bluuebunny/crossref_metadata_2025_split huggingface dataset:
Superoxide Reductases
Authors: Pereira Alice S. , Tavares Pedro , Folgosa Filipe , Almeida Rui M. , Moura Isabel , Moura José J. G. 
Published: May 2007

AbstractReactive oxygen species (ROS), when in excess, are among the most deleterious species an organism can deal with. The physiological effects of ROS include amino acid chain cleavage, DNA degradation and lipid oxidation, among others. They can be formed in the cytoplasm in a variety of ways, including autooxidation reactions (FMN‐ and FAD‐containing enzymes) and Fenton reactions as a result of the cytoplasmatic pool of iron ions. The superoxide anion (O2·–), despite its short half‐life in solution, is particularly pernicious as it can form other reactive ROS (such as the strong oxidant peroxynitrite) or oxidize and/or reduce cellular components. For strict anaerobic or microaerophilic bacteria it is of particular importance to be able to dispose of ROS in a controlled manner, especially if these organisms are temporarily exposed to air. This review aims to describe the structural characteristics of superoxide reductases (SORs) and mechanistic aspects of biological superoxide anion reduction. SORs can be considered the main class of enzymes behind the oxygen detoxification pathway of anaerobic and microaerophilic bacteria. The geometry of the active site (three classes have been described), the possible electron donors in vivo and the current hypothesis for the catalytic mechanism will be discussed. Some phylogenetic considerations are presented, regarding the primary structure of SORs currently available in genome databases.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
CE assay of methylmalonyl‐coenzyme‐A mutase activity
Authors: Carlucci Filippo , Rosi Francesca , Tommassini Valentina , Tabucchi Antonella 
Published: May 2007

AbstractMethylmalonyl‐coenzyme A mutase (MCM) is a 5′‐deoxyadenosylcobalamin‐linked mitochondrial enzyme that catalyzes the isomerization of L‐methylmalonyl‐coenzyme A to succinyl‐coenzyme A. We described a method for methylmalonyl‐CoA and succinyl‐CoA separation by CE, suitable for the evaluation of MCM activity. The working conditions for optimal separation were obtained in order to achieve the best resolution in the shortest analysis time. The optimization of buffer composition together with other variables, such as injection time, separation voltage, migration time, and capillary temperature, resulted in a solution of 30 mM NaH2PO4 containing 15 mM SDS, pH 3.2. Separations were carried out in an uncoated fused‐silica capillary (55 cm, 50 μm id) at −25 kV, reading at 254 nm. The method performance was evaluated by measuring total and holo‐MCM activity in biological matrices such as rat liver and human peripheral blood lymphocytes (PBL). The mean MCM activity was expressed in nmol/h/mg protein of tissue/cell extract and was calculated from the amount of reaction product formed. The rapidity of analysis and utmost precision (repeatability and within‐laboratory reproducibility) point out the potentialities of the proposed method for the differential diagnosis of methylmalonic acidemia, in relation to protein or coenzyme defects.
Molecular characterization of the role of orphan receptor small heterodimer partner in development of fatty liver
Authors: Huang Jiansheng , Iqbal Jahangir , Saha Pradip K. , Liu Jun , Chan Lawrence , Hussain Mahmood M. , Moore David D. , Wang Li 
Published: May 2007

Abstract

The orphan receptor Small Heterodimer Partner (

SHP,

NROB2) regulates metabolic pathways, including hepatic bile acid, lipid, and glucose homeostasis. We reported that

SHP
-deletion in leptin-deficient

OB

−/− mice increases insulin sensitivity, and prevents the development of fatty liver. The prevention of steatosis in

OB

−/−/

SHP

−/− double mutants is not due to decreased body weight but is associated with increased hepatic very-low-density lipoprotein (VLDL) secretion and elevated microsomal triglyceride transfer protein (MTP) mRNA and protein levels. SHP represses the transactivation of the MTP promoter and the induction of MTP mRNA by LRH-1 in hepatocytes. Adenoviral overexpression of SHP inhibits MTP activity as well as VLDL-apoB protein secretion, and RNAi knockdown of SHP exhibits opposite effects. The expression of SHP in induced in fatty livers of

OB

−/− mice and other genetic or dietary models of steatosis, and acute overexpression of SHP by adenovirus, result in rapid accumulation of neutral lipids in hepatocytes. In addition, the pathways for hepatic lipid uptake and lipogenic program are also downregulated in

OB

−/−/

SHP

−/− mice, which may contribute to the decreased hepatic lipid content.

