bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quiet please, do not disturb: a hypothesis of embryo metabolism and viability
Authors: Leese Henry J. 
Published: September 2002

AbstractThis review uses nutritional markers of normal and impaired development to address the question; what makes a viable mammalian preimplantation embryo? Resolution of this question is important to ensure the long‐term safety of embryo‐based biotechnologies in man and domestic animals, the optimisation of embryo production and culture conditions and the development of methods to select viable embryos for replacement. After considering the nutrition of embryos and somatic cells, and the phenomenon of caloric restriction, it is concluded that preimplantation embryo survival is best served by a relatively low level of metabolism; a situation achieved by reducing the concentrations of nutrients in culture media and encouraging the use endogenous resources. BioEssays 24:845–849, 2002. © 2002 Wiley Periodicals, Inc.
Molecular control of neuronal migration
Authors: Park Hwan Tae , Wu Jane , Rao Yi 
Published: September 2002

AbstractOur understanding of neuronal migration has been advanced by multidisciplinary approaches. At the cellular level, tangential and radial modes of neuronal migration contribute to different populations of neurons and have differential dependence on glial cells. At the molecular level, extracellular guidance cues have been identified and intracellular signal transduction pathways are beginning to be revealed. Interestingly, mechanisms guiding axon projection and neuronal migration appear to be conserved with those for chemotactic leukocytes. BioEssays 24:821–827, 2002. © 2002 Wiley Periodicals, Inc.
The modulator is a constitutive enhancer of a developmentally regulated sea urchin histone H2A gene
Authors: Spinelli Giovanni , Birnstiel Max L. 
Published: September 2002

AbstractGoing back to the late 1970s and early 1980s, we trace the Xenopus oocyte microinjection experiments that led to the emergence of the concept of “modulator”. The finding that the modulator could transactivate transcription from far upstream and in either orientation suggested that a new genetic element, different from the classical prokaryotic promoter sequences, had been discovered. This particular enhancer transactivates transcription of the sea urchin early (α) histone H2A gene which is regulated in early sea urchin development. We summarise the data from sea urchin microinjection experiments that confirm and extend the results obtained with Xenopus oocytes. We conclude that the H2A enhancer is bipartite, is located approx. 100 bp upstream of the TATAAATA box in the H2A gene of two sea urchin species and enhances transcription when placed at a position far upstream or far downstream of the gene unless an insulator intervenes between enhancer and promoter. Evidence from microinjection experiments with sea urchin embryos suggests that the developmental control of H2A expression resides not with the enhancer, which is constitutively active, but with a striking chromatin structure with two positioned nucleosomes near the 3′ end of the gene. Within this structure, there is an insulator element. BioEssays 24:850–857, 2002. © 2002 Wiley Periodicals, Inc.
Epithelial barrier function: assembly and structural features of the cornified cell envelope
Authors: Kalinin Andrey E. , Kajava Andrey V. , Steinert Peter M. 
Published: September 2002

AbstractTerminally differentiating stratified squamous epithelial cells assemble a specialized protective barrier structure on their periphery termed the cornified cell envelope (CE). It is composed of numerous structural proteins that become cross‐linked by several transglutaminase enzymes into an insoluble macromolecular assembly. Several proteins are involved in the initial stages of CE assembly, but only certain proteins from a choice of more than 20 different proteins are used in the final stages of CE reinforcement, apparently to meet tissue‐specific requirements. In addition, a variable selection of proteins may be upregulated in response to genetic defects of one of the CE proteins or tissue injury, in an effort to maintain an effective barrier. Additionally, in the epidermis and hair fiber cuticle, a layer of lipids is covalently attached to the proteins, which provides essential water barrier properties. Here we describe our current understanding of CE structure, a possible mechanism of its assembly, and various disorders that cause a defective barrier. BioEssays 24:789–800, 2002. Published 2002 Wiley Periodicals, Inc.
Functional evolution of Hox proteins in arthropods
Authors: Vervoort Michel 
Published: September 2002

