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The use of high alkaline medium is a feasible way to provide carbon source and prevent biological contamination for the outdoor cultivation of alkaliphilic microalgae and cyanobacteria. A novel cyanobacterial strain was isolated from the open pond of a marine green alga (Picochlorum sp. SCSIO-45015, Sanya, Hainan) and identified as Cyanobacterium sp. SCSIO-45682. The effects of initial sodium bicarbonate (NaHCO3) concentrations on the growth and biochemical composition of Cyanobacterium sp. SCSIO-45682 were investigated. The results demonstrated that Cyanobacterium sp. SCSIO-45682 had good adaptation to 16.8 g/L NaHCO3 (the same concentration of NaHCO3 used in Zarrouk medium for Spirulina). Moreover, the yields of biomass, polysaccharide, chlorophyll a (chl a), and phycocyanin increased under high NaHCO3 concentrations. The maximum final biomass concentration of 2.5 g/L was observed at 8.4 g/L NaHCO3, while the highest intracellular total saccharide content of 49.2% of dry weight (DW) and exopolysaccharide (EPS) concentration of 93 mg/L were achieved at the NaHCO3 concentration of 16.8 g/L. The crude protein content declined under high NaHCO3 concentrations, which provide a possible explanation for the accumulation of polysaccharide. This study shows a good potential of alkaliphilic Cyanobacterium sp. SCSIO-45682 as a polysaccharide feedstock.

A mild, efficient, and transition-metal-free catalytic strategy is developed to construct thioesters via selective N–C bond cleavage of Boc2-activated primary amides. This strategy is successfully carried out with stoichiometric Na2CO3 as the base and provides the corresponding products in moderate to excellent yields.

CO2 reduction is a very attractive research field in environmental, material, and chemical science in light of the energy crisis and the greenhouse effect. In this study, Bi2WO6/BiOCl heterojunctions were fabricated onto the F-SnO2 transparent conductive glass in situ by a hydrothermal method. These new photocathodes, named BCW-X, were characterized by such methods as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscope, and UV-vis spectra. Their morphology is a good 2D layered/3D flower structure. The exposed crystal plane of BiOCl was changed from (1 0 1) of the pristine form to (1 1 2) in the heterojunction. The photoelectrocatalytic reduction of CO2 was carried out in BCW-X|KHCO3|BiVO4 under irradiation by an Xe lamp and external voltage from a Si solar cell (−0.6 to −1.1 V). A PEC cell of BCW-6|KHCO3|BiVO4 produces ethanol at a rate of 11.4 μM h−1 cm−2 (600 μmol h−1 g−1) with 80.0% selectivity under −1.0 V. The apparent quantum efficiency is up to 0.63%, about three times that of composite BiOCl–Bi2WO6 as photocathode. These phenomena can be attributed to the better photogenic electron–hole separation and high charge separation efficiency of heterojunctions.

Pseudorabies virus (PRV) infection can elicit nervous system disorders. Curcumin has been reported to have neuroprotective effects. However, whether curcumin can protect neurons against PRV infection and the underlying mechanisms remain unclear. In the present study, for the first time, the protective effects of curcumin against PRV-induced oxidative stress, apoptosis, and mitochondrial dysfunction in rat hippocampal neurons and the brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) pathway were investigated. Results indicated that PRV with a titer of 3.06 × 106 TCID50 (50% tissue culture infective dose) induced oxidative damage of hippocampal neurons 2 h post-infection and that 10 μM curcumin improved the viability of PRV-infected hippocampal neurons. Blocking the BDNF/TrkB pathway reversed the neuroprotective effects of curcumin, which were imparted by decreasing the PRV-induced upregulation of nitric oxide synthase expression, repressing the PRV-activated mitochondrial apoptotic pathway, and mitochondrial dysfunction. To conclude, curcumin exhibited a neuroprotective role against PRV infection by upregulating the BDNF/TrkB pathway. This study provides insight into the anti-PRV neuroprotective application of curcumin and the underlying mechanism in the prophylaxis and treatment of neurological disorders caused by PRV infection.

