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1.  Exogenous H2S contributes to recovery of ischemic post-conditioning-induced cardioprotection by decrease of ROS level via down-regulation of NF-κB and JAK2-STAT3 pathways in the aging cardiomyocytes 
Cell & Bioscience  2016;6:26.
Hydrogen sulfide (H2S), a third member of gasotransmitter family along with nitric oxide and carbon monoxide, generated from mainly catalyzed by cystathionine-lyase, possesses important functions in the cardiovascular system. Ischemic post-conditioning (PC) strongly protects against the hypoxia/reoxygenation (H/R)-induced injury and apoptosis of cardiomyocytes. However, PC protection is ineffective in the aging cardiomyocytes. Whether H2S restores PC-induced cardioprotection by decrease of reactive oxygen species (ROS) level in the aging cardiomyocytes is unknown.
The aging cardiomyocytes were induced by treatment of primary cultures of neonatal cardiomyocytes using d-galactose and were exposed to H/R and PC protocols. Cell viability was observed by CCK-8 kit. Apoptosis was detected by Hoechst 33342 staining and flow cytometry. ROS level was analyzed using spectrofluorimeter. Related protein expressions were detected through Western blot.
Treatment of NaHS (a H2S donor) protected against H/R-induced apoptosis, cell damage, the expression of cleaved caspase-3 and cleaved caspase-9, the release of cytochrome c (Cyt c). The supplementation of NaHS also decreased the activity of LDH and CK, MDA contents, ROS levels and the phosphorylation of IκBα, NF-κB, JNK2 and STAT3, and increased cell viability, the expression of Bcl-2, the activity of SOD, CAT and GSH-PX. PC alone did not provide cardioprotection in H/R-treated aging cardiomyocytes, which was significantly restored by the addition of NaHS. The beneficial role of NaHS was similar to the supply of N-acetyl-cysteine (NAC, an inhibitor of ROS), Ammonium pyrrolidinedithiocarbamate (PDTC, an inhibitor of NF-κB) and AG 490 (an inhibitor of JNK2), respectively, during PC.
Our results suggest that exogenous H2S contributes to recovery of PC-induced cardioprotection by decrease of ROS level via down-regulation of NF-κB and JAK2/STAT3 pathways in the aging cardiomyocytes.
PMCID: PMC4836181  PMID: 27096074
Hydrogen sulfide; Post-conditioning; Oxidative stress; Aging cardiomyocytes
2.  Adsorption of Uranyl ions on Amine-functionalization of MIL-101(Cr) Nanoparticles by a Facile Coordination-based Post-synthetic strategy and X-ray Absorption Spectroscopy Studies 
Scientific Reports  2015;5:13514.
By a facile coordination-based post-synthetic strategy, the high surface area MIL-101(Cr) nanoparticles was functionallized by grafting amine group of ethylenediamine (ED) on coordinatively unsaturated Cr(III) centers, yielding a series of ED-MIL-101(Cr)-based adsorbents and their application for adsorption of U(VI) from aqueous solution were also studied. The obtained ED-functionallized samples with different ED contents were characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), FTIR, elemental analysis (EA) and N2 adsorption and desorption isothermal. Compared with the pristine MIL-101(Cr) sorbents, the ED-functionallized MIL-101(Cr) exhibits significantly higher adsorption capacity for U(VI) ions from water with maximum adsorption capacities as high as 200 mg/g (corresponding to 100% extraction rate) at pH of 4.5 with ED/Cr ratio of 0.68 and the sorbed U(VI) ions can easily be desorbed at lower pH (pH ≤ 2.0). The adsorption mode of U(VI) ions and effects of grafted ED on the MIL-101(Cr) frameworks were also been studied by X-ray absorption spectroscopy (XAS). We believe that this work establishes a simple and energy efficient route to a novel type of functional materials for U(VI) ions extraction from solution via the post-synthetic modification (PSM) strategy.
PMCID: PMC4564734  PMID: 26354407
3.  Exogenous hydrogen sulfide restores cardioprotection of ischemic post-conditioning via inhibition of mPTP opening in the aging cardiomyocytes 
Cell & Bioscience  2015;5:43.
