scholarly journals Expression of the qepA1 gene is induced under antibiotic exposure

2021 ◽  
Author(s):  
Gerrit Brandis ◽  
Jonas Gockel ◽  
Linnéa Garoff ◽  
Lionel Guy ◽  
Diarmaid Hughes
Keyword(s):  
Gene Expression ◽  
Efflux Pump ◽  
Class I ◽  
Upstream Region ◽  
Antibiotic Exposure ◽  
Negative Effects ◽  
Integrase Gene ◽  
Bacterial Fitness ◽  
High Level

Abstract Background The qepA1 gene encodes an efflux pump that reduces susceptibility to ciprofloxacin. Little is known about the regulation of qepA1 expression. Objectives To assess the potential role of ciprofloxacin and other antibiotics in the regulation of qepA1 gene expression. To identify the promoter that drives qepA1 expression and other factors involved in expression regulation. To assess whether the identified features are universal among qepA alleles. Methods A translational qepA1-yfp fusion under the control of the qepA1 upstream region was cloned into the Escherichia coli chromosome. Expression of the fusion protein was measured in the presence of various antibiotics. Deletions within the upstream region were introduced to identify regions involved in gene expression and regulation. The qepA1 coding sequence and upstream region were compared with all available qepA sequences. Results Cellular stress caused by the presence of various antibiotics can induce qepA1 expression. The qepA1 gene is fused to a class I integron and gene expression is driven by the Pc promoter within the integrase gene. A segment within the integron belonging to a truncated dfrB4 gene is essential for the regulation of qepA1 expression. This genetic context is universal among all sequenced qepA alleles. Conclusions The fusion of the qepA1 gene to a class I integron has created a novel regulatory unit that enables qepA1 expression to be under the control of antibiotic exposure. This setup mitigates potential negative effects of QepA1 production on bacterial fitness by restricting high-level expression to environmental conditions in which QepA1 is beneficial.

scholarly journals Increased gene expression and copy number of mutated blaKPC lead to high-level ceftazidime/avibactam resistance in Klebsiella pneumoniae

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lingxiao Sun ◽  
Haibo Li ◽  
Qi Wang ◽  
Yingmei Liu ◽  
Bin Cao
Keyword(s):  
Gene Expression ◽  
Minimal Inhibitory Concentration ◽  
Copy Number ◽  
Inhibitory Concentration ◽  
Efflux Pump ◽  
Relative Gene Expression ◽  
Significant Difference ◽  
High Level ◽  
Relative Gene

Abstract Background Resistance to ceftazidime-avibactam was reported, and it is important to investigate the mechanisms of ceftazidime/avibactam resistance in K. pneumoniae with mutations in blaKPC. Results We report the mutated blaKPC is not the only mechanism related to CZA resistance, and investigate the role of outer porin defects, efflux pump, and relative gene expression and copy number of blaKPC and ompk35/36. Four ceftazidime/avibactam-sensitive isolates detected wild type blaKPC-2, while 4 ceftazidime/avibactam-resistant isolates detected mutated blaKPC (blaKPC-51, blaKPC-52, and blaKPC-33). Compared with other ceftazidime/avibactam-resistant isolates with the minimal inhibitory concentration of ceftazidime/avibactam ranging 128–256 mg/L, the relative gene expression and copy number of blaKPC was increased in the isolate which carried blaKPC-51 and also showed the highest minimal inhibitory concentration of ceftazidime/avibactam at 2048 mg/L. The truncated Ompk35 contributes rare to ceftazidime/avibactam resistance in our isolates. No significant difference in minimal inhibitory concentration of ceftazidime/avibactam was observed after the addition of PABN. Conclusions Increased gene expression and copy number of mutated blaKPC can cause high-level ceftazidime/avibactam resistance.

scholarly journals Significant contribution of the CmeABC Efflux pump in high-level resistance to ciprofloxacin and tetracycline in Campylobacter jejuni and Campylobacter coli clinical isolates

