Microanalysis Characterization and Immunomodulatory Effect for Selenium-Enriched Polysaccharide from Morchella esculenta (L.) Pers.

Morchella esculenta (L.) Pers., referred to as Morel, is a medicinal and edible homologous fungus, which contains many bioactive substances. In Morel, polysaccharides are the most abundant and have various bioactivities. In the present work, two novel polysaccharides, Se-MPS and MPS, were prepared and purified from selenium-enriched (Se-enriched) and common Morel mycelia, respectively, and their structural and immunomodulatory properties were evaluated. The results show that Se-enriched treatment significantly changed the polysaccharides' chemical composition, molecular weight, and sugar chain configuration. In addition, the Se-enriched treatment also improved the polysaccharides' fragmentation and thermal stability. Importantly, Se-enriched Morel polysaccharide (Se-MPS) could significantly enhance phagocytosis of RAW 264.7 macrophage cells and, remarkably, activate their immune response via activating the TLR4-TRAF6-MAPKs-NF-κB cascade signaling pathway, finally exerting an immunomodulatory function. Based on these findings, selenium-enriched Morel polysaccharide appears to have more potential for development and utilization in functional foods or medicines than ordinary Morel polysaccharide.

Design, green synthesis, antioxidant activity screening, and evaluation of protective effect on cerebral ischemia reperfusion injury of novel monoenone monocarbonyl curcumin analogs.

Antioxidants with high efficacy and low toxicity have the potential to treat cerebral ischemia reperfusion injury (CIRI). Dienone monocarbonyl curcumin analogs (DMCA) capable of overcoming the instability and pharmacokinetic defects of curcumin possess notable antioxidant activity but are found to be significantly toxic. In this study, a novel skeleton of the monoenone monocarbonyl curcumin analogue sAc possessing reduced toxicity and improved stability was designed on the basis of the DMCA skeleton. Moreover, 32 sAc analogs were obtained by applying a green, simple, and economical synthetic method. Multiple sAc analogs with an antioxidant protective effect in PC12 cells were screened using an H2O2-induced oxidative stress damage model, and quantitative evaluation of structure-activity relationship (QSAR) model with regression coefficient of R2 = 0.918921 was built through random forest algorithm (RF). Among these compounds, the optimally active compound sAc15 elicited a potent protective effect on cell growth of PC12 cells by effectively eliminating ROS generation in response to oxidative stress injury by activating the Nrf2/HO-1 antioxidant signaling pathway. In addition, sAc15 exhibited good protection against CIRI in the mice middle cerebral artery occlusion (MCAO) model. In this paper, we provide a novel class of antioxidants and a potential compound for stroke treatment.

Intratracheally instillated diesel PM2.5 significantly altered the structure and composition of indigenous murine gut microbiota.

A diverse and large community of gut microbiota reside in the intestinal tract of various organisms and play important roles in metabolism and immune homeostasis of its host. The disorders of microbiota-host interaction have been closely associated with numerous chronic inflammatory and metabolic diseases, including inflammatory bowel disease and type 2 diabetes. The accumulating evidence has shown that fine particulate matter (PM2.5) exposure contributes to the diabetes, atherosclerosis and inflammatory bowel diseases; however, few studies have explored the impact of inhaled diesel PM2.5 on gut microbiota in vivo. In this study, C57BL/6J mice were exposed to diesel PM2.5 for 14 days via intratracheal instillation, and colon tissues and feces were harvested for microbiota analysis. Using high-throughput sequencing technology, we observed that intratracheally instillated diesel PM2.5 significantly altered the gut microbiota diversity and community. At the phylum and genus levels, principal coordinate analysis (PCoA) and principal component analysis (PCA) indicated pronounced segregation of microbiota compositions, which were further confirmed by ß diversity analysis. As the most affected phylum, Bacteroidetes was greatly diminished by diesel PM2.5. On the genus level, Escherichia, Parabacteroides, Akkermansia, and Oscillibacter were significantly elevated by diesel PM2.5 exposure. Our findings provided clear evidence that exposure to diesel PM2.5 via intratracheal instillation deteriorated the gastrointestinal (GI) tract and significantly altered the structure and composition of gut microbiota, which might subsequently contribute to the developmental abnormalities of inflammation, immunity and metabolism.