The physiological and pathological roles of hydrogen sulfide (H2S) in the regulation of cardiovascular functions have been recognized. H2S protects against the hypoxia/reoxygenation (H/R)-induced injury and apoptosis of cardiomyocytes, and ischemic post-conditioning (PC) plays an important role in cardioprotection from H/R injury in neonatal cardiomyocytes but not in aging cardiomyocytes. Whether H2S is involved in the recovery of PC-induced cardioprotection in aging cardiomyocytes is unclear. In the present study, we found that both H/R and PC decreased cystathionine-γ-lyase (CSE) expression and the production rate of H2S. Supplementation of NaHS protected against H/R-induced apoptosis, the expression of cleaved caspase-3 and cleaved caspase-9, the release of cytochrome c (Cyt c), and mPTP opening. The addition of NaHS also counteracted the reduction of cell viability caused by H/R and increased the phosphorylation of ERK1/2, PI3K, Akt, GSK-3β and mitochondrial membrane potential. Additionally, NaHS increased Bcl-2 expression, promoted PKC-ε translocation to the cell membrane, and activated mitochondrial ATP-sensitive K channels (mitoKATP). PC alone did not provide cardioprotection in H/R-treated aging cardiomyocytes, which was significantly restored by the supplementation of NaHS. In conclusion, our results suggest that exogenous H2S restores PC-induced cardioprotection via the inhibition of mPTP opening by the activation of the ERK1/2-GSK-3β, PI3K-Akt-GSK-3β and PKC-ε-mitoKATP pathways in aging cardiomyocytes. These findings provide a novel target for the treatment of aging ischemic cardiomyopathy.
Electronic supplementary material
The online version of this article (doi:10.1186/s13578-015-0035-9) contains supplementary material, which is available to authorized users.
PMCID: PMC4520088
Hydrogen sulfide; Post-conditioning; Mitochondrial permeability transition pore; Aging cardiomyocytes
4.  Rhizobia and their bio-partners as novel drivers for functional remediation in contaminated soils 
Environmental pollutants have received considerable attention due to their serious effects on human health. There are physical, chemical, and biological means to remediate pollution; among them, bioremediation has become increasingly popular. The nitrogen-fixing rhizobia are widely distributed in the soil and root ecosystems and can increase legume growth and production by supplying nitrogen, resulting in the reduced need for fertilizer applications. Rhizobia also possess the biochemical and ecological capacity to degrade organic pollutants and are resistant to heavy metals, making them useful for rehabilitating contaminated soils. Moreover, rhizobia stimulate the survival and action of other biodegrading bacteria, thereby lowering the concentration of pollutants. The synergistic action of multiple rhizobial strains enhances both plant growth and the availability of pollutants ranging from heavy metals to persistent organic pollutants. Because phytoremediation has some restrictions, the beneficial interaction between plants and rhizobia provides a promising option for remediation. This review describes recent advances in the exploitation of rhizobia for the rehabilitation of contaminated soil and the biochemical and molecular mechanisms involved, thereby promoting further development of this novel bioremediation strategy into a widely accepted technique.
PMCID: PMC4318275  PMID: 25699064
rhizobia; nitrogen-fixation; bioremediation; organic pollutants; heavy metals; rhizospheric degraders; transgenic rhizobia
5.  A Hybrid Search Algorithm for Swarm Robots Searching in an Unknown Environment 
PLoS ONE  2014;9(11):e111970.
This paper proposes a novel method to improve the efficiency of a swarm of robots searching in an unknown environment. The approach focuses on the process of feeding and individual coordination characteristics inspired by the foraging behavior in nature. A predatory strategy was used for searching; hence, this hybrid approach integrated a random search technique with a dynamic particle swarm optimization (DPSO) search algorithm. If a search robot could not find any target information, it used a random search algorithm for a global search. If the robot found any target information in a region, the DPSO search algorithm was used for a local search. This particle swarm optimization search algorithm is dynamic as all the parameters in the algorithm are refreshed synchronously through a communication mechanism until the robots find the target position, after which, the robots fall back to a random searching mode. Thus, in this searching strategy, the robots alternated between two searching algorithms until the whole area was covered. During the searching process, the robots used a local communication mechanism to share map information and DPSO parameters to reduce the communication burden and overcome hardware limitations. If the search area is very large, search efficiency may be greatly reduced if only one robot searches an entire region given the limited resources available and time constraints. In this research we divided the entire search area into several subregions, selected a target utility function to determine which subregion should be initially searched and thereby reduced the residence time of the target to improve search efficiency.
