bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dietary sodium inhibits aqueous copper uptake in rainbow trout(Oncorhynchus mykiss)
Authors: Pyle G. G. , Kamunde C. N. , McDonald D. G. , Wood C. M. 
Published: January 2003

SUMMARYOurs is the first study to demonstrate an influence of dietary sodium on waterborne copper uptake in fish. We examined possible interactions between dietary sodium and the response of freshwater rainbow trout (Oncorhynchus mykiss) to waterborne copper in light of recent evidence of interactions between sodium and copper metabolism in the gills. Trout were maintained for 6 days on one of four diets of increasing sodium concentration (0.25 mmol g-1, 0.51 mmol g-1, 0.76 mmol g-1 and 1.27 mmol g-1, which corresponds to 0.6%, 1.2%, 1.8% and 3% sodium by mass, respectively). At the end of 7 days, fish were exposed for 6 h to waterborne copper spiked with 64Cu to determine if the dietary sodium affected responses to a subsequent short-term waterborne copper exposure. The radiotracer allowed us to distinguish between Cu occurring in fish tissues before the experiment and `newly accumulated' Cu arising from the experimental exposure. Dietary sodium concentrations of 1.8% or 3% reduced newly accumulated copper concentrations in gill (from 93.9 ng g-1in control to 38.9 ng g-1 and 20.0 ng g-1 in fish fed 1.8% or 3% Na+-supplemented diets, respectively), liver (from 64.3 ng g-1 to 23.1 ng g-1 and 7.5 ng g-1,respectively), kidney (from 29.3 ng g-1 to 11.7 ng g-1and 7.8 ng g-1, respectively), plasma (from 64.7 ng g-1to 21.5 ng g-1 and 10.7 ng g-1, respectively) and gut(from 6.8 ng g-1 to 3.4 ng g-1 and 2.2 ng g-1, respectively) by 50.0-88.2%. The 3%Na+-supplemented diets also increased plasma and gut sodium concentrations by 38.1% (from 137.1 μmol g-1 to 189.3 μmol g-1) and 104.3% (from 56.5 μmol g-1 to 115.4 μmol g-1), respectively, relative to fish maintained on untreated diets. Whole body uptake rates of both sodium and copper were significantly reduced,and highly correlated (r=0.97) with one another, in fish fed high-sodium diets relative to controls. Moreover, sodium efflux was 12% and 38% higher in fish fed 1.8% and 3% sodium-enriched diets, respectively. Fish fed high-sodium diets also drank more water, but the contribution of drinking to waterborne copper uptake was negligible. From these results, we speculate that, at least in part, aqueous sodium and copper share a common branchial uptake route, probably through an apical sodium channel. According to this hypothesis, as the channel is downregulated with increasing internal sodium concentrations, both sodium and copper uptake from the water are inhibited.
Cloning of rainbow trout (Oncorhynchus mykiss) α-actin,myosin regulatory light chain genes and the 5′-flanking region ofα-tropomyosin. Functional assessment of promoters
Authors: Krasnov Aleksei , Teerijoki Heli , Gorodilov Yuri , Mölsä Hannu 
Published: January 2003

SUMMARYWe report PCR cloning of rainbow trout α-actin (α-OnmyAct),myosin regulatory light chain (OnmyMLC2) genes and the 5′-flanking region of α-tropomyosin (α-OnmyTM). Being expressed in skeletal and cardiac muscle, α-OnmyAct was a predominant isoform in trunk muscle of adult rainbow trout. Exon structure of this gene was identical to all known vertebrate skeletal and to some of the cardiac α-Act genes. Two distinct OnmyMLC2 promoters were cloned and both included transposon-like sequences. The coding part of OnmyMLC2 consisted of seven exons whose length was typical for vertebrate MLC2 genes. The upstream regions of α-OnmyAct and OnmyMLC2 included a TATA box and a number of putative regulatory motifs(E-boxes in all three sequences and CArG-boxes in α-OnmyAct), whereas there were no canonical motifs in the α-OnmyTM promoter. LacZ reporter gene was fused with the 5′-flanking regions of α-OnmyAct, two OnmyMLC2 genes and α-OnmyTM promoters. These constructs were transferred into rainbow trout eggs. At the stage of 39 somite pairs, LacZ reporter was detected in the myotomes, neural plate and neural crest, brain and yolk syncytial layer of all analysed embryos. α-OnmyTMLacZ was also expressed in the heart. Functionality of promoters and the α-OnmyAct terminator was confirmed in rainbow trout primary embryonic cell cultures. We cloned rainbow trout glucose transporter type I (OnmyGLUT1) into vectors including the α-OnmyAct and OnmyMLC2 promoters and the α-SkAct terminator. Recombinant OnmyGLUT1 transcripts were detected in rainbow trout embryos during somitogenesis.
Volumetric and ionic responses of goldfish hepatocytes to anisotonic exposure and energetic limitation
Authors: Espelt M. V. , Mut P. N. , Amodeo G. , Krumschnabel G. , Schwarzbaum P. J. 
Published: January 2003