Conclusion:

These studies demonstrate that SHP regulates the development of fatty liver by modulating hepatic lipid export, uptake, and synthesis, and that the improved peripheral insulin sensitivity in

OB

−/−/

SHP

−/− mice is associated with decreased hepatic steatosis. (HEPATOLOGY 2007.)
Myxovirus-1 and protein kinase haplotypes and fibrosis in chronic hepatitis C virus
Authors: Yee Leland J. , Tang Yong-Ming , Kleiner David E. , Wang Dai , Im KyungAh , Wahed Abdus , Tong Xiaomei , Rhodes Shannon , Su Xiaowen , Whelan Margaret R. , Fontana Robert J. , Ghany Marc G. , Borg Brian , Liang Jake T. , Yang Huiying 
Published: May 2007

Abstract

Candidate genes, including

myxovirus resistance-1 (Mx1), protein kinase (PKR), transforming growth factor
-β

1 (TGF-β), interleukin-10 (IL-10), and interferon-gamma (IFN-γ),

were evaluated for associations with liver fibrosis in 374 treatment-naive patients with genotype-1 chronic HCV infection [194 Caucasian Americans (CAs) and 180 African Americans (AAs)], using a genetic haplotype approach. Among the 18 haplotypes that occurred with a frequency ≥5% in the cohort overall, the

Mx1-(-123C)-(+6886A)-(+19820G(379V))-(+38645T)

(abbreviated

Mx1-CAGT),

and

PKR-(+110T)-(+7949G)-(+13846A)-(+22937T)-(+40342T)

(abbreviated

PKR-TGATT)

haplotypes were independently associated with less severe hepatic fibrosis (Ishak ≥ 3 versus <3). These associations persisted after adjustment for potential confounders such as alcohol use, sex, age (which is strongly correlated with the estimated duration of HCV infection [Spearman's correlation coefficient (

r

s) = 0.6)], and race (for

Mx1-CAGT

: OR = 0.33; 95% CI: 0.16-0.68;

P

= 0.0027; and for

PKR-TGATT

: OR = 0.56; 95% CI: 0.32-0.98;

P

= 0.0405). Population structure was evaluated using the structured association method using data from 161 ancestry-informative markers and did not affect our findings. We used an independent cohort of 34 AA and 160 CA in an attempt to validate our findings, although notable differences were found in the characteristics of the two patient groups. Although we observed a similar protective trend for the

Mx1-CAGT

haplotype in the validation set, the association was not statistically significant.

Conclusion:

In addition to other factors, polymorphisms in cytokine genes may play a role in the progression of HCV-related fibrosis; however, further studies are needed. (HEPATOLOGY 2007.)
MRI detection of macrophages labeled using micrometer‐sized iron oxide particles
Authors: Williams John B. , Ye Qing , Hitchens T. Kevin , Kaufman Christina L. , Ho Chien 
Published: May 2007

AbstractPurposeTo evaluate cellular labeling of immune cells using micron‐sized iron oxide particles (MPIOs) and evaluate the MR relaxivity and MRI detection of the labeled cells.Materials and MethodsImmune cells isolated from mice and rats were labeled with three different sizes of MPIO particles (0.35, 0.90, or 1.63 μm). These labeled cells were characterized using transmission electron microscopy (TEM), fluorescence microscopy, flow cytometry, MR relaxometry, and MRI.ResultsMacrophage uptake of MPIOs was found to be highest for the 1.63‐μm size particles. MR relaxivity measurements indicated greater spin‐spin relaxation for MPIO‐labeled cells relative to cells labeled with nanometer‐sized ultra‐small superparamagnetic iron oxide (USPIO) particles with similar iron content. TEM and fluorescence microscopy indicated cellular uptake of multiple MPIO particles per cell. Macrophages labeled with 1.63‐μm MPIOs had an average cellular iron uptake of 39.1 pg/cell, corresponding to approximately 35 particles per cell.ConclusionCells labeled with one or more MPIO particles could be readily detected ex vivo at 11.7 Tesla and after infusion of the MPIO‐labeled macrophages into the kidney of a rat, hypointense regions of the outer cortex are observed, in vivo, by MRI at 4.7 Tesla. J. Magn. Reson. Imaging 2007;25:1210–1218. © 2007 Wiley‐Liss, Inc.
Quantitative evaluation of the relaxivity effects of iodine on GD‐DTPA enhanced MR arthrography
Authors: Ganguly Arundhuti , Gold Garry E. , Butts Pauly Kim , Mayer Dirk , Moseley Michael M. , Pelc Norbert J. , Fahrig Rebecca 
Published: May 2007

