bluuebunny/crossref_metadata_2025_split huggingface dataset:
New fadB homologous enzymes and their use in enhanced biosynthesis of medium‐chain‐length polyhydroxyalkanoates in fadB mutant Escherichia coli
Authors: Jae Park Si , Yup Lee Sang 
Published: April 2004

AbstractRecombinant Escherichia coli harboring the medium‐chain‐length (MCL) polyhydroxyalkanoate (PHA) synthase gene has been shown to accumulate MCL‐PHAs from fatty acids when FadB is inactive. However, the enzymes in fadB mutant E. coli responsible for channeling the β‐oxidation intermediates to PHA biosynthesis have not been fully elucidated. Only recently, two enzymes encoded by yfcX and maoC have been found to be partially responsible for this. In this study, we identified five new FadB homologous enzymes in E. coli: PaaG, PaaF, BhbD, SceH, and YdbU, by protein database search, and examined their roles in the biosynthesis of MCL‐PHAs in an fadB mutant E. coli strain. Coexpression of each of these genes along with the Pseudomonas sp. 61‐3 phaC2 gene did not allow synthesis of MCL‐PHA from fatty acid in recombinant E. coli W3110, which has a fully functional β‐oxidation pathway, but allowed MCL‐PHA accumulation in an fadB mutant E. coli WB101. In particular, coexpression of the paaG, paaF, and ydbU genes resulted in a MCL‐PHA production up to 0.37, 0.25, and 0.33 g/L, respectively, from 2 g/L of sodium decanoate, which is more than twice higher than that obtained with E. coli WB101 expressing only the phaC2 gene (0.16 g/L). These results suggest that the newly found FadB homologous enzymes, or at least the paaG, paaF, and ydbU genes, are involved in MCL‐PHA biosynthesis in an fadB mutant E. coli strain and can be employed for the enhanced production of MCL‐PHA. © 2004 Wiley Periodicals, Inc.
Selective precipitation and recovery of xylanase using surfactant and organic solvent
Authors: Shin Youn‐Ok , Wahnon Daphne , Weber Martin E. , Vera Juan H. 
Published: April 2004

AbstractThe selective precipitation of xylanase from an aqueous phase containing mixtures of xylanase and cellulase was studied using an ionic surfactant as precipitating ligand and a polar organic solvent as recovery solvent. Of four ionic surfactants tested, sodium di‐(2‐ethylhexyl) sulfosuccinate (AOT) showed a complete removal of xylanase at pH 4.5. The recovery of xylanase from the xylanase‐AOT complex was a strong function of the type and the volume of the polar solvent and of the concentration of sodium acetate buffer in the final aqueous solution used to solubilize the recovered xylanase. With ethanol as a recovery solvent, a recovery of xylanase activity of 78 ± 10% was obtained. The cellulase activity in the recovered xylanase was below the detection limit. The results demonstrate that an ionic surfactant can recover enzymes from aqueous solutions without loss in their activity. © 2004 Wiley Periodicals, Inc.
Expression of a feedback‐resistant anthranilate synthase in Catharanthus roseus hairy roots provides evidence for tight regulation of terpenoid indole alkaloid levels
Authors: Hughes Erik H. , Hong Seung‐Beom , Gibson Susan I. , Shanks Jacqueline V. , San Ka‐Yiu 
Published: April 2004

AbstractDifferent plant species produce a variety of terpenoid indole alkaloids, which are of interest as plant defensive secondary metabolites and as valuable pharmaceuticals. Although significant progress has been made, the mechanisms regulating the levels of this important class of compounds require continued elucidation. Previous precursor feeding studies have indicated that alkaloid accumulation can be improved during the exponential growth phase of hairy root cultures through enhanced tryptophan availability. To test this relationship, transgenic hairy root cultures of Catharanthus roseus were established with a glucocorticoid‐inducible promoter controlling the expression of an Arabidopsis feedback‐resistant anthranilate synthase alpha subunit. Enzyme assays demonstrated that the Arabidopsis alpha subunit is compatible with the native beta subunit and that anthranilate synthase activity is more resistant to tryptophan inhibition in induced than in uninduced extracts. The metabolic effects of expressing the feedback‐resistant anthranilate synthase alpha subunit were also dramatic. Over a 6‐day induction period during the late exponential growth phase, tryptophan and tryptamine specific yields increased from almost undetectable levels to 2.5 mg/g dry weight and from 25 μg/g to 267 μg/g dry weight, respectively. The greater than 300‐fold increase in tryptophan levels observed in these studies under certain induction conditions compares favorably with the fold increases obtained in previous constitutive expression studies. Despite the large increases in tryptophan and tryptamine, the levels of most terpenoid indole alkaloids were not significantly altered, with the exception of lochnericine, which increased 81% after a 3‐day induction period. These results suggest that terpenoid indole alkaloid levels are tightly controlled. © 2004 Wiley Periodicals, Inc.
Split time‐integration for low Mach number compressible flows
Authors: Lange H. C. de 
Published: April 2004

