculation means 127, so that the position information of the table mechanism 40 and the carriage mechanism 60 can be calculated.

  With respect to the electrophoresis system according to the second embodiment configured as described above, the operation and action of the electrophoresis system will be described by taking an example of an electrophoresis image that is fluorescently colored with ethidium bromide.

  As the fluorescent position marker 16 on the support holder 13, blue magic lumino (manufactured by Sinloihi Co., Ltd.), which is colorless and transparent under visible light and exhibits blue color under ultraviolet light, is smeared.

  The ultraviolet irradiation unit 70 irradiates the gel as a support with ultraviolet rays, and the image photographing unit 61 photographs the gel.

  The fluorescent position marker 16 smeared on the support holder 13 develops a blue color on the image photographed by ultraviolet irradiation and is photographed by the image photographing means 61 together with the electrophoretic image.

  The shape of the blue fluorescent position marker 16 and the position in the image can be measured, and the position information calculating unit 127 can estimate the positions of the table mechanism 40 and the carriage mechanism 60.

  In this way, based on the position information obtained using the fluorescent position marker 16, the table mechanism 40 and the carriage mechanism 60 can be moved to the target positions by the drive control means 128 via the interface unit 124. .

  Further, the above-described photographing of the blue fluorescent position marker 16, the calculation of the position information of the fluorescent position marker 16, and the drive control of the table mechanism 40 or the carriage mechanism 60 are repeatedly performed at predetermined minute time intervals. The position accuracy of the drive of the table mechanism 40 and the carriage mechanism 60 can be improved, and the images of the plurality of electrophoresis gels 101 photographed by the image photographing means 61 can be synthesized as an integrated image. Even if the state of the band of the nucleic acid sample observed at 101 is smeared, it is possible to suitably perform divided photographing and image synthesis.

  As described above, in the second embodiment, when the fluorescent position marker 16 that develops blue color by ultraviolet rays is smeared on the support holder 13 in advance and the table mechanism 40 and the carriage mechanism 60 are driven, the image photographing means 61 is used. The position control of the table mechanism 40 and the carriage mechanism 60 can be realized based on the photographed image of the fluorescence position marker 16 photographed in Step 1, and positioning means using an expensive driving motor such as a stepping motor is used. Accordingly, it is possible to provide an electrophoresis system comprising a positioning means composed of position information calculation means 126 and drive control means 220 using an inexpensive DC motor.

  Further, in the second embodiment, with respect to the photographed image, the positional relationship with the fluorescent position marker 16 of the nucleic acid fraction is obtained using the position detecting means (position information calculating means 127) using the fluorescent position marker 16 described above. By measuring, it is possible to grasp the position of the nucleic acid fraction in the support 101, thereby performing electrophoresis so that the separation of the biopolymer sample is in the best state. An electrophoresis system that can automatically control voltage application to the electrodes of the electrophoresis tank can be realized.

  Further, the blue fluorescent position marker 16 is used for image composition of electrophoresis and acquisition of image position information. However, since it becomes unnecessary in the electrophoretic image after synthesis and display on the display screen, Without using this, the photographed electrophoretic image is subjected to color division, color component ratio conversion, and reconstruction processing according to the method shown in the first embodiment.

First, an electrophoretic image is photographed by the image photographing means for each photographic range (FIG. 7A).
Next, according to the blue fluorescent position marker, the divided images are combined into one image (FIG. 7B).
Finally, the image of the blue fluorescence position marker is a blue (B) component, distinguished from the fluorescence wavelength region of ethidium bromide located in the green (G) component and the red (R) component. As shown in c), the electrophoretic image is displayed on the display screen.

  After that, as described above, it is possible to easily delete the position marker by performing color division, color component ratio conversion, and reconstruction processing on the captured image. When displaying an image on a display or the like, electrophoresis It is possible to display an original electrophoretic image from which position markers that are not required for image display are deleted.

  As described above, the image acquisition method using ethidium bromide (I) as a nucleic acid binding fluorescent reagent has been exemplified. However, without limitation thereto, SYBR GreenI, SYBR GreenII, SYBR Gold, SYBR Safe, POPO-1, TOTO-1, Even in other fluorescent reagents such as YOYO-1, JOJO-1 or Gel Star, the divided color components are converted into appropriate ratios according to the fluorescence coloring wavelength characteristics and reconfigured to obtain each fluorescence coloring wavelength. It is possible to acquire an electrophoretic image of a nucleic acid with less noise reflecting characteristics.

  Further, in the present invention, the signal processing of the color component by the primary color system is exemplified as the color CCD, but the signal processing by the complementary color system by yellow, cyan, and magenta components can also be adopted.

  Various configurations such as a Bayer array and a stripe array for each color can be adopted as the configuration of the color filter mounted on the CCD for capturing an image in color.

  Further, although the color CCD is exemplified by a single CCD, the color CCD is not limited to this, and it is also possible to perform signal processing with the CCD after dividing it into each color component using a spectral prism or the like.

  In addition, the image capturing means is not limited to a CCD, but a CMOS, a charge injection element (CID), a photodiode, LBCAST (amplified imaging sensor having a lateral embedded charge storage unit, a lateral buried charge accumulator and a sensing transistor array), etc. It is also possible to use a solid imaging element.

  The ratio of the reconstruction ratio of the color component according to the fluorescence wavelength characteristics of ethidium bromide in Embodiments 1 and 2 of the present invention is an example, and the reconstruction ratio depends on the characteristics of various CCDs, CMOSs, etc. The ratio can be arbitrarily changed.

  Further, the smoothing processing of the image signal captured by the image photographing means is not limited to the median filter, and various smoothing signal processing such as a moving average filter or a weighted average filter can be performed.

