[Objective] The aim of the research was to study the effect of the ice bath time after heat shock and the incubation time on the transformation efficacy,and to establish a simple and quick transformation method.[Metho...[Objective] The aim of the research was to study the effect of the ice bath time after heat shock and the incubation time on the transformation efficacy,and to establish a simple and quick transformation method.[Method]Competent cells were prepared with two buffer solutions;with the ice bath time after heat shock and the recovery time as the variables,the relationship between these two factors and transformation efficacy was studied.[Result]The transformation efficacy was the best when the ice bath time was 2 min and the recovery time was 30 or 40 min;when the ice bath time and the recovery time was 0 min,a certain amount of transformants still could be obtained.[Conclusion]The ice bath time after heat shock and the recovery time had certain impact on transformation efficacy,but they were not the decisive factors.Therefore,in the general transformation experiment,these two steps could be omitted.展开更多
AIM： To investigate the effect of paeonol on controlling the proliferation of colorectal cancer cell line HT-29 and to discuss its possible mechanism. METHODS： The inhibitory effect of paeonol on proliferation of HT...AIM： To investigate the effect of paeonol on controlling the proliferation of colorectal cancer cell line HT-29 and to discuss its possible mechanism. METHODS： The inhibitory effect of paeonol on proliferation of HT-29 cells was detected by M-I-I- assay. The results of apoptosis were measured by flow cytometry. Immunocytochemical staining was performed to detect the expression of cyclooxygenase-2 （COX-2） and protein p27 in HT-29 cells treated with paeonol at different concentrations. Reverse transcription-polymerase chain reaction （RT- PCR） was used for mRNA analysis. RESULTS： From the data of both MTT and flow cytometry, we observed that cell proliferation was inhibited by different concentrations of paeonol. By immunocytochemical staining, we found that HT-29 cells treated with paeonol （0.024-1.504 mmol/L） reflected reduced expression of COX-2 and increased expression of p27 in a dose-dependent manner. RT-PCR showed that paeonol down-regulated COX-2 and up-regulated p27 in a dose- and time-dependent manner in HT-29 cells. CONCLUSION： One of the apoptotic mechanisms of paeonol is down-regulation of COX-2. p27 is upregulated simultaneously and plays an important part in controlling cell proliferation and is a crucial factor in the Fas/FasL apoptosis pathway.展开更多
The aging of the population is, currently, a major phenomenon, drawing the attention of a number of investigators. The significant increase of life expectancies over the past few decades, in addition to social and eco...The aging of the population is, currently, a major phenomenon, drawing the attention of a number of investigators. The significant increase of life expectancies over the past few decades, in addition to social and economic consequences, has lead to a major change in the morbidity and mortality profile of elders. Heart failure （HF） is a condition in which the heart can not pump enough blood to meet the body＇s needs. HF is predominantly a disorder of the elderly with rates increasing exponentially. The prevalence of HF approximately doubles with each decade of life. As people live longer, the occurrence of HF rises, as well as other conditions that complicate its treatment. Impaired heart function implies a reduced duration of survival. Fortunately, many factors that can prevent HF and improve outcome are known and can be applied at any stage. This review emphasizes the importance of factors inherent in aging itself, focusing on heart disease, particularly as a disease of aging, can help critically refine management of this acute and chronic disease, as well as foster preventive strategies to reduce the incidence of this common malady.展开更多
Nipah （Nypafruticans） is a species of palm trees that grows in mangroves environment near the sea shore. Nipah is potential to produce biofuel energy. The purposes of this research were 1） to determine the optimum ...Nipah （Nypafruticans） is a species of palm trees that grows in mangroves environment near the sea shore. Nipah is potential to produce biofuel energy. The purposes of this research were 1） to determine the optimum bacterial concentration for fermentation to produce high concentration of bio-ethanol, and 2） to determine the optimum incubation time for fermentation to produce high concentration of bio-ethanol. The research had been conducted from June until November 2009 using nipah sap as the substrate and Saceharomyces cerevisiae as a fermentation starter. The experimental design used was a randomized block design （RBD）. Factors tested were starter concentration （5%, 7.5%, 10%） and incubation time （2, 4, 6 days）. The variables observed were concentration of reducing sugar, total microorganism （CFU/mL）, and bio-ethanol production. The results showed that the highest yield of bio-ethanol （8.98%） was produced with 7.5% of starter concentration and 6 days of incubation time.展开更多
The effectiveness of chlorine and ultraviolet light at inactivating indigenous microbes in primary treated wastewater was examined in this study. The inactivation rates for somatic colipahge and F-specific bacteriopha...The effectiveness of chlorine and ultraviolet light at inactivating indigenous microbes in primary treated wastewater was examined in this study. The inactivation rates for somatic colipahge and F-specific bacteriophage were less than 2.5 log and 1 log, respectively, at either free chlorine doses of 6, 15 mg/L and 30 mg/L after 30 minutes contact time. However, E. coli and total coliforms were susceptible to chlorination and inactivated more than 4 log within first 15 minutes of contact time at any chlorine dosage tested. In contrast, the inactivation of bacteriophage was increased when increasing UV fluence. At the same disinfection effectiveness against E. coli, UV disinfection was more effective than chlorination against F-specific bacteriophages.展开更多
