bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasmid DNA Purification by Selective Calcium Silicate Adsorption of Closely Related Impurities
Authors: Winters Michael A. , Richter Jesse D. , Sagar Sangeetha L. , Lee Ann L. , Lander Russel J. 
Published: April 2003

AbstractThe selective adsorption of supercoiled plasmid, open‐circular plasmid, and genomic DNA to gyrolite, a compound from the class of crystalline calcium silicate hydrates, is investigated and exploited for purification purposes. Genomic DNA and open‐circular plasmid bind to gyrolite adsorbents with greater affinity than the more conformationally constrained supercoiled plasmid. As such, the gyrolite adsorbents are an economical and scaleable alternative to chromatographic purification for the removal of DNA impurities from solutions containing supercoiled plasmid. The advantage of gyrolite adsorbents is their lower unit price and ability to selectively adsorb DNA impurities without binding supercoiled plasmid under certain conditions. The effects of ionic strength, temperature, chelating agent, divalent cation, and lyotropic salts on adsorption of highly purified plasmid are studied to understand the forces that bind DNA to gyrolite, a structure with hydrophilic and hydrophobic characteristics. The results indicate that DNA binding is governed by hydrogen bonding, electrostatic bridging with divalent cations, shielding of electrostatic repulsion, hydrophobic adsorption, and disruption of integral surface water layer on gyrolite. On the basis of results from a range of Hofmeister series salts, strongly hydrated anions may enhance DNA adsorption by promoting hydrophobic interactions between DNA and gyrolite. Conversely, the very weakly hydrated chaotrope I− may enhance adsorption by strongly associating with hydrophobic siloxanes of gyrolite, thereby disrupting an integral water layer, which competes for hydrogen bonding sites.
Oil and Air Dispersion in a Simulated Fermentation Broth as a Function of Mycelial Morphology
Authors: Lucatero Savidra , Patricia Larralde‐Corona Claudia , Corkidi Gabriel , Galindo Enrique 
Published: April 2003

AbstractThe culture conditions of a multiphase fermentation involving morphologically complex mycelia were simulated in order to investigate the influence of mycelial morphology ( Trichoderma harzianum) on castor oil and air dispersion. Measurements of oil drops and air bubbles were obtained using an image analysis system coupled to a mixing tank. Complex interactions of the phases involved could be clearly observed. The Sauter diameter and the size distributions of drops and bubbles were affected by the morphological type of biomass (pellets or dispersed mycelia) added to the system. Larger oil drop sizes were obtained with dispersed mycelia than with pellets, as a result of the high apparent viscosity of the broth, which caused a drop in the power drawn, reducing oil drop break‐up. Unexpectedly, bubble sizes observed with dispersed mycelia were smaller than with pellets, a phenomenon which can be explained by the segregation occurring at high biomass concentrations with the dispersed mycelia. Very complex oil drops were produced, containing air bubbles and a high number of structures likely consisting of small water droplets. Bubble location was influenced by biomass morphology. The percentage (in volume) of oil‐trapped bubbles increased (from 32 to 80%) as dispersed mycelia concentration increased. A practically constant (32%) percentage of oil‐trapped bubbles was observed with pelleted morphology at all biomass concentrations. The results evidenced the high complexity of phases interactions and the importance of mycelial morphology in such processes.
Prediction of the Equilibrium Conversion for the Synthesis of Acyl Hexose through Lipase‐Catalyzed Condensation in Water‐Miscible Solvent in the Presence of Molecular Sieve
Authors: Zhang Xiaoming , Adachi Shuji , Watanabe Yoshiyuki , Kobayashi Takashi , Matsuno Ryuichi 
Published: April 2003

