Objective:To study evolutionary relationship of the 5'untranslated regions(5'UTRs) in low passage dengue3 viruses(DEN3) isolated from hospitalized children with different clinical manifestations in Bangkok dur...Objective:To study evolutionary relationship of the 5'untranslated regions(5'UTRs) in low passage dengue3 viruses(DEN3) isolated from hospitalized children with different clinical manifestations in Bangkok during 24 year-evolution(1977-2000) comparing to the DEN3prototype(H87).Methods:The 5'UTRs of these Thai DEN3 and the H87 prototype were amplified by RT-PCR and sequenced.Their multiple sequence alignments were done by Codon Code Aligner v 4.0.4 software and their RNA secondary structures were predicted by MFOLD software.Replication of five Thai DEN3 candidates comparing to the 1187 prototype were done in human(HepG2) and the mosquito(C6/36) cell lines.Results:Among these Thai DEN3,the completely identical sequences of their first 89 nucleotides,their high-order secondary structure of 5'UTRs and three SNPs including the predominant C90 T,and two minor SNPs including A109 G and A112 G were found.The C90 T of Thai DEN3.Bangkok isolates was shown predominantly before 1977.Five Thai DEN3 candidates with the predominant C90 T were shown to replicate in human(HepG2) and the mosquito(C6/36) cell lines better than the H87 prototype.However,their highly conserved sequences as well as SNPs of the 5'UTR did not appear to correlate with their disease severity in human.Conclusions:Our findings highlighted evolutionary relationship of the completely identical 89 nucleotide sequence,the high-order secondary structure and the predominant C90 T of the 5'UTR of these Thai DEN3 during 24 year-evolution further suggesting to be their genetic markers and magic targets for future research on antiviral therapy as well as vaccine approaches of Thai DEN3.展开更多
The fine-tuned expression dynamics of the effector genes are pivotal for the transition from vegetative growth to host colonization of pathogenic filamentous fungi.However,mechanisms underlying the dynamic regulation ...The fine-tuned expression dynamics of the effector genes are pivotal for the transition from vegetative growth to host colonization of pathogenic filamentous fungi.However,mechanisms underlying the dynamic regulation of these genes remain largely unknown.Here,through comparative transcriptome and chromatin immunoprecipitation sequencing(ChIP-seq)analyses of the methyltransferase PoKmt6 in rice blast fungus Pyricularia oryzae(syn.Magnaporthe oryzae),we found that PoKmt6-mediated H3K27me3 deposition was enriched mainly at fast-evolving regions and contributed to the silencing of a subset of secreted proteins(SP)and transposable element(TE)families during the vegetative growth of P.oryzae.Intriguingly,we observed that a group of SP genes,which were depleted of H3K27me3 modification,could also be silenced via the H3K27me3-mediated repression of the nearby TEs.In conclusion,our results indicate that H3K27me3 modification mediated by PoKmt6 regulates the expression of some SP genes in fast-evolving regions through the suppression of nearby TEs.展开更多
The messenger RNA 3'-untranslated region(3'UTR)plays an important role in regulation of gene expres-sion on the posttranscriptional level. The 3'UTR con-trols gene expression via orchestrated interactionbe...The messenger RNA 3'-untranslated region(3'UTR)plays an important role in regulation of gene expres-sion on the posttranscriptional level. The 3'UTR con-trols gene expression via orchestrated interactionbetween the structural components of mRNAs(cis-ele-ment) and the specific trans-acting factors(RNA bind-ing proteins and non-coding RNAs). The crosstalk ofthese factors is based on the binding sequences and/or direct protein-protein interaction, or just functionalinteraction. Much new evidence that has accumulatedsupports the idea that several RNA binding factors canbind to common mRNA targets: to the non-overlappingbinding sites or to common sites in a competitive fash-ion. Various factors capable of binding to the sameRNA can cooperate or be antagonistic in their actions.The outcome of the collective function of all factorsbound to the same mRNA 3'UTR depends on manycircumstances, such as their expression levels, affinity to the binding sites, and localization in the cell, which can be controlled by various physiological conditions. Moreover, the functional and/or physical interactions of the factors binding to 3'UTR can change the character of their actions. These interactions vary during the cell cycle and in response to changing physiological condi-tions. Abnormal functioning of the factors can lead to disease. In this review we will discuss how alterations of these factors or their interaction can affect cancer development and promote or enhance the malignant phenotype of cancer cells. Understanding these altera-tions and their impact on 3'UTR-directed posttran-scriptional gene regulation will uncover promising new targets for therapeutic intervention and diagnostics. We will also discuss emerging new tools in cancer di-agnostics and therapy based on 3'UTR binding factors and approaches to improve them.展开更多
