Objective:To establish a TaqMan-MGB probe-based method for detecting the polymorphic loci C677T and A1298C of the MTHFR gene.Methods:Specific primers and TaqMan-MGB probes targeting the C677T and A1298C polymorphic loci of the MTHFR gene were designed and optimized based on the gene sequence information.A real-time quantitative PCR detection system was established.Gradient dilution experiments were conducted to determine the limit of detection,and reproducibility experiments were performed to evaluate detection consistency.Specificity was validated using wild-type and mutant plasmid templates.The method was applied to detect 56 clinical samples,and its accuracy and practicality were assessed through comparison with traditional Sanger sequencing.Results:The TaqMan-MGB probe method demonstrated high specificity for detecting the C677T and A1298C loci,with no cross-reactivity between wild-type and mutant probes,enabling accurate genotype differentiation.Sensitivity experiments revealed detection limits of 1.13 × 103 copies/μL for C677T and 8.39 × 101 copies/μL for A1298C.Reproducibility experiments showed coefficients of variation below 1％,indicating stable and reliable results.Among the 56 clinical samples,the overall detection rate for the C677T locus was 86.99％,and for the A1298C locus,it was 97.92％.The TaqMan-MGB method exhibited good concordance with Sanger sequencing results.Conclusion:The TaqMan-MGB method exhibits high specificity,sensitivity,and excellent reproducibility in detecting the polymorphic loci C677T and A1298C of the MTHFR gene,making it suitable for rapid detection in large-scale clinical samples.This method provides an effective molecular diagnostic tool for the early diagnosis and prevention of folate-related diseases.

This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.

Objective:To investigate the effects of TP53 genetic status(wild-type/mutated/null)on the drug resistance of decitabine(DAC)in myelodysplastic syndromes(MDS)and identify key resistance-associated genes.Methods:Two myeloid cell lines with distinct TP53 status(M-07e:wild-type;SKM-1:mutated;)were treated with gradient DAC concentrations(0-10 μmol/L)for 0-72 h.Cell viability was detected by CCK-8 assay.RNA-Seq transcriptomics,and methylation profiling were integrated to analyze differentially expressed genes.Results:Decitabine(DAC)treatment induced time-and dose-dependent inhibition of cell viability in CCK-8 assays,with SKM-1 cells exhibiting the highest resistance(IC50=5 μmol/L vs M-07e=0.5 μmol/L,P＜0.01).Transcriptomic analysis revealed 662 upregulated and 452 downregulated genes in DAC-treated M-07e cells,while SKM-1 cells showed 515 upregulated and 73 downregulated genes.By proteomic profiling,117 upregulated and 136 downregulated proteins were identified in M-07e cells,while 91 upregulated and 46 downregulated proteins were identified in SKM-1 cells following DAC exposure.Through integrated analysis of upregulated genes and proteins expression profiles,181 candidate genes were screened out,while methylation studies identified 884 hypomethylated genes with high-sensitivity loci and CpG density.Notably,31 genes overlapped between these datasets,and functional annotation indicated these drug-resistance-associated genes are primarily involved in positive regulation of cell differentiation,negative regulation of binding processes,and negative regulation of cellular component organization.Conclusion:TP53 mutations drive DAC resistance via epigenetic reprogramming.Targeting these genes may improve outcomes in TP53-mutated MDS.

Objective:To investigate the incidence,clinical characteristics,and complications of Torque teno virus(TTV)in children after hematopoietic stem cell transplantation(HSCT).Methods:A total of 40 children with hematological diseases who underwent HSCT were selected,and metagenomic next-generation sequencing(mNGS)technology was used to detect the gene sequences of pathogenic microorganisms in the blood.Combined with clinical data,the characteristics of TTV infection were analyzed.Results:Among the 40 pediatric patients post-HSCT,the TTV positive rate was 42.5％(17/40).There were no statistically significant differences between the TTV-positive group and the TTV-negative group in sex,age,white blood cell count(WBC),red blood cell count(RBC),hemoglobin,platelet count,neutrophil count,lymphocyte count,and high-sensitivity C-reactive protein(all P＞0.05).The incidence of TTV infection was significantly higher in children who underwent haploidentical HSCT and in those with bone marrow stem cells(BMSC)as the transplant source(P＜0.05).However,there were no significant differences in the TTV infection rate among patients with different disease types,different HLA matching statuses,or different engraftment times of neutrophils and platelets(all P＞0.05).Among 17 children infected with TTV,13(76.5％)had co-infections with other viruses,mainly including cytomegalovirus(58.8％,10/17),human polyomavirus(41.2％,7/17),and Epstein-Barr virus(17.6％,3/17).In children with TTV infection,the most common complications were sepsis(82.4％),graft-versus-host disease(GVHD)(70.6％),pulmonary infection(41.2％),and hemorrhagic cystitis(17.6％).The incidence of GVHD in the TTV-positive group was significantly higher than that in the TTV-negative group(P＜0.05).Conclusion:TTV infection is common in children undergoing HSCT,and it is prone to be complicated with cytomegalovirus infection and GVHD,which has an important influence on the clinical outcomes.

