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101.
MexAB-OprM is known to pump out mostly lipophilic and amphiphilic drugs. But in low-ionic-strength medium, nutrient broth (NB), this pump has been shown to contribute to hydrophilic antibiotic (aminoglycosides) resistance, via active efflux. The association of the MexAB-OprM efflux system to aminoglycosides resistance inPseudomonas aeruginosa were assessed using a drug susceptibility test carried out in NB, in presence and absence of protonophore, carbonyl cyanide m-chlorophenyl hydrazone (CCCP) by 23 multidrug resistant strains were selected from 104 clinical isolates ofP. aeruginosa. Active efflux was assessed using EtBr accumulation assays. PCR was used to identify themexAB-oprM and MexAB-OprM-dependent efflux of aminoglycosides and the results were confirmed by continuous fluorescence assay. A multidrug resistant mutant ofmexAB-oprM, derivative of PAO1, was selected by ciprofloxacin and subjected to the same analysis as described above for the clinical isolates. In this study, CCCP reduced the level of MICs in at least 1 dilution. Ethidium bromide accumulation assays confirmed the presence of efflux mechanism in all clinical isolates and PCR demonstrated that 17% of our isolates had themexAB-oprM operon. Results of aminoglycosides accumulation showed, in addition to amphiphilic antibiotics in NB medium, MexAB-OprM extrudes aminoglycosides (hydrophilic) drugs. 相似文献
102.
Jia H Bagherzadeh A Hartzoulakis B Jarvis A Löhr M Shaikh S Aqil R Cheng L Tickner M Esposito D Harris R Driscoll PC Selwood DL Zachary IC 《The Journal of biological chemistry》2006,281(19):13493-13502
Neuropilin-1 (NP-1) is a receptor for vascular endothelial growth factor-A165 (VEGF-A165) in endothelial cells. To define the role of NP-1 in the biological functions of VEGF, we developed a specific peptide antagonist of VEGF binding to NP-1 based on the NP-1 binding site located in the exon 7- and 8-encoded VEGF-A165 domain. The bicyclic peptide, EG3287, potently (K(i) 1.2 microM) and effectively (>95% inhibition at 100 microM) inhibited VEGF-A165 binding to porcine aortic endothelial cells expressing NP-1 (PAE/NP-1) and breast carcinoma cells expressing only NP-1 receptors for VEGF-A, but had no effect on binding to PAE/KDR or PAE/Flt-1. Molecular dynamics calculations, a nuclear magnetic resonance structure of EG3287, and determination of stability in media, indicated that it constitutes a stable subdomain very similar to the corresponding region of native VEGF-A165. The C terminus encoded by exon 8 and the three-dimensional structure were both critical for EG3287 inhibition of NP-1 binding, whereas modifications at the N terminus had little effect. Although EG3287 had no direct effect on VEGF-A165 binding to KDR receptors, it inhibited cross-linking of VEGF-A165 to KDR in human umbilical vein endothelial cells co-expressing NP-1, and inhibited stimulation of KDR and PLC-gamma tyrosine phosphorylation, activation of ERKs1/2 and prostanoid production. These findings characterize the first specific antagonist of VEGF-A165 binding to NP-1 and demonstrate that NP-1 is essential for optimum KDR activation and intracellular signaling. The results also identify a key role for the C-terminal exon 8 domain in VEGF-A165 binding to NP-1. 相似文献
103.
R. Spence † M. K. Fatema ‡ M. Reichard § K. A. Huq M. A. Wahab ‡ Z. F. Ahmed ‡ C. Smith 《Journal of fish biology》2006,69(5):1435-1448
The present study presents the results of a survey of a wide range of water bodies in Bangladesh to identify and describe Danio rerio habitat preferences. Field-based experiments were conducted to determine the vertical distribution of D. rerio in the water column, together with five other fish species commonly found in association with D. rerio. Danio rerio is a floodplain rather than riverine species, being most abundant in shallow lakes, ponds and ditches, typically in open locations with relatively clear water and abundant vegetation at the margins. It is commonly found in water bodies with a connection to rice cultivation and is more common in the north of Bangladesh than the south. Danio rerio occupies the whole of the water column and is observed as frequently in open water as amongst aquatic vegetation. 相似文献
104.
