Library

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1985-1989  (519)
  • 1986  (519)
  • Biochemistry and Biotechnology  (519)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986) 
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 1-1 
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 2-3 
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 4-15 
    ISSN: 0887-3585
    Keywords: membrane biomimetic system ; reverse micelles ; interfacial water ; myelin proteins ; solid enzyme activity ; organic solvents ; biotechnology ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 16-22 
    ISSN: 0887-3585
    Keywords: protein design ; alpha-helical bundle ; x-ray crystallography ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Twelve- and sixteen-residue peptides have been designed to form tetrameric alphahelical bundles. Both peptides are capable of folding into amphiphilic alpha-helices, with leucyl residues along one face and glutamyl and lysyl residues along the opposite face. Four such amphiphilic alpha-helices are capable of forming a noncovalently bonded tetramer. Neighboring helices run in antiparallel directions in the design, so that the complex has 222 symmetry. In the designed tetramer, the leucyl side chains interdigitate in the center in a hydrophobic interaction, and charged side chains are exposed to the solvent. The designed 12-mer(ALPHA-1) has been synthesized, and it forms helical aggregates in aqueous solution as judged by circular dichroic spectroscopy. It has also been crystallized and characterized by x-ray diffraction. The crystal symmetry is compatible with (but does not prove) the design. The design can be extended to a four-alpha-helical bundle formed from a single polypeptide by adding three peptide linkers.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 23-33 
    ISSN: 0887-3585
    Keywords: peptide helix ; protein stability ; framework model of folding ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Recent work has shown that, with synthetic analogues of C-peptide (residues 1-13 of ribonuclease A), the stability of the peptide helix in H2O depends strongly on the charge on the N-terminal residue. We have asked whether, in semisynthetic ribonuclease S reconstituted from S-protein plus an analogue of S-peptide (1-15), the stability of the peptide helix is correlated with the Tm of the reconstituted ribonuclease S. Six peptides have been made, which contain Glu9 → Leu, a blocked α-COO- group (—CONH2), and either Gln11 or Glu11. The N-terminal residue has been varied; its charge varies from +2 (Lys) to -1 (succinyl-Ala). We have measured the stability of the peptide helix, the affinity of the peptide for S-protein (by C.D. titration), and the thermal stability of the reconstituted ribonuclease S.All six peptide analogues show strongly enhanced helix formation compared to either S-peptide (1-15) or (1-19), and the helix content increases as the charge on the N-terminal residue changes from +2 to -1. All six peptides show increased affinity for S-protein compared to S-peptide (1-19), and all six reconstituted ribonucleases S show an increase in Tm compared to the protein with S-peptide (1-19). The Tm increases as the charge on residue 1 changes from +2 to -1. The largest increment in Tm is 6°.The results suggest that the stability of a protein can be increased by enhancing the stability of its secondary structure.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 34-42 
    ISSN: 0887-3585
    Keywords: hydrogen exchange ; BPTI ; folding pathway ; protein dynamics ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A method to be used for experimental studies of protein folding introduced by Schmid and Baldwin (J. Mol. Biol. 135: 199-215, 1979), which is based on the competition between amide hydrogen exchange and protein refolding, was extended by using rapid mixing techniques and 1H NMR to provide site-resolved kinetic information on the early phases of protein structure acquisition. In this method, a protonated solution of the unfolded protein is rapidly mixed with a deuterated buffer solution at conditions assuring protein refolding in the mixture. This simultaneously initates the exchange of unprotected amide protons with solvent deuterium and the refolding of protein segments which can protect amide groups from further exchange. After variable reaction times the amide proton exchange is quenched while folding to the native form continues to completion. By using 1H NMR, the extent of exchange at individual amide sites is then measured in the refolded protein. Competition experiments at variable reaction times or variable pH indicate the time at which each amide group is protected in the refolding process. This technique was applied to the basic pancreatic trypsin inhibitor, for which sequence-specific assignments of the amide proton NMR lines had previously been obtained. For eight individual amide protons located in the β-sheet and the C-terminal α-helix of this protein, apparent refolding rates in the range from 15s-1 to 60 s-1 were observed. These rates are on the time scale of the fast folding phase observed with optical probes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 43-46 
    ISSN: 0887-3585
    Keywords: protein stability ; helix-coil ; mutant ; calorimetry ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Oligonucleotide-directed mutagenesis has been used to replace α-helical glycines in the N-terminal domain of λ repressor with alanines. Since alanine is a significantly better helix-forming residue than glycine, these changes were predicted to have a stabilizing effect. We show that the Gly46→Ala substitution, the Gly48→Ala substitution, and the double substitution increase the melting temperature of the N-terminal domain by 3-6°.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 60-65 
    ISSN: 0887-3585
    Keywords: computerized data bank ; sequence comparison heuristics ; databank access ; data bank merging ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Four major protein sequence data collections (NBRF-PIR, PSD-Kyoto, PGtrans, and NEWAT) have been merged into a single nonredundant data bank called PseqIP. The data bank entries were automatically matched by a heuristic computer program relying on the fast computation of the number of tetrapeptides shared by two sequences. PseqIP 1.0 includes 6,068 different protein sequences for a total of 1,357,067 residues, representing most of the available sequence information to date. During the course of this work, we found about 600 occurrences course of a protein sequence recorded with a one-amino-acid variation in at least two different data banks. A flat file (ASCII computer-readable format) version of PseqIP 1.0, well-suited for exhaustive homology searches and statistical sequence analysis, is available from our laboratory.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 47-59 
    ISSN: 0887-3585
    Keywords: protein electrostatics ; substrate diffusion ; Poisson-Boltzmann ; electrostatic potentials ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In this paper we report the implementation of a finite-difference algorithm which solves the linearized Poisson-Boltzmann equation for molecules of arbitrary shape and charge distribution and which includes the screening effects of electrolytes. The microcoding of the algorithm on an ST-100 array processor allows us to obtain electrostatic potential maps in and around a protein, including the effects of ionic strength, in about 30 minutes. We have applied the algorithm to a dimer of the protein Cu-Zn superoxide dismutase (SOD) and compared our results to those obtained from uniform dielectric models based on coulombic potentials. We find that both the shape of the protein-solvent boundary and the ionic strength of the solvent have a profound effect on the potentials in the solvent. For the case of SOD, the cluster of positive charge at the bottom of the active site channel produces a strongly enhanced positive potential due to the focusing of field lines in the channel - a result that cannot be obtained with any uniform dielectric model. The remainder of the protein is surrounded by a weak negative potential. The electrostatic potential of the enzyme seems designed to provide a large cross-sectional area for productive collisions. Based on the ionic strength dependence of the size of the positive potential region emanating from the active site and the repulsive negative potential barrier surrounding the protein, we are able to suggest an explanation for the ionic strength dependence of the activity of the native and chemically modified forms of the enzyme.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 66-73 
    ISSN: 0887-3585
    Keywords: protein domain ; polymerase ; 3′-5′ exonuclease ; artificial gene ; expression vector ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The Klenow fragment of DNA polymerase I from Escherichia coli has two enzymatic activities: DNA polymerase and 3′-5′ exonuclease. The crystal structure showed that the fragment is folded into two distinct domains. The smaller domain has a binding site for deoxynucleoside monophosphate and a divalent metal ion that is thought to identify the 3′-5′ exonuclease active site. The larger C-terminal domain contains a deep cleft that is believed to bind duplex DNA. Several lines of evidence suggested that the large domain also contains the polymerase active site. To test this hypothesis, we have cloned the DNA coding for the large domain into an expression system and purified the protein product. We find that the C-terminal domain has polymerase activity (albeit at a lower specific activity than the native Klenow fragment) but no measurable 3′-5′ exonuclease activity. These data are consistent with the hypothesis that each of the three enzymatic activities of DNA polymerase I from E. coli resides on a separate protein structural domain.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 74-80 
    ISSN: 0887-3585
    Keywords: antibody ; crystal structure ; anti-galactan ; J539 ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The crystal structure of the Fab of the galactan-binding immunoglobulin J539 (a mouse IgA,κ) has been determined at a resolution of approximately 2.6 Å by X-ray diffraction. The starting model was that obtained from the real space search described previously (Navia, M.A., Segal, D.M., Padlan, E.A., Davies, D.R., Rao, D.N., Rudikoff, S. and Potter, M. “Crystal structure of galactan-binding mouse immunoglobulin J539 Fab at 4.5 Å resolution.” Proc. Nat. Acad. Sci. USA, 76:4071-4074, 1979). This Fab structure has now been refined by restrained least-squares procedures to an R-value of 19% for the 11,690 unique reflections between 8.0 Å and 2.6 Å. The rms deviation from ideal bond lengths is 0.025 Å. The overall structure differs from McPC603 Fab, another mouse IgA,κ antibody, in that the elbow bend, relating the variable and constant parts of the molecule, is 145° vs. 133° for McPC603. The region of the molecule expected to be the antigen binding site contains a large cavity with two clefts leading away from it. This has been fitted with a model of an oligo-galactan.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986) 
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 81-89 
    ISSN: 0887-3585
