Studies on the temporal,structural,and interacting features of the clubroot resistance gene Rcr1 using CRISPR/Cas9-based systems

Clubroot disease is a severe threat to Brassica crops globally,particularly in western Canada.Genetic resistance,achieved through pyramiding clubroot resistance(CR)genes with different modes of action,is the most important strategy for managing the disease.However,studies on the CR gene functions are quite limited.In this study,we have conducted investigations into the temporal,structural,and interacting features of a newly cloned CR gene,Rcr1,using CRISPR/Cas9 technology.For temporal functionality,we developed a novel CRISPR/Cas9-based binary vector,pHHIGR-Hsp18.2,to deliver Rcr1 into a susceptible canola line(DH12075)and observed that early expression of Rcr1 is critical for conferring resistance.For structural functionality,several independent mutations in specific domains of Rcr1 resulted in loss-offunction,highlighting their importance for CR phenotype.In the study of the interacting features of Rcr1,a cysteine protease gene and its homologous allele in canola were successfully disrupted via CRISPR/Cas9 as an interacting component with Rcr1 protein,resulting in the conversion from clubroot resistant to susceptible in plants carrying intact Rcr1.These results indicated an indispensable role of these two cysteine proteases in Rcr1-mediated resistance response.This study,the first of its kind,provides valuable insights into the functionality of Rcr1.Further,the new vector p HHIGR-Hsp18.2 demonstrated an inducible feature on the removal of add-on traits,which should be useful for functional genomics and other similar research in brassica crops.

Genomic location of Gb1, a unique gene conferring wheat resistance to greenbug biotype F

Greenbug(Schizaphis graminum, Rondani) is a serious insect pest in many wheat growing regions and has been infesting cereal crops in the USA for over a century. Continuous occurrence of new greenbug biotypes makes it essential to explore all greenbug resistant sources available to manage this pest. Gb1, a recessive greenbug resistance gene in DS28A, confers resistance to several economically important greenbug biotypes and is the only gene found to be resistant to greenbug biotype F. A set of 174 F_(2:3)lines from the cross DS28A × Custer was evaluated for resistance to greenbug biotype F in 2020 and 2022. Selective genotyping of the corresponding F_(2) population using single nucleotide polymorphism(SNP) markers generated by genotyping-by-sequencing(GBS) led to the identification of a candidate genomic region for Gb1. Thus, SSR markers previously mapped in this region were used to genotype the entire F2population,and kompetitive allele specific PCR(KASP) markers were also developed from SNPs in the target region.Gb1 was placed in the terminal region of the short arm of chromosome 1A, and its location was confirmed in a second population derived from the cross DS28A × PI 697274. The combined data analysis from the two mapping populations delimited Gb1 to a < 1 Mb interval between 13,328,200 and 14,241,426 bp on1AS.

High-resolution genetic mapping and identification of candidate genes for the wheat stem rust resistance gene Sr8155B1

Stem rust,caused by Puccinia graminis f.sp.tritici(Pgt),threatens global wheat production.Development of cultivars with increased resistance to stem rust by identification,mapping,and deployment of resistance genes is the best strategy for controlling the disease.In this study,we performed fine mapping and characterization of the all-stage stem rust resistance(Sr)gene Sr8155B1 from the durum wheat line 8155-B1.In seedling tests of biparental populations,Sr8155B1 was effective against six Chinese Pgt races tested.In a segregating population of 5060 gametes,Sr8155B1 was mapped to a 0.06-cM region flanked by markers Pku2772 and Pku43365,corresponding to 1.5-and 2.7-Mb regions in the Svevo and Chinese Spring reference genomes.Both regions include several typical nucleotide-binding leucine-rich repeat(NLR)and protein kinase genes that represent candidate genes.Among them,three NLR genes and three receptor-like protein kinases were highly polymorphic between the parental lines and their transcripts were upregulated in the homozygous resistant line TdR2 relative to its susceptible sister line TdS4.Four markers(Pku2772,Pku43365,Pku2950,and Pku3721)developed in this study,together with seedling resistance responses,correctly predicted Sr8155B1 absence or presence in 78 tetraploid wheat genotypes tested.The presence of Sr8155B1 in tetraploid wheat accessions CItr 14916,PI 197492,and PI 197493 was confirmed by mapping in three F_(2)populations.The genetic map and linked markers developed in this study may accelerate the deployment of Sr8155B1-mediated resistance in wheat breeding programs.

