bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel escherichia coli strain allows efficient recombinant protein production using lactose as inducer
Authors: Menzella Hugo G. , Ceccarelli Eduardo A. , Gramajo Hugo C. 
Published: April 2003

AbstractAn important characteristic of promoters used in recombinant protein production in Escherichi coli is their inducibility in a simple and cost‐effective manner. The IPTG inducible promoters lac, tac, and trc are powerful and widely used for basic research. However, the use of IPTG in large‐scale production is undesirable due to its high cost and toxicity. The promoters mentioned above can also be induced by the addition of lactose, which has the double role of inducer and carbon and energy source. Nevertheless, the use of this sugar in industrial processes has several drawbacks, which result in low volumetric yields and difficulties in process control. We have genetically engineered a BL21 strain to allow the efficient use of lactose as inducer in fed‐batch cultures. Two modifications were introduced, the exchange of the wild‐type lac operator by a constitutive one (lacOc) and the replacement of the gal alleles to recover the Gal+ phenotype. The constitutive expression of the lac operon overcame the negative effects that the Lac nongenetic heterogeneity of wild‐type E. coli introduces when lactose is used as inducer. The gal+ genotype allowed the complete use of the lactose as carbon and energy source. The relevance of these two modifications in the efficient utilization of lactose as inducer was demonstrated in fed‐batch cultures of the novel recombinant strain MP101 harboring expression vectors containing the calf prochymosin gene or the pccB gene, which encodes for the carboxyltransferase component of a propionyl‐CoA carboxylase complex from Streptomyces coelicolor. Similar levels of recombinant protein production (up to 16 g/L) were obtained by using either lactose or IPTG as inducers, which confirmed the success of the genetics modifications introduced. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 809–817, 2003.
Control of xylose consumption by xylose transport in recombinant Saccharomyces cerevisiae
Authors: Gárdonyi Márk , Jeppsson Marie , Lidén Gunnar , Gorwa‐Grauslund Marie F. , Hahn‐Hägerdal Bärbel 
Published: April 2003

AbstractSaccharomyces cerevisiae TMB3001 has previously been engineered to utilize xylose by integrating the genes coding for xylose reductase (XR) and xylitol dehydrogenase (XDH) and overexpressing the native xylulokinase (XK) gene. The resulting strain is able to metabolize xylose, but its xylose utilization rate is low compared to that of natural xylose utilizing yeasts, like Pichia stipitis or Candida shehatae. One difference between S. cerevisiae and the latter species is that these possess specific xylose transporters, while S. cerevisiae takes up xylose via the high‐affinity hexose transporters. For this reason, in part, it has been suggested that xylose transport in S. cerevisiae may limit the xylose utilization.We investigated the control exercised by the transport over the specific xylose utilization rate in two recombinant S. cerevisiae strains, one with low XR activity, TMB3001, and one with high XR activity, TMB3260. The strains were grown in aerobic sugar‐limited chemostat and the specific xylose uptake rate was modulated by changing the xylose concentration in the feed, which allowed determination of the flux response coefficients. Separate measurements of xylose transport kinetics allowed determination of the elasticity coefficients of transport with respect to extracellular xylose concentration. The flux control coefficient, C, for the xylose transport was calculated from the response and elasticity coefficients. The value of C for both strains was found to be < 0.1 at extracellular xylose concentrations > 7.5 g L−1. However, for strain TMB3260 the flux control coefficient was higher than 0.5 at xylose concentrations < 0.6 g L−1, while C stayed below 0.2 for strain TMB3001 irrespective of xylose concentration. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 818–824, 2003.
New approach to regioselective synthesis: Using proteins in vitro as guidance—regioselective reduction of steroids with guidance from bovine serum albumin
Authors: Liu Xiao‐Chuan , Kayser Lauren 
Published: April 2003