Oridonin interrupts cellular bioenergetics to suppress glioma cell growth by down-regulating PCK2.

We aim to evaluate the tumor metabolic suppressive activity of Oridonin (extract of Rabdosia rubescens) in glioma and elucidate its potential mechanism. Effects of Oridonin on U251/U87 cells were determined by CCK8, RTCA, colony formation, flow cytometry, wound healing, and Transwell assay. Xenograft tumor model to evaluate the effect of Oridonin on glioma cells in vivo. Cellular bioenergetics were measured by Seahorse. RNA-seq was performed to screen potential biological pathways in Oridonin treated cells. Bioinformatics analysis of PCK2 in glioma was performed based on TCGA/CGGA. Endogenous PCK2 was knocked-down by lentivirus packaged shRNA. We found Oridonin significantly inhibited cell growth in U251/U87 in vitro and in vivo. Both oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were decreased in Oridonin-treated U251/U87 cells. Oridonin treatment led to PCK2 down-regulation. Additionally, PCK2 was up-regulated in higher grade glioma and correlated with poor outcomes. Furthermore, PCK2 depletion significantly inhibited cell growth and decreased OCR/ECAR in U251/U87 which coincided with the effects of Oridonin. Therefore, we evaluated the potent anti-tumor property of Oridonin in glioma. Importantly, we demonstrated that PCK2 might be a novel target of Oridonin on glioma by inducing energy crisis and increasing oxidative stress.

New Measures for the Coronavirus Disease 2019 Response: A Lesson From the Wenzhou Experience.

As the outbreak of coronavirus disease 2019 (COVID-19) has spread globally, determining how to prevent the spread is of paramount importance. We reported the effectiveness of different responses of 4 affected cities in preventing the COVID-19 spread. We expect the Wenzhou anti-COVID-19 measures may provide information for cities around the world that are experiencing this epidemic.

Mapping coastal circulations using moving vehicle acoustic tomography.

With the increased availability of highly maneuverable unmanned surface/underwater vehicles, abundant ocean data can now be collected. This study uses tomographic techniques to extend the survey area covered by moving vehicles. An acoustic reciprocal transmission experiment was conducted using three tomographic sensors installed on an autonomous underwater vehicle, a fishing ship, and a buoy. The distributed sensing method is applied for currents estimation. The estimated currents near the ship show consistent results with the direct measurements. In particular, an anticyclonic circulation was revealed. Further, a general least-squares method is employed to improve the estimate of this vortical structure.

Correction: Wang, Y.T., et al. Selenium Nanoparticle Synthesized by Proteus mirabilis YC801: An Efficacious Pathway for Selenite Biotransformation and Detoxification. Int. J. Mol. Sci. 2018, 19, 3809.

The authors wish to make the following corrections to this paper [...].

Correction: Wang, Y.T., et al. Selenite Reduction and the Biogenesis of Selenium Nanoparticles by Alcaligenes faecalis Se03 Isolated from the Gut of Monochamus alternatus (Coleoptera: Cerambycidae). Int. J. Mol. Sci. 2018, 19, 2799.

The authors wish to make the following corrections to this paper [...].

Polyacrylic acid-coated nanoparticles loaded with recombinant tissue plasminogen activator for the treatment of mice with ischemic stroke.

Nanoparticle-based thrombolysis is a potential new treatment for stroke. The aim of this study was to investigate the efficacy of targeted thrombolysis using recombinant tissue plasminogen activator (rtPA). The rtPA was covalently bound to magnetic nanoparticles (MNP) and maintained at the target site using an external magnet. Polyacrylic acid (PAA)-coated MNP were synthesized and rtPA was then bound to the resultant PAA-MNP via carbodiimide-mediated amide bonds. For the in vitro tests, blood clots were formed in plastic centrifuge tubes with anti-coagulated plasma, thrombin and calcium chloride. For the in vivo tests, mice with ferric chloride-induced distal middle cerebral artery occlusion were treated with phosphate-buffered saline (PBS), MNP, rtPA, or MNP-rtPA (n = 6 mice per group). The binding efficacy was 80.7 ± 1.5 µg rtPA bound to 1 mg PAA-MNP. In the in vitro tests, the mean lysis percentage dramatically increased from 1.28% in the MNP group without rotation to 77.40% in the rtPA + MNP group with rotating magnetic field. The lysis efficiency of MNP-rtPA was 27.3 ± 1.3%, and it increased to 42.8 ± 2.8% with magnetic field rotation. The mean sizes of the infarct areas of the PBS, MNP, rtPA, and MNP-rtPA mouse groups were 20.09 ± 6.07, 18.28 ± 2.69, 8.65 ± 3.63 and 4.40 ± 2.46 mm3, respectively. Thus, targeted MNP-rtPA accelerated thrombolysis and reduced the infarct area in a mouse model of cerebral embolism. This approach may serve as a feasible and effective treatment for embolic cerebral ischemia.

