bluuebunny/crossref_metadata_2025_split huggingface dataset:
Related assemblages of sulphate‐reducing bacteria associated with ultradeep gold mines of South Africa and deep basalt aquifers of Washington State
Authors: Baker Brett J. , Moser Duane P. , MacGregor Barbara J. , Fishbain Susan , Wagner Michael , Fry Norman K. , Jackson Brad , Speolstra Nico , Loos Steffen , Takai Ken , Lollar Barbara Sherwood , Fredrickson Jim , Balkwill David , Onstott Tullis C. , Wimpee Charles F. , Stahl David A. 
Published: June 2003

SummaryWe characterized the diversity of sulphate‐reducing bacteria (SRB) associated with South African gold mine boreholes and deep aquifer systems in Washington State, USA. Sterile cartridges filled with crushed country rock were installed on two hydrologically isolated and chemically distinct sites at depths of 3.2 and 2.7 km below the land surface (kmbls) to allow development of biofilms. Enrichments of sulphate‐reducing chemolithotrophic (H2) and organotrophic (lactate) bacteria were established from each site under both meso‐ and thermophilic conditions. Dissimilatory sulphite reductase (Dsr) and 16S ribosomal RNA (rRNA) genes amplified from DNA extracted from the cartridges were most closely related to the Gram‐positive species Desulfotomaculum thermosapovorans and Desulfotomaculum geothermicum, or affiliated with a novel deeply branching clade. The dsr sequences recovered from the Washington State deep aquifer systems affiliated closely with the South African sequences, suggesting that Gram‐positive sulphate‐reducing bacteria are widely distributed in the deep subsurface.
Activity and population structure of nitrifying bacteria in an activated‐sludge reactor containing polymer beads
Authors: Tanaka Jun‐ichi , Syutsubo Kazuaki , Watanabe Kazuya , Izumida Hitoshi , Harayama Shigeaki 
Published: June 2003

SummaryPhoto‐crosslinked polymer beads were introduced into a laboratory activated‐sludge unit containing municipal sewage sludge and the effect on nitrifying capacity was examined. The ammonia load started at a nitrogen‐loading rate of 0.02 kg m−3 day−1 and was increased stepwise. It was found that the bead‐containing unit could almost completely oxidize ammonia (over 95%) up to a nitrogen‐loading rate of 0.216 kg m−3 day−1, whereas the maximum loading rate of the control unit (without polymer beads) was 0.096 kg m−3 day−1. The nitrifying potential of suspended and bead‐associated organisms in the bead‐containing unit was measured under different loading conditions. It was found that the bead‐associated organisms exhibited high specific activities under high loading conditions and that the contribution of the bead‐associated organisms to nitrification was greater than that of the suspended solids under these conditions. The bacterial population dynamics in the suspended solids and bead‐associated organisms were analysed by denaturing gradient gel electrophoresis (DGGE) of PCR‐amplified 16S rRNA gene fragments and by fluorescence in situ hybridization with group‐specific probes. Among the known nitrifying organisms, ammonia‐oxidizing β‐proteobacteria and Nitrospira‐related organisms were detected by these approaches. A comparison of the activity dynamics and population dynamics, however, suggested a possibility that other organisms may also have been involved in the nitrification process under high loading conditions.
Transformations of selenate and selenite by Stenotrophomonas maltophilia isolated from a seleniferous agricultural drainage pond sediment
Authors: Dungan Robert S. , Yates Scott R. , Frankenberger William T. 
Published: June 2003

