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Panagiotis J. Skouras George J. Stathas Costas Ch. Voudouris Anastasios I. Darras John A. Tsitsipis John T. Margaritopoulos 《Phytoparasitica》2017,45(2):165-173
Coccinella septempunctata L. is one of the most abundant ladybird species in Greece, preying on several aphid species and other arthropods, of which many are pests of cultivated plants. These pests are usually controlled with chemical insecticides. During this process, however, beneficials are also exposed to pesticides. The development of Integrated Pest Management (IPM) programs against aphids requires the evaluation of the effects of insecticides on beneficial insects. We evaluated the LD50 of imidacloprid, acetamiprid, bifenthrin and deltamethrin on first, second, third and fourth instar larvae of C. septempunctata by topical application. Moreover, we studied their sublethal effects (LD10) on the development, weight and prey consumption of fourth instar larvae. The topical application bioassays showed that deltamethrin and bifenthrin were highly toxic to all larval instars, whereas imidacloprid and acetamiprid were less toxic to fourth instar larvae. The LD10 dose significantly affected, developmental time, adult weight and daily predation. These results show the importance of assessing potential effect of insecticides on C. septempunctata for developing effective IPM programs of aphids in Greece. 相似文献
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Costas E. Stathopoulos Amalia A. Tsiami Bodgan J. Dobraszczyk J. David Schofield 《Journal of Cereal Science》2006,43(3):322-330
Flours from wheat varieties of differing bread-making quality were fractionated using a sequential salt precipitation technique. The gluten fractions in the different varieties varied in the proportion of HMW, LMW glutenins and gliadins. Their rheological behaviour was examined using constant strain (2%) small deformation oscillation tests over frequencies ranging from 0.005 to 10 Hz, before and after heating at 90 °C. The fractions containing a higher proportion of HMW glutenins were associated with a predominantly elastic character, whereas fractions containing mostly gliadins exhibited a viscous-like behaviour. The frequency dependent rheological behaviour of fractions containing HMW proteins was less susceptible to heat, and their elastic character was maintained after heating, whereas the rheology of intermediate fractions and fractions containing mostly gliadins was more susceptible to heating, indicating a rapid change from viscous to elastic behaviour after heating. 相似文献
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Costas E. Stathopoulos Amalia A. Tsiami J. David Schofield Bogdan J. Dobraszczyk 《Journal of Cereal Science》2008
Gluten was extracted from flours of several different wheat varieties of varying baking quality. Creep compliance was measured at room temperature and tan δ was measured over a range of temperatures from 25 to 95 °C. The extracted glutens were heat-treated for 20 min at 25, 40, 50, 60, 70 and 90 °C in a water bath, freeze-dried and ground to a fine powder. Tests were carried out for extractability in sodium dodecyl sulphate, free sulphydryl (SH) groups using Ellman's method, surface hydrophobicity and molecular weight (MW) distribution (MWD) using field-flow fractionation and multi-angle laser light scattering. With increasing temperature, the glutens showed a decrease in extractability, with the most rapid decreases occurring between 70 and 90 °C, a major transition in tan δ at around 60 °C and a minor transition at 40 °C for most varieties, a decrease in free SH groups and surface hydrophobicity and a shift in the MWD towards higher MW. The poor bread-making variety Riband showed the highest values of tan δ and Newtonian compliance, the lowest content of free SH groups and the largest increase of HMW/LMW with increasing temperature. No significant correlations with baking volume were found between any of the measured parameters. 相似文献
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Functional and structural characteristics of corticular photosynthesis of sun-exposed bark of olive tree (Olea europaea L.) were examined. Stomata are only sporadically present during stem primary growth. Light transmission through the phellem was age dependent, decreasing rapidly in stems older than five years of age. Light transmission was also low in pubescent 1-year-old stems. Light transmission was about 50% higher in wet phellem than in dry phellem. Photosynthetic capacity on a unit area basis (measured with an oxygen disc electrode at 27 degrees C and about 5% CO(2) on chlorophyllous tissue discs isolated from the stem) was higher in 1-, 20- and 30-year-old stems compared with 2-10-year-old stems. Low chlorophyll a/b ratio and light compensation points were recorded in olive stems with low phellem light transmission, in accordance with the shade acclimation hypothesis. The intrinsic photochemical efficiency of photosystem II of all stems, especially young stems, was less than that of the leaves. Our results show that olive tree bark possesses an efficient photosynthetic mechanism that may significantly contribute not only to the reduction in concentrations of CO(2) in the inner bark, but also to whole-tree carbon balance. 相似文献
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Rui A. Gonalves Renata Serradeiro Marina Machado Benjamin Costas Christine Hunger Jorge Dias 《Journal of the World Aquaculture Society》2019,50(6):1078-1092
