PDF(Pubmed)
Abstract：
The spoilage of vacuum-packed meat by Clostridium estertheticum complex (CEC), which is accompanied by or without production of copious amounts of gas, has been linked to the acetone-butyrate-ethanol fermentation, but the mechanism behind the variable gas production has not been fully elucidated. The reconstruction and comparison of intra- and interspecies metabolic pathways linked to meat spoilage at the genomic level can unravel the genetic basis for the variable phenotype. However, this is hindered by unavailability of CEC genomes, which in addition, has hampered the determination of genetic diversity and its drivers within CEC. Therefore, the current study aimed at determining the diversity of CEC through comprehensive comparative genomics. Fifty CEC genomes from 11 CEC species were compared. Recombination and gene gain/loss events were identified as important sources of natural variation within CEC, with the latter being pronounced in genomospecies2 that has lost genes related to flagellar assembly and signaling. Pan-genome analysis revealed variations in carbohydrate metabolic and hydrogenases genes within the complex. Variable inter- and intraspecies gas production in meat by C. estertheticum and Clostridium tagluense were associated with the distribution of the [NiFe]-hydrogenase hyp gene cluster whose absence or presence was associated with occurrence or lack of pack distention, respectively. Through comparative genomics, we have shown CEC species exhibit high genetic diversity that can be partly attributed to recombination and gene gain/loss events. We have also shown genetic basis for variable gas production in meat can be attributed to the presence/absence of the hyp gene cluster.
摘要：
梭状芽胞杆菌（CEC）对真空包装肉的腐败，伴随着或不产生大量的气体，与丙酮-丁酸-乙醇发酵有关,但是可变天然气产量背后的机制尚未完全阐明。在基因组水平上重建和比较与肉类腐败相关的种内和种间代谢途径可以揭示可变表型的遗传基础。然而,这受到CEC基因组不可用的阻碍，此外，阻碍了CEC内部遗传多样性及其驱动因素的确定。因此,本研究旨在通过综合比较基因组学确定CEC的多样性。比较了来自11个CEC物种的50个CEC基因组。重组和基因增益/丢失事件被确定为CEC内自然变异的重要来源，后者在基因组中明显2丢失了与鞭毛组装和信号传导相关的基因。全基因组分析揭示了复合物中碳水化合物代谢和氢化酶基因的变化。由C.estetheticum和梭状芽胞杆菌在肉中产生的不同种间和种内气体与[NiFe]-氢化酶hyp基因簇的分布有关，该基因簇的存在或存在与发生或缺乏包装扩张有关，分别。通过比较基因组学，我们已经表明CEC物种表现出很高的遗传多样性，这可以部分归因于重组和基因获得/丢失事件。我们还表明，肉类中可变气体产生的遗传基础可归因于hyp基因簇的存在/不存在。