AbstractIn low‐Mach number flows the time‐integration is usually bounded by the stability of the acoustic fluxes. This poses a restriction to the maximum timestep. Integration of all fluxes on this time‐scale, leads to huge cpu times. To decrease this problem a timestep splitting technique has been developed by which the acoustic, convective and diffusive fluxes are treated separately. The integration of each of the fluxes is bounded by their separate stability criteria. As an example, the time‐integration technique will be applied to a temporally developing mixing layer. The results show that the proposed splitted integration technique, applied at a Mach number of 0.2, reduces the cpu time by about a factor three. Furthermore, it will be shown that the technique may also be applied at low (0.05) Mach number flows. Here, the cpu‐reduction reaches its maximum of about a factor of four. Copyright © 2004 John Wiley & Sons, Ltd.
Solution of two‐dimensional Poisson problems in quadrilateral domains using transfinite Coons interpolation
Authors: Provatidis Christopher G. 
Published: April 2004

AbstractThis paper proposes a global approximation method to solve elliptic boundary value Poisson problems in arbitrary shaped 2‐D domains. Using transfinite interpolation, a symmetric finite element formulation is derived for degrees of freedom arranged mostly along the boundary of the domain. In cases where both Dirichlet and Neumann boundary conditions occur, the numerical solution is based on bivariate Coons interpolation using the boundary only. Furthermore, in case of only Dirichlet boundary conditions and no existing axes of symmetry, it is proposed to use at least one internal point and apply transfinite interpolation. The theory is sustained by five numerical examples applied to domains of square, circular and elliptic shape. Copyright © 2004 John Wiley & Sons, Ltd.
CD8α is an activation marker for a subset of peripheral CD4 T cells
Authors: Kenny Emma , Mason Don , Saoudi Abdelhadi , Pombo Ana , Ramírez Francisco 
Published: April 2004

AbstractRat CD4 T lymphocytes express CD8α upon activation. Here, we show that double‐positive cells express CD8α α homodimers, and we study their phenotype and function. Most activated CD4+ lymphocytes expressing CD8α are recent thymic emigrants. Accordingly, most activated CD4 single‐positive thymocytes express CD8α, and thymectomy and aging decrease the frequency of CD4+CD8α+ lymphocytes. However, CD8 induction is not restricted to CD4+ recent thymic emigrants. CD4+CD8α+ and CD4+CD8α–cells were generated in vitro from naive or from primed donors and, to study their function, were transferred to normal rats. Both cell types helped primary humoral responses, but only CD4+CD8α– cells promoted secondary responses. Thus, memory CD4 T cells mediating antibody responses and some naive CD4+ lymphocytes do not express CD8α. In addition, CD4+CD8α+ cells produce mainly Th1 cytokines while CD4+CD8α– cells produce IL‐10 and showed a sustained proliferative response. Hence, CD8α expressionafter activation distinguishes two distinct CD4 T cell subsets.
Perforin and IFN‐γ do not significantly regulate the virus‐specific CD8+ T cell response in the absence of antiviral effector activity
Authors: Christensen Jeanette E. , Wodarz Dominik , Christensen Jan P. , Thomsen Allan R. 
Published: April 2004

AbstractUsing gene‐targeted mice we have investigated whether perforin and/or interferon‐γ exert a direct regulatory effect on the expansion and contraction of antigen‐specific CD8+ T cells following infection with a virus (vesicular stomatitis virus) which is not controlled through these molecular effector systems. Unlike what has been observed when these molecules are essential for pathogen clearance, neither molecule was found to play an important role in regulating the kinetics of the virus‐specific CD8+ T cell response in the absence of antiviral effector activity.
Fertility pattern does not explain social gradient in breast cancer in denmark
Authors: Danø Hella , Hansen Kasper Daniel , Jensen Per , Petersen Jørgen Holm , Jacobsen Rune , Ewertz Marianne , Lynge Elsebeth 
Published: April 2004

