Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We designed phosphorothioate-modified DNA probes linked to superparamagnetic iron oxide nanoparticles (SPION) for in vivo magnetic resonance imaging (MRI) of fosB and Delta fosB mRNA after amphetamine (AMPH) exposure in mice. Specificity of both the fosB and Delta fosB probes was verified by in vitro reverse transcriptase-PCR amplification to a single fragment of total cDNA obtained from acutely AMPH-exposed mouse brains. We confirmed time-dependent uptake and retention profiles of both probes in neurons of GAD67-green fluorescent protein knock-in mice. MRI signal of SPION-labeled fosB probe delivered via intracerebroventricular route was elevated in both acutely and chronically AMPH-exposed mice; the signal was suppressed by dopaminergic receptor antagonist pretreatment. SPION-labeled Delta fosB probe signal elevation occurred only in chronically AMPH-exposed mice. The in vivo target specificity of these probes permits reliable MRI visualization of AMPH-induced differential elevations of fosB and Delta fosB mRNA in living brains.
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PMID:DNA-based MRI probes for specific detection of chronic exposure to amphetamine in living brains. 1971 Mar 18

Abstract A diverse assemblage of diazotrophic bacteria exists in the rhizosphere of the smooth cordgrass, Spartina alterniflora, but the taxa actively involved in nitrogen fixation have not been determined. In order to identify the diazotrophs that were actively expressing nifH, the gene encoding the nitrogenase iron protein, mRNA was extracted from Spartina rhizosphere samples and nifH-specific seminested reverse transcriptase-PCR performed. Expressed nifH sequences were recovered from organisms affiliated with the (gamma-+beta-) Proteobacteria and the anaerobes. Most of the expressed nifH sequences were highly similar (>/=95% similarity) to sequences previously recovered from Spartina rhizosphere DNA using conventional nifH-specific PCR. These sequences were also similar, although not identical to the nifH sequences of Pseudomonas stutzeri, Vibrio diazotrophicus, Desulfovibrio africanus, and Desulfovibrio gigas.
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PMID:Expression of nifH genes by diazotrophic bacteria in the rhizosphere of short form Spartina alterniflora. 1971 72

Iron overload induced by brain ischemia has been shown to be involved in neurodegenerative disease. Little is known about the relationship between brain ischemia and ferroportin 1 (FP1). The aims of this study are: (i) to determine whether iron accumulation in the brain is induced by cerebral hypoperfusion; and (ii) to test whether expression of FP1 is influenced by cerebral ischemia. The common carotid arteries (CCA) of rats were ligated bilaterally to induce cerebral ischemia, and the iron concentration of the cortex and hippocampus was measured by graphite furnace atomic absorption spectrometry. Iron was stained by Perl's method. The expression of FP1 mRNA and protein was shown by the reverse transcriptase polymerase chain reaction and immunohistochemical methods. The iron concentration in the cortex and hippocampus of ischemic rats had increased on day 7 (CCA7) and significantly on day 28 (CCA28) compared to control rats. More iron granules had been deposited in the cerebral cortex and hippocampus in rats with bilaterally ligated CCA on CCA7 and CCA28. In ischemic rats, FP1 expression in the cerebral cortex and hippocampus was decreased by CCA7 and this was more marked by CCA28 compared to control rats. We therefore concluded that iron deposition in the cerebral cortex and hippocampus of rats is induced by cerebral ischemia. Iron deposition may be attributed to the decrease in FP1 expression, and this inhibition of FP1 expression could be a major contributor to the formation of iron deposits in cerebral ischemia.
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PMID:Quantitative analysis of iron concentration and expression of ferroportin 1 in the cortex and hippocampus of rats induced by cerebral ischemia. 1976 98

Abnormally high levels of iron are observed in the brain of patients suffering from neurodegenerative disorders. The mechanisms involved in iron accumulation in neurodegenerative disorders remain poorly understood. In the present study we investigated the effects of aging and neonatal iron overload on the mRNA expression of proteins critically involved in controlling iron homeostasis. Wistar rat pups received a single daily dose of vehicle or iron (10 mg/kg of b.w. of Fe(2+)), at postnatal days 12-14. The expression of Transferrin Receptor (TfR), H-Ferritin, and IRP2 were analyzed by a semi-quantitative reverse transcriptase polymerase chain reaction assay in cortex, hippocampus and striatum of rats sacrificed at three different ages (15-day-old; 90-day-old and 2-year old rats). Results indicate that TfR, H-ferritin, and IRP2 mRNA expression was differentially affected by aging and by neonatal iron treatment in all three brain regions. These findings might have implications for the understanding of iron homeostasis misregulation associated with neurodegenerative disorders.
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PMID:mRNA expression of proteins involved in iron homeostasis in brain regions is altered by age and by iron overloading in the neonatal period. 1994 90