AbstractA method is proposed for predicting the equilibrium conversion for the synthesis of monoacyl hexose through the lipase‐catalyzed condensation of a fatty acid and a hexose in a water‐miscible solvent in the presence of a molecular sieve, based on the apparent reaction equilibrium constant, the adsorption isotherm of water on the molecular sieve, the solubility of hexose in the solvent, and the mass balance with respect of water. Validity of the model was examined for the syntheses of lauroyl mannose, lauroyl glucose, and myristoyl mannose in acetonitrile, 2‐methyl‐2‐propanol, or 2‐methyl‐2‐butanol with molecular sieves 3A 1/16 and 4A 1/16. The predicted conversions agreed well with the experimental values except for the case where a significant amount of diester was formed as the result of the addition of an excess amount of the molecular sieve to the solvent or the high molar ratio of the fatty acid to the hexose.
Low‐Glutamine Fed‐Batch Cultures of 293‐HEK Serum‐Free Suspension Cells for Adenovirus Production
Authors: Lee Yih Yean , Yap Miranda G. S. , Hu Wei‐Shou , Wong Kathy T. K. 
Published: April 2003

AbstractRecent developments in gene therapy using adenoviral (Ad) vectors have fueled renewed interest in the 293 human embryonic kidney cell line traditionally used to produce these vectors. Low‐glutamine fed‐batch cultures of serum‐free, suspension cells in a 5‐L bioreactor were conducted. Our aim was to tighten the control on glutamine metabolism and hence reduce ammonia and lactate accumulation. Online direct measurement of glutamine was effected via a continuous cell‐exclusion system that allows for aseptic, cell‐free sampling of the culture broth. A feedback control algorithm was used to maintain the glutamine concentration at a level as low as 0.1 mM with a concentrated glucose‐free feed medium. This was tested in two media: a commercial formulation (SFM II) and a chemically defined DMEM/F12 formulation. The fed‐batch and batch cultures were started at the same glucose concentration, and it was not controlled at any point in the fed‐batch cultures. In all cases, fed‐batch cultures with double the cell density and extended viable culture time compared to the batch cultures were achieved. An infection study on the high density fed‐batch culture using adenovirus‐green fluorescent protein (Ad‐GFP) construct was also done to ascertain the production capacity of the culture. Virus titers from the infected fed‐batch culture showed that there is an approximately 10‐fold improvement over a batch infection culture. The results have shown that the control of glutamine at low levels in cultures is sufficient to yield significant improvements in both cell densities and viral production. The applicability of this fed‐batch system to cultures in different media and also infected cultures suggests its potential for application to generic mammalian cell cultures.
Production and Characterization of Exopolysaccharides from an Enthomopathogenic Fungus Cordycepsmilitaris NG3
Authors: Kim Sang Woo , Xu Chun Ping , Hwang Hye Jin , Choi Jang Won , Kim Chan Woo , Yun Jong Won 
Published: April 2003

AbstractOptimization of the submerged culture conditions for the mycelial growth and production of exopolysaccharide (EPS) from a newly isolated Cordycepsspecies ( C. militarisNG3) was studied in flask cultures. The optimal temperature and initial pH for EPS production were 30 °C and 8.0, respectively. Sucrose (30 g/L) and corn steep powder (10 g/L) were the most suitable carbon and nitrogen source for both mycelial growth and EPS production. There was a distinguishable morphological changes in mycelium grown between organic and inorganic nitrogen sources. A smooth pellet growth with heavy hyphal thickness was observed in the medium containing organic nitrogen sources, whereas irregular pellets with less hairy region were formed in the medium containing inorganic nitrogen sources. More highly branched cells appearing in the medium of organic nitrogen sources seemed a favorable morphological form for both EPS production and mycelial growth. Under optimal culture conditions, the maximum concentrations of mycelial growth and EPS were 17.6 and 3.4 g/L in a 5‐L stirred‐tank fermenter. Four groups of EPSs (designated as Fr‐I, Fr‐II, Fr‐III, and Fr‐IV) were obtained from the culture filtrates by size exclusion chromatography (SEC), and their molecular characteristics were examined by a multiangle laser‐light scattering (MALLS) and refractive index (RI) detector system. The weight‐average molar masses of the Fr‐I, Fr‐II, Fr‐III, and Fr‐IV of EPS were determined to be 2.262 × 106, 3.348 × 105, 1.049 × 105, and 5.059 × 104 g/mol, respectively. All four EPSs showed very low polydispersity indices ranging from 1.00 to 1.18. The SEC/MALLS analysis revealed that the molecular shape of the Fr‐I was a rigid sphere suspected to be an aggregate of complex polysaccharides, the Fr‐II and Fr‐III were nearly globular in shape, and the Fr‐IV was an almost rodlike structure.
A Feasible Enzymatic Process for d‐Tagatose Production by an Immobilized Thermostable l‐Arabinose Isomerase in a Packed‐Bed Bioreactor
Authors: Kim Hye‐Jung , Ryu Se‐Ah , Kim Pil , Oh Deok‐Kun 
Published: April 2003

