Abstract:The first transgenic fish was generated in China about 30 years ago. Since then, considerable progress has been achieved for farmed fishes breeding with improvement of target traits of growth, disease resistance, stress tolerance, and nutrition qualities. Up to now, the technology of transgenic fish breeding is almost mature and the biosafety assessment is established. In this review, a successful example of the fast-growing transgenic common carp was presented and the foreground of transgenic fish breeding was also discussed and prospected.

Abstract:The clustered regulatory interspaced short palindromic repeat-Cas9 (CRISPR-Cas9) system is the part of the prokaryotic immune system, which could recognize and delete the exogenous sequences originated from virus or plasmid. Based on its mechanism, CRISPR-Cas9 system was developed into the new generation of gene editing tool. Compared to the existed technologies such as ES targeting, ZFN or TALEN, CRISPR-Cas9 system is a more efficient, economical and promising approach to manipulate the genome. In this review, we summarize the research progress about CRISPR-Cas9 technology, especially the latest applications in gene therapy studies of human diseases.

Abstract:As a member of the sirtuins family, also called Class III histone deacetylases (HDACs), SIRT6 has many catalytic enzyme activities and plays a pivotal role in biological processes including anti-aging, chromatin regulation, transcriptional control, glucose and lipid metabolism, and DNA damage repair. Recently, increasing evidences indicated that SIRT6 was related to initiation and development of tumors, such as hepatic cancer, lung cancer, breast cancer and genital system tumors. However, SIRT6 might play a dual role in tumorigenesis and progression. SIRT6 often acted as a tumor suppressor, but might play an oncogenic role. Based on our current study, we depicted the essential roles of SIRT6 in the initiation and progression of various tumors, and summarized its mode of actions, which might provide clues for cancer therapy.

Abstract:Cellulosic ethanol, with the advantages of renewable resource, cleanliness and safety, is the mainstream of new energy development and has obtained extensive attention worldwide. In this review, the biological characteristics of beets were introduced, and then the superiority and application progress of beets and its by-product sugar beet pulp in the bioethanol production were stated. At last, cellulosic ethanol production coupled with the component separation and comprehensive utilization of beet pulp was proposed.

Abstract:For further research of the apoptosis mechanism of Schistosoma japonicum (S. japonicum). The cDNA encoding Sjcaspase3 of Schistosoma japonicum was amplified by polymerase chain reaction (PCR) technique, which contained 900 nucleotides and encoded 299 amino acids. The theory molecular weight and isoelectric point (PI) of the deduced protein is 33.5 kDa and 6.39, respectively. Real-time PCR was used to analyze the transcription profiles of Sjcaspase3 at different development stages of S. japonicum. The results showed that this gene was expressed in all stages of S. japonicum with the highest expression in 21d worms, and the level of gene transcription in 42 d female worms was higher than that of male worms. The recombinant plasmid pXJ40-FLAG-Sjcaspase3 was constructed and transfection into Hela cells successfully. Real-time PCR and Western blotting analysis showed Sjcaspase3 was successfully expressed in Hela cells. Enzyme activity analysis revealed that recombinant Sjcaspase3 possessed the activity to cut substrate DEVD. Flow cytometry proved that Sjcaspase3 could induce early apoptosis of Hela cells. The results provide the basis for proceeding further study on the biological function of Sjcaspase3 and better understand the apoptosis mechanism of S. japonicum.

Abstract:Chromosomal integration of heterologous genes or pathways is preferred over the use of episomal plasmids for its inherently stability and thus more desirable in the industrial setting. However, the position of integration of heterologous genes in the genome influences the expression levels. In combination of high throughput transformation of the Yeast Knock-out Collection (YKO) and FACS analysis, the position effect on heterologous reporter gene gfp was identified across the whole genome in yeast. In total 428 high-expressed sites and 444 low-expressed sites were spotted, providing massive data to analyze patterns and reasons for region dependency of gene expression on the genome-wide scale.

Abstract:Production of chiral amines and unnatural amino-acid using ω-transaminase can be achieved by kinetic resolution and asymmetric synthesis, thus ω-transaminase is of great importance in the synthesis of pharmaceutical intermediates. By genomic data mining, a putative ω-transaminase gene hbp was found in Burkholderia phytofirmans PsJN. The gene was cloned and over-expressed in Escherichia coli BL21 (DE3). The recombinant enzyme (HBP) was purified by Ni-NTA column and its catalytic properties and substrate profile were studied. HBP showed high relative activity (32.47 U/mg) and enantioselectivity toward β-phenylalanine (β-Phe). The optimal reaction temperature and pH were 40 ℃ and 8.0–8.5, respectively. We also established a simpler and more effective method to detect the deamination reaction of β-Phe by UV absorption method using microplate reader, and demonstrated the thermodynamic property of this reaction. The substrate profiling showed that HBP was specific to β-Phe and its derivatives as the amino donor. HBP catalyzed the resolution of rac-β-Phe and its derivatives, the products (R)-amino acids were obtained with about 50% conversions and 99% ee.

Abstract:Glutathione S-transferase (GST) is important in plants to resist various stresses. In this study, two Phi GST genes (SmGSTF1 and SmGSTF2) were cloned from Selaginella moellendorffii. SmGSTF1 and SmGSTF2 genes encode proteins of 215 amino acid residues. Gene expression analysis showed that the two genes were expressed in roots, stems and leaves. The recombinant SmGSTF1 and SmGSTF2 proteins were overexpressed in Escherichia coli, and purified by Ni-affinity chromatography. SmGSTF1 and SmGSTF2 had the catalytic activity towards 1-Chloro-2,4-Dieitrobenzene, 4-Chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl), and 4-Nitrobenzyl chloride substrates. SmGSTF1 also had the activity towards Fluorodifen and Cumyl hydroperoxide (Cum-OOH), whereas SmGSTF2 not. The enzyme kinetics analysis showed that SmGSTF1 and SmGSTF2 had high affinity towards glutathione, and low affinity towards 1-Chloro-2, 4-Dieitrobenzene. The enzymatic activity of SmGSTF1 and SmGSTF2 had high catalytic activity between pH 7 and 8.5, and between 45 and 55 °C. SmGSTF1 and SmGSTF2 may have an important role in the resistance of Selaginella moellendorfii against stress.

Abstract:Reversible phosphorylation plays a crucial role in regulating protein activities and functions. Sexual reproduction directly affects yield of most agricultural crops. As the male reproductive organ, anther generates microspores (pollen), delivering gametes (sperms) to complete double fertilization in higher plants. Here, we took the advantage of Nano UHPLC-MS/MS to analyze maize (Zea mays, B73) early anthers at proteomic and phosphoproteomic levels, to explore the protein and phosphorylation modification regulatory networks controlling maize anther development. Our proteomic analysis identified 3 016 unique peptides, belonging to 1 032 maize proteins. MapMan analysis revealed variously potential proteins associated with maize anther development, such as receptor-like kinases (GRMZM2G082823_P01 and GRMZM5G805485_P01). Using phospho-peptides enriched by TiO2 affinity chromatography, our phosphoproteomic analysis detected 257 phospho-peptides from 210 phosphoproteins, discovering 223 phosphosites. Compared to the 86 maize phosphoproteins collected in the Plant Protein Phosphorylation Data Base (P3DB), we found that 203 phosphoproteins and 218 phosphosites were not revealed before. Further bioinformatics analysis revealed that phosphorylation of 14-3-3 proteins, kinases, phosphatases, transcription factors, cell cycle and chromatin structure related proteins might play important roles in regulating normal anther development in maize. Our findings not only enlarged the maize phosphoproteome data, but also provided information for analyzing the molecular mechanism controlling maize anther development at genetic and biochemical levels.

Abstract:For more economical and efficient DNA clonging, pFL-XS-T, a Biobrick-T vector was constructed based on pMD18-T vector, carrying clonging regions of XbaⅠ-XcmⅠ-XcmⅠ-SpeⅠ. The results revealed that PCR products could be conveniently inserted into pFL-XS-T vevtor digested by XcmⅠby means of TA cloning. The positive frequency of recombination can meet the experimental requirements and all the plasmids obtained meet Biobrick standard. Moreover, the pFL-XS-T is compatible with other Biobrick parts, and serves as a vector for functional DNA fragments screening.

