Graphitic Armor: A Natural Molecular Sieve for Robust Hydrogen Electroxidation.

Carbon coating layers have been found to improve the catalytic performance of transition metals, which is usually explained as an outcome of electronic synergistic effect. Herein we reveal that the defective graphitic carbon, with a unique interlayer gap of 0.342 nm, can be a highly selective natural molecular sieve. It allows efficient diffusion of hydrogen molecules or radicals both along the in-plane and out-of-plane direction, but sterically hinders the diffusion of molecules with larger kinetic diameter (e.g., CO and O2) along the in-plane direction. As a result, poisonous species lager than 0.342 nm are sieved out, even when their adsorption on the metal is thermodynamically strong; at the same time, the interaction between H2 and the metal is not affected. This natural molecular sieve provides a very chance for constructing robust metal catalysts for hydrogen-relevant processes, which are more tolerant to chemical or electrochemical oxidation or CO-relevant poisoning.

Selenium-enriched Polysaccharides from Pyracantha fortuneana (SePFP) Ameliorated Hepatic Lipid Accumulation through Enhancing Mitochondrial Fatty Acid ß-Oxidation in Aging Mice.

Selenium-enriched polysaccharides from Pyracantha fortuneana (SePFP) has many beneficial physiological activities, but how it improves the aging associated abnormal lipid metabolism is still unclear. Therefore, we explored the mechanisms of the regulatory role of SePFP on liver lipid accumulation in aging mice. METHODS: 60 naturally aged C57BL/6J male mice were divided into 6 groups: adult group, aging group (21-month-old mice), aging mice treated with low-, medium- and high-doses of SePFP (SePFP-L, SePFP-M, SePFP-H), and aging mice treated with resveratrol (RSV). SePFP and RSV were administrated daily via oral gavage from 16 to 21 months old. The parameters of energy metabolism were measured in all mice before sacrifice, and liver tissues were collected to determine the levels of metabolism-related enzymes by real-time PCR and Western blot. RESULTS: We found that SePFP significantly reduced the body weight, liver to bodyweight ratio, and white fat to body weight ratio in aging mice. SePFP also down-regulated the triglycerides and cholesterol levels in liver and serum, and decreased respiratory quotient in aging mice. The mechanism of SePFP regulating lipid metabolism was mainly through promoting fatty acid transportation to mitochondria and enhancing mitochondrial ß-oxidation and ketone body production. CONCLUSION: SePFP attenuates liver lipid deposition in aging mice by enhancing hepatic mitochondrial ß-oxidation.

[Research on simulation and optimal design of a miniature magnetorheological fluid damper used in wearable rehabilitation training system].

The goal of this paper is to solve the problems of large volume, slow dynamic response and poor intelligent controllability of traditional gait rehabilitation training equipment by using the characteristic that the shear yield strength of magnetorheological fluid changes with the applied magnetic field strength. Based on the extended Bingham model, the main structural parameters of the magnetorheological fluid damper and its output force were simulated and optimized by using scientific computing software, and the three-dimensional modeling of the damper was carried out after the size was determined. On this basis and according to the design and use requirements of the damper, the finite element analysis software was used for force analysis, strength check and topology optimization of the main force components. Finally, a micro magnetorheological fluid damper suitable for wearable rehabilitation training system was designed, which has reference value for the design of lightweight, portable and intelligent rehabilitation training equipment.

[Effects of Spartina alterniflora invasion on the functional groups and niche of benthic crustaceans and fishes in mangrove wetland.] / äº’èŠ±ç±³è‰å ¥ä¾µå¯¹çº¢æ ‘æž—åº•æ –ç”²å£³åŠ¨ç‰©å’Œé±¼ç±»åŠŸèƒ½ç¾¤åŠç”Ÿæ€ä½çš„å½±å“.

To investigate the effects of Spartina alterniflora invasion on mangrove wetland ecosystem, the benthic crustacean and fish samples were collected using cage nets in Zhangjiang Estuary Mangrove Wetland, Fujian Pro-vince in August 2020, January and April 2021. The five sampling sites included two mangroves (Avicennia marina and Kandelia obovata) sites, two S. alterniflora sites, and one mudflat site. The abundance, biomass, index of relative importance (IRI), Shannon diversity index (H), Pielou evenness index (J), and Margalef richness index (D) were used to quantify the dominant species and species diversity of benthic crustaceans and fishes. The functional groups and niche of dominant species were also analyzed. A total of 37 species, from 2 phyla, 2 classes, 8 orders, and 17 families, were identified across the three seasons. Most of them were warm-water and euryhaline species, mainly carnivorous and omnivorous functional groups. The results of two-way analysis of variance and NMDS showed that the community diversity index of benthic crustacean and fish did not change significantly after the invasion of S. alterniflora compared with mudflat. Functional groups had changed significantly, with the species number of plankton functional groups, carnivorous and phytophagous functional groups being increased. Compared with mangrove sites, the number of species of benthic crustacean and fish in S. alterniflora sites was significantly increased. The spatio-temporal niche breadth of dominant species ranged from 0 to 1.4186, with Liza carinata (1.4186), Bostrychus sinensis (1.0168), Metapenaeus ensis (0.9469) and Exopalaemon carinicauda (0.8922) as the top four species.

