bluuebunny/crossref_metadata_2025 huggingface dataset:
Deglycosylation of ovalbumin prohibits formation of a heat‐stable conformer
Authors: de Groot Jolan , Kosters Hans A. , de Jongh Harmen H.J.
Published: December 2006

To study the influence of the carbohydrate‐moiety of ovalbumin on the formation of the heat‐stable conformer S‐ovalbumin, ovalbumin is deglycosylated with PNGase‐F under native conditions. Although the enzymatic deglycosylation procedure resulted in a complete loss of the ability to bind to Concavalin A column‐material, only in about 50% the proteins lost their complete carbohydrate moiety, as demonstrated by mass spectrometry and size exclusion chromatography. Thermal stability and conformational changes were determined using circular dichroism and differential scanning calorimetry and demonstrated at ambient temperature no conformational changes due to the deglycosylation. Also the denaturation temperature of the processed proteins remained the same (77.4 ± 0.4°C). After heat treatment of the processed protein at 55°C and pH 9.9 for 72 h, the condition that converts native ovalbumin into the heat‐stable conformer (S‐ovalbumin), only the material with the intact carbohydrate moiety forms this heat‐stable conformer. The material that effectively lost its carbohydrate moiety appeared fully denatured and aggregated due to these processing conditions. These results indicate that the PNGase‐F treatment of ovalbumin prohibits the formation and stabilization of the heat‐stable conformer S‐ovalbumin. Since S‐ovalbumin in egg protein samples is known to affect functional properties, this work illustrates a potential route to control the quality of egg protein ingredients. Biotechnol. Bioeng. 2007;97: 735–741. © 2006 Wiley Periodicals, Inc.
Scale‐up of enzymatic production of lactobionic acid using the rotary jet head system
Authors: Hua Ling , Nordkvist Mikkel , Nielsen Per Munk , Villadsen John
Published: December 2006

Enzymatic oxidation of lactose to lactobionic acid (LBA) by a carbohydrate oxidase from Microdochium nivale was studied in a pilot‐scale batch reactor of 600 L working volume using a rotary jet head (RJH) for mixing and mass transfer (Nordkvist et al., 2003, Chem Eng Sci 58:3877–3890). Both lactose and whey permeate were used as substrate, air was used as oxygen source, and catalase was added to eliminate the byproduct hydrogen peroxide. More than 98% conversion to LBA was achieved. Neither enzyme deactivation nor enzyme inhibition was observed under the experimental conditions. The dissolved oxygen tension (DOT) was constant throughout the tank for a given set of operating conditions, indicating that liquid mixing was sufficiently good to avoid oxygen gradients in the tank. However, at a given oxygen tension measured in the tank, the specific rate of reaction found in the RJH system was somewhat higher than previously obtained in a 1 L mechanically stirred tank reactor (Nordkvist et al., 2007, in this issue, pp. 694–707). This can be ascribed to a higher pressure in the recirculation loop which is part of the RJH system. Compared to mechanically stirred systems, high values of the volumetric mass transfer coefficient, kLa, were obtained when lactose was used as substrate, especially at low values of the specific power input and the superficial gas velocity. kLa was lower for experiments with whey permeate than with lactose due to addition of antifoam. The importance of mass transfer and of the saturation concentration of oxygen on the volumetric rate of reaction was demonstrated by simulations. Biotechnol. Bioeng. 2007;97: 842–849. © 2006 Wiley Periodicals, Inc.
Oxidation of lactose to lactobionic acid by a Microdochium nivale carbohydrate oxidase: Kinetics and operational stability
Authors: Nordkvist Mikkel , Nielsen Per Munk , Villadsen John
Published: December 2006

Oxidation of lactose to lactobionic acid by a Microdochium nivale carbohydrate oxidase was studied. The Km‐value for lactose, obtained by a traditional enzymatic assay, was 0.066 mM at pH 6.4 and 38°C. The effect of oxygen on the enzymatic rate of reaction as well as the operational stability of the enzyme was studied by performing reactions at constant pH and temperature in a stirred tank reactor. Catalase was included in all reactions to avoid inhibition and deactivation of the oxidase by hydrogen peroxide. At pH 6.4 and 38°C, Km for oxygen was 0.97 mM, while the catalytical rate constant, kcat, was 94 s−1. Furthermore, we found that the operational stability of the oxidase was dependent on the type of base used for neutralization of the acid produced. Thus, when 2 M NaOH was used for neutralization of a reaction medium containing 50 mM phosphate buffer, significant deactivation of the oxidase was observed. Also, we found that the oxidase was protected against deactivation by base at high lactose concentrations. A simple model is proposed to explain the obtained results. Biotechnol. Bioeng. 2007;97: 694–707. © 2006 Wiley Periodicals, Inc.
Characterization of the localized hydrodynamic shear forces and dissolved oxygen distribution in sparged bioreactors
Authors: Koynov Athanas , Tryggvason Grétar , Khinast Johannes G.
Published: December 2006

Detailed, high‐resolution numerical simulations of the bubbly flows, used for oxygen delivery and mixing in mammalian cell suspensions, have been performed. The hydrodynamics, shear and normal forces, mass transfer and mass transport from and around individual bubbles and bubble clusters were resolved for different operating conditions, that is, Weber, Morton, and Schmidt numbers. Suspended animal (e.g., mammalian, insect) cells are known to be susceptible to damage potentially leading to cell death, caused by hydrodynamic stresses and oxygen deprivation. Better knowledge of the magnitude of the shear forces and the extent of mixing of the dissolved oxygen in sparged bioreactors can have a significant impact on their future design and optimization. Therefore, the computed liquid‐phase velocity fields were used to calculate and compare the local shear in different types of single bubble wakes and in bubble clusters. Oxygen mass transfer and dissolved oxygen transport were resolved to examine oxygen supply to the cells in the different types of flows. Biotechnol. Bioeng. 2007;97: 317–331. © 2006 Wiley Periodicals, Inc.
Effect of siRNA nuclease stability on the in vitro and in vivo kinetics of siRNA‐mediated gene silencing
Authors: Bartlett Derek W. , Davis Mark E.
Published: December 2006

