三种乳源生物活性肽的二肽基肽酶-Ⅳ抑制活性研究

通过从分化成熟的人克隆结肠腺癌细胞(Caco-2细胞)中提取二肽基肽酶-Ⅳ(DPP-Ⅳ)建立体外筛选DPP-Ⅳ抑制剂的模型,用Ile-Pro-Ile(IPI)作为阳性对照测定其半抑制质量浓度(IC_(50))评价该模型,并测定3种来源于酪蛋白的四肽Leu-Pro-Leu-Pro(LPLP)、Gln-Glu-Pro-Val(QEPV)和Asp-Gln-Leu-Gln(DELQ)的抑制率,研究了DPP-Ⅳ抑制肽的抑制类型和复合抑制作用。实验结果表明:IPI的IC_(50)为(31.51±1.51)μg/m L,与文献报道的相近,证明该模型可以应用于DPP-Ⅳ抑制剂的筛选;LPLP的IC_(50)为(0.84±0.06)mg/m L,QEPV的IC_(50)为(14.45±1.07)mg/m L而DELQ的IC_(50)大于100 mg/m L,即LPLP和QEPV具有一定的抑制作用;LPLP和QEPV的作用均为非竞争性机制,并且两种多肽联合对DPP-Ⅳ抑制作用为协同抑制作用。

医学遗传学

0031678 ZAP 基因:胰腺外分泌部分的新一代增殖基因[德,英摘]/Gnther R//Med Klin.-1999,94(4).-233～238同医图佣31679因子v玩记en突变的载体致命性丧失增加的危险/Mein田月iJR// Anllln-tem Med一1999,130(9)一736一739 医科情以,316圈)

Cloning and Prokaryotic Expression of P23 Major Surface Protein Gene from Theileria sergenti

[Objective] The aim was to study cloning and prokaryotic expression of P23 major surface protein gene of Theileria sergenti. [Method] A pair of specific primers was designed according to the sequence of P23 major surface protein of T. sergenti (D84447).The P23 gene was amplified by PCR from genomic DNA of T. sergenti and cloned into pMD18-T vector to construct recombinant clonal vector pMD18-P23. Positive clones were identified by PCR screening and restriction digestion. A recombinant expression plasmid pGEX-4T-P23 was constructed by subcloning the cloned P23 gene into the linearized pGEX-4T-1 vector and transformed into E. coli BL21. After introduction by IPTG,the expressed fusion protein was identified by SDS-PAGE and Western-blotting. [Result] The cloned gene has a total length of 507 bp. Sequencing result showed that the nucleotide sequence of the cloned P23 gene shared 99.4% identity with that of P23 published in GenBank (D84447). The expressed fusion protein was 46 ku in molecular mass. Induction opportunity of zhours after culture inoculation was the best,the induction time of 6 h was the best,and induction temperature of 34 ℃ was the best as well,IPTG of 1 mmol/L had little effect on the expression. Western-blotting indicated that recombinant protein was recognized by specific antibody. [Conclusion] This study would lay a foundation for further research on the prevention and diagnose of T. sergenti.

Cloning and Expression Analysis of a Human Putative Tumor Suppressor Gene Homologue from Rice

A gene homologous to the human Putative tumor suppressor gone QM, designated OSQM1, was isolated from rice (Oryza sativa L.) genomic DNA library using through homology screening. It contained 4 exons and 3 introns, encoding a protein of 219 amino acids with 46 basic amino acids, leading to a high isoelectric point of 11.02. Homology search showed that this gene existed in eukaryotes and highly conserved throughout eukaryotes, suggesting an essential role of this gene. Northern Not analysis showed that it was expressed in various rice organs, but at lower level in developing flower and callus tissue than in other vegetative organs. Its expression levels in roots and leaves were influenced by different environmental factors.