Development of a primary culture system for haematopoietic tissue cells from Cherax quadricarinatus and an exploration of transfection methods.

Various known and unknown viral diseases can threaten crustacean aquaculture. To develop prophylactic and therapeutic strategies against viruses, crustacean cell lines are urgently needed for immunology and virology studies. However, there are currently no permanent crustacean cell lines available. In this study, we developed a new method for preparing crayfish plasma (CP) and found that CP enhanced the proliferative capacity of haematopoietic tissue (hpt) cells from Cherax quadricarinatus by an EdU (5-ethynyl-2'-deoxyuridine) assay. The optimal CP concentration for hpt cell culture and the optimal subculture method are discussed. To achieve efficient expression of a foreign gene in hpt cells cultured in vitro, different transfection methods and vectors were analysed. We found that Lipofectamine 2000 could be used to efficiently transfect a foreign vector into hpt cells and exhibited a lower level of cytotoxicity than the other methods tested, and transfection of pEGFP-N1/w249 and pDHsp70-EGFP-FLAG resulted in high EGFP expression. By transmission electron microscopy (TEM) and virus copy number analysis, we found that white spot syndrome virus (WSSV) could infect hpt cells and multiply efficiently. Our results implied that the crayfish hpt cell culture system we improved could be used as a replacement for immortal crustacean cell lines in viral infection studies. Our findings provide a solid foundation for future immortalization and gene function studies in crustacean cells.

CRISPR/Cas9-Mediated Genome Editing and Mutagenesis of EcChi4 in Exopalaemon carinicauda.

The development of the type II clustered regularly interspaced short palindromic repeats (CRISPR) system has resulted in the revolution of genetic engineering, and this technology has been applied in the genome editing of various species. However, there are no reports about target-specific genome editing in shrimp. In this research, we developed a microinjection method for the ridgetail white prawn Exopalaemon carinicauda and successfully applied CRISPR/Cas9 technology to the genome editing of E. carinicauda Through coinjection of mRNA of Cas9 nuclease and gRNA specialized for E. carinicauda chitinase 4 (EcChi4), shrimps with indel mutations were obtained. Further analysis showed that the mutations could be transmitted to the next generation. This is the first time that site-specific genome editing has been successfully demonstrated in a decapod, and will further contribute to the study of functional genomics in decapods.

Identification and function analysis of a novel vascular endothelial growth factor, LvVEGF3, in the Pacific whiteleg shrimp Litopenaeus vannamei.

VEGF signaling pathway is first discovered in mammals and proved to play important roles in the biological processes of angiogenesis, tumor migration, cell differentiation, apoptosis, host-virus interaction etc. Three members in the VEGF signaling pathway, including LvVEGFR, LvVEGF1 and LvVEGF2 in shrimp have been proved to be related with WSSV infection in our previous studies. Currently, another member of VEGF family, LvVEGF3, was isolated and its function during the WSSV infection of shrimp was studied. The deduced amino acid sequence of LvVEGF3 contained a signal peptide, a typical PDGF/VEGF domain and a cysteine-knot motif (CXCXC). Tissue distribution analysis showed that LvVEGF3 was predominantly expressed in hemocytes. The transcriptional level of LvVEGF3 in hemocytes was apparently up-regulated during WSSV infection. Silencing of LvVEGF3 with double-stranded RNA caused a reduction of the cumulative mortality rate of shrimp during WSSV infection. The expression of LvVEGFR was apparently down-regulated after LvVEGF3 silencing and up-regulated after injection of recombinant LvVEGF3 protein, suggesting an interaction between LvVEGF3 and LvVEGFR. Furthermore, the interaction between LvVEGFR and LvVEGF3 was confirmed using the yeast two-hybrid system. The results provided new insights into understanding the role of VEGF signaling pathway during virus infection.

Envelope Proteins of White Spot Syndrome Virus (WSSV) Interact with Litopenaeus vannamei Peritrophin-Like Protein (LvPT).

White spot syndrome virus (WSSV) is a major pathogen in shrimp cultures. The interactions between viral proteins and their receptors on the surface of cells in a frontier target tissue are crucial for triggering an infection. In this study, a yeast two-hybrid (Y2H) library was constructed using cDNA obtained from the stomach and gut of Litopenaeus vannamei, to ascertain the role of envelope proteins in WSSV infection. For this purpose, VP37 was used as the bait in the Y2H library screening. Forty positive clones were detected after screening. The positive clones were analyzed and discriminated, and two clones belonging to the peritrophin family were subsequently confirmed as genuine positive clones. Sequence analysis revealed that both clones could be considered as the same gene, LV-peritrophin (LvPT). Co-immunoprecipitation confirmed the interaction between LvPT and VP37. Further studies in the Y2H system revealed that LvPT could also interact with other WSSV envelope proteins such as VP32, VP38A, VP39B, and VP41A. The distribution of LvPT in tissues revealed that LvPT was mainly expressed in the stomach than in other tissues. In addition, LvPT was found to be a secretory protein, and its chitin-binding ability was also confirmed.