Small interfering RNA (siRNA) molecules achieve sequence‐specific gene silencing through the RNA interference (RNAi) mechanism. Here, live‐cell and live‐animal bioluminescent imaging (BLI) is used to directly compare luciferase knockdown by unmodified and nuclease‐stabilized siRNAs in rapidly (HeLa) and slowly (CCD‐1074Sk) dividing cells to reveal the impact of cell division and siRNA nuclease stability on the kinetics of siRNA‐mediated gene silencing. Luciferase knockdown using unmodified siRNAs lasts approximately 1 week in HeLa cells and up to 1 month in CCD‐1074Sk cells. There is a slight increase in the duration of luciferase knockdown by nuclease‐stabilized siRNAs relative to unmodified siRNAs after cationic lipid transfection, but this difference is not observed after electroporation. In BALB/cJ mice, a fourfold increase in maximum luciferase knockdown is observed after hydrodynamic injection (HDI) of nuclease‐stabilized siRNAs relative to unmodified siRNAs, yet the overall kinetics of the recovery after knockdown are nearly identical. By using a mathematical model of siRNA‐mediated gene silencing, the trends observed in the experimental data can be duplicated by changing model parameters that affect the stability of the siRNAs before they reach the cytosolic compartment. Based on these findings, we hypothesize that the stabilization advantages of nuclease‐stabilized siRNAs originate primarily from effects prior to and during internalization before the siRNAs can interact with the intracellular RNAi machinery. Biotechnol. Bioeng. 2007;97: 909–921. © 2006 Wiley Periodicals, Inc.
Quantitative analysis of EDC‐condensed DNA on vertically aligned carbon nanofiber gene delivery arrays
Authors: Mann David G.J. , McKnight Timothy E. , Melechko Anatoli V. , Simpson Michael L. , Sayler Gary S.
Published: December 2006

Vertically aligned carbon nanofibers (VACNFs) with immobilized DNA have been developed as a novel tool for direct physical introduction and expression of exogenous genes in mammalian cells. Immobilization of DNA base amines to the carboxylic acids on nanofibers can influence the accessibility and transcriptional activity of the DNA template, making it necessary to determine the number of accessible gene copies on nanofiber arrays. Polymerase chain reaction (PCR) and in vitro transcription (IVT) were used to investigate the transcriptional accessibility of DNA tethered to VACNFs by correlating the yields of both IVT and PCR to that of non‐tethered, free DNA. Yields of the promoter region and promoter/gene region of bound DNA plasmid were high. Amplification using primers designed to cover 80% of the plasmid failed to yield any product. These results are consistent with tethered, longer DNA sequences having a higher probability of interfering with the activity of DNA and RNA polymerases. Quantitative PCR (qPCR) was used to quantify the number of accessible gene copies tethered to nanofiber arrays. Copy numbers of promoters and reporter genes were quantified and compared to non‐tethered DNA controls. In subsequent reactions of the same nanofiber arrays, DNA yields decreased dramatically in the non‐tethered control, while the majority of tethered DNA was retained on the arrays. This decrease could be explained by the presence of DNA which is non‐tethered to all samples and released during the assay. This investigation shows the applicability of these methods for monitoring DNA immobilization techniques. Biotechnol. Bioeng. 2007;97: 680–688. © 2006 Wiley Periodicals, Inc.
Protein engineering of Acidovorax facilis 72W nitrilase for bioprocess development
Authors: Wu Shijun , Fogiel Arthur J. , Petrillo Kelly L. , Hann Eugenia C. , Mersinger Lawrence J. , DiCosimo Robert , O'Keefe Daniel P. , Ben‐Bassat Arie , Payne Mark S.
Published: December 2006

Hydroxycarboxylic acid monomers can be used to prepare industrially important polymers. Enzymatic production of such hydroxycarboxylic acids is often preferred to chemical production since the reactions are run at ambient temperature, do not require strongly acidic or basic reaction conditions, and produce the desired product with high selectivity at high conversion. However, native enzymes often do not perform desired reactions with the efficiency required for commercial applications. Protein engineering was used to significantly increase the specific activity of nitrilase from Acidovorax facilis 72W for the conversion of 3‐hydroxyvaleronitrile to 3‐hydroxyvaleric acid. Overexpression of engineered nitrilase enzymes in Escherichia coli, combined with immobilization of whole cells in alginate beads that can be recycled many times has facilitated the development of a commercially viable bioprocess for production of 3‐hydroxyvaleric acid. Biotechnol. Bioeng. 2007;97: 689–693. © 2006 Wiley Periodicals, Inc.
Enhancement of pyruvate production by osmotic‐tolerant mutant of Torulopsis glabrata
Authors: Liu Liming , Xu Qinglong , Li Yin , Shi Zhongpin , Zhu Yang , Du Guocheng , Chen Jian
Published: December 2006

