bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuromagnetic functional coupling during dichotic listening of speech sounds
Authors: Brancucci Alfredo , Penna Stefania Della , Babiloni Claudio , Vecchio Fabrizio , Capotosto Paolo , Rossi Davide , Franciotti Raffaella , Torquati Kathya , Pizzella Vittorio , Rossini Paolo M. , Romani Gian Luca
Published: March 2007

The present magnetoencephalography (MEG) study tested the hypothesis of a phase synchronization (functional coupling) of cortical alpha rhythms (about 6–12 Hz) within a “speech” cortical neural network comprising bilateral primary auditory cortex and Wernicke's areas, during dichotic listening (DL) of consonant‐vowel (CV) syllables. Dichotic stimulation was done with the CV‐syllable pairs /da/‐/ba/ (true DL, yielded by stimuli having high spectral overlap) and /da/‐/ka/ (sham DL, obtained with stimuli having poor spectral overlap). Whole‐head MEG activity (165 sensors) was recorded from 10 healthy right‐handed non‐musicians showing right ear advantage in a speech DL task. Functional coupling of alpha rhythms was defined as the spectral coherence at the following bands: alpha 1 (about 6–8 Hz), alpha 2 (about 8–10 Hz), and alpha 3 (about 10–12) with respect to the peak of individual alpha frequency. Results showed an inverse pattern of functional coupling: during DL of speech sounds, spectral coherence of the high‐band alpha rhythms increased between left auditory and Wernicke's areas with respect to sham DL, whereas it decreased between left and right auditory areas. The increase of functional coupling within the left hemisphere would underlie the processing of the syllable presented to the right ear, which arrives to the left auditory cortex without the interference of the other syllable presented to the left ear. Conversely, the decrease of inter‐hemispherical coupling of the high‐band alpha might be due to the fact that the two auditory cortices do not receive the same information from the ears during DL. These results suggest that functional coupling of alpha rhythms can constitute a neural substrate for the lateralization of auditory stimuli during DL. Hum Brain Mapp 2008. © 2007 Wiley‐Liss, Inc.
Breast cancer associated transcriptional repressor PLU‐1/JARID1B interacts directly with histone deacetylases
Authors: Barrett Angela , Santangelo Samantha , Tan Keith , Catchpole Steve , Roberts Kevin , Spencer‐Dene Bradley , Hall Debbie , Scibetta Angelo , Burchell Joy , Verdin Eric , Freemont Paul , Taylor‐Papadimitriou Joyce
Published: March 2007

The PLU‐1/JARID1B nuclear protein, which is expressed in a high proportion of breast cancers, but shows restricted expression elsewhere, belongs to the ARID family of proteins, known to play important roles in development, differentiation, transcriptional regulation and chromatin remodeling. PLU‐1/JARID1B is a strong transcriptional repressor, and here we show that the protein localizes in MAD bodies when cotransfected with class IIa histone deacetylases (HDACs) or N‐CoR. Direct binding to class I and class IIa HDACs is demonstrated, while the interaction with N‐CoR appears to be indirect. The domains involved in the HDAC4‐PLU‐1/JARID1B interaction were investigated in detail, and the data show that 2 PHD domains in PLU‐1/JARID1B, which are involved in transcriptional repression, are also crucial for binding to a domain in the 5′ region of HDAC4, overlapping the MEF‐2 binding region. Physiological relevance of this interaction in the mammary gland is suggested from the observation that HDAC4 and PLU‐1/JARID1B are coexpressed in the pregnant and involuting mouse mammary gland and are both silenced at lactation. Significantly, the expression of both proteins is seen in breast cancers. © 2007 Wiley‐Liss, Inc.
Mutations of the Wnt antagonist AXIN2 (Conductin) result in TCF‐dependent transcription in medulloblastomas
Authors: Koch Arend , Hrychyk Aksana , Hartmann Wolfgang , Waha Anke , Mikeska Thomas , Waha Andreas , Schüller Ulrich , Sörensen Nils , Berthold Frank , Goodyer Cynthia G. , Wiestler Otmar D. , Birchmeier Walter , Behrens Jürgen , Pietsch Torsten
Published: March 2007

Medulloblastomas (MBs) represent the most common malignant brain tumors in children. Most MBs develop sporadically in the cerebellum, but their incidence is highly elevated in patients with familial adenomatous polyposis coli. These patients carry germline mutations in the APC tumor suppressor gene. APC is part of a multiprotein complex involved in the Wnt signaling pathway that controls the stability of β‐catenin, the central effector in this cascade. Previous genetic studies in MBs have identified mutations in genes coding for β‐catenin and its partners, APC and AXIN1, which cause activation of Wnt signaling. The pathway is negatively controlled by the tumor suppressor AXIN2 (Conductin), a scaffold protein of this signaling complex. To investigate whether alterations in AXIN2 may also be involved in the pathogenesis of sporadic MBs, we performed a mutational screening of the AXIN2 gene in 116 MB biopsy samples and 11 MB cell lines using single‐strand conformation polymorphism and sequencing analysis. One MB displayed a somatic, tumor‐specific 2 bp insertion in exon 5, leading to carboxy‐terminal truncation of the AXIN2 protein. This tumor biopsy showed nuclear accumulation of β‐catenin protein, indicating an activation of Wnt signaling. In 2 further MB biopsies, mutations were identified in exon 5 (Glu408Lys) and exon 8 (Ser738Phe) of the AXIN2 gene, which are due to predicted germline mutations and rare polymorphisms. mRNA expression analysis in 22 MBs revealed reduced expression of AXIN2 mRNA compared to 8 fetal cerebellar tissues. Promoter hypermethylation could be ruled out as a major cause for transcriptional silencing by bisulfite sequencing. To study the functional role of AXIN2 in MBs, wild‐type AXIN2 was overexpressed in MB cell lines in which the Wnt signaling pathway was activated by Wnt‐3a. In this assay, AXIN2 inhibited Wnt signaling demonstrated in luciferase reporter assays. In contrast, overexpression of mutated AXIN2 with a deleted C‐terminal DIX‐domain resulted in an activation of the Wnt signaling pathway. These findings indicate that mutations of AXIN2 can lead to an oncogenic activation of the Wnt pathway in MBs. © 2007 Wiley‐Liss, Inc.
Improved detection of bladder carcinoma cells in voided urine by standardized microsatellite analysis
Authors: Frigerio Simona , Padberg Barbara C. , Strebel Räto T. , Lenggenhager Daniela M. , Messthaler Angelika , Abdou Marie‐Therese , Moch Holger , Zimmermann Dieter R.
Published: March 2007

