bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of human laryngeal muscle protein using two‐dimensional electrophoresis and mass spectrometry
Authors: Li Zhao‐Bo , Lehar Mohamed , Braga Natasha , Westra William , Liu Li‐Hong , Flint Paul W.
Published: July 2003

Proteomic analysis was performed to construct a protein database for human laryngeal muscle. Thyroarytenoid (TA) muscle specimens were obtained from six post mortem cases within 24 h of death. Isoelectric focusing was performed by using immobilized pH gradient strips followed by 12% sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. Silver stained gels were then analyzed using PDQuest software to locate, quantify and match spots. Proteins were identified by matrix‐assisted laser desorption/ionization‐mass spectrometry on the basis of peptide mass fingerprinting following in‐gel digestion with trypsin. Comparison of protein distribution between broad and narrow pH range gels demonstrated that 75% of all protein spots from human TA muscle were located within the pH range 5–8, and between mass 15–120 kDa. Based on peptide mass fingerprinting, 75 proteins were identified and classified into six functional groups. These include membrane proteins (8.5%), cytoskeletal and myofibrillar proteins (14.6%), energy production proteins (28%), proteins associated with stress responses (8.5%), and protein associated with transcription regulation (10.9%). Approximately one‐third (29%) were categorized as “other proteins”. This data provides an initial reference map for comparative studies of protein expression in human and laryngeal muscle. Further development of this database will provide a valuable resource for molecular analysis of normal and pathologic conditions affecting human striated muscle.
The Proteomics Standards Initiative
Authors: Orchard Sandra , Hermjakob Henning , Apweiler Rolf
Published: July 2003

The Proteomics Standards Initiative (PSI) aims to define community standards for data representation in proteomics and to facilitate data comparison, exchange and verification. Progress has been made in the development of common standards for data exchange in the fields of both mass spectrometry and protein‐protein interaction. A proteomics‐specific extension is being created for the emerging American Society for Tests and Measurements mass spectrometry standard, which will be supported by manufacturers of both hardware and software. A data model for proteomics experimentation is under development and discussions on a public repository for published proteomics data are underway. The Protein‐Protein Interactions group expects to publish the Level 1 PSI data exchange format for protein‐protein interactions soon and discussions as to the content of Level 2 have been initiated.
Book Review: Essentials of Genomics and Bioinformatics. By Christoph W. Sensen
Authors: Mayer Klaus
Published: July 2003

No abstracts.
Book Review: Analysing Gene Expression: A Handbook of Methods,Possibilities and Pitfalls (Two volumes). By Stefan Lorkowsky and Paul Cullen (Editors)
Authors: Hanash Sam
Published: July 2003

No abstracts.
Editorial: Proteomics 7/2003
Authors: Patton Wayne F.
Published: July 2003

No abstracts.
Interfacial fracture toughness between glassy polymer networks
Authors: Perez‐Salas U. , Briber R. M. , Rafailovich M. H. , Sokolov J.
Published: July 2003

The interfacial fracture energy, Gc, between glassy crosslinked polystyrene samples was studied with the symmetric double‐cantilever beam test. Compression‐molded polystyrene slabs were crosslinked by γ irradiation in vacuo. The fracture samples were prepared by the welding of two crosslinked polystyrene slabs under contact pressure for 1 h at 150 °C, which was above the glass‐transition temperature for polystyrene (≅104 °C). The fracture toughness tests were performed at room temperature. The interfacial fracture energy was studied as a function of the crosslink density of the slabs. It was found that the interfacial fracture energy decreased with increasing crosslink density. A least‐squares fit of the data showed that the interfacial fracture energy scaled as N, where Nc is the weight‐average chain length between crosslinks (in number of monomer units). A comparison with the predictions made by different models on weak interfaces was made. It was found that if the loops of the network were identified as the connectors responsible for adhesion at the glassy network‐network interfaces, the model by Xu et al. predicted that Gc would scale as N, consistent with the trends in the data. Using the expression for Gc from this model to fit the data the value for the static friction constant per monomer for polystyrene was found to be fmono = 3.5 ± 0.7 × 10−12 N/monomer, in good agreement with the values found in the literature. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1902–1908, 2003
Viscoelastic relaxation mechanisms of conventional polypropylene toughened by a plastomer
Authors: Prieto Óscar , Pereña José M. , Benavente Rosario , Pérez Ernesto , Cerrada María L.
Published: July 2003

Plastomers are new alternatives that provide a higher impact strength in polypropylene synthesized by conventional methods. This study presents an analysis of the structure and thermal characterization of two sets of polypropylene/plastomer blends. The difference between the two polypropylene samples is their molecular weight. With the structural knowledge obtained, a comprehensive analysis of the different relaxation processes has been performed. Neither component is miscible. The area under the loss tangent curves provides preliminary information about how the toughness is enhanced with this type of impact modifier. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1878–1888, 2003
Enhanced soil sorption of methidathion using sewage sludge and surfactants
Authors: Sánchez Lourdes , Romero Esperanza , Sánchez‐Rasero Francisco , Dios Gonzalo , Peña Aránzazu
Published: July 2003

