Title of Invention	''AN ELECTROPHORETIC GEL STRIP CUTTER SYSTEM''
Abstract	An e1ectrophoretic gel strip cutter system comprising a guide (1) and an e1ectropharetic gel strip cutter assembly (2) said assembly (2) having a holder (5) and twin surgical blades (3) and (4) held to said holder.

Full Text

FEILD OF INVENTION This invention relates to a electrophoretic gel strip cutter system. PRIOR ART OF THE INVENTION; Pulsed-field gel e1ectrophoresis, herein after referred as PFGE, technique has encouraged attempts to study DNA damage and repair in individual chromosomes of yeast or in high molecular wt DNA strands. It is well understood by those, who are conversant with the art that DNA damage, as referred herein above, generally means breaks in DNA strands leading to alteration in size and/or shape and/or conformation of DNA. Such DNA strand breaks are induced by DNA damaging agents. It is well understood by those who are conversant with the art that DNA damaging agents, as referred herein above, generally means, radiations alone or in combination with DNA binding ligands, photosensitisers or some of the anticancer drugs eg. Bleomycin which induce DNA strand breaks. The DNA exposed to DNA damaging agents, as referred herein above, is referred as 'treated DNA', herein after. To study such effects, the DNA samples are prepared and developed by such known methods. The samples are electrophoresed using PFGE technique and photographed after staining and destaining the gels. Such developed photographs/ photonegatives are used to estimate the DNA damage and repair, preferably after scanning under the densitometer. In the pulsed field electrophoresed agarose gels, thus obtained, the DNA bands, each representing a chromosome, are possilble to be resolved clearly in untreated samples only. However, in 'treated DNA' as referred herein above, the resolution of bands decreases and the smear appears, particularly in the lower molecular weight range. The appearance of smear limits the analysis of damage to only clearly resolved bands preferably in the high molecular weight region. Therefore, instead of quantifying DNA damage and repair of all the bands, by such known methods, using such known techniques and by adopting such known devices is' restricted to/quantitatioh of DNA damage and repair to only clearly resolved bands of high molecular weight region only. Another disadvantage of the smear thus appeared particularly in the low molecular weight region by such known methods using such known techniques and by adopting such known devices is that quantification of different types of damage, more precisely quantification of double strand breaks is not possible. Therefore quantification is limited to estimation of average DNA damage and repair based on alterations in the intensity ratios of DNA bands. Such limitations of such known methods using such known techniques by adopting such known devices, as stated herein above, that is being able to quantify only average DNA damage and repair in clearly resolved bands of high molecular weight only rather than being able to quantify The DNA double strand breaks or reapir i.e. different types of DNA damage or repair in all the chromosomal DNA bands individually, are mainly due to the drawbacks of the known electrophoretic gel cutters. The known electrophoretic gel cutters have a single blade to generate a single cut in the gel as referred herein above. These known gel cutters are mainly used to cut the gel into two or more number of pieces, herein after referred as gel pieces. Only one cut is made at a time with the help of single blade cutter. Such gel pieces are of irregular size, shape and of different length and width because they are generated with the help of known gel cutters by free hand movement. The chances of irregularity in shape and size increases when a cut larger than approx. 1 cm length is made. The known electrophoretic gel cutters, when used with the known PFGE techniques results in the formation of smear on the chromosomal bands, after it is irradiated as stated v herein above, which in turn can not be resolved to separate the DNA fragments from the chromosomal bands. Still another disadvantage of formation of smear by use of known electrophoretic gel cutters with known PFBE technique is that the formation of such smear does not allow to identify the belongingness of the smear of DMA fragments with individual or particular or specific chromosome. Still another disadvantage of formation of such smears by use of such known e leetrophoretic gel cutters with known PFGE technique is that the formation of such smear does not allow to resolve the mixture of DNA fragments, according to their belongingness