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1.
Mutants of Ustilago maydis (DC) Corda with high resistance to azoxystrobin (RF 164 to 4714, based on EC50 values), an inhibitor of mitochondrial electron transport at the cytochrome bc1 complex, were isolated in a mutation frequency of 2.3 x 10(-7) after nitrosoguanidine mutagenesis and selection on media containing 1 microgram ml-1 azoxystrobin in addition to 0.5 mM salicylhydroxamate (SHAM), a specific inhibitor of cyanide-resistant (alternative) respiration. Oxygen uptake in whole cells was strongly inhibited in the wild-type strains by azoxystrobin (1.5 micrograms ml-1) in addition to SHAM (1 mM), but not in the mutant isolates. Genetic analysis with nine such mutant isolates resulted in progeny phenotypes which did not follow Mendelian segregation, but satisfied the criteria of non-Mendelian (cytoplasmic) heredity. In crosses between three mutant isolates with the compatible wild-type strains, the sensitivity was inherited by progeny maternally from the wild-type parent strain (criterion of uniparental inheritance). In crosses between wild-type strains and remaining mutant isolates, a continuous distribution of sensitivity in the progeny was found (criterion of vegetative segregation). The third criterion of cytoplasmic resistance (criterion of intracellular selection) was fulfilled by experiments on the stability of resistance phenotypes. With two exceptions, a reduction of resistance was observed in the mutant strains when they were grown on inhibitor-free medium. Recovery of the high resistance level was observed after they were returned to the selection medium. Cross-resistance studies with other fungicides, which also inhibit electron transport through complex III of respiratory chain, showed that mutations for resistance to azoxystrobin were also responsible for reduced sensitivity to kresoxim-methyl (RF 18 to 1199) and to antimycin-A (RF 20 to 305), which act at the Qo and Qi sites of the cytochrome bc1 complex, respectively. Studies of the fitness of azoxystrobin-resistant isolates showed that these mutations appeared to be pleiotropic, having significant adverse effects on growth in liquid culture and pathogenicity on young corn plants. 相似文献
2.
Vassiliki Kati Marc Dufrêne Anastasios Legakis Philippe Lebrun 《Biological conservation》2004,115(1):33-44
The diversity patterns, the ecological structure and the typical species of the orthopteran assemblage in the Dadia reserve are investigated. The reserve was designed to protect the black vulture (Aegypius monachus) and other raptors. A total of 39 orthopteran species were found, including Paranocarodes chopardi, a pamphagid species with very restricted distribution. All species can be represented in a network of six complementary habitats, including open oak woodlands, agricultural fields separated with hedges, humid grasslands, as well as serpentine grasslands. The buffer zone of the reserve is far more important for Orthoptera conservation than the core areas, which host most of the black vulture nests. Management focusing on raptors is in general compatible with conservation of Orthoptera. We suggest the maintenance of forest openings in the buffer zone, the maintenance of forest heterogeneity, the enhancement of periodical livestock grazing, and the use of nine indicator species and Paranocarodes chopardi in the reserve monitoring program. 相似文献
3.
Phosphorus adsorption isotherms are presented for samples from agricultural areas in central Greece. The soils contain montmorillonitic clays, have high exchange capacities and range in pH from 6.8 to 8.1. The amounts of P adsorption are high for surface and subsurface samples and are comparable to the adsorption observed in acid kaolinitic soils. The fit of the Freundlich equation to the experimental data was significantly improved when NaHCO3 extractable P was used as an estimate of the labile soil P to account for P already adsorbed in the soil. No conclusive relationship was established between the Freundlich parameters and selected soil properties though in some cases a values (capacity term) increased with increasing organic carbon content. 相似文献
4.