SummaryA Gram‐negative bacterium, identified as Stenotrophomonas maltophilia by fatty acid analysis and 16S rRNA sequencing, was isolated from a seleniferous agricultural evaporation pond sediment collected in the Tulare Lake Drainage District, California. In cultures exposed to the atmosphere, the organism reduces selenate (SeO42−) and selenite (SeO32−) to red amorphous elemental selenium (Se°) only upon reaching stationary phase, when O2 levels are less than 0.1 mg l–1. In 48 h, S. maltophilia removed 81.2% and 99.8% of added SeO42− and SeO32− (initial concentration of 0.5 mM), respectively, from solution. Anaerobic growth experiments revealed that the organism was incapable of using SeO42−, SeO32−, SO42− or NO3– as a terminal electron acceptor. Transmission electron microscopy of cultures spiked with either Se oxyanion were found to contain spherical extracellular deposits. Analysis of the deposits by energy‐dispersive X‐ray spectroscopy revealed that they consist of Se. Furthermore, S. maltophilia was active in producing volatile alkylselenides when in the presence of SeO42− and SeO32−. The volatile products were positively identified as dimethyl selenide (DMSe), dimethyl selenenyl sulphide (DMSeS) and dimethyl diselenide (DMDSe) by gas chromatography‐mass spectrometry. Our findings suggest that this bacterium may contribute to the biogeochemical cycling of Se in seleniferous evaporation pond sediments and waters. This organism may also be potentially useful in a bioremediation scheme designed to treat seleniferous agricultural wastewater.
Use of a site‐specific recombination‐based biosensor for detecting bioavailable toluene and related compounds on roots
Authors: Casavant N. Carol , Thompson Dan , Beattie Gwyn A. , Phillips Gregory J. , Halverson Larry J. 
Published: June 2003

SummaryWe constructed and characterized a plasmid‐based genetic system that reports the expression of a toluene‐responsive promoter (PtbuA1) by effecting an irreversible, heritable change in the biosensor cell. Expression of the reporter gene gfp is strongly repressed in the absence of expression from the PtbuA1 promoter, and high level gfp expression in the original cell and its progeny is mediated by the site‐specific recombination machinery of bacteriophage P22 to initiate removal of a repressor cassette. The reporter plasmid pTolLHB was functional in two soil saprophytes, Pseudomonas fluorescens A506 and Enterobacter cloacae JL1157, with the efficiency and sensitivity to low toluene concentrations being optimal in P. fluorescens A506. In culture, 80–100% of the A506 (pTolLHB) population expressed gfp following exposure to 0.2 µm toluene for one to three hours. Compared to the response of A506 containing a plasmid‐borne PtbuA1‐gfp fusion, the recombination‐based biosensor was more sensitive at detecting low toluene and trichloroethylene concentrations. An A506 (pTolLHB) inoculum, which had a background of 2.5% of the cells expressing gfp, was introduced onto barley roots in soil microcosms. If toluene was introduced into the microcosms, after 24 h, 72% of the A506 (pTolLHB) cells recovered from roots expressed gfp, indicating bioavailable toluene to rhizosphere bacteria. When toluene was not introduced, 16.5% of the A506 (pTolLHB) cells recovered from the roots expressed gfp, indicating that natural inducers of the PtbuA1 promoter were present in the barley rhizosphere. When introduced into rhizotrons containing barley plants and toluene vapours, the biosensor allowed localization of the availability of toluene along the seminal roots. In rhizotrons that were not exposed to toluene vapours, the biosensor exhibited high PtbuA1‐promoter activity in distinct regions along the seminal roots, indicating spatial heterogeneity plant‐ or rhizosphere microbial community‐derived inducers of the PtbuA1 promoter. This recombination‐based toluene biosensor thus was useful in identifying bacterial exposure to transient or low levels of toluene, or related compounds, directly in the environment.
The marine firewormHermodice carunculatais a winter reservoir and spring‐summer vector for the coral‐bleaching pathogenVibrio shiloi
Authors: Sussman Meir , Loya Yossi , Fine Maoz , Rosenberg Eugene 
Published: June 2003

