RESUMO

Pomacea canaliculata is a mollusk potentially useful as a biomonitor species of freshwater quality. This work explores the ability of snail tissues and symbiotic corpuscles to bioconcentrate and depurate mercury, arsenic, and uranium. Adult snails cultured in metal-free reconstituted water were exposed for eight weeks (bioaccumulation phase) to water with Hg (2 µgL-1), As (10 µgL-1), and U (30 µgL-1) and then returned to the reconstituted water for other additional eight weeks (depuration phase). Elemental concentrations in digestive gland, kidney, symbiotic corpuscles and particulate excreta were determined by neutron activation analysis. The glandular symbiotic occupancy was measured by morphometric analysis. After exposure, the kidney showed the highest concentration of Hg, while the digestive gland accumulated mainly As and U. The subcellular distribution in symbiotic corpuscles was ∼71%, ∼48%, and ∼11% for U, Hg, and As, respectively. Tissue depuration between weeks 8 and 16 was variable amongst elements. At week 16, the tissue depuration of U was the highest (digestive gland = 92%; kidney = 80%), while it was lower for Hg (digestive gland = 51%; kidney = 53%). At week 16, arsenic showed a differential pattern of tissue depuration (digestive gland = 23%; kidney = 88%). The symbiotic detoxification of the three elements in excreta was fast between weeks 8 and 10 and it was slower after on. At the end of the depuration, each element distributed differentially in digestive gland and symbiotic corpuscles. Our findings show that symbiotic corpuscles, digestive gland and kidney P. canaliculata are sensitive places for biomonitoring of Hg, As and U.

Assuntos

RESUMO

Several studies of the behavior in the voltage and frequency fluctuations of the neural electrical activity have been performed. Here, we explored the particular association between behavior of the voltage fluctuations in the inter-spike segment (VFIS) and the inter-spike intervals (ISI) of F1 pacemaker neurons from H. aspersa, by disturbing the intracellular calcium handling with cadmium and caffeine. The scaling exponent α of the VFIS, as provided by detrended fluctuations analysis, in conjunction with the corresponding duration of ISI to estimate the determination coefficient R 2 (48-50 intervals per neuron, N = 5) were all evaluated. The time-varying scaling exponent α(t) of VFIS was also studied (20 segments per neuron, N = 11). The R 2 obtained in control conditions was 0.683 ([0.647 0.776] lower and upper quartiles), 0.405 [0.381 0.495] by using cadmium, and 0.151 [0.118 0.222] with caffeine (P < 0.05). A non-uniform scaling exponent α(t) showing a profile throughout the duration of the VFIS was further identified. A significant reduction of long-term correlations by cadmium was confirmed in the first part of this profile (P = 0.0001), but no significant reductions were detected by using caffeine. Our findings endorse that the behavior of the VFIS appears associated to the activation of different populations of ionic channels, which establish the neural membrane potential and are mediated by the intracellular calcium handling. Thus, we provide evidence to consider that the behavior of the VFIS, as determined by the scaling exponent α, conveys insights into mechanisms regulating the excitability of pacemaker neurons.

Assuntos

RESUMO

The terrestrial snail Helix pomatia (Gastropoda: Stylommatophora: Helicidae) is one of the largest gastropod species in Europe. This species is strictly protected in some European Union countries; however, at the same time, it is also farmed and commercialized for human consumption. Here, we describe 11 microsatellite markers that are very useful in population genetic studies for assessing the status of both wild and farmed populations of this species of community interest. The microsatellites were isolated using 454 pyrosequencing technologies and 11 primer pairs were selected and used for genotyping an H. pomatia population and also checked for cross-species amplification on H. lucorum and H. lutescens specimens. The number of alleles per locus ranged from 3 to 13 and observed heterozygosity was between 0.458 and 0.917. Seven of these loci were polymorphic in H. lucorum, and four in H. lutescens. This set of nuclear markers provides a powerful tool for population genetic studies of this species of community interest, and also for closely related species. The described microsatellite markers should also facilitate the identification of populations of conservation concern.

