We previously reported that many ingenol compounds derived from Euphoria kansui exhibit topoisomerase inhibitory activity. 20-O-ingenolEZ in these compounds exerted inhibitory effects on both topoisomerase II (topo II...We previously reported that many ingenol compounds derived from Euphoria kansui exhibit topoisomerase inhibitory activity. 20-O-ingenolEZ in these compounds exerted inhibitory effects on both topoisomerase II (topo II) activity and cell proliferative activity. Topoisomerase II inhibitors can be divided into the poison and catalytic inhibitor types and 20-O-ingenolEZ is a catalytic inhibitor and inhibits topo IIα through inhibition of ATPase activity, but induces topo II-mediated DNA damage and apoptosis in BLM-/- DT40 cells through the induction of the DNA damage checkpoint, similar to the poison type inhibitor adriamycin. The ATPase inhibitor of topo II ICRF-193 also showed poison-like characteristics in the same cell line. However, the inhibitory effects of ICRF-193 on the proliferation of BLM-/- DT40 cells differed from those of 20-O-ingenolEZ, as did the specificity of its inhibition of the proliferation of other cell lines. 20-O-ingenolEZ showed hypersensitive inhibition of the proliferation of MCF-7 cells and BLM-/- DT40 cells with mutated DNA repair-related genes.展开更多
[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea sn...[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea snakes.[Methods]All COI and cytb gene sequences on GenBank were searched and downloaded.After the comparison with Mega software,clustering trees of MrBayes system were established.[Results]Interspecies distances were greater than intraspecies distances for the two genes.The topological structures of their molecular hierarchical clustering trees were clear,and the support rates were high.[Conclusions]Therefore,it is concluded that not the DNA barcode of each species must be gene COI.Cytb is more suitable in terms of the mitochondrial gene of sea snakes.展开更多
AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method b...AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method by using abundant double-stranded cDNA messages provided by two self-constructed cDNA libraries (Allitridi-treated and paternal HGC cell line BGC823 cells cDNA libraries respectively). Bam H I and Xho I restriction sites harbored in the library vector were used to select representations. Northern and Slot blots analyses were employed to identify the obtained difference products. RESULTS: Fragments released from the cDNA library vector after restriction endonuclease digestion acted as good marker indicating the appropriate digestion degree for library DNA. Two novel expressed sequence tags (ESTs) and a recombinant gene were obtained. Slot blots result showed a 8-fold increase of glia-derived nexin/protease nexin 1 (GDN/PN1) gene expression level and 4-fold increase of hepatitis B virus x-interacting protein (XIP) mRNA level in BGC823 cells after Allitridi treatment for 72h. CONCLUSION: Elevated levels of GDN/PN1 and XIP mRNAs induced by Allitridi provide valuable molecular evidence for elucidating the garlic's efficacies against neurodegenerative and inflammatory diseases. Isolation of a recombinant gene and two novel ESTs further show cDNA RDA based on cDNA libraries to be a powerful method with high specificity and reproducibility in cloning differentially expressed genes.展开更多
Persistent infection wit h high-risk types of human papillomavirus(HPV) is known to cause cervical cancer;however,additional genetic and epigenetic alterations are required for progression from precancerous disease to...Persistent infection wit h high-risk types of human papillomavirus(HPV) is known to cause cervical cancer;however,additional genetic and epigenetic alterations are required for progression from precancerous disease to invasive cancer.DNA methylation is an early and frequent molecular alteration in cervical carcinogenesis.In this review,we summarize DNA methylation within the HPV genome and human genome and identify its clinical implications.Methylation of the HPV long control region(LCR) and L1 gene is common during cervical carcinogenesis and increases with the severity of the cervical neoplasm.The L1 gene of HPV16 and HPV18 is consistently hypermethylated in invasive cervical cancers and can potentially be used as a clinical marker of cancer progression.Moreover,promoters of tumor suppressor genes(TSGs) involved in many cellular pathways are methylated in cervical precursors and invasive cancers.Some are associated with squamous cell carcinomas,and others are associated with adenocarcinomas.Identification of methylated TSGs in Pap smear could be an adjuvant test in cervical cancer screening for triage of women with high-risk HPV,atypical squamous cells of undetermined significance,or low grade squamous intraepithelial lesion(LSIL).However,consistent panels must be validated for this approach to be translated to the clinic.Furthermore,reversion of methylated TSGs using demethylating drugs may be an alternative anticancer treatment,but demethylating drugs without toxic carcinogenic and mutagenic properties must be identified and validated.展开更多