SummaryVibrio shiloi, the causative agent of bleaching of the coralOculina patagonicain the Mediterranean Sea, is present in all bleachedO. patagonicacorals in the summer (25–30°C), but can be not detected in the coral during the winter (16–20°C). Furthermore, the pathogen can not survive inO. patagonicaat temperatures below 20°C. Using fluorescencein situhybridization (FISH) with aV. shiloi‐specific oligonucleotide probe, we found that the marine firewormHermodice caranculatais a winter reservoir forV. shiloi. Worms taken directly from the sea during the winter contained ∼ 108V. shiloiper worm by FISH analysis. However, colony‐forming units (cfu) revealed only 4.1–18.3 × 104V. shiloiper worm, indicating that ∼ 99.9% of them were in the viable‐but‐not‐culturable (VBNC) state. When worms were infected withV. shiloi, most of the bacteria adhered to the worm within 24 h and then penetrated into epidermal cells. By 48 h, less than 10−4of the intactV. shiloiin the worm gave rise to colonies, suggesting that they differentiated inside the worm into the VBNC state. When worms infected withV. shiloiwere placed in aquaria containingO. patagonica, all of the corals showed small patches of bleached tissue in 7–10 days and total bleaching in 17 days. This is the first report of a reservoir and vector for a coral disease.
Rapid reversal of hepatic steatosis, and reduction of muscle triglyceride, by rosiglitazone: MRI/S studies in Zucker fatty rats
Authors: Hockings P. D. , Changani K. K. , Saeed N. , Reid D. G. , Birmingham J. , O'Brien P. , Osborne J. , Toseland C. N. , Buckingham R. E. 
Published: June 2003

Aim:  This study aimed to chart the time course and durability of the effects of rosiglitazone, a potent thiazolidinedione‐based peroxisome proliferator‐activated receptor γ agonist, on hepatic steatosis and intramyocellular lipid in an animal model of obesity, the Zucker Fatty (ZF) rat.Methods and Results:  Rosiglitazone (3 mg/kg/day p.o.) significantly reduced both liver fat content (by 59%; p < 0.05) and size (11.5%; p < 0.05) in male ZF rats that received between 3 days and 1 week of treatment, and these reductions were maintained for at least 12 weeks. Liver fat content measured by magnetic resonance spectroscopy (MRS) correlated closely and positively with plasma insulin levels (reduced by 89% within a week, r = 0.8) and with postmortem histological fat fractional volume (r = 0.89). Similarly, liver volume measured by magnetic resonance imaging (MRI) correlated closely with postmortem wet weight (r = 0.99). MRS also showed, and numbers of lipid vacuoles counted in transmission electron micrographs confirmed, that rosiglitazone significantly reduced the elevated intramyocellular lipid seen in ZF rat skeletal muscle by at least 40% (p < 0.05).Conclusions:  Localized MRS and MRI showed that rosiglitazone reversed the hepatic steatosis, hepatomegaly and intramyocellular lipid, characteristic of the ZF rat, an animal model of obesity.
Identification of a nerve ending‐enriched 29‐kDa protein, labeled with [3‐32P]1,3‐bisphosphoglycerate, as monophosphoglycerate mutase: inhibition by fructose‐2,6‐bisphosphate via enhancement of dephosphorylation
Authors: Ikemoto Atsushi , Ueda Tetsufumi 
Published: June 2003

AbstractGlucose metabolism is of vital importance in normal brain function. Evidence indicates that glycolysis, in addition to production of ATP, plays an important role in maintaining normal synaptic function. In an effort to understand the potential involvement of a glycolytic intermediate(s) in synaptic function, we have prepared [3‐32P]1,3‐bisphosphoglycerate and [32P]3‐phosphoglycerate and sought their interaction with a specific nerve‐ending protein. We have found that a 29‐kDa protein is the major component labeled with either [3‐32P]1,3‐bisphosphoglycerate or [32P]3‐phosphoglycerate. The protein was identified as monophosphoglycerate mutase (PGAM). This labeling was remarkably high in the brain and synaptosomal cytosol fraction, consistent with the importance of glycolysis in synaptic function. Of interest, fructose‐2,6‐bisphosphate (Fru‐2,6‐P2) inhibited PGAM phosphorylation and enzyme activity. Moreover, Fru‐2,6‐P2 potently stimulated release of [32P]phosphate from the 32P‐labeled PGAM (EC50 = 1 µm), suggesting that apparent reduction of PGAM phosphorylation and enzyme activity by Fru‐2,6‐P2 may be due to stimulation of dephosphorylation of PGAM. The significance of these findings is discussed.
Microglial apolipoprotein E and astroglial apolipoprotein J expression in vitro: opposite effects of lipopolysaccharide
Authors: Saura Josep , Petegnief Valerie , Wu Xin , Liang Yanbin , Paul Steven M. 
Published: June 2003

