Weis V M, Small A L, McFall-Ngai M J
Pacific Biomedical Research Center, University of Hawaii, Honolulu 96813, USA.
Proc Natl Acad Sci U S A. 1996 Nov 26;93(24):13683-8. doi: 10.1073/pnas.93.24.13683.
Many animal-bacteria cooperative associations occur in highly modified host organs that create a unique environment for housing and maintaining the symbionts. It has been assumed that these specialized organs develop through a program of symbiosis-specific or -enhanced gene expression in one or both partners, but a clear example of this process has been lacking. In this study, we provide evidence for the enhanced production of an enzyme in the symbiotic organ of the squid Euprymna scolopes, which harbors a culture of the luminous bacterium Vibrio fischeri. Our data show that this enzyme has a striking biochemical similarity to mammalian myeloperoxidase (MPO; EC 1.11.17), an antimicrobial dianisidine peroxidase that occurs in neutrophils. MPO and the squid peroxidase catalyze the same reaction, have similar apparent subunit molecular masses, and a polyclonal antibody to native human MPO specifically localized a peroxidase-like protein to the bacteria-containing regions of the symbiotic organ. We also provide evidence that a previously described squid cDNA encodes the protein (LO4) that is responsible for the observed dianisidine peroxidase activity. An antibody made against a fragment of LO4 immunoprecipiated dianisidine peroxidase activity from extracts of the symbiotic organ, and reacted against these extracts and human MPO in Western blot analysis. These data suggest that related biochemical mechanisms for the control of bacterial number and growth operate in associations that are as functionally diverse as pathogenesis and mutualism, and as phylogenetically distant as molluscs and mammals.
许多动物与细菌的合作关系发生在高度特化的宿主器官中，这些器官为共生菌的生存和维持创造了独特的环境。人们认为，这些特化器官是通过共生体一方或双方中特定于共生或增强共生的基因表达程序发育而来的，但这一过程一直缺乏明确的例子。在本研究中，我们提供证据表明，在乌贼Euprymna scolopes的共生器官中，一种酶的产生有所增强，该器官中栖息着发光细菌费氏弧菌。我们的数据表明，这种酶与哺乳动物髓过氧化物酶（MPO；EC 1.11.17）具有显著的生化相似性，MPO是一种存在于中性粒细胞中的抗微生物联茴香胺过氧化物酶。MPO和乌贼过氧化物酶催化相同的反应，具有相似的表观亚基分子量，并且针对天然人MPO的多克隆抗体将一种类似过氧化物酶的蛋白质特异性定位到共生器官中含有细菌的区域。我们还提供证据表明，先前描述的乌贼cDNA编码负责观察到的联茴香胺过氧化物酶活性的蛋白质（LO4）。针对LO4片段制备的抗体从共生器官提取物中免疫沉淀联茴香胺过氧化物酶活性，并在蛋白质印迹分析中与这些提取物和人MPO发生反应。这些数据表明，控制细菌数量和生长的相关生化机制在功能多样的关联中发挥作用，这些关联包括致病和互利共生，以及在系统发育上相距遥远的软体动物和哺乳动物。
