地球上所有生物的繁衍生息和進化都是在地磁場環(huán)境伴生中進行的。因此,，認(rèn)識地磁場對生物的影響是地球科學(xué)的重要研究內(nèi)容,。最近，美國出版的《生物物理學(xué)雜志》（Biophysical Journal）和《地質(zhì)微生物學(xué)雜志》（Geomicrobiology Journal）雜志發(fā)表了中國科學(xué)院地質(zhì)與地球物理研究所地球深部結(jié)構(gòu)與過程研究室潘永信研究員與合作者在此研究領(lǐng)域的兩篇論文,他們綜合分子生物學(xué),、電子顯微鏡技術(shù),、巖石磁學(xué)等交叉學(xué)科手段，系統(tǒng)研究了趨磁細(xì)菌MYC-1的磁學(xué)性質(zhì)和趨磁游泳特性,。
研究表明,，趨磁球菌MYC-1屬于α-變形菌綱的一株新型趨磁細(xì)菌，它們在細(xì)胞內(nèi)合成1條磁小體鏈,，鏈的排列與細(xì)胞運動器官鞭毛具有一定的夾角,；合成的磁小體為單疇磁鐵礦。根據(jù)旋轉(zhuǎn)磁場游泳行為計算獲得單個細(xì)胞磁矩為1.8×10-15 Am2,。他們發(fā)現(xiàn)無論是在直線場還是旋轉(zhuǎn)場,，MYC-1均為螺旋前進，而非直線運動,，且隨磁場強度增加,，趨磁游泳速度（VM，平行磁場方向）降低,，這項發(fā)現(xiàn)對趨磁細(xì)菌游泳速度隨外場強度增加而單調(diào)增加的傳統(tǒng)觀點提出了挑戰(zhàn),。研究結(jié)果反映出趨磁細(xì)菌與地磁場具有長期協(xié)同進化的特點，當(dāng)磁場強度高于地磁場時趨磁游泳速度受到抑制,，這為揭示地磁場對生物的影響,、細(xì)菌礦化，以及認(rèn)識生物的趨磁性質(zhì)和磁導(dǎo)航具有重要科學(xué)意義,。（生物谷Bioon.com）
生物谷推薦原始出處：
Biophysical Journal Volume 97 August 2009 986–991
Reduced efficiency of magnetotaxis in magnetotactic coccoid bacteria in higher than geomagnetic fields.
Pan Y, Lin W, Li J, Wu W, Tian L, Deng C, Liu Q, Zhu R, Winklhofer M, and Petersen N
Magnetotactic bacteria are microorganisms that orient and migrate along magnetic field lines. The classical model of polar magnetotaxis predicts that the field-parallel migration velocity of magnetotactic bacteria increases monotonically with the strength of an applied magnetic field. We here test this model experimentally on magnetotactic coccoid bacteria that swim along helical trajectories. It turns out that the contribution of the field-parallel migration velocity decreases with increasing field strength from 0.1 to 1.5 mT. This unexpected observation can be explained and reproduced in a mathematical model under the assumption that the magnetosome chain is inclined with respect to the flagellar propulsion axis. The magnetic disadvantage, however, becomes apparent only in stronger than geomagnetic fields, which suggests that magnetotaxis is optimized under geomagnetic field conditions. It is therefore not beneficial for these bacteria to increase their intracellular magnetic dipole moment beyond the value needed to overcome Brownian motion in geomagnetic field conditions.
