The class 1 integron and complex gene cassettes among different species of clinical isolates in northern China were characterized in this study. 383 clinical isolates were obtained from northern China, and class 1 int...The class 1 integron and complex gene cassettes among different species of clinical isolates in northern China were characterized in this study. 383 clinical isolates were obtained from northern China, and class 1 integrons containing gene cassettes widely distributed among gram negative clinical isolates was observed. We find that the class 1 integron showed positive correlation with multidrug resistance phenotype of gram negative bacteria. In addition, we find that isolates belonged to one species harbored different types of gene cassette arrays, while same types of gene cassette arrays were observed in different species of isolates. The diversity of gene cassette arrays among the isolates indicated the complexity of multidrug resistance in clinical isolates in northern China.展开更多
Pseudomonas aeruginosa is one of the most important opportunistic human pathogens worldwide. High prevalence of Multi Drug Resistant P. aeruginosa (MDRPa) in Iran is a serious problem for antimicrobial therapy. Severa...Pseudomonas aeruginosa is one of the most important opportunistic human pathogens worldwide. High prevalence of Multi Drug Resistant P. aeruginosa (MDRPa) in Iran is a serious problem for antimicrobial therapy. Several studies have reported the MDRPa in Europe and Asia. Due to the use of broad-spectrum antibiotics, bacterial resistance is increasing in Iran, located in Middle East. The present cross-sectional study was designed to investigate the prevalence of class1 integron, resistance gene cassettes and antimicrobial susceptibility profiles among isolates of P. aeruginosa in Al-Zahra Hospital, Isfahan City, central part of Iran from Jan-Sep 2014. The aim of this study was to determine the antimicrobial susceptibility, the prevalence of Class1 integron, resistance gene a measuring in Iran. A total of 231 P. aeruginosa isolates were collected from clinical specimens including urine (50.6%), tracheal tube (25.5%), wound (13.4%), blood (6.1%), catheter (2.2%), cerebrospinal fluid (1.7%) and sputum (0.4%) isolates from hospitalized patients (mean age: 50.27 ± 24.12 years).The majority of patients (68%) were male. Isolates were collected from different parts of the hospital as follows: ICU, Internal Medicine, Emergency care, Pediatrics, Nephrology, Transplant Center, General surgery and Infectious. Revealed data show a high rate of MDR P. aeruginosa isolates in the studied area;also, the result signifies the spread of aadA6 among clinical isolates in hospitalized patients.展开更多
Objective: To construct the small interfering RNA(siRNA) expression cassettes (SECs) targeting activated K-ras gene sequence and investigate the effects of SECs on K-ras gene in human pancreatic cancer cell line MIAPa...Objective: To construct the small interfering RNA(siRNA) expression cassettes (SECs) targeting activated K-ras gene sequence and investigate the effects of SECs on K-ras gene in human pancreatic cancer cell line MIAPaCa-2. Methods: Three different sites of SECs were constructed by PCR. The K1/siRNA, K2/siRNA and K3/siRNA were located at the site 194, 491 and 327, respectively. They were transfected into MiaPaCa-2 cells by liposome to inhibit the expression of activated K-ras. In the interfering groups of site 194,491, we observed the cytopathic effect of confluent MiaPaCa-2 cells after they were incubated for 48 hours, and detected the apoptosis in cells by FACS, then we tested the alternation of K-ras gene in confluent MiaPaCa-2 cells by RT-PCR,immunofluorescence and western blot, respectively. Results: Introductions of the K1/siRNA and K2/siRNA against K-ras into MiaPaCa-2 cells led to cytopathic effect, slower proliferation and increased apoptosis, while the appearances of control MiaPaCa-2 cells remained well. The number of apoptotic cells increased compared with control cells. RT-PCR,immunofluorescence and western blot showed the effects of inhibited expression of activated K-ras gene by RNA interference in the K1/siRNA and K2/siRNA groups. We also found that the introduction of K3/siRNA had no effect on MiaPaCa-2 cells. Conclusion: K1/siRNA and K2/siRNA can inhibit the expression of activated K-ras and decrease the growth of MiaPaCa-2 cells, while K3/siRNA has no such effect, demonstrating that the suppression of tumor growth by siRNA is sequence-specific. We conclude that K-ras is involved in maintenance of tumor growth of human pancreatic cancer, and SECs against K-ras expression may be a powerful tool to be used therapeutically against human pancreatic cancer.展开更多
The coagulase-negative staphylococci (CoNS) have long been considered to be low pathogenicity. The possibility of a horizontal transfer of resistance and virulence genes from S. aureus to CoNS could increase the patho...The coagulase-negative staphylococci (CoNS) have long been considered to be low pathogenicity. The possibility of a horizontal transfer of resistance and virulence genes from S. aureus to CoNS could increase the pathogenicity of these bacteria. The objective of this work is to contribute to a better knowledge of the pathogenicity of (CoNS) strains isolated from surfaces and medico-technical materials of the University Hospital of Abomey-Calavi/Sô-Ava. Seventy strains of CoNS isolated from surfaces and medico-technical materials of the University Hospital of Abomey-Calavi were tested for methicillin resistance. The resistance to methicillin was evaluated phenotypically by the resistance of the strains to cefoxitin and then confirmed by the search for the mecA gene using PCR. The genes encoding staphylococcal chromosomal cassette (SCCmec) types I, II and III originally found in S. aureus were tested in CoNS by multiplex PCR using specific primers. All the strains studied showed resistance to methicillin. However, only 28.5% (20/70) carried the mecA gene. SCCmec was identified in only 17.14% (12/70) of these strains. Four strains carried mecA gene as well as one of the three types of SCCmec searched. SCCmec types I, II and III were identified in CoNS strains studied. SCCmec type I was the most frequent chromosomal cassette in mecA<sup>+</sup> strains, only or in association with another SCCmec. The study also revealed methicillin-resistant strains carrying SCCmec lacking the mecA gene. Finally, 60% (12/20) of the strains were found to be non-typeable. Our results show that CoNS strains present a high resistance to methicillin and the source of this resistance in the CoNS of our study is not only the mecA gene. There is also a high diversity of SCCmec, justified by a large number of non-typeable CoNS strains. The mecA<sup>−</sup> SCCmec<sup>+</sup> methicillin-resistant strains deserve to be sequenced for further studies.展开更多
