bluuebunny/crossref_metadata_2025 huggingface dataset:
Patterning the embryonic kidney: BMP signaling mediates the differentiation of the pronephric tubules and duct in Xenopus laevis
Authors: Bracken Christina M. , Mizeracka Karolina , McLaughlin Kelly A.
Published: December 2007

The Bone morphogenetic proteins (BMPs) mediate a wide range of diverse cellular behaviors throughout development. Previous studies implicated an important role for BMP signaling during the differentiation of the definitive mammalian kidney, the metanephros. In order to examine whether BMP signaling also plays an important role during the patterning of earlier renal systems, we examined the development of the earliest nephric system, the pronephros. Using the amphibian model system Xenopus laevis, in combination with reagents designed to inhibit BMP signaling during specific stages of nephric development, we revealed an evolutionarily conserved role for this signaling pathway during renal morphogenesis. Our results demonstrate that conditional BMP inhibition after specification of the pronephric anlagen is completed, but prior to the onset of morphogenesis and differentiation of renal tissues, results in the severe malformation of both the pronephric duct and tubules. Importantly, the effects of BMP signaling on the developing nephron during this developmental window are specific, only affecting the developing duct and tubules, but not the glomus. These data, combined with previous studies examining metanephric development in mice, provide further support that BMP functions to mediate morphogenesis of the specified renal field during vertebrate embryogenesis. Specifically, BMP signaling is required for the differentiation of two types of nephric structures, the pronephric tubules and duct. Developmental Dynamics 237:132–144, 2008. © 2007 Wiley‐Liss, Inc.
Multicellular rosette formation during cell ingression in the avian primitive streak
Authors: Wagstaff Laura J. , Bellett Gemma , Mogensen Mette M. , Münsterberg Andrea
Published: December 2007

Cell movements are a fundamental feature during the development of multi‐cellular organisms. In amniote gastrulation, cells ingress through the primitive streak, which identifies the anterior‐posterior axis of the embryo. We investigated the cytoskeletal architecture during these morphogenetic processes and characterized microtubule organisation in whole chick embryos. This revealed the distribution of cells with polarized and radial microtubule (MT) arrays across different regions of the embryo. Cells in the epiblast usually displayed radial MT‐arrays, while the majority of cells in the primitive streak had polarized MT‐arrays. Within the primitive streak, many cells organized into groups and were arranged in rosette‐like structures with a distinct centre characterized by an accumulation of actin. Extended confocal microscopy and three‐dimensional image reconstruction identified tips of polarized cells that were protruding from the plane of rosettes, usually from the centre. We propose that organization into higher order structures facilitates cell ingression during gastrulation. Developmental Dynamics 237:91–96, 2008. © 2007 Wiley‐Liss, Inc.
Transcriptional profiling of the megabladder mouse: A unique model of bladder dysmorphogenesis
Authors: Singh Sunita , Robinson Melissa , Ismail Ihab , Saha Monalee , Auer Herbert , Kornacker Karl , Robinson Michael L. , Bates Carlton M. , McHugh Kirk M.
Published: December 2007

Recent studies in our lab identified a mutant mouse model of obstructive nephropathy designated mgb for megabladder. Homozygotic mgb mice (mgb−/−) develop lower urinary tract obstruction in utero due to a lack of bladder smooth muscle differentiation. This defect is the result of a random transgene insertion/translocation into chromosomes 11 and 16. Transcriptional profiling identified a significantly over‐expressed cluster of gene products located on the translocated fragment of chromosome 16 including urotensin II‐related peptide (Urp), which was shown to be preferentially over‐expressed in developing mgb−/− bladders. Pathway analysis of mgb microarray data indicated dysregulation of at least 60 gene products associated with smooth muscle development. In conclusion, the results of this study indicate that the molecular pathways controlling normal smooth muscle development are severely altered in mgb−/− bladders, and provide the first evidence that Urp may play a critical role in bladder smooth muscle development. Developmental Dynamics 237:170–186, 2008. © 2007 Wiley‐Liss, Inc.
Myocardin expression during avian embryonic heart development requires the endoderm but is independent of BMP signaling
Authors: Warkman Andrew S. , Yatskievych Tatiana A. , Hardy Katharine M. , Krieg Paul A. , Antin Parker B.
Published: December 2007

Myocardin, a serum response factor cofactor, plays an important role in regulating heart and smooth muscle development. To investigate myocardin function during early stages of heart development, we isolated the chicken orthologue of myocardin and characterized its expression between Hamburger and Hamilton stages 3 and 15. At stage 4, myocardin transcripts are detected in the lateral and extraembryonic mesoderm, become progressively localized to the precardiac mesoderm and the differentiated myocardium and are also seen in smooth muscle cells of the developing vascular plexus. Surprisingly, myocardin expression within the developing chicken embryo precedes that of the homeodomain transcription factor Nkx2.5. Embryonic dissection studies demonstrate that signals from the endoderm are required for myocardin expression within the precardiac mesoderm. However, unlike Nkx2.5, myocardin expression is not regulated by bone morphogenetic protein (BMP) signaling. These results suggest that initial expression of myocardin in the precardiac mesoderm is regulated by a signaling pathway that is parallel to, and independent of, Nkx2.5 expression. Developmental Dynamics 237:216–221, 2008. © 2007 Wiley‐Liss, Inc.
The macroPARP genes parp‐9 and parp‐14 are developmentally and differentially regulated in mouse tissues
Authors: Hakmé Antoinette , Huber Aline , Dollé Pascal , Schreiber Valérie
Published: December 2007

