Linkages of soil CO2 emission with plant functional traits in young subtropical plantations.

Soil respiration is a key process in forest biogeochemical cycling. Exploring the relationship between plant functional traits and soil respiration can help understand the effects of tree species conversion on soil carbon cycling. In this study, we selected 15 common subtropical tree species planted in the logging site of second-generation Chinese fir forest to measure soil CO2 emission fluxes, soil physicochemical properties, leaf and root functional traits of each species, and explored the effects of plant functional traits on soil respiration. The results showed that the annual flux of soil CO2 emissions varied from 7.93 to 22.52 Mg CO2·hm-2, with the highest value under Castanopsis carlesii (22.52 Mg CO2·hm-2) and the lowest value under Taxus wallichiana (7.93 Mg CO2·hm-2). Results of stepwise regression analysis showed that the annual flux of soil CO2 emission decreased with the increases of leaf nitrogen content and fine root diameter, and increased with increasing leaf non-structural carbohydrate. In the structural equation model, leaf non-structural carbohydrate had a direct and significant positive effect on soil CO2 emission fluxes, while leaf nitrogen content and fine root diameter had a direct negative effect by decreasing soil pH and soluble organic nitrogen content. Plantations of different tree species would affect soil CO2 emission directly by changing functional traits related to water and nutrient acquisition or indirectly through soil properties. When creating plantations, we should select tree species based on the relationship between plant functional traits and ecosystem functions, with a view to improving forest productivity and soil carbon sequestration potential.

A novel strategy to control Pseudomonas syringae through inhibition of type III secretion system.

Pseudomonas syringae (P. syringae) is a highly prevalent Gram-negative pathogen with over 60 pathogenic variants that cause yield losses of up to 80% in various crops. Traditional control methods mainly involve the application of antibiotics to inactivate pathogenic bacteria, but large-scale application of antibiotics has led to the development of bacterial resistance. Gram-negative pathogens including P. syringae commonly use the type III secretion system (T3SS) as a transport channel to deliver effector proteins into host cells, disrupting host defences and facilitating virulence, providing a novel target for antibacterial drug development. In this study, we constructed a high-throughput screening reporter system based on our previous work to screen for imidazole, oxazole and thiazole compounds. The screening indicated that the three compounds (II-14, II-15 and II-24) significantly inhibited hrpW and hrpL gene promoter activity without influencing the growth of P. syringae, and the inhibitory activity was better than that of the positive control sulforaphane (4-methylsulfinylbutyl isothiocyanate, SFN) at 50 µM. Three compounds suppressed the transcript levels of representative T3SS genes to different degrees, suggesting that the compounds may suppress the expression of T3SS by modulating the HrpR/S-HrpL regulatory pathway. Inoculation experiments indicated that all three compounds suppressed the pathogenicity of Pseudomonas syringae pv. tomato DC3000 in tomato and Pseudomonas syringae pv. phaseolicola 1448A in bean to varying degrees. One representative compound, II-15, significantly inhibited the secretion of the Pst DC3000 AvrPto effector protein. These findings provide a theoretical basis for the development of novel P. syringae T3SS inhibitors for application in disease prevention and control.

O6-methylguanine DNA methyltransferase is upregulated in malignant transformation of gastric epithelial cells via its gene promoter DNA hypomethylation.