Assuntos

RESUMO

Coal remains an important source of energy, although the fuel is a greater environmental pollutant. Coal is a mixture of several chemicals, especially inorganic elements and polycyclic aromatic hydrocarbons (PAH). Many of these compounds have mutagenic and carcinogenic effects on organisms exposed to this mineral. In the town of Charqueadas (Brazil), the tailings from mining were used for landfill in the lower areas of the town, and the consequence is the formation of large deposits of this material. The purpose of this study was to evaluate the genotoxic potential of soil samples contaminated by coal waste in different sites at Charqueadas, using the land snail Helix aspersa as a biomonitor organism. Thirty terrestrial snails were exposed to different treatments: 20 were exposed to the soil from two different sites in Charqueadas (site 1 and 2; 10 in each group) and 10 non-exposed (control group). Hemolymph cells were collected after 24h, 5days and 7days of exposure and comet assay, micronucleus test, oxidative stress tests were performed. Furthermore, this study quantified the inorganic elements present in soil samples by the PIXE technique and polycyclic aromatic hydrocarbons (PAH) by HPLC. This evaluation shows that, in general, soils from sites in Charqueadas, demonstrated a genotoxic effect associated with increased oxidative stress, inorganic and PAH content. These results demonstrate that the coal pyrite tailings from Charqueadas are potentially genotoxic and that H. aspersa is confirmed to be a sensitive instrument for risk assessment of environmental pollution.

Assuntos

RESUMO

The ability of organisms to perform at different temperatures could be described by a continuous nonlinear reaction norm (i.e., thermal performance curve, TPC), in which the phenotypic trait value varies as a function of temperature. Almost any shift in the parameters of this performance curve could highlight the direct effect of temperature on organism fitness, providing a powerful framework for testing thermal adaptation hypotheses. Inter-and intraspecific differences in this performance curve are also reflected in thermal tolerances limits (e.g., critical and lethal limits), influencing the biogeographic patterns of species' distribution. Within this context, here we investigated the intraspecific variation in thermal sensitivities and thermal tolerances in three populations of the invasive snail Cornu aspersum across a geographical gradient, characterized by different climatic conditions. Thus, we examined population differentiation in the TPCs, thermal-coma recovery times, expression of heat-shock proteins and standard metabolic rate (i.e., energetic costs of physiological differentiation). We tested two competing hypotheses regarding thermal adaptation (the "hotter is better" and the generalist-specialist trade-offs). Our results show that the differences in thermal sensitivity among populations of C. aspersum follow a latitudinal pattern, which is likely the result of a combination of thermodynamic constraints ("hotter is better") and thermal adaptations to their local environments (generalist-specialist trade-offs). This finding is also consistent with some thermal tolerance indices such as the Heat-Shock Protein Response and the recovery time from chill-coma. However, mixed responses in the evaluated traits suggest that thermal adaptation in this species is not complete, as we were not able to detect any differences in neither energetic costs of physiological differentiation among populations, nor in the heat-coma recovery.

Assuntos

RESUMO

The strong dependence of metabolic rates on body mass has attracted the interest of ecological physiologists, as it has important implications to many aspects of biology including species variations in body size, the evolution of life history, and the structure and function of biological communities. The great diversity of observed scaling exponents has led some authors to conclude that there is no single universal scaling exponent, but instead it ranges from 2/3 to 1. Most of the telling evidence against the universality of power scaling exponents comes from ontogenetic changes. Nevertheless, there could be other sources of phenotypic variation that influence this allometric relationship at least at the intraspecific level. In order to explore the general concept of the metabolic scaling in terrestrial molluscs we tested the role of several biological and methodological sources of variation on the empirically estimated scaling exponent. Specifically, we measured a proxy of metabolic rate (CO(2) production) in 421 individuals, during three generations, in three different populations. Additionally, we measured this scaling relationship in 208 individuals at five developmental stages. Our results suggest that the metabolic scaling exponent at the intraspecific level does not have a single stationary value, but instead it shows some degree of variation across geographic distribution, transgenerational change and ontogenetic stages. The major differences in the metabolic scaling exponent that we found were at different developmental stages of snails, because ontogeny involves increases in size at different rates, which in turn, generate differential energy demands.