Batch experiments were carried out to examine the partitioning of an organophosphorus insecticide, methidathion, in non‐amended agricultural soil and soil amended with urban sewage sludge and/or different types of surfactant. Kinetic data showed that sewage sludge significantly reduced adsorption rate, whereas amendment of the soil with the cationic surfactant tetradecyltrimethylammonium bromide (TDTMA) at 10× CMC (critical micellar concentration) increased the adsorption rate by a factor of 10. The adsorption isotherms were evaluated using the Freundlich model. The soil adsorption capacity for methidathion was enhanced by amendment with sewage sludge and even more significantly with TDTMA at 10× CMC or combined with sewage sludge. TDTMA conferred a high hydrophobic character to the soil, enhancing the adsorption capacity of the rather hydrophobic methidathion. The amendment of soil both with sewage sludge and TDTMA combines the increased hydrophobicity with a higher surfactant retention by organic matter, due to an increase in cation exchange capacity, which promotes even more the adsorption capacity for the insecticide. An anionic surfactant, linear alkylbenzene sulfonate, and the non‐ionic Tween 80 only induced a slight modification in the kinetics and adsorption of methidathion. Copyright © 2003 Society of Chemical Industry
Insecticide resistance in Egyptian populations of the cotton whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae)
Authors: Kady Hafez El , Devine Gregor J
Published: July 2003

Three collections of Bemisia tabaci were taken from cotton and vegetable crops at the beginning of the growing season in Egypt. These displayed marked resistance to the carbamates carbosulfan (ca 20‐ to 50‐fold) and aldicarb (ca 40‐ to 80‐fold) and moderate resistance to the pyrethroids cypermethrin (ca 10‐ to 30‐fold) and lambda‐cyhalothrin (ca 10‐ to 25‐fold). They displayed no resistance to the organophosphates profenofos and pirimiphos‐methyl, or to imidacloprid. Another population, collected at the end of the growing season, differed markedly in its response. In this population, resistance to carbosulfan remained high (ca 40‐fold), resistance to profenofos and cypermethrin was increased (ca 20‐ and 50‐fold respectively) and a slight resistance to imidacloprid was detected (ca 6‐fold). Resistance to cypermethrin and profenofos was shown to be similar among adults and nymphs. Irrespective of collection date, none of the populations showed resistance to pyriproxyfen. These Egyptian populations were compared with two representative Israeli populations. The differences between their resistance profiles is discussed in terms of their collection date, their geographical proximity and the patterns of insecticide use at their sites of collection. Copyright © 2003 Society of Chemical Industry
Isolation and in vitro and in vivo activity against Phytophthora capsici and Colletotrichum orbiculare of phenazine‐1‐carboxylic acid from Pseudomonas aeruginosa strain GC‐B26
Authors: Lee Jung Yeop , Moon Surk Sik , Hwang Byung Kook
Published: July 2003

The bacterial strain GC‐B26, which showed strong antifungal and anti‐oomycete activity against some plant pathogens, was isolated from a grassland soil in Korea. Based on morphological, physiological and biochemical characteristics, GC‐B26 was identical to Pseudomonas aeruginosa (Schroeter) Migula. The antibiotic G26A, active against Phytophthora capsici Leonian and Colletotrichum orbiculare (Berk & Mont) van Arx, was isolated from the culture filtrates of Ps aeruginosa strain GC‐B26 using various chromatographic procedures. The EI mass and UV spectral results indicated that G26A is an analogue of phenazines, having molecular formula C13H8N2O2 (M+, m/z 224.0664). On the basis of NMR spectral data, G26A was confirmed as phenazine‐1‐carboxylic acid. C orbiculare, P capsici and Pythium ultimum Trow were most sensitive to G26A, with MIC values of approximately 5 µg ml−1. However, no antimicrobial activity was found against yeasts and bacteria, even at a concentration of over 100 µg ml−1. Treatment with the antibiotic gave highly significant protective activity against the development of Phytophthora disease on pepper and anthracnose on cucumber plants. The disease control efficacy was only slightly less than that of the commercial fungicides metalaxyl and chlorothalonil. Copyright © 2003 Society of Chemical Industry
The cyclization transformation of the sulfonylurea herbicide flupyrsulfuron in the soil of winter wheat crops
Authors: Rouchaud Jean , Neus Olivier , Moulard Claude
Published: July 2003

The synthesis of 1‐(4,6‐dimethoxypyrimidine‐2‐yl)‐7‐trifluoromethyl‐1,2,3,4‐tetrahydropyrido[2,3‐d]pyrimidin‐2,4‐dione has been carried out in such a way that the dimethoxypyrimidine substituent was unambiguously in position 1 of the pyrido[2,3‐d]pyrimidine ring. This regioisomer was obtained by cyclization with phosgene of 2‐(4,6‐dimethoxypyrimidin‐2‐ylamino)‐6‐trifluoromethylnicotinamide which had previously been ionized with sodium hydride. It was shown to be identical to the metabolite generated in the soil of winter wheat crops treated previously with the sulfonylurea herbicide flupyrsulfuron‐methyl [(methyl 2‐(4,6‐dimethoxypyrimidin‐2‐ylcarbamoylsulfamoyl)‐6‐trifluoromethylnicotinate]. The position of the dimethoxypyrimidine substituent had not previously been assigned unambiguously to positions 1 or 3 of the pyrido[2,3‐d]pyrimidine ring. The regioisomer was also identical to the cyclization compound generated chemically from flupyrsulfuron in a sterile water buffer at pH 9. The metabolism pathways of flupyrsulfuron in soil are discussed in the light these structure determinations and compared with the soil metabolism pathways frequently observed with other sulfonylurea herbicides. Copyright © 2003 Society of Chemical Industry
Evaluation of chemical and integrated strategies as alternatives to methyl bromide for the control of root‐knot nematodes in Greece
Authors: Giannakou Ioannis O , Karpouzas Dimitrios G
Published: July 2003