Reversing multidrug resistance by RNA interference through the suppression of MDR1 gene in human hepatoma cells

AIM： To reverse the multidrug resistance （MDR） by RNA interference （RNAi）-mediated MDRI suppression in heparoma cells.METHODS： For reversing MDR by RNAi technology, two different short hairpin RNAs （shRNAs） were designed and constructed into pGenSil-1 plasmid, respectively. They were then transfected into a highly adriarnycin-resistant HepG2 hepatorna cell line （HepG2/ADM）. The RNAi effect on MDR was evaluated by real-time PCR, cell cytotoxicity assay and rhodarnine 123 （Rh123） efflux assy. RESULTS： The stably-transfected clones showed various degrees of reversal of MDR phenotype. Surprisingly, the MDR phenotype was completely reversed in two transfected clones. CONCLUSION： MDR can be reversed by the shRNAmediated MDRI suppression in HepG2/ADM cells, which provides a valuable clue to make multidrug-resistant hepatoma cells sensitive to anti-cancer drugs.

SCN1A rs6732655A/T polymorphism:Diagnostic and therapeutic insights for drug-resistant epilepsy

BACKGROUND A significant subset of individuals with epilepsy fails to respond to currently available antiepileptic drugs,resulting in heightened mortality rates,psychosocial challenges,and a diminished quality of life.Genetic factors,particularly within the SCN1A gene,and the pro-inflammatory cytokine response is important in intricating the drug resistance in idiopathic epilepsy cases.In this extended study,we determined the correlation of rs6732655A/T single nucleotide polymorphism to understand the causative association of SCN1A gene with epilepsy drug resistance and inflammatory response.AIM To find the correlation of SCN1A gene rs6732655A/T polymorphism with the drug-resistant epilepsy and inflammatory response.METHODS The study enrolled 100 age and sex-matched patients of both drug-resistant and drug-responsive epilepsy cases.We analysed the rs6732655A/T polymorphism to study its association and causative role in drug-resistant epilepsy cases using restriction fragment length polymorphism technique.The diagnostic performance of interleukin(IL)-1β,IL-6,and high mobility group box 1(HMGB1)protein levels was evaluated in conjunction with genotypic outcome receiver operating characteristic analysis.RESULTS AT and AA genotypes of rs6732655 SCN1A gene polymorphism were associated with higher risk of drug resistance epilepsy.Serum biomarkers IL-6,IL1βand HMGB1 demonstrated diagnostic potential,with cutoff values of 4.63 pg/mL,59.52 pg/mL and 7.99 ng/mL,respectively,offering valuable tools for epilepsy management.Moreover,specific genotypes(AA and AT)were found to be linked to the elevated levels of IL-1βand IL-6 and potentially reflecting increased oxidative stress and neuro-inflammation in drug-resistant cases supporting the previous reported outcome of high inflammatory markers response in drug resistance epilepsy.CONCLUSION SCN1A genotypes AA and AT are linked to higher drug-resistant epilepsy risk.These findings underscore the potential influence of inflammation and genetics on epilepsy treatment resistance.