Objective To screen the proteins associated with four-and-a-half LIM domains 3(FHL3) 3' untranslated region(3'UTR) in glioma cells. Methods Western blot was adopted to detect the regulatory effect of poly(C)-b...Objective To screen the proteins associated with four-and-a-half LIM domains 3(FHL3) 3' untranslated region(3'UTR) in glioma cells. Methods Western blot was adopted to detect the regulatory effect of poly(C)-binding protein 2(PCBP2) on FHL3. Biotin pull-down and sliver staining were employed to screen and verify the candidate binding proteins of FHL3 3'UTR. Then liquid chromatography-tandem mass spectrometry(LC-MS/MS) and molecule annotation system were used to identify and analyze the candidate binding proteins. Immunoprecipitation was conducted to study the interaction between PCBP2 and polypyrimidine tract-binding protein 1(PTBP1), a binding protein identified by LC-MS/MS. Results PCBP2 could bind to FHL3 mRNA 3'UTR-A and inhibited the expression of FHL3 in T98 G glioms cells. 22 candidate binding proteins were identified. Among them, there were 11 RNA binding proteins, including PCBP2. PTBP1 associated with FHL3 mRNA 3'UTR and interacted with PCBP2 protein. Conclusion PCBP2 and PTBP1 can both associate with FHL3 mRNA 3'UTR through forming a protein complex.展开更多
Dear Editor： Increased homocysteine levels due to vitamin B6 or B12 deficiency or genetic defects in folate pathway genes are associated with an increased incidence of non-syndromic cleft lip with or without cleft p...Dear Editor： Increased homocysteine levels due to vitamin B6 or B12 deficiency or genetic defects in folate pathway genes are associated with an increased incidence of non-syndromic cleft lip with or without cleft palate （NSCLP）tlj. Thymidylate synthase （TS） is a folate-dependent enzyme that catalyzes methylation of 2＇-deoxyuridine-5＇-monophosphate （dUMP） to 2＇-deox- ythymidine-5＇-monophosphate （dTMP）, a rate-limiting step in DNA synthesis,展开更多
Objectives: To obtain very end full-length cDNA ofhepatitis C virus (HCV) 5’ untranslated region(5’UTR) and analyze its primary and secondarystructure.Methods: A patient infected genotype 2a HCV wasidentified by rev...Objectives: To obtain very end full-length cDNA ofhepatitis C virus (HCV) 5’ untranslated region(5’UTR) and analyze its primary and secondarystructure.Methods: A patient infected genotype 2a HCV wasidentified by reverse transcription-nested polymerasechain reaction (RT-PCR) and restriction fragmentlength polymorphism (RFLP). Total RNA isolatedfrom the serum was used as template, and the cDNAof the 5’ untranslated region was amplified using rap-id amplification of cDNA ends (RACE). The frag-ments were recombinated by A-T clone strategy, andthe recombinants were confirmed by RFLP andPCR, and sequenced subsequently. Secondary struc-tures were analysed by RNAdraw.Results: Very end full-length cDNA of genotype 2aHCV 5’ UTR was obtained by RACE. In five clonesobtained, three contained full-length 5’UTR cDNA;A21G, G170A, T222C, T247C, C339T substitutionswere found as compared to HC-J6. Homological re-sults of HCV-1, HC-J6, HC-C2, HC-J8 were 93.6%-94.4%, 92.1%-93%, 98.8%-99.7%, 96.2%-96.5%, respectively; however, the substitutions didnot alter secondary structure. Two of 5 clones weredeletions of 53bp and 135bp at the 5’terminal ofHCV 5’UTR, respectively.Conclusions: RACE can be used to obtain the full-length cDNA of 2a genotype HCV 5’UTR. Genes de-leted at the 5’ terminal of HCV circulate in hepatitisC patients.展开更多
The acquisition of digital regional-scale information and ecological environmental data has high requirements for structural texture,spatial res-olution,and multiple parameter categories,which is challenging to achiev...The acquisition of digital regional-scale information and ecological environmental data has high requirements for structural texture,spatial res-olution,and multiple parameter categories,which is challenging to achieve using satellite remote sensing.Considering the convenient,facilitative,and flexible characteristics of UAV(unmanned air vehicle)remote sensing tech-nology,this study selects a campus as a typical research area and uses the Pegasus D2000 equipped with a D-MSPC2000 multi-spectral camera and a CAM3000 aerial camera to acquire oblique images and multi-spectral data.Using professional software,including Context Capture,ENVI,and ArcGIS,a 3D(three-dimensional)campus model,a digital orthophoto map,and multi-spectral remote sensing map drawing are realized,and the geometric accuracy of typical feature selection is evaluated.Based on a quantitative remote sensing model,the campus ecological environment assessment is performed from the perspectives of vegetation and water body.The results presented in this study could be of great significance to the scientific management and sustainable development of regional natural resources.展开更多
