bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compartmentalization of proteinases and amylases in Nauphoeta cinerea midgut
Authors: Elpidina Elena N. , Vinokurov Konstantin S. , Gromenko Viktor A. , Rudenskaya Yuliya A. , Dunaevsky Yakov E. , Zhuzhikov Dmitry P. 
Published: August 2002

AbstractCompartmentalization of proteinases, amylases, and pH in the midgut of Nauphoeta cinerea Oliv. (Blattoptera:Blaberidae) was studied in order to understand the organization of protein and starch digestion. Total proteolytic activity measured with azocasein was maximal at pH 11.5 both in anterior (AM) and posterior (PM) halves of the midgut, but the bulk of activity (67%) was found in PM. Total AM and PM preparations were fractionated on a Sephadex G‐50 column and further analysed by means of activity electrophoresis and specific inhibitors and activators. The major activity in PM was classified as an unusual SH‐dependent proteinase with Mr 24,000 and pH optimum with synthetic substrate BApNA at 10.0. The enzyme was 43‐fold activated in the presence of 1 mM DTT, insensitive to synthetic inhibitors of serine (PMSF, TLCK, TPCK) and cysteine (IAA, E‐64) proteinases, strongly inhibited by STI, and displayed four active bands on zymograms. In PM, activities of trypsin‐like, chymotrypsin‐like, subtilisin‐like, and cysteine proteinases were observed. Aspartic and metalloproteinases were not detected. In AM, activity of unusual SH‐dependent proteinase also dominated and activity of chymotrypsin‐like proteinase was observed, but their levels were much lower than in PM. Distribution of amylase activity, exhibiting an optimum at pH 6.0, was quite the opposite. The major part of it (67%) was located in AM. Treatment of amylase preparation with proteinases from AM and PM reduced amylase activity twofold. pH of the midgut contents was 6.0–7.2 in AM, 6.4–7.6 in the first and 8.8–9.3 in the second halves of PM. Thus, pH in AM is in good agreement with the optimal pH of amylase, located in this compartment, but the activity of proteinases, including the ability to degrade amylase, in such an environment is low. Active proteolysis takes place in the second half of PM, where pH of the gut is close to the optimal pH of proteinases. Arch. Insect Biochem. Physiol. 48:206–216, 2001. © 2001 Wiley‐Liss, Inc.
Purification and characterization of biliverdin‐binding vitellogenin from the hemolymph of the common cutworm, Spodoptera litura
Authors: Maruta Kousei , Yoshiga Toyoshi , Katagiri Chihiro , Ochiai Masanori , Tojo Sumio 
Published: August 2002

AbstractBiliverdin‐binding vitellogenin (Vg) was purified from adult female hemolymph of the common cutworm, Spodoptera litura, by using gel filtration and ion exchange chromatographies. The molecular mass of the protein was 490 kDa and it was composed of two 188‐kDa subunits. Three internal amino acid sequences obtained by digestion of the protein with lysylendopeptidase showed high similarity to those of Bombyx mori Vg, supporting the purified blue protein to be vitellogenin. Iatroscan analyses demonstrated the presence of biliverdin in Vg that occupied 2.4% of total lipid components. Among the lipids of Vg (9.5 μg total lipids per 100 μg protein), diacylglycerol was the most predominant, followed by phospholipid, hydrocarbons, and then triacylglycerol, while in biliverdin‐binding proteins (BPs) purified from larval hemolymph (3.1 μg total lipids per 100 μg protein), phospholipid was the most abundant lipid followed by diacylglycerol; hydrocarbons and triacylglycerol were minor components. Vg was first detected in the hemolymph of female pupae one day before eclosion, but injection of 5 μg of methoprene into a 3‐day‐old pupa induced Vg in the hemolymph 4 days earlier than in the control. Methoprene also induced a faster decline in BP‐A and BP‐B titers in the hemolymph with a corresponding increase of the Vg titer. These results suggest that juvenile hormone (JH) induces not only vitellogenesis but also the uptake of these proteins by stimulating the metamorphosis of fat body during the pupal stage. Arch. Insect Biochem. Physiol. 50:97–106, 2002. © 2002 Wiley‐Liss, Inc.
Archaeological site investigation by geoelectrical measurements in Tel‐Halawi (northern Syria)
Authors: Chouker Faris 
Published: August 2002

AbstractAbout 100 vertical electrical soundings (VES) were made at Tel‐Halawi hill on the left bank of the Euphrates just before it flows into the Assad Lake in northern Syria. The VES stations were distributed, at 2 m spacing, along nine profiles (10 m apart), covering the southern part of the site. The electrode array adopted was a modified Schlumberger configuration (pole–dipole array with the B‐electrode placed far enough to be of negligible effect). During every sounding potential electrodes (MN) were fixed symmetrically on both sides of VES point location O (MO = ON = 0.25 m), whereas the current electrode A was moved away with the following distances from the MN midpoint: OA = 1, 1.5, 2, 3, 4, 5, 7 and 10 m.The resistivity data measured were then treated and plotted in the field as resistivity cross‐sections of different pseudodepths, showing the specific influence of the buried targets at different depths. This procedure, although time consuming, looks a very promising technique for discovering near‐surface targets through resistivity survey. This method reflects successively the resistivity contribution of the buried targets according to their depth, separating them with regard to the depth of burial. It offers also higher reliability of results, owing to the confirmed response of buried targets as related multiple anomalies on several resistivity cross‐sections with gradually increasing depths. Many of these anomalies measured along the resistivity profiles were verified through excavation work. Copyright © 2001 John Wiley & Sons, Ltd.
A genetic attack on the defense complex
Authors: Gibson Greg 
Published: August 2002

AbstractAn increasing number of “non‐model” organisms are becoming accessible to genetic analysis in the field, as evolutionary biologists develop dense molecular genetic maps. Peichel et al.'s recent study1 provides a microsatellite‐based map for threespine stickleback fish (Gasterosteus aculeatus), and the first evidence for QTL affecting feeding morphology and defensive armor. This species has undergone rapid and parallel morphological and behavioral evolution, and there is now hope that some of the genes responsible for the divergence may soon be identified. BioEssays 24:487–489, 2002. © 2002 Wiley Periodicals, Inc.
Conformational studies of Lewis X and Lewis A trisaccharides using NMR residual dipolar couplings
Authors: Azurmendi Hugo F. , Martin‐Pastor Manuel , Bush C.Allen 
Published: August 2002

AbstractThe conformations of the histo‐blood group carbohydrate antigens Lewis X (Lex) and Lewis A (Lea) were studied by NMR measurements of one‐bond C—H residual dipolar couplings in partially oriented liquid crystal solutions. A strategy for rapid calculation of the difference between theoretical and experimental dipolar couplings of a large number of model structures generated by computer simulations was developed, resulting in an accurate model structure for the compounds. Monte Carlo simulations were used to generate models for the trisaccharides, and orientations of each model were sought that could reproduce the experimental residual dipolar coupling values. For both, Lea and Lex, single low energy models giving excellent agreement with experiment were found, implying a compact rigidly folded conformation for both trisaccharides. The new approach was also applied to the pentasaccharides lacto‐N‐fucopentaose 2 (LNF‐2) and lacto‐N‐fucopentaose 3 (LNF‐3) proving its consistency and robustness. For describing the conformation of tightly folded oligosaccharides, a definition for characterization of ring planes in pyranoside chairs is proposed and applied to the analysis of the relation between the fucose and galactose residues in the epitopes, revealing the structural similarity between them. © 2002 John Wiley & Sons, Inc. Biopolymers 63: 89–98, 2002
Raman spectroscopy investigation of biological materials by use of etched and silver coated glass fiber tips
Authors: Gessner R. , Rösch P. , Kiefer W. , Popp J. 
Published: August 2002

AbstractThe results for surface enhanced Raman scattering (SERS) studies on biological samples are reported. Etched and silver coated glass fiber tips were used as a SERS substrate. This method enabled the recording of spectra of biological samples, such as plant tissue or microbiological cells, with a high spatial resolution. Because of the low laser power used with the fiber tips, it was even possible to investigate tissues that are very sensitive toward laser power as it is used in a common micro‐Raman setup. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 327–330, 2002
Femtosecond coherent Raman spectroscopy and its application to porphyrins
Authors: Schmitt M. , Heid M. , Schlücker S. , Kiefer W. 
Published: August 2002

AbstractThe results on femtosecond time‐resolved coherent anti‐Stokes Raman scattering (CARS) experiments for the analysis and control of ground state vibrational dynamics of porphyrin systems are briefly reviewed. By detecting the spectrum of the transient CARS signal, a detailed mapping of the dynamics initiated by the stimulated Raman pump process is achieved. The method yields the dephasing behavior and spectral information of the investigated system at the same time. The different contributions to the ground state vibrational dynamics are selected by changing the direction of the CARS signal analyzer in the polarization arrangement used. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 226–232, 2002
Laser scanning microscopy study on adsorption of biologically relevant proteins on implant materials
Authors: Schöller M. , Hauck A. , Thull R. , Steinmeyer R. , Hedrich R. , Schneider F. W. , Kiefer W. , Popp J. 
Published: August 2002

AbstractThe adsorption of proteins at implant surfaces plays a key role in osseointegration and is therefore of great importance in biomaterial science. Laser scanning microscopy (LSM) is described, a method that is used here for the first study of the adsorption of proteins on implant surfaces. These LSM measurements provide information on the surface morphology, and the spatial distribution of adsorbed proteins can be deduced. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 344–348, 2002
Vibrational circular dichroism spectroscopy study of paroxetine and femoxetine precursors
Authors: Urbanová Marie , Setnička Vladimír , Bouř Petr , Navrátilová Hana , Volka Karel 
Published: August 2002

AbstractThe solution structures of (3R,4S)‐ and (3S,4R)‐ 4‐(4‐fluorophenyl)‐3‐hydroxylmethyl‐ 1‐methylpiperidine, which are intermediates in the synthesis of the two pharmaceuticals paroxetine and femoxetine, were studied by vibrational circular dichroism (VCD) spectroscopy. In addition, six derivatives with different substituents attached to the C3 atom were prepared and their VCD and absorption spectra discussed with the aid of ab initio simulations. The VCD spectra were found to be sensitive to the geometry changes. In addition, a subtle variation caused by intermolecular aggregation was apparent in the spectra. The VCD technique can be applied for structural analysis of chiral pharmaceuticals in solutions. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 298–301, 2002
A microbial chip combined with scanning electrochemical microscopy
Authors: Kaya Takatoshi , Nishizawa Matsuhiko , Yasukawa Tomayuki , Nishiguchi Masashi , Onouchi Tooru , Matsue Tomokazu 
Published: August 2002

AbstractA microbial chip for bioassay was fabricated and its performance was characterized by scanning electrochemical microscopy (SECM). The microbial chip was prepared by spotting a suspension of Escherichia coli on a polystyrene substrate by using a glass capillary pen. The respiration activity of the E. coli spot was imaged with SECM by mapping the oxygen concentration around the spot. The SECM images of the microbial chips clearly showed spots with lower reduction currents, indicating that E. coli in the spots uptake oxygen by respiration. The bactericidal effects of antibiotics (streptomycin and ampicillin) were measured using the E. coli‐based microbial chip, and discussed in comparison with the minimum inhibitory concentration (MIC) determined by an agar plate dilution method. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 391–394, 2001.
Fluorescent proteins in animal cells for process development: Optimization of sodium butyrate treatment as an example
Authors: Hunt Lisa , Batard Pascal , Jordan Martin , Wurm Florian M. 
Published: August 2002

