Ecology, inhibitory activity, and morphogenesis of a marine antagonistic bacterium belonging to the Roseobacter clade
Ecology, inhibitory activity, and morphogenesis of a marine antagonistic bacterium belonging to the Roseobacter clade
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DOI：
10.1128/aem.71.11.7263-7270.2005
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发表时间：
2005-11-01
影响因子：
4.4
通讯作者：
Gram, L
中科院分区：
文献类型：
--
作者：
Bruhn, JB;Nielsen, KF;Gram, L
从大菱鲆仔鱼培育单位中分离到一株具有降低卵黄囊仔鱼死亡率的玫瑰红菌株27-4。在这里，我们证明了Roseen 27-4的上清液是致命的幼虫病原体鳗弧菌和灿烂弧菌在缓冲系统中，并抑制其在海洋肉汤中的生长。液相色谱法（LC）与紫外光谱检测和高分辨率质谱（HR-MS）确定了已知的抗菌化合物thiotropocin或其密切相关的前体tropodithietic酸的生物活性馏分。抗菌活性与褐色色素的外观相关，并且仅在静态生长条件下在海洋肉汤中形成。在静态生长条件下，多细胞星形聚集细胞在气液界面形成厚生物膜。在此，生物活性化合物是提取物的LC-UV色谱图中的基峰，其占总峰面积的15%。通气条件导致10倍更高的细胞产量，然而，文化是nonpigmented，不产生抗菌活性，并作为单细胞生长。抗菌化合物的产生可能是受群体调节的，我们使用LGHR-MS从Roseplant 27-4的培养物中鉴定出酰化高丝氨酸内酯（3-羟基癸酰基高丝氨酸内酯）。信号分子主要在停滞的培养物中检测到。玫瑰27-4在10 - 30摄氏度之间生长，但在37摄氏度时迅速死亡。此外，抗菌化合物对热敏感，在37 ℃下不到2天就灭活了，在25 ℃下8天就灭活了。使用Roseberry 27-4作为益生菌培养物将需要在停滞或粘附条件下建立，并且由于活性化合物的温度敏感性，必须确保恒定的生产。
Roseobacter strain 27-4 has been isolated from a turbot larval rearing unit and is capable of reducing mortality in turbot egg yolk sac larvae. Here, we demonstrate that the supernatant of Roseobacter 27-4 is lethal to the larval pathogens Vibrio anguillarum and Vibrio splendidus in a buffer system and inhibited their growth in marine broth. Liquid chromatography (LC) with both UV spectral detection and high-resolution mass spectrometry (HR-MS) identified the known antibacterial compound thiotropocin or its closely related precursor tropodithietic acid in the bioactive fractions. Antibacterial activity correlated with the appearance of a brownish pigment and was only formed in marine broth under static growth conditions. A thick biofilm of multicellular star-shaped aggregated cells formed at the air-liquid interface under static growth conditions. Here, the bioactive compound was the base peak in the LC-UV chromatograms of the extracts where it constituted 15% of the total peak area. Aerated conditions results in 10-fold-higher cell yield, however, cultures were nonpigmented, did not produce antibacterial activity, and grew as single cells. Production of antibacterial compounds may be quorum regulated, and we identified the acylated homoserine lactone (3-hydroxy-decanoyl homoserine lactone) from cultures of Roseobacter 27-4 using LGHR-MS. The signal molecule was primarily detected in stagnant cultures. Roseobacter 27-4 grew between 10 and 30 degrees C but died rapidly at 37 degrees C. Also, the antibacterial compounds was sensitive to heat and was inactivated at 37 degrees C in less than 2 days and at 25 degrees C in 8 days. Using Roseobacter 27-4 as a probiotic culture will require that is be established in stagnant or adhered conditions and, due to the temperature sensitivity of the active compound, constant production must be ensured.