DNA methylation plays an important role in plant growth and development,and in regulating the activity of transposable elements(TEs).Research on DNA methylation-related(DMR)genes has been reported in Arabidopsis,but l...DNA methylation plays an important role in plant growth and development,and in regulating the activity of transposable elements(TEs).Research on DNA methylation-related(DMR)genes has been reported in Arabidopsis,but little research on DMR genes has been reported in Brassica rapa and Brassica oleracea,the genomes of which exhibit significant differences in TE content.In this study,we identified 78 and 77 DMR genes in Brassica rapa and Brassica oleracea,respectively.Detailed analysis revealed that the numbers of DMR genes in different DMR pathways varied in B.rapa and B.oleracea.The evolutionary selection pressure of DMR genes in B.rapa and B.oleracea was compared,and the DMR genes showed differential evolution between these two species.The nucleotide diversity(π)and selective sweep(Tajima’s D)revealed footprints of selection in the B.rapa and B.oleracea populations.Transcriptome analysis showed that most DMR genes exhibited similar expression characteristics in B.rapa and B.oleracea.This study dissects the evolutionary differences and genetic variations of the DMR genes in B.rapa and B.oleracea,and will provide valuable resources for future research on the divergent evolution of DNA methylation between B.rapa and B.oleracea.展开更多
Bicoid is one of the important Drosophila maternal genes involved in the control of embryo polarity and larvae segmentation. To clone and characterize the rice bicoid-related genes, one cDNA clone, Rb24 (EMBL accessio...Bicoid is one of the important Drosophila maternal genes involved in the control of embryo polarity and larvae segmentation. To clone and characterize the rice bicoid-related genes, one cDNA clone, Rb24 (EMBL accession number: AJ2771380), was isolated by screening of rice unmature seed cDNA library. Sequence analysis indicates that Rb24 contains a putative amino acid sequence, which is homologous to unique 8 amino acids sequence within Drosophila bicoid homeodomain (50% identity, 75% similarity) and involves a lys-9 in putative helix 3. Northern blot analysis of rice RNA has shown that this sequence is expressed in a tissue-specific manner. The transcript was detected strongly in young panicles, but less in young leaves and roots. This results are further confirmed with paraffin section in situ hybridization. The signal is intensive in rice globular embryo and located at the apical tip of the embryo, then, along with the development of embryo, the signal is getting reduced and transfers into both sides of embryo. The existence of bicoid-related sequence in rice embryo and the similarity of polar distribution of bicoid and Rb24 mRNA in early embryo development may implicates a conserved maternal regulation mechanism of body axis presents in Drosophila and in rice.展开更多
Objective： The aim of the study was to observe the expressions of genes related to genome stability and DNA repair in the members of nasopharyngeal carcinoma （NPC） clustedng families. Methods： In the Zhongshan Cit...Objective： The aim of the study was to observe the expressions of genes related to genome stability and DNA repair in the members of nasopharyngeal carcinoma （NPC） clustedng families. Methods： In the Zhongshan City where there is highly incidence rate of NPC, we chose the members of the NPC clustering families as objects, and the patients of nasopharyngitis and NPC as the control group. We isolated the RNA from the nasopharyngeal tissue, and synthesized its cRNA, the genome stability and DNA repair genes chip technique, chemiluminescent detection and real-time fluorescence quantita- tive technique were used to examine the genome stability and DNA repair genes in the nasopharyngeal tissue. Results： More genome stability and DNA repair genes were up-regulated in the members of the NPC clustering families than the NPC patients, and the range of up-regulated was high, with the over up-regulated 100 times genes including TEP1, MSH4, PMS2LI. Fewer genome stability and DNA repair genes were down-regulated in the members of the NPC clustering families than the NPC patients, the ubiquitin genes almost were down-regulated, the results also could be confirmed by real-time fluorescence quantitative PCR. Conclusion： There are specially expression character of genome stability and DNA repair genes in the members of NPC clustering families.展开更多