Cloning of cytochrome P-450 2C9 cDNA from human liver and its expression in CHL cells

AIM: Using bacterial, yeast, or mammalian cell expressing a human drug metabolism enzyme would seem good way to study drug metabolism-related problems. Human cytochrome P-450 2C9(CYP2C9) is a polymorphic enzyme responsible for the metabolism of a large number of clinically important drugs. It ranks among the most important drug metabolizing enzymes in humans. In order to provide a sufficient amount of the enzyme for drug metabolic research, the CYP2C9 cDNA was cloned and expressed stably in CHL cells. METHODS: After extraction of total RNA from human liver tissue, the human CYP2C9 cDNA was amplified with reverse transcription-polymerase chain reaction (RT-PCR), and cloned into cloning vector pGEM-T. The cDNA fragment was identified by DNA sequencing and subcloned into a mammalian expression vector pREP9. A transgenic cell line was established by transfecting the recombinant vector of pREP9-CYP2C9 into CHL cells. The enzyme activity of CYP2C9 catalyzing oxidation of tolbutamide to hydroxy tolbutamide in S9 fraction of the cell was determined by high performance liquid chromatography(HPLC). RESULTS: The amino acid sequence predicted from the cDNA segment was identical to that of CYP2C9*1, the wild type CYP2C9. However, there were two base differences, i.e. 21T】C, 1146C】T, but the encoding amino acid sequence was the same, L7, P382. The S9 fraction of the established cell line metabolizes tolbutamide to hydroxy tolbutamide; tolbutamide hydroxylase activity was found to be 0.465 +/- 0.109 micromol.min(-1).g(-1) S9 protein or 8.62 +/- 2.02mol.min(-1).mol(-1) CYP, but was undetectable in parental CHL cell. CONCLUSION: The cDNA of human CYP2C9 was successfully cloned and a cell line of CHL- CYP2C9, efficiently expressing the protein of CYP2C9, was established.

WWOX induces apoptosis and inhibits proliferation of human hepatoma cell line SMMC-7721

AIM: To investigate the effects of the WWOX gene on the human hepatic carcinoma cell line SMMC-7721. METHODS: Full-length WWOX cDNA was amplified from normal human liver tissues. Full-length cDNA was subcloned into pEGFP-N1, a eukaryotic expression vector. After introduction of the WWOX gene into cancer cells using liposomes, the WWOX protein level in the cells was detected through Western blotting. Cell growth rates were assessed by methyl thiazolyl tetrazolium (MTT) and colony formation assays. Cell cycle progression and cell apoptosis were measured by flow cytometry. The phosphorylated protein kinase B (AKT) and activated fragments of caspase-9 and caspase-3 were examined by Western blotting analysis. RESULTS: WWOX significantly inhibited cell proliferation, as evaluated by the MTT and colony formation assays. Cells transfected with WWOX showed significantly higher apoptosis ratios when compared with cells transfected with a mock plasmid, and overexpression of WWOX delayed cell cycle progression from G1 to S phase, as measured by flow cytometry. An increase in apoptosis was also indicated by a remarkable activation of caspase-9 and caspase-3 and a dephosphorylation of AKT (Thr308 and Ser473) measured with Western blotting analysis. CONCLUSION: Overexpression of WWOX induces apoptosis and inhibits proliferation of the human hepatic carcinoma cell line SMMC-7721.

Matt＇s Initiation in a Dystopian World： Nancy Farmer＇s The House of the Scorpion

The House of the Scorpion （2002） is a National Book Award winner by American YA （young adult） novelist Nancy Farmer. It is a coming-of-age story about Matt, a young clone struggling for acceptance and survival in a dystopian world. Under the veil of science fiction, The House of the Scorpion not only allegorically exposes the evil of dehumanization, totalitarianism, and the abuse of technology, but also successfully builds up the brave image of Matt. Through depicting protagonist Matt＇s initiation journey in a dystopian world, Nancy Farmer expresses her belief that goodness triumphs and hope is indestructible.

