bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic Characterization ofPseudomonas fluorescensSBW25rspGene Expression in the Phytosphere and In Vitro
Authors: Jackson Robert W. , Preston Gail M. , Rainey Paul B. 
Published: December 2005

ABSTRACTThe plant-colonizingPseudomonas fluorescensstrain SBW25 harbors a gene cluster (rsp) whose products show similarity to type III protein secretion systems found in plant and animal pathogens. Here we report a detailed analysis of the expression and regulation of theP. fluorescens rsppathway, both in the phytosphere and in vitro. A combination of chromosomally integrated transcriptional reporter fusions, overexpressed regulatory genes, and specific mutants reveal that promoters controlling expression ofrspare actively transcribed in the plant rhizosphere but not (with the exception of therspCpromoter) in the phyllosphere. In synthetic medium, regulatory (rspLandrspR) and structural (rspU, plus the putative effectorropE) genes are poorly expressed; therspCpromoter is subject to an additional level of regulatory control. Ectopic expression of regulatory genes in wild-type and mutant backgrounds showed that RspR controls transcription of the alternate sigma factor,rspL, and that RspL controls expression of gene clusters encoding structural genes. Mutation ofrspVdid not affect RspR-mediated expression ofrspU. A search for additional regulators revealed two candidates—one with a role in the conversion of alanine to pyruvate—suggesting that expression ofrspis partly dependent upon the metabolic status of the cell. Mutations inrspregulators resulted in a significant reduction in competitive colonization of the root tips of sugar beet seedlings but also caused a marked increase in the lag phase of laboratory-grown cultures, indicating thatrspregulatory genes play a more significant general role in the function ofP. fluorescensSBW25 than previously appreciated.
FpvA-Mediated Ferric Pyoverdine Uptake in
Pseudomonas aeruginosa:
Identification of Aromatic Residues in FpvA Implicated in Ferric Pyoverdine Binding and Transport
Authors: Shen Jiang-Sheng , Geoffroy Valérie , Neshat Shadi , Jia Zongchao , Meldrum Allison , Meyer Jean-Marie , Poole Keith 
Published: December 2005

ABSTRACT

A number of aromatic residues were seen to cluster in the upper portion of the three-dimensional structure of the FpvA ferric pyoverdine receptor of
Pseudomonas aeruginosa
, reminiscent of the aromatic binding pocket for ferrichrome in the FhuA receptor of
Escherichia coli
. Alanine substitutions in three of these, W362, W391, and F795, markedly compromised ferric pyoverdine binding and transport, consistent with a role of FpvA in ferric pyoverdine recognition.
SigF, a New Sigma Factor Required for a Motility System of
Myxococcus xanthus
Authors: Ueki Toshiyuki , Xu Chun-Ying , Inouye Sumiko 
Published: December 2005

ABSTRACT

A new sigma factor, SigF, was identified from the social and developmental bacterium
Myxococcus xanthus
. SigF is required for fruiting body formation during development as well as social motility during vegetative growth. Analysis of gene expression indicates that it is possible that the
sigF
gene is involved in regulation of an unidentified gene for social motility.
ON THE WEAK-COUPLING LIMIT FOR BOSONS AND FERMIONS
Authors: BENEDETTO D. , PULVIRENTI M. , CASTELLA F. , ESPOSITO R. 
Published: December 2005

In this paper we consider a large system of bosons or fermions. We start with an initial datum which is compatible with the Bose–Einstein, respectively Fermi–Dirac, statistics. We let the system of interacting particles evolve in a weak-coupling regime. We show that, in the limit, and up to the second order in the potential, the perturbative expansion expressing the value of the one-particle Wigner function at time t, agrees with the analogous expansion for the solution to the Uehling–Uhlenbeck equation. This paper follows the same spirit as the companion work,2 where the authors investigated the weak-coupling limit for particles obeying the Maxwell–Boltzmann statistics: here, they proved a (much stronger) convergence result towards the solution of the Boltzmann equation.
Carcinoembryonic Antigen–Related Cell Adhesion Molecule 1a-4L Suppression of Rat Hepatocellular Carcinomas
Authors: Laurie Nikia A. , Comegys Meghan M. , Carreiro Marie P. , Brown Jeanne F. , Flanagan Donna L. , Brilliant Kate E. , Hixson Douglas C. 
Published: December 2005

