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31.
Carmen?Rossini Alexander?Bezzerides Andrés?González Maria?Eisner Thomas?EisnerEmail author 《Chemoecology》2003,13(4):199-205
Summary. Evidence is presented that pyrrolizidine alkaloid acquired
by Utetheisa ornatrix (Lepidoptera, Arctiidae) as a larva
from Crotalaria foodplants is incorporated in part into the scales
of the adult. A single forewing of a male or female moth may contain in
the order of 6 to 13 g monocrotaline in its scale cover or about 1 to 2%
of the moths systemic monocrotaline content. Based on estimates of the number
of scales per forewing, the monocrotaline content of individual scales is calculated
to be in the order of 0.1 and 0.2 ng monocrotaline per male and female scale,
respectively. This amounts to concentrations of about 1 and 3%, values roughly at
a par with the average systemic concentration (0.5-0.6%) previously determined
for monocrotaline in Utetheisa. It is argued that the presence of pyrrolizidine alkaloid
in the moths scale coating could account for the promptness with which adult Utetheisa are
rejected by spiders. It is suggested further that chemical impregnation of scales with substances
deterrent to predators may be more widespread among insects than generally assumed. 相似文献
32.
Euglena gracilis as a model for the study of Cu and Zn toxicity and accumulation in eukaryotic cells
Marcelo Einicker-Lamas Gustavo Antunes Mezian Thiago Benevides Fernandes Fabio Leandro S. Silva Flvio Guerra Kildare Miranda Marcia Attias Mecia M. Oliveira 《Environmental pollution (Barking, Essex : 1987)》2002,120(3)
We have observed the effect of copper and zinc on the biology of Euglena gracilis. The cells displayed different sensitivities to these metals, as the apparent LC50 for Cu2+ was 0.22 mM, and for Zn2+ it was 0.88 mM. While Zn2+ was able to increase cell proliferation even at 0.1 mM, the minimal CuCl2 concentration tested (0.02 mM) was sufficient to impair cell division. Higher concentrations of these metals not only inhibited cell division in a concentration-dependent manner, but also interfered with the metabolism of E. gracilis. A higher accumulation of proteins and lipids per cell was observed at the DI50 concentration for metal-treated cells. These results suggest that the test concentration of both metals leads to a failure in completing cell division. Ultrastructural analysis indicated a chloroplast disorganization in copper-treated cells, as well as the presence of electron dense granules with different shapes and sizes inside vacuoles. Microanalysis of these granules indicated an accumulation of copper, thus suggesting a detoxification role played by the vacuoles. These results indicate that E. gracilis is an efficient biological model for the study of metal poisoning in eukaryotic cells. They also indicate that copper and zinc (copper being more poisonous) had an overall toxic effect on E. gracilis and that part of the effect can be ascribed to defects in the structure of chloroplast membranes. 相似文献
33.
34.
The most recent intervention on the coastline of Espinho, located on the Portuguese West Atlantic coast, was part of the General
Plan for Coastal Protection in 1980/81. As a result, two unusually large groins/headlands were built which were reinforced
and enlarged in 1997, slightly changing their geometry and orientation. However, due to the decreased sediment supply from
the north and the impact of energetic sea conditions common to the northwest coast of Portugal the coastal evolution has not
developed as desired, although in general terms the initial expectations were fulfilled. The numerical modelling of the Espinho
coastline using SMC software focused on both hydrodynamic and hydromorphological aspects. The purpose of this study is to
analyse the most vulnerable areas of the Espinho seafront for current velocities and littoral drift, as well as to confirm
the effectiveness of the two groins in terms of coastal protection. To achieve this, various simulations were performed, taking
into account diverse sea conditions. 相似文献
35.
