bluuebunny/crossref_metadata_2025_split huggingface dataset:
Local and systemic effects of oxylipins on powdery mildew infection in barley
Authors: Cowley Tracy , Walters Dale 
Published: January 2005

AbstractTreatment of the first leaves of barley seedlings with the oxylipin colneleic acid, or the two trihydroxy oxylipins 9,12,13‐trihydroxy‐11(E)‐octadecenoic acid and 9,12,13‐trihydroxy‐10(E)‐octadecenoic acid, reduced infection of that leaf by the powdery mildew fungus Blumeria graminis Speer f sp hordei Marchal. When applied to first leaves, etheroleic acid and colneleic acid, as well as the trihydroxy oxylipin 9,12,13‐trihydroxy‐10(E),15(Z)‐octadecadienoic acid, also reduced mildew infection in second leaves. In all cases where local and systemic effects against mildew were observed, activity of the defence‐related enzyme phenylalanine ammonia lyase (PAL) was increased, but only following challenge inoculation with powdery mildew. Peroxidase activity was not affected by oxylipin treatment or mildew inoculation. Whether the effects observed were due to the oxylipins or to breakdown products is not known, since no information is available on the stability of these particular oxylipins on leaf surfaces. Nevertheless, these data represent the first report of systemic effects against pathogen infection following pre‐treatment with oxylipins. Copyright © 2005 Society of Chemical Industry
Translocation and translaminar bioavailability of two neonicotinoid insecticides after foliar application to cabbage and cotton
Authors: Buchholz Anke , Nauen Ralf 
Published: January 2005

AbstractA laboratory study was undertaken to investigate the leaf systemic properties and the translaminar aphicidal activity of two commercialised neonicotinoid (chloronicotinyl) insecticides. For that purpose [14C]imidacloprid was subjected to uptake and translocation studies in cabbage and cotton after foliar application. Foliar penetration and short‐term translocation patterns of imidacloprid were similar in both plant species. Nevertheless imidacloprid penetrated twice as much into cabbage leaves as it did into cotton leaves. It showed a comparable translaminar behaviour and was entirely translocated acropetally, indicating its well‐known xylem mobility. The translaminar and acropetal movement of imidacloprid and acetamiprid were quantified by simple laboratory bioassays using the green peach aphid, Myzus persicae (Sulzer), and the cotton aphid, Aphis gossypii (Glover), as typical homopteran pests for cabbage and cotton, respectively. A single dose (7.5 µg AI per leaf) applied to the upper leaf surface of cabbage and cotton was tested against aphids feeding on the lower leaf surface both close to and distant from the site of application 1, 5 and 12 days after treatment. The translaminar residual activity of imidacloprid on cabbage leaves was superior to that of acetamiprid, whereas its translaminar efficacy against A gossypii on cotton was inferior to that of acetamiprid. However, oral ingestion bioassays using an artificial double membrane feeding system revealed no significant differences in intrinsic activity between the two neonicotinoids tested.© 2001 Society of Chemical Industry
Spatial variability in herbicide degradation in the subsurface environment of a groundwater protection zone
Authors: Wood Martin , Issa Salah , Albuquerque Miriam , Johnson Andrew C 
Published: January 2005

AbstractThe aim of this study was to investigate the spatial variability in degradation and mineralization of atrazine and isoproturon in subsurface samples taken from sandy loam soils overlying gravel terraces which form part of a groundwater protection zone. Percussion drilling was used to obtain samples from 11 boreholes (maximum depth 3 m). Unlabelled atrazine or isoproturon, and ring‐14C‐labelled atrazine or isoproturon were added to samples, incubated at 25 °C for up to 16 weeks, and analyzed for the residual herbicide or [14C]carbon dioxide. All samples showed the potential to degrade these herbicides, although the percentage degradation decreased by a factor of 2–3 from the surface soil to a depth of 3 m. This was associated with a decrease in organic matter content, but there was no change in the potential to mineralize acetate, indicating that specific changes in the catabolic ability of the microbial population occurred with depth. The capacity of samples to mineralize atrazine and isoproturon to carbon dioxide decreased markedly with depth, with no mineralization potential observed at a depth of 80 cm.© 2001 Society of Chemical Industry
The effect of foliar application of phosphonate formulations on the susceptibility of potato tubers to late blight
Authors: Cooke Louise R , Little George 
Published: January 2005