Assuntos

RESUMO

The invasive Pomacea canaliculata estivates during periods of drought and should cope with harmful effects of reoxygenation during arousal. We studied thiobarbituric acid reactive substances (TBARS), enzymatic (superoxide dismutase, SOD and catalase, CAT) and non-enzymatic antioxidants (uric acid and reduced glutathione), and heat shock protein expression (Hsc70, Hsp70 and Hsp90) in (1) active control snails, (2) snails after 45 days of estivation, and (3) aroused snails 20 min and (4) 24 h after water exposure, in midgut gland, kidney and foot. Both kidney and foot (but not the midgut gland) showed a TBARS increase during estivation and a decrease after arousal. Tissue SOD and CAT did not change in any experimental groups. Uric acid increased during estivation in all tissues, and it decreased after arousal in the kidney. Allantoin, the oxidation product of uric acid, remained constant in the midgut gland but it decreased in the kidney until 20 min after arousal; however, allantoin levels rose in both kidney and foot 24 h after arousal. Reduced glutathione decreased during estivation and arousal, in both midgut gland and kidney, and it remained constant in the foot. Hsc70 and Hsp70 kidney levels were stable during the activity-estivation cycle and Hsp90 expression decreases during estivation and recovers in the early arousal. In foot, the expression of Hsp70 and Hsp90 was high during activity and estivation periods and disminished after arousal. Results indicate that a panoply of antioxidant and molecular chaperone defences may be involved during the activity-estivation cycle in this freshwater gastropod.

Assuntos

RESUMO

A mastite bovina apresenta alta prevalência nos rebanhos leiteiros e a antibioticoterapia é o procedimento mais utilizado no tratamento da mesma. O Staphylococcus aureus, agente etiológico mais frequentemente isolado em casos de mastite, tem demonstrado em diversos estudos aumento crescente no padrão de resistência aos antimicrobianos. O desenvolvimento de bactérias resistentes e a presença de resíduos de antimicrobianos no leite estimulam o desenvolvimento de novos tratamentos que solucionem estes problemas. O muco dos moluscos Achatina fulica é composto por uma glicoproteína, denominada achacin, com atividade antimicrobiana sobre bactérias Gram positivas. Sendo assim, os objetivos deste estudo foram avaliar a atividade antimicrobiana in vitro do muco de A. fulica sobre S. aureus, bem como determinar e avaliar a concentração inibitória mínima (CIM) do muco de A. fulica purificado sobre S. aureus ATCC 25923 e isolados de S. aureus provenientes de infecções intramamárias bovina. O muco foi purificado mediante cromatografia líquida de alta eficiência e a fração com atividade antimicrobiana foi submetida à quantificação protéica e microdiluição em caldo. A CIM do muco purificado determinada para a cepa ATCC 25923 correspondeu a 50 µg/mL e para os isolados de S. aureus, variou entre 12,5 e 100 µg/mL. Sendo que destes, dois isolados (6,7 %) apresentaram CIM de 12,5 µg/mL, três (10 %) CIM de 25µg/mL, vinte e três (76,6 %) CIM de 50 µg/mL e dois (6,7 %) apresentaram CIM de 100 µg/mL. A CIM50 para os isolados correspondeu a 50 µg/mL e a CIM90 a 100 µg/mL. No presente estudo observou-se que o muco purificado apresentou atividade antimicrobiana com ação bactericida. Estes resultados proporcionam perspectivas para a compreensão e otimização de protocolos microbiológicos deste potencial biofármaco com a finalidade de empregá-lo futuramente na terapêutica veterinária para o controle de infecções intramamárias causadas por S. aureus