AbstractApolipoprotein E (apoE) and apoJ are lipid carriers produced in the brain primarily by glial cells. A variety of glial‐activating stimuli induce a parallel upregulation of both apolipoproteins expression in vivo and in vitro. To further characterize the cell type and mechanisms by which apoE and apoJ expression are upregulated in activated glia, mixed glial cultures from neonatal rat cortex were treated with the endotoxin lipopolysaccharide (LPS). LPS induced dose‐dependent increases in apoJ and decreases in apoE expression and secretion with maximum effects at 1–10 ng/mL and 0.1–1 µg/mL, respectively. Experiments with enriched astroglial and microglial cultures demonstrated that apoE and apoJ expression are predominantly microglial and astroglial, respectively. Given the pivotal role that nuclear factor‐κB (NF‐κB) plays in glial activation, we assessed its possible role in mediating apoE and apoJ expression by activated glia. LPS robustly increased NF‐κB activation in mixed glial cultures. Two NF‐κB inhibitors, aspirin (10 mm) and MG‐132 (0.1 µm), blocked basal apoE and apoJ secretion as well as LPS‐induced apoJ secretion. These data demonstrate that glial apoE and apoJ expression are independently regulated by LPS in microglia and astroglia, respectively, and that activated microglia are the predominant source of apoE in mixed glial cultures. The transcription factor NF‐κB appears to be a critical mediator of LPS‐stimulated apoJ expression from astroglia.
c‐Fos is essential for the response of the tyrosine hydroxylase gene to depolarization or phorbol ester
Authors: Sun Baoyong , Tank A. William 
Published: June 2003

AbstractTyrosine hydroxylase (TH) gene transcription rate increases in response to numerous pharmacological and physiological stimuli. The AP1 site within the TH gene proximal promoter is thought to play an important role in mediating many of these responses; however, it is unclear which AP1 factors are required. To investigate whether c‐Fos is essential for the response of the TH gene to different stimuli, c‐Fos‐deficient PC12 cell lines were produced utilizing an antisense RNA strategy. In these cell lines, stimulus‐induced increases in c‐Fos protein levels were dramatically attenuated, while c‐Jun and CREB levels remained unchanged. TH gene transcription rate increased from four‐ to eight‐fold in control cells after treatment with either 50 mm KCl or TPA. These responses were dramatically decreased in the c‐Fos‐deficient cell lines. In contrast, c‐Fos down‐regulation had little effect on the response of the TH gene to forskolin. Stimulation of TH gene promoter activity, which was observed in control cell lines treated with either 50 mm KCl or TPA was also dramatically inhibited in the c‐Fos‐deficient cells. These results suggest that c‐Fos induction is essential for maximal stimulation of the TH gene in response to either depolarization or PKC activation in PC12 cells.
α‐Synuclein up‐regulates expression of caveolin‐1 and down‐regulates extracellular signal‐regulated kinase activity in B103 neuroblastoma cells: role in the pathogenesis of Parkinson's disease
Authors: Hashimoto Makoto , Takenouchi Takato , Rockenstein Edward , Masliah Eliezer 
Published: June 2003