BACKGROUND: O6-methylguanine-DNA methyltransferase (MGMT) is a suicide enzyme that repairs the mispairing base O6-methyl-guanine induced by environmental and experimental carcinogens. It can transfer the alkyl group to a cysteine residue in its active site and became inactive. The chemical carcinogen N-nitroso compounds (NOCs) can directly bind to the DNA and induce the O6-methylguanine adducts, which is an important cause of gene mutation and tumorigenesis. However, the underlying regulatory mechanism of MGMT involved in NOCs-induced tumorigenesis, especially in the initiation phase, remains largely unclear. AIM: To investigate the molecular regulatory mechanism of MGMT in NOCs-induced gastric cell malignant transformation and tumorigenesis. METHODS: We established a gastric epithelial cell malignant transformation model induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or N-methyl-N-nitroso-urea (MNU) treatment. Cell proliferation, colony formation, soft agar, cell migration, and xenograft assays were used to verify the malignant phenotype. By using quantitative real-time polymerase chain reaction (qPCR) and Western blot analysis, we detected the MGMT expression in malignant transformed cells. We also confirmed the MGMT expression in early stage gastric tumor tissues by qPCR and immunohistochemistry. MGMT gene promoter DNA methylation level was analyzed by methylation-specific PCR and bisulfite sequencing PCR. The role of MGMT in cell malignant transformation was analyzed by colony formation and soft agar assays. RESULTS: We observed a constant increase in MGMT mRNA and protein expression in gastric epithelial cell malignant transformation induced by MNNG or MNU treatment. Moreover, we found a reduction of MGMT gene promoter methylation level by methylation-specific PCR and bisulfite sequencing PCR in MNNG/MNU-treated cells. Inhibition of the MGMT expression by O6-benzylguanine promoted the MNNG/MNU-induced malignant phenotypes. Overexpression of MGMT partially reversed the cell malignant transformation process induced by MNNG/MNU. Clinical gastric tissue analysis showed that MGMT was upregulated in the precancerous lesions and metaplasia tissues, but downregulated in the gastric cancer tissues. CONCLUSION: Our finding indicated that MGMT upregulation is induced via its DNA promoter hypomethylation. The highly expressed MGMT prevents the NOCs-induced cell malignant transformation and tumorigenesis, which suggests a potential novel approach for chemical carcinogenesis intervention by regulating aberrant epigenetic mechanisms.

Discovery of a series of 5-phenyl-2-furan derivatives containing 1,3-thiazole moiety as potent Escherichia coli ß-glucuronidase inhibitors.

Gut microbial ß-glucuronidases have drawn much attention due to their role as a potential therapeutic target to alleviate some drugs or their metabolites-induced gastrointestinal toxicity. In this study, fifteen 5-phenyl-2-furan derivatives containing 1,3-thiazole moiety (1-15) were synthesized and evaluated for their inhibitory effects against Escherichia coli ß-glucuronidase (EcGUS). Twelve of them showed satisfactory inhibition against EcGUS with IC50 values ranging from 0.25 µM to 2.13 µM with compound 12 exhibited the best inhibition. Inhibition kinetics studies indicated that compound 12 (Ki = 0.14 ± 0.01 µM) was an uncompetitive inhibitor for EcGUS and molecular docking simulation further predicted the binding model and capability of compound 12 with EcGUS. A preliminary structure-inhibitory activity relationship study revealed that the heterocyclic backbone and bromine substitution of benzene may be essential for inhibition against EcGUS. The compounds have the potential to be applied in drug-induced gastrointestinal toxicity and the findings would help researchers to design and develop more effective 5-phenyl-2-furan type EcGUS inhibitors.

Meta-analysis of the effects of liming on soil pH and cadmium accumulation in crops.

