Changes induced by malathion, methylparathion and parathion on membrane lipid physicochemical properties correlate with their toxicity

Perturbations induced by malathion, methylparathion and parathion on the physicochemical properties of dipalmitoylphosphatidylcholine (DPPC) were studied by fluorescence anisotropy of DPH and DPH-PA and by differential scanning calorimetry (DSC). Methylparathion and parathion (50 [mu]M) increased the fluorescence anisotropy evaluated by DPH-PA and DPH, either in gel or in the fluid phase of DPPC bilayers, but mainly in the fluid phase. Parathion is more effective than methylparathion. On the other hand, malathion had almost no effect. All the three xenobiotics displaced the phase transition midpoint to lower temperature values and broadened the phase transition profile of DPPC, the effectiveness following the sequence: parathion>methylparathion>>malathion. A shifting and broadening of the phase transition was also observed by DSC. Furthermore, at methylparathion/lipid molar ratio of 1/2 and at parathion/lipid molar ratio of 1/7, the DSC thermograms displayed a shoulder in the main peak, in the low temperature side, suggesting coexistence of phases. For higher ratios, the phase transition profile becomes sharp as the control transition, but the midpoint is shifted to the previous shoulder position. Conversely to methylparathion and parathion, malathion did not promote phase separation. The overall data from fluorescence anisotropy and calorimetry indicate that the degree of effect of the insecticides on the physicochemical membrane properties correlates with toxicity to mammals. Therefore, the in vivo effects of organophosphorus compounds may be in part related with their ability to perturb the phospholipid bilayer structure, whose integrity is essential for normal cell function.http://www.sciencedirect.com/science/article/B6T1T-42NY32W-K/1/9c5c8320a8dff42bbf122281b5056b8

Avaliação do comportamento humano nas organizações: uma proposta.

Referencial teórico; Proposta de instrumento de avaliação comportamental; Metodologia para operacionalização.bitstream/CNPTIA/11402/1/doc66.pdfAcesso em 28 maio 2007

Physiological and sensorial aspects of peach fruits cv. Chimarrita depending on the season and management of green pruning.

Made available in DSpace on 2018-01-11T23:32:07Z (GMT). No. of bitstreams: 1 LuisEduardoPODAVERDECHIMARRITA.pdf: 371835 bytes, checksum: e3f18ade57a63bec5503b96c84f41f1f (MD5) Previous issue date: 2018-01-10bitstream/item/170739/1/Luis-Eduardo-PODA-VERDE-CHIMARRITA.pd

Palatability of the Asian clam Corbicula fluminea (Müller 1774) in an invaded system

Biotic interactions such as predation may influence the success of invasive alien species (IAS). Although the Asian clam Corbicula fluminea is recognized as one of the most problematic aquatic IAS, few studies have investigated its use as a food resource. In this study, we aimed to investigate (i) the palatability of C. fluminea under natural (Minho River) and laboratory conditions and (ii) if C. fluminea submitted to different conditions (individuals from Lima and Minho Rivers) vary in palatability. Soft tissues from different Corbicula populations, plus soft tissues from a native clam, tuna and Corbicula shell powder were offered to consumers. Field assays were performed seasonally and laboratory assays only in summer; both assays also tested possible differences during distinct periods of the day. Overall, in natural conditions, the treatments containing C. fluminea had a low palatability. In laboratory assays, higher consumption (almost two times) was observed for Cyprinus carpio and Anguilla anguilla. Also, C. fluminea palatability was different between populations, with the treatment Corbicula Lima being more consumed than Corbicula Minho. Despite the low values of consumption in the field, laboratory results suggest that C. fluminea soft tissues can be a food resource to some species.This study was conducted as part of the project FRESCHO: Multiple implications of invasive species on Freshwater Mussel coextinction processes, supported by FCT (contract: PTDC/AGRFOR/1627/2014). MI is supported by a Post-doc grant (SFRH/BPD/90088/2012) from the Portuguese Foundation for Science and Technology—FCT through POPH/FSE funds. RS also acknowledge the support of the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER007569) funded by national funds through the FCT I.P and by the ERDF through the COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI)