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Tumor is a serious threat to human health. At present, surgical resection, chemoradiotherapy, targeted therapy and immunotherapy are the main therapeutic strategies. Monoclonal antibody has gradually become an indispensable drug type in the clinical treatment of cancer due to its high efficiency and low toxicity. Phage antibody library technology (PALT) is a novel monoclonal antibody preparation technique. The recombinant immunoglobulin variable region of heavy chain (VH)/variable region of light chain (VL) gene is integrated into the phage vector, and the antibody is expressed on the phage surface in the form of fusion protein to obtain a diverse antibody library. Through the process of adsorption-elution-amplification, the antibody library can be screened to obtain the antibody molecule with specific binding antigen as well as its gene sequence. PALT has the advantages of short antibody production cycle, strong plasticity of antibody structure, large antibody yield, high diversity and direct production of humanized antibodies. It has been used in screening tumor markers and preparation of antibody drugs for breast cancer, gastric cancer, lung cancer and liver cancer. This article reviews the recent progress and the application of PALT in tumor therapy.

Zearalenone is one of the most widely polluted Fusarium toxins in the world, seriously endangering livestock and human health. Zearalenone hydrolase (ZHD) derived from Clonostachys rosea can effectively degrade zearalenone. However, the high temperature environment in feed processing hampers the application of this enzyme. Structure-based rational design may provide guidance for engineering the thermal stability of enzymes. In this paper, we used the multiple structure alignment (MSTA) to screen the structural flexibility regions of ZHD. Subsequently, a candidate mutation library was constructed by sequence conservation scoring and conformational free energy calculation, from which 9 single point mutations based on residues 136 and 220 were obtained. The experiments showed that the thermal melting temperature ( T m ) of the 9 mutants increased by 0.4-5.6 ℃. The S220R and S220W mutants showed the best thermal stability, the T m of which increased by 5.6 ℃ and 4.0 ℃ compared to that of the wild type. Moreover, the thermal half-inactivation time at 45 ℃ were 15.4 times and 3.1 times longer, and the relative activities were 70.6% and 57.3% of the wild type. Molecular dynamics simulation analysis showed that the interaction force at and around the mutation site was enhanced, contributing to the improved thermal stability of ZHD. The probability of 220-K130 hydrogen bond of the mutants S220R and S220W increased by 37.1% and 19.3%, and the probability of K130-D223 salt bridge increased by 30.1% and 12.5%, respectively. This work demonstrated the feasibility of thermal stability engineering strategy where the structural and sequence alignment as well as free energy calculation of natural enzymes were integrated, and obtained ZHD variants with enhanced thermal stability, which may facilitate the industrial application of ZHD.

Background and objective Currently, there are only limited number of diagnostic tumor markers for non-small-cell lung cancer (NSCLC). The aim of this study is to screen and identify non-small-cell lung cancer associated antigens, by using of cancer sera containing antibodies which react with autologous cellular antigens (tumor-associated antigens TAAs), which can be used in NSCLC early screening or target treatment. Methods Two T7 phage display cDNA libraries were panning against the sera from 24 patients with NSCLC. Then the enriched libraries were screened with the pool of sera from NSCLC patients, the positive clones encoding antigenic genes were obtained after screening, and the nucleotide sequences of positive were identified and analyzed with BLAST software in GenBank. Results After immunoscreen two T7 phage display cDNA libraries with serum from patients with NSCLC, thirty-one positive clones were obtained and sequence results showed they were derive from 15 genes, 12 of 15 genes were homologous to the genes known in GenBank, such as RHOA, ITGB4, and HNRNPA2/B1 et al . The other three genes expressed sequence tags (ESTs) were not found in GenBank. Conclusion Fifteen NSCLC associated antigen genes and three candiated gene were obtained by SEREX from T7 phage display cDNA libraries.

Objective: To identify and verify the interacting protein of α-11 giardin, so as provide the experimental evidence for studies on the α-11 giardin function., Methods: The yeast two-hybrid cDNA library of the Giardia lambia C2 strain and the bait plasmid of α-11 giardin were constructed. All proteins interacting with α-11 giardin were screened using the yeast two-hybrid system. α-11 giardin and all screened potential interacting protein genes were constructed into pBiFc-Vc-155 and pBiFc-Vn-173 plasmids, and co-transfected into the breast cancer cell line MDA-MB-231. The interactions between α-11 giardin and interacting proteins were verified using bimolecular fluorescence complementation (BiFC)., Results: The yeast two-hybrid G. lambia cDNA library which was quantified at 2.715 × 10 7 colony-forming units (CFU) and the bait plasmid containing α-11 giardin gene without an autoactivation activity were constructed. Following two-round positive screening with the yeast two-hybrid system, two potential proteins interacting with α-11 giardin were screened, including eukaryotic translation initiation factor 5A (EIF5A), calmodulin-dependent protein kinase (CAMKL) and nicotinamide adenine dinucleotide phosphate-specific glutamate dehydrogenase (NADP-GDH), hypothetical protein 1 (GL50803_95880), hypothetical protein 2 (GL50803_87261) and a protein from Giardia canis virus. The α-11 giardin and EIF5A genes were transfected into the pBiFc-Vc-155 and pBiFc-Vn-173 plasmids using BiFC, and the recombinant plasmids pBiFc-Vc-155-α-11 and pBiFc-Vn-173-EIF5A were co-tranfected into MDA-MB-231 cells, which displayed green fluorescence under a microscope, indicating the interaction between α-11 giardin and EIF5A protein in cells., Conclusions: The yeast two-hybrid cDNA library of the G. lambia C2 strain has been successfully constructed, and six potential protein interacting with α-11 giardin have been identified, including EIF5A that interacts with α-11 giardin in cells.

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Ultrashort peptides have higher stability, tissue penetrability, biocompatibility, and less immunogenicity, and are widely applied in biology and medicine. GHK (glycyl-l-histidyl-l-lysine) and GQPR (glycyl-l-glutamyl-l-prolyl-l-arginine) can stimulate collagen renewal and inhibit collagen degradation. GHK and GQPR have been used in cosmetic anti-wrinkle skincare and make-up products. The most common approach for ultrashort peptide production is the solid-phase synthesis, which is eco-unfriendly due to heavy usage of organic chemical reagents during the manufacturing process. Here we report a new approach to the production of ultrashort peptides. Recombinant expression of ultrashort peptides is usually unfeasible because of the short amino acid sequences. A vector pET28a-Trxm harboring the thioredoxin gene was first constructed for subsequent fusion expression. The tandem repeats of GHK and GQPR genes were used as the templates for rolling circle amplification (RCA). The RCA reaction was tuned to incorporate noncanonical nucleotides 5-methylcytosine to obtain long DNA fragments. Gene sequences with various lengths were generated through double digestion of Acc65 Ⅰ and Apa Ⅰ. The resulting digestion products were gel recovered by size (from 500 bp to 1 500 bp) and cloned into pET28a-Trxm to obtain the recombinant vector pET28a-Trxm-(TRSP) n . The pET28a-Trxm-(TRSP) n was introduced into E . coli BL21(DE3) to generate a library of Trxm-(TRSP) n sequences with a controlled distribution of lengths. Through double digestion and sequencing, positive clones with tandem repeats n =1, 2, 3, 4, 6, 7, 8, 9 were obtained. Protein expression results showed protein bands with corresponding molecular weight, and the protein expression level decreased as the tandem repeats increased. The expression level of Trxm-(TRSP) 1 achieved 50% of the total protein, while the expression level of Trxm-(TRSP) 2 was 30% of the total protein. The crude extracts from cell pellets were further treated with enterokinase cleavage, and the supernatants containing (TRSP) 1 were collected after ultrafiltration and then subjected to trypsin cleavage. HPLC analysis indicated that the ultrashort peptides GHK and GQPR were successfully obtained through two-step cleavage. This study may facilitate the commercial production of ultrashort peptides.