Current environmental awareness has led to a greater demand for alternative nematode control strategies. Three field experiments were established to compare management tactics on cucumber in commercial greenhouses naturally infested with root‐knot nematodes (Meloidogyne spp). Cucumber rootstocks which have shown resistance to soil‐borne diseases were tested to reveal any resistance/tolerance to root‐knot nematodes, and integration of these rootstocks with nematicides was investigated. Metham‐sodium and 1,3‐dichloropropene (1,3‐D) provided good control of nematode populations when their application was followed by the application of a non‐fumigant nematicide such as cadusafos or oxamyl. Neither fumigant could provide season‐long control of nematode populations, and a further application of cadusafos was required for satisfactory control. The efficacy of metham‐sodium was significantly increased when injected into soil in comparison with its application through the drip irrigation system. The use of rootstocks resistant to soil‐borne fungal pathogens used together with chemical means of nematode control provided promising results for their further use in integrated strategies as alternatives to methyl bromide. However, the latter was the superior treatment for the control of root‐knot nematodes in soil infested with residues of galled roots. Dazomet, metham‐sodium nor the non‐fumigant nematicides oxamyl and fenamiphos could reduce nematode population as efficiently as methyl bromide. None of the chemicals tested except methyl bromide could enter galled roots and kill surviving nematodes. Copyright © 2003 Society of Chemical Industry
Spatial variability of atrazine dissipation in an allophanic soil
Authors: Müller Karin , Smith Roger E , James Trevor K , Holland Patrick T , Rahman Anis
Published: July 2003

The small‐scale variability (0.5 m) of atrazine (6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine) concentrations and soil water contents in a volcanic silt loam soil (Haplic Andosol, FAO system) was studied in an area of 0.1 ha. Descriptive and spatial statistics were used to analyse the data. On average we recovered 102% of the applied atrazine 2 h after the herbicide application (CV = 35%). An increase in the CV of the concentrations with depth could be ascribed to a combination of extrinsic and intrinsic factors. Both variables, atrazine concentrations and soil water content, showed a high horizontal variability. The semivariograms of the atrazine concentrations exhibited the pure nugget effect, no pattern could be determined along the 15.5‐m long transects on any of the seven sampling days over a 55‐day period. Soil water content had a weak spatial autocorrelation with a range of 6–10 m. The dissipation of atrazine analysed using a high vertical sampling resolution of 0.02 m to 0.2 m showed that 70% of the applied atrazine persisted in the upper 0.02‐m layer of the soil for 12 days. After 55 days and 410 mm of rainfall the centre of the pesticide mass was still at a soil depth of 0.021 m. The special characteristics of the soil (high organic carbon content, allophanic clay) had a strong influence on atrazine sorption and mobility. The mass recovery after 55 days was low. The laboratory degradation rate for atrazine, determined in a complementary incubation study and corrected for the actual field temperature using the Arrhenius equation, only accounted for about 35% of the losses that occurred in the field. Results suggest field degradation rates to be more changeable in time and much faster than under controlled conditions. Preferential flow is discussed as a component of the field transport process. Copyright © 2003 Society of Chemical Industry
Effects of a juvenile hormone analog, pyriproxyfen, on Thrips tabaci (Thysanoptera: Thripidae)
Authors: Liu Tong‐Xian
Published: July 2003

Effects of a juvenile hormone analog, pyriproxyfen, on various developmental stadia of the onion thrips, Thrips tabaci Lindeman, were determined on cabbage leaves in the laboratory. Pyriproxyfen was applied at 0.064 or 0.128 g AI liter−1 on leaves (residual contact–ingestion), thrips (direct contact) and leaf–thrips (residue contact–ingestion–direct contact). Pyriproxyfen did not have any significant lethal effects on thrips pupae in any treatment. Lethal effects on thrips larvae varied depending on application method and dosage. In the leaf and the leaf–thrips treatments, few larvae and pre‐pupae molted to the next stage, and none developed to adults. In contrast, in the thrips‐only treatment, pyriproxyfen did not show any significant lethal effects. The developmental times of larvae and pre‐pupae were prolonged when larvae were treated with pyriproxyfen, and those of pre‐pupae and pupae were shortened when pre‐pupae and pupae were treated. The longevity and survival rates of thrips adults were generally shorter when they contacted and ingested pyriproxyfen‐treated leaves than those in water control. Significantly fewer progeny (0.22–1.15 larvae per female) were produced by females that had fed on and been in contact with the pyriproxyfen‐treated leaves than by those in the water control (11.94 larvae per female). However, the number of progeny produced by the thrips females increased significantly (3.32–7.28 larvae per female) when the females were transferred to untreated leaves after feeding on treated leaves for 5 days; the daily larval hatching pattern was similar to those in water control, indicating that female adults were able to produce viable eggs when untreated food was offered. Copyright © 2003 Society of Chemical Industry
Management of insecticide resistance in Oriental fruit moth (Grapholita molesta; Lepidoptera: Tortricidae) populations from Ontario
Authors: Kanga Lambert HB , Pree David J , van Lier Jennifer L , Walker Gerald M
Published: July 2003