Pyruvate production by Torulopsis glabrata was used as a model to study the mechanism of product inhibition and the strategy for enhancing pyruvate production. It was found that the concentration of cell growth and pyruvate deceased with the increase of NaCl and sorbitol concentrations. To enhance the osmotic stress resistance of the strain, an NaCl‐tolerant mutant RS23 was screened and selected through a pH‐controlled continuous culture with 70 g/L NaCl as the selective criterion. Compared with the parent strain, mutant RS23 could grow well on the medium containing 70 g/L NaCl or 0.6 mol/L sorbitol. Pyruvate concentration by the mutant strain RS23 reached 94.3 g/L at 82 h (yield on glucose 0.635 g/g) in a 7‐l fermentor with 150 g/L glucose as carbon source. Pyruvate concentration and yield of mutant RS23 were 41.1% and 11.1% higher than those of the parent strain, respectively. The strategy for enhancing pyruvate production by increasing osmotic stress resistance may provide an alternative approach to enhance organic acids production with yeast. Biotechnol. Bioeng. 2007;97: 825–832. © 2006 Wiley Periodicals, Inc.
Cell‐free synthesis of proteins that require disulfide bonds using glucose as an energy source
Authors: Knapp Kurtis G. , Goerke Aaron R. , Swartz James R.
Published: December 2006

The primary objective of this work was to create a cell‐free protein synthesis extract that produces proteins requiring disulfide bonds while using glucose as an energy source. We attempted to avoid using iodoacetamide (IAM) to stabilize the required oxidizing thiol redox potential, since previous IAM pretreatments prevented glucose utilization apparently by inactivating glyceraldehyde 3‐phosphate dehydrogenase (G‐3PDH). Instead, the glutathione reductase (Gor)‐mediated disulfide reductase system was disabled by deleting the gor gene from the KC6 cell‐extract source strain. The thioredoxin reductase (TrxB)‐mediated system was disabled by first adding a purification tag to the trxB gene in the chromosome to create strain KGK10 and then by affinity removal of the tagged TrxB. This was expected to result in a cell extract devoid of all disulfide reductase activity, but this was not the case. Although the concentration of IAM required to stabilize oxidized glutathione in the KGK10 extract could be reduced 20‐fold, IAM pretreatment was still required to avoid disulfide reduction. Nonetheless, active urokinase and murine granulocyte macrophage‐colony stimulating factor (mGM‐CSF) were produced in reactions with KGK10 extract either with affinity removal of TrxB or with 50 µM IAM pretreatment. With the less intensive IAM pretreatment, glucose could be used as an energy source in a production system that promotes oxidative protein folding. This new protocol offers an economically feasible cell‐free system for the production of secreted mammalian proteins as human therapeutics or vaccines. Biotechnol. Bioeng. 2007;97: 901–908. © 2006 Wiley Periodicals, Inc.
Short‐term temperature effects on the anaerobic metabolism of glycogen accumulating organisms
Authors: Lopez‐Vazquez Carlos M. , Song Young‐Il , Hooijmans Christine M. , Brdjanovic Damir , Moussa Moustafa S. , Gijzen Huub J. , van Loosdrecht Mark M. C.
Published: December 2006

Proliferation of glycogen accumulating organisms (GAO) has been identified as a potential cause of enhanced biological phosphorus removal (EBPR) failure in wastewater treatment plants (WWTP). GAO compete for substrate with polyphosphate accumulating organisms (PAO) that are the microorganisms responsible for the phosphorus removal process. In the present article, the effects of temperature on the anaerobic metabolism of GAO were studied in a broad temperature range (from 10 to 40°C). Additionally, maximum acetate uptake rate of PAO, between 20 and 40°C, was also evaluated. It was found that GAO had clear advantages over PAO for substrate uptake at temperatures higher than 20°C. Below 20°C, maximum acetate uptake rates of both microorganisms were similar. However, lower maintenance requirements at temperature lower than 30°C give PAO metabolic advantages in the PAO‐GAO competition. Consequently, PAO could be considered to be psychrophilic microorganisms while GAO appear to be mesophilic. These findings contribute to understand the observed stability of the EBPR process in WWTP operated under cold weather conditions. They may also explain the proliferation of GAO in WWTP and thus, EBPR instability, observed in hot climate regions or when treating warm industrial effluents. It is suggested to take into account the observed temperature dependencies of PAO and GAO in order to extend the applicability of current activated sludge models to a wider temperature range. Biotechnol. Bioeng. 2007;97: 483–495. © 2006 Wiley Periodicals, Inc.
Making integration happen: the families first policy experience
Authors: valentine kylie , Fisher Karen , Thomson Cathy
Published: December 2006

This paper explores the implementation experience of a child and family policy with ambitious integration goals. The questions to be addressed here focus on the factors that facilitated integration, those that hindered it, and the meanings in practice of integration at the levels of service delivery, planning, and management. The policy is Families First, implemented in New South Wales, the largest state in Australia, beginning in 1998. Families First is an ambitious state‐wide initiative that aims to improve the health and wellbeing of children aged from birth to eight years, by supporting parents and carers. This is to be achieved by the development of a coordinated network of prevention and early intervention services that identifies children and families who require further assistance and links them to appropriate support early, before problems become entrenched. Based on the process evaluation of Families First's implementation, this paper argues that successful implementation of Families First as an integration policy was characterized by high levels of participation from a range of actors. We found a number of factors facilitated integration: inclusive practice; building relationships; empowerment; and time and resources. These findings also, however, raise larger questions about the application of integration policies in an early childhood context, where these facilitators are known to be in short supply. Copyright © 2006 John Wiley & Sons, Ltd.
Fischer Carbene Complexes: Beautiful Playgrounds To Study Single Electron Transfer (SET) Reactions
Authors: Sierra Miguel A. , Gómez‐Gallego Mar , Martínez‐Álvarez Roberto
Published: December 2006

The knowledge of the reactivity of Fischer carbene complexes in electron transfer processes is still in the early stage of development, but interesting advances are foreseeable in this young branch of metal–carbene chemistry. Although these compounds have a dual reactivity (which makes them good substrates for oxidation and reduction processes), their behavior towards chemical electron transfer (ET) reagents was unknown until very recently. This article covers the progress accomplished in the reactivity of these compounds towards chemical ET reagents (C8K or SmI2), as well as the use of nonconventional sources of electrons, such as electrospray ionization (ESI) to induce ET processes. Special emphasis will be made on the effect of the structure of the starting carbene in the outcome of the reaction and in discussing the different mechanisms proposed.
Diagnosis of foregut and tailgut cysts by endosonographically guided fine‐needle aspiration
Authors: Hall Diane A. , Pu Robert T. , Pang Yijun
Published: December 2006