Overexpression of the Stress-Inducible SsMAX2 Promotes Drought and Salt Resistance via the Regulation of Redox Homeostasis in Arabidopsis.

Recent studies have demonstrated that strigolactones (SLs) also participate in the regulation of stress adaptation; however, the regulatory mechanism remains elusive. In this study, the homolog of More Axillary Branches 2, which encodes a key component in SL signaling, in the perennial oil plant Sapium sebiferum was identified and functionally characterized in Arabidopsis. The results showed that the expression of SsMAX2 in S. sebiferum seedlings was stress-responsive, and SsMAX2 overexpression (OE) in Arabidopsis significantly promoted resistance to drought, osmotic, and salt stresses. Moreover, SsMAX2 OE lines exhibited decreased chlorophyll degradation, increased soluble sugar and proline accumulation, and lower water loss ratio in response to the stresses. Importantly, anthocyanin biosynthesis and the activities of several antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX), were enhanced in the SsMAX2 OE lines, which further led to a significant reduction in hydrogen peroxide levels. Additionally, the SsMAX2 OE lines exhibited higher expression level of several abscisic acid (ABA) biosynthesis genes, suggesting potential interactions between SL and ABA in the regulation of stress adaptation. Overall, we provide physiological and biochemical evidence demonstrating the pivotal role of SsMAX2 in the regulation of osmotic, drought, and salt stress resistance and show that MAX2 can be a genetic target to improve stress tolerance.

Comparative transcriptome analysis reveals the regulatory networks of cytokinin in promoting the floral feminization in the oil plant Sapium sebiferum.

BACKGROUND: Sapium sebiferum, whose seeds contain high level of fatty acids, has been considered as one of the most important oil plants. However, the high male to female flower ratio limited the seed yield improvement and its industrial potentials. Thus, the study of the sex determination in S. sebiferum is of significant importance in increasing the seed yield. RESULTS: In this study, we demonstrated that in S. sebiferum, cytokinin (CK) had strong feminization effects on the floral development. Exogenous application with 6-benzylaminopurine (6-BA) or thidiazuron (TDZ) significantly induced the development of female flowers and increased the fruit number. Interestingly, the feminization effects of cytokinin were also detected on the androecious genotype of S. sebiferum which only produce male flowers. To further investigate the mechanism underlying the role of cytokinin in the flower development and sex differentiation, we performed the comparative transcriptome analysis of the floral buds of the androecious plants subjected to 6-BA. The results showed that there were separately 129, 352 and 642 genes differentially expressed at 6 h, 12 h and 24 h after 6-BA treatment. Functional analysis of the differentially expressed genes (DEGs) showed that many genes are related to the hormonal biosynthesis and signaling, nutrients translocation and cell cycle. Moreover, there were twenty one flowering-related genes identified to be differentially regulated by 6-BA treatment. Specifically, the gynoecium development-related genes SPATULA (SPT), KANADI 2 (KAN2), JAGGED (JAG) and Cytochrome P450 78A9 (CYP79A9) were significantly up-regulated, whereas the expression of PISTILLATA (PI), TATA Box Associated Factor II 59 (TAFII59) and MYB Domain Protein 108 (MYB108) that were important for male organ development was down-regulated in response to 6-BA treatment, demonstrating that cytokinin could directly target the floral organ identity genes to regulate the flower sex. CONCLUSIONS: Our work demonstrated that cytokinin is a potential regulator in female flower development in S. sebiferum. The transcriptome analysis of the floral sex transition from androecious to monoecious in response to cytokinin treatment on the androecious S. sebiferum provided valuable information related to the mechanism of sex determination in the perennial woody plants.