[Objective] To explore the polymorphism of the 3′ flank region of equine IGF-Ⅰ gene. [Method] The 3′ flank region sequences of IGF-Ⅰ gene were amplified from genomic DNA of 270 horses, which included 4 types of Mo...[Objective] To explore the polymorphism of the 3′ flank region of equine IGF-Ⅰ gene. [Method] The 3′ flank region sequences of IGF-Ⅰ gene were amplified from genomic DNA of 270 horses, which included 4 types of Mongolian horse, Sanhe horse and Thoroughbred, and then analyzed by PCR-SSCP. [Result] Three genotypes (AA, BB and AB) were detected by PCR-SSCP and the distribution of genotypes of all research objects except Xinihe horse and Baerhu horse were in line with the "Hardy-Weinberg Law". [Conclusion] There was a polymorphic locus in the 3′ flank region of IGF-Ⅰ gene, which might affect the equine growth and development mechanism. The study is of important theoretical and practical significance to improve the performance and to develop equine industry.展开更多
Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is deter...Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others show the characteristic of tectonic boundary, indicating that the faults likely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the SichuanYunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the India and the Asia plates. The crustal velocity in the SichuanYunnan rhombic block generally shows normal value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.展开更多
AIM:To evaluate the in vitro effect of amoxicillin and clarithromycin on the cag pathogenicity island(cag PAI).METHODS:One hundred and forty-nine clinical isolates of Helicobacter pylori(H.pylori)cultured from gastric...AIM:To evaluate the in vitro effect of amoxicillin and clarithromycin on the cag pathogenicity island(cag PAI).METHODS:One hundred and forty-nine clinical isolates of Helicobacter pylori(H.pylori)cultured from gastric biopsies from 206 Colombian patients with dyspeptic symptoms from a high-risk area for gastric cancer were included as study material.Antimicrobial susceptibility was determined by the agar dilution method.Resistant isolates at baseline and in amoxicillin and clarithromycin serial dilutions were subjected to genotyping(cagA,vacA alleles s and m),Glu-Pro-Ile-Tyr-Ala(EPIYA)polymerase chain reaction and random amplified polymorphic DNA(RAPD).Images of the RAPD amplicons were analyzed by Gel-Pro Analyzer 4.5program.Cluster analyses was done using SPSS 15.0statistical package,where each of the fingerprint bands were denoted as variables.Dendrograms were designed by following Ward’s clustering method and the estimation of distances between each pair of H.pylori isolates was calculated with the squared Euclidean distance.RESULTS:Resistance rates were 4%for amoxicillin and 2.7%for clarithromycin with 2%double resistances.Genotyping evidenced a high prevalence of the genotype cagA-positive/vacA s1m1.The 3’region of cagA gene was successfully amplified in 92.3%(12/13)of the baseline resistant isolates and in 60%(36/60)of the resistant isolates growing in antibiotic dilutions.Upon observing the distribution of the number of EPIYA repetitions in each dilution with respect to baseline isolates,it was found that in 61.5%(8/13)of the baseline isolates,a change in the number of EPIYA repetitions lowered antibiotic pressure.The gain and loss of EPIYA motifs resulted in a diversity of H.pylori subclones after bacterial adjustment to changing conditions product of antibiotic pressure.RAPD PCR evidenced the close clonal relationship between baseline isolates and isolates growing in antibiotic dilutions.CONCLUSION:Antibiotic pressure does not induce loss of the cag pathogenicity island,but it can leadin most cases-to genetic rearrangements within the3’region cagA of the founding bacteria that can affect the level of tyrosine phosphorylation impacting on its cellular effects and lead to divergence of cagA-positive subclones.展开更多
基金supported by two research grants of Associate Professor Dr.W.Attatippaholkun:Grant No.493-5600-G-00-3461,Program in Science and Technology Cooperation,Human Capacity Development,Bureau for Global Programs,Field Support and Research,US Agency for International Development,Washington,DCThe Royal Golden Jubilee-Ph.D Program,Thailand Research Fund,Thailand
