Effects of different chemotherapeutic agents on reversing the acquired resistance to TRAIL gene in DLD1 colon cancer cells

AIM:To evaluate effects of different chemotherapeutic agents on reversing the acquired resistance to TRAIL gene and clarify the involved mechanisms in DLD1-TRAIL/R colon cancer cells. METHODS:Human colon cancer cell line DLD1-TRAIL/R cells that were resistant to TRAIL-expressing adenovector (Ad/gTRAIL) were treated with Ad/gTRAIL combined with different chemotherapeutic agents. Then, the cell viability was measured by MTT method, and apoptotic signaling conditions, including activation of caspase-3 and caspase-8, expression of Bax and Bcl-XL, were measured by Western blotting analysis. RESULTS:In vitro data showed that several chemotherapeutic agents, including 5-fluorouracil (5-FU) and mitomycin c (MMC), overcome the acquired resistance to TRAIL gene in DLD1-TRAIL/R colon cancer cells. The combination of Ad/gTRAIL and 5-FU effectively suppressed tumor growth in vivo in subcutaneous tumors established from DLD1-TRAIL/R cells. Further data showed that treatment with the combination of Ad/gTRAIL and 5-FU or MMC led to enhance the activation of caspase-3. Moreover, MMC but not 5-FU induced overexpression of Bax gene that was sufficient to overcome the resistance to TRAIL gene in DLD1-TRAIL/R cells. CONCLUSION:Chemotherapeutic agents, such as 5-FU and MMC, overcome the acquired resistance to TRAIL gene in DLD1-TRAIL/R cells. The candidate mechanisms for MMC but not 5-FU to overcome this resistance might involve the induction of over-expressed Bax protein in DLD1-TRAIL/R cells.     

Molecular, physiological and pathological characterization of Corynespora leaf spot fungi from rubber plantations in Sri Lanka

The plant pathogenic fungus Corynespora cassiicola causes a severe leaf spot disease on more than 70 host plant species including Hevea brasiliensis . Genetic variability in 32 isolates of C. cassiicola collected from diverse hosts and locations in Sri Lanka and Australia was assessed using restriction fragment length polymorphism (RFLP) analysis of the internal transcribed spacer (ITS) region of ribosomal DNA and random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) analysis of total fungal DNA. Amplified ITS fragments from all 32 C. cassiicola isolates exhibited an identical size, and restriction analysis with seven different restriction endonucleases revealed identity in all of the detected DNA fragments. This finding of high genetic relatedness was further supported by the cloning and DNA sequencing of the ITS2 region from one Sri Lankan and one Australian isolate. However, RAPD-PCR profiles generated by 15 oligonucleotide decamer primers revealed significant polymorphism between groups of organisms. Genetic relationships among the isolates were determined by cluster analysis of the RAPD-PCR data and seven different RAPD groups were identified. Isolates showed strong correlations between the assigned RAPD group and the location and host plant genotype from which the isolate was collected. Correlations were also observed between the RAPD group, growth of the isolate and pathogenicity on different plant hosts.     

Biological control ofBotrytis cinerea in residues and flowers of Rose (Rosa hybrida)

Microbial isolates from living petals, petal residues and leaf residues of rose, and from laboratory collections, were evaluated for control ofBotrytis cinerea in rose. In leaf residues artificially infested withB. cinerea, isolates of the filamentous fungiGliocladium roseum, FR136 (unidentified) andTrichoderma inhamatum reduced sporulation of the pathogen by >90%, other filamentous fungi were 25–90% effective, and those of yeasts and bacteria were <50% effective. In artificially inoculated petal residues, no microbe reduced sporulation ofB. cinerea by >75%, but isolates ofCladosporium oxysporum and four yeasts were 51–75% effective, and three filamentous fungi, eight yeasts andBacillus subtilis isolates were 26–50% effective. Isolates ofT. inhamatum, C. oxysporum andG. roseum performed best againstB. cinerea among isolates evaluated in leaf residues naturally infested with the pathogen and indigenous microorganisms. Totals of ten isolates of filamentous fungi (includingC. oxysporum andC. cladosporioides), two of yeasts and five ofBacillus subtilis completely prevented lesion production byB. cinerea in detached petals, and a further six isolates of filamentous fungi (includingG. roseum) and six yeasts were 90–99% effective. Isolates ofC. oxysporum, C. cladosporioides andB. subtilis, the most effective microorganisms againstB. cinerea in flower buds, reduced number of lesions in the range of 42–65% compared with 59–89% for à standard fungicide (vinclozolin). It is suggested that application of leading antagonists Jo living rose leaves and flowers should optimize control of inoculum production byB. cinerea when the tissues die. Optimal biocontrol of lesion production in flower buds requires a better understanding of the microenvironment of petals.     

