36 research outputs found

    Genetic elimination of field-cage populations of Mediterranean fruit flies

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    The Mediterranean fruit fly (medfly, Ceratitis capitata Wiedemann) is a pest of over 300 fruits, vegetables and nuts. The sterile insect technique (SIT) is a control measure used to reduce the reproductive potential of populations through the mass release of sterilized male insects that mate with wild females. However, SIT flies can display poor field performance, due to the effects of mass-rearing and of the irradiation process used for sterilization. The development of female-lethal RIDL (release of insects carrying a dominant lethal) strains for medfly can overcome many of the problems of SIT associated with irradiation. Here, we present life-history characterizations for two medfly RIDL strains, OX3864A and OX3647Q. Our results show (i) full functionality of RIDL, (ii) equivalency of RIDL and wild-type strains for life-history characteristics, and (iii) a high level of sexual competitiveness against both wild-type and wild-derived males. We also present the first proof-of-principle experiment on the use of RIDL to eliminate medfly populations. Weekly releases of OX3864A males into stable populations of wild-type medfly caused a successive decline in numbers, leading to eradication. The results show that genetic control can provide an effective alternative to SIT for the control of pest insects

    Component-based architectures for computer vision systems

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    Research performed in the field of computer vision has steadily ignored recent advances in programming tools and techniques, relying on well-established traditional methods, such as Unix-based C programming. While this can certainly be effective, modern computer vision research may benefit significantly from the new tools and technologies that have recently become available. This paper addresses the use of component-based programming methods and proposes a model loosely based on 3-tier architectures, for the creation of robust and reusable computer vision systems, in order to improve code modularity and reusability, and to ultimately foster cooperation between researchers in the field. It outlines a basic design strategy and exposes the benefits and drawbacks of migrating to component-based code. The model is used to build a component-driven framework that is designed based on the principles of 3-tier applications. Its purpose is to aid in the creation and maintenance of stable, dependable testing and development environments. We have listed the main advantages of this approach and have concluded that although the learning curve for the programming skills required is steep, the benefits to be reaped are worth it

    Improving olive fruit fly Bactrocera oleae (Diptera : Tephritidae) adult and larval artificial diets, microflora associated with the fly and evaluation of a transgenic olive fruit fly strain

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    Research on the olive fruit fly Bactrocera oleae (Rossi) – rearing simplification, insect microflora and transgenic strain evaluation – yielded several findings: (1) incorporation of antibiotics in the adult diet is evidently not needed; (2) colonization appears to be easier when wild adults are collected from the field instead of using mature larvae emerging from field-collected infested olives; (3) a combination of standard solid starter with liquid (no cellulose powder) finisher impregnated in synthetic sponge larval diets was more promising compared with all-liquid diets; (4) molecular analysis revealed extensive differences in bacterial species associated with the fly between laboratory flies and strains from different olive varieties, as well as between strains originating from different seasons of the year; (5) when an enhanced green fluorescent protein transgenic strain was compared with the standard long mass-reared strain, it proved significantly inferior according to all quality control tests applied, i.e. egg production, egg hatch, larval-stage duration, pupal recovery, pupal weight, adult emergence and adult survival. The aforementioned findings are discussed in the context of mass rearing and quality requirements for more successful implementation of the sterile insect technique against this pest.9 page(s

    Control of the olive fruit fly using genetics-enhanced sterile insect technique

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    Abstract Background The olive fruit fly, Bactrocera oleae, is the major arthropod pest of commercial olive production, causing extensive damage to olive crops worldwide. Current control techniques rely on spraying of chemical insecticides. The sterile insect technique (SIT) presents an alternative, environmentally friendly and species-specific method of population control. Although SIT has been very successful against other tephritid pests, previous SIT trials on olive fly have produced disappointing results. Key problems included altered diurnal mating rhythms of the laboratory-reared insects, resulting in asynchronous mating activity between the wild and released sterile populations, and low competitiveness of the radiation-sterilised mass-reared flies. Consequently, the production of competitive, male-only release cohorts is considered an essential prerequisite for successful olive fly SIT. Results We developed a set of conditional female-lethal strains of olive fly (named Release of Insects carrying a Dominant Lethal; RIDL®), providing highly penetrant female-specific lethality, dominant fluorescent marking, and genetic sterility. We found that males of the lead strain, OX3097D-Bol, 1) are strongly sexually competitive with wild olive flies, 2) display synchronous mating activity with wild females, and 3) induce appropriate refractoriness to wild female re-mating. Furthermore, we showed, through a large proof-of-principle experiment, that weekly releases of OX3097D-Bol males into stable populations of caged wild-type olive fly could cause rapid population collapse and eventual eradication. Conclusions The observed mating characteristics strongly suggest that an approach based on the release of OX3097D-Bol males will overcome the key difficulties encountered in previous olive fly SIT attempts. Although field confirmation is required, the proof-of-principle suppression and elimination of caged wild-type olive fly populations through OX3097D-Bol male releases provides evidence for the female-specific RIDL approach as a viable method of olive fly control. We conclude that the promising characteristics of OX3097D-Bol may finally enable effective SIT-based control of the olive fly.</p