The bovine mastitis is highly prevalent in dairy herds and antibiotic therapy is the procedure most commonly used to treat it. Staphylococcus aureus is the most frequently isolated etiologic agent in cases of mastitis and it has been shown in several studies the pattern of increasing antimicrobial resistance. Due to the development of resistant bacterias and the presence of antimicrobial residues in the milk the development of new treatments to solve those problems are required. The mucus of the molluscs Achatina fulica contains a glycoprotein called achacin that presents antimicrobial activity against Gram positive bacteria. The aim of this study was the evaluation of the in vitro antimicrobial activity of the A. fulica mucus of on S. aureus, as well the determination of the minimum inhibitory concentration (MIC) of A. fulica mucus purified on S. aureus ATCC 25923 and isolates of S. aureus from bovine intramammary infections. The mucus was purified by high performance liquid chromatography. The protein content in portion presenting the was quantified and microdiluted. The MIC determined for the purified mucus strain ATCC 25923 was 50 µg/mL and for the isolates of S. aureus ranged between 12,5 and 100 µg/mL. Among these samples, two isolates (6,7 %) showed MIC of 12,5 µg/mL, three (10 %) of MIC 25 µg/mL, twenty-three (76,6 %) MIC of 50 µg/mL and two (6,7 %) had an MIC of 100 µg/mL. The MIC50 for isolates was 50 µg/mL and MIC90 to100 µg/mL. It was found that the purified mucus showed bactericidal activity. The results showed in the present work improved the understanding and optimization of the biopharmaceutical microbiological potential that could be applied in new protocols in future veterinary therapy for the control of intramammary infections caused by S. aureus

Assuntos

RESUMO

Achatina fulica é uma espécie nativa da África, introduzida no Brasil com fins alimentícios, como o “escargot” (Helix spp.). O caramujo gigante africano é uma espécie amplamente distribuída no Brasil e comumente relatada como hospedeiro intermediário dos nematóides Angiostrongylus cantonensis, A. costaricensis e Aelurostrongylus abstrusus. Achatina fulica é um animal com alto potencial produtivo mas também zoonótico que não têm estudos em nossa região, relacionados a sua produção e sua atuação como hospedeiro intermediário de zoonoses. Foram analisadas amostras de nematódeos obtidos dos caramujos, no período de Janeiro de 2010 a Julho de 2011. Após a extração de DNA, através do método do Fenol-Clorofórmio, realizou-se o diagnóstico das amostras através da técnica de Reação em Cadeia da Polimerase, utilizando pares de primers AabFor (forward 5`GTA ACA ACG ATA TTG GTA CTA TG-3`) e AabRev (reverse 5`GAA CTC CTT CAC GTG CTA CTC G-3`) específicos para Aelurostrongylus abstrusus. O presente estudo teve como objetivo relatar a ocorrência deste molusco em nossa região e identificar Aelurostrongylus abstrusus provenientes de Achatina fulica procedentes de Araguaina, Tocantins

Assuntos

RESUMO

O comportamento de moluscos terrestres é pouco estudado, apesar de representar uma ferramenta importante para a conservação ou controle desses animais. Desse modo, objetivou-se descrever o etograma básico de Bulimulus tenuissimus, verificar a ocorrência de comportamento agregativo e preferência por sítio de repouso. Para descrição do etograma, observaram-se grupos de 15 moluscos durante 24 horas, através do método de varredura a intervalos de 10 minutos. Para verificação do comportamento agregativo, outros 50 animais foram divididos em grupos de 10 e acondicionados em terrários plásticos previamente divididos em quadrantes. A agregação foi estabelecida pelo número de moluscos/quadrante, e a preferência por sítio de repouso, pelo número de moluscos em posições pré-determinadas. Confirmou-se o hábito noturno da espécie, sendo os atos comportamentais explorar e alimentar-se os mais frequentes. Não se observou a existência de comportamento agregativo, e a parede do terrário foi o sítio de repouso mais utilizado pelos moluscos.

The behavior of land snails is few studied, although it represents an important tool for conservation or control of such animals. Thus, it was aimed to describe the basic ethogram of Bulimulus tenuissimus, verify occurrence of aggregative behavior and preference for site rest. To describe the ethogram, groups of 15 snails was observed for 24 hours by the scanning method at intervals of 10 minutes. To verify the aggregative behavior, other 50 animals were divided into groups of 10 animals and kept in plastic terrariums previously divided into quarters. Aggregation was established by the number of snails/quadrant and the preference for site rest, by the number of snails in pre-determined positions. It was confirmed the nocturnal habits of this species, and the most frequents acts behavioral were explore and food. It wasn't observed aggregative behavior and the terrarium's wall was the site rest most often used by snails.

