胃肠道间质瘤组织中MMP-13与CD147的表达及其意义

目的探讨基质金属蛋白酶-13（Matrix metalloproteinases-13,MMP-13）和CD147的表达与胃肠道间质瘤（Gastrointestinals stromal tumors,GISTs）临床病理特征的关系。方法采用免疫组织化学检测69例GISTs组织中MMP-13及CD147的表达,分析MMP-13和CD147与各病理参数的关系。结果GISTs组织中MMP-13和CD147的表达率分别为95.7%和97.1%,MMP-13阳性表达程度与GISTs的生物学行为、CD147表达及肿瘤的大小呈正相关（P〈0.05）;CD147阳性表达程度与肿瘤的大小呈正相关（P〈0.05）。结论MMP-13表达与GISTs生物学行为关系密切,可作为GISTs生物学行为的潜在评价指标。     

The feasibility of using a two-stage autotrophic nitrogen removal process to treat sewage

The feasibility of using a two-stage autotrophic nitrogen removal process to treat sewage was examined in this study. The obtained results showed that total nitrogen (TN) could be efficiently removed by 88.38% when influent TN and chemical oxygen demand (COD) were 45.87 and 44.40 mg/L, respectively. In the first stage, nitritation was instantly achieved by the bioaugmentation strategy, and can be maintained under limited oxygen condition (below 0.2mg/L). The ratio of nitrite to ammonium in the effluent of the nitritation reactor can be controlled at approximate 1.0 by adjusting aeration rate. In the second stage, anammox was realized in the upflow anaerobic sludge blanket (UASB) reactor, where the total nitrogen removal rate was 0.40 kg Nm(-3)d(-1) under limited-substrate condition. Therefore, the organic matter in sewage can be firstly concentrated in biomass which could generate biogas (energy). Then, nitrogen in sewage could be removed in a two-stage autotrophic nitrogen removal process.     

Mechanisms of mucosal and parenteral tuberculosis vaccinations: adenoviral-based mucosal immunization preferentially elicits sustained accumulation of immune protective CD4 and CD8 T cells within the airway lumen

The mechanisms underlying better immune protection by mucosal vaccination have remained poorly understood. In our current study we have investigated the mechanisms by which respiratory virus-mediated mucosal vaccination provides remarkably better immune protection against pulmonary tuberculosis than parenteral vaccination. A recombinant adenovirus-based tuberculosis (TB) vaccine expressing Mycobacterium tuberculosis Ag85A (AdAg85A) was administered either intranasally (i.n.) or i.m. to mice, and Ag-specific CD4 and CD8 T cell responses, including frequency, IFN-gamma production, and CTL, were examined in the spleen, lung interstitium, and airway lumen. Although i.m. immunization with AdAg85A led to activation of T cells, particularly CD8 T cells, in the spleen and, to a lesser extent, in the lung interstitium, it failed to elicit any T cell response in the airway lumen. In contrast, although i.n. immunization failed to effectively activate T cells in the spleen, it uniquely elicited higher numbers of Ag-specific CD4 and CD8 T cells in the airway lumen that were capable of IFN-gamma production and cytolytic activities, as assessed by an intratracheal in vivo CTL assay. These airway luminal T cells of i.n. immunized mice or splenic T cells of i.m. immunized mice, upon transfer locally to the lungs of naive SCID mice, conferred immune protection against M. tuberculosis challenge. Our study has demonstrated that the airway luminal T cell population plays an important role in immune protection against pulmonary TB, thus providing mechanistic insights into the superior immune protection conferred by respiratory mucosal TB vaccination.     

FLP recombinase-mediated site-specific recombination in silkworm, Bombyx mori

A comprehensive understanding of gene function and the production of site-specific genetically modified mutants are two major goals of genetic engineering in the post-genomic era. Although site-specific recombination systems have been powerful tools for genome manipulation of many organisms, they have not yet been established for use in the manipulation of the silkworm Bombyx mori genome. In this study, we achieved site-specific excision of a target gene at predefined chromosomal sites in the silkworm using a FLP/FRT site-specific recombination system. We first constructed two stable transgenic target silkworm strains that both contain a single copy of the transgene construct comprising a target gene expression cassette flanked by FRT sites. Using pre-blastoderm microinjection of a FLP recombinase helper expression vector, 32 G3 site-specific recombinant transgenic individuals were isolated from five of 143 broods. The average frequency of FLP recombinase-mediated site-specific excision in the two target strains genome was approximately 3.5%. This study shows that it is feasible to achieve site-specific recombination in silkworms using the FLP/FRT system. We conclude that the FLP/FRT system is a useful tool for genome manipulation in the silkworm. Furthermore, this is the first reported use of the FLP/FRT system for the genetic manipulation of a lepidopteran genome and thus provides a useful reference for the establishment of genome manipulation technologies in other lepidopteran species.     

