Xu Xinglian

Improved screening procedure for biogenic amine production by lactic acid bacteria and Enterobacteria.

Shiling L., Caihong J., Xinglian X., Chengjian X., Kaixiong L., Ruihua S. (2015): Improved screening procedure for biogenic amine production by lactic acid bacteria and Enterobacteria. Czech J. Food Sci., 33: 19–26. An improved screening procedure was developed for the detection of amino acid decarboxylase-positive microorganisms (especially lactic acid bacteria and Enterobacteria). Monolayer culture and double layer colour development methods for the detection of amino acid decarboxylase-positive lactic acid bacteria and Enterobacteria were established. Bio genic amine-positive bacteria strain was isolated directly from the samples. The applicability and detection level of the designed medium were quantitatively evaluated by the confirmation of the amine-forming capacity using an HPLC procedure, while tyrosine decarboxylase and lysine decarboxylase genes were detected by PCR with specific primers. The screening method showed a good correlation with the chemical analysis and molecular detection. Enterobacter

酰基-高丝氨酸内酯(AHL)对鼠伤寒沙门氏菌生物菌膜形成的影响

目的研究铜绿假单胞菌所产生的群体感应信号分子酰基-高丝氨酸内酯（AHL）对鼠伤寒沙门氏菌生物菌膜形成的影响，为不同菌体间群体感应的研究提供参考，为沙门氏菌的控制提供帮助。 方法利用薄层层析法分析铜绿假单胞菌所产生AHL的成分，并通过添加0%、1.0%、1.5%、2.0%（体积分数）的AHL来研究其对鼠伤寒沙门氏菌生物菌膜形成、浮游菌体生长以及菌体泳动能力的影响。 结果铜绿假单胞菌产生2种相同类型的AHL分子（C12-HSL和3-oxo-C8-HSL），100 ℃加热5 min并不会改变AHL的成分。当AHL添加量低于1.5%时，虽然浮游菌体指数生长时期受到一定抑制，但随着时间的延长，稳定期浮游菌体的生长并无显著差异，反观生物菌膜，其形成明显受到抑制。当AHL添加量达到2%时，浮游菌体生长和生物菌膜形成均受到显著抑制，说明AHL对鼠伤寒沙门氏菌生物菌膜的形成有明显抑制作用。AHL对单一菌体泳动性有显著抑制作用，而对群体泳动性有不同程度的促进作用。 结论群体感应信号分子AHL对鼠伤寒沙门氏菌浮游菌体生长的影响受添加量调控，当AHL添加量增加到一定值时浮游菌体生长才受到抑制，但对生物菌膜的形成有明显抑制作用，且随着AHL添加量提高，抑制作用增强。