Schroeder Wheaton L, Harris Steven D, Saha Rajib
Department of Chemical and Biomolecular Engineering, University of Nebraska - Lincoln, Lincoln, NE 68588, USA.
Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
iScience. 2020 Apr 24;23(4):100980. doi: 10.1016/j.isci.2020.100980. Epub 2020 Mar 13.
The polyextremotolerant black yeast Exophiala dermatitidis is a tractable model system for investigation of adaptations that support growth under extreme conditions. Foremost among these adaptations are melanogenesis and carotenogenesis. A particularly important question is their metabolic production cost. However, investigation of this issue has been hindered by a relatively poor systems-level understanding of E. dermatitidis metabolism. To address this challenge, a genome-scale model (iEde2091) was developed. Using iEde2091, carotenoids were found to be more expensive to produce than melanins. Given their overlapping protective functions, this suggests that carotenoids have an underexplored yet important role in photo-protection. Furthermore, multiple defensive pigments with overlapping functions might allow E. dermatitidis to minimize cost. Because iEde2091 revealed that E. dermatitidis synthesizes the same melanins as humans and the active sites of the key tyrosinase enzyme are highly conserved this model may enable a broader understanding of melanin production across kingdoms.
多极端耐逆性黑酵母皮炎外瓶霉是用于研究支持在极端条件下生长的适应性的一个易于处理的模型系统。这些适应性中最主要的是黑色素生成和类胡萝卜素生成。一个特别重要的问题是它们的代谢生产成本。然而，对这个问题的研究受到了对皮炎外瓶霉代谢相对较差的系统水平理解的阻碍。为了应对这一挑战，开发了一个基因组规模模型（iEde2091）。使用iEde2091发现，类胡萝卜素的生产成本比黑色素更高。鉴于它们重叠的保护功能，这表明类胡萝卜素在光保护中具有尚未充分探索但很重要的作用。此外，具有重叠功能的多种防御色素可能使皮炎外瓶霉将成本降至最低。因为iEde2091揭示皮炎外瓶霉合成的黑色素与人类相同，并且关键酪氨酸酶的活性位点高度保守，所以这个模型可能有助于更广泛地理解跨王国的黑色素生成。