SUMMARYThe relationship between cell volume and K+ transmembrane fluxes of goldfish (Carassius auratus) hepatocytes exposed to anisotonic conditions or energetic limitation was studied and compared with the response of hepatocytes from trout (Oncorhynchus mykiss) and rat (Rattus rattus). Cell volume was studied by video- and fluorescence microscopy,while K+ fluxes were assessed by measuring unidirectional 86Rb+ fluxes.In trout and rat hepatocytes, hyposmotic (180 mosmoll-1)exposure at pH 7.45 caused cell swelling followed by a regulatory volume decrease (RVD), a response reported to be mediated by net efflux of KCl and osmotically obliged water. By contrast, goldfish hepatocytes swelled but showed no RVD under these conditions. Although in goldfish hepatocytes a net(86Rb+)K+ efflux could be activated by N-ethylmaleimide, this flux was not, or only partially, activated by hyposmotic swelling (120-180 mosmoll-1).Blockage of glycolysis by iodoacetic acid (IAA) did not alter cell volume in goldfish hepatocytes, whereas in the presence of cyanide (CN-),an inhibitor of oxidative phosphorylation, or CN- plus IAA(CN-+IAA), cell volume decreased by 3-7%. Although in goldfish hepatocytes, energetic limitation had no effect on(86Rb+)K+ efflux,(86Rb+)K+ influx decreased by 57-66% in the presence of CN- and CN-+IAA but was not significantly altered by IAA alone. Intracellular K+ loss after 20 min of exposure to CN- and CN-+IAA amounted to only 3% of the total intracellular K+.Collectively, these observations suggest that goldfish hepatocytes, unlike hepatocytes of anoxia-intolerant species, avoid a decoupling of transmembrane K+ fluxes in response to an osmotic challenge. This may underlie both the inability of swollen cells to undergo RVD but also the capability of anoxic cells to maintain intracellular K+ concentrations that are almost unaltered, thereby prolonging cell survival.
Five-year results of curettage-cryosurgery for 100 consecutive auricular non-melanoma skin cancers
Authors: Nordin Peter , Stenquist Bo 
Published: January 2003

Large excisions or Mohs’ micrographic surgery (MMS) are often the suggested treatments for non-melanoma skin cancers (NMSCs) of the external ear. This five-year follow-up attempts to evaluate whether curettage-cryosurgery could be an alternative therapy for selected auricular NMSCs.One hundred auricular NMSCs, selected at a skin tumour clinic, were treated by a thorough curettage, with different-sized curettes, followed by cryosurgery in a double freeze-thaw cycle. Seventy-seven basal cell carcinomas (BCCs), 13 squamous cell carcinomas (SCCs), six SCCs in situ, and four basosquamous carcinomas were included. The mean diameter of the tumours was 18 mm (range 5–70). Morphoeiform BCCs, recurrent BCCs with fibrotic component, and most of the SCCs were selected for MMS.Seventy-one patients with 81 tumours were followed-up for at least five years with only one recurrence. Nineteen patients with 19 tumours, followed-up for two to four years, died from other causes with no sign of recurrence at their last visit. Patients followed-up for less than two years were excluded. No major problems were registered after treatment. The cosmetic result was good or acceptable in most patients.In carefully selected patients a thorough curettage followed by freezing with liquid nitrogen in a double freeze-thaw cycle could be a safe and inexpensive therapy even for large NMSCs of the external ear.
Predicting information flows in network traffic
Authors: Hinich Melvin J. , Molyneux Robert E. 
Published: January 2003