Chitosan/pshRNA Plasmid Nanoparticles Targeting MDR1 Gene Reverse Paclitaxel Resistance in Ovarian Cancer Cells

In order to investigate the effect of chitosan/pshRNA plasmid nanoparticles targeting MDR1 genes on the resistance of A2780/TS cells to paclitaxel, chitosan/pshRNA plasmid nanoparti- cles were synthesized by means of a complex coacervation technique and transfected into A2780/TS cells. The cells transfected with MDRl-targeted chitosan/pshRNA plasmid nanoparticles were experimental cells and the cells transfected with chitosan/pGPU6/GFP/Neo no-load plasmid nanoparticles served as negative control cells. Morphological features of the nanoparticles were observed under transmission electron microscope （TEM）. MDR1 mRNA expression was assessed by RT-PCR. Half-inhibitory concentration （IC50） ofpaclitaxel for A2780/TS cells was determined by MTT method. TEM showed that the nanoparticles were round-shaped, smooth in surface and the diameters varied from 80 to 120 nm. The MDR1 mRNA in the transfected cells was significantly decreased by 17.6%, 27.8% and 52.6% on the post-transfection day 2, 4 and 7 when compared with that in A2780/TS cells control （P〈0.05）. MTT assay revealed that the relative reversal efficiency was increased over time and was 29.6%, 51.2% and 61.3% respectively in the transfected cells 2, 4, 7 days after transfection and IC_50 （0.197±0.003, 0.144±0.001, 0.120±0.004） were decreased with difference being significant when compared with that in A2780/TS （0.269±0.003） cells control （P〈0.05）. It was concluded that chitosan/pshRNA plasmid nanoparticles targeting MDR1 can effectively reverse the paclitaxel resistance in A2780/TS cells in a time-dependent manner.

Identification and Evaluation of Insect and Disease Resistance in Transgenic Cry1Ab13-1 and NPR1 Maize

PCR detection,quantitative real-time PCR(q-RTPCR),outdoor insect resistance,and disease resistance identification were carried out for the detection of genetic stability and disease resistance through generations(T2,T3,and T4)in transgenic maize germplasms(S3002 and 349)containing the bivalent genes(insect resistance gene Cry1Ab13-1 and disease resistance gene NPR1)and their corresponding wild type.Results indicated that the target genes Cry1Ab13-1 and NPR1 were successfully transferred into both germplasms through tested generations;q-PCR confirmed the expression of Cry1Ab13-1 and NPR1 genes in roots,stems,and leaves of tested maize plants.In addition,S3002 and 349 bivalent gene-transformed lines exhibited resistance to large leaf spots and corn borer in the field evaluation compared to the wild type.Our study confirmed that Cry1Ab13-1 and NPR1 bivalent genes enhanced the resistance against maize borer and large leaf spot disease and can stably inherit.These findings could be exploited for improving other cultivated maize varieties.

Effects of the Fhb1 gene on Fusarium head blight resistance and agronomic traits of winter wheat

The gene Fhb1 has been used in many countries to improve wheat Fusarium head blight(FHB) resistance. To make better use of this gene in the Yellow-Huai River Valleys Winter Wheat Zone(YHWZ), the most important wheat-producing region of China, it is desirable to elucidate its effects on FHB resistance and agronomic traits in different genetic backgrounds. Based on a diagnostic marker for Fhb1, six BC2 populations were developed by crossing dwarf-male-sterile(DMS)-Zhoumai 16 to three Fhb1 donors(Ningmai 9, Ningmai 13, and Jianyang 84) and backcrossing to Zhoumai 16 and Zhoumai16’s derivative cultivars(Lunxuan 136 and Lunxuan 13) using marker-assisted backcross breeding. The progenies were assessed for FHB resistance and major agronomic traits.The Fhb1 alleles were identified using the gene-specific molecular marker. The plants with the Fhb1-resistant genotype(Fhb1-R) in these populations showed significantly fewer infected spikelets than those with the Fhb1-susceptible genotype(Fhb1-S). When Lunxuan 136 was used as the recurrent parent, Fhb1-R plants showed significantly fewer infected spikelets per spike than Fhb1-R plants produced using Lunxuan 13 as the recurrent parent, indicating that the genetic backgrounds of Fhb1 influence the expression of FHB resistance. Fhb1-R plants from the DMS-Zhoumai 16/Ningmai 9//Zhoumai 16/3/Lunxuan 136 population showed the highest FHB resistance among the six populations and a significantly higher level of FHB resistance than the moderately susceptible control Huaimai 20. No significant phenotypic differences between Fhb1-R and Fhb1-S plants were observed for the eight agronomic traits investigated. These results suggest that it is feasible to improve FHB resistance of winter wheat withoutreducing yield potential by introgressing Fhb1 resistance allele into FHB-susceptible cultivars in the YHWZ.