The macroPARPs Parp‐9 and Parp‐14 are macro domain containing poly(ADP‐ribose) polymerases involved in transcriptional regulation in response to immunoregulatory cytokines. Their genes reside in the same locus (16B3), and the Parp‐9 gene lies head‐to‐head and shares its promoter with the gene encoding its partner, Bbap. Here, we provide a detailed analysis of Parp‐9, Parp‐14, and Bbap expression during mouse development and adulthood. Parp‐9 is developmentally regulated, and prominently expressed in the thymus and specific regions of the brain and gut. In adults, highest expression is maintained in the thymus and intestine. Parp‐14 is more weakly expressed, mainly in the thymus during development and in adulthood. In addition, we show that Bbap is essentially coexpressed with Parp‐9 during development and in adult mouse. However, the different levels of their transcripts detected in the developing brain and gut suggest that Bbap and Parp‐9 display both common and independent tissue‐specific regulations. Developmental Dynamics 237:209–215, 2008. © 2007 Wiley‐Liss, Inc.
SMAD expression in the testis: An insight into BMP regulation of spermatogenesis
Authors: Itman Catherine , Loveland Kate Lakoski
Published: December 2007

Bone morphogenetic proteins (BMPs), members of the transforming growth factor‐β superfamily, extensively influence events that establish male fertility, affecting germ cells and somatic cells throughout fetal and postnatal life. BMP signals are relayed by SMAD proteins, transcription factors that translocate to the nucleus upon ligand stimulation. We show that BMP signaling in the testis may be regulated by selective expression of BMP‐responsive and inhibitory SMADs, with expression differing between the first wave and adult spermatogenesis. Smad1, Smad5, Smad8, Smad4, Smad6, and Smad7 expression is ubiquitous during testis development but becomes cell‐specific in the adult. Furthermore, regulated SMAD6 protein expression at the onset of spermatogenesis suggests differential responsiveness of spermatogonial subpopulations to ligands. In vitro, immature Sertoli cells and spermatogonia transduce BMP2 and BMP4 signals by means of SMAD1, SMAD5, and SMAD8. Based on these findings, we extrapolate these data to interpret BMP mutant testis phenotypes in terms of SMAD availability for signal transduction. Developmental Dynamics 237:97–111, 2008. © 2007 Wiley‐Liss, Inc.
Suzuki Aryl Coupling Catalysed by Palladium Bis(phosphane) Pincer Complexes Based on Ferrocene; X‐ray Structure Determination of {PdCl[{2,5‐(tBu2PCH2)2C5H2}Fe(C5H5)]}OTf
Authors: Sheloumov Alexey M. , Tundo Pietro , Dolgushin Fedor M. , Koridze Avthandil A.
Published: December 2007

Palladium P,C,P pincer complexes PdCl[{2,5‐(R2PCH2)2C5H2}Fe(C5H5)] (1, R = iPr; 2, R = tBu) and {PdCl[{2,5‐(tBu2PCH2)2C5H2}Fe(C5H5)]}OTf (3) catalyse Suzuki aryl coupling under homogeneous conditions as well as in multiphase system (triphase system: organic/Aliquat 336/aqueous solvent); the X‐ray structure of complex 3, in which the iron atom is oxidised, has been determined and compared with that of its neutral precursor 2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
New H‐Bonded Complexes and Their Supramolecular Liquid‐Crystalline Organizations
Authors: Pérez Ana , Gimeno Nélida , Vera Francisco , Ros M. Blanca , Serrano José Luis , De la Fuente M. Rosario
Published: December 2007

Different approaches to the design of liquid crystals by using H‐bonds were analyzed. A selection of stilbazoles and pyridine compounds, with one or two chelating positions, were used as H‐acceptors in mixtures with carboxylic acids. The noncovalent complexes in question afforded calamitic mesomorphism (N, SmA and SmC) as well as a lamellar mesophase (SmCP). Additionally, the liquid crystalline behaviour of the new 2‐hydroxy‐ and 2‐aminopyridine compounds as pure materials is also discussed. Useful results concerning the design and stability of noncovalent calamitic and bent‐core liquid crystals are reported. To induce the bent‐core liquid crystalline order, the conformational flexibility around the H‐bond must be controlled. The new liquid crystals were characterized by IR spectroscopy, optical microscopy, calorimetry, X‐ray diffraction and dielectric spectroscopy.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Reactions of Arenediazonium o‐Benzenedisulfonimides with Aliphatic Triorganoindium Compounds
Authors: Barbero Margherita , Cadamuro Silvano , Dughera Stefano , Ghigo Giovanni
Published: December 2007

The reaction of various arenediazonium o‐benzenedisulfonimides with aliphatic triorganoindium compounds is described. Surprisingly, with triethyl‐ or tributylindium we obtained N‐ethyl‐ or N‐butylanilines, respectively. This is the first case in which, at least formally, the reactive site of a diazonium salt is the nitrogen atom directly bonded to the aromatic ring. In contrast, with trimethylindium we obtained only formaldehyde (aryl)hydrazones. In order to explain the difference between trimethyl‐ and triethylindium we have proposed some reaction mechanisms, supported by detailed density functional (DFT) calculations. The possible role of diazene/hydrazone tautomerism initially assumed was discarded and therefore three mechanisms for the key step (nucleophilic addition of the trialkylindium to the N=N double bond of diazene) were studied. For the favoured mechanism there is a difference in the energy barriers of 2 kcal mol–1 between the reactions with trimethyl‐ and triethylindium. This difference is explained on the basis of the different C–In bond energies in the two organometallics and it is assumed to be enough to explain their different behaviour under the experimental conditions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Amperometric Biosensor Based on Immobilization Acetylcholinesterase on Manganese Porphyrin Nanoparticles for Detection of Trichlorfon with Flow‐Injection Analysis System
Authors: Li Xiao‐Hua , Xie Zong‐Hong , Min Hong , Xian Yue‐Zhong , Jin Li‐Tong
Published: December 2007