Helicobacter hepaticus is an enterohepatic bacterium associated with inflammatory bowel disease in children and causes severe hepatobiliary disorders in mice. To elucidate the molecular response of H. hepaticus to bovine bile, a proteomic investigation was conducted. Bacteria were grown for 48 h in liquid media supplemented with different concentrations of bovine bile to determine its effects on bacterial growth and morphology. Protein expression profiles of bacteria grown at a bile concentration of 0.1% and in the absence of bile were obtained using two-dimensional gel electrophoresis. Gel spots with differences in intensities greater than 2-fold between both conditions were determined, and 55 differentially expressed proteins were identified using tandem mass spectrometry. Identified proteins participate in various biological functions including cell envelope biosynthesis, cell response to stress, iron homeostasis and transport, motility, primary and secondary metabolism, and virulence. Changes in the expression of H. hepaticus genes related to proteins involved in virulence and oxidative stress that were differentially expressed in the presence of bile were investigated using real-time reverse transcriptase PCR. The results indicated that the effects of bile on H. hepaticus included a strong response to oxidative stress and an expression of factors that can promote host colonization.
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PMID:Response of Helicobacter hepaticus to bovine bile. 2007 36

Ferritins are conserved iron storage proteins that exist in most living organisms and play an essential role in iron homeostasis. In this study, we reported the identification and analysis a ferritin M subunit, SmFerM, from turbot Scophthalmus maximus. The full length cDNA of SmFerM contains a 5'-untranslated region (UTR) of 232 bp, an open reading frame (ORF) of 531 bp, and a 3'-UTR of 196 bp. The ORF encodes a putative protein of 176 amino acids, which shares extensive sequence identities with the M ferritins of several fish species. In silico analysis identified in SmFerM both the ferroxidase center of mammalian H ferritins and the iron nucleation site of mammalian L ferritins. Quantitative real time reverse transcriptase-PCR analysis indicated that SmFerM expression was highest in muscle and lowest in heart and responded positively to experimental challenges with bacterial pathogens and poly(I:C). Exposure of cultured turbot hepatocytes to treatment of stress inducers (iron, copper, and H(2)O(2)) significantly upregulated the expression of SmFerM in a dose dependent manner. Iron chelating analysis showed that recombinant SmFerM purified from Escherichia coli exhibited apparent iron binding activity. These results suggest that SmFerM is a functional M ferritin and is likely to play a role in iron sequestration and protection against oxidative stress and microbial infection.
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PMID:Identification and analysis of a Scophthalmus maximus ferritin that is regulated at transcription level by oxidative stress and bacterial infection. 2038 53

Despite significant advances in highly active antiretroviral therapy (HAART), the prevalence of neuroAIDS remains high. This is mainly attributed to inability of antiretroviral therapy (ART) to cross the blood-brain barrier (BBB), thus resulting in insufficient drug concentration within the brain. Therefore, development of an active drug targeting system is an attractive strategy to increase the efficacy and delivery of ART to the brain. We report herein development of magnetic azidothymidine 5'-triphosphate (AZTTP) liposomal nanoformulation and its ability to transmigrate across an in vitro BBB model by application of an external magnetic field. We hypothesize that this magnetically guided nanoformulation can transverse the BBB by direct transport or via monocyte-mediated transport. Magnetic AZTTP liposomes were prepared using a mixture of phosphatidyl choline and cholesterol. The average size of prepared liposomes was about 150 nm with maximum drug and magnetite loading efficiency of 54.5% and 45.3%, respectively. Further, magnetic AZTTP liposomes were checked for transmigration across an in vitro BBB model using direct or monocyte-mediated transport by application of an external magnetic field. The results show that apparent permeability of magnetic AZTTP liposomes was 3-fold higher than free AZTTP. Also, the magnetic AZTTP liposomes were efficiently taken up by monocytes and these magnetic monocytes showed enhanced transendothelial migration compared to normal/non-magnetic monocytes in presence of an external magnetic field. Thus, we anticipate that the developed magnetic nanoformulation can be used for targeting active nucleotide analog reverse transcriptase inhibitors to the brain by application of an external magnetic force and thereby eliminate the brain HIV reservoir and help to treat neuroAIDS.
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PMID:Magnetic nanoformulation of azidothymidine 5'-triphosphate for targeted delivery across the blood-brain barrier. 2046 31