Foregut, hindgut, and tailgut cysts are uncommon developmental anomalies. Clinical and radiological diagnosis can present many challenges, especially in adult patients or when the lesions are in unique locations. Thus, diagnosis has traditionally been provided upon surgical resection. We describe the diagnoses of a gastric foregut cyst and a retrorectal tailgut cyst by endosonographically guided fine‐needle aspiration in two adults. The common cytologic features of the specimens are ciliated epithelial cells, proteinaceous material with degenerated debris, histiocytes, and benign appearing epithelium of squamous and/or gastrointestinal type that lack cytologic atypia. The identification of ciliated columnar cells is the key finding. Cytologic diagnosis via endosonographically guided fine‐needle aspiration of foregut/hindgut cyst is accurate and less traumatic than surgical biopsies. Diagn. Cytopathol. 2007;35:43–46. © 2006 Wiley‐Liss, Inc.
Diagnostic effects of prolonged storage on fresh effusion samples
Authors: Manosca Frances , Schinstine Malcolm , Fetsch Patricia A. , Sorbara Lynn , Maria Wilder Anna , Brosky Keith , Erickson Dana , Raffeld Mark , Filie Armando C. , Abati Andrea
Published: December 2006

The effects on morphology and diagnostic interpretation of delayed processing of refrigerated effusion samples have not been well documented. The potential for cellular degeneration has led many laboratories to reflexively fix samples rather than submit fresh/refrigerated samples for cytologic examination. We sought to determine if effusion specimens are suitable for morphologic, immunocytochemical, and DNA‐based molecular studies after prolonged periods of refrigerated storage time. Ten fresh effusion specimens were refrigerated at 4°C; aliquots were processed at specific points in time (days 0, 3, 5, 7, 10, 14). Specimens evaluated included four pleural (3 benign, 1 breast adenocarcinoma) and six peritoneal (2 ovarian adenocarcinomas, 1 malignant melanoma, 2 mesotheliomas, 1 atypical mesothelial) effusions. The morphology of the cytologic preparations from the 10 effusions was preserved and interpretable after 14 days of storage at 4°C. The immunocytochemical profile of the samples (AE1/AE3, EMA, calretinin, and LCA) was consistent from day 0 to day 14. Amplifiable DNA was present in all samples tested on day 14. We conclude that cytopathologic interpretation of effusion samples remains reliable with refrigeration at 4°C even if processing is delayed. Diagn. Cytopathol. 2007;35:6–11. © 2006 Wiley‐Liss, Inc.
To switch or not to switch – the opposing roles of TACI in terminal B cell differentiation
Authors: Salzer Ulrich , Jennings Stephanie , Grimbacher Bodo
Published: December 2006

The TNF superfamily ligands BAFF and APRIL and their three receptors BAFFR, BCMA, and TACI comprise a network that is critically involved in the development and function of humoral immunity. Failure of this complex system is associated with autoimmune disease, B lymphocyte tumours, and antibody deficiency. While BAFF:BAFFR interactions control peripheral B cell survival and homeostasis, BCMA function seems limited to the survival of long‐lived bone marrow plasma cells. The functional activity of the third receptor TACI is, however, ambiguous: while TACI–/– mice predominantly develop autoimmunity and lymphoproliferation, TACI deficiency in humans primarily manifests itself as an antibody deficiency syndrome. An article in this issue of the European Journal of Immunology demonstrates a negative regulation via TACI in human B cells by using TACI specific antibodies. B cell proliferation, class switch recombination, and Ig production induced by various stimuli were inhibited via TACI. Within the BAFF/APRIL network, the expression of the receptors and ligands is spatially, as well as temporally, highly regulated at various stages of B cell development and function. Defining the exact contribution of TACI stimulation by specific triggers in vitro enables us to better understand the complex, context‐dependent responses initiated by TACI in vivo.

See accompanying article http://dx.doi.org/10.1002/eji.200636623
Near‐infrared spectroscopy for the determination of lipid oxidation in cereal food products
Authors: Kaddour Abderrahmane Aït , Grand Evane , Barouh Nathalie , Baréa Bruno , Villeneuve Pierre , Cuq Bernard
Published: December 2006

The present study was aimed at determining the ability of near‐infrared (NIR) spectroscopy to in situ describe fat oxidation kinetics in three different cereal‐based products: salted crackers (20% saturated palm oil and lauric oil, sprayed on surface); healthy crackers (10% unsaturated rapeseed oil, homogeneously distributed inside the product matrix); and moist pasteurised Asian noodles (1.5% unsaturated rapeseed oil, sprayed on surface). Products were stored under accelerated oxidation conditions at 40 °C. Lipid oxidation rates were determined from peroxide value (PV) measurements. We observed no significant changes in PV for the dry crackers (3 meq/kg after 60 days), a slight linear increase in PV for the healthy crackers (40 meq/kg after 60 days), and a rapid increase for the Asian noodles (80 meq/kg after 20 days). The NIR spectra were recorded between 1000 and 2500 nm by using a Fourier Transform NIR spectrometer, using an external probe. Measurements were done directly in situ on the product, on the ground samples, and on the extracted fat phase. The analysis of NIR spectral data by PLS statistical methods demonstrated some correlation trends (R2 = 0.575–0.897; RMSEC = 17–55%) for the products having a significant increase in PV. It was not possible to propose predictive models to calculate the oxidation rate.
Monitoring of headspace volatiles in milk‐cereal‐based liquid infant foods during storage
Authors: García‐Llatas Guadalupe , Lagarda María Jesús , Clemente Gonzalo , Farré Rosaura
Published: December 2006