A highly sensitive amperometric biosensor for the detection of organophosphate pesticides (OPs) is developed. The biosensor was fabricated by immobilized acetylcholinesterase (AChE) on manganese (III) meso‐tetraphenylporphyrin (MnTPP) nanoparticles (NPs)‐modified glassy carbon (GC) electrode. The MnTPP NPs used in this article were synthesized by mixing solvent techniques. AChE enzyme was immobilized on the MnTPP NPs surface by conjugated with chitosan (CHIT). The electrocatalytic activity of MnTPP NPs led to a greatly improved performance for thiocholine (TCh) product detection. The developed AChE‐CHIT/MnTPPNP/GC biosensor integrated with a flow‐injection analysis (FIA) system was used to monitor trichlorfon (typical OP). A wide linear inhibition response for trichlorfon is observed in the range of 1.0 nM–1.0 mM, corresponding to 10–83% inhibition for AChE with a detection limit of 0.5 nM.
Determination of Total Reduced Thiol Levels in Plasma Using a Bromide Substituted Quinone
Authors: Lobo Grace‐Ann M. , Chitre Sneha A. , Rathod Spandan M. , Smith Robert B. , Leslie Ray , Livingstone Callum , Davis James
Published: December 2007

The exploitation of 2‐bromo‐1,4‐naphthoquinone (NQBr) as a selective redox label for the determination of reduced thiol functionalities (RSH) has been investigated. The system is selective for RSH functionality, giving distinct voltammetric signals for glutathione and cysteine but can also be adapted for broad spectrum thiol detection. Ion chromatographic protocols based on conductimetric detection enable total RSH analysis (protein and monomolecular moieties) within human plasma. Bromide released through the reaction can be easily quantified and integrated within normal IC measurements. The efficacy of the approach has been assessed and the response validated through comparison with the standard colorimetric technique.
Electrochemical Studies of an Iron Porphyrin Immobilized on Nb2O5/SiO2 and Its Application for Simultaneous Determination of Dopamine and Ascorbic Acid Using Multivariate Calibration Methodology
Authors: Skeika Tatiane , Marcovicz Crislaine , Nakagaki Shirley , Fujiwara Sérgio Toshio , Wohnrath Karen , Nagata Noemi , Pessoa Christiana A.
Published: December 2007

This paper shows an application of a first generation porphyrin, FeTPPCl 5,10,25,20‐tetraphenylporphyrin iron(III) chloride (FeTPPCl or FeTPP+) immobilized on a inorganic matrix, SiO2/Nb2O5 (niobium oxide grafted on silica gel surface, designated as SiNb) to the preparation of a carbon paste electrode (CPE). The carbon paste modified with a FeTPP+ immobilized on SiO2/Nb2O5 (SiNb), designated as CPE/SiNb/FeTPP, was applied for simultaneous electrochemical determination of dopamine (DA) and ascorbic acid (AA). Because of the overlapping of the voltammetric peaks of DA and AA, the multivariate calibration methodology based on partial least square regression (PLSR) was proposed. The data pre‐treatment used in this process was mean centering and to choose the principal components number a cross validation procedure was used (leave‐one‐out). Five principal components were necessary to obtain the lowest PRESS (prediction residual error sum of squares). The statistics showed that this model explains approximately 95.2% of the variance from the data set. Using this model, high correlation between actual and predicted concentrations was observed, mainly for higher dopamine (maximum relative error of 8%) and ascorbic acid (maximum relative error of 10%) concentrations. For low analytes concentrations the relative error increases to 35% for AA. Considering the similarity of the voltammetric response of the analytes, the results obtained were satisfactory and showed the promissory capability of the CPE/SiNb/FeTPP coupled multivariate calibration methods for simultaneous voltammetric analysis of DA and AA.
Sol‐Gel Derived Potentiometric Sensor for Determination of Vanadyl Ions
Authors: Arvand Majid , Moghimi Majid , Bagherinia Mohammad A.
Published: December 2007

A sol‐gel electrode, based on thiacalix[4]arene as a neutral carrier, was successfully developed for the detection of VO2+ in aqueous solutions. The sol‐gel electrode exhibited linear response with Nernstian slope of 29.3±0.3 mV per decade, within the vanadyl ion concentration ranges 1.0×10−6 – 1.0×10−1 mol dm−3. The sol‐gel electrode shows detection limit of 4.9×10−7 mol dm−3. The influence of membrane composition, the pH of the test solution, and the interfering ions on the electrode performance were investigated. The electrode exhibited good selectivities for a number of alkali, alkaline earth, transition and heavy metal ions. The effect of temperature on the electrode response showed that the temperature higher than 60 °C deteriorates the electrode performance. Application of the electrode for the determination of vanadyl in spiked samples is reported.
Hepatitis B virus precore protein augments genetic immunizations of the truncated hepatitis C virus core in BALB/c mice
Authors: Liao Guoyang , Wang Yue , Chang Jinhai , Bian Tao , Tan Wenjie , Sun Mingbo , Li Weidong , Yang Huijuan , Chen Junying , Zhang Xinwen , Bi Shengli , Omata Masao , Jiang Shude
Published: December 2007