AbstractIn optimizing information flows in networks, it would be useful to predict aspects of the network traffic. Yet, the notion of predicting network traffic does not appear in the relevant literature reporting analysis of network traffic. This literature is both well developed and skeptical about the value of traditional time series analysis on network data. It has consistently reported three “traffic invariants” in the analysis of network and Internet traffic. This study uses such time series analysis on a day's worth of Internet log data and finds poor support for one of the invariants. In the preliminary analysis, evidence of nonlinearity was discovered in these data and the analysis presented here examines this question further. This study posits that nonlinear events may be a traffic invariant although this hypothesis would have to be investigated further. The appearance of nonlinear structures is important to the question of predicting network traffic because there are currently no methods to predict time series with nonlinear structures. The discovery of nonlinear structures, then, may mean that developing a predictive model is impossible with current techniques. On the other hand, these nonlinearities may result from interactions from other OSI Layers than the one studied.
Open source software development and Lotka's Law: Bibliometric patterns in programming
Authors: Newby Gregory B. , Greenberg Jane , Jones Paul 
Published: January 2003

AbstractThis research applies Lotka's Law to metadata on open source software development. Lotka's Law predicts the proportion of authors at different levels of productivity. Open source software development harnesses the creativity of thousands of programmers worldwide, is important to the progress of the Internet and many other computing environments, and yet has not been widely researched. We examine metadata from the Linux Software Map (LSM), which documents many open source projects, and Sourceforge, one of the largest resources for open source developers. Authoring patterns found are comparable to prior studies of Lotka's Law for scientific and scholarly publishing. Lotka's Law was found to be effective in understanding software development productivity patterns, and offer promise in predicting aggregate behavior of open source developers.
Synthesis of 3‐tert‐butylcatechol by an engineered monooxygenase
Authors: Meyer Andreas , Held Martin , Schmid Andreas , Kohler Hans‐Peter E. , Witholt Bernard 
Published: January 2003

AbstractRecombinant Escherichia coli JM101 was used for the in vivo biocatalytic synthesis of 3‐tert‐butyl‐ catechol. The bacterial strain synthesized the laboratory‐evolved variant HbpAT2 of 2‐hydroxybiphenyl 3‐monooxygenase (HbpA, EC 1.14.13.44) from Pseudomonas azelaica HBP1. The mutant enzyme HbpAT2 is able to hydroxylate 2‐tert‐butylphenol to the corresponding catechol, a reaction that is not catalyzed by the wild‐type enzyme. The biotransformation was performed in a 3‐L bioreactor for 24 h. To mitigate the toxicity of the 2‐tert‐butylphenol starting material, we applied a limited substrate feed. Continuous in situ product removal with the hydrophobic resin Amberlite™ XAD‐4 was used to separate the product from culture broth. In addition, binding to the resin stabilized the product, which was important because 3‐tert‐butylcatechol is very labile in aqueous solution. The productivity of the process was 63 mg L−1 h−1 so that after 24 h, 3.0 g of 3‐tert‐butylcatechol were isolated. Down‐stream processing consisted of two steps. First, bound 2‐tert‐butylphenol and 3‐tert‐butylcatechol were eluted from Amberlite™ XAD‐4 with methanol. Second, the two compounds were separated over neutral aluminum oxide, which selectively binds the produced catechol but not the phenol substrate. The final purity of 3‐tert‐butylcatechol was greater than 98%. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 518–524, 2003.
Optimizing chemotherapy by measuring reversal of P‐glycoprotein activity in plasma membrane vesicles
Authors: Köhler Sabine , Stein Wilfred D. 
Published: January 2003

AbstractThe appearance of multidrug resistance (MDR) of cancer cells is a major obstacle to successful chemotherapy. Several proteins have been identified that pump chemotherapeutic drugs out of cells, thus bringing about MDR. One representative pump is the P‐glycoprotein, whose function can be inhibited by blockers (also known as reversers, modulators or chemosensitizers). In clinical application, many of these blockers are often not effective because they become bound to the plasma of the patients. The extent of plasma binding of the blocker varies in different persons and we have developed a 96‐well kit to assay such inter‐person differences. The assay uses membrane vesicles isolated from a human lymphoblastoid cell line (CEM Col1000). Uptake of rhodamine into the vesicles was measured with different concentrations of the blockers verapamil and XR9576 in presence of human plasma. The reverser XR9576 is nearly 30 times more effective than the classical blocker verapamil, the relevant Km values ranging from 2.66 to 45 nM for XR 9576 and 0.7 to 5.5 μM for verapamil. An even greater difference between these two drugs, nearly 1000‐fold, could be shown also in intact cells by calcein AM uptake experiments. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 507–517, 2003.
Effect of deletion of chitin synthase genes on mycelial morphology and culture viscosity in Aspergillus oryzae
Authors: Müller Christian , Hansen Kim , Szabo Peter , Nielsen Jens 
Published: January 2003