To improve the yields of specific value-added compounds from Arthrospira platensis, one generally accepted method is to obtain mutant strains with increased target component content and growth rate. In the present study, mutation breeding of seawater A. platensis SCSIO-44012 (the wild type strain, hereafter WT) through space-flight carriage by Shijian-10 satellite was carried out. After returning to earth, 183 single filaments were picked out, 43 of which survived. During the following consecutive subcultures, one out of the 43 mutant strains, named A. platensis SCSIO-44012-H11 (hereafter H11), showed stable advantages in high levels of polysaccharides production. The biomass yield, total sugar content, and total sugar productivity of H11 remained stable at 0.88 g L−1, 24.82% DW, and 21.78 mg L−1 d−1, respectively, from the 10th to 35th generations of subculture, which were 8.6%, 62.26%, and 73.68%, respectively, higher than that of WT. The biochemical compositions of polysaccharide extracts (PSE) from H11 and WT also exhibited significant differences. The total sugar content of H11 PSE reached 55.37%, 2.49 times as much as that of WT PSE. The PSE from H11 was enriched in the component cutting off 100 kDa, accounting for 89.32% of the total polysaccharides, whereas WT PSE was mainly composed of the component with a molecular weight between 10 kDa and 50 kDa. The predominant monosaccharide of H11 PSE was glucose, followed by rhamnose, which accounted for 84.53% and 8.13% of the total monosaccharides, respectively. By comparison, glucose and rhamnose occupied 27.33% and 35.41%, respectively, in PSE from WT. Furthermore, the PSE from H11 showed strong ferrous ion-chelating activity and moisture retention capacity. These results indicated the feasibility of H11 as a polysaccharides feedstock applied in cosmetics, nutraceuticals, and medicines.

Here, we present a dual amplification strategy based on a duplex-specific nuclease and a hybridization chain reaction, which has been designed for the highly sensitive detection of miRNAs. In the first step, a loop amplification strategy based on a duplex-specific nuclease was employed to obtain a large number of ssDNA reporters that then act as initiators to trigger the next amplification step. The second step involves a hybridization chain reaction based on two hairpin DNAs denoted as H1 and H2. Doxorubicin-CdTe quantum dots, which function as detecting indicators that intercalated into the hybridization chain reaction products, lead to significantly amplified electrochemiluminescence signal readout. This dual amplification strategy enabled the sensitive detection of let-7d from 10 aM to 10 nM with a detection limit of 10 aM, and offered an excellent capacity to discriminate between microRNA family members. This assay therefore offers great potential applications in biomedical research and early clinical diagnosis.

Ethnopharmacological relevance Terminalia catappa L. (West Indian-Almond) is a medicinal plant used in traditional medicine for the treatment of infectious diseases. Moreover, various organic extracts prepared from this plant have been reported to exhibit antiplasmodial activity. Aim of the study The need for new antimalarials is still an urgency driven by the alarmingly high burden of malaria in endemic regions, with multitude of people dying annually. We have previously identified an endophytic fungus Aspergillus niger 58 harboured by T. catappa as having promising specialized secondary metabolites against the malaria parasites. In the present study, we report the antiplasmodial activity-guided chromatographic isolation of some metabolites secreted by this endophytic fungus. Materials and methods The SYBR Green I-based fluorescence microtiter plate assay was used to monitor the growth of Plasmodium falciparum parasites in culture in the presence and absence of inhibitors and results were validated by microscopic analysis of Giemsa-stained culture smears. Giemsa-stain microscopy was also used to study the cell cycle stage-specific action of selected fractions. Results The results revealed that the multidimensional purification of the crude extract (IC50: 4.03 μg/mL) provided RPHPLC F17 (IC50: 0.09 μg/mL) and RPHPLC F18 (IC50: 0.1 μg/mL) with activity against P. falciparum 3D7 (Pf3D7) strain. Moreover, both fractions at IC99 (0.5 μg/mL) exhibited multi-stages action by targeting all the three stages of the life cycle of blood-stage Pf3D7. Two compounds, flavasperone (1) and aurasperone A (2) were isolated, of which aurasperone A exhibited good potency against Pf3D7 (IC50: 4.17 μM) and P. falciparum INDO (PfINDO) (IC50: 3.08 μM). Conclusion Our study adds credence to the notion that endophytic extracts are potential storehouses for potent specialized secondary metabolites that can be harnessed to fight the malaria parasite and reduce the burden of this disease worldwide. An endophyte that can be cultured in laboratory with ability to secrete promising metabolites of medicinal value holds the promise of conserving Nature from the threat of annihilation of flora for medicinal purposes.