Successful treatment of bladder cancer depends largely on early diagnosis of primary and recurrent disease. Sensitive, specific and noninvasive procedures for detection are especially needed for grade 1 and 2 bladder tumors, because of the relatively low sensitivity of cytology. Here we introduce a novel strategy to improve the sensitivity and reliability of microsatellite analyses by employing marker‐specific threshold values for loss‐of‐heterozygosity (LOH) at 10 loci. These individual cut‐offs were experimentally determined with 35 normal control tissues and subsequently validated in a retrospective study with bladder cancer biopsies from 86 patients. In a prospective analysis of voided urines samples and matched blood probes from 91 patients, LOH‐analysis, UroVysion FISH and conventional urine cytology were compared with histological findings of consecutive transurethral biopsies. Whereas all samples could be analyzed by our LOH assay, only 56 samples were suitable for all 3 analyses. The highest sensitivity was obtained with our LOH‐assay/cytology approach (G1–2: 72%; G3: 96%) being only surpassed by a combination of all 3 techniques (G1–2: 83%; G3: 100%). Since over 93% of the patients with recurrent disease were identified by LOH/cytology‐analyses of their voided urine samples, a monitoring scheme alternating cystoscopy with LOH/cytology‐examination could now be envisioned to reduce invasive interventions and consequently improve follow‐up compliance, especially in patients with low grade tumors. © 2007 Wiley‐Liss, Inc.
TNF potentiates anticancer activity of bortezomib (Velcade®) through reduced expression of proteasome subunits and dysregulation of unfolded protein response
Authors: Nowis Dominika , McConnell Elizabeth J. , Dierlam Lindsey , Palamarchuk Alla , Lass Agnieszka , Wójcik Cezary
Published: March 2007

Bortezomib (Velcade®) exploits proteasome inhibition as a unique mechanism of anticancer activity. The effectiveness of bortezomib is, however, limited, therefore, the search for therapeutic regimens combining bortezomib with other agents. In the present work we demonstrate enhanced anticancer activity of bortezomib by its combination with tumor necrosis factor (TNF) in the experimental model of C‐26 colon carcinoma in mice. This interaction likely relies on the induction of a dysregulated response to ER stress, leading to apoptosis of cancer cells, evidenced by caspase‐3 cleavage, p53 accumulation as well as increased SAPK/JNK phosphorylation. ER stress induced by the combination of TNF and bortezomib is corroborated by upregulation of BiP, PDI and calnexin as well as cleavage of caspase‐12; however, in contrast to the classic pathway, it is also associated with decreased phosphorylation of eIF2α and prevention of XBP‐1 splicing. TNF prevented the upregulation of Hsp27 induced by bortezomib, which may contribute to enhanced ER stress. Moreover, TNF interfered with bortezomib‐induced upregulation of distinct subunits of the 26S proteasome. Bortezomib concentration used in this study was not sufficient to prevent TNF from inducing nuclear translocation of p65/RelA; however, the combination of both agents reduced total p65/RelA levels. Combined treatment of tumor‐bearing mice with bortezomib and TNF not only inhibited tumor growth but also significantly prolonged animal survival. Therefore, combination of bortezomib with TNF is an attractive option for further clinical studies. © 2007 Wiley‐Liss, Inc.
δ‐, but not µ‐, opioid receptor stabilizes K+ homeostasis by reducing Ca2+ influx in the cortex during acute hypoxia
Authors: Chao Dongman , Bazzy‐Asaad Alia , Balboni Gianfranco , Xia Ying
Published: March 2007

Past work has shown that δ‐opioid receptor (DOR) activation by [D‐Ala2,D‐Leu5]‐enkephalin (DADLE) attenuated the disruption of K+ homeostasis induced by hypoxia or oxygen‐glucose deprivation (OGD) in the cortex, while naltrindole, a DOR antagonist blocked this effect, suggesting that DOR activity stabilizes K+ homeostasis in the cortex during hypoxic/ischemic stress. However, several important issues remain unclear regarding this new observation, especially the difference between DOR and other opioid receptors in the stabilization of K+ homeostasis and the underlying mechanism. In this study, we asked whether DOR is different from µ‐opioid receptors (MOR) in stabilizing K+ homeostasis and which membrane channel(s) is critically involved in the DOR effect. The main findings are that (1) similar to DADLE (10 µM), H‐Dmt‐Tic‐NH‐CH (CH2COOH)‐Bid (1–10 µM), a more specific and potent DOR agonist significantly attenuated anoxic K+ derangement in cortical slice; (2) [D‐Ala2, N‐Me‐Phe4, glycinol5]‐enkephalin (DAGO; 10 µM), a MOR agonist, did not produce any appreciable change in anoxic disruption of K+ homeostasis; (3) absence of Ca2+ greatly attenuated anoxic K+ derangement; (4) inhibition of Ca2+‐activated K+ (BK) channels with paxilline (10 µM) reduced anoxic K+ derangement; (5) DADLE (10 µM) could not further reduce anoxic K+ derangement in the Ca2+‐free perfused slices or in the presence of paxilline; and (6) glybenclamide (20 µM), a KATP channel blocker, decreased anoxia‐induced K+ derangement, but DADLE (10 µM) could further attenuate anoxic K+ derangement in the glybenclamide‐perfused slices. These data suggest that DOR, but not MOR, activation is protective against anoxic K+ derangement in the cortex, at least partially via an inhibition of hypoxia‐induced increase in Ca2+ entry‐BK channel activity. J. Cell. Physiol. 212: 60–67, 2007. © 2007 Wiley‐Liss, Inc.
Cyclin B1 proteolysis via p38 MAPK signaling participates in G2 checkpoint elicited by arsenite
Authors: Li Ju‐Pi , Yang Jia‐Ling
Published: March 2007

