Formation of chlamydospores and microsclerotia in Alternaria dauci     

Anastasia L. Lagopodi  Georgios T. Tziros 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(3):311-316

Alternaria dauci (Kühn) Groves and Skolko, the cause of leaf blight of carrot, was observed to produce chlamydospores and microsclerotia in vitro. Four different isolates produced chlamydospores on potato dextrose agar, V8 agar and Czapek-Dox agar at 10, 18 and 28°C, from neighbouring cells of hyphae of the submerged mycelium, forming long chains. Formation of chlamydospores was completed in a multiple stage process, including swelling of cells, development of secondary septa, rounding up of cells and cell wall thickening. Mature chlamydospores were released from the mycelium mostly in clusters and in short or long chains, and sometimes in pairs. They were globose to ellipsoid, smooth or verrucose, pale brown in colour, and averaged 13.87?×?11.37 μm, (length × width). Microsclerotia were formed on PDA, by only one isolate, at 28°C first at the edges of the colony, by close contact of hyphae that exhibited extensive branching and intermingling. In their final form microsclerotia were multi-celled, closely attached masses of short and broad dark grey cells, less compact woven at the edges of the microsclerotium. This is the first illustration of chlamydospore and microsclerotia formation in Alternaria dauci.  相似文献   

Acetylcholinesterase point mutations in European strains of Tetranychus urticae (Acari: Tetranychidae) resistant to organophosphates     

Jahangir Khajehali  Thomas Van Leeuwen  Maria Grispou  Evangelia Morou  Haoués Alout  Mylène Weill  Luc Tirry  John Vontas  Anastasia Tsagkarakou 《Pest management science》2010,66(2):220-228

BACKROUND: In Tetranychus urticae Koch, acetylcholinesterase insensitivity is often involved in organophosphate (OP) and carbamate (CARB) resistance. By combining toxicological, biochemical and molecular data from three reference laboratory and three OP selected strains (OP strains), the AChE1 mutations associated with resistance in T. urticae were characterised. RESULTS: The resistance ratios of the OP strains varied from 9 to 43 for pirimiphos‐methyl, from 78 to 586 for chlorpyrifos, from 8 to 333 for methomyl and from 137 to 4164 for dimethoate. The insecticide concentration needed to inhibit 50% of the AChE1 activity was, in the OP strains, at least 2.7, 55, 58 and 31 times higher for the OP pirimiphos‐methyl, chlorpyrifos oxon, paraoxon and omethoate respectively, and 87 times higher for the CARB carbaryl. By comparing the AChE1 sequence, four amino acid substitutions were detected in the OP strains: (1) F331W (Torpedo numbering) in all the three OP strains; (2) T280A found in the three OP strains but not in all clones; (3) G328A, found in two OP strains; (4) A201S found in only one OP strain. CONCLUSIONS: Four AChE1 mutations were found in resistant strains of T. urticae, and three of them, F331W, G328A and A201S, are possibly involved in resistance to OP and CARB insecticides. Among them, F331W is probably the most important and the most common in T. urticae. It can be easily detected by the diagnostic PCR‐RLFP assay developed in this study. Copyright © 2009 Society of Chemical Industry  相似文献   

SPORE series winner. Science 101: building the foundations for real understanding     

Thanukos A  Scotchmoor JG  Caldwell R  Lindberg DR 《Science (New York, N.Y.)》2010,330(6012):1764-1765

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Farmers’ attitudes and landscape change: evidence from the abandonment of terraced cultivations on Lesvos,Greece     

Thanasis Kizos  Anastasia Dalaka  Theodora Petanidou 《Agriculture and Human Values》2010,27(2):199-212

Agricultural landscapes are the product of the interaction of the natural environment of an area and the practices of its farmers. In this paper, farmers’ practices are examined in order to describe and understand processes of landscape change in terraced fields on the island of Lesvos, Greece. We examine the changes of the terraced fields of each farmer and the reasons for these changes, practices concerning the maintenance of terraces and how farmers view this landscape change. The concept of farming systems is used to link farmers’ practices at the farm level with changes at the landscape level. Data come from research via questionnaires to farmers in order to record their practices, to explore changes in land use and the landscape elements and the reasons behind these changes, and finally to record their opinions on the landscape change that result. Findings indicate that although farm households in the case study areas depend on farming incomes by very different degrees, they employ similar cultivation and landscape management practices. At the same time, “hobby” farm households may be more prone to abandonment of fields and negligence of landscape elements (here terraces).  相似文献   

Nature-inspired soluble iron-rich humic compounds: new look at the structure and properties     

