Abstract:Monoclonal antibodies (mAbs) contribute a lot to the development of numerous fields in life science as a pivotal tool in modern biological research. Development of the PCR methods and maturation of antibody production have made it possible to generate mAbs from single human B cells by single cell RT-PCR with successional cloning and expression in vitro. Compared to traditional monoclonal antibody technologies, single B cell technologies require relatively fewer cells, which are highly efficient in obtaining specific mAbs in a rapid way with preservation of the natural heavy and light chain pairing. With so many advantages, single B cell technologies have been proved to be an attractive approach for retrieval of naive and antigen-experienced antibody repertoires generated in vivo, design of rationale structure-based vaccine, evaluation and development of basic B cell biology concepts in health and autoimmunity, and prevention of infectious diseases by passive immunization and therapy for disorders. Accordingly, this review introduced recent progresses in the single B cell technologies for generating monoclonal antibodies and applications.

Abstract:High-throughput data supply a basis for the reconstruction of genome-scale metabolic networks, and meanwhile bring challenges to the reconstruction and analysis methods. With the increasing of data quantity, the time-consuming manual reconstruction and analysis are far behind the improvement of models. Therefore, various automatic methods emerge. The automatic reconstruction and analysis have irreplaceable effect in the standardization and programming of reconstruction and analysis methods, as well as largely improving the speed of reconstruction and understanding of the metabolic network. In this review, we introduced the progress of automatic reconstruction and the main analysis tools of genome-scale metabolic network. We further summarized the workflow of automatic reconstruction. The difficulties and perspectives on this research field are also discussed.

Abstract:Jatropha curcas L., has been widely recognized as a potential source of biodiesel. In this review, we presented several aspects about the recent progress in molecular biology of J. curcas. First, molecular markers were used to assess its genetic diversity. Second, large-scale genome, transcriptome and proteome analyses were applied for decoding its molecular network. Third, functional characterization of key genes involved in metabolism and regulation of plant development was performed to breed lines with higher quality or higher resistance. Finally, we discussed the limitation of current progress and then proposed the future molecular biology research on J. curcas.

Abstract:Recent metabolomics research revealed a new ginseng ginsenoside IH901 that is synthesized by intestinal microbial transformation in oral administration of ginseng. IH901 shows various biological activities, including anti-tumor, anti-inflammatory, anti-diabetic, and anti-aging. In recent years, great effort has been made to prepare IH901 by microbial and enzymatic transformation in a large scale. In this paper, we reviewed the biotransformation pathways both in vivo and in vitro and bioactive properties of rare ginsenoside IH901.

Abstract:K5 polysaccharide of high molecular weight (HLW) can be splitted into low molecular weight (LMW) K5 polysaccharide by K5 lyase which can be used as the substrate of partial synthesis low molecular heparin sulfate (HS). To prepare recombinant K5 lyase (Elma) and analyze its biological activity, The gene of Elma was cloned by PCR amplification and was ligated with pET-28a. Then the recombinant expression vector pET-28a-Elma was transformed into Escherichia coli BL21 (DE3). After induction with 0.2 mmol/L IPTG at 16 ℃ for 5 h, Elma was successfully expressed, SDS-PAGE analysis demonstrated that the enzyme constituted more than 30% of the total cell proteins. After Ni2+-NTA affinity and G-75 chromatography, the purity of enzyme was more than 95%. Enzymatic activity was determined according to the change of absorbance at 232 nm per ml of the sample. The reduction of the polysaccharide molecular weight could be detected by PAGE electrophoresis. Elma can partially split HA and HS. Its optimal reatcion temperature is 37 ℃ and the optimal reaction pH is 7.0.

