Accurate non-destructive prediction of peach fruit internal quality and physiological maturity with a single scan using near infrared spectroscopy.

The development of precise and reliable near infrared spectroscopy (NIRS)-based non-destructive tools to assess physicochemical properties of fleshy fruit has been challenging. A novel crop load × fruit developmental stage protocol for multivariate NIRS-based prediction models calibration to non-destructively assess peach internal quality and maturity was followed. Regression statistics of the prediction models highlighted that dry matter content (DMC, R2 = 0.98, RMSEP = 0.41%), soluble solids concentration (SSC, R2 = 0.96, RMSEP = 0.58%) and index of absorbance difference (IAD, R2 = 0.96, RMSEP = 0.08) could be estimated accurately with a single scan during fruit growth and development. Thus, the impact of preharvest factors such as crop load and canopy position on peach quality and maturity was evaluated. Large-scale field validation showed that heavier crop loads reduced peach quality (DMC, SSC) and delayed maturity (IAD) and upper canopy position advanced both mainly in the moderate crop loads. This calibration protocol can enhance NIRS adaptation across tree fruit supply chain.

Construction,expression of I-Ad/IgG2b Fc dimer fusion protein and its identification / 中国免疫学杂志

Objective:To construct I-Ad/IgG2b Fc baculovirus expression vector and express I-Ad/IgG2b Fc dimer fusion protein in Sf9 insect cells.Methods:I-Ad α,I-Ad β and IgG2b Fc gene sequences were amplified from BALB/c mouse lymphocytes by RT-PCR.I-Ad α and I-Ad β were connected with the leucine zipper sequence Fos and Jun respectively by overlapping PCR to form I-Ad α-Fos and I-Ad β-Jun.I-Ad α-Fos and IgG2b Fc fragments were ligated by restriction sites Xba I to form I-Ad α-Fos-IgG2b Fc recombination sequence.I-Ad α-Fos-IgG2b Fc and I-Ad β-Jun fragments were inserted to PPH and PP10,which were the downstream of the promoters in the plasmid pFastBacTMDual,to form pFastBacTMDual+[I-Ad/IgG2b Fc] recombinant plasmids.The constructed vector was identified by PCR,restriction endonuclease and sequencing.The recombinant plasmids pFastBacTMDual+[I-Ad/IgG2b Fc] was transferred into the DH10Bac competent cell to form recombinant baculovirus Bacmid+[I-Ad/IgG2b Fc].The recombinant baculovirus was transfected into Sf9 insect cells by liposome transfection reagent.After infected with Sf9 insect cells,the supernatant was collected and concentrated by PEG20000 to obtain I-Ad/IgG2b Fc dimer fusion protein.The fusion protein was detected by double-antibody sandwich ELISA and Western blot.Results:PCR,restriction enzyme digestion and sequencing confirmed that the recombinant vector pFastBacTMDual+[I-Ad/IgG2b Fc] had the correct sequence.The double antibody sandwich ELISA and Western blot showed that recombinant bacmid could successfully infect Sf9 insect cells,and the expressed fusion protein had the correct conformation.Conclusion:The pFastBacTMDual+[I-Ad/IgG2b Fc] baculovirus expression vector was successfully constructed and expressed in Sf9 insect cells,laying a foundation for the study of I-Ad-restricted T cells.

Construction of pIRES-I-A~d?? and stable expression of BALB/c mouse I-A~d?? chain genes in NIH3T3 cell line / 中国免疫学杂志

Objective:To construct pIRES-I-Ad?? bicistronic eukaryotic expression vector. Methods: Total RNA was acquired by TRIZOL method, the genes of I-Ad ?? chains were amplified through RT-PCR, respectively. The target genes were connected to pGEM-T vector and sequenced. Then the target genes were subcloned into pIRES bicistronic eukaiyotic expression vector and NIH3T3 cell line was transfected. Transfectant was screened by G418 antibiotics. Total RNA of transfectant was obtained by TRIZOL method, mRNA of foreign gene was examined by RT-PCR. Flow cytometry( FCM) was used to detennine foreign gene expression in protein level and surface expression in NIH3T3 cell line. Results: Bicistronic eukaryotic expression vector pIRES-I-AdaB was established. Foreign gene in mRNA level in transfectants was examined. Verified Ⅰ-Ad ?? chain wa3 expressed in high level expressed on transfected NIH3T3 cell line surface by FCM. Conclusion:Bicistronic eukaryotic expression vector pIRES-I-Ad ?? was constructed successfully. It is useful for studying antigen presentation and interaction between epitopes and MHC- Ⅱ molecule of BALB/c mouse.