PMCID: PMC4227730  PMID: 25386855
6.  MRI roadmap-guided transendocardial delivery of exon-skipping recombinant adeno-associated virus restores dystrophin expression in a canine model of Duchenne muscular dystrophy 
Gene therapy  2012;20(3):274-282.
Duchenne muscular dystrophy (DMD) cardiomyopathy patients currently have no therapeutic options. We evaluated catheter-based transendocardial delivery of a recombinant adeno-associated virus (rAAV) expressing a small nuclear U7 RNA (U7smOPT) complementary to specific cis-acting splicing signals. Eliminating specific exons restores the open-reading frame resulting in translation of truncated dystrophin protein. To test this approach in a clinically relevant DMD model, golden retriever muscular dystrophy (GRMD) dogs received serotype 6 rAAV-U7smOPT via the intracoronary or transendocardial route. Transendocardial injections were performed with an injection-tipped catheter and fluoroscopic guidance using X-ray fused with MRI (XFM) roadmaps. Three months after treatment, tissues were analyzed for DNA, RNA, dystrophin protein, and histology. Whereas intracoronary delivery did not result in effective transduction, transendocardial injections, XFM guidance, enabled 30±10 non-overlapping injections per animal. Vector DNA was detectable in all samples tested and ranged from <1 to >3000 vector genome copies per cell. RNA analysis, western blot analysis, and immunohistology demonstrated extensive expression of skipped RNA and dystrophin protein in the treated myocardium. Left ventricular function remained unchanged over a three-month follow-up. These results demonstrated that effective transendocardial delivery of rAAV-U7smOPT was achieved using XFM. This approach restores an open reading frame for dystrophin in affected dogs and has potential clinical utility.
PMCID: PMC3424392  PMID: 22551778
Duchenne muscular dystrophy; rAAV; exon-skipping; cardiomyopathy
7.  Production and Characterization of Novel Recombinant Adeno-Associated Virus Replicative-Form Genomes: A Eukaryotic Source of DNA for Gene Transfer 
PLoS ONE  2013;8(8):e69879.
Conventional non-viral gene transfer uses bacterial plasmid DNA containing antibiotic resistance genes, cis-acting bacterial sequence elements, and prokaryotic methylation patterns that may adversely affect transgene expression and vector stability in vivo. Here, we describe novel replicative forms of a eukaryotic vector DNA that consist solely of an expression cassette flanked by adeno-associated virus (AAV) inverted terminal repeats. Extensive structural analyses revealed that this AAV-derived vector DNA consists of linear, duplex molecules with covalently closed ends (termed closed-ended, linear duplex, or “CELiD”, DNA). CELiD vectors, produced in Sf9 insect cells, require AAV rep gene expression for amplification. Amounts of CELiD DNA produced from insect cell lines stably transfected with an ITR-flanked transgene exceeded 60 mg per 5×109 Sf9 cells, and 1–15 mg from a comparable number of parental Sf9 cells in which the transgene was introduced via recombinant baculovirus infection. In mice, systemically delivered CELiD DNA resulted in long-term, stable transgene expression in the liver. CELiD vectors represent a novel eukaryotic alternative to bacterial plasmid DNA.
PMCID: PMC3731302  PMID: 23936358
8.  Insulin-like growth factor-II mRNA-binding protein 3 predicts a poor prognosis for colorectal adenocarcinoma 
Oncology Letters  2013;6(3):740-744.
Insulin-like growth factor-II mRNA-binding protein 3 (IMP3) has been recently identified as a marker of aggressive behavior in several types of tumors. The aim of the present study was to detect the expression of the IMP3 protein in colorectal adenocarcinoma (CRA) and to identify a correlation with the clinicopathological features of the disease. IMP3 was evaluated in 186 samples of CRA using immunohistochemical methods. The correlation between IMP3 expression and the clinicopathological features of colorectal cancer was evaluated by the χ2 and Fisher’s exact tests. Survival rates were calculated using the Kaplan-Meier method and the correlation between IMP3 protein expression and the prognosis of patients with CRA was analyzed using Cox analysis. Of the 186 adjacent normal mucosa (ANM) cases, the 22 that exhibited dysplasia demonstrated weak IMP3 expression and the 164 without dysplasia showed no expression. Of the 186 CRA cases, immunohistochemical staining for IMP3 was observed in 143 cases (76.9%). A comparison of IMP3 expression between the CRA and ANM samples revealed stronger immunohistochemical reactivity in the CRA tissues (P<0.01). High IMP3 expression was associated with differentiation, lymphoid metastasis, TNM stage, Ki-67 labeling index and a poor patient outcome (P<0.05). In the multivariate analysis, IMP3 emerged as an independent predictor of survival. The present study demonstrated that IMP3 is able to promote the aggressiveness of cancer behavior, resulting in a poor prognosis for patients with CRA. Consequently, IMP3 may be regarded as a novel proliferation and prognostic indicator for patients with CRA.