Abstract:The flavonoid-3-O-glucosyltransferas (3GT) is one of the most important enzymes for biosynthesis of plant secondary metabolites. In this paper, the homology analysis and gene special primers design were used. With the methods of mordern molecular biology, the full-length gene of 3GT (GenBank Accession No. JN092127) which was cloned from Saussurea involucrata Kar. et Kir by RT-PCR and RACE. The cDNA sequence of 3GT consisted of 1548 bp open reading frame (ORF) encoding 516 amino acid, the deduced 3GT protein shared 91% and 89% identities with that of Fragaria x ananassa GT6, Manihot esculenta anthocyanidin 3-O-glucosyltransferase. Homology analysis showed that deduced 3GT protein has a glycosyltransferase signature domain PSPG-box. The transcripts of 3GT members were found mainly in leaves and callus. 3GT gene of S. involucrata was under the control of the cauliflower mosaic virus (CaMV) 35S promoter, homologous transformation used an Agrobacterium rihizogenes-mediated transformation system. The results on UV spectrophotometry showed S. involucrata callus after suspension culture that an average of total flavonoids on transgenic callus was 2.06 times higher than non-transgenic callus.

Abstract:To assess the ability of the previously selected human vaginal isolates of Lactobacillus crispatus (L. crispatus) T79-3, T90-1 and Lactobacillus jensenii (L. jensenii) T118-3, T231-1 to inhibit the growth of Staphylococcus aureus and block their adhesion to HeLa cells. The inhibitory bioactive substances produced by these Lactobacillus were also identified. Inhibitory substances interaction tests were carried out by using a streak-diffusion method on agar plates. Three types of interaction were performed to determine the inhibitory effect of Lactobacillus on adhesion of Staphylococcus aureus to HeLa cells: Exclusion Group (Lactobacillus and HeLa followed by pathogens), Competition Group (Lactobacillus, HeLa and pathogens together) and Displacement Group (pathogens and HeLa followed by the addition of Lactobacillus). The number of HeLa cells adhered to Staphylococcus aureus was quantified by bacteria colony counts on LB plate. The results showed that lactic acids produced by the Lactobacillus are the main substances that can inhibit Staphylococcus aureus growth and there is variation among the three types of interaction regarding the inhibitory activity against Staphylococcus aureus. The effects of Lactobacillus on blocking the adhesion to HeLa cells were concentration dependent. All four Lactobacillus isolates displayed the ability to inhibit Staphylococcus aureus growth and block Staphylococcus aureus adherence to HeLa cells. Exclusion Group was the most effective, and T79-3 showed greater capacity to block Staphylococcus aureus adherence compared with the other three isolates. The present study suggests the potential ability of L. crispatus T79-3 as probiotic for the treatment and prevention of urogenital infections in women.

Abstract:The calcium gate encoded by CCH1 and MID1 genes is the main channel for external calcium absorption. As one of the important secondary messengers, the elevation of calcium concentration could activate some pathways to take part in various cell processes. In this study, we used CCH1 and MID1 mutant strains and also constructed their complementary strains to study the effect of drug tolerance and virulence of Candida albicans after CCH1 or MID1 deletion. By drug plate sensitivity assay and the broth microdilution method, we compared the changes between different strains. Moreover, we added calcium channel blocker and inhibitors to analyze the effect of calcium concentration on drug action. After the deletion of CCH1 or MID1 gene, the strain exhibited an obvious sensitivity to FLUC and ITRA, and the drug action was regulated by the calcium concentration. In a mouse model of intravenous infection, we found that attenuated virulence of cch1Δ/Δ or mid1Δ/Δ strain is specifically due to a loss of CCH1 or MID1 gene.