Abstractα‐Synuclein accumulation plays an important role in the pathogenesis of Lewy body disease (LBD) and Parkinson's disease (PD). Although the mechanisms are not yet clear, it is possible that dysregulation of the extracellular signal‐regulated kinase (ERK) might play a role. As caveolins form scaffolds onto which signaling molecules such as ERK can assemble, we propose that signaling alterations associated with α‐synuclein accumulation and neurodegeneration, might be mediated via caveolae. Therefore, the objective of the present study was to investigate the potential contribution of alterations in the caveolar system in mediating α‐synuclein effects on the ERK signaling pathway. For this, synuclein‐transfected B103 neuroblastoma cells were used as a model system. In this cell line, caveolin‐1 expression was up‐regulated, whereas, ERK was down‐regulated. ERK was weakly but consistently co‐immunoprecipitated with α‐synuclein but caveolin‐1 did not co‐immunoprecipitate with α‐synuclein. Moreover, treatment of α‐synuclein‐ overexpressing cells with caveolin‐1 antisense oligonucleotides resulted in stimulation of ERK activity, with amelioration of the neuritic alterations. Transduction of α‐synuclein‐overexpressing cells, with an adenoviral vector directing the expression of ERK, resulted in suppression of caveolin‐1 expression and re‐establishment of the normal patterns of neurite outgrowth. These results suggest that α‐synuclein may also interfere with ERK signaling by dysregulating caveolin‐1 expression. Thus, the caveolin‐1/ERK pathway could be a therapeutic target for the α‐synuclein‐related neurodegenerative disorders.
Role of protein phosphatase 2C from bovine adrenal chromaffin cells in the dephosphorylation of phospho‐serine 40 tyrosine hydroxylase
Authors: Bevilaqua Lia R. M. , Cammarota Martín , Dickson Phillip W. , Sim Alistair T. R. , Dunkley Peter R. 
Published: June 2003

AbstractTyrosine hydroxylase (TH) is the rate‐limiting enzyme in the synthesis of catecholamines. It is dephosphorylated by protein phosphatase (PP) 2A and PP2C. In this study we used a fixed amount of bacterially expressed rat TH (5 µm), phosphorylated only at serine 40 (pSer40TH), to determine the PP activities against this site that are present in extracts from the bovine adrenal cortex, adrenal medulla, adrenal chromaffin cells and rat striatum. We found that PP2C was the main TH phosphatase activity in extracts from the adrenal medulla and adrenal chromaffin cells. In adrenal cortex extracts PP2C and PP2A activities toward pSer40TH did not differ significantly. PP2A was the main TH phosphatase activity in extracts from rat striatum. Kinetic studies with extracts from adrenal chromaffin cells showed that when higher concentrations of pSer40TH (> 5 µm) were used the activity of PP2C increased more than the activity of PP2A. PP2C was maximally activated by 1.25 mm Mn2+ and by 5 mm Mg2+ but was inhibited by calcium. Our data suggest a more important role for PP2C than was previously suggested in the dephosphorylation of serine 40 on TH.
Cyclosporin A prevents calpain activation despite increased intracellular calcium concentrations, as well as translocation of apoptosis‐inducing factor, cytochrome c and caspase‐3 activation in neurons exposed to transient hypoglycemia
Authors: Ferrand‐Drake Michel , Zhu Changlian , Gidö Gunilla , Hansen Anker J. , Karlsson Jan‐Olof , A. Bahr Ben , Zamzami Naoufal , Kroemer Guido , Chan Pak H. , Wieloch Tadeusz , Blomgren Klas 
Published: June 2003

AbstractBlockade of mitochondrial permeability transition protects against hypoglycemic brain damage. To study the mechanisms downstream from mitochondria that may cause neuronal death, we investigated the effects of cyclosporin A on subcellular localization of apoptosis‐inducing factor and cytochrome c, activation of the cysteine proteases calpain and caspase‐3, as well as its effect on brain extracellular calcium concentrations. Redistribution of cytochrome c occurred at 30 min of iso‐electricity, whereas translocation of apoptosis‐inducing factor to nuclei occurred at 30 min of recovery following 30 min of iso‐electricity. Active caspase‐3 and calpain‐induced fodrin breakdown products were barely detectable in the dentate gyrus and CA1 region of the hippocampus of rat brain exposed to 30 or 60 min of insulin‐induced hypoglycemia. However, 30 min or 3 h after recovery of blood glucose levels, fodrin breakdown products and active caspase‐3 markedly increased, concomitant with a twofold increase in caspase‐3‐like enzymatic activity. When rats were treated with neuroprotective doses of cyclosporin A, but not with FK 506, the redistribution of apoptosis‐inducing factor and cytochrome c was reduced and fodrin breakdown products and active caspase‐3 immuno‐reactivity was diminished whereas the extracellular calcium concentration was unaffected. We conclude that hypoglycemia leads to mitochondrial permeability transition which, upon recovery of energy metabolism, mediates the activation of caspase‐3 and calpains, promoting cell death.
Bcl‐2‐related protein family gene expression during oligodendroglial differentiation
Authors: Itoh Takayuki , Itoh Aki , Pleasure David 
Published: June 2003