  Furthermore, when using the electrophoresis system of the present invention, it is desirable to install the apparatus in a dark box so as to avoid external light in order to take a fluorescent color image by an excitation light source.

  The electrophoretic system according to the present invention is an electrophoresis system capable of performing a series of gel electrophoresis, photographing an electromigration pattern, and cutting out a nucleic acid sample after electrophoresis. It is possible to provide a small and inexpensive device that acquires electrophoretic images of nucleic acids with low noise reflecting the wavelength characteristics, and is useful in the technical fields related to electrophoresis, which are commonly used in biopolymer analysis. .

The perspective view which showed the outline | summary inside the electrophoresis system by Embodiment 1 of this invention 1 is a block diagram of an electrophoresis system according to Embodiment 1 of the present invention. The conceptual diagram which shows the division | segmentation for every color component of the electrophoresis image acquired by electrophoresis, and a reconstruction in the electrophoresis system by Embodiment 1 of this invention The flowchart figure which shows the division | segmentation for every color component of the electrophoresis image acquired by electrophoresis, and a reconstruction in the electrophoresis system by Embodiment 1 of this invention. The perspective view which showed the electrophoresis support body which gave the fluorescence position marker utilized for the electrophoresis image synthesis | combination in the electrophoresis system by Embodiment 2 of this invention, and support body positional information acquisition Block configuration diagram of an electrophoresis system according to a second embodiment of the present invention Schematic diagram showing a fluorescent position marker non-display method in electrophoretic image display in an electrophoretic system according to Embodiment 2 of the present invention. Fluorescence spectra of various nucleic acid binding fluorescent reagents

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electrophoresis tank 11 Support surface 13 Support body holder 14 Electrode 16 Fluorescence position marker 20 Cutting tool 21 Upper connection part 30 Cutting tool holder 40 Table mechanism 42 Table mechanism power transmission part 45 Slide table 55 Carriage mechanism operation motor 56 Cutting tool Operation motor 58 Gear 60 Carriage mechanism 61 Image photographing means 62 Cutting means 63 Linear motion shaft 64 Lead screw 65 Cutting tool gripping pin 66 Screw nut 70 Ultraviolet irradiation unit 71 Ultraviolet light source 91 Optical filter 101 Electrophoresis gel 110 Power supply unit 120 System Control unit 121 Image compositing means 122 Image color component dividing / reconstructing means 123 Nucleic acid fraction position measuring means 124 CPU
DESCRIPTION OF SYMBOLS 125 Interface part 126 Recording apparatus 127 Position information calculation means 128 Drive control means 201 Acquisition of a color image 202 Smoothing process of an image signal 203 R, G, B component division | segmentation of an image 204 Color recognition wavelength characteristic recognition of a fluorescent reagent and a color reagent 205 Distribution and reconstruction of RGB image components according to the color development wavelength characteristics of the fluorescent reagent and the color reagent 206 Construction of an image signal according to the color development wavelength characteristics of the fluorescence reagent and the color reagent 207 Image display

Claims (6)

In an electrophoresis system for separating and analyzing biopolymer samples,
An electrophoresis tank for performing electrophoresis of the biopolymer sample using a support;
A voltage applying means for applying a voltage to both ends of the support provided in the electrophoresis tank and causing the biopolymer sample to undergo electrophoresis;
Image photographing means for photographing the result of electrophoresis of the biopolymer sample;
From the image photographed by the image photographing means, calculating position information of the biopolymer fraction in the support, and having a cutting means for cutting out the biopolymer fraction separated by the support,
An electrophoresis system capable of performing a series of processes from the start of electrophoresis of the biopolymer fraction to the extraction and collection of the electrophoretic biopolymer sample fraction,
The image photographing means for photographing the image of the electrophoresis result is obtained by dividing the image for each color component, and then changing the color component ratio according to the coloring wavelength or the coloration wavelength of the image. Reconstruct the image,
An electrophoresis system characterized by that. The electrophoresis system according to claim 1, wherein
A position marker for synthesizing a plurality of images of electrophoresis results dividedly photographed by the image photographing means, or for acquiring position information of the images of the respective electrophoresis results on the support. It is something other than the color development wavelength or coloration wavelength region of the electrophoresis result image,
When the electrophoresis result image is divided for each color component, the position marker is not used when the electrophoretic image is reconfigured by changing the color component ratio according to the color development wavelength or the coloration wavelength of the image. Displayed,
An electrophoresis system characterized by that. The electrophoresis system according to claim 1, wherein
A filter that restricts the light wavelength taken into the image photographing means for photographing the image of the electrophoresis result according to the coloring wavelength of the image or the coloring wavelength, a fluorescent reagent having the coloring wavelength or the coloring wavelength, Or without using the spectral characteristics of the color reagent, a visible light wavelength region transmission filter,
An electrophoresis system characterized by that. The electrophoresis system according to claim 1, wherein
After the electrophoresis result image is acquired by dividing it into at least three types of color components, the image of each color component is reconstructed into an image of each color component different from the above according to the coloring wavelength or coloration wavelength of the image And acquire an electrophoretic image,
An electrophoresis system characterized by that. The electrophoresis system according to claim 4, wherein
The electrophoresis result image is initially acquired in color so that the electrophoresis result image can be divided into at least three color components.
An electrophoresis system characterized by that. The electrophoresis system according to any one of claims 1 to 5,
The image photographing means for photographing an image of the electrophoresis result is a solid-state photographing element composed of a color type charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS) device, or a photodiode, and the electrophoresis result Digitize and acquire images of
An electrophoresis system characterized by that.