Algal β-glucans have received attention in recent years, but little is understood for the pattern and molecular mechanism of β-glucans accumulation in Chlorella, a more economically feasible microalga. In the present study, P-limited conditions were found to substantially inhibit the microalgal growth, reduce the lipid and protein production but induce the accumulation of β-glucans and total carbohydrate of Chlorella sorokiniana SCSIO 46784 during the early phase of growth. Comparative transcriptomics analysis of the microalga for the specific time point under P-limited and P-replete conditions identified key genes involved in β-glucans metabolism and revealed the probable molecular mechanism of the β-glucans accumulation. The significant up- and down-regulation of genes encoding β-glucans synthesis- and degradation-related enzymes coincided with a rapid increase in β-glucans production. The reduced synthesis of certain sugars (starch, sucrose, UDP-L-rhamnose, and UDP-sulfoquinovose) might provide more carbon precursors for β-glucans biosynthesis. The suppression of lipids (fatty acid, triacylglycerol, sulfoquinovosyl diacylglycerol, and monogalactosyldiacylglycerol) synthesis presumably shunted carbon flux toward carbohydrates and β-glucans biosynthesis. In addition, the down-regulation of multiple genes related to carbon fixation (CO2 concentrating mechanism and Calvin cycle) and central carbon metabolism (pentose phosphate pathway, glycolysis/gluconeogenesis, and tricarboxylic acid cycle) might contribute to the inferior growth of C. sorokiniana SCSIO 46784 under P-limited conditions. To our knowledge, this is the first report to reveal the metabolic insights into β-glucans in Chlorella. This study provides not only the useful information for understanding the biosynthesis and accumulation of β-glucans but also potential gene targets for genetic modification to improve the production of β-glucans in Chlorella.

The development of high-performance catalysts for CO2 reduction to hydrocarbons is of great importance for addressing the energy crisis issue. In this work, the Cu@porphyrin-COFs nanorods materials were first designed and synthesized by solvothermal method followed by the electrodeposition of Cu nanowires to the free-base porphyrin-COFs on the carbon fibers. The structure of the free-base porphyrin-COFs were well characterized experimentally and simulatively calculated by DFT method. The Cu@porphyrin-COFs nanorods show high catalytic activity for CO2 reduction under photoelectrocatalytic (PEC) conditions, giving C1–C3 chemicals such as methanol (CH3OH), ethanol (CH3CH2OH), ethane-1,1-diol (CH3CH(OH)2) and acetone (CH3COCH3) with an extremely apparent Faradaic efficiency (AFE) of total carbon-based products of 452.75% due to the efficient adsorption of protons onto the surfaces of Cu crystals and excellent absorption of solar light. The 13CO2 labeling experiments verified that the carbon-based products are derived from CO2. On the other hand, combining with simulation, we show that the hydroxyl groups in free-base porphyrins COFs play a vital role in photoelectrocatalytic reduction of CO2.

Two new 2-benzylpyridin-4-one containing metabolites, aspernigrins C (3) and D (4), together with six known compounds (1, 2, and 5-8), were isolated from the marine-derived fungus Aspergillus niger SCSIO Jcsw6F30. The structures of the new compounds were determined by NMR, MS, and optical rotation analyses. All the isolated compounds were evaluated for their inhibitory activities against infection with HIV-1 SF162 in TZM-bl cells. Malformin C (5) showed the strongest anti-HIV-1 activity with IC50 of 1.4±0.06μM (selectivity index, 11.4), meanwhile aspernigrin C (3) also exhibited potent activity with IC50 of 4.7±0.4μM (selectivity index, 7.5).

Chitosan-based active films were developed by incorporation of carvacrol (10 g/L), pomegranate peel extract (PPE, 10 g/L) and carvacrol + PPE (10 g/L of each) and their physical, antioxidant and antimicrobial properties were investigated. Incorporation of carvacrol and carvacrol + PPE into the films significantly decreased the water vapor permeability, tensile strength and percentage of elongation at break. Incorporation of carvacrol, PPE and carvacrol + PPE into the films decreased the transparency, but significantly increased the total phenol content and antioxidant activity. All the films, with the exception of PPE-incorporated film, exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus. In addition, the antibacterial activity against Staphylococcus aureus of the film incorporated with carvacrol + PPE was moderately higher than that incorporated with carvacrol or PPE alone, suggesting a synergistic action between carvacrol and PPE.

Chemical exfoliation method was applied to transform bulky assemblies of Au(I)–3-mercaptopropionate (MPA) coordination polymer (CP) to nanosheets and nanostrings using sodium citrate as an exfoliator. The exfoliation process and the structural characteristics of the Au(I)–MPA nanosheets and nanostrings were fully investigated by transmission electron microscopy, atomic force microscopy, UV–vis absorption spectroscopy, X-ray photoelectron spectroscopy and so on. As the structural rigidity and stability of the obtained Au(I)–MPA nanosheets, they are ideal precursors for fabrication of water soluble gold nanoparticle assemblies through progressive pyrolysis. This work provides a significant strategy toward the morphology regulation of CP nanostructures and will inspire further development of this research area.

Spiropyran thin film with capability of light-triggered molecular level self-healing has been successfully designed and fabricated by Langmuir-Blodgett technology. Various remarkable properties of thin film shrinkage or height increase or self-healing nano-defect recovery under different fabrication conditions have been observed. In addition, further evidence of the self-healing, which resulted from the movement of spiropyran molecules (such as "standing" "lie-down" and "tip-toes" etc.) on the substrate, has also been observed from the reversible contact angle change of the thin film.