AbstractPurposeTo quantify the effect of iodine on the gadolinium (Gd) contrast‐enhanced signal in MR arthrography.Materials and MethodsSaline solutions of Gd contrast agent (0–1 mmol/liter) were mixed with iodinated contrast agent (0–185 mmol/liter). The T1 and T2 relaxation constants of these solutions were measured at 1.5T. Different types of commonly used iodinated contrast agents as well as sodium iodide (NaI) solutions were also analyzed.ResultsIodine caused significant T2 shortening and some T1 shortening in Gd contrast solutions. Both contrast agents independently obeyed the standard relaxation relation, and their mixture obeyed a modified version of this relation. The side chains in various iodine molecules and their viscosities affected the relaxation properties differently. For various spin‐echo (SE) sequences, the signal from synovial fluid containing different concentrations of the two contrast agents was calculated. The T2‐weighted signal appeared to be most affected by the increase in iodine concentrations. In the absence of Gd contrast, all SE sequences showed an initial increase in signal from iodine contrast.ConclusionA generalized relation for the relaxivities of Gd contrast in the presence of iodine was established. The side chains of iodine contrast were found to alter the relaxivities of Gd contrast. Imaging with proton density (PD)‐weighted SE with only iodine contrast agent was found to be feasible. J. Magn. Reson. Imaging 2007;25:1219–1225. © 2007 Wiley‐Liss, Inc.
Contrast‐to‐noise ratio (CNR) as a quality parameter in fMRI
Authors: Geissler Alexander , Gartus Andreas , Foki Thomas , Tahamtan Amir Reza , Beisteiner Roland , Barth Markus 
Published: May 2007

AbstractPurposeTo evaluate the impact of data quality on the localization of brain activation in functional magnetic resonance imaging (fMRI) and to explore whether the temporal contrast‐to‐noise‐ratio (CNR) provides a quantitative parameter to estimate fMRI quality.Materials and MethodsWe investigated two methods for defining the CNR by comparing them on a single‐run, single session, as well as on a group‐wise basis. The CNRs of healthy subjects and a group of patients with brain lesions were calculated using two different strategies: one based on a general linear model (GLM) analysis (CNR_SPM), and one that acts as an adaptive low‐pass filter and assumes that the high‐frequency components contain the temporal noise (CNR_SG). Runs with low CNR were identified as outliers using a common exclusion criterion (2 × standard deviation (SD)).ResultsThe results of the two CNR methods are highly correlated. Both between and within subjects and patients the CNR showed quite large variations, but the average CNR did not differ between a group of healthy subjects and a patient group. In total, seven of 213 runs (3.3% of all runs) had to be excluded when CNR_SG was used, and 14 of 213 (6.6%) runs had to be excluded when CNR_SPM was used.ConclusionCalculating the CNR using an adaptive low‐pass filter gives similar results to a GLM‐based approach and could be advantageous for cases in which the hemodynamic response function (HRF) differs significantly from common assumptions. The CNR can be used to identify and exclude runs with suboptimal CNR, and to identify sessions with insufficient data quality. The CNR may serve as a quantitative and intuitive parameter to assess the performance and quality of clinical fMRI investigations, including information on both functional performance (contrast) and data quality (noise caused by the system and physiology). J. Magn. Reson. Imaging 2007;25:1263–1270. © 2007 Wiley‐Liss, Inc.
Activation of epidermal growth factor receptors in astrocytes: From development to neural injury
Authors: Liu Bin , Neufeld Arthur H. 
Published: May 2007

AbstractThe epidermal growth factor receptor (EGFR) pathway controls the phenotypic characteristics of astrocytes. In the developing central nervous system (CNS), activation of the EGFR pathway induces astrocyte differentiation, forming the cribriform structure that surrounds axons and providing a supportive environment for neurons. In the adult CNS, the EGFR pathway is absent from astrocytes but is highly up‐regulated and activated following neuronal injury. Activation of the EGFR pathway triggers quiescent astrocytes to become reactive astrocytes. Although astrocytes regulated by the EGFR pathway play constructive roles in the developing CNS, astrocytes that become reactive in response to activation of the EGFR pathway appear to be destructive to neurons in the adult CNS. The reappearance and activation of EGFRs in astrocytes under pathological conditions may activate a developmental process in an adult tissue. Regulation of EGFR function in astrocytes may be a new therapeutic strategy for the treatment of neural disorders. © 2007 Wiley‐Liss, Inc.
Astroglia overexpressing heme oxygenase‐1 predispose co‐cultured PC12 cells to oxidative injury
Authors: Song Linyang , Song Wei , Schipper Hyman M. 
Published: May 2007