    Keywords: protein stability ; protein denaturation ; denatured state ; structural intermediates ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Eleven mutant forms of staphylococcal nuclease with one or more defined amino acid substitutions have been analyzed by solvent denaturation by using intrinsic fluorescence to follow the denaturation reaction. On the basis of patterns observed in the value of m-the rate of change of log Kapp (the apparent equilibrium constant between the native and denatured states) with denaturant concentration - these proteins can be grouped into two classes. For class I mutants, the value of m with guanidine hydrochloride is less than the wild-type value and is either constant or increases slightly with increasing denaturant; the value of m with urea is also less than wild type but shows a marked increase with increasing denaturant concentration, often approaching but never exceeding the wild-type value. For class II mutants, m is constant and is greater than wild type in both denaturants, with the increase being consistently larger in guanidine hydrochloride than in urea. When double or triple mutants are constructed from members of the same mutant class, the change in m is usually the sum of the changes produced by each mutation in isolation. One plausible explanation for these altered patterns of denaturation is that chain-chain or chain-solvent interactions in the denatured state have been modified - interactions which appear to involve hydrophobic groups.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 90-99 
    ISSN: 0887-3585
    Keywords: visual excitation ; rhodopsin ; enzyme regulation ; cyclic nucleotide cascade ; G-proteins ; inhibitory subunit ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The switching on of the cGMP phosphodiesterase (PDE) in retinal rod outer segments by activated transducin (Tα-GTP) is a key step invisual excitation. The finding that trypsin activates PDE (αβγ) by degrading its γ subunit and the reversal of this activation by γ led to the proposal that Tα-GTP activates PDE by relieving an inhibitory constraint imposed by γ (Hurley and Stryer: J. Biol. Chem. 257:11094-11099, 1982). We report here studies showing that the addition of γ subunit also reverses the activation of PDE by Tα-GTP-γS. A procedure for preparing γ in high yield (50-80%) is presented. Analyses of SDS polyacrylamide gel slices confirmed that inhibitorya activity resides in the γ subunit. Nanomolar γ blocks the activation of PDE by micromolar Tα-GTPγS. The degree of activation of PDE depends reciprocally on the concentrations of γ and Tα-GTPγS. γ remains bound to the disk membrane during the activation of PDE by transducin. The binding of γ to the αβ subunits of native PDE is very tight; the dissociation constant is less than 10 pM, indicating that fewer than 1 in 1,700 PDE molecules in rod outer segments are activated in the absence of Tα-GTP.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 16
    ISSN: 0887-3585
    Keywords: affinity chromatography ; high-performance liquid chromatography ; bacteriophage T4 tail sheath protein ; bacteriophage T4 tail tube protein ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A novel method useful for selective isolation of the C-terminal peptide from a tryptic digestion mixture of a protein has been developed by taking advantage of a unique property of anhydrotrypsin, which has a strong specific affinity for the peptides containing arginine or lysine at their C-termini. Briefly, peptides produced by tryptic digestion of a protein are fractionated by affinity chromatography on a column of immobilized anhydrotrypsin. The C-terminal peptide is recovered in a breakthrough fraction, which the remainders are adsorbed on the column (unless the protein ends in arginine or lysine). The breakthrough fraction is then subjected to reversed-phase high-perfomance liquid chromatography in order to purify the C-terminal peptide. Using this method, we have successfully isolated the C-terminal peptides from tryptic digests of the sheath protein (gp 18) and the tube protein (gp 19) of bacteriophage T4. The analytical results on these peptides, together with the information on the N-terminal structures of the original proteins and on the nucleotide sequences of genes 18 and 19, allowed us to establish the complete primary structures of the two proteins.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 109-115 
    ISSN: 0887-3585
    Keywords: proteins ; protein dynamics ; tryptophan exposure ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Experiments were done to test the thesis that acrylamide and similar small molecules can penetrate into proteins on a nanosecond time scale. The approach taken was to measure the pattern of fluorescence quenching exhibited by quenching molecules differing in molecular character (size, polarity, charge) when these are directed against protein tryptophans that cover the whole range of tryptophan accesibility. If quenching involves protein penetration and internal quencher migration, one expects that larger quenchers and more polar quenchers should display lesser quenching. In fact, no significant dependence on quencher character was found. For proteins that display measurable quenching, the disparate quenchers studied display very similar quenching rate constants when directed against any particular protein tryptophan. For several proteins having tryptophans known to be buried, no quenching occurs. These results are not consistent with the view that the kinds of small molecules studied can quite generally penetrate into and diffuse about within proteins at near-diffusion-limited rates. Rather the results suggest that when quenching is observed, the pathway involves encounters with tryptophans that are partially exposed at the protein surface. Available crystallographic results support this conclusion.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 116-124 
    ISSN: 0887-3585
    Keywords: translational repressor ; in vitro transcription-translation ; gene expression ; protein purification ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The bacteriophage T4 translational represor regA protein has been purified from an overproducing strain, and its activity has been studied in simple in vitro protein synthesis reactions. RegA protein was found to inhibit the translation of T4 genes 44, 45, and ORF45-1 in a concentration-dependent fashion. Expression of two other T4 genes which are insensitive to regA protein in vivo, genes 32 and 43, was unaffected by the presence of regA protein. Specific inhibition of synthesis of genes 44, 45, and ORF 45-1 proteins was achieved with 5-20 μM concentrations of regA protein, without the addition of any other T4 encoded proteins or cofactors. When in vitro protein synthesis was performed in two steps, uncoupling translation from transcription, regA protein had an inhibitory effect regardless of whether it was added at the initiation of transcription or only at the translation step. This indicates that regA protein functions during the translation step of protein synthesis in vitro in agreement with previous in vivo studies of regA protein.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 134-138 
    ISSN: 0887-3585
    Keywords: enzymatic transesterification ; peptide synthesis ; trypsin ; chymotrypsin ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Trypsin and α-chymotrypsin were immobilized to alumina-phosphocolamine complex, activated by glutaraldehyde. The immobilized enzymes show a great stability toward organic solvents miscible or immiscible with water. In the presence of a low concentration of water, the immobilized enzymes catalyzed transesterification reactions as well as peptide synthesis. The synthesized peptides were stable toward the immobilized enzymes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 125-133 
    ISSN: 0887-3585
    Keywords: regulation ; prokaryotic bacteria ; leucine uptake ; leucyl tRNA corepressor ; cell physiology ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The livR gene encoding the repressor for high-affinity branched-chain amino acid transport in Escherichia coli has been cloned from a library prepared from the episome F106. The inserted DNA fragment from the initial cloned plasmid, pANT1, complemented two independent, spontaneously derived, regulatory mutations. Subcloning as well as the creation of deletions with Bal31 exonuclease revealed that the entire regulatory region is contained within a 1.1-kb RsaI-SalI fragment. Expression of the pANT plasmids in E. coli minicells showed that the regulatory region encodes one detectable protein with an apparent molecular weight of 21,000. DNA sequencing revealed one open reading frame of 501 bp encoding a protein with a calculated MW of 19,155. The potential secondary structure of the regulatory protein has been predicted and it suggests that the carboxy terminus may fold into three consecutive alpha helices. These results suggests that the livR gene encodes a repressor which plays a role in the regulation of expression of the livJ and the livK transport genes.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 21
    ISSN: 0887-3585
    Keywords: hypertension ; renin production ; mammalian expression ; affinity chromatography ; genetic engineering ; prorenin secretion ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Transfection of Chinese hamster ovary (CHO) cells with a plasmid containing the cDNA for human preprorenin has provided cell lines that secrete 15 mg of native prorenin per liter of culture medium. Tryptic activation of the prorenin occurs by selective cleavage of the Arg66-Leu67 bond (numbering as in preprorenin). The renin product, purified in a single step and in high yield by affinity chromatography, is fully stable for as long as 8 months when stored in solution at 4°C and pH 6.5. Purity of the renin was judged to be greater than 95% by gel electrophoresis, compositional and N-terminal sequence analyses, and specific enzyme activity. An important aspect of the present work is the development of a direct assay for renin which permits accurate and reproducible evaluation of enzyme units and kinetic parameters. Application of methods described herein, combined with appropriate scale-up fermentation capabilities, provides the means for generating gram quantities of human renin and its zymogen.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 146-163 
    ISSN: 0887-3585
    Keywords: protein conformation ; energy calculations ; protein modeling ; loop conformation ; surface area ; homologous proteins ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The feasibility of determining the conformation of segments of polypeptide chain up to six residues in length in globular proteins by means of systematic search through the possibles conformations has been investigated. Trial conformations are generated by using representative sets of φ, ψ, and χ angels that have been derived from an examination of the distributions of these angles in refined protein structures. A set of filters based on simple rules that protein structures obey is used to reduce the number of conformations to a manageable total. The most important filters are the maintenance of chain integrity and the avoidance of tooshort van der Waals contacts with the rest of the protein and with other portions of the segment under construction. The procedure is intended to be used with approximate models so that allowance is made throughout for errors in the rest of the structure. All possible main chains are first constructed and then all possible side-chain conformations are built onto each of these. The electrostatic energy, including a solvent screening term, and the exposed hyrophobic area are evaluated for each accepted conformation. The method has been tested on two segments of chain in the trypsin like enzyme from Streptomyces griseus. It is found that there is a wide spread of energies among the accepted conformations, and the lowest energy ones have satisfactorily small root mean square deviations from the X-ray structure.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 164-175 
    ISSN: 0887-3585
    Keywords: DPG ; organophosphates ; ligand interactions ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Rate equilibrium dialysis was used to measure the binding of 2,3-diphosphoglycerate (DPG) to human oxy- and deoxyhemoglobin AO over the range pH 5-9, at 21.5°C. This approach yielded an accurate, precise, and self-consistent set of model-independent association constants. These data were successfully fitted to a thermodynamic model which is fuctionally similar to a Hill equation. The isotherms generated by this fitting procedure appear to intersect at low pH and converge at high pH. This apparent convergence at high pH is consistent with results obtained by oxygen equilibria studies performed under conditions of saturating DPG. These calculated isotherms were used to determine the enhancement of the Bohr effect as a function of pH. These results are consistent with data obtained by pH stat measurements by other investigators.This paper presents the first in a series of studies that will provide a systematic characterization of the interaction between hemoglobin and DPG.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 176-187 