AbstractFluorescent proteins expressed in mammalian cells can be quantified quickly and noninvasively with a standard fluorescence plate reader. We have previously exploited this quality in cell growth assessment (Hunt et al., 1999b). In this work, different CHO cell lines constitutively expressing fluorescent proteins were evaluated as model systems for process development and optimization. Our results demonstrate that the fluorescence of these cell lines quickly reveals conditions that might improve the overall productivity.Sodium butyrate, a well‐known yet unpredictable enhancer of production, was chosen for this study. Due to the competing effects of sodium butyrate (“butyrate”) on expression and cell number, the maximal overall productivity represents a compromise between enhancement of production and toxicity. Based on fluorescence only, it is possible to separate effects on cell number and specific production by combining microplate fluorescence measurements with data obtained by flow cytometry. This allows for rapid screening of different clones without counting cells or quantifying the recombinant protein, a highly attractive feature if the expression of green fluorescent protein (GFP) was correlated to that of a protein of interest.For all clones tested, negative effects of butyrate on proliferation were similar, while net enhancement of expression was characteristic for each clone. Therefore, it is necessary to optimize treatment for each individual clone. This work demonstrates that, based on the fluorescence of GFP‐expresssing cell lines, it is possible to examine noninvasively three critical, generic parameters of butyrate treatment: butyrate concentration, exposure time, and culture phase at the time of addition. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 528–537, 2002; DOI 10.1002/bit.10108
Stoichiometric model for evaluating the metabolic capabilities of the facultative methylotroph Methylobacterium extorquens AM1, with application to reconstruction of C3 and C4 metabolism
Authors: Van Dien Stephen J. , Lidstrom Mary E. 
Published: August 2002

AbstractA stoichiometric model of central metabolism was developed based on new information regarding metabolism in this bacterium to evaluate the steady‐state growth capabilities of the serine cycle facultative methylotroph Methylobacterium extorquens AM1 during growth on methanol, succinate, and pyruvate. The model incorporates 20 reversible and 47 irreversible reactions, 65 intracellular metabolites, and experimentally‐determined biomass composition. The flux space for this underdetermined system of equations was defined by finding the elementary modes, and constraints based on experimental observations were applied to determine which of these elementary modes give a reasonable description of the flux distribution for each growth substrate. The predicted biomass yield, on a carbon atom basis, is 49.8%, which agrees well with the range of published experimental yield measurements (37–50%). The model predicts the cell to be limited by reduced pyridine nucleotide availability during methylotrophic growth, but energy‐limited when growing on multicarbon substrates. Mutation and phenotypic analysis was used to explore a previously unknown region of the metabolic map and to confirm the stoichiometry of the pathways in this region used in the metabolic model. Based on genome sequence data and simulation results, three enzymes involved in C3–C4 interconversion pathways were predicted to be mutually redundant: malic enzyme, phosphoenolpyruvate carboxykinase, and phosphoenolpyruvate synthase. Insertion mutations in the genes predicted to encode these enzymes were made and these mutants were capable of growing on all substrates tested, confirming the redundancy of these pathways. Likewise, pathway analysis suggests that the TCA cycle enzymes citrate synthase and succinate dehydrogenase are essential for all growth substrates. In keeping with these predictions, null mutants could not be obtained in these genes. Finally, a similar model was developed for the ribulose monophosphate pathway obligate methylotroph Methylobacillus flagellatum KT to compare the efficiency of carbon utilization in the two types of methylotrophic carbon utilization pathways. The predicted yield for this organism on methanol is 65.9%. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 296–312, 2002.
Relationship between cell proliferation, cell‐cycle phase, and retroviral vector production in FLYRD18 human packaging cells
Authors: McTaggart S. , Al‐Rubeai M. 
Published: August 2002

AbstractThe relatively low concentrations of retroviral vectors produced by most packaging cells requires the optimization and intensification of their production to make a commercially viable product for gene therapy. While a number of reports exist concerning target cell‐cycle effects on retroviral vector infection efficiency, no studies have been reported on the effects of packaging cell cycle on vector production. We have studied the effect of proliferation of the human packaging cell line, FLYRD18, on vector production. In addition, the titer levels of vector produced by cells in each phase of the cell cycle were compared. Numerous studies suggested progression of the cells through the cell cycle to be essential for vector production. However, vector release was found not to be predominant in any particular phase of the cell cycle. These findings indicate that packaging cell proliferation is important for optimal virus production and that arrest of the cells in any particular phase of the cell cycle affords no benefits in retroviral vector production. In contrast to previous reports (using other cell lines), we observed no temporary inhibition of cell cycle progression after detachment of cells from their substratum and that virus production occurred immediately after re‐plating of the cells. The findings in this report are important for determining the optimal culture conditions for vector production by packaging cells in vitro. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 52–60, 2001.
Investigation of cell exudates active in carbon tetrachloride and chloroform degradation
Authors: Koons Brad W. , Baeseman Jenny L. , Novak Paige J. 
Published: August 2002

