bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of bacteriocins from two Lactococcus lactis subsp. lactis isolates
Authors: Akçelik Oya , Tükel Çaǧla , Özcengiz Gülay , Akçelik Mustafa 
Published: March 2006

AbstractIn this study, bacteriocins from two Lactococcus lactis subsp. lactis isolates from raw milk samples in Turkey designated OC1 and OC2, respectively, were characterized and identified. The activity spectra of the bacteriocins were determined by using different indicator bacteria including Listeria, Bacillus and Staphylococcus spp. Bacteriocins were tested for their sensitivity to different enzymes, heat treatments and pH values. Loss of bacteriocin activities after α‐amylase treatment suggested that they form aggregates with carbohydrates. Molecular masses of the purified bacteriocins were determined by SDS‐PAGE. PCR amplification was carried out with specific primers for the detection of their structural genes. As a result of these studies, the two bacteriocins were characterized as nisin and lacticin 481, respectively. Examination of plasmid contents of the isolates and the results of plasmid curing and conjugation experiments showed that in L. lactis subsp. lactis OC1 strain the 39.7‐kb plasmid is responsible for nisin production, lactose fermentation and proteolytic activity, whereas the 16.0‐kb plasmid is responsible for lacticin 481 production and lactose fermentation in L. lactis subsp. lactis OC2 strain.
Expanded bed adsorption as a fast technique for the large‐scale purification of the complete isoform pool of Ber e 1, the major allergen from Brazil nuts
Authors: van Boxtel Evelien L. , van Koningsveld Gerrit A. , Koppelman Stef J. , van den Broek Lambertus A. M. , Voragen Alfons G. J. , Gruppen Harry 
Published: March 2006

AbstractA new, fast, large‐scale purification method for Ber e 1, the major allergen from Brazil nuts, using expanded bed adsorption (EBA) chromatography, is presented. Using EBA, crude extracts can be applied to a fluidized column, which allows the unhindered passage of particulate impurities, thereby avoiding time‐consuming centrifugation or filtration steps. With this new purification method, 2.8 g of Ber e 1 was obtained from 85 g defatted Brazil nut meal, essentially within 1 day. Various structural as well as immunochemical characteristics of the purified protein were determined, and compared to those of Ber e 1 purified using conventional chromatographic techniques. The complete pool of Ber e 1 isoforms was collected using EBA. The most abundant isoforms were observed to have pI around 8 and heterogeneity was observed in both the large and the small subunit of the heterodimeric protein. Ber e 1 has a highly ordered secondary structure. No apparent differences in immune reactivity were observed between EBA purified Ber e 1 and conventionally purified Ber e 1, using IgE‐binding experiments. Thus, using EBA, Ber e 1 can be purified fast and on gram‐scale, while having purity equal to that of conventionally purified Ber e 1.
Identification of nobiletin metabolites in mouse urine
Authors: Li Shiming , Wang Zhenyu , Sang Shengmin , Huang Mou‐Tuan , Ho Chi‐Tang 
Published: March 2006

AbstractNobiletin, a major component of citrus polymethoxyflavones, has many potential significant health benefits. While the biological activities of nobiletin have been widely reported, its in vitro and in vivo metabolic fate has been rarely studied. To explore the biotransformation mechanism of nobiletin we conducted an investigation into its metabolic profile in mouse urine, by various analytical techniques. Due to sample amount limitations for isolating and characterizing an individual metabolite, two possible nobiletin metabolites were prepared in a similar multi‐step organic synthetic route: 3′‐hydroxy‐5,6,7,8,4′‐pentamethoxyflavone (3′‐demethylnobiletin) and 4′‐hydroxy‐5,6,7,8,3′‐pentamethoxyflavone (4′‐demethylnobiletin). Normal phase (silica gel) and C18 reverse phase chromatography, as well as liquid chromatography‐mass spectrometry‐mass spectrometry, were employed in the separation of 3′‐demethylnobiletin and 4′‐demethylnobiletin, however, without success due to the structural similarities of these mono‐demethylated nobiletins. Using a chiral packed column eluted under supercritical fluid chromatography (SFC) conditions, a clear separation was achieved. Thus, by comparing the SFC profiles of metabolite mixtures with the synthesized standard compounds, the major nobiletin metabolite of mouse urine is identified as 4′‐demethylnobiletin, whereas 3′‐demethylnobiletin is a minor metabolite. In this study, the concentration of 4′‐demethylnobiletin in mouse urine is 28.9 μg/mL.
Survey of the occurrence of Aflatoxin M1 in ovine milk by HPLC and its confirmation by MS
Authors: Bognanno Matteo , La Fauci Luca , Ritieni Alberto , Tafuri Alessio , De Lorenzo Antonino , Micari Pietro , Di Renzo Laura , Ciappellano Salvatore , Sarullo Virginia , Galvano Fabio 
Published: March 2006