AbstractIt is presumed that the evolution of morphological diversity in animals and plants is driven by changes in the developmental processes that govern morphology, hence basically by changes in the function and/or expression of a defined set of genes that control these processes. A large body of evidence has suggested that changes in developmental gene regulation are the predominant mechanisms that sustain morphological evolution, being much more important than the evolution of the primary sequences and functions of proteins. Recent reports1, 2 challenge this idea by highlighting functional evolution of Hox proteins during the evolutionary history of arthropods. BioEssays 24:775–779, 2002. © 2002 Wiley Periodicals, Inc.
When machines get stuck—obstructed RNA polymerase II: displacement, degradation or suicide
Authors: van den Boom Vincent , Jaspers Nicolaas G.J. , Vermeulen Wim 
Published: September 2002

AbstractThe severe hereditary progeroid disorder Cockayne syndrome is a consequence of a defective transcription‐coupled repair (TCR) pathway. This special mode of DNA repair aids a RNA polymerase that is stalled by a DNA lesion in the template and ensures efficient DNA repair to permit resumption of transcription and prevent cell death. Although some key players in TCR, such as the Cockayne syndrome A (CSA) and B (CSB) proteins have been identified, the exact molecular mechanism still remains illusive. A recent report provides new unexpected insights into TCR in yeast.1 The identification and characterisation of a novel protein co‐purifying with the yeast homologue of CSB (Rad26) imposes reassessment of our current understanding of TCR in yeast. What about humans? BioEssays 24:780–784, 2002. © 2002 Wiley Periodicals, Inc.
Circular dichroism spectra of DNA quadruplexes [d(G5T5)]4 as formed with G4 and T4 tetrads and [d(G5T5) · d(A5C5)]2 as formed with Watson–Crick‐like (G‐C)2 and (T‐A)2 tetrads
Authors: Ito Hirotoshi , Tanaka Satoshi , Miyasaka Masaru 
Published: September 2002

AbstractWe utilize electrophoresis and find that a thermally treated equimolar mixture of the oligonucleotide d(G5T5) and its complementary oligonucleotide d(A5C5) exhibits either two bands or a single band in one lane, depending on the conditions of the incubation solutions. The thermally treated d(G5T5) solution loaded in a different lane exhibits a single band of the parallel quadruplex [d(G5T5)]4, which is composed of homocyclic hydrogen‐bonded G4 and T4 tetrads previously proposed. For the thermally treated equimolar mixture of d(G5T5) and d(A5C5), the fast band is assigned to a Watson–Crick d(G5T5) · d(A5C5) duplex, so that the slow band with the same low mobility as that of [d(G5T5)]4 may be assigned to either [d(G5T5)]4 itself or a [d(G5T5) · d(A5C5)]2 quadruplex. If the latter compound is true, this may be the antiparallel quadruplex composed of the heterocyclic hydrogen‐bonded G‐C‐G‐C and T‐A‐T‐A tetrads proposed previously. After removing these three bands for the duplex and two kinds of hypothetical quadruplexes, we electrophoretically elute the corresponding compounds in the same electrophoresis buffer using an electroeluter. The eluted compounds are ascertained to be stable by electrophoresis. The circular dichroism (CD) and UV absorption spectra measured for the three isolated compounds are found to be clearly different. For the electrophoretic elution of the hypothetical [d(G5T5)]4 quadruplex, the result of the molecularity of n = 4 obtained from the CD melting curve analysis provides further support for the formation of the parallel [d(G5T5)]4 quadruplex already proposed. For the thermally treated equimolar mixture of d(G5T5) and d(C5A5), the fast band with a molecularity of n = 2 corresponds to the Watson–Crick duplex, d(G5T5) · d(A5C5). The slow band with a molecularity of n = 4 indicates the antiparallel quadruplex [d(G5T5) · d(A5C5)]2, whose observed CD and UV spectra are different from those of [d(G5T5)]4. By electrophoresis, after reannealing the eluted compound [d(G5T5) · d(A5C5)]2, a distinct photograph showing the band splitting of this quadruplex band into the lower duplex and upper quadruplex bands is not possible; but by a transilluminator, we occasionally observe this band splitting with the naked eye. The linear response polarizability tensor calculations for the thus determined structures of the [d(G5T5)]4 quadruplex, the McGavin‐like [d(G5T5) · d(A5C5)]2 quadruplex, and the Watson–Crick d(G5T5) · d(A5C5) duplex are found to qualitatively predict the observed CD and UV spectra. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 65: 61–80, 2002
Surface fluorescence resonance energy transfer studies on interfacial adsorption of Thermomyces (humicola) lanuginosa lipase, using monomolecular films of cis‐parinaric acid
Authors: Yapoudjian S. , Ivanova M. , Douchet I. , Zénatti A. , Sentis M. , Marine W. , Svendsen A. , Verger R. 
Published: September 2002

