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  • Biochemistry and Biotechnology  (17)
  • Barium  (11)
  • Wiley-Blackwell  (28)
  • 1990-1994  (28)
  • 1970-1974
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  • 1
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Targeting to specific sites of the body via colloidal carriers is sought in order to reduce drug side effects. The adsorption of plasma proteins on intravenously injected particles is regarded as the key factor in explaining their organ distribution: total bound protein, or, more likely, the presence of specific proteins and their conformation, are expected to influence macrophage uptake. Polystyrene beads, 60 nm in diameter, were used as model carriers; their surface was differentially modified by adsorption of increasingly hydrophilic block copolymers, poloxamers 184, 188 and 407. After incubation in plasma, the patterns of protein adsorption onto coated beads were analyzed by high-resolution two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). The behavior of some representative proteins was monitored, including albumin, fibrinogen, IgG, factor B and the apolipoproteins, A-I, A-IV, C-III, E and J. The more hydrophobic the particles, the larger the total amount of bound protein. However, this correlation was not valid for all of the analyzed protein species, which proves that it is insufficient to look only at physico-chemical data to predict organ distribution. On the contrary, it is essential to use 2-D PAGE to establish the correlation between adsorbed proteins and carrier behavior in vivo.
    Additional Material: 5 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 40 (1992), S. 991-996 
    ISSN: 0006-3592
    Keywords: lymphocytes ; space biology ; bioprocessing in space ; interferon ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A technology has been developed to achieve optimal attachment of adhesion-independent lymphocytes to microcarrier beads. The activation of T-lymphocytes by concanavalin A was tested under microgravity conditions in an experiment carried out in space during the first Spacelab Life Science Mission. Activation, measured as the synthesis of deoxyribonucleic acid (DNA) and the production of interferon-gamma, more than doubled in attached lymphocytes in microgravity. The depression of the activation discovered in previous space experiments is due to an impairment not of the lymphocyte but of the macrophage function. The system described here may be useful for radiobiological investigations on the effect of high-energy particles and for testing the efficiency of the immune system in humans during the long-duration space flight planned in the future. The biotechnological significance of the increased lymphokine production in space remains to be assessed. © 1992 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 39 (1992), S. 1161-1170 
    ISSN: 0006-3592
    Keywords: bacterial colonization ; kinetic rates ; solidwater interfaces ; Pseudomonas aeruginosa ; Pseudomonas fluorescens ; image analysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The processes leading to bacterial colonization on solidwater interfaces are adsorption, desorption, growth, and erosion. These processes have been measured individually in situ in a flowing system in real time using image analysis. Four different substrata (copper, silicon, 316 stainless-steel and glass) and 2 different bacterial species (Pseudomonas aeruginosa and Pseudomonas fluorescens) were used in the experiments. The flow was laminar (Re = 1.4) and the shear stress was kept constant during all experiments at 0.75 N m-2. The surface roughness varied among the substrata from 0.002 μm (for silicon) to 0.015 μm (for copper). Surface free energies varied from 25.1 dynes cm-1 for silicon to 31.2 dynes cm-1 for copper. Cell curface hydrophobicity, reported as hydrocarbon partitioning values, ranged from 0.67 for Ps. fluorescens to 0.97 for Ps. aeruginosa.The adsorption rate coefficient varried by as much as a factor of 10 among the combinations of bacterial strain and substratum material, and was positively correlated with surface free energy, the surface roughness of the substratum, and the hydrophobicity of the cells. The probability of desorption decreased with increasing surface free energy and surface roughness of the substratum. Cell growth was inhibited on copper, but replication of cells overlying an initial cell layer was observed with increased exposure time to the cell-containing bulk water. A mathematical model describing cell accumulation on a substratum is presented.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 43 (1994), S. 267-274 
    ISSN: 0006-3592
