Tokarz Danielle, Cisek Richard, Krouglov Serguei, Kontenis Lukas, Fekl Ulrich, Barzda Virginijus
Department of Chemical and Physical Sciences, University of Toronto Mississauga , 3359 Mississauga Road North, Mississauga, Ontario, Canada L5L 1C6.
J Phys Chem B. 2014 Apr 10;118(14):3814-22. doi: 10.1021/jp411387p. Epub 2014 Mar 27.
Polarization-in, polarization-out (PIPO) second harmonic generation (SHG) and third harmonic generation (THG) microscopy was used to study the crystalline organization of β-carotene molecules within individual aggregates contained in the chromoplasts of orange carrots in vivo. Multimodal PIPO SHG and PIPO THG studies of the aggregates revealed one dominant SHG and THG dipole signifying that β-carotene molecules are oriented along a single axis. Three-dimensional visualization of the orientation of β-carotene molecules with respect to the aggregate axis was also performed with both microscopy modalities and revealed organization of the aggregates as ribbon-like structures consisting of twists and folds. Therefore, PIPO SHG and PIPO THG microscopy provides information on the crystalline organization and the orientation of ordered biological structures in vivo where multimodal polarization dependent SHG and THG investigations are particularly advantageous as both noncentrosymmetric and centrosymmetric crystalline organizations can be probed.
偏振入射-偏振出射（PIPO）二次谐波产生（SHG）和三次谐波产生（THG）显微镜被用于研究体内橙色胡萝卜质体中单个聚集体内β-胡萝卜素分子的晶体结构。对聚集体的多模态PIPO SHG和PIPO THG研究揭示了一个主要的SHG和THG偶极，表明β-胡萝卜素分子沿单轴取向。还使用这两种显微镜模式对β-胡萝卜素分子相对于聚集体轴的取向进行了三维可视化，并揭示聚集体组织为具有扭曲和褶皱的带状结构。因此，PIPO SHG和PIPO THG显微镜提供了关于体内有序生物结构的晶体结构和取向的信息，其中多模态偏振相关的SHG和THG研究特别有利，因为非中心对称和中心对称的晶体结构都可以被探测。
