食品科学 ›› 2021, Vol. 42 ›› Issue (18): 37-44.doi: 10.7506/spkx1002-6630-20200805-078

• 生物工程 • 上一篇    下一篇

氨基酸对植物乳杆菌KLDS1.0391生长及细菌素合成的影响

赵乐,张晓桐,刘利军,谢水琪,靳奇文,孟祥晨   

  1. (东北农业大学 乳品科学教育部重点实验室,黑龙江 哈尔滨 150030)
  • 发布日期:2021-09-29
  • 基金资助:
    国家自然科学基金面上项目(31671917)

Effects of Amino Acids on Growth and Bacteriocin Synthesis of Lactobacillus plantarum KLDS1.0391

ZHAO Le, ZHANG Xiaotong, LIU Lijun, XIE Shuiqi, JIN Qiwen, MENG Xiangchen   

  1. (Key Laboratory of Dairy Science, Ministry of Education, Northeast Agricultural University, Harbin 150030, China)
  • Published:2021-09-29

摘要: 为探究氨基酸对植物乳杆菌生长及细菌素合成的影响,调节化学成分确定培养基中的氨基酸组成,培养植物乳杆菌KLDS1.0391,采用高效液相色谱法测定乳酸含量,通过实时聚合酶链式反应(real-time polymerase chain reaction,real-time PCR)分析细菌素和氨基酸合成相关基因的表达。结果表明,天冬氨酸、组氨酸、异亮氨酸、亮氨酸、脯氨酸、苏氨酸、酪氨酸、天冬酰胺及谷氨酰胺的缺失导致该菌生长能力和细菌素合成量均显著降低(P<0.05);谷氨酸、甘氨酸、丙氨酸、半胱氨酸、精氨酸、苯丙氨酸、丝氨酸、色氨酸及缬氨酸的缺失仅影响菌体生长,对细菌素合成无明显影响;而赖氨酸胁迫(缺失及过量)对菌体的生长影响很小,但却显著影响细菌素的合成。色谱结果显示,赖氨酸、酪氨酸、异亮氨酸、亮氨酸、甲硫氨酸、天冬氨酸、天冬酰胺、脯氨酸及苏氨酸单缺失后乳酸含量升高。real-time PCR结果表明,细菌素合成相关基因plnEF、plnD及plNC8HK因赖氨酸的缺失表达显著下调(P<0.05),而上述基因在外源赖氨酸质量浓度达到2.0 g/L前,上调水平随赖氨酸添加量的增大而增大。氨基酸合成关键基因dapG、yclM 因赖氨酸缺失表达显著上调,相反,上述基因在赖氨酸质量浓度为2.0 g/L时表达量显著下调(P<0.05)。由上述研究结果推测,当赖氨酸缺失时,菌体通过上调基因dapG 和yclM 的表达以合成多种蛋白质保证其正常生长代谢,赖氨酸可正向诱导该菌细菌素合成,其可能作为细菌素合成底物发挥作用。

关键词: 植物乳杆菌;细菌素;氨基酸;基因表达;实时聚合酶链式反应

Abstract: The main purpose of this study is to explore the effects of amino acids on the growth and bacteriocin synthesis of Lactobacillus plantarum. L. plantarum KLDS1.0391 was cultured in chemically?defined?medium with predetermined concentrations of amino acids. The content of lactic acid in the culture supernatant was determined by high performance liquid chromatography (HPLC). The expression of the genes associated with bacteriocin and amino acid synthesis was analyzed by real-time polymerase chain reaction (real-time PCR). The results showed that the deficiency of Asp, His, Ile, Leu, Pro, Thr, Tyr, Asn, and Gln significantly reduced the growth capacity and bacteriocin production of the strain (P < 0.05). The deficiency of Glu, Gly, Ala, Cys, Arg, Phe, Ser, Trp and Val affected only the growth of the bacterium, but had no obvious effect on the synthesis of bacteriocin. Lys stress (deficiency or excess) had little effect on the growth of the strain, but significantly affected the synthesis of bacteriocin by it. The chromatographic results showed that single deficiency of Lys, Tyr, Ile, Leu, Met, Asp, Asn, Pro or Thr increased the lactic acid content. Real-time-PCR showed that the genes related to bacteriocin synthesis plnEF, plnD and plNC8HK were significantly down-regulated in the absence of Lys (P < 0.05), while they were up-regulated more significantly with increasing exogenous Lys up to 2.0 g/L. The key genes involved in amino acid synthesis dapG and yclM were significantly up-regulated in the absence of Lys, but down-regulated in the presence of 2.0 g/L Lys (P < 0.05). Therefore, it can be speculated that in the absence of Lys, the expression of genes such as dapG and yclM is up-regulated to synthesize a variety of proteins essential to the growth and metabolism of bacteria. Lysine can positively induce bacteriocin synthesis, which may play an important role as a substrate for bacteriocin synthesis.

Key words: Lactobacillus plantarum; bacteriocin; amino acid; gene expression; real-time polymerase chain reaction

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