bluuebunny/crossref_metadata_2025_split huggingface dataset:
Classification of the caspase–hemoglobinase fold: Detection of new families and implications for the origin of the eukaryotic separins
Authors: Aravind L. , Koonin Eugene V. 
Published: September 2002

AbstractA comprehensive sequence and structural comparative analysis of the caspase–hemoglobinase protein fold resulted in the delineation of the minimal structural core of the protease domain and the identification of numerous, previously undetected members, including a new protease family typified by the HetF protein from the cyanobacterium Nostoc. The first bacterial homologs of legumains and hemoglobinases were also identified. Most proteins containing this fold are known or predicted to be active proteases, but multiple, independent inactivations were noticed in nearly all lineages. Together with the tendency of caspase‐related proteases to form intramolecular or intermolecular dimers, this suggests a widespread regulatory role for the inactive forms. A classification of the caspase–hemoglobinase fold was developed to reflect the inferred evolutionary relationships between the constituent protein families. Proteins containing this domain were so far detected almost exclusively in bacteria and eukaryotes. This analysis indicates that caspase–hemoglobinase‐fold proteases and their inactivated derivatives are widespread in diverse bacteria, particularly those with a complex development, such as Streptomyces, Anabaena, Mesorhizobium, and Myxococcus. The eukaryotic separin family was shown to be most closely related to the mainly prokaryotic HetF family. The phyletic patterns and evolutionary relationships between these proteins suggest that they probably were acquired by eukaryotes from bacteria during the primary, promitochondrial endosymbiosis. A similar scenario, supported by phylogenetic analysis, seems to apply to metacaspases and paracaspases, with the latter, perhaps, being acquired in an independent horizontal transfer to the eukaryotes. The acquisition of the caspase–hemoglobinase‐fold domains by eukaryotes might have been critical in the evolution of important eukaryotic processes, such as mitosis and programmed cell death. Proteins 2002;46:355–367. © 2002 Wiley‐Liss, Inc.
Interactions of Streptomyces griseus aminopeptidase with amino acid reaction products and their implications toward a catalytic mechanism
Authors: Gilboa R. , Spungin‐Bialik A. , Wohlfahrt G. , Schomburg D. , Blumberg S. , Shoham G. 
Published: September 2002

AbstractStreptomyces griseus aminopeptidase (SGAP) is a double‐zinc exopeptidase with a high preference toward large hydrophobic amino‐terminus residues. It is a monomer of a relatively low molecular weight (30 kDa), it is heat stable, it displays a high and efficient catalytic turnover, and its activity is modulated by calcium ions. The small size, high activity, and heat stability make SGAP a very attractive enzyme for various biotechnological applications, among which is the processing of recombinant DNA proteins and fusion protein products. Several free amino acids, such as phenylalanine, leucine, and methionine, were found to act as weak inhibitors of SGAP and hence were chosen for structural studies. These inhibitors can potentially be regarded as product analogs because one of the products obtained in a normal enzymatic reaction is the cleaved amino terminal amino acid of the substrate. The current study includes the X‐ray crystallographic analysis of the SGAP complexes with methionine (1.53 Å resolution), leucine (1.70 Å resolution), and phenylalanine (1.80 Å resolution). These three high‐resolution structures have been used to fully characterize the SGAP active site and to identify some of the functional groups of the enzyme that are involved in enzyme‐substrate and enzyme‐product interactions. A unique binding site for the terminal amine group of the substrate (including the side chains of Glu131 and Asp160, as well as the carbonyl group of Arg202) is indicated to play an important role in the binding and orientation of both the substrate and the product of the catalytic reaction. These studies also suggest that Glu131 and Tyr246 are directly involved in the catalytic mechanism of the enzyme. Both of these residues seem to be important for substrate binding and orientation, as well as the stabilization of the tetrahedral transition state of the enzyme‐substrate complex. Glu131 is specifically suggested to function as a general base during catalysis by promoting the nucleophilic attack of the zinc‐bound water/hydroxide on the substrate carbonyl carbon. The structures of the three SGAP complexes are compared with recent structures of three related aminopeptidases: Aeromonas proteolytica aminopeptidase (AAP), leucine aminopeptidase (LAP), and methionine aminopeptidase (MAP) and their complexes with corresponding inhibitors and analogs. These structural results have been used for the simulation of several species along the reaction coordinate and for the suggestion of a general scheme for the proteolytic reaction catalyzed by SGAP. Proteins 2001;44:490–504. © 2001 Wiley‐Liss, Inc.
Automated assignment of SCOP and CATH protein structure classifications from FSSP scores
Authors: Getz Gad , Vendruscolo Michele , Sachs David , Domany Eytan 
Published: September 2002