Selenium Nanoparticle Synthesized by Proteus mirabilis YC801: An Efficacious Pathway for Selenite Biotransformation and Detoxification.

Selenite is extremely biotoxic, and as a result of this, exploitation of microorganisms able to reduce selenite to non-toxic elemental selenium (Se°) has attracted great interest. In this study, a bacterial strain exhibiting extreme tolerance to selenite (up to 100 mM) was isolated from the gut of adult Monochamus alternatus and identified as Proteus mirabilis YC801. This strain demonstrated efficient transformation of selenite into red selenium nanoparticles (SeNPs) by reducing nearly 100% of 1.0 and 5.0 mM selenite within 42 and 48 h, respectively. Electron microscopy and energy dispersive X-ray analysis demonstrated that the SeNPs were spherical and primarily localized extracellularly, with an average hydrodynamic diameter of 178.3 ± 11.5 nm. In vitro selenite reduction activity assays and real-time PCR indicated that thioredoxin reductase and similar proteins present in the cytoplasm were likely to be involved in selenite reduction, and that NADPH or NADH served as electron donors. Finally, Fourier-transform infrared spectral analysis confirmed the presence of protein and lipid residues on the surfaces of SeNPs. This is the first report on the capability of P. mirabilis to reduce selenite to SeNPs. P. mirabilis YC801 might provide an eco-friendly approach to bioremediate selenium-contaminated soil/water, as well as a bacterial catalyst for the biogenesis of SeNPs.

Selenite Reduction and the Biogenesis of Selenium Nanoparticles by Alcaligenesfaecalis Se03 Isolated from the Gut of Monochamus alternatus (Coleoptera: Cerambycidae).

In this study, a bacterial strain exhibiting high selenite (Na2SeO3) tolerance and reduction capacity was isolated from the gut of Monochamus alternatus larvae and identified as Alcaligenes faecalis Se03. The isolate exhibited extreme tolerance to selenite (up to 120 mM) when grown aerobically. In the liquid culture medium, it was capable of reducing nearly 100% of 1.0 and 5.0 mM Na2SeO3 within 24 and 42 h, respectively, leading to the formation of selenium nanoparticles (SeNPs). Electron microscopy and energy dispersive X-ray analysis demonstrated that A. faecalis Se03 produced spherical electron-dense SeNPs with an average hydrodynamic diameter of 273.8 ± 16.9 nm, localized mainly in the extracellular space. In vitro selenite reduction activity and real-time PCR indicated that proteins such as sulfite reductase and thioredoxin reductase present in the cytoplasm were likely to be involved in selenite reduction and the SeNPs synthesis process in the presence of NADPH or NADH as electron donors. Finally, using Fourier-transform infrared spectrometry, protein and lipid residues were detected on the surface of the biogenic SeNPs. Based on these observations, A. faecalis Se03 has the potential to be an eco-friendly candidate for the bioremediation of selenium-contaminated soil/water and a bacterial catalyst for the biogenesis of SeNPs.

Exogenous Melatonin Confers Cadmium Tolerance by Counterbalancing the Hydrogen Peroxide Homeostasis in Wheat Seedlings.

Melatonin has emerged as a research highlight regarding its important role in regulating plant growth and the adaptation to the environmental stresses. In this study, we investigated how melatonin prevented the cadmium toxicity to wheat seedlings. The results demonstrated that cadmium induced the expression of melatonin biosynthesis-related genes and cause a significant increase of endogenous melatonin level. Melatonin treatment drastically alleviated the cadmium toxicity, resulting in increased plant height, biomass accumulation, and root growth. Cadmium and senescence treatment significantly increased the endogenous level of hydrogen peroxide, which was strictly counterbalanced by melatonin. Furthermore, melatonin treatment caused a significant increase of GSH (reduced glutathione) content and the GSH/GSSG (oxidized glutathione) ratio. The activities of two key antioxidant enzymes, ascorbate peroxidase (APX) and superoxide dismutase (SOD), but not catalase (CAT) and peroxidase (POD), were specifically improved by melatonin. Additionally, melatonin not only promoted the primary root growth, but also drastically enhanced the capacity of the seedling roots to degrade the exogenous hydrogen peroxide. These results suggested that melatonin played a key role in maintaining the hydrogen peroxide homeostasis, via regulation of the antioxidant systems. Conclusively, this study revealed a crucial protective role of melatonin in the regulation of cadmium resistance in wheat.

