FISH方法解析大辽河入海口沉积物中微生物的垂直分布特征

Characterization of microbial vertical distribution in sediment from the estuary of the Daliao River by the FISH method

取大辽河入海口柱状沉积物,通过寡核苷酸荧光探针原位杂交(FISH)方法分析了沉积物中微生物数量及种群的垂直分布特征,并考察了沉积物理化特性对微生物丰度的影响.结果表明,用5-(4,6-二氯三嗪基)氨基荧光素(简称DTAF)染料染色及EUB338探针杂交检测出的微生物细胞总数及细菌数量随沉积物深度呈现相同变化趋势.在沉积物表层(0～5cm)和中间层(23.5～29.5cm)数量相对较高.细胞总数为7.9×108～20.1×108cel.lcm-3,细菌数量为5.1×108～14.4×108个.cm-3,细菌检出率平均值为75.4%.用ALF1b、BET42a和GAM42a探针检测出α-、β-和γ-变形杆菌在柱状沉积物中的普遍存在,α-、β-和γ-变形杆菌检出量占细胞总数的25.0%～65.6%,其中以γ-变形杆菌为优势菌,其检出率为9.8%～40.8%.用ARCH915探针检测出的古细菌数量占细胞总量的1.0%～11.8%.总体看来,沉积物中微生物数量与沉积物的粘土含量呈正相关,在一定程度上受总有机碳影响,但与汞含量关系不明显.

Vertical distribution of microbial population and community along a sediment core profile from the estuary of the Daliao River was analyzed by Fluorescence in Situ Hybridization （FISH）. In addition, effects of sediment physiochemical properties on microbial richness were investigated. The results showed the total cell number detected by staining with 5-（4, 6-dichlorotriazinyl） aminofluorescein （DTAF） and the number of domain Bacteria determined by hybridization with the EUB338 oligonucleotide probe followed similar trends along the sediment profile. Relatively higher cell numbers were found in the upper （0 ～ 5 cm） and middle （23.5 ～29.5 cm） parts of the sediment core profile. The total cell number ranged over 7.9 ×10^8～ 20.1 ×10^8cell·cm^-3, and the bacteria number ranged 5.1×10^8 ～ 14.4 ×10^8 cell·cm^-3. The average bacteria detection frequency was 75.4%. Hybridization with ALF1b, BET42a and GAM42a probes showed that α-、β-and γ-proteobacteria were popular species in the sediment core, accounting for 25.0% ～ 65.6% of the total cells, and γ-proteobacteria predominating at 9.8% -40.8%. Archaea detected by probe ARCH915 accounted for 1.0% - 11.8% of the total cell number. The bacteria number in the sediment was positively correlated to sediment clay content, influenced by TOC content to some extent, but not correlated to mercury content.