Adenosine triphosphate(ATP)-binding cassette(ABC)transporter systems are divided into importers and exporters that facilitate the movement of diverse substrate molecules across the lipid bilayer,against the concentrat...Adenosine triphosphate(ATP)-binding cassette(ABC)transporter systems are divided into importers and exporters that facilitate the movement of diverse substrate molecules across the lipid bilayer,against the concentration gradient.These transporters comprise two highly conserved nucleotide-binding domains(NBDs)and two transmembrane domains(TMDs).Unlike ABC exporters,prokaryotic ABC importers require an additional substrate-binding protein(SBP)as a recognition site for specific substrate translocation.The discovery of a large number of ABC systems in bacterial pathogens revealed that these transporters are crucial for the establishment of bacterial infections.The existing literature has highlighted the roles of ABC transporters in bacterial growth,pathogenesis,and virulence.These roles include importing essential nutrients required for a variety of cellular processes and exporting outer membrane-associated virulence factors and antimicrobial substances.This review outlines the general structures and classification of ABC systems to provide a comprehensive view of the activities and roles of ABC transporters associated with bacterial virulence and pathogenesis during infection.展开更多
BACKGROUND ATP-binding cassette subfamily B member 4(ABCB4)deficiency is associated with cholestatic liver disease primarily because of missense mutations,and many variants remain unidentified.Here,we validate the pat...BACKGROUND ATP-binding cassette subfamily B member 4(ABCB4)deficiency is associated with cholestatic liver disease primarily because of missense mutations,and many variants remain unidentified.Here,we validate the pathogenicity and mechanism of ABCB4 variants in clinical and in vitro trials,hypothesizing that these variants are responsible for impaired biliary function and contribute to the development of cholestatic liver diseases.AIM To clarify the functional features and pathogenicity of ABCB4 variants.METHODS Clinical data were collected from five patients with cholestatic liver disease that was initially not detected by routine examinations.Later,whole-exome sequencing confirmed ABCB4 variants and the patients were treated from January 2017 to December 2023.Pathogenic mechanisms were analyzed using bioinformatics tools,and a cell model in vitro was established to investigate ABCB4 mRNA expression,multidrug resistance protein 3(MDR3)expression,cellular localization,and phosphatidylcholine secretion.Results were compared using Student's t-tests.RESULTS Five missense variants(c.1757T>A,c.1865G>A,c.2362C>T,c.2777C>T and c.3250C>T),one intron variant(c.537-32G>T),and one synonymous(c.C504T)variant were identified.Three of the five patients had various degrees of cholestasis,two presented with liver cirrhosis,and all had elevated gamma-glutamyl transferase.Three of the four patients who underwent a liver biopsy had bile duct dilation,and one had gallstones.Two of the four patients had normal and reduced MDR3 immunohistochemical levels.Bioinformatic analysis indicated that these variants were likely pathogenic except c.C504T variant.None of the missense variants influenced subcellular MDR3 Localization in vitro.However,the c.1865G>A variant significantly decreased ABCB4 mRNA values,and all missense variants down-regulated phosphatidylcholine secretion.CONCLUSION This study uncovered new ABCB4 variants and emphasized the pathogenic potential of specific variants.The findings from five patients provided insight into the pathogenic mechanisms underlying ABCB4-related diseases.展开更多
Background:Oral squamous cell carcinoma(OSCC)is the most common head and neck malig-nancy with a low five-year survival rate.ATP-binding cassette subfamily B member 5(ABCB5)has been linked to tumorigenesis.However,its...Background:Oral squamous cell carcinoma(OSCC)is the most common head and neck malig-nancy with a low five-year survival rate.ATP-binding cassette subfamily B member 5(ABCB5)has been linked to tumorigenesis.However,its role in inducing OSCC remains unclear.Methods:Quantitative reverse transcription polymerase chain reaction(qRT-PCR),western blot,and immunocytochemistry(ICC)were performed to examine the level of ABCB5 in OSCC(CAL27 and HSC-3)and human oral keratinocyte(HOK).ABCB5 was knocked down in CAL27 cells using ABCB5-specific small interfering RNA(ABCB5 siRNA),and its contribution to migration,invasion,and epithelial-mesenchymal transition(EMT),a process by which epithelial cells lose their tight junction and acquire an increased migratory and invasive phenotype resembling that of mesenchymal cells,were evaluated by three-dimension and transwell migration and invasion assays,qRT-PCR and ICC.An in vivo OSCC model was established using 4-nitroquinoline-1-oxide(4NQO),a carcinogenic chemical that is commonly used to develop OSCC by destroying DNA synthesis and oxidative stress.Pathological alterations,ABCB5,and EMT markers were evaluated by H&E staining,immunohistochemistry,and qRT-PCR.Results:ABCB5 was significantly upregulated in CAL27 and HSC-3 cells as compared to HOK.Knockdown of ABCB5 significantly reduced the number of migrated and invaded CAL27 cells,accompanied by the significantly increased E-cadherin and decreased Vimentin and N-cadherin under Transforming growth factorβ(TGF-β)treatment.In vivo,as OSCC advanced,a notable rise in the expressions of ABCB5,N-cadherin,and Vimentin,while a statistical decrease in E-cadherin was demonstrated.Conclusion:ABCB5 promotes the migration,invasion,and EMT of OSCC.ABCB5 might be a new biomarker and potential therapeutic target for OSCC.展开更多
In this study,326 Escherichia coli isolates from food animals collected during the last four decades in China were characterized using antimicrobial susceptibility testing and screening for integrons/cassettes.Minimum...In this study,326 Escherichia coli isolates from food animals collected during the last four decades in China were characterized using antimicrobial susceptibility testing and screening for integrons/cassettes.Minimum inhibitory concentration(MIC) testing indicated that the antimicrobial resistance of E.coli has increased since the 1970s.The findings of this study present a warning to veterinary practitioners about the excessive use of antimicrobials,and suggest the necessity for surveillance and control of antimicrobial resistance in veterinary clinical medicine in China.展开更多
Colorectal cancer(CRC)ranks third in the number of cancers mainly because of the inability to diagnose it at an early stage.The pathogenesis of CRC is complicated,which is the result of the complex interaction of mult...Colorectal cancer(CRC)ranks third in the number of cancers mainly because of the inability to diagnose it at an early stage.The pathogenesis of CRC is complicated,which is the result of the complex interaction of multiple genetic and environmental factors.Currently,one of the main treatments for CRC is chemotherapy.But the primary cause of CRC treatment failure is drug resistance.The expression of cyclin-dependent kinase 9(CDK9)was correlated with elevated autophagy levels in colon cancer,and high expression of CDK9 indicates a poor prognosis in CRC.The incidence of autophagy and the expressions of Beclin 1 and ATP binding cassette transporter G2 are different in left and right colon cancer,and autophagy may be involved in the occurrence of chemotherapy resistance.In this article,the roles of CDK9,ATP binding cassette transporter G2 and Beclin 1 in CRC were elucidated,emphasizing the linkages among them and providing potential therapeutic targets of CRC.展开更多