文摘Objective:To study evolutionary relationship of the 5'untranslated regions(5'UTRs) in low passage dengue3 viruses(DEN3) isolated from hospitalized children with different clinical manifestations in Bangkok during 24 year-evolution(1977-2000) comparing to the DEN3prototype(H87).Methods:The 5'UTRs of these Thai DEN3 and the H87 prototype were amplified by RT-PCR and sequenced.Their multiple sequence alignments were done by Codon Code Aligner v 4.0.4 software and their RNA secondary structures were predicted by MFOLD software.Replication of five Thai DEN3 candidates comparing to the 1187 prototype were done in human(HepG2) and the mosquito(C6/36) cell lines.Results:Among these Thai DEN3,the completely identical sequences of their first 89 nucleotides,their high-order secondary structure of 5'UTRs and three SNPs including the predominant C90 T,and two minor SNPs including A109 G and A112 G were found.The C90 T of Thai DEN3.Bangkok isolates was shown predominantly before 1977.Five Thai DEN3 candidates with the predominant C90 T were shown to replicate in human(HepG2) and the mosquito(C6/36) cell lines better than the H87 prototype.However,their highly conserved sequences as well as SNPs of the 5'UTR did not appear to correlate with their disease severity in human.Conclusions:Our findings highlighted evolutionary relationship of the completely identical 89 nucleotide sequence,the high-order secondary structure and the predominant C90 T of the 5'UTR of these Thai DEN3 during 24 year-evolution further suggesting to be their genetic markers and magic targets for future research on antiviral therapy as well as vaccine approaches of Thai DEN3.
基金the grants from the National Natural Science Foundation of China(U1805232,31770156,and 32172365)the China Postdoctoral Science Foundation(2021M690637)。
文摘The fine-tuned expression dynamics of the effector genes are pivotal for the transition from vegetative growth to host colonization of pathogenic filamentous fungi.However,mechanisms underlying the dynamic regulation of these genes remain largely unknown.Here,through comparative transcriptome and chromatin immunoprecipitation sequencing(ChIP-seq)analyses of the methyltransferase PoKmt6 in rice blast fungus Pyricularia oryzae(syn.Magnaporthe oryzae),we found that PoKmt6-mediated H3K27me3 deposition was enriched mainly at fast-evolving regions and contributed to the silencing of a subset of secreted proteins(SP)and transposable element(TE)families during the vegetative growth of P.oryzae.Intriguingly,we observed that a group of SP genes,which were depleted of H3K27me3 modification,could also be silenced via the H3K27me3-mediated repression of the nearby TEs.In conclusion,our results indicate that H3K27me3 modification mediated by PoKmt6 regulates the expression of some SP genes in fast-evolving regions through the suppression of nearby TEs.
文摘The messenger RNA 3'-untranslated region(3'UTR)plays an important role in regulation of gene expres-sion on the posttranscriptional level. The 3'UTR con-trols gene expression via orchestrated interactionbetween the structural components of mRNAs(cis-ele-ment) and the specific trans-acting factors(RNA bind-ing proteins and non-coding RNAs). The crosstalk ofthese factors is based on the binding sequences and/or direct protein-protein interaction, or just functionalinteraction. Much new evidence that has accumulatedsupports the idea that several RNA binding factors canbind to common mRNA targets: to the non-overlappingbinding sites or to common sites in a competitive fash-ion. Various factors capable of binding to the sameRNA can cooperate or be antagonistic in their actions.The outcome of the collective function of all factorsbound to the same mRNA 3'UTR depends on manycircumstances, such as their expression levels, affinity to the binding sites, and localization in the cell, which can be controlled by various physiological conditions. Moreover, the functional and/or physical interactions of the factors binding to 3'UTR can change the character of their actions. These interactions vary during the cell cycle and in response to changing physiological condi-tions. Abnormal functioning of the factors can lead to disease. In this review we will discuss how alterations of these factors or their interaction can affect cancer development and promote or enhance the malignant phenotype of cancer cells. Understanding these altera-tions and their impact on 3'UTR-directed posttran-scriptional gene regulation will uncover promising new targets for therapeutic intervention and diagnostics. We will also discuss emerging new tools in cancer di-agnostics and therapy based on 3'UTR binding factors and approaches to improve them.