Objective:To investigate the effects of TP53 genetic status(wild-type/mutated/null)on the drug resistance of decitabine(DAC)in myelodysplastic syndromes(MDS)and identify key resistance-associated genes.Methods:Two myeloid cell lines with distinct TP53 status(M-07e:wild-type;SKM-1:mutated;)were treated with gradient DAC concentrations(0-10 μmol/L)for 0-72 h.Cell viability was detected by CCK-8 assay.RNA-Seq transcriptomics,and methylation profiling were integrated to analyze differentially expressed genes.Results:Decitabine(DAC)treatment induced time-and dose-dependent inhibition of cell viability in CCK-8 assays,with SKM-1 cells exhibiting the highest resistance(IC50=5 μmol/L vs M-07e=0.5 μmol/L,P＜0.01).Transcriptomic analysis revealed 662 upregulated and 452 downregulated genes in DAC-treated M-07e cells,while SKM-1 cells showed 515 upregulated and 73 downregulated genes.By proteomic profiling,117 upregulated and 136 downregulated proteins were identified in M-07e cells,while 91 upregulated and 46 downregulated proteins were identified in SKM-1 cells following DAC exposure.Through integrated analysis of upregulated genes and proteins expression profiles,181 candidate genes were screened out,while methylation studies identified 884 hypomethylated genes with high-sensitivity loci and CpG density.Notably,31 genes overlapped between these datasets,and functional annotation indicated these drug-resistance-associated genes are primarily involved in positive regulation of cell differentiation,negative regulation of binding processes,and negative regulation of cellular component organization.Conclusion:TP53 mutations drive DAC resistance via epigenetic reprogramming.Targeting these genes may improve outcomes in TP53-mutated MDS.

Objective:To investigate the incidence,clinical characteristics,and complications of Torque teno virus(TTV)in children after hematopoietic stem cell transplantation(HSCT).Methods:A total of 40 children with hematological diseases who underwent HSCT were selected,and metagenomic next-generation sequencing(mNGS)technology was used to detect the gene sequences of pathogenic microorganisms in the blood.Combined with clinical data,the characteristics of TTV infection were analyzed.Results:Among the 40 pediatric patients post-HSCT,the TTV positive rate was 42.5％(17/40).There were no statistically significant differences between the TTV-positive group and the TTV-negative group in sex,age,white blood cell count(WBC),red blood cell count(RBC),hemoglobin,platelet count,neutrophil count,lymphocyte count,and high-sensitivity C-reactive protein(all P＞0.05).The incidence of TTV infection was significantly higher in children who underwent haploidentical HSCT and in those with bone marrow stem cells(BMSC)as the transplant source(P＜0.05).However,there were no significant differences in the TTV infection rate among patients with different disease types,different HLA matching statuses,or different engraftment times of neutrophils and platelets(all P＞0.05).Among 17 children infected with TTV,13(76.5％)had co-infections with other viruses,mainly including cytomegalovirus(58.8％,10/17),human polyomavirus(41.2％,7/17),and Epstein-Barr virus(17.6％,3/17).In children with TTV infection,the most common complications were sepsis(82.4％),graft-versus-host disease(GVHD)(70.6％),pulmonary infection(41.2％),and hemorrhagic cystitis(17.6％).The incidence of GVHD in the TTV-positive group was significantly higher than that in the TTV-negative group(P＜0.05).Conclusion:TTV infection is common in children undergoing HSCT,and it is prone to be complicated with cytomegalovirus infection and GVHD,which has an important influence on the clinical outcomes.

This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.

Objective:To establish a TaqMan-MGB probe-based method for detecting the polymorphic loci C677T and A1298C of the MTHFR gene.Methods:Specific primers and TaqMan-MGB probes targeting the C677T and A1298C polymorphic loci of the MTHFR gene were designed and optimized based on the gene sequence information.A real-time quantitative PCR detection system was established.Gradient dilution experiments were conducted to determine the limit of detection,and reproducibility experiments were performed to evaluate detection consistency.Specificity was validated using wild-type and mutant plasmid templates.The method was applied to detect 56 clinical samples,and its accuracy and practicality were assessed through comparison with traditional Sanger sequencing.Results:The TaqMan-MGB probe method demonstrated high specificity for detecting the C677T and A1298C loci,with no cross-reactivity between wild-type and mutant probes,enabling accurate genotype differentiation.Sensitivity experiments revealed detection limits of 1.13 × 103 copies/μL for C677T and 8.39 × 101 copies/μL for A1298C.Reproducibility experiments showed coefficients of variation below 1％,indicating stable and reliable results.Among the 56 clinical samples,the overall detection rate for the C677T locus was 86.99％,and for the A1298C locus,it was 97.92％.The TaqMan-MGB method exhibited good concordance with Sanger sequencing results.Conclusion:The TaqMan-MGB method exhibits high specificity,sensitivity,and excellent reproducibility in detecting the polymorphic loci C677T and A1298C of the MTHFR gene,making it suitable for rapid detection in large-scale clinical samples.This method provides an effective molecular diagnostic tool for the early diagnosis and prevention of folate-related diseases.