Assuntos

RESUMO

O comportamento de moluscos terrestres é pouco estudado, apesar de representar uma ferramenta importante para a conservação ou controle desses animais. Desse modo, objetivou-se descrever o etograma básico de Bulimulus tenuissimus, verificar a ocorrência de comportamento agregativo e preferência por sítio de repouso. Para descrição do etograma, observaram-se grupos de 15 moluscos durante 24 horas, através do método de varredura a intervalos de 10 minutos. Para verificação do comportamento agregativo, outros 50 animais foram divididos em grupos de 10 e acondicionados em terrários plásticos previamente divididos em quadrantes. A agregação foi estabelecida pelo número de moluscos/quadrante, e a preferência por sítio de repouso, pelo número de moluscos em posições pré-determinadas. Confirmou-se o hábito noturno da espécie, sendo os atos comportamentais explorar e alimentar-se os mais frequentes. Não se observou a existência de comportamento agregativo, e a parede do terrário foi o sítio de repouso mais utilizado pelos moluscos.(AU)

The behavior of land snails is few studied, although it represents an important tool for conservation or control of such animals. Thus, it was aimed to describe the basic ethogram of Bulimulus tenuissimus, verify occurrence of aggregative behavior and preference for site rest. To describe the ethogram, groups of 15 snails was observed for 24 hours by the scanning method at intervals of 10 minutes. To verify the aggregative behavior, other 50 animals were divided into groups of 10 animals and kept in plastic terrariums previously divided into quarters. Aggregation was established by the number of snails/quadrant and the preference for site rest, by the number of snails in pre-determined positions. It was confirmed the nocturnal habits of this species, and the most frequents acts behavioral were explore and food. It wasn't observed aggregative behavior and the terrarium's wall was the site rest most often used by snails.(AU)

Assuntos

RESUMO

The effect of extremely low frequency magnetic fields (50 Hz, 0.5 mT) - ELF-MF, on phosphate metabolism has been studied in the isolated ganglions of the garden snail Helix pomatia, after 7 and 16 days of snail exposure to ELF-MF. The influence of ELF-MF on the level of phosphate compounds and intracellular pH was monitored by ³¹P NMR spectroscopy. Furthermore, the activity of enzymes involved in phosphate turnover, total ATPases, Na+/K+-ATPase and acid phosphatase has been measured. The exposure of snails to the ELF-MF for the period of 7 days shifted intracellular pH toward more alkaline conditions, and increased the activity of investigated enzymes. Prolonged exposure to the ELF-MF for the period of 16 days caused a decrease of PCr and ATP levels and decreased enzyme activity, compared to the 7-day treatment group. Our results can be explained in terms of: 1. increase in phosphate turnover by exposure to the ELF-MF for the period of 7 days, and 2. adaptation of phosphate metabolism in the nervous system of snails to prolonged ELF-MF exposure.

Assuntos

RESUMO

Estudou-se o efeito da endogamia sobre as características sobrevivência (intervalos de 0-30; 30-60; 60-90 e 90-120 dias) e longevidade do escargot da espécie Helix aspersa em três gerações consecutivas de acasalamentos entre irmãos perfeitos. Os animais foram criados em laboratório com temperatura entre 20 e 25ºC e umidade relativa entre 70 a 90 por cento. O menor percentual de sobrevivência ocorreu no primeiro intervalo, mas, com o aumento da endogamia, observou-se diminuição na sobrevivência nos quatro intervalos testados. A longevidade média foi de 314 e 306 dias para as gerações um e três, respectivamente, não tendo sido observados animais em hibernação. O estudo de simulação para o caráter sobrevivência, em função do coeficiente de endogamia, indicou que se deve iniciar uma criação com, pelo menos, 100 reprodutores não aparentados.

The effect of inbreeding on longevity and viability (intervals of 0-30, 30-60, 60-90, and 90-120 days of birth) in three consecutive generations of full sibs of escargot Helix aspersa raised under laboratory conditions (20-25ºC temperature; 70-90 percent relative humidity) was studied. Inbreeding effects decreased the viability for all the studied intervals. The longevity means were 314 and 306 days, respectively to the first and third generations. Hibernating animals were not observed. Population size of at least 100 non-related mating escargots replaced after 10 generations to avoid inbreeding effect is recommended.