AbstractThe mechanisms responsible for the progressive degeneration of dopaminergic neurons and pathologic iron deposition in the substantia nigra pars compacta of patients with Parkinson's disease (PD) remain unclear. Heme oxygenase‐1 (HO‐1), the rate‐limiting enzyme in the oxidative degradation of heme to ferrous iron, carbon monoxide, and biliverdin, is upregulated in affected PD astroglia and may contribute to abnormal mitochondrial iron sequestration in these cells. To determine whether glial HO‐1 hyper‐expression is toxic to neuronal compartments, we co‐cultured dopaminergic PC12 cells atop monolayers of human (h) HO‐1 transfected, sham‐transfected, or non‐transfected primary rat astroglia. We observed that PC12 cells grown atop hHO‐1 transfected astrocytes, but not the astroglia themselves, were significantly more susceptible to dopamine (1 μM) + H2O2(1 μM)‐induced death (assessed by nuclear ethidium monoazide bromide staining and anti‐tyrosine hydroxylase immunofluorescence microscopy) relative to control preparations. In the experimental group, PC12 cell death was attenuated significantly by the administration of the HO inhibitor, SnMP (1.5 μM), the antioxidant, ascorbate (200 μM), or the iron chelators, deferoxamine (400 μM), and phenanthroline (100 μM). Exposure to conditioned media derived from HO‐1 transfected astrocytes also augmented PC12 cell killing in response to dopamine (1 μM) + H2O2(1 μM) relative to control media. In PD brain, overexpression of HO‐1 in nigral astroglia and accompanying iron liberation may facilitate the bioactivation of dopamine to neurotoxic free radical intermediates and predispose nearby neuronal constituents to oxidative damage. © 2007 Wiley‐Liss, Inc.
Differential effects of polyglutamine proteins on nuclear organization and artificial reporter splicing
Authors: Sun June , Xu Hongzhi , Negi Sandeep , Subramony S.H. , Hebert Michael D. 
Published: May 2007

AbstractNuclear inclusions formed by proteins with expanded polyglutamine tracts are found in several neurodegenerative diseases. The effect of nuclear inclusions formed by these disease proteins on the functional organization of the nucleus is only partially understood. In particular, it is not known whether polyglutamine disease proteins disrupt the function of Cajal bodies, which are subnuclear domains that play a role in the biogenesis of small nuclear ribonucleoproteins (snRNPs). snRNPs are an integral part of the pre‐mRNA splicing machinery, so it is possible that mutant proteins that alter Cajal body activity indirectly affect pre‐mRNA splicing. Here, we evaluate three different polyglutamine disease proteins—ataxin‐1, ataxin‐3, and huntingtin—for their ability to disrupt Cajal body localization and reduce the splicing of an artificial reporter in HeLa cells. Consistent with previous observations, ataxin‐1 inclusions do not drastically alter the localization of Cajal bodies. In contrast, ataxin‐3 inclusions associate with this structure. Inclusions formed by a fragment of the huntingtin protein do not associate with Cajal bodies or PML bodies, another subnuclear domain. Among the three disease proteins, only ataxin‐3 significantly decreases the splicing of an artificial reporter. These results support the hypothesis that different mutant proteins vary in their ability to disrupt nuclear organization and function. © 2007 Wiley‐Liss, Inc.
Discaria trinervis – Frankia symbiosis promotion by saprophytic actinomycetes
Authors: Solans Mariana 
Published: May 2007

AbstractThe influence of saprophytic actinomycetes strains on the Discaria trinervis – Frankia actinorhizal symbiosis was investigated. Three strains out of 122 isolated from the rhizosphere and rhizoplane of D. trinervis with multiple enzymatic activities, were selected for plant growth experiments: Streptomyces (BCRU‐MM40), Actinoplanes (BCRU‐ME3) and Micromonospora (BCRU‐MM18). Inoculated seedlings of Discaria trinervis were grown in glass tubes with vermiculite‐sand for 12 weeks. They were inoculated either with a single saprophytic strain or a combination of one or two of them together with the symbiotic N2 fixing strain Frankia BCU110501. The saprophytic strains were applied in two experimental series, i.e. mycelium + supernatant simultaneously or mycelium and supernatant (growth medium free of cells) separately. Micromonospora strain MM18 showed a direct promotion effect on shoot growth, when plants were inoculated with mycelium and supernatant together. Streptomyces strain MM40 and Actinoplanes strain ME3 promoted the actinorhizal symbiosis with Frankia and consequently the development of plant shoots, when supernatant was involved as inoculum. It is supposed, that the strains MM18, MM40 and ME3 produce bioactive metabolites, which are released into the culture medium. The saprophytic strains studied could be considered as “promoting or helper rhizoactinomycetes” of the actinorhizal plant D. trinervis. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of inoculation with Penicillium albidum, a phosphate‐solubilizing fungus, on the growth of Trifolium pratense cropped in a volcanic soil
Authors: Morales Alfredo , Alvear Marysol , Valenzuela Eduardo , Rubio Rosa , Borie Fernando 
Published: May 2007