Effects of monoclonal antibodies against human stathmin 1 combined paclitaxel on proliferation of human hepatocellular carcinoma cell lines

Objective： We investigated the effects of monoclonal antibodies against stathmin 1 combined paclitaxel on the proliferation of HCC cells. Methods： HepG2 cells were treated with monoclonal antibodies against stathmin 1, paclitaxel alone or their combination, with the untreated cells used as the control, 24, 48, 72, 96 h later, the cell growth condition was observed by invert microscope and inhabitation rate was studied by MTT assay; The apoptosis was analyzed by flow cytometry with Annexin V/PI. Results： The population decreased and shape, size changed after treating with different concentration of experimental groups. Monoclonal antibodies against stathmin 1 and paclitaxel used alone or in combination both inhibited the proliferation of HepG2 cells, the inhibition ratio of their combination was more higher （P 〈 0.05）, and a synergistic effect of the two agents was noted in their combined action （P 〈 0.05）. Combined treatment of the cells resulted in significantly higher apoptosis rate than that in the other groups （P 〈 0.05）. Conclusion： Monoclonal antibodies against stathmin 1 and paclitaxel used alone or in combination both can inhibit proliferation of HepG2 cells and induce apoptosis. A synergistic effect is obsewed between the monoclonal antibodies against stathmin 1 and paclitaxel in their inhibition of HepG2 cell proliferation.

Life in Kazuo Ishiguro＇s Never Let Me Go

With the announcement of the sheep clone Dolly as the breakthrough in the biotechnology in news media around the turn of the twenty-first century, the rising issue of human clones in its development and the controversially bioethical issues ensued, Kazuo Ishiguro in Never Let Me Go （2005） focuses his attention, in the area of cell therapy, on how human clones, since produced, lead their model lives and face their deaths, in order that his readers may better understand the meanings of life and death, and that they may stay in a far closer relationship with their family and friends than ever. In this essay, I examine, in two worlds, the normals＇ and the clones＇, paralleling each other, the true meanings of being human and their lives through the perspective of Jacques Derrida＇s deconstruction; and I argue that Ishiguro misspeaks to his readers the true meanings of life and death especially through the clones＇ perspective and brings them to his readers＇ hearts further realistically. In Derrida＇s nature-culture structurality of the clones, it is Kathy H. who comes as center into which the other clones come as freeplay in the structurality of the real world, where it is normals who come as center into which clones come as freeplay under the structurality of power in the institutions where the clones＇ culture comes as center into which Miss Emily＇s ruling comes as freeplay by the structurality of authorship where the author comes as center into which the novel comes as freeplay.

Expression of human acidic fibroblast growth factor in Pichia pastoris

Pichia pastoris expression system is similar to that of the mammal cell in modification of expressed protein, including refolding and glycosylation. A human aFGF gene was cloned into the intracellular expression vector pPIC9K. The Pichia pastoris KM71 strain was transformed with the recombined expression plasmid. Transgenic expression was observed after screening the transformants with G418. The expression and secretion of recombinant human aFGF (rhaFGF) into the culture medium were testified by ELISA assay. The yield peaked after two days of induction and was approximately 10 mgL-1 in shake-flask fermentation medium. The recombinant proteins were purified by the combination of heparin-Sepharose affinity chromatography and gel filtration chromatography. Two proteins with relative molecular masses (Mr) of 17 000 and 35 000 were purified as a single band in SDS-PAGE, whose biological activities were determined by MTT assay. It is found that the protein with Mr of 17 000 is nonglycosylated haFGF, and that with Mr of 35 000 is glycosylated haFGF; and the latter has a lower biological activity than the former.

