Subpollen particles (SPP) of birch as carriers of ice nucleating macromolecules
Subpollen particles (SPP) of birch as carriers of ice nucleating macromolecules
复制标题
桦木亚花粉颗粒（SPP）作为冰成核大分子的载体
DOI：
--
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
H. Grothe
中科院分区：
文献类型：
--
作者：
Julia Burkart;Jürgen Gratzl;T. Seifried;P. Bieber;H. Grothe
<p>风媒传粉的树木，如桦树，在早春开花季节向大气中释放大量花粉。由于花粉体积大（桦树花粉直径：20-25米），在大气中停留时间短，它们对云形成的影响被认为是微不足道的。然而，近年来的研究表明，可以从花粉中提取尺寸小得多的冰成核物质，即所谓的冰成核大分子（INM）。与此同时，医学研究表明，花粉在大气中高湿度的条件下可以破裂，并排出细胞质物质，包括淀粉颗粒，通常称为亚花粉颗粒（SPP）。INM或SPP比花粉小得多，可能比花粉多得多，可以显著影响大气中的云的形成。</p><p>本研究以桦树花粉为材料，探讨花粉粒与INM和SPP之间的关系。根据SPP一词在医学领域的用法，我们将SPP定义为花粉粒中含有的淀粉颗粒。我们开发了一种提取方法来产生大量的SPP，并研究其冰核活性。据我们所知，这是第一次研究孤立的SPP的冰核活性。我们表明，INM只是松散地附着到SPP和纯化的SPP是没有冰核活性：用超纯水洗涤SPP几次后，冰核活性完全消失。此外，我们研究了化学性质的INM与荧光光谱和量化的蛋白质浓度与Bradford测定。荧光激发-发射图表明在蛋白质范围内的强信号（<sub>在ex</sub>= 280 nm和<sub>em</sub>= 330 nm附近最大），其与冰成核活性相关。相反，用纯化的SPP，该信号丢失。蛋白质浓度范围从高浓度INM的77.4g mL<sup>-1</sup>到纯化SPP的低于2.5g mL<sup>-1</sup>。因此，结果表明冰成核活性和蛋白质浓度之间的联系。纯化的SPP不具有冰核活性，但可以作为INM的载体并将其分布在大气中。</p>
<p>Wind pollinated trees such as birch trees release large amounts of pollen to the atmosphere during their blooming season in early spring. Due to the large size of pollen (birch pollen diameter: 20-25 µm) and short residence time in the atmosphere, their impact on cloud formation was believed to be negligible. However, in recent years studies have shown that ice nucleating materials, so called ice nucleating macromolecules (INM), much smaller in size can be extracted from pollen. At the same time there is evidence from medical studies that pollen can rupture under conditions of high humidity in the atmosphere and expel cytoplasmic material including starch granules, commonly referred to as subpollen particles (SPP). INM or SPP are much smaller and potentially more numerous than pollen and could significantly affect cloud formation in the atmosphere.</p><p>In this study, we focus on birch pollen and investigate the relationship between pollen grains, INM and SPP. According to the usage of the term SPP in the medical field we define SPP as the starch granules contained in pollen grains. We develop an extraction method to generate large quantities of SPP and investigate their ice nucleation activity. To our knowledge, this is the first study to investigate the ice nucleation activity of isolated SPP. We show that INM are only loosely attached to SPP and that purified SPP are not ice nucleation active: after several times of washing SPP with ultrapure water the ice nucleation activity completely disappears. In addition, we study the chemical nature of the INM with fluorescence spectroscopy and quantify the protein concentration with the Bradford assay. Fluorescence excitation-emission maps indicate a strong signal in the protein range (maximum around λ<sub>ex</sub> = 280 nm and λ<sub>em</sub> = 330 nm) that correlates with the ice nucleation activity. In contrast, with purified SPP this signal is lost. The protein concentration ranges from 77.4 μg mL<sup>-1</sup> for highly concentrated INM to below 2.5 μg mL<sup>-1</sup> for purified SPP. The results thereby indicate a linkage between ice nucleation activity and protein concentration. Purified SPP are not ice nucleation active but could, however, act as carriers of INM and distribute those in the atmosphere.</p>
影响因子：
14.2
作者：
Bacsi, Attila;Choudhury, Barun K.;Boldogh, Istvan
通讯作者：
Boldogh, Istvan
影响因子：
3.8
作者：
H. Tong;B. Ouyang;N. Nikolovski;D. Lienhard;F. Pope;M. Kalberer
通讯作者：
H. Tong;B. Ouyang;N. Nikolovski;D. Lienhard;F. Pope;M. Kalberer