The management of small-scale freshwater fisheries in Amazon has been based usually on surveys of urban markets, while fisheries
of rural villages have gone unnoticed. We compared the fishing characteristics (catch, effort and selectivity) between an
urban market and five small villages in the Lower Tocantins River (Brazilian Amazon), downstream from a large reservoir. We
recorded 86 and 601 fish landings in the urban market and villages, respectively, using the same methodology. The urban fishers
showed higher catch per unit of effort, higher amount of ice (related to a higher fishing effort, as ice is used to store
fish catches) and larger crew size per fishing trip, but village fishers had a higher estimated annual fish production. Conversely,
urban and village fishers used similar fishing gear (gillnets) and the main fish species caught were the same. However, village
fishers showed more diverse strategies regarding gear, habitats and fish caught. Therefore, although it underestimated the
total amount of fish caught in the Lower Tocantins River region, the data from the urban market could be a reliable indicator
of main fish species exploited and fishing gear used by village fishers. Monitoring and management should consider the differences
and similarities between urban and rural fisheries, in Amazon and in other tropical regions. 相似文献
36.
37.
Guimarães Barbara Maria Ribeiro Scatolino Mário Vanoli Martins Maria Alice Ferreira Saulo Rocha Mendes Lourival Marin Lima José Tarcísio Junior Mario Guimarães Tonoli Gustavo Henrique Denzin 《Environmental science and pollution research international》2022,29(6):8665-8683
Environmental Science and Pollution Research - The growing demand for products with lower environmental impact and the extensive applicability of cellulose nanofibrils (CNFs) have received... 相似文献
38.
Schmitt Odair J. Andriolo Jerônimo L. Silva Isley C. B. Tiecher Tadeu L. Chassot Tatiane Tarouco Camila Peligrinotti Lourenzi Cledimar Rogério Nicoloso Fernando Teixeira Marchezan Carina Casagrande Cleiton Renato Drescher Gerson Laerson Kreutz Márcio André Brunetto Gustavo 《Environmental science and pollution research international》2022,29(29):44186-44198
Environmental Science and Pollution Research - Copper (Cu) can be toxic to vegetables when it is absorbed and accumulated at large concentrations, a fact that increases the risk of excessive... 相似文献
39.
Conservation practitioners, natural resource managers, and environmental stewards often seek out scientific contributions to inform decision-making. This body of science only becomes actionable when motivated by decision makers considering alternative courses of action. Many in the science community equate addressing stakeholder science needs with delivering actionable science. However, not all efforts to address science needs deliver actionable science, suggesting that the synonymous use of these two constructs (delivering actionable science and addressing science needs) is not trivial. This can be the case when such needs are conveyed by people who neglect decision makers responsible for articulating a priority management concern and for specifying how the anticipated scientific information will aid the decision-making process. We argue that the actors responsible for articulating these science needs and the process used to identify them are decisive factors in the ability to deliver actionable science, stressing the importance of examining the provenance and the determination of science needs. Guided by a desire to enhance communication and cross-literacy between scientists and decision makers, we identified categories of actors who may inappropriately declare science needs (e.g., applied scientists with and without regulatory affiliation, external influencers, reluctant decision makers, agents in place of decision makers, and boundary organization representatives). We also emphasize the importance of, and general approach to, undertaking needs assessments or gap analyses as a means to identify priority science needs. We conclude that basic stipulations to legitimize actionable science, such as the declaration of decisions of interest that motivate science needs and using a robust process to identify priority information gaps, are not always satisfied and require verification. To alleviate these shortcomings, we formulated practical suggestions for consideration by applied scientists, decision makers, research funding entities, and boundary organizations to help foster conditions that lead to science output being truly actionable. 相似文献
40.
The role of private rural properties for conserving native vegetation in Brazilian Southern Amazonia
Siqueira Auberto Ricaurte Luisa Fernanda Borges Guilherme Augusto Nunes Gustavo Manzon Wantzen Karl Matthias 《Regional Environmental Change》2018,18(1):21-32
Regional Environmental Change - The State of Mato Grosso in Brazil has undergone intensive land use changes over the past decades. Native ecosystems have been converted into agrosystems for the... 相似文献