Comparative Evaluation of Integrated Waste Heat Utilization Systems for Coal-Fired Power Plants Based on In-Depth Boiler-Turbine Integration and Organic Rankine Cycle.

To maximize the system-level heat integration, three retrofit concepts of waste heat recovery via organic Rankine cycle (ORC), in-depth boiler-turbine integration, and coupling of both are proposed, analyzed and comprehensively compared in terms of thermodynamic and economic performances. For thermodynamic analysis, exergy analysis is employed with grand composite curves illustrated to identify how the systems are fundamentally and quantitatively improved, and to highlight key processes for system improvement. For economic analysis, annual revenue and investment payback period are calculated based on the estimation of capital investment of each component to identify the economic feasibility and competitiveness of each retrofit concept proposed. The results show that the in-depth boiler-turbine integration achieves a better temperature match of heat flows involved for different fluids and multi-stage air preheating, thus a significant improvement of power output (23.99 MW), which is much larger than that of the system with only ORC (6.49 MW). This is mainly due to the limitation of the ultra-low temperature (from 135 to 75 °C) heat available from the flue gas for ORC. The thermodynamic improvement is mostly contributed by the reduction of exergy destruction within the boiler subsystem, which is eventually converted to mechanical power; while the exergy destruction within the turbine system is almost not changed for the three concepts. The selection of ORC working fluids is performed to maximize the power output. Due to the low-grade heat source, the cycle with R11 offers the largest additional net power generation but is not significantly better than the other preselected working fluids. Economically, the in-depth boiler-turbine integration is the most economic completive solution with a payback period of only 0.78 year. The ORC concept is less attractive for a sole application due to a long payback time (2.26 years). However, by coupling both concepts, a net power output of 26.51 MW and a payback time of almost one year are achieved, which may promote the large-scale production and deployment of ORC with a cost reduction and competitiveness enhancement.

De novo assembly and characterization of the transcriptome of Morchella esculenta growth with selenium supplementation.

Although Morchella esculenta (L.) Pers. is an edible and nutritious mushroom with significant selenium (Se)-enriched potential, its biological response to selenium stimuli remains unclear. This study explored the effect of selenium on mushroom growth and the global gene expression profiles of M. esculenta. While 5 µg mL-1selenite treatment slightly promoted mycelia growth and mushroom yield, 10 µg mL-1significantly inhibited growth. Based on comparative transcriptome analysis, samples treated with 5 µg mL-1 and 10 µg mL-1 of Se contained 16,061 (452 upregulated and 15,609 downregulated) and 14,155 differentially expressed genes (DEGs; 800 upregulated and 13,355 downregulated), respectively. Moreover, DEGs were mainly enriched in the cell cycle, meiosis, aminoacyl-tRNA biosynthesis, spliceosome, protein processing in endoplasmic reticulum pathway, and mRNA surveillance pathway in both selenium-treated groups. Among these, MFS substrate transporter and aspartate aminotransferase genes potentially involved in Se metabolism and those linked to redox homeostasis were significantly upregulated, while genes involved in isoflavone biosynthesis and flavonoid metabolism were significantly downregulated. Gene expression levels increased alongside selenite treatment concentration, suggesting that high Se concentrations promoted M. esculenta detoxification. These results can be used to thoroughly explain the potential detoxification and Se enrichment processes in M. esculenta and edible fungi.

A Reliable Nonhuman Primate Model of Ischemic Stroke with Reproducible Infarct Size and Long-term Sensorimotor Deficits.