    ISSN: 0887-3585
    Keywords: drifted micrographs ; rotational blur ; thin sections ; Wiener filtering ; image analysis ; sickle hemoglobin ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: We have investigated the restoration of electron micrographs exhibiting blurring due to drift and rotation. Blurring due to drift arises in micrographs taken of a specimen which is moving relative to the image plane. A related problem is that of rotational blurring which arises in micrographs of thin sections of helical particles viewed in cross section. The twist of the particle within the finite thickness of the section causes the image to appear rotationally blurred about the helical axis.Restoration algorithms were evaluated by applying them to the restoration of blurred model images degraded by additive Gaussian noise. Model images were also used to investigate how an incorrect estimate of the point spread function function describing the blur would effect the restoration. Images were, if necessary, geometrically transformed to a space in which the point spread function of the blur can be considered as linear and space invariant as, under these conditions, the restoration algorithms are greatly simplified. In the case of the rotationally blurred images this procedur was accomplished by transforming the image to polar coordinates.The restoration techniques were successfully applied to blurred micrographs of bacteriophage T4 and crystals of catalase. The quality of the restoration was judged by comparisons of the restored images to undegraded images. Application to micrographs of rotationally blurred cross sections of helical macrofibers of sickle hemoglobin resulted in a reduction in the amount of rotational blurring.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986) 
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 195-210 
    ISSN: 0887-3585
    Keywords: protein domains ; oligomeric assembly ; RNA splicing ; multiple binding sites ; RNP core proteins ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 27
    ISSN: 0887-3585
    Keywords: G-protein ; phototransduction ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The GTP-binding subunit of transducin (Tα) activates the cGMP phosphodiesterase (PDE) of bovine retinal rods by relieving the constraint imposed by the inhibitory subunit PDEγ. We have isolated and characterized the complex Tα.GTPγS-PDEγ formed when Tα is activated by the nonhydrolyzable analog GTPγS. Sedimentation and light-scattering techniques demonstrate that, in contrast to free Tγ.GTPγS, which is soluble, the Tα.GTPγS-PDEγ complex, as well as Tα.GTP-PDEγ, is membrane bound at cytosolic ionic strength. It is eluted from the membrane at low ionic strength as a monomeric and 1:1 stoichiometric complex. The relative affinities of PDEγ for PDEαβ and for Tα.GTP are discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 211-217 
    ISSN: 0887-3585
    Keywords: protein folding ; α-helix stabilization ; peptide structural stability ; circular dichroism ; protein electrostatics ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The effects of trifluoroethanol (TFE) on the stability of the α-helix formed by ribonuclease S-peptide, residues 1-19 of ribonuclease A, were studied by measuring circular dichroism as a function of TFE concentration, pH, and temperature. The S-peptide forms an unusually stable α-helix, which is known to be stabilized by TFE. The magnitude of the effect of charged groups on the peptide, manifested by the change in α-helix stability as a function of pH, was not altered significantly by either TFE concentration or temperature, indicating that the lower dielectric constant of TFE is not important in the stabilization of this α-helix. This suggests that the α-helix might be stabilized by many interactions in addition to the effects of charges. The titration curve of circular dichroism vs. TFE concentration appears to be cooperative at 0°C, but becomes progressively less cooperative at temperatures between 25 and 75°C. The properties of the TFE stabilization indicate that TFE might be a useful probe with which to measure the stability of marginally stable peptides and small proteins.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 218-229 
    ISSN: 0887-3585
    Keywords: colicin E1 ; site-directed mutagenesis ; ion channel ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Cleavage of colicin E1 molecules with a variety of proteases or with cyanogen bromide (CNBr) generates COOH-terminal fragments which have channel-forming activity similar to that of intact colicin in planar lipid bilayer membranes. The smallest channel-forming fragment obtained by CNBr cleavage of the wild-type molecule consists of the C-terminal 152 amino acids. By the use of oligonucleotide-directed mutagenesis, we have made nine mutants along this 152 amino acid peptide, in which an amino acid was replaced by methionine in order to create a new CNBr cleavage site. The smallest of the CNBr-cleaved C-terminal fragments with channel-forming activity, in planar bilayer membranes, was generated by cleavage at new Met position 428 and has 94 amino acids, whereas a 75 amino acid peptide produced by cleavage of a new Met at position 447 did not have channel activity. The NH2-terminus of the channel-forming domain of colicin E1 appears therfore to lie between residues 428 and 447. Since, however, the last six C-terminal residues of the colicin can be removed without changing activity, the number of amino acids necessary to form the channel is 88 or less. In addition, the unique Cys residue in colicin E1 was replaced by Gly, and nine mutants were then made with Cys placed at sequential locations along the peptide for eventual use as sulfhydryl attachment sites to determine the local environment of the replaced amino acid. In the course of making 21 mutants, eight charged residues have been replaced by uncharged Met or Cys without changing the biological activity of the intact molecule.It has been proposed previously that the conformation of the colicin E1 channel is a barrel formed from five or six α-helices, each having 20 amino acids spanning the membrane and two to four residues making the turn at the boundary of the membrane. Our finding that 88 amino acids can make an active channel, combined with recently reported stoichiometric evidence that the channel is a monomer excludes this model and adds significant constraints which can be used in building a molecular model of the channel.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 239-246 
    ISSN: 0887-3585
    Keywords: halobacteria ; photosensory receptor ; retinal ; slow-cycling rhodopsins ; sensory rhodopsins ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A second slow-cycling retinylidene protein, in addition to slow-cycling (sensory) rhodopsin (SR), can be bleached with hydroxylamine and regenerated with all-trans retinal in photosensory signaling Halobacterium halobium membranes. Flash photolysis shows this protein undergoes a photochemical reaction cycle characterized by photoconversion of its ground state (λmax 480 nm) to a species with λmax ≤ 360 nm, which thermally regenerates the 480-nm species with a t½ of 260 msec at 25°C, under conditions in which SR photocycles at 650 msec in the same membranes. Mutants characterized with respect to their phototaxis behavior are identified which contain SR and the 480-nm pigment, the latter ranging from undetectable to a concentration equal to that of SR. Receptor mutants lacking all phototaxis sensitivity lack both of the photochemically reactive proteins. The mutant properties contribute to an accumulation of behavioral and spectroscopic evidence that the 480-nm pigment is a second sensory photoreceptor in H. halobium. NaDodSO4-polyacrylamide gel electrophoresis of [3H]retinal-labeled membrane proteins from the mutants indicates SR and the 480-nm pigment contain distinct chromophoric polypeptides differing in their migration rates. The data implicate polypeptides of 25,000 Mr and 23,000 Mr as retinal-binding polypeptides of SR and the 480-nm protein, respectively.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 230-238 
    ISSN: 0887-3585
    Keywords: microcins ; peptide antibiotic ; protein processing ; HPLC ; protein secretion ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Microcin B17 is a low-molecular-weight protein that inhibits DNA replication in a number of enteric bacteria. It is produced by bacterial strains which harbor a 70-kilobase plasmid called pMccB17. Four plasmid genes (named mcbABCD) are required for its production. The product of the mcbA gene was identified by labelling minicells. The mcbA gene product was slightly larger when a mutation in any of the other three production genes was present. This indicates that these genes are involved in processing the primary mcbA product to yield the active molecule. The mcbA gene product predicted from the nucleotide sequence has 69 amino acids including 28 glycine residues. Microcin B17 was extracted from the cells by boiling in 100 mM acetic acid, 1 mM EDTA, and purified to homogeneity in a single step by high-performance liquid chromatography through a C18 column. The N-terminal amino acid sequence and amino acid composition demonstrated that mcbA is the structural gene for microcin B17. The active molecule is a processed product lacking the first 26 N-terminal residues. The 43 remaining residues include 26 glycines. While microcin B17 is an exported protein, the cleaved N-terminal peptide does not have the characteristic properties of a “signal sequence,” which suggests that it is secreted by a mechanism different from that used by most secreted proteins of E. coli.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 247-255 
    ISSN: 0887-3585
    Keywords: protein folding ; domain interactions ; fluorescence transfer ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This report describes the use of fluorescence energy transfer between an intrinsic energy donor (tryptophan 177) and two chemically added acceptors to study intermediates in the folding of the β2 subunit of E. coli tryptophan-synthase. Two early folding steps are thus identified and characterized. One is very rapid (its rate constant at 12°C is 0.02 sec-1) and corresponds to the folding of the N-terminal domain into a structure whose overall features approximate well those of the native domain. The second step is somewhat slower (its rate constant at 12°C is 0.008 sec-1) and involves a conformational rearrangement of the N-terminal domain brought about by the interactions between the N-and C-terminal domains within a monomeric β chain. This brings to five the number of intermediates which have been identified and ordered on the folding pathway of the dimeric β2 subunit.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 263-266 
    ISSN: 0887-3585
    Keywords: protein-DNA interaction ; overproducer clone ; sequence-specific recognition ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: HhaII restriction endonuclease purified from an overproducing recombinant E. coli clone has been cocrystallized with a heptanucleotide duplex, d-GGAGTCC:GGACTCC. The cocrystals are monoclonic and belong to the space group C2. The unit cell dimensions are a = 199.0±1.0 Å, b = 100.0±0.5 Å, c = 80.3±0.4 Å, and β = 101.0±1.0°. There appear to be two dimers per asymmetric unit and the crystals diffract to 4-Å resolution.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 256-262 
    ISSN: 0887-3585
