In-situ growth of nitrogen-doped carbonized polymer dots on black phosphorus for electrochemical DNA biosensor of Escherichia coli O157: H7.

Sensitive and accurate detection technology for pathogenic bacteria is of great social and economic significance in foodborne disease and food safety. In this paper, a novel portable electrochemical DNA biosensor for the detection of specific DNA sequence of Escherichia coli (E. coli) O157: H7 was constructed. To enhance the performance of the electrochemical sensor, a functionalized nitrogen-doped carbonized polymer dots in-situ grown on few-layer black phosphorus (N-CPDs@FLBP) was synthesized and used as the modifier on the surface of screen-printed electrode. Combining gold nanoparticles as immobilization matrix and methylene blue as electrochemical indicator, the analytical performance of this electrochemical DNA biosensor was evaluated using standard complementary ssDNA sequence in the linear concentration range from 1.0 × 10-19 to 1.0 × 10-6 mol/L with a low detection limit as 3.33 × 10-20 mol/L (3 σ). Furthermore, the portable electrochemical DNA biosensor was proposed based on polymerase chain reaction amplification for the detection of the E. coli O157: H7 genomic DNA from chicken meat, which verified the feasibility for practical samples detection. The research has great theoretical and practical significance for the development of electrochemical biosensor of pathogenic bacteria.

Regulation strategy for nutrient-dependent carbon and nitrogen stoichiometric homeostasis in freshwater phytoplankton.

Phytoplankton carbon (C) and nitrogen (N) stoichiometric homeostasis plays an important role in aquatic ecosystems. Their C:N ratio is a result of cellular metabolic balance, and the relevant regulatory strategy for its plasticity is still unclear. Therefore, a field survey of seven reservoirs in Tianjin, North China, was conducted to understand variations in phytoplankton C:N ratios, and a laboratory culture of Chlamydomonas reinhardtii was performed to understand the relevant regulation strategy for cellular C-N stoichiometric homeostasis under different C and N availability by using transcriptome sequencing and Nano SIMS and C stable isotope analyses. The results indicated that CO2 limitation had no significant effect on the phytoplankton C:N ratio in either scene, whereas limitation of dissolved inorganic N induced a 35% higher ratio in the field and a 138% higher ratio in the laboratory. Under CO2 limitation, algal CO2-concentrating mechanisms were operated to ensure a C supply, and coupled C-N molecular regulation remained the cellular C:N ratio stable. Under nitrate limitation, differentially expressed gene-regulated intensities increase enormously, and their increasing proportion was comparable to that of the algal C:N ratio; cellular metabolism was reorganized to form a "subhealthy" C-N stoichiometric state with high C:N ratios. In addition, the N transport system had a specific role under CO2 and nitrate limitations. Our study implies that algal stoichiometric homeostasis depends on the involved limitation element and will help to deepen the understanding of C-N stoichiometric homeostasis in freshwater phytoplankton.

Artesunate inhibits Sjögren's syndrome-like autoimmune responses and BAFF-induced B cell hyperactivation via TRAF6-mediated NF-κB signaling.

BACKGROUND: Hyperactivation of B cells by activators has been demonstrated to play a central role in the pathogenesis of Sjögren's syndrome (SS). In this study, we found that artesunate (ART) can attenuate BAFF-induced B cell hyperactivation and SS-like symptoms in NOD/Ltj mice. PURPOSE: To determine the efficacy of ART in attenuating SS-like symptoms in vivo and explore the underlying mechanism in vitro. STUDY DESIGN: ART was intragastrically injected into SS-like NOD/Ltj mice. The cytokine hsBAFF was used to activate Raji and Daudi B cells to mimic B cell hyperactivation in vitro. METHODS: The efficacy of ART in inhibiting SS progression was studied in NOD/Ltj mice. Salivary flow rate, the number of lymphocytic infiltration foci, the level of autoantibodies and the extent of B cell infiltration were measured in the indicated groups. CCK-8 assays, flow cytometry-based EdU staining and Annexin V/PI staining were also used to detect the effect of ART on the survival and proliferation mechanism in BAFF-induced Raji and Daudi cells. Further studies determined that TRAF6 degradation is a potential mechanism by which ART determines B cell fate. RESULTS: Treatment with ART inhibited lymphocytic foci formation, B cell infiltration and autoantibody secretion in SS-like NOD/Ltj mice. In vitro assay results indicated that ART effectively inhibited BAFF-induced viability, survival and proliferation of neoplastic B cells. Mechanistically, ART targeted BAFF-activated NFκB by regulating the proteasome-mediated degradation of TRAF6 in Raji and Daudi cells. CONCLUSION: ART ameliorated murine SS-like symptoms and regulated TRAF6-NFκB signaling, thus determining survival and proliferation of B cells.

