Vertical Distribution of Methanogens in the Anoxic Sediment of Rotsee (Switzerland)
Vertical Distribution of Methanogens in the Anoxic Sediment of Rotsee (Switzerland)
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DOI：
10.1128/aem.65.6.2402-2408.1999
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发表时间：
1999-06
影响因子：
4.4
通讯作者：
K. Zepp Falz;C. Holliger;R. Großkopf;W. Liesack;A. N. Nozhevnikova;B. Müller;B. Wehrli;D. Hahn
中科院分区：
文献类型：
--
作者：
K. Zepp Falz;C. Holliger;R. Großkopf;W. Liesack;A. N. Nozhevnikova;B. Müller;B. Wehrli;D. Hahn
摘要利用分子生物学技术和放射性示踪技术，对瑞士Rotsee的Anodermis沉积物中甲烷菌的存在和多样性进行了分析。经过PCR辅助序列检索的16 S rRNA基因（16 S rDNA）从缺氧沉积物的Rotsee，克隆和测序，系统发育分析确定了两个集群的序列和4个分离的克隆。聚类1中的序列与Methanosaeta spp.而簇2中的序列包含瘤斜蚤的产甲烷内共生体。针对这两个簇和两个分离的克隆构建区分性寡核苷酸探针。这些探针随后被用于分析土著产甲烷菌在沉积物的核心，除了针对域的成员细菌和细菌和荧光染料4′，6-diamidino-2-phenylindole（DAPI）的域特异性探针，通过荧光原位杂交。DAPI染色后，沉积物上层的微生物密度最高，随深度增加，密度从（1.01 ± 0.25）× 1010个/g沉积物下降到（2.62 ± 0.58）× 1010个/g沉积物（干重）。该区域对应于最高代谢活性的区域，如氨、碱度和pH曲线所示，而甲烷曲线恒定。探针Eub 338和Arch 915分别检测到平均16%和6%的DAPI染色的细胞作为细菌和细菌的成员。探针Rotcl 1鉴定出平均4%的DAPI染色细胞为甲烷菌属，它们遍布整个地核相比之下，探针Rotcl 2确定只有0.7%的DAPI染色的细胞作为亲属的产甲烷内共生体的P. nasuta，这是目前唯一的上2厘米的沉积物。探针Rotp 13和Rotp 17未检测到任何细胞。这两个产甲烷种群的空间分布对应于通过与[14 C]乙酸盐或[14 C]碳酸氢盐孵育确定的甲烷产生速率。乙酸盐的产甲烷作用几乎占总甲烷产量的全部，这与乙酸裂解甲烷菌属的优势一致。平均占古细菌总数的91%显着的氢营养产甲烷被发现，只有在有机富集的上2厘米的沉积物，其中可能的氢营养亲属的产甲烷内共生体的P. nasuta，占古菌种群的7%，也被检测到。
ABSTRACT Anoxic sediments from Rotsee (Switzerland) were analyzed for the presence and diversity of methanogens by using molecular tools and for methanogenic activity by using radiotracer techniques, in addition to the measurement of chemical profiles. After PCR-assisted sequence retrieval of the 16S rRNA genes (16S rDNA) from the anoxic sediment of Rotsee, cloning, and sequencing, a phylogenetic analysis identified two clusters of sequences and four separated clones. The sequences in cluster 1 grouped with those of Methanosaeta spp., whereas the sequences in cluster 2 comprised the methanogenic endosymbiont ofPlagiopyla nasuta. Discriminative oligonucleotide probes were constructed against both clusters and two of the separated clones. These probes were used subsequently for the analysis of indigenous methanogens in a core of the sediment, in addition to domain-specific probes against members of the domains Bacteria andArchaea and the fluorescent stain 4′,6-diamidino-2-phenylindole (DAPI), by fluorescent in situ hybridization. After DAPI staining, the highest microbial density was obtained in the upper sediment layer; this density decreased with depth from (1.01 ± 0.25) × 1010 to (2.62 ± 0.58) × 1010 cells per g of sediment (dry weight). This zone corresponded to that of highest metabolic activity, as indicated by the ammonia, alkalinity, and pH profiles, whereas the methane profile was constant. Probes Eub338 and Arch915 detected on average 16 and 6% of the DAPI-stained cells as members of the domains Bacteriaand Archaea, respectively. Probe Rotcl1 identified on average 4% of the DAPI-stained cells as Methanosaeta spp., which were present throughout the whole core. In contrast, probe Rotcl2 identified only 0.7% of the DAPI-stained cells as relatives of the methanogenic endosymbiont of P. nasuta, which was present exclusively in the upper 2 cm of the sediment. Probes Rotp13 and Rotp17 did not detect any cells. The spatial distribution of the two methanogenic populations corresponded well to the methane production rates determined by incubation with either [14C]acetate or [14C]bicarbonate. Methanogenesis from acetate accounted for almost all of the total methane production, which concurs with the predominance of acetoclastic Methanosaeta spp. that represented on average 91% of the archaeal population. Significant hydrogenotrophic methanogenesis was found only in the organically enriched upper 2 cm of the sediment, where the probably hydrogenotrophic relatives of the methanogenic endosymbiont of P. nasuta, accounting on average for 7% of the archaeal population, were also detected.