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Saeed Sharifi ◽  
Bita Bakhshi ◽  
Shahin Najar-peerayeh
Keyword(s):  
Gene Expression ◽  
Point Mutation ◽  
Campylobacter Jejuni ◽  
Significant Contribution ◽  
Efflux Pump ◽  
Campylobacter Coli ◽  
Rapd Pcr ◽  
Resistant Strains ◽  
High Level ◽  
Level Resistance

Abstract Background Campylobacter resistance to antimicrobial agents is regarded as a major concern worldwide. The aim of this study was to investigate the expression of the CmeABC efflux pump and the RAPD-PCR pattern in drug-resistant Campylobacter isolates. Methods A total of 283 stool specimens were collected from children under the age of five with diarrhea. The minimum inhibitory concentration (MIC) of tetracycline and ciprofloxacin was determined by broth microdilution method and E-test, respectively. Detection of tetracycline and ciprofloxacin determinants was done by amplification of tetO gene and PCR-sequencing of the gyrA gene. The cmeABC transcriptional expression was analyzed by Real-time (RT)-PCR. Clonal correlation of resistant strains was determined by RAPD-PCR genotyping. Results Out of 283 fecal samples, 20 (7.02%) samples were positive for Campylobacter spp. Analysis of duplex PCR assay of the cadF gene showed that 737 and 461 bp amplicons were corresponding to Campylobacter jejuni and Campylobacter coli, respectively. All of the 17 phenotypically tetracycline-resistant Campylobacter isolates harbored the tetO gene. Also, four phenotypically ciprofloxacin-resistant Campylobacter isolates had a point mutation at codon 257 of the gyrA gene (ACA to ATA; Thr > Ile). High-level expression of the cmeA gene was observed in ciprofloxacin-resistant and high-level tetracycline-resistant Campylobacter isolates, suggesting a positive correlation between the cmeA gene expression level and tetracycline resistance level. Moreover, a statistically significant difference was observed in the cmeA gene expression between ciprofloxacin-resistant and ciprofloxacin-susceptible strains, which signifies the crucial contribution of the efflux pump in conferring multiple drug resistance phenotype among Campylobacter spp. RAPD analysis of Campylobacter isolates exhibited 16 different patterns. Simpsone`s diversity index of RAPD-PCR was calculated as 0.85, showing a high level of homogeneity among the population; however, no clear correlation was detected among tetracycline and/or ciprofloxacin resistant isolates. Conclusion Significant contribution of the CmeABC efflux pump in conferring high-level resistance to tetracycline and ciprofloxacin was observed in C. jejuni and C. coli clinical isolates. The resistant phenotype is suggested to be mediated by CmeABC efflux pumps, the tetO gene, and point mutation of the gyrA gene. Genotyping revealed no clonal correlation among resistant strains, indicating distinct evolution of tetracycline and ciprofloxacin resistant genotypes among the isolates.

scholarly journals Positive Regulation of fur Gene Expression via Direct Interaction of Fur in a Pathogenic Bacterium, Vibrio vulnificus

2007 ◽  
Vol 189 (7) ◽  
pp. 2629-2636 ◽  
Author(s):  
Hyun-Jung Lee ◽  
So Hyun Bang ◽  
Kyu-Ho Lee ◽  
Soon-Jung Park
Keyword(s):  
Gene Expression ◽  
Pathogenic Bacteria ◽  
Vibrio Vulnificus ◽  
Iron Concentration ◽  
Direct Interaction ◽  
Repeated Sequence ◽  
Upstream Region ◽  
Fur Protein