The development of resistance in the Oriental fruit moth, Grapholita molesta (Busck) to organophosphorus (OP) insecticides (azinphos‐methyl and phosmet) is a serious threat to the tender fruit industry in Ontario (50% crop losses in 1994). Resistance to carbamate insecticides and increased survival of field‐collected moths at diagnostic concentrations of pyrethroids were widespread. As a result, four different treatment regimes were tested to manage resistance in G molesta, and the changes in resistance frequencies under each treatment regime were monitored from 1996 to 1999. The data indicated that the levels of resistance were significantly influenced by the various treatment regimes. The seasonal pattern of resistance was similar for all treatment regimes, in that resistance peaked in mid‐season and declined in the late season. Levels of resistance in G molesta to OPs decreased from 55% to 14% and that to pyrethroids declined from 30% to 10% from 1996 to 1999 under a treatment regime consisting of endosulfan–organophosphate–pyrethroid rotation. Similarly, under a treatment regime implemented in commercial orchards (organophosphate–pyrethroid rotation), resistance to OP insecticides declined from 50% to 12% and resistance to pyrethroids evolved to around 16%. The overall data indicated that resistance was unstable; a strategy based on rotation of insecticides by class for each generation of G molesta was successful in managing resistance to both OP and pyrethroid insecticides. The rotational strategy has been widely adopted by growers and is applied to ca 85% of the acreage. For the Department of Agriculture and Agri‐Food, Government of Canada, © Minister of Public Works and Government Services Canada 2003. Published for SCI by John Wiley & Sons, Ltd.
Vitamin K requirement in Danish anticoagulant‐resistant Norway rats (Rattus norvegicus)
Authors: Markussen Mette DK , Heiberg Ann‐Charlotte , Nielsen Robert , Leirs Herwig
Published: July 2003

Resistance to warfarin has been connected to an increase in dietary requirement for vitamin K in British strains of the Norway rat, Rattus norvegicus (Berk). This study examines vitamin K requirement of Danish anticoagulant‐resistant Norway rats using a vitamin K deficient feeding test. Wild bromadiolone‐resistant rats sampled from different localities in Denmark and rats from bromadiolone‐resistant and susceptible laboratory strains were fed on a vitamin K deficient diet over a maximum period of 15 days. Development of vitamin K deficiency, measured as reduced blood‐clotting capacity, took place in 43% of the Danish resistant rats and was independent of sex, treatment with supplementary vitamin K3 and sampling locality. Development of deficiency was slower for resistant rats that were supplemented with vitamin K3 prior to the feeding test, suggesting storage of the vitamin K in a vitamin body pool. Intraperitoneal administration of vitamin K1 revealed that 80 µg vitamin K1 kg−1 bodyweight was sufficient to restore normal blood clotting activity in deficient rats, while 60 µg vitamin K1 kg−1 bodyweight was insufficient. We conclude that vitamin K requirement is moderately increased in Danish homozygous resistant rats whereas heterozygous resistant rats only have a minor increase in vitamin K requirement compared with susceptible rats. We found no indication of different resistance types being present in our test material since vitamin K requirement was not different between rats from separate sampling localities. Copyright © 2003 Society of Chemical Industry
The toxic and anti‐feedant activity of 2H‐pyridazin‐3‐one‐substituted 1,3,4‐oxadiazoles against the armyworm Pseudaletia separata (Walker) and other insects and mites
Authors: Huang Qingchun , Qian Xuhong , Song Gonghua , Cao Song
Published: July 2003

The toxicities and anti‐feedant activities of thirteen asymmetrical 1,3,4‐oxadiazoles containing a 2H‐pyridazin‐3‐one group were investigated. The compounds were shown to possess considerable activity in retarding the development of larvae of a number of Lepidoptera, but they were all inactive against Homoptera, Diptera and Acarina. The compounds had powerful anti‐feedant activity comparable with that of azadirachtin. The toxic symptoms of the poisoned larvae indicated that the compounds were novel insect growth regulators with a mode of action that might be similar to the chitin‐synthesis inhibition of oxadiazole compounds and/or the juvenile hormone effect of pyridazinone compounds. Copyright © 2003 Society of Chemical Industry
Flufenacet herbicide treatment phenocopies the fiddlehead mutant in Arabidopsis thaliana
Authors: Lechelt‐Kunze Christa , Meissner Ruth C , Drewes Mark , Tietjen Klaus
Published: July 2003

In order to study the mode of action of herbicides we conducted a pilot study analysing phenotype and gene expression of flufenacet‐ and benfuresate‐treated Arabidopsis thaliana (L) Heynhoe plants. Treatments with either herbicide caused phenocopies of the known Arabidopsis mutant fiddlehead, displaying fused organs and the typical fiddlehead‐like inflorescence. Herbicide treatments of other plant species, including monocots, also gave rise to analogous organ fusions, indicating the presence of the target in a broad range of plants. Furthermore, many other herbicides with a proposed similar mode of action, eg chloroacetanilides, produced comparable fusion phenotypes in plants. The fiddlehead gene encodes a putative very‐long‐chain fatty acid elongase (VLCFAE), which corroborates earlier biochemical results pointing to the inhibition of VLCFA synthesis as mode of action of flufenacet. Gene expression profiles of herbicide‐treated plants using the first 8247 gene Arabidopsis gene array of Affymetrix provided additional clues in support of inhibition of VLCFA synthesis. We discuss fiddlehead‐like elongases as plant specific targets for flufenacet and many other herbicides. Copyright © 2003 Society of Chemical Industry
Contact activity of difenzoquat differs from that of paraquat
Authors: Li Zhaohu , Nandula Vijay K , Messersmith Calvin G
Published: July 2003

