bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of the voltage‐ and Ca2+‐dependent BK potassium channel subunits BKβ1 and BKβ4 in rodent astrocytes
Authors: Seidel Katharina N. , Derst Christian , Salzmann Mikhail , HöLtje Markus , Priller Josef , Markgraf René , Heinemann Stefan H. , Heilmann Heike , Skatchkov Serguei N. , Eaton Misty J. , Veh RüDiger W. , Prüss Harald
Published: March 2011

Large‐conductance Ca2+‐activated (BK) potassium channels are centrally involved in neurovascular coupling, immunity, and neural transmission. The ability to be synergistically activated by membrane depolarization, different ligands and intracellular Ca2+ links intracellular signaling and membrane excitability. The diverse physiological functions of BK channels crucially depend on regulatory β subunits. Although first studies characterized the neuronal distribution of BKβ subunits in the rodent brain, it is largely unknown which β subunit proteins are expressed in astrocytes and thus mediate these regulatory effects. We therefore analyzed the expression of BKβ subunits in rat and mouse brain and glial cell cultures. A monospecific polyclonal antibody against the BKβ4 channel subunit was raised, affinity‐purified and extensively characterized. BKβ4 and to a lesser degree BKβ1 transcripts and protein were detected in several astrocytic populations and cultured cells. Particularly strong BKβ4 immunostaining was detected in astrocytic progenitors derived from the subventricular zone. The overlapping expression of BKα and BKβ4 in astrocytes implies a functional relationship and suggests that BKβ4 is an important accessory β subunit for astrocytic BK channels. In addition, BKβ4 might exert effects independent of the α subunit as functional heterologous co‐expression of Nav1.6 and BKβ4 resulted in reduced Nav1.6 sodium currents. Thus, BKβ4 expression in astrocytes likely participates in regulating astrocytic voltage gradients and maintaining K+ homeostasis, hence enabling astrocytes to fulfill their complex regulatory influence on proper brain function. © 2011 Wiley‐Liss, Inc.
Hepcidin directly inhibits transferrin receptor 1 expression in astrocytes via a cyclic AMP‐protein kinase a pathway
Authors: Du Fang , Qian Christopher , Ming Qian Zhong , Wu Xiao‐Mei , Xie Hui , Yung Wing‐Ho , Ke Ya
Published: March 2011

Hepcidin, an iron‐regulatory hormone, plays a central role in iron homeostasis in peripheral tissues. The widespread distribution of hepcidin in the brain implies that the hormone may be essential for brain iron homeostasis. Here, we investigated the effects of hepcidin on the expression of iron uptake proteins, including transferrin receptor 1 (TfR1) and divalent metal transporter1 (DMT1) and the release protein ferroportin1 (Fpn1) in the cultured astrocytes. The effects of hepcidin on iron uptake, including transferrin‐bound iron (Tf‐Fe) and non‐transferrin‐bound iron (NTBI), and iron release were also studied. Our results demonstrated that astrocytes, when treated with hepcidin peptide or infected with hepcidin expression adenovirus (ad‐hepcidin), showed a significant ability in reducing iron uptake (both Tf‐Fe and NTBI), and iron release, which were accompanied by decreased expressions of TfR1, DMT1, and Fpn1. Moreover, we found that the effect of hepcidin in reducing TfR1 expression, which is dependent on the cyclic AMP–protein kinase A pathway, was the primary and dominant event. In conclusion, our results demonstrated that hepcidin controlled iron uptake and release by regulating expression of iron transport proteins. The findings also implied the existence of a novel hepcidin‐receptor on the membrane of astrocytes. © 2011 Wiley‐Liss, Inc.
HIV‐1 gp120 enhances outward potassium current via CXCR4 and cAMP‐dependent protein kinase a signaling in cultured rat microglia
Authors: Xu Changshui , Liu Jianuo , Chen Lina , Liang Shangdong , Fujii Nobutaka , Tamamura Hirokazu , Xiong Huangui
Published: March 2011

Microglia are critical cells in mediating the pathophysiology of neurodegenerative disorders such as HIV‐associated neurocognitive disorders. We hypothesize that HIV‐1 glycoprotein 120 (gp120) activates microglia by enhancing outward K+ currents, resulting in microglia secretion of neurotoxins, consequent neuronal dysfunction, and death. To test this hypothesis, we studied the effects of gp120 on outward K+ current in cultured rat microglia. Application of gp120 enhanced outward K+ current in a dose‐dependent manner, which was blocked by voltage‐gated K+ (Kv) channel blockers. Western blot analysis revealed that gp120 produced an elevated expression of Kv channel proteins. Examination of activation and inactivation of outward K+ currents showed that gp120 shifted membrane potentials for activation and steady‐state inactivation. The gp120‐associated enhancement of outward K+ current was blocked by either a CXCR4 receptor antagonist T140 or a specific protein kinase A (PKA) inhibitor H89, suggesting the involvement of chemokine receptor CXCR4 and PKA in gp120‐mediated enhancement of outward K+ current. Biological significance of gp120‐induced enhancement of microglia outward K+ current was demonstrated by experimental results showing the neurotoxic activity of gp120‐stimulated microglia, evaluated by TUNEL staining and MTT assay, significantly attenuated by Kv channel blockers. Taken together, these results suggest that gp120 induces microglia neurotoxic activity by enhancing microglia outward K+ current and that microglia Kv channels may function as a potential target for the development of therapeutic strategies. © 2011 Wiley‐Liss, Inc.
Levodopa and the feedback process on set‐shifting in parkinson's disease
Authors: Au Wing Lok , Zhou Juan , Palmes Paulito , Sitoh Yih‐Yian , Tan Louis CS , Rajapakse Jagath C
Published: March 2011