Increasing cadmium (Cd) contamination in agricultural fields has resulted in a higher risk of Cd accumulation in the food chain. Lime addition can mitigate soil acidification and reduce Cd accumulation in crops cultured in Cd-contaminated soil. To determine key factors controlling the outcomes of liming in reducing Cd accumulation and enhancing soil pH, we performed a meta-analysis using previously published data from field and pot experiments. The results indicated that the liming showed positive effect sizes on the soil pH but negative effect sizes on Cd accumulation in crops, indicating the addition of different lime materials could enhance soil pH and reduce Cd accumulation in crops. The effect sizes of liming on soil pH under pot experimental conditions were higher than that under field experimental conditions, however, the effect sizes of application types and amount of limes on soil pH did not significantly differ between their individual different levels. Under a low background value of soil pH, SOM, CEC and clay, the addition of limes showed a significantly higher effect size on soil pH when compared to their individual higher soil background value, suggesting that the lower background values of soil pH, SOM, CEC and clay might facilitate the outcomes of liming to enhance soil pH. The experiment patterns, crop types and lime application amounts showed a limit effect on the outcomes of liming to reduce the shoot and grain Cd concentrations in crops. The lime types only showed a significant effect size on the shoot Cd accumulation but not on the grain Cd accumulation, in which the CaCO3 had the highest effect size (absolute value, the same below) followed by Ca(OH)2 and CaO. The low soil background values of total Cd concentration and CEC content, but a high soil SOM background content might facilitate the outcomes of liming to reduce the shoot Cd concentration in crops. However, only the background value of soil clay content showed a significantly negative effect size on the grain Cd accumulation, where a high soil clay content had a higher effect size than a low soil clay content. These findings provide useful knowledge about the effects of experiment patterns, crop types, soil conditions, lime types and lime addition amounts on the efficiency of liming in enhancing soil pH and decrease crop Cd concentration.

Identification of critical genes associated with the development of asthma by co-expression modules construction.

INTRODUCTION: Asthma is a worldwide problem that is caused by complex underlying immune dysregulation. The identification of potential prognostic markers of asthma may provide information for treatment. The purpose of this study was to explore the key mechanisms involved in the development of asthma on the basis of microarray analysis. METHODS: The expression profile data of GSE43696, which contains 20 endobronchial epithelial brushing samples from healthy patients and 88 from asthma patients, were obtained from Gene Expression Omnibus. For the present study, we built co-expression modules by weighted gene co-expression network analysis (WGCNA). This new analysis strategy was applied to the data set to investigate the relationships underlying the modules and the pathogenesis of asthma. Functional enrichment analysis was performed on these co-expression genes from the modules, and a gene network was then constructed. In addition, mouse models of HDM-induced and OVA-induced asthma were established, and the expression of hub genes was measured. RESULTS: First, using WGCNA, 20 co-expression modules were constructed with 19,596 genes obtained from 108 human endobronchial epithelial brushing samples. The number of genes within the modules ranged from 41 to 845. According to the colours assigned by the system, the module positively correlated with asthma status was named 'red module', and the module positively correlated with asthma severity was named 'purple module'. The results of a functional enrichment analysis showed that the red module was mainly enriched in intracellular calcium-activated chloride channel activity, intracellular chloride channel activity and endopeptidase inhibitor activity. The purple module was mainly enriched in microtubule motor activity and microtubule-binding and motor activity. Moreover, the mRNA expression levels of the 15 hub genes were confirmed to be significantly upregulated in the HDM mouse model, and 12 hub genes were upregulated in the OVA model. CONCLUSIONS: The hub genes ANO7, PYCR1 and UBE2C might play potential roles in the pathogenesis of asthma. Our findings provided a framework of co-expression gene modules of asthma and led to the identification of some new markers that might be potential targets for the development of new drugs and diagnostic markers.

[Nutrient Distribution of Overlying Water in Tidal Marshes in Five Estuaries and Bays of the Fuzhou Region in Autumn].

Overlying water from the tidal marshes in five estuaries and bays, namely, Xinghua Bay (Fuzhou Part), Fuqing Bay, Luoyuan Bay, Minjiang River Estuary, and Aojiang River Estuary of the Fuzhou region were collected in autumn of 2015, and the nitrogen and phosphorus nutrient concentration and other physical and chemical indicators of the overlying water were measured to discuss the reasons for the differences in the nutrient concentration of the overlying water in tidal marsh wetlands in different bays and estuaries. There were significant differences in the nitrogen and phosphorus nutrient concentrations of the overlying waters of the tidal marshes in the different bays and estuaries (P<0.05). The concentrations of nitrogen and phosphorus in Fuqing Bay were relatively high, while Xinghua Bay had the lowest nitrogen nutrient concentration and Aojiang River Estuary had the lowest phosphorus nutrient concentration. The nutrient concentration of the overlying water in Fuqing Bay is mainly affected by regional aquaculture, land-source pollution, and topography, while that in Xinghua Bay is mainly affected by tides. The vegetation type had an effect on the nutrient concentration of the overlying water in the wetlands. The concentration of nitrogenous nutrients in the overlying water of the marsh wetland in the Suaeda australis community was relatively high, while the nitrogen and phosphorus nutrient concentrations in the overlying water of the Spartina alterniflora community wetland was relatively low; the concentrations of nutrients in the overlying water of different plant communities in the same bay or estuary marsh wetland were different, and the relationships were complex. Tides, surface runoff, plant communities, topography, and human activities all had an important impact on the nutrient concentrations in the overlying waters of the bay and estuary wetlands.

Endothelial cell-specific anticoagulation reduces inflammation in a mouse model of acute lung injury.

Tissue factor (TF)-dependent coagulation contributes to lung inflammation and the pathogenesis of acute lung injury (ALI). In this study, we explored the roles of targeted endothelial anticoagulation in ALI using two strains of transgenic mice expressing either a membrane-tethered human tissue factor pathway inhibitor (hTFPI) or hirudin fusion protein on CD31+ cells, including vascular endothelial cells (ECs). ALI was induced by intratracheal injection of LPS, and after 24 h the expression of TF and protease-activated receptors (PARs) on EC in lungs were assessed, alongside the extent of inflammation and injury. The expression of TF and PARs on the EC in lungs was upregulated after ALI. In the two strains of transgenic mice, expression of either of hTFPI or hirudin by EC was associated with significant reduction of inflammation, as assessed by the extent of leukocyte infiltration or the levels of proinflammatory cytokines, and promoted survival after LPS-induced ALI. The beneficial outcomes were associated with inhibition of the expression of chemokine CCL2 in lung tissues. The protection observed in the CD31-TFPI-transgenic strain was abolished by injection of an anti-hTFPI antibody, but not by prior engraftment of the transgenic strains with WT bone marrow, confirming that the changes observed were a specific transgenic expression of anticoagulants by EC. These results demonstrate that the inflammation in ALI is TF and thrombin dependent, and that expression of anticoagulants by EC significantly inhibits the development of ALI via repression of leukocyte infiltration, most likely via inhibition of chemokine gradients. These data enhance our understanding of the pathology of ALI and suggest a novel therapeutic strategy for treatment.

Aerosolized antibiotics for ventilator-associated pneumonia: a pairwise and Bayesian network meta-analysis.

BACKGROUND: Aerosolized antibiotics have been proposed as a novel and promising treatment option for the treatment of ventilator-associated pneumonia (VAP). However, the optimum aerosolized antibiotics for VAP remain uncertain. METHODS: We included studies from two systematic reviews and searched PubMed, EMBASE, and Cochrane databases for other studies. Eligible studies included randomized controlled trials and observational studies. Extracted data were analyzed by pairwise and network meta-analysis. RESULTS: Eight observational and eight randomized studies were identified for this analysis. By pairwise meta-analysis using intravenous antibiotics as the reference, patients treated with aerosolized antibiotics were associated with significantly higher rates of clinical recovery (risk ratio (RR) 1.21, 95% confidence interval (CI) 1.09-1.34; P = 0.001) and microbiological eradication (RR 1.42, 95% CI 1.22-1.650; P < 0.0001). There were no significant differences in the risks of mortality (RR 0.88, 95% CI 0.74-1.04; P = 0.127) or nephrotoxicity (RR 1.00, 95% CI 0.72-1.39; P = 0.995). Using network meta-analysis, clinical recovery benefits were seen only with aerosolized tobramycin and colistin (especially tobramycin), and microbiological eradication benefits were seen only with colistin. Aerosolized tobramycin was also associated with significantly lower mortality when compared with aerosolized amikacin and colistin and intravenous antibiotics. The assessment of rank probabilities indicated aerosolized tobramycin presented the greatest likelihood of having benefits for clinical recovery and mortality, and aerosolized colistin presented the best benefits for microbiological eradication. CONCLUSIONS: Aerosolized antibiotics appear to be a useful treatment for VAP with respect to clinical recovery and microbiological eradication, and do not increase mortality or nephrotoxicity risks. Our network meta-analysis in patients with VAP suggests that clinical recovery benefits are associated with aerosolized tobramycin and colistin (especially tobramycin), microbiological eradication with aerosolized colistin, and survival with aerosolized tobramycin, mostly based on observational studies. Due to the low levels of evidence, definitive recommendations cannot be made before additional, large randomized studies are carried out.