Abstract
Carcinoembryonic antigen (CEA)–related cell adhesion molecule 1 (CEACAM1) is a member of the CEA family of immunoglobulin-like adhesion molecules with two major splice variants, CEACAM1a-4L and CEACAM1b-4S, differing in the length of their COOH-terminal cytoplasmic tail. Both forms are down-regulated in prostate and liver carcinomas relative to normal tissues. We have previously shown in a nude mouse xenograft model that restoration of CEACAM1a-4L expression in human prostate carcinoma cells (PC-3) suppresses tumorigenicity, an effect observed with carcinomas from several other tissues but never established for hepatocellular carcinomas. In this report, we have examined the effect of CEACAM1a-4L on tumorigenicity of 1682A, a rat hepatocellular carcinoma that grows on the omentum when injected into the peritoneal cavity. Results show that restoration of CEACAM1a-4L expression at levels 13- and 0.45-fold compared with negative controls or normal hepatocytes, respectively, completely suppressed the formation of 1682A tumor nodules on the omentum at 3 weeks after injection. In contrast, 1682A cells infected with CEACAM1b-4S or an empty retroviral vector formed multiple clusters of tumor nodules. Although tumor nodules of 1682A cells positive and negative for CEACAM1a-4L did not display significant differences in histologic organization, aggregates formed in vitro by 1682A-L were smaller in size and displayed enlarged intercellular spaces relative to their 1682A-V counterparts. Restoration of CEACAM1a-4L expression did not elevate levels of apoptosis but seemed to cause an increase in the length of G1. This is the first demonstration of CEACAM1a-4L–induced tumor suppression in liver carcinomas using a quantifiable i.p. syngeneic transplantation model.
Phosphorylation of Galectin-3 Contributes to Malignant Transformation of Human Epithelial Cells via Modulation of Unique Sets of Genes
Authors: Mazurek Nachman , Sun Yun Jie , Price Janet E. , Ramdas Latha , Schober Wendy , Nangia-Makker Pratima , Byrd James C. , Raz Avraham , Bresalier Robert S. 
Published: December 2005

Abstract
Galectin-3 is a multifunctional β-galactoside-binding protein implicated in apoptosis, malignant transformation, and tumor progression. The mechanisms by which galectin-3 contributes to malignant progression are not fully understood. In this study, we found that the introduction of wild-type galectin-3 into nontumorigenic, galectin-3-null BT549 human breast epithelial cells conferred tumorigenicity and metastatic potential in nude mice, and that galectin-3 expressed by the cells was phosphorylated. In contrast, BT549 cells expressing galectin-3 incapable of being phosphorylated (Ser6→Glu Ser6→Ala) were nontumorigenic. A microarray analysis of 10,000 human genes, comparing BT549 transfectants expressing wild-type and those expressing phosphomutant galectin-3, identified 188 genes that were differentially expressed (&gt;2.5-fold). Genes affected by introduction of wild-type phosphorylated but not phosphomutant galectin-3 included those involved in oxidative stress, a novel noncaspase lysosomal apoptotic pathway, cell cycle regulation, transcriptional activation, cytoskeleton remodeling, cell adhesion, and tumor invasion. The reliability of the microarray data was validated by real-time reverse transcription-PCR (RT-PCR) and by Western blot analysis, and clinical relevance was evaluated by real-time RT-PCR screening of a panel of matched pairs of breast tumors. Differentially regulated genes in breast cancers that are also predicted to be associated with phospho-galectin-3 in transformed BT549 cells include C-type lectin 2, insulin-like growth factor-binding protein 5, cathepsins L2, and cyclin D1. These data show the functional diversity of galectin-3 and suggest that phosphorylation of the protein is necessary for regulation (directly or indirectly) of unique sets of genes that play a role in malignant transformation.
E1AF/PEA3 Activates the Rho/Rho-Associated Kinase Pathway to Increase the Malignancy Potential of Non–Small-Cell Lung Cancer Cells
Authors: Hakuma Nobuyuki , Kinoshita Ichiro , Shimizu Yasushi , Yamazaki Koichi , Yoshida Koichi , Nishimura Masaharu , Dosaka-Akita Hirotoshi 
Published: December 2005