αV integrin:A new gastrin target in human pancreatic cancer cells

AIM： To analyse αv integrin expression induced by gas- trin in pancreatic cancer models.METHODS： αv integrin mRNA expression in human pan- creatic cancer cells was analysed using a ＂cancer genes＂ array and confirmed by real-time reverse transcription- polymerase chain reaction （PCR）. Western blotting and semi-quantitative immunohistochemistry were used to examine protein levels in human pancreatic cancer cell lines and pancreatic tissues, respectively, The role of αv integrin on gastrin-induced cell adhesion was examined using blocking anti-αv integrin monoclonal antibodies. Adherent cells were quantified by staining with crystal violet.RESULTS： Using a ＂cancer genes＂ array we identi- fied c^v integrin as a new gastrin target gene in human pancreatic cancer cells. A quantitative real-time PCR approach was used to confirm αv integrin gene expression. We also demonstrate that Src family kinases and the PI 3-kinase, two signalling pathways specifically activated by the CCK-2 receptor （CCK2R）, are involved in gastrin-mediated αv integrin expression. In contrast, inhibition of the ERK pathway was without any effect on αv integrin expression induced by gastrin. Our results also show that gastrin modulates cell adhesion via αv integrins. Indeed, in vitro adhesion assays performed on fibronectin show that gastrin significantly increases adhesion of pancreatic cancer cells. The use of blocking anti-αv integrin monoclonal antibodies completely reversed the increase in cell-substrate adhesion induced by gastrin. In addition, we showed in vivo that the targeted CCK2R expression in the pancreas of Elas-CCK2 mice, leads to the overexpression of αv integrin. This process may contribute to pancreatic turnout development observed in these transgenic animals.CONCLUSION： αv integrin is a new gastrin target in pancreatic cancer models and contributes to gastrin effects on cell adhesion.

Genetic Diversity of Apple Cactus, Cereus peruvianus Mill. Clones （Cactaceae） and Its F1 Hybrids Using Random Amplified Polymorphic DNA in Indonesia

Polymorphism in two types of Cereus peruvianus, short and long spines clones, and its F1 hybrids cultivated in Indonesia were detected by RAPD （Random Amplified Polymorphic DNA） markers. High amount of mucilage （gelling polysaccharides） present in C. peruvianus was a major obstacle in isolating good quality genomic DNA. To obtain good quality DNA, the CTAB （Cetyl Trimethyl Ammonium Bromide） methode was modified. Out of 17 primers were used, and two primers OPN-05 and OPM-10 have specific loci, OPN-05550, OPN-05800 and OPM-10650, linked with spines types in parents clones. Those can be used as molecular marker for spines type. Seventeen primers were used generated 113 loci, of which 65 loci were polymorphic in parental clones and 132 loci, of which 93 loci were polymorphic in F1 plants. Dendrogram generated by Jaccard coefficient showed that parents＇ clones had lower genetic diversity than F1 plants. At 72% similarity, all of long or short spine parent clones grouped in one cluster according to its size of spines. At that time F1 plants were separately grouped. None ofF1 hybrid plants grouped with its common female parents.

Inhibitory effect of parvovirus H-1 on the formation of colonies of human hepatoma cell line in vitro and its tumors in nude mice

The inhibitory effect of parvovirus H-1 on the colonyforming ability in vitro of QGY-7703, a cultured human hepatoma cell line, and on the formation and growth of its tumors in nude mice was studied. With higher multiplicity of infection (MOI) of H-1 given, survival of the QGY-7703 cells was found to be decreased. H-1 DNA amplification level at 30 h postinfection(p.i.) was detected to be 7.4 times higher than that at 2 h by dispersed cells assay, while the cells were delayed to enter into S phase.Plaques were formed in the indicator cells (new-born human kidney cell line, NBK) by progeny H-1 virus particles released from the infected QGY-7703 cells by infectious cell center assay. The formation of tumors in nude mice by QGY-7703 cells which were injected s c at 2 h postinfection was observed to be prevented in 2 groups with given MOI 25 and 50. The tumor growth of MOI 10 group occurred at a lower exponential rate than that of control,after a 20 d latent period. It was evident that parvovirus H-1 exhibited a direct inhibitory effect on the formation and growth of human hepatoma cells in vivo as well as in vitro.

