The Proteomics Research Of Toxicity Mechanism Of Resistance To Cadmium In Lactococcus Lactis Subsp. Lactis

Now people’s living standard has been greatly improved, Health, of course, also willmore and more get the attention of the broad masses of the people. But due to the peoplefor the extraction of heavy metal smelting processing and commercial manufacturingactivity is increasing, variety of heavy metals such as lead, mercury, cadmium, cobalt, etcinto the atmosphere,water and soil.Thus caused serious environmental pollution.Heavymetals is in a variety of chemical state or chemical form，When it enters the environmentor a reserved ecosystem then will be accumulated and migrated and resulting in harm.Such as when heavy metal wastewater was discharged, even if the concentration is small,can also be in algae and sediment accumulation, to be surface adsorbed by fish andshellfish,then enriched the food chain,causing nuisance.Biological adsorption method is developing rapidly in recent.It is also a moreadvanced method of removal of heavy metals. But, the study of bioremediation of heavymetal pollution at present in food or food raw materials and production which in theprocess of transportation, in addition to saccharomyces cerevisiae belongs to foodmicrobiology,there were seldom other food microorganism be studied. However, recentlypeople are already more and more focus on recognized probiotic in the food-lactobacillus,at home and abroad, about the use of lactobacillus to remove heavy metal ions in food anddrinking water pollution is in the stage of preliminary study now, but it still shows thefeasibility and potential.This article first cultivated and domesticated a strain of Lactococcus lactissubsp.lactis which screened from kimchi that resistance to cadmium, and with it as rawmaterials purified cytoplasmic protein. This step is to provide raw material for thefollowing difference proteomics research. Using proteomics techniques, by using themethod of two-dimensional gel electrophoresis to build the protein profiles of Lactococcuslactis subsp. lactis, compared to the control group (not adding Cd2+) as well as theexperimental group (Cd2+mass concentration of50mg/L) of the protein, to identifydifferentially expressed proteins, and then proceed mass spectrum identification. Byreverse transcription-polymerase chain reaction (RT-PCR) technique and quantitative reverse transcription polymerase chain reaction (qRT-PCR) amplificated the interestprotein target fragment that have differences. This is for further research for molecularmechanism of the resistance to cadmium in this Lactococcus lactis subsp. lactis,lay afoundation for eventually determine the related cadmium resistance genes. The specificresearch results are as follows:1Identified with the MRS culture medium formula when added Cd2+.2After domestication operation we determined the maximum resistance of cadmiumconcentration is200mg/L in Lactococcus lactis subsp. lactis.3We determined the Lactococcus lactis subsp. lactis is a bacteria which broadspectrum resistance of heavy metal, for Pb2+, Cr(VI),Ag+, Ni+, Mg2+, Cu2+, Mn2+, Mn7+,Na+,Ca2+, the Lactococcus lactis subsp. lactis has high tolerance, just the tolerance forCu2+and Ni+is low.4Successfully established the method of two-dimensional gel electrophoresis for theLactococcus lactis subsp. lactis, analysis and mass spectrum identification, received12kinds of different proteins, and the expression of the12kinds of protein is increase,thefunction of the GO clustering analysis of the12kinds of protein can be divided into sixtypes: cellular stress response, carbohydrate metabolism, small molecular metabolism,nucleic acid metabolism, protein metabolism, cell proliferation.5Through the qRT-PCR we verified the related genes to cadmium of theLactococcus lactis subsp. lactis is ykiE, ykiE genes associated with iron-sulfur clusteranabolism, when exposured to the Cd2+stress the gene performanced for raisingexpression,the raising expression of ykiE may better to restore function of ferredoxin andredox enzyme, to remove the cell oxidative damage under Cd2+stress of the Lactococcuslactis subsp. lactis which generated by the large amount of active oxygen resistance tocadmium.