Difenzoquat herbicide is used for post‐emergence control of wild oat (Avena fatua L) in small grain crops. Its mechanism of action is not known, but appears to have both paraquat‐like contact activity and systemic growth‐inhibition activity. Experiments were conducted in vitro to compare the contact activity of difenzoquat and paraquat, to examine the contact activity of difenzoquat in difenzoquat‐resistant (accession LCS) and ‐susceptible (accession SB 18) A fatua biotypes and ‐tolerant ‘Ernest’ and ‐susceptible ‘Verde’ hard red spring wheat (Triticum aestivum L) cultivars, and to investigate the role of differential DNA synthesis as a mechanism for difenzoquat resistance. Difenzoquat at 1 mM induced significant electrolyte leakage from resistant and susceptible A fatua leaf tissue in both light and dark, but paraquat at 1 mM induced electrolyte leakage only in light and not in dark. Difenzoquat at 1 mM under light induced more electrolyte leakage from resistant and susceptible A fatua than from tolerant ‘Ernest’ and susceptible ‘Verde’ wheat. Paraquat under light conditions induced more electrolyte leakage than difenzoquat, but no significant differences among A fatua accessions and wheat cultivars were detected. Difenzoquat under light did not decrease chlorophyll levels for either A fatua accessions or wheat cultivars, whereas paraquat decreased chlorophyll content of all four plant types. Inhibition of DNA synthesis was not significantly different between susceptible and resistant A fatua, but was significantly greater in susceptible ‘Verde’ than tolerant ‘Ernest’ wheat. These data suggest that difenzoquat and paraquat, have different modes of contact activity. Copyright © 2003 Society of Chemical Industry
Diagnosis of dehydratase inhibitors in melanin biosynthesis inhibitor (MBI‐D) resistance by primer‐introduced restriction enzyme analysis in scytalone dehydratase gene of Magnaporthe grisea
Authors: Kaku Koichiro , Takagaki Makiichi , Shimizu Tsutomu , Nagayama Kozo
Published: July 2003

We have established a simple diagnosis method for rice blast fungus resistant to MBI‐D. This involves the preparation of PCR templates directly from the lesions in combination with primer‐introduced restriction enzyme analysis PCR (PIRA‐PCR). Copyright © 2003 Society of Chemical Industry
Comparative evaluation of four trityl‐type amidomethyl polystyrene resins in Fmoc solid phase peptide synthesis
Authors: Zikos Christos , Livaniou Evangelia , Leondiadis Leondios , Ferderigos Nikolas , Ithakissios Dionyssis S. , Evangelatos Gregory P.
Published: July 2003

Four trityl‐type (i.e. non‐substituted trityl‐, o‐Cl‐trityl‐, o‐F‐trityl‐ and p‐CN‐trityl‐) amidomethyl polystyrene resins were evaluated comparatively, in terms of the stability of the trityl‐ester bond in slightly acidic dichloromethane solutions, and the p‐CN‐trityl‐amidomethyl polystyrene resin was found to be the most stable of them. The above resins were applied, in parallel with Wang benzyl‐type resin, well known for its stability in mild acidic conditions, to the Fmoc solid phase synthesis of the 43‐amino acid residue long bioactive peptide thymosin beta‐4. Independent of their differences in acid sensitivity, the resins seemed to function equally well under the conditions used, since pure thymosin beta‐4 was obtained with a final yield of approximately 30% from each resin. The trityl‐type amidomethyl polystyrene resins were also applied, in parallel with the Wang resin, to the Fmoc solid phase synthesis of a bioactive peptide containing proline at its C‐terminus, i.e. the N‐terminal tetrapeptide of thymosin beta‐4, AcSDKP. In this case, the best yield (87%) was obtained with the o‐Cl‐trityl‐amidomethyl polystyrene resin, which may be the resin of choice, of those studied, for the Fmoc solid phase peptide synthesis. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Synthesis of the C‐terminal domain of the tissue inhibitor of metalloproteinases‐1(TIMP‐1)
Authors: Bódi József , Mihala Nikolett , Hajnal Andrea , Medzihradszky Katalin F. , Süli‐Vargha Helga
Published: July 2003

According to recent investigations, the C‐terminal domain of the tissue inhibitor of matrix metalloproteinases‐1 (TIMP‐1) is responsible for some biological effects that are independent of the enzyme‐inhibiting effect of the N‐terminal domain of the molecule. The C‐terminal domain has been prepared for structure–biological activity investigations. After the chemical synthesis and the folding of the linear peptide, LC‐MS and MALDI‐MS analysis revealed that two isomers with different disulphide bond arrangements were formed. Since more than 30 folding experiments resulted in products with a very similar HPLC‐profile, it was concluded that in the absence of the TIMP‐1 N‐terminal domain no entirely correct folding of the C‐terminal domain occurred. Furthermore, it was observed that, in spite of several purification steps, mercury(II) ions were bound to the 6SH‐linear peptide; it was demonstrated—using disulphide bonded TIMP‐1(Cys145‐Cys166) as a model—that mercury(II) ions can cause peptide degradation at pH 7.8 as well as in 0.1% trifluoroacetic acid. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Isolation of a napin‐like polypeptide with potent translation‐inhibitory activity from chinese cabbage (Brassica parachinensis cv green‐stalked) seeds
Authors: Ngai Patrick H. K. , Ng T. B.
Published: July 2003