PMCID: PMC3789059  PMID: 24137402
colorectal adenocarcinoma; insulin-like growth factor-II mRNA-binding protein 3; immunohistochemistry; prognosis
9.  DNA Builds and Strengthens the Extracellular Matrix in Myxococcus xanthus Biofilms by Interacting with Exopolysaccharides 
PLoS ONE  2012;7(12):e51905.
One intriguing discovery in modern microbiology is the extensive presence of extracellular DNA (eDNA) within biofilms of various bacterial species. Although several biological functions have been suggested for eDNA, including involvement in biofilm formation, the detailed mechanism of eDNA integration into biofilm architecture is still poorly understood. In the biofilms formed by Myxococcus xanthus, a Gram-negative soil bacterium with complex morphogenesis and social behaviors, DNA was found within both extracted and native extracellular matrices (ECM). Further examination revealed that these eDNA molecules formed well organized structures that were similar in appearance to the organization of exopolysaccharides (EPS) in ECM. Biochemical and image analyses confirmed that eDNA bound to and colocalized with EPS within the ECM of starvation biofilms and fruiting bodies. In addition, ECM containing eDNA exhibited greater physical strength and biological stress resistance compared to DNase I treated ECM. Taken together, these findings demonstrate that DNA interacts with EPS and strengthens biofilm structures in M. xanthus.
PMCID: PMC3530553  PMID: 23300576
10.  Activating Transcription Factor-2 (ATF2) in survival mechanisms in head and neck carcinoma cells 
Head & neck  2010;33(11):1586-1599.
Activating transcription factor-2 (ATF2) is associated with tumor progression, but is not well-studied in head and neck squamous cell carcinoma (HNSCC). Its effects in stress and its importance in other survival mechanisms were studied.
ATF2 expression and nuclear activation were confirmed in HNSCC. Following modulation of ATF2, in vitro effects on proliferation and chemosensitivity were studied. Effects on in vivo tumor growth and Interleukin 8 (IL-8) expression were determined. Tumor Necrosis Factor (TNF) alpha treatment was used to further evaluate cytokine production and chemosensitivity.
Reductions of ATF2 resulted in significant nuclear p-ATF2 activation, cisplatin resistance and augmented IL-8 expression without affecting in vivo tumor growth. In this setting, TNF increases p-p38 phosphorylation and chemosensitivity while further enhancing IL-8 production.
Our data suggest regulatory roles for ATF2 in TNF-related mechanisms of HNSCC. Its perturbation and nuclear activation are associated with significant effects on survival and cytokine production.
PMCID: PMC3117940  PMID: 21990224
apoptosis; chemoresistance; IL-8; ATF2; cisplatin
11.  Apoptosis Progression in the Hair Cells in the Organ of Corti of GJB2 Conditional Knockout Mice 
Apoptosis may play an important role in the mechanism underlying the GJB2 gene conditional knockout (cCx26) mice cochlear cell death. The objective of this study was to explore the the damage mode of the outer hair cells (OHCs) and its real time point of apoptosis and provide information to further explore the role of apoptosis in the happening of hearing loss in cCx26 mice.
Cochleae from mice at various developmental stages (P8, P12, and P21) were dissected out and first used to be observed under the scanning electron microscope (SEM). Basilar membranes from mice at P8, P14, P18, and P21 were stained by fluorescein isothiocyanate-conjugated phalloidin and propidium iodide (PI) and examined under confocal microscope.
The loss of OHCs of cCx26 knockout mice was first set between P12 and P21 under SEM. Whole mount phalloidin and PI staining revealed that obvious apoptotic appearance of the OHCs surface morphology was observed at P18.