    Keywords: FV fragment ; space filling hapten ; reconstitution ; scratched analysis ; equilibrium dialysis ; contact residues ; hypervariable loops ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: IgG Gar, a human myeloma protein that binds riboflavin with a high affinity, was used to derive variable region fragments from the heavy chain and the light chain. Riboflavin binding ability of the active site generated by V(H) and light chain and the active site generated by V(H) and V(L) was compared to riboflavin binding by the F(ab) fragment. The riboflavin binding ability of the F(ab) fragment is the same as the intact molecule, while the binding ability of the active site formed by V(H) and light chain is lowered by two to three orders of magnitude, indicating that the removal of C(H1) domain decreases the interaction between riboflavin and the amino acids that is important in tight binding of riboflavin. Removal of the third hypervariable region and the constant region domain from the light chain further lowers the binding constant by one order of magnitude. The results indicate that the V(H) and V(L) segments of IgG Gar can reconstitute a riboflavin binding site. The decrease in affinity probably reflects a decrease in the rigidity with which the hypervariable loops are held together to place the contact amino acid residues in optimal contact with the hapten.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 267-279 
    ISSN: 0887-3585
    Keywords: molecular model building ; energy minimization ; homology modeling ; site-specific mutagenesis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A procedure (coupled perturbation procedure, CPP) is introduced as a specific method for calculating the detailed three-dimensional structure of a protein molecule which has a nummber of amino-acid substitutions relative to some previously determined “parent” protein structure. The accuracy of the procedure is tested by calculating the conformation of a region of the human immunoglobulin fragment Fab Kol based on the analogous region of the human immunoglobulin fragment Fab New. Both structures have previously been determined crystallographically. The calculated model is accurate to the extent that both of the sequence differences in the region are modeled correctly and that conformational changes in a number of nearby residues are correctly identified. CPP is shown to give better results than other commonly used modeling procedures when applied to the same problem.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986) 
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. i 
    ISSN: 0887-3585
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 280-286 
    ISSN: 0887-3585
    Keywords: antibody affinity ; ELISA ; β-endorphin models ; melittin model ; amphiphilic α-helix ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Monoclonal antibodies against human apolipoprotein A-I (apoA-I) were generated by the hybridoma technique. Clone G-10 was selected on the basis of its highest titer. The affinity of this antibody toward a series of synthetic peptides differing in length, amino acid composition, and amphiphilicity was tested by using both the indirect and the competitive enzyme-linked immunosorbent techniques (ELISA). From these measurements we calculated dissociation constants of the complexes of the antibody with apoA-I bound to the surface of the microtiter plate, apoA-I in solution, and any of the several peptides in solution. The dissociation constant (Kd) of the immobilized apoA-I/anti-apoA-I-complex, Kd = 2 × 10-9 M, was significantly lower than that of the complex resulting from the interaction between anti-apoA-I and either apoA-I in solution or any of the several amphiphilic helical peptides in solution. Peptides devoid of amphiphilic secondary structure were inert. These data are consistent with the proposal that monoclonal G-10 recognizes in antigenic peptides an α-helical secondary structure of defined hydrophilic-lipophilic balance and comparatively less the specific amino acid side chains. We propose that the highest contribution to the free energy of binding (8 Kcal/mole) is derived from the docking of the helix to the antibody. It follows that in probing the specificity of a monoclonal antibody the conformation and the physical environment of the interacting antigen must be taken into account.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 287-301 
    ISSN: 0887-3585
    Keywords: primary sequence homology ; primary structure ; secondary structure ; quaternary structure ; gene cloning ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 302-311 
    ISSN: 0887-3585
    Keywords: mutant proteins ; protein stability ; operator binding ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: We have isolated 64 different missense mutations at 36 out of 53 residue positions in the Arc repressor of bacteriophage P22. Many of the mutant proteins with substitutions in the C-terminal 40 residues of Arc have reduced intracellular levels and probably have altered structures or stabilities. Mutations in the N-terminal ten residues of Arc cause large decreases in operator DNA binding affinity without affecting the ability of Arc to fold into a stable three-dimensional structure. We argue that these N-terminal residues are important for operator recognition but that they are not part of a conventional helix-turn-helix DNA binding structure. These results suggest that Arc may use a new mechanism for sequence specific DNA binding.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 312-325 
    ISSN: 0887-3585
    Keywords: membrane proteins ; nucleotide sequence ; evolution ; photosynthesis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The reaction center is a pigmentprotein complex that mediates the initial photochemical steps of photosynthesis. The amino-terminai sequences of the L, M, and H subunits and the nucleotide and derived amino acid sequences of the L and M structural genes from Rhodopseudomonas sphaeroides have previously been determined. We report here the sequence of the H subunit, completing the primary structure determination of the reaction center from R. sphaeroides. The nucleotide sequence of the gene encoding the H subunit was determined by the dideoxy method after subcloning fragments into single-stranded M13 phage vectors. This information was used to derive the amino acid sequence of the corresponding polypeptide. The termini of the primary structure of the H subunit were established by means of the amino and carboxy terminal sequences of the polypeptide. The data showed that hte H subunit is composed of 260 residues, corresponding to a molecular weight of 28,003. A molecular weight of 100,858 for the reaction center was calculated from the primary structures of the subunits and the cofactors. Examination of the genes encoding the reaction center shows that the codon usage is strongly bviased towards codons ending in G and C. Hydropathy analysis of the H subunit sequence reveals one stretch opf hydrophobic residues near the amino terminus; the L and M subunits contain five such stretches. From a comparison of the sequences of homologous proteins found in bacterial reaction centers and photosystem II of plants, an evolutionary tree was contructed. The analysis of evolutionary relationships showed that the L and M subunits of reaction centers and D1 and D2 proteins of photosystem II are descended from a common ancestor, and that the rate of change in these proteins was much higher in the first billion years after the divergence of the reaction center and photosystem II than in the subsequent billion years represented by the divergence of the species containing these proteins.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 42
    ISSN: 0887-3585
    Keywords: thermal stability ; protein engineering ; mutagenesis ; plate assay ; thermophilic enzymes ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A Procedure has been developed for the isolation and identification of mutants in the bacterial serine protease subtilisin that exhibit enhanced thermal stability. The cloned subtilisin BPN'gene from Bacillus amyloliquefaciens was treated with bisulfite, a chemical mutagen that deaminates cytosine to uracil in single-stranded DNA. Strains containing the cloned, mutagenized subtilisin gene which produced subtilisin with enhanced thermal stability were selected by a simple plate assay procedure which screens for esterase activity on nitrocellulose filters after preincubation at elevated temperatures. One thermostable subtilisin variant, designated 7150, has been fully characterized and found to differ from wild-type subtilisin by a single substitution of Ser for Asn at position 218. The 7150 enzyme was found to undergo thermal inactivation at onefourth the rate of the wild-type enzyme when incubated at elevated temperatures. Moreover, the midpoint in the thermally induced transition from the folded to unfolded state was found to be 2.4-3.9°C higher for 7150 as determined by differential scanning calorimetry under a variety of conditions. The refined, 1.8-Å crystal structures of the wild-type and 7150 subtilisin have been compared in detail, leading to the conclusion that slight improvements in hydrogen bond parameters in the vicinity of position 218 result in the enhanced thermal stability of 7150.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 43
    ISSN: 0887-3585
    Keywords: cellulases ; active sites ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Cellulomonas fimi produces an endoglucanase and an exoglucanase which bind strongly to cellulose. Each enzyme contains three distinct regions: a short sequence of about 20 amino acids containing only proline and threonine (the ProThr box); an irregular region, rich in hydroxyamino acids, of low charge density, and which is predicted to have little secondary structure; and an ordered region of higher charge density which contains a potential active site, and which is predicted to have secondary structure; and an ordered region of higher charge density which contains a potential active site, and which is predicted to have secondary structure. The Pro-Thr box is conserved almost perfectly in the two enzymes. The irregular regions are 50% conserved, and the conserved sequences include four Asn-Xaa-Ser/Thr sites. The ordered regions appear not to be conserved, but the potential active sites both have the sequence Glu-Xaa7-Asn-Xaa6-Thr; they occur at widely separated sites in the two regions. The order of the regions is reversed in the two enzymes: irregular-Pro-Thr box-ordered in the endoglucanase; ordered-Pro-Thr box irregular in the exoglucanase. The genes for the two enzymes appear to have arisen by shuffling of two conserved sequences and either one or two other sequences.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 44
    ISSN: 0887-3585
    Keywords: antibodies ; immunoglobulins ; conformation prediction ; energy minimazation ; random stranting conformations ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: We describe a method for predicting the conformations of loops in proteins and its application to four of the complementarity determining regions [CDRs] in the crystallographically determined structure of MCPC603. The method is based on the generation of a large number of randomly generated conformations for the backbone of the loop being studied, followed by either minimization or molecular dynamics followed by minimization starting from these random structures. The details of the algorithm for the generation of the loops are presented in the first paper in this series (Shenkin etal.[submitted]). The results of minimization and molecular dynamics applied to these loops is presented here. For the two shortest CDRs studied (H1 and L2, which are five and seven amino acids long), minimizations and dynamics simulations which ignore interactions of the loop amino acids beyond the carbon ture closely. This suggests that these loops fold independently of sequence variation. For the third CDR (L3, which is nine amino acids), those portions of the CDR near its base which are hydrogen bonded to framework are well replicated by our procedures, but the top of the loop shows singificant conformational variability. This variability persists when side chain interactions for the MCPC603 sequence are included. For a fourth CDR (H3, which is 11 amino acids long), new low-energy backbone conformations are found; however, only those which are close to the crystal are compatible with the sequence when side chain interactions are taken into account. Results from minimuzation and dynamics on single CDRs with all other CDRs removed are presented. These allow us to explore the extent to which individual CDR conformations are determined by interactions with framework only.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 370-375 
