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31.
Thomas Soin Luc Swevers Georgia Kotzia Kostas Iatrou Colin R Janssen Pierre Rougé Toshiyuki Harada Yoshiaki Nakagawa Guy Smagghe 《Pest management science》2010,66(11):1215-1229
BACKGROUND: Diacylhydrazine (DAH) analogues have been developed successfully as a new group of insect growth regulators, called ecdysone agonists or moulting accelerating compounds. These DAHs have been shown to manifest their toxicity via interaction with the ecdysone receptor (EcR) in susceptible insects, as does the natural insect moulting hormone 20‐hydroxyecdysone (20E). A notable feature is their high activity and specificity, particularly against lepidopteran insects, raising the question as to whether non‐lepidopteran‐specific analogues can be isolated. However, for the discovery of ecdysone agonists that target other important insect groups such as Diptera, efficient screening systems that are based on the activation of the EcR are needed. RESULTS: In this study, a dipteran‐specific reporter‐based screening system with transfected S2 cells of Drosophila melanogaster Meig. was developed in order to discover and evaluate compounds that have ecdysone agonistic or antagonistic activity. A library of non‐steroidal ecdysone agonists containing different mother structures with DAH and other related analogues such as acylaminoketone (AAK) and tetrahydroquinoline (THQ) was tested. None of the compounds tested was as active as 20E. This is in contrast to the very high activity of several DAH and AAK congeners in lepidopteran cells (Bombyx mori L.‐derived Bm5 cells). The latter agrees with a successful docking of a DAH, tebufenozide, in the binding pocket of the lepidopteran EcR (B. mori), while this was not the case with the dipteran EcR (D. melanogaster). Of note was the identification of two THQ compounds with activity in S2 but not in Bm5 cells. Although marked differences in activity exist with respect to the activation of EcR between dipterans and lepidopterans, there exists a positive correlation (R = 0.724) between the pLC50 values in S2 and Bm5 cells. In addition, it was found through protein modelling that a second lobe was present in the ligand‐binding pocket of lepidopteran BmEcR but was lacking in the dipteran DmEcR protein, suggesting that this difference in structure of the binding pocket is a major factor for preferential activation of the lepidopteran over the dipteran receptors by DAH ligands. CONCLUSIONS: The present study confirmed the marked specificity of DAH and AAK analogues towards EcRs from lepidopteran insects. THQ compounds did not show this specificity, indicating that dipteran‐specific ecdysone‐agonist‐based insecticides based on the THQ mother structure can be developed. The differences in activity of ecdysone agonists in dipteran and lepidopteran ecdysone‐reporter‐based screening systems are discussed. Copyright © 2010 Society of Chemical Industry 相似文献
32.
Oocyte recruitment and fecundity type in fishes: Refining terms to reflect underlying processes and drivers 
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下载免费PDF全文 Only with new technology and the ability to simulate systems are we beginning to understand fish reproductive processes at the individual scale over time. Traditionally, oocyte recruitment and fecundity type in fishes have been based on a “snapshot” approach, that is a histological micrograph and/or oocyte size frequency distribution of a spawning capable female has been assumed to indicate oocyte recruitment processes over time. This has important implications as the asynchronous and group‐synchronous oocyte recruitment patterns are associated with indeterminate and determinate fecundity types, respectively, and thus affect estimates of reproductive potential and spawning biomass (if using egg production methods). However, a historic review of these terms revealed that they are not applied consistently, with the same oocyte recruitment pattern often assigned to both of these by different scientists. The intent of this study is to develop a conceptual model of oocyte recruitment processes over time, key drivers, and resulting “snapshots” to refine oocyte recruitment terms, definitions, and the methods needed to identify them. 相似文献
33.
Sweet sorghum (Sorghum bicolor (L.) Moench) was introduced recently into Greece and is being cultivated experimentally for the production of liquid biofuel.