Typical apoptotic morphology was found in the OHCs in the organ of Corti of the cCx26 mice at P18. This may provide information to further study the role of apoptosis in the occurrence of hearing loss of cCx26 mice.
PMCID: PMC3437413  PMID: 22977709
Apoptosis; Outer auditory hair cells; Connexin 26; Sensorineural hearing loss
12.  Use of a Cryptic Splice Site for the Expression of Huntingtin Interacting Protein 1 in Select Normal and Neoplastic Tissues 
Cancer research  2008;68(4):1064-1073.
Huntingtin interacting protein 1 (HIP1) is a 116-kDa endocytic protein, which is necessary for the maintenance of several tissues in vivo as its deficiency leads to degenerative adult phenotypes. HIP1 deficiency also inhibits prostate tumor progression in mice. To better understand how deficiency of HIP1 leads to such phenotypes, we analyzed tumorigenic potential in mice homozygous for a Hip1 mutant allele, designated Hip1Δ3-5, which is predicted to result in a frame-shifted, nonsense mutation in the NH2 terminus of HIP1. In contrast to our previous studies using the Hip1 null allele, an inhibition of tumorigenesis was not observed as a result of the homozygosity of the nonsense Δ3-5 allele. To further examine the contrasting results from the prior Hip1 mutant mice, we cultured tumor cells from homozygous Δ3-5 allele–bearing mice and discovered the presence of a 110-kDa form of HIP1 in tumor cells. Upon sequencing of Hip1 DNA and message from these tumors, we determined that this 110-kDa form of HIP1 is the product of splicing of a cryptic U12-type AT-AC intron. This event results in the insertion of an AG dinucleotide between exons 2 and 6 and restoration of the reading frame. Remarkably, this mutant protein retains its capacity to bind lipids, clathrin, AP2, and epidermal growth factor receptor providing a possible explanation for why tumorigenesis was not altered after this knockout mutation. Our data show how knowledge of the transcript that is produced by a knockout allele can lead to discovery of novel types of molecular compensation at the level of splicing.
PMCID: PMC3135020  PMID: 18281481
13.  Altered Phosphorylation of Cytoskeleton Proteins in Sickle Red Blood Cells: The Role of Protein Kinase C, Rac GTPases, and Reactive Oxygen Species 
The small Rho GTPases Rac1 and Rac2 regulate actin structures and mediate reactive oxygen species (ROS) production via NADPH oxidase in a variety of cells. We have demonstrated that deficiency of Rac1 and Rac2 GTPases in mice disrupts the normal hexagonal organization of the RBC cytoskeleton and reduces erythrocyte deformability. This is associated with increased phosphorylation of adducin at Ser-724, (corresponding to Ser-726 in human erythrocytes), a domain-target of protein kinase C (PKC). PKC phosphorylates adducin and leads to decreased F-actin capping and dissociation of spectrin from actin, implicating a significant role of such phosphorylation in cytoskeletal remodeling. We evaluated adducin phosphorylation in erythrocytes from patients with sickle cell disease and found it consistently increased at Ser-726. In addition, ROS concentration is elevated in sickle erythrocytes by 150–250% compared to erythrocytes from normal control individuals. Here, we review previous studies demonstrating that altered phosphorylation of erythrocyte cytoskeletal proteins and increased ROS production result in disruption of cytoskeleton stability in healthy and sickle cell erythrocytes. We discuss in particular the known and potential roles of protein kinase C and the Rac GTPases in these two processes.
PMCID: PMC2878931  PMID: 20231105
14.  Intranasal Immunization with Recombinant HA and Mast Cell Activator C48/80 Elicits Protective Immunity against 2009 Pandemic H1N1 Influenza in Mice 
PLoS ONE  2011;6(5):e19863.
Pandemic influenza represents a major threat to global health. Vaccination is the most economic and effective strategy to control influenza pandemic. Conventional vaccine approach, despite being effective, has a number of major deficiencies including limited range of protection, total dependence on embryonated eggs for production, and time consuming for vaccine production. There is an urgent need to develop novel vaccine strategies to overcome these deficiencies.
