Exploring the anaerobic adaptations of the mitochondrion-related organelles of Blastocystis

芽囊原虫是一种寄生虫，通常在从患有胃病的人和其他动物身上提取的样本中发现。它是一种微小的有机体，只能在完全没有氧气的环境中生存。仅这一点就突显了芽囊原虫的不同寻常，因为与它有密切遗传关系的生物体都不会受到充氧环境的负面影响。一些研究报告显示了芽囊原虫的特殊性，在这些研究报告中观察到了芽囊原虫内不寻常的结构，这些结构被报告为“线粒体相关细胞器”(MROs)。MRO在形状上相似，但已被预测为与典型线粒体的蛋白质组成不同。在寄生生物中有几种类型的不规则线粒体，最常见的是氢小体(产生分子氢)和有丝分裂体(功能未知)。芽囊原虫中的MRO既不完全符合这两种类型，也显示了两者的特征，以及正常的线粒体。拟议中的研究将努力揭开围绕这种奇怪的有机体及其同样奇怪的内部结构的谜团。利用现代生物化学和蛋白质组学技术，我们将寻求鉴定芽囊原虫中的蛋白质，这些蛋白质可以作用于其特有的线粒体。这项研究的框架是基于以前的实验，尽管这些实验成功地预测了许多蛋白质和代谢途径，但主要产生了假设和非决定性的结果。通过扩大实验规模，在不同的大气条件下培养芽囊原虫，以及使用替代互补系统，我们将确定这些假想蛋白质的功能。此外，将调查的环境条件包括观察蛋白质浓度的变化以及与有机体环境含氧量变化有关的功能。作为一种寄生虫，这种生物在宿主之间转移时经常暴露在氧气中，所以我们将研究芽囊原虫如何在这种转变中生存。同样，我们将研究环境中铁浓度的影响，以调查芽囊原虫如何回收所需的铁，以形成对其许多蛋白质的功能至关重要的不同复合体。使芽囊原虫变得更加神秘的是，它还表明，在大多数生物体用来产生能量分子ATP的四种方法中，芽囊原虫在其基因组中包含所有四种方法。在大多数情况下，一个有机体只有一个。为了了解芽囊原虫产生能量的原因和方式，我们将结合细胞生物学和生物化学技术来描述所有这些途径。了解芽囊原虫MRO在正常线粒体、氢小体和有丝分裂体间的独特桥梁性质将使其成为进一步研究其他生物中发现的线粒体的模式生物。此外，该项目将产生的基础研究和知识将有利于生物技术研究，在生物技术研究中，这些知识可用于生物材料的生产(例如，维生素的厌氧生产)或用于抗寄生虫化合物的药物开发的生物医学。

Blastocystis is a parasitic organism commonly found in samples taken from people and other animals suffering from stomach illnesses. It is a microscopic organism, which can only survive in an environment completely devoid of oxygen. This alone, highlights Blastocystis as unusual, because none of the organisms it is closely genetically related to are negatively affected by an oxygenated environment. The peculiarity of Blastocystis has been shown in several research reports where unusual structures within Blastocystis have been observed, which have been reported as "mitochondrion-related organelles" (MROs). MROs are similar in shape, but have been predicted to be in different protein composition than typical mitochondria. There are several types of irregular mitochondria among parasitic organisms, the most commonly known are hydrogenosomes (producing molecular hydrogen) and mitosomes (with unknown functions). The MROs in Blastocystis fits neither category completely, but instead displays features of both, as well as normal mitochondria.The proposed research will endeavour to unravel the mystery surrounding this bizarre organism and its equally strange internal structures. Using modern biochemical and proteomic techniques, we will seek to identify proteins within Blastocystis that function into its peculiar mitochondria. The framework of this investigation is based on previous experiments, which, although successful in predicting many proteins and metabolic pathways, produced mainly hypothetical and inconclusive results. By scaling up the experiments, growing Blastocystis under different atmospheric conditions and the use of alternative complementation systems, we will determine the functions of such hypothetical proteins. Moreover, environmental conditions that will be investigated include observations of protein concentrations alternations and functions in relation to changes in the oxygen content of the organism's environment. As a parasite, this organism is routinely exposed to oxygen when transferred between hosts, so we will investigate how Blastocystis survives during this transition. Similarly we will investigate the effects of iron concentration in the environment in order to investigate how Blastocystis retrieves the iron it requires for forming different complexes important to the function of many of its proteins.To add to the mystery that is Blastocystis, it has also been shown that out of the four methods that most organisms use to produce the energy molecule ATP, Blastocystis contains all four within its genome. In most cases an organism will only have one. To discover why and how Blastocystis has so many different methods of generating energy we will characterise all these pathways using a combination of cell biological and biochemical techniques. Understanding the unique bridging nature of the Blastocystis MROs between canonical mitochondria, hydrogenosomes and mitosomes will allow Blastocystis to be established as a model organism for the further investigation of mitochondria found in other organisms. In addition, the fundamental research and knowledge that this project will produce, will benefit both research in biotechnology, where this knowledge can be used for the production of biomaterials (for example anaerobic production of Vitamins) or in biomedicine for drug-development of anti-parasitic compounds.