The Effects Of He-Ne Laser And Enhanced Ultraviolet-B Radiation On PCNA In Wheat Seedlings

With the development of modern science and technology,human activities have caused more serious effects on environmental pollution.Especially the release of chlorofluorocarbons and other compounds,the destruction of ozone layer in the stratospheric cause the enhancement of ultraviolet-B radiation on the ground from the sun light,which cause great harm to the living things on the earth.High dose of UV-B cause the inhibition of plant growth and the effect of physiology and biochemistry as well as genetic materials.As we all known,the laser as a physical factor has the ability to promote the growth and development of plants,physiological and biochemical,breeding of metabolic.The research group find that He-Ne laser can repair the damage of the enhance UV-B radiation on the wheat.Wheat as one of the most important source of human food has very important significance to study its response after enhanced UV-B radiation and relieve that stress by He-Ne laser.PCNA(proliferation cell nuclear antigen)protein has a very important role in cell cycle,is a kind of cell proliferation related protein,which is composed of 261 amino acid residues and the relative molecular weight of about 30 KD.PCNA is a synthesis of proteins in the nucleus.PCNA's main function of PCNA is work on DNA polymerase,and PCNA of interaction with DNA synthesis in cell cycle regulatory proteins,which influence the replication of DNA and chromosome assembly process.So the study of PCNA,further reveal the molecular mechanism of cell cycle regulation,mitosis is necessary.This research mainly use the He-Ne laser(632 nm,5 mw·mm-2 2 min·d-1)and the enhanced UV-B(10.08 KJ·m-2·d-1)radiation to deal with wheat(Triticum aestivum,CV)seedlings and set up four different treatment groups: enhanced UV-B group(B),control group(CK),He-Ne laser group(L),the composite treatment group of enhanced UV B radiation and He-Ne laser(BL).The changes of the content of the wheat leaf PCNA1 and PCNA2 in the four groups was tested by using semi-quantitative PCR amplification techniques.Next,use SDS polyacrylamide gel electrophoresis(SDS-PAGE)and protein immunoblot technology(Western Blot)to respectively carry the preliminary separation and preliminary identification of the PCNA protein in wheat cells.At the same time,analyze the relative contents change of PCNA in wheat seedling in the four different groups by the Quantity One software and explores the location distribution of PCNA protein and chromosome of wheat root tip meristematic zone cells in the cell cycle by using indirect immune-fluorescence labeling technology.Beyond that,the relationship between PCNA protein in wheat root tip cell and the abnormal mitosis are discussed in this paper,the results show:1.Preliminarily determines wheat exist the PCNA protein and the molecular weight of it is about 30 KD protein by SDA-PAGE and Western Blot technique.And compare with four different treatment groups,we find that wheat PCNA protein content of UV-B treatment group reduce,and the content of He-Ne laser group raised.2.The change of the relative expression level of wheat leaf PCNA1 and PCNA2 in four groups were tested by Semi-quantitative PCR amplification.And compare between the four groups,we find that the expression of PCNA1 and PCNA2 in enhanced UV-B group are the lowest,the relative expression of PCNA1 and PCNA2 in He-Ne group are highest,the expression in the control group just below the He-Ne group and the expression of the composite treatment group of enhanced UV-B radiation and He-Ne laser(BL)is higher than UV-B group high,but are lower than the other three groups.3.PCNA protein in wheat root tip cell in different period show different distribution,which is confirmed by immune-fluorescence labeling technology.And intensity of PCNA protein fluorescence in different historical periods in CK group is obviously higher than that the UV-B group through comparing.In addition to,chromosome of split phase in UV-B group occur chromosome aberration phenomenon in the prophase,metaphase,anaphase and telophase,and cell division of CK group is no abnormal phenomenon.