AbstractWe present an automated procedure to assign CATH and SCOP classifications to proteins whose FSSP score is available. CATH classification is assigned down to the topology level, and SCOP classification is assigned to the fold level. Because the FSSP database is updated weekly, this method makes it possible to update also CATH and SCOP with the same frequency. Our predictions have a nearly perfect success rate when ambiguous cases are discarded. These ambiguous cases are intrinsic in any protein structure classification that relies on structural information alone. Hence, we introduce the “twilight zone for structure classification.” We further suggest that to resolve these ambiguous cases, other criteria of classification, based also on information about sequence and function, must be used. Proteins 2002;46:405–415. © 2002 Wiley‐Liss, Inc.
Recombinant baculoviruses for insect control
Authors: Inceoglu Ahmet B , Kamita Shizuo G , Hinton Andrew C , Huang Qihong , Severson Tonya F , Kang Kyung‐don , Hammock Bruce D 
Published: September 2002

AbstractBaculoviruses are double‐stranded DNA viruses which are highly selective for several insect groups. They are valuable natural control agents, but their utility in many agricultural applications has been limited by their slow speed of kill and narrow host specificity. Baculoviruses have been genetically modified to express foreign genes under powerful promoters in order to accelerate their speed of kill. In our and other laboratories, the expression of genes coding for insect juvenile hormone esterases and various peptide neurotoxins has resulted in recombinant baculoviruses with promise as biological insecticides. These viruses are efficacious in the laboratory, greenhouse and field and dramatically reduce damage caused by insect feeding. The recombinant viruses synergize and are synergized by classical pesticides such as pyrethroids. Since they are highly selective for pest insects, they can be used without disrupting biological control. Because the recombinant virus produces fewer progeny in infected larvae than the wild‐type virus, they are rapidly out‐competed in the ecosystem. The viruses can be used effectively with crops expressing endotoxins of Bacillus thuringiensis. They can be produced industrially but also by village industries, indicating that they have the potential to deliver sustainable pest control in developing countries. It remains to be seen, however, whether the current generation of recombinant baculoviruses will be competitive with the new generation of synthetic chemical pesticides. Current research clearly indicates, though, that the use of biological vectors of genes for insect control will find a place in agriculture. Baculoviruses will also prove valuable in testing the potential utility of proteins and peptides for insect control.© 2001 Society of Chemical Industry
Toxicity of biorational insecticides: activity against the green peach aphid, Myzus persicae (Sulzer)
Authors: Edelson Jonathan V , Duthie J , Roberts W 
Published: September 2002

AbstractThe relationship between dose for each of four biorational insecticides (pyrethrins, neem extract, capsiacin extract, insecticidal soap) and mortality of the green peach aphid (Myzus persicae) was determined using a laboratory bioassay. These insecticides were toxic to aphids and paired mixtures of the insecticides provided synergistic activity as measured by aphid mortality under the laboratory bioassay conditions. Capsiacin extracts were found to provide low levels of mortality alone but acted synergistically in mixtures with the other insecticides and provided higher than expected levels of mortality. Activity as determined in the laboratory for each insecticide was not evident under field‐use conditions in five separate experiments. Under field conditions and using common application methods, these insecticides did not provide significant levels of control of aphids.© 2002 Society of Chemical Industry
Insecticidal 2‐hydroxy‐3‐alkyl‐1,4‐naphthoquinones: correlation of inhibition of ubiquinol cytochrome c oxidoreductase (complex III) with insecticidal activity
Authors: Jewess Philip J , Chamberlain Keith , Boogaard Adrian B , Devonshire Alan L , Khambay Bhupinder P S 
Published: September 2002