Efficacy and safety of anti-interleukin-5 therapy in patients with asthma: A pairwise and Bayesian network meta-analysis.

INTRODUCTION: Anti-interleukin-5 therapy has been proposed as a novel and promising treatment option in asthma treatment. However, the optimum monoclonal antibodies for asthma treatment remain uncertain. METHODS: We searched the PubMed, EMBASE and Cochrane databases from their inceptions to June 2018 for randomized controlled trials that reported pulmonary function, adverse events, Asthma Quality of Life Questionnaire (AQLQ) scores, and asthmatic exacerbations resulting from anti-interleukin-5 therapy in asthma patients. Extracted data were analyzed by pairwise and network meta-analysis. RESULTS: Twenty-one randomized studies were identified for this analysis. By pairwise meta-analysis using a placebo as the reference, patients treated with monoclonal antibodies were associated with significantly improved forced expiratory volume (FEV1) values (standard mean difference [SMD], 0.18; 95% confidence interval [CI], 0.12-0.23; P < 0.001), lower rates of adverse events (risk ratio [RR], 0.93; 95% CI, 0.90-0.97; P < 0.001) and significant improvements in the AQLQ scores (SMD, 0.20; 95% CI, 0.13-0.26; P < 0.001). There were no significant differences in exacerbations risks (RR, 0.68; 95% CI, 0.11-4.14; P = 0.097). According to network meta-analysis, adverse events-related benefits were seen only with reslizumab, while AQLQ scores benefits, and pulmonary function benefits were still seen with all three monoclonal antibodies. The assessment of rank probabilities indicated that reslizumab presented the greatest likelihood of having benefits for pulmonary function, reducing adverse events and improving AQLQ scores when compared with the placebo, and mepolizumab presented the best benefits for reducing asthmatic exacerbations. CONCLUSIONS: Anti-interleukin-5 therapy appears to be a safe and effective treatment for asthma patients with respect to pulmonary lung function, adverse events and AQLQ scores, and do not increase asthmatic exacerbations. Our network meta-analysis in patients with asthma suggests that reducing adverse events benefits due to reslizumab, and pulmonary lung function benefits as well as good AQLQ scores are seen with respect to the three antibodies. Network meta-analysis indicates the probability that the best anti-interlukin-5 therapy for asthma patients might be reslizumab, but further trials are required to determine the most effective asthma treatment drug.

The synergistic effect of esophageal squamous cell carcinoma KYSE150 cells and M2 macrophages on lymphatic endothelial cells.