AbstractThe present study was undertaken to assess the impact of reproductive behavior on the social class gradient in breast cancer occurrence in Denmark. Objectives were to study whether the gradient across socioeconomic groups could be explained by fertility differences, whether the gradient across educational groups could be explained by fertility differences and whether the effect of socioeconomic group on breast cancer incidence and mortality could be explained by education and vice versa. We studied 674,084 women aged 20–39 at the census on 9 November 1970 for whom we had complete data on fertility history. The cohort was followed up for breast cancer incidence and mortality until 8 November 1998. Fertility history varied considerably across socioeconomic group, where 38% of the academics were childless at the age of 30, in contrast to only 8% of women in agriculture. The academics had the highest risk of breast cancer and women in agriculture had the lowest risk. For incidence, the gradient in the relative risks was 1.74, which changed to 1.49 when fertility history was incorporated and to 1.29 when school education was also taken into account. For school education, women with ≥ 12 years of schooling had the highest risk and women with ≤ 7 years of schooling had the lowest risk. For incidence, the gradient in the relative risk was 1.38, which changed to 1.26 when fertility history was incorporated and to 1.22 when socioeconomic group was also taken into account. © 2004 Wiley‐Liss, Inc.
Intratumor chromosomal heterogeneity in advanced carcinomas of the uterine cervix
Authors: Lyng Heidi , Beigi Marzieh , Svendsrud Debbie H. , Brustugun Odd T. , Stokke Trond , Kristensen Gunnar B. , Sundfør Kolbein , Skjønsberg Ane , De Angelis Paula M. 
Published: April 2004

AbstractIntratumor heterogeneity in chromosomal aberrations is believed to represent a major challenge in the treatment of cancer. The aim of our work was to assess the chromosomal heterogeneity of advanced cervical carcinomas and to distinguish aberrations that had occurred at a late stage of the disease from early events. A total of 55 biopsies, sampled from 2–4 different sites within 20 tumors, were analyzed by use of comparative genomic hybridization. Heterogeneous aberrations were identified as those present in at least 1 of the biopsies and which were not seen, nor seen as a tendency, in the others of the same tumor. The homogeneous aberrations were those seen in all biopsies of the tumor. The most frequent homogeneous aberrations were gain of 3q (65%), 20q (65%) and 5p (50%), indicating that these are early events in the development of the disease. Chromosomal heterogeneity was observed in 11 tumors. The most frequent heterogeneous aberrations were loss of 4p14–q25 (60% of 10 cases with this aberration), and gain of 2p22–pter (50% of 6 cases), 11qcen–q13 (33% of 9 cases) and 8q (27% of 11 cases), suggesting that these events promote progression at a later stage. Many of the heterogeneous regions contained genes known to influence the prognosis of cervical cancer, such as 7p (EGFR), 8q (c‐MYC), 11qcen‐q13 (CCND1) and 17q (ERBB2). Three evolution sequences for the subpopulations in the heterogeneous tumors were identified: a serial, a parallel and a mixed sequence. In 2 tumors with a serial sequence, it was indicated that the aberrations +8 and −X had occurred after the other heterogeneous aberrations and hence were the aberrations most recently formed. Our results suggest pronounced chromosomal instability in advanced cervical carcinomas. Moreover, aggressive and treatment‐resistant subpopulations may emerge at a late stage and possibly contribute to a poor prognosis of the advanced stages. © 2004 Wiley‐Liss, Inc.
Carcinoembryonic antigen induction of IL‐10 and IL‐6 inhibits hepatic ischemic/reperfusion injury to colorectal carcinoma cells
Authors: Jessup John Milburn , Laguinge Luciana , Lin Shuling , Samara Raed , Aufman Kimberly , Battle Paul , Frantz Marilyn , Edmiston Kirsten H. , Thomas Peter 
Published: April 2004