Current spam filtering algorithms based on artificial immune system consider little about the noise word attack, so an immune-based anti-noise word attack spam filtering model, named AN-WAIS, is proposed in order to solve the problem. The algorithm uses the Mutual Information Difference as the Evaluation function to discard the good word in the spam and the spam word in the normal email during the stage of the generation of the gene library, so that the gene library can better reflect the characteristics of spam emails. Meanwhile, it can guarantee the purity of the gene library through maintaining the discard word table during the stage of the updating of the antibody. Experimental results show that ANWAIS can obtain higher quality antibody and have better classification performance than that of other spam filtering algorithms without considering the noise word attack. [ABSTRACT FROM AUTHOR]

Plasma exosome microRNAs (miRNAs) are closely related with the occurrence, diagnosis, and treatment of cancers. However, the underlying molecular mechanisms remain unclear. We herein investigated the solution for tackling the unspecific amplification of plasma exosome microRNAs from cancer patients during the construction of its cDNA library. For the restriction enzyme digesting method, the primers were degraded by exonuclease T (EXOT) and phi29 DNA polymerase. For the magnetic bead separation method, the templates and primers were separated through the DNA binding beads. The separation effects of magnetic beads were detected by agarose gel electrophoresis and modified polyacrylamide gel electrophoresis. The levels of plasma exosome miRNAs from cancer patients and various primers were assayed by RT-qPCR. The results indicated that the unspecific amplification stemmed from USR5SR. EXOT and phi29 DNA polymerase could degrade USR5SR, but the templates were also degraded simultaneously. Regarding the magnetic bead separation method, the best effect was achieved via precipitation of primer fragments by 9% PEG and precipitation of templates by 15% PEG. In conclusion, the magnetic bead separation method efficiently circumvented the unspecific amplification during the construction of cDNA library, and therefore led to the successful construction of cDNA library from plasma exosome miRNA of cancer patients and 293T cells.

The genomic DNA of H2-producing bacterium Etharioligenens harbinense YUAN -3 was isolated and partially digested by Sau 3 A I. The fragments of 2. 5 -5.0 kb were selected and inserted into BamH I digested plasmid pUC 19. The genomic clone library of strain YUAN -3 was constructed with 9 x 103 recombinants, indicating the coverage of clone library tends to be the theoretical value based on a 4. 6 Mb average chromosome size of Clostridium, closest to Etharioligenens harbinense, 200 colonies were picked stochastically for sequencing and aligned with the database. The results imply that most of the sequences are similar with the hypothetical protein of hydrogen - producing bacterium whose complete genomes are sequenced, among which 49 sequences have the similarity over 70%, including folylpolyglutamate synthetase, DNA topoisomerase, acetyltransferase and so on, and 7 open reading frames (ORFs) of functional proteins or genes can be obtained. [ABSTRACT FROM AUTHOR]

Promoter is an important genetic tool for fine-tuning of gene expression and has been widely used for metabolic engineering. Corynebacterium glutamicum is an important chassis for industrial biotechnology. However, promoter libraries that are applicable to C. glutamicum have been rarely reported, except for a few developed based on synthetic sequences containing random mutations. In this study, we constructed a promoter library based on the native promoter of odhA gene by mutating the -10 region and the bystanders. Using a red fluorescent protein (RFP) as the reporter, 57 promoter mutants were screened by fluorescence imaging technology in a high-throughput manner. These mutants spanned a strength range between 2.4-fold and 19.6-fold improvements of the wild-type promoter. The strongest mutant exhibited a 2.3-fold higher strength than the widely used strong inducible promoter P trc . Sequencing of all 57 mutants revealed that 55 mutants share a 1-4 bases shift (4 bases shift for 68% mutants) of the conserved -10 motif "TANNNT" to the 3' end of the promoter, compared to the wild-type promoter. Conserved T or G bases at different positions were observed for strong, moderate, and weak promoter mutants. Finally, five promoter mutants with different strength were employed to fine-tune the expression of γ-glutamyl kinase (ProB) for L-proline biosynthesis. Increased promoter strength led to enhanced L-proline production and the highest L-proline titer of 6.4 g/L was obtained when a promoter mutant with a 9.8-fold higher strength compared to the wild-type promoter was used for ProB expression. The use of stronger promoter variants did not further improve L-proline production. In conclusion, a promoter library was constructed based on a native C. glutamicum promoter P odhA . The new promoter library should be useful for systems metabolic engineering of C. glutamicum . The strategy of mutating native promoter may also guide the construction of promoter libraries for other microorganisms.

Objective: To construct a cDNA library of Sparganum mansoni and immunoscreen antigen candidates for immunodiagnosis of sparganosis mansoni., Methods: Total RNA was extracted from S. mansoni , and reversely transcribed into cDNA, which was ligated into the phage vector. These recombinant vectors were packaged in vitro to construct the SMART cDNA library of S. mansoni . Then, the cDNA library was immunoscreened with sera from patients with sparganosis mansoni to yield positive clones. The inserted fragments of positive clones were sequenced and subjected to homology analyses, and the structure and functions of the coding proteins were predicted., Results: The SMATR cDNA library of S. mansoni was successfully constructed. The titer of the cDNA library was 6.25 × 10 6 pfu/mL, with a recombinant efficiency of 100%, and the mean length of the inserted fragments in the library was larger than 1 100 bp. A total of 12 positive clones were obtained by immunoscreening, and were categorized into Sm-I (Sm60-1), Sm-II (Sm58-1), Sm-III (Sm20-1) and Sm-IV (Sm22-3), with 1 134, 1 063, 883 bp and 969 bp long inserted fragments. Their coding proteins were highly homologous with the Spirometra erinaceieuropaei antigenic polypeptide, cytoplasmic antigen, ribosomal protein S4-like protein and unnamed protein product, respectively., Conclusions: A SMART cDNA library of S. mansoni has been successfully constructed and 4 categories of positive clones have been identified, which provides a basis for further studies on diagnostic antigens for sparganosis mansoni.