A pilot survey was conducted in October 2005 to provide information on the species composition and density of its lepidopterous
stem borers, which appear to cause severe losses in production. The dominant pest in that season wasSesamia nonagrioides Lefebvre, with a mean density of 1.41 larvae per plant. Larvae were sampled from various plant internodes and found to have
a preference for the lower ones. Analysis of variance showed no significant effects on larval density of the irrigation levels
or of the organic — conventional soil fertilization method. A significant negative correlation was found between the body
length ofS. nonagrioides larvae and the internode from which they were retrieved. This is the first published report of sorghum borer pests in Greece.
http://www.phytoparasitica.org posting Feb. 7, 2007. 相似文献
34.
Stefanos Hatzilazarou Stefanos Kostas Athanasios S. Economou 《The Journal of Horticultural Science and Biotechnology》2019,94(4):441-447
In this study, an efficient protocol for the regeneration of encapsulated explants of oleander (Nerium oleander L.) has been developed. Shoot tips and 1st nodal segments below the shoot tip, from in vitro-derived oleander microshoots, were encapsulated in 2.5% sodium alginate prepared in liquid MS sucrose-free nutrient medium and hardened in 50 mM of calcium chloride producing solid beads, uniform in shape. These artificial seeds, irrespective of their maintenance under light or in darkness, germinated at frequencies of 38.8–42.2%, producing 3.0–3.3 microshoots per bead. In the case of using 100 mM of calcium chloride for hardening, the beads were firm, of uniform globular shape and suitable for handling, exhibiting a germination response of 68.9%. Encapsulated shoot tip explants, following storage at 4°C for 8 weeks, exhibited a higher regeneration response (60.0%) than non-encapsulated similar explants stored under the same conditions (11.1%). Microshoots, excised from cold-stored encapsulated explants after germination, rooted easily in agar-solidified MS medium with 2 μΜ IBA and after their transplantation into a peat-perlite substrate (3:1, v/v), were acclimatised successfully and established in the greenhouse with minimal losses. The present encapsulation procedure could be applied as an alternative method of micropropagation of desirable elite clones of oleander. 相似文献
35.
Akmoutsou P Mademtzoglou D Nakou I Onoufriadis A Papadopoulou X Kounatidis I Frantzios G Papadakis G Vasiliadis K Papadopoulos NT Mavragani-Tsipidou P 《Pest management science》2011,67(12):1534-1540
BACKGROUND: The insecticides spinosad and deltamethrin are being increasingly used in pest management programmes. In order to assess further their toxic effects to target and non‐target insect species, an evaluation was made of their insecticidal profile on Bactrocera oleae (Rossi) and Drosophila melanogaster (Meig.). Moreover, possible genotoxic effects of the two pesticides were investigated using the somatic mutation and recombination test (SMART) in D. melanogaster. RESULTS: Both insecticides were highly effective against B. oleae, exhibiting similar LC50 values. Moreover, they were found to be more effective against Bactrocera than against Drosophila adults. However, spinosad was significantly more toxic than deltamethrin to D. melanogaster. The results showed a lack of genotoxic activity of both insecticides under the in vivo experimental procedure employed, at least at applied doses. CONCLUSION: The present study provides information for lethal and sublethal effects of spinosad and deltamethrin against a target and a non‐target species. Both insecticides can exert high toxicity to B. oleae when adults are exposed even to very low doses for long periods of time. The results contribute to the database on the genotoxic potential of spinosad and deltamethrin, suggesting a safety profile for both insecticides. Copyright © 2011 Society of Chemical Industry 相似文献
36.