AbstractTumor cells cause ischemia/reperfusion (I/R) injury as they arrest within the hepatic microvasculature with the production of nitric oxide (NO) and reactive oxygen species (ROS) that kill both host liver and implanting tumor cells. Carcinoembryonic antigen (CEA) both facilitates the survival of experimental metastasis to nude mouse liver by weakly metastatic human colorectal carcinomas (CRCs) and induces the release of the proinflammatory cytokine IL‐6. We hypothesized that CEA also stimulates the release of the antiinflammatory cytokine IL‐10 causing inhibition of the toxicity of hepatic I/R injury and indirect stimulation of tumor cell colonization of the liver. Intravenous injection of CEA produced more than 1 ng/ml of IL‐10 in the systemic circulation within 1 hr which subsided by 8 hr. The IL‐10 response is specific to CEA since the pentapeptide sequence in CEA that binds to the CEA receptor stimulated isolated Kupffer cells to produce IL‐10. IL‐10, but not IL‐6, increased the survival of weakly metastatic CRC cocultured with ischemic‐reoxygenated liver fragments but did not affect the survival of CRC exposed to oxidative stress in the absence of any host cells. CEA, IL‐6 and IL‐10 pretreatment reduced expression of iNOS but only CEA and IL‐10 strongly inhibited NO and total reactive species production by ischemic‐rexoygenated liver. IL‐6 was toxic to CRC exposed to oxidative stress while IL‐10 did not have a direct effect on CRC. Thus, CEA stimulates production of IL‐10 that may enhance metastasis by promoting the ability of circulating CRC cells to survive the I/R injury of implantation. © 2004 Wiley‐Liss, Inc.
Oral lactoferrin inhibits growth of established tumors and potentiates conventional chemotherapy
Authors: Varadhachary Atul , Wolf Jeffrey S. , Petrak Karel , O'Malley Bert W. , Spadaro Michela , Curcio Claudia , Forni Guido , Pericle Federica 
Published: April 2004

AbstractIn this work, we investigated the anticancer activity of orally administered recombinant human lactoferrin (rhLF) alone and in combination with chemotherapy in tumor‐bearing mice. rhLF inhibited the growth of squamous cell carcinoma (O12) tumors in T cell–immunocompromised nu/nu mice by 80% when administered at 1,000 mg/kg (2.9 g/m2) by oral gavage twice daily for 8 days (p < 0.001). Similar activity was observed in syngeneic, immunocompetent BALB/c mice, where orally administered rhLF (1,000 mg/kg, 2.9 g/m2 once daily) halted the growth of mammary adenocarcinoma TUBO. Oral rhLF (200 mg/kg, 0.57 g/m2) was also used alone and in combination with cis‐platinum (5 mg/kg) to treat head‐and‐neck squamous cell carcinoma in a syngeneic murine model. Monotherapy with oral rhLF or cis‐platinum caused 61% or 66% tumor growth inhibition over placebo, respectively. Mice receiving both therapies showed 79% growth inhibition, a statistically significant improvement over each drug alone. We then demonstrated that administration of oral rhLF (300 mg/kg, 0.86 g/m2) to tumor‐bearing or naive mice resulted in (i) significantly increased production of IL‐18 in the intestinal tract, (ii) systemic NK cell activation and (iii) circulating CD8+ T‐cell expansion. These data suggest that oral rhLF is an immunomodulatory agent active against cancer as a single agent and in combination chemotherapy, exerting its systemic effect through stimulation of IL‐18 and other cytokines in the gut enterocytes. rhLF has been administered orally to 211 people without a single serious drug‐related adverse event. Thus, rhLF shows promise as a safe and well‐tolerated novel immunomodulatory anticancer agent. © 2004 Wiley‐Liss, Inc.
Do Protozoa Control the Elimination of Vibrio choleraein Brackish Water?
Authors: Martínez Pérez María Elena , Macek Miroslav , Castro Galván María Teresa 
Published: April 2004

AbstractElimination of inoculated Vibrio cholerae (≥107 cells ml−1) within a brackish water bacteria assemblage (Mecoacán Lagoon, State of Tabasco, Mexico) was studied in laboratory microcosms with filtration‐fractionated water. Feeding of a ciliate, Cyclidium glaucoma was evaluated using fluorescently labelled V. cholerae o1. Even though V. cholerae was not exploited as the major food source, ciliates were able to eliminate it efficiently. An addition of chitin directly supported the growth of bacteria, although not so much of V. cholerae, and indirectly the growth of the protistan assemblage. Generally, the changes in a bacterial assemblage structure were the most important in V. cholerae elimination.
Determinants of Benthic Diatom Community Structurein Boreal Streams: the Role of Environmental and Spatial Factors at Different Scales
Authors: Soininen Janne 
Published: April 2004