Objective Glucocorticoid(GC)-induced adverse reactions(ARs)have been extensively studied due to their potential impact on patients’health.This study aimed to examine the potential correlation between two polymorphism...Objective Glucocorticoid(GC)-induced adverse reactions(ARs)have been extensively studied due to their potential impact on patients’health.This study aimed to examine the potential correlation between two polymorphisms[adenosine triphosphate-binding cassette B1(ABCB1)C3435T and plasminogen activator inhibitor-1(PAI-1)4G/5G]and various GC-induced ARs in nephrotic syndrome(NS)patients.Methods In this study,513 NS patients who underwent GC treatment were enrolled.Then,the patients were divided into two groups based on ABCB1 C3435T and PAI-14G/5G genotyping,and intergroup comparisons of clinicopathological data and GC-induced ARs were performed.Univariate and multivariate logistic analyses were subsequently conducted to identify potential risk factors for GC-induced ARs,and a nomogram was subsequently established and validated via the area under the ROC curve(AUC),calibration curve and decision curve analysis(DCA).Results We identified ABCB1 C3435T as an independent risk factor for the development of steroid-associated avascular necrosis of the femoral head(SANFH)(OR:2.191,95%CI:1.258–3.813,P=0.006)but not as a risk factor for the occurrence of steroid diabetes mellitus(S-DM).On the other hand,PAI-14G/5G was identified as an independent risk factor for the development of both SANFH(OR:2.198,95%CI:1.267–3.812,P=0.005)and S-DM(OR:2.080,95%CI:1.166–3.711,P=0.013).Notably,no significant correlation was found between the two gene polymorphisms and other GC-induced ARs.In addition,two nomograms were established and validated to demonstrate strong calibration capability and clinical utility.Conclusion Assessing ABCB1 C3435T and PAI-14G/5G before steroid treatment in NS patients could be useful for identifying patients at a high risk of developing SANFH and S-DM.展开更多
Objective To investigate the characteristic of integrons and the relationship between integrons and antimicrobial resistance in Shigella spp. Methods Ninety Shigella strains （83 S. flexneri and 7 S. sonnei） were iso...Objective To investigate the characteristic of integrons and the relationship between integrons and antimicrobial resistance in Shigella spp. Methods Ninety Shigella strains （83 S. flexneri and 7 S. sonnei） were isolated from the stools of patients in China. Susceptibility to 8 antimicrobials was tested for all isolated strains. PCR, RFLP and sequencing analysis of integrons were applied to all of them. Results High prevalence of multi‐drug resistance （95.6%） was identified. Of the isolates 79 （87.8%） carried integrase genes of class 1 integron （3.3%）, class 2 integron （10.0%） or both （74.4%）. No intI3 was detected in the tested isolates. The prevalence of intI2 was significantly higher in isolates with multi‐drug resistance to at least 3 antibiotics than that in isolates with resistance to 2 and less antibiotics （P0.05）. Gene cassettes dfrA17‐aadA5, dfrA12‐orfF‐aadA2 of class 1 integron and dfrA1‐sat1‐aadA1 of class 2 integron were identified. Conclusion The class 2 integron may play a role in the emergence of multi‐drug resistance in Shigella spp.展开更多
[Objective] This study aimed to investigate the multidrug resistance and prevalence of class I integrons in Salmonel a. [Method] Salmonel a strains were isolated from chicken farms in Shandong Province. Kauffmann-Whi...[Objective] This study aimed to investigate the multidrug resistance and prevalence of class I integrons in Salmonel a. [Method] Salmonel a strains were isolated from chicken farms in Shandong Province. Kauffmann-White classification method was employed to analyze the serotypes of Salmonel a strains. Minimum in-hibition concentration （MIC） of Salmonel a strains against 19 common antimicrobial drugs was analyzed determined with microdilution method. The class I integrons and carried drug resistance gene cassettes were detected by PCR. [Result] A total of 311 Salmonel a strains were isolated and classified into two serotypes, including 133 Salmonel a Indiana strains and 178 Salmonel a Enteritidis strains. Drug sensitivity test showed that the isolated Salmonel a strains were general y resistant to sulfadiazine, sulfamethoxazole, nalidixic acid, ampicil in, tetracycline, doxycycline and trimethoprim, with a multidrug resistance rate of 91.0% （283/311）; 99% strains were sensitive to amikacin and colistin. PCR assay indicated that the detection rate of class I integrons was 65.0% （202/311）; the positive rate of class I integrons in Salmonel a strains with multidrug resistance was 92.6%; among 202 positive strains, six strains carried gene cassette dfr17-aadA5. [Conclusion] According to the above results, class I integrons exist general y in Salmonel a and are closely associated with the multidrug resistance of Salmonel a strains.展开更多
Objective： MGMT protein expression has been associated with tumor resistance to alkylating agents. The objective of this paper is to construct the RNA interference vector which can specifically induce the expression ...Objective： MGMT protein expression has been associated with tumor resistance to alkylating agents. The objective of this paper is to construct the RNA interference vector which can specifically induce the expression silence of human DNA repair gene hMGMT. Methods： The hMGMT specific siRNA expression cassette was made by two steps PCR, linked with pUCI 9 to get pU6-MGMTi, co-transfected with pEGFP-CI into 16HBE and screened by G418. The MGMT mRNA and protein levels were detected by RT-PCR and Western Blot respectively. Results： hMGMT specific RNA interfere vector pU6-MGMTi was constructed successfully. In transfected 16HBE cells MGMT mRNA level could hardly be detected and the protein level was only 10% of control. Conclusion： MGMT specific RNAi expression cassette can effectively inhibit MGMT expression. MGMT silence cell line was built by co-transfection technology, which offered condition for studying the gene function of MGMT.展开更多
Particle bombardment transformation using minimal gene cassette （containing the promoter, open reading frame and terminator） is the novel trend in plant genetic transformation, and its use helps to alleviate the und...Particle bombardment transformation using minimal gene cassette （containing the promoter, open reading frame and terminator） is the novel trend in plant genetic transformation, and its use helps to alleviate the undesirable effects of plasmid vector backbone sequences on transgenic plants. In the present article, studies related to the hereditary behavior of bar gene cassette in T1 to T3 generations of the transgenic rice （Oryza sativa L.） lines transformed by particle bombardment have been discussed. The selectable marker bar gene cassette that integrated with the rice genome had multiple copies and showed complex segregation behaviors including the presence of ‘false homozygotes’, with abnormal segregation ratios ranging from 35：1 to 144：1 （Basta-resistant： sensitive plants） in their progenies. In five out of ten original transgenic lines, bar gene can be stably transmitted as a dominant gene to self-pollinated T2 progeny. The homozygotes were obtained in three transgenic lines in T1 generation regardless of the multiple-copy integration patterns of bar gene. Southern blotting analysis showed that multiple copies of bar gene cassette were linked, which formed transgene arrays in the host rice genome. The authors also observed stable transmission of integration patterns of bar gene cassette, as obtained from Southern blotting analysis, in the regularly segregated transgenic rice lines and loss of gene in an irregularly segregated transgenic line. The segregation behavior varied among the transgenic progenies that exhibited similar Southern hybridization patterns of bar gene. On the basis of these results, the multiple-copy integration, gene lost, and gene expres- sion interaction were the major reasons for the complex segregation behaviors of bar gene cassette in transgenic rice plants.展开更多