成功的启示——南京奶业(集团)公司经营分析

南京奶业 (集团 )公司扭亏为盈 ,并取得骄人业绩的启示是 :企业正确定位 ;实行企业 (集团 )经营的公司型运作方式 ;实行低成本扩张和品牌战略 ;引进国外先进技术设备 ,走与国际奶业接轨的发展道路 ;改善产业结构 ,实行多元化经营。     

Use of ELISA for detection of immunoglobulins G and M that recognize Salmonella dublin lipopolysaccharide for prediction of carrier status in cattle

Immunoglobulin reactions to Salmonella dublin in serum and milk from 4 groups of lactating cows were measured by an indirect ELISA. The groups consisted of (1) cows that were natural carriers of S dublin in the mammary gland, (2) experimentally infected cows that did not become carriers, (3) cows inoculated with a commercial S dublin bacterin, and (4) cows used as S dublin-negative controls. Milk and serum samples were obtained at monthly intervals. Models for predicting carrier status were developed by use of stepwise logistic regression. Independent variables consisted of serum and milk IgG and IgM titers to S dublin lipopolysaccharide and a ratio of IgG to IgM. The utility of a single sample vs multiple samples obtained at 1-month or 2-month intervals was tested by comparison of goodness-of-fit chi 2 P values for 8 models predicting carrier status. Immunoglobulin reactions specific to S dublin were a significant predictor of carrier status (P less than 0.001). Serum IgG titers specific for S dublin were the most important variable for predicting carrier status. Two serum IgG titers to S dublin obtained 2 months apart was a better predictor of carrier status than measurement of the IgG:IgM ratio from a single serum sample. Immunoglobulin recognizing S dublin epitopes also were detected in milk samples. In milk, performing 2 ELISA 60 days apart to determine IgG and IgM reactions to S dublin appeared to be useful for the prediction of carrier status, but was not as accurate as models for serum immunoglobulin reactions.     

TCP/IP协议脆弱性分析

TCP/IP协议是网络发展的一个基础，但是该协议确存在着致命的弱点，盲目的使用与该协议相关的服务或应用会给网络安全带来隐患，认识到TCP/IP协议的脆弱性进对我们加强网络管理和采用安全技术手段具有指导性作用。     

Dynamics of natural infection by Toxoplasma gondii in goat herds in the semiarid region of northeastern Brazil: transitional antibody observation

Veterinary Research Communications - This study aimed to describe the transmission of T. gondii in naturally infected goats in the semiarid region of northeastern Brazil, through evaluating the...     

巨尾桉瓶内菌根化组培苗的造林效应

1993～ 1994年 ,在广东省开平市国营镇海林场建立了 2个巨尾桉组培苗瓶内接种外生菌根菌的野外造林试验。 2个试验中 ,共采用 17个外生菌根菌菌株。造林后定期观测了 12或 2 4个月树高、地径和胸径等生长指标。试验结果表明 :除试验 2造林初期的树高外 ,其他所有生长指标在菌根菌处理间均有极显著差异或显著差异 ,菌根菌间对巨尾桉生长有不同的影响 ;从多重比较和接种效果分析看 ,菌株E4 0 70、H4 5 0 9、E4 2 4 0、H6 177、H4 339、E4 72 6、C930 1、C92 13和C92 0 3,在造林后 6个月开始可明显地促进巨尾桉树木生长 ,说明组培苗瓶内菌根化技术是完全可行的 ,有关菌株对巨尾桉幼树生长具有促进作用     

变频调速技术在供热锅炉房中的应用

本文介绍了变频调速技术的特点,通过锅炉房风机和水泵的变频调速与挡板节流控制及其它控制方式的比较可知,变频调速有较好的节能效果。