DNA immunization has been used to induce either humoral or cellular immune responses against many antigens, including hepatitis C virus (HCV). In addition, DNA immunizations can be enhanced or modulated at the nucleotide level. Genetic immunizations were examined in BALB/c mice through the use of plasmids and chimeric DNA constructs encoding HCV core proteins and hepatitis B virus (HBV) precore (preC) regions. Plasmids encoding the truncated HCV core induced potent humoral and cellular responses to HCV; pcDNA3.0A-C154 produced a stronger antibody response than pcDNA3.0A-C191 (

P

< 0.01) and pcDNA3.0A-C69 (

P

< 0.05). HBV preC enhanced the humoral and cellular immune responses of BALB/c mice to HCV; however, pcDNA3.0A-C69preC resulted in a weak cytotoxic T lymphocyte (CTL) response. In addition, the humoral and cellular immune responses to HCV of groups immunized with pcDNA3.0A-C154preC and pcDNA3.0A-C191preC plasmids were higher than those of groups immunized with pcDNA3.0A-C154 and pcDNA3.0A-C191.

In vivo

CTL responses verified that mice immunized with preC core fused DNAs showed significantly high specific lysis compared with mice immunized with HCV cores only (

P

< 0.01). In our study, pcDNA3.0A-C154preC led to the highest immune response among all DNA constructs.

Conclusion

: DNA that encodes truncated HCV core proteins may lead to increased immune responses

in vivo

, and these responses may be enhanced by HBV preC. (Hepatology 2007.)
Multiple end‐point analysis reveals cisplatin damage tolerance to be a chemoresistance mechanism in a NSCLC model: Implications for predictive testing
Authors: Almeida Gabriela M. , Duarte Tiago L. , Farmer Peter B. , Steward William P. , Jones George D.D.
Published: December 2007

Systemic chemotherapy is extensively used in cancer therapy, however, for many treatments' response rates are limited. Furthermore, certain regimens are frequently associated with significant morbidity and occasional mortality. Consequently, when alternative options exist, it is desirable to reserve a particular chemotherapy for those patients whose tumours will respond. Therefore, attention is turning to the development of techniques that could provide predictive information regarding a tumour's particular chemosensitivity, as a means of enhancing patient selection for that specific treatment. One approach has been to focus on measures of DNA damage formation and repair as being potentially predictive of cancer cell chemosensitivity, the premise being that higher levels of induced DNA damage (resulting from the chemotherapeutic agents) and/or deficiencies in DNA damage repair are indicative of greater sensitivity. In the present study we have investigated the Comet assay response of a panel of non‐small cell lung cancer cell lines towards cisplatin and found an inverse correlation between sensitivity and damage formation resulting from this agent. Moreover, an inverse correlation was found between resistance and extent of damage repair. Further analysis of multiple alternate cellular end‐points (including cell cycle analysis, apoptosis and gene expression changes) revealed cisplatin damage tolerance to be a chemoresistance mechanism in this model system. This study highlights damage tolerance mechanisms as potentially confounding factors in attempts to develop predictive tests based on measures of genotoxicity. To address this we would argue that a range of multiple end‐points should be analysed to ascertain the “complete predictive picture”. © 2007 Wiley‐Liss, Inc.
p38 MAPK, but not ERK1/2, is critically involved in the cytotoxicity of the novel vascular disrupting agent combretastatin A4
Authors: Quan Haitian , Xu Yongping , Lou Liguang
Published: December 2007

Combretastatin A4 (CA4) is a novel vascular disrupting agent that has promising clinical efficacy because of its ability to inhibit microtubule assembly and subsequently disrupt tumor blood flow. In this study, we demonstrate that mitogen‐activated protein kinases (MAPKs) are critically involved in the cytotoxicity of CA4. CA4 stimulates both extracellular signal‐regulated kinases (ERK1/2) and p38 MAPK in the BEL‐7402 hepatocellular carcinoma cell line in a time‐ and dose‐dependent manner. This stimulation is a result of CA4‐induced microtubule disassembly, which is a reversible process. Reversibility of microtubule disassembly is evidenced by the ability of disassembled microtubules to reassemble just a few hours after CA4 treatment. p38 MAPK, but not ERK1/2, contributes to this microtubule reassembly following CA4 exposure, and only inhibition of p38 MAPK, but not ERK1/2, synergistically enhances CA4‐induced G2/M cell cycle arrest. Consistent with this, p38 MAPK inhibitors such as SB203580 and SB202190 also synergistically enhance the cytotoxicity of CA4 in cells where p38 MAPK is activated by CA4. This enhancement appears to be specific for CA4 because the cytotoxicity of other microtubule‐targeted agents such as paclitaxel, vinorelbine and colchicine was not affected by p38 MAPK inhibitors. These data indicate that p38 MAPK is a potential anticancer target and that the combination of CA4 with p38 MAPK inhibitors may be a novel and promising strategy for cancer therapy. © 2007 Wiley‐Liss, Inc.
Familial clustering of cancer at human papillomavirus‐associated sites according to the Swedish Family‐Cancer Database
Authors: Hussain Shehnaz K. , Sundquist Jan , Hemminki Kari
Published: December 2007