    Control of the olive fruit fly using genetics-enhanced sterile insect technique

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    Background: The olive fruit fly, Bactrocera oleae, is the major arthropod pest of commercial olive production, causing extensive damage to olive crops worldwide. Current control techniques rely on spraying of chemical insecticides. The sterile insect technique (SIT) presents an alternative, environmentally friendly and species-specific method of population control. Although SIT has been very successful against other tephritid pests, previous SIT trials on olive fly have produced disappointing results. Key problems included altered diurnal mating rhythms of the laboratory-reared insects, resulting in asynchronous mating activity between the wild and released sterile populations, and low competitiveness of the radiation-sterilised mass-reared flies. Consequently, the production of competitive, male-only release cohorts is considered an essential prerequisite for successful olive fly SIT. Results: We developed a set of conditional female-lethal strains of olive fly (named Release of Insects carrying a Dominant Lethal; RIDL®), providing highly penetrant female-specific lethality, dominant fluorescent marking, and genetic sterility. We found that males of the lead strain, OX3097D-Bol, 1) are strongly sexually competitive with wild olive flies, 2) display synchronous mating activity with wild females, and 3) induce appropriate refractoriness to wild female re-mating. Furthermore, we showed, through a large proof-of-principle experiment, that weekly releases of OX3097D-Bol males into stable populations of caged wild-type olive fly could cause rapid population collapse and eventual eradication. Conclusions: The observed mating characteristics strongly suggest that an approach based on the release of OX3097D-Bol males will overcome the key difficulties encountered in previous olive fly SIT attempts. Although field confirmation is required, the proof-of-principle suppression and elimination of caged wild-type olive fly populations through OX3097D-Bol male releases provides evidence for the female-specific RIDL approach as a viable method of olive fly control. We conclude that the promising characteristics of OX3097D-Bol may finally enable effective SIT-based control of the olive fly.8 page(s

    Docetaxel and carboplatin combination chemotherapy as outpatient palliative therapy in carcinoma of unknown primary: A multicentre Hellenic Cooperative Oncology Group phase II study

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    Introduction. Taxane/platinum combinations exhibit synergistic cytotoxicity and activity against a broad range of solid tumours. We sought to optimise the regimen as a suitable outpatient palliative treatment for cancer of unknown primary ( CUP). Patients and methods. Eligible CUP patients with adenocarcinoma or poorly differentiated carcinoma, performance status of 0-2, adequate organ function and assessable disease were treated with docetaxel 75 mg/m(2) and carboplatin at an area under the concentration time-curve (AUC) of 5, both as 30-minute intravenous infusions, every three weeks. Patients with isolated axillary adenopathy, squamous cell cervical or inguinal adenopathy and PSA or germ-cell serum tumour markers were excluded. Results. Forty-seven patients entered the trial, 24 with predominantly nodal disease or non-mucinous peritoneal carcinomatosis ( favourable risk) and 23 with visceral metastases ( unfavourable risk). A median of 6 cycles of chemotherapy were administered, with relative dose intensities of both drugs &gt; 90%. Response rates were 32% (46% in favourable risk, 17% in unfavourable), comparable to the activity of paclitaxel/platinum regimes, though complete remissions were seen only in favourable risk patients. Granulocyte-colony stimulating factor support was used in a third of treatment cycles. Toxicity was mild and manageable, with grade 3-4 neutropenia in 26% of patients, febrile neutropenia in 7% and severe non-hematologic side-effects in less than 8% of patients. No toxic deaths or severe neurotoxicity were seen. Median time to progression (TTP) and overall survival (OS) were 5.5 and 16.2 months respectively. Survival was driven mainly by favourable-risk patients (22.6 months), as those with visceral metastases had a poor median survival of only 5.3 months. Good performance status and low-volume disease predicted for superior outcome, while docetaxel relative dose-intensity was a positive prognosticator only in favourable-risk patients. Conclusions. One-hour docetaxel/carboplatin is a convenient, safe and effective outpatient palliative treatment for CUP patients, providing meaningful survival prolongation only in favourable-risk patients. Insights in the molecular biology of CUP are needed for the development of targeted therapeutic manipulations of malignant resistance and progression
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