Drug resistance develops in nearly all patients with colon cancer, leading to a decrease in the therapeutic efficacies of anticancer agents. This review provides an up-to-date summary on over-expression of ATPbinding ...Drug resistance develops in nearly all patients with colon cancer, leading to a decrease in the therapeutic efficacies of anticancer agents. This review provides an up-to-date summary on over-expression of ATPbinding cassette(ABC) transporters and evasion of apoptosis, two representatives of transport-based and non-transport-based mechanisms of drug resistance, as well as their therapeutic strategies. Different ABC transporters were found to be up-regulated in colon cancer, which can facilitate the efflux of anticancer drugs out of cancer cells and decrease their therapeutic effects. Inhibition of ABC transporters by suppressing their protein expressions or co-administration of modulators has been proven as an effective approach to sensitize drug-resistant cancer cells to anticancer drugs in vitro. On the other hand, evasion of apoptosis observed in drug-resistant cancers also results in drug resistance to anticancer agents, especially to apoptosis inducers. Restoration of apoptotic signals by BH3 mimetics or epidermal growth factor receptor inhibitors and inhibition of cancer cell growth by alternative cell death pathways, such as autophagy, are effective means to treat such resistant cancer types. Given that the drug resistance mechanisms are different among colon cancer patients and may change even in a single patient at different stages, personalized and specific combination therapy is proposed to be more effective and safer for the reversal of drug resistance in clinics.展开更多
AIM: We shall construct the small interfering RNA (siRNA) expression cassette (SEC) targeting activated K-ras gene sequence, identify more effective siRNA sequence against K-ras gene in human pancreatic cancer cell li...AIM: We shall construct the small interfering RNA (siRNA) expression cassette (SEC) targeting activated K-ras gene sequence, identify more effective siRNA sequence against K-ras gene in human pancreatic cancer cell line MiaPaCa-2 by SEC and reveal the anti-cancer effects of RNA interference (RNAi) and its therapeutic possibilities. METHODS: Three different sites of SECs were constructed by PCR. K1/siRNA,K2/siRNA and K3/siRNA are located at sites 194,491 and 327, respectively. They were transfected into MiaPaCa-2 cells by liposome to inhibit the expression of activated K-ras. In the interfering groups of sites 194 and 491, we detected the apoptosis in cells by FACS after they were incubated for 48 h, then we tested the alternation of K-ras gene in MiaPaCa-2 cells by RT-PCR immunofluorescence, respectively. RESULTS: Introduction of the Kl/siRNA and K2/siRNA against K-ras into MiaPaCa-2 cells leads to increased apoptosis, and the number of apoptotic cells is increased compared with control cells. The tests of RT-PCR immunofluorescence show the effects of inhibiting expression of activated K-ras gene by RNA interference in the Kl/siRNA and K2/siRNA groups. We also find that the introduction of K3/siRNA has no effect on MiaPaCa-2 cells. CONCLUSION: Kl/siRNA and K2/siRNA can inhibit the expression of activated K-ras but K3/siRNA has no effect, demonstrating that Kl/siRNA and K2/siRNA are effective sequences against K-ras gene and K3/siRNA are not. We conclude that specific siRNA against K-ras expression may be a powerful tool to be used therapeutically against human pancreatic cancer.展开更多
Various previous studies have found a negative cor-relation between the risk of cardiovascular events and serum high-density lipoprotein(HDL) cholesterol levels. The reverse cholesterol transport, a pathway of choles-...Various previous studies have found a negative cor-relation between the risk of cardiovascular events and serum high-density lipoprotein(HDL) cholesterol levels. The reverse cholesterol transport, a pathway of choles-terol from peripheral tissue to liver which has several potent antiatherogenic properties. For instance, the particles of HDL mediate to transport cholesterol from cells in arterial tissues, particularly from atherosclerotic plaques, to the liver. Both ATP-binding cassette trans-porters(ABC) A1 and ABCG1 are membrane cholesterol transporters and have been implicated in mediating cholesterol effluxes from cells in the presence of HDL and apolipoprotein A-I, a major protein constituent of HDL. Previous studies demonstrated that ABCA1 and ABCG1 or the interaction between ABCA1 and ABCG1 exerted antiatherosclerotic effects. As a therapeutic approach for increasing HDL cholesterol levels, much focus has been placed on increasing HDL cholesterol levels as well as enhancing HDL biochemical functions. HDL therapies that use injections of reconstituted HDL, apoA-I mimetics, or full-length apoA-I have shown dramatic effectiveness. In particular, a novel apoA-I mi-metic peptide, Fukuoka University ApoA-I Mimetic Pep-tide, effectively removes cholesterol via specific ABCA1 and other transporters, such as ABCG1, and has an an-tiatherosclerotic effect by enhancing the biological func-tions of HDL without changing circulating HDL choles-terol levels. Thus, HDL-targeting therapy has significant atheroprotective potential, as it uses lipid transporter-targeting agents, and may prove to be a therapeutic tool for atherosclerotic cardiovascular diseases.展开更多
基金supported by Twelfth Five-Year Mega Project of Research on The Prevention and Control of HIV/AIDS,Viral Hepatitis Infectious Diseases 2013ZX10004-217 from the Ministry of Science and Technology,People’s Republic of China,the Project Sponsored by the Young Scholar Scientific Research Foundation of China CDC(No.2013A101)General Program of State Key Laboratory for Infections Disease Prevention and Control(No.2012SKLID205)
文摘The class 1 integron and complex gene cassettes among different species of clinical isolates in northern China were characterized in this study. 383 clinical isolates were obtained from northern China, and class 1 integrons containing gene cassettes widely distributed among gram negative clinical isolates was observed. We find that the class 1 integron showed positive correlation with multidrug resistance phenotype of gram negative bacteria. In addition, we find that isolates belonged to one species harbored different types of gene cassette arrays, while same types of gene cassette arrays were observed in different species of isolates. The diversity of gene cassette arrays among the isolates indicated the complexity of multidrug resistance in clinical isolates in northern China.
