A bacterial sulfonolipid triggers multicellular development in the closest living relatives of animals.
A bacterial sulfonolipid triggers multicellular development in the closest living relatives of animals.
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作者：
Alegado RA;Brown LW;Cao S;Dermenjian RK;Zuzow R;Fairclough SR;Clardy J;King N
细菌产生的小分子通过我们知之甚少的机制对动物健康、形态发生和进化产生深远的影响。在动物的现存近亲之一——领鞭毛虫 Salpingoeca Rosetta 中，我们发现莲座菌落的发育是由猎物细菌 Algoriphagus machipongonensis 及其拟杆菌门中的近亲诱导的。在这里，我们发现由 A. machipongonensis 产生的玫瑰花结诱导因子 (RIF-1) 属于一小类磺脂类，它是众所周知的鞘脂类的默默无闻的亲戚，在植物、动物和真菌的信号传递中发挥着重要作用。 RIF-1 具有非凡的效力（飞摩尔，或 10−15 M），S. Rosetta 可以在宽广的动态范围（九个数量级）上对其做出反应。这项研究提供了细菌磺脂触发真核形态发生的典型例子，并提出了细菌可能促进动物进化的分子机制。 DOI：http://dx.doi.org/10.7554/eLife.00013.001 所有动物，包括人类，都是在一个充满细菌的世界中进化的。尽管细菌是最常见的病原体，但一些细菌会产生对动物和其他真核生物的生物学至关重要的小分子，尽管这些细菌分子的有益方式的细节尚不清楚。领鞭毛虫是水生生物，它们利用鞭状鞭毛四处移动，以细菌为食。它们可以作为一个细胞或多个细胞的群体存在，也许令人惊讶的是，它们是已知的与动物最接近的近亲。这意味着对这些生物体的实验有可能提高我们对动物发育以及从卵到胚胎再到成体的转变的理解。阿莱加多等人。研究人员探索了 Salpingoeca Rosetta（一种形成菌落的领鞭毛虫）的形态如何受到其与各种细菌的相互作用的影响。特别是，他们发现 S. Rosetta 的多细胞性发育是由 Algoriphagus machipongonensis 及其近亲细菌的存在引发的。他们还鉴定出细菌产生的信号分子是C32H64NO7S；这种脂质分子是鞘脂分子的一个不起眼的亲戚，鞘脂分子在动物、植物和真菌的信号传递中发挥着重要作用。此外，阿莱加多等人。表明 S. Rosetta 可以在很宽的浓度范围内（包括低至 10−17 M 的浓度）对这种分子（他们称之为玫瑰花诱导因子 (RIF-1)）做出反应。Alegado 等人的工作。表明罗塞塔链球菌和噬菌体细菌之间的相互作用可能是一个富有成效的模型系统，用于研究细菌对动物细胞生物学的影响，以及研究信号传递和接收的机制。此外，这项工作揭示的分子机制开启了细菌可能促进动物多细胞进化的可能性。 DOI：http://dx.doi.org/10.7554/eLife.00013.002
Bacterially-produced small molecules exert profound influences on animal health, morphogenesis, and evolution through poorly understood mechanisms. In one of the closest living relatives of animals, the choanoflagellate Salpingoeca rosetta, we find that rosette colony development is induced by the prey bacterium Algoriphagus machipongonensis and its close relatives in the Bacteroidetes phylum. Here we show that a rosette inducing factor (RIF-1) produced by A. machipongonensis belongs to the small class of sulfonolipids, obscure relatives of the better known sphingolipids that play important roles in signal transmission in plants, animals, and fungi. RIF-1 has extraordinary potency (femtomolar, or 10−15 M) and S. rosetta can respond to it over a broad dynamic range—nine orders of magnitude. This study provides a prototypical example of bacterial sulfonolipids triggering eukaryotic morphogenesis and suggests molecular mechanisms through which bacteria may have contributed to the evolution of animals. DOI: http://dx.doi.org/10.7554/eLife.00013.001 All animals, including humans, evolved in a world filled with bacteria. Although bacteria are most familiar as pathogens, some bacteria produce small molecules that are essential for the biology of animals and other eukaryotes, although the details of the ways in which these bacterial molecules are beneficial are not well understood. The choanoflagellates are water-dwelling organisms that use their whip-like flagella to move around, feeding on bacteria. They can exist as one cell or a colony of multiple cells and, perhaps surprisingly, are the closest known living relatives of animals. This means that experiments on these organisms have the potential to improve our understanding of animal development and the transition from egg to embryo to adult. Alegado et al. have explored how the morphology of Salpingoeca rosetta, a colony-forming choanoflagellate, is influenced by its interactions with various species of bacteria. In particular, they find that the development of multicellularity in S. rosetta is triggered by the presence of the bacterium Algoriphagus machipongonensis as well as its close relatives. They also identify the signaling molecule produced by the bacteria to be C32H64NO7S; this lipid molecule is an obscure relative of the sphingolipid molecules that have important roles in signal transmission in animals, plants, and fungi. Moreover, Alegado et al. show that S. rosetta can respond to this molecule – which they call rosette-inducing factor (RIF-1) – over a wide range of concentrations, including concentrations as low as 10−17 M. The work of Alegado et al. suggests that interactions between S. rosetta and Algoriphagus bacteria could be a productive model system for studying the influences of bacteria on animal cell biology, and for investigating the mechanisms of signal delivery and reception. Moreover, the molecular mechanisms revealed by this work leave open the possibility that bacteria might have contributed to the evolution of multicellularity in animals. DOI: http://dx.doi.org/10.7554/eLife.00013.002