Low Co-Cultivation Temperature at 20°C Resulted in the Reproducible Maximum Increase in Both the Fresh Weight Yield and Stable Expression of GUS Activity after <i>Agrobacterium tumefaciens</i>-Mediated Transformation of Tobacco Leaf Disks

The importance of controlled temperature during the four-days co-cultivation period was evaluated under the most physiologically relevant conditions for Agrobacterium tumefaciens-mediated transformation of tobacco (Nicotiana tabacum L. cv. Xanthi (nn, Smith)) leaf disks. We compared the effect of temperatures ranging from 15°C, 18°C, 20°C, 22°C to 25°C on the stable expression of β-glucuronidase (GUS) activity of 14 days old hygromycin-selected leaf disks, and on the increase in the fresh weight yield of 28 days old kanamycin-selected calli. The highest average of GUS activity was obtained at 20°C among the five temperatures tested although the difference between the 18°C and 20°C treatment was not statistically significant. The GUS activity at 15°C was statistically lower than those at 18°C and 20°C. The GUS activity in 22°C treatment was an intermediate between the highest (18/20°C) and second highest averages (15°C), and was not statistically significantly different. The lowest average of GUS activity was observed at 25°C. The highest increase in the plate average of fresh weight yield was obtained at 20°C among the five temperature tested. The 20°C treatment was statistically significantly better than the 15°C and 18°C treatments. The 20°C co-cultivation treatment resulted in the higher FW yield than 22°C and 25°C even though the differences were not statistically significant. In conclusion, low co-cultivation temperature at 20°C resulted in the reproducible maximum increase in both the fresh weight yield and stable expression of GUS activity after transformation of tobacco leaf disks.

兼业视角下农户对天气指数保险的支付意愿研究——基于湖北荆州和潜江稻虾共作农户的调研数据

支付意愿反映的保险需求对农业保险发展具有重要影响。基于湖北省实地调研的229份农户问卷,建立Logistic模型,探讨影响农户支付意愿的因素,并运用条件估值法测算农户的平均支付意愿。结果表明,纯农户对天气指数保险的支付意愿强于兼业户,支付意愿与其受教育年限、种养规模、气象灾害发生频率、气象灾害影响程度、是否买过保险、农业保险保障能力有关。在1500元/667 m^(2)的保额下,农户的平均支付意愿为37.72元/667 m^(2),远低于90元/667 m^(2)的无补贴厘定保费。

School-Enterprise Cooperation in Excellent Engineer Education and Training Program at UESTC

School of Information and Software Engineering at University of Electronic Science and Technology of China(abbreviated hereafter as "SISE") joined Excellent Engineer Education and Training Program launched by Ministry of Education of China in 2011. This paper discussed nine models of school-enterprise cooperation practiced at SISE since 2011. The school-enterprise cooperation model effectively broadens the students' horizons and improves the students' practical ability and has been recognized by academic circles.

Enhanced methane production in an anaerobic digestion and microbial electrolysis cell coupled system with co-cultivation of Geobacter and Methanosarcina

The anaerobic digestion（AD）and microbial electrolysis cell（MEC）coupled system has been proved to be a promising process for biomethane production.In this paper,it was found that by co-cultivating Geobacter with Methanosarcina in an AD–MEC coupled system,methane yield was further increased by 24.1%,achieving to 360.2 m L/g-COD,which was comparable to the theoretical methane yield of an anaerobic digester.With the presence of Geobacter,the maximum chemical oxygen demand（COD）removal rate（216.8 mg COD/（L·hr））and current density（304.3 A/m3）were both increased by 1.3 and 1.8 fold compared to the previous study without Geobacter,resulting in overall energy efficiency reaching up to 74.6%.Community analysis demonstrated that Geobacter and Methanosarcina could coexist together in the biofilm,and the electrochemical activities of both were confirmed by cyclic voltammetry.Our study observed that the carbon dioxide content in total gas generated from the AD reactor with Geobacter was only half of that generated from the same reactor without Geobacter,suggesting that Methanosarcina may obtain the electron transferred from Geobacter for the reduction of carbon dioxide to methane.Taken together,Geobacter not only can improve the performance of the MEC system,but also can enhance methane production.

