宋代海底沉船“南海Ⅰ号”出水木质文物中细菌类群

Bacterial communities in the waterlogged wooden cultural relics from the “Nanhai No. 1” shipwreck

摘要:

[目的]通过对"南海Ⅰ号"沉船出水木质文物标本中细菌类群的分析，了解饱水木质文物中的细菌类群并推测细菌对木质文物损害的机制。[方法]应用Illumina MiSeq测序平台对采自该沉船的10份木质文物标本中细菌V3-V4序列进行测序与分析，比较各标本中细菌群落的组成差异。[结果]根据97%序列相似性得到3 780不同的细菌OTUs，分属34目、35科的187个属；多数细菌OTU属于变形菌门（Proteobacteria）细菌，占全部细菌OTU的52.9%，在细菌纲水平上γ-变形菌纲（γ-Proteobacteria）（占17.9%）是丰度最高的细菌纲。德沃氏菌属（Devosia）（3.5%）是"南海一号"沉船样品丰度最高的属，其他分别属于甲基娇养杆菌属（Methylotenera）（2.4%）、鼠尾菌属（Muricauda）（1.2%）。其中氢噬胞菌属（Hydrogenophaga）、中国农大湖积物杆菌（Lacibacter cauensis）、德氏食酸菌（Acidovorax delafieldii）、德沃斯氏菌属（Devosia）、沉积物杆状菌属（Sediminibacterium）、缺陷短孢单胞菌（Brevundimonas diminuta）和门多萨假单胞菌（Pseudomonas mendocina）在所有样品中均可检测到。[结论]"南海Ⅰ号"沉船出水木质文物存在着种类丰富的好氧与厌氧细菌种类，多种细菌类群具有较好的纤维素降解能力与铁硫元素转化能力，控制细菌群落中参与分解纤维素的细菌与铁硫循环菌活性对于保护木质文物有重要作用。

Abstract:

[Objective] To understand the distribution of microorganisms and their effects on the waterlogged wooden relics collected from the "Nanhai No. 1" shipwreck. [Methods] Prokaryotic microorganisms in 10 wooden relics samples collected from the "Nanhai No. 1" shipwreck were identified by using high throughput sequencing technique. The composition and diversity of the bacterial communities in each sample were analyzed. [Results] Total 121 394 313 bacterial sequences with an average reading length of 458 bp were obtained. There were 3 780 different OTUs based on the similarity of the 97% sequences. According to the sequence in the GenBank database, 34 orders, 35 families and 187 genera of bacteria were involved in the wooded relics. Among these bacteria, most species were from Proteobacteria, and the species from Bacteroidetes ranked in the second. In the class level, the species from γ-Proteobacteria and α-Proteobacteria contributed more on community diversity. Hydrogenophaga, Lacibacter cauensis, Acidovorax delafieldii, Devosia, Sediminibacterium, Brevundimonas diminuta and Pseudomonas mendocina were found in all samples, and Muricauda, Thiobacillus, Rhodoplanes, Emticicia, Methylotenera mobilis and Flavobacterium were appeared with higher frequency of bacterial taxa. Principal component analysis showed that there were some differences in the composition of the bacterial community in different cultural relics. [Conclusion] There were rich biodiversity in prokaryotic microorganisms, both aerobic and anaerobic, in the archaeological wood from "Nanhai No. 1" shipwreck. The bacteria species, which participate in the decomposition of cellulose in the bacterial communities, resulted in a great challenge to the protection of cultural relics. At the same time, impact from iron-sulfur cycle bacteria should be taken into consideration due to they were existing in these relics.