文摘Pseudomonas aeruginosa is one of the most important opportunistic human pathogens worldwide. High prevalence of Multi Drug Resistant P. aeruginosa (MDRPa) in Iran is a serious problem for antimicrobial therapy. Several studies have reported the MDRPa in Europe and Asia. Due to the use of broad-spectrum antibiotics, bacterial resistance is increasing in Iran, located in Middle East. The present cross-sectional study was designed to investigate the prevalence of class1 integron, resistance gene cassettes and antimicrobial susceptibility profiles among isolates of P. aeruginosa in Al-Zahra Hospital, Isfahan City, central part of Iran from Jan-Sep 2014. The aim of this study was to determine the antimicrobial susceptibility, the prevalence of Class1 integron, resistance gene a measuring in Iran. A total of 231 P. aeruginosa isolates were collected from clinical specimens including urine (50.6%), tracheal tube (25.5%), wound (13.4%), blood (6.1%), catheter (2.2%), cerebrospinal fluid (1.7%) and sputum (0.4%) isolates from hospitalized patients (mean age: 50.27 ± 24.12 years).The majority of patients (68%) were male. Isolates were collected from different parts of the hospital as follows: ICU, Internal Medicine, Emergency care, Pediatrics, Nephrology, Transplant Center, General surgery and Infectious. Revealed data show a high rate of MDR P. aeruginosa isolates in the studied area;also, the result signifies the spread of aadA6 among clinical isolates in hospitalized patients.
文摘Objective: To construct the small interfering RNA(siRNA) expression cassettes (SECs) targeting activated K-ras gene sequence and investigate the effects of SECs on K-ras gene in human pancreatic cancer cell line MIAPaCa-2. Methods: Three different sites of SECs were constructed by PCR. The K1/siRNA, K2/siRNA and K3/siRNA were located at the site 194, 491 and 327, respectively. They were transfected into MiaPaCa-2 cells by liposome to inhibit the expression of activated K-ras. In the interfering groups of site 194,491, we observed the cytopathic effect of confluent MiaPaCa-2 cells after they were incubated for 48 hours, and detected the apoptosis in cells by FACS, then we tested the alternation of K-ras gene in confluent MiaPaCa-2 cells by RT-PCR,immunofluorescence and western blot, respectively. Results: Introductions of the K1/siRNA and K2/siRNA against K-ras into MiaPaCa-2 cells led to cytopathic effect, slower proliferation and increased apoptosis, while the appearances of control MiaPaCa-2 cells remained well. The number of apoptotic cells increased compared with control cells. RT-PCR,immunofluorescence and western blot showed the effects of inhibited expression of activated K-ras gene by RNA interference in the K1/siRNA and K2/siRNA groups. We also found that the introduction of K3/siRNA had no effect on MiaPaCa-2 cells. Conclusion: K1/siRNA and K2/siRNA can inhibit the expression of activated K-ras and decrease the growth of MiaPaCa-2 cells, while K3/siRNA has no such effect, demonstrating that the suppression of tumor growth by siRNA is sequence-specific. We conclude that K-ras is involved in maintenance of tumor growth of human pancreatic cancer, and SECs against K-ras expression may be a powerful tool to be used therapeutically against human pancreatic cancer.
文摘The coagulase-negative staphylococci (CoNS) have long been considered to be low pathogenicity. The possibility of a horizontal transfer of resistance and virulence genes from S. aureus to CoNS could increase the pathogenicity of these bacteria. The objective of this work is to contribute to a better knowledge of the pathogenicity of (CoNS) strains isolated from surfaces and medico-technical materials of the University Hospital of Abomey-Calavi/Sô-Ava. Seventy strains of CoNS isolated from surfaces and medico-technical materials of the University Hospital of Abomey-Calavi were tested for methicillin resistance. The resistance to methicillin was evaluated phenotypically by the resistance of the strains to cefoxitin and then confirmed by the search for the mecA gene using PCR. The genes encoding staphylococcal chromosomal cassette (SCCmec) types I, II and III originally found in S. aureus were tested in CoNS by multiplex PCR using specific primers. All the strains studied showed resistance to methicillin. However, only 28.5% (20/70) carried the mecA gene. SCCmec was identified in only 17.14% (12/70) of these strains. Four strains carried mecA gene as well as one of the three types of SCCmec searched. SCCmec types I, II and III were identified in CoNS strains studied. SCCmec type I was the most frequent chromosomal cassette in mecA<sup>+</sup> strains, only or in association with another SCCmec. The study also revealed methicillin-resistant strains carrying SCCmec lacking the mecA gene. Finally, 60% (12/20) of the strains were found to be non-typeable. Our results show that CoNS strains present a high resistance to methicillin and the source of this resistance in the CoNS of our study is not only the mecA gene. There is also a high diversity of SCCmec, justified by a large number of non-typeable CoNS strains. The mecA<sup>−</sup> SCCmec<sup>+</sup> methicillin-resistant strains deserve to be sequenced for further studies.
