[Environmental impact differences in Qingtian rice-fish culture system at different management scales in the context of land transfer: An empirical study with the carbon footprint method.] / åœŸåœ°æµè½¬èƒŒæ™¯ä¸‹ä¸åŒç»è¥è§„æ¨¡é’ç”°ç¨»é±¼å ±ç”Ÿç³»ç»Ÿçš„çŽ¯å¢ƒå½±å“å·®å¼‚­­åŸºäºŽç¢³è¶³è¿¹çš„å®žè¯ç ”ç©¶.

Under rapid industrialization and urbanization, the conservation and management of agricultural heritage systems is facing many threats and challenges, such as the massive outflow of working labor, land abandonment, and the difficulty in maintaining traditional knowledge systems. Promoting land transfer and carrying out moderate-scale management play an active role in the conservation of agricultural heritage systems. While land transfer brings economic benefits to heritage sites, its environmental impacts to heritage sites are worthy of attention. However, empirical studies are scarce. This study took Qingtian rice-fish culture system in Zhejiang Province as an example, which was designated as Globally Important Agricultural Heritage Systems (GIAHS) in 2005. Small farmer management model and land scale management model were distinguished, while the life cycle method was used to calculate the carbon footprints of two models. The results showed that the carbon footprints of small farmer management model and land scale management model were 6510.80 and 5917.00 kg CO2-eq·hm-2, respectively, while the carbon footprints per unit output were 0.13 and 0.10 kg CO2-eq·yuan-1, respectively. Compared with small farmer management model, land scale management model had lower greenhouse gas emission and lower environmental impact of per unit output. As farmers expanded the scale of land management, local greenhouse gas emissions had been reduced by 4097.20 kg CO2-eq. Furthermore, the accumulation of CH4 in agricultural production accounted for the largest proportion of carbon footprint. The input of compound fertilizer among agricultural production materials was next to CH4 accumulation, becoming the second largest source of greenhouse gas emission. Corn and wheat being used as fish feed also had a significant impact on greenhouse gas emission in small farmer management model. Therefore, the promotion of moderate scale land management is conducive to the win-win of economic and environmental benefits of traditional agricultural systems and plays an important role in the conservation of agricultural heritage systems.

[Expression, purification and activity identification of ZtaN-p23 fusion protein in Escherichia coli of Epstein-Barr virus].

AIM: To construct the prokaryotic expression plasmid pGEX-4T-1-BZLF1N-BLRF2, and express it in Escherichia coli. METHODS: The EB virus BZLF1N gene and BLRF2 gene were amplified by RT-PCR respectively. Then, the two genes were linked by splicing overlap extension PCR method and inserted into the vector pGEX-4T-1, and the recombinant plasmid pGEX-4T-1-BZLF1N-BLRF2 was transformed into E.coli BL21 (DE3) strain. The expression protein ZtaN-p23 was analysed by SDS-PAGE and immunoreactivity was proved by Western blotting. RESULTS: Restriction enzyme digestion and DNA sequencing showed recombinant plasmid constructed successfully. The expression product ZtaN-p23 with the molecular weight 46000 was located in the cytoplasm and insoluble. The ZtaN-p23 up to 95% purity was obtained after purified using affinity chromatography. Western blotting showed fusion protein possessed a well bioactivity and specificity. CONCLUSION: The fusion gene BZLF1N-BLRF2 is successfully constructed and effectively expressed in E.coli, which lay the foundation for further research on its biological properties and functions.

Effects of DNMT1 silencing on malignant phenotype and methylated gene expression in cervical cancer cells.