ABSTRACT In pathogenic bacteria, the ability to acquire iron, which is mainly regulated by the ferric uptake regulator (Fur), is essential to maintain growth as well as its virulence. In Vibrio vulnificus, a human pathogen causing gastroenteritis and septicemia, fur gene expression is positively regulated by Fur when the iron concentration is limited (H.-J. Lee et al., J. Bacteriol. 185:5891-5896, 2003). Footprinting analysis revealed that an upstream region of the fur gene was protected by the Fur protein from DNase I under iron-depleted conditions. The protected region, from −142 to −106 relative to the transcription start site of the fur gene, contains distinct AT-rich repeats. Mutagenesis of this repeated sequence resulted in abolishment of binding by Fur. To confirm the role of this cis-acting element in Fur-mediated control of its own gene in vivo, fur expression was monitored in V. vulnificus strains using a transcriptional fusion containing the mutagenized Fur-binding site (fur mt::luxAB). Expression of fur mt::luxAB showed that it was not regulated by Fur and was not influenced by iron concentration. Therefore, this study demonstrates that V. vulnificus Fur acts as a positive regulator under iron-limited conditions by direct interaction with the fur upstream region.

scholarly journals Efflux-Related Resistance to Norfloxacin, Dyes, and Biocides in Bloodstream Isolates of Staphylococcus aureus

2007 ◽  
Vol 51 (9) ◽  
pp. 3235-3239 ◽  
Author(s):  
Carmen E. DeMarco ◽  
Laurel A. Cushing ◽  
Emmanuel Frempong-Manso ◽  
Susan M. Seo ◽  
Tinevimbo A. A. Jaravaza ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Efflux Pump ◽  
Resistance Mechanism ◽  
Efflux Pump Inhibitor ◽  
Qrt Pcr ◽  
Reverse Transcription Pcr ◽  
Environmental Surfaces ◽  
Genes Encoding ◽  
High Level

ABSTRACT Efflux is an important resistance mechanism in Staphylococcus aureus, but its frequency in patients with bacteremia is unknown. Nonreplicate bloodstream isolates were collected over an 8-month period, and MICs of four common efflux pump substrates, with and without the broad-spectrum efflux pump inhibitor reserpine, were determined (n = 232). A reserpine-associated fourfold decrease in MIC was considered indicative of efflux. Strains exhibiting efflux of at least two of the four substrates were identified (“effluxing strains” [n = 114]). For these strains, MICs with or without reserpine for an array of typical substrates and the expression of mepA, mdeA, norA, norB, norC, and qacA/B were determined using quantitative real-time reverse transcription-PCR (qRT-PCR). A fourfold or greater increase in gene expression was considered significant. The most commonly effluxed substrates were ethidium bromide and chlorhexidine (100 and 96% of effluxing strains, respectively). qRT-PCR identified strains overexpressing mepA (5 [4.4%]), mdeA (13 [11.4%]), norA (26 [22.8%]), norB (29 [25.4%]), and norC (19 [16.7%]); 23 strains overexpressed two or more genes. Mutations probably associated with increased gene expression included a MepR-inactivating substitution and norA promoter region insertions or deletions. Mutations possibly associated with increased expression of the other analyzed genes were also observed. Effluxing strains comprised 49% of all strains studied (114/232 strains), with nearly half of these overexpressing genes encoding MepA, MdeA, and/or NorABC (54/114 strains). Reduced susceptibility to biocides may contribute to persistence on environmental surfaces, and efflux of drugs such as fluoroquinolones may predispose strains to high-level target-based resistance.

Proteinase-activated receptors in ovine cervical function

2005 ◽  
Vol 17 (7) ◽  
pp. 693 ◽  
Author(s):  
Sharon E. Mitchell ◽  
John J. Robinson ◽  
Margaret E. King ◽  
Lynda M. Williams
Keyword(s):  
Gene Expression ◽  
In Situ Hybridisation ◽  
Prostaglandin F2α ◽  
Cervical Dilation ◽  
Proteinase Activated Receptors ◽  
Pregnant Ewe ◽  
High Level ◽  
And Function