A heterodimeric napin‐like polypeptide was isolated from Brassica parachinensis seeds with a procedure involving ion exchange chromatography on DEAE‐cellulose, affinity chromatography on Affi‐gel blue gel, FPLC‐ion exchange chromatography on Mono S and FPLC‐gel filtration on Superdex 75. The N‐terminal sequence of the 5 kDa subunit of the polypeptide (PAGPFRIPKKRKKEE) showed high homology with other 2S storage proteins like napins and albumins. The polypeptide potently inhibited translation in a cell free system with an IC50 of 6.2 nM. The translation‐inhibiting activity of the polypeptide was relatively stable in the pH range 6–11 and in the temperature range 10–50°C. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
The use of NMR chemical shifts to analyse the MD trajectories: simulation of bovine pancreatic trypsin inhibitor dynamics in water as a test case for solvent influences
Authors: Busetta Bernard , Picard Philippe , Precigoux Gilles
Published: July 2003

In this paper the NMR secondary chemical shifts, that are estimated from a set of 3D‐structures, are compared with the observed ones to appraise the behaviour of a known x‐ray diffraction structure (of the bovine pancreatic trypsin inhibitor protein) when various molecular dynamics are applied. The results of a 200 ps molecular dynamics under various conditions are analysed and different ways to modify the molecular dynamics are considered. With the purpose of avoiding the time‐consuming explicit representation of the solvent (water) molecules, an attempt was made to understand the role of the solvent and to develop an implicit representation, which may be refined. A simulation of hydrophobic effects in an aqueous environment is also proposed which seems to provide a better approximation of the observed solution structure of the protein. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Lipid and carbohydrate based adjuvant/carriers in immunology
Authors: McGeary Ross P. , Olive Colleen , Toth Istvan
Published: July 2003

This review discusses various issues regarding vaccines; what are they and how they work, safety aspects, the role of adjuvants and carriers in vaccination, synthetic peptides as immunogens, and new technologies for vaccine development and delivery including the identification of novel adjuvants for mucosal vaccine delivery. There has been a recent increase of interest in the use of lipids and carbohydrates as adjuvants, and so a particular emphasis is placed on adjuvants derived from lipids or carbohydrates, or from both. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Disruption of the β‐sheet structure of a protected pentapeptide, related to the β‐amyloid sequence 17–21, induced by a single, helicogenic Cα‐tetrasubstituted α‐amino acid
Authors: Formaggio Fernando , Bettio Andrea , Moretto Vittorio , Crisma Marco , Toniolo Claudio , Broxterman Quirinus B.
Published: July 2003

Fifteen years ago it was shown that an α‐aminoisobutyric acid (Aib) residue is significantly more effective than an L‐Pro or a D‐amino acid residue in inducing β‐sheet disruption in short model peptides. As this secondary structure element is known to play a crucial role in the neuropathology of Alzheimer's disease, it was decided to check the effect of Aib (and other selected, helix inducer, Cα‐tetrasubstituted α‐amino acids) on the β‐sheet conformation adopted by a protected pentapeptide related to the sequence 17–21 of the β‐amyloid peptide. By use of FT‐IR absorption and 1H NMR techniques it was found that the strong self‐association characterizing the pentapeptide molecules in weakly polar organic solvents is completely abolished by replacing a single residue with Aib or one of its congeners. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Electronic density from structure factor determination in small deformed crystals
Authors: Putz Mihai V.
Published: July 2003

Starting from the integrated reflectivity expression, in the framework of dynamical X‐ray diffraction in small deformed crystals, there are derived the analytical formulae of Pendellösung and the associated structure factor, within symmetrical Laue diffraction geometry without absorption. The current approach provides the electronic density Fourier expansion. A movie for the electronic maps counting different elastic deformations is computed for the case of Si (fcc) structure. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 94: 222–231, 2003
Algebraic derivation of the iterative‐perturbative method as a global squeezing and displacement transformation
Authors: Urdaneta I. , Paz J. L.
Published: July 2003

We make use of iterative Bogoliubov transformations (IBT) and employ a procedure derived by Mundarain et al. to derive an approximate analytic expression for the evolution operator of a system consisting of a quartic oscillator coupled to a time‐dependent electric field. As a result, this expression resumes the whole iterative process as a global squeezing and displacement transformation in which the compression coefficients and translation parameters are obtained explicitly, thus giving a complete analytic structure to the process that supports and complements the conventional IBT and the bilinear approximation Echave, J., et al. J Chem Phys 1990, 92, 1188, which are mainly numerical and semiclassic approaches respectively. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 94: 179–188, 2003
Intramolecular proton transfer induced by divalent alkali earth metal cation in the gas state
Authors: Ai Hongqi , Bu Yuxiang , Li Ping
Published: July 2003

Interactions between divalent alkali earth metal (DAEM) ions M (MBe, Mg, Ca, Sr, Ba) and the second stable glycine conformer in the gas phase, which can transfer into the ground‐state glycine‐M2+ (except the glycine–Be2+) among each corresponding isomers when these divalent metal ions are bound, are studied at the hybrid three‐parameter B3LYP level with three different basis sets. Proton transfers from the hydroxyl to the amino nitrogen of the glycine without energy barriers have been first observed in the gas phase in these glycine–M2+ systems. The interaction between the glycine and these DAEM ions except beryllium and magnesium ion only create an amino hydrogen pointing to the original hydroxyl due to their weaker interaction relative to those divalent transition metal (DTM) ion‐bound glycine derivatives, being obviously different from that between the glycine and DTM ions, in which two amino hydrogens point to the original hydroxyl oxygen when these metal‐chelated glycine derivatives are produced. The interaction energy between the glycine and divalent magnesium would be the boundary of one or two amino hydrogens pointing to the hydrogyl oxygen, i.e., the −170.3 kcal/mol of binding energy is a critical point. Similar intramolecular proton transfer has also been predicted for those DTM ion‐chelated glycine systems; however, that in the gas state has not been observed in the monovalent metal ion‐coordinated glycine systems. The binding energy between some monovalent TM ion and the glycine is similar to that of the glycine–Ba2+, which has the lowest binding strength among these DAEM–ion chelated glycine complexes. The difference among them only lies in the larger electrostatic and polarized effects in the latter, which favor the stability of the zwitterionic glycine form in the gas phase. According to these observations, we predict that the zwitterionic glycine would exist in the field of two positive charges in the gas phase. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 94: 205–214, 2003
Zirconia‐based column high‐performance liquid chromatography/atmospheric pressure photoionization tandem mass spectrometric analyses of drug molecules in rat plasma
Authors: Hsieh Yunsheng , Merkle Kara , Wang Ganfeng
Published: July 2003

