Ultra-Thin RuIr Alloy as Durable Electrocatalyst for Seawater Hydrogen Evolution Reaction.

The development of efficient, high-performance catalysts for hydrogen evolution reaction (HER) remains a significant challenge, especially in seawater media. Here, RuIr alloy catalysts are prepared by the polyol reduction method. Compared with single-metal catalysts, the RuIr alloy catalysts exhibited higher activity and stability in seawater electrolysis due to their greater number of reactive sites and solubility resistance. The RuIr alloy has an overpotential of 75 mV@10 mA cm-2, which is similar to that of Pt/C (73 mV), and can operate stably for 100 hours in alkaline seawater. Density functional theory (DFT) calculations indicate that hydrogen atoms adsorbed at the top sites of Ru and Ir atoms are more favorable for HER and are most likely to be the reactive sites. This work provides a reference for developing highly efficient and stable catalysts for seawater electrolysis.

Mutational analysis of MpPhy reveals magnetoreception and photosensitivity involvement in secondary metabolites biosynthesis in Monascus purpureus.

Light or low frequency magnetic field (LF-MF) as one of the cultivation environments affects secondary metabolites (SMs) production of M. purpureus. Phytochrome (Phy) is a hybrid histidine kinase possessing dual properties of photoreceptor and kinase to sense red and far-red light. The interaction effects of LF-MF and light on SMs of M. purpureus was investigated by knocking out the Phy-like gene in M. purpureus (MpPhy) by homologous recombination. A MpPhy-deletion (ΔMpPhy) strain produced less Monascus pigments (MPs) and monacolin K (mon K) than the wild-type (WT) strain and reduced citrinin production by 78.3% on 10th day but didn't affect the biomass. These results indicated that the MpPhy gene is involved in SMs biosynthesis of M. purpureus. MPs production in WT was decreased significantly when the inoculum was exposed to white/blue/green/red light (500 Lux). But it in ΔMpPhy was no significant difference when exposed to white/red light. The colony size of ΔMpPhy was smaller on potato dextrose agar media containing 0.01% SDS. These results indicated that the deletion of MpPhy gene affected the aerial hyphae and increased sensitivity to cell membrane stress but decreased sensitivity to red light. The inoculum of both WT and ΔMpPhy was exposure to the LF-MF (50 Hz). The accumulation of WT secondary metabolites was not changed, while SMs production of ΔMpPhy was significantly enhanced under exposed to 2.0 mT LF-MF. This indicated that the decrease of SMs caused by the deletion of MpPhy gene was restored by LF-MF. It revealed that there is a crosstalk between magnetoreception and photosensitivity.

Low-Frequency Magnetic Field of Appropriate Strengths Changed Secondary Metabolite Production and Na+ Concentration of Intracellular and Extracellular Monascus purpureus.

Monascus purpureus is used to yield edible pigments accompanied by mycotoxin-citrinin. A low-frequency (<300 Hz) magnetic field (LF-MF) affects microbial metabolism. The link of LF-MF with secondary metabolites and intracellular and extracellular Na+ levels in M. purpureus was determined. The fermentation broth was exposed to LF-MF during the first 2 days of fermentation and continuously cultured at 30°C and 200 rpm until the 8th day of fermentation. Results showed that LF-MF treatments didn't affect the growth of M. purpureus in liquid-state fermentation. Compared with the control, citrinin production showed a decrease of 45.0%, while yellow, red, and orange pigment production showed an increase of 72.9, 73.9, and 40.1%, respectively, with LF-MF treatment of 1.6 mT. This was in agreement with downregulation of pksCT and ctnA, and upregulation of pksPT, pigR, veA, and laeA at the transcriptional level. Moreover, 1.6 mT LF-MF exposure caused the transfer of Na+ from extracellular to intracellular, which was validated through the upregulation of transmembrane sensor synthesis genes and the changes in the relative expression levels of the P-type ATPase and protein phosphatase genes. This study established that LF-MF could inhibit citrinin and stimulate pigment production and change intracellular and extracellular Na+ concentrations. Bioelectromagnetics. 2020;41:289-297 © 2020 Bioelectromagnetics Society.

Correction: Zhen, Z. et al. NaCl Inhibits Citrinin and Stimulates Monascus Pigments and Monacolin K Production. Toxins 2019, 11, 118.

The authors wish to make the following correction to their paper [...].

NaCl Inhibits Citrinin and Stimulates Monascus Pigments and Monacolin K Production.