AbstractDuring the period of October–July 2000, 240 samples of dairy ewes milk, obtained from farms of Enna (Sicily, Italy), were checked for Aflatoxin M1 (AFM1) by HPLC using a fluorimetric detector. The limit of detection and the limit of quantification were 250 ng/L for AFM1. All the positive milk samples for AFM1 were confirmed by LC‐MS. AFM1 was detected in 81% of milk samples, ranging from 2 to 108 ng/L. Three samples were over the legal limits (50 ng/L). Mean contamination of samples obtained from stabulated ewes was higher than that from grazing ewes (35.27 vs. 12.47 ng/L). Furthermore, samples collected in the period September–October showed higher contamination than samples collected during the other months (42.68 vs. 10.55 ng/L). Both differences are related to the administration of compound feed. Based on current toxicological knowledge we concluded that the AFM1 contamination levels recorded in ewe milk did not present a serious human health hazard. However, as ewe milk is exclusively used to produce cheese due to its higher protein content, and also considering the preferential binding of AFM1 to casein during coagulation of milk, a potentially high concentration effect could occur, thus the surveillance of contamination levels should be more continuous and widespread.
New Monascus metabolites: Structure elucidation and toxicological properties studied with immortalized human kidney epithelial cells
Authors: Knecht Anja , Cramer Benedict , Humpf Hans‐Ulrich 
Published: March 2006

AbstractMonascus sp. are used for the production of red yeast rice, which has been applied in Asian food and medicine for centuries. The fungi form several secondary metabolites, among others the monascopyridines A and B. We have now detected two new monascopyridines (named C and D) with similar UV absorption spectra and maxima at 306–307 nm in red rice fermented with M. purpureus. The new monascopyridines have the same chromophores as the already known and differ in a missing γ‐lactone ring only. Monascopyridine C has a hexanoyl side chain, whereas monascopyridine D is the higher homologue with an octanoyl side chain. The toxicological properties of monascopyridines were studied using immortalized human kidney epithelial cells, displaying cytotoxic effects in micromolar concentrations with median effective concentration values between 20.7 and 43.2 μmol/L, depending on the compound and method used. The monascopyridines C and D did not induce apoptosis. However, they caused a rise of the mitotic index from 3.21 ± 0.27% (control) to maximum 8.14 ± 0.89% (monascopyridine D) by an accumulation of cells in the metaphase with a simultaneous decrease of cells in the ana‐ and telophase. Monascopyridine‐induced metaphase arrest is caused by a partial or complete loss of the spindle apparatus as indicated by the occurrence of abnormal metaphases and immunological staining of α‐tubulin. These effects are indicating an aneuploidic potential and therefore the monascopyridines C and D might contribute to tumor formations.
Stable isotope dilution analysis of the Fusarium mycotoxins deoxynivalenol and 3‐acetyldeoxynivalenol
Authors: Bretz Michael , Beyer Marita , Cramer Benedikt , Humpf Hans‐Ulrich 
Published: March 2006

AbstractTrichothecenes are secondary metabolites produced by several fungi of the Fusarium genus during their growth period. They inhibit protein biosynthesis in eukaryotic cells resulting in numerous toxic effects such as diarrhea, vomiting, and gastro‐intestinal inflammation. Considering its occurrence in food and feedstuff, deoxynivalenol (DON) is one of the most important trichothecenes. We report the synthesis of stable isotope labeled 15‐d1‐deoxynivalenol (15‐d1‐DON) from its natural precursor 3‐acetyldeoxynivalenol (3‐AcDON) as starting material. Furthermore, a method for the analysis of DON and 3‐AcDON using HPLC‐MS/MS with stable isotope labeled 15‐d1‐DON and 3‐d3‐AcDON as internal standards has been developed. In total, 18 cereal product samples were analyzed with contamination levels ranging from 10–301 μg/kg for DON and 5–14 μg/kg for 3‐AcDON. This is the first report of an isotope dilution MS method for the analysis of type B‐trichothecenes.
A new solid phase extraction clean‐up method for the determination of 12 type A and B trichothecenes in cereals and cereal‐based food by LC‐MS/MS
Authors: Klötzel Marianna , Lauber Uwe , Humpf Hans‐Ulrich 
Published: March 2006