Systemic acquired resistance, NPR1, and pathogenesis-related genes in wheat and barley

In Arabidopsis, systemic acquired resistance （SAR） is established beyond the initial infection by a pathogen or is directly induced by treatment with salicylic acid （SA） or its functional analogs, 2,6-dichloroisonicotinic acid （INA） and benzothiadiazole （BTH）. NPR1 protein is considered the master regulator of SAR in both SA signal sensing and transduction. In wheat （Triticum aesfivum） and barley （Hordeum vulgare）, both pathogen infection and BTH treatment can induce broad-spectrum resistance to various diseases, including powdery mildew, leaf rust, Fusarium head blight, etc. However, three different types of SAR-like responses including acquired resistance （AR）, systemic immunity （SI）, and BTH-induced resistance （BIR） seem to be achieved by activating different gene pathways. Recent research on wheat and barley NPR1 homologs in AR and SI has provided the initial clue for understanding the mechanism of SAR in these two plant species. In this review, the specific features ofAR, Si, and BIR in wheat and barley were summarized and compared with that of SAR in model plants of Arabidopsis and rice. Research updates on downstream genes of SAR, including pathogenesis-related （PR） and BTH-induced genes, were highlighted.

Association of single nucleotide polymorphisms of brain-derived neurotrophic factor gene and multidrug resistance 1 gene to refractory epilepsy in Chinese Han children

BACKGROUND： There are two hypotheses for the underlying cause of refractory epilepsy： ＂target＂ and ＂transport＂. Studies have shown that brain-derived neurotrophic factor （BDNF） is over-expressed in refractory epilepsy. Multidrug resistance 1 （MDR1） gene encodes for P-glycoprotein, the primary ATP-binding cassette transporter in the human body. Some single nucleotide polymorphisms of the MDR1 gene have been associated with refractory epilepsy. OBJECTIVE： To investigate the association between BDNF gene C270T polymorphism and MDR1 T-129C polymorphism with refractory epilepsy in Chinese Han children through the use of polymerase chain reaction （PCR）-restriction fragment length polymorphism analysis. DESIGN, TIME AND SETTING： A case-control, genetic association study was performed at the Central Laboratory, Third Xiangya Hospital of Central South University from June 2005 to November 2007. PARTICIPANTS： A total of 84 cases of unrelated children with epilepsy, including 41 cases of refractory epilepsy and 43 cases of drug-responsive epilepsy, were enrolled. An additional 30 healthy, Chinese Han children, whose ages and gender matched the refractory epilepsy patients, were selected as normal controls. METHODS： Venous blood was collected and genomic DNA was extracted from the blood specimens. C270T polymorphism in BDNF gene and T-129C polymorphism in MDR1 gene were genotyped using PCR-restriction fragment length polymorphism analysis. Association analysis using the Ftest and Chi-square test was statistically performed between C270T polymorphism in BDNF gene and T-129C polymorphism in MDR1 gene and refractory epilepsy. MAIN OUTCOME MEASURES： The distribution of genotypes and allele frequencies of C270T polymorphism in BDNF gene and T-129C polymorphism in MDR1 gene. RESULTS： The distribution of CC, CT, and TT genotypes, as well as C and T allele frequencies, in the BDNF gene was not significantly different between the refractory epilepsy group, drug-responsive epilepsy group, or the normal control group （P 〉 0.05）. The distribution of TT genotype and T allele frequencies of the MDR1 gene was significantly different in the refractory epilepsy group compared with the drug-responsive epilepsy and normal control groups （P 〈 0.05）. Comparison of haplotype combinations demonstrated that there were no significant differences in combinations of TT＋CC, -FI-＋CT, TC＋CC, and TC＋CT among the three groups （P 〉 0.05）. CONCLUSION： C270T polymorphism of the BDNF gene was not associated with refractory epilepsy in Chinese Han children, but T-129C polymorphism in the MDR1 gene was associated with refractory epilepsy in Chinese Han children. The TT genotype and T allele frequencies could serve as susceptibility loci for refractory epilepsy. Interactions between C270T in BDNF gene and T-129C in MDR1 gene were not observed in refractory epilepsy in Chinese Han children.