AbstractThe fluorescence resonance energy transfer (FRET) technique was adapted to study the process whereby lipase is adsorbed to monomolecular lipid films spread at the air–water interface. When cis‐parinaric acid (cis‐PnA) was spread over an aqueous subphase before the injection of sodium taurodeoxycholate (NaTDC) and Thermomyces lanuginosa lipase (TLL), no FRET was observed. Under these conditions, no adsorption of TLL was detected using an ELISA. In contrast, FRET occurred when cis‐PnA was spread over an aqueous subphase containing NaTDC and TLL. The FRET signals observed were attributed to the interactions between the adsorbed TLL and the cis‐PnA monomolecular films. Comparisons between the fluorescence emission spectra corresponding to the bulk phase and the aspirated film, in the presence and absence of TLL, showed that cis‐PnA was undetectable in the bulk phase. We concluded that the FRET originated from the interface and not from the bulk phase. Using surface FRET, we estimated that the surface excess of the catalytically inactive mutant, TLL(S146A), was 1.6 higher than that present in the wild‐type TLL. This finding is in agreement with independent measurements of the surface excess of TLL and TLL(S146A) on monomolecular films of cis‐PnA. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 65: 121–128, 2002
Spectroscopic studies and PM5 semiempirical calculations of new Schiff bases of gossypol with polyoxaalkylamines
Authors: Przybylski Piotr , Bartl Franz , Brzezinski Bogumil 
Published: September 2002

AbstractThree Schiff bases of racemic gossypol with polyoxaalkylamines were synthesized and studied by FTIR and 1H‐NMR spectroscopy, and their structures were calculated by the PM5 semiempirical method. These Schiff bases exist in the solid state and in solutions as enamine forms. An increasing length of the polyoxaalkyl chain causes the increase of the interaction of the oxygen atoms of this chain with the OH groups in the 6,6′ positions. This interaction is very well evidenced in the FTIR and 1H‐NMR spectra. The structures of the Schiff bases and the hydrogen bonds within these structures are discussed. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 65: 111–120, 2002
Fourier transform IR and Fourier transform Raman spectroscopy studies of metallothionein‐III: Amide I band assignments and secondary structural comparison with metallothioneins‐I and ‐II
Authors: Shi Yan‐Bo , Fang Jiang‐Lin , Liu Xiao‐Yu , Du Liang , Tang Wen‐Xia 
Published: September 2002

AbstractThe secondary structures of porcine brain Cu4Zn3‐metallothionein (MT)‐III and Cd5Zn2MT‐I, Cd5Zn2MT‐II, and Zn7MT‐I from rabbit livers in the solid state are investigated by Fourier transform IR spectroscopy (FTIR) and Fourier transform Raman spectroscopy (FT‐Raman). The Cu4Zn3MT‐III contains 26–28% β‐turns and half‐turns, 13–14% 310‐helices, 47–49% random coils, and 11–12% β‐extended chains. The structural comparison of porcine brain Cu4Zn3MT‐III with rabbit liver Cd5Zn2MT‐I (II) and Zn7MT‐I shows that the contents of the random coil structure are obviously increased. The results indicate that the insert of an acidic hexapeptide in the α domain of Cu4Zn3MT‐III possibly forms an α helix. However, because the bands assigned to the α‐helix and random coil structures are overlapped in the spectra, the content of random coil structures in Cu4Zn3MT‐III is therefore higher than those in Cd5Zn2MT‐I, Cd5Zn2MT‐II, and Zn7MT‐I. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 65: 81–88, 2002
Study of wheat high molecular weight 1Dx5 subunit by 13C and 1H solid‐state NMR. II. Roles of nonrepetitive terminal domains and length of repetitive domain
Authors: Alberti Enrica , Gilbert Simon M. , Tatham Arthur S. , Shewry Peter R. , Naito Akira , Okuda Kanna , Saitô Hazime , Gil Ana M. 
Published: September 2002