Timely induction of cyclin B1 controls mitotic entry, whereas its proteolysis is essential for mitotic exit. By contrast, cyclin B1 transcription is repressed during G2 arrest induced by DNA damage. The p38 mitogen‐activated protein kinase is involved in the G2 checkpoint; yet, its impact on cyclin B1 protein levels remains unclear. Here we show that untimely proteolysis of cyclin B1 following p38 activation contributes to G2 checkpoint. Exposing early G2 cells to arsenite impeded cyclin B1 protein accumulation, Cdk1 activation, and G2‐to‐M progression. Conversely, cyclin B1 was non‐degradable in late G2 and mitotic cells after arsenite. Cyclin B1 proteolysis was enhanced by arsenite in early G2 and asynchronous cells. This rapid destruction of cyclin B1 was mediated via the ubiquitin–proteasome pathway probably in a Cdc20 and Cdh1 independent mechanism. Under arsenite, inhibition of p38 activation or depletion of p38α suppressed cyclin B1 ubiquitination and proteolysis, while forced expression of MKK6‐p38 accelerated these events. Inactivation of p38 in arsenite‐treated early G2 cells allowed G2‐to‐M progression, blocked apoptosis, increased cell viability, and decreased micronucleus formation. Thus, p38 signaling pathway triggering cyclin B1 proteolysis after arsenite may play an important role in connecting G2 arrest with apoptosis or genome instability. J. Cell. Physiol. 212: 481–488, 2007. © 2007 Wiley‐Liss, Inc.
Morphological and chemical studies of pathological human and mice brain at the subcellular level: Correlation between light, electron, and nanosims microscopies
Authors: Quintana Carmen , Wu Ting‐Di , Delatour Benoit , Dhenain Marc , Guerquin‐Kern Jean luc , Croisy Alain
Published: March 2007

Neurodegenerative diseases induce morphological and chemical alterations in well‐characterized regions of the brain. Understanding their pathological processes requires the use of methods that assess both morphological and chemical alterations in the tissues. In the past, microprobe approaches such as scanning electron microscopy combined with an X‐ray spectrometer, Proton induced X‐ray emission, secondary ion mass spectrometry (SIMS), and laser microprobe mass analysis have been used for the study of pathological human brain with limited success. At the present, new SIMS instruments have been developed, such as the NanoSIMS‐50™ ion microprobe, that allow the simultaneous identification of five elements with high sensitivity, at subcellular spatial resolution (about 50–100 nm with the Cs+ source and about 150–200 nm with O− source). Working in scanning mode, 2D distribution of five elements (elemental maps) can be obtained, thus providing their exact colocalization. The analysis can be performed on semithin or ultrathin embedded sections. The possibility of using transmission electron microscopy and SIMS on the same ultrathin sections allows the correlation between structural and analytical observations at subcellular and ultrastructural level to be established. Our observations on pathological brain areas allow us to establish that the NanoSIMS‐50 ion microprobe is a highly useful instrument for the imaging of the morphological and chemical alterations that take place in these brain areas. In the human brain our results put forward the subcellular distribution of iron–ferritin–hemosiderin in the hippocampus of Alzheimer disease patients. In the thalamus of transgenic mice, our results have shown the presence of Ca–Fe mineralized amyloid deposits. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Relationships between various functional, thermal and pasting properties of flours from different Indian black gram (Phaseolus mungo L.) cultivars
Authors: Kaur Maninder , Singh Narpinder
Published: March 2007

Flours from different black gram cultivars were investigated for functional, thermal and pasting properties and related to each other using Pearson correlations and principal component analysis (PCA). Ash, fat, protein content and bulk density of flours ranged between 25.7 and 32.5, 5.2 and 10.2, 220 and 289 g kg−1 and 519 and 563 kg m−3, respectively. The water absorption capacity (WAC) and oil absorption capacity (OAC) of flours ranged between 2390 and 3450, and 1130 and 1700 g kg−1, respectively. Least gelation concentration (LGC) for various black gram flours ranged between 8 and 12%, thereby suggesting their good gelating ability. The results showed that the foams produced by black gram flours were relatively thick with low foaming capacity (36.2–49.2%) and foam stability > 90% after 120 min of storage. The transition temperatures (To, Tp and Tc) and enthalpy of gelatinization (ΔHgel) determined using differential scanning calorimeter, ranged between 71.0 and 75.7, 76.1 and 80.4, 81.9 and 86.0 °C, and 3.08 and 3.67 J g−1, respectively. Pasting temperature, peak‐, breakdown‐, final‐ and setback viscosity were between 68.9 and 81.1 °C, 2988 and 3699, 1200 and 1730, 2839 and 3520, and 1110 and 1474 mPa s, respectively. PCA showed that UG‐218 and UG‐1008 flours were located at the far left of the score plot with a large negative score, while the KU‐3 and UG‐1017 flours had a large positive score in the first principal component (PC1). Overall, these flours differed to the greatest degree in terms of the properties of their flours. Several significant correlations between functional, thermal and pasting properties were revealed both by Pearson correlation and PCA. Copyright © 2007 Society of Chemical Industry
Concentration of indoles and other rumen metabolites in sheep after a meal of fresh white clover, perennial ryegrass or Lotus corniculatus and the appearance of indoles in the blood
Authors: Schreurs Nicola M , Marotti Danielle M , Tavendale Michael H , Lane Geoffrey A , Barry Tom N , López‐Villalobos Nicolas , McNabb Warren C
Published: March 2007