AbstractA novel approach for regioselective synthesis is described. The approach uses the unique binding properties of protein as a guide to achieve regioselectivity. Specifically, steroids, e.g., 4‐androstene‐3,17‐dione, were reduced selectively at carbon 17 using bovine serum albumin (BSA) as a regio auxlliary. The approach has resulted in a high yield (ca. 91%) in an environmental friendly aqueous medium. Both 1H NMR and 13C NMR data show that the BSA‐assisted reduction of the steroid render the reaction regioselective compared to the control reaction. Various control reactions were performed to verify that the unique binding of BSA to steroids was the origin of regioselectivity. After one cycle of the reduction reaction, BSA was reconditioned such that it could be reused five or more times. This novel approach could be used to develop practical and “green” methods for regioselective synthesis. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 858–863, 2003.
Production of mannitol and lactic acid by fermentation with Lactobacillus intermedius NRRL B‐3693
Authors: Saha Badal C. , Nakamura Lawrence K. 
Published: April 2003

AbstractLactobacillus intermedius B‐3693 was selected as a good producer of mannitol from fructose after screening 72 bacterial strains. The bacterium produced mannitol, lactic acid, and acetic acid from fructose in pH‐controlled batch fermentation. Typical yields of mannitol, lactic acid, and acetic acid from 250 g/L fructose were 0.70, 0.16, and 0.12 g, respectively per g of fructose. The fermentation time was greatly dependent on fructose concentration but the product yields were not dependent on fructose level. Fed‐batch fermentation decreased the time of maximum mannitol production from fructose (300 g/L) from 136 to 92 h. One‐third of fructose could be replaced with glucose, maltose, galactose, mannose, raffinose, or starch with glucoamylase (simultaneous saccharification and fermentation), and two‐thirds of fructose could be replaced with sucrose. L. intermedius B‐3693 did not co‐utilize lactose, cellobiose, glycerol, or xylose with fructose. It produced lactic acid and ethanol but no acetic acid from glucose. The bacterium produced 21.3 ± 0.6 g lactic acid, 10.5 ± 0.3 g acetic acid, and 4.7 ± 0.0 g ethanol per L of fermentation broth from dilute acid (15% solids, 0.5% H2SO4, 121°C, 1 h) pretreated enzyme (cellulase, β‐glucosidase) saccharified corn fiber hydrolyzate. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 864–871, 2003.
In vitro model of “wound healing” analyzed by laser scanning cytometry: Accelerated healing of epithelial cell monolayers in the presence of hyaluronate
Authors: Haider Asifa S. , Grabarek Jerzy , Eng Ben , Pedraza Paulina , Ferreri Nicholas R. , Balazs Endre A. , Darzynkiewicz Zbigniew 
Published: April 2003

AbstractBackgroundIn vitro models of “wound healing” rely on analysis of confluent cell cultures that are mechanically wounded, e.g., by scratching the cell monolayer. Damage and removal of cells during wounding provides mitogenic signals to the adjacent cells and induces their migration to close the wound. The progress of healing is generally estimated by microscopy or time‐lapse cinematography by assessing cell proliferation and/or migration that leads to the wound closure.MethodsThe aim of the present study was to adapt laser scanning cytometry (LSC) to measure cellular changes related to damage and recovery of a monolayer of primary epithelial cells from rat kidneys growing with and without hyaluronate (∼6 × 106 average molecular weight). Because x–y coordinates of the cell position on the slide were recorded by LSC, the apoptotic and proliferative changes in individual cells induced by wounding and wound closure could be correlated, by multiparameter analysis, with the cell location with respect to the wound.ResultsThe initial change, observed as soon as 4 h after scratching and seen among the cells at the wound edge, was the appearance of apoptotic cells, characterized by cell shrinkage, typically condensed chromatin, and activation of caspases, the latter detected by binding of fluorochrome‐labeled inhibitor of caspases. Their frequency was reduced to up to sixfold in the presence of hyaluronate. Cell proliferation, measured by frequency of cells incorporating bromodeoxyuridine, also reflected by percentage of cells in S, G2, and mitosis, was higher in proximity of the wound but was not significantly affected by hyaluronate. However, the monolayer gap closure was accelerated in the presence of hyaluronate.ConclusionsBy offering the means to measure apoptosis and proliferation in relation to the cell position (distance) with respect to the wound in cell monolayer and to relocate them for visual inspection, LSC is uniquely suited to quantitatively analyze in vitro the process of wound healing. Hyaluronate, the ubiquitous component of intercellular matrix, preparations of which are being used in the clinic to suppress inflammatory reactions in tissues and promote healing, accelerated the healing process by protecting cells from apoptosis and stimulating cell migration to close the gap in the cell monolayer. Cytometry Part A 53A:1–8, 2003. © 2003 Wiley‐Liss, Inc.
Quantitative fluorescence of 5‐FU–treated fetal rat limbs using confocal laser scanning microscopy and Lysotracker Red
Authors: Price Owen T. , Lau Christopher , Zucker Robert M. 
Published: April 2003

AbstractBackgroundLysoTracker Red (LT) is a paraformaldehyde fixable probe that concentrates into acidic compartments of cells and tissues. After cell death, a high level of lysosomal activity (acidic enzyme) is expressed in tissues resulting from phagocytosis of apoptotic bodies by neighboring cells. LT was shown previously to be an indicator of cell death in a manner similar to other standard assays (Annexin, terminal dUTP nick end labeling, Nile blue sulfate, neutral red, and acridine orange).MethodsLT fluorescence in fetal rat hindlimbs at gestational day 14 was measured 8 h after administration of the teratogen, 5‐fluorouracil (5‐FU), with the use of confocal laser scanning microscopy (CLSM). Four dose levels of 5‐FU (0, 20, 30, and 40 mg/kg) were studied. The preparation technique involved staining with LT, paraformaldehyde fixation, methanol dehydration, and clearance with benzyl alcohol and benzyl benzoate. After this treatment, the limb was nearly transparent and ready for CLSM analysis.ResultsLT staining was observed in specific regions undergoing apoptosis in normal (control) hindlimbs. After 5‐FU treatment, highly fluorescent regions appeared in the progress zone (PZ) of the limb. A dose‐dependent response to 5‐FU treatment was observed. Compared with controls, hindlimbs treated with 20, 30, and 40 mg/kg of 5‐FU exhibited more fluorescence within the highly proliferative PZ. These results showed a dose–response relation between 5‐FU exposure and LT uptake.ConclusionsWe found that three‐dimensional volumetric regions indicating a high level of fluorescence in the embryonic limb bud can be quantified with three different computer analysis programs. The combination of a sample preparation procedure that clears tissue, a CLSM technique that addresses the equipment variables, and an application of statistical population analysis procedures enabled the visualization and quantification of fluorescence in entire fetal rat hindlimbs that were approximately 500 μm in thickness. Cytometry Part A 53A:9–21, 2003. Published 2003 Wiley‐Liss, Inc.
Optimal preparation of rhesus macaque blood for cytokine flow cytometric analysis
Authors: Nomura Laurel E. , deHaro Eileen D. , Martin Louis N. , Maecker Holden T. 
Published: April 2003

AbstractBackgroundThe rhesus macaque is a common substitute for human subjects in many disease models, including simian immunodeficiency virus, the non‐human primate equivalent of the human immunodeficiency virus. Monoclonal antibodies and fluorochromes optimized for use in macaques were included in samples examined for immune responses with the use of intracellular cytokine flow cytometry (CFC).MethodsSample preparation was optimized based on the following comparisons: activation of peripheral blood mononuclear cells (PBMCs) versus whole blood; separation of PBMCs using BD Vacutainer cell preparation tubes versus Ficoll; and activation of samples on the day they were collected versus holding samples overnight.ResultsWhen activated with the simian immunodeficiency virus type mac239 and Gag peptide mix or with the superantigen Staphylococcal enterotoxin B, separated PBMCs produced greater CD4 and CD8 fluorescence intensities and a larger percentage of CD69+ cytokine‐positive cells than did whole blood samples. PBMCs separated by cell preparation tubes produced absolute T‐lymphocyte counts equivalent to that with Ficoll separation, and CFC results with both methods were similar. When subjected to overnight shipping conditions, whole blood and PBMCs sometimes showed a reduction in mean fluorescence intensity and percentage of CD69+ cytokine‐positive T lymphocytes.ConclusionsDue to this reduction in responses, it is preferable to activate samples on the day of blood collection. Samples can be surface stained and frozen in BD FACS Lysing Solution, to be thawed at a later date; this preserves their ability to display a cytokine response. Thus optimal CFC results are achieved by separating macaque PBMCs from whole blood, activating samples on day of collection, and, if necessary, freezing samples after surface staining for future analysis. Cytometry Part A 53A:28–38, 2003. © 2003 Wiley‐Liss, Inc.
Genetic linkage maps of the West African clawed frog Xenopus tropicalis
Authors: Kochan Kelli J. , Wright David A. , Schroeder Lisa J. , Shen Jianjun , Morizot Donald C. 
Published: April 2003