Familial aggregation of cervical cancer has been demonstrated previously, however aggregation of other human papillomavirus‐associated anogenital, upper aerodigestive tract and skin cancers has not been fully characterized. The Swedish Family‐Cancer Database, which contains reliable data on cancer incidence and nuclear family linkages for all residents of Sweden between 1958 and 2004, was used to calculate standardized incidence ratios (SIR) and 95% confidence intervals for offspring site‐specific cancer risks according to site‐specific cancer in sibling and parental probands. Offspring cancer risk was significantly increased when either a sibling or parent was affected at the same site for penile squamous cell carcinoma (SCC, SIR = 7.54), cervical adenocarcinoma (AC, SIR = 2.31), vulvar SCC (SIR = 2.27), skin SCC (SIR = 2.14), rectal AC (SIR = 1.86), in situ cervical SCC (SIR = 1.80), invasive cervical SCC (SIR = 1.77) and upper aerodigestive tract SCC (SIR = 1.57). Significant aggregation on the order of 2‐fold between anogenital cancers at different sites or histologies was also observed. In situ cervical SCC risk in offspring was strongly influenced by siblings affected with oropharyngeal SCC (SIR = 3.17) and tonsillar SCC (SIR = 1.84). Familial skin SCC was largely unassociated with anogenital or upper aerodigestive tract cancer risk in offspring. These data suggest that common host factors exist among individuals affected with anogenital and upper aerodigestive tract cancers. © 2007 Wiley‐Liss, Inc.
Risks of cancer among a cohort of 23,935 men and women with osteoporosis
Authors: McGlynn Katherine A. , Gridley Gloria , Mellemkjaer Lene , Brinton Louise A. , Anderson Kenneth C. , Caporaso Neil E. , Landgren Ola , Olsen Jorgen H.
Published: December 2007

Low hormone levels among persons with osteoporosis may decrease risk of some cancers. Other osteoporosis risk factors, such as smoking and alcohol consumption, however, may increase risk. As these deleterious factors are more often associated with osteoporosis diagnosed prior to age 70 years, cancer risk may be higher in these younger persons than in the general population. To examine this hypothesis, a cohort study of 23,935 persons with osteoporosis was conducted in Denmark. Patients hospitalized with osteoporosis between 1978 and 1993 were identified in the Danish Inpatient Register. Linkage to the Danish Cancer Registry identified all cancer outcomes through 2003. Standardized incidence ratios (SIR) and 95% confidence intervals (95%CI) were calculated to compare cancer incidence in the cohort with that in the general population. Persons diagnosed prior to age 70 years were at increased cancer risk (women: SIR = 1.11, 95%CI = 1.04–1.19; men: SIR = 1.31, 95%CI = 1.13–1.50) due, in part, to increased risks of cancers of the buccal cavity, esophagus, liver, pancreas and lung. Persons diagnosed at ages 70 and older were at decreased risk (women: SIR = 0.91, 95%CI = 0.87–0.96; men: SIR = 0.89, 0.77–1.01) due, in part, to decreased risks of breast, endometrial, colon, rectal and brain cancers in women and prostate cancer in men. These results suggest that risk factors associated with earlier onset osteoporosis may be associated with increased risk of cancer. Conversely, factors associated with later onset osteoporosis may be related to a decreased risk of cancer. © 2007 Wiley‐Liss, Inc.
The use of doxycycline as a protectant against sulphur mustard in HaCaT cells
Authors: Lindsay Christopher D. , Gentilhomme Edgar , Mathieu Jacques D.
Published: December 2007

As part of an ongoing programme on medical countermeasures against the chemical warfare agent sulphur mustard (HD) and set against the background of the involvement of matrix metalloproteinases (MMPs) in the pathology of HD‐induced vesication processes, the potentially beneficial effects of doxycycline on cell attachment was determined in confluent HaCaT cell cultures exposed to HD. Doxycycline was found to inhibit to a significant extent the tendency of HD‐exposed cells to detach from the growth substrate, however, analysis of the metabolic activity of the adherent cells indicated that doxycycline treatment did not maintain cell viability. It was confirmed that apoptosis was the predominant mode of HD‐induced cell death. The results suggested that doxycycline and other MMP inhibitors may have a role to play in therapeutic intervention against HD exposure, but only as part of a combination therapy. The specific value of protease inhibitors in this capacity remains to be determined. Copyright © 2007 John Wiley & Sons, Ltd., and © Crown Copyright 2007, reproduced with the permission of the Controller of HMSO.
A Gibbs free energy correlation for automated docking of carbohydrates
Authors: Hill Anthony D. , Reilly Peter J.
Published: December 2007

Thermodynamic information can be inferred from static atomic configurations. To model the thermodynamics of carbohydrate binding to proteins accurately, a large binding data set has been assembled from the literature. The data set contains information from 262 unique protein–carbohydrate crystal structures for which experimental binding information is known. Hydrogen atoms were added to the structures and training conformations were generated with the automated docking program AutoDock 3.06, resulting in a training set of 225,920 all‐atom conformations. In all, 288 formulations of the AutoDock 3.0 free energy model were trained against the data set, testing each of four alternate methods of computing the van der Waals, solvation, and hydrogen‐bonding energetic components. The van der Waals parameters from AutoDock 1 produced the lowest errors, and an entropic model derived from statistical mechanics produced the only models with five physically and statistically significant coefficients. Eight models predict the Gibbs free energy of binding with an error of less than 40% of the error of any similar models previously published. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Parameterization of Ca+2–protein interactions for molecular dynamics simulations
Authors: Project Elad , Nachliel Esther , Gutman Menachem
Published: December 2007