A method using zirconia‐based column high‐performance liquid chromatography (HPLC) interfaced with an atmospheric pressure photoionization (APPI) source and a tandem mass spectrometer (MS/MS) was developed for the quantitative determination of new chemical entities in rat plasma in support of pharmacokinetics studies. The ionization suppression resulting from endogenous components of the biological matrices on the quantitative zirconia‐based column HPLC/APPI‐MS/MS method was investigated using the post‐column infusion technique. The analytical results for ‘rapid rat pharmacokinetics’ for 12 drug discovery compounds, obtained by both silica‐based phase (S‐phase) and zirconia‐based phase (Z‐phase) chromatographic separation, are in good agreement in terms of accuracy. The application of a Z‐phase column for high‐temperature fast HPLC/MS/MS methods was explored to reduce the analysis time from 3 min to 30 s for column temperatures of 25–110°C, respectively. The chromatographic retention times and peak responses of all analytes were found to be reproducible under high‐temperature conditions following 100 continuous injections, with %CV less than 0.4 and 5, respectively. Copyright © 2003 John Wiley & Sons, Ltd.
Intact protein analysis by matrix‐assisted laser desorption/ionization tandem time‐of‐flight mass spectrometry
Authors: Lin Melanie , Campbell Jennifer M. , Mueller Dieter R. , Wirth Urs
Published: July 2003

Direct tandem mass spectrometric (MS/MS) analysis of small, singly charged protein ions by tandem time‐of‐flight mass spectrometry (TOFMS) is demonstrated for proteins up to a molecular mass of 12 kDa. The MALDI‐generated singly charged precursor ions predominantly yield product ions resulting from metastable fragmentation at aspartyl and prolyl residues. Additional series of C‐terminal sequence ions provide in some cases sufficient information for protein identification. The amount of sample required to obtain good quality spectra is in the high femtomolar to low picomolar range. Within this range, MALDI‐MS/MS using TOF/TOF™ ion optics now provides the opportunity for direct protein identification and partial characterization without prior enzymatic hydrolysis. Copyright © 2003 John Wiley & Sons, Ltd.
Investigation of apparent mass deviations in electrospray ionization tandem mass spectrometry of a benzophenone‐labeled peptide
Authors: Leite John F. , Dougherty Dennis A. , Lester Henry A. , Shahgholi Mona
Published: July 2003

In a previous study utilizing benzophenone‐based topological probes to study conformationally dependent changes in mouse muscle nicotinic acetylcholine receptor (nAChR) topology, electrospray ionization tandem mass spectrometric (ESI‐MS/MS) analysis led to a consistent −2.0 Da mass deviation from expected values. In the present study a synthetic peptide, corresponding to nAChR α1 subunit residues 130–139, was photolabeled. MS/MS analysis of this peptide using an ion trap confirmed the previously observed mass deviation, associated only with fragment ions that contain the incorporated benzophenone moiety. Analysis of peak profiles for the photolabeled ions does not indicate the typical ‘peak fronting’ that produces a mass shift when labile ions are prematurely ejected from the ion trap. Rather, hydrogen/deuterium (H/D) exchange experiments support the hypothesis that a chemical rearrangement involving phenyl migration and ketone formation has formed an unexpected oxidized peptide, with molecular mass 2 Da less than that expected, that is isolated for collision‐induced dissociation in the ion trap together with the predicted precursor due to the broad ion isolation window specified. Copyright © 2003 John Wiley & Sons, Ltd.
The ‘apparent’ hydrolysis of alkyl esters during electrospray ionization
Authors: Silvestri Maximilian A. , Miles Deborah , Rothwell Arlene P. , Wood Karl V. , Cushman Mark
Published: July 2003

Electrospray ionization (ESI) mass spectrometry was employed to obtain both molecular weight confirmation and structural information for a series of novel alkenyldiarylmethane (ADAM) analogs. The mass spectral data were intended for use during the structure elucidation of ester hydrolysis products formed during an in vitro metabolism study of a series of novel ADAM analogs. The data on the precursor molecules show the presence of the molecular ion peak, [M+H]+, as well as a peak consistent with the hydrolysis product of the original ester ([MH‐ROH+H2O]+). However, chemical ionization mass spectrometry, elemental analysis and 1H NMR data indicated the presence of only the intact diester compounds, suggesting that the formation of the hydrolysis product was an instrumental artifact, i.e., in‐beam hydrolysis during ESI or a result of longer ion residence times of the ion trap mass analyzer. Copyright © 2003 John Wiley & Sons, Ltd.
Workplace monitoring of isocyanates using ion trap liquid chromatography/tandem mass spectrometry
Authors: Vangronsveld Erik , Mandel Friedrich
Published: July 2003