AbstractThe insecticidal and in vitro activities of four homologous series of 2‐hydroxy and acetoxy‐3‐substituted‐1,4‐naphthoquinones have been measured and correlated with their (Log) octanol/water partition coefficients (Log Ko/w). In vitro activity against mitochondrial complex III was only exhibited by 2‐hydroxy‐3‐alkyl‐1,4‐naphthoquinones, indicating that the 2‐acetoxy compounds act as pro‐insecticides. Good correlation was observed between in vivo activity against the two‐spotted spider mite, Tetranychus urticae and inhibition of complex III isolated from blowfly flight muscle. Both hydroxy and acetoxy analogues of individual compounds exhibited similar levels of in vivo activity with optimum activity for analogues with Log Ko/w values of 7–8. In contrast, the acetoxy derivatives showed superior in vivo activity against the tobacco whitefly, Bemisia tabaci. Complex III isolated from whitefly was optimally inhibited by hydroxy analogues with lower Log Ko/w values (6.0–6.5) and was also more sensitive than the blowfly enzyme to all the compounds tested.© 2002 Society of Chemical Industry
The response of phosphine‐resistant lesser grain borer Rhyzopertha dominica and rice weevil Sitophilus oryzae in mixed‐age cultures to varying concentrations of phosphine
Authors: Rajendran Somiahnadar , Gunasekaran Nagamuthu 
Published: September 2002

AbstractThe response of Rhyzopertha dominica and Sitophilus oryzae (both phosphine‐resistant) in mixed‐age cultures to phosphine at fixed concentration–time products (CT) of 10 500 to 168 000 µl litre−1 h (ppm h) with either constant, rising or falling concentrations for 7 days was studied at 27(±2) °C. At lower CT products, rising concentrations of phosphine led to significantly fewer survivors of R dominica and S oryzae. Conversely, exposure to falling concentrations of phosphine resulted in significantly more survivors. The influence of changing concentrations of phosphine was more pronounced in S oryzae than in R dominica. In the latter, at the lower CT products of 21 000 and 42 000 µl litre−1 h, the adult stage proved to be most tolerant, contrary to the accepted belief that the egg or pupal stage are always more tolerant to phosphine. The results indicate that application of phosphine in rising concentrations is more effective than in constant or falling concentrations.© 2002 Society of Chemical Industry
Potential of a novel antibiotic, 2‐methylheptyl isonicotinate, as a biocontrol agent against fusarial wilt of crucifers
Authors: Bordoloi Gojen N , Kumari Babita , Guha Arijit , Thakur Debajit , Bordoloi Manabjyoti , Roy Monoj K , Bora Tarun C 
Published: September 2002

AbstractScreening for newer bioactive compounds from microbial metabolites resulted in the isolation of a novel antibiotic from the culture filtrate, Streptomyces sp 201, of a soil. The bioactive compound, with antifungal and antibacterial activity, was identified as 2‐methylheptyl isonicotinate. The antifungal activity of live culture, culture broth and the isolated bioactive compound showed marked inhibition against dominant soil‐borne phytopathogens such as Fusarium oxysporum Schlect, F moniliforme Sheldon, F semitectum Berkeley & Ravenel, F solani (Martius) Sacc and Rhizoctonia solani Kuehn. The compound had no effect on seed germination and seedling development as displayed by root and stem growth of the test plant species. In pot experiments with seedlings of cruciferous plants such as Raphanus sativus L (radish), Brassica campestris L (yellow mustard), Brassica oleracea var botrytis L (cauliflower), the antibiotic compound showed promising protective activity of 92% when seeds of the test plants were treated at a dose of 50 µgml−1 prior to sowing. Seed treatment with a spore suspension (3 × 108 spores ml−1) of the Streptomyces sp 201 displayed protective activity in the range of 56–60%. Seeds coated with 2.5% methyl cellulose‐amended spores of the antagonist showed protective activity in the range of 64–72%. Further, seed treatment with the culture filtrate of the antagonist also showed promising protective activity in the range of 64–84%.© 2002 Society of Chemical Industry
In vivo and in vitro metabolism of fipronil by larvae of the European corn borer Ostrinia nubilalis
Authors: Durham Eric W , Siegfried Blair D , Scharf Michael E 
Published: September 2002