AbstractThe original article to which this Erratum refers was published in Developmental Dynamics 226:99–102 Developmental Dynamics(2003) 226(1) 99–102
Malleal processus brevis is dispensable for normal hearing in mice
Authors: Zhang Zunyi , Zhang Xiaoyun , Avniel Wilma A. , Song Yiqiang , Jones Sherri M. , Jones Timothy A. , Fermin Cesar , Chen Yiping 
Published: April 2003

AbstractThe mammalian middle ear cavity contains a chain of three ossicles (the malleus, incus, and stapes), which develop from the mesenchyme of the first two branchial arches. Mice deficient in the Msx1 homeobox gene exhibit craniofacial abnormalities, including the absence of the malleal processus brevis that is normally attached to the upper part of the tympanic membrane. Here, we show that the expression of Msx1 and Msx2 overlaps in the malleal primordium during early embryonic development. A functional redundancy of Msx1 and Msx2 in the development of the middle ear is suggested by the stronger hypomorphism in the malleus of Msx1‐/‐/Msx2‐/‐ embryos, including the absence of the malleal manubrium and the malleal processus brevis. The expression of Bmp4, a known downstream target of Msx1 in several developing craniofacial organs, was down‐regulated in the malleal primordium, particularly in the region of the developing malleal manubrium, of Msx1 and Msx1‐/‐/Msx2‐/‐ embryos. Msx genes, thus, appear to act in a cell autonomous manner, possibly by regulating Bmp4 expression, in the formation of the malleus. Transgenic rescue of the cleft palate of Msx1‐/‐ mice overcame the neonatal lethality and allowed Msx1‐/‐ mice to grow into adulthood but retain the phenotype of the absence of the malleal processus brevis. The availability of this animal model for the first time allowed us to measure auditory evoked potentials to assess the functional significance of the malleal processus brevis. The results demonstrated unimpaired auditory function in Msx1‐/‐ mice. In addition, mutant mice appeared normal in balance behavior and in the vestibular evoked potential screening test. These results indicate that the malleal processus brevis is not necessary for sound transmission and seems dispensable for normal hearing and balance in mammals. Developmental Dynamics 227:69–77, 2003 © 2003 Wiley‐Liss, Inc.
Differential expression of the two Drosophila fos/kayak transcripts during oogenesis and embryogenesis
Authors: Souid Sami , Yanicostas Constantin 
Published: April 2003

AbstractThe Dfos/kayak gene encodes a bZIP protein, DFos, required in a large variety of differentiation and morphogenetic processes throughout Drosophila development. The recent availability of an expressed sequence tag (EST) sequence led us to identify a novel kay mRNA encoding a deduced DFos isoform showing a specific NH2‐terminal region. To gain further insight into the function and the regulation of this gene, we have investigated the expression pattern of the two kay mRNA isoforms, kay‐RA and kay‐RB, during oogenesis and embryogenesis by whole‐mount in situ hybridization. Results show that, although the two kay RNA isoforms display fully distinct patterns of transcription during oogenesis, they show partially overlapping expression profiles in embryos. These data reveal a previously unsuspected level of complexity in the regulation of the expression of the kay gene. In addition, they suggest a possible requirement for this gene in the invagination processes during early gastrula stages. Developmental Dynamics, 227:150–154, 2003. © 2003 Wiley‐Liss, Inc.
Genomic organization and promoter and transcription regulatory regions for the expression in the anterior brain (sensory vesicle) of Hroth, the otx homologue of the ascidian, Halocynthia roretzi
Authors: Oda‐Ishii Izumi , Saiga Hidetoshi 
Published: April 2003