AbstractContamination of groundwater by chlorinated solvents such as carbon tetrachloride (CCl4) and chloroform (CHCl3) is a widespread problem. The cell exudates from the methanogen Methanosarcina thermophila are active in the degradation of CCl4 and CHCl3. This research was performed to characterize these exudates. Examination of the influence of pH indicated that activity was greater under alkaline conditions. Rapid CCl4 degradation occurred from 35–65°C, with first‐order degradation rate coefficients increasing as temperature increased. It was found that proteins were not responsible for CCl4 degradation. The active agents in the cell exudates were <10 kDa in size, with degradation activity present in both 1–10 kDa and <1 kDa size ranges. Upon purification of the <10 kDa size range of the cell exudates on a C18 chromatography column, 17 fractions (out of 100) degraded >50% of the added CCl4 in 8 h. These 17 fractions were pooled into three samples based on their elution time from the C18 column. One of these pooled samples contained elevated levels of cobalt, zinc, and iron, at 2, 3, and 13 times the levels measured in similarly fractionated and pooled samples of medium, respectively. The UV‐visible spectrum of this pooled sample had an absorption maximum at 560–580 nm, which is similar to the absorption maxima of heme (approximately 550 and 575 nm). The two other pooled samples contained elevated levels of zinc at 11 and 22 times the concentration measured in similarly fractionated and pooled samples of medium, respectively, and also contained very low levels of nickel, cobalt, and iron. This research suggests that the cell exudates from M. thermophila contain porphorinogen‐type molecules capable of dechlorination, possibly excreted corrinoids, hemes, and zinc‐containing molecules. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74; 12–17, 2001.
Electrokinetic movement and biodegradation of 2,4‐dichlorophenoxyacetic acid in silt soil
Authors: Jackman Simon A. , Maini Giacomo , Sharman Ajay K. , Sunderland Garry , Knowles Christopher J. 
Published: August 2002

AbstractThe coupling of electrokinetic movement of an organic contaminant, 2,4‐dichlorophenoxyacetic acid (2,4‐D), through soil and its biodegradation in situ has been demonstrated. In a first experiment, the direction and rate of movement of 2,4‐D were determined using homogeneously contaminated soil (864 mg 2,4‐D/kg dry weight soil) compacted into six individual compartments, 6 cm long, 3 cm wide, and 4 cm deep. Each compartment was bordered by a carbon felt anode and a stainless steel cathode. The application of a current density of 3.72 A/m2 led to migration of 2,4‐D towards the anode at a rate of approximately 4 cm/day. In a second experiment, electrokinetic movement and biodegradation were combined in situ. Sterilized silt soil contaminated with ring‐labeled 14C‐2,4‐D (811 mg 2,4‐D/kg dry weight soil) was compacted into a single soil compartment, 22 cm long, 7 cm wide, and 4 cm deep, in a 4.5 cm region adjacent to the cathode. The remainder of the compartment was filled with sterilized soil (to a total weight of 1,015 g). Burkholderia spp. RASC c2 (1.88 × 1011 cells), a tetracycline‐resistant bacterium with chromosomally encoded degradative genes for 2,4‐D, was inoculated into the soil at a position 14–16 cm from the cathode. The reactor was placed within a sealed perspex box, with a constant air flow connected to sodium hydroxide traps. Under an applied current density of 0.89 A/m2, the pollutant moved towards the bacteria. As it reached the inoculated region, its concentration decreased in the soil and 14CO2 was recovered in the traps. At the end of the experiment, 87.1% of radiolabel had been removed from the soil, 5.8% of which was recovered as 14CO2. A third, control, experiment showed a significant contrast in the absence of an electric current, where a slow rate of diffusion controlled the movement of both 2,4‐D and bacteria in the soil and biodegradation occurred at the interface between the diffusing fronts. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 40–48, 2001.