The effect of storage (time and temperature) on the evolution of pentanal, hexanal, heptanal and pentane as volatile lipid oxidation products in two liquid ready‐to‐eat milk‐cereal‐based infant foods was studied. An SPME‐GC method was used to this effect. Samples were stored for 9 months at 25, 30 and 37 °C and tested eight times during this period. Freshly produced infant foods contained pentanal, hexanal and heptanal (mean values: 10.71, 71.5 and 1.2 µg/kg, respectively), which decreased during the first 3 months of storage, although from the fourth month onwards no significant differences among storage times were found. Aldehyde content was inversely proportional to storage temperature. Pentane content was directly proportional to storage temperature and increased (19.9 µg/kg at zero time) over all months of storage up to 43.1 µg/kg.
New FATB thioesterases from a high‐laurate Cuphea species: Functional and complementation analyses
Authors: Filichkin Sergei A. , Slabaugh Mary B. , Knapp Steven J.
Published: December 2006

The New World genus Cuphea is a rich source of genes encoding enzymes specialized for seed‐specific synthesis of short‐ and medium‐chain fatty acids (FA). We isolated and characterized two new acyl‐acyl carrier protein (ACP) thioesterase (TE) cDNA, CcFATB1 and CcFATB2, from developing seeds of C. calophylla var. mesostemon. Cuphea calophylla is one of several species in the genus specializing in the synthesis of lauric acid (12:0). Phylogenetic clustering classified CcFATB1 and CcFATB2 as medium‐ and long‐chain FATB TE, respectively. Gene expression analysis indicated that CcFATB1 was seed specific and CcFATB2 was ubiquitous. Overexpression of CcFATB1 in developing seeds of Arabidopsis partially redirected FA synthesis toward medium‐chain FA (12:0, 14:0, and 16:0). Laurate synthesis was preferentially increased by co‐expressing CcFATB1 and CwKAS A1, a medium‐chain‐specific ketoacyl‐ACP synthase (KAS) from another 12:0‐rich species, C. wrightii. Overexpression of CcFATB1 cDNA complemented the low‐palmitate (16:0) but not the low‐stearate (18:0) phenotype in leaves and seeds of an Arabidopsis fatb‐2 mutant, whereas CcFATB2 restored both long‐chain FA. The investigated Cuphea species provide a diverse source of seed‐specific FATB and KAS genes for combinatorial manipulation of medium‐chain FA content in oilseed plants.
Process optimization of oxidative coupling of methane for ethylene production using response surface methodology
Authors: Thien Chua Yen , Mohamed Abdul Rahman , Bhatia Subhash
Published: December 2006

The statistical design of experiments (DoE) was used in the process study of oxidative coupling of methane (OCM) over NaWMn/SiO2 catalyst. A set of factors with a certain range was screened using factorial design with respect to three responses: methane conversion, C2+ products selectivity and ethylene/ethane ratio. The variances were analyzed and the interaction effects of the process parameters were evaluated. With the understanding of the process, the optimization of the process was further studied using response surface methodology coupled with central composite design (CCD). The optimum conditions were obtained as reaction temperature = 850 °C, gas hourly space velocity = 23 947 cm3 g−1 h−1, catalyst pretreatment period = 2 h, dilution ratio = 0.2 and CH4/O2 ratio = 7. 40.55% of methane conversion and 79.51% of C2+ product selectivity were obtained under these optimum conditions. Experimental runs under optimum conditions were repeated and compared with the simulated values obtained from the model. There was good agreement between the experimental and simulated values. Copyright © 2007 Society of Chemical Industry
The use of circular surface aerators in wastewater treatment tanks
Authors: Rao Achanta Ramakrishna , Kumar Bimlesh
Published: December 2006

Aeration experiments were conducted in different sized baffled and unbaffled circular surface aeration tanks to study their relative performance on oxygen transfer process while aerating the same volume of water. Experiments were carried out with the objective of ascertaining the effect of baffle on oxygen transfer coefficient k. Simulation equations govern the oxygen transfer coefficient with the theoretical power per unit volume, X and actual power per unit volume, PV. It has been found that, for any given X, circular tanks with baffle produce higher values of k than unbaffled circular tanks, but in terms of actual power consumption unbaffled tanks consume less power when compared to baffled circular tanks to achieve the same value of k. It has been found that in terms of energy consumption, ε, baffled tanks consume more energy than unbaffled tanks at any value of X. This suggests that the unbaffled circular tank gives a better performance as far as energy consumption is concerned and hence better economy. An example illustrating the energy conservation to aerate the same volume of water in both types of aerators is given. Copyright © 2007 Society of Chemical Industry
PCR survey of hox genes in the goldfish Carassius auratus auratus
Authors: Luo Jing , Stadler Peter F. , He Shunping , Meyer Axel
Published: December 2006

A tetraploidization event took place in the cyprinid lineage leading to goldfishes about 15 million years ago. A PCR survey for Hox genes in the goldfish Carassius auratus auratus (Actinopterygii: Cyprinidae) was performed to assess the consequences of this genome duplication. Not surprisingly, the genomic organization of the Hox gene clusters of goldfish is similar to that of the closely related zebrafish (Danio rerio). However, the goldfish exhibits a much larger number of recent pseudogenes, which are characterized by indels. These findings are consistent with the hypothesis that dosage effects cause selection pressure to rapidly silence crucial developmental regulators after a tetraploidization event. J. Exp. Zool. (Mol. Dev. Evol.) 308B:250–258, 2007. © 2006 Wiley‐Liss, Inc.
Identification and intermodel comparison of seasonal circulation patterns over North America
Authors: Vrac M. , Hayhoe K. , Stein M.
Published: December 2006