AbstractTo develop a feasible enzymatic process for d‐tagatose production, a thermostable l‐arabinose isomerase, Gali152, was immobilized in alginate, and the galactose isomerization reaction conditions were optimized. The pH and temperature for the maximal galactose isomerization reaction were pH 8.0 and 65 °C in the immobilized enzyme system and pH 7.5 and 60 °C in the free enzyme system. The presence of manganese ion enhanced galactose isomerization to tagatose in both the free and immobilized enzyme systems. The immobilized enzyme was more stable than the free enzyme at the same pH and temperature. Under stable conditions of pH 8.0 and 60 °C, the immobilized enzyme produced 58 g/L of tagatose from 100 g/L galactose in 90 h by batch reaction, whereas the free enzyme produced 37 g/L tagatose due to its lower stability. A packed‐bed bioreactor with immobilized Gali152 in alginate beads produced 50 g/L tagatose from 100 g/L galactose in 168 h, with a productivity of 13.3 (g of tagatose)/(L‐reactor·h) in continuous mode. The bioreactor produced 230 g/L tagatose from 500 g/L galactose in continuous recycling mode, with a productivity of 9.6 g/(L·h) and a conversion yield of 46%.
Use of Flow Cytometry To Monitor Infection and Recombinant Human α‐1,3/4 Fucosyltransferase Production in Baculovirus Infected Sf9 Cell Cultures
Authors: Deparis V. , Jestin A. , Marc A. , Goergen J. L. 
Published: April 2003

AbstractThis paper describes the setup and the use of a flow cytometric method for monitoring Sf9 insect cell infection by a recombinant baculovirus expressing the human α1,3/4 fucosyltransferase Fuc‐TIII. Using side scattered light coupled to green fluorescence detection after immunolabeling of the recombinant protein, this method made it possible to monitor baculovirus infection of Sf9 cells grown in batch cultures and infected at different cell densities and multiplicities of infection. The method was able to precisely assess the extent of infection of the insect cells from 60 h postinfection. In asynchronously infected Sf9 cell cultures, the two‐step infection process (primary and secondary infection) was well‐characterized using this technique. Finally, a reduced sensitivity to baculovirus infection was observed for cells infected at the end of the growth phase compared to the cells infected during exponential growth phase.
Evaluation of Retroviral Production Systems Using Quantitative Analysis
Authors: Kwon Young Jik , Peng Ching‐An 
Published: April 2003

AbstractBecause of the low titer of retroviral supernatant, it is necessary to develop and optimize large‐scale retroviral production systems. To quantitatively determine the effect of a given operating condition (e.g., temperature and serum content) on producer cells' retrovirus‐producing capacity, a mathematical model was used to analyze the static retroviral production system described by three processes: viral diffusion, decay, and generation. The analytical solutions of the defined model equations were fitted with experimental data to determine the specific retroviral production rate constant, which represents the competence of a retroviral production system. Two different retroviral production systems, inducible production of vesicular stomatitis virus G glycoprotein (VSV‐G) pseudotyped retrovirus from 293GPG/EGFP cells and constant production of ecotropic retrovirus from GP+E86/LNCX cells, were employed to demonstrate the feasibility of the engineering analysis. Our results indicated that the time‐variant specific retroviral production rate of 293GPG/EGFP cells reached its maximum value of 5.7 × 10−3 CFU/cm2·h·cell, and the constant specific retroviral production rate of GP+E86/LNCX cells was 1.49 × 10−2 CFU/cm2·h·cell for the whole period of production. Furthermore, the effects of serum concentration and temperature on the ecotropic retroviral production system were examined separately. Our results suggest that producing ecotropic retroviruses with 10% fetal bovine serum at 37 °C is the optimal operating conditions for the long‐term production system used here.
Lipase Catalysis in Ionic Liquids and Supercritical Carbon Dioxide at 150 °C
Authors: Lozano Pedro , de Diego Teresa , Carrié Daniel , Vaultier Michel , Iborra José L. 
Published: April 2003