Abstract
E1AF/PEA3, an Ets family transcription factor, is frequently overexpressed in non–small-cell lung cancers (NSCLCs). Overexpression of E1AF increases motility and invasion of VMRC-LCD and NCI-H226 NSCLC cells, which lack endogenous E1AF expression, and the effect is synergistically increased by hepatocyte growth factor (HGF). The small GTPase Rho/Rho-associated kinase (ROCK) pathway is also involved in motility and invasion. To determine the role of the Rho/ROCK pathway in malignant phenotypes induced by E1AF, we analyzed VMRC-LCD cells transfected with an E1AF expression vector (LCD-E1AF cells) or with empty vector (LCD-vector cells). LCD-E1AF cells had more GTP-bound (active) Rho than LCD-vector cells and Rho activation was synergistically increased by HGF. The Rho activation by E1AF and HGF was also shown in NCI-H226 cells. Phosphorylation of myosin light chain (MLC), a downstream effector of ROCK signaling, was higher in LCD-E1AF cells than in LCD-vector cells, especially under HGF treatment. A specific ROCK inhibitor, Y27632, strongly suppressed MLC phosphorylation, cell motility, and invasion. In nude mice implanted s.c. and intrapulmonarily, LCD-E1AF cells made more local tumors than LCD-vector cells (six of six versus one of seven mice and four of seven versus one of seven mice, respectively). Three of the four mice with lung tumors from LCD-E1AF cells had lymph node metastases whereas the mouse with LCD-vector tumors did not. LCD-E1AF tumors showed higher MLC phosphorylation than LCD-vector tumors. These results suggest that E1AF activates the Rho/ROCK pathway in an HGF-enhanced manner and its activation is important in E1AF-induced motility and invasion as well as tumorigenesis and metastasis in NSCLC cells.
Targeting PBR by Hexaminolevulinate-Mediated Photodynamic Therapy Induces Apoptosis through Translocation of Apoptosis-Inducing Factor in Human Leukemia Cells
Authors: Furre Ingegerd Eggen , Shahzidi Susan , Luksiene Zivile , Møller Michael T.N. , Borgen Elin , Morgan Janet , Tkacz-Stachowska Kinga , Nesland Jahn M. , Peng Qian 
Published: December 2005