The objective of this study was to determine the effect of feeding three fresh forage diets, white clover (WC), perennial ryegrass (PRG) and Lotus corniculatus (LC), on the formation of indole and skatole in the rumen of sheep. The formation of indole and skatole in the rumen and their appearance in the blood were also compared. Peak rumen indole and skatole concentrations per kg crude protein intake (CPI) were significantly higher when feeding WC compared with PRG and LC (P < 0.05) and this was associated with a significantly higher rumen concentration per kg CPI of ammonia, branched chain volatile fatty acids, total nitrogen and soluble nitrogen (P < 0.05). Greater indole and skatole concentrations when feeding WC can be attributed to high solubility and rapid degradation of the forage protein. LC had a similar nutrient composition to WC, but the condensed tannins in LC slowed protein degradation and reduced indole and skatole formation. Indole and skatole concentrations peaked in the plasma 1–2 h after the end of feeding, indicating that skatole and indole are rapidly absorbed from the rumen into the blood. High indole and skatole formation with low intakes of WC indicates that the WC component of traditional New Zealand pastures may be the primary cause of undesirable pastoral flavours that result from the presence of indoles in meat. To ameliorate undesirable flavours, producers reliant on pastoral systems will need to consider using alternative forages such as LC to reduce protein solubility and degradation rate. Copyright © 2007 Society of Chemical Industry
Variation of organic carbon and nitrogen in aggregate size fractions of a paddy soil under fertilisation practices from Tai Lake Region, China
Authors: Li Lianqing , Zhang Xuhui , Zhang Pingjiu , Zheng Jufeng , Pan Genxing
Published: March 2007

Long‐term changes in agricultural management can affect soil organic carbon (SOC) and nutrient dynamics, which can be monitored by determining the distribution of microbial activity and nutrient pools in soil aggregates of different size fractions. The objective of the present study was to investigate the changes in SOC and total nitrogen (Nt) distribution in aggregates of different size fractions from a paddy soil (Ferric‐accumulic Stagnic Anthrosols) under a long‐term fertilisation trial. Undisturbed samples of topsoil (0–5 and 5–15 cm depths) were collected from a field experiment farm located in Tai Lake Region, China, with the plots receiving no fertiliser (NF), chemical fertilisers (CF), chemical fertilisers with straw return (CFS) or chemical fertilisers plus pig manure (CFM). In the surface layer, SOC and Nt concentrations appeared as a bimodal peak in the 2000–250 and < 2 µm fractions. SOC concentration increased by 38.6, 40.8 and 17.2% and Nt concentration by 30.0, 16.8 and 38.4% in the 2000–250 µm fractions under CFM, CFS and CF respectively as compared with NF treatment. There were slight changes in SOC and Nt in the < 2 µm fractions from different fertilisation plots. Continuous addition of manure or straw increased storage of SOC and Nt mainly in the coarser aggregate fractions. SOC increases due to straw or pig manure application predominated in the 2000–250 µm fractions, with SOC seeming to be physically protected within macro‐aggregates. Thus straw and manure are likely to play an important role in carbon and nitrogen storage in paddy soil under long‐term combined chemical and organic fertilisation. Copyright © 2007 Society of Chemical Industry
Effect of calcium chloride on mechanical properties and microbiological characteristics of cv. Conservolea naturally black olives fermented at different sodium chloride levels
Authors: Tassou Chrysoula C , Katsaboxakis Constantinos Z , Georget Dominique MR , Parker Mary L , Waldron Keith W , Smith Andrew C , Panagou Efstathios Z
Published: March 2007

The effect of calcium chloride (CaCl2)(5 gL−1) and sodium chloride (NaCl) concentration (40, 60 and 8 gL−1) on the microbiological and mechanical properties of naturally black olives of cv. Conservolea in brines was studied. In 40 and 60 g L−1 brines the growth of lactic acid bacteria was favoured over that of yeasts, resulting in rather complete lactic acid fermentation as indicated by high free acidity (9.8–11.5 g lactic acid L−1) and low pH (3.7–3.8). At 80 g L−1 brine, yeasts were the dominant members of the microflora, rendering a product with lower acidity (8 g lactic acid L−1) and higher pH (4.3–4.5). In the presence of CaCl2 there was a consistent increase in the depth of the peripheral region in which cell wall breakage occurred. When cells separated, perforated walls were observed at sites associated with plasmodesmata. The flesh was strongest and stiffest when CaCl2 was added to olives treated with 40 g L−1 brine, consistent with cell wall breakage being the predominant mode of failure. The only observed effect on the mechanical properties of the skin was a stiffening at 60 g L−1 brine on addition of CaCl2. Copyright © 2007 Society of Chemical Industry
Influence of postharvest UV‐C treatment on refrigerated storage of minimally processed broccoli (Brassica oleracea var. Italica)
Authors: Lemoine Maria L , Civello Pedro M , Martínez Gustavo A , Chaves Alicia R
Published: March 2007

