Abstract:Neuropeptides are an important class of endogenous bioactive substances involved in the function of the nervous system, and connect the brain and other neural and peripheral organs. Mass spectrometry-based neuropeptidomics are designed to study neuropeptides in a large-scale manner and obtain important molecular information to further understand the mechanism of nervous system regulation and the pathogenesis of neurological diseases. This review summarizes the basic strategies for the study of neuropeptides using mass spectrometry, including sample preparation and processing, qualitative and quantitative methods, and mass spectrometry imagining.

Abstract:Cardiac regenerative therapy has attracted much attention as a novel approach for heart diseases. Direct reprogramming of fibroblasts into cardiomyocytes without going through a pluripotent stem cell stage would provide a promising source of cells for cell transplantation in future. This review summarizes the research methods and problems of direct reprogramming of fibroblasts into cardiomyocytes in vitro and in vivo, and forecasts the future development of this new strategy.

Abstract:Rotaviruses are leading causes of worldwide acute diarrhea in children younger than 5 years old, with severe consequence of social and economic burden. Vaccination is the most effective way to control rotavirus infection, however, the licensed rotavirus vaccines are ineffective in some low-income countries of Africa and Asia, where the mortality caused by rotavirus is higher than other areas. In addition, there are also safety concerns such as increased risk of intussusception. Therefore, it is urgent to improve the efficiency and safety of rotavirus vaccine to reduce the morbidity and mortality caused by rotavirus. Till now, many efforts are made to improve the effectiveness of rotavirus vaccines, and the inactive vaccine becomes the main trend in the research of rotavirus vaccine. The developments in recombinant rotavirus vaccines, especially in VP4 subunit vaccines are summarized in this review, and it could be helpful to develop effective recombinant rotavirus vaccines in further studies.

Abstract:Camelidae can produce a unique antibody that lacks light chain called variable heavy chain domain, also known as nanobodies. This antibody contains only one variable region, with high affinity, high stability, strong tissue penetration, efficient expression. Besides, their toxicity and immunogenicity are both low to be used for both therapeutic and diagnostic applications, as well as research tools. In this review, we discuss how nanobody has been explored as therapeutics in oncology, and provide ideas for the further development of nanobody.

Abstract:Terminators as regulatory signals are typically placed behind the last coding sequence to block the transcription of DNA to RNA and release the transcript. In the present study, the hairpin and the U-rich sequence of the bacteriophage λto terminator were first modified to study their effects on termination efficiency and mRNA stability in Bacillus subtilis 168. Compared with the native λto terminator, the terminator variants M3, M11 and M12 showed higher termination efficiency values. Moreover, the variantsM3, M4 and M11 showed significant positive effects on the mRNA stability of the upstream gfp gene. Additionally, insertion of RNase site also increased the mRNA stability. The results of this study suggested that the composition of the hairpin loop is not required for effective intrinsic termination in B. subtilis. Our results also showed that the terminator could also be used as a potential tool for increasing mRNA stability and the corresponding enzyme production in B. subtilis.

Abstract:With basal medium, we studied the growth status, lipid droplet distribution, total lipid content of Chlorella protothecoides CS-41 treated with different concentrations of sodium chloride (0, 150, 300 and 600 mmol/L) by optical microscopy, electron microscopy, confocal laser focusing and Nile red staining. Results show that the addition of NaCl affected the growth of Chlorella protothecoides CS-41. With the increase of NaCl concentration, the growth rate of Chlorella was inhibited. Chlorella cell wall became thicker, and lipid droplets increased. At the early stage, the amount of lipid droplets in the 600 mmol/L NaCl culture was the highest, but at the late-log stage, the amount of lipid droplets increased with the increase of the biomass of culture in 150 and 300 mmol/L NaCl culture. At the stable stage, biomass (dry weight) in 300 mmol/L NaCl culture was 73.55% of that in the control, but the total lipid content was 2.22 times higher than that in the control. A certain concentration of sodium chloride treatment can significantly increase the lipid content of Chlorella protothecoides CS-41.