Objective: To screen proteins interacting with ring finger protein 216(RNF216) through yeast two hybrid experiment, and further clarify the role of RNF216 in the pathogenesis of gonadotropin-releasing hormone deficiency., Methods: A recombinant expression vector pGBKT7-RNF216 was constructed and transformed into yeast Y2HGold, which was hybridized with a human cDNA library in order to screen proteins interacting with RNF216. The interaction was verified in yeast Y2HGold., Results: A recombinant expression vector pGBKT7-RNF216 was successfully constructed and expressed in yeast Y2HGold. Filamin B (FLNB) was identified by yeast two hybrid experiment, and their interaction was verified in yeast Y2HGold., Conclusion: An interaction between FLNB and RNF216 was identified through yeast two hybrid experiment. RNF216 may affect the proliferation and migration of GnRH neurons by regulating FLNB or FLNB/FLNA heterodimers.

Directed evolution is a cyclic process that alternates between constructing different genes and screening functional gene variants. It has been widely used in optimization and analysis of DNA sequence, gene function and protein structure. It includes random gene libraries construction, gene expression in suitable hosts and mutant libraries screening. The key to construct gene library is the storage capacity and mutation diversity, to screen is high sensitivity and high throughput. This review discusses the latest advances in directed evolution. These new technologies greatly accelerate and simplify the traditional directional evolution process and promote the development of directed evolution.

Objective To screen the sequence of nanobodies against human CD20, and obtain anti-CD20-human IgG Fc nanobodies with high affinity and specificity. Methods Based on the naive phage display library, 4 rounds of liquid affinity screening were performed using biotinylated CD20 antigen as the target, and positive clones were identified by ELISA. Prokaryotic expression vector CD20-IgG Fc/pCZN1 was constructed and transformed into E.coli Arctic Express, and the expression of the recombinant protein was induced by IPTG at low temperature and purified by Ni column. The purified product was identified by ELISA and Western blot analysis. Results The specific CD20 nanobody showed good repeatability and hydrophilicity. The purity of anti-CD20-human IgG Fc nanobodies was higher than 85%. ELISA indicated that anti-CD20-human IgG Fc nanobodies had high affinity with CD20 antigen, and Western blot analysis demonstrated they could specifically recognize CD20 antigen. Conclusion The sequence of anti-CD20 nanobody was successfully obtained using the naive phage nanobody library. The purified anti-CD20-human IgG Fc nanobody has high affinity and specificity.

Polyphenol oxidase(PPO) is an important antioxidant enzyme in plants. It has the functions of scavenging active oxygen and synthesizing phenols, lignin, and plant protection factors, and can enhance the plant's resistance to stress and resistance to pests and diseases. Our previous research found that Salvia miltiorrhiza PPO gene can positively regulate salvianolic acid B synthesis. In order to further explore the mechanism, a pGBKT7-PPO bait vector was constructed using the cloned S. miltiorrhiza polyphenol oxidase gene(SmPPO, GenBank accession number: KF712274.1), and verified that it had no self-activation and no toxicity. The titer of S. miltiorrhiza cDNA library constructed by our laboratory was 4.75 × 107 cfu·mL~(-1), which met the requirements for library construction. Through yeast two-hybrid test, 22 proteins that could interact with SmPPO were screened. Only yeast PAL1 and TAT interacted with SmPPO through yeast co-transformation verification. Further verification was performed by bimolecular fluorescence complementary detection(BiFC). Only TAT and SmPPO interacted, so it meant that TAT and SmPPO interacted. TAT and SmPPO were truncated according to the domain, respectively. The first 126 amino acids of SmPPO and tyrosine amino transferase(TAT) were obtained to interact on the cell membrane and chloroplast. SmPPO was obtained by subcellular localization test, which was mainly loca-lized on the nucleus and cell membrane; TAT was localized on the cell membrane. Real-time quantitative PCR results showed that the SmPPO gene was mainly expressed in roots and stems; the TAT gene was expressed in roots, and the expression level in stems and flowers was low. This article lays a solid foundation for the in-depth study of the molecular mechanism of the interaction of S. miltiorrhiza SmPPO and TAT to regulate the synthesis of phenolic substances.

Objective: To study the genetic changes and biological potential of proliferative nodule in congenital melanocytic nevus. Methods: Whole-exome sequencing was carried out using the technique of next-generation sequencing (NGS) in order to detect the genomic alterations of two cases of proliferative nodules (PN) in congenital melanocytic nevi (CMN). Twelve cases of CMN and ten cases of malignant melanoma were used as benign and malignant controls, respectively. Mutated genes that possessed statistically significant difference between benign and malignant controls were listed, according to what benign and malignant statuses were classified and clustered. The heatmaps of clustering analyses were depicted using heatmap package. Fluorescence in situ hybridization (FISH) was also used to validate the above results. Results: Eighty-six common somatic gene mutations were detected in two samples of PN. Compared with CMN, PN had 52 more mutated genes. Furthermore, 22 of these 52 mutated genes were also detected in malignant melanoma samples. Two cases of PN fell between benign CMN and malignant melanoma in germline mutation clustering. Both cases of PN were positive in the FISH tests. Conclusions: The genetic changes of PN partially overlap with those of CMN and malignant melanoma. Therefore, although most of the PN manifest as a benign lesion clinically, it may have certain malignant potential at the genetic level, and warrant long-term monitoring and follow-up.

The combination of high-quality mutagenesis and effective screening can improve the efficiency of enzyme directed evolution. In this study, a high efficiency cloning construction method of Multi-points Combinational Mutagenesis (MCM) was developed. Efficient multi-point combination mutations were performed in this MCM method by introducing DNA assembly, fusion PCR and hybridization techniques. After optimization, the efficiency of MCM was tested by directed evolution of benzoylformate decarboxylase. The obtained number of Colony Forming Units (CFUs) by electroporation to competent cells E. coli Trelief™ 5α exceeded 10⁶ CFUs/μg DNA. Test results show that 90/100 clones were precisely assembled. The efficiency of simultaneous mutation at 5 sites (L109, L110, H281, Q282 and A460) was up to 88%. Finally, a mutant enzyme (L109Y, L110D, H281G, Q282V and A460M) with a 10-fold increase in kcat/Km was obtained. Therefore, this method can effectively create diverse mutant libraries and promote the rapid development of enzyme directed evolution.

The CRISPR/Cas9 technology has developed rapidly in recent years with fast, simple and accurate editing functions to allow gene knockout, knock in, activation and interference. It has become a powerful genetic screening tool and been widely used in various models including cell lines, mice and zebrafish. The application of CRISPR system in constructing genome library for high-throughput screening is the main strategy for target gene research of diseases, especially neoplasms. Here we summarize the rationales and recent development of CRISPR/Cas9 library screening technology, the strategies for improving the off-target effects, the basic workflow of library screening and the application of this technology in tumor research.