Abstract:In order to quantify the curing effects of phenanthridine on yeast prion, we introduced semi-denaturing agarose gel electrophoresis and fluorescence recovery after photobleaching techniques to quantify the curing effects of phenanthridine on yeast prion at the protein and cellular levels with the [PSI+] yeast strain expressing GFP-Sup35p (NGMC) . The results showed that these two approaches could precisely quantify the curing effects of phenanthridine on [PSI+] cells. After a treatment for 1 through 5 days with phenanthridine, the curing rates of [PSI+] cells were 0%, 0%, 51.7%, 87.5% and 94.4%, respectively. Meanwhile, we quantified the sizes of Sup35p polymers in phenanthridine induced pink phenotype cells. The aggregation status in 1–2 days phenanthridine treated cells were similar to those in [PSI+] cells, while the aggregation status in 3–5 days phenanthridine treated cells were similar to those in [psi-] cells.

Abstract:In order to study the physiological mechanism of exogenous calcium on the toxicity of heavy metal cadmium (Cd) to Wedelia trilobata hairy roots, the effects of Cd alone, and in combination with different concentrations of Ca on growth, contents of soluble protein and malondialdehyde (MDA), activities of superoxide dismutase (SOD) and peroxidase (POD), Cd2+ absorption in W. trilobata hairy roots were investigated. Cd concentrations lower than 50 μmol/L enhanced the growth of hairy roots, while concentrations higher than 100 μmol/L inhibited growth, making the branched roots short and small, and also turning the root tips brown, even black. In comparison with the control (0 μmol/L Cd), the soluble protein content in hairy roots was found to increase when cultured with 10~50 μmol/L Cd, and decrease when exposed to a cadmium concentration higher than 100 μmol/L Cd. In addition, the activities of POD and SOD activity and MDA content were significantly higher than the control. Compared to the control (hairy roots cultured without 10~30 mmol/L Ca), 100 μmol/L Cd or 300 μmol/L Cd in combination with 10~30 mmol/L Ca resulted in increased growth, causing the main root and secondary roots thicker and also an increase in soluble protein content. On the contrary, MDA content and POD and SOD activities decreased. Quantitative analysis by Atomic Absorption Spectrophotometry showed that W. trilobata hairy roots can absorb and adsorb heavy metal Cd in the ionic form of Cd2+. The maximum content of Cd2+ absorbed by the hairy roots was obtained with a concentration 100 μmol/L Cd2+ while that of Cd2+ adsorbed by hairy roots was achieved with a concentration of 300 μmol/L Cd2+. The exogenous addition of 10~30 mmol/L Ca2+ was found to reduce the absorption, adsorption of Cd2+ and the toxicity of Cd significantly. This reduction in toxicity was caused by the reduction in the absorption of Cd and decreasing the lipid peroxidation through regulating the activities of antioxidant enzymes SOD and POD in the hairy roots.

Abstract:Pyrosequencing is a tool based on bioluminescence reaction for real-time analyzing DNA sequences. The sensitivity of pyrosequencing mainly depends on luciferase in reaction mixture. However, the instability of pyrosequencing reagents caused by fragile wild Photinus pyralis luciferase (PpL) in conventional pyrosequencing usually leads to unsatisfied results, which limits the application of pyrosequencing. In order to improve the stability of pyrosequencing reagents, the coding sequences of mutant thermostable Luciola lateralis luciferase (rt-LlL) was synthesized, and inserted into the plasmid of pET28a(+) to express the thermostable rt-LlL with a 6×His-tag in the N terminal. The purified rt-LlL with the molecular mass of 60 kDa was obtained by Ni-affinity chromatography. The specific activity of rt-LlL was determined as 4.29×1010 RLU/mg. Moreover, the thermostability of rt-LlL was investigated, and the results showed that rt-LlL had activity at 50 °C, and remained 90% of activity after incubated at 40 °C for 25 min. Finally, rt-LlL was used to substitute commercial Photinus pyralis luciferase in conventional pyrosequencing reagent to get thermostable pyrosequencing reagent. Comparing with conventional pyrosequencing reagent, the thermostable pyrosequencing reagent is more stable, and it’s activity would not lose when incubated at 37 °C for 1 h. This study laid foundation of establishing reliable and stable pyrosequencing system which would be applied in Point-of-Care Testing.