Applications of beneficial secondary metabolites produced by Monascus purpureus (M. purpureus) could be greatly limited for citrinin, a kidney toxin. The link of NaCl with cell growth and secondary metabolites in M. purpureus was analyzed with supplementations of different concentrations of NaCl in medium. The content of citrinin was reduced by 48.0% but the yellow, orange, red pigments and monacolin K productions were enhanced by 1.7, 1.4, 1.4 and 1.4 times, respectively, compared with those in the control using NaCl at 0.02 M at the 10th day of cultivation. NaCl didn't affect the cell growth of M. purpureus. This was verified through the transcriptional up-regulation of citrinin synthesis genes (pksCT and ctnA) and the down-regulation of the Monascus pigments (MPs) synthesis genes (pksPT and pigR). Moreover, the reactive oxygen species (ROS) levels were promoted by NaCl at the 2nd day of cultivation, and then inhibited remarkably with the extension of fermentation time. Meanwhile, the activities of superoxide dismutase (SOD) and catalase (CAT), and the contents of total glutathione (T-GSH) were significantly enhanced in the middle and late stages of cultivation. The inhibition effect on colony size and the growth of aerial mycelia was more obvious with an increased NaCl concentration. Acid and alkaline phosphatase (ACP and AKP) activities dramatically increased in NaCl treatments. NaCl could participate in secondary metabolites synthesis and cell growth in M. purpureus.

Protective effect of niacinamide on interleukin-1beta-induced annulus fibrosus type II collagen degeneration in vitro.

The protective effect of niacinamide on interleukin-1beta (IL-1beta)-induced annulus fibrosus (AF) type II collagen degeneration in vitro and the mechanism were investigated. Chiba's intervertebral disc (IVD) culture models in rabbits were established and 48 IVDs from 12 adult Japanese white rabbits were randomly divided into 4 groups: normal control group, niacinamide-treated group, type II collagen degneration group (IL-1beta) and treatment group (niacinamide+IL-1beta). After culture for one week, AFs were collected for inducible nitric oxide synthase (iNOS), cysteine containing aspartate specific protease-3 (Caspase-3) and type II collagen immunohistochemical examination, and type II collagen reverse transcription polymerase chain reaction (RT-PCR). The results showed that rate of iNOS positive staining AF cells in the 4 groups was 17.6%, 10.9%, 73.9% and 19.3% respectively. The positive rate in treatment group was significantly lower than in the type II collagen degeneration group (P<0.01). Rate of Caspase-3 positive staining AF cells in the 4 groups was 3.4%, 4.2%, 17.6% and 10.3% respectively. The positive rate in treatment group was lower than in the type II collagen degeneration group (P<0.01). Type II collagen staining demonstrated that lamellar structure and continuity of collagen in treatment group was better reversed than in the degeneration group. RT-PCR revealed that the expression of type II collagen in treatment group was significantly stronger than that in type II collagen degeneration group (P<0.01). It was concluded that niacinamide could effectively inhibit IL-1beta stimulated increase of iNOS and Caspase-3 in AF, and alleviate IL-1beta-caused destruction and synthesis inhibition of type II collagen. Niacinamide is of potential for clinical treatment of IVD degeneration.

Interleukin-6 protects annulus fibrosus cell from apoptosis induced by interleukin-1 beta in vitro.

OBJECTIVE: To investigate the effect of interleukin-6 (IL-6) on the apoptosis of annulus fibrosus (AF) cell induced by interleukin-1beta (IL-1beta). METHODS: Cultured AF cells were divided into 6 groups and treated with no drug, 10 ng/mL IL-6, 10 ng/mL IL-1beta, 10 ng/mL IL-1beta and Z-VAD-FMK (a caspase-9 inhibitor), 10 ng/mL IL-1beta and 10 ng/mL IL-6, 10 ng/mL IL-1beta and 100 ng/mL IL-6, respectively. After three days of culture, the apoptosis rate, the positive rates of caspase-3, -8, and -9 of AF cells were detected with flow cytometry. RESULTS: The apoptosis rates of cells in group 1 to 6 were 2.67% +/- 1.08%, 2.71% +/- 0.53%, 20.37% +/- 1.57%, 11.34% +/- 0.67%, 18.17% +/- 0.74%, and 9.42% +/- 1.08%, respectively. There was no significant difference between group 1 and 2, while the apoptosis rates of group 4, 5, and 6 were significantly lower than group 3 (P = 0.001, P = 0.172, and P = 0.001, respectively). Positive rates of caspase-3 in group 5 (12.35% +/- 0.64%) and 6 (9.26% +/- 0.36%) were significantly lower than group 3 (17.14% +/- 0.72%; P = 0.001 and P < 0.001, respectively). And positive rates of caspase-9 in group 5 (15.13% +/- 1.45%) and 6 (10.17% +/- 2.50%) were significantly lower than group 3 (19.4% +/- 0.98% ; P = 0.014 and P = 0.004, respectively). But there was not obvious change of caspase-8 activity after IL-6 was added. CONCLUSION: IL-6 is capable of protecting AF cells from IL-1beta induced apoptosis in vitro. Mechanism of the protection is related with the inhibition of caspase-3 and -9 activities.