Bacillus thuringiensis (Bt) strain C002 contains crylAa, cry2Ab, crylCa insecticidal crystal genes and an unkown gene cryX, among which crylCa is located in a 6 -9 kb EcoR I fragment of the chromosomal DNA. The total ...Bacillus thuringiensis (Bt) strain C002 contains crylAa, cry2Ab, crylCa insecticidal crystal genes and an unkown gene cryX, among which crylCa is located in a 6 -9 kb EcoR I fragment of the chromosomal DNA. The total DNA and the plasmids DNA libraries of C002 were constructed in Bt-E. coli shuttle plasmid pHT315 by inserting 6 - 9 kb chromosomal and plasmid DNA fragments prepared respectively with EcoR I complete and 5au3A I partial digestion. On the basis of every 50 transformants pooled together from 5-10 tubes, the pools containing about 2 000 transformants from the plasmids DNA library and 400 transformants from the total DNA library were rapidly screened by PCR-RFLP. Clones containing crylAa, cryX, crylCa , and cry2Ab were isolated and named as pHT-1Aa, pHT-X, pHT-1Ca and pHT-2Ab respectively. Restriction analysis indicated that pHT-1Aa, pHT-1Ca and pHT-2Ab had the typical physical map of the homologous cry genes. Furthermore, each plasmid was transferred into Bt acrystalliferous strain cryB- by eletropora-tion. SDS-PAGE result showed that transformant of pHT-1Ca expressed 130 kDa protein and bioassay result proved its high toxicity against Spodotera exigua 1st instar larvae with 100% corrected motality.展开更多
Microsatellite instability (MSI) is used as a molecular marker for defective DNA mismatch repair (MMR) genes.We report here alterations of MSI in 15 malignant astrocytomas (WHO grade Ⅲ) and glioblastomas (GBM; WHO gr...Microsatellite instability (MSI) is used as a molecular marker for defective DNA mismatch repair (MMR) genes.We report here alterations of MSI in 15 malignant astrocytomas (WHO grade Ⅲ) and glioblastomas (GBM; WHO grade Ⅳ) of pediatric patients (2-21 years) and 12 GBM from adults (44-68 years) by comparative analysis of BAT25/BAT26 loci and 10 other microsatellite markers. High-level microsatellite instability (MSI-H) occurred in 4 of the 15 pediatric cases (26.7%) and in 1 of the 12 adult GBM cases (8.3%). Low-level mi-展开更多
The chloroplast is one of the most important organs in plants because of its essential role in photosynthesis.Studies have shown that the chloroplast was once a free-living cyanobacteria and was integrated into the ho...The chloroplast is one of the most important organs in plants because of its essential role in photosynthesis.Studies have shown that the chloroplast was once a free-living cyanobacteria and was integrated into the host species through endosymbiosis（Goksoyr.1967）.after which a large number of its genes had been donated to the host nuclear genome（Heins and Soll, 1998）.展开更多
When the loop-mediated isothermal amplification(LAMP)assay is used for detecting target genes,DNA extraction is unnecessary in many cases.Simple pretreatment(e.g.heating)is enough to obtain rather sensitive responses....When the loop-mediated isothermal amplification(LAMP)assay is used for detecting target genes,DNA extraction is unnecessary in many cases.Simple pretreatment(e.g.heating)is enough to obtain rather sensitive responses.Even test samples without any pretreatment can be used as template.This feature suggests that LAMP is superior to PCR in developing point-of-care test strategies.In this study,using Stx1 gene from E.coli as model,we verified that viable cells,dead cells and extracellular DNA could function as template in the LAMP assay.In the incubation at 63℃,viable bacteria in the LAMP reaction mixture lysed completely within 2 min,providing DNA template for nucleic acid amplification.The Stx1 gene in diluted culture medium,spiked tap water,spiked seawater and real seawater all could be detected,with or without the step of DNA extraction.We found that the complex substances in real sample(e.g.natural seawater)exhibited considerable inhibitory effect on the sensitivity of the LAMP assay.These outcomes are meaningful for building a point-of-care strategy by employing the LAMP assay for environmental monitoring,bio-resource surveys,food safety,etc.in particular those based on environmental DNA.展开更多