Objective To screen a standard homogenous cDNA library of human gastric mucosal epithelium with yeast two-hybrid system and find the proteins that interact with Src-homology 2-containing inositol 5-phosphatase 2 (SHIP2). Methods Using the yeast two-hybrid system, P1 (SH2+5-Ptase) and P2 (PRD+SAM) segments of SHIP2 were used as bait proteins to screen the proteins that bind to SHIP2 from the homogenous cDNA library of human gastric mucosal epithelium. The selected interacting proteins of SHIP2 were verified by co-immunoprecipitation assay. Results A total of 39 positive clones were selected and sequenced for alignment analysis. It was verified that PHB interacted with SHIP2 by reductive hybridization and co-immunoprecipitation assays. Conclusion PHB, the interacting protein of SHIP2 was screened by yeast two-hybrid system from the homogenous cDNA library of human gastric mucosal epithelium.

Lanosterol synthase( LS) is a key enzyme involving in the mevalonate pathway( MVA pathway) to produce lanosterol,which is a precursor of ganoderma triterpenoid. And the transcriptional regulation of LS gene directly affects the content of triterpenes in Ganoderma lucidum. In order to study the transcriptional regulation mechanism of LS gene,yeast one-hybrid technique was used to screen the transcription regulators which interact withthe promoter of LS. The bait vector was constructed by LS promoter,then the vector was transformed yeast cells to construct bait yeast strain. One-hybrid c DNA library was constructed via SMART technology. Then the c DNA and p GADT7-Rec vector were co-transformed into the bait yeast strain to screen the upstream regulatory factors of the promoter region of LS by homologous recombination. Total of 23 positive clones were screened. After sequencing,blast was performed against the whole-genome sequence of G. lucidum. As a result,8 regulatory factors were screened out including the transcription initiation TFIIB,the alpha/beta hydrolase super family,ALDH-SF superfamily,60 S ribosomal protein L21,ATP synthase β-subunit,microtubule associated protein Cript,prote asome subunit β-1,and transaldolase. Until now,the regulation effect of these 8 regulatory factors in G.lucidum has not been reported. This study provides candidate proteins for in-depth study on the expression regulation of LS.

Breeding by design is a new concept proposed in the beginning of the century. It refers to the breeding of varieties by crop design utilizing favorable alleles dispersed in different genetic resources in a genome. In the past 20 years, we have proposed a "three-step" strategy to carry out the research on breeding by design in rice. Firstly, we constructed a library of chromosomal single-segment substitution lines (SSSLs) by using of Huajingxian74 (HJX74), an elite xian (indica) variety from South China as the recipient and 43 accessions of seven species of rice AA genome as donors. The genes in the substituted segments of SSSLs were then detected. Breeding by design was conducted by selecting the favorable genes from the SSSL library. Our practice indicates that the SSSL library is a powerful platform for breeding by design and various "traits", "lines" and "varieties" of rice can be designed and bred by utilizing abundant genes in the SSSL library. Here, we introduce the platform of the HJX74-SSSL library and our work of breeding by design on the platform. It will provide a case study for crop design.

Objective: To optimize DNA library construction in non-crosslinked chromatin immunoprecipitation coupled with next-generation sequencing (Native ChIP-seq) to obtain high-quality Native ChIP-seq data., Methods: Human nasopharyngeal carcinoma HONE1 cell lysate was digested with MNase for release of the nucleosomes, and the histone-DNA complexes were immunoprecipitated with specific antibodies. The protein component in the precipitate was digested with proteinase K followed by DNA purification; the DNA library was constructed for sequence analysis., Results: Compared with the conventional DNA library construction, Tn5 transposase method allowed direct enrichment of the target DNA after Tn5 fragmentation, which was simple, time-saving and more efficient. The IGV visualized map showed that the information obtained by the two library construction methods was consistent. The sequencing data obtained by the two methods revealed more signal enrichment with Tn5 transposase library construction than with the conventional approach. H3K4me3 ChIP results showed a good reproducibility after Tn5 transposase library construction with a signal-to-noise ratio above 50%., Conclusions: Tn5 transposase method improves the efficiency of DNA library construction and the results of subsequent sequence analysis, and is especially suitable for detecting histone modification in the DNA to provide a better technical option for epigenetic studies.

With the development of various biotechnology,the research on molecular genetics of medicinal plants has gradually deepened. In this paper,the research system of molecular genetics of medicinal plants was proposed for the first time,which was elaborated from the aspects of genetic resources,genome,gene function and research methods. The application fields of medicinal plant mainly contain species identification,molecular breeding and biosynthesis. The research directions of molecular genetics of medicinal plants in genetic resources,model platform,synthetic biology and molecular breeding were put forward,which include 1 000 genome projects of medicinal plants,model species and mutant libraries,gene original libraries of heterologous synthetic systems,construction gene original library and specific chassis cells in heterologous synthesis system of active ingredient,breeding of new varieties of medicinal plants with high active ingredient and high resistance based on molecular markers andtransgenes.

Objective To construct a random mutagenesis library of 3E1D7, a chimerical antibody against c-mesenchymal epithelial transition factor (c-Met), using mammalian cell surface display. Methods Antibody genes with randomly mutated complementarity-determining region 3 (CDR3) part were inserted into the mammalian expression plasmid pSZI-CD to construct the random mutagenesis library using double enzyme digestion. Reconstructed plasmids were then cloned into CHO cells by transfection. The expression level of antibodies on the surface of CHO cells was checked by C6 PLUS flow cytometry. Results 3E1D7 random mutagenesis library was successfully constructed with a volume of 5.52×10 6 in diversity on gene level. Sequence analysis showed that all 20 clones randomly picked from the library coded for 20 different mutated amino acid sequences in open reading frames. After transfection, the expression of full-length antibodies on CHO cell surfaces could be detected by flow cytometry. Conclusion A random mutagenesis library of a certain anti-c-Met antibody has been successfully constructed with an exhibitable diversity of 5.52×10 6 , which would be a useful platform for further screening of therapeutic antibodies.

Trichoderma reesei Rut-C30 is widely used in industrial cellulase production, and development of cellulase hyper-producer is of great importance for economic lignocellulosic biorefinery. In this study, T. reesei Rut-C30 was engineered with an artificial zinc finger proteins (AZFPs) library. Two mutants T. reesei M1 and M2 with improved cellulase production were obtained. Compared to the parent strain, the filter paper activity (FPase) of T. reesei M1 and M2 increased 100% and 53%, respectively. In addition, the total amount of extracellular protein from the M1 mutant increased 69%, whereas the endo-β-glucanase (CMCase) activity of the M2 mutant is 64% higher compared to the parental strain. Furthermore, RT-qPCR analysis showed that the major cellulase genes exhibited significantly increased expression in both mutants, but different patterns were observed in the two mutants. On the other hand, the cellulase transcriptional repressor ace1 was down-regulated in both mutants, but the transcription level of the activator xyr1 was only up-regulated in the strain M1. These results demonstrated that different AZFPs exert diverse regulatory mechanisms on cellulase production in T. reesei. Analysis of the target genes of AZFPs from T. reesei M1 and M2 will not only benefit further exploration of the regulatory mechanisms of cellulase biosynthesis in T. reesei, but also enable development of cellulase hyper-producing strains by metabolic engineering.