AbstractThis work follows a previous article that addressed the role of disulfide bonds in the behavior of the 1Dx5 subunit upon hydration. Here the roles of nonrepetitive terminal domains present and the length of the central repetitive domain in the hydration of 1Dx5 are investigated. This was achieved by comparing the hydration behavior of suitable model samples determined by 13C‐ and 1H‐NMR: an alkylated 1Dx5 subunit (alk1Dx5), a recombinant 58‐kDa peptide corresponding to the central repetitive domain of 1Dx5 (i.e., lacking the terminal domains), and two synthetic peptides (with 6 and 21 amino acid residues) based on the consensus repeat motifs of the central domain. The 13C cross‐polarization and magic angle spinning (MAS) experiments recorded as a function of hydration gave information about the protein or peptide fractions resisting plasticization. Conversely, 13C single pulse excitation and 1H‐MAS gave information on the more plasticized segments. The results are consistent with the previous proposal of a hydrated network held by hydrogen‐bonded glutamines and possibly hydrophobic interactions. The nonrepetitive terminal domains were found to induce water insolubility and a generally higher network hindrance. Shorter chain lengths were shown to increase plasticization and water solubility. However, at low water contents, the 21‐mer peptide was characterized by higher hindrance in the megahertz and kilohertz frequency ranges compared to the longer peptide; and a tendency for a few hydrogen‐bonded glutamines and hydrophobic residues to remain relatively hindered was still observed, as for the protein and large peptide. It is suggested that this ability is strongly dependent on the peptide primary structure. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 65: 158–168, 2002
High‐throughput screening and quantitative structure‐efficacy relationship models of potential displacer molecules for ion‐exchange systems
Authors: Mazza Cecilia B. , Rege Kaushal , Breneman Curt M. , Sukumar N. , Dordick Jonathan S. , Cramer Steven M. 
Published: September 2002

AbstractA technique is presented for the high‐throughput screening of ion‐exchange displacers. Potential displacers were employed to displace proteins in parallel batch ion‐exchange experiments. The percentage of protein displaced from a particular stationary phase was then used as a parameter to rank the displacers. By employing this technique, a large number of molecules possessing a range of affinities and properties could be rapidly evaluated. This data was then used together with traditional and electron density‐based transferable atom equivalent (TAE) molecular descriptors computed for the displacer molecules to produce quantitative structure‐efficacy relationship (QSER) models using a genetic algorithm/partial least squares (GA/PLS) regression approach. The QSER models were generated using a portion of the protein‐displacement data, with the remainder serving as a test set. Descriptor selection and model building was accomplished using a genetic algorithm/partial least squares approach. The resulting models were found to have high‐correlation coefficients and could be used to accurately predict the behavior of molecules not included in the training set. In addition, the models were employed to examine a virtual library of displacers based on modifications of neomycin to provide further insight into displacer design. The results presented here indicate that it may be possible to design displacers that can dramatically improve the effective selectivity of ion‐exchange chromatographic materials. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 60–72, 2002.
The use of microscale processing technologies for quantification of biocatalytic Baeyer‐Villiger oxidation kinetics
Authors: Doig Steven D. , Pickering Samuel C. R. , Lye Gary J. , Woodley John M. 
Published: September 2002