Minimally processed broccoli was treated with UV‐C light (8 kJ m−2) and subsequently stored for 21 days at 4 °C. The UV‐C treatment delayed yellowing and chlorophyll degradation during storage. Treated broccoli florets displayed lower electrolyte leakage and respiratory activity, indicating higher tissue integrity. Treated samples showed higher phenolic and ascorbic acid contents as well as higher antioxidant activity than controls. Treated samples also had a higher content of soluble sugars, but no differences in the content of soluble proteins between control and treated samples were detected. The UV‐C treatment also affected bacterial and mould populations. After 21 days at 4 °C the number of colony‐forming units of both populations was lower in treated than in control broccoli florets. The results suggest that UV‐C treatment reduces tissue damage of minimally processed broccoli during storage at 4 °C, thus maintaining nutritional quality and reducing microbial growth. Copyright © 2007 Society of Chemical Industry
Inhibitory effect of phenolics extracted from sorghum genotypes on Aspergillus parasiticus (NRRL 2999) growth and aflatoxin production
Authors: Ratnavathi CV , Sashidhar RB
Published: March 2007

The inhibitory activity of bioactive polyphenols present in six sorghum genotypes—two red (AON 486 and IS 620), two yellow (LPJ and IS 17779) and two white (SPV 86 and SPV 462) varieties—on Aspergillus parasiticus (NRRL 2999) growth and aflatoxin production was evaluated. In the first experiment the production of aflatoxins in the six sorghum genotypes after removal of surface phenolics by acidic methanol treatment was studied and compared with that in untreated grains. Aflatoxin production was found to be fourfold higher in treated grains. The total phenols and bioactive polyphenols extracted by acidic methanol were quantified using the Folin–Denis method and the bovine serum albumin–benzidine conjugate procedure respectively. In the second experiment the effect of extracted sorghum phenolics under in vitro conditions on fungal growth and aflatoxin production was studied at two concentrations (0.01% and 0.1%) of phenolics. Extracted phenolics added to yeast extract sucrose (YES) medium at 0.1% concentration showed an inhibitory effect on aflatoxin production. At 0.01% phenolic concentration, aflatoxin production was minimal on day 3 after infection. At other time points the aflatoxin content was similar to that in the control. At 9 days after infection the fungal biomass in IS 620 was significantly lower than that in the control. At 0.1% phenolic concentration, aflatoxin production was minimal and the red genotype IS 620 showed maximum resistance. Fungal biomass was lowest at all growth stages in IS 620 as compared with the control. Polyphenol oxidase (PPO) activity was not detected in A. parasiticus grown on YES medium (control). PPO activity was not induced in A. parasiticus by the addition of phenolics to the liquid culture medium (no PPO activity was detected in the culture medium). The inhibitory activity of bioactive polyphenols could be attributed to the lack of PPO enzyme in this fungus. Copyright © 2007 Society of Chemical Industry
Effect of terroir on the volatiles of Vitis vinifera cv. Albariño
Authors: Vilanova Mar , Zamuz Sol , Vilariño Fernando , Sieiro Carmen
Published: March 2007

The effect of terroir on volatiles of Vitis vinifera cv Albariño was studied. Twelve commercial Albariño wines from Galicia, Spain, were analysed. The content of varietals and fermentative volatile compounds was determined by gas chromatography. The numerous significant differences found for most of the aromatic compounds studied show the influence of the terroir. The Albariño wines from northern Galicia showed the highest total concentration of volatiles analysed. The volatile components showing the greatest differences in Albariño wines from different areas were terpenes and higher alcohols. Among the terpenes found, geraniol was markedly abundant in the north, while nerol and linalool were most abundant in the south. Among the alcohols, 2‐phenyl ethanol and benzyl alcohol showed the highest concentrations in the south and in the north, respectively. Cluster analysis and principal component analysis revealed two clearly defined main groups of Albariño wines from different terroirs. Albariño wines from the south were more heterogenic than those of the north. Copyright © 2007 Society of Chemical Industry
Rebuilding gluten network of damaged wheat by means of glucose oxidase treatment
Authors: Bonet Arturo , Rosell Cristina M , Pérez‐Munuera Isabel , Hernando Isabel
Published: March 2007

The disrupted gluten structure of infested wheat flours leads to low‐quality doughs unusable in bread‐making processes. Enzymes are replacing chemical treatments in the food industry as a tool to treat weak flours. Glucose oxidase is one of the most promising oxidative enzymes, although its efficiency compared with the alcohol‐soluble fraction of gluten proteins has not yet been demonstrated. If this enzyme could restore the broken covalent bonds between glutenin subunits, the gluten network of damaged wheat flour would recover its native structure and functionality. This treatment would allow bakers to use damaged flour, reducing the economic losses caused by this plague around Europe and North Africa. Electrophoretic studies demonstrated the formation of high‐molecular‐weight aggregates in the glutenin fraction, which had a characteristic thermal stability depending on enzyme dosage. Those molecular studies agreed with the bread‐making assays made with maximum enzyme dosage and microstructure determination. Overall results showed that glucose oxidase is a real alternative to traditionally used chemical oxidants. It acted specifically on the high‐molecular‐weight glutenin subunits of damaged wheat, forming dityrosine crosslinks between the wheat proteins, which reinforced the gluten network and gave away the dough functionality. Copyright © 2007 Society of Chemical Industry
Lipolysis in red clover with different polyphenol oxidase activities in the presence and absence of rumen fluid
Authors: Lee Michael RF , Parfitt Lorna J , Scollan Nigel D , Minchin Frank R
Published: March 2007