基金supported by the Universiti Kebangsaan Malaysia under the Research University Grant(No.GUP-2020-030)awarded to Sylvia CHIENG.
文摘Adenosine triphosphate(ATP)-binding cassette(ABC)transporter systems are divided into importers and exporters that facilitate the movement of diverse substrate molecules across the lipid bilayer,against the concentration gradient.These transporters comprise two highly conserved nucleotide-binding domains(NBDs)and two transmembrane domains(TMDs).Unlike ABC exporters,prokaryotic ABC importers require an additional substrate-binding protein(SBP)as a recognition site for specific substrate translocation.The discovery of a large number of ABC systems in bacterial pathogens revealed that these transporters are crucial for the establishment of bacterial infections.The existing literature has highlighted the roles of ABC transporters in bacterial growth,pathogenesis,and virulence.These roles include importing essential nutrients required for a variety of cellular processes and exporting outer membrane-associated virulence factors and antimicrobial substances.This review outlines the general structures and classification of ABC systems to provide a comprehensive view of the activities and roles of ABC transporters associated with bacterial virulence and pathogenesis during infection.
基金Supported by the National Natural Science Foundation of China,No.81970454.
文摘BACKGROUND ATP-binding cassette subfamily B member 4(ABCB4)deficiency is associated with cholestatic liver disease primarily because of missense mutations,and many variants remain unidentified.Here,we validate the pathogenicity and mechanism of ABCB4 variants in clinical and in vitro trials,hypothesizing that these variants are responsible for impaired biliary function and contribute to the development of cholestatic liver diseases.AIM To clarify the functional features and pathogenicity of ABCB4 variants.METHODS Clinical data were collected from five patients with cholestatic liver disease that was initially not detected by routine examinations.Later,whole-exome sequencing confirmed ABCB4 variants and the patients were treated from January 2017 to December 2023.Pathogenic mechanisms were analyzed using bioinformatics tools,and a cell model in vitro was established to investigate ABCB4 mRNA expression,multidrug resistance protein 3(MDR3)expression,cellular localization,and phosphatidylcholine secretion.Results were compared using Student's t-tests.RESULTS Five missense variants(c.1757T>A,c.1865G>A,c.2362C>T,c.2777C>T and c.3250C>T),one intron variant(c.537-32G>T),and one synonymous(c.C504T)variant were identified.Three of the five patients had various degrees of cholestasis,two presented with liver cirrhosis,and all had elevated gamma-glutamyl transferase.Three of the four patients who underwent a liver biopsy had bile duct dilation,and one had gallstones.Two of the four patients had normal and reduced MDR3 immunohistochemical levels.Bioinformatic analysis indicated that these variants were likely pathogenic except c.C504T variant.None of the missense variants influenced subcellular MDR3 Localization in vitro.However,the c.1865G>A variant significantly decreased ABCB4 mRNA values,and all missense variants down-regulated phosphatidylcholine secretion.CONCLUSION This study uncovered new ABCB4 variants and emphasized the pathogenic potential of specific variants.The findings from five patients provided insight into the pathogenic mechanisms underlying ABCB4-related diseases.
基金the financial support from the Sichuan Science and Technology Program(No.2024JDRC0040)Luzhou Science and Technology Program(No.2023JYJ002,No.2023SYF139)+4 种基金Southwest Medical University Technology Program(No.2024ZKY018,No.2023ZD001,No.2024KQZX09)National Natural Science Foundation of China(No.82403404)NHCKey Laboratory ofNuclear TechnologyMedical Transformation(Mianyang Central Hospital)(No.2023HYX028)The Science and Technology Strategic Cooperation Programs of Deyang Stomatological Hospital and Southwest Medical University(No.2024DYKQXNYD03)the Affiliated Stomatology Hospital of Southwest Medical University Program(No.2022KQ03)。
文摘Background:Oral squamous cell carcinoma(OSCC)is the most common head and neck malig-nancy with a low five-year survival rate.ATP-binding cassette subfamily B member 5(ABCB5)has been linked to tumorigenesis.However,its role in inducing OSCC remains unclear.Methods:Quantitative reverse transcription polymerase chain reaction(qRT-PCR),western blot,and immunocytochemistry(ICC)were performed to examine the level of ABCB5 in OSCC(CAL27 and HSC-3)and human oral keratinocyte(HOK).ABCB5 was knocked down in CAL27 cells using ABCB5-specific small interfering RNA(ABCB5 siRNA),and its contribution to migration,invasion,and epithelial-mesenchymal transition(EMT),a process by which epithelial cells lose their tight junction and acquire an increased migratory and invasive phenotype resembling that of mesenchymal cells,were evaluated by three-dimension and transwell migration and invasion assays,qRT-PCR and ICC.An in vivo OSCC model was established using 4-nitroquinoline-1-oxide(4NQO),a carcinogenic chemical that is commonly used to develop OSCC by destroying DNA synthesis and oxidative stress.Pathological alterations,ABCB5,and EMT markers were evaluated by H&E staining,immunohistochemistry,and qRT-PCR.Results:ABCB5 was significantly upregulated in CAL27 and HSC-3 cells as compared to HOK.Knockdown of ABCB5 significantly reduced the number of migrated and invaded CAL27 cells,accompanied by the significantly increased E-cadherin and decreased Vimentin and N-cadherin under Transforming growth factorβ(TGF-β)treatment.In vivo,as OSCC advanced,a notable rise in the expressions of ABCB5,N-cadherin,and Vimentin,while a statistical decrease in E-cadherin was demonstrated.Conclusion:ABCB5 promotes the migration,invasion,and EMT of OSCC.ABCB5 might be a new biomarker and potential therapeutic target for OSCC.
基金supported by the National Key Project of Scientific and Technical Pillar Programs of China during the 10th Five-year Plan (Grant No 2004BA514A15-10)the 11th Five-year Plan (Grant No 2006BAK02A03-1)
文摘In this study,326 Escherichia coli isolates from food animals collected during the last four decades in China were characterized using antimicrobial susceptibility testing and screening for integrons/cassettes.Minimum inhibitory concentration(MIC) testing indicated that the antimicrobial resistance of E.coli has increased since the 1970s.The findings of this study present a warning to veterinary practitioners about the excessive use of antimicrobials,and suggest the necessity for surveillance and control of antimicrobial resistance in veterinary clinical medicine in China.