Seasonal changes in otolith increment width trajectories and the effect of temperature on the daily growth rate of young sardines 下载免费PDF全文
下载免费PDF全文 Eudoxia Schismenou Miquel Palmer Marianna Giannoulaki Itziar Alvarez Kostas Tsiaras George Triantafyllou Stylianos Somarakis 《Fisheries Oceanography》2016,25(4):362-372
We studied the otolith microstructure and growth of sardine, Sardina pilchardus, in the North Aegean Sea (eastern Mediterranean Sea), using samples of larvae and juveniles that had hatched in winter (November–January) and winter–spring (February–May), respectively. The juveniles had developed during an extended period coinciding with marked pelagic ecosystem changes (from winter, mixed conditions to summer, stratified waters). To examine the relationship between environmental changes and the observed variability in their otolith increment–width trajectories (width‐at‐age), we summarized the shape of trajectories with a four‐parameter set estimated from a growth model fit to each width trajectory. The individual parameter sets were then related to the potential oceanographic conditions that fish experienced during their development, derived from a hydrodynamic–biogeochemical model (POM‐ERSEM), implemented in the sampling area. Substantial seasonal effects were demonstrated on the otolith microstructure (platykurtic versus leptokurtic trajectories in winter‐mixed versus summer‐stratified conditions), which were related to the progressive sea surface warming. In a subsequent step, in order to study the effect of oceanographic conditions on larval and juvenile daily growth rates, a GAM (Generalized Additive Model) analysis of otolith increment widths was carried out, using model‐derived oceanographic parameters and taking into account the ‘inherent otolith growth’, expressed by the explanatory variables ‘previous increment width’ and ‘Age’. Results showed a strong and positive, linear effect of temperature on the growth rate of winter‐caught larvae, whereas in juveniles, which had developed within a wide range of temperatures, an optimum temperature for growth was observed at around 24°C. 相似文献
37.
Kostas Kalabokidis Gavriil Xanthopoulos Peter Moore David Caballero George Kallos Juan Llorens Olga Roussou Christos Vasilakos 《European Journal of Forest Research》2012,131(3):597-608
This paper describes the development of a decision support system (DSS) for prevention planning and emergency management of
forest fire events that incorporates weather data management, a geographical data viewer, a priori danger forecasting and
fire propagation modeling, automatic fire detection, and optimal resource dispatching. Collection, input, storage, management,
and analysis of the information rely on advanced and automated methodologies using remote sensing, GPS, digital mapping, and
geographic information systems. The results included short-term dynamic fire danger indices developed for improved and realistic
prevention and pre-suppression planning. An automatic fire detection technology based on infrared video was developed and
successfully tested on site. Several models for understanding fire propagation on forest fires have been proposed for practical
application. Additionally, a DSS was developed with the innovation of covering wildland fire hazard management entirely, providing
a complete coverage of technical and administrative activities that support decision makers in real time. The DSS was tested
for high fire seasons in two different sites in South Europe. 相似文献
38.
The Eurasian black vulture (Aegypius monachus) is a globally endangered species, vulnerable in Europe and endangered in Greece. We modelled its nesting preferences in Dadia reserve, northeastern Greece using logistic models at multi-scale level combined by Bayesian statistics. Compared with the random sites, the vultures nested at trees with greater diameter (DBH), lower height, and lower total number of trees around the nest tree, steeper slopes and greater distance from forest roads. Our results indicate that conservation and management guidelines for black vultures must aim: (1) to preserve old, isolated mature trees in the reserve, (2) to maintain the zones of strict protection as vulture sanctuary, including most of the suitable nesting habitat, (3) to protect the apparently suitable but still unused habitat in the rest of the reserve from disturbance and logging, (4) to monitor any changes in habitats and use our models to evaluate and predict their effect on vulture nesting in the reserve. 相似文献
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40.
Goodfellow M Papasouliotis K Cue S Crawford E Hall E 《Research in veterinary science》2008,84(3):490-493
Microcytosis is a common laboratory finding in dogs with iron deficiency and congenital portosystemic vascular anomalies (PSVA), however artefactual changes due to blood storage may occur which could mask this feature. This study evaluated the effects of storage on microcytosis in dogs with congenital PSVA. Full haematological parameters were measured on the day of sampling and following 24h storage at room temperature, in unaffected dogs (n=13) and in dogs affected with PSVA (n=24). Storage for 24h resulted in significantly higher MCV values in both groups of dogs (P<0.01). The percentage increase in MCV was greater in the control dogs (median 8.07%, range 5.64-9.31%) compared to affected dogs (median 6.05%, range 3.12-15.21%) (P<0.02). Storage of 1ml EDTA blood samples at ambient temperature for 24h prior to analysis, as occurs when samples are posted to external laboratories, will have significant effects on MCV and may mask microcytosis in dogs with PSVA. 相似文献