ABSTRACT
Online analysis of the composition and evolution of complex oligomeric intermediates in biomass degradation is highly desirable to elucidate the mechanism of bond cleavage and study the effect of conditions on the selective conversion of feedstocks. However, harsh reaction conditions and complicated conversion systems pose tremendous challenges for conventional, state-of-the-art analytical techniques. Herein, we introduce a continuous and rapid compositional analysis strategy coupling a high-pressure flow-through reactor with online high-resolution mass spectrometry, which enables the molecular-level characterization of most biomass-related products throughout the conversion for over 2 h. Catalytic depolymerization of one model compound was studied, and temperature-dependent data of over 50 intermediates as well as recondensation dimers and oligomers were obtained, which have rarely been reported in the literature. Thousands of products during the flow-through conversion of birch wood with molecular weights up to 1000 Da were presented, and 8 typical lignin dimers and oligomers with various interunit linkages were identified at the molecular level, demonstrating the potential to analyze more complicated systems far beyond conventional methods, especially for complex oligomers. The continuous evolutions of different components and typical products were unveiled for the first time, providing valuable insights into the investigation of the structure, composition, and decomposition mechanism of lignocellulose as well as the influence of reaction conditions. This method leads to the previously unattained ability to probe and reveal complicated chemical compositions in high-pressure reactions and can be applied to all other high-pressure heterogeneous aqueous reactions.
ABSTRACT
The centrosome linker serves to hold the duplicated centrosomes together until they separate in late G2/early mitosis. Precisely how the linker is assembled remains an open question. In this study, we identify Cep44 as a novel component of the linker in human cells. Cep44 localizes to the proximal end of centrioles, including mother and daughter centrioles, and its ablation leads to loss of centrosome cohesion. Cep44 does not impinge on the stability of C-Nap1 (also known as CEP250), LRRC45 or Cep215 (also known as CDK5RAP2), and vice versa, and these proteins are independently recruited to the centrosome. Rather, Cep44 associates with rootletin and regulates its stability and localization to the centrosome. Our findings reveal a role of the previously uncharacterized protein Cep44 for centrosome cohesion and linker assembly.