Nasturtium leaf compounds, diphenyl disulfide and lyral, against Atta sexdens (Hymenoptera: Formicidae) and their symbiotic fungi.

Social insect pests, particularly leaf-cutting ants, present a considerable challenge in terms of control. Leaf-cutting ants are significant agricultural, forestry, and pasture pests, and understanding their behavior and defense mechanisms is essential for managing their colonies effectively. While toxic ant baits are a primary control method, the limited availability of effective insecticides and concerns over their hazardous nature has spurred the search for alternative solutions, particularly natural compounds, which aligns with the goals of forest certification groups. In the light of previous evidence demonstrating the efficacy of nasturtium leaves (Tropaeolum majus L. (Brassicales: Tropaeolaceae)) in suppressing leaf-cutting ant colonies, this study investigates 2 active components of nasturtium leaf extracts: diphenyl disulfide and lyral. We tested their impact on Atta sexdens (L.) (Hymenoptera: Formicidae), the most prevalent leaf-cutter ant species in Brazil, and their symbiotic fungus, Leucoagaricus gongylophorus (Möller) Singer (Agaricales: Agaricaceae). We conducted experiments with increasing concentrations of diphenyl disulfide and lyral, assessing their effects on the symbiotic fungus and on forager workers and gardeners of A. sexdens colonies. Our findings revealed no fungicidal activity, and ant mortality was minimal in both topical and ingestion bioassays with the exception of gardeners topically exposed to diphenyl sulfide. Furthermore, the compounds did not affect leaf ingestion, but diphenyl disulfide did increase interactions among foragers. These results suggest that neither diphenyl disulfide nor lyral are the primary contributors to the suppression of leaf-cutting ant colonies by nasturtium leaves. However, they may enhance the formicidal activity of other compounds present in nasturtium leaves.

Chronic exposure to a common biopesticide is detrimental to individuals and colonies of the paper wasp Polistes versicolor.

Risk assessments of agrochemicals on non-target insects are biased in studies with surrogate groups, such as pollinators. In social insects, such investigations are generally restricted to lethal tests with adults maintained individually, simulating a non-realistic scenario. Here, we performed a holistic approach to resemble a chronic field exposure of Polistes versicolor (Hymenoptera: Vespidae) to a common biopesticide. These wasps are predators that perform biological control in the agroecosystems. Wasps were chronically subjected to the ingestion of different concentrations of azadirachtin. The neonicotinoid imidacloprid was used as a positive control. For the first time, we demonstrated that the biopesticide azadirachtin is detrimental for individual and colony survival and impairs colony reproduction of a social wasp maintained in the laboratory. Our data also indicated that neonicotinoid imidacloprid is harmful to wasps and their colonies. Therefore, the concomitant use of azadirachtin and paper wasps in integrated pest management strategies should be carefully evaluated, because the constant use of this pesticide can be detrimental for social wasps, possibly reducing biological control.

Toxicological assessments of agrochemical effects on stingless bees (Apidae, Meliponini).

Bee pollination is crucial for ecosystem maintenance and crop production. The ubiquity of bee pollinators in agricultural landscapes frequently results in their exposure to agrochemicals, which has been associated with their decline. Stingless bees are wild pollinators restricted to the Pantropical region, and like honey bees, are suffering colony losses. However, stingless bees and honey bees do not show the same behaviors, therefore, methods used for risk assessment of honey bees cannot be utilized on stingless bees. Herein, we describe protocols to standardize methods that allow for the exploration of lethal and sublethal effects of agrochemicals via acute and chronic exposure of stingless bees. The in vitro rearing used for chronic exposure from the egg to the adult stage proved to be effective in obtaining relevant screenings. In addition, we performed a meta-analysis and summarized the results of toxicological studies conducted with the protocols described. The meta-analyses indicated a reduction in survival under acute and chronic exposures to agrochemicals, and revealed that our protocols for toxicological assessments did not have publication bias for either acute or chronic exposure. These findings proved that these standardized protocols are reliable for toxicological research on stingless bee.