An in vitro synthesized random ssDNA library was subjected to 12 rounds of selection against anti-screening cells and sieving cells by SELEX. Normal and inflammatory cervical exfoliation cells were selected as anti-screening cells, and the cervical exfoliation cells of low-grade squamous intraepithelial lesion (CIN1), high-grade squamous intraepithelial lesion (CIN2, CIN3) and cervical carcinoma were selected as sieving cells during the screening process. Then, the highly specific aptamer CIN-Ap4 was established by the analysis of the specificity, affinity and cell immunofluorescence, which can be used as biomarker for Cervical Intraepithelial Neoplasia. Prime Premier 5.0 was applied to design a random ssDNA library. According to the fixed sequence at both ends of the library, a pair of primers were designed and synthesized. At the same time, the optimal annealing temperature, cycle times and primer concentration ratio of PCR procedure were selected. The results under the optimal condition are shown as follows. In the 50 μL reaction system, the optimum reaction conditions of symmetry PCR are as follows: annealing temperature is 49.5 ℃, number of cycles is 15. The optimal reaction conditions of indirect asymmetric PCR are as follows: the primer concentration ratio is 80:1, and the number of cycles is 35. The experiment proves that the oligonucleotide library is constructed successfully, and the highly specific dsDNA and ssDNA can be obtained under optimal PCR conditions with good repeatability, which establishes the foundation for the further exploration and experimentation.

The study is aimed to construct high quality Salvia miltiorrhiza cDNA library and obtain the SmJAZ8 gene of S. miltiorrhiza by yeast two-hybrid system. In this study， full-length cDNA was synthesized from roots， stems， leaves， flowers and hairy roots of S. miltiorrhiza. The full-length cDNA library was synthesized by SMART method and constructed with DSN homogenization technique. The results showed that the library capacity was 1.45×10⁶， the recombination rate was 100%， and the average size of the insert was 500-2 000 bp. The recombinant vector of pDEST-pGADT7-SmJAZ8 was constructed and transformed into Y2HGold strain. The interaction protein was screened by yeast two-hybrid system. The DnaJ protein and UBQ protein were screened by yeast two-hybrid system. This study has successfully constructed a full-length cDNA library of S. miltiorrhiza， and laid the foundation for the follow-up study on functional gene screening and gene function of S. miltiorrhiza., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Chinese Pharmaceutical Association.)

To develop a high-yield pyruvate strain, we first engineered a pyruvate-producing Escherichia coli KLPP from wild-type E. coli MG1655 by blocking the pathways for byproduct formation via gene knockout. Then, we built a library of mutant containing 7 197 monoclones by using the pUT Mini-Tn5 transposon vector for random mutagenesis with E. coli KLPP. We developed a high-throughput method for pyruvate detection based on dinitrophenylhydrazine reaction using 96-well microplate reader. After two-round screening we successfully obtained six mutants with increased pyruvate titer using this method, the titer of pyruvate was increased by 38%, 31%, 19%, 28%, 44% and 14%, respectively. The position of transposon insertion was determined by whole genome re-sequencing, and the gene locus possibly influencing pyruvate production was analyzed, which laid the foundation for subsequent strain improvement by metabolic engineering.

Objective: To screen and identify the mutations in Kawasaki disease by targeted enrichment of genomic region sequencing technique and investigate susceptibility genes associated with coronary artery lesion. Method: This was a case-control study.A total of 114 patients diagnosed as Kawasaki disease treated in Shanghai Children's Hospital between December 2015 and November 2016 were studied and another 45 healthy children who were physically examined in outpatient department were enrolled as control group. Patients were divided into two groups based on the results of echocardiogram. Peripheral venous blood was obtained from patients and controls. Genomic DNA was extracted. SeqCap EZ Choice libraries were prepared by targeted enrichment of genomic region technology. Then the libraries were sequenced to identify susceptibility genes associated with coronary artery lesion in patients diagnosed as Kawasaki disease.Susceptible genes were identified by Burden test, Pearson chi-square test or Fisher's exact probability test. Result: There was statistically significant difference in TNFRSF11B(rs2073618)G>C(p.N3K)mutation and GG/GC/CC genotype between Kawasaki disease group and control group(χ(2)=15.52, P =0.00). There was statistically significant difference in TNFRSF13B(rs34562254)C>T(p.P251L)mutation(χ(2)=10.40, P =0.01)and LEFTY1(rs360057)T>G(p.D322A)mutation(χ(2)=8.505, P =0.01)between patients with coronary artery lesions and those without. Conclusion: Targeted enrichment of genomic region sequencing technology can be used to do primary screening for the susceptible genes associated with coronary artery lesions in Chinese Kawasaki patients and may provide theoretical basis for larger sample investigation of risk prediction score standard in Kawasaki disease.

Objective To establish the primary cat intestinal epithelial cells (IECs) culture methods and construct the cDNA library for the following yeast two-hybrid experiment, so as to screen the virulence interaction factors among the final host. Methods The primary cat IECs were cultured by the tissue cultivation and combined digestion with collagenase XI and dispase I separately. Then the cat IECs cultured was identified with the morphological observation and cyto-keratin detection, by using goat anti-cyto-keratin monoclonal antibodies. The mRNA of cat IECs was isolated and used as the template to synthesize the first strand cDNA by SMART™ technology, and then the double-strand cDNAs were acquired by LD-PCR, which were subsequently cloned into the plasmid PGADT7-Rec to construct yeast two-hybrid cDNA library in the yeast strain Y187 by homologous recombination. Matchmaker™ Insert Check PCR was used to detect the size distribution of cDNA fragments after the capacity calculation of the cDNA library. Results The comparison of the two cultivation methods indicated that the combined digestion of collagenase XI and dispase I was more effective than the tissue cultivation. The cat IECs system of continuous culture was established and the cat IECs with high purity were harvested for constructing the yeast two-hybrid cDNA library. The library contained 1.1×10 6 independent clones. The titer was 2.8×10 9 cfu/ml. The size of inserted fragments was among 0.5-2.0 kb. Conclusion The yeast two-hybrid cDNA library of cat IECs meets the requirements of further screen research, and this study lays the foundation of screening the Toxoplasma gondii virulence interaction factors among the cDNA libraries of its final hosts.