to the individual or specific chromosomal band, obtained after irradiation and which in turn would have been separated after pulsed field gel electrophoresis. The main disavantage of such irregular shape gel pieces generated by known such e1ectrophoretic gel cutters, as referred herein above, is that these gel pieces have uneven edges and therefore, do not fit }nto the slots generated in the gel for electrophoresis. These gel pieces generated by known gel cutters are therefore, unsuitable for further developing the assay to study the in-vitro DNA damage to individual or say specific chromosome, irrespective of their molecular weight which in turn results in the disadvatages/ drawbacks of the prior art, as described herein above in the foregoing description, that is limiting the quantification only to quantitation of average DNA damage and repair of individual bands resolved in the high molecular weight range only. Therefore, the known electrophoretic gel cutters, as known in the prior art, do not permit to record the mobility of each individual chromosome or its DNA fragments to estimate the DNA damage and repair in individual chromosomes. Still another disadvantage of such gel pieces generated by the eleetrophoretic gel cutters, known in the art, is' that opposite ends of such gel pieces are not parallel, thereby causing loss of DNA samples in atleast some of the DNA bands therby making them unsuitable for further development of assay to study specific DNA damage and repair in all the individual chromosomal bands irrespective of'their molecular weight. Still another disadvantage of such known gel cutters is that, there are no means to generate a parallel strip of gel with accurately adjusted width which in turn may result in damaging the slots of gala rendering the gel slots, unsuitable for further development of the assay. Still another disadvantage of such known cutters is that there is no provision of a guide to adjust the length of gel strip with respect to the length of gel slot generated to hold the sample for further development of already developed assay. The further disadvantage of such known gel cutters is that there is no provision to adjust the angle to hold the cutter while cutting the gel which in turn makes the gel cutting a very inconvenient process. The further disadvantage of such known cutters i r5 that to generate a gel strip one has to cut very slowly and two times rendering the entire process a time consuming process. Since the entire operation is generally performed in presence of UV (ultra-voi1et)-light, as known to those who are conversant with the art, the user is exposed to the UV-light for much longer period. Such an occupational exposure to UV-light is known to cause mutations which could result in c ancers. OBJECTS_OF_THE_INVENTION: The main object of the present invention is to propose electrophoretic gel strip cutter system, the device comprising of a guide and twin-blade gel strip cutter, wherein the device obviates the disadvantages and limitations of the prior art. Another object of this invention is to propose an e1ectrophoretic gel atrip cutter sy»tem which can permit the analysis and quantification of the actual or specific DNA damage to all the individual chromosomes. Yet another abject of the present invention is to propose for an electrophoretic gel strip cutter system which can permit to resolve the smear to separate the DNA fragments, particularly which can permit to identify the be longingness of the smear of DNA fragments to the individual or particularly or specific chromosomal DNA band, more particularly, which can permit to resolve the mixture of DNA fragments, according to their belongingness to the individual or specific chromosome obtained after treating the untreated DNA embeded in the agarose gel, which in turn has been already obtained by using the known such eleetrophoretic gel cutters with known such PFGE technique. Still another object of this invention is to propose a system, which can generate gel strip of even edges which can be inserted into the gel slots generated through improved single strip electrophoresis comb to hold the sample for further developing the assay, more particularly the chromosomal prof.ile, which has already been developed once by using the known e1ectrophoretic gel cutter with PFGE technique. Still further object of this invention ia to propose a system which can generate gel strips with parallel opposite ends so that there is no loss of DNA samples from either of the chromosomal DNA bands and thereby permitting to record the mobility of each individual chromosome or its fragments already separated by using known e1ectrophoresis gel stip cutter