    ISSN: 0887-3585
    Keywords: enzyme structure ; disorder ; refinement ; high resolution ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The highly refined 1.26 Å structure (R = 0.15) of phosphate-free bovine pancreatic ribonuclease A was modeled with 13 residues having discrete multiple conformations of side chains. These residues are widely distributed over the protein surface, but only one of them, Lys 61, is involved in crystal packing interactions. The discrete conformers have no unusual torsion angles, and their interactions with the solvent and with other atoms of the protein are similar to those residues modeled with a single conformation. For three of the residues-Val 43, Asp 83, and Arg 85-two correlated conformations are found. The observed multiple conformations on the protein surfaces will be of significance in analyzing structure-function relationships and in performing protein engineering.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 46
    ISSN: 0887-3585
    Keywords: cDNA library ; disulphide bridges ; prosegment homology ; mRNA structure ; N-glycosylation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In order to characterize the zymogen of the milk-clotting enzyme from Rhizomucor miehei, we constructed a cDNA library on pBR327 in Escherichia coli. Aspartic proteinase-specific recombinants were isolated by colony hybridization to a specific oligonucleotide mixture, and the cDNA sequence corresponding to a precursor form of the enzyme was determined.The decuced amino sequence shows that this secreted fungal proteinase is synthesized as a precursor. The first 22 amino acid residues in this precursor constitute a typical signal peptide. The amino acid sequence of the following 47-amino-acid-long prosegment shows homology to the prosegments from both the extracellular and intracellular vertebrate aspartic proteinases, and to the prosegments from the yeast and Mucor pusillus aspartic proteinases as well. These observations suggest that all aspartic proteinases are synthesized with a prosegment and that this prosegment is essential for the correct folding of all the mature enzymes. The active Rhizomucor miehei enzyme consists of 361 amino acide residues with a total molecular weight of 38,701. Clusters of idendtities around the active site cleft support the assumption that these proteinasess have a common folding of their peptide chains. The disulphide bridges were localized in the fungal enzyme, and 2 N-glycosylation sites were identified.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 1 (1986), S. 376-384 
    ISSN: 0887-3585
    Keywords: ribonucleotide reductase ; unique N-terminal domain ; nucleotide binding site ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Herpes simplex virus type 1 (HSV-1) encodes a ribonucleotide reductase which comprises two polypeptides with sizes of 136,000 (RR1) and 38,000 mol. wt. (RR2). We have determined the entire DNA sequence specifying HSV-1 RR1 and have identified two adjacent open reading frames in varicella-zoster virus (VZV) which have homology to HSV RR1 and RR2; the predicted sizes for the VZV RR1 and RR2 polypeptides are 87,000 and 35,000 mol. wt. respectively. Amino acid comparisons with RR1 and RR2 polypeptides from other organisms indicate that HSV-1 RR1 contains a unique N-terminal domain which is absent from other RR1 polypeptides apart from HSV-2 RR1. These N-terminal amino acid sequences are poorly conserved between HSV-1 and HSV-2 in contrast to the remainder of the protein which shows greater than 90% homology. Polypeptide structural predictions suggest that the HSV-1 N-terminal domain may be separated into two regions, namely, a β-sheet structure followed by a nonstructured area. Across the remainder of RR1 and RR2, comparisons also reveal blocks of amino acids conserved between the different ribonucleotide reductases, and these may be important for enzyme activity. From predictions on the structure of these conserved blocks, we have proposed that the location of a substrate binding site within RR1 is centered on three conserved glycine residues in a region which is predicted to adopt a β-sheet/turn/α-helical structure;this approximates to the structure for ADP nucleotide binding folds. Finally, we propose that the promoters for the HSV and Eptein-Barr virus (EBV) RR2 transcripts have evolved by separate evolutionary routes.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 16-20 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method is described using fast protein liquid chromatography (FPLC) for the monitoring of protein formation during fermentation. The procedure consists of centrifugation to recover the cells, sonication of the cells, centrifugation to remove cell debris, and analysis of supernatant on a column of Mono Q (a strong anion exchanger). Analysis of peak areas provides quantitative determination of product concentration. Maintenance and life of the Mono Q column is discussed. We find that FPLC is a convenient method for measuring products in cell homogenates because it gives rapid, highly resolved separations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 21-28 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Biosorption of uranium and lead by lyophilized cells of Streptomyces longwoodensis was examined as a function of metal concentration, pH, cell concentration, and culture age. Cells harvested from the stationary growth phase exhibited an exceptionally high capacity for uranium (0.44 g U/g dry weight) at pH 5. Calculated values of the distribution coefficient and separation factor indicated a strong preference of the cell mass for uranyl ions over lead ions. The specific uranium uptake was similar for the cell wall and the cytoplasmic fraction. Uranium uptake was associated with an increase in hydrogen ion concentration, and phosphorus analysis of whole cells indicated a simple stoichiometric ratio between uranium uptake and phosphorus content. It is proposed that metal ions are bound to phosphodiester residues present both in the cell wall and cytoplasmic fractions. Based on this model, it was shown that uranium accumulation exhibits a maximum at pH 4.6 that is supported by experimental data from previous investigations.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 41-50 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Continuous cellulase production by Trichoderma viride QM 9123, immobilized in 6 mm diameter, spherical, stainless steel biomass support particles, has been achieved using a medium containing glucose as the main carbon source. Experiments were carried out in a 10-L spouted bed fermentor. In this type of reactor-recycled broth is used to create a jet at the base of a bed of particles, causing the particles to spout and circulate. During the circulation, particles pass through a region of high shear near the jet inlet. This effectively prevents a buildup of excess biomass and thus enables steady-state conditions to be achieved during continuous operation. Continuous production of cellulase was achieved at significantly higher yield and productivity than in conventional systems. At a dilution rate of 0.15 h-1 (nominal washout rate for freely suspended cells is 0.012 h-1), the yield of cellulase on glucose was 31% higher than that measured during batch operation, while the volumetric productivity (31.5 FPA U/L· h) was 53% greater than in the batch system. The specific cellulase productivity of the immobilized cells was more than 3 times that of freely suspended cells, showing that diffusional limitations can be beneficial. This offers significant opportunity for the further development of biomass support particles and associated bioreactors.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 64-72 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Urokinase was immobilized by entrapment to fibrocollagenous tubes in order to develop a small-caliber fibrinolytic vascular prosthesis. Several parameters associated with the immobilization process were studied in order to optimize bound urokinase activity and stability. A total of 37% of the absorbing enzyme was attached to the collagen tube and 38% of the attached enzyme retained esterolytic activity, under optimal conditions. In the crosslink step of the entrapment process, the glutaraldehyde concentration was varied from 0.01 to 5.00% (i.e., 0.01, 0.1, 1.0, 3.0, and 5.0%). Urokinase activity was optimized at a 1.0% glutaraldehyde crosslink concentration. Urokinase-bound fibrocollagenous tubes (UK-FCT) prepared at the above glutaraldehyde concentrations were tested for their activity with time. The UK-FCT's with 0.1, 1.0, and 3.0% glutaraldehyde retained constant activity for at least 75 h operation time. The UK-FCT's with 0.1, 1.0, and 3.0% glutaraldehyde retained constant activity for at least 75 h operation time. The UK-FCT's with 5.0 and 0.01% glutaraldehyde remained stable for the first 50 h operation time, but begandeactivating beyond 50 h. UK-FCT'S Crosslinked with 0.01, 0.1, 1.0, and 5.0% glutaraldehyde were recrosslinked with 0.02% glutaraldehyde for 24 h, after they have been operating for 50 h, and the effect of reexposing the crosslink agent on the stability of the UK-FCT's was studied. The results showed that 0.02% glutaraldehyde reexposure had no effect on 0.1, 1.0, and 5.0% glutaraldehyde crosslinked UK-FCT's but exerted an inhibitory effect on a 0.01% crosslink density UK-FCT. Several fibrocollagenous tubes were exposed to various glutaraldehyde concentrations prior to immobilizing urokinase. The subsequent immobilization process occurred under optimal conditions. The effect of the precrosslink step on the activity of the UK-FCT was studied. Results indicated that UK-FCT activity decreases as the precrosslink density increases. The UK-FCT's made under optimal conditions remained stable for at least 75 h operation time, corresponding to ca.1 year of storage time. Ex vivo exposure of UK-FCT's to whole canine blood did not affect catalytic activity. Implantation of a UK-FCT by carotid arterial interposition via an end-to-end anastomosis and subsequent excision after 60 days resulted in an enhanced esterolytic activity which decreased with time to a level close to preoperative levels.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 101-106 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 110-111 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 115-118 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 119-121 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: No Absract.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 129-132 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 29-40 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A separate role for water activity in the conversion of sugars to ethanol by two strains of yeast is identified. During fermentation of both single and mixed sugar substrates, the water activity was shown to remain constant during the logarithmic growth phase. This is despite the changes in concentration of substrates and product, the constancy reflecting the fact that the greater influence of ethanol on the solution activity is counterbalanced, in the early stages of the fermentation, by its low yield. The end of the log phase of growth coincides with the start of a period of gradually decreasing water activity. For the more ethanol-tolerant strain UQM66Y, growth was found to cease at a constant value of water activity while that for the less tolerant strain UQM70Y depended on both ethanol concentration and water activity. It is argued that water activity is a more appropriate variable than ethanol concentration for describing some of the nonspecific inhibitory effects apparent in ethanol fermentations. A straightforward method for the calculation of water activity during such fermentations based on the use of solution osmolality is presented.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 59