Catechins and their polymers procyanidins are health-promoting flavonoids found in edible vegetables and fruits. They act as antioxidants by scavenging reactive oxygen species and by chelating the redox-active metals iron and copper. They also behave as signaling molecules, modulating multiple cell signalling pathways and gene expression, including that of antioxidant enzymes. This study aimed at determining whether catechins and procyanidins interact with the redox-inactive metal zinc and at assessing their effect on cellular zinc homeostasis. We found that a grape-seed procyanidin extract (GSPE) and the green tea flavonoid (-)-epigallocatechin-3-gallate (EGCG) bind zinc cations in solution with higher affinity than the zinc-specific chelator Zinquin, and dose-dependently prevent zinc-induced toxicity in the human hepatocarcinoma cell line HepG2, evaluated by the lactate dehydrogenase test. GSPE and EGCG hinder intracellular accumulation of total zinc, measured by atomic flame absorption spectrometry, concomitantly increasing the level of cytoplasmic labile zinc detectable by Zinquin fluorescence. Concurrently, GSPE and EGCG inhibit the expression, evaluated at the mRNA level by quantitative reverse transcriptase-polymerase chain reaction, of zinc-binding metallothioneins and of plasma membrane zinc exporter ZnT1 (SLC30A1), while enhancing the expression of cellular zinc importers ZIP1 (SLC39A1) and ZIP4 (SLC39A4). GSPE and EGCG also produce all these effects when HepG2 cells are stimulated to import zinc by treatment with supplemental zinc or the proinflammatory cytokine interleukin-6. We suggest that extracellular complexation of zinc cations and the elevation of cytoplasmic labile zinc may be relevant mechanisms underlying the modulation of diverse cell signaling and metabolic pathways by catechins and procyanidins.
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PMID:Dietary catechins and procyanidins modulate zinc homeostasis in human HepG2 cells. 2047 14

The marine fish pathogen Photobacterium damselae subsp. piscicida utilizes haem compounds as the sole iron source. In a previous work, we characterized a gene cluster with ten potential haem uptake and utilization genes. Two of these genes, hutC and hutD, which are iron-regulated, conform a putative inner membrane haem ABC transporter. In this study, we constructed an insertional mutant, leading to the inactivation of hutCD genes. Reverse transcriptase-PCR analyses demonstrated that an insertion between the hutB and hutC genes abolished transcription of the downstream hutC and hutD genes. The hutCD mutant was unable to utilize haem as the sole iron source, demonstrating that the putative ABC-transporter proteins HutC and HutD are essential for haem utilization as an iron source in P. damselae subsp. piscicida. In addition, reverse transcriptase-PCR assays conducted with RNA samples isolated from experimentally infected fish revealed the presence of hutCD transcripts. The results demonstrate for the first time that haem uptake genes of a fish pathogen are expressed during the infective process in fish.
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PMID:The ABC-transporter hutCD genes of Photobacterium damselae subsp. piscicida are essential for haem utilization as iron source and are expressed during infection in fish. 2056 Nov 40

Calcium-sensing receptors (CaSR) are G-protein coupled receptors which maintain systemic calcium haemeostasis, participate in hormone secretion, activation of iron channel, cell apoptosis, proliferation and differentiation. Previous studies have show CaSR induce apoptosis in isolated rat adult heart and in normal rat neonatal cardiomyocytes by G-protein-PLC-IP3 signaling transinduction. A few of studies had demonstrated that CaSR induce apoptosis in cultured neonatal rat cardiomyocytes during ischemia/reperfusion. Hepatocyte growth factor (HGF), as a mesenchymally derived heterodimeric glycoprotein, play vital role in mitogenesis, angiogenesis, cellular motility and growth and anti-apoptosis after postinfarction heart failure via activation of transmembrane tyrosine kinase cell surface receptor c-Met. However, little knowledge exists about whether anti-apoptotic role of HGF in preventing cardiomyocytes injury induced by ischemia/reperfusion is associated with downregulation of CaSR expression. We incubated primary neonatal rat ventricular cardiomyocytes in ischemia-mimetic solution for 2 h, then reincubated them in normal culture medium for 24 h to establish a model of simulated ischemia/reperfusion (I/R). Cardiomyocyte apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. The expression of CaSR mRNA was detected by reverse transcriptase polymerase chain reaction (RT-PCR). In addition, we analyzed the expression of Caspase-3, Bcl-2 and Phosphoinositide 3-kinase (PI3K) by Western blotting. The simulated I/R enhances the expression of CaSR and cardiomyocyte apoptosis. GdCl3, a specific activator of CaSR, further increase the expression of CaSR and Cardiomyocyte apoptosis, along with upregulation of Caspase-3, downregulation of Bcl-2 and inhibiting PI3K phosphorylation. Combination of GdCl3 with LY294002 (a selective PI3K inhibitor) increased Cardiomyocytes apoptosis but did not increased CaSR expression. Treatment of HGF decreased I/R- and GdCl3-induced apoptosis by suppressing Caspase-3 and promoting Bcl-2 and PI3K phosphorylation expression in accordance with downregulation of CaSR expression. HGF exerts protective role in I/R-induced apoptosis at least in part by inhibiting CaSR expression along with promoting Bcl-2, suppressing Caspase-3 expression and stimulating PI3K phosphorylation signaling pathway.
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PMID:Inhibitory effect of hepatocyte growth factor on cardiomyocytes apoptosis is partly related to reduced calcium sensing receptor expression during a model of simulated ischemia/reperfusion. 2108 7


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