Abstract:Arginine kinase (AK) is a key enzyme in energy metabolism of invertebrates and plays an important regulatory role in the life activities such as growth and development, nutrition utilization, immune resistance and stress response. Arginine kinase of Bombyx mori (BmAK) is related to the energy balance and anti-NPV process, but there is little research on its molecular structure and enzymatic properties. We cloned the ORF sequence of BmAK gene, and analyzed chromosomal localization, genomic structure, mRNA structure, secondary and tertiary structure. Phylogenetic analysis indicated that AK was highly conserved in evolution. Soluble recombinant BmAK was obtained by prokaryotic expression, and purified by Ni-NTA affinity chromatography. The circular dichroism spectroscopy showed that BmAK contained α-helix structures, and its α-helix structures were relatively stable in the pH range between 5 and 10. Enzyme activity analysis showed that the optimum temperature of BmAK was 30 ℃ and the optimum pH of BmAK was 7.5. The optimal temperature of BmAK was 25 ℃. Between 15 ℃ and 30 ℃, the structure and activity of BmAK was relatively stable. The structure of BmAK was relatively stable at pH 7.0. Our findings reveal the structure and function of BmAK to develop novel green safe and environmentally friendly insecticides.

Abstract:Taiwanofungus camphoratus is a valuable and rare medicinal mushroom with various bioactivities, such as liver protection and anti-cancer. T. camphoratus can produce many arthroconidia at the end of submerged fermentation, but molecular mechanism underlying this submerged conidiation remains unknown. In this study, we found that Ca2+ concentration in culture medium significantly affected the arthroconidium production of T. camphoratus. Then, we identified two proteins (CaM and HSP90) involved in Ca2+/calmodulin signaling pathway and one protein (AbaA) involved in FluG-mediated conidiation pathway by two-dimensional electrophoresis analyses. Furthermore, we proposed a Ca2+/calmodulin- and FluG-mediated signaling pathway by bioinformatics analysis. By real-time quantitative PCR analyses of 23 key genes in the Ca2+/calmodulin- and FluG-mediated conidiation pathway, we found that expression levels of 7 genes (crz1, hsp90, flbB, brlA, abaA, wetA and fadA) showed significant responses to Ca2+ concentration in fermentation medium. Our research is beneficial for elucidating the underlying mechanism of submerged fermentation conidiation for T. camphoratus.

Abstract:We constructed recombinant adenoviruses expressing miR-29b2c (Ad-miR29b2c), and analyzed their effects on the proliferation and migration of HGC-27 and MGC-803 cells. miR-29b2c gene was amplified by PCR from genomic DNA and cloned into the pAdTrack-CMV vector to create the shuttle plasmid pAdT-29b2c. The recombinant plasmid was verified by restriction enzyme digestion and sequencing. The linearized shuttle vector was mixed with an adenoviral backbone plasmid (pAdEasy-1), followed by cotransformation into competent BJ5183 cells to generate the recombinant plasmid pAd-miR-29b2c. Finally, recombinant adenoviral vectors were generated by transfecting the recombinant plasmid into 293A packaging cell line. HGC-27 and MGC-803 cells were infected with the recombinant adenoviruses expressing pAd-miR-29b2c, then MTT and wound-healing assay were used to analyze the effects of pAd-miR-29b2c on the proliferation and migration of HGC-27 and MGC-803 cells. The miR-29b and miR-29c levels were significantly increased in HGC-27 cells after infected with pAd-miR-29b2c. MTT and wound-healing analysis also revealed a significant decrease in proliferation and migration of HGC-27 and MGC-803 cells compared to the control Ad-GFP-infected cells. Furthermore, western blotting results demonstrated that the protein expression level of δ-catenin was reduced in pAd-miR-29b2c transfected HGC-27 and MGC-803 cells. Taken together, the recombinant adenoviral vector was generated, and it can significantly inhibit the proliferation and migration of HGC-27 and MGC-803 cells.

Abstract:Unlike cerebrospinal fluid or blood, urine accumulates metabolic changes of the body and has the potential to be a promising source of early biomarkers discovery. Bacterial meningitis is a major cause of illness among neonates and children worldwide. In this study, we used Escherichia coli-injected rat model to mimic meningitis and collected urine samples on day 1 and day 3. We used two different methods to digest proteins and analyzed peptides by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). We identified 17 and 20 differential proteins by two methods respectively on day 1, and 5 differential proteins by filter-aided digestion method on day 3. Finding these differential proteins laid a foundation to further explore biomarkers of bacterial meningitis.