Methodology/Principal Findings
The major objective of this work was to develop a novel vaccine strategy combining recombinant haemagglutinin (HA) protein and a master cell (MC) activator C48/80 for intranasal immunization. We demonstrated in BALB/c mice that MC activator C48/80 had strong adjuvant activity when co-administered with recombinant HA protein intranasally. Vaccination with C48/80 significantly increased the serum IgG and mucosal surface IgA antibody responses against HA protein. Such increases correlated with stronger and durable neutralizing antibody activities, offering protection to vaccinated animals from disease progression after challenge with lethal dose of A/California/04/2009 live virus. Furthermore, protected animals demonstrated significant reduction in lung virus titers, minimal structural alteration in lung tissues as well as higher and balanced production of Th1 and Th2 cytokines in the stimulated splenocytes when compared to those without C48/80.
The present study demonstrates that the novel vaccine approach of combining recombinant HA and mucosal adjuvant C48/80 is safe and effective in eliciting protective immunity in mice. Future studies on the mechanism of action of C48/80 and potential combination with other vaccine strategies such as prime and boost approach may help to induce even more potent and broad immune responses against viruses from various clades.
PMCID: PMC3098841  PMID: 21625486
15.  Design and Characterization of an Acid-Activated Antimicrobial Peptide 
Chemical biology & drug design  2009;75(1):127-132.
Dental caries is a microbial biofilm infection in which the metabolic activities of plaque bacteria result in a dramatic pH decrease and shift the demineralization/ remineralization equilibrium on the tooth surface towards demineralization. In addition to causing a net loss in tooth minerals creation of an acidic environment favors growth of acid enduring and acid generating species, which causes further reduction in the plaque pH. In this study we developed a prototype antimicrobial peptide capable of achieving high activity exclusively at low environmental pH to target bacterial species like Streptococcus mutans that produce acid and thrive under the low pH conditions detrimental for tooth integrity. The features of clavanin A, a naturally occurring peptide rich in histidine and phenylalanine residues with pH-dependent antimicrobial activity, served as a design basis for these prototype “acid-activated peptides” (AAPs). Employing the major cariogenic species S. mutans as a model system, the two AAPs characterized in this study exhibited a striking pH-dependent antimicrobial activity which correlated well with the calculated charge distribution. This type of peptide represents a potential new way to combat dental caries.
PMCID: PMC2790279  PMID: 19878192
Targeted antimicrobial therapy; pH dependent antimicrobial activity; biofilm; Streptococcus mutans
16.  Persistence of Leukemia-Initiating Cells in a Conditional Knockin Model of an Imatinib-Responsive Myeloproliferative Disorder 
Cancer cell  2009;16(2):137-148.
Despite remarkable responses to the tyrosine kinase inhibitor imatinib, CML patients are rarely cured by this therapy perhaps due to imatinib-refractoriness of leukemia-initiating cells (LICs). Evidence for this is limited because of poor engraftment of human CMLLICs in NOD-SCID mice and non-physiologic expression of oncogenes in retroviral transduction mouse models. To address these challenges, we generated mice bearing conditional knockin alleles of two human oncogenes: HIP1/PDGFβR (H/P) and AML1-ETO (A/E). Unlike retroviral transduction, physiologic expression of H/P or A/E individually failed to induce disease, but co-expression of both H/P and A/E led to rapid onset of a fully penetrant, myeloproliferative disorder (MPD), indicating cooperativity between these two alleles. Although imatinib dramatically decreased disease burden, LICs persisted, demonstrating imatinib-refractoriness of LICs.
PMCID: PMC2763369  PMID: 19647224
17.  Abundance Changes of the Response Regulator RcaC Require Specific Aspartate and Histidine Residues and Are Necessary for Normal Light Color Responsiveness▿  
Journal of Bacteriology  2008;190(21):7241-7250.
RcaC is a large, complex response regulator that controls transcriptional responses to changes in ambient light color in the cyanobacterium Fremyella diplosiphon. The regulation of RcaC activity has been shown previously to require aspartate 51 and histidine 316, which appear to be phosphorylation sites that control the DNA binding activity of RcaC. All available data suggest that during growth in red light, RcaC is phosphorylated and has relatively high DNA binding activity, while during growth in green light RcaC is not phosphorylated and has less DNA binding activity. RcaC has also been found to be approximately sixfold more abundant in red light than in green light. Here we demonstrate that the light-controlled abundance changes of RcaC are necessary, but not sufficient, to direct normal light color responses. RcaC abundance changes are regulated at both the RNA and protein levels. The RcaC protein is significantly less stable in green light than in red light, suggesting that the abundance of this response regulator is controlled at least in part by light color-dependent proteolysis. We provide evidence that the regulation of RcaC abundance does not depend on any RcaC-controlled process but rather depends on the presence of the aspartate 51 and histidine 316 residues that have previously been shown to control the activity of this protein. We propose that the combination of RcaC abundance changes and modification of RcaC by phosphorylation may be necessary to provide the dynamic range required for transcriptional control of RcaC-regulated genes.