Assuntos

RESUMO

Estudou-se o efeito da endogamia sobre as características sobrevivência (intervalos de 0-30; 30-60; 60-90 e 90-120 dias) e longevidade do escargot da espécie Helix aspersa em três gerações consecutivas de acasalamentos entre irmãos perfeitos. Os animais foram criados em laboratório com temperatura entre 20 e 25ºC e umidade relativa entre 70 a 90 por cento. O menor percentual de sobrevivência ocorreu no primeiro intervalo, mas, com o aumento da endogamia, observou-se diminuição na sobrevivência nos quatro intervalos testados. A longevidade média foi de 314 e 306 dias para as gerações um e três, respectivamente, não tendo sido observados animais em hibernação. O estudo de simulação para o caráter sobrevivência, em função do coeficiente de endogamia, indicou que se deve iniciar uma criação com, pelo menos, 100 reprodutores não aparentados.(AU)

The effect of inbreeding on longevity and viability (intervals of 0-30, 30-60, 60-90, and 90-120 days of birth) in three consecutive generations of full sibs of escargot Helix aspersa raised under laboratory conditions (20-25ºC temperature; 70-90 percent relative humidity) was studied. Inbreeding effects decreased the viability for all the studied intervals. The longevity means were 314 and 306 days, respectively to the first and third generations. Hibernating animals were not observed. Population size of at least 100 non-related mating escargots replaced after 10 generations to avoid inbreeding effect is recommended.(AU)

Assuntos

RESUMO

El objetivo del estudio fue comparar la flora bacteriana de intestino y hepatopáncreas del caracol Helix aspersa Müller criados en dos sistemas de producción: intensivo y extensivo. Se colectaron 30 caracoles adultos aparentemente sanos por cada sistema de producción, en seis criaderos ubicados en la provincia de Lima. Se tomó muestras de mucosa intestinal y parénquima del hepatopáncreas de cada individuo, empleando protocolos de aislamientos establecidos para bacterias aerobias y aerobias facultativas. Se aisló bacterias de 15 géneros: Escherichia, Citrobacter, Klebsiella, Enterobacter, Serratia, Hafnia, Proteus, Providencia, Aeromonas, Staphylococcus, Streptococcus, Enterococcus, Micrococcus, Pseudomonas, Acinetobacter; y bacilos gramnegativos no fermentadores (BNF). Se obtuvo 193 cepas en las muestras de caracoles del sistema extensivo, donde el género Escherichia fue el de mayor frecuencia (17.1%, 33/193); mientras que en caracoles del sistema intensivo se aisló 183 cepas, donde el género Klebsiella fue el de mayor frecuencia (17.5%, 32/183). Por otro lado, el género más frecuentemente aislado en intestino y hepatopáncreas fue Klebsiella (13.6%, 25/184 y 17.2%, 33/192, respectivamente). Bacterias de los géneros Providencia y Micrococcus solo se encontraron en el hepatopáncreas. Hubo diferencias estadísticas en la frecuencia de algunas bacterias aisladas dentro de cada tipo de muestra por efecto del sistema de crianza.

The objective of this study was to compare the bacterial flora present in the intestine and hepatopancreas of land snails (Helix aspersa Müller) under intensive and extensive breeding systems. Thirty healthy adult snails per production system were collected from six farms located in the province of Lima. Samples from intestinal mucosa and the hepatopancreas were examined from each animal using protocols of microbiological isolation established for aerobic and facultative aerobic bacteria. Bacteria of 15 genuses were isolated: Escherichia, Citrobacter, Klebsiella, Enterobacter, Serratia, Hafnia, Proteus, Providencia, Aeromonas, Staphylococcus, Streptococcus, Enterococcus, Micrococcus, Pseudomonas, Acinetobacter; and non-fermentative gram-negative bacillus (BNF). It was obtained 193 strains from samples of the extensive production system, where bacteria of the Escherichi genus were predominant (17.1%, 33/193); and 183 strains were isolated from samples in the intensive production system where the Klebsiella genus was the most frequent (17.5%, 32/183). Also, the Klebsiella was the most frequent isolated genus in both the intestine and the hepatopancreas (13.6%, 25/184, and 17.2%, 33/192 respectively). The Providencia and Micrococcus genuses were only isolated from the hepatopancreas. Statistical differences on the frequency of bacteria isolated between production systems were found.

