Enhancing and Redirecting Cyanobacterial Electron Flow (Bioelectricity Spotlight)

细胞内电子的运动是生命的基础，并驱动细胞内发生的过程。对于光合作用的生物体来说，电子的运动可以由阳光提供动力，而对所有生物体来说，电子的运动可以由食物中化合物的新陈代谢提供动力。电子可以在细胞内用来合成有用的化合物。一些电子可以离开电池，产生电流，这些电流可以被收集并用作可再生能源。我们已经证明，这是可能的光合作用细菌(也被称为‘蓝藻’和‘蓝藻’)。它们可以利用太阳光产生外部电流。我们已经成功地利用这些细菌的电流驱动了一个微处理器--在新闻媒体上被强调为“藻类驱动的计算”。我们的长期目标之一是找到增加光合作用细菌产生的电流的方法，无论是细胞内还是细胞外。然而，我们对是什么决定了有多少电子可用，以及电子是如何到达细胞外部的知之甚少。这使得以定向、理性的方式改进这一过程变得困难。我们最近开发了一种方法来筛选大量的光合作用细菌细胞，以寻找具有基因变化(突变)的细胞，从而增加电子的可获得性。这一令人兴奋的进步使我们能够找到电子利用率更高的细胞，而不必事先假设这个过程是如何工作的。我们将获得改良的细胞，然后确定哪些突变是相关的。我们将测量改进后的细胞在细胞外产生电流的能力，以及在细胞内合成新化合物的能力。这对于生物技术开发这种“微生物电”将是重要的，也有助于我们回答有关是什么限制了电子运动的生物学问题。

The movement of electrons within cells is fundamental to life, and drives the processes that happen inside cells. For photosynthetic organisms, the movement of electrons can be powered by sunlight, and for all organisms it can be powered by the metabolism of compounds in food. The electrons can be used within cells in the synthesis of useful compounds. Some of the electrons can leave the cells, resulting in electric currents that can be harvested and used as a source of renewable energy. We have shown this is possible with photosynthetic bacteria (also known as 'blue-green algae' and 'cyanobacteria'). They can use sunlight to produce external electric current. We have succeeded in using the currents from these bacteria to drive a microprocessor - highlighted in the news media as 'algae-powered computing'. One of our long-term goals is to find ways to increase the electrical currents produced by photosynthetic bacteria, inside the cell or outside. However, we know little about what determines how many electrons are available, and how the electrons get to the outside of the cell. This makes it difficult to improve the process in a directed, rational way. We have recently developed a way of screening large numbers of photosynthetic bacterial cells for ones that have genetic changes (mutations) increasing electron availability. This exciting step forward allows us to find cells with improved electron availability without having to make assumptions in advance about how the process works. We will obtain improved cells, and then determine what the mutations responsible are. We will measure the ability of the improved cells to produce currents outside the cell, and to synthesis novel compounds inside the cell. This will be be important for biotechnological exploitation of this 'microbial electricity', and also help us to answer biological questions about what limits the movement of electrons.