AbstractThe objective of this study was to quantify the effect of disrupting two chitin synthases, chsB and csmA, on the morphology and rheology during batch cultivation of Aspergillus oryzae. The rheological properties were characterized in batch cultivations at different biomass concentrations (from 3.4–22.5 g kg−1 biomass) and the power‐law model adequately described the rheological properties. In the cultivations there were pellets, clumps, and freely dispersed hyphal elements. The different morphological fractions were quantified using image analysis. The apparent viscosity of the fermentation broth was significantly affected by the biomass concentration, the morphology, and also by pH. The chsB disruption strain had lower consistency index K values for all biomass concentrations investigated, which is a desirable trait for industrial Aspergillus fermentations. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 525–534, 2003.
Effect of nitrite and nitrate on in situ sulfide production in an activated sludge immobilized agar gel film as determined by use of microelectrodes
Authors: Okabe Satoshi , Santegoeds Cecilia M. , De Beer Dirk 
Published: January 2003

AbstractMicroelectrode, fluorescence in situ hybridization (FISH), and denaturing gradient gel electrophoresis (DGGE) analyses were used to investigate the effect of nitrite and nitrate on in situ sulfide production in an activated sludge immobilized agar gel film. Microelectrode measurements of O2, H2S, NO3−, NO2−, and pH revealed that the addition of NO2− and NO3− forced sulfate reduction zones deeper in the agar gel and significantly reduced the in situ sulfide production levels. The sulfate reduction zone was consequently separated from O2 and NO2− or NO3− respiration zones with increasing the concentrations of NO2− and NO3−. These NO2− and NO3− treatments had only a transient effect on sulfide production. The in situ sulfide production quickly recovered to the previous levels when NO2− and NO3− were removed. The PCR‐DGGE and FISH analyses revealed that 2‐day‐continuous addition of 500 μM NO3− did not change the metabolically active sulfate‐reducing bacterial (SRB) community. On the basis of these data, it could be concluded that the addition of NO2− and NO3− did not kill SRB, but induced the interspecies competition for common carbon source (i.e., acetate) between nitrate‐reducing heterotrophic bacteria and SRB and enhanced the oxidation of the produced sulfide, which were main possible causes of the suppression of in situ sulfide production in the agar gel. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 570–577, 2003.
Alphavirus cDNA‐based expression vectors: Effects of RNA transcription and nuclear export
Authors: Boorsma Marco , Saudan Philippe , Pfruender Holger , Bailey James E. , Schlesinger Sondra , Renner Wolfgang A. , Bachmann Marlin F. 
Published: January 2003

AbstractThe construction of layered DNA–RNA replicons has facilitated and expanded the use of alphavirus vectors to vaccine development, construction of packaging cell lines and long‐term heterologous gene expression. In these vector systems, the alphavirus replicon is under the control of a strong RNA polymerase II promoter and replicon RNA is transcribed from DNA before transport to the cytoplasm. Efficient RNA amplification catalyzed by the viral replicase results in high levels of mRNA and the recombinant protein. Recently, we developed a temperature‐regulated Sindbis replicon‐based DNA expression system characterized by a linear increase of expression upon decrease of the temperature from 37°C to 29°C. Modifications known to affect transcription and nuclear export of RNA led to a 5‐fold increase in expression in BHK cells and up to over 80‐fold increase in CHO cells and BF fibroblasts in transient transfection experiments. Furthermore, reducing cell proliferation resulted in a further 2‐ to 3‐fold higher expression. While increased expression per cell was responsible for some of the enhanced production, it was primarily the number of expressing cells that made the difference in most cell lines. Further experiments indicated that a threshold amount of replicon RNA had to reach the cytoplasm in order for replication to occur. Thus, alterations that improve transcription, nuclear export and stability of the RNA had a significant impact on protein production in the pCytTS expression system and probably in other layered DNA‐based viral vectors. Furthermore the results indicate that RNA replication is differentially regulated in DNA layered RNA replicons versus viral infection. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 553–562, 2003.
DNA purification by triple‐helix affinity precipitation
Authors: Costioli Matteo D. , Fisch Igor , Garret‐Flaudy Frédéric , Hilbrig Frank , Freitag Ruth 
Published: January 2003