Separation,antitumor activities,and encapsulation of polypeptide from Chlorella pyrenoidosa

Chlorella pyrenoidosa is a unicellular green algae and has been a popular foodstuff worldwide. However, no reports on the antitumor peptides from such a microalgae are available in the literature. In this study, using low‐temperature high‐pressure extraction, enzymatic hydrolysis, ion exchange, and gel filtration chromatography, we separated a polypeptide that exhibited inhibitory activity on human liver cancer HepG2 cells, and named the polypeptide CPAP (C. pyrenoidosa antitumor polypeptide). Furthermore, the micro‐ and nanoencapsulation of CPAP were investigated by using two methods: complex coacervation and ionotropic gelation. The in vitro release tests revealed that CPAP was well preserved against gastric enzymatic degradation after micro/nanoencapsulation and the slowly controlled release in the intestine could be potentially achieved. These results suggest that CPAP may be a useful ingredient in food, nutraceutical, and pharmaceutical applications. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:681–687, 2013     

Rapid amplification and cloning of Tn5 flanking fragments by inverse PCR

A simple approach is described to efficiently amplify DNA sequences flanking transposon Tn5 insertions. The method involves: (i) digestion with a restriction enzyme that cuts within Tn5; (ii) self-ligation under conditions favouring the production of monomeric circles; (iii) four parallel PCR reactions using primers designed to amplify left or right flanking sequences, and to distinguish target amplicons from non-specific products. This reveals the number of Tn5 insertions and the size of flanking genomic restriction fragments, without Southern blot analysis. The amplified product contains restriction sites that facilitate cohesive-end cloning. This rapid method is demonstrated using Tn5 and Tn5-Mob tagged DNA sequences involved in albicidin biosynthesis in Xanthomonas albilineans. It is generally applicable for efficient recovery of DNA sequences flanking transposon Tn5 derivatives in insertional mutagenesis studies.     

产生物表面活性剂芽孢杆菌培养条件的优化

为了提高生物表面活性剂的表面活性,通过单因素及正交试验对已筛选的产生物表面活性剂芽孢杆菌的培养基及培养条件进行了优化,优化后的培养基成分为可溶性淀粉20 g/L,氯化铵2 g/L,KH2PO46 g/L,K2HPO42 g/L,MgSO4.7H2O 0.3 g/L,NaCl 2 g/L,CaCl20.08 g/L,EDTA 0.4 g/L。培养条件为4%接种量,种龄16 h,初始pH7,培养温度37℃,摇床转速160 r/min,发酵48 h。优化发酵条件后,发酵液表面张力由初始67.5 mN/m降低至24.8 mN/m,生物表面活性剂产量达到1.08 g/L。     

1α羟化酶活性和血钙水平对24羟化酶基因表达的影响

目的:研究肾脏24羟化酶基因表达的影响因素。方法:采用两种基因敲除小鼠。每种小鼠又分两种饲养方式。用生化分析仪测定小鼠血钙浓度。用半定量RT-PCR法研究小鼠肾脏组织中1α羟化酶和24羟化酶基因的表达。结果:1α羟化酶基因敲除小鼠体内血钙低于野生型小鼠(78±10.4 mg/Lvs111±16.5 mg/L,P<0.05.),测不出24羟化酶基因表达。维生素D受体基因敲除小鼠有很高的1α羟化酶表达,小鼠血钙也显著低于野生型小鼠(68±9.8 mg/Lvs111±16.5 mg/L,P<0.05),测不出24羟化酶表达。但给予高乳糖饲料后,两种基因敲除小鼠血钙都上升到与野生型小鼠一致水平。此时,24羟化酶基因的表达与野生型也基本一致。结论:血钙是调节24羟化酶基因表达的直接因素,1α羟化酶对24羟化酶的正向调节作用是通过升高血钙来实现的。