Objective: To identify and clone the polymerase Ⅲ U6 promoter from Cryptococcus neoformans (CnU6 promoter), and verify if CnU6 promoter can effectively transcribe shRNA and gRNA of CRISPR/Cas9 system., Methods: Combining the C. neoformans genome information published in GenBank database and RNA-seq library data from our laboratory, we obtained the U6 RNA sequence with high transcriptional level by bioinformatics analysis. The putative CnU6 promoter was ligated upstream of shRNA and gRNA by EasyGeno and overlapping PCR respectively. Based on shRNA-mediated target gene silence phenotype by RNAi and gene mutation by gRNA-guided Cas9 nuclease mediated target sites editing by CRISPR/Cas9 system, we could identify if CnU6 promoter could drive the transcription of short RNA., Results: CnU6 promoter could drive the transcribtion of shRNA, which could silence the target gene, and gRNA, which could guide Cas9 nuclease to cut the target site., Conclusion: The CnU6 promoter from C. neoformans was successfully identified and cloned, which could drive the transcription of shRNA and gRNA efficiently.

Objective: To obtain DNA aptamers with a highly specific affinity to HIV gp41 antigen using SELEX screening for detection of HIV., Methods: The specific DNA aptamers of HIV gp41 antigen were screened from the double-stranded DNA derived from the single-stranded DNA (ssDNA) library with agarose beads as the supportive medium and HIV gp41 antigen as the target molecule using SELEX technique and real-time quantitative PCR., Results: The secondary ssDNA library obtained after 6 rounds of screening was amplified by PCR to obtain dsDNA. The dsDNA was linked with pMD TM 18-T vector, cloned and sequenced to obtain 4 aptamers of HIV gp41 antigen. The affinities of the 4 aptamers (K d ) all reached the nanomolar level. Among the 4 aptamers, the No.15 aptamer showed the strongest affinity. Specificity analysis of the aptamers revealed that all these 4 aptamers had specific affinity to HIV gp41 antigen with no affinity to other non-specific proteins., Conclusion: We successfully obtained DNA aptamers with highly specific affinity to the HIV gp41 antigen from random single-stranded oligonucleotide library, and the obtained aptamers have the ability to antagonize HIV gp41 antigen.

To establish a method for measurement of the neutralizing activity of a monoclonal antibody against the rabies virus. Twenty-four rabies street virus-positive samples were isolated by the mouse inoculation test. Isolated rabies street viruses were cultured and the virus titer tested in N2A cells. We established a rabies street virus bank with viruses that could adapt to the growth of N2A cells with a high titer. Then repeatability was evaluated after three detections of the TRN006 monoclonal antibody. Of the 24 positive samples,15 strains of the virus could adapt to N2A cells and form fluorescent foci in cells.Finally,10 strains with a high titer were selected for the rabies street virus bank, which covered nine Provinces of China and four Chinese lineages. Three lineages were used for the neutralization test for the monoclonal antibody, and the Student’s t-test showed that it had good repeatability.

Objective To construct the ribosome display library of anti-B7-H4 extracellular domain, and select the antibody with high specificity. Methods The cDNA of B7-H4 extracellular domain was amplified from A549 cells by reverse transcription PCR (RT-PCR). To express ectodomains of B7-H4, the sequence of B7-H4 gene, which encodes the B7-H4 extracellular domains, was inserted into plasmid pET-28a(+). The purified recombinant protein of B7-H4 extracellular domain was used to immunize BALB/c mice. The total RNA was extracted from the spleen of BALB/c mice which had been immunized with B7-H4 recombinant protein. The genes of VH, Vκ and VH/Vκ were amplified separately by RT-PCR and splicing by overlap extension PCR (SOE-PCR). The gene of VH/ Vκ was ligated into pUM19-T vector and the ligated sample was transformed into competent E.coli DH5α. The resulting plasmid was isolated and then subjected to sequencing to verify the gene sequence. TNT(R)T7 Quick for PCR DNA kit was used to translate and screen the anti-B7-H4-scFv in vitro from the ribosome display library. Western blotting and an indirect ELISA were performed to detect the specificity of anti-B7-H4-scFv. Results The right sequences of VH, Vκ and VH/Vκ were acquired, which were 439, 680 and 1098 bp in length, respectively. The analysis of specificity demonstrated that the anti-B7-H4-scFv screened from the ribosome display library had a high specific combining ability with B7-H4. Conclusion The experiment has successively constructed the ribosome display library of anti-B7-H4 extracellular domain, and selected the anti-B7-H4-scFv which has a high specific binding ability with recombinant protein of B7-H4 extracelluar domain.

Objectives: To construct a cDNA phage expression library for human esophageal cancer cells., Methods: After the total RNA were obtained from esophageal cancer cells, the mRNA were separated with magnetic beads adsorption method, and the single-strand and double-strand cDNA were synthesized through reverse transcription. With the undesirable cDNA fragments removed, the remaining cDNA (linked with Eco R1 aptamer and phosphorylated its 5'end) combined with the carrier of T7 Select10-3b. The recombinant phage were packaged in vitro for preliminary cDNA library. PCR was used to identify the size of inserted cDNA., Results: The constructed original cDNA phage expression library for human esophageal cancer cells was consisted of 2.01×10⁶ pfu/mL bacteriophages with a recombination rate of 100%. The length of the inserted cDNA fragments were range from 300 bp to 1 500 bp., Conclusions: The cDNA phage expression library of human esophageal cell is successfully constructed to meet the currently recognized standards, and can be well used to screen cDNA-cloned genes of human esophageal cancer antigens by serological analysis of recombinantly expressed cDNA clone (SEREX).

Objective: The goal of this study was to identify uncultured actinobacterial diversity in Xinjiang Ebinur salt lake sediment., Methods: Total DNA was extracted from 5 sediments of Ebinur lake and the actinobacterial 16S rRNA gene clone libraries were constructed through touchdown PCR program with the common primers. White clones were randomly selected after blue-white spot screening and detected by PCR. Positive clones were analyzed by restriction fragment length polymorphism (RFLP) with restriction enzyme Hha Ⅰ, and clones with unique RFLP were selected to analyze their sequences. After Chimera Check analysis, the sequence homology was analyzed by BLAST and phylogenetic tree was constructed by MEGA 5.0 software., Results: In total 192 white clones were randomly selected and 166 clones were positive clones. The sequences of 51 clones with unique RFLP were analyzed and detected with Check Chimera program. The results show that 36 OTUs were obtained and GenBank accession numbers were KR182090-KR182131. The library coverage C value was 90.4% and 36 OTUs could be divided into 2 clusters by phylogenetic analysis. The first cluster accounted for 18.1% of the library and belonged to one class Actinobacteria of phylum Actinobacteria, which contained 4 orders including Actinomycetales, Propionibacteriales, Micrococcales and Corynebacteriales. Another cluster was the unclassified actinobacteria, divided into 3 groups and accounted for 81.9% of the library., Conclusion: Ebinur Lake has a lot of unknown actinobacteria that need to be further investigated.