AbstractBenthic diatoms were sampled at 197 sites in Finnish boreal streams. The diatom distribution patterns were related to environmental and spatial factors at three spatial scales using Canonical Correspondence Analysis (CCA). The results emphasized the predominance of chemical‐constituent concentration and ion composition on structuring benthic diatom communities in running waters. Within a river system, physical factors had notable influence on diatom community structure reflecting mainly only minor changes in water chemistry within a watershed. Partial CCA revealed that pure spatial component explained ca. 20% of explainable variation in diatom data at each of the three scales. Environmental factors captured 53–78% of explained variation in species data at ecoregion and river system level. According to Procrustean Randomization Test, spatial coordinates of the study sites and patterns in diatom community structure were strongly concordant (m2 = 0.862, p = 0.001) across the largest spatial scale. Similarly, at smaller spatial scales in southern and central Finland, congruence was significant. These data support the view that diatom communities exhibit a rather strong spatial component especially at largest, national scale.
Identification of Pseudomonas aeruginosa, Burkholderia cepacia complex, and Stenotrophomonas maltophilia in respiratory samples from cystic fibrosis patients using multiplex PCR
Authors: da Silva Filho Luiz V.F. , Tateno Adriana F. , Velloso Luciana de F. , Levi José E. , Fernandes Silvana , Bento Christina N.O. , Rodrigues Joaquim C. , Ramos Sonia R.T.S. 
Published: April 2004

AbstractA multiplex PCR method was developed to identify P. aeruginosa, B. cepacia complex, and S. maltophilia directly in sputum and oropharyngeal samples from CF patients. One hundred and six patients (53 male, and 53 female) attending our pulmonology clinic were studied from September 2000–April 2001. Two hundred and fifty‐seven samples were cultured in selective media and submitted to multiplex PCR reactions, using three primer pairs targeting specific genomic sequences of each species, with an additional primer pair targeting a stretch of ribosomal 16S DNA, universal for bacteria, to act as a control. P. aeruginosa was isolated by culture in 56% of samples, B. cepacia complex in 4.3%, and S. maltophilia in 2.7%, while multiplex PCR identified P. aeruginosa in 78.7%, B. cepacia complex in 3.9%, and S. maltophilia in 3.1% of samples. Multiplex PCR results were verified by PCR reactions using different species‐specific primers described in the literature and DNA sequencing of amplicons from a few samples. Comparing to culture results, the sensitivity and specificity values of multiplex PCR for bacterial identification were, respectively, 97.2% and 45.5% for P. aeruginosa, 45.5% and 97.9% for B. cepacia complex, and 40% and 97.6% for S. maltophilia. All 10 multiplex PCR‐positive results for B. cepacia complex were confirmed using other species‐specific primers described in the literature, while this approach confirmed results for S. maltophilia identification in 7/8 samples (87.5%). Sequencing of amplicons from samples culture‐negative but multiplex PCR‐positive for P. aeruginosa and B. cepacia complex confirmed their identity, while minor nucleotide differences among amplicons ruled out the hypothesis of PCR contamination. Pediatr Pulmonol. 2004; 37:537–547. © 2004 Wiley‐Liss, Inc.
Increasing the efficiency of pharmacokinetic sample procurement, preparation and analysis by liquid chromatography/tandem mass spectrometry
Authors: Villa Josephine S. , Cass Robert T. , Karr Dane E. , Adams Stacy M. , Shaw Jeng‐Pyng , Schmidt Donald E. 
Published: April 2004

AbstractThe movement towards a 96‐well format has greatly increased productivity and throughput in bioanalytical laboratories. Improvements in automated sample preparation and analytical methods have further contributed to increased productivity. We have focused on sample collection and transfer to the bioanalyst and have found improvements to the current available methods. The problem of manual transfers and plasma clotting issues can be overcome with the use of microtainers. Specifically, for illustrative purposes, three proprietary Theravance compounds were tested for stability, non‐specific binding, and electrospray ion suppression in microtainers. There were no issues with stability, non‐specific binding or ion suppression for the above compounds even after leaving plasma samples in the microtainers over long periods of time. The microtainers are robot‐compatible and the resulting plasma can be transferred without clotting issues. To date, all in‐house compounds successfully analyzed and tested using the microtainers have mass ranges between 200 and 1800 Da, pKa ranges between 3.8 and 10.3, and logD ranges between −1.7 and 4.2. Once samples are transferred into 96‐well plates, flexibility in preparation and analysis is available. Together with automated sample preparation and the use of liquid chromatography/tandem mass spectrometry (LC/MS/MS) as an analytical tool, the use of microtainers as sample collection tubes and for sample storage saved considerable time, cost and effort in both of our pharmacokinetic (PK) and bioanalytical groups. This in turn has led to an increased efficiency and overall throughput in support of our drug discovery effort. Copyright © 2004 John Wiley & Sons, Ltd.