AbstractFoliar sprays of potato plants with phosphonic acid (partially neutralised with potassium hydroxide to pH 6.4) substantially reduced infection of the tubers by Phytophthora infestans, the cause of late blight, in glasshouse and field experiments over a 4‐year period. Healthy tubers of blight‐susceptible cultivars removed from treated plants and artificially inoculated by spraying with sporangial/zoospore suspensions of P infestans did not develop disease symptoms, demonstrating that the phosphonate applications had directly reduced the susceptibility of tubers to infection, probably as a result of translocation into tuber tissue. In contrast, foliar application of fosetyl‐aluminium did not significantly reduce tuber blight development following inoculation. Five to six sprays of partially neutralised phosphonic acid (2 kg ha−1) applied at 10–14 day intervals resulted in the least tuber infection, but such a treatment regime may not be economic. In trials where the effect of timing and rate of application of 2–4 kg phosphonic acid ha−1 was examined, a single treatment of 4 kg ha−1 applied mid‐ or late‐season proved the most effective. A spray programme in which one or two applications of phosphonic acid are combined with use of a non‐systemic or systemic fungicide to enhance foliar protection offers the possibility of controlling both foliage and tuber blight and could have a major impact in reducing overwinter survival of P infestans in tubers.© 2001 Society of Chemical Industry
New, quick tests for herbicide resistance in black‐grass (Alopecurus myosuroides Huds) based on increased glutathione S‐transferase activity and abundance
Authors: Reade John P H , Cobb Andrew H 
Published: January 2005

AbstractBlack‐grass (Alopecurus myosuroides Huds) is a major grass weed in winter cereals in Europe. It reduces yields and can act as a secondary host for a range of diseases. Herbicide resistance in this species was first detected in the UK in the early 1980s, and has now been reported in thirty counties. To successfully manage herbicide resistance it is vital that suspect populations are tested so that appropriate action can be taken. Ideally, a test will be quick, cheap and easy to use. Furthermore, it should provide an unequivocal result before post‐emergence herbicides are to be applied, allowing alternative strategies to be adopted where necessary. This paper reports the development of new tests for herbicide resistance based on our observation that the resistant black‐grass biotype Peldon contains approximately double the activity of the enzyme glutathione S‐transferase (GST) compared with susceptible biotypes. Data are presented on the production of a monoclonal antiserum to a novel 30 kDa GST polypeptide purified from the biotype Peldon. An ELISA using this antiserum is described and the utility of this assay to detect resistant black‐grass biotypes in plants grown under glass and in the field is presented. In addition, a microtitre assay for GST activity is described, which allows the rapid assessment of GST activities of plants. Both abundance and activity of GSTs are discussed as markers for herbicide resistance in black‐grass.© 2001 Society of Chemical Industry
Antimicrobial and pesticidal activity of partially purified flavonoids of Annona squamosa
Authors: Kotkar Hemlata M , Mendki Prashant S , Sadan Sangeetha V G S , Jha Shipra R , Upasani Shripad M , Maheshwari Vijay L 
Published: January 2005

AbstractFoliar extracts of Annona squamosa (Family: Annonaceae) were screened for antimicrobial and insecticidal activity against the common microbial infestants of pulses and the stored grain pest pulse beetle, Callosobruchus chinensis (Coleoptera: Bruchidae). Flavonoids isolated from aqueous extracts of A squamosa showed antimicrobial activity against all the common microbial contaminants of pulses and 80% insecticidal activity against C chinensis at a concentration of 0.07 mg ml−1. Various physico‐chemical tests, chromatographic and spectroscopic studies with partially purified aqueous extract indicated the presence of flavonol type flavonoids. This may provide a useful beginning for the development of botanical pesticides for post‐harvest safeguard of pulses.© 2001 Society of Chemical Industry
Herbicidal action of 2‐hydroxy‐3‐alkyl‐1,4‐naphthoquinones
Authors: Jewess Philip J , Higgins James , Berry Kate J , Moss Stephen R , Boogaard Adrian B , Khambay Bhupinder P S 
Published: January 2005