Assuntos

RESUMO

Coal mining is an activity with a high potential for environmental pollution. Coal has been described as the most significant pollutant of all the fossil fuels, containing a heterogeneous mixture. Many elements present in coal byproducts as well as coal tailings are rich in potentially toxic and genotoxic metals, which ultimately lead to profound changes in cells, tissues, populations, and ecosystems. The purpose of this study was to assess the genotoxic potential of the mineral coal tailings using the land snail Helix aspersa. Animals were divided in three groups, clustered in plexiglass cages: control (animals fed with organic lettuce), coal tailings (animals living in a layer of pyrite tailings and fed with organic lettuce), and mine lettuce (animals fed with lettuce grown in an area located in a deposit of coal tailings). The hemolymph was collected at different exposure times (24 h, 48 h, 72 h, 96 h, 1 week, 2 weeks, 3 weeks, and 1 month) for comet assay analyses. Results showed that the animals of the coal tailings and mine lettuce groups presented higher levels of DNA damage in relation to the control group at all exposure times, but with a peak of DNA damage in 48 h and 96 h. These results demonstrate that the coal pyrite tailings are potentially genotoxic and that H. aspersa has proven to be a sensitive instrument for a better risk assessment of environmental pollution.

Assuntos

RESUMO

The effect of extremely low frequency magnetic felds (50 Hz, 0.5 mT) - ELF-MF, on phosphate metabolism has been studied in the isolated ganglions of the garden snail Helix pomatia, after 7 and 16 days of snail exposure to ELF-MF. The infuence of ELF-MF on the level of phosphate compounds and intracellular pH was monitored by 31P NMR spectroscopy. Furthermore, the activity of enzymes involved in phosphate turnover, total ATPases, Na+/K+-ATPase and acid phosphatase has been measured. The exposure of snails to the ELF-MF for the period of 7 days shifted intracellular pH toward more alkaline conditions, and increased the activity of investigated enzymes. Prolonged exposure to the ELF-MF for the period of 16 days caused a decrease of PCr and ATP levels and decreased enzyme activity, compared to the 7-day treatment group. Our results can be explained in terms of: 1. increase in phosphate turnover by exposure to the ELF-MF for the period of 7 days, and 2. adaptation of phosphate metabolism in the nervous system of snails to prolonged ELF-MF exposure.

Assuntos

RESUMO

Achatina fulica, ou caramujo africano, foi introduzido no Brasil em meados da década de 1980 para ser comercializado como escargot. No entanto, em virtude da baixa demanda do mercado consumidor, os criadores desativaram seus plantéis, gerando fuga ou liberação intencional de exemplares que, livres no ambiente, espalharam-se repidamente por quase todo país (24 estados mais o Distrito Federal). As densas populações do caramujo africano causam uma série de problemas, como a destruição de hortas e jardins, competição com a fauna nativa, além de poderem transmitir zoonoses como a angiostrongilose abdominal e a meningite eosinofílica. A exemplo do que ocorre em outras partes do país, o Município de Barra do Piraí, Estado do Rio de Janeiro, encontra-se também infestado. Visando contribuir para o enfrentamento dos danos causados por essa espécie, o presente estudo objetivou: pesquisar a helmintofauna de populações de A. fulica em alguns bairros de Barra do Piraí quanto à presença de larvas de helmintos de importância médico-veterinária; analisar as percepções relacionadas ao caramujo africano entre estudantes do Ensino Fundamental de uma escola pública estadual no referido município. A pesquisa, de abordagem qualitativa, foi realizada em duas etapas: 1) coleta de exemplares de A. fulica nos bairros Arthur Cataldi, Dorândia, Química, Boca do Mato e São João no período de fevereiro de 2008 a novembro de 2009, os quais foram analisados no Laboratório de Malacologia do Instituto Oswaldo Cruz/Fiocruz (Referência Nacional em Malacologia); 2) aplicação de 82 questionários e a realização de quatro grupos focais com alunos do Ensino Fundamental, além de observações de campo. Os resultados obtidos ao longo do trabalho comprovam que há uma infestação de caramujos africanos no município. A pesquisa da helmitofauna revelou que caramujos provenientes de dois dos cinco bairros analisados quais sejam, Química e Dorândia, apresentaram o nematódeo Angiostrongylus cantonensis causador da meningite eosinofílica no homem. Além disso, também foram encontrados no município os nematódeos Strongyluris-like e Aelurostrongylus abstrusus que causam doenças em animais. Os dados referentes ao estudo das percepções revelaram que os alunos identificaram a presença do caramujo africano no contexto no qual estão inseridos, e embora a maioria acredite que esse animal possa causar doenças, apenas uma minoria afirma conhecer pessoas que tiveram problemas com o caramujo. Os dados igualmente apontam para divergências entre a visão dos alunos e o conhecimento científico sobre as formas de controle de A. fulica e os tipos de agravos, em função do contato ou ingestão dessa espécie. Os laudos referentes ao exame dos moluscos e as recomendações aos órgãos municipais sobre o controle e monitoramento A. fulica já foram encaminhados à secretaria de saúde do município para que sejam tomadas as devidas providências. Da mesma forma o trabalho será disponibilizado aos professores da escola que participou desta pesquisa para que suas contribuições possam auxiliar na prática docente. Espera-se que os resultados deste trabalho possam subsidiar o desenvolvimento de ações de controle e monitoramento de A. fulica no município, bem como ações educativas em conexões formais e não formais de ensino para trabalhar com essa temática, adequadas à realidade da comunidade.