Anastasios I. Darras Vasilios DemopoulosChrysovalanti Tiniakou 《Postharvest Biology and Technology》2012,64(1):168-174
UV-C (λ = 254 nm) irradiation was effective in reducing Botrytis cinerea floret specking (i.e., lesion development) and maintaining a better postharvest quality of cut gerbera flowers. A range of UV-C doses (0.5-10.0 kJ m−2) was tested on ‘Ice cream’ and ‘Ecco’ gerbera flowers to activate germicidal and inducible defence mechanisms. Irradiation of B. cinerea cultures with 0.5, 1.0, 2.5 and 5.0 kJ m−2 UV-C resulted in up to a 10-fold reduction of conidial germination percentages and significant (P < 0.05) delay of mycelium growth, compared to the non-irradiated control cultures. Moreover, lesion diameters on gerbera florets inoculated with UV-C irradiated B. cinerea cultures were reduced by up to 70%, suggesting that UV-C had a negative effect on the pathogenic strength of the fungi. Lesion diameters on florets of UV-C irradiated gerberas were reduced by up to 55% giving evidence that defence responses in the host tissue were induced. Concentration of total phenolics seemed to be unaffected by 0.5 kJ m−2 UV-C treatment in both cultivars, but polyphenol oxidase (PPO) activity increased and remained higher compared to the non-irradiated control flowers throughout the 48 h storage period at 20 °C. The increase of PPO suggests that this enzyme might play an important role in host defence mechanisms that suppressed B. cinerea floret specking. Gerbera flowers irradiated with 1.0 or 10.0 kJ m−2 UV-C showed improvement in vase-life by 1.8 and 2.4 d, decrease in stem break percentages by 43 and 29% and delay in stem break incidence by 3.3 and 1.3 d, respectively. 相似文献
5.
Molecular typing of Brucella melitensis endemic strains and differentiation from the vaccine strain Rev-1 总被引：1，自引：0，他引：1
Noutsios GT Papi RM Ekateriniadou LV Minas A Kyriakidis DA 《Veterinary research communications》2012,36(1):7-20
In the present study forty-four Greek endemic strains of Br. melitensis and three reference strains were genotyped by Multi locus Variable Number Tandem Repeat (ML-VNTR) analysis based on an eight-base
pair tandem repeat sequence that was revealed in eight loci of Br. melitensis genome. The forty-four strains were discriminated from the vaccine strain Rev-1 by Restriction Fragment Length Polymorphism
(RFLP) and Denaturant Gradient Gel Electrophoresis (DGGE). The ML-VNTR analysis revealed that endemic, reference and vaccine
strains are genetically closely related, while most of the loci tested (1, 2, 4, 5 and 7) are highly polymorphic with Hunter-Gaston
Genetic Diversity Index (HGDI) values in the range of 0.939 to 0.775. Analysis of ML-VNTRs loci stability through in vitro
passages proved that loci 1 and 5 are non stable. Therefore, vaccine strain can be discriminated from endemic strains by allele’s
clusters of loci 2, 4, 6 and 7. RFLP and DGGE were also employed to analyse omp2 gene and reveled different patterns among Rev-1 and endemic strains. In RFLP, Rev-1 revealed three fragments (282, 238 and
44 bp), while endemic strains two fragments (238 and 44 bp). As for DGGE, the electrophoretic mobility of Rev-1 is different
from the endemic strains due to heterologous binding of DNA chains of omp2a and omp2b gene. Overall, our data show clearly that it is feasible to genotype endemic strains of Br. melitensis and differentiate them from vaccine strain Rev-1 with ML-VNTR, RFLP and DGGE techniques. These tools can be used for conventional
investigations in brucellosis outbreaks. 相似文献
6.
Georgios?Kountios Athanasios?RagkosEmail author Thomas?Bournaris Georgios?Papadavid Anastasios?Michailidis 《Precision Agriculture》2018,19(3):537-554
Precision agriculture (PA) constitutes a dynamic production method which is gaining attention in several parts of the world. Its environmental and economic sustainability has been examined in terms of its ability to reduce the adverse effects of agrochemical use—by regulating their application to the levels needed at the land parcel level—and of its contribution to higher incomes and profitability. At the social level, PA has been linked to collective action although little insight is available regarding the role of various actors and education. This study tackles PA through an assessment of the attitudes of farmers towards the elements of its sustainability and of their educational needs. The analysis of survey data of a sample of young farmers in Greece showed that the majority of respondents were not familiar with PA. Significant differences were found between the attitudes of knowledgeable and non-knowledgeable farmers, the former demonstrating better acknowledgement of the environmental, economic and social sustainability of PA. Important educational needs were also detected, with group and individual methods being the most preferred ones for education and information campaigns. The results of the analysis could be of use for the design of Common Agricultural Policy Pillar II measures for the promotion of PA targeting to specific audiences and actors. 相似文献
7.
