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Efflux pumps

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https://www.readbyqxmd.com/read/28101766/crossing-the-blood-brain-barrier-recent-advances-in-drug-delivery-to-the-brain
#1
Mayur M Patel, Bhoomika M Patel
CNS disorders are on the rise despite advancements in our understanding of their pathophysiological mechanisms. A major hurdle to the treatment of these disorders is the blood-brain barrier (BBB), which serves as an arduous janitor to protect the brain. Many drugs are being discovered for CNS disorders, which, however fail to enter the market because of their inability to cross the BBB. This is a pronounced challenge for the pharmaceutical fraternity. Hence, in addition to the discovery of novel entities and drug candidates, scientists are also developing new formulations of existing drugs for brain targeting...
January 18, 2017: CNS Drugs
https://www.readbyqxmd.com/read/28098416/motuporamine-derivatives-as-antimicrobial-agents-and-antibiotic-enhancers-against-resistant-gram-negative-bacteria
#2
Diane Borselli, Marine Blanchet, Jean-Michel Bolla, Aaron Muth, Kristen Skruber, Otto Phanstiel, Jean Michel Brunel
Dihydromotuporamine C and its derivatives were evaluated for their in vitro antimicrobial activities and antibiotic enhancement properties against Gram-negative bacteria and clinical isolates. The mechanism of action of one of these derivatives, MOTU-N44, was investigated against Enterobacter aerogenes by using fluorescent dyes to evaluate outer-membrane depolarization and permeabilization. Its efficiency correlated with inhibition of dye transport, thus suggesting that these molecules inhibit drug transporters by de-energization of the efflux pump rather than by direct interaction of the molecule with the pump...
January 18, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28096160/determinants-of-antibacterial-spectrum-and-resistance-potential-of-the-elongation-factor-g-inhibitor-argyrin-b-in-key-gram-negative-pathogens
#3
Adriana K Jones, Angela L Woods, Kenneth T Takeoka, Xiaoyu Shen, Jun-Rong Wei, Ruth E Caughlan, Charles R Dean
Argyrins are natural products with antibacterial activity against Gram-negative pathogens such as P. aeruginosa, B. multivorans and S. maltophilia We previously showed that argyrin B targets elongation factor G (FusA). Here we show that Argyrin B activity against P. aeruginosa PAO1 (MIC = 8 μg/mL) was not affected by deletion of the MexAB-OprM, MexXY-OprM, MexCD-OprJ or MexEF-OprN efflux pumps. However, argyrin B induced expression of MexXY causing a slight but reproducible antagonism with the MexXY substrate antibiotic ciprofloxacin...
January 17, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28096157/resistance-to-thiacetazone-derivatives-active-against-mycobacterium-abscessus-involves-mutations-in-the-mmpl5-transcriptional-repressor-mab_4384
#4
Iman Halloum, Albertus Viljoen, Varun Khanna, Derek Craig, Christiane Bouchier, Roland Brosch, Geoffrey Coxon, Laurent Kremer
Available chemotherapeutic options are very limited against Mycobacterium abscessus, which imparts a particular challenge in the treatment of cystic fibrosis (CF) patients infected with this rapid-growing mycobacterium. New drugs are urgently needed against this emerging pathogen, but the discovery of active chemotypes has not been performed intensively. Interestingly, however, the repurposing of thiacetazone (TAC), a drug once used to treat tuberculosis, has increased following the deciphering of its mechanism of action and the detection of significantly more potent analogues...
January 17, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28095895/genome-wide-snp-analysis-using-2b-rad-sequencing-identifies-the-candidate-genes-putatively-associated-with-resistance-to-ivermectin-in-haemonchus-contortus
#5
Xiaoping Luo, Xiaona Shi, Chunxiu Yuan, Min Ai, Cheng Ge, Min Hu, Xingang Feng, Xiaoye Yang
BACKGROUND: The excessive and uncontrolled use of anthelmintics, e.g. ivermectin (IVM) for the treatment of livestock parasites has led to widespread resistance in gastrointestinal nematodes, such as Haemonchus contortus. There is an urgent need for better management of drug-use in nematode control and development of novel anthelmintics. Discovery and identification of anthelmintic resistance-associate molecules/markers can provide a basis for rational anthelmintics-use and development of novel drugs...