BACKGROUND: DNA methylation has been widely used in classification, early diagnosis, therapy and prediction of metastasis as well as recurrence of cervical cancer. DNMT methyltransferase 1 (DNMT1), which plays a significant role in maintaining DNA methylation status and regulating the expression of tumor suppressor genes. The aim of this research was to investigate the relationship between DNMT1 and abnormal methylation of tumor suppressor genes and malignant phenotype in cervical cancer. METHODS: Levels of DNMT1 mRNA and protein were detected using qPCR and Western blot, respectively. Cell proliferation was analyzed by MTT and apoptosis was performed by Annexin V-FITC/PI double staining flow cytometry, respectively. MeDIP-qPCR and qPCR were performed to measure demethylation status and mRNA re-expression level of 7 tumor-suppressor genes (CCNA1, CHFR, FHIT, PAX1, PTEN, SFRP4, TSLC1) in Hela and Siha cells after silencing DNMT1. RESULTS: The average expression levels of DNMT1 mRNA and protein in Hela and Siha cells were decreased significantly compared with control group. The flow cytometry and MTT results showed that Hela and Siha cells apoptosis rates and cell viabilities were 19.4 ± 2.90%, 25.7 ± 3.92% as well as 86.7 ± 3.12%, 84.16 ± 2.67% respectively 48 h after transfection (P < 0.01). Furthermore, the promoter methylation of five tumor suppressor genes was decreased with the increased mRNA expression after silencing DNMT1, whereas there were no significant changes in PTEN and FHIT genes in Hela cells, and CHFR and FHIT genes in Siha cells. CONCLUSIONS: Our experimental results demonstrate that methylation status of DNMT1 can influence several important tumor suppressor genes activity in cervical tumorigenesis and may have the potential to become an effective target for treatment of cervical cancer.

Activation of mitochondrial ATP-sensitive potassium channels improves rotenone-related motor and neurochemical alterations in rats.

Our previous studies revealed that activation of mitochondrial ATP-sensitive potassium channels exerted protective effects on rotenone-treated rats and cultured cells. The aim of the present study is to examine the potential therapeutic effects of iptakalim, an ATP-sensitive potassium-channel opener, and diazoxide, a selective mitochondrial ATP-sensitive potassium-channel opener, on Parkinsonian symptoms in rats induced by rotenone. Rats were treated with rotenone (2.5 mg/kg s.c.) daily for 4 wk. This treatment caused a depletion of dopamine in the striatum and substantia nigra. Behaviourally, rotenone-infused rats exhibit Parkinsonian symptoms. Catalepsy was estimated by a 9-cm bar test. Treatment with L-dopa (10 mg/kg.d p.o.), iptakalim (0.75, 1.5, 3.0 mg/kg.d p.o.) and diazoxide (3.0 mg/kg.d p.o.) for 2 wk improved behavioural dysfunction and elevated dopamine contents in the striatum and substantia nigra of rotenone-treated rats. Studies also found that iptakalim and diazoxide could reduce the enzymic activities and mRNA levels of inducible nitric oxide synthase elicited by chronic administration of rotenone. All neurorestorative effects by both iptakalim and diazoxide were abolished by 5-hydroxydecanoate, a selective mitochondrial ATP-sensitive potassium-channel blocker. Collectively, the data suggested that mitochondrial ATP-sensitive potassium channels play a key role in improving both Parkinsonian symptoms and neurochemistry alterations of rotenone model rats, and selective activation of mitochondrial ATP-sensitive potassium channels may provide a new therapeutic strategy for treatment of early Parkinson's disease.

Effects of systemic administration of iptakalim on extracellular neurotransmitter levels in the striatum of unilateral 6-hydroxydopamine-lesioned rats.

The function of ATP-sensitive potassium (KATP) channels in nigrostriatal pathway in Parkinson's disease (PD) was studied by employing a novel KATP channel opener iptakalim (Ipt). Apomorphine-induced rotation behavior test and microdialysis experiment were carried out in unilateral 6-hydroxydopamine (6-OHDA) lesioned rats. Behavior test showed that systemic administration of Ipt failed to significantly alleviate apomorphine-induced rotation in unilateral 6-OHDA-lesioned PD model rats. However, using in vivo microdialysis in this PD model rats, it was found that Ipt could increase extracellular dopamine levels in the lesioned side of the striatum and decrease dopamine levels in the intact side of the striatum. Meanwhile, Ipt had no influence on glutamate levels in the intact side, but it did decrease glutamate levels in the lesioned side of the striatum of PD rats. Additionally, in primary cultured rat astrocytes, 6-OHDA decreased overall glutamate uptake activity, but this decrease was recovered and glutamate uptake activity was restored by the opening of KATP channels induced by Ipt and pinacidil. The classical KATP channel blocker glibenclamide completely abolished the effects of Ipt and pinacidil. The present study suggests that (i) the function of KATP channels in the lesioned and intact nigrostriatal pathway is different in unilateral 6-OHDA-lesioned PD model rats. (ii) KATP channels regulate extracellular neurotransmitter levels in the striatum of unilateral 6-OHDA-lesioned rats and may play neuroprotective roles due to their effects on glutamate transporters.

