Interactions between the gut bacterial community of Exopalaemon carinicauda and infection by Enterocytozoon hepatopenaei.

To explore the relationship between the intestinal flora of Exopalaemon Carinicauda and infection by Enterocytozoo Hepatopenaei (EHP), we analyzed the species and richness of gut microbiota in infected individuals in different EHP load groups [i.e., control (C), high load (H), and low load (L)] using gene sequencing after infection. The results showed that the abundance of intestinal flora in the high-load EHP group was significantly lower than that in the healthy group. Based on the UPGMA cluster tree and PCoA analysis, with comparisons to healthy shrimp, the gut microbiota of the EHP high load and low load groups were clustered into one branch, which indicated that EHP infection changed the composition of the gut microbiota of infected shrimps. The heat map analysis of species abundance clustering revealed that the dominant bacteria in the low EHP load group and the control group were beneficial genera such as Lactococcus, Ligilactobacillius, and Bifidobacterium, but the dominant bacteria in the high EHP load group were harmful genera such as Pseudomonas, Photobacterium, and Candidatus hepatincola. The functions of the intestinal flora predicted that most genes related to metabolism were more abundant in healthy shrimp, most genes related to metabolism and the organisms' system were more abundant in the low EHP load group, and most genes related to diseases and environmental information processing were more abundant in the high EHP load group. After separation and purification, the dominant bacteria (Bifidobacterium animalis in healthy shrimp and Lactococcus garvieae in the low EHP load group) and the non-dominant bacteria (Macrococus caseolyticus in the low EHP load group) were obtained. Each of these isolated strains were used together with EHP to infect E. carinicauda, and the results showed that Bifidobacterium animali and Lactococcus garvieae significantly reduced the EHP load in EHP-infected individuals. At the same time, the morphology and structure of the hepatopancreas and intestinal tissue of EHP-infected E. carinicauda were improved. No improvement was seen in tissue that was infected with Macrococus caseolyticus.

Exploring the catalytic activity of graphene-based TM-NxC4-x single atom catalysts for the oxygen reduction reaction via density functional theory calculation.

Electrocatalysts for the oxygen reduction reaction (ORR) are extremely crucial for advanced energy conversion technologies, such as fuel cell batteries. A promising ORR catalyst usually should have low overpotentials, rich catalytic sites and low cost. In the past decade, single-atom catalyst (SAC) TM-N4 (TM = Fe, Co, etc.) embedded graphene matrixes have been widely studied for their promising performance and low cost for ORR catalysis, but the effect of coordination on the ORR activity is not fully understood. In this work, we will employ density functional theory (DFT) calculations to systematically investigate the ORR activity of 40 different 3d transition metal single-atom catalysts (SACs) supported on nitrogen-doped graphene supports, ranging from vanadium to zinc. Five different nitrogen coordination configurations (TM-NxC4-x with x = 0, 1, 2, 3, and 4) were studied to reveal how C/N substitution affects the ORR activity. By looking at the stability, free energy diagram, overpotential, and scaling relationship, our calculation showed that partial C substitution can effectively improve the ORR performance of Mn, Co, Ni, and Zn-based SACs. The volcano plot obtained from the scaling relationship indicated that the substitution of N by C could distinctively affect the potential-limiting step in the ORR, which leads to the enhanced or weakened ORR performance. Density of states and d-band center analysis suggested that this coordination-tuned ORR activity can be explained by the shift of the d-band center due to the coordination effect. Finally, four candidates with optimal ORR activity and dynamic stability were proposed from the pool: NiC4, CoNC3, CrN4, and ZnN3C. Our work provides a feasible designing strategy to improve the ORR activity of graphene-based TM-N4 SACs by tuning the coordination environment, which may have potential implication in the high-performance fuel cell development.

Enabling High Loading in Single-Atom Catalysts on Bare Substrate with Chemical Scissors by Saturating the Anchoring Sites.