Objective: To study the interaction between levodopa and the feedback process on set‐shifting in Parkinson's disease (PD). Methods: Functional magnetic resonance imaging (fMRI) studies were performed on 13 PD subjects and 17 age‐matched healthy controls while they performed a modified card‐sorting task. Experimental time periods were defined based on the types of feedback provided. PD subjects underwent the fMRI experiment twice, once during “off” medication (PDoff) and again after levodopa replacement (PDon). Results: Compared with normal subjects, the cognitive processing times were prolonged in PDoff but not in PDon subjects during learning through positive outcomes. The ability to set‐shift through negative outcomes was not affected in PD subjects, even when “off” medication. Intergroup comparisons showed the lateral prefrontal cortex was deactivated in PDoff subjects during positive feedback learning, especially following internal feedback cues. The cortical activations were increased in the posterior brain regions in PDoff subjects following external feedback learning, especially when negative feedback cues were provided. Levodopa replacement did not completely restore the activation patterns in PD subjects to normal although activations in the corticostriatal loops were restored. Conclusion: PD subjects showed differential ability to set‐shift, depending on the dopamine status as well as the types of feedback cues provided. PD subjects had difficulty performing set‐shift tasks through positive outcomes when “off” medication, and showed improvement after levodopa replacement. The ability to set‐shift through negative feedback was not affected in PD subjects even when “off” medication, possibly due to compensatory changes outside the nigrostriatal dopaminergic pathway. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
Effects of attentional load on early visual processing depend on stimulus timing
Authors: Rauss Karsten , Pourtois Gilles , Vuilleumier Patrik , Schwartz Sophie
Published: March 2011

A growing number of studies suggest that early visual processing is not only affected by low‐level perceptual attributes but also by higher order cognitive factors such as attention or emotion. Using high‐density electroencephalography, we recently demonstrated that attentional load of a task at fixation reduces the response of primary visual cortex to irrelevant peripheral stimuli, as indexed by the C1 component. In the latter study, peripheral stimuli were always presented during intervals without task‐relevant stimuli. Here, we use a similar paradigm but present central task stimuli and irrelevant peripheral stimuli simultaneously while keeping all other stimulus characteristics constant. Results show that rather than to suppress responses to peripheral stimulation, high attentional load elicits higher C1 amplitudes under these conditions. These findings suggest that stimulus timing can profoundly alter the effects of attentional load on the earliest stages of processing in human visual cortex. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
Inconsistency and uncertainty of the human visual area loci following surface‐based registration: Probability and Entropy Maps
Authors: Yamamoto Hiroki , Fukunaga Masaki , Takahashi Shigeko , Mano Hiroaki , Tanaka Chuzo , Umeda Masahiro , Ejima Yoshimichi
Published: March 2011

Here we created two different multisubject maps (16 subjects) to characterize interindividual variability in the positions of human visual areas (V1, dorsal and ventral parts of V2/3, V3A, V3B, V7, LOc, MT+, and hV4 [or V4v and V8]), which were localized using fMRI and coregistered using a surface‐based method. The first is a probability map representing the degree of alignment inconsistency for each area, in which each point in space is associated with the probability affiliated with a given area. The second, a novel map termed an entropy map in which each point is associated with Shannon entropy computed from the probabilities, represents the degree of uncertainty regarding the area that resides there, and is maximal when all areas are equally probable. The overall average probability and entropy values were about 0.27 and 1.15 bits, respectively, with dependencies on the visual areas. The probability and entropy maps generated here will benefit any application which requires predictions of areas that are most likely present at an anatomical point and know the uncertainty associated with such predictions. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
Staying responsive to the world: Modality‐specific and ‐nonspecific contributions to speeded auditory, tactile, and visual stimulus detection
Authors: Langner Robert , Kellermann Thilo , Eickhoff Simon B. , Boers Frank , Chatterjee Anjan , Willmes Klaus , Sturm Walter
Published: March 2011

Sustained responsiveness to external stimulation is fundamental to many time‐critical interactions with the outside world. We used functional magnetic resonance imaging during speeded stimulus detection to identify convergent and divergent neural correlates of maintaining the readiness to respond to auditory, tactile, and visual stimuli. In addition, using a multimodal condition, we investigated the effect of making stimulus modality unpredictable. Relative to sensorimotor control tasks, all three unimodal detection tasks elicited stronger activity in the right temporo‐parietal junction, inferior frontal cortex, anterior insula, dorsal premotor cortex, and anterior cingulate cortex as well as bilateral mid‐cingulum, midbrain, brainstem, and medial cerebellum. The multimodal detection condition additionally activated left dorsal premotor cortex and bilateral precuneus. Modality‐specific modulations were confined to respective sensory areas: we found activity increases in relevant, and decreases in irrelevant sensory cortices. Our findings corroborate the modality independence of a predominantly right‐lateralized core network for maintaining an alert (i.e., highly responsive) state and extend previous results to the somatosensory modality. Monitoring multiple sensory channels appears to induce additional processing, possibly related to stimulus‐driven shifts of intermodal attention. The results further suggest that directing attention to a given sensory modality selectively enhances and suppresses sensory processing—even in simple detection tasks, which do not require inter‐ or intra‐modal selection. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
Different structural correlates for verbal memory impairment in temporal lobe epilepsy with and without mesial temporal lobe sclerosis
Authors: Mueller Susanne G. , Laxer Kenneth D. , Scanlon Cathy , Garcia Paul , McMullen William J. , Loring David W. , Meador Kimford J. , Weiner Michael W.
Published: March 2011