This experiment aims to determine whether polyphenol oxidase (PPO) can reduce the extent of lipolysis and the consequent polyunsaturated fatty acid loss through microbial biohydrogenation in red clover when incubated in the presence of rumen fluid. PPO is involved in the browning reaction of red clover leaves when cut or crushed and exposed to air. It starts the browning process by oxidizing endogenous phenols to quinones, which contain electrophilic sites. These sites react with nucleophilic sites of other compounds such as proteins and have been shown to reduce proteolysis and lipolysis in silo. Two lines of red clover (cv. Milvus), a genotypic mutant with reduced PPO activity (L) and the wild type (H) with a high level of PPO activity, were cut 3 cm above soil level, crushed and cut into 1 cm strips before being loaded into incubation bottles. These were then incubated in anaerobic buffer at 39 °C in either the absence (−) or the presence (+) of rumen microorganisms. The incubations were then compared over a 24 h time course in terms of lipolytic activity. Characterization of the tissues showed PPO activities of 25.3 and 5.13 U g−1 fresh weight for H and L, respectively. Lipolysis, measured as the proportional decline in the membrane lipid, was reduced (P < 0.001) with increasing PPO activity in both the presence (+) and absence (−) of rumen microorganisms. However, values were significantly higher (P < 0.001) in the presence of rumen microorganisms, with values after the 24 h incubation of 0.28, 0.42, 0.72 and 0.82 for H−, L−, H+ and L+, respectively. Biohydrogenation of C18:2 and C18:3 polyunsaturated fatty acids were significantly lower in the H+ treatment than the L+ treatment, with mean values after 24 h incubation of 53% and 57% (P < 0.05) for C18:2 and 65% and 74% (P < 0.01) for C18:3, respectively. Changes that occurred in the lipid fractions (membrane lipid, diacylglycerol, triacylglycerol and free fatty acids) during the incubations are also reported and discussed. These results support the selection of forages high in PPO activity to reduce polyunsaturated fatty acid loses in the rumen. Copyright © 2007 Society of Chemical Industry
Evaluation of markers for the traceability of potato tubers grown in an organic versus conventional regime
Authors: Camin Federica , Moschella Anna , Miselli Francesca , Parisi Bruno , Versini Giuseppe , Ranalli Paolo , Bagnaresi Paolo
Published: March 2007

Identification of parameters discriminating organic and conventional produce should help prevent misconduct and could provide a firm basis for comparative assessment of the two types of produce. In this report, we compare for selected markers organically versus conventionally grown tubers in four separate field trials. Within each field trial, organic and conventional tubers were subjected to the same pedoclimatic conditions as they were grown in adjacent plots. In all sites and in both cultivars tested, irrespective of environment, organic tubers exhibited a significant enrichment in 15N‰ when compared to their conventional counterparts. Also, the sum of all samples from the four sites (organic versus conventional) showed higher δ15N‰ (7.17 ± 48% versus 3.36 ± 38%; means ± CV%; n = 39; P < 0.001); furthermore, setting as threshold value for assignment in the organic group the lowest δ15N observed for organic samples (i.e. + 4.3‰), only 15% of conventional tubers were misclassified. On the other hand, further parameters selected on the basis of reports of alterations as a consequence of agricultural technique—ascorbic acid, protein content and dry matter—did not show consistent trends of variation throughout the four field trials. We conclude that, as opposed to other relevant parameters, 15N enrichment appears as a promising discriminative marker. Copyright © 2007 Society of Chemical Industry
Effect of modified atmosphere and vacuum packaging on microbial, chemical and sensory quality indicators of fresh, filleted Sardina pilchardus at 3 °C
Authors: Stamatis Nikolaos , Arkoudelos John S
Published: March 2007

The self‐life, quality and safety of refrigerated sardine fillets (Sardina pilchardus) were determined at 3 °C in atmospheric air, vacuum and modified atmosphere (50% CO2/50% N2) packaging conditions. Microbiological, physico‐chemical and sensory parameters were utilised as quality indicators. The microbial flora of sardine comprised—according to order of occurrence—Shewanella putrefaciens, pseudomonads, Brochothrix thermosphacta, lactic acid bacteria and, finally, Enterobacteriaceae. Bacteria grew most quickly in sardines stored in air, followed by those in vacuum packaging, and the lowest counts were found in modified atmosphere packaging. The concentrations of moisture, ash, protein, fat and polyunsaturated fatty acids were not affected during the storage period compared to the pH values and the concentrations of lactate and ammonia that showed significant differences. Copyright © 2007 Society of Chemical Industry
Determination of alkaloids and phenolic compounds in black tea processed by two different methods in different plucking seasons
Authors: Turkmen Nihal , Velioglu Y Sedat
Published: March 2007

The effects of two different rolling methods and three tea plucking seasons on alkaloids and phenolics, mainly flavan‐3‐ols and theaflavins, in black tea were studied using an improved high‐performance liquid chromatographic method. Better separation of all tea compounds analyzed—the most important factor for their identification and quantitation—was achieved only with long elution gradients, which overcame the limitations of previously reported methods. Precision of the assay method was very high since intra‐day and inter‐day variations were within 0.76% and 1.66%, respectively. All analytes exhibited good linearity over the range evaluated with a correlation coefficient of 0.9987–1.000. Among the four solvents evaluated, 80% methanol was the most solvent for extracting individual tea compounds. The extraction method applied exhibited good repeatability (CV: 0.39–3.29%). The content of tea compounds analyzed varied with processing method and plucking season. Teas processed using the Cay‐Kur method contained higher levels of identified phenolic compounds than orthodox teas, but their alkaloid content was similar to each other. The most abundant alkaloid in teas was caffeine, ranging from 17.84 mg g−1 dry weight in September plucking to 23.79 mg g−1 dry weight in May plucking. With respect to phenolic compounds, theaflavins were at the highest level, 14.27 mg g−1 dry weight, in Cay‐Kur tea processed in May. Copyright © 2007 Society of Chemical Industry
High performance liquid chromatography‐mass spectrometry analysis of protoberberine alkaloids in medicine herbs
Authors: Ren Lingling , Xue Xingya , Zhang Feifang , Xu Qing , Liang Xinmiao
Published: March 2007