Abstract:To study the effects of different frequency sinusoidal electromagnetic fields on the bone mineral density and bone histomorphometry of SD young rats, and to screen suitable electromagnetic field frequency. In total 32 female SD rats of 8 weeks old were randomly divided into 4 groups: control group, 15 Hz group, 30 Hz group and 45 Hz group. Except for the control group, rats in experimental groups were treated with corresponding frequency of 1.8 mT sinusoidal electromagnetic field 90 minutes every day. Rats were measured for bone mineral density after 8 weeks by dual energy X-ray absorptiometry. Rats’ femur and vertebral bones were measured by analyzing the static and dynamic forms on the right tibia bone for morphometrics. Rat serum was measured to estimate the index of bone formation and bone resorption. Bone mineral density of rats from 15 Hz group and 45 Hz group was higher than that of the control group (P<0.05). Serum osteocalcin level of rats from 15 Hz group and 45 Hz group was higher than that of the control group (P<0.05). Double fluorescence spacing and static parameters of bone tissue in experimental group rat tibia were higher than that of the control group (P<0.05). Our findings imply that 15 Hz and 45 Hz sinusoidal electromagnetic fields can effectively increase bone mineral density in young rats for preventing osteoporosis.

Abstract:Superoxide dismutase (SOD) family is necessary to protect cells from the toxicity of reactive oxygen species produced during normal metabolism. Among SODs, manganese-containing superoxide dismutase (Mn-SOD, SOD2) is the most important one. The DNA fragment containing the full nucleotide of full-length human SOD2 was synthesized and inserted into the prokaryotic expression vector pGEX-4T-1 with tag GST. DNA construct was then transformed into Escherichia coli BL21 (DE3) and expression was induced with IPTG at 25 ℃. The recombinant fusion protein GST-SOD2 (46 kDa) was purified from the bacterial lysate by GST resin column affinity chromatography. GST tag was cleaved with thrombin, and a crude SOD2 recombinant protein (25 kDa) was obtained and further purified by heparin affinity chromatography. Activities of the two SOD2 proteins were 1 788 and 2 000 U/mg, respectively. Both SOD2 proteins were stable under physiological condition and cell-penetrating (P<0.05). Our findings open the possibility to study the structure and effects of two full-length recombinant SOD2 proteins.

Abstract:To improve the yield of insulin precursor (PI), we constructed a recombinant expression vector pPIC9K-PI and transformed it into Pichia pastoris GS115 using electroporation. After screening, a mutant strain CL012 with 12 copies was obtained on the YPDS plate containing 4.0 mg/mL G418. Then, the components of SNAREs (Soluble N-ethylmaleimide-sensitive factor attachment receptor proteins), SNC2 and SNC2-SSO2, were expressed in the strain CL012 to explore the effect of SNAREs on the yield of PI. In shake flask culture, the strains expressing SNC2 and SNC2-SSO2 yielded PI of 1.89 mg/L and 2.21 mg/L after methanol induction for 96 h, which were improved by 23.53% and 44.44% compared to that of strain CL012 (1.53 mg/L), respectively. Further, in a 5-L bioreactor, the yield of PI with strain CL012 was 53 mg/L for high-density fermentation, after 96 h of methanol induction, which was 34.64-fold higher than that of shake culture. The strains expressing SNC2 and SNC2-SSO2 yielded the PI of 64 mg/L and 78 mg/L, which were respectively increased by 20.75% and 47.17%, compared to that of strain CL012. This work indicated that SNAREs components promoted the secretion of PI to improve its heterologous expression in P. pastoris.

Abstract:Molecular cloning is one of the most important and widely used technologies in molecular biology research. Generally, the target DNA fragment and the vector are separately digested by restriction enzyme, then purified and recovered, and then ligated with DNA-ligase. For some very short gene fragments (<300 bp), the recovery efficiency of the purified fragment is very low after digestion and cleavage, leading to the difficulty in its inserting into the expression vector. To address this issue, we developed a cloning method based on restoration of antibiotic resistance in constructing recombinant plasmid, which proved highly efficient in cloning very short gene fragments.

Abstract:In order to improve transformation efficiency of phytosterols into 9α-hydroxylation of 4-androstene-3,17-dione (9α-OH-AD) by Mycobacterium sp. LY-1, we studied the strains breeding using atmospheric and room temperature plasma (ARTP) technology and optimized their conversion process. A high production strain named C33 with a good genetic stability was selected and the product molar yield reached to 15.5%, 34.8% higher than that of original strain with 15 g/L phytosterols. Furthermore, the fermentation medium was optimized through the design of orthogonal experiment. Besides, oil-water bidirectional transformation system was set up to improve the 9α-OH-AD molar yield of mutant strain C33. With adding 12 mL soybean oil to each 1 g phytosterols, the molar yield of 9α-OH-AD reached 47.0%, which increased twice than that of control (15.5%).