Up-regulation of niacinamide in intervertebral disc aggrecan in vitro.

The regulatory effects of niacinamide (Nia) on intervertebral disc (IVD) aggrecan in vitro was investigated. Chiba's 10 ng/mL interleukin-1 (IL-1)-induced rabbit IVD degeneration model in vitro was established. 0.5, 0.25 and 0.05 mg/mL Nia was added to normal and degenerated IVDs for intervention. On the first and second week after intervention, safranin O-fast green staining intensity and glycosaminoglycan (GS) content were measured. The expression of aggrecan core protein was detected by RT-PCR. The results showed: (1) After treatment with 0.5 mg/mL Nia for one week, the GS content in nucleus pulposus (NP) was increased by 44.8% as compared with control group (P < 0 01); The GS content in IL-1 induction groups was increased with the increase of Nia concentrations: After treatment with 0.5 mg/mL for one week, the GS content in NP was increased by 68.3% as compared with control group (P < 0.01). After two weeks, GS content in NP and fibrous rings was still higher than in control group at the same period (P < 0.01) and untreated group (P < 0.01). (2) Safranin O-fast green staining revealed that with the increase of Nia concentrations, staining density in NP and fibrous rings was increased and histological structure damage to IVDs by IL-1beta was alleviated. (3) RT-PCR showed that the expression of core protein gene in IL-1beta-induced degenerated IVDS was increased with the increase of Nia concentrations. It was concluded that under conditions in vitro, Nia could up-regulate the expression of aggrecan in IVDs and protect IVDs from IL-1beta-induced degeneration at least partially, which offers a potential choice for IVD degeneration clinical therapy.

Effect of exogenous p16ink4a and hRb1 genes on cell cycle regulation of osteosarcoma cell.

To study the effect on regulation of cell cycle of osteosarcoma cell line MG63 tranceduced with exogenous p16ink4a and hRb1 genes, pIRES-p16ink4a-hRb1, pIRES-p16ink4a and pIRES-hRb1 plasmids were constructed by gene recombination technology. The recombinant plasmid was transferred into osteosarcoma cell line MG63 by metafectene, and the resistant clones were selected by G418 selective medium. mRNA and protein expression of osteosarcoma cell line were assayed by RT-PCR and Western-Blot respectively. Cell cycle and apoptosis were analyzed by subG1 flow cytometric. Cell proliferation was tested by MTT. In the genome of these transfected target cells, the expression of p16ink4a and hRb1 mRNA and protein were detected respectively in vitro. It was demonstrated with subG1 flow cytometric analysis and MTT method that p16ink4a and hRb1 genes cooperation more significantly inhibited cell growth and induced a more marked G1 arrest and apoptosis than p16ink4a/hRb1 alone (P < 0.01). Coexpression of exogenous p16ink4a with hRb1 broke the regulatory feedback loop of p16ink4a-cyclinD1 /CDK-hRb1 and played a more significant role in inhibiting cell growth as well as inducing cell apoptosis than p16ink4a or hRb1 did alone in vitro.

Ad/CMV- hTGF-beta1 treats rabbit intervertebral discs degeneration in vivo.

To investigate therapeutic efficiency of Ad/CMV- hTGF-beta1 gene for rabbit intervertebral disc degeneration model. 60 Japanese white rabbits were selected to form the 1.5-L6 Anterior-Lateral-Anulus-Fibrosus-Incision-Induced model in order to simulate human intervertebral disc degeneration. 36 rabbits, whose corresponding intervertebral discs were injected with 20 microl (10 x 10(6) pfu) of Ad/CMV- hTGF-beta1 gene, constituted the therapy group, 12 were injected with 20 microl (10 x 10(6) pfu)of Ad/CMV-LacZ gene as comparison group, while 12 were only injected with equivalent capacity of saline for empty comparison group, 3 weeks after injection, examples were taken for investigation of HE staining, MRI, Western Blotting and immunohistochemical research TGF-beta1. Wide distribution of TGF-beta1 was detected by immunohistochemical research in the degenerated annulus fibrosus after injection. Western Blotting research showed significant increase of TGF-beta1 content in intervertebral discs treated with TGF-beta1 gene than comparison groups. MRI signal transformed from low to comparatively high and that intervertebral disc pathological degree improved. Ad/CMV- hTGF-beta1 gene transfection is a potential method to increase TGF-beta1 content and reverse intervertebral disc degeneration.