Using of high throughput sequencing technology to study the microbial diversity in complex samples has become one of the hottest issues in the field of microbial diversity research. In this study, the soil and sheep rumen chyme samples were used to extract DNA, respectively. Then the 25 ng total DNA was used to amplify the 16S rRNA V3 region with 20, 25, 30 PCR cycles, and the final sequencing library was constructed by mixing equal amounts of purified PCR products. Finally, the operational taxonomic unit (OUT) amount, rarefaction curve, microbial number and species were compared through data analysis. It was found that at the same amount of DNA template, the proportion of the community composition was not the best with more numbers of PCR cycle, although the species number was much more. In all, when the PCR cycle number is 25, the number of species and proportion of the community composition were the most optimal both in soil or chyme samples.

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.

Objective: To establish a novel approach based on DNA barcode sequence, so as to guarantee the quality stability of Chinese medicinal materials., Methods: Eight species of Paris plants were collected, and a standard DNA barcode library was developed by ITS loci. Furthermore, the barcodes also used to identify the seed and seedling products that purchased from the markets., Results: ITS loci can stably and accurately distinguish Paris polyphylla var. yunnanensis and its adulterants., Conclusion: The seeds and seedlings of Chinese medicinal materials need to be properly authenticated before planting,and DNA barcoding has been found to be effective for this purpose.

Objective: To further study Fagopyrum tataricum genome and to screen the functional genes., Methods: The variety JINQIAO No. 2( Fagopyrum tataricum) native to Shanxi, was used for BAC library construction. The high molecular weight DNA( HMWDNA) was isolated from Fagopyrum tataricum leaves used the methods of Peterson. The HMW-DNA was cut by Hind Ⅲ and ligated to BAC vectors; the ligations were transformed into Escherichia coli DH10 B. Then 48 BAC clones were randomly selected and sequenced BAC end sequences., Results: The library consisted of 30 000 clones with an average insert size of about 123 kb and the empty clone ratio was less than 1%. The library represented an equivalent about 6. 9 fold size of Fagopyrum tataricum genome. Which obtained 89 BAC end sequences,among which 7 sequences( 8%) had alignment results when comparing with NCBI Gen Bank database. The blast hits contained some genes with known function,such as rpo Tm2,Trrap and MDR1 genes,etc. Those genes were associated with DNA binding, transmembrane transport and phosphotransferase activity function. And it was also found that the sequence of 40G19-F was probably repetitive sequences in Fagopyrum tataricum genome., Conclusion: The BAC library will be helpful for the gene cloning and whole genome sequencing of Fagopyrum tataricum.

Objective: To clone the biosynthetic gene clusters for secondary metabolites, we developed the genetic modification system and constructed a genomic library of Streptomyces luteosporeus NRRL 2401., Methods: The genetic modification system was developed by using conjugal transfer vectors pSET152, pPM927 and pJTU1278 which were transferred from Escherichia coli ET12567/pUZ8002 to S. luteosporeus. The genomic library of S. luteosporeus NRRL 2401 was constructed by the fosmid vector pCClFOS, with E. coli EP1300 -T1 as the host strain. A PCR-based method was then developed for screening the biosynthetic gene clusters of secondary metabolites in the constructed genomic library., Results: Vectors pSET152, pPM927 and pJTU1278 were successfully transferred into S. luteosporeus for genetic modification, with pSET152 presenting the highest transformation efficiency. The constructed genomic library of S. luteosporeus NRRL 2401 contained 2880 clones with an average -35 kb inserted DNA fragment in each clone, indicating the 99.99% coverage of the genome in the library. In this genomic library, we detected 9 clones containing possible indolmycin biosynthesis genes by the PCR-based screening method., Conclusion: A stable, efficient genetic modification system and high-quality genomic library could be used for discovery of the biosynthetic gene clusters for secondary metabolites in S. luteosporeus NRRL 2401.

Multidrug resistant genes are highly expressed in hepatocellular carcinoma that seriousty affects the effect of chemotherapy. Screening of resistant genes from HCC cells and studying its mechanism of drug resistance will be helpful to improve the effecacy of chemotherapy for hepatocellular carcinoma. Here we described an alternative method called cyclical packaging rescue (CPR). First we constructed a retrovirus cDNA library of hepatoma cells and used it to infect fibroblasts. Then we added drugs to screen survival cells. The survival cells, stably integrated helper-free retroviral libraries, were recovered rapidly after transfection with plasmids expressing retroviral gag-pol and env genes. Through this method, retroviral RNAs were directly repackaged into new infectious virions. Recovered retroviral supernatant was then used to reinfect fresh target cells. When performed in concert with selection using functional assays, cDNAs regulating functional responses could be identified by enrichment through multiple rounds of retroviral library recovery and retransmission. Using CPR, we obtained several cDNAs. After a preliminary detection, we found Ribosomal protein S11 (RPS11), Ribosomal protein L6 (RPL6), Ribosomal protein L11 (RPL11), Ribosomal protein L24 (RPL24) possibly had drug resistant function.

For engineering an efficient butanol-producing Escherichia coli strain, many efforts have been paid on the known genes or pathways based on current knowledge. However, many genes in the genome could also contribute to butanol production in an unexpected way. In this work, we used Tn5 transposon to construct a mutant library including 1 196 strains in a previously engineered butanol-producing E. coli strain. To screen the strains with improved titer of butanol production, we developed a high-throughput method for pyruvate detection based on dinitrophenylhydrazine reaction using 96-well microplate reader, because pyruvate is the precursor of butanol and its concentration is inversely correlated with butanol in the fermentation broth. Using this method, we successfully screened three mutants with increased butanol titer. The insertion sites of Tn5 transposon was in the ORFs of pykA, tdk, and cadC by inverse PCR and sequencing. These found genes would be efficient targets for further strain improvement. And the genome scanning strategy described here will be helpful for other microbial cell factory construction.

In recent years, the antigen recognition mechanism based on variable lymphocyte receptors (VLRs) was found in agnathan lamprey. To illuminate the genetic basis of immune response of lymphocyte-like cells in the mucosal immune system of lamprey and explore the evolutionary relationship of adaptive immune responses between the jawless and jawed vertebrates, we constructed cDNA libraries of lamprey (Lampetra japonica) gills before and after stimulation, and then performed high-throughput transcriptome sequencing and analysis. Through functional annotation of 88 525 assembled unigenes, 21 704 and 9769 unigenes were annotated in Gene Ontology (GO) and Kyto Encyclopedia of Genes and Genomes (KEGG) databases, respectively. Among 999 unigenes involved in multiple pathways of immune system, 184 unigenes were highly homologous to 51 TCR (T cell receptor) and BCR (B cell receptor) signalling molecules in higher vertebrates, indicating that molecules involved in adaptive immune signalling pathways in higher vertebrates also exist in lampreys. In addition, identification of five VLRA, seven VLRB and four VLRC molecules suggest that at least three types of lymphocyte subsets are distributed in lamprey gill mucosal immune tissues. The results of real-time fluorescence quantitative PCR showed that the expression levels of Lck, Fyn and Zap70 were up-regulated after immune stimulation while those of Syk, Btk and Blnk were not changed significantly, indicating the activation of TCR-like signal transduction pathway after antigen stimulation in lamprey gill tissues. Our studies preliminaryly proved that two parallel adaptive immune systems in jawless and jawed vertebrates have common genetic basis, and also provided valuable clues to the exploration of signalling processes of VLRA⁺, VLRB⁺, and VLRC⁺ lymphocyte-like cells in response to antigens.