Objective: To investigate the effects of DNA methylation and histone deacetylase inhibitors in the re-expression of P16 and RASSIF1A of QBC939. Methods: The QBC939 cells were treated with hydralazine and valproate eit...Objective: To investigate the effects of DNA methylation and histone deacetylase inhibitors in the re-expression of P16 and RASSIF1A of QBC939. Methods: The QBC939 cells were treated with hydralazine and valproate either alone or combined, and the control group was added with RPIM-1640 culture medium. After 48 h, the expression of P16 and RASSF1A genes were evaluated by reverse transcription-PCR, Western blot, and the methylation status of the two genes were detected with MSP (methylation specific PCR). Results: Hydralazine and valproate could induce demethylation of the promoter region of the two genes, and could make them re-active. The expressions of P16 and RASSF1A of cells treated with both drugs were higher than that of the cells treated with either hydralazine or valproate (P < 0.01). There was no RASSF1A gene, and few P16 gene expressing in the control group. The demethylation effect could be found in the groups treated with hydralazine or both drugs, whereas no demethylation effect happened in the valproate group. Conclusion: The two drugs could synergistically re-express P16 and RASSF1A genes silenced in QBC939, and they exerted a great anti-tumour effect on QBC cells.展开更多
Esophageal cancer(EC)was an aggressive malignant neoplasm characterized by high morbidity and poor prognosis.Identifying the changes in DNA damage repair genes helps to better understand the mechanisms of carcinoma pr...Esophageal cancer(EC)was an aggressive malignant neoplasm characterized by high morbidity and poor prognosis.Identifying the changes in DNA damage repair genes helps to better understand the mechanisms of carcinoma progression.In this study,by comparing EC samples and normal samples,we found a total of 132 DDR expression with a significant difference.Moreover,we revealed higher expression of POLN,PALB2,ATM,PER1,TOP3B and lower expression of HMGB1,UBE2B were correlated to longer OS in EC.In addition,a prognostic risk score based on 7 DDR gene expression(POLN,HMGB1,TOP3B,PER1,UBE2B,ATM,PALB2)was constructed for the prognosis of EC.Meanwhile,EC cancer samples were divided into 3 subtypes based on 132 DDR genes expressions.Clinical profile analysis showed cluster C1 and C2 showed a similar frequency of T2,which was remarked higher than that in cluster 3.Moreover,we found the immune cell inflation levels were significantly changed in different subtypes of EC.The infiltration levels of T cell CD8+,B cell and NK cells were greatly higher in cluster 2 than that in cluster 1 and cluster 3.The results showed T cell CD4+infiltration levels were dramatically higher in cluster 1 than that in cluster 2 and cluster 3.Finally,we perform bioinformatics analysis of DEGs among 3 subtypes of EC and found DDR genes may be related to multiple signaling,such as Base excision repair,Cell cycle,Hedgehog signaling pathway,and Glycolysis/Gluconeogenesis.These results showed DDR genes may serve as new target for the prognosis of EC and prediction of the potential response of immune therapy in EC.展开更多
5-methylcytosine (m5C) as a rare base exists in eucaryotic genomes, it is a normal constituent of many eucaryotic DNA, whose existence is a character of eucaryotic DNA. In the regular physiological conditions, cytosin...5-methylcytosine (m5C) as a rare base exists in eucaryotic genomes, it is a normal constituent of many eucaryotic DNA, whose existence is a character of eucaryotic DNA. In the regular physiological conditions, cytosine residue of eucaryotic DNA is methylated to be popular. Up to the present, many people consider that the m5C may be mutation hotspots by the m5C deamination leading to gene mutation. Our theoretical investigations indicated that the spontaneous mutation caused by the transition of G - C-A - T, in eukaryotic DNA, may be a result caused by the tautomer changing base pairs and may also be caused by other factor actions, however it could not be caused by the deamination of m5C.展开更多