ATP-sensitive potassium channel opener iptakalim protected against the cytotoxicity of MPP+ on SH-SY5Y cells by decreasing extracellular glutamate level.

Mounting evidence reveals that ATP-sensitive potassium (K(ATP)) channel openers (KCOs) exert significant neuroprotection in vivo and in vitro in several models of Parkinson's disease (PD). However, the mechanisms are not well understood. In this study, we demonstrated that SH-SY5Y cells expressed mRNA and proteins for Kir6.1, Kir6.2, SUR1 and SUR2 subunits of K(ATP) channels. Moreover, our results showed that 1-methyl-4-phenyl-pyridinium ion (MPP+) induced up-regulation of mRNA for the Kir6.2 subunit and down-regulation of SUR1. It was further found that pretreatment with iptakalim, a novel K(ATP) channel opener, could attenuate increased extracellular glutamate level and decreased cell survival in SH-SY5Y cell culture after exposure to MPP+. Trans-pyrrolidine-2, 4-dicarboxylic acid (t-PDC), a glutamate transporter inhibitor, partially blocked the effect of iptakalim decreasing extracellular glutamate level. Additionally, iptakalim prevented MPP+-induced inhibition of glutamate uptake in primary cultured astrocytes. The beneficial effects of iptakalim on glutamate uptake of astrocytes were abolished by selective mitochondrial K(ATP) (mitoK(ATP)) channel blocker 5-HD. These results suggest (i) K(ATP) channel dysfunction may be involved in the mechanisms of MPP+-induced cytotoxicity and (ii) iptakalim may modulate glutamate transporters and subsequently alleviate the increase of extracellular glutamate levels induced by MPP+ through opening mitoK(ATP) channels, thereby protecting SH-SY5Y cells against MPP+-induced cytotoxicity.

Systematic administration of iptakalim, an ATP-sensitive potassium channel opener, prevents rotenone-induced motor and neurochemical alterations in rats.

Our previous studies revealed that iptakalim, a novel ATP-sensitive potassium channel opener, has a significant neuroprotective function against ischemia in vivo or rotenone-induced neurotoxicity in vitro. To investigate the potential pharmaceutical benefit of ATP-sensitive potassium channel openers on neurodegenerative diseases, we studied the effects of iptakalim and diazoxide, a selective mitochondrial ATP-sensitive potassium channel opener, on the rotenone-induced nigrostriatal degeneration in rats. Iptakalim (1.5 mg/kg/day, orally) or diazoxide (1.5 mg/kg/day, orally) alone was administered to rats for 3 days, and then for 4 weeks was used daily with an injection of rotenone (2.5 mg/kg/day, subcutaneously) 1 hr later each time. The results showed that rotenone-infused rats exhibited parkinsonian symptoms and had dopamine depletion in the striatum and substantia nigra. Pretreatment with iptakalim or diazoxide prevented rotenone-induced catalepsy and the reduction of striatum dopamine contents. Moreover, iptakalim and diazoxide reduced the enzymatic activities and mRNA levels of inducible nitric oxide synthase elicited by chronic administration of rotenone. These neuroprotective effects of iptakalim and diazoxide were abolished by 5-hydroxydecanoate, a selective mitochondrial ATP-sensitive potassium channel blocker. In conclusion, our data suggested that mitochondrial ATP-sensitive potassium channels might play a key role in preventing both parkinsonian symptoms and neurochemistry alterations induced by rotenone in rats. The selective activation of mitochondrial ATP-sensitive potassium channels may provide a new therapeutic strategy for prevention and treatment of neurodegenerative disorders such as Parkinson's disease.