AbstractThe main mode of herbicidal activity of 2‐hydroxy‐3‐alkyl‐1,4‐naphthoquinones is shown to be inhibition of photosystem II (PSII). The herbicidal andin vitroactivities have been measured and correlated with their (Log)octanol/water partition coefficients (LogKo/w). The length of the 3‐n‐alkyl substituent for optimal activity differed between herbicidal andin vitroactivity. The maximumin vitroactivity was given by the nonyl to dodecyl homologues (LogKo/wbetween 6.54 and 8.12), whereas herbicidal activity peaked with then‐hexyl compound (LogKo/w = 4.95). The effect of chain branching was also investigated using isomeric pentyl analogues substituted at position 3. All exhibited similar levels ofin vitroactivities but herbicidal activities differed, albeit moderately, with the exception of one analogue that was much less phytotoxic. Other modes of action were also investigated using two representative compounds. They did not show any activity on photosystem I or mitochondrial complex I, or generate toxic oxygen radicals by redox cycling reactions. Only moderate activity was found against mitochondrial complex III from plants, in contrast to much higher corresponding activity using an insect enzyme.© 2002 Society of Chemical Industry
Cotton whitefly (Bemisia tabaci) resistance to organophosphate and pyrethroid insecticides in Pakistan
Authors: Ahmad Mushtaq , Arif M Iqbal , Ahmad Zahoor , Denholm Ian 
Published: January 2005

AbstractResistance to three organophosphate and four pyrethroid insecticides was monitored from 1992 to 2000 in field populations of adult whiteflies, Bemisia tabaci, from Pakistan using a leaf‐dip method. There was generally a very high resistance to dimethoate and deltamethrin, and a moderate resistance to monocrotophos during 1992 to 1996. From 1997 to 2000, resistance to these insecticides dropped to low levels because of less reliance on them for whitefly control, and introduction of new chemistries with novel modes of action that had no cross‐resistance to conventional insecticides. Concurrently, whitefly resistance to acephate, fenpropathrin, lambda‐cyhalothrin and bifenthrin mostly remained low. An insecticide resistance management strategy is recommended that particularly emphasizes the rotation of still‐effective insecticides from different chemical classes along with the use of novel chemicals and other tactics of integrated pest management.© 2001 Society of Chemical Industry
Effect of cropping cycles and repeated herbicide applications on the degradation of diclofop‐methyl, bentazone, diuron, isoproturon and pendimethalin in soil
Authors: Piutti Séverine , Marchand Anne‐Laure , Lagacherie Bernard , Martin‐Laurent Fabrice , Soulas Guy 
Published: January 2005

AbstractA greenhouse study was conducted to investigate the ability of four crops (wheat, corn, oilseed rape and soybean) to influence the degradation of bentazone, diclofop‐methyl, diuron, isoproturon and pendimethalin in soil. The present study showed that microbial biomass‐carbon was significantly higher in planted soils than in bulk soil, especially with wheat and corn, after several cropping cycles. The biomass in corn and soybean planted soils was adversely affected by bentazone but recovered after three cropping cycles. In wheat‐planted soils, diclofop‐methyl application resulted in persistent increase of the amount of microbial biomass. Bentazone did not show accelerated degradation even after five successive treatments, differing from diclofop‐methyl, for which two applications were sufficient to enhance significantly its rate of degradation. Enhanced degradation of diclofop‐methyl was even more pronounced in wheat‐planted soil. The rates of mineralisation of diuron, isoproturon and pendimethalin were not affected after the first cropping cycle, but were significantly increased in planted soils after five cropping cycles. The results confirm that plants may promote pesticide degradation in soil by stimulating biodegradation processes. In the case of diclofop‐methyl, stimulation of accelerated degradation was observed.© 2002 Society of Chemical Industry
Adsorption–desorption studies of alachlor, metolachlor, EPTC, chlorothalonil and pirimiphos‐methyl in contrasting soils
Authors: Patakioutas Georgios , Albanis Triantafyllos A 
Published: January 2005

