Quantity and transmission efficiency of an isolate of the Potato virus Y–Wilga (PVYN−Wi) by aphid species reared on different host plants     

Kamangar  Saman Bahrami  Taning  Clauvis Nji Tizi  De Jonghe  Kris  Smagghe  Guy 《植物病害和植物保护杂志》2019,126(6):529-534

Journal of Plant Diseases and Protection - Potato virus Y (PVY) is a destructive plant virus causing important damage in different crops, particularly in potato. PVY is transmitted in a...  相似文献   

Microbial N-dealkylation of atrazine: Effect of exogeneous organic substrates and behaviour of the soil microflora     

Abdellah Yassir  Catherine Rieu  Guy Soulas 《Pest management science》1998,54(1):75-82

It has been demonstrated that atrazine side-chain mineralisation could be substantially stimulated by addition of carbon-containing substrates such as cellulose, green manure, straw or sawdust in the presence of NH₄⁺ nitrogen but poorly affected by amendments with glucose. Cellulose has the most beneficial effect. For that substrate it has been shown that (i) simultaneous application of the organic amendment and atrazine results in kinetics for side-chain dealkylation showing a lag phase which is reduced or even eliminated by preliminary incubation with the amendment, (ii) rate and extent of mineralisation of the ethylamino side chain are significantly accelerated by decreasing the C/N ratio of the amendment. By comparison, mineralisation of the isopropylamino side chain is not appreciably affected by a change in the value of the C/N ratio as far as atrazine is applied within a two- to three-week period following the organic treatment after which a small deficit in N supply has a definite beneficial effect on mineralisation. Cellulose and, to a lesser extent, straw induce a biphasic change in bacterial number with more numerous and/or active atrazine degraders being predominantly found in the later-developing bacterial community. The fungal microflora is relatively unaffected by all types of carbon substrates but glucose and, unexpectedly, by atrazine at high ratio of application. Activation of atrazine mineralisation seems to be a co-metabolic process which is kinetically controlled by the rate of release from polymerised C substrates of easily available and readily metabolisable low-molecular-weight co-substrates. Transient production of glucose as an end-product of cellulose depolymerisation might induce catabolic repression of dealkylation enzyme systems and be responsible for a lag in atrazine side-chain mineralisation. © 1998 Society of Chemical Industry  相似文献   

Scale-dependent correlates of reptile communities in natural patches within a fragmented agroecosystem     

Rotem  Guy  Giladi  Itamar  Bouskila  Amos  Ziv  Yaron 《Landscape Ecology》2020,35(10):2339-2355

Landscape Ecology - Studying biodiversity in light of increased fragmentation in agroecosystems requires the understanding of scale-dependent and multi-scale determinants of various community...  相似文献   

Neospora caninum in persistently infected, pregnant cows: spontaneous transplacental infection is associated with an acute increase in maternal antibody.     

C S Guy  D F Williams DJLKelly  J W McGarry  F Guy  C Bj?rkman  R F Smith  A J Trees 《The Veterinary record》2001,149(15):443-449

Nine cows which were naturally and persistently infected with Neospora caninum were housed and observed intensively throughout pregnancy. No recrudescence of a latent infection was detected by PCR tests on maternal blood but fetal infection, implying a recrudescence of maternal parasitosis, was associated with a marked increase in maternal antibody. The increase occurred in the second half of pregnancy in five cows which infected their calves, and before mid-pregnancy in one cow which aborted. There was no change in the avidity of the antibody, which remained high and characteristic of long-term infection. In three infected cows that gave birth to uninfected calves there was no marked increase in maternal antibody. Antigen-specific interferon gamma responses of peripheral blood mononuclear cells were observed in all the infected cattle but they did not vary significantly either during pregnancy, or whether the cows did or did not infect their calves, although the responses were consistently higher in the latter. There was no change in the plasma concentrations of cortisol or acute phase proteins associated with the recrudescence of the parasite. Three uninfected cows housed with the infected cows remained uninfected throughout the experiment. No immunosuppressive event was detected which might have provoked parasite recrudescence but the acute antibody rise associated with transplacental infection provides a valuable, non-invasive marker for further studies to investigate the cause and consequences of parasite recrudescence in N caninum infection in cattle.  相似文献   

Uptake and residues of aldicarb in sugarbeet leaves     

Willy Dejonckheere  Guy Melkebeke  Walter Steurbaut  Rent H. Kips 《Pest management science》1982,13(4):341-350

The breakdown of aldicarb and its oxidation products (the sulphoxide and the sulphone, aldoxycarb), under field conditions in 1976, were studied on three different types of soil (a sandy loam, a silt loam and a sandy clay loam that were normally cropped with sugarbeet). Residues were determined in leaves, stems, roots and soil, and related to aphid counts. Higher doses were needed on heavy soils in order to obtain a sufficient concentration in the leaves and thus provide an efficient treatment for aphid control. Weather conditions, especially rainfall, also affected the residue content. At harvest, the sugar beet tops used for fodder can contain residues which vary widely, depending on dosage, soil type and climatic conditions.  相似文献   

Post-genomics of microsporidia, with emphasis on a model of minimal eukaryotic proteome: a review     