PMCID: PMC2580696  PMID: 18757544
18.  Differential display identifies overexpression of the USP36 gene, encoding a deubiquitinating enzyme, in ovarian cancer 
Objectives. To find potential diagnostic markers or therapeutic targets, we used differential display technique to identify genes that are over or under expressed in human ovarian cancer.
Methods. Genes were initially identified by differential display between two human ovarian surface epithelium cultures and two ovarian cancer cell lines, A2780 and Caov-3. Genes were validated by relative quantitative RT-PCR and RNA in situ hybridization.
Results. Twenty-eight non-redundant sequences were expressed differentially in the normal ovarian epithelium and ovarian cancer cell lines. Seven of the 28 sequences showed differential expression between normal ovary and ovarian cancer tissue by RT-PCR. USP36 was over-expressed in ovarian cancer cell lines and tissues by RT-PCR and RNA in situ hybridization. Northern blot analysis and RT-PCR revealed two transcripts for USP36 in ovarian tissue. The major transcript was more specific for ovarian cancer and was detected by RT-PCR in 9/9 ovarian cancer tissues, 3/3 cancerous ascites, 5/14 (36%) sera from patients with ovarian cancer, and 0/7 sera from women without ovarian cancer.
Conclusion. USP36 is overexpressed in ovarian cancer compared to normal ovary and its transcripts were identified in ascites and serum of ovarian cancer patients.
PMCID: PMC2424181  PMID: 18566677
ovarian cancer; biological markers; ubiquitin specific peptidase 36 (USP36); deubiquitinating enzyme
19.  Molecular cloning, expression and pharmacological characterization of the canine cholecystokinin 1 receptor 
British Journal of Pharmacology  2005;145(3):374-384.
The full-length, canine cholecystokinin 1 (CCK1) receptor was cloned from gallbladder tissue using RT–PCR with a combination of primers designed to interact with conserved regions of the human and rat CCK1 receptor, which also shared homology with the canine genomic sequence.Analysis of the sequence of the canine CCK1 receptor revealed a 1287 base pair product, which encoded a 429 amino-acid protein. This protein was 89% identical to the human and 85% identical to the rat CCK1 receptor.The canine CCK1 receptor was expressed in CHO-K cells for pharmacological characterization. In competition studies, using [125I]BH-CCK-8S as radioligand, the affinity values estimated for CCK receptor-selective compounds were not significantly different between the canine and human CCK1 receptors (pKI±s.e.m. at canine CCK1 receptor; L-364,718=8.82±0.08, L-365,260=6.61±0.05, YF476=7.91±0.15, YM022=8.28±0.06 and dexloxiglumide=7.53±0.11). Furthermore, the selectivity of these compounds between canine CCK1 and CCK2 receptors was consistent with the selectivity between the human CCK1 and CCK2 receptors.Two additional forms of the canine CCK1 receptor were identified during the cloning procedure. These had three (variant #1) and six (variant #2) amino-acid differences from the wild-type canine CCK1 receptor. Variant #1 bound [125I]BH-CCK-8S and displayed an identical pharmacological profile to the wild-type receptor using the ligands described above. No significant binding was measured with variant #2.In conclusion, we have cloned and pharmacologically characterized the canine CCK1 receptor. The data obtained will facilitate the interpretation of numerous pharmacological experiments that have been performed using canine tissue to elucidate the actions of CCK and gastrin.
PMCID: PMC1576148  PMID: 15765098
Cholecystokinin; CCK1 receptor; CCKA receptor; L-364,718; L-365,260; YF476; YM022; dexloxiglumide
20.  Hip1-related Mutant Mice Grow and Develop Normally but Have Accelerated Spinal Abnormalities and Dwarfism in the Absence of HIP1† 
Molecular and Cellular Biology  2004;24(10):4329-4340.