Abstract
Photodynamic therapy (PDT) with endogenous protoporphyrin IX derived from 5-aminolevulinic acid or its derivatives has been established for treatments of several premalignancies and malignancies; however, the mechanism of the modality is not fully elucidated. The mitochondrial permeability transition pore consists mainly of the mitochondrial outer membrane voltage-dependent anion channel and the peripheral benzodiazepine receptor (PBR) and the mitochondrial inner membrane adenine nucleotide translocator (ANT). These mitochondrial proteins are responsible for the permeability transition that leads to apoptosis. In the present study, the human leukemia cell line, Reh, was treated with PDT using hexaminolevulinate (HAL). More than 80% of apoptotic Reh cells were found after HAL-mediated PDT (HAL-PDT) with high-molecular-weight (50 kbp) DNA fragmentation. Addition of PK11195 or Ro5-4864, two ligands of PBR, during HAL-PDT significantly inhibited the apoptotic effect. Bongkrekic acid, a ligand for ANT, also reduced the PDT effect. Although the mitochondrial transmembrane potential collapsed, neither cytosolic translocation of mitochondrial cytochrome c nor activation of caspase-9, caspase-8, caspase-3, and poly(ADP-ribose) polymerase were found. However, nuclear translocation of mitochondrial apoptosis-inducing factor (AIF) was shown by both immunoblotting and immunocytochemistry. Because AIF is the sole one among all proapoptotic factors involved in caspase-dependent and caspase-independent pathways that induces the high-molecular-weight DNA fragmentation, we conclude that HAL-PDT specifically targets PBR, leading to apoptosis of the Reh cells through nuclear translocation of mitochondrial AIF. This study suggests PBR as a possible novel therapeutic target for HAL-based PDT of cancer.
Evidence for the Direct Binding of Phosphorylated p53 to Sites of DNA Breaks In vivo
Authors: Al Rashid Shahnaz T. , Dellaire Graham , Cuddihy Andrew , Jalali Farid , Vaid Mita , Coackley Carla , Folkard Melvyn , Xu Yang , Chen Benjamin P.C. , Chen David J. , Lilge Lothar , Prise Kevin M. , Bazett Jones David P. , Bristow Robert G. 
Published: December 2005

Abstract
Despite a clear link between ataxia-telangiectasia mutated (ATM)–dependent phosphorylation of p53 and cell cycle checkpoint control, the intracellular biology and subcellular localization of p53 phosphoforms during the initial sensing of DNA damage is poorly understood. Using G0-G1 confluent primary human diploid fibroblast cultures, we show that endogenous p53, phosphorylated at Ser15 (p53Ser15), accumulates as discrete, dose-dependent and chromatin-bound foci within 30 minutes following induction of DNA breaks or DNA base damage. This biologically distinct subpool of p53Ser15 is ATM dependent and resistant to 26S-proteasomal degradation. p53Ser15 colocalizes and coimmunoprecipitates with γ-H2AX with kinetics similar to that of biochemical DNA double-strand break (DNA-dsb) rejoining. Subnuclear microbeam irradiation studies confirm p53Ser15 is recruited to sites of DNA damage containing γ-H2AX, ATMSer1981, and DNA-PKcsThr2609 in vivo. Furthermore, studies using isogenic human and murine cells, which express Ser15 or Ser18 phosphomutant proteins, respectively, show defective nuclear foci formation, decreased induction of p21WAF, decreased γ-H2AX association, and altered DNA-dsb kinetics following DNA damage. Our results suggest a unique biology for this p53 phosphoform in the initial steps of DNA damage signaling and implicates ATM-p53 chromatin-based interactions as mediators of cell cycle checkpoint control and DNA repair to prevent carcinogenesis.
Effects of VHL Deficiency on Endolymphatic Duct and Sac
Authors: Gläsker Sven , Lonser Russell R. , Tran Maxine G.B. , Ikejiri Barbara , Butman John A. , Zeng Weifen , Maxwell Patrick H. , Zhuang Zhengping , Oldfield Edward H. , Vortmeyer Alexander O. 
Published: December 2005