Objective: This study aimed to investigate whether tumor-associated macrophages (TAMs) and esophageal squamous cell carcinoma (ESCC) cells could synergistically influence the generation of lymphatic vessels via the VEGF-C/VEGFR-3 signaling pathway and to address its mechanism. Methods: M2 macrophages were sorted with immunomagnetic beads and induced in vitro. VEGF-C siRNA plasmids were constructed and transfected into M2 macrophages and the ESCC cell line KYSE150. Different conditioned culture media before and after transfection were collected and classified into different groups for culturing ESCC-associated lymphatic endothelial cells (ESCC-LECs). Using the CCK-8 assay, Transwell cell migration assay and Matrigel three-dimensional culture, the proliferation, migration and ring forming abilities of ESCC-LECs before and after transfection were compared, respectively. With ELISA, western blot and q(RT)-PCR, VEGF-C concentrations in conditioned culture media and the protein and mRNA expression levels of VEGFR-3 in LECs before and after transfection were compared, respectively. Results: Before transfection, ESCC-LECs in the group with mixed culture medium had stronger proliferation, migration and ring forming abilities than the other groups. The VEGF-C concentration and VEGFR-3 protein and mRNA expression levels were higher in the mixed culture medium group than in the other groups. After transfection, all indices were the lowest in the mixed culture medium group. Conclusions: M2 macrophages can enhance the proliferation, migration and ring forming abilities of ESCC-LECs. ESCC cells and M2 macrophages have synergistic effects on the proliferation, migration and ring forming abilities of ESCC-LECs. VEGF-C siRNA can inhibit the proliferation, migration and ring forming abilities of ESCC-LECs by silencing the expression of VEGF-C and its receptor VEGFR-3 in KYSE150 cells and M2 macrophages.

[Clinical Analysis of 7 Children with Mature B-cell Acute Lymphoblastic Leukemia].

OBJECTIVE: To evaluate the efficacy of CCCG-BNHL-2015 protocol in treatment of children with mature B-cell acute lymphoblastic leukemia (mature B-ALL). METHODS: Seven pediatric patients with newly diagnosed mature B-ALL were treated by CCCG-BNHL-2015 protocol (risk group R4) in Children's Hospital of Nanjing Medical University from November 2014 to January 2017. RESULTS: The median age of patients at initial diagnosis was 7.2 years (range 4.1 to 11.75 years) with a male predominance (5:2), the clinical characters were as follows: 4 cases combined with thoracic and/or abdominal lumps, only lymphonode was involved in 1 case, bone destruction was complicated in 2 cases and 1 case was complicated with central nervous system leukemia. In 2 children, tumor lysis syndrome appeared at early phase. The lactate dehydrogenase level at diagnosis of all patients extremely increased. All patients achieved complete remission after 2 to 4 courses of therapy. Two among them underwent autologous hematopoietic stem cell transplantation. One with primary central nervous system leukemia relapsed before the last course, then the treatment was abandoned. The rest of 6 patients survived with a median follow-up period of 14 months (ranged from 7 to 28 months), and suffered from different degrees of myelosuppression and infection. No one died from serious complications. CONCLUSION: The CCCG-BNHL-2015 protocol (risk group R4) shows better curative effect, higher safety and remission rate in childhood mature B-cell lymphoblastic leukemia.

[Diurnal Variations of Concentration of Porewater Dissolved CH4 and CO2 in a Brackish Marsh Dominated by Cyperus malaccensis and Phragmites australis During Neap and Spring Tidal Days in the Minjiang River Estuary].

Understanding of diurnal variation of soil porewater dissolved CO2 and CH4 concentration plays an important role in revealing carbon cycling in estuarine wetlands.During neap and spring tidal days in April and September 2010,the diurnal variations of soil porewater dissolved CO2 and CH4 concentrations and main impacting factors in a brackish marsh ecosystem dominated by two species of Cyperus malaccensis(brevifolius) and Phragmites australis(common reed) were determined in the ShanYutan in the Min River estuary,southeast China.The results showed that:① the soil porewater dissolved CH4 concentration during the spring and neap tidal days in April and September ranged from 88.20 to 190.74,53.42 to 141.24,16.27 to 81.89 and 44.90 to 88.53 µmol·L-1,respectively.The mean of dissolved CH4 concentration was higher at nighttime than at daytime during the spring and neap tidal days in April,but the mean of dissolved CH4 concentration was higher at daytime than at nighttime during the spring and neap tidal tidal days in September.② the soil porewater dissolved CO2 concentration during the spring and neap tidal days in September ranged from 19.33 to 40.1 µmol·L-1 and 9.69 to 29.96 µmol·L-1,respectively,and the dissolved CO2 concentration during daytime was lower than that at night;③ the mean of dissolved CO2 concentration was lower during the inundation period than in the exposed soil surface period,but the mean of dissolved CH4 concentration was higher during the inundation period than in the exposed soil surface period.