Breeding of Selectable Marker-Free Transgenic Rice Lines Containing AP1 Gene with Enhanced Disease Resistance

In order to obtain marker-free transgenic rice with improved disease resistance, the AP1 gene of Capsicum annuum and hygromycin-resistance gene （HPT） were cloned into the two separate T-DNA regions of the binary vector pSB130, respectively, and introduced into the calli derived from the immature seeds of two elite japonica rice varieties, Guangling Xiangjing and Wuxiangjing 9, mediated by Agrobacterium-mediated transformation. Many cotransgenic rice lines containing both the AP1 gene and the marker gene were regenerated and the integration of both transgenes in the transgenic rice plants was confirmed by either PCR or Southern blotting technique. Several selectable marker-free transgenic rice plants were subsequently obtained from the progeny of the cotransformants, and confirmed by both PCR and Southern blotting analysis. These transgenic rice lines were tested in the field and their resistance to disease was carefully investigated, the results showed that after inoculation the resistance to either bacterial blight or sheath blight of the selected transgenic lines was improved when compared with those of wild type.

Expression of multidrug resistance 1 gene and C3435T genetic polymorphism in peripheral blood of patients with intractable epilepsy

BACKGROUND： Increased expression of multidrug resistance 1 （MDR1） mRNA in peripheral blood of patients with intractable epilepsy is not due to epilepsy drugs, but epilepsy behavior. Monitoring MDR1 expression in peripheral blood is a target for MDR1 gene evaluation. OBJECTIVE： To investigate the influence of antiepileptic drugs and seizures on MDR expression in intractable epilepsy, and to analyze the genetic polymorphisms of C3435T in the MDRl gene. DESIGN, TIME AND SETTING： Factorial designs and comparative observations at the experimental center of the Affiliated Hospital of Qingdao Medical College, Qingdao University between October 2003 and October 2004. PARTICIPANTS： A total of 120 subjects were recruited from the epilepsy clinical department of the Affiliated Hospital of Qingdao Medical College. Four groups （n = 30） were classified according to statistical factorial design： intractable epilepsy, treatment response, no treatment, and normal control groups. METHODS： One-step semi-quantitative reverse-transcription polymerase chain reaction technology was used to test expressions of the MDR1 gene in 120 subjects. C3435T polymorphisms in intractable epilepsy group and normal control groups were analyzed by polymerase chain reaction-restriction fragment length polymorphism. MAIN OUTCOME MEASURES： Expression of MDR1 mRNA in the four groups, and C3435T genetic polymorphisms in intractable epilepsy and normal control groups. RESULTS： MDRl gene expression was increased in the intractable epilepsy group, due to the factor seizures, but not the antiepileptic drugs. However, the interaction between the two factors was not statistically significant. Of the 30 subjects in the intractable epilepsy group, the following genotypes were exhibited： 3 （10%） C/C genotype, 9 （30%） C/T genotype, and 18 （60%） T/T genotype at the site of C3435T, while 4 （13%）, 10 （33%）, and 16 （53%） subjects were determined to express these genotypes in the normal control group, respectively. C and T allele frequency were 25% and 75% in the intractable epilepsy group, and 30% and 70% in the normal control group, respectively. However, there was no statistical difference between the groups. CONCLUSION： Results demonstrated that seizures, not antiepileptic drugs, induced MDR1 gene expression in intractable epilepsy. Genetic polymorphisms of C3435T in the MDR1 gene did not contribute to the development of multidrug resistance in patients with intractable epilepsy.