    Keywords: microbial souring ; sulfate reduction ; porous media ; kinetics ; stoichiometry ; transport phenomena ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An anaerobic upflow porous media biofilm reactor was designed to study the kinetics and stoichiometry of hydrogen sulfide production by the sulfate-reducing bacterium (SRB) Desulfovibrio desulfuricans (ATCC 5575) as the first step for the modeling and control of formation souring (H2S) in oil field porous media. The reactor was a packed bed (50 × 5.5 cm) tubular reactor. Sea sand (140 to 375 μm) was used as the porous media. The initial indication of souring was the appearance of well-separated black spots (precipitates of iron sulfide) in the sand bed. The blackened zones expanded radially and upward through the column. New spots also appeared and expanded into the cone shapes. Lactate (substrate) was depleted and hydrogen sulfide appeared in the effluent.Analysis of the pseudo-steady state column shows that there were concentration gradients for lactate and hydrogen sulfide along the column. The results indicate that most of the lactate was consumed at the front part of the column. Measurements of SRB biomass on the solid phase (sand) and in the liquid phase indicate that the maximum concentration of SRB biomass resided at the front part of the column while the maximum in the liquid phase occurred further downstream. The stoichiometry regarding lactate consumption and hydrogen sulfide production observed in the porous media reactor was different from that in a chemostat. After analyzing the radial dispersion coefficient for the SRB in porous media and kinetics of microbial growth, it was deduced that transport phenomena dominate the souring process in our porous media reactor system. © 1994 John Wiley & Sons, Inc.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 44 (1994), S. 263-269 
    ISSN: 0006-3592
    Keywords: microbial souring ; sulfate reduction ; porous media ; kinetics ; biotransformation ; oil reservoir ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Microbial souring (H2S production) in porous media was investigated in an anaerobic upflow porous media reactor at 60°C using microbial consortia obtained from oil reservoirs. Multiple carbon sources (formate, acetate, propionate, iso- and n-butyrates) found in reservoir waters as well as sulfate as the electron acceptor was used. Kinetics and rates of souring in the reactor system were analyzed. Higher volumetric substrate consumption rates (organic acids and sulfate) and a higher volumetric H2S production rate were found at the from part of the reactor column after H2S production had stabilized. Concentration gradients for the substrates (organic acids and sulfate) and H2S were generated along the column. Biomass accumulation throughout the entire column was observed. The average specific sulfate reduction rate (H2S production rate) in the present reactor after H2S production had stabilized was calculated to be 11062 ±2.22 mg sulfate-S/day g biomass. © 1994 John Wiley & Sons, Inc.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 35 (1990), S. 1006-1010 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The formation of alkyl β-D-fructofuranosides by invertase from sucrose in aqueous solutions of methanol, ethanol, or n-propanol is studied for the dependence on alcohol and invertase concentrations as well as on reaction time. The yield of alkyl β-D-fructosides is shown to be controlled by three competitive reactions: the alcoholysis of sucrose, the hydrolysis of sucrose, and the hydrolysis of alkyl β-D-fructosides. Both the conversion rate of sucrose and the fraction of alkyl β-D-fructosides in the product mixture are dependent on the chain length of the alcohols. They decrease in the sequence methanol 〉 ethanol 〉 n-propanol. Alkyl β-D-fructosides are also formed by invertase starting from alcoholic solutions of fructose.
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  • 7
    ISSN: 0006-3592
    Keywords: oxygen profiles ; oxygen microprobe ; Po2-microelectrode ; artifacts ; alginate beads ; Saccharomyces cerevisiae ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Polarographic microcoaxial needle electrodes were used to measure internal profiles of dissolved oxygen tension (Po2) within single Ca-alginate beads of different diameter containing entrapped cells of Saccharomyces cerevisiae. For the investigations, single beads coming from variable growing conditions and distinct cultivation stages were fixed in a special holding device. In dependence on microbial growth steep oxygen gradients were observed. The Oxygen penetration depth at steady state lay between 50 and 100 μm. After 8 h of cultivation time, the anaerobic space within the beads (φ 2 mm; cultivation in a packed bed reactor) is beginning at ∼ 130 μm, whereas the anaerobic space within the beads (φ 2 mm) coming from the shaker flask culture is located ∼440 μm below the bead surface. Surprisingly, steep gradients were also observed, when recording profiles from cell-free Ca-alginate beads of different diameter and alginate concentrations. The steep oxygen gradients apparently had to be interpreted as pseudo-Po2-gradients. These results were borne by several effects, such as formation of artifacts and diffusion barriers in front of the electrode tip or oxygen “availability” at the tip and consumption of oxygen by the electrode itself. These phenomena could be documented by microscopic observation and photography. Thus, to obtain real Po2-profiles it is important to be exactly informed about the physical, chemical, and biological properties of the material to be investigated. Furthermore, it is necessary to apply a special stepwise puncture technique with distinct step-in/step-out movements of the electrode: e.g., unidirectional or contradirectional puncture techniques. © 1994 John Wiley & Sons, Inc.