Objective: To develop a sensitive, specific and simple method for detection of extremely low numbers of T. pallidum in clinical specimens, as a significant addition to the serologic tests for syphilis diagnosis. Metho...Objective: To develop a sensitive, specific and simple method for detection of extremely low numbers of T. pallidum in clinical specimens, as a significant addition to the serologic tests for syphilis diagnosis. Methods: Double-tube nested PCR(DN-PCR) and single-tube nested PCR(SN-PCR) assays were performed to amplify specific fragments of the DNA poly-merase I gene(polA) of T. pallidum. Sensitivity and specificity of the two PCR assays were tested. Eighty-six whole blood specimens from persons with suspected syphilis were detected by the two nested PCR methods. The TPPA test was used as a comparison for detecting syphilis in sera from corresponding patients. Results: Only specific amplicons could be obtained during amplification of the T. pallidum polA gene and the detection limit was approximately 1 organism when analyzed on gel by the two PCR methods. Of 86 clinical specimens, 62 were positive by TPPA. Of these, 54 and 51 were positive by the DN-PCR and SN-PCR, respectively, which does not represent a statistically significant difference between the two PCR tests. Of 24 TPPA-negative specimens, 5 were positive by both DN-PCR assay and SN-PCR assay. Conclusion: The SN- polA PCR method is extremely sensitive, specific and easy to perform for detecting low numbers of T. pallidum in clinical blood specimens as a complementary to serology for syphilis diagnosis.展开更多
文摘We previously reported that many ingenol compounds derived from Euphoria kansui exhibit topoisomerase inhibitory activity. 20-O-ingenolEZ in these compounds exerted inhibitory effects on both topoisomerase II (topo II) activity and cell proliferative activity. Topoisomerase II inhibitors can be divided into the poison and catalytic inhibitor types and 20-O-ingenolEZ is a catalytic inhibitor and inhibits topo IIα through inhibition of ATPase activity, but induces topo II-mediated DNA damage and apoptosis in BLM-/- DT40 cells through the induction of the DNA damage checkpoint, similar to the poison type inhibitor adriamycin. The ATPase inhibitor of topo II ICRF-193 also showed poison-like characteristics in the same cell line. However, the inhibitory effects of ICRF-193 on the proliferation of BLM-/- DT40 cells differed from those of 20-O-ingenolEZ, as did the specificity of its inhibition of the proliferation of other cell lines. 20-O-ingenolEZ showed hypersensitive inhibition of the proliferation of MCF-7 cells and BLM-/- DT40 cells with mutated DNA repair-related genes.
基金Supported by Hainan Provincial Natural Science Foundation of China,High-level Talent Project(321RC587),Classification of sea snakes in the South Sea China based on molecular Systematics,morphology and climate modelSpecial Scientific Research Trial Production Project of Sanya City(2016KS05),Identification of sea snake species and construction of DNA barcoding based on molecular systematics.
文摘[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea snakes.[Methods]All COI and cytb gene sequences on GenBank were searched and downloaded.After the comparison with Mega software,clustering trees of MrBayes system were established.[Results]Interspecies distances were greater than intraspecies distances for the two genes.The topological structures of their molecular hierarchical clustering trees were clear,and the support rates were high.[Conclusions]Therefore,it is concluded that not the DNA barcode of each species must be gene COI.Cytb is more suitable in terms of the mitochondrial gene of sea snakes.
基金the Natural Scientific Foundation of China (NSFC3962526)National High-Technology Project-863 (102-10-01-04)
文摘AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method by using abundant double-stranded cDNA messages provided by two self-constructed cDNA libraries (Allitridi-treated and paternal HGC cell line BGC823 cells cDNA libraries respectively). Bam H I and Xho I restriction sites harbored in the library vector were used to select representations. Northern and Slot blots analyses were employed to identify the obtained difference products. RESULTS: Fragments released from the cDNA library vector after restriction endonuclease digestion acted as good marker indicating the appropriate digestion degree for library DNA. Two novel expressed sequence tags (ESTs) and a recombinant gene were obtained. Slot blots result showed a 8-fold increase of glia-derived nexin/protease nexin 1 (GDN/PN1) gene expression level and 4-fold increase of hepatitis B virus x-interacting protein (XIP) mRNA level in BGC823 cells after Allitridi treatment for 72h. CONCLUSION: Elevated levels of GDN/PN1 and XIP mRNAs induced by Allitridi provide valuable molecular evidence for elucidating the garlic's efficacies against neurodegenerative and inflammatory diseases. Isolation of a recombinant gene and two novel ESTs further show cDNA RDA based on cDNA libraries to be a powerful method with high specificity and reproducibility in cloning differentially expressed genes.
