Ultrafast interfacial charge evolution of the Type-II cadmium Sulfide/Molybdenum disulfide heterostructure for photocatalytic hydrogen production.

The interfacial charge dynamics was crucial for semiconductor heterostructure photocatalysis. Through the rational design of the heterostructure interface, heterojunction expressed variable recombination and migration dynamics for excited carriers. Herein, followed by a typical chemical bath strategy with the hexagonal cadmium sulfide (CdS) overlapped on the exfoliated molybdenum disulfide (MoS2) film, we developed a cadmium sulfide/molybdenum disulfide (CdS-MoS2) nano-heterojunction and investigated the interfacial charge dynamics for photocatalytic hydrogen evolution. Photoelectron spectroscopy detected an energetic offset between CdS and MoS2, revealing the formation of an interfacial electric field with efficient charges separation. Through transient absorption spectra, we demonstrated the type-II contact at the CdS-MoS2 interface. Driven by the electric field, the excited carriers separated and rapidly migrated to sub-band defects of CdS within the first 500 fs. The carriers-restricted defects provided catalytic active sites, endowing CdS-MoS2 a highly efficient photocatalytic capability. Consequentially, the CdS-MoS2 achieved an enhanced hydrogen evolution rate of 2.3 mmol·g-1·h-1 with significantly stronger photocurrent density. This work gave an insight to the channel of interfacial separation and migration for excited carriers, which could contribute to the interfacial engineering of advanced heterojunction photocatalysts.

Comprehensively dissecting the hub regulation of PkaC on high-productivity and pellet macromorphology in citric acid producing Aspergillus niger.

Aspergillus niger, an important industrial workhorse for citric acid production, is characterized by polar hyphal growth with complex pelleted, clumped or dispersed macromorphologies in submerged culture. Although organic acid titres are dramatically impacted by these growth types, studies that assess productivity and macromorphological changes are limited. Herein, we functionally analysed the role of the protein kinase A (PKA)/cyclic adenosine monophosphate (cAMP) signalling cascade during fermentation by disrupting and conditionally expressing the pkaC gene. pkaC played multiple roles during hyphal, colony and conidiophore growth. By overexpressing pkaC, we could concomitantly modify hyphal growth at the pellet surface and improve citric acid titres up to 1.87-fold. By quantitatively analysing hundreds of pellets during pilot fermentation experiments, we provide the first comprehensive correlation between A. niger pellet surface morphology and citric acid production. Finally, by intracellular metabolomics analysis and weighted gene coexpression network analysis (WGCNA) following titration of pkaC expression, we unveil the metabolomic and transcriptomic basis underpin hyperproductivity and pellet growth. Taken together, this study confirms pkaC as hub regulator linking submerged macromorphology and citric acid production and provides high-priority genetic leads for future strain engineering programmes.

Total Alkaloids from Bamboo Shoots and Bamboo Shoot Shells of Pleioblastus amarus (Keng) Keng f. and Their Anti-Inflammatory Activities.

The bamboo shoot of Pleioblastus amarus (Keng) Keng f. is a medicinal and edible plant product in China. In this study, the chemical composition of the total alkaloids from bamboo shoots and bamboo shoot shells of P. amarus (Keng) Keng f. (ABSP and ABSSP, respectively) were separated and investigated by UHPLC/QTOF-MS/MS. The results showed that a total of 32 alkaloids were extracted, with 15 common to both ABSP and ABSSP and 10 and 7 alkaloids distinct to ABSP and ABSSP, respectively. ABSP and ABSSP both decreased the lipopolysaccharide (LPS, 0.5 µg/mL)-induced nitric oxide (NO) production in RAW264.7 murine macrophages with half maximal inhibitory concentration (IC50) values of 78 and 55 µg/mL, respectively. We also found that ABSP and ABSSP (100 µg/mL) could decrease the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at both mRNA and protein levels in LPS-exposed RAW264.7 cells. Moreover, 100 µg/mL of ABSP and ABSSP also significantly inhibited LPS-induced mRNA expression of interleukin 1ß (IL-1ß) and tumor necrosis factor α (TNF-α). Additionally, ABSP and ABSSP (100 µg/mL) decreased the phosphorylation of extracellular regulated protein kinase (ERK) in LPS-stimulated RAW264.7 cells. Collectively, the total alkaloids from the bamboo shoots and shells of P. amarus exhibit anti-inflammatory effects in LPS-activated RAW264.7 cells through the inhibition of ERK signaling. This result can provide support for the medicinal use and further study of P. amarus.