Texier C  Brosson D  El Alaoui H  Méténier G  Vivarès CP 《Folia parasitologica》2005,52(1-2):15-22

The genome sequence of the microsporidian parasite Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 contains about 2,000 genes that are representative of a non-redundant potential proteome composed of 1,909 protein chains. The purpose of this review is to relate some advances in the characterisation of this proteome through bioinformatics and experimental approaches. The reduced diversity of the set of E. cuniculi proteins is perceptible in all the compilations of predicted domains, orthologs, families and superfamilies, available in several public databases. The phyletic patterns of orthologs for seven eukaryotic organisms support an extensive gene loss in the fungal clade, with additional deletions in E. cuniculi. Most microsporidial orthologs are the smallest ones among eukaryotes, justifying an interest in the use of these compacted proteins to better discriminate between essential and non-essential regions. The three components of the E. cuniculi mRNA capping apparatus have been especially well characterized and the three-dimensional structure of the cap methyltransferase has been elucidated following the crystallisation of the microsporidial enzyme Ecm1. So far, our mass spectrometry-based analyses of the E. cuniculi spore proteome has led to the identification of about 170 proteins, one-quarter of these having no clearly predicted function. Immunocytochemical studies are in progress to determine the subcellular localisation of microsporidia-specific proteins. Post-translational modifications such as phosphorylation and glycosylation are expected to be soon explored.  相似文献   

Quantitative structure-activity studies of insect growth regulators: XVIII. Effects of substituents on the aromatic moiety of dibenzoylhydrazines on larvicidal activity against the Colorado potato beetle Leptinotarsa decemlineata     

Nakagawa Y  Smagghe G  Van Paemel M  Tirry L  Fujita T 《Pest management science》2001,57(9):858-865

Larvicidal activity against the Colorado potato beetle Leptinotarsa decemlineata (Say) was measured for a series of N-tert-butyl-dibenzoylhydrazines having various substituents on the benzoyl (A-ring) moiety nearer to the tert-butyl group, with the other benzoyl (B-ring) moiety being unsubstituted. The effects of these substituent on the larvicidal activity were analyzed using classical quantitative structure-activity relationship (QSAR) procedures. The effects of substituents on the A-ring moiety on larvicidal activity were entirely different from those against the lepidopteran rice stem borer Chilo suppressalis (Walker) previously reported. Position-specific steric and hydrophobic effects, as well as certain substitution patterns, were likely to participate in modifying the larvicidal activity. The activity of para-substituted compounds was generally lower than that of un-, ortho- and meta-substituted compounds. Most multi-substituted compounds showed an activity equivalent to or lower than that of the unsubstituted compound. Among 46 compounds tested, the 2-sec-butoxy analogue was most potent against L decemlineata, although this compound had previously been shown to be only weakly active against C suppressalis.  相似文献   

Enhancement of fungicidal and insecticidal activity by reductive alkylation of chitosan     

Rabea EI  El Badawy M  Rogge TM  Stevens CV  Steurbaut W  Höfte M  Smagghe G 《Pest management science》2006,62(9):890-897

A series of N-alkyl chitosan (NAC) derivatives were synthesized using a reductive alkylation reaction to examine their fungicidal and insecticidal activity. The chemical structures were characterized by IR and (1)H NMR spectroscopy, and the degree of substitution (DS) ranged from 0.02 to 0.37. Their fungicidal activity was evaluated against the grey mould Botrytis cinerea Pers ex Fr (Leotiales: Sclerotiniaceae) and the rice leaf blast pathogen Pyricularia grisea Sacc [Teleomorph: Magnaporthe grisea (Hebert) Barr] by a radial growth bioassay. It was of interest that most of the NAC derivatives were more active against both fungi than chitosan itself. The most active derivative was N-(2,2-diphenylethyl)chitosan with EC50 values of 0.031 and 0.23 g L(-1) against B. cinerea and P. grisea respectively. In addition, some derivatives, at higher concentrations up to 1.0 g L(-1), inhibited the mycelial growth and spore formation of P. grisea. Bioassays against larvae of the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) with the NAC derivatives at a rate of 5.0 g kg(-1) in artificial diet demonstrated that N-(3-phenylbutyl)chitosan was the most active compound. In addition, N-propylchitosan, N-undecanylchitosan and N-(3-phenylpropyl)chitosan derivatives strongly inhibited larval weight gain in S. littoralis, with respective reductions of 76, 66 and 65% after 4 days of feeding on treated diet.  相似文献   

Exposure to chronic moderate hypoxia impacts physiological and developmental traits of European sea bass (Dicentrarchus labrax) larvae     

Gwenaëlle Vanderplancke  Guy Claireaux  Patrick Quazuguel  Christine Huelvan  Charlotte Corporeau  David Mazurais  José-Luis Zambonino-Infante 《Fish physiology and biochemistry》2015,41(1):233-242

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Transurethral cystoscopy in dogs with recurrent urinary tract infections: Retrospective study (2011-2018)     

Marie Llido  Catherine Vachon  Melanie Dickinson  Guy Beauchamp  Marilyn Dunn 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(2):790-796

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