In sheep, inflammation not only functions in cervical dilation at parturition, but also plays an important part in the non-pregnant ewe cervix, as demonstrated by the high level of expression of interleukin (IL)-8 at oestrus. Ewes artificially induced to ovulate have significantly lower levels of IL-8 gene expression at oestrus compared with natural oestrus, indicating an inhibition of inflammation and function, offering an explanation for the low rates of conception in vaginally inseminated synchronised ewes. To identify potential pro-inflammatory agents to combat the anti-inflammatory effects of hormonal synchronisation of oestrus, we have investigated the role of proteinase-activated receptor (PAR)-1 and PAR-2. To localise and measure the level of expression of these receptors, ovine-specific probes were derived for PAR-1 and PAR-2 and used for quantitative in situ hybridisation in the ovine cervix. Both PAR-1 and PAR-2 were expressed in the luminal epithelium of the cervix throughout the oestrous cycle, with expression being highest at oestrus. The gene expression of PAR-2 at oestrus was approximately 30% higher than that of PAR-1. Artificial synchronisation of oestrus by either an intravaginal progesterone sponge or prostaglandin F2α injections did not inhibit PAR-1 or PAR-2 expression at oestrus; rather, in the case of PAR-2, progesterone synchronisation increased it. Both synchronising procedures increased the expression of PAR-1 and PAR-2 during the luteal phase of the cycle. Therefore, agonists of PAR-1 and PAR-2 may be potentially useful pro-inflammatory agents countering the inhibition of inflammation by hormonal synchronisation.

scholarly journals Role of upstream DNase I hypersensitive sites in the regulation of human alpha globin gene expression

Blood ◽  
1993 ◽  
Vol 82 (5) ◽  
pp. 1666-1671
Author(s):  
JA Sharpe ◽  
RJ Summerhill ◽  
P Vyas ◽  
G Gourdon ◽  
DR Higgs ◽  
...  
Keyword(s):  
Gene Expression ◽  
Globin Gene ◽  
Single Copy ◽  
Beta Globin ◽  
Hypersensitive Sites ◽  
Alpha Globin ◽  
Alpha Gene ◽  
High Level ◽  
Globin Gene Expression

Erythroid-specific DNase 1 hypersensitive sites have been identified at the promoters of the human alpha-like genes and within the region from 4 to 40 kb upstream of the gene cluster. One of these sites, HS-40, has been shown previously to be the major regulator of tissue-specific alpha-globin gene expression. We have now examined the function of other hypersensitive sites by studying the expression in mouse erythroleukemia (MEL) cells of various fragments containing these sites attached to HS-40 and an alpha-globin gene. High level expression of the alpha gene was observed in all cases. When clones of MEL cells bearing a single copy of the alpha-globin gene fragments were examined, expression levels were similar to those of the endogenous mouse alpha genes and similar to MEL cells bearing beta gene constructs under the control of the beta-globin locus control region. However, there was no evidence that the additional hypersensitive sites increased the level of expression or conferred copy number dependence on the expression of a linked alpha gene in MEL cells.

scholarly journals The role of miR-92b in cholangiocarcinoma patients

2018 ◽  
Vol 33 (3) ◽  
pp. 293-300 ◽  
Author(s):  
Min-hang Zhou ◽  
Hong-wei Zhou ◽  
Mo Liu ◽  
Jun-zhong Sun
Keyword(s):  
Gene Expression ◽  
Overall Survival ◽  
Gene Expression Omnibus ◽  
Cancer Genome ◽  
The Cancer Genome Atlas ◽  
Positive Regulation ◽  
Cancer Genome Atlas ◽  
High Level ◽  
Genome Atlas