基金Supported by the National Natural Science Foundation of China,No.82272996the Science and Technology Program of Guangzhou,No.202206010081.
文摘Colorectal cancer(CRC)ranks third in the number of cancers mainly because of the inability to diagnose it at an early stage.The pathogenesis of CRC is complicated,which is the result of the complex interaction of multiple genetic and environmental factors.Currently,one of the main treatments for CRC is chemotherapy.But the primary cause of CRC treatment failure is drug resistance.The expression of cyclin-dependent kinase 9(CDK9)was correlated with elevated autophagy levels in colon cancer,and high expression of CDK9 indicates a poor prognosis in CRC.The incidence of autophagy and the expressions of Beclin 1 and ATP binding cassette transporter G2 are different in left and right colon cancer,and autophagy may be involved in the occurrence of chemotherapy resistance.In this article,the roles of CDK9,ATP binding cassette transporter G2 and Beclin 1 in CRC were elucidated,emphasizing the linkages among them and providing potential therapeutic targets of CRC.
基金supported by the General Project of Henan Natural Science Foundation(No.232300420034)the National Natural Science Foundation of China for the Youth(No.81600555)the General Project of China Postdoctoral Science Foundation(No.2018M640684)。
文摘Objective Glucocorticoid(GC)-induced adverse reactions(ARs)have been extensively studied due to their potential impact on patients’health.This study aimed to examine the potential correlation between two polymorphisms[adenosine triphosphate-binding cassette B1(ABCB1)C3435T and plasminogen activator inhibitor-1(PAI-1)4G/5G]and various GC-induced ARs in nephrotic syndrome(NS)patients.Methods In this study,513 NS patients who underwent GC treatment were enrolled.Then,the patients were divided into two groups based on ABCB1 C3435T and PAI-14G/5G genotyping,and intergroup comparisons of clinicopathological data and GC-induced ARs were performed.Univariate and multivariate logistic analyses were subsequently conducted to identify potential risk factors for GC-induced ARs,and a nomogram was subsequently established and validated via the area under the ROC curve(AUC),calibration curve and decision curve analysis(DCA).Results We identified ABCB1 C3435T as an independent risk factor for the development of steroid-associated avascular necrosis of the femoral head(SANFH)(OR:2.191,95%CI:1.258–3.813,P=0.006)but not as a risk factor for the occurrence of steroid diabetes mellitus(S-DM).On the other hand,PAI-14G/5G was identified as an independent risk factor for the development of both SANFH(OR:2.198,95%CI:1.267–3.812,P=0.005)and S-DM(OR:2.080,95%CI:1.166–3.711,P=0.013).Notably,no significant correlation was found between the two gene polymorphisms and other GC-induced ARs.In addition,two nomograms were established and validated to demonstrate strong calibration capability and clinical utility.Conclusion Assessing ABCB1 C3435T and PAI-14G/5G before steroid treatment in NS patients could be useful for identifying patients at a high risk of developing SANFH and S-DM.
基金supported by the Research Fund from Ministry of Health of the People’s Republic of China, WKJ2007‐2‐024
文摘Objective To investigate the characteristic of integrons and the relationship between integrons and antimicrobial resistance in Shigella spp. Methods Ninety Shigella strains （83 S. flexneri and 7 S. sonnei） were isolated from the stools of patients in China. Susceptibility to 8 antimicrobials was tested for all isolated strains. PCR, RFLP and sequencing analysis of integrons were applied to all of them. Results High prevalence of multi‐drug resistance （95.6%） was identified. Of the isolates 79 （87.8%） carried integrase genes of class 1 integron （3.3%）, class 2 integron （10.0%） or both （74.4%）. No intI3 was detected in the tested isolates. The prevalence of intI2 was significantly higher in isolates with multi‐drug resistance to at least 3 antibiotics than that in isolates with resistance to 2 and less antibiotics （P0.05）. Gene cassettes dfrA17‐aadA5, dfrA12‐orfF‐aadA2 of class 1 integron and dfrA1‐sat1‐aadA1 of class 2 integron were identified. Conclusion The class 2 integron may play a role in the emergence of multi‐drug resistance in Shigella spp.
基金Supported by National Natural Science Foundation of China(31201949,31172362)~~
文摘[Objective] This study aimed to investigate the multidrug resistance and prevalence of class I integrons in Salmonel a. [Method] Salmonel a strains were isolated from chicken farms in Shandong Province. Kauffmann-White classification method was employed to analyze the serotypes of Salmonel a strains. Minimum in-hibition concentration （MIC） of Salmonel a strains against 19 common antimicrobial drugs was analyzed determined with microdilution method. The class I integrons and carried drug resistance gene cassettes were detected by PCR. [Result] A total of 311 Salmonel a strains were isolated and classified into two serotypes, including 133 Salmonel a Indiana strains and 178 Salmonel a Enteritidis strains. Drug sensitivity test showed that the isolated Salmonel a strains were general y resistant to sulfadiazine, sulfamethoxazole, nalidixic acid, ampicil in, tetracycline, doxycycline and trimethoprim, with a multidrug resistance rate of 91.0% （283/311）; 99% strains were sensitive to amikacin and colistin. PCR assay indicated that the detection rate of class I integrons was 65.0% （202/311）; the positive rate of class I integrons in Salmonel a strains with multidrug resistance was 92.6%; among 202 positive strains, six strains carried gene cassette dfr17-aadA5. [Conclusion] According to the above results, class I integrons exist general y in Salmonel a and are closely associated with the multidrug resistance of Salmonel a strains.
文摘Objective： MGMT protein expression has been associated with tumor resistance to alkylating agents. The objective of this paper is to construct the RNA interference vector which can specifically induce the expression silence of human DNA repair gene hMGMT. Methods： The hMGMT specific siRNA expression cassette was made by two steps PCR, linked with pUCI 9 to get pU6-MGMTi, co-transfected with pEGFP-CI into 16HBE and screened by G418. The MGMT mRNA and protein levels were detected by RT-PCR and Western Blot respectively. Results： hMGMT specific RNA interfere vector pU6-MGMTi was constructed successfully. In transfected 16HBE cells MGMT mRNA level could hardly be detected and the protein level was only 10% of control. Conclusion： MGMT specific RNAi expression cassette can effectively inhibit MGMT expression. MGMT silence cell line was built by co-transfection technology, which offered condition for studying the gene function of MGMT.