AbstractA new reliable and cost‐efficient solid phase extraction‐based clean‐up method for the determination of 12 type A and B trichothecenes [deoxynivalenol (DON), nivalenol, 3‐acetyldeoxynivalenol, 15‐acetyldeoxynivalenol, fusarenon‐X, T‐2 toxin, HT‐2 toxin, neosolaniol, monoacetoxy‐scirpenol, diacetoxyscirpenol, T‐2 triol and T‐2 tetraol] in cereals and cereal‐based food is presented. Furthermore, the suitability for the simultaneous determination of zearalenone is examined. Toxins were extracted from cereal samples using ACN/water (80/20, v/v), purified by means of a new Bond Elut Mycotoxin® column and analyzed via liquid chromatography‐electrospray ionization tandem mass spectrometry. Limits of detection were calculated for the matrix wheat and ranged from 0.3 to 5 ng/g, depending on the toxin. Average recovery rates for the tested compounds in seven cereal‐based matrices have been determined ranging from 65 to 104%. The relative standard deviations of the complete method ranged from 2.67 (DON, wheat) to 20.0% (T‐2 toxin, oats).
The L513S polymorphism in medium‐chain acyl‐CoA synthetase 2 (MACS2) is associated with risk factors of the metabolic syndrome in a Caucasian study population
Authors: Lindner Inka , Rubin Diana , Helwig Ulf , Nitz Inke , Hampe Jochen , Schreiber Stefan , Schrezenmeir Jürgen , Döring Frank 
Published: March 2006

AbstractEnzymes of the medium‐chain acyl‐CoA synthetase (MACS) family catalyze the ligation of medium chain fatty acids with CoA to produce medium‐chain‐acyl‐CoA. At least four members of the MACS gene family are clustered on human chromosome 16p12. Association studies in the Japanese Suita cohort of MACS polymorphisms and various phenotypes revealed the contribution of the Leu513Ser polymorphism in MACS2 to multiple risk factors of the metabolic syndrome. Here, we investigated the association between this polymorphism and different risk factors in the Caucasian Metabolic Intervention Cohort Kiel. Seven hundred and sixteen male subjects aged 45–65 years were recruited for a standard oral glucose tolerance test and the postprandial assessment of metabolic parameters after an oral metabolic tolerance test (oMTT; 1017 kcal, 51.6% fat, 29.6% carbohydrates, 11.9% protein). The MACS2 Leu513Ser polymorphism was determined by TaqMan‐Assay in 705 subjects. Postprandial triglyceride levels following oMTT [area under the curve (AUC)] were significantly higher in subjects carrying the Ser allele compared to subjects homozygous for the Leu allele (1690 ± 100 mg×h/dL ersus 1514 ± 39 mg×h/dL, p = 0.04). Significant differences between genotype groups were also found for fasting (108 ± 1.9 mg/dL versus 104 ± 0.66 mg/dL, p = 0.04) and postprandial (AUC 535 ± 11 versus 512 ± 4.0, p = 0.02) glucose levels as well as for high‐density‐lipoprotein, body mass index, waist circumference, systolic and diastolic blood pressure. Carriers of the Ser allele also show an increased risk of impaired glucose metabolism (OR: 1.48, 95% confidence interval: 0.98–2.27, p = 0.07), adiposity (1.8, 1.16–2.81, p = 0.01) and hypertension (1.5, 0.99–2.17, p = 0.06). In conclusion, our results suggest an involvement of the MACS2 Leu513Ser polymorphism in the development of the metabolic syndrome in Caucasian population. Additionally, the higher triglyceride and glucose levels after an oMTT support a possible functional impact of the polymorphism in vivo.
1H and 13C NMR spectral assignments of four dammarane triterpenoids from carnauba wax
Authors: de Brito Cysne Juliana , Braz‐Filho Raimundo , Assunção Marcus Vinícius , de Andrade Uchoa Daniel E. , Silveira Edilberto R. , Pessoa Otília Deusdênia L. 
Published: March 2006