AbstractFive soils with different organic matter contents ranging from 0.48 to 10.4% were used to study the adsorption and desorption of alachlor, metolachor, EPTC, chlorothalonil and pirimiphos‐methyl in batch experiments. The isotherm shapes according to Giles classification were S‐type for alachlor, metolachlor and chlorothalonil, changing to L‐type for the latter as the level of soil organic matter increased, and L‐type for EPTC and pirimiphos‐methyl. The adsorption isotherms fitted the Freundlich equation x/m = KfCe1/n. The Kf values increased with the increase of organic matter content. The amounts of pesticides adsorbed over a range of concentrations of 0.1–20 mg litre−1 reached 63.1% for alachlor, 69.2% for metolachlor, 89.3% for EPTC, 98.4% for chlorothalonil and 96.3% for pirimiphos‐methyl. The increase of the amounts desorbed with acetone indicated that the sorption of organic compounds onto organic matter occurred principally via weak London‐type induction forces, or dispersion forces which are characteristics of the physical adsorption process.© 2002 Society of Chemical Industry
Characterization of Polypeptide Antibiotics of the Polymyxin Series by Liquid Chromatography Electrospray Ionization Ion Trap Tandem Mass Spectrometry
Authors: Govaerts Cindy , Orwa Jennifer , Schepdael Ann Van , Roets Eugène , Hoogmartens Jos 
Published: January 2005

AbstractA selective reversed phase liquid chromatography/mass spectrometry (LC/MSn) method is described for the identification of related compounds in commercial polymyxin B samples. Mass spectral data for these polypeptide antibiotics were acquired on a LCQ ion trap mass spectrometer equipped with an electrospray ionization probe operated in the positive ion mode. The LCQ ion trap is ideally suited for the identification of the related substances because it provides on‐line LC/MSn capability. The main advantage of this hyphenated LC/MSn technique is the characterization of novel related substances without time‐consuming isolation and purification procedures. Using this method six novel related substances were partially identified in a polymyxin B bulk sample. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
Conformational investigations on glycosylated asparagine‐oligopeptides of increasing chain length
Authors: Biondi Laura , Filira Fernando , Gobbo Marina , Rocchi Raniero 
Published: January 2005

AbstractStepwise solution syntheses of the homo‐oligomers Boc‐(Asn)n‐NHCH3 (n = 1–5; I1–5), Boc‐{[GlcNAc(Ac)3β]Asn}n‐NHCH3 (n = 1–8; II1–8), and Boc‐[(GlcNAcβ)Asn]n‐NHCH3 (n = 1–8; III1–8) are described. Members of the series III were obtained by deacetylation of the corresponding members of the series II. The conformational preferences of the N‐protected homo‐peptides of the three series were investigated by spectroscopic techniques. 1H‐NMR measurements were carried out in various solvents; the CD spectra were recorded in water, aqueous SDS and TFE. The poor solubility of the oligomers of the three series prevented FT‐IR measurements in solution. NMR and IR measurements indicate the existence of unordered structures containing some γ‐turns in the carbohydrate‐free oligomers and the presence of β‐turns in the glycosylated oligopeptides, whether acetylated or not. The CD spectra do not indicate the presence of organized structures. The sugar moieties apparently do not have a structure‐inducing effect on the asparagine homo‐oligomer main chain. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
Probing structural requirements of fMLP receptor: On the size of the hydrophobic pocket corresponding to residue 2 of the tripeptide
Authors: Spisani Susanna , Traniello Serena , Cavicchioni Giorgio , Formaggio Fernando , Crisma Marco , Toniolo Claudio 
Published: January 2005

AbstractThe conformationally constrained f‐L‐Met‐Acnc‐L‐Phe‐OMe (n = 4,9–12) tripeptides, analogues of the chemoattractant f‐L‐Met‐L‐Leu‐L‐Phe‐OH, were synthesized in solution by classical methods and fully characterized. These compounds and the published f‐L‐Met‐Xxx‐L‐Phe‐OMe (Xxx = Aib and Acnc where n = 3, 5–8) analogues were compared to determine the combined effect of backbone preferred conformation and side‐chain bulkiness at position 2 on the relation of 3D‐structure to biological activity. A conformational study of all the analogues was performed in solution by FT‐IR absorption and 1H‐NMR techniques. In parallel, each peptide was tested for its ability to induce chemotaxis, superoxide anion production and lysozyme secretion from human neutrophils. The biological and conformational data are discussed in relation to the proposed model of the chemotactic receptor on neutrophils, in particular of the hydrophobic pocket accommodating residue 2 of the tripeptide. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
Structural motifs in the maturation process of peptide hormones. The somatostatin precursor. I. A CD conformational study
Authors: Simonetti Mario , Di Bello Carlo 
Published: January 2005