文摘Persistent infection wit h high-risk types of human papillomavirus(HPV) is known to cause cervical cancer;however,additional genetic and epigenetic alterations are required for progression from precancerous disease to invasive cancer.DNA methylation is an early and frequent molecular alteration in cervical carcinogenesis.In this review,we summarize DNA methylation within the HPV genome and human genome and identify its clinical implications.Methylation of the HPV long control region(LCR) and L1 gene is common during cervical carcinogenesis and increases with the severity of the cervical neoplasm.The L1 gene of HPV16 and HPV18 is consistently hypermethylated in invasive cervical cancers and can potentially be used as a clinical marker of cancer progression.Moreover,promoters of tumor suppressor genes(TSGs) involved in many cellular pathways are methylated in cervical precursors and invasive cancers.Some are associated with squamous cell carcinomas,and others are associated with adenocarcinomas.Identification of methylated TSGs in Pap smear could be an adjuvant test in cervical cancer screening for triage of women with high-risk HPV,atypical squamous cells of undetermined significance,or low grade squamous intraepithelial lesion(LSIL).However,consistent panels must be validated for this approach to be translated to the clinic.Furthermore,reversion of methylated TSGs using demethylating drugs may be an alternative anticancer treatment,but demethylating drugs without toxic carcinogenic and mutagenic properties must be identified and validated.
基金supported by the National Natural Science Foundation of China (NSFC31872105 and 31801862)the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences, and the Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture and Rural Affairs, China
文摘DNA methylation plays an important role in plant growth and development,and in regulating the activity of transposable elements(TEs).Research on DNA methylation-related(DMR)genes has been reported in Arabidopsis,but little research on DMR genes has been reported in Brassica rapa and Brassica oleracea,the genomes of which exhibit significant differences in TE content.In this study,we identified 78 and 77 DMR genes in Brassica rapa and Brassica oleracea,respectively.Detailed analysis revealed that the numbers of DMR genes in different DMR pathways varied in B.rapa and B.oleracea.The evolutionary selection pressure of DMR genes in B.rapa and B.oleracea was compared,and the DMR genes showed differential evolution between these two species.The nucleotide diversity(π)and selective sweep(Tajima’s D)revealed footprints of selection in the B.rapa and B.oleracea populations.Transcriptome analysis showed that most DMR genes exhibited similar expression characteristics in B.rapa and B.oleracea.This study dissects the evolutionary differences and genetic variations of the DMR genes in B.rapa and B.oleracea,and will provide valuable resources for future research on the divergent evolution of DNA methylation between B.rapa and B.oleracea.
文摘Bicoid is one of the important Drosophila maternal genes involved in the control of embryo polarity and larvae segmentation. To clone and characterize the rice bicoid-related genes, one cDNA clone, Rb24 (EMBL accession number: AJ2771380), was isolated by screening of rice unmature seed cDNA library. Sequence analysis indicates that Rb24 contains a putative amino acid sequence, which is homologous to unique 8 amino acids sequence within Drosophila bicoid homeodomain (50% identity, 75% similarity) and involves a lys-9 in putative helix 3. Northern blot analysis of rice RNA has shown that this sequence is expressed in a tissue-specific manner. The transcript was detected strongly in young panicles, but less in young leaves and roots. This results are further confirmed with paraffin section in situ hybridization. The signal is intensive in rice globular embryo and located at the apical tip of the embryo, then, along with the development of embryo, the signal is getting reduced and transfers into both sides of embryo. The existence of bicoid-related sequence in rice embryo and the similarity of polar distribution of bicoid and Rb24 mRNA in early embryo development may implicates a conserved maternal regulation mechanism of body axis presents in Drosophila and in rice.
基金Supported by a grant from the National Natural Science Foundation of China (No.30672713)
文摘Objective： The aim of the study was to observe the expressions of genes related to genome stability and DNA repair in the members of nasopharyngeal carcinoma （NPC） clustedng families. Methods： In the Zhongshan City where there is highly incidence rate of NPC, we chose the members of the NPC clustering families as objects, and the patients of nasopharyngitis and NPC as the control group. We isolated the RNA from the nasopharyngeal tissue, and synthesized its cRNA, the genome stability and DNA repair genes chip technique, chemiluminescent detection and real-time fluorescence quantita- tive technique were used to examine the genome stability and DNA repair genes in the nasopharyngeal tissue. Results： More genome stability and DNA repair genes were up-regulated in the members of the NPC clustering families than the NPC patients, and the range of up-regulated was high, with the over up-regulated 100 times genes including TEP1, MSH4, PMS2LI. Fewer genome stability and DNA repair genes were down-regulated in the members of the NPC clustering families than the NPC patients, the ubiquitin genes almost were down-regulated, the results also could be confirmed by real-time fluorescence quantitative PCR. Conclusion： There are specially expression character of genome stability and DNA repair genes in the members of NPC clustering families.
