Nitrogen Forms Regulate the Response of Microcystis aeruginosa to Nanoplastics at Environmentally Relevant Nitrogen Concentrations.

As essential primary producers, cyanobacteria play a major role in global carbon and nitrogen cycles. Though the influence of nanoplastics on the carbon metabolism of cyanobacteria is well-studied, little is known about how nanoplastics affect their nitrogen metabolism, especially under environmentally relevant nitrogen concentrations. Here, we show that nitrogen forms regulated growth inhibition, nitrogen consumption, and the synthesis and release of microcystin (MC) in Microcystis aeruginosa exposed to 10 µg/mL amino-modified polystyrene nanoplastics (PS-NH2) with a particle size of 50 nm under environmentally relevant nitrogen concentrations of nitrate, ammonium, and urea. We demonstrate that PS-NH2 inhibit M. aeruginosa differently in nitrate, urea, and ammonium, with inhibition rates of 51.87, 39.70, and 36.69%, respectively. It is caused through the differences in impairing cell membrane integrity, disrupting redox homeostasis, and varying nitrogen transport pathways under different nitrogen forms. M. aeruginosa respond to exposure of PS-NH2 by utilizing additional nitrogen to boost the production of amino acids, thereby enhancing the synthesis of MC, extracellular polymeric substances, and membrane phospholipids. Our results found that the threat of nanoplastics on primary producers can be regulated by the nitrogen forms in freshwater ecosystems, contributing to a better understanding of nanoplastic risks under environmentally relevant conditions.

One facile fluorescence strategy for sensitive determination of baicalein using trypsin-templated copper nanoclusters.

Herein, we established a fluorescent detection platform for baicalein (Bai) based on copper nanoclusters, which were prepared by using copper sulfate as the precursor, trypsin (Tryp) as the template and hydrazine hydrate as the reducing agent. The entire preparation and testing process were rapid, facile and green. Many characterization methods, such as UV-vis absorption spectroscopy, fluorescence spectroscopy, fourier transform infrared spectroscopy (FT-IR), fluorescence lifetime, transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS), were applied for the analysis of trypsin-templated copper nanoclusters (Cu NCs@Tryp). The Cu NCs@Tryp released green fluorescence at maximum emission wavelength of 457 nm under maximum excitation wavelength of 377 nm. More importantly, the fluorescence of Cu NCs@Tryp was efficiently quenched by Bai. According to this phenomenon, a facile, rapid and selective turn-off fluorescence probe for Bai sensing was developed. Under the optimized testing conditions, the ln(F0/F) value and concentration of Bai displayed excellent linear relationship changing from 0.5 to 60 µM (R2 = 0.9969), and the detection limit was 0.078 µM. Furthermore, the Cu NCs@Tryp has been successfully employed to measure the amount of Bai in bovine serum samples with satisfactory recoveries.

MiR-181a contributes to bufalin-induced apoptosis in PC-3 prostate cancer cells.

BACKGROUND: Bufalin is a major active compound of cinobufacini, which comes from dried toad venom and has been used for treatments of various cancers in China for many years. A number of studies have demonstrated that bufalin can induce apoptosis in some cancers. However, effects and mechanism of bufalin on prostate cancer cells remain unknown. METHODS: Apoptosis assay was measured by the annexin-V/PI flow cytometric assay. Western blot was used to measure Caspase-3 and Bcl-2. qRT-PCR was used to measure the relative expression of miR-181a. RESULTS: Bufalin was found to induce the expression of miR-181a, a small non-coding RNA believed to induce apoptosis by repressing its target gene, BCL-2. In prostate cancer PC-3cell line, bufalin-induced apoptosis can be largely attenuated by a miR-181a inhibitor, which blocked bufalin-induced Bcl-2 reduction and caspase-3 activation. CONCLUSIONS: Our dataindicatedthat miR-181a mediates bufalin-induced apoptosis in PC-3 cells. Thus, we presented here a new pharmacological mechanism for bufalin in anti-tumor therapy.

Preventive effects of jiedu granules combined with cinobufacini injection versus transcatheter arterial chemoembolization in post-surgical patients with hepatocellular carcinoma: a case-control trial.

OBJECTIVE: To investigate the therapeutic effects of Jiedu granules, a Chinese medicine (CM) compound, plus cinobufacini injection, which was extracted from skin of Bufo bufo gargarizans Cantor, to prevent the recurrence of hepatocellular carcinoma (HCC) after surgical resection. METHODS: In this case-control trial, a total of 120 patients who stayed in Changhai Hospital were enrolled from December 2001 to December 2006. Sixty patients were treated with Jiedu granules plus cinobufacini injection to prevent tumor recurrence after operation (CM group) and 60 patients were treated with transcatheter arterial chemoembolization (TACE) after operation (TACE group). Progression-free survival (PFS) and overall survival (OS) rates were determined to evaluate the therapeutic effects of post-operative management of patients with HCC. RESULTS: PFS in the CM group was 18.07 months [95% confidence interval (CI): 12.49-23.65] and the 1-, 2-, 3-, 4- and 5-year PFS rates were 61%, 39%, 26%, 22% and 12%, respectively. PFS in the TACE group was 8.03 months (95% CI: 6.63-9.44) and the 1-, 2-, 3-, 4- and 5-year PFS rates were 34%, 11%, 7%, 2% and 0%, respectively. There was significant difference in survival rate between the two groups (P<0.01). The mean survival time (MST) of patients in the CM group was 49.53 months versus 39.90 months of the TACE group. The 1-, 2-, 3-, 4- and 5-year survival rates were 90%, 82%, 80%, 70% and 63%, respectively, in the CM group, and 79%, 70%, 60%, 60% and 36%, respectively, in the TACE group. There was significant difference in survival time between the two groups (P=0.045). CONCLUSIONS: Jiedu granules plus cinobufacini injection, a combination that is commonly used for post-operation management of HCC, can postpone tumor recurrence and metastasis, prolong the survival time and increase the survival rate of post-surgical patients with HCC. However, these findings need to be confirmed in a prospective, randomized controlled trial.