Objective:To explore the optimal storage condition and time of umbilical cord blood from collection to preparation.Methods:Collect cord blood samples from 30 healthy newborns,with each new born's umbilical cord blood was divided into two parts on average.One part was stored in cold storage(4 ℃)and the other was stored at room temperature(20-24 ℃).Samples were taken at 24,36,48,60 and 72 h,respectively,total nucleated cells(TNC)count and TNC viability was analyzed.Flow cytometry was used to detect the ratio of viable CD34+cells to viable CD45+cells and viability of CD34+cells,and colony-forming unit-granulocyte-macrophage(CFU-GM)count was performed by hematopoietic progenitor cell colony culture.The change trend of each index over time was observed,and the differences in each index was compared between cold storage and room temperature storage under the same storage time.Results:The TNC count(r4℃=-0.9588,r20-24℃=-0.9790),TNC viability(r4℃=-0.9941,r20 24 ℃=-0.9970),CD34+cells viability(r4℃=-0.9932,r20-24℃=-0.9828)of cord blood stored in cold storage(4 ℃)and room temperature storage(20-24 ℃)showed a consistent downward trend with the prolongation of storage time.The percentage of viable CD34+cells(r4℃=0.9169,r20-24 ℃=0.7470)and CFU-GM count(r4℃=-0.2537,r20-24℃=-0.8098)did not show consistent trends.When the storage time was the same,the TNC count,TNC viability,CD34+cells viability and CFU-GM count of cord blood stored in cold storage were higher than those stored at room temperature.Under the same storage time(24,36,48,60 or 72 h),TNC viability in room temperature storage was significantly lower than that in cold storage(P＜0.001),but TNC count,percentage of viable CD34+cells and CFU-GM count were not significantly different between room temperature storage and cold storage.When stored at room temperature for 24 h and 36 h,the viability of CD34+cells was significantly lower than that in cold storage(P＜0.001,P＜0.01),when the storage time for 48,60 and 72 h,there was no significant difference in the CD34+cells viability between room temperature storage and cold storage.Conclusion:It is recommended that cord blood be stored in cold storage(4 ℃)from collection to preparation,and processed as soon as possible.

Aim To explore the effects of Huannao Yicong decoction(HYD)on the learning and memory ability and brain iron metabolism in APP/PS1 mice and the correlation of HAMP knockout mice and APP/PS1 double transgenic model mice.Methods The ex-periment was divided into five groups,namely,HAMP-/-group(6-month HAMP gene knockout mice),APP/PS1 group(6-month APP/PS1-double-transgenic mice),HAMP-/-+HYD,APP/PS1+HYD,and negative control group(6-month C57BL/6J mice),with six mice in each group.The dose was ad-ministered(13.68 g·kg-1 weight),and the other groups received distilled water for gavage once a day for two months.After the administration of the drug,the mice in each group were tested for learning and memory in the Morris water maze;Biochemical detec-tion was performed to detect iron ion content in each mouse brain;Western blot and RT-qPCR were carried out to analyze hippocampal transferrin(TF),transfer-rin receptor1(TFR1),membrane iron transporter1(FPN1)divalent metal ion transporter 1(DMT1)and β-amyloid protein(Aβ)protein and mRNA expression levels in each group.Results Compared with the normal group,both HAMP-/-mice and APP/PS1 mice had reduced the learning and memory capacity,in-creased iron content in brain tissue,Aβ protein ex-pression increased in hippocampus of HAMP-/-group and APP/PS1 group mice(P＜0.01),the protein and mRNA expression of TF,TFR1 and DMT1 increased in hippocampal tissues of HAMP-/-and APP/PS1 groups(P＜0.01),and the FPN1 protein and mRNA expres-sion decreased(P＜0.01).Compared with the HAMP-and APP/PS1 groups,respectively,HAMP-/-+HYD group and APP/PS1+HYD group had improved learning and memory ability,decreased iron content,decreased Aβ protein expression(P＜0.01),decreased TF,TFR1,DMT1 protein and mR-NA expression(P＜0.01),and increased expression of FPN1 protein and mRNA(P＜0.01).Conclusions There is some association between HAMP-/-mice and APP/PS1 mice,HYD can improve the learning and memory ability of HAMP-/-and APP/PS1 mice and reduce the Aβ deposition.The mechanism may be related to the regulation of TF,TFR1,DMT1,FPN1 expression and improving brain iron overload.