AbstractThe phytochemical investigation of carnauba wax led to the isolation of three new dammarane triterpenoids 1, 2 and 4, together with the known triterpene 3. The structures of the new compounds were determined by 1D and 2D NMR spectroscopy and by comparison with published data for closely related compounds. Copyright © 2006 John Wiley & Sons, Ltd.
Determinants of epidermal nerve fiber density in normal individuals
Authors: Umapathi T. , Tan Wan Loo , Tan Nigel C. K. , Chan Yiong Huak 
Published: March 2006

AbstractWe studied the relationship between epidermal innervation and age, gender, height, and weight. Intraepidermal nerve fiber density (IENFD) of skin biopsies obtained from the proximal thigh and ankle of 84 normal individuals was quantified. A linear regression model was performed using IENFD at the thigh, IENFD at the ankle, and the thigh IENFD/ankle IENFD ratio, with age, gender, and height–weight interaction as predictors. An independent, negative correlation was found between age and IENFD at the ankle. No correlation was found between age and IENFD at the thigh. With increasing age the thigh IENFD/ankle IENFD ratio, a measure of the length‐dependent distal‐to‐proximal gradient of epidermal nerve density, increased significantly. Gender, height, and body weight did not independently influence IENFD at either site. In normal individuals, distal epidermal innervation decreases in a length‐dependent manner with advancing age. This must be considered when interpreting IENFD in disease states. Muscle Nerve, 2006
Influence of time of day on tendon compliance and estimations of voluntary activation levels
Authors: Pearson Stephen J. , Onambele Gladys N. L. 
Published: March 2006

AbstractWe investigated the importance of tendon stiffness on estimations of central activation capacity (CAC). Patella tendon–force elongation relationship, quadriceps torque, and response to 50‐μs, 100‐HZ electrical twitch doublets were studied at ∼8:00 A.M. and ∼6:00 P.M. in 8 healthy young men. Results show that in the evening, as compared with the morning, tendon stiffness decreased by 20.2 ± 9.5% (P = 0.03) and time to twitch peak (Ttp) increased by 55% (P = 0.04). Tendon stiffness and Ttp correlated significantly (r = 0.28, P < 0.05). Whereas the CAC, calculated as the ratio of force preceding the interpolated twitch (IT) to the total force at the peak of the IT, showed no change with time of day, calculations that used twitch ratios suggested CAC decrements (−10.3%, P = 0.03, unpotentiated; −10%, P = 0.02, potentiated ratio) in the evening. This study shows that CAC estimations are invalid when tendon properties are not taken into account, an error that would have important implications in a clinical setting. Muscle Nerve, 2006
Maximizing project cash availability
Authors: Szmerekovsky Joseph G. , Vairaktarakis George L. 
Published: March 2006

AbstractConsider a project during the life cycle of which there are cash payouts and in‐flows. To better meet his financial commitments, the project owner would like to meet all deadlines without running out of cash. We show that the cash availability objective is similar to the total weighted flowtime used to measure work‐in‐progress performance in the scheduling and inventory control literatures. In this article we provide several specialized solution methods for the problem of minimizing total weighted flowtime in an arbitrary acyclic project network, subject to activity release times and due dates, where the activity weights may be positive or negative and represent cash in‐ and out‐flows. We describe the structure of an optimal solution and provide several efficient algorithms and their complexity based on mincost and maxflow formulations. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006
Interference temperature: a metric for dynamic spectrum utilization
Authors: Kolodzy Paul J. 
Published: March 2006

AbstractInterference temperature has been proposed by the FCC as a metric for interference analysis. The purpose of the metric is to demystify and remove the subjective context that has been the basis of interference analysis within the regulatory agencies. The development of an interference metric is critical if more intensive, dynamic use of the spectrum is desired. There has been very little specified as to the origins, use, and challenges of an interference metric. This paper provides an introductory analysis of the interference temperature metric. Copyright © 2006 John Wiley & Sons, Ltd.
Outage performance of a hybrid DS/FH spread‐spectrum signal in an ISM band
Authors: Li Hanyu , Syed Mubashir , Yao Yu‐Dong 
Published: March 2006

AbstractThis paper develops an analytical model for characterizing the coexistence interference in the unlicensed industrial, scientific and medical (ISM) bands, based on radio frequency measurement results in the 2.4 GHz ISM band. The modeling approach presented here offers a simple methodology for profiling the interference from devices occupying a common spectrum. Outage performance using the interference model is exemplified through the analysis for a hybrid direct‐sequence frequency‐hopping spread‐spectrum signal. The work presented in this paper looks to provide insight by means of quantitative evaluation of signal outage in a coexistence environment that can be used for engineering design of applications for unlicensed bands as well as function as a tool in the development process for future spectrum management policy models. Copyright © 2006 John Wiley & Sons, Ltd.
Opportunities and challenges in software radio design for interference management
Authors: Bose Vanu 
Published: March 2006