AbstractVolcanic soils in the south of Chile have an elevated quantity of total P, which is scarcely available due to its high P fixation capacity. One strategy for increasing the availability of P for the vegetables that grow there would be to use phosphate‐solubilizing microorganisms. In one assay conducted in a greenhouse on a volcanic soil, the effect of inoculation with Penicillium albidum, a phosphate‐solubilizing fungus, was studied on the growth of red clover (Trifolium pratense L). Some chemical and biological properties of the soil were also evaluated. There were three treatments: a) active inoculum [In(+)], b) inactive inoculum (autoclaved) [In(–)] and c) without inoculum [In(0)], each one done in three replicates. The In(+) significantly (P < 0.050) increased the growth of the plants, contributing particularly to root development. The P mobilized to the shoot with In(+) was higher than twofold related to In(0) and In(–) treatments; however, the In(+) plants had similar concentration of shoot P. In the soil, available‐P was not statistically different (P < 0.050) among the treatments but phosphatase activity in In(+) was higher (P < 0.050) in comparison to In(0). The results suggest that Penicillium albidum contributed to growth and nutrition of the red clover through the induction of root development and enhancing phosphate mobilization from the soil and into the plant. It is concluded that Penicillium albidum, under greenhouse conditions, in soils deficient in available P can increase the inoculation potential for volcanic soils in Chile. Anyway further studies are required, especially in organic farming where the use of soluble P fertilizer is avoided. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Isolation of a FAD‐GPDH gene encoding a mitochondrial FAD‐dependent glycerol‐3‐phosphate dehydrogenase from Dunaliella salina
Authors: Yang Wanggui , Cao Yi , Sun Xiaofei , Huang Fei , He Qinghua , Qiao Dairong , Bai Linhan 
Published: May 2007

AbstractThe mitochondrial FAD‐dependent glycerol‐3‐phosphate dehydrogenase (FAD‐GPDH), recently reported in plants, has been detailed in yeast and animal systems. It oxidizes glycerol‐3‐phosphate (G‐3‐P) to dihydroxyacetone phosphate (DHAP) on the outer surface of mitochondrial inner membrane. A cDNA encoding the Dunaliella salina mitochondrial glycerol‐3‐phosphate dehydrogenase (DsFAD‐GPDH) has been cloned and sequenced. The full length cDNA is 2791 bp, with an open reading frame (ORF) encoding 650 predicted amino acids, which show strong homology to reported FAD‐GPDHs and have an apparent mitochondrial targeting sequence in the N‐terminal. The sequence has been submitted to the GenBank database under Accession No. DQ916107. Results of Real‐Time Quantitative PCR and enzymatic assays show that expression of DsFAD‐GPDH is enhanced at first by salt treatment, and repressed by oxygen deficiency and cold stress. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient transformation of Lactococcus lactis IL1403 and generation of knock‐out mutants by homologous recombination
Authors: Gerber Simon D. , Solioz Marc 
Published: May 2007

AbstractLactococcus lactis IL1403 is a Gram‐positive bacterium of great biotechnological interest for food grade applications. Its use is however hampered by the difficulty to efficiently transform this strain. We here describe a detailed, optimized electrotransformation protocol which yields a transformation efficiency of 106 cfu/μg of DNA with the two E. coli Gram‐positive shuttle vectors pC3 and pVA838. The utility of the protocol was demonstrated by the generation of single‐ and double‐knock‐out mutants by homologous recombination. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High temperature experiments: a way to observe Raman scattering in luminescent samples
Authors: Raffaëlly L. , Champagnon B. 
Published: May 2007

AbstractTwo methods to decrease the luminescence of a sample and to observe the Raman scattering are described: the change of the wavelength of excitation or the change of the temperature of the sample. The evolution of the luminescence intensity with temperature is explained by the use of an energy model with a metastable state and radiationless processes whose activation energy can be calculated. This method is applied with success to a Roman silicate glass: the Raman scattering initially hidden by the luminescence is then observed. Copyright © 2007 John Wiley & Sons, Ltd.