Abstract
The von Hippel-Lindau (VHL) disease is caused by VHL germ line mutation. Inactivation of the wild-type copy of the VHL gene leads to up-regulation of hypoxic response and tumor formation within central nervous system (CNS), kidneys, pancreas, adrenal glands, epididymis, broad ligament, and the endolymphatic sac/petrous bone. Endolymphatic sac tumors (ELST) have been proposed to be derived from endolymphatic sac epithelium, but other possible structures of origin have been implicated. To clarify the anatomic and cellular origin of ELSTs, we did a morphologic and molecular pathologic analysis of 16 tumors. In addition, we investigated effects of VHL deficiency on “tumor-free” endolymphatic duct and sac of VHL patients. Several tumors included in this study were &lt;1 cm in size, and their origin could be placed in the intraosseous portion of the endolymphatic duct/sac. Furthermore, by analysis of clinically uninvolved “tumor-free” endolymphatic duct and sac tissues of VHL patients, we discovered a variety of VHL-deficient microscopic abnormalities with morphologic similarities to ELSTs. We conclude that most, if not all, ELSTs arise within the intraosseous portion of the endolymphatic duct/sac, the vestibular aqueduct. In analogy to renal parenchyma and selected topographical sites within the CNS, endolymphatic duct/sac epithelia are preferentially and multifocally targeted in VHL disease. The primary effect of VHL deficiency on human endolymphatic duct/sac epithelium seems to be the generation of multifocal sites of VHL-deficient cell proliferations from which tumorigenesis may or may not occur. Therefore, inactivation of the VHL wild-type allele seems necessary but not sufficient for the formation of tumor.
Hypoxia-Induced Phosphorylation of Chk2 in an Ataxia Telangiectasia Mutated–Dependent Manner
Authors: Gibson Shannon L. , Bindra Ranjit S. , Glazer Peter M. 
Published: December 2005

Abstract
Chk2 is a serine/threonine kinase that signals to cell cycle arrest, DNA repair, and apoptotic pathways following DNA damage. It is activated by phosphorylation in response to ionizing radiation, UV light, stalled replication forks, and other types of DNA damage. Hypoxia is a common feature of solid tumors and has been shown to affect the regulation of many genes, including several DNA repair factors. We show here that Chk2 is phosphorylated on Thr68 and thereby activated in cells in response to hypoxia, and that this phosphorylation is dependent on the damage response kinase ataxia telangiectasia mutated (ATM) but not on the related kinase ATM and Rad3-related. Moreover, phosphorylation of Chk2 under hypoxia was attenuated in cells deficient in the repair factors MLH1 or NBS1. Finally, Chk2 serves to protect cells from apoptosis under hypoxic growth conditions. These results identify hypoxia as a new stimulus for Chk2 activation in an ATM-, MLH1-, and NBS1-dependent manner, and they suggest a novel pathway by which tumor hypoxia may influence cell survival and DNA repair.
Cyclin E Both Regulates and Is Regulated by Calpain 2, a Protease Associated with Metastatic Breast Cancer Phenotype
Authors: Libertini Stephen J. , Robinson Brian S. , Dhillon Navdeep K. , Glick Danielle , George Michael , Dandekar Satya , Gregg Jeffrey P. , Sawai Earl , Mudryj Maria 
Published: December 2005

AbstractOverexpression of cyclin E in breast tumors is associated with a poor response to tamoxifen therapy, greater genomic instability, more aggressive behavior, and a poor clinical prognosis. These tumors also express low molecular weight isoforms of cyclin E that are associated with higher kinase activity and increased metastatic potential. In the current study, we show that cyclin E overexpression in MCF7 cells transactivates the expression of calpain 2, leading to proteolysis of cyclin E as well as several known calpain substrates including focal adhesion kinase (FAK), calpastatin, pp60src, and p53. In vivo inhibition of calpain activity in MCF7-cyclin E cells impedes cyclin E proteolysis, whereas in vivo induction of calpain activity promotes cyclin E proteolysis. An analysis of human breast tumors shows that high levels of cyclin E are coincident with the expression of the low molecular weight isoforms, high levels of calpain 2 protein, and proteolysis of FAK. Lastly, studies using a mouse model of metastasis reveal that highly metastatic tumors express proteolyzed cyclin E and FAK when compared to tumors with a low metastatic potential. Our results suggest that cyclin E–dependent deregulation of calpain may be pivotal in modifying multiple cellular processes that are instrumental in the etiology and progression of breast cancer.
Persistent Organochlorine Chemicals in Plasma and Risk of Non-Hodgkin's Lymphoma
Authors: De Roos Anneclaire J. , Hartge Patricia , Lubin Jay H. , Colt Joanne S. , Davis Scott , Cerhan James R. , Severson Richard K. , Cozen Wendy , Patterson Donald G. , Needham Larry L. , Rothman Nathaniel 
Published: December 2005