Mohammad Mustafizur Rahman Shusaku Kadowaki Stephen Richard Balcombe Md. Abdul Wahab 《Ecological Research》2010,25(2):303-309
We used customized fish tanks as model fish ponds to observe grazing, swimming, and conspecific social behavior of common
carp (Cyprinus carpio) under variable food-resource conditions to assess alterations in feeding niche. Different food and feeding situations were
created by using only pond water or pond water plus pond bottom sediment or pond water plus pond bottom sediment and artificial
feeding. All tanks were fertilized twice, prior to stocking and 2 weeks later after starting the experiment to stimulate natural
food production. Common carp preferred artificial feed over benthic macroinvertebrates, followed by zooplankton. Common carp
did not prefer any group of phytoplankton in any treatment. Common carp was mainly benthic in habitat choice, feeding on benthic
macroinvertebrates when only plankton and benthic macroinvertebrates were available in the system. In the absence of benthic
macroinvertebrates, their feeding niche shifted from near the bottom of the tanks to the water column where they spent 85%
of the total time and fed principally on zooplankton. Common carp readily switched to artificial feed when available, which
led to better growth. Common carp preferred to graze individually. Behavioral observations of common carp in tanks yielded
new information that assists our understanding of their ecological niche. This knowledge could be potentially used to further
the development of common carp aquaculture. 相似文献
105.
Muhammad Dain Yazid Shahrul Hisham Zainal Ariffin Sahidan Senafi Mohamad Abdul Razak Rohaya Megat Abdul Wahab 《Cancer cell international》2010,10(1):42
Background
The main morphological features of primitive cells, such as stem and progenitor cells, are that these cells consists only one nucleus. The main purpose of this study was to determine the differentiation capacities of stem and progenitor cells. This study was performed using mononucleated cells originated from murine peripheral blood and MC3T3-E1 cells. Three approaches were used to determine their differentiation capacities: 1) Biochemical assays, 2) Gene expression analysis, and 3) Morphological observations. 相似文献106.
Ali El-Armouche Azadeh Wahab Katrin Wittköpper Thomas Schulze Lutz Pohlmann Jenna F. DuMond Rainer H. Böger Thomas Eschenhagen Lucie Carrier Sonia Donzelli 《Biochemical and biophysical research communications》2010,402(2):340-1698
Contractile dysfunction and diminished response to β-adrenergic agonists are characteristics for failing hearts. Chemically donated nitroxyl (HNO) improves contractility in failing hearts and thus may have therapeutic potential. Yet, there is a need for pharmacologically suitable donors. In this study we tested whether the pure and long acting HNO donor, 1-nitrosocyclohexyl acetate (NCA), affects contractile force in normal and pathological ventricular myocytes (VMs) as well as in isolated hearts. VMs were isolated from mice either subjected to isoprenaline-infusion (ISO; 30 μg/g per day) or to vehicle (0.9% NaCl) for 5 days. Sarcomere shortening and Ca2+ transients were simultaneously measured using the IonOptix system. Force of contraction of isolated hearts was measured by a Langendorff-perfusion system. NCA increased peak sarcomere shortening by + 40-200% in a concentration-dependent manner (EC50 ∼55 μM). Efficacy and potency did not differ between normal and chronic ISO VMs, despite the fact that the latter displayed a markedly diminished inotropic response to acute β-adrenergic stimulation with ISO (1 μM). NCA (60 μM) increased peak sarcomere shortening and Ca2+ transient amplitude by ∼200% and ∼120%, respectively, suggesting effects on both myofilament Ca2+ sensitivity and sarcoplasmic reticulum (SR) Ca2+ cycling. Importantly, NCA did not affect diastolic Ca2+ or SR Ca2+ content, as assessed by rapid caffeine application. NCA (45 μM) increased force of contraction by 30% in isolated hearts. In conclusion, NCA increased contractile force in normal and β-adrenergically desensitized VMs as well as in isolated mouse hearts. This profile warrants further investigations of this HNO donor in the context of heart failure. 相似文献
107.
