NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, P.O. Box 59, 1790 AB Den Burg, Texel, the Netherlands.
Appl Environ Microbiol. 2010 Mar;76(5):1596-603. doi: 10.1128/AEM.01796-09. Epub 2010 Jan 4.
Anaerobic ammonium-oxidizing (anammox) bacteria have the unique ability to synthesize fatty acids containing linearly concatenated cyclobutane rings, termed "ladderane lipids." In this study we investigated the effect of temperature on the ladderane lipid composition and distribution in anammox enrichment cultures, marine particulate organic matter, and surface sediments. Under controlled laboratory conditions we observed an increase in the amount of C(20) [5]-ladderane fatty acids compared with the amount of C(18) [5]-ladderane fatty acids with increasing temperature and also an increase in the amount of C(18) [5]-ladderane fatty acids compared with the amount of C(20) [5]-ladderane fatty acids with decreasing temperature. Combining these data with results from the natural environment showed a significant (R(2) = 0.85, P = <0.0001, n = 121) positive sigmoidal relationship between the amounts of C(18) and C(20) [5]-ladderane fatty acids and the in situ temperature; i.e., there is an increase in the relative abundance of C(18) [5]-ladderane fatty acids at lower temperatures and vice versa, particularly at temperatures between 12 degrees C and 20 degrees C. Novel shorter (C(16)) and longer (C(22) to C(24)) ladderane fatty acids were also identified, but their relative amounts were small and did not change with temperature. The adaptation of ladderane fatty acid chain length to temperature changes is similar to the regulation of common fatty acid composition in other bacteria and may be the result of maintaining constant membrane fluidity under different temperature regimens (homeoviscous adaptation). Our results can potentially be used to discriminate between the origins of ladderane lipids in marine sediments, i.e., to determine if ladderanes are produced in situ in relatively cold surface sediments or if they are fossil remnants originating from the warmer upper water column.
厌氧氨氧化（anammox）细菌具有独特的合成含有线性串联环丁烷环的脂肪酸的能力，这些脂肪酸被称为“梯烷脂类”。在这项研究中，我们调查了温度对 anammox 富集培养物、海洋颗粒有机物质和表层沉积物中梯烷脂类组成和分布的影响。在受控的实验室条件下，我们观察到随着温度的升高，C(20)[5]-梯烷脂肪酸的含量相对于 C(18)[5]-梯烷脂肪酸的含量增加，而随着温度的降低，C(18)[5]-梯烷脂肪酸的含量相对于 C(20)[5]-梯烷脂肪酸的含量增加。将这些数据与自然环境的结果结合起来表明，C(18)和 C(20)[5]-梯烷脂肪酸的含量与原位温度之间存在显著的（R(2)=0.85，P<0.0001，n=121）正 S 型关系；即在较低的温度下，C(18)[5]-梯烷脂肪酸的相对丰度增加，反之亦然，特别是在 12 摄氏度到 20 摄氏度之间。还鉴定出了新型较短的（C(16))和较长的（C(22)到 C(24))梯烷脂肪酸，但它们的相对含量较小，且不受温度影响。梯烷脂类脂肪酸链长的适应温度变化类似于其他细菌中常见脂肪酸组成的调节，可能是在不同温度条件下维持膜流动性恒定的结果（同型适应）。我们的研究结果可用于区分海洋沉积物中梯烷脂类的来源，即确定梯烷脂类是否是在相对寒冷的表层沉积物中就地产生的，还是来自较温暖的上层水柱的化石残余物。