January 17, 2017: Parasites & Vectors
https://www.readbyqxmd.com/read/28090273/the-effects-of-berberine-and-palmatine-on-efflux-pumps-inhibition-with-different-gene-patterns-in-pseudomonas-aeruginosa-isolated-from-burn-infections
#6
Seyed Sajjad Aghayan, Hamidreza Kalalian Mogadam, Mozhgan Fazli, Davood Darban-Sarokhalil, Seyed Sajjad Khoramrooz, Fereshteh Jabalameli, Somayeh Yaslianifard, Mehdi Mirzaii
BACKGROUND: Related Multidrug Resistance (MDR) to efflux pumps is a significant problem in treating infections caused by Pseudomonas aeruginosa (P. aeruginosa). Plant compounds have been identified as Pump Inhibitors (EPIs). In the current study, the potential effect of Berberine and Palmatine as EPIs were investigated on efflux pump inhibition through focusing on different gene patterns in P. aeruginosa isolated from burn infections. METHODS: All isolates were collected and identified using the standard biochemical tests...
January 2017: Avicenna Journal of Medical Biotechnology
https://www.readbyqxmd.com/read/28089787/antituberculosis-drugs-reducing-efflux-increasing-activity
#7
REVIEW
Liliana Rodrigues, Tanya Parish, Meenakshi Balganesh, José A Ainsa
In mycobacteria, it was assumed that efflux pumps only had a marginal role in drug resistance. In recent years, owing to the need to find novel drugs against multidrug-resistant tuberculosis, it has become clear that efflux should not be ignored. Although efflux inhibitors have been very useful for characterizing in vitro the properties of efflux pumps, their usefulness in vivo is limited because of their toxicity. Alternatively, programs aimed at discovering novel drugs for treating tuberculosis should implement strategies to characterize efflux liability of candidate drugs...
January 12, 2017: Drug Discovery Today
https://www.readbyqxmd.com/read/28088472/cholesterol-and-ergosterol-affect-the-activity-of-staphylococcus-aureus-antibiotic-efflux-pumps
#8
S R Tintino, C D M Oliveira-Tintino, F F Campina, M S Costa, R P Cruz, R L S Pereira, J C Andrade, E O Sousa, J P Siqueira-Junior, H D M Coutinho, T C Leal-Balbino, V Q Balbino
The aim of this study is to evaluate the effect of ergosterol on steroids and cholesterol efflux pumps in multidrug resistant strains of S. aureus. Were used RN4220 harboring plasmid pUL5054, which carries the gene encoding the MsrA macrolide efflux protein; and IS-58, which possesses the TetK tetracycline efflux protein; 1199B resists hydrophilic fluoroquinolones via a NorA-mediated mechanism and wild strain 1199B. The Minimal Inhibitory Concentration (MIC) was determined and the evaluation of possible inhibition of efflux pumps by reduction of MIC...
January 11, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28080217/synergistic-effects-of-tetrandrine-with-posaconazole-against-aspergillus-fumigatus
#9
Shui-Xiu Li, Yan-Jun Song, Ling Jiang, Ya-Jing Zhao, Hui Guo, Dong-Mei Li, Kun-Ju Zhu, Hong Zhang
In our earlier in vitro and in vivo studies, synergistic effects were observed when itraconazole or voriconazole were combined with tetrandrine (TET) against Aspergillus fumigatus, and the synergistic mechanism was related to inhibition of the drug efflux pump. Posaconazole (PCZ) is a broad-spectrum triazole antifungal agent used for the treatment of diverse fungal infections, including aspergillosis and candidiasis. Herein, the antifungal effects of TET are further investigated in vitro and in vivo alone or combined with PCZ against 20 clinical isolates of A...
January 12, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28080212/heterogeneity-of-carbapenem-resistance-mechanisms-among-gram-negative-pathogens-in-lebanon-results-of-the-first-cross-sectional-countrywide-study
#10
Dalal Hammoudi Halat, Carole Ayoub Moubareck, Dolla Karam Sarkis
Carbapenem-resistant Gram-negative pathogens have progressively disseminated to different countries worldwide, presenting a serious public health concern. The aims of this study were to determine the prevalence of carbapenem resistance in Gram-negative bacteria in Lebanon, to elucidate molecular mechanisms, and to identify genetic relatedness of incriminated strains. Carbapenem nonsusceptible Enterobacteriaceae, Acinetobacter baumannii, and Pseudomonas were collected from 11 Lebanese hospitals in 2012. Antimicrobial susceptibility was assessed with phenotypic tests, genes encoding carbapenemases were screened via PCR-sequencing, and genetic relatedness was examined by PGFE and ERIC-PCR...