with known PFGE technique, to estimate specific DNA damage in each chromosome induced by the DNA damaging .agents. Still further object of this invention is to propose a system which can generate gel strips with accurately adjusted width, which in turn does not damage the gel slots generated to hold the sample,, thereby allowing the further development of the assay. Still further object of this invention is to propose a system which can generate gel strips of known length with respect to the length of the gel slot generated to hold the sample. Still further object of this invention is to propose a system which can generate parallel gel strips of known width and length, having smooth and even edges in a single move thereby enabling speedy generation of gel strips, which in turn minimises the exposure time of the user to the harmful UV—light which can cause mutations, and cancer. BRIEF DESCRIPTION OF THE INVENTION According to this invention there- is provided an e lee. trophoret:i.c gel strip cutter system comprising a guide (I) and an electrophoretic gel strip cutter assembly (2), said assembly (2) having a holder (5) and twin surgical blades (3) and (4) held to said holder. The present invention discloses an electrophoretic gel strip cutter system for elec.trophoresis and the method of use thereof, particularly an electrophoretic gel strip cutter for horizontal gel electrophoresis and the method of use thereof. The device primarily comprises of a long UV (ultra-voilet) transparent polyacrylamide table, herein referred as "guide" and an assembly of two surgical blades mounted on a holder, herein after referred as the electrophoretic gel strip cutter or just the "strip cutter". The blades are mounted in such a way that distance between the blades is fixed. The cutting edges of the blades are at a convenient angle from the gel surface and the surface of the guide. The top of the guide is a rectangular flat block supported by two rectangular blocks at the two ends which serve as stands at two side ends, all being preferably made of UV-transparent polyacrylamide. The width of the two side ends preferably matches with the width of the rectangular block at the top. The height of the guide (.1) matches with the height of the blade. The width of the guide (i) top matches with gap between the blade. The top-side of the guide (1) could be graduated or ungraduated depending upon the requi rements The gel strip cutter assembly (2) mainly comprises of a holder and twin surgical blades which are tightly screwed to the holder through the holes provided in the upper part of the holder. The holder could be of any polymeric material or may be metallic. The lower part of the holder could be circular tapering down or tapering up or rectangular tapering up or tapering down or may be right cylindrical shape or of any desired shape. DESCRIPTION OF THE FIGURES The detailed constructional features of an eleCtrophoretic gel strip cutter and its method of working as disclosed in the present invention would now be illustrated with the help of accompanying figures wherein: Fig 1 : Shows the guide and the electrophoretic gel strip cutter Fig 2 : Shows e1ectrophoretic gel strip cutter Fig 3 : Shows non-assembled e1ectrophoretic gel strip cutter Fig 4 : Shows the details of guide Fig 5 : Shows the method of use of electrophoretic gel strip cutter DETAILED DESCRIPTION OF INVENTION According to the present invention, electrophoretic gel strip cutter system as shown in fig 1, comprises mainly of two parts namely table-shaped guide (1) having flat rectangular shaped top of narrow width made of transparent polymer, and electrophoretic gel strip cutter assembly (2). According to preferred embodiment the guide(l) is preferably made of UV transparent polyacrylamide. Referring to Fig (2), (3) and (4) are the two surgical blades. (5) is a holder referred to as handle. The surgical blades (3&4) are tightly screwed on to the holder. (5) with two screws (6) and (7). The angle(8) between blade and the handle(5) can be conveniently adjusted between 90 to 180°. The fig 3(a) and 3(b) show further details of the electrophoresis gel strip cutter assembly(2). The portion marked 'X' of the handle(5) can have different shapes like circular tapering down as shown in fig 3(a). It could similarly have shapes like circular tapering up, right cylindrical shape, papallelopiped shape etc. Similarly portion 'Y' of the handle also could have any shape. However, according to preferred embodiment the potion marked 'Z' of handle(5) has preferably the shape as shown in fig 3(a). The edge-line(a) of the portion "L" of the handle(5) is such that when the surgical blades(3) & (4) are screwed to the