Objectives: Memory impairment is one of the most prominent cognitive deficits in temporal lobe epilepsy (TLE). The overall goal of this study was to explore the contribution of cortical and hippocampal (subfield) damage to impairment of auditory immediate recall (AIMrecall), auditory delayed recall (ADMrecall), and auditory delayed recognition (ADMrecog) of the Wechsler Memory Scale III (WMS‐III) in TLE with (TLE–MTS) and without hippocampal sclerosis (TLE‐no). It was hypothesized that volume loss in different subfields determines memory impairment in TLE–MTS and temporal neocortical thinning in TLE‐no. Methods: T1 whole brain and T2‐weighted hippocampal magnetic resonance imaging and WMS‐III were acquired in 22 controls, 18 TLE–MTS, and 25 TLE‐no. Hippocampal subfields were determined on the T2 image. Free surfer was used to obtain cortical thickness averages of temporal, frontal, and parietal cortical regions of interest (ROI). MANOVA and stepwise regression analysis were used to identify hippocampal subfields and cortical ROI significantly contributing to AIMrecall, ADMrecall, and ADMrecog. Results: In TLE–MTS, AIMrecall was associated with cornu ammonis 3 (CA3) and dentate (CA3&DG) and pars opercularis, ADMrecall with CA1 and pars triangularis, and ADMrecog with CA1. In TLE‐no, AIMrecall was associated with CA3&DG and fusiform gyrus (FUSI), and ADMrecall and ADMrecog were associated with FUSI. Conclusion: The study provided the evidence for different structural correlates of the verbal memory impairment in TLE–MTS and TLE‐no. In TLE–MTS, the memory impairment was mainly associated by subfield‐specific hippocampal and inferior frontal cortical damage. In TLE‐no, the impairment was associated by mesial–temporal cortical and to a lesser degree hippocampal damage. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
High‐risk human papillomavirus and cervical lymph node metastasis in patients with oropharyngeal cancer
Authors: Joo Young‐Hoon , Jung Chan‐Kwon , Sun Dong‐Il , Park Jun‐Ook , Cho Kwang‐Jae , Kim Min‐Sik
Published: March 2011

Background

The purpose of this study was to determine the role of high‐risk human papillomavirus (HPV) in lymph node metastasis and the depth of invasion in oropharyngeal cancer.

Methods

The study included patients with 90 oral carcinomas and 66 oropharyngeal carcinomas. High‐risk HPV in situ hybridization was performed to detect HPV infection.

Results

The positive rate of high‐risk HPV in situ hybridization was 15.4% (24 of 156). There was a significant difference in the fraction of positive high‐risk HPV between oral (6.7%) and oropharyngeal (27.3%) cancers (p < .000). Significant correlations were found between positive high‐risk HPV and cervical lymph node metastasis, tumor depth of invasion in patients with oropharyngeal cancer (p = .002, p = .016, respectively). There was a statistically significant association between high‐risk HPV positivity and the disease‐specific survival in patients with oropharyngeal cancer (p = .035).

Conclusion

High‐risk HPV infection was significantly related to cervical lymph node metastasis and depth of invasion in patients with oropharyngeal cancer. © 2011 Wiley Periodicals, Inc. Head Neck, 2012
Effect of complementary pathway blockade on efficacy of combination enzastaurin and rapamycin
Authors: Liu Jing , Kuo Wen‐Liang , Seiwert Tanguy Y. , Lingen Mark , Ciaccio Mark F. , Jones Richard B. , Rosner Marsha Rich , Cohen Ezra Eddy Wyssam
Published: March 2011

Background

Rapamycin is an mTOR inhibitor with preclinical efficacy in squamous cell carcinoma of the head and neck (SCCHN). However, mTOR inhibitors also increase Akt activity in SCCHN cell lines, which would promote survival and oncogenesis. Enzastaurin is an AGC kinase inhibitor with nanomolar inhibitory concentrations for Akt and protein kinase C (PKC). Moreover, Akt and PKC inhibitors have demonstrated efficacy in SCCHN.

Methods

We hypothesized that the combination of rapamycin and enzastaurin would be more effective than either agent alone.

Results

Rapamycin and enzastaurin generally inhibited putative targets in SCCHN cell lines in culture. In mice xenografted with CAL27 cells, rapamycin and enzastaurin produced growth delay. In contrast, the combination of rapamycin and enzastaurin caused regression of CAL27 tumors with evidence of inhibition of putative targets, survival, angiogenesis and proliferation.

Conclusion

These data demonstrate that the combination of rapamycin and enzastaurin disrupts critical oncogenic pathways in SCCHN and has efficacy in preclinical models. © 2011 Wiley Periodicals, Inc. Head Neck, 2011
Heme oxygenase-1–mediated autophagy protects against hepatocyte cell death and hepatic injury from infection/sepsis in mice
Authors: Carchman Evie H. , Rao Jayashree , Loughran Patricia A. , Rosengart Matthew R. , Zuckerbraun Brian S.
Published: March 2011