AbstractInterference management is a critical aspect of the design and deployment of any wireless network. Interference can reduce quality, deny service or significantly reduce the efficiency of spectrum use. Software radio holds the potential to increase the pace of innovation, flexibility and spectrum efficiency of wireless communications. Interference management is a critical aspect for devices and system design for any wireless system, and involves unique performance flexibility trade‐offs for software radio design. This paper provides a review of interference management techniques by looking at two representative communications systems: cellular networks and unlicensed wireless local area networks. These two systems are chosen since they are representative of two very different types of communications networks. Cellular systems typically operate in a licensed band and have separate frequencies for transmission and reception, while 802.11b operates in an unlicensed spectrum and utilizes the same band for transmission and reception. The paper starts with a review of the fundamental interference issues and an overview of software radio systems. Following that, for each interference issue, the approaches and constraints for each standard are reviewed and the opportunities and challenges for software radio design are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Detectable minimal residual disease before allogeneic hematopoietic stem cell transplantation predicts extremely poor prognosis in children with acute lymphoblastic leukemia
Authors: Sramkova Lucie , Muzikova Katerina , Fronkova Eva , Krejci Ondrej , Sedlacek Petr , Formankova Renata , Mejstrikova Ester , Stary Jan , Trka Jan 
Published: March 2006

AbstractBackgroundThe level of minimal residual disease (MRD) prior to allogeneic hematopoietic stem cell transplantation (HSCT) has been shown to be an independent prognostic factor for outcome of pediatric patients with high‐risk acute lymphoblastic leukemia (ALL). Retrospective studies which used (semi‐) quantitation of clone‐specific immunoglobulin/T‐cell receptor (Ig/TCR) rearrangements have documented the feasibility and practicality of this technique. This approach has also been disputed due to the occurrence of clonal evolution and generally high MRD levels prior to HSCT.ProcedureIn our prospective study, MRD before and after HSCT was monitored using quantitative real‐time PCR in a cohort of 36 children with ALL consecutively transplanted in our center between VIII/2000 and VII/2004.ResultsIn 25 of 36 patients, MRD level prior HSCT was assessed. Seventeen patients were classified as MRD‐negative and eight were MRD‐positive up to 9 × 10−2. In MRD‐positive subgroup, seven events (six relapses) occurred post‐transplant in striking contrast to only one relapse in MRD‐negative subgroup (event‐free survival (EFS) log‐rank P < 0.0001). MRD proved to be the only significant prognostic factor in a multivariate analysis (P < 0.0001). Adoptive immunotherapy including donor lymphocyte infusions in patients with adverse dynamics of MRD after HSCT had only limited and/or temporary effect. Clonal evolution did not present a problem precluding MRD monitoring in any of patients suffering a post‐transplant relapse.ConclusionsWe show that MRD quantitation using clonal Ig/TCR rearrangements successfully assesses the risk in pediatric ALL patients undergoing allogeneic HSCT. As our ability to treat detectable MRD levels after HSCT is very limited, alternative strategies for MRD‐positive patients prior HSCT are necessary. Pediatr Blood Cancer 2007;48:93–100. © 2006 Wiley‐Liss, Inc.
Morphology and mechanical properties of polymer nanocomposites with a poly(hydroxy ether of bisphenol A) matrix
Authors: Gurmendi Urko , Eguiazabal Jose Ignacio , Nazabal Jon 
Published: March 2006

AbstractThe poly(hydroxy ether of bisphenol A) (phenoxy (Ph)) has been revealed as a polymeric matrix able to intercalate in, and partially exfoliate a commercial organically modified montmorillonite. Dispersion was attributed to chemical interactions between the Ph and the inorganic clay. A significant increase in the modulus of elasticity (33% with 3.8% montmorillonite (MMT) addition) was observed, together with an unusual increase in ductility attributed to surfactant migration, that should allow tailoring of the processing conditions to widen exfoliation. Ph‐based nanocomposites could be used as a nanostructured masterbatch for producing new polymer nanocomposites by mixing the masterbatch with the polymeric matrices that either miscibilize or are compatible with Ph. Copyright © 2006 Society of Chemical Industry