Molecular dynamics simulations of Ca+2 ions near protein were performed with three force fields: GROMOS96, OPLS‐AA, and CHARMM22. The simulations reveal major, force‐field dependent, inconsistencies in the interaction between the Ca+2 ions with the protein. The variations are attributed to the nonbonded parameterizations of the Ca+2‐carboxylates interactions. The simulations results were compared to experimental data, using the Ca+2‐HCOO− equilibrium as a model. The OPLS‐AA force field grossly overestimates the binding affinity of the Ca+2 ions to the carboxylate whereas the GROMOS96 and CHARMM22 force fields underestimate the stability of the complex. Optimization of the Lennard‐Jones parameters for the Ca+2‐carboxylate interactions were carried out, yielding new parameters which reproduce experimental data. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Theoretical study on the OH + CH3NHC(O)OCH3 reaction
Authors: Zhang Hui , Zhang Gui‐Ling , Liu Jing‐Yao , Liu Bo , Yu Xiao‐Yang , Li Ze‐Sheng
Published: December 2007

The multiple‐channel reactions OH + CH3NHC(O)OCH3 → products are investigated by direct dynamics method. The optimized geometries, frequencies, and minimum energy path are all obtained at the MP2/6‐311+G(d,p) level, and energetic information is further refined by the BMC‐CCSD (single‐point) method. The rate constants for every reaction channels, R1, R2, R3, and R4, are calculated by canonical variational transition state theory with small‐curvature tunneling correction over the temperature range 200–1000 K. The total rate constants are in good agreement with the available experimental data and the two‐parameter expression k(T) = 3.95 × 10−12 exp(15.41/T) cm3 molecule−1 s−1 over the temperature range 200–1000 K is given. Our calculations indicate that hydrogen abstraction channels R1 and R2 are the major channels due to the smaller barrier height among four channels considered, and the other two channels to yield CH3NC(O)OCH3 + H2O and CH3NHC(O)(OH)OCH3 + H2O are minor channels over the whole temperature range. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Liquid–liquid extraction of biomolecules: an overview and update of the main techniques
Authors: Mazzola Priscila G , Lopes Andre M , Hasmann Francislene A , Jozala Angela F , Penna Thereza CV , Magalhaes Perola O , Rangel‐Yagui Carlota O , Pessoa Jr Adalberto
Published: December 2007

Two‐phase systems can be exploited in separation science for the extraction/purification of desired biomolecules. This article reviews recent experimental work on the use of aqueous two‐phase polymer systems, two‐phase aqueous micellar systems and reversed micellar systems for the extraction/purification of biomolecules. The experimental partitioning behavior of different biomolecules is reviewed and new results with nisin and lipopolysaccharides are presented. An extensive description of each system is presented, based on the biomolecules behavior and the tools employed to improve their extraction and purification. Copyright © 2007 Society of Chemical Industry
Impact of effective alkali and sulfide profiling on Eucalyptus globulus kraft pulping. Selectivity of the impregnation phase and its effect on final pulping results
Authors: Santiago Ana S , Pascoal Neto C , Vilela Carla
Published: December 2007

BACKGROUND: Eucalyptus globulus is an important wood source for paper production and, in the last few years, great efforts have been made to assess its chemical specificities and improve the kraft pulping efficiency. Despite the existence of several works concerning mostly the kinetics of E. globulus kraft pulping there is a lack of systematic studies on the initial phase of pulping as well as on the impact of effective alkali (EA) charge profiling on the kraft pulping performance of this species. The aim of the present work is to assess the effect of initial effective alkali and sulfide charges on the lignin and carbohydrates removal on the impregnation phase and to investigate the effect of EA splitting charge on the whole E. globulus pulping process efficiency.

RESULTS: When the EA charge at impregnation phase increases, the amount of dissolved wood increases until it reaches a constant value of about 20%. Maximum polysaccharide removal at impregnation phase was about 10% of total wood weight. Glucose removal during impregnation was attributed to the degradation and/or dissolution of E. globulus glucans. For EA charges at impregnation phase higher than ∼15%, xylan retention on wood was roughly constant. Despite the differences found at impregnation phase on the amount of dissolved wood and lignin removal, it was demonstrated that these differences are almost completely attenuated until the end of the kraft pulping process.

CONCLUSION: In the case of E. globulus, for a constant effective alkali charge, alkali profiling does not affect the whole kraft pulping performance. Copyright © 2007 Society of Chemical Industry
Fabrication of macroporous hydrogel membranes using photolithography for enzyme immobilization
Authors: Choi Dongkil , Lee Woojin , Lee Yeol , Kim Dae‐Nyun , Park Jinwon , Koh Won‐Gun
Published: December 2007

BACKGROUND: The main problem when immobilizing enzyme inside hydrogel is the activity loss of the trapped enzymes due to the limitation on diffusion. In this study, macroporous poly(ethylene glycol) (PEG) hydrogel membrane was fabricated using photolithography to enhance the activity of immobilized enzyme.

RESULT: Photopolymerization through the designed photomask produced crosslinked hydrogel with tunnel‐like macropores which were completely opened from top to bottom of the hydrogel membranes. Arrays of pores with 50 µm and 100 µm diameters were successfully created in the hydrogel membranes, and the pore density could be controlled by changing the photomask design. An activity study demonstrated that there was an enhancement of more than 50% in glucose oxidase activity in the macroporous membrane in comparison to the nonporous membrane. The activity of immobilized enzyme could be further enhanced by increasing the pore density of the hydrogel membranes or by using a higher molecular weight PEG.