Assuntos

RESUMO

The photoprotective effect of the methanolic extracts of three Antarctic plant species - Deschampsia antarctica Desv., Colobanthus quitensis (Kunth) Bartl., and Polytrichum juniperinum Hedw. against UV-induced DNA damage was investigated in hamster lung fibroblasts (V79 cells) and in a biomonitor organism Helix aspersas, using comet assay. The protective, mutagenic, and antimutagenic profiles of these extracts were also evaluated using haploid strains of the simple eukaryote Saccharomyces cerevisiae, and antioxidant activity were investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, as well as the hypoxanthine/xanthine oxidase assay. At the concentration range employed, the extracts were not cytotoxic or mutagenic to S. cerevisiae. In addition, the treatment with these extracts enhanced survival, and decreased induced reverse, frameshift, and forward mutations in a dose-response manner in all UVC doses employed. The plants extracts did not generate DNA strand breaks in V79 cells, and the treatment significantly decreased DNA damage induced by UVC. Extracts significantly decreased UVC-induced lipid peroxidation in V79 cells, showing a clear antioxidant property. Moreover, results of comet assay in V79 cells, employing Fpg, Endo III, and Endo V enzymes, demonstrated significant reduction of UVC-induced DNA damage after pre-incubation with these extracts. The treatment with all tested extracts were much less efficient against UVC-induced cytotoxicity in the yeast strain defective in photolyase as compared to the wild type strain, suggesting that this DNA repair pathway is stimulated by substances present in the extracts. All extracts showed a significant inhibitory effect in the hypoxanthine/xanthine oxidase assay, and they had the ability to scavenge DPPH. In H. aspersas, the treatment was able to protect against UVC-induced damage. In conclusion, D. antarctica, C. quitensis, and P. juniperinum extracts present photoprotective properties, which can be attributed to molecules, such as flavonoids and carotenoids, which act as UV-absorbing molecules and as antioxidants, as well as stimulate DNA-repair processes.

Assuntos

RESUMO

The purpose of this study was to biomonitor metropolitan areas of Porto Alegre (Brazil) for PAHs associated with atmospheric particles and check their effects on the DNA of the land mollusk Helix aspersa. The sampling sites are located in an urban area with heavy traffic: (i) Canoas, (ii) Sapucaia do Sul, and (iii) FIERGS/Porto Alegre. The samples were collected during a continuous period of 24 hours during 15 days using Stacked Filter Units (SFU) on polycarbonate filters (two separated size fractions: PM(10-2.5) and PM(< 2.5)). The concentrations of 16 major PAHs were determined according to EPA. Comet assay on H. aspersa hemolymph cells was chosen for genotoxicity evaluation. This evaluation shows that, in general, the smaller PM-size fractions (PM(< 2.5)) have the highest genotoxicity and contain higher concentrations of extractable organic matter. In addition, associations between chemical characteristics and PM carcinogenicity tend to be stronger for the smaller PM-size fractions.

Assuntos