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

Seasonal proteome variation in intertidal shrimps under a natural setting: connecting molecular networks with environmental fluctuations

The ability of intertidal organisms to maintain their performance via molecular and physiological adjustments under low tide, seasonal fluctuations and extreme events ultimately determines population viability. Analyzing this capacity in the wild is extremely relevant since intertidal communities are under increased climate variability owing to global changes. We addressed the seasonal proteome signatures of a key intertidal species, the shrimp Palaemon elegans, in a natural setting. Shrimps were collected during spring and summer seasons at low tides and were euthanized in situ. Environmental variability was also assessed using hand-held devices and data loggers. Muscle samples were taken for 2D gel electrophoresis and protein identification through mass spectrometry. Proteome data revealed that 55 proteins (10.6% of the proteome) significantly changed between spring and summer collected shrimps, 24 of which were identified. These proteins were mostly involved in cytoskeleton remodelling, energy metabolism and transcription regulation. Overall, shrimps modulate gene expression leading to metabolic and structural adjustments related to seasonal differences in the wild (i.e. abiotic variation and possibly intrinsic cycles of reproduction and growth). This potentially promotes performance and fitness as suggested by the higher condition index in summer-collected shrimps. However, inter-individual variation (% coefficient of variation) in protein levels was quite low (min-max ranges were 0.6-8.3% in spring and 1.2-4.8% in summer), possibly suggesting reduced genetic diversity or physiological canalization. Protein plasticity is relevant to cope with present and upcoming environmental variation related to anthropogenic forcing (e.g. global change, pollution) but low inter-individual variation may limit evolutionary potential of shrimp populations.publishe

Cytotoxicity and Membrane Interaction of Tamoxifen as Affected by Ca2+ and Mg2+: Use of a Bacterial Model System

A strain of Bacillus stearothermophilus was used as a model to study the interaction of tamoxifen (TAM) with the membrane and the cytostatic antiproliferative effects not related to estrogen binding. TAM inhibits the growth of B. stearothermophilus as a function of concentration. The supplementation of the growth medium with Ca2+ or Mg2+ partially relieves the growth inhibition by TAM, allowing growth at TAM concentrations that fully impair growth in the basal medium. Fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and of its propionic acid derivative (DPH-PA) reveals opposite effects induced by TAM and Ca2+. The addition of Ca2+ to liposomes of bacterial lipids promoted physical ordering as opposed to disordering induced by TAM. Thus, it is predictable that growth impairment induced by TAM is mediated through perturbations at the membrane level.http://www.sciencedirect.com/science/article/B6TCP-3X3K8KK-Y/1/c91ad40c71c69da7245d8f09c634d28

Profile of vegetable consumers of Santo Antônio do Descoberto town, Goiás State, Brazil

A cidade de Santo Antônio do Descoberto está localizada a 46 km de Brasília e grande parte da sua população vive abaixo da linha de pobreza. Neste trabalho, o perfil e o padrão de consumo de hortaliças na cidade foi avaliado. Setenta e três consumidores freqüentadores do Mercado Municipal e 30 de uma região periférica (Bairro do Queiroz) foram entrevistados para a coleta de informações sobre hortaliças adquiridas no dia, número de indivíduos na família e renda familiar. No Mercado Municipal, 92% das famílias adquiriam hortaliças semanalmente e consumiam os produtos em no máximo três dias. Trinta e cinco por cento das famílias tinham renda que as situava baixo da linha de pobreza. Alface, tomate e batata eram os produtos mais comumente consumidos. Por outro lado, na região periférica, 86% das famílias entrevistadas estavam abaixo da linha de pobreza e apenas 44% delas adquiriam hortaliças semanalmente. Alface e cebola eram os produtos mais consumidos e nenhuma família comprava tomate, provavelmente devido ao preço elevado deste produto. O tipo e freqüência de hortaliças adquiridos são influenciados pela renda familiar, com as famílias mais pobres consumindo menos. ________________________________________________________________________________ ABSTRACTSanto Antônio do Descoberto is located 46 km away from Brasília and the great majority of its population lives under the poverty line. In this work, vegetable consumption and consumers profile of Santo Antônio do Descoberto town were evaluated. Seventy consumers in the Municipal Market and 30 in a peripheral region ('Bairro do Queiroz') were interviewed. Information about vegetables bought in that day, number of people in the family and family income were obtained. The results showed that 92% of the families interviewed at the Municipal Market bought vegetables weekly and consumed them in nearly three days; 35% of the families were under the poverty line. Lettuce, tomato and potato were the most consumed vegetables. On the other hand, in the peripheral region, only 44% of the families bought vegetables weekly; 86% of the families were under the poverty line. Lettuce and onion were the main vegetables consumed in the region. None of the families consumed tomato, probably due to its high cost. The type and frequency of vegetable consumption was influenced by the families' income, where poor families consumed less vegetables