miR-196b-5p controls adipocyte differentiation and lipogenesis through regulating mTORC1 and TGF-ß signaling.

MicroRNAs have been reported to play a role in adipogenesis and obesity. This study was performed to investigate the role of miR-196b-5p in adipogenesis and the mechanism involved. The data revealed that miR-196b-5p expression increased in primary or established marrow stromal progenitor cells after adipogenic treatment. Supplementing miR-196b-5p in the progenitor cells stimulated adipogenic differentiation and lipogenesis, along with the induction of adipogenic and lipogenic factors. Conversely, inhibition of endogenous miR-196b-5p blocked adipogenesis and lipogenesis. Tuberous sclerosis 1 (Tsc1) and transforming growth factor-ß receptor 1 (TGFBR1) were demonstrated to be the direct target genes of miR-196b-5p. Supplementing miR-196b-5p activity in progenitor cells reduced the protein level of TSC1 and activated mammalian target of rapamycin complex 1 (mTORC1) signaling. We further demonstrated that the perturbation of TSC1 in progenitor cells altered the trend of adipogenic differentiation and lipogenesis. Overexpression of Tsc1 or inactivation of mTORC1 signaling attenuated the stimulation of adipogenic differentiation and lipogenesis by miR-196b-5p. Overexpression of Tgfbr1 also partially blocked the adipogenic effect of miR-196b-5p. Further investigations demonstrated that zinc finger E-box-binding homeobox 1 (ZEB1) transcriptionally upregulated miR-196b-5p expression. The current study suggests that miR-196b-5p promotes adipogenic differentiation and lipogenesis in progenitor cells through targeting TSC1 and TGFBR1 and therefore regulating mTORC1 and TGF-ß signaling.

Analysis of pharmacological mechanisms and targets mining of Wuzi-Yanzong-Wan for treating non-obstructive oligoasthenospermia.

As a classical traditional Chinese medicine, Wuzi-Yanzong-Wan (WZYZW) has been widely applied for several centuries to treat non-obstructive oligoasthenozoospermia (NOA), although its pharmacological mechanisms remain largely unknown. In this study, both plasma and urine metabolomics profiling was first analysed to explore the therapeutic mechanisms of WZYZW in NOA rats induced by removal of the unilateral testicle. Then, 106 identified compounds comprising WZYZW (our previous work), for which putative targets were discovered using systems pharmacology, were systematically analysed via mRNA microarrays to validate their putative targets. Finally, metabolomics-tested WZYZW-regulated metabolites were connected with validated targets using Spearman correlation analysis to further confirm the targets from a biological perspective. The results suggested that WZYZW plays key roles in modulating the concentrations of 18 metabolites in the metabolism of amino acids, lipids and so on, normalizing the metabolic phenotype and regulating metabolic disorders. Moreover, 27 targets of WZYZW (23 compounds) against NOA were validated, and metabolomics-tested metabolites were also found to be significantly related to these identified targets, suggesting that these targets and compounds are worthy of further research. This work offers the first systematic investigation of the efficacy of WZYZW against NOA and illustrates a practicable approach for explaining the molecular mechanisms of multicomponent drugs.

Historical record of nutrients inputs into the Xin'an Reservoir and its potential environmental implication.

