Genomic diversity and relatedness of bifidobacteria isolated from a porcine cecum
Genomic diversity and relatedness of bifidobacteria isolated from a porcine cecum
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DOI：
10.1128/jb.185.8.2571-2581.2003
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发表时间：
2003-04-01
影响因子：
3.2
通讯作者：
Ross, RP
中科院分区：
文献类型：
--
作者：
Simpson, PJ;Stanton, C;Ross, RP
这项研究最初涉及从猪盲肠的管腔或上皮中分离出一些双歧杆菌。在含有半胱氨酸盐酸盐(0.5g/L)和莫匹罗星(50 mg/L)的MRS平板上随机选择160株细菌。根据果糖-6-磷酸磷酸酮醇酶活性鉴定，所有菌株均为双歧杆菌。用限制性内切酶XbaI和脉冲场凝胶电泳法(PFGE)对基因组进行酶切后，这些分离物产生了15种不同的宏观限制性内切酶图谱。其中几种PFGE图谱仅有1、2或3个DNA片段的差异，并被归类为7种相关的PFGE类型，称为A至G。相关图谱似乎表明，由于染色体突变或可能的质粒水平转移，分离株内存在基因组可塑性。每种PFGE类型的相对频率在每个盲肠样本中保持不变，其中PFGE类型E约占分离株的50%。用随机扩增的多态DNA聚合酶链式反应、细胞形态、全细胞蛋白图谱、16S核糖体DNA测序和DNA-DNA杂交来确定这7个明显无关的PFGE类型是否代表了遗传上的不同分离株。共鉴定出4个类群：A、C/D/G、B/E和F型，它们似乎代表了双歧杆菌最小亚种--伪长双歧杆菌亚种。和伪龙双歧杆菌亚种。Globosum和两个新种。这些数据表明，在一个相对简单的双歧杆菌种群中存在相当大的基因组多样性，该种群由15个不同的菌株组成，分别代表四个组，这种多样性在猪盲肠内容物和上皮层始终保持。
This study initially involved the isolation of a number of bifidobacteria from either the lumen or the epithelium of a porcine cecum. A total of 160 isolates were selected at random on MRS plates containing cysteine hydrochloride (0.5 g/liter) and mupirocin (50 mg/liter). All were identified as bifidobacteria based on fructose-6-phosphate phosphoketolase activity. Following genomic digestion with the restriction enzyme XbaI and pulsed-field gel ellectrophoresis (PFGE), the isolates produced 15 distinct macro-restriction patterns. Several of the PFGE patterns differed by only 1, 2, or 3 DNA fragments and were grouped as related patterns into seven, PFGE types, termed A through G. The related patterns appeared to show genomic plasticity within the isolates arising from chromosomal mutations or possibly horizontal transfer of plasmids. The relative frequency of each PFGE type was maintained within each cecal sample, with PFGE type E representing approximately 50% of the isolates. Randomly amplified pollymorphic DNA PCR, cell morphology, whole-cell protein profiling, 16S ribosomal DNA sequencing, and DNA-DNA hybridization were used to determine if the seven apparently unrelated PFGE types represented genetically distinct isolates. Four groups were identified: PFGE types A, C/D/G, B/E, and F, and these appeared to represent Bifidobacterium minimum, Bifidobacterium pseudolongum subsp. pseudolongum, and Bifidobacterium pseudolongum subsp. globosum and two new species, respectively. The data demonstrate the presence of considerable genomic diversity within a relatively simple bifidobacteria population, consisting of 15 distinct strains representing four groups, which was maintained throughout the porcine cecal contents and epithelial layer.