AbstractFree and immobilized Candida antarctica lipase B dispersed in ionic liquids (1‐ethyl‐3‐methylimidazolium bistriflimide and 1‐buthyl‐3‐methylimidazolium bistriflimide) were used as catalyst for the continuous kinetic resolution of rac‐1‐phenylethanol in supercritical carbon dioxide at 120 and 150 °C and 10 MPa. Excellent activity, stability and enantioselectivity levels were recorded in continuous operation.
Batch Kinetics of Pseudomonas sp. Growth on Benzene. Modeling of Product and Substrate Inhibitions
Authors: Monero Alessandra , Lanza Luca , Zilli Mario , Sene Luciane , Converti Attilio 
Published: April 2003

AbstractBatch tests of benzene degradation were performed in liquid phase at 30 °C, pH 6.8 ± 0.2, and 200 rpm in two 3‐L stirred tank bioreactors, using the benzene‐degrading bacterium Pseudomonas sp. NCIMB 9688. A relatively high starting biomass level (220–270 mgX/L) and starting benzene concentration ranging from 20 to 200 mgS/L were selected as conditions to investigate possible inhibition phenomena. Volumetric as well as specific rates of biomass formation and substrate consumption were calculated from experimental data of both growth and benzene degradation and used to propose and check a new overall kinetic model for cell growth simultaneously accounting for both product and substrate inhibitions. The results of the present study evidenced the occurrence of a competitive‐type product inhibition due to 2‐hydroxymuconic semialdehyde ( KiP′ = 0.902 mgS/L), which was stronger than the uncompetitive‐type inhibition exerted by substrate ( KiS = 7.69 mgS/L).
Curriculum Evaluation and Assessment of Multicultural Genetic Counselor Education
Authors: Wang Vivian Ota 
Published: April 2003

AbstractMulticultural competence in genetic counseling integrates racial‐cultural knowledge, awareness, and skills into clinical interventions and research practices. Researchers and educators often cite racial‐cultural factors as obstacles for visible racial‐cultural people seeking help. However, the professional's unfamiliarity of how his or her own racial‐cultural group affiliations are influenced by the history of discrimination and oppression coupled with their lack of self‐understanding of racial‐cultural issues for him‐ or herself has also limited the effectiveness of genetic counseling. The purpose of this study is to evaluate the effectiveness of the Handbook of Cross‐Cultural Genetic Counseling, a multicultural curriculum developed for genetic counselor education for increasing multicultural counseling competence. The multicultural curriculum was evaluated for its effectiveness of increasing multicultural counseling competence using a nonequivalent control group design. A participant's multicultural counseling competence was hypothesized to increase after being taught the curriculum. The curriculum was effective for increasing multicultural counseling competence. Additionally, achieved multicultural counseling competence was not influenced by when the curriculum was taught. Trend analyses measuring the longitudinal impact of the curriculum on multicultural competence were significant. Implications of the results are discussed.
Effects of Enforcement of Youth Access Laws on Smoking Prevalence
Authors: Jason Leonard A. , Berk Marjorie , Schnopp-Wyatt Daniel L. , Talbot Bruce 
Published: April 2003

AbstractSmoking is the primary preventable cause of death, and yet 3,000 adolescents become smokers each day. Most adult smokers begin this deadly habit when they are under the age of 18, which is the minimum legal age for the purchase of cigarettes. The majority of adolescent smokers are able to purchase cigarettes even though laws prohibit the sale of cigarettes to minors. In the late 1980s, Woodridge, IL, became one of the first towns in the nation to demonstrate a significant reduction in the ability of youth to purchase cigarettes. Almost 2 years after passage of this legislation, the percentage of regular smokers among 7th‐ and 8th‐grade students had been reduced from 16 to 5%. Seven‐year follow‐up data in a sample of high school youths indicate that youths living in communities with regular enforcement had significantly less smoking than those living in communities without regular enforcement. In particular, rates of regular smoking were 8.1% in communities with regular enforcement versus 15.5% in communities without regular enforcement. It is possible that adolescents who had restricted access to tobacco products were less likely to become regular smokers. These findings have important public health implications, particularly in light of recent federal legislation mandating that all states develop programs to reduce access of youth to tobacco products.
Preconception Genetic Counseling: Three Years of Experience at a Community‐Based Health Center
Authors: Lemke Amy A. , Dayal Sheela , Geibel Leslie J. 
Published: April 2003