文摘Bacillus thuringiensis (Bt) strain C002 contains crylAa, cry2Ab, crylCa insecticidal crystal genes and an unkown gene cryX, among which crylCa is located in a 6 -9 kb EcoR I fragment of the chromosomal DNA. The total DNA and the plasmids DNA libraries of C002 were constructed in Bt-E. coli shuttle plasmid pHT315 by inserting 6 - 9 kb chromosomal and plasmid DNA fragments prepared respectively with EcoR I complete and 5au3A I partial digestion. On the basis of every 50 transformants pooled together from 5-10 tubes, the pools containing about 2 000 transformants from the plasmids DNA library and 400 transformants from the total DNA library were rapidly screened by PCR-RFLP. Clones containing crylAa, cryX, crylCa , and cry2Ab were isolated and named as pHT-1Aa, pHT-X, pHT-1Ca and pHT-2Ab respectively. Restriction analysis indicated that pHT-1Aa, pHT-1Ca and pHT-2Ab had the typical physical map of the homologous cry genes. Furthermore, each plasmid was transferred into Bt acrystalliferous strain cryB- by eletropora-tion. SDS-PAGE result showed that transformant of pHT-1Ca expressed 130 kDa protein and bioassay result proved its high toxicity against Spodotera exigua 1st instar larvae with 100% corrected motality.
文摘Microsatellite instability (MSI) is used as a molecular marker for defective DNA mismatch repair (MMR) genes.We report here alterations of MSI in 15 malignant astrocytomas (WHO grade Ⅲ) and glioblastomas (GBM; WHO grade Ⅳ) of pediatric patients (2-21 years) and 12 GBM from adults (44-68 years) by comparative analysis of BAT25/BAT26 loci and 10 other microsatellite markers. High-level microsatellite instability (MSI-H) occurred in 4 of the 15 pediatric cases (26.7%) and in 1 of the 12 adult GBM cases (8.3%). Low-level mi-
基金supported by the National Natural Science Foundation of China(Grant Nos.91531304 and 31525018)"Strategic Priority Research Program" of the Chinese Academy of Sciences(Grant No.XDA08020202)+1 种基金a special program from the State Key Laboratory of Plant Cell and Chromosome Engineering(PCCE-TD-2012-01)National Key Basic Research Program(No.2013CB835200)
文摘The chloroplast is one of the most important organs in plants because of its essential role in photosynthesis.Studies have shown that the chloroplast was once a free-living cyanobacteria and was integrated into the host species through endosymbiosis（Goksoyr.1967）.after which a large number of its genes had been donated to the host nuclear genome（Heins and Soll, 1998）.
文摘When the loop-mediated isothermal amplification(LAMP)assay is used for detecting target genes,DNA extraction is unnecessary in many cases.Simple pretreatment(e.g.heating)is enough to obtain rather sensitive responses.Even test samples without any pretreatment can be used as template.This feature suggests that LAMP is superior to PCR in developing point-of-care test strategies.In this study,using Stx1 gene from E.coli as model,we verified that viable cells,dead cells and extracellular DNA could function as template in the LAMP assay.In the incubation at 63℃,viable bacteria in the LAMP reaction mixture lysed completely within 2 min,providing DNA template for nucleic acid amplification.The Stx1 gene in diluted culture medium,spiked tap water,spiked seawater and real seawater all could be detected,with or without the step of DNA extraction.We found that the complex substances in real sample(e.g.natural seawater)exhibited considerable inhibitory effect on the sensitivity of the LAMP assay.These outcomes are meaningful for building a point-of-care strategy by employing the LAMP assay for environmental monitoring,bio-resource surveys,food safety,etc.in particular those based on environmental DNA.