AbstractMicroscale processing techniques would be a useful tool for the rapid and efficient collection of biotransformation kinetic data as a basis for bioprocess design. Automated liquid handling systems can reduce labor intensity while the small scale reduces the demand for scarce materials such as substrate, product, and biocatalyst. Here we illustrate this concept by establishing the use of several microwell formats (96‐round, 96‐deep square and 24‐round well microtiter plates) for quantification of the kinetics of the E. coli TOP10 [pQR239] resting cell catalyzed Baeyer‐Villiger oxidation of bicyclo[3.2.0]hept‐2en‐6‐one using glycerol as a source of reducing power. By increasing the biocatalyst concentration until the biotransformation rate was oxygen mass‐transfer limited we can ensure that kinetic data collected are in the region away from oxygen limitation. Using a 96‐round well plate the effect of substrate (bicyclo[3.2.0]hept‐2en‐6‐one) concentration on the volumetric CHMO activity was examined and compared to data collected from 1.5‐L stirred‐tank experiments. The phenomenon and magnitude of substrate inhibition, observed at the larger scale, was accurately reproduced in the microwell format. We have used this as an illustrative example to demonstrate that under adequately defined conditions, automated microscale processing technologies can be used for the collection of quantitative kinetic data. Additionally, by using the experimentally determined stoichiometry for product formation and glycerol oxidation, we have estimated the maximum oxygen transfer rates as a function of well geometry and agitation rate. Oxygen‐transfer rates with an upper limit of between 33 mmol · L−1 · h−1 (based solely on product formation) and 390 mmol · L−1 · h−1 (based on product formation and glycerol oxidation) were achieved using a 96‐square well format plate shaken at 1300 rpm operated with a static surface area to volume ratio of 320 m2 · m−3. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 42–49, 2002.
Production of D‐amino acid oxidase (DAO) of Trigonopsis variabilis in Schizosaccharomyces pombe and the characterization of biocatalysts prepared with recombinant cells
Authors: Isoai Atsushi , Kimura Hidetoshi , Reichert Arno , Schörgendorfer Kurt , Nikaido Kiyokazu , Tohda Hideki , Giga‐Hama Yuko , Mutoh Norihiro , Kumagai Hiromichi 
Published: September 2002

AbstractThe cDNA of D‐amino acid oxidase (DAO) gene isolated from Trigonopsis variabilis was expressed in Schizosaccharomyces pombe. A clone, ASP327‐10, transformed with plasmid vector, pTL2M5DAO, expressed catalytically active DAO in the presence of G418, and converted Cephalosprin C to α‐ketoadipyl‐7‐cephalosporanic acid (KA‐7‐ACA) and glutaryl‐7‐aminocephalosporanic acid (GL‐7‐ACA). Biocatalysts were prepared using ASP327‐10 and T. variabilis, and evaluated to demonstrate the feasibility of recombinant S. pombe for industrial application. The cells were immobilized by crosslinking polyethylene imine after glutardialdehyde (GDA) fixation and permeabilization by alkaline treatment. Although the biocatalyst prepared from ASP327‐10 exhibited DAO activity, catalase activity still remained fully even after permeabilization, under which condition, the catalase activity of T. variabilis decreased to 20–30%. Heat treatment was required before cell fixation by GDA to inactivate the catalase in S. pombe. This improved the efficiency of bioconversion to GL‐7‐ACA, but caused poor mechanical strength in the biocatalyst of S. pombe. To overcome this weakness, a catalase‐deficient host strain was obtained by ethylmethansulfate mutagenesis. Moreover, taking economics into consideration, the integrative vector, pTL2M5DAO‐8XL, with multi‐copies of expression cassette was constructed to express DAO in S. pombe even in the absence of G418. The newly established integrant, ASP417‐7, did not exhibit any catalase activity so that heat treatment was not required. The obtained integrant and its biocatalyst were significantly improved in GL‐7ACA conversion ability and mechanical strength. This study demonstrates that the established integrant is a potential candidate as an alternative source of DAO enzyme. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 22–32, 2002.
Pilot‐scale production of (S)‐styrene oxide from styrene by recombinant Escherichia coli synthesizing styrene monooxygenase
Authors: Panke Sven , Held Martin , Wubbolts Marcel G. , Witholt Bernard , Schmid Andreas 
Published: September 2002

AbstractRecombinant Escherichia coli JM101(pSPZ10) cells produce the styrene monooxygenase of Pseudomonas sp. strain VLB120, which catalyzes the oxidation of styrene to (S)‐styrene oxide at an enantiomeric excess larger than 99%. This biocatalyst was used to produce 388 g of styrene oxide in a two‐liquid phase 30‐L fed‐batch bioconversion. The average overall volumetric activity was 170 U per liter over a period of more than 10 h, equivalent to mass transfer rates of 10.2 mmoles per liter per hour at a phase ratio of 0.5. At this transfer rate, the biotransformation system appeared to be substrate mass‐transfer limited. The reactor had an estimated power input in the order of 5 W · L−1, which is close to values typically obtained with commercially operating units. The product could be easily purified by fractional distillation to a purity in excess of 97%. The process illustrates the feasibility of recombinant whole cell biotransformations in two‐liquid phase systems with toxic substrates and products. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 33–41, 2002.