Abstract:RNA-binding protein exerts important biological function by specifically recognizing RNA motif. SELEX (Systematic evolution of ligands by exponential enrichment), an in vitro selection method, can obtain consensus motif with high-affinity and specificity for many target molecules from DNA or RNA libraries. Here, we combined SELEX with next-generation sequencing to study the protein-RNA interaction in vitro. A pool of RNAs with 20 bp random sequences were transcribed by T7 promoter, and target protein was inserted into plasmid containing SBP-tag, which can be captured by streptavidin beads. Through only one cycle, the specific RNA motif can be obtained, which dramatically improved the selection efficiency. Using this method, we found that human hnRNP A1 RRMs domain (UP1 domain) bound RNA motifs containing AGG and AG sequences. The EMSA experiment indicated that hnRNP A1 RRMs could bind the obtained RNA motif. Taken together, this method provides a rapid and effective method to study the RNA binding specificity of proteins.

Abstract:With the advancements of stem cells and regenerative medicine, interspecies chimera has become a hot topic and will pave a new way of providing donor sources in organ transplantation. However, the interspecies chimera is confronted with a number of scientific questions and technical obstacles, including selections of appropriate embryonic stage and appropriate culture medium; those factors will deeply influence the developmental balance between donor cells and receptor embryos. Due to its relatively rapid reproductive cycle and similar organ size to human’s, porcine is a very potential donor candidate to study these questions. To compare the development and chimeric efficiency of interspecies embryos, we tested and evaluated three different culture systems, PZM-3 (Porcine zygotic medium), culture medium for iPSCs (N2B27) and 3.5 h of N2B27 before PZM-3 (N2B27(3.5 h)), and two different embryonic stages, 8-cell and blastocyst in mouse-porcine chimeric embryos using parthenogenetically activated porcine embryos and mouse induced pluripotent stem cells (miPS). The results showed that, PZM-3 was beneficial for both development of chimeric embryos and miPSCs proliferation in porcine embryos in the 8-cell injection group. After early blastocyst injection, the chimeric efficiency did not appear significantly different among the three culture systems but was lower than 8-cell injection. In summary, the results suggest that 8-cell injection and PZM-3 culture medium are more beneficial to the in vitro development and chimeric efficiency of mouse-porcine chimeric embryos.

Abstract:To enhance the production of glucose oxidase by recombinant Pichia pastoris, two strategies were developed, which were namely co-feeding of methanol and sorbitol and co-expressing of the protein disulfide isomerase (PDI) and Vitreoscialla hemoglobin (VHb). The volumetric activity reached 456 U/mL by using the strain X33/pPIC9k-GOD, in 5 liter fermentator, with the co-feeding of methanol and sorbitol, it was 0.2 fold higher than that only feeding by methanol. The improved strain was obtained by co-expressing PDI-VHb with GOD. While fermented in a 5 liter fermentator by feeding methanol and sorbitol, the activity of the improved strain reached 716 U/mL with a yield of 7 400 mg/L total soluble protein concentration. These results indicated that heterologous protein expression level can be enhanced by optimizing fermentation condition and co-expression molecular chaperon in Pichia pastoris.

Abstract:Nucleases is an important enzyme widely used in biotechnology. A codon optimized nuclease gene (SNU) from Northern Shrimps was inserted into pPICZα A vector, and expressed extracellularly in strain SMD1168H. On the basis of multi-copy recombinant strain, we further optimized the expression condition and characterized SNU. SNU was highly expressed and stable after 1% methanol induction for 72 h, yield reached 1.4×105 U/mL. SDS-PAGE electrophoresis demonstrated that this is a N-linked glycoprotein of 50 kDa. It was purified by one step DEAE Sephadex chromatography to the purity of about 15 mg/L with a specific activity of 6.291×106 U/mg. Functional analysis on the nuclease activity indicated that it was stimulated by bivalent iron, such as Ca2+, Mn2+, Co2+ and Mg2+, but inhibited by Zn2+, Cu2+ and high salt. Meanwhile, it was irreversibly inactivated at 70 ℃ for 10 min.