RP‐HPLC is the main method for the analysis of alkaloids. However, peak tailing is a problem that commonly occurs in the separation of alkaloids. In order to overcome this, three kinds of RP columns were compared for the analysis of protoberberine alkaloids in Coptidis Rhizoma and Phellodendri Cortex in this work. XTerra MS C18 column was the best one which gave the best symmetry factor under the same conditions. With this column, a good separation of the crude extracts of C. Rhizoma and P. Cortex was achieved using 0.1% v/v formic acid buffer and methanol as mobile phase. At the same time, the crude extracts of C. Rhizoma and P. Cortex were analyzed by the LC‐ESI‐MSn and LC‐atmospheric pressure chemical ionization (APCI)‐MSn methods. In the analysis of HPLC‐ESI/MSn, structures of five protoberberine alkaloids were elucidated, compared to authentic standards, and data from the literature. At the same time, the structure of a novel compound was elucidated. In the HPLC‐APCI/MSn analysis, there was an interesting phenomenon that the relative abundance of the ions M+ and [M + 2]+ was different for different alkaloids. The possible fragmentation pathways of protoberberine alkaloids in APCI/MS analysis were studied for the first time in the present work.
Identification and determination of triterpenoids in Hieracium pilosella L.
Authors: Gawrońska‐Grzywacz Monika , Krzaczek Tadeusz
Published: March 2007

Fractions of triterpenoids have been isolated from herb, inflorescences, and rhizomes with roots of Hieracium pilosella by typical extraction with petroleum ether. The fraction from inflorescences was investigated using GC‐MS techniques. The occurrence of α‐ and β‐amyrin, taraxerol, taraxasterol, and fern‐7en‐3β‐ol has been observed. Quantitative analysis was also performed and taraxasterol is distinctly predominant in this triterpenoid fraction. Thin‐layer chromatography on silica gel was performed on all the investigated fractions and additionally revealed the occurrence of lupeol and ψ‐taraxasterol in vestigial quantities. All of the triterpenoid components are reported for the first time in the investigated plant.
Study of the complexation of different methacrylates with cyclodextrins employing a combination of electrophoretic, chromatographic, and NMR‐spectroscopic methods
Authors: Al‐Rimawi Fuad , Pyell Ute
Published: March 2007

The present study describes the application of capillary electromigration techniques; CEC and micellar EKC (MEKC), and the application of spectroscopic methods; 1H NMR and 1H NOESY spectroscopy to investigate interactions between CDs (α‐CD, statistically methylated β‐CD, hydroxypropyl‐β‐CD, and 2‐hydroxypropyl‐γ‐CD) and different methacrylates (adamantyl, isobornyl, cyclohexyl, and phenyl methacrylate). It is shown that these methods complement each other. While CD‐mediated MEKC is a rapid screening technique for comparing complex stabilities in aqueous media, 1H NMR chemical shift analysis provides quantitative data for very strong methacrylate‐CD complexes and CD‐mediated CEC provides quantitative data for complexes with lower complex forming constants. CD‐mediated MEKC did not prove to be suitable for the calculation of complex forming constants. Reasons are discussed. 1H NOESY spectra were used to study spatial relationships between host and guest atoms.
Reduction of chloride matrix effect using silver oxide as a precipitating reagent for the determination of trace anions in chloride‐rich samples via ion chromatography
Authors: Houtun Fu , Chuncheng Huang John , Limin Zhao , Fang Chen
Published: March 2007

A new method was developed for the determination of trace anions in chloride‐rich samples via ion chromatography by reducing the concentration of chloride ions using silver oxide as a precipitating reagent. In this method the sample pretreatment was started with the addition of silver oxide powder followed by 8 min of stirring and 2 min of centrifugation at a speed of 1500 rpm. The supernatant was diluted with a 1:10 ratio using deionized water and filtered with a 0.22 μm NC filter. All the samples were analyzed in a Dionex ICS‐2500 system with an ED50 electrochemical detector in conductivity mode. On the basis of Dionex IonPac AG18 (50 mm×2 mm) and AS18 (250 mm×2 mm) columns, 25 μL sample filtrate was eluted isocratically with a mobile phase of 32 mmol/L NaOH at a flow rate of 0.25 mL/min and each eluted analyte was detected after postcolumn suppression via a Dionex anion suppressor ULTRA II (2 mm). With this method most of the common anions at mg/kg level in chloride‐rich samples can be accurately quantified. By controlling the equivalent weight ratio of silver oxide to chloride in sample solutions and the time of pretreatment, the free silver and chloride ions in the sample solution are optimized such that most coexisting common anions can be determined simultaneously.
Chemical characteristics of three medicinal plants of the Panax genus determined by HPLC‐ELSD
Authors: Wan Jian‐Bo , Li Shao‐ping , Chen Jun‐Ming , Wang Yi‐Tao
Published: March 2007

The morphological appearance and main ingredients of three Chinese medicines (CMs), P. ginseng, P. quinquefolius, and P. notoginseng of the Panax genus, are similar. However, their pharmacological activities are obviously different. To ensure their safety and efficacy, chemical characteristics of the three CMs were determined using pressurized liquid extraction and HPLC‐evaporative light scattering detection. Twelve major saponins, namely notoginsenoside R1, pseudo‐ginsenoside F11, ginsenosides Rg1, Re, Rf, Rb1, Rg2, Rc, Rb2, Rb3, Rd, and Rg3 were also quantitatively compared among the three CMs. The contents of total investigated saponins varied considerably, by up to 4–14‐fold, between the highest (P. notoginseng, 82.8–136.5 mg/g) and the lowest values (P. ginseng, 10.0–21.1 mg/g). Hierarchical clustering analysis based on the characteristics of 11 investigated saponins (except ginsenoside Rb3) and notoginsenoside R1, pseudo‐ginsenoside F11, and the ratio of ginsenoside Rg1/Rb1 and Rg1/Re showed that 56 tested samples were divided into three main clusters in accordance with the three Panax species. Similarity evaluation of chromatograms was also performed using “Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine (Version 2004 A)”. The results showed that a high degree of similarity existed within individual clusters, but a low degree between the clusters, which could be used for quality control of the three CMs.
Development of a validated HPLC method for the determination of four 1,4‐benzodiazepines in human biological fluids
Authors: Samanidou Victoria F. , Pechlivanidou Anastasia P. , Papadoyannis Ioannis N.
Published: March 2007