In mice and humans, there are two known members of the Huntingtin interacting protein 1 (HIP1) family, HIP1 and HIP1-related (HIP1r). Based on structural and functional data, these proteins participate in the clathrin trafficking network. The inactivation of Hip1 in mice leads to spinal, hematopoietic, and testicular defects. To investigate the biological function of HIP1r, we generated a Hip1r mutant allele in mice. Hip1r homozygous mutant mice are viable and fertile without obvious morphological abnormalities. In addition, embryonic fibroblasts derived from these mice do not have gross abnormalities in survival, proliferation, or clathrin trafficking pathways. Altogether, this demonstrates that HIP1r is not necessary for normal development of the embryo or for normal adulthood and suggests that HIP1 or other functionally related members of the clathrin trafficking network can compensate for HIP1r absence. To test the latter, we generated mice deficient in both HIP1 and HIP1r. These mice have accelerated development of abnormalities seen in Hip1 -deficient mice, including kypholordosis and growth defects. The severity of the Hip1r/Hip1 double-knockout phenotype compared to the Hip1 knockout indicates that HIP1r partially compensates for HIP1 function in the absence of HIP1 expression, providing strong evidence that HIP1 and HIP1r have overlapping roles in vivo.
PMCID: PMC400480  PMID: 15121852
21.  The C-terminal domain of Escherichia coli MutY is involved in DNA binding and glycosylase activities 
Nucleic Acids Research  2003;31(12):3038-3049.
Escherichia coli MutY is an adenine and a weak guanine DNA glycosylase involved in reducing mutagenic effects of 7,8-dihydro-8-oxo-guanine (8-oxoG). The C-terminal domain of MutY is required for 8-oxoG recognition and is critical for mutation avoidance of oxidative damage. To determine which residues of this domain are involved in 8-oxoG recognition, we constructed four MutY mutants based on similarities to MutT, which hydrolyzes specifically 8-oxo-dGTP to 8-oxo-dGMP. F294A-MutY has a slightly reduced binding affinity to A/G mismatch but has a severe defect in A/8-oxoG binding at 20°C. The catalytic activity of F294A-MutY is much weaker than that of the wild-type MutY. The DNA binding activity of R249A-MutY is comparable to that of the wild-type enzyme but the catalytic activity is reduced with both A/G and A/8-oxoG mismatches. The biochemical activities of F261A-MutY are nearly similar to those of the wild-type enzyme. The solubility of P262A-MutY was improved as a fusion protein containing streptococcal protein G (GB1 domain) at its N-terminus. The binding of GB1-P262A-MutY with both A/G and A/8-oxoG mismatches are slightly weaker than those of the wild-type protein. The catalytic activity of GB1-P262A-MutY is weaker than that of the wild-type enzyme at lower enzyme concentrations. Importantly, all four mutants can complement mutY mutants in vivo when expressed at high levels; however, F294A, R249A and P262A, but not F261A, are partially defective in vivo when they are expressed at low levels. These results strongly support that the C-terminal domain of MutY is involved not only in 8-oxoG recognition, but also affects the binding and catalytic activities toward A/G mismatches.
PMCID: PMC162338  PMID: 12799430
22.  Extremely Barophilic Bacteria Isolated from the Mariana Trench, Challenger Deep, at a Depth of 11,000 Meters 
Two strains of obligately barophilic bacteria were isolated from a sample of the world’s deepest sediment, which was obtained by the unmanned deep-sea submersible Kaiko in the Mariana Trench, Challenger Deep, at a depth of 10,898 m. From the results of phylogenetic analysis based on 16S rRNA gene sequences, DNA-DNA relatedness study, and analysis of fatty acid composition, the first strain (DB21MT-2) appears to be most highly similar to Shewanella benthica and close relatives, and the second strain (DB21MT-5) appears to be closely related to the genus Moritella. The optimal pressure conditions for growth of these isolates were 70 MPa for strain DB21MT-2 and 80 MPa for strain DB21MT-5, and no growth was detected at pressures of less than 50 MPa with either strain. This is the first evidence of the existence of an extreme-barophile bacterium of the genus Moritella isolated from the deep-sea environment.
PMCID: PMC106178  PMID: 9546187

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