Abstract: In order to more accurately understand community structure and diversity of actinomycetes in saline-alkali soil from Jiuquan area of Hexi Corridor, the community structure and diversity from three kinds of soil samples (primary, secondary saline alkali soil and farmland soil) were analyzed using uncultured methods. The results showed that the 16S rDNA clone library of actinomycetales from the primary saline-alkali soil belonged to 19 OTUs, Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae and unknown groups of Actinomycetales; the 16S r DNA clone library of actinomycetales from the secondary saline-alkali soil belonged to 14 OTUs, Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae and unknown groups of Actinomycetales; the 16S rDNA clone library of farmland soil belonged to 7 OTUs, Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae and unknown groups of Actinomycetales; Micrococcineae was the common population in the three soils, and also was the dominant population in primary saline alkali soil and farmland soil. The diversity index and rarefaction curves analysis showed that actinomycetes species richness was in order of primary saline-alkali soil > secondary saline-alkali soil > farmland soil. The dilution curves of primary saline-alkali soil and secondary saline-alkali soil were not leveled off, which indicated the actinomycetes diversity in saline-alkali soil was more enriched than the actual. The rich and diverse actinomycetes resources in saline-alkali soil from Jiuquan area of Hexi Corridor provide important data on the actinomycetes ecology distribution research, exploitation and utilization in saline-alkali soil.

Objective: To characterize the biological function of calmodulin (CaM) from Clonorchis sinensis (C. sinensis, Cs) and investigate its role in clonorchiasis-associated hepatic fibrosis., Methods: The full-length sequence of CsCaM gene was isolated from Cs cDNA library and its homologues were searched using BLASTx for comparison. Bioinformatics analysis was performed to compare the homologues and predict the physiochemical characteristics and functional domains. The gene was cloned in a prokaryotic plasmid and expressed in E. coli, and the recombinant protein was purified by affinity chromatography for immunizing rats to produce polyclonal antibodies, whose titer was determined using ELISA analysis. Immunoblotting analysis was carried out to determine of the purity and antibody recognition of CsCaM. Immunofluorescence assay was employed to analyze the tissue location of the protein. A rat model of liver fibrosis was established by introperitoneal injection of the recombinant protein., Results: The recombinant CsCaM protein obtained contained 150 amino acids with a theoretical molecular mass of 23.4 kD. CsCaM homologue had EF hand motifs. The recombinant pET-30a-CsCaM plasmid expressed in BL21 E. coli was about 23.4 kD. The total IgG antibody titer in the immunized mice reached the peak level (over 1: 51200) 2 to 4 weeks after the first injection. Immunohistochemistry showed that CsCaM located in the testis of adult C. sinensis. The rats receiving intraperitoneal injection of CsCaM showed severe liver inflammation with mild to moderate liver fibrosis., Conclusion: The pro-inflammation and pro-fibrosis effects of CsCaM in rat liver suggest its involvement in clonorchiasis- associated hepatic fibrosis.

Objective: To immunoscreen the gene encoding thioredoxin peroxidase (TPx) from a cDNA library made from adult Fasciola gigantica worms, clone and express the gene, and evaluate the immunodiagnostic value of TPx recombinant protein., Methods: The A ZAP cDNA library was immunoscreened with pooled serum of fascioliasis gigantica patients. The obtained positive clones were sequenced and analyzed by multiple sequence alignment. The full-length (rFgTPx) and N-termianal truncated (rFgTPx&#95;nt) sequence of FgTPx was subcloned into prokaryotic plasmid pET28a(+) with a non-fusion expression technique, respectively. The recombinant proteins of rFgTPx and rFgTPx&#95;nt were purified by His-bind affinity column (Ni-NTA). rFgTPx and rFgTPx&#95;nt were used in indirect ELISA to test the antibody response of the serum samples. Sera of 27 fascioliasis gigantica patients, 15 patients with schistosomaisis japonica, 15 clonorchiasis sinensis patients, and 32 healthy donors were tested by using the recombinant protein based ELISA., Results: The TPx recombinant proteins were obtained through expression, purification and renaturation, the relative molecular mass of rFgTPx and rFgTPx&#95;nt were Mr 30,000 and Mr 26,000, respectively. The total diagnostic coincidence rate, sensitivity and specificity of rFgTPx&#95;nt-based ELISA was 87.6% (78/89), 66.7% (18/27), and 96.8% (60/62), respectively. The cross reaction with Schistosoma japonicum and Clonorchis sinensis was 0 and 1/15 for rFgTPx&#95;nt, respectively. Before and after treatment, A450 value of the serum samples from fascioliasis patients was 0.233 ± 0.088 and 0.129 ± 0.072, respectively (t = 4.27, P < 0.01)., Conclusion: The gene encoding TPx is expressed in the prokaryotic expression system. The recombinant protein shows proper sensitivity and high specificity for the serodiagnosis of Fasciola gigantica infection.

To determine the community structure of airborne microbes in Qingdao downtown in autumn, the airborne bacteria and fungi were collected by the KC-6120 air sampler and analyzed using the 16S/18S rDNA gene clone library method. Phylogenetic analysis of airborne bacteria showed that they belonged to six major phylogenetic groups: Proteobacteria (78. 8%), Firmicutes (14.6%), Actinobacteria (4.0%), Planctomycetes (1.3%), Cyanobacteria (0.7%), and Deinococcus-Thermus (0.7%). The dominant genera of airborne bacteria included Acinetobacter (39.7%), Staphylococcus (11.3%), Sphingomonas (8.6%), Paracoccus (6.0%) and Massilia (5.3%). The main types of airborne fungi were Ascomycota (97.5%) and Basidiomycota (2.5%). Dominant genera of airborne fungi included Pyrenophora (76.5%), Xylaria (13.6%) and Exophiala (2.5%). The pathogens or conditioned pathogens, such as Acinetobacter, Staphylococcus, or Sphingomonas were detected in the airborne bacteria, whereas certain kinds of fungi, such as P. graminea, X. hypoxylon and Zasmidium angulare that could cause a variety of crop diseases were also detected.