基金Supported by Peking Union Medical College Youth Fundthe Fundamental Research Funds for the Central Universities(3332013052)
文摘Objective To screen the proteins associated with four-and-a-half LIM domains 3(FHL3) 3' untranslated region(3'UTR) in glioma cells. Methods Western blot was adopted to detect the regulatory effect of poly(C)-binding protein 2(PCBP2) on FHL3. Biotin pull-down and sliver staining were employed to screen and verify the candidate binding proteins of FHL3 3'UTR. Then liquid chromatography-tandem mass spectrometry(LC-MS/MS) and molecule annotation system were used to identify and analyze the candidate binding proteins. Immunoprecipitation was conducted to study the interaction between PCBP2 and polypyrimidine tract-binding protein 1(PTBP1), a binding protein identified by LC-MS/MS. Results PCBP2 could bind to FHL3 mRNA 3'UTR-A and inhibited the expression of FHL3 in T98 G glioms cells. 22 candidate binding proteins were identified. Among them, there were 11 RNA binding proteins, including PCBP2. PTBP1 associated with FHL3 mRNA 3'UTR and interacted with PCBP2 protein. Conclusion PCBP2 and PTBP1 can both associate with FHL3 mRNA 3'UTR through forming a protein complex.
基金funding from the Indian Council of Medical Research(ICMR),Government of India(Project Ref.No.56/15/2007-BMS)
文摘Dear Editor： Increased homocysteine levels due to vitamin B6 or B12 deficiency or genetic defects in folate pathway genes are associated with an increased incidence of non-syndromic cleft lip with or without cleft palate （NSCLP）tlj. Thymidylate synthase （TS） is a folate-dependent enzyme that catalyzes methylation of 2＇-deoxyuridine-5＇-monophosphate （dUMP） to 2＇-deox- ythymidine-5＇-monophosphate （dTMP）, a rate-limiting step in DNA synthesis,
基金This work was supported by two grants from National Science Foundation of China (No: 39770684, 30170844).
文摘Objectives: To obtain very end full-length cDNA ofhepatitis C virus (HCV) 5’ untranslated region(5’UTR) and analyze its primary and secondarystructure.Methods: A patient infected genotype 2a HCV wasidentified by reverse transcription-nested polymerasechain reaction (RT-PCR) and restriction fragmentlength polymorphism (RFLP). Total RNA isolatedfrom the serum was used as template, and the cDNAof the 5’ untranslated region was amplified using rap-id amplification of cDNA ends (RACE). The frag-ments were recombinated by A-T clone strategy, andthe recombinants were confirmed by RFLP andPCR, and sequenced subsequently. Secondary struc-tures were analysed by RNAdraw.Results: Very end full-length cDNA of genotype 2aHCV 5’ UTR was obtained by RACE. In five clonesobtained, three contained full-length 5’UTR cDNA;A21G, G170A, T222C, T247C, C339T substitutionswere found as compared to HC-J6. Homological re-sults of HCV-1, HC-J6, HC-C2, HC-J8 were 93.6%-94.4%, 92.1%-93%, 98.8%-99.7%, 96.2%-96.5%, respectively; however, the substitutions didnot alter secondary structure. Two of 5 clones weredeletions of 53bp and 135bp at the 5’terminal ofHCV 5’UTR, respectively.Conclusions: RACE can be used to obtain the full-length cDNA of 2a genotype HCV 5’UTR. Genes de-leted at the 5’ terminal of HCV circulate in hepatitisC patients.
基金supported by the National Natural Science Foundation of China (Grant No.42171311)the Open Fund of State Key Laboratory of Remote Sensing Science (Grant No.OFSLRSS202218)+1 种基金the Key Research and Development Program of the Hainan Province,China (Grant No.ZDYF2021SHFZ105)the Training Program of Excellent Master Thesis of Zhejiang Ocean University.