Purpose: The role of microRNA (miRNA) in cholangiocarcinoma was not clear. The aim of this study was to find the potential diagnostic and prognostic miRNA in cholangiocarcinoma patients. Methods: The miRNA expression profiles in cholangiocarcinoma patients from The Cancer Genome Atlas and Gene Expression Omnibus (GSE53870) were analyzed. The comparison of overall survival was performed using the Kaplan–Meier method. The targeted genes of prognostic miRNA were identified in miRanda, PicTar, or TargetScan, and their cell signaling pathways were analyzed by the Database for Annotation, Visualization and Integrated Discovery. Results: In The Cancer Genome Atlas and the Gene Expression Omnibus miRNA dataset, miR-92b and miR-99a were found with concordant directionality, up-regulated and down-regulated, respectively. In The Cancer Genome Atlas survival data, patients with the high level of miR-99b had obviously shorter overall survival time ( P=0.038). However, the level of miR-99a was not found to be significant. The 17 shared target genes of miR-92b were identified, such as DAB21IP, BCL21L11, SPHK2, PER2, and TSC1. The related pathways included positive regulation of transcription, positive regulation of cellular biosynthetic process, regulation of programmed cell death, etc. Conclusion: miR-92b was up-regulated in cholangiocarcinoma compared with normal controls. The high level of miR-92b was associated with adverse outcomes in cholangiocarcinoma patients, which might be partly explained by the targeted genes of miR-92b and their signaling pathways.

scholarly journals Creating Biotechnological Hybrids of Sugar Beet

2019 ◽  
Vol 8 (6) ◽  
pp. 5167-5175 ◽  
Keyword(s):  
Gene Expression ◽  
Sugar Beet ◽  
Target Genes ◽  
Mendelian Segregation ◽  
Breeding Programs ◽  
Its Gene ◽  
Pair Mating ◽  
The Stability ◽  
High Level

Currently, implementation of the breeding programs, including the commonly recognized areas and classic breeding methods, cannot sufficiently ensure a quick and significant increase in the productivity of sugar beet hybrids, since its gene pool is almost exhausted. Based on the achievements in the field of genetics, new approaches to and opportunities in creating highly productive agrocoenoses of sugar beet have become popular. As a result of many years of work, results have been obtained about the nature of inheriting the resistance to glyphosate in individual heterozygous apo- and syncarpous forms in case of inbreeding and pair mating with the MC tester. The expression of target genes in the generations was monitored by the survival rate of sugar beet plants after the treatment with glyphosate. During the research, individuals with a high level of gene expression were selected. Upon self-pollination of initial heterozygous original forms, deviations from Mendelian segregation were observed in most cases. The criterion for assessing the stability of expression of glyphosate resistance genes in case of seed breeding was the compliance with the laws of Mendel among the analyzed descendants. In the initial stages of the research, the level of stability gene expression had been 10 – 15 % of the total number of analyzed plants. After four self-pollinations, the stability gene expression significantly increased, and genotypes with the resistance of 91 – 100 % were selected. The first apo- and syncarpous self-pollinating lines of sugar beet with high tolerance in the role of resistance donors have been created. The positive results of preliminary tests of the first glyphosate-tolerant hybrids need confirmation. Seeds and roots of resistant forms have been obtained for further research.

An upstream element of the TamS1 gene is a site of DNA-protein interactions during differentiation to the merozoite in Theileria annulata

2000 ◽  
Vol 113 (12) ◽  
pp. 2243-2252 ◽  
Author(s):  
B. Shiels ◽  
M. Fox ◽  
S. McKellar ◽  
J. Kinnaird ◽  
D. Swan
Keyword(s):  
Gene Expression ◽  
Protein Interactions ◽  
Theileria Annulata ◽  
Upstream Region ◽  
Fundamental Aspect ◽  
Transcriptional Level ◽  
Mobility Shift ◽  
Nuclear Extracts ◽  
Mobility Shift Assay ◽  
High Level

