Studies On Chromosomes And Mitoses Of BmN Cells And Primary Culture Of Bombyx Mori's Embryonic Cells

The technique of insect cell culture ,one of the bases of cell engineering ,is a valuable method of modern experiment biology. It was applied widely to various fields of biology, medicine and agriculture.As engineering cells in the insect baculovirus expression system , insect cells have close relationship with to transform and expression efficiency in the expression system. Therefore .studies on insect cells are very useful for the exploitation of the expression system. Although compared with the other insect cell expression systems, the expression system which uses silkworm ,bombyx mori, as bioreactor is very meaningful to study for so many merits of it. There are problems existing in the transform and expression efficency of silkworm cell line . So, the application of the silkworm cells lines is not so extensive as that of the other cell lines, e.g. Sf9 ,Sf21. Thus, strenghtening the basic biology theorical study of the engineering cell and seeking the better cell system for the baculovirus of silkworm are current needs for the study of silkworm expression system.The study for basic biology of silkworm cell is urgent to strengthen.Cell culture in vitro is a feasible and effective method to the study. Meanwhile,the development of this study can not only provide the excellent study system for the cytobiology but also is significant to the exploitation and utilization of the resources of silkworm.This dissertaion, on the basis of the other studies, on the one hand , researched and analysed the chromosomes and mitoses of the cell line-BmN, which is widely used in the silkworm baculovirus expression system as an engineering cell .On the other hand,the dissertation attempted to explore establishment of the new silkwormembryoni cell line by primary culture. At the same time,in the study the types of cells and tissues emerged in the silkworm embryonic primary culture were observed and researched. The reasults are summed up as following:1 The study on chromosomes and mitoses of BmN cellsThe cell line, BmN,is a silkworm cell line widely used in silkworm molecular genetics,cell engineering,gene engineering and baculovirus expression system but whose genetics and cytobiology studies are nearly untouched.The chromosomes and mitoses of the BmN cells are researched by the air-drying method and culturing cells on cover glasses . The reasults are summed up as following:(1) The more metaphase chromosomes of BmN cells and moderately contraction can be obtained by air-drying after cultured at the colchicine concentration 1.0 u g/ml, 28 "C , for 6-9h.(2) The chromosomes of BmN cells showed the typical characteristics of lepidoterati insects. Chromosomes of matephase without apparent centromere are short pole-like and pellet-like. The BmN cells are multiploidy and heteroploidy so highly that in which the diploid was few and far between, and multiploid was so much that came to 90% . Even there were 533 chromosomes in one cell.(3) The chromosomes obtained by air-drying and chromosomes from the silkworm genital gland are similar in shape.But the numbers and the length of the chromosomes are obviously different.The chromosomes obtained from the genital gland have little difference in length , while the chromosomes of BmN cell are different in length very much.(4) Although the majority of BmN cells' mitoses are normal mitoses, there are still some abnormal phenomena found such as analogous amitoses, mitoses in multiploid cells and endomitoses.2. The primary culture of silkworm embryonic cells(1) This dissertation took silkworm blastokinesis embryo as the materials of primary culture and found a better method of fragment embryo to primary culture by comparing the methods of fragment embryo that mincing embryo by scissors and digest embryo by trypsin after mincinging. That is the latter. By this method ofprimary culture, cells and tissues could not only subsist for 11 months and more in vitro, but also be subcultured.These works lay a foundation of the establishment of silkworm e...