青岛潮间带沉积物可培养厌氧细菌多样性的研究

Diversity of culturable anaerobic bacteria isolated from intertidal sediments of Qingdao

为了验证设计的简易厌氧培养方法，作者以青岛潮间带沉积物为研究对象，采用5种培养基，从青岛潮间带沉积物共分离获得138株厌氧细菌。16S rDNA 序列分析表明，这些细菌分属3个门15个属32个种，其中γ-变形菌纲64株18个种，在种类上处于优势地位；此外还包括δ-变形菌纲（δ-Proteobacteria）16株2个种，ε-变形菌纲4株1个种，拟杆菌门（Bacteroidetes）29株8个种，梭杆菌门（Fusobacteria）25株3个种。在属水平上，弧菌属（Vibrio）、Marinifilum属、泥杆菌属（Ilyobacter）、脱硫弧菌属（Desulfovibrio）、希瓦氏菌属（Shewanella）在数量上占优势。此外，有26株8种细菌（占总菌株数的18.84%）与已知菌的同源性介于89.38%～94.22%，为潜在的海洋细菌新科或新属，表明此简易厌氧菌培养方法在获得新菌方面具有较大优势。另外，研究结果还表明，不同培养基对特定的类群具有选择性：2216E 培养基对γ-变形菌纲分离培养效率较高； SPG 培养基在获得新菌方面具有优势（占新菌数62.5%），且这些新菌大多属于拟杆菌门和梭杆菌门，其中 SPG-1培养基对于分离硫酸盐还原菌和难培养的ε-变形菌纲细菌具有优势， SPG-4培养基对分离硝酸盐还原菌具有优势。

Oxygen is consumed within the first few millimeters or centimeters of the intertidal sediments, which makes the lower layer as an anaerobic ambient with abundant anaerobic bacteria. However, little information is avallable about culturable anaerobic bacteria inhabiting intertidal sediments. In order to prove the simple method for anaerobic bacteria isolation, intertidal sediments of Qingdao were chosen as the objects for study. Five different anaerobic media were used for the isolation, and then isolates were identified using 16S rRNA gene sequences. A total of 138 bacterial isolates clus-tered into 3 phyla, 15 genera and 32 species were recorded. Bacterial isolates belonged toγ-Proteobacteria were recorded as a highly dominant （64 isolates and 18 species）, followed by δ-Proteobacteria （16 isolates and 2 species）,ε-Proteobacteria （4 isolates and 1 species）, Bacteroidetes （29 isolates and 8 species） and Fusobacteria （25 isolates and 3 species）. Furthermore, at the genus level investigation, Vibrio was recorded as the most common genara among all the isolates, followed by Marinifilum, Ilyobacter, Desulfovibrio and Shewanella, etc. Notably, there were 26 isolates and 8 species （18.84%） which might belong to novel families or genus, whose homology was recorded between 89.38%and 94.22%, with one belonged to rarely isolatedε-Proteobacteria. All the results above indicated that the fast, simple and easily designed method had some advantages in isolating novel stralns. Moreover, the study investigated that the different media and enrichment strategies were selective for specific bacterial groups. The medium 2216E showed a better effect in the diversity of bacterial isolates, and the medium SPG showed a better effect in the separation of novel bacteria, espe-cially for Bacteroidetes and Fusobacteria. Meanwhile, the SPG-1 Medium showed a greater capability to isolate SRB and bacteria ofε-Proteobacteria, and SPG-4 medium prone to isolating NRB.