文摘Objective: To investigate the effects of DNA methylation and histone deacetylase inhibitors in the re-expression of P16 and RASSIF1A of QBC939. Methods: The QBC939 cells were treated with hydralazine and valproate either alone or combined, and the control group was added with RPIM-1640 culture medium. After 48 h, the expression of P16 and RASSF1A genes were evaluated by reverse transcription-PCR, Western blot, and the methylation status of the two genes were detected with MSP (methylation specific PCR). Results: Hydralazine and valproate could induce demethylation of the promoter region of the two genes, and could make them re-active. The expressions of P16 and RASSF1A of cells treated with both drugs were higher than that of the cells treated with either hydralazine or valproate (P < 0.01). There was no RASSF1A gene, and few P16 gene expressing in the control group. The demethylation effect could be found in the groups treated with hydralazine or both drugs, whereas no demethylation effect happened in the valproate group. Conclusion: The two drugs could synergistically re-express P16 and RASSF1A genes silenced in QBC939, and they exerted a great anti-tumour effect on QBC cells.
文摘Esophageal cancer(EC)was an aggressive malignant neoplasm characterized by high morbidity and poor prognosis.Identifying the changes in DNA damage repair genes helps to better understand the mechanisms of carcinoma progression.In this study,by comparing EC samples and normal samples,we found a total of 132 DDR expression with a significant difference.Moreover,we revealed higher expression of POLN,PALB2,ATM,PER1,TOP3B and lower expression of HMGB1,UBE2B were correlated to longer OS in EC.In addition,a prognostic risk score based on 7 DDR gene expression(POLN,HMGB1,TOP3B,PER1,UBE2B,ATM,PALB2)was constructed for the prognosis of EC.Meanwhile,EC cancer samples were divided into 3 subtypes based on 132 DDR genes expressions.Clinical profile analysis showed cluster C1 and C2 showed a similar frequency of T2,which was remarked higher than that in cluster 3.Moreover,we found the immune cell inflation levels were significantly changed in different subtypes of EC.The infiltration levels of T cell CD8+,B cell and NK cells were greatly higher in cluster 2 than that in cluster 1 and cluster 3.The results showed T cell CD4+infiltration levels were dramatically higher in cluster 1 than that in cluster 2 and cluster 3.Finally,we perform bioinformatics analysis of DEGs among 3 subtypes of EC and found DDR genes may be related to multiple signaling,such as Base excision repair,Cell cycle,Hedgehog signaling pathway,and Glycolysis/Gluconeogenesis.These results showed DDR genes may serve as new target for the prognosis of EC and prediction of the potential response of immune therapy in EC.
文摘5-methylcytosine (m5C) as a rare base exists in eucaryotic genomes, it is a normal constituent of many eucaryotic DNA, whose existence is a character of eucaryotic DNA. In the regular physiological conditions, cytosine residue of eucaryotic DNA is methylated to be popular. Up to the present, many people consider that the m5C may be mutation hotspots by the m5C deamination leading to gene mutation. Our theoretical investigations indicated that the spontaneous mutation caused by the transition of G - C-A - T, in eukaryotic DNA, may be a result caused by the tautomer changing base pairs and may also be caused by other factor actions, however it could not be caused by the deamination of m5C.
文摘Objective: To develop a sensitive, specific and simple method for detection of extremely low numbers of T. pallidum in clinical specimens, as a significant addition to the serologic tests for syphilis diagnosis. Methods: Double-tube nested PCR(DN-PCR) and single-tube nested PCR(SN-PCR) assays were performed to amplify specific fragments of the DNA poly-merase I gene(polA) of T. pallidum. Sensitivity and specificity of the two PCR assays were tested. Eighty-six whole blood specimens from persons with suspected syphilis were detected by the two nested PCR methods. The TPPA test was used as a comparison for detecting syphilis in sera from corresponding patients. Results: Only specific amplicons could be obtained during amplification of the T. pallidum polA gene and the detection limit was approximately 1 organism when analyzed on gel by the two PCR methods. Of 86 clinical specimens, 62 were positive by TPPA. Of these, 54 and 51 were positive by the DN-PCR and SN-PCR, respectively, which does not represent a statistically significant difference between the two PCR tests. Of 24 TPPA-negative specimens, 5 were positive by both DN-PCR assay and SN-PCR assay. Conclusion: The SN- polA PCR method is extremely sensitive, specific and easy to perform for detecting low numbers of T. pallidum in clinical blood specimens as a complementary to serology for syphilis diagnosis.