Apicomplexan parasites are major pathogens of humans and domesticated animals. A fundamental aspect of apicomplexan biology, which may provide novel molecular targets for parasite control, is the regulation of stage differentiation. Studies carried out on Theileria annulata, a bovine apicomplexan parasite, have provided evidence that a stochastic process controls differentiation from the macroschizont to the merozoite stage. It was postulated that this process involves the presence of regulators of merozoite gene expression in the preceding stage of the life cycle, and that during differentiation a quantitative increase of these factors occurs. This study was carried out to test these postulations. Nuclear run-on analysis showed that TamS1 expression is controlled, at least in part, at the transcriptional level. The transcription start site showed homology with the consensus eukaryotic initiator motif, and study of the 5′ upstream region by the electrophoretic mobility-shift assay demonstrated that a 23 bp motif specifically bound factors from parasite-enriched nuclear extracts. Three complexes were shown to bind to a 9 bp core binding site (5′-TTTGTAGGG-3′). Two of these complexes were present in macroschizont extracts but were found at elevated levels during differentiation. Both complexes contain a polypeptide of the same molecular mass and may be related via the formation of homodimer or heterodimer complexes. The third complex appears to be distinct and was detected at time points associated with the transition to high level merozoite gene expression.

High expression of CD52 predicts poor prognosis of cytogenetic normal acute myeloid leukemia

2020 ◽  
Author(s):  
Ping Cai ◽  
Wenzhi Cai ◽  
Xiaoyu Xu ◽  
xiaofei Yang ◽  
yemin Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Myeloid Leukemia ◽  
Poor Prognosis ◽  
Leukemia Cell ◽  
Dna Demethylation ◽  
Rank Test ◽  
Log Rank Test ◽  
High Level ◽  
Acute Myeloid

Abstract Background: The prognosis of cytogenetic normal acute myeloid leukemia (CN-AML) varies. Finding new biomarkers affecting the prognosis of these patients may bring a new strategy for precise classification and treatment. CD52 play a significant role in chronic lymphocytic leukemia (CLL). However, the potential role of CD52 in CN-AML remains largely elusive. Methods: We analyzed the prognostic role of different expression levels of CD52 in 58 CN-AML from The Cancer Genome Atlas (TCGA) dataset and validate these results with 345 CN-AML patients from Gene Expression Omnibus (GEO) dataset. Results: CN-AML patients with high CD52 mRNA expression have a poorer prognosis compared to low CD52 expression ( event-free survival [EFS], P =0.056; overall survival [OS], P=0.043; log-rank test) and the results was verified by GSE12417 (OS, P=0.0197; log-rank test) and GSE71014 (OS, P=0.0197; log-rank test). Hematopoietic stem cell transplantation (HSCT) may improve prognosis of patients with CD52 high . Multivariate cox regression analysis show that the expression level of CD52 (HR=1.503; 95%CI:1.158-1.949 ; P=0.002) was a prognostic factor independent of age (HR=3.045; 95%CI:1.524-6.086; P=0.002) and FLT3 mutation status (HR=2.219; 95%CI:1.123-4.382; P=0.022). CD52 gene expression show a predictive effect on EFS (1-year survival- area under the curve [AUC]:0.685, 2-year survival-AUC:0.752) and OS (1-year survival-AUC: 0.717, 2-year survival-AUC:0.770). Besides, we also found that there is a significant negative correlation between CD52 mRNA expression and DNA methylation . CD52 DNA demethylation may responsible for the high level of CD52 mRNA. Functional enrichment analysis of differentially expressed genes in CD52 high and CD52 low suggests that leukemia cell adhesion-related pathways may be associated with poor prognosis in CD52 high patients . Conclusions: CD52 gene mRNA overexpression is an independent adverse prognostic factor for CN-AML, which could be reversed by HSCT. CD52 DNA demethylation may responsible for the high level of CD52 mRNA. The poor prognosis of patients with CD52 high may involves in leukemia cell adhesion-related pathways. Whether CD52 monoclonal antibodies play a role in high risk patients need further research.

Sign in / Sign up

Export Citation Format

Share Document