Abstract
Polychlorinated biphenyls (PCB) have been suspected as possible contributors to increasing non-Hodgkin's lymphoma incidence during the latter half of the 20th century based on their toxicologic properties and provocative epidemiologic reports. We investigated PCBs and other organochlorines and risk of non-Hodgkin's lymphoma in a population-based case-control study in the United States. Congeners of PCBs (including coplanar congeners), dioxins, furans and pesticides or pesticide metabolites were measured in plasma of 100 untreated cases and 100 control subjects. We used a multiple imputation procedure to fill in missing values of levels determined to be below the detection limits. Risks of non-Hodgkin's lymphoma associated with each analyte were estimated using conditional logistic regression for the continuous measure, exposure quartiles, trend across quartile categories, and exposures above the 95th percentile. Certain PCB congeners were associated with increased risk of non-Hodgkin's lymphoma, including coplanar PCBs 156, 180, and 194, with odds ratios for the highest versus lowest quartile ranging from 2.7 to 3.5, and significant trends. Each of the furan congeners was associated with risk of non-Hodgkin's lymphoma, as were total furans, with 3.5-fold increased risk for the highest versus lowest quartile and a significant trend across quartiles (P = 0.006). The toxic equivalency quotient (TEQ), a summed metric that weights congeners by their dioxin-like potency, was associated with non-Hodgkin's lymphoma, with 35% increased risk per 10 TEQ pg/g lipid (95% confidence interval, 1.02-1.79). Our results add to existing literature, which suggests that exposure to organochlorines contributes to non-Hodgkin's lymphoma risk; these risks were most apparent for certain PCBs and furans.
Vascular Endothelial Growth Factor Contributes to Prostate Cancer–Mediated Osteoblastic Activity
Authors: Kitagawa Yasuhide , Dai Jinlu , Zhang Jian , Keller Jill M. , Nor Jacques , Yao Zhi , Keller Evan T. 
Published: December 2005

Abstract
Prostate cancer frequently metastasizes to bone resulting in the formation of osteoblastic metastases through unknown mechanisms. Vascular endothelial growth factor (VEGF) has been shown recently to promote osteoblast activity. Accordingly, we tested if VEGF contributes to the ability of prostate cancer to induce osteoblast activity. PC-3, LNCaP, and C4-2B prostate cancer cell lines expressed both VEGF-165 and VEGF-189 mRNA isoforms and VEGF protein. Prostate cancer cells expressed the mRNA for VEGF receptor (VEGFR) neuropilin-1 but not the VEGFRs Flt-1 or KDR. In contrast, mouse pre-osteoblastic cells (MC3T3-E1) expressed Flt-1 and neuropilin-1 mRNA but not KDR. PTK787, a VEGFR tyrosine kinase inhibitor, inhibited the proliferation of human microvascular endothelial cells but not prostate cancer proliferation in vitro. C4-2B conditioned medium induced osteoblast differentiation as measured by production of alkaline phosphatase and osteocalcin and mineralization of MC3T3-E1. PTK787 blocked the C4-2B conditioned medium–induced osteoblastic activity. VEGF directly induced alkaline phosphatase and osteocalcin but not mineralization of MC3T3-E1. These results suggest that VEGF induces initial differentiation of osteoblasts but requires other factors, present in C4-2B, to induce mineralization. To determine if VEGF influences the ability of prostate cancer to develop osteoblastic lesions, we injected C4-2B cells into the tibia of mice and, after the tumors grew for 6 weeks, administered PTK787 for 4 weeks. PTK787 decreased both intratibial tumor burden and C4-2B–induced osteoblastic activity as measured by bone mineral density and serum osteocalcin. These results show that VEGF contributes to prostate cancer–induced osteoblastic activity in vivo.