文摘The acquisition of digital regional-scale information and ecological environmental data has high requirements for structural texture,spatial res-olution,and multiple parameter categories,which is challenging to achieve using satellite remote sensing.Considering the convenient,facilitative,and flexible characteristics of UAV(unmanned air vehicle)remote sensing tech-nology,this study selects a campus as a typical research area and uses the Pegasus D2000 equipped with a D-MSPC2000 multi-spectral camera and a CAM3000 aerial camera to acquire oblique images and multi-spectral data.Using professional software,including Context Capture,ENVI,and ArcGIS,a 3D(three-dimensional)campus model,a digital orthophoto map,and multi-spectral remote sensing map drawing are realized,and the geometric accuracy of typical feature selection is evaluated.Based on a quantitative remote sensing model,the campus ecological environment assessment is performed from the perspectives of vegetation and water body.The results presented in this study could be of great significance to the scientific management and sustainable development of regional natural resources.
文摘[Objective] To explore the polymorphism of the 3′ flank region of equine IGF-Ⅰ gene. [Method] The 3′ flank region sequences of IGF-Ⅰ gene were amplified from genomic DNA of 270 horses, which included 4 types of Mongolian horse, Sanhe horse and Thoroughbred, and then analyzed by PCR-SSCP. [Result] Three genotypes (AA, BB and AB) were detected by PCR-SSCP and the distribution of genotypes of all research objects except Xinihe horse and Baerhu horse were in line with the "Hardy-Weinberg Law". [Conclusion] There was a polymorphic locus in the 3′ flank region of IGF-Ⅰ gene, which might affect the equine growth and development mechanism. The study is of important theoretical and practical significance to improve the performance and to develop equine industry.
基金Foundation item: National Scientific and Technological Development Program (95-973-02-02) the Climb Program (95-S-05-01) of National Scientific and Technological Ministry of China and the State Natural Sciences Foundation of China (49874021).
文摘Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others show the characteristic of tectonic boundary, indicating that the faults likely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the SichuanYunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the India and the Asia plates. The crustal velocity in the SichuanYunnan rhombic block generally shows normal value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.
基金Supported by The Administrative Department on Science and Innovation of the Republic of Colombia-COLCIENCIAS,No.RC-1106-408-20549,RC-1106-493-26237its program:Jóvenes Investigadores e Innovadores"Virginia Gutiérrez de Pineda",and by the Universidad del Valle,Cali,Colombia
文摘AIM:To evaluate the in vitro effect of amoxicillin and clarithromycin on the cag pathogenicity island(cag PAI).METHODS:One hundred and forty-nine clinical isolates of Helicobacter pylori(H.pylori)cultured from gastric biopsies from 206 Colombian patients with dyspeptic symptoms from a high-risk area for gastric cancer were included as study material.Antimicrobial susceptibility was determined by the agar dilution method.Resistant isolates at baseline and in amoxicillin and clarithromycin serial dilutions were subjected to genotyping(cagA,vacA alleles s and m),Glu-Pro-Ile-Tyr-Ala(EPIYA)polymerase chain reaction and random amplified polymorphic DNA(RAPD).Images of the RAPD amplicons were analyzed by Gel-Pro Analyzer 4.5program.Cluster analyses was done using SPSS 15.0statistical package,where each of the fingerprint bands were denoted as variables.Dendrograms were designed by following Ward’s clustering method and the estimation of distances between each pair of H.pylori isolates was calculated with the squared Euclidean distance.RESULTS:Resistance rates were 4%for amoxicillin and 2.7%for clarithromycin with 2%double resistances.Genotyping evidenced a high prevalence of the genotype cagA-positive/vacA s1m1.The 3’region of cagA gene was successfully amplified in 92.3%(12/13)of the baseline resistant isolates and in 60%(36/60)of the resistant isolates growing in antibiotic dilutions.Upon observing the distribution of the number of EPIYA repetitions in each dilution with respect to baseline isolates,it was found that in 61.5%(8/13)of the baseline isolates,a change in the number of EPIYA repetitions lowered antibiotic pressure.The gain and loss of EPIYA motifs resulted in a diversity of H.pylori subclones after bacterial adjustment to changing conditions product of antibiotic pressure.RAPD PCR evidenced the close clonal relationship between baseline isolates and isolates growing in antibiotic dilutions.CONCLUSION:Antibiotic pressure does not induce loss of the cag pathogenicity island,but it can leadin most cases-to genetic rearrangements within the3’region cagA of the founding bacteria that can affect the level of tyrosine phosphorylation impacting on its cellular effects and lead to divergence of cagA-positive subclones.