AbstractIn the United States, access to genetic education and services is not equally available to all segments of the population, especially to women of minority backgrounds and low incomes. In response to this issue, the Preconception Genetic Health Education Program (PGHEP) was implemented in September of 1993 at the Woodlawn Maternal and Child Health Center in south side Chicago. The goal of this program is to provide access to genetic services to a previously underserved population. Women attending the family planning clinics are offered free, confidential preconception genetic screening and counseling on‐site. As of January 1, 1997, 1300 women have participated in the program. The development and implementation of the PGHEP, client self‐reports of family histories and beliefs, and implications for future delivery of genetic services are discussed.
Secondary traumatic stress effects of working with survivors of criminal victimization
Authors: Salston MaryDale , Figley Charles R. 
Published: April 2003

AbstractThis paper focuses on the consequences for providers of working with survivors of traumatic events, particularly criminal victimization. The paper reviews the relevant research and treatment literature associated with secondary traumatic stress (STS) and related variables (burnout, compassion fatigue, vicarious trauma, and countertransference). The latter part of the paper identifies the most important mitigating factors in the development of STS. These include good training specific to trauma work, a personal history of trauma, and the interpersonal resources of the worker. Implications for treatment, prevention, and research are discussed.
Cloning and Heterologous Expression of a β-
d
-Mannosidase (EC 3.2.1.25)-Encoding Gene from
Thermobifida fusca
TM51
Authors: Béki Emese , Nagy István , Vanderleyden Jos , Jäger Szilvia , Kiss László , Fülöp László , Hornok László , Kukolya József 
Published: April 2003

ABSTRACT

Thermobifida fusca
TM51, a thermophilic actinomycete isolated from composted horse manure, was found to produce a number of lignocellulose-degrading hydrolases, including endoglucanases, exoglucanases, endoxylanases, β-xylosidases, endomannanases, and β-mannosidases, when grown on cellulose or hemicellulose as carbon sources. β-Mannosidases (EC 3.2.1.25), although contributing to the hydrolysis of hemicellulose fractions, such as galacto-mannans, constitute a lesser-known group of the lytic enzyme systems due to their low representation in the proteins secreted by hemicellulolytic microorganisms. An expression library of
T. fusca
, prepared in
Streptomyces lividans
TK24, was screened for β-mannosidase activity to clone genes coding for mannosidases. One positive clone was identified, and a β-mannosidase-encoding gene (
manB
) was isolated. Sequence analysis of the deduced amino acid sequence of the putative ManB protein revealed substantial similarity to known mannosidases in family 2 of the glycosyl hydrolase enzymes. The calculated molecular mass of the predicted protein was 94 kDa, with an estimated pI of 4.87.
S. lividans
was used as heterologous expression host for the putative β-mannosidase gene of
T. fusca
. The purified gene product obtained from the culture filtrate of
S. lividans
was then subjected to more-detailed biochemical analysis. Temperature and pH optima of the recombinant enzyme were 53°C and 7.17, respectively. Substrate specificity tests revealed that the enzyme exerts only β-
d
-mannosidase activity. Its kinetic parameters, determined on
para
-nitrophenyl β-
d
-mannopyranoside (
p
NP-βM) substrate were as follows:

K
m

= 180 μM and
V
max
= 5.96 μmol min
−1
mg
−1
; the inhibition constant for mannose was

K
i

= 5.5 mM. Glucono-lacton had no effect on the enzyme activity. A moderate
trans
-glycosidase activity was also observed when the enzyme was incubated in the presence of
p
NP-αM and
p
NP-βM; under these conditions mannosyl groups were transferred by the enzyme from
p
NP-βM to
p
NP-αM resulting in the synthesis of small amounts (1 to 2%) of disaccharides.