基金This work was supported by the National Natural Science Foundation of China (No. 30300221 and No. 30370132).
文摘Particle bombardment transformation using minimal gene cassette （containing the promoter, open reading frame and terminator） is the novel trend in plant genetic transformation, and its use helps to alleviate the undesirable effects of plasmid vector backbone sequences on transgenic plants. In the present article, studies related to the hereditary behavior of bar gene cassette in T1 to T3 generations of the transgenic rice （Oryza sativa L.） lines transformed by particle bombardment have been discussed. The selectable marker bar gene cassette that integrated with the rice genome had multiple copies and showed complex segregation behaviors including the presence of ‘false homozygotes’, with abnormal segregation ratios ranging from 35：1 to 144：1 （Basta-resistant： sensitive plants） in their progenies. In five out of ten original transgenic lines, bar gene can be stably transmitted as a dominant gene to self-pollinated T2 progeny. The homozygotes were obtained in three transgenic lines in T1 generation regardless of the multiple-copy integration patterns of bar gene. Southern blotting analysis showed that multiple copies of bar gene cassette were linked, which formed transgene arrays in the host rice genome. The authors also observed stable transmission of integration patterns of bar gene cassette, as obtained from Southern blotting analysis, in the regularly segregated transgenic rice lines and loss of gene in an irregularly segregated transgenic line. The segregation behavior varied among the transgenic progenies that exhibited similar Southern hybridization patterns of bar gene. On the basis of these results, the multiple-copy integration, gene lost, and gene expres- sion interaction were the major reasons for the complex segregation behaviors of bar gene cassette in transgenic rice plants.
文摘Drug resistance develops in nearly all patients with colon cancer, leading to a decrease in the therapeutic efficacies of anticancer agents. This review provides an up-to-date summary on over-expression of ATPbinding cassette(ABC) transporters and evasion of apoptosis, two representatives of transport-based and non-transport-based mechanisms of drug resistance, as well as their therapeutic strategies. Different ABC transporters were found to be up-regulated in colon cancer, which can facilitate the efflux of anticancer drugs out of cancer cells and decrease their therapeutic effects. Inhibition of ABC transporters by suppressing their protein expressions or co-administration of modulators has been proven as an effective approach to sensitize drug-resistant cancer cells to anticancer drugs in vitro. On the other hand, evasion of apoptosis observed in drug-resistant cancers also results in drug resistance to anticancer agents, especially to apoptosis inducers. Restoration of apoptotic signals by BH3 mimetics or epidermal growth factor receptor inhibitors and inhibition of cancer cell growth by alternative cell death pathways, such as autophagy, are effective means to treat such resistant cancer types. Given that the drug resistance mechanisms are different among colon cancer patients and may change even in a single patient at different stages, personalized and specific combination therapy is proposed to be more effective and safer for the reversal of drug resistance in clinics.
文摘AIM: We shall construct the small interfering RNA (siRNA) expression cassette (SEC) targeting activated K-ras gene sequence, identify more effective siRNA sequence against K-ras gene in human pancreatic cancer cell line MiaPaCa-2 by SEC and reveal the anti-cancer effects of RNA interference (RNAi) and its therapeutic possibilities. METHODS: Three different sites of SECs were constructed by PCR. K1/siRNA,K2/siRNA and K3/siRNA are located at sites 194,491 and 327, respectively. They were transfected into MiaPaCa-2 cells by liposome to inhibit the expression of activated K-ras. In the interfering groups of sites 194 and 491, we detected the apoptosis in cells by FACS after they were incubated for 48 h, then we tested the alternation of K-ras gene in MiaPaCa-2 cells by RT-PCR immunofluorescence, respectively. RESULTS: Introduction of the Kl/siRNA and K2/siRNA against K-ras into MiaPaCa-2 cells leads to increased apoptosis, and the number of apoptotic cells is increased compared with control cells. The tests of RT-PCR immunofluorescence show the effects of inhibiting expression of activated K-ras gene by RNA interference in the Kl/siRNA and K2/siRNA groups. We also find that the introduction of K3/siRNA has no effect on MiaPaCa-2 cells. CONCLUSION: Kl/siRNA and K2/siRNA can inhibit the expression of activated K-ras but K3/siRNA has no effect, demonstrating that Kl/siRNA and K2/siRNA are effective sequences against K-ras gene and K3/siRNA are not. We conclude that specific siRNA against K-ras expression may be a powerful tool to be used therapeutically against human pancreatic cancer.
文摘Various previous studies have found a negative cor-relation between the risk of cardiovascular events and serum high-density lipoprotein(HDL) cholesterol levels. The reverse cholesterol transport, a pathway of choles-terol from peripheral tissue to liver which has several potent antiatherogenic properties. For instance, the particles of HDL mediate to transport cholesterol from cells in arterial tissues, particularly from atherosclerotic plaques, to the liver. Both ATP-binding cassette trans-porters(ABC) A1 and ABCG1 are membrane cholesterol transporters and have been implicated in mediating cholesterol effluxes from cells in the presence of HDL and apolipoprotein A-I, a major protein constituent of HDL. Previous studies demonstrated that ABCA1 and ABCG1 or the interaction between ABCA1 and ABCG1 exerted antiatherosclerotic effects. As a therapeutic approach for increasing HDL cholesterol levels, much focus has been placed on increasing HDL cholesterol levels as well as enhancing HDL biochemical functions. HDL therapies that use injections of reconstituted HDL, apoA-I mimetics, or full-length apoA-I have shown dramatic effectiveness. In particular, a novel apoA-I mi-metic peptide, Fukuoka University ApoA-I Mimetic Pep-tide, effectively removes cholesterol via specific ABCA1 and other transporters, such as ABCG1, and has an an-tiatherosclerotic effect by enhancing the biological func-tions of HDL without changing circulating HDL choles-terol levels. Thus, HDL-targeting therapy has significant atheroprotective potential, as it uses lipid transporter-targeting agents, and may prove to be a therapeutic tool for atherosclerotic cardiovascular diseases.