Bahareh Hakiminia Arash Goudarzi Azadeh Moghaddas 《Journal of biochemical and molecular toxicology》2019,33(8)
Cisplatin is one of the highly consumed and effective antitumor agents whose clinical application is accompanied by nephrotoxicity adverse reaction. Also, other complications such as ototoxicity and hepatotoxicity are a matter of concern. Today, it is suggested that cisplatin‐associated toxicities are mainly induced by free radicals production, which will result in oxidative organ injury. The evidence is growing over the protective effects of antioxidants on cisplatin‐induced adverse reactions especially nephrotoxicity. The possible protective effects of vitamin E and its derivative in cisplatin‐induced nephrotoxicity and ototoxicity are reviewed here at the light of pertinent results from basic and clinical research. Administration of vitamin E alone or in combination with other antioxidant agents could cause amelioration in oxidative stress biomarkers such as decreasing the level of malondialdehyde, reducing serum urea and creatinine, and also enhancing the activities of renal antioxidant enzymes including renal catalase, glutathione‐S‐transferase, and superoxide dismutase. Although the data from most of the studies are in favors of protective effects of vitamin E against cisplatin‐induced toxicity, more clinical trials are needed to clarify the clinical importance of vitamin E administration as an antioxidant during cisplatin therapy in cancer condition. 相似文献
108.
Azadeh Askarinejad 《Inorganica chimica acta》2006,359(10):3379-3383
A three-dimensional polymeric KITlI heterometallic compound [K2Tl(μ-C4H4O4)(μ-NO3)]n, with mixes succinate and nitrate ligands, has been synthesized and characterized. Its single-crystal X-ray structure shows two types of K+-ions with coordination numbers of seven and eight and one Tl+-ion with a coordination number of five. However, the arrangement of O-atoms for TlI suggests a gap or hole in the coordination geometry around this atom. This ‘hole’ is possibly occupied by a stereochemically ‘active’ electron lone pair of thallium atoms. Two hydrogen atoms of succinate situated 3.26 Å above the proposed site on the lone pair of TlI is oriented in such a way that it might be thought to be forming weak Tl-Lp?H-C hydrogen bond or agostic interactions, thus attaining of environment TlO5H2. 相似文献
109.
110.
Naser Ahmadbeigi Ehsan Seyedjafari Yousof Gheisari Amir Atashi Azadeh Omidkhoda Masoud Soleimani 《Cell biology international》2010,34(7):687-692
Umbilical cord blood‐derived USSCs (unrestricted somatic stem cells) have recently been considered as a potential source for stem cell therapy and transplantation due to their characteristics such as easy accessibility, low immunogenicity, self‐renewing and multilineage differentiation potential. Stem cell homing is a key factor in successful transplantation, which is regulated by CXCR4 in stem cells. In this study, we evaluated the expression of CXCR4 in USSCs different passages. Moreover, the effect of VEGF (vascular endothelial growth factor) and IGF‐1 (insulin‐like growth factor 1) on its expression was assessed. It was shown that the expression of CXCR4 in USSCs decreased with the increase in passage number. It was also revealed that VEGF increased surface expression and mRNA level of CXCR4 in USSCs, while IGF‐1 decreased its expression. When VEGF and IGF‐1 were administered simultaneously, CXCR4 expression was increased, but the expression level was less than VEGF alone. Finally, it was shown that over‐expression of CXCR4 enhanced the migratory capacity of USSCs. The increase of CXCR4 expression, here caused by VEGF in USSCs, can improve the efficacy of stem cell therapy and transplantation after long‐term culture of stem cells before clinical use. 相似文献