January 12, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28068430/molecular-mimics-of-classic-p-glycoprotein-inhibitors-as-multidrug-resistance-suppressors-and-their-synergistic-effect-on-paclitaxel
#11
Moustafa E El-Araby, Abdelsattar M Omar, Maan T Khayat, Hanan A Assiri, Ahmed M Al-Abd
P-glycoprotein (Pgp) is a membrane bound efflux pump spread in a variety of tumor cells and considered as a main component of multidrug resistance (MDR) to chemotherapies. In this work, three groups of compounds (imidazolone, oxazolone and vinyl dipeptide derivatives) were synthesized aiming to develop a molecular framework that effectively suppresses MDR. When tested for their influence on Pgp activity, four compounds coded Cur1-01, Cur1-12V, Curox-1 and Curox-3 significantly decreased remaining ATP concentration indicating Pgp substrate site blocking...
2017: PloS One
https://www.readbyqxmd.com/read/28062807/junctional-adhesion-molecule-a-expression-in-the-murine-epididymal-tract-and-accessory-organs-and-acquisition-by-maturing-sperm
#12
Kathie Z Wu, Kun Li, Deni S Galileo, Patricia A Martin-DeLeon
STUDY QUESTION: Is junctional adhesion molecule A (JAM-A), a sperm protein essential for normal motility, expressed in the murine post-testicular pathway and involved in sperm maturation? SUMMARY ANSWER: JAM-A is present in the prostate and seminal vesicles and in all three regions of the epididymis where it is secreted in epididymosomes in the luminal fluid and can be delivered to sperm in vitro. WHAT IS KNOWN ALREADY: JAM-A shares with the plasma membrane Ca(2+)ATPase 4 (PMCA4, the major Ca(2+) efflux pump in murine sperm) a common interacting partner, CASK (Ca(2+)/CaM-dependent serine kinase)...
January 6, 2017: Molecular Human Reproduction
https://www.readbyqxmd.com/read/28062386/rna-expression-analysis-of-efflux-pump-genes-in-clinical-isolates-of-multidrug-resistant-and-extensively-drug-resistant-mycobacterium-tuberculosis-in-south-korea
#13
Tae Sang Oh, Young Jin Kim, Hee Yoon Kang, Chang-Ki Kim, Sun Young Cho, Hee Joo Lee
Tuberculosis (TB), caused by infection with Mycobacterium tuberculosis, is an important communicable disease. Various mechanisms of resistance to antituberculosis drugs have been reported; these are principally mutations in target genes. However, not all M. tuberculosis resistance can be explained by mutations in such genes. Other resistance mechanisms associated with drug transport, such as efflux pumps, have also been reported. In this study, we investigated the expression levels of three putative efflux pumps and mutations in target genes associated with injectable agents and fluoroquinolones with clinical MDR and XDR-TB isolates...
January 3, 2017: Infection, Genetics and Evolution
https://www.readbyqxmd.com/read/28062292/use-of-carvacrol-thymol-and-eugenol-for-biofilm-eradication-and-resistance-modifying-susceptibility-of-salmonella-enterica-serovar-typhimurium-strains-to-nalidixic-acid
#14
Hanene Miladi, Tarek Zmantar, Bochra Kouidhi, Yassine Chaabouni, Kacem Mahdouani, Amina Bakhrouf, Kamel Chaieb
The Aims of the study was to evaluate the antibacterial susceptibility and the biofilm eradication of three natural compounds carvacrol (CAR), thymol (TH) and eugenol (EUG), alone or in combination with nalidixic acid (NA) against twelve Salmonella Typhimurium strains. The minimum inhibitory concentration (MIC) and the minimum biofilm eradication concentration (BEC50) of the tested compounds (CAR, TH and EUG) and their combinations with NA were evaluated. In order to assess whether these bacteria had active efflux pumps, ethidium bromide (EtBr) accumulation assays was achieved using spectrophotometric accumulation assays...
January 3, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28060821/customized-regulation-of-diverse-stress-response-genes-by-the-multiple-antibiotic-resistance-activator-mara
#15
Nicholas A Rossi, Mary J Dunlop
Stress response networks frequently have a single upstream regulator that controls many downstream genes. However, the downstream targets are often diverse, therefore it remains unclear how their expression is specialized when under the command of a common regulator. To address this, we focused on a stress response network where the multiple antibiotic resistance activator MarA from Escherichia coli regulates diverse targets ranging from small RNAs to efflux pumps. Using single-cell experiments and computational modeling, we showed that each downstream gene studied has distinct activation, noise, and information transmission properties...