A sensitive liquid chromatography/ion trap tandem mass spectrometry method was developed for the qualitative and quantitative detection of isocyanates in air. The method is based on derivatization of isocyanates with 1‐(2‐methoxyphenyl)piperazine during air sampling. The extracts are analyzed using an ion trap LC/MS system equipped with an electrospray (ESI) ion source. The method shows high linearity, specificity, accuracy and precision. The limits of detection are 40× to 55× lower than with UV‐based methods. Copyright © 2003 John Wiley & Sons, Ltd.
Characterization of Ganstigmine metabolites in hepatocytes by low‐ and high‐resolution mass spectrometry coupled with liquid chromatography
Authors: Pelizzi Nicola , Puccini Paola , Riccardi Benedetta , Acerbi Daniela , Catinella Silvia
Published: July 2003

In order to deepen the understanding of the metabolism of Ganstigmine, a new acetylcholinesterase inhibitor under evaluation for the treatment of Alzheimer's disease, samples obtained by incubating the drug with female rat hepatocytes were investigated by low‐resolution liquid chromatography/tandem mass spectrometry (LC/MS/MS). The results confirmed the formation of most of the phase I metabolites already demonstrated, but also three new species. The combination of high‐resolution quadrupole time‐of‐flight (Q‐TOF) LC/MS and LC/MS/MS measurements, and the evaluation of the more reasonable metabolic routes, allowed the identification of the new metabolites as Geneseroline‐glucuronide and oxidized and rearranged Ganstigmine. Analogous investigations were made using hepatocytes from male rat and dog, and both gender monkeys and humans, to compare the metabolic patterns. The results did not indicate substantial differences in terms of numbers and abundances of detected metabolites among the considered species, and also between male and female hepatocytes within each species. Copyright © 2003 John Wiley & Sons, Ltd.
Mass spectrometric studies of cyclopentanol derivatives in the reductive coupling of α,β‐unsaturated ketones assisted by samarium diiodide
Authors: Le Lagadec Ronan , Rubio Laura , Velasco Luis , Pérez‐Flores Javier , Miranda Rene , Cabrera Armando
Published: July 2003

The mass spectrometric fragmentations of a series of cyclopentanol derivatives in positive fast‐atom bombardment (FAB+) mode were investigated. The corresponding pathways proposed were confirmed by MS/MS data obtained using linked scans at constant B/E, high‐resolution accurate mass data, and comparisons with corresponding information for a specifically deuterated molecule. Copyright © 2003 John Wiley & Sons, Ltd.
Electrospray ionization from a droplet deposited on a surface‐modified glass rod
Authors: Jeng Jingyueh , Shiea Jentaie
Published: July 2003

This paper reports development of a non‐mechanical electrospray ionization (ESI) method to generate electrospray from a droplet deposited on an optical fiber coated with a thin gold or Nafion film. Modification of the surface of the optical fiber in this manner increases its wettability, such that a droplet of the aqueous sample solution can adhere sufficiently strongly to the tip of the fiber. The aqueous sample solution was deposited near the tip of the fiber with a micropipette. When a high voltage (2000 V) was applied to the fiber by electrical connection through the gold film, the sample solution moved and hung at the tip of the fiber. Simultaneously, ESI was generated from the sample droplet. Multiply charged peptide and protein ions were detected by connecting the ESI source to a quadrupole mass analyzer. Copyright © 2003 John Wiley & Sons, Ltd.
Selective solid‐phase isolation of methionine‐containing peptides and subsequent matrix‐assisted laser desorption/ionisation mass spectrometric detection of methionine‐ and of methionine‐sulfoxide‐containing peptides
Authors: Grunert Tom , Pock Katharina , Buchacher Andrea , Allmaier Günter
Published: July 2003

Methionine residues and the oxidised forms in proteins are becoming more and more important in view of their biological function. In particular, methionine sulfoxide seems to have a regulatory function. This paper presents a fast strategy for simultaneous determination of methionine‐ and methionine‐sulfoxide‐containing peptides, involving application of methionine‐specific solid‐phase reagent chemistry combined with matrix‐assisted laser desorption/ionisation mass spectrometry (MALDI‐MS). In the first step, methionine‐containing peptides are covalently bound as sulfonium salts to glass beads, whereas methionine‐sulfoxide‐containing peptides and other methionine‐free peptides are not bound and are washed out. The wash solution is used for MALDI‐MS analysis to determine the molecular masses of these peptides and to perform, if necessary, seamless post‐source decay (PSD) fragment ion analysis. Methionine‐sulfoxide‐containing peptides can be identified due to the characteristic metastable loss of methanesulfenic acid from the protonated molecules. In the second step, the bound peptides are cleaved from the matrix of the beads by addition of 2‐mercaptoethanol at pH 8.5–8.8. The resulting peptides, mainly methionine‐containing peptides, are analysed in a straightforward manner by MALDI‐MS and seamless PSD. The strategy allows the fast identification of methionine‐ and methionine‐sulfoxide‐containing peptides even in complex tryptic digests, as demonstrated here for the glycoprotein antithrombin. These results show that sometimes methionine‐containing tryptic peptides are not detected due to steric restrictions (e.g. glycosylation near the methionine residue) on the binding reaction, and that, on the other hand, some methionine‐free peptides can be quite strongly bound non‐covalently to the matrix of the beads. The latter observation indicates the necessity of seamless PSD fragment ion analysis for unambiguous identification. Furthermore, there are indications that oxidation of some methionine residues occurred to a minor extent during the solid‐phase isolation steps. Copyright © 2003 John Wiley & Sons, Ltd.