Potential one-step strategy for PET degradation and PHB biosynthesis through co-cultivation of two engineered microorganisms

The management and recycling of plastic waste is a challenging global issue.Polyethylene terephthalate(PET),one of the most widely used synthetic plastics,can be hydrolyzed by a series of enzymes.However,upcycling the resulting monomers is also a problem.In this study,we designed a co-cultivation system,in which PET degradation was coupled with polyhydroxybutyrate(PHB)production.First,PETase from Ideonalla sakaiensis was expressed in Yarrowia lipolytica Po1f with a signal peptide from lipase.The engineered PETase-producing Y.lipolytica was confirmed to hydrolyze bis(2-hydroxyethyl)terephthalate(BHET)and PET powder into the monomers terephthalate(TPA)and ethylene glycol(EG).Simultaneously,a TPA-degrading Pseudomonas stutzeri strain isolated from PET waste was transformed with a recombinant plasmid containing the phb CAB operon from Ralstonia eutropha,which encodes enzymes for the biosynthesis of PHB.The two co-cultivated engineered microbes could directly hydrolyze BHET to produce the bioplastic PHB in one fermentation step.During this process,5.16 g/L BHET was hydrolyzed in 12 h,and 3.66 wt%PHB(3.54 g/L cell dry weight)accumulated in 54 h.A total of 0.31g/L TPA was produced from the hydrolyzation of PET in 228 h.Although PHB could not be synthesized directly from PET because of the low hydrolyzing efficiency of PETase,this study provides a new strategy for the biodegradation and upcycling of PET waste by artificial microflora.

Effect of zinc substitution in hydroxyapatite coating on osteoblast and osteoclast differentiation under osteoblast/osteoclast co-culture

Zinc is an essential trace element required for bone remodelling process,but its role in such process remains to be elucidated.In particular,inconsistent results have been reported on the effect of Zn on osteoclastic responses,and supplement of receptor activator of nuclear factor kappa-B ligand(RANKL)factors has been commonly adopted.Co-culture is a suitable approach to elucidating the role of Zn in bone remodelling process,by better imitating the cellular environment as the presence of osteoblasts plays critical role in modulating osteoclastic functions.In this study,zincsubstituted HA coatings have been deposited using a liquid precursor plasma spraying process at two different concentrations(1,2 wt.%).The effect of zinc substitution on osteoblastic and osteoclastic differentiation has been studied in vitro.In particular,a cultivation regime was designed to first induce osteoblastic differentiation of rat bone marrow stromal cells(BMSCs)for 14 days,and then induce osteoclastic differentiation of osteoclast-like precursor RAW 264.7 cells through the aid of the osteoblasts formed for additional 14 days,in the absence of the external addition of RANKL.The results showed that Zn substitution moderately promoted the BMSC differentiation into the osteoblasts and reduced the osteoclastic activity in early time(1 day co-culture).However,promotion of the osteoclastic activity were observed at later stages,as indicated by the significantly enhanced expressions of trap5b and IL-1(8-and 15-day co-culture)and moderate stimulation of the nucleus integration and formation of the multinucleated cells(14-day co-culture).Such stimulating effect of the osteoclastic activity was absent under mono-culture of RAW 264.7 cell,with simple RANKL supplementation.The results suggest that both the zinc and the presence of MSC/osteoblast play profound and highly interacted roles on osteoclast differentiation and activity,which is critical in modulating the bone remodelling process.

Viability of combining microalgae and macroalgae cultures for treating anaerobically digested piggery effluent

Algal phytoremediation represents a practical green solution for treating anaerobically digested piggery effluent(ADPE). The potential and viability of combining microalgae and macroalgae cultivation for the efficient treatment of ADPE were evaluated in this study.Bioprospecting the ability of different locally isolated macroalgae species illustrated the potential of Cladophora sp. to successfully grow and treat ADPE with up to 150 mg/L NH_4^+ with a biomass productivity of(0.13 ± 0.02) g/(L·day) and ammonium removal rate of(10.23 ± 0.18) mg/(L·day) NH_4^+. When grown by itself, the microalgae consortium used in this study consisting of Chlorella sp. and Scenedesmus sp. was found to grow and treat undiluted ADPE(up to 525 mg/L NH_4^+) with an average ammonium removal rate of 25 mg/(L·day) NH_4^+ and biomass productivity of(0.012 ± 0.0001) g/(L·day). Nevertheless, when combined together, despite the different cultivation systems(attached and non-attached) evaluated,microalgae and macroalgae were unable to co-exist together and treat ADPE as their respective growth were inversely related to each other due to direct competition for nutrients and available resources as well as the negative physical interaction between both algal groups.