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Bioluminescence and Chemiluminescence 8 (1993), S. 307-313 
    ISSN: 0884-3996
    Keywords: Luminol ; sodium hypochlorite ; hydrogen peroxide ; inhibition of chemiluminescence ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Two different mechanisms of inhibition of chemiluminescence in the oxidation of luminol by sodium hypochlorite were found. Most substances investigated in these experiments acted by scavenging NaOCI. This mechanism was independent of the concentration of hydrogen peroxide and the incubation time between luminol and inhibitors. The most potent inhibitors were substances containing SH groups. Compounds with amino groups as a target for HOCI/OCI- to yield chloramines were much less effective inhibitors. Another mechanism of inhibition was found for catalase. It depended on the presence of hydrogen peroxide in the incubation medium and the incubation time between luminol and catalase. The enzyme inhibited the luminescence by removing H2O2 at molar concentrations much smaller than those found for all other inhibitors. Our results confirm the present models of the mechanism of generation of luminescence in luminol oxidation.
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Bioluminescence and Chemiluminescence 5 (1990), S. 25-30 
    ISSN: 0884-3996
    Keywords: Chemiluminescence ; Pholas dactylus ; prosthetic group ; flavin ; fluorescence spectrum ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Pholasin is the photoprotein extracted from the marine bivalve Pholas dactylus. It undergoes an oxidative chemiluminescent reaction to oxypholasin with superoxide anion, hypochlorite, peroxidases and other oxidants. Since the observed absorbance and chemiluminescent emission spectra of pholasin solutions cannot be brought about solely by the amino acids composing the protein, there has to be a chemiluminescent chromophore. However, little is known about the chemical nature of this molecule. This work seeks to identify the chemical structure of the luminescent prosthetic group of pholasin.Pholasin could not be reactivated using chromophores from the hydroid Obelia geniculata (coelenterazine) and from the ostracod shrimp Vargula (formerly Cypridina) hilgendorfi. Furthermore, the reaction product of the Vargula chromophore could not be detected in solutions containing oxypholasin. Fluorescence analysis of such a solution revealed a compound with an emission spectrum (γmax 480 nm; excitation at 320 nm), resembling the emission spectrum of the chemiluminescent reaction. This fluorescent substance was separated by gel filtration. It exhibited an apparent molecular mass of 〈 2000. Fluorescence masurements of extracts of partially purified pholasin suggested that a flavin moiety may be involved in pholasin luminescence.
    Additional Material: 5 Ill.
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  • 10
    ISSN: 0884-3996
    Keywords: Platelet-activating factor ; respiratory burst ; chemiluminescence ; luminol ; eosinophils ; neutrophils ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Luminol chemiluminescence was used to detect activation of the respiratory burst oxidase in bovine eosinophils and neutrophils. Extracellular and intracellular chemiluminescence were measured by supplementing the medium with horseradish peroxidase and catalase, respectively. Pure bovine eosinophils (〉 90%), maximally stimulated with 1 nmol/l phorbol 12-myristate-13-acetate (PMA) showed ten times more extracellular luminol-dependent chemiluminescence (CL) than maximally stimulated pure bovine neutrophils (〉 96%). Extracellular CL from eosinophils was preferably induced over intracellular CL by both PMA (27-fold difference) and platelet-activating factor (PAF) at 2 μmol/l (9-fold difference), but not by calcium ionophore A23187 (15 μmol/l).Time course information was used in the following experiments to distinguish between the mode of action of various stimulants. A progressively longer lag period was observed in eosinophil suspensions treated with decreasing doses of PMA, whereas platelet-activating factor induced a dose-dependent increase in the maximum response with no change in time to peak CL. The time course of extracellular CL was almost identical to intracellular CL for all stimulants tested, providing no evidence to suggest that extracellular CL stems from a different enzyme system than intracellular CL.Eosinophils generated most extracellular CL when stimulated with PMA, whereas neutrophils were most efficiently stimulated with A23187, which induced intracellular CL in eosinophils as well as in neutrophils. This accords with the greater tendency of neutrophils to ingest and kill microorganisms, whereas eosinophils are armed to destroy large extracellular targets.
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