The Xin'an Reservoir is an important water supply source and water conservation area for the Qiantang River. However, after the occurrence of the two algae blooms in 1998 and 1999, the safety of water quality has been put into question. In order to study the historical deposition of nutrients, sediment cores were collected in different regions from the Xin'an Reservoir. The stable isotopes δ13C and δ15N, nutrients, total organic carbon (TOC), and inorganic carbon (IC) in the sediment cores were determined. Radiometric methods (210Pb and 137Cs) were used to obtain sediment chronologies. Spatially, it was found that the average total nitrogen (TN) content in the upper 5 cm of sediments increased from 0.21% in the riverine zone, to 0.33%, and then to 0.57% in the lacustrine zone. The average TP content in the upper 5 cm increased from 0.67 g kg-1 in the riverine zone, to 1.03 g kg-1 in the estuary region, and then to 1.65 g kg-1 in the lacustrine zone. In addition, TOC levels showed a distinct increase from 1.42% in the bottom to 5.97% in the surface of the lacustrine zone. These results demonstrated that although primary productivity and the input of nutrients constantly increased in recent years, algae blooms rarely occurred in the Xin'an Reservoir, due to "depth effect" and an aquatic environment protection-oriented fishery policy. However, high TOC flux and high bio-available phosphorus and nitrogen in surface sediment demonstrated that the reservoir is still confronted with the potential risk of algae blooms.

Excessive input of phosphorus significantly affects microbial Fe(III) reduction in flooded paddy soils by changing the abundances and community structures of Clostridium and Geobacteraceae.

Microbial Fe(III) reduction can make an excellent contribution to the bioremediation of contaminated environments and potentially reduce methanogenesis. Excessive input of phosphorus (P) by P fertilizer application and eutrophied irrigation water might have a substantial influence on the process of microbial Fe(III) reduction in flooded paddy soils. To evaluate the effect of P application on microbial Fe(III) reduction, the responses of Clostridium and Geobacteraceae communities to different concentrations of P addition (CK: 0mmolPkg-1 soil; P1: 3.3mmolPkg-1 soil; P2: 20mmolPkg-1 soil) were investigated in anaerobically incubated paddy slurries. P addition significantly inhibited Fe(III) reduction during the early stage of incubation (from days 0 to 20). Compared with the CK treatment, the maximum Fe(III) reduction rate (Vmax) in treatments P1 and P2 remarkably decreased by 0.281 and 0.439mg·g-1·d-1, respectively. However, the addition of P had no significant effect on Fe(III) reduction during the later stage of incubation (after 20days). The abundances of Clostridium and Geobacteraceae were suppressed by P addition, and the suppression effect was more obvious with higher P concentration. P addition significantly changed the community structures of Clostridium and Geobacteraceae during the entire incubation. The communities of Clostridium and Geobacteraceae were closely correlated with the process of Fe(III) reduction. In conclusion, P addition could inhibit the microbial reduction of Fe(III) during the early stage of incubation by reducing the abundances and altering the community structures of Clostridium and Geobacteraceae, however, the inhibition could be eliminated with increased incubation time. This study demonstrates that soil microbial communities are sensitive to excessive P application, which can jointly impact relevant biogeochemical processes in flooded paddy soils.

miR-148a-3p regulates adipocyte and osteoblast differentiation by targeting lysine-specific demethylase 6b.

Recent emerging studies of miRNAs in mesenchymal stem cell commitment toward adipocyte and osteoblast provide new insights for the understanding of the molecular basis of adipogenesis and osteogenesis. The current study revealed that miR-148a-3p was altered in primary cultured marrow stromal cells and established stromal ST2 line after adipogenic and/or osteogenic treatment. Supplementing miR-148a-3p activity inhibited cell growth and induced ST2 to differentiate into mature adipocytes. Conversely, inactivation of the endogenous miR-148a-3p suppressed ST2 to fully differentiate. By contrast, supplementation of the miR-148a-3p blunted osteoblast differentiation. Lysine-specific demethylase 6b (Kdm6b), a recently identified regulator of osteoblast differentiation was shown to be a direct target of miR-148a-3p by using the luciferase assay. Overexpression of Kdm6b attenuated miR-148a-3p stimulation of adipogenic differentiation. Taken together, our study provides evidences that miR-148a-3p reciprocally regulates adipocyte and osteoblast differentiation through directly targeting Kdm6b.

[Overdose of iodine on expression of CCK gene in rat brains].

