The measurement of microbial carbohydrate exopolymers from intertidal sediments
The measurement of microbial carbohydrate exopolymers from intertidal sediments
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DOI：
10.4319/lo.1995.40.7.1243
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发表时间：
1995-11-01
影响因子：
4.5
通讯作者：
Parkes, RJ
中科院分区：
文献类型：
--
作者：
Underwood, GJC;Paterson, DM;Parkes, RJ
测量自然界中微生物胞外聚合物（EPS）是了解潮间带沉积物生物稳定化过程和微生物生态学的必要条件。沉积物中的EPS可以通过苯酚-硫酸测定法来测量沉积物样品中的碳水化合物浓度。对河口潮间带沉积物中碳水化合物组分的储存和提取方法进行了比较研究。总碳水化合物浓度和胶体碳水化合物浓度（水提取和离心后保留在悬浮液中的材料）的测量高度依赖于储存条件、样本量、提取介质和时间。沉淀（在70%的乙醇）的EPS从盐水（千分之25）提取胶体碳水化合物（胶体S）从四个不同的沉积物微生物组合表明，20%的胶体碳水化合物存在于提取物中的EPS组成。胶体S浓度与硅藻生物量高度相关，由叶绿素a浓度确定。使用100 mM Na（2）EDTA作为提取介质（胶体EDTA）的提取增加了获得的胶体碳水化合物的浓度，并且在以细菌和蓝藻为主的沉积物中，将材料中EPS的百分比增加到38%。糖醛酸占总沉淀物和胶体-S提取物中测得的碳水化合物总量的20%，但在胶体-EDTA提取物中增加到65%，表明胶体-EDTA提取物去除细菌荚膜EPS和与沉淀物颗粒更密切相关的EPS。
Measurements of microbial extracellular polymeric substances (EPS) of natural field populations are required to understand the processes of biogenic stabilization and the microbial ecology of intertidal sediments. EPS in sediments can be measured by the phenol-sulfuric acid assay to measure carbohydrate concentration in sediment samples. We conducted comparative studies of storage and extraction methods for carbohydrate fractions on intertidal estuarine sediments. Measurements of both total and colloidal (material remaining in suspension after aqueous extraction and centrifugation) carbohydrate concentrations were highly dependent on storage conditions, sample size, extraction media, and time. Precipitation (in 70% ethanol) of EPS from saline (25 parts per thousand) extractions of colloidal carbohydrate (colloidal S) from four different sediment microbial assemblages showed that 20% of colloidal carbohydrate present in extracts consisted of EPS. Concentrations of colloidal S were highly correlated with diatom biomass as determined by chlorophyll a concentrations. Extractions that used 100 mM Na(2)EDTA as the extracting medium (colloidal EDTA) increased the concentrations of colloidal carbohydrate obtained and, in sediments dominated by bacteria and cyanobacteria, increased the percentage of EPS in the material to 38%. Uronic acids comprised 20% of the total amount of carbohydrate measured in both total sediment and colloidal-S extracts but increased to 65% in colloidal-EDTA extracts, suggesting that colloidal-EDTA extractions remove bacterial capsular EPS and EPS more closely associated with sediment particles.