Bioinformatics Analysis of Disease Resistance Gene PR1 and Its Genetic Transformation in Soybeans and Cultivation of Multi-resistant Materials

In agricultural production,a single insect-resistant and disease-resistant variety can no longer meet the demand.In this study,the expression vector pCAMBIA-3301-PR1 containing the disease-resistant gene PR1 was constructed by means of genetic engineering,and the PR1 gene was genetically transformed to contain the PR1 gene through the pollen tube method.In CryAb-8Like transgenic high-generation T7 receptor soybean,a new material that is resistant to insects and diseases is obtained.For T2 transformed plants,routine PCR detection,Southern Blot hybridization,fluorescence quantitative PCR detection,indoor and outdoor pest resistance identification and indoor disease resistance identification were performed.The results showed that there were 9 positive plants in the routine PCR test of T2 generation.In Southern Blot hybridization,both PR1 and CryAb-8Like genes are integrated in soybeans in the form of single copies.Fluorescence quantitative PCR showed that the expression levels of PR1 and CryAb-8Like genes are different in different tissues.The average expression levels of PR1 gene in plant roots,stems,and leaves are 2.88,1.54,and 5.26,respectively.CryAb-8Like genes are found in roots,stems,and leaves.The average expression levels were 1.36,1.39,and 4.25,respectively.The insectivorous rate of the CryAb-8Like gene in outdoor plants with positive insect resistance identification was 3.78%.The disc partition method was used indoors for pest resistance identification,and the bud length of transformed plants increased significantly.The average mortality rate of untransformed plants in indoor disease resistance identification was as high as 56.66%,and the average mortality rate of plants transformed with PR1 gene was 10.00%,and disease resistance was significantly improved.Therefore,a new material with resistance to diseases and insects is obtained.

Analysis of drought resistance HVA1 gene under drought stress in different Poa pratensis cultivars

Total RNA from leaves of Poapratensis cultivars under drought stress was extracted for reversing transcription to cDNA and then cDNA as template for PCR reaction by designing primer of cds of Hordeum valgare HVA1 drought resistance gene from GenBank. The amplified products were positive recon identified by using procedures of recovery, connection, transformation and enzyme separation. The length of cloned gene sequence was 324 bp, identity reached 79.27% with Barley HVA1 gene that meaned the cloned gene sequence was the partial HVA1 gene of Poapratensis.

Development of Hybrid Rice Variety FY7206 with Blast Resistance Gene Pid3 and Cold Tolerance Gene Ctb1

Hybrid rice Fanyou 7206（FY7206）, derived from the cross between a sterile line Fanyuan A and a restorer line Fuhui 7206, was bred by the Rice Research Institute, Fujian Academy of Agricultural Sciences, China. FY7206 was characterized by moderate blast resistance, cold tolerance, as well as wide adaptability, and high yields. The blast resistance results indicated that the frequencies of blast races in race B, race C and the total resistance frequency for FY7206 were 95.5%, 100.0% and 97.2%, respectively. The disease resistance results showed that the leaf blast grade for FY7206 was level 1 and panicle blast was level 5. The indoor spray results indicated that FY7206 was resistant to 11 isolates of Magnorpathe oryzae. The blast resistance of FY7206 might be derived from the high expression of blast resistance gene Pid3. The results for simulated cold resistance in an artificial climate chamber indicated that the cold tolerance for FY7206 was moderate at the booting and flowering stages. The cold tolerance results also indicated that FY7206 could be tolerant to temperatures as low as 10 °C at the seedling stage. The q RT-PCR results showed that the expression of cold tolerance gene Ctb1 in FY7206 was relatively high. These results suggested that FY7206 is a hybrid indica rice variety with good comprehensive characteristics, including blast resistance and cold tolerance.

