Amino-functionalized macroporous silica for efficient tryptic digestion in acidic solutions

Amino-functionalized macroporous silica foam (NH2-MOSF) has been developed as a host reactor to realize highly efficient proteolysis in acidic solutions where normal tryptic reactions cannot occur. The digestion protocol consists simply of adding the functionalized NH2-MOSF into the protein and trypsin solutions without altering the bulk pH or preloading the enzymes on the materials. With this protocol, digestion of sample fractions from LC can be efficiently realized in the acidic solutions directly. Digestion of a protein fraction extracted from rat liver tissue after LC separation was performed to illustrate this principle, where 103 proteins were successfully identified at pH 3 after 1.5 h of tryptic digestion

Proteolysis in microfluidic droplets: an approach to interface protein separation and peptide mass spectrometry

A versatile microreactor protocol based on microfluidic droplets has been developed for on-line protein digestion. Proteins separated by liquid chromatography are fractionated in water-in-oil droplets and digested in sequence. The microfluidic reactor acts also as an electrospray ionization emitter for mass spectrometry analysis of the peptides produced in the individual droplets. Each droplet is an enzymatic micro-reaction unit with efficient proteolysis due to rapid mixing, enhanced mass transfer and automated handling. This droplet approach eliminates sample loss, cross-contamination, non-specific absorption and memory effect. A protein mixture was successfully identified using the droplet-based micro-reactor as interface between reverse phase liquid chromatography and mass spectrometry

Deciphering the origin of the Cenozoic intracontinental rifting and volcanism in eastern China using integrated evidence from the Jianghan Basin

Intracontinental rifting and low-volume volcanism are a globally common phenomenon, yet the underlying driving mechanisms and whether they can be explained through classic plate tectonic concepts, remain hotly debated. A prominent example is the Cenozoic rift and volcanic province in eastern China. Using an integration of geological, geophysical and geochemical data, we unravel the spatial and temporal variations of the rifting and volcanism in the Jianghan Basin. Both rifting and volcanism in the Jianghan Basin show two intense-to-weak cycles (65–50 Ma and 50–26 Ma, respectively) with significant enhancement in activity during the late rift phase. Moreover, rifting and depocentres progressively migrated eastward. The Jianghan basalts all share an asthenospheric origin while the source of the late phase basalts is slightly more enriched and heterogenous in Nd-Hf isotopes than that of the early phase basalts. The late phase basalts also display a smaller extent of partial melting even under a thinner lithosphere, likely indicating a significant decrease of volatile content in the mantle source. Based on regional tectonic correlations, the main stages of tectonic evolution of the Jianghan Basin and eastern China are not synchronous with changes in Pacific plate motion, while they are coincident with India-Asia collision processes. These observations lead us to propose that the asthenospheric flow driven by India-Asia collision rather than the rollback of the subducted Pacific slab has caused the widespread rifting and volcanism in eastern China. The variations of rifting and volcanism in the Jianghan Basin suggest a multiphase and eastward asthenospheric flow beneath eastern China driven by India-Asia collision, with an intense upwelling when passing through the North-South Gravity Lineament (NSGL). The much more intense rifting and volcanism during the late rift phase may indicate a much larger scale of volatile-poor asthenospheric flow than the early rift phase which could result in a more intense erosion of ancient enriched lithospheric mantle and the volatile content in the mantle source dropping sharply. This study provides an improved model based on our multidisciplinary observations for asthenospheric flow which may be an alternative driving mechanism for intracontinental rifting and low-volume volcanism in the regions where there are step changes in lithospheric thickness globally

Structural features and deformational ages of the northern Dabashan thrust belt

A large-scale pop-up structure occurs at the front of the northern Dabashan thrust belt (NDTB), bound by the NNE-dipping Chengkou fault to the south, and the SSW-dipping Gaoqiao fault to the north. The pop-up structure shows different features along its strike as a direct reflection of the intensity of tectonic activity. To the northwest, the structure is characterized by a two-directional thrust system forming a positive flower-like structure. In contrast, the southeastern part is composed of the vertical Chengkou fault and a series of N-directed backthrusts, showing a semi-flower-like structure. We present results from Ar-Ar dating of syntectonic microthermal metamorphic sericite which show that the Chengkou fault experienced intense deformation during the mid-Mesozoic Yanshanian epoch (about 143.3 Ma), causing rapid uplift and thrusting of the northern Dabashan thrust belt. During the propagation of this thrust, a series of backthrusts formed because of the obstruction from the frontier of Dabashan thrust belt, leading to the development of the pop-up structure