OBJECTIVE: To observe the effect of overdose iodine on the expression of CCK gene in brains of rats and identify the possible mechanisms. METHODS: One-month weaning Wistar rats were randomly divided into five groups which were fed with normal feedstuff and water supplemented with different concentrations of potassium iodide, named A group (iodine ration was about 6.15 microg per day), B group (iodine ration was about 30.75 microg per day), C group (iodine ration was about 61.5 microg per day), D group (iodine ration was about 307.5 microg per day) and E group (iodine ration was about 615 microg per day). Rats were sacrificed after being fed for three or six months. Then serum thyroid hormones were measured by radioimmunoassay and the mRNA level of CCK gene was studied by using RT-PCR technique. RESULTS: At the end of three months, the values of thyroid hormones in E group [TT4 (45.2 +/- 13.7) nmol/L, TI'3 (0.65 +/- 0.20) nmol/L, FT3 (0.93 +/- 0.45) pmol/L, FT4 (7.07 +/- 2.43) pmol/L, rT3 (0.15 +/- 0.04) nmol/L] were all lower than those in A group [TT4 (76.0 +/- 18.8) nmol/L, TT3 (1.34 +/- 0.41) nmol/L, FT3 (2.45 +/- 0.62) pmol/L, FT4 (15.12 +/- 3.40) pmol/L, rT3 (0.24 +/- 0.04) nmol/L]. There were significant differences between E group and A group on the levels of serum TH (F values are 14.68, 16.03, 21.16, 20.25, 13.52 respectively, P < 0.01); FT3 levels in C and D groups were significantly decreased as compared to A and B groups (F = 21.16, P < 0.05). rT3 level in D group was significantly decreased compared with A,B and C groups (F = 13.52, P < 0.05). At the end of six months, the levels of serum TH in E group (TT4 (51.84 +/- 15.83) nmol/L, TT3 (0.77 +/- 0.22) nmol/L, FT4 (6.88 +/- 2.23) pmol/L, FT3 (0.74 +/- 0.28) pmol/L, rT3 (0.14 +/- 0.03) nmol/L) were lower than those in any other groups (F values were 6.05, 12.22, 11.25, 13.42, 5.89 respectively, P < 0.05). At the end of both three and six months, the mRNA levels of CCK gene in E group were lower than any other groups (F values were 4.04, 3.95 respectively, P < 0.01). The results of correlation analysis showed that serum FT4 had linear correlation with levels of CCK mRNA (r values were 0.990, 0.948 respectively; P < 0.05); However serum FT3 had no linear correlation with the levels of CCK mRNA (r values are 0.970, 0.932 respectively). CONCLUSIONS: Exposure to overdose of iodine (iodine ration was 100-fold higher than that of A group) could decrease the mRNA level of CCK gene. Compared with FT3, FT4 might have more important role on the regulation of CCK mRNA induced by excess of iodine.

[Comparison study of effects of rhizoma drynariae and estrogen on osteoporosis in ovariectomized rats].

OBJECTIVE: To study the therapeutic effects of Rhizoma Drynariae and estrogen on osteoporosis in ovariectomized (OVX) rats. METHODS: Fifty-five female rats were randomly divided into 5 groups, the normal control (normal),the sham operated (sham), the model, the estrogen, and the Rhizoma drynariae (RD) groups; ovariectomized rats were used as postmenopausal osteoporosis model. The changes of morphology and dynamic parameters in different groups were determined by bone histomorphometry. RESULTS: Compared with the model group, the trabecular volume (TBV/TTV) , trabecular thickness (MTPT) and density (MTPD) in the other four groups were significantly increased, while the trabecular template spacing (MTPS) and the ratio of trabecular surface to trabecular volume (TBS/TBV) significantly decreased (P <0. 05); and the osteoid surface (TOS), single label surface [Sfract (s) ] ,double label surface [Sfract (d) ] and bone formation rate (Svf) also decreased,while osteoid maturation period (OMP) increased in the latter four groups. No significant difference of cortical width (MCW) was found between these 5 groups. Compared with the normal and sham groups, TOS, Sfract ( s) , Sfract ( d) , Svf in the estrogen and RD groups increased significantly, while OMP decreased; no significant difference was found in other parameters. CONCLUSION: Rhizoma Drynariae has the similar effect with estrogen in maintaining normal trabecular structure and connection by inhibiting the increased bone turnover of postmenopausal osteoporosis.