Tatiana A. Sorkina  Alexander Yu. Polyakov  Natalia A. Kulikova  Anastasia E. Goldt  Olga I. Philippova  Alina A. Aseeva  Alexey A. Veligzhanin  Yan V. Zubavichus  Denis A. Pankratov  Eugene A. Goodilin  Irina V. Perminova 《Journal of Soils and Sediments》2014,14(2):261-268

Purpose

Humic substances (HS) being natural polyelectrolyte macromolecules with complex and disordered molecular structures are a key component of the terrestrial ecosystem. They have remarkable influence on environmental behavior of iron, the essential nutrient for plants. They might be considered as environmental friendly iron deficiency correctors free of synthetic iron (III) chelates disadvantages. The main goal of this study was to obtain water-soluble iron-rich humic compounds (IRHCs) and to evaluate their efficiency as chlorosis correctors.

Materials and methods

A facile preparation technique of IRHCs based on low-cost and available parent material was developed. The iron-containing precursor (ferrous sulfate) was added dropwisely into alkaline potassium humate solution under vigorous stirring and pH-control. A detailed characterization both of organic and inorganic parts of the compounds was provided, the iron species identification was carried out jointly by EXAFS and Mössbauer spectroscopy. Bioassay experiments were performed using cucumber Cucumis sativus L. as target plants. Plants were grown in modified Hoagland nutrient solution, prepared on deionized water and containing iron in the form of IRHCs. Total iron content in dry plants measured by spectrophotometry after oxidative digestion and the chlorophyll a content determined after acetone extraction from fresh plant were used as parameters illustrating plants functional status under iron deficiency condition.

Results and discussion

The high solubility (up to130 g/l) and iron content (about 11 wt%) of the IRHCs obtained allow considering them to be perspective for practical applications. A set of analytical methods has shown that the main iron species in IRHCs are finely dispersed iron (III) oxide and hydroxide nanoparticles. An application of the precursor solution acidification allows to obtain compounds containing a significant part of total iron (up to 30 %) in the form of partly disordered iron (II–III) hydroxysulphate green rust GR(SO₄ ^2?). Bioavailability of iron from IRHCs was demonstrated using bioassay in cucumber plants grown up on hydroponics under iron deficiency conditions.

Conclusions

The application of iron oxides chemistry for humic substance containing solution was proved to be an effective approach to synthesis of IRHCs. Using bioassay on cucumber plants C. sativus L. under iron deficiency conditions, the efficiency of compounds obtained as chlorosis correctors was demonstrated. Application of water-soluble IRHCs led to significant increase of chlorophyll a content (up to 415 % of the blank) and iron content in plants (up to 364 % of the blank) grown up on hydroponics.  相似文献   

Current status of insecticide resistance in Q biotype Bemisia tabaci populations from Crete     

Emmanouil Roditakis  Maria Grispou  Evangelia Morou  Jon Bent Kristoffersen  Nikos Roditakis  Ralf Nauen  John Vontas  Anastasia Tsagkarakou 《Pest management science》2009,65(3):313-322

BACKGROUND: A major problem of crop protection in Crete, Greece, is the control of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) with chemical insecticides owing to the rapid development of resistance. The aim of this study was to investigate the establishment of resistance and the underlying mechanisms to major insecticide classes with classical bioassays and known biochemical resistance markers. RESULTS: During a 2005–2007 survey, 53 Q biotype populations were collected. Application history records showed extensive use of neonicotinoids, organophosphates, carbamates and pyrethroids. High resistance levels were identified in the majority of populations (>80%) for imidacloprid (RF: 38–1958×) and α‐cypermethrin (RF: 30–600×). Low resistance levels (RF < 12) were observed for pirimiphos‐methyl. A strong correlation between resistance to imidacloprid and the number of applications with neonicotinoids was observed. Significant correlations were observed between COE and P450‐dependent monoxygenase activity with resistance to α‐cypermethrin and imidacloprid respectively. A propoxur‐based AChE diagnostic test indicated that iAChE was widespread in most populations. Resistance levels for α‐cypermethrin were increased when compared with a previous survey (2002–2003). Differentiation of LC₅₀ values between localities was observed for imidacloprid only. CONCLUSION: Bemisia tabaci resistance evolved differently in each of the three insecticides studied. Imidacloprid resistance seems less established and less persistent than α‐cypermethrin resistance. The low resistance levels for pirimiphos‐methyl suggest absence of cross‐resistance with other organophosphates or carbamates used. Copyright © 2008 Society of Chemical Industry  相似文献   

Transgenic poplar with enhanced growth by introduction of the ugt and acb genes     

Rurick Salyaev  Natalya Rekoslavskaya  Anastasia Chepinoga  Sergio Mapelli  R. Pacovsky 《New Forests》2006,32(2):211-229

