Marine Biological Laboratory, Ecosystems Center, Woods Hole, Massachusetts, 02543, USA.
Department of Chemical Engineering, University of Wyoming, Laramie, Wyoming, 82071, USA.
J Phycol. 2022 Aug;58(4):626-630. doi: 10.1111/jpy.13271. Epub 2022 Jul 1.
Microalgae within the Scenedesmaceae are often distinguished by spines, bristles, and other wall characteristics. We examined the dynamic production and chemical nature of bristles extruded from the poles of Tetradesmus deserticola previously isolated from microbiotic crust. Rapidly growing cells in a liquid growth medium were established in polydimethylsiloxane microfluidic chambers specially designed to maintain aerobic conditions over time within a chamber 6-12 μm deep. This geometry enabled in-focus imaging of single cells over long periods. Differential interference contrast (DIC) imaging revealed that after multiple fission of mother cells, the newly released, lemon-shaped daughter cells began extruding bristles from each pole. In some instances, the bristles became stuck to either the glass floor or polydimethylsiloxane (PDMS) walls of the chamber, and the force by which the new bristle was extruded was sufficient to propel the cells across the field of view at ~1.2 μm · h . Confocal fluorescence and DIC imaging of cells stained with pontamine fast scarlet and calcofluor, and treated with proteinase K, suggested that bristles are proteinaceous and may also host carbohydrate modifications. The polar bristles extruded by this desert-derived T. deserticola may simply be relics of bristles produced by an aquatic ancestor for flotation or predator deterrence. But, their tendency to attach to glass (silicate) and/or PDMS surfaces suggests a potential role in tethering cells in place or binding soil particles. T. deserticola is closely related to T. obliquus, which is of interest for biofuels development; extruded bristles in T. deserticola may offer tethers for industrial use of these stress-tolerant algae.
微藻中的栅藻科通常以刺、刚毛和其他细胞壁特征来区分。我们研究了先前从微生物结皮中分离出的沙漠栅藻极区挤出的刚毛的动态产生和化学性质。在专门设计的聚二甲基硅氧烷微流控室内的液体生长培养基中，快速生长的细胞可以在室内长时间保持有氧条件，该室深 6-12μm。这种几何形状使我们能够对单个细胞进行长时间的聚焦成像。微分干涉对比（DIC）成像显示，在母细胞多次分裂后，新释放的、柠檬形的子细胞开始从每个极挤出刚毛。在某些情况下，刚毛会粘在室的玻璃底板或聚二甲基硅氧烷（PDMS）壁上，并且新刚毛挤出的力足以将细胞推进视场，速度约为 1.2μm·h。用孔雀快速猩红和钙荧光素染色并用蛋白酶 K处理的细胞的共聚焦荧光和 DIC 成像表明，刚毛是蛋白质性质的，并且可能还含有碳水化合物修饰物。这种来自沙漠的 T. deserticola 极区挤出的极性刚毛可能只是水生祖先为漂浮或防止捕食者而产生的刚毛的遗迹。但是，它们附着在玻璃（硅酸盐）和/或 PDMS 表面的趋势表明它们可能在将细胞固定在原位或结合土壤颗粒方面具有潜在的作用。T. deserticola 与 T. obliquus 密切相关，后者对生物燃料的开发很感兴趣；T. deserticola 中挤出的刚毛可能为这些耐应激藻类的工业用途提供系绳。