Adaptive responses to sepsis are necessary to prevent organ failure and death. Cellular signaling responses that limit cell death and structural damage allow a cell to withstand insult from sepsis to prevent irreversible organ dysfunction. One such protective pathway to reduce hepatocellular injury is the up-regulation of heme oxygenase-1 (HO-1) signaling. HO-1 is up-regulated in the liver in response to multiple stressors, including sepsis and lipopolysaccharide (LPS), and has been shown to limit cell death. Another recently recognized rudimentary cellular response to injury is autophagy. The aim of these investigations was to test the hypothesis that HO-1 protects against hepatocyte cell death in experimental sepsis in vivo or LPS in vitro via induction of autophagy. These data demonstrate that both HO-1 and autophagy are up-regulated in the liver after cecal ligation and puncture (CLP) in C57BL/6 mice or in primary mouse hepatocytes after treatment with LPS (100 ng/mL). CLP or LPS results in minimal hepatocyte cell death. Pharmacological inhibition of HO-1 activity using tin protoporphyrin or knockdown of HO-1 prevents the induction of autophagic signaling in these models and results in increased hepatocellular injury, apoptosis, and death. Furthermore, inhibition of autophagy using 3-methyladenine or small interfering RNA specific to VPS34, a class III phosphoinositide 3-kinase that is an upstream regulator of autophagy, resulted in hepatocyte apoptosis in vivo or in vitro. LPS induced phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK), in part, via HO-dependent signaling. Moreover, inhibition of p38 MAPK prevented CLP- or LPS-induced autophagy.

Conclusion:

Sepsis or LPS-induced autophagy protects against hepatocellular death, in part via an HO-1 p38 MAPK-dependent signaling. Further investigations are needed to elucidate how autophagic signaling prevents apoptosis and cell death. (HEPATOLOGY 2011;)
Problems faced when evaluating the bioaccumulation potential of substances under REACH
Authors: Ehrlich Gunnar , Jöhncke Ulrich , Drost Wiebke , Schulte Christoph
Published: March 2011

The identification and regulation of substances that combine persistence, bioaccumulation potential, and toxicity (“PBT” substances) is one central aspect of the European chemical legislation REACH (Registration, Evaluation, Authorisation, and Restriction of Chemicals), because these substances may elicit adverse long-term effects after release to the environment. The determination of a substance that has persistence, bioaccumulation potential, and toxicity is based on a set of distinct cutoff criteria identified in Annex XIII of the REACH regulation. Regarding the bioaccumulation potential, the evaluation is focused on the substance's bioconcentration factor as single decisive criterion. In addition, the REACH guidelines provide a selection of standardized test procedures for measuring bioconcentration factor and guidance in appraising test results. However, alternative test results like bioaccumulation factors and biomagnification as well as additional indications for a bioaccumulation potential such as trophic magnification are only allowed for supporting evidence. The currently used test systems with aquatic exposure have been demonstrated to generate reliable results for the majority of neutral, lipophilic organic substances, which facilitate clear decision-making by means of the crucial bioconcentration factor cutoff criteria of Annex XIII. However, certain substance groups such as highly hydrophobic organic substances and amphiphilic and nonlipophilic compounds are difficult to evaluate with common test strategies due to inappropriate test systems or accumulation mechanisms not based on lipophilicity. Recent scientific progress has already been made to establish alternative test systems and to refine the bioaccumulation assessment by consideration of additive accumulation mechanisms and indications. This article gives an overview on actual shortcomings in the current bioaccumulation assessment under REACH and also provides suggestions for a refinement of evaluation. Integr Environ Assess Manag 2011;7:550–558. © 2011 SETAC
Use of Bayesian belief networks for dealing with ambiguity in integrated groundwater management
Authors: Henriksen Hans Jørgen , Zorrilla-Miras Pedro , de la Hera Africa , Brugnach Marcella
Published: March 2011

In integrated groundwater management, different knowledge frames and uncertainties need to be communicated and handled explicitly. This is necessary in order to select efficient adaptive groundwater management strategies. In this connection, Bayesian belief networks allow for integration of knowledge, for engaging stakeholders and for dealing with multiple knowledge frame uncertainties. This is illustrated for the case of the Upper Guadiana Basin, Spain, where Bayesian belief networks with stakeholder involvement were used for dealing with the ambiguities related to sustainable groundwater exploitation. Integr Environ Assess Manag 2012; 8: 430–444. © SETAC
Protease‐activated receptors and myocardial infarction
Authors: Antoniak Silvio , Pawlinski Rafal , Mackman Nigel
Published: March 2011

Protease‐activated receptors (PARs) are widely expressed within the heart. They are activated by a myriad of proteases, including coagulation proteases. In vitro studies showed that activation of PAR‐1 and PAR‐2 on cardiomyocytes induced hypertrophy. In addition, PAR‐1 stimulation on cardiac fibroblasts induced proliferation. Genetic and pharmacologic approaches have been used to investigate the role of the different PARs in cardiac ischemia/reperfusion (I/R) injury. In mice and rats, PAR‐1 is reported to play a role in inflammation, infarct size, and remodeling after cardiac I/R injury. However, there are notable differences between the effect of a deficiency in PAR‐1 and inhibition of PAR‐1. For instance, inhibition of PAR‐1 reduced infarct size whereas there was no effect of a deficiency of PAR‐1. These differences maybe due to off‐target effects of the inhibitor or PAR‐4 compensation of PAR‐1 deficiency. Similarly, a deficiency of PAR‐2 was associated with reduced cardiac inflammation and improved heart function after I/R injury, whereas pharmacologic activation of PAR‐2 was found to be protective due to increased vasodilatation. These differences maybe due to different signaling responses induced by an endogenous protease versus an exogenous agonist peptide. Surprisingly, PAR‐4 deficiency resulted in increased cardiac injury and increased mortality after I/R injury. In contrast, a pharmacological study indicated that inhibition of PAR‐4 was cardioprotective. It is possible that the major cellular target of the PAR‐4 inhibitor is platelets, which have been shown to contribute to inflammation in the injured heart, whereas PAR‐4 signaling in cardiomyocytes may be protective. These discrepant results between genetic and pharmacological approaches indicate that further studies are needed to determine the role of different PARs in the injured heart. © 2011 IUBMB IUBMB Life, 63(6): 383–389, 2011
Regulation of protease‐activated receptor signaling by post‐translational modifications
Authors: Grimsey Neil , Soto Antonio G. , Trejo JoAnn
Published: March 2011