CONCLUSION: Increased enzymatic activity was observed in macroporous hydrogel membranes compared with nonporous hydrogel membranes due to the higher surface to volume ratio provided by the macroporous structure. Compared with other methods of obtaining porous hydrogel, the proposed method is much simpler and can minimize the deactivation of enzyme. Copyright © 2007 Society of Chemical Industry
Global sensitivity analysis for the determination of parameter importance in the chromatographic purification of polyclonal antibodies
Authors: Chhatre Sunil , Francis Richard , Newcombe Anthony R , Zhou Yuhong , Titchener‐Hooker Nigel , King Josh , Keshavarz‐Moore Eli
Published: December 2007

BACKGROUND: The financial and technical challenges currently being faced by the pharmaceutical industry have prompted the development of computer models that rapidly evaluate manufacturing strategies for commercial‐scale drug production. The utility of a model is enhanced by the application of sensitivity analysis techniques (SA), which seek to quantify the relative importance of different input variables. Among several SA methods available, global sensitivity analysis (GSA) provides a powerful means of ranking inputs based on the contribution that each makes towards the variance of a model. To demonstrate the value of the approach, this paper describes the application of GSA to a mathematical model of the synthetic adsorbent‐based chromatographic capture of antibodies from ovine serum, a strategy being considered by Protherics UK Limited for production of an FDA‐approved rattlesnake anti‐venom.

RESULTS: Results indicated that the binding capacity of the adsorbent for the antibody molecules was the most significant factor influencing their recovery, followed closely by the flowrate at which the ovine serum was applied to the column and then finally the antibody concentration in the feedstock. Together, these accounted for almost 94% of the model variance and hence suggest that these would be the key variables to focus upon during process development.

CONCLUSION: Such data illustrate how GSA enables development studies to be concentrated upon those factors which exert the greatest influence on manufacturing performance. Ultimately, this reduces the size of the design space, making it easier to optimize a process and identify the most suitable operating conditions for large‐scale drug production. Copyright © 2007 Society of Chemical Industry
Removal of sulfur inorganic compounds by a biofilm of sulfate reducing and sulfide oxidizing bacteria in a down‐flow fluidized bed reactor
Authors: Celis‐García Lourdes B , González‐Blanco Gehovana , Meraz Mónica
Published: December 2007

BACKGROUND: Biological sulfate removal is a process based on the biological sulfur cycle that consists of two steps: (1) production of sulfide by sulfate reduction; and (2) biological or physico‐chemical sulfide oxidation to elemental sulfur (S0). The objective of this work was to transform soluble sulfur (sulfate) into insoluble sulfur (elemental sulfur) coupling sulfate reduction and sulfide oxidation in one reactor. To accomplish this, a 2.3 L down‐flow fluidized bed reactor was used. Lactate was supplied as electron donor, sulfate and oxygen (air) were the electron acceptors.

RESULTS: After 55 days of batch operation a biofilm with sulfate reducing and sulfide oxidizing activities was developed over a plastic support. Continuous operation for 90 days at a down‐flow superficial velocity of 7.7 m h−1 and 30 °C, showed that sulfate reduction amounted to 72–77% and carbon removal to 20–31%. Under low aeration rates (2.3 L d−1) 50% of the sulfate was transformed to elemental sulfur, when aeration increased to 5.4 L d−1 elemental sulfur recovery was only 30% and sulfide in the effluent amounted to 27% of the sulfur fed.

CONCLUSION: It was possible to obtain elemental sulfur through a coupled anaerobic/aerobic process in one reactor using lactate, sulfate and oxygen (air) as substrates. The development of a biofilm with sulfate reducing and sulfide oxidizing activities was the key of the process. Copyright © 2007 Society of Chemical Industry
Sorption capacity of a new generation granular activated carbon—Bio‐Sep® bead—and its use in a suspended growth bioreactor
Authors: Lal Manmohan S , Thoma Gregory J , Karim Khursheed
Published: December 2007

BACKGROUND: A new generation granular activated carbon—Bio‐Sep® beads—consist of 25% polymer (Nomex) and 75% powdered activated carbon. The porous structure and high surface area of these beads make them suitable for sorbent in adsorption columns, and for immobilization media in bioreactors. The aim of this study was to study the sorption characteristics of Bio‐Sep® beads for methyl t‐butyl ether (MTBE) and t‐butyl alcohol (TBA), and to demonstrate the advantage of their usage in a suspended growth bioreactor.

RESULTS: The maximum uptake capacity of Bio‐Sep® beads for MTBE and TBA, in the studied concentration range (10–100 mg L−1), was observed to be 9.73 and 6.23 mg g−1, respectively. A 52 h desorption experiment resulted in 13.6–42.2% MTBE and 33–53% TBA desorption corresponding to the initial solid phase concentrations of 1.68–9.73 mg g−1 and 1.41–6.23 mg g−1, respectively. The sorption of TBA on the Bio‐Sep® beads was significantly hindered by the presence of MTBE. The addition of 10 g Bio‐Sep® beads (dry weight) in a suspended growth bioreactor was able to eliminate the inhibitory effect of 150 mg L−1 MTBE.

CONCLUSIONS: At an equilibrium aqueous phase concentration (Ce) of 1 mg L−1, the solid phase concentration (qe) on Bio‐Sep® beads were observed as 1.44 and 0.47 mg g−1 for MTBE and TBA, respectively. The results obtained in this study indicate that Bio‐Sep® beads have reasonable sorption and desorption characteristics, which can be successfully exploited for the removal/degradation of toxic organic pollutants in high rate bioreactors. Copyright © 2007 Society of Chemical Industry
Processing of soybean (Glycine max) extracts in aqueous two‐phase systems as a first step for the potential recovery of recombinant proteins
Authors: Aguilar Oscar , Rito‐Palomares Marco
Published: December 2007

BACKGROUND: The potential use of plants as production systems to establish bioprocesses has been established over the past decade. However, the lack of efficient initial concentration and separation procedures affect the generic acceptance of plants as economically viable systems. In this context the use of aqueous two‐phase systems (ATPS) can provide strategies to facilitate the adoption of plants as a base for bioprocesses. Among the crops, soybeans (Glycine max) represent an attractive alternative since potentially they can produce high levels of recombinant protein. In this paper the processing of fractionated soybean extracts using ATPS is evaluated as a first step to recover recombinant proteins expressed in plants, using β‐glucuronidase (GUS; E.C. 3.2.1.31) as a model protein.