[Characterization of free and bound organochlorine pesticides in four soil/sediments of the Pearl River Delta, China].

Free and bound residues are the main form of organochlorine pesticides (OCPs) in soils/sediments. Four surface soil/sediments from the Pearl River Delta, China, were selected to characterize free and bound OCPs in different fractions of organic matters in the samples through alka-extraction, HCl/HF demineralization and organic solvent extraction. Total OCPs concentrations of samples were 20.96-134.22 microg x kg(-1), total HCHs concentrations were 5.66-22.87 microg x kg(-1), and total DDTs concentrations were 1.51-11.70 microg x kg(-1). beta-HCH, heptachlor, aldrin, endrin, endosulfan sulfate and methoxychlor were the dominate compounds which took 53.56%-77.26% of total OCPs. Concentrations of free OCPs were 8.46-88.45 microg x kg(-1) and took 40.37%-65.90% of total OCPs while concentrations of bound OCPs were 11.46-45.77 microg x kg(-1) and took 34.10%-59.63% of total OCPs. Most of bound OCPs were in the humic acid and humin fractions of the samples which shows the significantly occurrence of bound OCPs in environment. Distributions of free DDTs and HCHs showed that there were no fresh HCHs poured into these samples but there were fresh DDTs poured into some of the samples. The distribution of OCPs in these two fractions were associated with the organic C content of the fractions, and 94.78%-97.48% of bound OCPs were in humin fraction which took 57.71%-80.55% of total organic C in the samples. Environmental risk estimate showed that some free OCPs such as gamma-HCH, aldrin, endrin and DDTs may have risk to environment and total of free and bound concentration of each compound were 1-30 times higher than free concentration of each compound. Therefore bound OCPs should be considered while making the environmental risk estimate and establishing environmental criteria.

[Expression of HSP70 mRNA and MDR1 mRNA in K562 cells induced by heat shock and ADM].

This study was purpose to investigate the expression levels of HSP70 and MDR1 genes under heat shock and/or adriamycin (ADM) chemotherapy stimulation. The K562 cells were bathed in water at 43 degrees C for 1 hour, then the heat-treated K562 cells were collected and were cultured at 37 degrees C. The expression of HSP70 was assayed by immunocytochemistry, the growth suppression rate of K562 cells was detected by MTT assay, the function of P-gp and the expressions of HSP70 mRNA, MDR1 mRNA were detected by flow cytometry and real-time quantitative PCR (RT-PCR) respectively. The results showed that (1) the synthesis of HSP70 protein in K562 cells treated with high shock (43 degrees C) reached to high level after culture at 37 degrees C for 2 hours, and moved from cytoplasm to nucleolus, the expression of HSP70 began to decrease following 3 hours of culture at 37 degrees C, and gradually reached to normal level after culture at 37 degrees C for 5 hours, the location of HSP70 expression returned to cytoplasm; (2) the expressions of HSP70 mRNA and MDR1 mRNA increased following 43 degrees C heat shock, and were 4 and 5.8 times higher than that of control group at 37 degrees C culture for 2 hours respectively; (3) the expression of P-gp was higher in ADM group than that in control. The expressions of HSP mRNA and MDR1 mRNA increased significantly in heat shock plus ADM group and ADM group as compared with control (p<0.01). It is concluded that the heat shock and ADM chemotherapy both induce over expression of HSP70 and MDR1 which can maintain stability of K562 cells and may be related to formation of the MDR in leukemia.