A simple and sensitive HPLC method was developed and validated for the determination of four frequently prescribed 1,4‐benzodiazepines: alprazolam (ALP), bromazepam (BRZ), diazepam (DZP), and flunitrazepam (FNZ). Separation was achieved on an Inertsil C8 analytical (250 mm×4 mm, 5 μm) column, after selective extraction of benzodiazepine drugs from biological matrices by means of SPE. Isocratic elution was performed with a mobile phase consisting of CH3COONH4, 0.05 M CH3OH, and CH3CN (33:57:10 by volume). Quantification was performed at 240 nm with mefenamic acid (6 ng/μL) as the internal standard. DSC‐18 Supelco cartridges provided high absolute recoveries (81–115%). The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability, and sensitivity. Repeatability (n = 8) and between‐day precision (n = 8) revealed RSD <12%. Recoveries from biological samples ranged from 81.2 to 115%. The detection limit of the method was calculated as 3.3–10.2 ng in blood plasma and 2.6–12.6 ng in urine for 20 μL injection volume. The method was applied to spiked biological matrices. Moreover, the method was applied to real samples of urine after an oral administration.
Simultaneous determination of four tanshinones in salvia miltiorrhiza by pressurized liquid extraction and capillary electrochromatography
Authors: Li Peng , Li Shao‐Ping , Yang Feng‐Qing , Wang Yi‐Tao
Published: March 2007

A pressurized liquid extraction (PLE) and CEC were developed for the simultaneous determination of four tanshinones (dihydrotanshinone I, cryptotanshinone, tanshinone I, and tanshinone IIA) in Salvia miltiorrhiza. High extraction efficiency (> 98.5%) was achieved under the optimum PLE conditions. A good separation was obtained by using a Hypersil C18 capillary (3 μm, 100 μm/25 cm) with a mixture of 30 mM Tris‐HCl (pH 8.5)‐ACN (1:3, v/v) as BGE solution running at 20 kV and 20°C within 12 min. All the calibration curves showed good linearity (r2 >0.9958) within test ranges. The developed method showed good repeatability for the quantification of four investigated components in S. miltiorrhiza with intra‐ and interday variations of less than 4.4 and 6.8%, respectively. The validated method was successfully applied to quantify four tanshinones in S. miltiorrhiza, which is helpful to control the quality of S. miltiorrhiza.
Combination of COFRADIC and high temperature – extended column length conventional liquid chromatography: A very efficient way to tackle complex protein samples, such as serum
Authors: Sandra Koen , Verleysen Katleen , Labeur Christine , Vanneste Lies , D'Hondt Filip , Thomas Grégoire , Kas Koen , Gevaert Kris , Vandekerckhove Joël , Sandra Pat
Published: March 2007

The previously reported COmbined FRActional DIagonal Chromatography (COFRADIC) methodology, in which a subset of peptides representative for their parent proteins are sorted, is particularly powerful for whole proteome analysis. This peptide‐centric technology is built around diagonal chromatography, where peptide separations are crucial. This paper presents high efficiency peptide separations, in which four 250×2.1 mm, 5 μm Zorbax 300SB‐C18 columns (total length 1 m) were coupled at operating temperatures of 60°C using a dedicated LC oven and conventional LC equipment. The high efficiency separations were combined with the COFRADIC procedure. This extremely powerful combination resulted, for the analysis of serum, in an increase in the uniquely identified peptide sequences by a factor of 2.6, compared to the COFRADIC procedure on a 25 cm column. This is a reflection of the increased peak capacity obtained on the 1 m column, which was calculated to be a factor 2.7 higher than on the 25 cm column. Besides more efficient sorting, less ion suppression was noticed.
Capillary electrophoresis and microchip capillary electrophoresis with electrochemical and electrochemiluminescence detection
Authors: Du Yan , Wang Erkang
Published: March 2007

Recent advances and key strategies in capillary electrophoresis and microchip CE with electrochemical detection (ECD) and electrochemiluminescence (ECL) detection are reviewed. This article consists of four main parts: CE–ECD; microchip CE–ECD; CE–ECL; and microchip CE–ECL. It is expected that ECD and ECL will become powerful tools for CE microchip systems and will lead to the creation of truly disposable devices. The focus is on papers published in the last two years (from 2005 to 2006).
Multiphoton excitation fluorescence: A versatile detection method for capillary electrophoresis
Authors: Du Wei , Chen Sheng , Xu Youzhi , Chen Zhe , Luo Qingming , Liu Bi‐Feng
Published: March 2007

Multiphoton excitation is a relatively old concept in quantum optics. But using multiphoton excitation fluorescence (MPEF) for bioanalysis is still in its infancy. Recently, MPEF has been introduced into the microseparation field, particularly CE, as a novel detection method. In this paper, MPEF detection for CE is reviewed, including MPEF fundamentals, approaches to achieving MPEF, detector configurations and applications in biological and environmental analyses. Emphasis will be placed on some recent advances of CE‐MPEF in our laboratory. Challenges and future prospects are also discussed.