A nonhuman primate model of ischemic stroke is considered as an ideal preclinical model to replicate various aspects of human stroke because of their similarity to humans in genetics, neuroanatomy, physiology, and immunology. However, it remains challenging to produce a reliable and reproducible stroke model in nonhuman primates due to high mortality and variable outcomes. Here, we developed a focal cerebral ischemic model induced by topical application of 50% ferric chloride (FeCl3) onto the MCA-M1 segment through a cranial window in the cynomolgus monkeys. We found that FeCl3 rapidly produced a stable intraarterial thrombus that caused complete occlusion of the MCA, leading to the quick decrease of the regional cerebral blood flow in 10 min. A typical cortical infarct was detected 24 hours by magnetic resonance imaging (MRI) and was stable at least for 1 month after surgery. The sensorimotor deficit assessed by nonhuman primate stroke scale was observed at 1 day and up to 3 months after ischemic stroke. No spontaneous revascularization or autolysis of thrombus was observed, and vital signs were not affected. All operated cynomolgus monkeys survived. Our data suggested that FeCl3-induced stroke in nonhuman primates was a replicable and reliable model that is necessary for the correct prediction of the relevance of experimental therapeutic approaches in human beings.

Isolation and identification of cellulolytic bacteria from the gut of Holotrichia parallela larvae (Coleoptera: Scarabaeidae).

In this study, 207 strains of aerobic and facultatively anaerobic cellulolytic bacteria were isolated from the gut of Holotrichia parallela larvae. These bacterial isolates were assigned to 21 genotypes by amplified ribosomal DNA restriction analysis (ARDRA). A partial 16S rDNA sequence analysis and standard biochemical and physiological tests were used for the assignment of the 21 representative isolates. Our results show that the cellulolytic bacterial community is dominated by the Proteobacteria (70.05%), followed by the Actinobacteria (24.15%), the Firmicutes (4.35%), and the Bacteroidetes (1.45%). At the genus level, Gram-negative bacteria including Pseudomonas, Ochrobactrum, Rhizobium, Cellulosimicrobium, and Microbacterium were the predominant groups, but members of Bacillus, Dyadobacter, Siphonobacter, Paracoccus, Kaistia, Devosia, Labrys, Ensifer, Variovorax, Shinella, Citrobacter, and Stenotrophomonas were also found. Furthermore, our results suggest that a significant amount of bacterial diversity exists among the cellulolytic bacteria, and that Siphonobacter aquaeclarae, Cellulosimicrobium funkei, Paracoccus sulfuroxidans, Ochrobactrum cytisi, Ochrobactrum haematophilum, Kaistia adipata, Devosia riboflavina, Labrys neptuniae, Ensifer adhaerens, Shinella zoogloeoides, Citrobacter freundii, and Pseudomonas nitroreducens are reported to be cellulolytic for the first time in this study. Our results indicate that the scarab gut is an attractive source for the study of novel cellulolytic microorganisms and enzymes useful for cellulose degradation.

Novel mechanisms of selenite reduction in Bacillus subtilis 168：Confirmation of multiple-pathway mediated remediation based on transcriptome analysis.

Selenite biotransformation by microorganisms is an effective detoxification and assimilation process. Bacillus subtilis is a probiotic bacterium that can reduce Se(IV) to SeNPs under aerobic conditions. However, current knowledge on the molecular mechanisms of selenite reduction by B. subtilis remains limited. Here, the reduction of Se(IV) by probiotic bacterium Bacillus subtilis 168 was systematically analysed, and the molecular mechanisms of selenium nanoparticle (SeNPs) formation were characterised in detail. B. subtilis 168 reduced 5.0 mM selenite by nearly 40% in 24 h, and the produced SeNPs were spherical and localised intracellularly or extracellularly. FTIR (Fourier transform infrared) spectroscopy suggested the presence of proteins, lipids, and carbohydrates on the surface of the isolated SeNPs. Transcriptome data analysis revealed that the expression of genes associated with the proline metabolism, glutamate metabolism, and sulfite metabolism pathways was significantly up-regulated. Gene mutation and complementation revealed the ability of PutC, GabD, and CysJI to reduce selenite in vivo. In vitro experiments demonstrated that PutC, GabD, and CysJI could catalyse the reduction of Se(IV) under optimal conditions using NADPH as a cofactor. To the best of our knowledge, our study is the first to demonstrate the involvement of PutC and GabD in selenite reduction. Particularly, our findings demonstrated that the reduction of Se(IV) was mediated by multiple pathways both in vivo and in vitro. Our findings thus provide novel insights into the molecular mechanisms of Se(VI) reduction in aerobic bacteria.