猕猴桃病程相关蛋白PR-1基因的克隆和功能分析

【目的】探究猕猴桃病程相关蛋白(pathogenesis-related proteins,PRs)PR-1基因在响应丁香假单胞杆菌中的功能。【方法】以毛花猕猴桃(Actinidia eriantha)为材料,克隆得到PR-1同源基因AePR-1全长序列,并对其序列进行生物信息学分析。采用实时荧光定量方法检测AePR-1基因在不同组织、花器官以及接种细菌性溃疡病菌(Psa)和不同激素(SA、ABA、GA_(3))处理条件下的表达情况。利用亚细胞定位技术分析AePR-1基因在细胞中的表达位置。通过在本氏烟草中过表达AePR-1基因,验证其在溃疡病菌响应过程中的功能。【结果】猕猴桃AePR-1基因序列全长522 bp,编码173个氨基酸,序列中含有6个保守的半胱氨酸结构基序和4个allergen V5/Tpx-1 related保守结构域。亚细胞定位发现AePR-1定位在细胞膜和细胞质中。AePR-1在猕猴桃根和雌蕊中高表达,且能够响应溃疡病菌及激素处理。过表达AePR-1的烟草在接种溃疡病菌后,叶片病斑数明显少于对照组。【结论】AePR-1基因在溃疡病菌和激素诱导下显著表达且过表达能够增强烟草对溃疡病的抗性,说明猕猴桃PR-1基因在响应生物和非生物胁迫中具有重要作用。

<i>Escherichia coli</i>Harbouring Resistance Genes, Virulence Genes and Integron 1 Isolated from Athi River in Kenya

Rivers can act as reservoirs of highly resistant strains and facilitate the dissemination of resistance, virulence and integron 1 genes. A cross-sectional study was carried out where 318 water samples were collected (53 from each site) and from the samples, 318 E. coli isolates were analysed for resistance genes, virulence genes and integron 1 using Polymerase Chain Reaction. 22% of the isolates had blaTEM, 33% had blaCTX-M and 28% had blaCMY. Prevalence of typical Enteropathogenic E. coli strains (carrying both eae and bfp genes) was 5% while the prevalence of atypical Enteropathogenic E. coli (carying only eae) was 1.8%. The prevalence of Enteroaggregative E. coli carrying the aggr genes was 11%. The prevalence of Enterotoxigenic E. coli encoding only lt toxin was 16 (5%) and while those carrying only st toxin was 6.9%. The prevalence of Enteroinvasive E. coli strains encoding as IpaH was 5% while that of strains, adherent invasive E. coli, carrying adherent invasive gene inv was 8.7%. 36% isolates were positive for class 1 integrons which were mostly isolated near the sewage effluent from waste treatment plant. Anthropogenic activities and close proximity to sewage treatment plant were found to play a key role in pollution of water body and accumulation of resistance and virulence genes. These results suggest that waste treatment plant may act as reservoir of resistance, virulence and integron 1 genes and is a potential risk to human and animal health in the region.

白介素37下调多药耐药基因-1逆转肺腺癌紫杉醇耐药的研究

目的 本研究旨在探究白介素37(IL-37)在抑制肺腺癌细胞多药耐药性方面的潜在作用,及其对于耐紫杉醇的A549/TAX细胞的影响。方法 通过细胞培养、处理程序、实时荧光定量PCR、Western blot分析和统计学分析等实验方法,系统研究了IL-37对耐紫杉醇A549/TAX细胞的影响。结果 紫杉醇明显抑制了A549和A549/TAX细胞的增殖,其中A549/TAX的耐药指数RI为16.88。100ng/mL的rhIL-37显著抑制了A549/TAX细胞的增殖。在紫杉醇和rhIL-37联合处理组,细胞增殖的抑制率显著高于仅用紫杉醇处理组(P<0.05)。此外,rhIL-37在24小时后显著抑制了A549/TAX细胞的迁移和侵袭。非细胞毒性浓度的rhIL-37也能显著抑制A549/TAX细胞的集落形成。经rhIL-37作用48小时后,A549/TAX细胞中MDR1的表达水平比对照组下降了约66%(P<0.05)。结论 IL-37与紫杉醇联合处理可有效抑制A549/TAX细胞的增殖、迁移和侵袭,同时通过降低MDR1基因的表达水平可能逆转细胞的耐药性,为IL-37在肺腺癌治疗中的潜在应用提供了实验依据。

