832 research outputs found

    A DISCUSSION OF SOME ECOLOGICAL FACTORS AFFECTING COCCIDENCYRTUS MALLOI BLANCHARD (HYMENOPTERA: ENCYRTIDAE) AS A PARASITOID OF DIASPIDID SCALES UNDER GLASS IN FRANCE

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    A DISCUSSION OF SOME ECOLOGICAL FACTORS AFFECTING COCCIDENCYRTUS MALLOI BLANCHARD (HYMENOPTERA, ENCYRTIDAE) AS A PARASITOID OF DIASPIDID SCALES UNDER GLASS IN FRANCE. The encyrtid parasitoid Coccidencyrtus malloi Blanchard has been recorded in orchid glasshouses of south-eastern France where its diaspidid host, Diaspis boisduvalii Signoret (Hemiptera, Diaspididae), is sometimes a pest of ornamentals. In order to study its biology and potential as a biological control agent, it was cultured on a bromeliad and released into several hot temperate commercial houses. It was found to have a very restricted distribution which appeared to be determined by deep shade and very high humidities. Key words: Argentina, Boisduval scale, parasitoid development, thelytokous parthenogenesis, Diaspis bromeliae, D, coccois, Laeliocattleya, Vriesea, Aechmea, Cattleya, Citrullus, Cymbidium, Coccos, Dendrobium, Neodypsis, Hohenbergia

    A STUDY OF TWO PLAGIOMERUS SPECIES (HYMENOPTERA: ENCYRTIDAE) PARASITISING DIASPIDID SCALES (COCCOIDEA) IN GLASSHOUSES IN FRANCE

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    A STUDY OF TWO PLAGIOMERUS SPECIES (HYMENOPTERA: ENCYRTIDAE) PARASITISING DIASPIDID SCALES (COCCOIDEA) IN GLASSHOUSES IN FRANCE. Plagiomerus diaspidis Crawford was imported from Tenerife (Canary Islands, Spain) and released experimentally as a biological control agent against Diaspis echinocacti (Bouché) (Hemiptera, Diaspididae) within a cactus glasshouse in south-eastern France but it failed to provide control, apparently due to very weak powers of dispersal. A second undescribed Plagiomerus was found in a wet tropical greenhouse in the same region of France and was thought to be a potential biocontrol agent of Diaspididae. It was found to parasitise the three Diaspis species (D. boisduvalii Signoret, D. coccois (Lichtenstein) and D. bromeliae (Kerner)) present in the greenhouse, although it failed to control them. Both parasitoid species reproduced by thelytokous parthenogenesis. Key words: development, Boisduval scale, preferred environments, USA, Mexico, Azerbaidjan, Opuntia, Strelitzia, Calanthe, palm

    Elucidation of the compatible interaction between banana and Meloidogyne incognita via high-throughput proteome profiling

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    With a diverse host range, Meloidogyne incognita (root-knot nematode) is listed as one of the most economically important obligate parasites of agriculture. This nematode species establishes permanent feeding sites in plant root systems soon after infestation. A compatible host-nematode interaction triggers a cascade of morphological and physiological process disruptions of the host, leading to pathogenesis. Such disruption is reflected by altered gene expression in affected cells, detectable using molecular approaches. We employed a high-throughput proteomics approach to elucidate the events involved in a compatible banana- M. incognita interaction. This study serves as the first crucial step in developing natural banana resistance for the purpose of biological-based nematode management programme. We successfully profiled 114 Grand naine root proteins involved in the interaction with M. incognita at the 30th- and 60th- day after inoculation (dai). The abundance of proteins involved in fundamental biological processes, cellular component organisation and stress responses were significantly altered in inoculated root samples. In addition, the abundance of proteins in pathways associated with defence and giant cell maintenance in plants such as phenylpropanoid biosynthesis, glycolysis and citrate cycle were also implicated by the infestation

    Transcriptional responses are oriented towards different components of the rearing environment in two Drosophila sibling species