Inbreeding and genetic diversity analysis in a hatchery release population and clones of Rhopilema esculentum based on microsatellite markers

Ten microsatellite markers were used to analyze the levels of genetic diversity and inbreeding in a hatchery release population of Rhopilema esculentum Kishinouye （Scypbozoa： Rhizostomatidae）. A total of 85 alleles were detected in 600 individuals. Within-population levels of observed （Ho） and expected （He） heterozygosity ranged from 0.152 to 0.839 （mean=0.464） and from 0.235 to 0.821 （mean=0.618）, respectively. The polymorphism information content （PIC） of each marker ranged from 0.207 to 0.795 with an average of 0.580, indicating that the hatchery population maintained a high level of genetic diversity. Inbreeding levels were estimated in the hatchery population and the inbreeding coefficient was 0.203. This result revealed that a certain level of inbreeding occurred within the population. Meanwhile, we also determined genetic diversity at the clone level. Several polyps from the same scyphistomae were genotyped at the ten microsatellite loci and there was virtually no difference in their genotypes. Furthermore, we calculated the probabilities of exclusion. When both parents were known, the average exclusion probability often loci was 99.99%. Our data suggest that the ten microsatellite markers can not only be used to analyze the identity of individuals but they can also be applied to parentage identification. Our research provides a theoretical basis and technical support for genetic diversity detection and reasonable selection of R. esculentum hatchery populations. These findings support the use of releasing studies and conservation of R. esculentum germplasm resources.

Cloning and expression of special F protein from human liver

AIM： To clone human liver special F protein and to express it in a prokaryotic system. METHODS： Total RNA was isolated from human liver tissue and first-strand cDNA was reverse transcribed using the PCR reverse primer. Following this, cDNA of the F protein was ligated into the clone vector pUCm-T. The segment of F protein＇s cDNA was subdoned into the expression vector pET-15b and transformed into E. coli BL21 （DE3） pLyss. Isopropy-β-D-thiogalactoside （IPTG） was then used to induce expression of the target protein. RESULTS： The cDNA clone of human liver special F protein （1134bp） was successfully produced, with the cDNA sequence being published in Gene-bank： DQ188836. We confirmed the expression of F protein by Western blot with a molecular weight of 43 kDa. The expressed protein accounted for 40% of the total protein extracted. CONCLUSION： F protein expresses cDNA clone in a prokaryotic system, which offers a relatively simple way of producing sufficient quantities of F protein and contributes to understanding the principal biological functions of this protein.

Correlativity of lymph node micrometastases detection in follicular carcinoma of thyroid in different risk groups

Objective:The aim of this study was to explore the relationship between follicular carcinoma of thyroid in different risk groups and lymph node micrometastases.Methods:The keratin-19 of negative neck lymph nodes in 83 cases in routine pathological examination,was detected by SP immunohistochemistry using keratin-19 monoclonal antibody to confirm lymph node micrometastases.All of cases are divided into high risk group,middle risk group and low risk group according to factors related prognosis,the relationship between lymph node micrometastases and different risk groups and follow-up visit documents were analyzed.Results:Fifty-eight neck lymph nodes in 16 cases of 83 cases(19.3%) showed positive lymph node micrometastases,and incidence of lymph node micrometastases was 4/39 in low risk group,5/32 in middle risk group and 7/12 in high risk group,respectively.it showed remarkable difference during 3 groups(P < 0.001).Nine patients in 16 cases with positive lymph node micrometastases showed local recurrence and distant metastases,6 patients in 67 cases with negative lymph node micrometastases showed same result(P < 0.001).Conclusion:Lymph node micrometastases in follicular thyroid carcinoma closely correlated to factors related to prognosis.The detection of lymph node micrometastases can directly assistant postoperative treatment and prognosis evaluation to some extent for follicular thyroid carcinoma.