AbstractOligodendroglial lineage cells (OLC) vary in susceptibility to both necrosis and apoptosis depending on their developmental stages, which might be regulated by differential expression of Bcl‐2‐related genes. As an initial step to test this hypothesis, we examined the expression of 19 Bcl‐2‐related genes in purified cultures of rat oligodendroglial progenitors, immature and mature oligodendrocytes. All ‘multidomain’ anti‐apoptotic members (Bcl‐x, Bcl‐2, Mcl‐1, Bcl‐w and Bcl2l10/Diva/Boo) except Bcl2a1/A1 are expressed in OLC. Semiquantitative and real‐time RT‐PCR revealed that Bcl‐xL and Mcl‐1 mRNAs are the dominant anti‐apoptotic members and increase four‐ and twofold, respectively, with maturation. Bcl‐2 mRNA is less abundant than Bcl‐xL mRNA in progenitors and falls an additional 10‐fold during differentiation. Bcl‐w mRNA also increases, with significant changes in its splicing pattern, as OLC mature. Transfection studies demonstrated that Bcl‐xL overexpression protects against kainate‐induced excitotoxicity, whereas Bcl‐2 overexpression does not. As for ‘multidomain’ pro‐apoptotic members (Bax, Bad and Bok/Mtd), Bax and Bak are highly expressed throughout differentiation. Among ‘BH3 domain‐only’ members examined (Bim, Biklk, DP5/Hrk, Bad, Bid, Noxa, Puma/Bbc3, Bmf, BNip3 and BNip3L), BNip3 and Bmf mRNAs increase markedly during differentiation. These results provide basic information to guide further studies on the roles for Bcl‐2‐related family proteins in OLC death.
Presenilin endoproteolysis mediated by an aspartyl protease activity pharmacologically distinct from γ‐secretase
Authors: Campbell William A. , Reed Megan L. O. , Strahle Jennifer , Wolfe Michael S. , Xia Weiming 
Published: June 2003

AbstractPresenilin (PS)‐dependent γ‐secretase cleavage is the final proteolytic step in generating amyloid β protein (Aβ), a key peptide involved in the pathogenesis of Alzheimer's disease. PS undergoes endoproteolysis by an unidentified ‘presenilinase’ to generate the functional N‐terminal and C‐terminal fragment heterodimers (NTF/CTF) that may harbor the γ‐secretase active site. To better understand the relationship between presenilinase and γ‐secretase, we characterized the biochemical properties of presenilinase and compared them with those of γ‐secretase. Similar to γ‐secretase, presenilinase was most active at acidic pH 6.3. Aspartyl protease inhibitor pepstatin A blocked presenilinase activity with an IC50 of ∼ 1 µm. Difluoroketone aspartyl protease transition state analogue MW167 was relatively selective for presenilinase (IC50 < 1 µm) over γ‐secretase (IC50−16 µm). Importantly, removing the transition state mimicking moiety simultaneously abolished both presenilinase and γ‐secretase inhibition, suggesting that presenilinase, like γ‐secretase, is an aspartyl protease. Interestingly, several of the most potent γ‐secretase inhibitors (IC50 = 0.3 or 20 nm) failed to block presenilinase activity. Although de novo generation of PS1 fragments coincided with production of Aβin vitro, blocking presenilinase activity without reducing pre‐existing fragment levels permitted normal de novo generation of Aβ and amyloid intracellular domain. Therefore, presenilinase has characteristics of an aspartyl protease, but this activity is distinct from γ‐secretase.