Protease‐activated receptors (PARs) are a unique family of G‐protein‐coupled receptors (GPCRs) that are irreversibly activated following proteolytic cleavage of their extracellular N‐terminus. PARs play critical functions in hemostasis, thrombosis, inflammation, embryonic development, and cancer progression. Because of the irreversible proteolytic nature of PAR activation, signaling by the receptors is tightly regulated. Three distinct processes including desensitization, internalization, and lysosomal degradation, regulate the temporal and spatial aspects of activated PAR signaling. Post‐translational modifications play a critical role in regulating each of these processes and here we review the nature of PAR post‐translational modifications and their importance in signal regulation. The PARs are activated by numerous proteases, and some can elicit distinct cellular responses, how this biased agonism is determined is unknown. Further study of the function of post‐translational modifications of the PARs will lead to a greater understanding of the physiological regulation of baised agonism and how PAR signaling is precisely controlled in different cellular contexts. © 2011 IUBMB IUBMB Life, 63(6): 403–411, 2011
Cell damage through pentose phosphate pathway in fetus fibroblast cells exposed to methyl mercury
Authors: Amoli Jamileh Salar , Barin Abbas , Ebrahimi‐Rad Mina , Sadighara Parisa
Published: March 2011

Methylmercury (MeHg) is a global pollutant that causes malformations. There has been no direct evidence for the effect of MeHg on pentose phosphate pathway (PPP). In embryonic development, PPP is much more active. This pathway produces ribose for DNA/RNA production. It is possible that one of teratogenicity mechanisms of MeHg is through PPP. The fetus fibroblast cells were incubated with different concentrations of MeHg (0.1–100 μm). A dose–response dependence was observed in MTT assay. Transketolase activity and DNA content were determined in cell exposed to MeHg. A defect at the level of DNA content was observed. This amount of DNA was highly correlated with transketolase activity (r = 0.76). This study has demonstrated that the potential teratogenic action of MeHg is through PPP. To assess the protective effects of thiamin, the infected cells were incubated with different concentrations of thiamin. The obtained results show that thiamin pyrophosphate supplementation correlated with the toxicity. This finding confirms that thiamin therapy is suitable for the prevention of MeHg toxicity. Our study provides basic data for prevention and treatment of MeHg toxicity via boosting PPP. Copyright © 2011 John Wiley & Sons, Ltd.
Proteomics in Ménière disease
Authors: Chiarella Giuseppe , Saccomanno Milena , Scumaci Domenica , Gaspari Marco , Faniello Maria Concetta , Quaresima Barbara , Di Domenico Marina , Ricciardi Carmela , Petrolo Claudio , Cassandro Claudia , Costanzo Francesco Saverio , Cuda Giovanni , Cassandro Ettore
Published: March 2011

Ménière's disease (MD) is a disorder of the inner ear characterized by an insidious onset and aspecific symptoms, such as dizziness, vertigo, tinnitus, and hearing loss, that may become very debilitating. The presence of endolymphatic hydrops is a common feature in MD patients, but the pathophysiology is still largely unknown. In this study, we have used a proteomics‐driven approach to identify potential biomarkers of MD. To this end, plasma was obtained from whole blood of 16 individuals previously diagnosed as suffering from MD and compared to plasma from healthy donors. A depletion of the highly abundant proteins (i.e., albumin, IgG, transferrin, etc.) was performed in order to enhance the chance of detection of the less represented ones, therefore reducing the noise‐background. Two‐dimensional gel electrophoresis, followed by in‐gel tryptic digestion of the selected spots and LC‐MS/MS analysis, allowed us to identify a set of proteins whose expression appears to be differentially modulated in patients versus controls. In particular: complement factor H and B, fibrinogen alpha and gamma chains, beta‐actin and pigment epithelium derived factor are over expressed; on the other hand, the levels of beta‐2 glycoprotein‐1, vitamin D binding protein and apolipoprotein‐1 are significantly decreased in the plasma of MD‐affected individuals. Even though preliminary and not necessarily linked directly to the molecular pathogenesis of the disease, our original findings suggest that a molecular signature, represented by the plasma protein profile previously described, might represent a potentially powerful, innovative and not invasive tool for early diagnosis and clinical management of MD patients. J. Cell. Physiol. 227: 308–312, 2012. © 2011 Wiley Periodicals, Inc.
Three dimensional cultures of rat liver cells using a natural self‐assembling nanoscaffold in a clinically relevant bioreactor for bioartificial liver construction
Authors: Giri Shibashish , Acikgöz Ali , Pathak Priya , Gutschker Sylvia , Kürsten Anne , Nieber Karen , Bader Augustinus
Published: March 2011