AbstractIn vivo and in vitro metabolism of [14C]fipronil was examined in a susceptible European corn borer (Ostrinia nubilalis, Hübner) laboratory strain. [14C]Fipronil penetrated the larval integument slowly, with 71.5% of the applied radioactivity recovered from surface rinses 24 h after topical application. Despite this slow penetration, radioactivity was detected in both the excrement and internal organo‐soluble fractions. Radioactivity in the internal aqueous fraction and tissue pellet accounted for less than 0.8% of total radioactivity. The in vivo studies suggest that fipronil oxidation to its sulfone metabolite is the major route of metabolic conversion. In vitro studies were performed using subcellular microsomal fractions isolated from European corn borer larval midguts. Cytochrome P450‐dependent monooxygenase activity (methoxyresorufin O‐demethylase) was consistently observed in midgut preparations, and formation and detection of the sulfone metabolite in the same midgut preparations was also NADPH‐dependent and inhibited by piperonyl butoxide. In vitro metabolism results indicate microsomal monooxygenases are responsible for the conversion of fipronil to its sulfone form in the European corn borer.© 2002 Society of Chemical Industry
Assessment of relevant factors and relationships concerning human dermal exposure to pesticides in greenhouse applications
Authors: Martínez Vidal Jose L , González Francisco J Egea , Frenich Antonia Garrido , Galera María Martínez , Aguilera Pedro A , Carrique Enrique López 
Published: September 2002

AbstractPrincipal component analysis (PCA) was applied to the gas chromatographic data obtained from 23 different greenhouse trials. This was used to establish which factors, including application technique (very small, small, medium and large drop‐size), crop characteristics (short/tall, thin/dense) and pattern application of the operator (walking towards or away from the treated area) are relevant to the dermal exposure levels of greenhouse applicators. The results showed that the highest exposure by pesticides during field applications in greenhouses, in the climatic conditions and in the crop conditions typical of a southern European country, occurs on the lower legs and front thighs of the applicators. Similar results were obtained by hierarchical cluster analysis (HCA). Drop‐size seems to be very important in determining total exposure, while height and density of crops have little influence on total exposure under the conditions of the present study. No pesticide type is a major factor in total exposure. The application of multiple regression analysis (MRA) allowed assessment of the relationships between the pesticide exposure of the less affected parts of the body with the most affected parts.© 2002 Society of Chemical Industry
Calibration of pesticide leaching models: critical review and guidance for reporting
Authors: Dubus Igor G , Beulke Sabine , Brown Colin D 
Published: September 2002

AbstractCalibration of pesticide leaching models may be undertaken to evaluate the ability of models to simulate experimental data, to assist in their parameterisation where values for input parameters are difficult to determine experimentally, to determine values for specific model inputs (eg sorption and degradation parameters) and to allow extrapolations to be carried out. Although calibration of leaching models is a critical phase in the assessment of pesticide exposure, lack of guidance means that calibration procedures default to the modeller. This may result in different calibration and extrapolation results for different individuals depending on the procedures used, and thus may influence decisions regarding the placement of crop‐protection products on the market. A number of issues are discussed in this paper including data requirements and assessment of data quality, the selection of a model and parameters for performing calibration, the use of automated calibration techniques as opposed to more traditional trial‐and‐error approaches, difficulties in the comparison of simulated and measured data, differences in calibration procedures, and the assessment of parameter values derived by calibration. Guidelines for the reporting of calibration activities within the scope of pesticide registration are proposed.© 2002 Society of Chemical Industry
Laboratory evaluation of two novel strategies to control first‐instar gypsy moth larvae with spinosad applied to tree trunks
Authors: Wanner Kevin W , Helson Blair V , Harris Brenda J 
Published: September 2002

AbstractTwo strategies for controlling first‐instar larvae of gypsy moth (Lymantria dispar (L)), insecticidal bait and contact insecticide applied directly to the tree trunk, were evaluated in the laboratory. Spinosad was selected as a candidate natural‐product insecticide that is active both by contact and ingestion. Incorporated into artificial diet‐based bait, spinosad was toxic to neonate larvae with a minimal 10‐s feeding period, with an LC50 value of 20 (15–26, 95% confidence interval) mg liter−1. It was significant that neonate larvae did not discriminate between spinosad‐treated and control diet. Efficacy of diet‐based bait in the laboratory, however, was significantly impacted by previous exposure to diet; fed larvae did not stop at the bait and did not incur mortality, as compared to unfed larvae. Oak bark was a suitable substrate from which neonate larvae could contact spinosad residues. Spinosad applied directly to oak bark resulted in significant mortality after 1‐ and 4‐min crawling contact exposure times (LC50 = 24 [20–29, 95% CI] and 8.7 [6.9–11, 95% CI] mg liter−1, respectively) and contact activity persisted for 2 weeks. While contact activity was more potent on glass surfaces than on oak bark, the LC50 values differed only by factors of 2.4 and 3.6, for 1‐ and 4‐min exposures respectively.© 2002 Society of Chemical Industry
Photochemical behaviour of dichlorprop [(±)‐2‐(2,4‐dichlorophenoxy)propanoic acid] in aqueous solution
Authors: Meunier Laurence , Gauvin Emmanuelle , Boule Pierre 
Published: September 2002