The inclusion of phytogenics in fish feed is a promising strategy to compensate for the negative performance effects of replacing fishmeal (FM) with vegetable sources. The present work assessed the interactive effects of different dietary FM levels (22.5 and 10% of formulation) and the supplementation of a commercial blend of anise, citrus, and oregano essential oils (Digestarom PEP M.G.E 150) on European sea bass, Dicentrarchus labrax growth performance, nutrient utilization, gut morphology, antioxidant status, and immunological response over a 60‐day growth trial. Results showed decreased growth and protein efficiency ratio and increased feed conversion ratio with a low dietary FM level. In contrast, supplementation of the phytogenic product demonstrated improved performance and nutrient utilization together with increased protein and energy retention. Supplementation with the plant essential oils fully compensated for the negative intestinal changes observed in sea bass fed a low‐FM diet but showed little improvement in fish immunological response, except for the 30% increase in lysozyme activity observed in fish fed the low FM‐supplemented diet compared to those fed the standard high‐FM diet. Overall, this study supports the use of this phytogenic product in low‐FM diets as a possible tool to decrease feed costs associated with FM without compromising fish performance, nutrient utilization, and health. 相似文献
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Under the view of species genetic erosion and the need of better crops, wild species could become important germplasm sources
for breeding. At present, several wild Avena species are used as donors of valuable characters in oat breeding. In this study, wild oat distribution and diversity in
wheat, barley and oat fields of Greece was examined by means of a 3-year survey in some typical cereal producing regions in
the central part of the country. Greenhouse experiments were also conducted in order to compare seedlings grown from wild
oat accessions of these regions under the same conditions. A total of 151 fields were surveyed and 158 accessions of wild
oats were studied in terms of some morphological traits. The occurrence and distribution of A. sterilis was very high, while a noticeable and first-time analytically reported presence of A. fatua was evident in some of the surveyed wheat fields. The high diversity of wild oat was furthermore indicated by means of the
pot experiments. The high degree of phenotypic variation in A. sterilis could be attributed to the earlier introduction of this species in the sampling area, compared to A. fatua. Wild oat distribution and diversity in a region seems crucial for the cereal production and is an important parameter which
must be considered in evaluating efficacy of weed control strategies, while genes controlling these characters could be potentially
used to improve cultivated forms of oats or other cereals. 相似文献
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Benjamín Costas Cláudia Aragão Juan Miguel Mancera Maria Teresa Dinis & Luís E C Conceição 《Aquaculture Research》2008,39(1):1-9
Fish held at high stocking densities are generally exposed to chronic stress situations that impose severe energy demands and may predispose the fish to infection. Senegalese sole Solea senegalensis (Kaup) juveniles (78.8±18.9 g body weight) were maintained at low (LSD; 4 kg m?2 at the end of the experiment), medium (MSD; 9 kg m?2) and high (HSD; 14 kg m?2) stocking densities during a period of 63 days. Although disease outbreaks were observed in fish reared at HSD, growth and food consumption did not vary among different treatments. Results from plasma cortisol and free amino acids (FAAs) showed significant differences among different rearing densities pointing to HSD as stressful rearing condition. However, higher plasma glucose and osmolality levels indicated that fish held at MSD may also be under stress. The higher usage of FAAs from the HSD group may be due to the higher demand for energy production in order to cope with stressful rearing conditions, higher rate of protein synthesis or due to synthesis of other important metabolites related to stress response. Therefore, results from the present study point out to HSD as a stressful rearing condition and suggest that crowding stress may affect amino acid requirements. 相似文献
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The distribution of ventilation-perfusion (VA/Q) ratios, before and after 100 per cent oxygen, was studied in an induced-premature foal at 4 h and again at eleven days of age, using the multiple inert gas elimination technique. The major finding was an absence of low VA/Q ratios when breathing air, indicating that low PaO2 in the neonatal period was totally attributable to the right-to-left shunt. At 4 h of age the PaO2 was 5.48 kPa and the right-to-left shunt represented 33.4 per cent of the cardiac output. At eleven days of age the PaO2 was 9.76 kPa and right-to-left shunt was 10.1 per cent of cardiac output. At both ages there was a separate high mode where ventilation was greatly in excess of blood flow but at neither age were units with low VA/Q ratios present. Oxygen breathing for 40 mins did not increase the right-to-left shunt, but at eleven days right-to-left shunt decreased when 100 per cent oxygen was administered. 相似文献
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