The present study analyzes the structure and dynamics of the forest landscape in a peri-urban area(Rome, Italy) during the city's expansion from 1949 to2008 using landscape metrics and change detection analysis of digital maps of the area(1500 km2). While urban settlements increased continuously from 6.5 to 27.5 % of the study area, woodlands changed less clearly, with a moderate increase(from 11.2 to 11.9 % of the total area)and a higher fragmentation as a consequence of Rome's expansion. The structure of forest landscape changed along the urban-to-rural gradient with patch size increasing with the distance to the inner city in 1949 and substantial landscape homogeneity in 2008. The indicators proposed in this study inform dedicated measures for conserving forest and maintaining landscape diversity. Measures adopted in Rome's forestation plan to counteract woodlandffragmentation were analyzed and discussed. Based on the complex landscape dynamics found for Rome, an integrated multiscale planning approach targeting forest conservation is considered a key contribution to urban sustainability. 相似文献
8.
Leukocyte counts in bronchoalveolar lavage fluid obtained from normal and Maedi–Visna‐infected sheep
Panagiotis D. Katsoulos Georgios Christodoulopoulos Georgios Kontopidis Anastasios Minas Athanasia Tzivara Spyridon K. Kritas 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2009,38(3):397-402
Background: Bronchoalveolar lavage has proven helpful for the diagnosis of certain ovine diseases of the lungs. There is insufficient data concerning the leukocyte profile of bronchoalveolar lavage fluid (BALF) from MaediVisna infected sheep. Objective: The objective of this study was to assess the differential leukocyte profile of BALF associated with Maedi virus infection in sheep and to determine whether cytologic examination of BALF is an effective way to diagnose Maedi or determine the severity of lung lesions. Methods: BALF and serum samples were analyzed from 400 sheep. Sediment smears of bronchoalveolar lavage were stained with Diff‐Quik and examined microscopically to obtain a 200‐cell differential cell count. Serum was tested using a commercial kit for Maedi–Visna virus antibodies. Lung samples obtained at the time of slaughter were weighed and examined histologically. Results: Maedi‐infected sheep (n=267; seropositive with lung lesions) had a significantly higher percentage of lymphocytes and lower percentage of macrophages in BALF than normal sheep (n=133; seronegative and no lung lesions). These differences were significantly more severe in animals with advanced vs moderate lung lesions. Using classification trees, a cut‐off of 13.5% lymphocytes was predictive of Maedi infection and a cut‐off of 24.5% lymphocytes was predictive of advanced lung lesions. Conclusions: Cytologic examination of BALF is useful for the clinical diagnosis of Maedi in sheep and provides important information about the severity of the lung lesions. 相似文献
9.
Ioannis?GravalosEmail author Anastasios?Georgiadis Dimitrios?Kateris Theodoros?Gialamas Evagelos?Bompolas Zisis?Tsiropoulos Avgoustinos?Avgoustis Panagiotis?Xyradakis 《Precision Agriculture》2017,18(1):19-36
This research is a study on the relationship of irrigation water treatments and soil moisture distribution uniformity (DU). Soil moisture distribution was based on long-term data sets that were collected using a novel electromagnetic sensor-based platform moving inside sub-surface horizontal access-tubes. The research was conducted under controlled laboratory conditions in a soil tank. The irrigation treatments regarding two case studies under dry and wet soil conditions (from permanent wilting point to field capacity) were conducted for a period of 115 and 110 days respectively. In dry soil conditions, the irrigation water treatments strongly affect the DU of soil moisture that can be achieved constantly using non-uniform irrigation treatments. In contrast, the DU of soil moisture in wet soil conditions was maintained at a high percentage and was slightly affected by irrigation treatments. However, obtaining accurate soil moisture information at a large scale over a long period can be used to improve water use efficiency. 相似文献
10.
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