Till date, no bioartificial liver (BAL) procedure has obtained FDA approval or widespread clinical acceptance, mainly because of multifactorial limitations such as the use of microscale or undefined biomaterials, indirect and lower oxygenation levels in liver cells, short‐term undesirable functions, and a lack of 3D interaction of growth factor/cytokine signaling in liver cells. To overcome preclinical limitations, primary rat liver cells were cultured on a naturally self‐assembling peptide nanoscaffold (SAPN) in a clinically relevant bioreactor for up to 35 days, under 3D interaction with suitable growth factors and cytokine signaling agents, alone or combination (e.g., Group I: EPO, Group II: Activin A, Group III: IL‐6, Group IV: BMP‐4, Group V: BMP4 + EPO, Group VI: EPO + IL‐6, Group VII: BMP4 + IL‐6, Group VIII: Activin A + EPO, Group IX: IL‐6 + Activin A, Group X: Activin A + BMP4, Group XI: EPO + Activin A + BMP‐4 + IL‐6 + HGF, and Group XII: Control). Major liver specific functions such as albumin secretion, urea metabolism, ammonia detoxification, phase contrast microscopy, immunofluorescence of liver specific markers (Albumin and CYP3A1), mitochondrial status, glutamic oxaloacetic transaminase (GOT) activity, glutamic pyruvic transaminase (GPT) activity, and cell membrane stability by the lactate dehydrogenase (LDH) test were also examined and compared with the control over time. In addition, we examined the drug biotransformation potential of a diazepam drug in a two‐compartment model (cell matrix phase and supernatant), which is clinically important. This present study demonstrates an optimized 3D signaling/scaffolding in a preclinical BAL model, as well as preclinical drug screening for better drug development. J. Cell. Physiol. 227: 313–327, 2012. © 2011 Wiley Periodicals, Inc.
The complexity of ERK1 and ERK2 MAPKs in multiple hepatocyte fate responses
Authors: Frémin Christophe , Ezan Frédéric , Guegan Jean‐Philippe , Gailhouste Luc , Trotard Maud , Le Seyec Jacques , Rageul Julie , Theret Nathalie , Langouët Sophie , Baffet Georges
Published: March 2011

Recent reports suggest that extracellular signal‐regulated kinase (ERK1) and ERK2 mitogen‐activated protein kinases (MAPK) may direct specific biological functions under certain contexts. In this study, we investigated the role of early and sustained epidermal growth factor (EGF) stimulation on long‐term hepatocyte differentiation and the possible role of ERK1 and ERK2 in this process. We demonstrate a long‐term survival and an elevated level of differentiation up to 3 weeks. The differentiation state of hepatocytes is supported by sustained expression of aldolase B, albumin, and the detoxifying enzymes CYP1A2, 2B2, and 3A23. Similarly to freshly isolated cells, cultured hepatocytes also retain the ability to respond to 3‐methylcholanthrene (3MC) and phenobarbital (PB), two known CYP inducers. In addition, we show evidence that continuous MAPK/ERK kinase (MEK) inhibition enhances the level of differentiation. Using RNA interference approaches against ERK1 and ERK2, we demonstrate that this effect requires both ERK1 and ERK2 activity, whereas the specific ERK1 knockdown promotes cell survival and the specific ERK2 knockdown regulates cell proliferation. In conclusion, we demonstrate that early and sustained EGF stimulation greatly extends long‐term hepatocyte survival and differentiation, and that inhibition of the ERK1/2 MAPK pathway potentiates these pro‐survival/pro‐differentiation phenotypes. We clearly attest that specific ERK1 and ERK2 MAPKs determine hepatocyte survival and proliferation, respectively, whereas dual inhibition is required to stabilize a highly differentiated state. J. Cell. Physiol. 227: 59–69, 2012. © 2011 Wiley Periodicals, Inc.
Chemicals from biomass: synthesis of lactic acid by alkaline hydrothermal conversion of sorbitol
Authors: Ramírez‐López Camilo A. , Ochoa‐Gómez José R. , Gil‐Río Silvia , Gómez‐Jiménez‐Aberasturi Olga , Torrecilla‐Soria Jesús
Published: March 2011

BACKGROUND: Currently, the ‘green chemistry’ philosophy is being increasingly adopted by the chemical industry and, therefore, new production procedures of valuable chemicals from biomass‐derived raw materials are being sought. In this work, the synthesis of lactic acid from sorbitol under alkaline hydrothermal conditions is investigated by analyzing the influence on conversions and yields of temperature, NaOH/sorbitol molar ratio (MR), initial sorbitol concentration (SC) and reaction time.

RESULTS: A 100% sorbitol conversion and a maximum 39.5% yield of lactic acid on a carbon basis are obtained at 280 °C, 50 min, 1.0 mol L−1 SC and 2.0 MR. Glyceraldehyde was the only identified intermediate while formic acid, acrylic acid, acetic acid, oxalic acid and sodium carbonate were identified as over‐oxidation products, all of them in very low yields with the exception of formic acid (16% yield at a MR of 4 and 280 °C). Several plausible conversion routes of sorbitol involving dehydrations, keto‐enol tautomerisms, reverse aldol condensations, aldol condensations, Cannizzaro reactions and oxidations are proposed.

CONCLUSIONS: Considering the high number of parallel conversion routes as a consequence of high functionality of sorbitol, the 39.5% lactic acid yield obtained is a good result. Total carbon mass in all identified products only justifies, at most, 50% of that in sorbitol due to the coexistence of several conversion routes resulting in a large number of products other than lactic acid. Copyright © 2011 Society of Chemical Industry
Degradation of C.I. Acid Orange 7 by heterogeneous Fenton oxidation in combination with ultrasonic irradiation
Authors: Zhong Xin , Xiang Luojing , Royer Sebastien , Valange Sabine , Barrault Joel , Zhang Hui
Published: March 2011

BACKGROUND: A mesoporous alumina supported nanosized Fe2O3 was prepared through an original synthesis procedure and used as a heterogeneous catalyst for the Fenton process degradation of the model azo dye C.I. Acid Orange 7 enhanced by ultrasound irradiation (US/Fe2O3‐Al2O3‐meso/H2O2 system). The effect of various operating conditions was investigated, namely hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading.