AbstractOtx (otd in Drosophila) is a well‐conserved homeobox gene throughout animal phylogeny and commonly expressed in the anterior part of the embryo. In embryos of the ascidian Halocynthia roretzi, Hroth, the otx homologue in this species, is expressed in the endoderm and the sensory vesicle, the anterior part of the larval ascidian central nervous system (CNS), which has been thought to be homologous to vertebrate forebrain and midbrain. The developmental expression pattern of Hroth is very similar to that of vertebrate counterparts, which leads to a possibility that a similar mechanism may exist in the patterning of the CNS between ascidians and vertebrates. To better understand the mechanism, we decided to undertake analysis of the transcriptional regulatory regions of Hroth. We isolated and determined the nucleotide sequence of the 11.4‐kbp region upstream of the translation start site of Hroth. We found that Hroth transcripts are modified likely with spliced leader RNA; therefore, we could not determine the transcription start site. However, first, we identified three introns that are unknown with vertebrate otx genes. Second, we found two regions that are capable of functioning as a promoter through deletion analysis, one of which appeared to be an endogenous promoter of Hroth. We analyzed the 5′ upstream region 5402‐1473bp, the region between 1473 and 5402 base pairs upstream from the translation start site of Hroth, including the putative endogenous promoter. This region was capable of driving Hroth expression in the sensory vesicle lineage cells as well as some other lineages at the early tail bud stage. Deletion analysis of this region suggested that three regions, 1659‐1650bp, 1628‐1613bp, and 1542‐1473bp are responsible for regulating Hroth expression in the sensory vesicle cells at the tail bud stage. Among these regions, no apparent sequence conservation was observed. The present study has revealed a complex organization of transcription regulatory regions for the ascidian otx. Developmental Dynamics 227:104–113, 2003. © 2003 Wiley‐Liss, Inc.
Pricing continuously sampled Asian options with perturbation method
Authors: Zhang Jin E. 
Published: April 2003

AbstractThis article explores the price of continuously sampled Asian options. For geometric Asian options, we
present pricing formulas for both backward‐starting and forward‐starting cases. For arithmetic
Asian options, we demonstrate that the governing partial differential equation (PDE) cannot be
transformed into a heat equation with constant coefficients; therefore, these options do not have a
closed‐form solution of the Black–Scholes type, that is, the solution is not given in terms of the
cumulative normal distribution function. We then solve the PDE with a perturbation method and obtain an
analytical solution in a series form. Numerical results show that as compared with Zhang's (2001) highly accurate numerical results, the series converges very quickly and gives a
good approximate value that is more accurate than any other approximate method in the literature, at least for
the options tested in this article. Graphical results determine that the solution converges globally very
quickly especially near the origin, which is the area in which most of the traded Asian options fall. ©
2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:535–560, 2003
The effect of liquidity constraints on futures hedging
Authors: Lien Donald 
Published: April 2003

AbstractThis article assumes that because of liquidity constraints, a hedge program will be terminated if the
cumulative loss from a futures position exceeds a certain threshold. The constraint leads to a smaller futures
position. If the hedger has a quadratic utility function, then the optimal futures position is constant regardless
of the parameter values and increases as the spot position or the conventional hedge ratio increases. When the
capital allocation is small, the hedger tends to ignore this restriction and chooses a larger position.
Consequently, the optimal position may decrease as the capital allocation increases. For a moderate capital
allocation, the optimal position increases with an increasing capital allocation. Similar properties are
established for exponential utility functions. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:603–613,
2003
Operational reviews and auditing ERP
Authors: Goldberg Stephen R. , Godwin Joseph H. 
Published: April 2003

AbstractReider, Rob. 2002. Operational Review: Maximum Results at Efficient Costs, 3rd edition
(New York: John Wiley & Sons).Musaji, Yusufali F. 2002. Integrated Auditing of ERP Systems (New York: John Wiley &
Sons).