Estrogen deficiency has been proposed as a risk factor for alveolar bone loss, but whether or not estrogen will influcence the bone rebuilting process during orthodontic tooth movement and what the mechanisms involved...Estrogen deficiency has been proposed as a risk factor for alveolar bone loss, but whether or not estrogen will influcence the bone rebuilting process during orthodontic tooth movement and what the mechanisms involved remain unclear. The paper aims to provide new information that may elucidate the modulatory effect of estrogen on the bone-resorbing cytokines RANKL and its anti-resorptive factor OPG secrected by HPLFs which are already force-stimulated. The expression of OPG mRNA is rising after mechanical loading either with or without stimulated by estrogen before. But HPDL cells exposured to estrogen for 24 h before loaded tend to express more OPG mRNA. Compared with the no-estrogen group, the inhibit trend of RANKL mRNA is much more apparent in with-estrogen group. Moreover, estrogen and mechanic force time-dependently increased OPG expression and attenuated the RANKL expression.展开更多
It is important to understand the effects of temporal changes in microbial communities in the acidic soils of tea orchards with different fertilizers. A field experiment involving organic fertilizer （OF）, chemical f...It is important to understand the effects of temporal changes in microbial communities in the acidic soils of tea orchards with different fertilizers. A field experiment involving organic fertilizer （OF）, chemical fertilizer （CF）, and unfertilized control （CK） treatments was arranged to analyze the temporal changes in the bacterial and archaeal communities at bimonthly intervals based on the 16S ribosomal RNA （rRNA） gene using terminal restriction fragment length polymorphism （T-RFLP） profiling. The abundances of total bacteria, total archaea, and selected functional genes （bacterial and archaeal amoA, bacterial narG, nirK, nirS, and nosZ） were determined by quantitative poly- merase chain reaction （qPCR）. The results indicate that the structures of bacterial and archaeal communities varied significantly with time and fertilization based on changes in the relative abundance of dominant T-RFs. The abundancy of the detected genes changed with time. The total bacteria, total archaea, and archaeal amoA were less abundant in July. The bacterial amoA and denitrifying genes were less abundant in September, except the nirK gene. The OF treatment increased the abundance of the observed genes, while the CF treatment had little influence on them. The soil temperature significantly affected the bacterial and archaeal community structures. The soil moisture was signif- icantly correlated with the abundance of denitrifying genes. Of the soil chemical properties, soil organic carbon was the most important factor and was significantly correlated with the abundance of the detected genes, except the nirK gene. Overall, this study demonstrated the effects of both temporal alteration and organic fertilizer on the structures of mi- crobial communities and the abundance of genes involved in the nitrogen cycle.展开更多
基金Supported by Foundation for Returned Scholars of Hebei Province(2010)Research Fund for the Doctoral Program of Hebei Normal University(L2009B13)~~
文摘[Objective] The aim of the research was to study the effect of the ice bath time after heat shock and the incubation time on the transformation efficacy,and to establish a simple and quick transformation method.[Method]Competent cells were prepared with two buffer solutions;with the ice bath time after heat shock and the recovery time as the variables,the relationship between these two factors and transformation efficacy was studied.[Result]The transformation efficacy was the best when the ice bath time was 2 min and the recovery time was 30 or 40 min;when the ice bath time and the recovery time was 0 min,a certain amount of transformants still could be obtained.[Conclusion]The ice bath time after heat shock and the recovery time had certain impact on transformation efficacy,but they were not the decisive factors.Therefore,in the general transformation experiment,these two steps could be omitted.
文摘AIM： To investigate the effect of paeonol on controlling the proliferation of colorectal cancer cell line HT-29 and to discuss its possible mechanism. METHODS： The inhibitory effect of paeonol on proliferation of HT-29 cells was detected by M-I-I- assay. The results of apoptosis were measured by flow cytometry. Immunocytochemical staining was performed to detect the expression of cyclooxygenase-2 （COX-2） and protein p27 in HT-29 cells treated with paeonol at different concentrations. Reverse transcription-polymerase chain reaction （RT- PCR） was used for mRNA analysis. RESULTS： From the data of both MTT and flow cytometry, we observed that cell proliferation was inhibited by different concentrations of paeonol. By immunocytochemical staining, we found that HT-29 cells treated with paeonol （0.024-1.504 mmol/L） reflected reduced expression of COX-2 and increased expression of p27 in a dose-dependent manner. RT-PCR showed that paeonol down-regulated COX-2 and up-regulated p27 in a dose- and time-dependent manner in HT-29 cells. CONCLUSION： One of the apoptotic mechanisms of paeonol is down-regulation of COX-2. p27 is upregulated simultaneously and plays an important part in controlling cell proliferation and is a crucial factor in the Fas/FasL apoptosis pathway.