RESULTS: The results indicated that the degradation of C.I. Acid Orange 7 followed a pseudo‐first‐order kinetic model. There exists an optimal hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading for decolorization. The aggregate size of the spent catalyst was reduced after dispersion in water by ultrasonic irradiation. A very low level of iron leaching was observed ranging from < 0.1 to 0.23 mg L−1. The intermediate products of C.I. Acid Orange 7 degradation were identified using gas chromatography–mass spectrometry (GC‐MS).

CONCLUSION: The optimal conditions for efficient C.I. Acid Orange 7 degradation were pH close to 3, hydrogen peroxide concentration 4 mmol L−1, catalyst loading 0.3 g L−1, and ultrasonic power 80 W. Copyright © 2011 Society of Chemical Industry
Contaminants abatement by ozone in secondary effluents. Evaluation of second‐order rate constants
Authors: Javier Rivas F. , Sagasti Jose , Encinas Angel , Gimeno Olga
Published: March 2011

BACKGROUND: The ozonation of a mixture of contaminants commonly found in secondary effluents has been carried out in an artificially contaminated secondary effluent. Competitive ozonation experiments in heterogeneous and homogeneous mode have also been carried out to determine the second‐order direct ozonation rate constants.

RESULTS: Inlet ozone concentration, alkaline conditions and addition of 10−3 mol L−1 of H2O2 positively affected the degree of mineralization and the disappearance of chemical oxygen demand of the mixture. Reaction rates depend on pH; at pH 7 the following direct ozone rate constants were obtained: 2.7 × 105, 2.5 × 103, 2.5 × 104, 6.2 × 105, 3.2 × 105, 3.4 × 105, 8.0 × 105 and 4.6 × 105 mol−1 L1 s−1 for acetaminophen, metoprolol, caffeine, antipyrine, norfloxacin, ketorolac, doxycycline, hydroxybiphenyl, and diclofenac, respectively.

CONCLUSIONS: The positive effect on TOC and COD removal that ozone dosage exerts is not applicable to individual contaminants. An optimum ozone concentration can be found with no further improvement of the depletion rate of organics as the ozone inlet concentration is increased. Carbonates affect the oxidation of recalcitrant compounds like atrazine. Carbonate concentration must be considered when dealing with real effluents. Addition of hydrogen peroxide can increase the mineralization level obtained, however the increase in complexity and costs does not justify its addition. Copyright © 2011 Society of Chemical Industry
Activated sludge process coupled with intermittent ozonation for sludge yield reduction and effluent water quality control
Authors: Järvik Oliver , Viiroja Andres , Kamenev Sven , Kamenev Inna
Published: March 2011

BACKGROUND: Ozone is applied in wastewater treatment for effluent water quality improvement (post‐ozonation) as well as for excess sludge reduction (in the recirculation line). There is some evidence that ozone dosed directly to aerobic biooxidation (ABO) process enhances degradation of recalcitrant compounds into intermediates, following their biodegradation in the same reactor. However, no information regarding the influence of ozone on sludge yield in this system was found. Therefore, the current work aimed to evaluate the effect of ozone on the sludge yield when ozone is dosed directly to the ABO process. In addition, batch and continuous treatment schemes for phenolic wastewater treatment are compared.

RESULTS: The results revealed that an optimal ozone dose of ∼30 mgO3 L−1 day−1 reduced the sludge yield by ∼50%, while effluent water quality in terms of total chemical oxygen demand (TCOD), compared with a conventional ABO process, was improved by 35.5 ± 3.6%. Slight improvement in soluble COD removal at the same ozone dose was also detected. The toxicity of effluent water was reduced as the ozone dose was increased.

CONCLUSIONS: In an integrated ozonation‐ABO process it is possible to simultaneously reduce sludge yield and to improve effluent water quality, as COD and toxicity are reduced. Copyright © 2011 Society of Chemical Industry
Effect of B‐site cation on the catalytic activity of La1−xCaxBO3 (B = Fe, Ni) perovskite‐type oxides for toluene combustion
Authors: Pecchi G. , Jiliberto M.G. , Delgado E.J. , Cadús L.E. , Fierro J.L.G.
Published: March 2011

Background The effect of the B cation on the surface properties and catalytic activity in the total combustion of toluene over La1−xCaxBO3 (B = Fe,Ni) perovskite‐type oxides was studied.

Result For the La1−xCaxFeO3 series, the perovskite structure was maintained in the range of substitution studied. A completely different behaviour was observed for the La1−xCaxNiO3 series. A Brownmillerite‐type structure (La2Ni2O5) with a large degree of phase segregation as well dispersed mixed oxides was observed upon the substitution of La for Ca. In the Fe series, the catalytic activity in the total combustion of toluene showed that the insertion of calcium ions into the perovskite lattice resulted in higher activity relative to the unsubstituted LaFeO3 perovskite. In contrast, for the Ni series, substitution results in solids with lower activity than the pure LaNiO3 perovskite.

Conclusion For the Fe series, higher activity and stability are attributed to a synergy between Fe4+/Fe3+ and the oxygen vacancies generated by the calcium substitution. For the Ni counterpart, the structural modification leads to a lower activity of substituted solids compared with the pure LaNiO3 perovskite, indicating that Ni3+ ions are the active sites for toluene oxidation. Copyright © 2011 Society of Chemical Industry
The response of filamentous fungus Rhizopus nigricans to flavonoids
Authors: Slana Marko , Žigon Dušan , Makovec Tomaž , Lenasi Helena
Published: March 2011