Atomically dispersed metal catalysts often exhibit high catalytic performances, but the metal loading density must be kept low to avoid the formation of metal nanoparticles, making it difficult to improve the overall activity. Diverse strategies based on creating more anchoring sites (ASs) have been adopted to elevate the loading density. One problem of such traditional methods is that the single atoms always gather together before the saturation of all ASs. Here, a chemical scissors strategy is developed by selectively removing unwanted metallic materials after excessive loading. Different from traditional ways, the chemical scissors strategy places more emphasis on the accurate matching between the strength of etching agent and the bond energies of metal-metal/metal-substrate, thus enabling a higher loading up to 2.02 wt% even on bare substrate without any pre-treatment (the bare substrate without any pre-treatment generally only has a few ASs for single atom loading). It can be inferred that by combining with other traditional methods which can create more ASs, the loading could be further increased by saturating ASs. When used for CH3 OH generation via photocatalytic CO2 reduction, the as-made single-atom catalyst exhibits impressive catalytic activity of 597.8 ± 144.6 µmol h-1 g-1 and selectivity of 81.3 ± 3.8%.

Magnetic Field Manipulation of Tetrahedral Units in Spinel Oxides for Boosting Water Oxidation.

Magnetic field enhanced electrocatalysis has recently emerged as a promising strategy for the development of a viable and sustainable hydrogen economy via water oxidation. Generally, the effects of magnetic field enhanced electrocatalysis are complex including magnetothermal, magnetohydrodynamic and spin selectivity effects. However, the exploration of magnetic field effect on the structure regulation of electrocatalyst is still unclear whereas is also essential for underpinning the mechanism of magnetic enhancement on the electrocatalytic oxygen evolution reaction (OER) process. Here, it is identified that in a mixed NiFe2 O4 (NFO), a large magnetic field can force the Ni2+ cations to migrate from the octahedral (Oh ) sites to tetrahedral (Td ) sites. As a result, the magnetized NFO electrocatalyst (NFO-M) shows a two-fold higher current density than that of the pristine NFO in alkaline electrolytes. The OER enhancement of NFO is also observed at 1 T (NFO@1T) under an operando magnetic field. Our first-principles calculations further confirm the mechanism of magnetic field driven structure regulation and resultant OER enhancement. These findings provide a strategy of manipulating tetrahedral units of spinel oxides by a magnetic field on boosting OER performance.

Enhancement of Mass and Charge Transfer during Carbon Dioxide Photoreduction by Enhanced Surface Hydrophobicity without a Barrier Layer.

The CO2 reduction reaction (CRR) represents a promising route for the clean utilization of renewable resources. But mass-transfer limitations seriously hinder the forward step. Enhancing the surface hydrophobicity by using polymers has been proved to be one of the most efficient strategies. However, as macromolecular organics, polymers on the surface hinder the transfer of charge carriers from catalysts to reactants. Herein, we describe an in-situ surface fluorination strategy to enhance the surface hydrophobicity of TiO2 without a barrier layer of organics, thus facilitating the mass transfer of CO2 to catalysts and charge transfer. With less obstruction to charge transfer, a higher CO2, and lower H+ surface concentration, the photocatalytic CRR generation rate of methanol (CH3 OH) is greatly enhanced to up to 247.15 µmol g-1 h-1 . Furthermore, we investigated the overall defects; enhancing the surface hydrophobicity of catalysts provides a general and reliable method to improve the competitiveness of CRR.

Preparation and characterization of a high-affinity monoclonal antibody against human epididymis protein-4.

Human epididymis protein-4 (HE4) may serve as a putative biomarker for the early diagnosis, therapy and especially prognosis of ovarian, lung and breast cancer. Detection and targeting of HE4 using the anti-HE4 antibody could be one of the effective strategies for the cancer diagnosis and treatment in clinical practice. In this study, a high-efficiency expression system was established to purify recombinant HE4. We obtained high purity HE4 in 400 mg quantity from 1 L culture supernatant of HEK293F cells. CCK-8 and cell cycle assays indicated that the purified recombinant HE4 protein could promote SKOV3 cell cycle and proliferation at the concentration of 0.1 mg/L. Furthermore, an anti-HE4 high-affinity monoclonal antibody 9C3 (ka = 8.1 × 106 1/MS, kd = 4.4 × 10-5 1/S, KD = 5.5 × 10-12 M) was prepared using hybridoma technique and analyzed by surface plasmon resonance technology using this HE4 protein. Differential Scanning calorimeter (DSC) analysis showed that 9C3 had a commendable thermal stability with the Tm value of 73 °C. Analyses of western blot, immunohistochemistry and immunofluorescence showed that the 9C3 was highly specific to HE4 in human cancer cells and tissues. In conclusion, our study designed a method to prepare human recombinant HE4 with high yield and generated a high-affinity anti-HE4 monoclonal antibody that might have potential for basic research and clinical application.

[Differentially expressed proteins of severe acute pancreatitis intervened by Qingyi granule].