Cloning,expression and function of the extracellular fragment of human TRAIL gene

To obtain the recombinant soluble protein of the extracellular fragment of human TRAIL gene and to identify its function preliminarily, this gene fragment was amplified from peripheral blood mononuclear cells （PBMC） by RT-PCR and cloned into vector pGEM-T-Easy for sequence analysis. The expression vector pET-30a/TRAIL was then constructed by DNA recombination method with a His-tag gene at the front of the TRAIL fragment, and the recombinant protein was expressed in E. coli BL21 （DE3）. Meanwhile, the expressed target protein was purified with Ni-NTA chromatography column and identified by SDS-PAGE and Western blotting. The proliferation inhibition activity of TRAIL-His was detected by MTF assay. PI staining and Wright-Giemsa staining were used to detect the presence of the TRAIL-induced cell apoptosis. It was demonstrated that the target protein expressed in E. coli BL21 showed the same relative molecular mass as that the protein expected and could be recognized by both the anti-TRAIL polyclonal antibody and anti-His monoclonal antibody. In addition, this protein could also inhibit proliferation of human lymphoma cell line Jurkat cells or induce apoptosis of this cell line. It is apparent that a recombinant soluble TRAIL protein with biological activity is obtained and this prospective study can lay solid foundation for further research on the biological activity and application in the anti-tumor therapy.

Human Monoclonal Antibodies as Candidate Therapeutics Against Emerging Viruses and HIV-1

More than 40 monoclonal antibodies (mAbs) have been approved for a number of disease indications with only one of these (Synagis) - for a viral disease, and not for therapy but for prevention. However, in the last decade novel potent mAbs have been discovered and characterized with potential as therapeutics against viruses of major importance for public health and biosecurity including Hendra virus (HeV), Nipah virus (NiV), severe acute respiratory syndrome coronavirus (SARS-CoV), Ebola virus (EBOV), West Nile virus (WNV), influenza virus (IFV) and human immunodeficiency virus type 1 (HIV-1). Here, we review such mAbs with an emphasis on antibodies of human origin, and highlight recent results as well as technologies and mechanisms related to their potential as therapeutics.

PREPARATION AND CHARACTERIZATION OF MONOCLONAL ANTIBODY AGAINST HUMAN TELOME RASE REVERSE TRANSCRIPTASE

Objective.To develop monoclonal antibodies again st the catalytic subunit of human telomerase reverse transcriptasefor i ts expression detection of human tumors.Methods.A dominant epitope in hTERT was automatically synthesized based on Fmoc method,and was used to immuni ze Balb/c mice.Hybridomas were generated and screened by ELISA for specific mo noclonal antibodies,and the characterization was performed by Western blotting and immunohistochemical staining.The heavy chain variable region of antibody wa s cloned by RT-PCR and sequenced.Results.Antigenic peptide hTERT 7 was synthesized and confirmed by MALDI-TOF-MS and HPLC analysis.One hybr idoma cell line secreting anti-hTERT 7 antibodies designated as M2was established after primary screening and cons equent 3rounds of limited dilution.M2was IgG1in isotyping.The competi-tive assay showed that the M2antibody was hTERT 7-specific,and the affinity constant was about 1×10 6 mol-1 .The antibody reacted with cell extracts from HeLa cancer cells but not wi th those from normal2BS cells in ELISA assay.For in situ staining of immunohis tochemistry,the positive staining presented in the nuclear compartment of HeLa ,while2BS was negative.The heavy chain variable region from M2re-vealed tha t the monoclonal antibody was mouse origin.Conclusions.The developed mouse mon oclonal antibody is hTERT-specific and able to recognize native cellular hTERT in ELISA and immunohistochemistry,which makes the immuno-detection of telom-e rase hTERT expression in cancer cells or tissues possible.