Primary cardiac angiosarcoma: case report of a rare neoplasia / Angiossarcoma cardíaco primário: relato de caso de uma rara neoplasia

ABSTRACT This article reports a case of primary cardiac angiosarcoma and a brief review is provided. A 44-year-old male patient was suspected of having myxoma in the right atrium. The tumor, on pathology examination, was shown to be a cardiac angiosarcoma. In the postoperative period, the patient developed a cardiac tamponade, requiring reoperation and evolving to death. Angiosarcomas are malignant tumors characterized by a devastating clinical course. They have a predilection for the right atrium, occurring between the third and fifth decades of life, with a male preponderance. Because of its rarity, the ideal treatment has not been identified yet.

RESUMO Este artigo ilustra um caso de angiossarcoma primário cardíaco acompanhado de uma revisão dessa rara neoplasia. Relatamos o caso de um paciente do sexo masculino, 44 anos, com suspeita de mixoma em átrio direito. O tumor, ao exame anatomopatológico, mostrou tratar-se de um angiossarcoma cardíaco. No pós-operatório, o paciente cursou com tamponamento cardíaco, necessitando ser reoperado e evoluindo a óbito. Angiossarcomas são tumores malignos caracterizados por curso clínico devastador. Apresentam predileção pelo átrio direito, e ocorrem entre a terceira e a quinta década de vida, com preponderância no sexo masculino. Devido a sua raridade, o tratamento ideal ainda não está bem estabelecido.

Biopesticide-induced behavioral and morphological alterations in the stingless bee Melipona quadrifasciata.

Because of their natural origin, biopesticides are assumed to be less harmful to beneficial insects, including bees, and therefore their use has been widely encouraged for crop protection. There is little evidence, however, to support this ingrained notion of biopesticide safety to pollinators. Because larval exposure is still largely unexplored in ecotoxicology and risk assessment on bees, an investigation was performed on the lethal and sublethal effects of a diet treated with 2 bioinsecticides, azadirachtin and spinosad, on the stingless bee, Melipona quadrifasciata, which is one of the most important pollinators in the Neotropics. Survival of stingless bee larvae was significantly compromised at doses above 210 ng a.i./bee for azadirachtin and 114 ng a.i./bee for spinosad. No sublethal effect was observed on larvae developmental time, but doses of both compounds negatively affected pupal body mass. Azadirachtin produced deformed pupae and adults as a result of its insect growth regulator properties, but spinosad was more harmful and produced greater numbers of deformed individuals. Only spinosad compromised walking activity of the adult workers at doses as low as 2.29 ng a.i./bee, which is 1/5000 of the maximum field recommended rate. In conclusion, the results demonstrated that bioinsecticides can pose significant risks to native pollinators with lethal and sublethal effects; future investigations are needed on the likelihood of such effects under field conditions.

Early experience with off-the-shelf endografts using a zone 0 proximal landing site to treat the ascending aorta and arch.

OBJECTIVE: Acute type A aortic syndromes and its chronic complications are fatal diseases traditionally treated by open surgery, with high mortality rates. An endovascular approach to the ascending aorta could reduce the morbidity and mortality associated with open surgery. Our aim was to report our initial experience in treating ascending aortic pathology using commercially available descending thoracic endografts. METHODS: From 2007 to 2012, 69 patients presented to our center in Belo Horizonte, Brazil, with acute type A aortic syndrome or its chronic complications. Of the 69 patients, 8 high-risk patients had suitable anatomy, and 7 agreed to participate in the present study. RESULTS: Of the 7 patients, 4 had penetrating ulcers, 2 had acute dissections, and 1 had chronic dissection with an aneurysm. The technical success rate was 87%, with 1 intraoperative death from acute aortic valve insufficiency. The proximal landing zone was, on average, 21 mm above the aortic valve in all patients. Three patients required intraoperative cervical debranching due to a lesion in the distal third of the ascending aorta, compromising the supra-aortic branches. The distal landing zone was at zone 0 in 4 patients, zone 2 in 1 patient, and in zone 4 in 2 patients. The mean follow-up was 26.3 months. Two repeat dissections developed an average of 2 months after treatment. Both presented with acute dissection that was treated with additional open surgery and both patients survived. Thereafter, no patient had presented again with an acute aortic syndrome or other referable symptoms. CONCLUSIONS: Endovascular treatment of the ascending aorta is feasible. We had 4 good mid-term results in 7 patients who had presented with penetrating ulcers or aneurysm formation. Acute dissections seem to be more unstable, and additional research is mandatory.