January 6, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28054667/yersinia-pestis-halotolerance-illuminates-plague-reservoirs
#16
Maliya Alia Malek, Idir Bitam, Anthony Levasseur, Jérôme Terras, Jean Gaudart, Said Azza, Christophe Flaudrops, Catherine Robert, Didier Raoult, Michel Drancourt
The plague agent Yersinia pestis persists for years in the soil. Two millennia after swiping over Europe and North Africa, plague established permanent foci in North Africa but not in neighboring Europe. Mapping human plague foci reported in North Africa for 70 years indicated a significant location at <3 kilometers from the Mediterranean seashore or the edge of salted lakes named chotts. In Algeria, culturing 352 environmental specimens naturally containing 0.5 to 70 g/L NaCl yielded one Y. pestis Orientalis biotype isolate in a 40 g/L NaCl chott soil specimen...
January 5, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28052140/a-novel-zn2-cys6-transcription-factor-atrr-plays-a-key-role-in-an-azole-resistance-mechanism-of-aspergillus-fumigatus-by-co-regulating-cyp51a-and-cdr1b-expressions
#17
Daisuke Hagiwara, Daisuke Miura, Kiminori Shimizu, Sanjoy Paul, Ayumi Ohba, Tohru Gonoi, Akira Watanabe, Katsuhiko Kamei, Takahiro Shintani, W Scott Moye-Rowley, Susumu Kawamoto, Katsuya Gomi
Successful treatment of aspergillosis caused by Aspergillus fumigatus is threatened by an increasing incidence of drug resistance. This situation is further complicated by the finding that strains resistant to azoles, the major antifungal drugs for aspergillosis, have been widely disseminated across the globe. To elucidate mechanisms underlying azole resistance, we identified a novel transcription factor that is required for normal azole resistance in Aspergillus fungi including A. fumigatus, Aspergillus oryzae, and Aspergillus nidulans...
January 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28051334/glutamine-attenuates-obstructive-cholestasis-in-rats-via-farnesoid-x-receptor-mediated-regulation-of-bsep-and-mrp2
#18
Bingli Liu, Yiming Li, Hong Ji, Hongwei Lu, Hua Li, Yakun Shi
To investigate the protective effect of glutamine (Gln) against obstructive cholestasis in association with farnesoid X receptor (FXR) activation, an obstructive cholestasis model was established in male Sprague-Dawley rats by bile duct ligation (BDL). Serum biomarkers and hematoxylin plus eosin staining were used to identify the degree of hepatic injury in the rats with obstructive cholestasis after Gln treatment. Immunohistochemistry, real-time PCR, Western blot, cultured primary rat hepatocytes with FXR knockdown, and dual-luciferase reporter assay were performed to elucidate the mechanisms underlying Gln hepatoprotection...
October 5, 2016: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28044273/rnd-efflux-pump-mediated-antibiotic-resistance-in-gram-negative-bacteria-escherichia-coli-and-pseudomonas-aeruginosa-a-major-issue-worldwide
#19
REVIEW
Minakshi Puzari, Pankaj Chetia
Therapeutic failures against diseases due to resistant Gram-negative bacteria have become a major threat nowadays as confirmed by surveillance reports across the world. One of the methods of development of multidrug resistance in Escherichia coli and Pseudomonas aeruginosa is by means of RND efflux pumps. Inhibition of these pumps might help to combat the antibiotic resistance problem, for which the structure and regulation of the pumps have to be known. Moreover, judicious antibiotic use is needed to control the situation...
February 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28043640/alternate-efflux-pump-mechanism-may-contribute-to-drug-resistance-in-extensively-drug-resistant-isolates-of-mycobacterium-tuberculosis
#20
Akbar Kanji, Rumina Hasan, Ambreen Zaver, Asho Ali, Kehkashan Imtiaz, Mussarat Ashraf, Taane G Clark, Ruth McNerney, Samreen Shafiq, Zahra Hasan
INTRODUCTION: Extensively drug-resistant tuberculosis (XDR-TB) has emerged as one of the biggest threats to public health and TB control programs worldwide. XDR-TB is caused by Mycobacterium tuberculosis (MTB) strains resistant to rifampin and isoniazid, as well as to a fluoroquinolone and to at least one injectable aminoglycoside. Drug resistance in MTB has primarily been associated with single nucleotide polymorphisms (SNPs) in particular genes. However, it has also been shown that efflux pumps may play a role in resistance of MTB...
December 2016: International Journal of Mycobacteriology
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