文摘The aging of the population is, currently, a major phenomenon, drawing the attention of a number of investigators. The significant increase of life expectancies over the past few decades, in addition to social and economic consequences, has lead to a major change in the morbidity and mortality profile of elders. Heart failure （HF） is a condition in which the heart can not pump enough blood to meet the body＇s needs. HF is predominantly a disorder of the elderly with rates increasing exponentially. The prevalence of HF approximately doubles with each decade of life. As people live longer, the occurrence of HF rises, as well as other conditions that complicate its treatment. Impaired heart function implies a reduced duration of survival. Fortunately, many factors that can prevent HF and improve outcome are known and can be applied at any stage. This review emphasizes the importance of factors inherent in aging itself, focusing on heart disease, particularly as a disease of aging, can help critically refine management of this acute and chronic disease, as well as foster preventive strategies to reduce the incidence of this common malady.
文摘Nipah （Nypafruticans） is a species of palm trees that grows in mangroves environment near the sea shore. Nipah is potential to produce biofuel energy. The purposes of this research were 1） to determine the optimum bacterial concentration for fermentation to produce high concentration of bio-ethanol, and 2） to determine the optimum incubation time for fermentation to produce high concentration of bio-ethanol. The research had been conducted from June until November 2009 using nipah sap as the substrate and Saceharomyces cerevisiae as a fermentation starter. The experimental design used was a randomized block design （RBD）. Factors tested were starter concentration （5%, 7.5%, 10%） and incubation time （2, 4, 6 days）. The variables observed were concentration of reducing sugar, total microorganism （CFU/mL）, and bio-ethanol production. The results showed that the highest yield of bio-ethanol （8.98%） was produced with 7.5% of starter concentration and 6 days of incubation time.
文摘The effectiveness of chlorine and ultraviolet light at inactivating indigenous microbes in primary treated wastewater was examined in this study. The inactivation rates for somatic colipahge and F-specific bacteriophage were less than 2.5 log and 1 log, respectively, at either free chlorine doses of 6, 15 mg/L and 30 mg/L after 30 minutes contact time. However, E. coli and total coliforms were susceptible to chlorination and inactivated more than 4 log within first 15 minutes of contact time at any chlorine dosage tested. In contrast, the inactivation of bacteriophage was increased when increasing UV fluence. At the same disinfection effectiveness against E. coli, UV disinfection was more effective than chlorination against F-specific bacteriophages.
文摘Estrogen deficiency has been proposed as a risk factor for alveolar bone loss, but whether or not estrogen will influcence the bone rebuilting process during orthodontic tooth movement and what the mechanisms involved remain unclear. The paper aims to provide new information that may elucidate the modulatory effect of estrogen on the bone-resorbing cytokines RANKL and its anti-resorptive factor OPG secrected by HPLFs which are already force-stimulated. The expression of OPG mRNA is rising after mechanical loading either with or without stimulated by estrogen before. But HPDL cells exposured to estrogen for 24 h before loaded tend to express more OPG mRNA. Compared with the no-estrogen group, the inhibit trend of RANKL mRNA is much more apparent in with-estrogen group. Moreover, estrogen and mechanic force time-dependently increased OPG expression and attenuated the RANKL expression.
基金supported by the Research Fund for the Doctoral Program of Higher Education of China(No.20130101110127)the Project of Zhejiang Key Scientific and Technological Innovation Team(No.2010R50039),China
文摘It is important to understand the effects of temporal changes in microbial communities in the acidic soils of tea orchards with different fertilizers. A field experiment involving organic fertilizer （OF）, chemical fertilizer （CF）, and unfertilized control （CK） treatments was arranged to analyze the temporal changes in the bacterial and archaeal communities at bimonthly intervals based on the 16S ribosomal RNA （rRNA） gene using terminal restriction fragment length polymorphism （T-RFLP） profiling. The abundances of total bacteria, total archaea, and selected functional genes （bacterial and archaeal amoA, bacterial narG, nirK, nirS, and nosZ） were determined by quantitative poly- merase chain reaction （qPCR）. The results indicate that the structures of bacterial and archaeal communities varied significantly with time and fertilization based on changes in the relative abundance of dominant T-RFs. The abundancy of the detected genes changed with time. The total bacteria, total archaea, and archaeal amoA were less abundant in July. The bacterial amoA and denitrifying genes were less abundant in September, except the nirK gene. The OF treatment increased the abundance of the observed genes, while the CF treatment had little influence on them. The soil temperature significantly affected the bacterial and archaeal community structures. The soil moisture was signif- icantly correlated with the abundance of denitrifying genes. Of the soil chemical properties, soil organic carbon was the most important factor and was significantly correlated with the abundance of the detected genes, except the nirK gene. Overall, this study demonstrated the effects of both temporal alteration and organic fertilizer on the structures of mi- crobial communities and the abundance of genes involved in the nitrogen cycle.