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    Background The chance to compare patterns of differential gene expression in related ecologically distinct species can be particularly fruitful to investigate the genetics of adaptation and phenotypic plasticity. In this regard, a powerful technique such as RNA-Seq applied to ecologically amenable taxa allows to address issues that are not possible in classic model species. Here, we study gene expression profiles and larval performance of the cactophilic siblings Drosophila buzzatii and D. koepferae reared in media that approximate natural conditions and evaluate both chemical and nutritional components of the diet. These closely related species are complementary in terms of host-plant use since the primary host of one is the secondary of the other. D. koepferae is mainly a columnar cactus dweller while D. buzzatii prefers Opuntia hosts. Results Our comparative study shows that D. buzzatii and D. koepferae have different transcriptional strategies to face the challenges posed by their natural resources. The former has greater transcriptional plasticity, and its response is mainly modulated by alkaloids of its secondary host, while the latter has a more canalized genetic response, and its transcriptional plasticity is associated with the cactus species. Conclusions Our study unveils a complex pleiotropic genetic landscape in both species, with functional links that relate detox responses and redox mechanisms with developmental and neurobiological processes. These results contribute to deepen our understanding of the role of host plant shifts and natural stress driving ecological specialization

    Attempts to eradicate two Pelargonium viruses (PFBV and PLPV) by meristem culture and shoot-tip cryotherapy

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    Attempts to eradicate the Pelargonium flower break virus (PFBV) and Pelargonium line pattern virus (PLPV) by meristem culture and apex “droplet-vitrification” cryopreservation was carried out using 5 different cultivars. A simple meristem culture did not permit to eliminate PFBV and only 15% of Pelargonium x hortorum ‘Stellar Artic’ plants regenerated from meristems was PLPV-ELISA-negative. Plants regenerated from cryopreserved apices were tested by DAS-ELISA after a 3-month growing period. Viruses were not detected in 25 and 50% of the tested plants for PFBV and PLPV respectively. Immunolocalisations were carried out for virus localisation in apices from greenhouse plants (control) and vitroplants regenerated after meristem culture or cryopreservation. Immunolocalisations realised on control explants excised from DAS-ELISA positive plants showed that PFBV and PLPV were present in the apices, even in the meristematic dome. However, viral particles were more numerous in the cells of the basal zone than in the more meristematic ones. Immunolocalisations realised on apices from the DAS-ELISA negative cryoregenerated plants showed the viruses were still present. Our results firstly demonstrated that PFBV and PLPV are even present inside meristematic cells and secondly that cryopreservation could decrease their amount in Pelargonium plants but without eliminating them totally. More knowledge on virus behaviour during cryopreservation processes could optimize the management of genetic resources using this conservation method

    Pancreaticogastrostomy After Pancreatoduodenectomy

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    The aim of this study was to evaluate the place of pancreaticogastrostomy (PG) in reducing pancreatic fistula after pancreatoduodenectomy. From January 1988 to June 1991, 32 consecutive patients (mean age, 57 years) were operated on, 25 for malignant disease (78%). The pancreatic remnant was normal in 17 patients (53%) and sclerotic in the others. There was one operative death (3.1%) unrelated to PG. Post-operative complications occurred in five patients (16%). Only two complications were related to PG: 1 patient had anastomotic intra-gastric bleeding and was reoperated on, 1 patient with a normal pancreatic remnant developed a pancreatic fistula (3.1%) treated conservatively

    In vitro cryopreservation of date palm caulogenic meristems

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    Cryopreservation is the technology of choice not only for plant genetic resource preservation but also for virus eradication and for the efficient management of large-scale micropropagation. In this chapter, we describe three cryopreservation protocols (standard vitrification, droplet vitrification, and encapsulation vitrification) for date palm highly proliferating meristems that are initiated from vitro-cultures using plant growth regulator-free MS medium. The positive impact of sucrose preculture and cold hardening treatments on survival rates is significant. Regeneration rates obtained with standard vitrification, encapsulation-vitrification, and droplet-vitrification protocols can reach 30, 40, and 70%, respectively. All regenerated plants from non-cryopreserved or cryopreserved explants don't show morphological variation by maintaining genetic integrity without adverse effect of cryogenic treatment. Cryopreservation of date palm vitro-cultures enables commercial tissue culture laboratories to move to large-scale propagation from cryopreserved cell lines producing true-to-type plants after clonal field-testing trials. When comparing the cost of cryostorage and in-field conservation of date palm cultivars, tissue cryopreservation is the most cost-effective. Moreover, many of the risks linked to field conservation like erosion due to climatic, edaphic, and phytopathologic constraints are circumvented. (Résumé d'auteur
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