Shifts in the frequency of atmospheric circulation patterns throughout the year can characterize seasonality and provide a means to evaluate the ability of atmosphere‐ocean general circulation models (AOGCMs) to reproduce key dynamical structures influencing regional climate. However, the identified characteristics of these patterns can depend on the clustering method used, the physical properties of the model generating the circulation fields, and even their spatial scale. Using two statistical clustering methods, a mixture model and a hierarchical method, we show that these factors can result in distinctly different atmospheric patterns characterizing seasonal circulation over eastern North America based on NCEP and ERA‐40 geopotential height and sea level pressure (SLP) fields. Consistency is improved through constraining the number of clusters at each level to 4 or 5, and using the mixture model method. In general, this method tends to produce more consistent results across the various datasets and is more sensitive to day‐to‐day variations in pattern frequencies than the traditional hierarchical method. Applying the mixture method to PCM and CCSM3 simulations reveals some clear differences relative to reanalysis‐based patterns. In particular, the AOGCMs do not reproduce the observed duration and/or location of summer, with seasonal shifts (PCM) and summer extensions (CCSM) that are strongest at lower levels. However, taking into account the uncertainty introduced by the different factors, these AOGCMs do successfully capture many of the observed large‐scale drivers of seasonality. These results lend support to circulation‐based downscaling, but also highlight some systematic model biases, and hence the ongoing potential for improvements in model parameterization and dynamics. Copyright © 2006 Royal Meteorological Society
An algorithm to determine a dipole current in a sphere
Authors: Rim Kyung Soo , Yun Beong In , Chung Soon‐Yeong
Published: December 2006

Suppose a spherical conductor has a single dipole. If it is assumed that the direction of current is perpendicular to the location of dipole, then we prove that the dipole can be obtained as an exact form from the induced magnetic field and provide an easy algorithm to locate the dipole from the samples of a magnetic field outside the sphere without using any series approximation. A numerical implementation is also presented. Copyright © 2006 John Wiley & Sons, Ltd.
Cdc42 is implicated in polarity during meiotic resumption and blastocyst formation in the mouse
Authors: Cui Xiang‐Shun , Li Xing‐Yu , Kim Nam‐Hyung
Published: December 2006

Cell division cycle 42 (Cdc42), a member of the Rho family of small guanosine triphosphatase (GTPase) proteins, regulates multiple cell functions, including: motility, proliferation, apoptosis, and cell morphology. In order to obtain insight into the role of Cdc42 in meiotic resumption and embryo development, we first evaluated its gene expression levels in mouse oocytes and embryos during in vitro development. Quantitative reverse transcription‐polymerase chain reaction (RT‐PCR) revealed high‐expression levels in GV stage oocytes that steadily decreased up to the 2‐cell (2C) stage embryo, and then expression increased during morulae and blastocyst formation. Indirect Immunocytochemistry also showed protein synthesis of CDC42 in the mouse oocytes and early embryos. Introducing small interference RNA (siRNA) of Cdc42 into germinal vesicle stage oocytes or zygotes specifically reduced both mRNA expression and protein synthesis of CDC42 in in vitro developed metaphase II oocytes and early embryos. Meiotic maturation and cytoskeleton assembly were significantly altered following siRNA injection into germinal vesicle stage oocytes. Injection of siRNA into the zygote did not affect cleavage or cell numbers in morulae, but significantly decreased in vitro development to the morula or blastocyst. These findings suggest that gene expression of Cdc42 is involved in meiotic resumption and blastocyst formation in the mouse, possibly through maintaining polarity. Mol. Reprod. Dev. 74: 785–794, 2007. © 2006 Wiley‐Liss, Inc.
Improvement of transgenic cloning efficiencies by culturing recipient oocytes and donor cells with antioxidant vitamins in cattle
Authors: Wongsrikeao Pimprapar , Nagai Takashi , Agung Budiyanto , Taniguchi Masayasu , Kunishi Miho , Suto Shizuyo , Otoi Takeshige
Published: December 2006

The present study was conducted to investigate effects of antioxidants during maturation culture of recipient oocytes and/or culture of gene‐transfected donor cells on the meiotic competence of recipient oocytes, and the developmental competence and quality of the reconstructed embryos after nuclear transfer (NT) in cattle. Gene‐transfected donor cells had negative effects on the proportions of blastocyst formation, total cell numbers, and DNA fragmentation indices of reconstructed embryos. Supplementation of either vitamin E (α‐tocopherol: 100 µM) or vitamin C (ascorbic acid: 100 µM) during maturation culture significantly enhanced the cytoplasmic maturation of oocytes and subsequent development of embryos reconstructed with the oocytes and gene‐transfected donor cells, but did not have synergistic effects. The supplementation of vitamin E during maturation culture of recipient oocytes increased the proportions of fusion and blastocyst formation of gene‐transfected NT embryos, in which the proportions were similar to those of nontransfected NT embryos. When the gene‐transfected donor cells that had been cultured with 0, 50, or 100 µM of vitamin E were transferred into recipient oocytes matured with vitamin E (100 µM), 50 µM of vitamin E increased the proportion of blastocyst formation and reduced the index of DNA fragmentation of blastocysts. In conclusion, gene‐transfected donor cells have negatively influenced the NT outcome. Supplementation of vitamin E during both recipient oocyte maturation and donor cell culture enhanced the blastocyst formation and efficiently blocked DNA damage in transgenic NT embryos. Mol. Reprod. Dev. 74: 694–702, 2007. © 2006 Wiley‐Liss, Inc.
Rabbit oviductal glycoprotein 1 gene: Genomic organization polymorphism analysis and mRNA expression
Authors: Merchán Maribel , Peiró Rosa , Santacreu M. Antonia , Francino Olga , Folch Josep M.
Published: December 2006

