Biological effect of extreamely low frequency magnetic fields on microorganisms

极低频磁场（ELF）的生物效应尚不清楚。流行病学研究表明，接触极低频与几种癌症的发病率之间的相关性很弱，但也有负面研究报告。近年来的研究表明，ELF可诱导人黑色素瘤细胞发生突变，本文研究了60 Hz和500 mT的ELF对酿酒酵母和多小核草履虫的生长和突变频率的影响。研究了几株酿酒酵母（野生型和辐射敏感突变体，rad）和多微核假单胞菌的生长速率，但未观察到生长的显著差异。我们还试图分离出对ELF敏感的S.在筛选了10000个突变酵母细胞后，获得了两个对极低频磁场敏感的酵母细胞，并对它们进行了检测，同时对多微核拟单胞菌在极低频磁场和静磁场下的行为进行了研究，结果表明：当多微核拟单胞菌暴露于极低频磁场时，多微核拟单胞菌上升到比色皿中，并停留在那里，当暴露停止时，细胞又开始自由游动。现在我们来分析详细的机制。

The biological effects of extremely low frequency magnetic fields (ELF) are not clear. Epidemiological studies have shown weak correlations between exposure to ELF and the incidence of several cancers, but negative studies have also reported. Recent study showed human melanoma cells were induced mutations by ELF.In this work, We studied the effect of ELF of 60-Hz and 500 mT on the growth and the mutation frequency of the budding yeast S.cerevisiae and the ciliate Paramecium multimicronuncleatum. The growth rate of several strains of S.cerevisiae (wild type and radiation sensitive mutants, rad) and P.multimicronucleatum were examined but no significant differnce on growth were observed. We have also tried to isolate the ELF sensitive mutants of S.cerevisiae. Two ELF-sensitive candidates were obtained after screening ten thousand mutated yeast cells and now we have been examining them.Moreover, the behavior of P.multimicronuncleatum under the ELF or static magnetic fields were examined.When P.multimicronucleatum was exposed with ELF magnetic field, P.multimicronucleatum went up to cuvette, and remained there, and when exposure was stopped the cells swam randamly again. Now we are going to analyze the detail mechanism.