猪场环境源大肠杆菌的耐药性调查及携带mcr-1和tet(X4)菌株的传播特征

养殖场中抗菌药的长期使用促使耐药菌株快速出现和传播,并可以通过粪肥和污水向环境排放,给公共卫生带来巨大威胁。为了调查猪场环境源大肠杆菌的耐药情况,评估耐药基因的传播风险,本试验采集163份猪场粪便、污水和土壤样本,通过平板划线分离培养法分离大肠杆菌,通过药敏试验检测分离菌株对14种抗菌药物的耐药情况,聚合酶链式反应(PCR)检测临床重要耐药基因,脉冲场凝胶电泳(PFGE)检测菌株间的亲缘关系,接合试验和质粒复制子分型检测接合子的质粒类型。结果显示,共分离获得150株大肠杆菌,其中粪便源大肠杆菌耐药情况最严重,污水源大肠杆菌次之,土壤源大肠杆菌最低;污水源大肠杆菌耐药基因检出种类最多,粪便源大肠杆菌次之,土壤源大肠杆菌最少。10株携带黏菌素耐药基因mcr-1大肠杆菌和18株携带替加环素耐药基因tet(X4)大肠杆菌分离自粪便和污水样本,且多重耐药情况较为严重。10株携带mcr-1大肠杆菌经PFGE分为9种脉冲场图谱,其中9株与大肠杆菌C600接合成功,接合子中有IncFIA、IncW、IncFIB、IncI2和IncP五种质粒类型;18株携带tet(X4)大肠杆菌经PFGE分为15种脉冲场图谱,其中16株与大肠杆菌C600接合成功,接合子中有IncFIB、IncFrepB和IncHI1三种质粒类型。结果表明,必需持续监测猪场环境中的临床重要耐药基因,特别需要关注mcr-1和tet(X4)基因的流行情况,并且在养殖中合理使用黏菌素和四环素类抗生素。

Correlation of Kif2a and HPK1 expression in breast cancer with the oncogene and drug resistance gene expression

Objective: To investigate the correlation of Kif2a and HPK1 expression in breast cancer with the oncogene and drug resistance gene expression. Methods: A total of 91 patients with breast cancer and 85 patients with breast adenoma who accepted surgical treatment in our hospital between August 2016 and February 2018 were selected, and the breast cancer tissues and breast adenoma tissues were collected respectively as the research samples. Fluorescence quantitative PCR method was used to detect the expression of Kif2a and HPK1 genes as well as oncogenes and drug resistance genes in sample tissues, and Pearson test was used to evaluate the inner link of Kif2a and HPK1 gene expression in breast cancer tissue with oncogene and drug resistance gene expression. Results: Kif2a mRNA expression in breast cancer tissues was higher than that in breast adenoma tissues whereas HPK1 mRNA expression was lower than that in breast adenoma tissues;oncogenes DEK, iASPP-SV, Stat3, MDM2 and Fra-1 mRNA expression were higher than those in breast adenoma tissues;drug resistance genes ESR1, MDR1, P-gp, MRP1 and GST- mRNA expression were higher than those in breast adenoma tissues whereas BCRP mRNA expression was lower than that in breast adenoma tissues. Correlation analysis showed that the Kif2a and HPK1 gene expression in breast cancer tissues were directly correlated with the expression of oncogenes and drug resistance genes. Conclusion: Kif2a gene is abnormally highly expressed whereas HPK1 gene is abnormally lowly expressed in breast cancer tissues, and they are involved in the regulation of oncogene and drug resistance gene expression.