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Poly(maleic anhydride styrene) graft copolymers of cellulose, pectin polygalacturonic acid salt, calcium polygalacturonate, and starch were prepared and used to immobilize proteins. The cellulose grafts coupled quite appreciable quantities of acid phosphatase, glucose oxidase, and trypsin. However, the general retention of activity was somewhat disappointing. Further investigation with acid phosphatase showed that the amount of enzyme immobilized increased as the amount of anhydride in the graft copolymer increased but no such relationship existed for the enzymic activity. The cellulose graft copolymers were hydrolyzed and it appeared that the carboxyl group aided adsorption of the enzyme. Attempts to couple acid phosphatase using CMC through the free carboxyl groups, created by hydrolysis, gave only a small increase in the extent of protein coupling. However, the unhydrolyzed system gave a useful degree of immobilization of cells of Bacillus stearothermophilus, as did a poly(maleic anhydride/styrene)-cocellulose system. Attempts to improve the activity by using grafts based on other polysaccharide supports met with mixed success. Pectin products were soluble. Polygalacturonic acid products were partially soluble and extremely high levels of enzymic activity were obtained. This was probably due in part to the hydrophilic nature of the system, which also encouraged absorption of the enzyme. Attempts were made to reduce the solubility by using the calcium pectinate salt. Immobilization of acid phosphatase and trypsin resulted in inceased protein coupling but relatively poor activities were attained. A starch based system gave similar results. Calcium polygalacturonate was used to prepare an insoluble graft copolymeric system containing acrylonitrile-comaleic anhydride. The resulting gels gave excellent coupling with acid phosphatase which had a very good retention of activity.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 107-109 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 603-604 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 585-602 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A comprehensive review of the microbial kinetics, energetics, and substrate specificities of anaerobic waste-water treatment systems is presented with descriptions of three different state-of-the-art reactor configurations. Each of these reactor systems is intended to enrich different populations of anaerobic acidogens and methan-ogens as a result of design and operational strategies for control of hydrogen and volatile acids. Imposition of these strategies results in different substrate utilization patterns, conversion kinetics, and operational stabilities as are currently being demonstrated in laboratory-scale investigations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 167-175 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics in fed-batch cultures of acetone butanol fermentation by Clostridium acetobutylicum is compared on glucose, xylose, and mixtures of both sugars. The final conversion yield of sugars into solvents always increases with the sugar feeding rate. At low feeding rates, the sugar concentration in the medium becomes limiting, which results in a slower cellular growth, a slower metabolic transition from an acid to a solvent fermentation and, thus, a higher accumulation of acids. It is only at sufficiently high feeding rates that fed-batch fermentations yield kinetic results comparable to those of batch fermentations. With mixtures of glucose and xylose, because of a maintained low glucose level, both sugars are taken up at the same rate during a first fermentation period. An earlier accumulation of xylose when the fermentation becomes inhibited suggest that xylose utilization is inhibited when the catabolic flux of glucose alone can satisfy the metabolic activity of the cell. Kinetic results with batch and fed-batch fermentations indicate several important features of the regulation of C. acetobutylicum metabolism: an early inhibition by the produced acids; an initiation of solvent formation between 4 and 6 g/L acetic and butyric acid depending on the metabolic activity of the cell; a metabolic transition from acids to solvents production at a rate closely related to the rate of sugar uptake; during solvent production, a reassimilation of acids above a minimal rate of sugar consumption of 0.2 h-1; a final inhibition of the fermentation at a total butanol and acids concentration of ca. 20 g/L.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 631-645 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The feasibility of applying an adaptive control technique to a fermentation process is investigated. The nonlinear, time-variant parameters of a fermentation process were estimated on-line as a series of linearized describing matrices. The matrices were used to update a suboptimal feedback law which controlled the process in real time over the linear region. Experiments were performed on a small-scale fully instrumented fermenter with the online, real-time adaptive control package. Results are presented for both single- and multivariable control, and indicate successful control of yeast cell growth.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 659-662 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A nitrate control system has been devised for the maintenance of stable nitrate concentrations throughout fed-batch fermentations of Corynebacterium glutamicum. The feedback control system was based on the use of a nitrate-ion-selective electrode to directly monitor the nitrate levels in the fermentor and an automatic controller to activate a nitrate feed pump. The electrode which was used for controlling the nitrate level was stable through-out the fermentation period. The apparent maximum specific growth rate, biomass production, protein production, biomass yields on glucose and nitrate, and amino acid production were all optimal at approximately 50mM nitrate.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 646-658 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Growth of a hybridoma culture, along with production of monoclonal antibody, was demonstrated over extended periods in polysulfone hollow fiber membrane modules. The molecular weight cutoffs of the membranes were 70,000, 50,000, and 100,000 daltons. The hybridoma cell line, designated 65/26, produced IgG (2b/κ) directed at mouse thymus cell surface antigen, TL.1. Cell growth occurred in the shell space of the reactor, using supplemented RPMI 1640 (20% fetal bovine serum) supplied from a separate reservoir vessel through the hollow fiber lumen. The reservoir contained 125 mL media, which was changed every 4 days. Concentrations of immunoglobulin were determined by an enzyme immunoassay (using protein A and alkaline phosphatase-labeled antibody conjugate). For the 10K, 50K, and 100K hollow fiber membrane modules, the maximum IgG concentrations detected in the 2.5-mL shell space were 47.5-80, 510, and 740 μg/mL, respectively. In the 125-mL reservoir for the 100K hollow fiber membrane module, the IgG concentration was measured at 260 μg/mL These values compare with an IgG concentration of 1 μg/mL when grown in a standard tissue culture flask and 3.2-7.6 μg/mL when grown in 100 ml media in a spinner flask. In addition, 10K and 50K hollow fiber membrane modules were run in a mode that decreased the fetal bovine serum supplement with time. Differences between these systems suggest that it is possible to obtain high IgG accumulation rates, both during and after the exponential growth phase of the hybridoma population.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1056-1063 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Isoelectric fractionation of the two major proteins of soy is characterized. Fractions are acid precipitated and cen-trifugally collected at pH 6.0 (glycinin) and pH 4.8 (β-conglycinin). Two extremes in the speed of acid addition (rapid, with no mixing, and slow, via acid dialysis, with complete mixing) are compared to determine their effects on the properties of the precipitate. Total protein yield, fraction composition, and aggregate microstructure do not depend significantly on the method of acid addition. Particle size distribution and hindered settling behavior do differ and are explained using a model of aggregate strength. The rapid acid addition produces larger primary particles, because of higher supersaturation, and yields larger aggregates, because of higher interparticle potential and stronger aggregates. Further aggregation in low-shear hindered settling is faster for the slowly precipitated aggregate because few of these bonding sites could survive the high-shear precipitator, whereas more can contribute to aggregation during hindered settling.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1080-1085 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dehydrogenase activity assay of activated sludge using the redox dye 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride (INT) was investigated. INT-dehydrogenase activity (INT-DHA) was directly proportional to INT dosage and inversely proportional to bio-mass concentration over limited ranges. INT dosages exceeding 2.5m/M were toxic to dilute activated sludge suspensions. INT-DHA was greatest near pH 9, whereas the peak oxygen uptake rate (OUR) occurred at pH 8. Both INT-DHA and OUR varied inversely with sludge age, but INT-DHA was the more sensitive of the two parameters to this variable. Consistently good and highly significant correlations between INT-DHA and OUR of chlorine stressed activated sludge were found at sludge ages ranging 2.2-7.0 days.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1127-1137 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two microorganisms, E. coli and S. cerevisiae, competing for glucose were maintained in a stable cycle of coexistence by alternating the growth advantage between the two organisms by oscillating the pH in a Chemostat. Pure culture experiments found S. cerevisiae to be insensitive to pH between 5 and 4.3 with a maximum specific growth rate (μmax) of 0.4/hr; while μmax of E. coli decreased from 0.6 h-1 at pH 5 to 0.1 h-1 at pH 4.3. Steady-state and cross-inoculation chemostat runs at a dilution rate of 0.17 h-1 confirmed the expectation that the mixed culture system is unstable at constant pH with E. coli dominating at pH 5 and S. cerevisiae dominating at pH 4.3. Three pH oscillation experiments were performed at D =0.17 h-1 with 1 g per liter glucose feed. The 16 h/16 h cycle was stable for six periods with a stable alternating cycle of E. coli and S. cerevisiae being quickly established. A 18 h pH 5/14 h pH 4.3 cycle was found to be stable with smaller yeast concentrations. A 6 h/6 h cycle was found unstable with yeast washout. Simulation results were compared with these runs and were used to predict the onset of instability. Oscillations of pH can force stable persistence of a competing mixed culture that is otherwise unstable. Thus, varying conditions are experimentally demonstrated to be one explanation for competitive coexistence.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 256-268 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of chemical modification on the initial specific activity, residual activity, and deactivation kinetics of various enzymes is analyzed using a series mechanism. This straightforward multistate sequential model presented is consistent with the enzyme deactivation data obtained from different fields. The enzymes are placed in five different categories depending on the effect of chemical modification on initial specific activity and residual activity or stability. Wherever possible, structure-function relationships are described for the enzymes in the different categories. The categorization provides one avenue that leads to further physical insights into enzyme deactivation processes and into the enzyme structure itself.