The transgenic poplar (Populus tremula L.) was obtained by transfer of the ugt and acb genes via triparental mating, which was employed to deliver large fragments of TDNA as a cluster. Freshly harvested seeds of local poplar were placed on MS agar medium and plantlets were obtained. After 1 year of subcultivation, plantlets were infected with a transconjugant of triparental mating with target ugt and acb genes into axillary buds. The transformed sprouts so obtained were cut and subcultivated on agar medium with an addition of 0.6 mg/l indole-3-butyric acid as an auxin source. The transformed sprouts showed GUS activity and resistance to gentamycin and kanamycin. The integrity of the target ugt and acb genes into poplar genome was demonstrated via PCR and Southern blot hybridisation. The transgenic poplar plants revealed a higher growth energy, corresponding to a higher content of IAA as opposed to control plants. Both transgenic and non-transformed plants were potted into soil for outdoor acclimatisation and subsequently transferred to earth in beds. Growing outside during 3 years, the transgenic poplar demonstrated a higher growth rate with fast bud and branch development.  相似文献   

Dietary patterns and survival of older Europeans: the EPIC-Elderly Study (European Prospective Investigation into Cancer and Nutrition)     

Bamia C  Trichopoulos D  Ferrari P  Overvad K  Bjerregaard L  Tjønneland A  Halkjaer J  Clavel-Chapelon F  Kesse E  Boutron-Ruault MC  Boffetta P  Nagel G  Linseisen J  Boeing H  Hoffmann K  Kasapa C  Orfanou A  Travezea C  Slimani N  Norat T  Palli D  Pala V  Panico S  Tumino R  Sacerdote C  Bueno-de-Mesquita HB  Waijers PM  Peeters PH  van der Schouw YT  Berenguer A  Martinez-Garcia C  Navarro C  Barricarte A  Dorronsoro M  Berglund G  Wirfält E  Johansson I  Johansson G  Bingham S  Khaw KT  Spencer EA  Key T  Riboli E  Trichopoulou A 《Public health nutrition》2007,10(6):590-598

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First description of demodicosis in 12 galagos (Galago senegalensis)     

Kuznetsova E  Vysokikh A  Bourdeau P 《Veterinary dermatology》2012,23(1):61-4, e14

Twelve Galago senegalensis from the Moscow Zoo were presented with papular to nodular (2-11 mm) lesions on the pinnae, containing a white, waxy material. Microscopic examination revealed large numbers of mites consistent with the morphology of Demodex spp. mites. Nine animals were treated with ivermectin, 600 μg/kg/day topically, orally or subcutaneously for 3-10 months, while one remained untreated. All the treated animals achieved clinical remission. The control animal was still affected and died 11 months later due to pneumonia and possible eosinophilic leukaemia. No adverse effects were noted in any animals during the treatment. No animal relapsed in the 13-19 months follow-up period. To the authors' knowledge, this is the first report of demodicosis in G. senegalensis. The use of ivermectin in G. senegalensis was safe, although its effectiveness in the treatment of demodicosis needs further investigation.  相似文献   

Effects of feeding with different live preys on the lipid composition,growth and survival of Octopus vulgaris paralarvae     

Diana B. Reis  Anastasia Shcherbakova  Rodrigo Riera  Virgina M. Martín  Pedro Domingues  Jos P. Andrade  Pablo Jimnez‐Prada  Covadonga Rodríguez  Antnio V. Sykes  Eduardo Almansa 《Aquaculture Research》2021,52(1):105-116

To move forward in the farming of Octopus vulgaris paralarvae, it is necessary to search for a live prey easy to obtain and maintain in the laboratory that meets the nutritional requirements of the octopus paralarvae and adapts to its predatory behaviour. Grapsus adscensionis zoeae (Crustacea, Decapoda) seems to fulfil most of these targets, and it was herein used to deepen knowledge of paralarvae lipid requirements and composition, growth and survival. To this purpose, the effects of feeding with Grapsus zoeae as sole prey were compared with Artemia at two different stages (nauplii and juveniles), which also differed in their lipid profiles. After 15 days of feeding, the best growth and survival of paralarvae was obtained in the Grapsus group, and no differences were observed between both Artemia groups. Triacylglycerides storage in paralarvae seemed to be co‐related with a lower growth and survival, but not with its prey levels. Contrarily, sterol ester levels were higher in paralarvae fed Grapsus, reflecting its content in the prey. The best paralarval viability was related to higher levels of 22:6n‐3 (DHA) and 20:4n‐6 (ARA), also reflecting its higher content in the prey. On the other hand, neither the 20:5n‐3 (EPA) levels in the prey nor in paralarvae were related to growth or survival. The implications of these results are discussed considering the lipid requirements of O. vulgaris paralarvae.  相似文献