Ribalet Francois, Intertaglia Laurent, Lebaron Philippe, Casotti Raffaella
Stazione Zoologica Anton Dohrn di Napoli, Villa Comunale, I80121 Napoli, Italy.
Aquat Toxicol. 2008 Jan 31;86(2):249-55. doi: 10.1016/j.aquatox.2007.11.005. Epub 2007 Nov 13.
Bioactive polyunsaturated aldehydes (PUAs) are produced by several marine phytoplankton (mainly diatoms) and have been shown to have a detrimental effect on a wide variety of organisms, including phytoplankton and invertebrates. However, their potential impact on marine bacteria has been largely neglected. We assess here the effect of three PUAs produced by marine diatoms: 2E,4E-decadienal, 2E,4E-octadienal and 2E,4E-heptadienal, on the growth of 33 marine bacterial strains, including 16 strains isolated during a bloom of the PUA-producing diatom Skeletonema marinoi in the Northern Adriatic Sea. A concentration-dependent growth reduction was observed for 19 bacterial strains at concentrations ranging from 3 to 145 micromolL(-1). Surprisingly, Eudora adriatica strain MOLA358 (Flavobacteriaceae) and Alteromonas hispanica strain MOLA151 (Alteromonadaceae) showed growth stimulation upon exposure to PUAs at concentrations between 13 and 18 micromolL(-1). The remaining 12 strains were unaffected by even very high PUA concentrations. Strains isolated during the diatom bloom showed remarkable resistance to PUA exposures, with only two out of 16 strains showing growth inhibition at PUA concentrations below 106, 130, and 145 micromolL(-1) for 2E,4E-decadienal, 2E,4E-octadienal and 2E,4E-heptadienal, respectively. No correlation between taxonomical position and sensitivity to PUA was observed. Considering that many bacteria thrive in close vicinity of diatom cells, it is likely that these compounds may shape the structure of associated bacterial communities by representing a selection force. This is even more relevant during the final stages of blooms, when senescence and nutrient limitation increase the potential production and release of aldehydes.
生物活性多不饱和醛（PUAs）由几种海洋浮游植物（主要是硅藻）产生，并已证明对包括浮游植物和无脊椎动物在内的多种生物具有有害影响。然而，它们对海洋细菌的潜在影响在很大程度上被忽视了。我们在此评估由海洋硅藻产生的三种PUAs：2E,4E-癸二烯醛、2E,4E-辛二烯醛和2E,4E-庚二烯醛对33种海洋细菌菌株生长的影响，其中包括在亚得里亚海北部产PUA的硅藻——海洋骨条藻水华期间分离出的16种菌株。在浓度范围为3至145微摩尔/升时，观察到19种细菌菌株的生长呈浓度依赖性降低。令人惊讶的是，亚得里亚海优多拉菌菌株MOLA358（黄杆菌科）和西班牙交替单胞菌菌株MOLA151（交替单胞菌科）在暴露于浓度为13至18微摩尔/升的PUAs时显示出生长刺激作用。其余12种菌株即使在非常高的PUA浓度下也不受影响。在硅藻水华期间分离出的菌株对PUA暴露表现出显著抗性，对于2E,4E-癸二烯醛、2E,4E-辛二烯醛和2E,4E-庚二烯醛，分别只有16种菌株中的两种在PUA浓度低于106、130和145微摩尔/升时显示出生长抑制。未观察到分类地位与对PUA的敏感性之间的相关性。鉴于许多细菌在硅藻细胞附近大量繁殖，这些化合物很可能通过作为一种选择力来塑造相关细菌群落的结构。在水华的最后阶段，当衰老和营养限制增加醛的潜在产生和释放时尤其如此。