Aspernigrin C (Ia) and D (Ib) are isolated as new compounds together with six known compounds from the marine-derived fungus Aspergillus niger SCSIO Jcsw6F30.

We report a simple method for the fabrication of biomimetic antireflective hierarchical arrays based on the combination of self-assembled polymer spheres and nanoimprint lithography (NIL). The hierarchical structures are fabricated by creating nanopillars on the microscale round protrusion arrays, which are similar to natural mosquito eyes consisting of combined micro- and nanostructures. The hierarchical arrays dramatically suppress the surface reflection from visible to near-infrared regions with an angle of incidence of up to 70°.

Therefore,oneoftheimportantchallengesinfabricatingmetallicmicrostructures is to find an easy, repeatable, and controllablemethod to meet the increasing demands in optoelectronics andplasmonics.In this communication, we report a new template-assistedelectrochemical approach to fabricate arrays of metallic nano-wires. Unlike conventional template-assisted growth, where thegenerated wires are confined by the size of template, in ourcase the width of the metallic wires can be tuned by changing thecontrol parameters of electrodeposition. By imprinting polymerstripes ona silicon surface, the concave corner of polymerstripesandsiliconsubstrateprovidesapreferentialnucleationsitefortheformation of metal nanowires. The width of wires can be tunedfrom 25nm to a few hundred nanometers. Further, wedemonstrate that this method can be applied for fabricatingmore complicated structures rather than straight lines only.In our experiments, the metallic nanowires are electrodepo-sited with the help of polymer stripes embossed on siliconsurfaces. To form the patterned substrate, a thin film ofpoly(methylmethacrylate) (PMMA) (mr-I 7030E M

A simple approach to wafer-scale self-cleaning antireflective hierarchical silicon structures is demonstrated. By employing the KOH etching and silver catalytic etching, pyramidal hierarchical structures were generated on the crystalline silicon wafer, which exhibit strong antireflection and superhydrophobic properties after fluorination. Furthermore, a flexible superhydrophobic substrate was fabricated by transferring the hierarchical Si structure to the NOA 63 film with UV-assisted imprint lithography. This method is of potential application in optical, optoelectronic, and wettability control devices.

In this work, we present a method for fabricating high-resolution metal arrays based on the topography-mediated electrochemical deposition (ECD) process. By this approach, silver arrays of 200nm feature size can be obtained with the mediation of microscale patterns on silicon wafer. It should be possible to extend this method to other materials and substrates, which may have applications in sensors, optical and optoelectronic devices.

We present a simple solvent-assisted soft lithography method to fabricate titania (TiO(2)) patterns. The dimensions of the TiO(2) features can be controlled by adjusting the concentration of the solution, the solvent evaporation duration, and temperature. This method may provide a facile route for fabricating large area patterns of metal oxide.

The gene cloning, purification, properties, kinetics, and antifungal activity of chitinase from marine Streptomyces sp. DA11 associated with South China sponge Craniella australiensis were investigated. Alignment analysis of the amino acid sequence deduced from the cloned conserved 451 bp DNA sequence shows the chitinase belongs to ChiC type with 80% similarity to chitinase C precursor from Streptomyces peucetius. Through purification by 80% ammonium sulfate, affinity binding to chitin and diethylaminoethyl-cellulose anion-exchange chromatography, 6.15-fold total purification with a specific activity of 2.95 Umg(-1) was achieved. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed a molecular weight of approximately 34 kDa and antifungal activities were observed against Aspergillus niger and Candida albicans. The optimal pH, temperature, and salinity for chitinase activity were 8.0, 50 degrees C, and 45 g per thousand psu, respectively, which may contribute to special application of this marine microbe-derived chitinase compared with terrestrial chitinases. The chitinase activity was increased by Mn(2+), Cu(2+), and Mg(2+), while strongly inhibited by Fe(2+) and Ba(2+). Meanwhile, SDS, ethyleneglycoltetraacetic acid, urea, and ethylenediaminetetraacetic acid were found to have significantly inhibitory effect on chitinase activity. With colloidal chitin as substrates instead of powder chitin, higher V (max) (0.82 mg product/min.mg protein) and lower K (m) (0.019 mg/ml) values were achieved. The sponge's microbial symbiont with chitinase activity may contribute to chitin degradation and antifungal defense. To our knowledge, it was the first time to study sponge-associated microbial chitinase.

A bio-inspired antireflective hetero-nanojunction structure has been fabricated by the hydrothermal growth of ZnO nanorods on silicon micro-pyramids. It has been shown that this structure suppresses light reflection more effectively resulting in a high photocurrent response and good charge separation simultaneously. The strategy provides a means to enhance solar energy conversion.