AbstractRecent advances in DNA‐based medicine (gene therapy, genetic vaccination) have intensified the necessity for pharmaceutical‐grade plasmid DNA purification at comparatively large scales. In this contribution triple‐helix affinity precipitation is introduced for this purpose. A short, single‐stranded oligonucleotide sequence (namely (CTT)7), which is capable of recognizing a complementary sequence in the double‐stranded target (plasmid) DNA, is linked to a thermoresponsive N‐isopropylacrylamide oligomer to form a so‐called affinity macroligand (AML). At 4°C, i.e., below its critical solution temperature, the AML binds specifically to the target molecule in solution; by raising the temperature to 40°C, i.e., beyond the critical solution temperature of the AML, the complex can be precipitated quantitatively. After redissolution of the complex at lower temperature, the target DNA can be released by a pH shift to slightly alkaline conditions (pH 9.0). Yields of highly pure (plasmid) DNA were routinely between 70% and 90%. Non‐specific co‐ precipitation of either the target molecule by the non‐activated AML precursor or of contaminants by the AML were below 7% and presumably due to physical entrapment of these molecules in the wet precipitate. Ligand efficiencies were at least 1 order of magnitude higher than in triple‐helix affinity chromatography. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 535–545, 2003.
Microfluidic peroxidase biochip for polyphenol synthesis
Authors: Srinivasan Aravind , Wu Xiaoqiu , Lee Moo‐Yeal , Dordick Jonathan S. 
Published: January 2003

AbstractAn enzyme‐containing microfluidic biochip has been developed for the oxidative polymerization of phenols. The biochip consists of a simple T‐junction with two feed reservoirs 20 mm apart and a microreaction channel 30 mm long. The channel is 15 μm deep and 200 μm wide at the center, giving a reaction volume of 90 nL. The biochip was fabricated using conventional photolithographic methods on a glass substrate etched using a HF‐based solution. Fluid transport was enabled using electroosmotic flow. Soybean peroxidase was used as the phenol oxidizing catalyst, and in the presence of p‐cresol and H2O2, essentially complete conversion of the H2O2 (the limiting substrate) occurred in the microchannel at a flow rate of ca. 290 nL/min. Thus, peroxidase was found to be intrinsically active even upon dramatic scale‐down as achieved in microfluidic reactors. These results were extended to a series of phenols, thereby demonstrating that the microfluidic peroxidase reactor may have application in high‐throughput screening of phenolic polymerization reactions for use in phenolic resin synthesis. Finally, rapid growth of poly(p‐cresol) on the walls of the microreaction channel could be performed in the presence of higher H2O2 concentrations. This finding suggests that solution‐phase peroxidase catalysis can be used in the controlled deposition of polymers on the walls of microreactors. © 2003 Wiley Periodicals. Biotechnol Bioeng 81: 563–569, 2003.
Uptake of macrominerals and trace elements by the cyanobacterium Spirulina platensis (Arthrospira platensis PCC 8005) under photoautotrophic conditions: Culture medium optimization
Authors: Cogne Guillaume , Lehmann Bernd , Dussap Claude‐Gilles , Gros Jean‐Bernard 
Published: January 2003

AbstractUptake rates of macrominerals and trace elements were characterized in batch and continuous cultures of Spirulina platensis under photoautotropic conditions. The values of yield coefficients were determined using inductively coupled plasma emission spectroscopy (ICP‐ES). Further simplifications of culture medium proved possible, mainly in the trace element solutions; concentrations of some elements were lowered and trace elements B, Mo, V, Cr, Ni, Co, W, and Ti were removed. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 588–593, 2003.
Composite surface for blocking bacterial adsorption on protein biochips
Authors: Huang Tom T. , Sturgis Jennifer , Gomez Rafael , Geng Tao , Bashir Rashid , Bhunia Arun K. , Robinson J. Paul , Ladisch Michael R. 
Published: January 2003

AbstractThe design and fabrication of protein biochips requires characterization of blocking agents that minimize nonspecific binding of proteins or organisms. Nonspecific adsorption of Escherichia coli, Listeria innocua, and Listeria monocytogenes is prevented by bovine serum albumin (BSA) or biotinylated BSA adsorbed on SiO2 surfaces of a biochip that had been modified with a C18 coating. Biotinylated BSA forms a protein‐based surface that in turn binds streptavidin. Because streptavidin has multiple binding sites for biotin, it in turn anchors other biotinylated proteins, including antibodies. Hence, biotinylated BSA simultaneously serves as a blocking agent and a foundation for binding an interfacing protein, avidin or streptavidin, which in turns anchors biotinylated antibody. In our case, the antibody is C11E9, an IgG‐type antibody that binds Listeria spp. Nonspecific adsorption of another bacterium, Escherichia coli, is also minimized due to the blocking action of the BSA. The blocking characteristics of BSA adsorbed on C18‐derivatized SiO2 surfaces for construction of a protein biochip for electronic detection of pathogenic organisms is investigated. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 618–624, 2003.