The saprophytic fungus Rhizopus nigricans constitutes a serious problem when thriving on gathered crops. The identification of any compounds, especially natural ones, that inhibit fungal growth, may therefore be important. During its life cycle, Rhizopus nigricans encounters many compounds, among them the flavonoids, plant secondary metabolites that are involved in plant defense against pathogenic microorganisms. Although not being a plant pathogen, Rhizopus nigricans may interact with these compounds in the same way as plant pathogens – in response to the fungitoxic effect of flavonoids the fungi transform them into less toxic metabolites. We have studied the interaction of R. nigricans with some flavonoids. Inhibition of hyphal spreading (from 3% to 100%) was observed by 300 μM flavones, flavanones and isoflavones, irrespective of their basic structure, oxidized or reduced C‐ring, and orientation of the B‐ring. However, a hydrophobic A‐ring was important for the toxicity. R. nigricans transformed some of the flavonoids into glucosylated products. Recognition of substrates for glucosylating enzyme(s) did not correlate with their fungitoxic effect but depended exclusively on the presence of a free –OH group in the flavonoid A‐ring and of a hydrophobic B‐ring. Although the fungus produced glucosyltransferase constitutively, an additional amount of the enzyme was induced by the substrate flavonoid. Moreover, effective detoxification was shown to require the presence of glucose. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Purification, characterization and thermodynamics of antifungal protease from Streptomyces sp. A6
Authors: Singh Anil Kumar , Chhatpar Hari S.
Published: March 2011

A 20 kDa antifungal serine protease from Streptomyces sp. A6 was purified to 34.56 folds by gel permeation chromatography. The enzyme exhibited highest activity at neutral to near alka‐ line pH 7–9 and 55 °C. Neutral surfactant triton X‐100 enhanced the activity by 4.12 fold. The protease activity also increased (109.9–119%) with increasing concentration of urea (2–8 mole/l). The enzyme was identified as serine protease with 67% similarity to SFase 2 of Streptomyces fradiae by MALDI‐LC‐MS/MS analysis. Determination of kinetic constants km, Vmax, kcat and kcat/km suggested higher affinity of enzyme for N‐Suc‐Ala‐Ala‐Val‐Ala‐p NA (synthetic substrate for chymotrypsin activity). The enzyme was highly stable at temperature prevailing under field conditions (40 °C) as apparent from Kd and t1/2 values, 0.0065 and 106.75 min, respectively and high ΔG* and negative ΔS * values, 87.17 KJ/mole and –126.95 J/mole, respectively. Thermal stability and increased activity of protease in presence of commonly used chemical fertilizer, urea, suggested its feasibility for agricultural applications. The present study is the first report on thermodynamic and kinetic properties of an antifungal protease from Streptomyces sp. A6. The study reflects potential of this enzyme for biocontrol of fungal plant pathogens. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rhamnolipid from Pseudomonas desmolyticum NCIM‐2112 and its role in the degradation of Brown 3REL
Authors: Jadhav Mital , Kalme Satish , Tamboli Dhawal , Govindwar Sanjay
Published: March 2011

The biosurfactant produced by Pseudomonas desmolyticum NCIM 2112 (Pd 2112) was confirmed as rhamnolipid based on the formation of dark blue halos around the colonies in CTAB‐methylene blue agar plates and the content of rhamnose sugar. The average yield of rhamnolipid was 0.398 g/l/day when grown on hexadecane as sole carbon source. Pd 2112 emulsification potential associated with cell free culture broth was stable for 72 h using various hydrocarbons and vegetable oils. Chemical structure of the biosurfactant was identified as mono‐rhamnolipid (Rha‐C6–C8) using HPTLC, fourier transform infrared spectroscopy, 1H and 13C NMR and gas chromatography‐mass spectroscopy analysis. Pd 2112 mono‐rhamnolipid (1 mg/ml) had in‐creased permeabilization of Bacillus sp VUS NCIM 5342 and increased decolorization rate of textile dye Brown 3REL by 50%. Extracellular activities of lignin peroxidase and veratryl alcohol oxidase, enzymes involved in dye degradation, were significantly increased in the presence of mono‐rhamnolipid by 324.52% and 100% respectively. Scanning electron micro‐scopy observations revealed that rhamnolipid did not exert any disruptive action on Bacillus cells as compared to Tween 80. The mono‐rhamnolipid of Pd 2112 has potential for its application in biodegradation of textile dyes. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A study on significant microbial interaction leading to decolorization and degradation of textile dye Rubine 3GP
Authors: Phugare Swapnil S. , Kagalkar Anuradha N. , Govindwar Sanjay P. , Jadhav Jyoti P.
Published: March 2011

The present study evaluates an obligatory interaction between the yeast Saccharomyces cerevisiae NCIM 3312 and the bacterium Pseudomonas sp. strain BCH3 for the biodegradation of the dye Rubin 3GP (R3GP). No significant degradation of R3GP was observed either by Saccharomyces cerevisiae NCIM 3312 or by Pseudomonas sp. strain BCH3, when both the cultures were tested individually under their respective optimum medium conditions. However, when both of them were allowed to intermingle with each other, R3GP was found to be degraded within 72 h, with a steady increase in β ‐1,3‐glucanase, chitinase and protease activity in the culture supernatant; indicating the possible role of Pseudomonas sp. strain BCH3 in cell wall lysis of S. cerevisiae NCIM 3312. The present study elucidates a rare microbial interaction where the bacterium Pseu‐domonas sp. strain BCH3 utilizes lysed yeast cells as the sole source of nutrients for its own growth and subsequently performs decolorization and degradation of R3GP. Enzymatic status showed involvement of various oxidoreductive enzymes like lignin peroxidase, laccase, DCIP reductase and azo reductase, indicating their role in decolorization and degradation of R3GP. Degradation was confirmed using HPLC, FTIR analysis and the biochemical pathway of degradation was elucidated by using GC‐MS analysis. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)