AbstractAqueous solutions of dichlorprop were irradiated under different conditions of pH, wavelength and oxygenation. The photochemical behaviour was found to be complex and many photoproducts were formed. However, at low concentrations the main photoproducts were 4‐chloropyrocatechol, 2‐chlorophenol, 4‐chlorophenol and 2,4‐dichlorophenol. Some other photoproducts were identified, namely 2‐(4‐chloro‐2‐hydroxyphenoxy)propanoic acid, 2‐(3,5‐dichloro‐2‐hydroxyphenyl)propanoic acid and 2,4‐dichlorophenyl acetate. From comparison with results previously obtained with mecoprop [2‐(4‐chloro‐2‐methylphenoxy)propanoic acid] it appears that the presence of a chlorine atom in position 2 on the ring strongly modifies the photochemical behaviour.© 2002 Society of Chemical Industry
Haptenization of ovalbumin with the skin sensitizer methyl octanesulfonate: Characterization of the methylated OVA323‐339 T‐cell epitope at His331
Authors: Henriot Stéphanie , Lepoittevin Jean‐Pierre , Trifilieff Elisabeth 
Published: September 2002

AbstractOur interest is focused on the induction of allergic contact dermatitis (ACD) by the strong skin sensitizer, methyl octanesulfonate, which is a potent methyl transfer agent, especially to histidine and methionine residues. We are particularly interested to study the effect of methylation on the presentation and recognition of the ovalbumin (OVA) T‐cell epitope, OVA323‐339, by the T‐cell receptor (TCR). Here we report the synthesis of the modified monomer N‐α‐Fmoc‐N‐τ‐methyl‐𝓁‐histidine and its incorporation by solid phase synthesis into the three possible methylated analogues of OVA323‐339, that were needed as references for the subsequent studies. Native OVA was haptenized by methyl octanesulfonate. Using classical protein chemistry techniques (trypsin digestion, gel permeation, HPLC, MS and Edman sequencing) we were able to show that OVA323‐339 was selectively methylated at His331. Circular dichroism (CD) studies showed that the methylation has no influence on the secondary structure of the peptide. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
High yield synthesis of tentoxin, a cyclic tetrapeptide
Authors: Loiseau Nicolas , Cavelier Florine , Noel Jean‐Pierre , Gomis Jean‐Marie 
Published: September 2002

AbstractTentoxin is a naturally occurring phytotoxic cyclic tetrapeptide excreted by fungi of the Alternaria alternata family. The four total syntheses of tentoxin published to date give poor total yields, mainly owing to two difficulties, the introduction of the dehydro amino acid and more especially the cyclization step. Here we describe a method that stereospecifically introduces Z‐dehydrophenylalanine (ΔZPhe) by a modified Erlenmeyer aldolization reaction. The linear tetrapeptide, Boc‐R1Ala‐Leu‐R2ΔZPhe‐Gly‐OMe (R1, R2: CH3, 14CH3), the precursor of tentoxin, was obtained in a 72% yield from Boc‐Leu‐Gly‐OH. This linear tetrapeptide, labelled with carbon‐14, was used for a comparative study of four cyclization reagents DPPA, DCC–PfpOH, HBTU and HATU. This last was the most effective and gave tentoxin in a 81% cyclization yield. The activated ester formed with this reagent displayed an enhanced capacity for cyclization, permitting cyclization in concentrated medium (10 mM). This new synthetic route gave tentoxin in a 60% yield from Boc‐Leu‐Gly‐OH and offers a means of achieving the synthesis of hitherto elusive analogues. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.