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 283-287 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 288-293 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Wheat straw has been hydrolized with sulfuric acid at 34 and 90°C. The treatment at 90°C yields complete solubilization of hemicellulose to xylose and arabinose without significant amounts of furfural. The influence of acid concentration was studied and the kinetics of the acid-catalyzed hydrolysis has been modeled suggesting a two-consecutive reactions mechanism. This model is useful to explain the different behavior of the concentration of the two main sugars produced. The enhanced cellulose accessibility to enzymatic attack is also reported.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 269-282 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Within the framework of a program aiming to improve the existing extractive recovery technology of fermentation products, the state of the art is critically reviewed. The acids under consideration are propionic, lactic, pyruvic, succinic, fumaric, maleic, malic, itaconic, tartaric, citric, and isocitric, all obtained by the aerobic fermentation of glucose via the glycolytic pathway and glyoxylate bypass. With no exception, it is the undissociated monomeric acid that is extracted into carbon-bonded and phosphorus-bonded oxygen donor extractants. In the organic phase, the acids are usually dimerized. The extractive transfer process obeys the Nernst law, and the measured partition coefficients range from about 0.003 for aliphatic hydrocarbons to about 2 to 3 for aliphatic alcohols and ketones to about 10 or more for organophosphates. Equally high distribution ratios are measured when long-chain tertiary amines are employed as extractants, forming bulky salts preferentially soluble in the organic phase.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 678-683 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Batch and continuous fermentations with Clostridium thermoaceticum (ATCC 39073) using automatic pH control were conducted. The value of μmax obtained from batch fermentation was about 0.14 h-1; acetate yield, which was both growth and non-growth associated, was about 2 mole of acetic acid/mole of glucose, compared with a theoretical maximum value of 3. This low yield, compared with literature data, may be explained by glucose loss through a combination of degradation routes. Continuous fermentation could be sustained for 1600 h or more without contamination problems. Continuous fermentation at high dilution rates indicates that μmax may be well above 0.17 h-1 when fresh feed medium is used. Acetate yields in continuous fermentation were about 77% of theoretical or 2.3 mole of acetic acid/mole of glucose.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 75
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Both the forward and backward reactions of xylose isomerase (Sweetzyme Q) with xylose and glucose as substrates have been studied in terms of kinetics and thermodynamics. The relationship between the two reactions can thus be determined. Much attention has been given to the reaction with xylose as substrate. The optimal conditions of the xylose reaction in terms of pH, buffer, metal ions, substrate concentration, temperature, and ionic strength have been determined. These findings did not differ much from those reported for the glucose reaction. Equilibrium constants for the aldose to ketose conversion were more favorable in the case of glucose. The results obtained with continuous isomerization of xylose in columns packed with either Sweetzyme Q or Taka-Sweet were very similar to those obtained from batch isomerization processes. Particle size had a definite effect on reaction rate, which indicates that diffusion limitations do occur with the immobilized enzyme particles. Heat stability of Sweetzyme Q was good with t1/2 of 118, 248, and 1200 h at 70, 55, and 40°C, respectively. A novel method for the separation of xylose-xylulose mixtures with water as eluant on a specially prepared Dowex 1 × 8 column was developed. This technique has the capability of producing pure xylulose for industrial or research applications. A writ for a patent regarding this technique is at present prepared.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 76
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 711-717 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Alcoholic fermentations of starch hydrolysate by two different yeast strains, Saccharomyces cerevisiae(var. Vinal) and Saccharomyces oviformis(IMAP 383), have been studied in batch runs. In order to evaluate the different inhibition phenomena due to both substrate and product, a new kinetic equation is suggested.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 77
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 700-710 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Continuous cultures of Saccharomyces cerevisiae are known to exhibit oscillatory behavior in the oxidative region. Important findings of a series of experiments conducted to identify the causes for initiation of and the means for elimination of oscillations in these cultures are reported in this paper. These oscillations are seen to be connected to the growth kinetics of the microorganism and are induced at very low glucose concentrations and at dissolved oxygen (DO) levels that are neither high nor low (DO values between 20 and 78% air saturation at a dilution rate of 0.2 h-1 and pH of 5.5 at 30°C). The oscillatory behavior is encountered over a range of dilution rates (0.09-0.25 h-1 at 30°C for pH = 5.5 and DO = 50% air saturation). The oscillations can be eliminated by raising the DO level above a critical value or by lowering the DO level below a critical value.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 728-735 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A comparison of the relative performance of production techniques using coenzyme or cofactor electrochemical regeneration demonstrates the superiority of those processes in which the enzymatic reaction and the regeneration are conducted in the same reactor as opposed to those in which the reaction and regeneration are separated. For the former type of reactor, a method of calculation is proposed. This method is based on the solution of equations which describe the phenomena in modules representing three areas: the surface of the electrode, a layer where occur simultaneously the transport of material and the enzymatic reaction, and the bulk of the solution. This method is suggested for three types of reactor: those in which an enzyme solution is held close to an electrode by a semipermeable membrane, those in which an enzyme-charged membrane is in contact with an electrode, and those in which the enzyme is in solution in the vessel into which the electrode is dipped.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 79
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 718-727 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The development of granular sludge in thermophilic (55°C) upflow anaerobic sludge blanket reactors was investigated. Acetate and a mixture of acetate and butyrate were used as substrates, serving as models for acidified waste-waters. Granular sludge with either Methanothrix or Methanosarcina as the predominant acetate utilizing methanogen was cultivated by allowing the loading rate to increase whenever the acetate concentration in the effluent dropped below 200 and 700 mg COD/L, respectively. The highest methane generation rates, up to 162 kg CH4-COD/m3 day, or 2.53 mole CH4/L day, were achieved at hydraulic retention times down to 21 min, with granules consisting of Methanothrix. The formation of Methanothrix granules did not depend on the type of seed material, nor on the addition of inert support particles. The growth of granules proceeded rapidly with adapted seed material, even when the reactors were inoculated with low concentrations. With mesophilic seed materials growth of granules took much longer. Thermophilic Methanothrix granules strongly resemble mesophilic granules of the “filamentous” type. Some factors governing the thermophilic granulation process are discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 741-746 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 736-740 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bovine trypsin was crosslinked to human serum albumin (HSA) with glutaraldehyde to form soluble and insoluble copolymers. The physical and kinetic properties of trypsin and trypsin-HSA polymers were compared. Trypsin was heat labile, retaining only 24% of its enzymic activity after heating for 5 min at 60°C. In contrast, under the same condition both the soluble and insoluble trypsin-HSA polymers showed enhanced resistance to heat in-activation, retaining 81 and 100% of their original activities, respectively. The trypsin-HSA polymers also showed shifts in pH optima, an increase in activation energy, and a broadening of their pH stability profiles.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1277-1285 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A general model of enzyme deactivations involving unimolecular processes is introduced. For most mechanisms of this type, the parameters of the general model can be expressed in terms of actual physical parameters. The number of physical parameters that can be determined from the deactivation data cannot exceed the number of independent constants in the general model. When there is an excess of physical parameters, then some parameters must be determined from independent methods of analysis. If this is not possible, then some parameters must be left as lumped parameters or global parameters. The general form of the model can be useful in determining the number of independent, potentially active forms of the enzyme present during deactivation. Some exceptions to the general model are due to higher-order processes such as dissociation, autolysis, and biological contamination.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 756-760 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 85
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 761-763 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 764-767 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 769-784 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The morphology of yeast cells as it is affected by the glycosidic linkages of constituent glucan was studied. Four different strains of Saccharomyces cerevisiae were studied. A cell wall matrix particle representing the intact original morphology and composed entirely of β-glucan was prepared. Using prepared cell wall glucan particles, the morphology and cell wall matrix structure were examined. Genetic modification of the cell wall structure during growth results in the alteration of the shape and hydrodnamic volume of the intact cell wall particles. The shape and hydrodynamic volume of the cell wall particles can also be modified by in vitro chemical and enzymatic treatment. The shape factor and hydrodynamic volume of the whole glucan cell wall matrix particles were evaluated quantitatively using a rheological analysis. An increased degree of β(1 → 6) cross-linking in the cell wall matrix induces a nearly 2-fold increase in the shape factor and a 10-fold increase in the compression modulus of the glucan particles. The disruption of β(1 → 6) glycosidic cross-linking causes the particles to swell by up to 18% of their original volume. This was used as a strategy to isolate a yeast mutant with a high β(1 → 6) glycosidic content in the cell wall glucan.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1310-1317 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two instruments were developed to mechanize the handling of anaerobic microorganisms for microbial mutant isolation. The instruments automatically dispense liquid or agar medium to large and small 96-well platesand petridishes. Protocols were developed for inoculating different microorganisms, and calibration curves of number of areas or wells inoculated versus cell concentration were prepared for bacteria, yeast and fungi (spores). Experiments with yeast auxotrophic mutants and fungal spores showed that microbe inoculation follows Poisson statistics in distributing a single microorganism per inoculation point. The isolation and identification of Yarrowia lipolytica auxotrophic, morphological, and temperature-sensitive or tolerant mutants demonstrated the use of the instruments for microbial screening.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 90
