Micheluz Anna, Pinzari Flavia, Rivera-Valentín Edgard G, Manente Sabrina, Hallsworth John E
Conservation Science Department, Deutsches Museum, Museumsinsel 1, 80538 Munich, Germany.
Institute for Biological Systems, Council of National Research of Italy, Area della Ricerca di Roma 1, Via Salaria Km 29,300, 00015 Monterotondo, Italy.
Pathogens. 2022 Dec 2;11(12):1462. doi: 10.3390/pathogens11121462.
is psychrotolerant, halophilic, and one of the most-extreme xerophiles in Earth's biosphere. We already know that this ascomycete grows close to 0 °C, at high NaCl, and-under some conditions-down to 0.651 water-activity. However, there is a paucity of information about how it achieves this extreme stress tolerance given the dynamic water regimes of the surface habitats on which it commonly occurs. Here, against the backdrop of global climate change, we investigated the biophysical interactions of with its extracellular environment using samples taken from the surfaces of library books. The specific aims were to examine its morphology and extracellular environment (using scanning electron microscopy for visualisation and energy-dispersive X-ray spectrometry to identify chemical elements) and investigate interactions with water, ions, and minerals (including analyses of temperature and relative humidity conditions and determinations of salt deliquescence and water activity of extracellular brine). We observed crystals identified as eugsterite (NaCa(SO)·2HO) and mirabilite (NaSO·10HO) embedded within extracellular polymeric substances and provide evidence that uses salt deliquescence to maintain conditions consistent with its water-activity window for growth. In addition, it utilizes a covering of hair-like microfilaments that likely absorb water and maintain a layer of humid air adjacent to the hyphae. We believe that, along with compatible solutes used for osmotic adjustment, these adaptations allow the fungus to maintain hydration in both space and time. We discuss these findings in relation to the conservation of books and other artifacts within the built environment, spoilage of foods and feeds, the ecology of in natural habitats, and the current episode of climate change.
具有耐冷性、嗜盐性，是地球生物圈中最极端的嗜旱生物之一。我们已经知道这种子囊菌在接近0°C、高NaCl浓度以及某些条件下低至0.651水活度的环境中生长。然而，鉴于其常见的表面栖息地动态水情，关于它如何实现这种极端胁迫耐受性的信息却很少。在此，在全球气候变化的背景下，我们使用从图书馆书籍表面采集的样本，研究了它与其细胞外环境的生物物理相互作用。具体目标是检查其形态和细胞外环境（使用扫描电子显微镜进行可视化，能量色散X射线光谱法识别化学元素），并研究与水、离子和矿物质的相互作用（包括温度和相对湿度条件分析以及细胞外盐水的盐潮解和水活度测定）。我们观察到在细胞外聚合物中嵌入了被鉴定为水钠钙矾（NaCa(SO)·2H₂O）和芒硝（Na₂SO₄·10H₂O）的晶体，并提供证据表明它利用盐潮解来维持与其生长的水活度窗口一致的条件。此外，它利用一层毛发状微丝覆盖物，这可能吸收水分并在菌丝附近维持一层潮湿空气。我们认为，连同用于渗透调节的相容性溶质一起，这些适应性使真菌能够在空间和时间上维持水合作用。我们将这些发现与建筑环境中书和其他文物的保护、食品和饲料的变质、自然栖息地中它的生态学以及当前的气候变化事件联系起来进行讨论。