The OVGP1 is an oviductal glycoprotein that has positive effects on fertilization and early embryo development. We have amplified and sequenced the rabbit OVGP1 gene, which spans 13 kb and it is formed by 11 exons and 10 introns. To find polymorphisms, a region encompassing the promoter to intron 1 has been sequenced in 22 rabbits of the H, V, R, and A Spanish lines. We have identified five SNPs and one triallelic microsatellite in the promoter region, and three SNPs and one dinucleotide INDEL in intron 1. The 10 polymorphic sites cosegregate forming two haplotypes. The allelic frequencies of the microsatellite have been analyzed in 98 rabbits belonging to the four lines and the three alleles were found in all the lines. The relative quantification of the OVGP1 mRNA in liver, kidneys, lungs, skeletal muscle, ovary, uterus, and oviduct reveals that the OVGP1 expression in the oviduct is 5,500 higher than in the uterus or ovary, whereas a low level of basal expression is detected in non‐reproductive tissues. We have also compared the mRNA expression between samples of oviducts taken from non‐mated rabbit and samples of oviducts at different stages of the early pregnancy, but no significant differences were found. Mol. Reprod. Dev. 74: 687–693, 2007. © 2006 Wiley‐Liss, Inc.
Development and pattern of mRNA relative abundance of bovine embryos cultured in the isolated mouse oviduct in organ culture
Authors: Rizos D. , Pintado B. , de la Fuente J. , Lonergan P. , Gutiérrez‐Adán A.
Published: December 2006

The aim of this study was to examine the development of bovine zygotes in isolated mouse oviducts (IMO) and the quality of the blastocysts produced. In vitro produced bovine zygotes were transferred into the ampullae of the IMO and cultured in SOF or KSOM. Control embryos were cultured in droplets of the same media. Following 6 days of culture, blastocysts were processed for nuclei counts or mRNA abundance. Culture in the IMO did not affect the proportion of zygotes developing to the blastocyst stage compared to the respective control droplets (SOF: 17.7 ± 3.2% vs. 18.8 ± 2.7%; KSOM: 20.7 ± 2.6% vs. 22.2 ± 2.8%). Culture in the IMO in KSOM resulted in an increased number of inner cell mass (ICM) nuclei; however, total nuclei number or incidence of apoptosis was unaffected. Culture in the IMO in SOF resulted in an increase (P < 0.05) in abundance of transcripts in blastocysts for Oct‐4 and SOX, and reduced abundance of Glut‐1, Na/K, Cx43, and survivin compared to blastocysts derived from culture in SOF alone. In contrast, culture in the IMO in KSOM resulted in increased abundance of transcripts for Glut‐1, Cx43, Oct‐4, and survivin and reduced expression of Na/K and SOX compared to KSOM alone. Transcripts for G6PDH, IFN‐τ, and E‐Cad were unaffected. These data confirm that the IMO is capable of supporting development of bovine embryos. Depending on the basal medium used, the pattern of transcript abundance in embryos derived from the IMO is similar to that of in vivo derived embryos. Mol. Reprod. Dev. 74: 716–723, 2007. © 2006 Wiley‐Liss, Inc.
Phosphatidylinositol 3‐kinase pathway regulates sperm viability but not capacitation on boar spermatozoa
Authors: Aparicio I.M. , Bragado M.J. , Gil M.C. , Garcia‐Herreros M. , Gonzalez‐Fernandez L. , Tapia J.A. , Garcia‐Marin L.J.
Published: December 2006

Phosphatidylinositol 3‐kinase (PI3‐K) plays an important role in cell survival in somatic cells and recent data pointed out a role for this kinase in sperm capacitation and acrosome reaction (AR). This study was undertaken to evaluate the role of PI3‐K pathway on porcine spermatozoa capacitation, AR, and viability using two unrelated PI3‐K inhibitors, LY294002 and wortmannin. In boar spermatozoa, we have identified the presence of PDK1, PKB/Akt, and PTEN, three of the main key components of the PI3‐K pathway. Incubation of boar sperm in a capacitating medium (TCM) caused a significant increase in the percentage of capacitated (25 ± 2 to 34 ± 1% P < 0.05, n = 6) and acrosome reacted (1 ± 1 to 11 ± 1% P < 0.01, n = 6) spermatozoa compared with sperm in basal medium (TBM). Inhibition of PI3‐K did affect neither the capacitation status nor AR nor protein p32 tyrosine phosphorylation of boar spermatozoa incubated in TBM or TCM. Boar sperm viability in TBM was significantly decreased by 40 and 20% after pretreatment with LY294002 or wortmannin, respectively. Similar results were observed after incubation of boar spermatozoa in TCM. Treatment of boar spermatozoa with the analog of cAMP, 8Br‐cAMP significantly prevented the reduction on sperm viability. Our results provide evidence for an important role of the PI3‐K pathway in the regulation of boar sperm viability and suggests that other signaling pathways different from PI3‐K must be activated downstream of cAMP to contribute to regulation of sperm viability. Finally, in our conditions the PI3‐K pathway seems not related with boar sperm capacitation or AR. Mol. Reprod. Dev. 74: 1035–1042, 2007. © 2006 Wiley‐Liss, Inc.
Leptin in the bovine corpus luteum: Receptor expression and effects on progesterone production
Authors: Nicklin L.T. , Robinson R.S. , Marsters P. , Campbell B.K. , Mann G.E. , Hunter M.G.
Published: December 2006