RESULTS: The evaluation of the effect of system parameters provided the conditions under which the contaminant proteins from fractionated soybean extracts and GUS concentrated in opposite phases. A PEG 600/phosphate system comprising 14.5% (w/w) polyethylene‐glycol (PEG), 17.5% (w/w) phosphate, a volume ratio (Vr) equal to 1.0, and a system pH of 7.0 resulted in the potential 83% recovery of GUS from the complex mixture and an increase in purity of 4.5‐fold after ATPS.

CONCLUSIONS: The findings reported here demonstrate the potential of ATPS to process fractionated soybean extract as a first step to isolate and purify a recombinant protein expressed in soybeans. The proposed approach can simplify the way in which recombinant proteins expressed in plants can be recovered. Copyright © 2007 Society of Chemical Industry
Practical approach to protein recovery by countercurrent distribution in aqueous two‐phase systems
Authors: Hernandez‐Mireles Ileana , Benavides Jorge , Rito‐Palomares Marco
Published: December 2007

BACKGROUND: The development of efficient processes that will rapidly deliver new biological products to the market is a key goal in biochemical engineering. The establishment of purification processes that permit the recovery of closely related products is essential. The recovery and purification of these types of products is not a trivial task. The current approach exploiting chromatography techniques demands practical alternatives to address the technical and economic constraints. The potential application of countercurrent distribution in aqueous two‐phase systems (CCD‐ATPS) for the purification of related proteins is an alternative of great potential worth considering.

RESULTS: The evaluation of the potential application of CCD‐ATPS for the recovery of proteins provided conditions under which three model proteins (i.e. bovine serum albumin (BSA), ovalbumin and α‐lactoalbumin) of similar isoelectric point but different molecular size can be separated. Process conditions PEG 1000 13% (w/w), phosphate 14% (w/w) at pH 7.0 and volume ratio of 1.0 resulted, after 32 transfers in CCD, in three distinguishable peaks that corresponded to each of the selected proteins.

CONCLUSIONS: The findings reported here demonstrate a practical strategy that serves as a first step to establishing initial conditions to further exploit the separation of closely related proteins. Copyright © 2007 Society of Chemical Industry
Development of a correlation to study parameters affecting nitrification in a domestic wastewater treatment plant
Authors: Coskuner Gulnur , Jassim Majeed S
Published: December 2007

BACKGROUND: Nitrification performance of an activated sludge reactor treating weak domestic wastewater was investigated for 11 months. Ammonia nitrogen removals were investigated as a function of wastewater composition and operational conditions. Backward elimination experimental design was used to determine the influence of the most important independent variables on NH3‐N removal efficiencies. Influent ammonia and biological oxygen demand (BOD5) concentrations, hydraulic retention time (HRT), mixed liquid suspended solids (MLSS), temperature, pH and dissolved oxygen (DO) concentration were considered as independent variables. This study aimed to find the most important parameters to describe nitrification performance.

RESULTS: The presence of nitrification was confirmed by ammonia and nitrate variations throughout the reactor; ammonia oxidizing bacteria (AOB) populations were determined using a fluorescence in situ hybridization (FISH) method. MLSS concentration, influent BOD5 concentration and temperature were found to be the most influential factors on nitrification performance. The empirical correlation using multiple linear regressions was statistically significant and produced an adjusted coefficient of multiple determinations (R2adj) of 92.5%.

CONCLUSION: Correlation provides a good understanding of the various parameters that affect the nitrification process, and could be extended to other case studies. Using these results, operators can apply proper operational strategies to maintain nitrification in wastewater treatment plants. Copyright © 2007 Society of Chemical Industry
Treatment of coking wastewater by a UBF‐BAF combined process
Authors: Zhu Shunni , Ni Jinren
Published: December 2007

BACKGROUND: Coking wastewater is a major pollutant, produced in large quantities in many countries worldwide. This study investigates the performance of a combined system for treating coking wastewater. The system is based on an upflow blanket filter (UBF) with a biological aerated filter (BAF). Efficiency is assessed according to organic pollutants and nitrogen removal.

RESULTS: It was found that hydraulic retention time (HRT) had a greater influence on the removal efficiency of NH3‐N than chemical oxygen demand (COD). The BAF facilitated simultaneous carbonaceous removal and nitrification, depending on the reactor height. The system removed 81.5% of COD and 96.4% of NH3‐N when the total HRT was 46.7 h (15.4 h for UBF and 31.3 h for BAF). Gas chromatography/mass spectrometry analysis indicated that the main components of the coking wastewater were phenols and nitrogenous heterocyclic compounds. Certain refractory compounds decomposed in the anaerobic section, resulting in the production of intermediates. Although most organics present in the influent were absent from the final effluent, a few residual contaminants could not be fully eliminated by the system.

CONCLUSION: The experimental results show that the present system is feasible for the treatment of coking wastewater. Copyright © 2007 Society of Chemical Industry