Characteristics of magnetotactic bacteria in Duanjiapo loess section, Shaanxi Province and their environment significance  

作　　者：贾蓉芬 颜备战 李荣森 范国昌 林本海 

机构地区：[1]Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China [2]Department of Geostiences, Nanjing University, Nanjing 210008, China [3]Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China [4]Xi'an Laboratory of Loess and Quaternary Geology, Chinese Academy of Sciences, Xi'an 710061, China

出　　处：《Science China Earth Sciences》1996年第5期478-485,共8页中国科学（地球科学英文版）

基　　金：Project supported by the National Natural Science Foundation of China.

摘　　要：Magnetotactic bacteria (MB) have been isolated from 61 samples which have been collected from S0, L1, S1 and L2 layers in the Duanjiapo loess section. A few MB (<25 cell counts per sieve mesh) have been found in loess layers (L1, L2), bow-shaped, each cell containing only two magnetosomes. while much more MB (>125 cells counts per sieve mesh) have been found from paleosol layers (S0, S1), rod-shaped, each cell containing 8-26 magnetosomes arranged in irregular chains. Magnetosomes with Fe and Co as the main metallic elements are spheroid-shaped, and mainly round in cross-section. Normal saturated fatty acids in MB ranged from C14 to C28; almost no monounsaturated fatty acids have been identified. Most suitable oxygen content for MB growing is 10%, and low concentration of organic salt (0.02mmol/L qumsic iron) is beneficial to the forming of magnetosomes. Results suggest that the paleosol development stage is suitable for the growing of MB and the climate fluctuation periods for magnetosomes formation.Magnetotactic bacteria (MB) have been isolated from 61 samples which have been collected from S0, L1, S1 and L2 layers in the Duanjiapo loess section. A few MB (&lt;25 cell counts per sieve mesh) have been found in loess layers (L1, L2), bow-shaped, each cell containing only two magnetosomes. while much more MB (&gt;125 cells counts per sieve mesh) have been found from paleosol layers (S0, S1), rod-shaped, each cell containing 8-26 magnetosomes arranged in irregular chains. Magnetosomes with Fe and Co as the main metallic elements are spheroid-shaped, and mainly round in cross-section. Normal saturated fatty acids in MB ranged from C14 to C28; almost no monounsaturated fatty acids have been identified. Most suitable oxygen content for MB growing is 10%, and low concentration of organic salt (0.02mmol/L qumsic iron) is beneficial to the forming of magnetosomes. Results suggest that the paleosol development stage is suitable for the growing of MB and the climate fluctuation periods for magnetosomes formation.

关 键 词：LOESS SECTION magnetotactic bacteria (MB) MAGNETOSOME ENVIRONMENT significance. 

分 类 号：P318[天文地球—固体地球物理学]