In cattle, leptin has been implicated in the control of ovarian function and has been shown to modulate steroid production by theca and granulosa cells in a number of species. However, a direct effect of leptin on bovine luteal function has not been demonstrated. This study was conducted to determine if the leptin receptor (OB‐R) is expressed in the bovine corpus luteum (CL), and to examine the effects of leptin on progesterone production by dispersed luteal cells in vitro. RT‐PCR was used to detect the presence of OB‐R and, more specifically, the long, biologically active isoform (OB‐Rb), in CL, collected on days 2–18 of the oestrous cycle (n = 18). The effects of leptin on progesterone production were investigated in dispersed luteal cells prepared from CL collected on days 5 and 8 (n = 14) of the cycle. The dispersed luteal cells were cultured for 24 hr with recombinant human leptin and/or LR3‐IGF‐1 and/or LH. OB‐Rs, in particular, OB‐Rb, were expressed in the CL at all stages of development. Progesterone production by luteal cells was increased (P < 0.001) by treatment with LH (10 ng/ml) but treatment with leptin alone had no effect. However, in the presence of IGF‐1 (100 ng/ml), leptin (10 ng/ml) caused a significant (P < 0.005) increase in progesterone production. In conclusion, we have shown that the leptin receptor is expressed in the bovine CL and have demonstrated a modulatory effect of leptin on luteal progesterone production in vitro. Mol. Reprod. Dev. 74: 724–729, 2007. © 2006 Wiley‐Liss, Inc.
Polymorphisms of the human PUMILIO2 gene and male sterility
Authors: Kusz K. , Ginter‐Matuszewska B. , Ziolkowska K. , Spik A. , Bierla J. , Jedrzejczak P. , Latos‐Bielenska A. , Pawelczyk L. , Jaruzelska J.
Published: December 2006

The highly conserved Pumilio protein plays crucial roles in fertility of many organisms acting as a repressor of translation, and causing infertility when mutated. Although one of two human Pumilio homologs, PUMILIO2 is expressed mainly in the germ line, its role in mammalian germ cell development has not been reported yet. To shed light on the role of PUMILIO2 in development of the human male germ line, we screened this gene for mutations in 137 patients presenting a variety of phenotypes with spermatogenic failure. The first variant, we identified was a single base substitution within intron 15 (IVS15 + 6G > A). This variant was found in three azoospermic males, the second allele being the wild type. However, this variant was also present among fertile males, as frequently as in the patients. Although location of IVS15 + 6G > A substitution in close proximity to the canonical donor splice site GT, indicates that its influence on splicing cannot be excluded, our preliminary cDNA analysis has not revealed evidence of a splicing abnormality of PUMILIO2 pre‐mRNA carrying this variant. Nevertheless, this study provides new interesting variant containing a donor splice site variant, which can be relevant for understanding of splicing mechanism of mammalian genes. The second variant, c.774 C > T transversion (Y258Y) in exon 6 was found only in one patient, but an influence on PUMILIO2 function is not obvious. Altogether, this study shows that variation in the PUMILIO2 gene is very low and it seems improbable that mutations of this gene significantly contribute to male infertility in humans. Mol. Reprod. Dev. 74: 795–799, 2007. © 2006 Wiley‐Liss, Inc.
One‐pot synthesis of 2‐phenyl‐2‐oxazoline‐containing quasi‐diblock copoly(2‐oxazoline)s under microwave irradiation
Authors: Hoogenboom Richard , Thijs Hanneke M. L. , Fijten Martin W. M. , van Lankvelt Bart M. , Schubert Ulrich S.
Published: December 2006

The microwave‐assisted statistical copolymerization of 2‐phenyl‐2‐oxazoline with 2‐methyl‐2‐oxazoline or 2‐ethyl‐2‐oxazoline is discussed in this contribution. Kinetic studies of these statistical copolymerizations as well as reactivity ratio determinations were performed to investigate the monomer distribution in these copoly(2‐oxazoline)s, demonstrating the formation of quasi‐diblock copolymers. In addition, the synthesis of copolymer series with monomer concentrations ranging from 0 to 100 mol % is described. These copolymer series were characterized with 1H NMR spectroscopy, gas chromatography, and gel permeation chromatography. Moreover, the glass‐transition temperatures and solubility of these copolymers were studied, and this revealing better mixing of poly(2‐methyl‐2‐oxazoline) (pMeOx) with poly(2‐phenyl‐2‐oxazoline) (pPhOx) than poly(2‐ethyl‐2‐oxazoline) (pEtOx) with poly(2‐phenyl‐2‐oxazoline) (pPhOx). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 416–422, 2007.
Determination of miglitol in human plasma by liquid chromatography/tandem mass spectrometry
Authors: Li Xin , Wang Yingwu , Wang Jiang , Fawcett J. Paul , Zhao Limei , Gu Jingkai
Published: December 2006

A rapid and sensitive method for the determination of miglitol in human plasma using voglibose as internal standard has been developed and validated. Samples of plasma were deproteinated with acetonitrile and washed with dichloromethane before being analyzed by reversed‐phase high‐performance liquid chromatography (HPLC). Separation was carried out on a short Nucleosil C18 column (5 µm, 50 × 4.6 mm i.d.) using 10 mmol/L ammonium acetate at 1.0 mL/min as mobile phase. The detector was an Applied Biosystems Sciex API 4000 mass spectrometer using atmospheric pressure chemical ionization (APCI) for ion production. The instrument was operated at unit resolution in the multiple reaction monitoring mode. The assay was linear over the range 5.00–2000 ng/mL with a limit of detection of 1.00 ng/mL. Intra‐ and inter‐day precision were <2.82% and <2.92%, respectively, with accuracy of 93.3–106%. The assay was successfully applied to a clinical pharmacokinetic study of miglitol given as a single oral dose (50 mg) to healthy volunteers. Copyright © 2006 John Wiley & Sons, Ltd.