AbstractSynthetic peptides reproducing both the native domain around the dibasic cleavage site of pro‐somatostatin, and mutated sequences thereof, previously assayed in site‐directed mutagenesis experiments, have been studied by CD in different solvent systems, such as water, TFE/H2O, MeCN/H2O and aqueous SDS, in order to ascertain the ability of each solvent to stabilize secondary structural motifs. A combination of deconvolution methods and empirical calculations, that allow subtraction of the contributions due to unordered structures from the spectra, suggests that mainly two distinct families of ordered conformers containing α‐helix and/or structurally different β‐turns are present in solution, the relative stability of the different conformers depending on the nature of the solvent. The presence of β‐turns is in line with a previous NMR study in DMSO and DMSO/H2O. Comparison of the CD spectra in aqueous SDS of peptides undergoing processing with a sequence not processed in vivo shows that only the latter possesses a stable and detectable α‐helix population. This observation suggests that the structuration involving β‐turns but no α‐helix, which was observed by CD both in SDS and organic solvent/H2O mixtures at high water contents, might be of biological significance. The similarity of this structuration to molecular models obtained from NMR data in DMSO and DMSO/H2O is discussed. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
Intestinal Transport of the Lactokinin Ala‐Leu‐Pro‐Met‐His‐Ile‐Arg through a Caco‐2 Bbe Monolayer
Authors: Vermeirssen V. , Deplancke B. , Tappenden K. A. , Camp J. Van , Gaskins H. R. , Verstraete W. 
Published: January 2005

AbstractACE inhibitory peptides are biologically active peptides that play a role in blood pressure regulation. When derived from food proteins during food processing or gastrointestinal digestion, these peptides could function as efficient agents in treating and preventing hypertension. However, in order to exert an antihypertensive effect by inhibition of the ACE enzyme, they have to reach the bloodstream intact. The aim of this research was to assess if the known ACE inhibitory peptide Ala‐Leu‐Pro‐Met‐His‐Ile‐Arg, derived from a tryptic digest of β‐lactoglobulin, could be absorbed through a Caco‐2 Bbe cell monolayer in an Ussing chamber and reach the serosal side undegraded. Samples of the mucosal compartment showed high ACE inhibitory activity. No or only little ACE inhibitory activity was detected in the serosal compartment. However, when the serosal sample was concentrated three‐fold, a substantial ACE inhibitory activity was registered. Concomitantly, HPLC and MS clearly showed the presence of Ala‐Leu‐Pro‐Met‐His‐Ile‐Arg in the mucosal compartment, whereas in the serosal compartment only MS was able to detect the heptapeptide. In conclusion, under the observed experimental conditions, the ACE inhibitory peptide Ala‐Leu‐Pro‐Met‐His‐Ile‐Arg was transported intact through the Caco‐2 Bbe monolayer, but in concentrations too low to exert an ACE inhibitory activity. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
Purification of Angularin, A Novel Antifungal Peptide from Adzuki Beans
Authors: Ye X. Y. , Ng T. B. 
Published: January 2005

AbstractAn antifungal peptide was isolated from the adzuki bean with a procedure involving affinity chromatography on Affi‐gel blue gel and ion exchange chromatography on CM‐Sepharose. The protein designated angularin was adsorbed on both types of chromatographic media and possessed a molecular weight of 8 kDa. Angularin exhibited antifungal activity against a variety of fungal species including Mycospharella arachidiocola and Botrytis cinerea. It inhibited mycelial growth in B. cinerea with an IC50 of 14.3 µM. Fusarium oxysporum and Rhizoctonia solani were not inhibited. Angularin demonstrated inhibitory activity on translation in the rabbit reticulocyte lysate system (IC50 = 8.0 µM) but did not affect proliferation of splenocytes. The activity of HIV‐1 reverse transcriptase was inhibited in the presence of angularin. Its N‐terminal sequence was GEPGQKE. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.