handle(5) the non-sharp edges of the surgical blades (3) & (4) are along the edge-1ine(15) of the handle. The surgical blades(3) & (4) are screwed to the handle(5) with two screws(6) and (7) (fig 2) through the two holes (1O) & (11) in the handle(5). Additional hole(12) is provided for varying the angle(B) between the handleO) and the blades (3)&(4). According to preferred embodiment, the edge line(13) of the portion 'Z' of the handle is such that it could be smoothly moved over the table(2) as shown in fig(5). The surgical blades(3) and (4) have slits (14) & (15) respectively through which these blades (3&4) are fixed to the handle(5) with screws (6) & (7) passing through holes (10) & (11) in the handle (5). The fig 4 shows the details of the guide (1). The top rectangular block(16) of the guide (1) has a length preferably between 12 cm to 18 cm and has preferred thickness between 2mm to 5mm. The two side supporting rectangular blocks (17) & (18) have height in the preferred range between 15mm to 30mm. Preferably the top rectangular block(16) of the guide(l) is graduated to help in cutting the gel strip of desired length. The width (19) of the guided) matches the distance between the two surgical 'blades(3) & (4). The height of the two sides (17) & (18) is such that when the quide is placed over the gel and the electrophoretic qel strip cutter is elided over it. (as shown in fig 5) the blades pierce through the full depth of the gel and cut a straight of the gel and cut a straight, rectangular strip of qel In one single movement of strip cutter over the quide (.1 } . Method of Use The fiq (5) shows. the working of the electrophoretic gel strip cutter assembly. The guide? (1) is placed over the gel where in gel-strips in the required lanes are to be cut. The gel-strip cutter (2) is placed over the quide (i) as shown in fig (5) at the desired position. The twin surgical blades (3) and (4) are then moved along the length of the top block (16) of guide (i). Thereby cutting a straight, rectangular gel-strip with smooth parallel ends. These smooth straight gel-strip fit-in smoothly in the gel-slots generated by a gel-slot generator. Being straight, and smooth, these qel.--str.ips do not damage the edges of gel slots. It is to be understood that, the present invention is susceptible to modifications, adaptations by those skilled in the art. Any such modifications, adaptions on equivalents are intended to be within the scope of the present invention as set forth by the claims made herein:- WE CLAIM: 1. An electrophoretic gel strip cutter system comprising a guide (I) and an electrophoretic gel strip cutter assembly (2), said assembly (2) having a holder (5) and twin surgical blades (3) and (4) held to said holder. 2. An electrophoretic gel strip cutter system as claimed in claim .1. wherein the lower part of the holder (5) can has an edge (9) such that non-sharp Bide of the twin blades (3) and (4) is along side the edge (9). 3. An electrophoretic gel strip cutter system as claimed in claim .1. wherein the edge (13) of the holder is such that the gel strip cutter sits on the top block (16) of the guide (i) enabling smooth movement over guide (1). 4. An electrophoretic gel strip cutter system as claimed in claim .1. wherein the width of the rectangular- block forming the top (16) of the guide (1) is same as the distance between the two surgical blades (3) and ( 4 ) . 5- An electrophoretic gel strip cutter as claimed in claim 1 wherein the width of the top rectangular block (16) of the guide (1) is preferably between 12 cm to 18 cm. 6. An electrophoretic gel strip cutter as claimed in claim 1 wherein the height of the two side supports (17) and (18) of the guide (I) corresponds to the height of the twin blades when gel strip cutter is placed over the guide (I). 7. An electrophoretic gel strip cutter as claimed in claim 6 wherein the height of two side supports (17) and (18) of the guide (1) is preferably within 15 mm to 30 mm. 8. An electrophoretic gel strip cutter as claimed in claim i wherein guide (i) is made of transparent polymeric material, preferably of UV (Ultra-vox let )-• t. r a n s p a r e n t p o 1 y a c r y 1 a m i d e . 9. An electrophoretic gel strip cutter substantially as herein described and illustrated.

Documents:

357-DEL-1998-Abstract.pdf

357-del-1998-claims.pdf

357-del-1998-correspondence-others.pdf

357-del-1998-correspondence-po.pdf

357-del-1998-description (complete).pdf

357-del-1998-drawings.pdf

357-del-1998-form-1.pdf

357-del-1998-form-19.pdf

357-del-1998-form-2.pdf

357-del-1998-form-3.pdf

357-del-1998-form-4.pdf

357-del-1998-form-6.pdf

357-del-1998-gpa.pdf

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