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The problem of dilute solvent concentration in butanol-acetone fermentations can be solved by using reverse osmosis to dewater the fermentation liquor. Polyamide membranes have a potential application in a butanol-acetone fermentation and exhibited rejection rates as high as 98%. Optimum rejection of butanol in the fermentation liquor occurred at recoveries of 20-45%. Flux ranged from 0.05 to 0.6 L m-2 min-1.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 792-801 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Material balances for pentosan, lignin, and hexosan, during steam-explosion pretreatment of aspenwood, showed almost quantitative recovery of cellulose in the water-insoluble fraction. Dilute acid impregnation resulted in more selective hydrolysis of pentosan relative to undesirable pyrolysis, and gave a more accessible substrate for enzymatic hydrolysis. Thermocouple probes, located inside simulated aspenwood chips heated in 240°C-saturated steam, showed rapid heating of air-dry wood, whereas green or impregnated wood heated slowly. Small chips, 3.2 mm in the fiber direction, whether green or airdry gave approximately equal rates of pentosan destruction and solubilization, and similar yields of glucose and of total reducing sugars on enzymatic hydrolysis with Trichoderma harzianum. Partial pyrolysis, destroying one third of the pentosan of aspenwood at atmospheric pressure by dry steam at 276°C, gave little increase in yield of reducing sugars on enzymatic hydrolysis. Treatment with saturated steam at 240°C gave essentially the same yields of glucose and of total reducing sugars, and the same yields of butanediol and ethanol on fermentation with Klebsiella pneumoniae, whether or not 80% of the steam was bled off before explosion and even if the chips remained intact, showing that explosion was unnecessary.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 811-817 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Removal and modification of southern red oak hemicelluloses and lignin in a 0.05%(w/v) sulfuric acid hydrolysis were investigated. The hydrolysis profile was to raise the reaction from room temperature to 150°C for in 38 min and to extend the hydrolysis at 150°C for 1 h. At the end of the hydrolysis, 25.5% of red oak components were dissolved, of which 58% was xylose and 17% lignin. As the hydrolysis proceeded from room temperature to 150°C, a part of red oak xylan was removed to yield an oligomer fraction having maximal yield and average molecular weight of 3460 at 150°C. This fraction and the bulk xylan extracted during the first 30 min at 150°C were further degraded to give a lower molecular weight oligomer fraction, of which the yield and average molecular weight (2610) were highest at the end of the bulk removal of xylan. Red oak lignin, syringyl and guaiacyl units in particular, was increasingly removed with the progress of the hydrolysis. Lignin derivatives and a part of red oak extractives soluble in the hydrolysate were identified.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 818-823 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article concerns the development of a simple yet effective procedure for optimizing the design of a reactor system employing CSTRs in series. The basic approach used in this work was to translate the problem of reactor design to a mathematical programming model. The resulting model was then solved by dynamic programming. The procedure was tested on an IBM 3033 computer and an IBM PC-compatible machine, the CORONA PC-II microcomputer. The results of this study indicate that the optimization procedure developed is very effective.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1742-1752 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mixed culture of Saccharomyces cerevisiae and Escherichia coli was established in a stable coexistence steady state in a chemostat under constant operating conditions. The species competed for glucose, the growth-limiting resource, and produced acetate and ethanol. The acetic acid was shown to be very inhibitory to E. coli in pure culture at pH 5 while ethanol inhibition was only marginal. No significant inhibition of S. cerevisiae growth was observed by either acetate or ethanol. Pure culture parameters were measured and used in the analysis. Linearized stability analysis for the case when both organisms produce the inhibitor showed that a transition through three stable outcomes was possible as the feed concentration is lowered. Experimental studies verified these predictions, and successive transitions from a yeast growth steady state, to a coexistence steady state, and to an E. coli growth steady state were obtained by lowering the glucose concentration in the feed from 10 to 5 to 2.5 g/L, respectively. This dynamic behavior is distinct from the outcomes of other competition-inhibition combinations and experimentally demonstrates for the first time that coexistence is possible due to substrate competition and product inhibition.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 95
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The utilization of mixtures of methanol (C1) and glucose (C6) of different composition by the methylotrophic yeast Hansenula polymorpha was studied in carbon-limited chemostat culture. For all mixtures tested a similar utilization pattern was observed: At low dilution rates both carbon sources were utilized simultaneously, but at high dilution rates the cells used glucose only and the unutilized methanol accumulated in the culture medium. When grown with C1 only, the cells exhibited a critical dilution rate Dc(C1) of 0.19 h-1, but when C1-C6 mixtures were used as the carbon and energy substrate, the yeast was able to completely utilize C1 at dilution rates considerably higher than Dc(C1). The dilution rate at which the transition from C1-C6 growth to C6 growth occurred (Dt) was strictly dependent on the composition of the C1-C6 mixture in the feed, and Dt increased with decreasing proportions of C1 in the mixture. During mixed substrate growth the formation of biomass from the two substrates was additive. The results reported indicate that the utilization of C1-C6 mixtures and hence Dt in H. polymorpha are subject to two different regulatory regimes. When the cells were growing with C1-C6 mixtures containing more than 60% C1, the transition form C1-C6 to C6 growth was most probably influenced by the maximum C1 oxidizing capacity of the cells, whereas for growth with mixtures containing less than 40% C1, a growth rate of 0.28-0.30 h-1 seemed to be the limiting barrier for the simultaneous utilization of the components of the binary carbon and energy substrate mixture.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1769-1773 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A relatively simple and inexpensive anaerobic calorimeter was designed and evaluated by using a Hy-Cal Engineering BI-7 bidirectional heat-flux sensor to measure heat output from magnetically stirred I-L flask fermentations. The production of ethanol and cumulative heat output by Zymomonas mobilis were both linearly proportional to glucose concentrations up to 160 g/L.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1774-1779 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The irradiation with visible light of a photosensitizer dye like methylene blue was used to regenerate by electron transfer the oxidized form of a pyridine nucleotide coenzyme (NAD+). The process has been studied on a common enzymatic reaction: ethanol oxidation by alcohol-NAD+ oxidoreductase immobilized on polyacrylamide gel or porous glass balls. In the experimental conditions used, the initial NAD+ recycling rates were 2.33 × 104 cycles/h (polyacrylamide) and 3 × 104 cycles/h (glass balls). A total number of 49.5 × 104 cycles was obtained for 13 runs of 2 h. The enzyme immobilization strongly increased its stability: after 28 days at 20°C, the residual activity was 25% of the initial value.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1761-1768 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The production of ethanol from starch by a coimmobilized mixed culture system of aerobic and anaerobic microorganisms in Ca-alginate gel beads was investigated. The mold Aspergillus awamori was used as an aerobic amylolytic microorganism and an anaerobic bacterium, Zymomonas mobilis, as an ethanol producer. By controlling the mixing ratio of the microorganisms in the inoculum size, a desirable coimmobilized mixed culture system, in which the aerobic mycelia grew on and near the oxygen-rich surface of the gel beads while the anaerobic bacterial cells mainly grew in the oxygen-deficient central part of the gel beads, was naturally established under the aerobic culture conditions, and ethanol could be directly produced from starch by the system. The ethanol productivity by the system in flask culture was particularly affected by the shear stress (dependent on the shaking speed) which controlled the mycelial growth on the surface of the gel beads. Under optimum culture conditions in the flask culture, the glucose produced was instantly consumed, and was not observed in the culture broth; the final concentration of ethanol produced from 100 g/L starch was 25 g/L and the yield coefficient for ethanol, Ypls, was 0.38. The ethanol productivity by the coimmobilized mixed culture system was compared with those by other various culture systems and the advantages of the system were clarified.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1780-1793 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The modification and principle of a novel heat flux calorimeter for the in situ, on-line measurement of the heat generated during microbial growth is described. Data concerning the physical characterization of the calorimeter as a fermentor, including stability and sensitivity of the heat signal, are presented. The calorimeter has been successfully applied to the study of the aerobic batch culture of Escherichia coli W on glucose under carbon and nitrogen limitation. A direct correlation between growth and heat evolution was obtained. Quantitative analysis of the data suggests that the new calorimetric technique could be used for monitoring growth and specific metabolic events, for convenient medium optimization, and as a basis for a novel fermentation process control system.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1801-1808 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A predictive model was developed to estimate the dewatering characteristics of waste-activated sludges. This model utilizes the COD-nitrogen ratio of the wastewater and the organic loading rate of the process to predict sludge filterability in terms of specific resistance. A completely mixed, continuous flow secondary treatment process with solids recycle was used for the cultivation of activated sludges. The sludge wasted from this process was used in Buchner funnel specific resistance determinations. The basic concepts involved in the development of the model were supported by sludge carbohydrate, protein, and surface charge data.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...