OBJECTIVE: To observe the effects of Qingyi Granule (QYG) on the changes of total protein expressions in the pancreatic tissue of rats with severe acute pancreatitis (SAP) induced by sodium taurocholate (STC). METHODS: SAP was induced by retrograded injecting 5% STC from the gut-pancreatic duct in 36 Sprague-Dawley (SD)rats. Then they were randomly divided into the SAP group and the QYG treatment group (abbreviated as the QYG group), 18 in each group. After successful modeling, rats in the QYG group were administered with QYG water solution (W: W = 1:1) once with an interval of 12 h (1 mL/100 g), while rats in the SAP group were administered with normal saline. The medication was performed four times. The total proteins were extracted from the pancreatic tissue of all rats to perform two-dimensional electrophoresis, fluorescent staining, and atlas analysis. The protein dots with differential expressions more than four times between each other in 48 h gel pictures were chosen and used for MALDI-TOF/TOF mass chromatographic analysis and biological information analysis. RESULTS: The 5% STC induced SAP model rats had typical pathological changes in the pancreatic tissue. The proteomics changes of the pancreatic tissue were analyzed by gel image manipulation software. Twenty two disparate points were detected between two groups at 48 h, 5 points of the protein were up-regulated and 17 points were down-regulated of the total after QYG intervention. Nine protein spots expressed differently more than 4 times and stably at 48 h, 7 kinds of proteins have been identified by mass chromatographic analysis and Data Base Retrieval, and they were Serpinb1a 39 kDa protein, Serpinb1a 43 kDa protein, Prdx4 Prx IV, Clps, gamma-actin (Actg1), Eprs and Hadhsc. Those proteins were involved in signal transmit during the process of SAP pancreas--pathological injury analyzed from their functions. CONCLUSIONS: Proteomics can well reflect the effects of QYG on differential expression proteins in the pancreatic tissue of rats with SAP. Studying differential expression proteins may provide a new theoretical basis and molecule target for QYG treating SAP.

Tuning the optical absorption performance of MoS2 monolayers with compressive strain.

Strain engineering has been extensively applied as a promising strategy in the regulation of physical and chemical properties of two-dimensional (2D) materials, which remarkably broadens their application prospects in flexible electronics and chip manufacturing. However, the difficulty in fixing a flexible substrate under compression and the challenge in adjusting the focal distance have hindered the in-depth investigation of compressive strain. Here, we fabricated a home-made strain loading device and proposed a compressive strain measurement method, via which the strain-dependent optical absorption properties of MoS2 monolayers under compression has been studied. According to the measured optical absorption spectra, the first blueshift and then redshift trend under compression was obviously observed. The reliability of the experimentally observed trend in peak position shift was theoretically verified by density functional theory calculation. Our work offers a feasible way to characterize optical properties of 2D materials under compressive strain and expands the space for the development of next-generation micro/nano-scale optoelectronic devices.

Identification of long non­coding RNA­mediated transcriptional dysregulation triplets reveals global patterns and prognostic biomarkers for ER+/PR+, HER2­ and triple negative breast cancer.

Breast cancer (BRCA) is the most common type of cancer in adult females. Estrogen receptor (ER)+/progesterone receptor (PR)+, human epidermal­growth factor receptor 2 (HER2)­ BRCA and triple­negative breast cancer (TNBC) are two important subtypes of this disease. Long non­coding RNA (lncRNA)­mediated transcriptional dysregulation triplets (lncTDTs) may contribute to the development of cancer; however, the precise functional roles of lncTDTs in ER+/PR+, HER2­ BRCA and TNBC require further investigation. In the present study, an integrated and computational approach was conducted to identify lncTDTs based on transcription factor (TF), gene, lncRNA expression profiles and experimentally verified TF­gene interactions. The regulatory patterns of these lncTDTs are complex and differed in ER+/PR+, HER2­ BRCA and TNBC. Of note, five common lncTDTs were reported for these BRCA subtypes. Functional analysis revealed lncTDTs to be enriched in the PI3K/AKT signaling pathway within the two BRCA subtypes. Additionally, certain lncTDTs were associated with survival and may be considered candidate prognostic biomarkers for BRCA subtypes. Collectively, the results of the present study provide novel insight into the functions and mechanisms of lncRNAs in ER+/PR+, HER2­ BRCA and TNBC, and may aid the development of targeted treatments against certain subtypes of BRCA.