Márcia Cristina Freitas da Silva

Population Dynamics of the River Prawn, Macrobrachium Amazonicum (Heller, 1862) (Decapoda, Palaemonidae) on Combu Island (Amazon Estuary)

[This study estimates reproductive parameters (length at first maturity, reproduction period, and fecundity), mortality, and maximum sustainable yield for Macrobrachium amazonicum on Combu Island (Amazon estuary). Samples were taken monthly between March 2003 and February 2004. Ovigerous females were recorded throughout the year, with reproductive peaks in the middle of the flood period (March), in the low water period (September), and the peak dry period (December) of the Guama River. The size at which 50% of the females were mature was 60.8 mm TL. Absolute fecundity varied between 40 and 3375 eggs per female. The exploitation rate for maximum sustainable yield (E MSY ) for males was lower than that for females. For both sexes, E MSY was below the exploitation rates (E). The present study demonstrates the need for management of the prawn fishery on the islands in the Amazon estuary, such as establishing a minimum commercial size. Este estudo tem o objetivo de estimar os parâmetros reprodutivos (tamanho de primeira maturidade, periodo reprodutivo e fecundidade), mortalidade e rendimento maximo sustentavel do Macrobrachium amazonicum da Ilha do Combu (Estuario Amazonico). As amostras foram coletadas mensalmente, entre marco de 2003 e fevereiro de 2004. Femeas ovigeras foram registradas ao longo de todo ano, com picos reprodutivos no meio da enchente (marco), vazante (setembro) e pico de minima vazao (dezembro) no Rio Guama. O tamanho na qual 50% das femeas estao maduras e de 60,8 mm de comprimento total. Fecundidade absoluta variou entre 40 e 3375 ovos por femea. A taxa de exploracao para a obtencao do rendimento maximo sustentavel (E RMY ) para machos foi inferior ao obtido para as femeas. Para ambos sexos E RMY foi abaixo das taxas de explotacao atuais (E). O presente estudo demonstra a necessidade do manejo da pesca de camarao nas ilhas do estuario Amazonico, como por exemplo o estabelecimento de tamanho minimo de comercializacao. , This study estimates reproductive parameters (length at first maturity, reproduction period, and fecundity), mortality, and maximum sustainable yield for Macrobrachium amazonicum on Combu Island (Amazon estuary). Samples were taken monthly between March 2003 and February 2004. Ovigerous females were recorded throughout the year, with reproductive peaks in the middle of the flood period (March), in the low water period (September), and the peak dry period (December) of the Guama River. The size at which 50% of the females were mature was 60.8 mm TL. Absolute fecundity varied between 40 and 3375 eggs per female. The exploitation rate for maximum sustainable yield (E MSY ) for males was lower than that for females. For both sexes, E MSY was below the exploitation rates (E). The present study demonstrates the need for management of the prawn fishery on the islands in the Amazon estuary, such as establishing a minimum commercial size. Este estudo tem o objetivo de estimar os parâmetros reprodutivos (tamanho de primeira maturidade, periodo reprodutivo e fecundidade), mortalidade e rendimento maximo sustentavel do Macrobrachium amazonicum da Ilha do Combu (Estuario Amazonico). As amostras foram coletadas mensalmente, entre marco de 2003 e fevereiro de 2004. Femeas ovigeras foram registradas ao longo de todo ano, com picos reprodutivos no meio da enchente (marco), vazante (setembro) e pico de minima vazao (dezembro) no Rio Guama. O tamanho na qual 50% das femeas estao maduras e de 60,8 mm de comprimento total. Fecundidade absoluta variou entre 40 e 3375 ovos por femea. A taxa de exploracao para a obtencao do rendimento maximo sustentavel (E RMY ) para machos foi inferior ao obtido para as femeas. Para ambos sexos E RMY foi abaixo das taxas de explotacao atuais (E). O presente estudo demonstra a necessidade do manejo da pesca de camarao nas ilhas do estuario Amazonico, como por exemplo o estabelecimento de tamanho minimo de comercializacao. ]

Evaluation of the Effects of Chronic Intoxication with Inorganic Mercury on Memory and Motor Control in Rats

The aims of this study were to evaluate whether chronic intoxication with mercury chloride (HgCl2), in a low concentration over a long time, can be deposited in the central nervous tissue and to determine if this exposure induces motor and cognitive impairments. Twenty animals were intoxicated for 45 days at a dose of 0.375 mg/kg/day. After this period, the animals underwent a battery of behavioral tests, in a sequence of open field, social recognition, elevated T maze and rotarod tests. They were then sacrificed, their brains collected and the motor cortex and hippocampus dissected for quantification of mercury deposited. This study demonstrates that long-term chronic HgCl2 intoxication in rats promotes functional damage. Exposure to HgCl2 induced anxiety-related responses, short- and long-term memory impairments and motor deficits. Additionally, HgCl2 accumulated in both the hippocampus and cortex of the brain with a higher affinity for the cortex.

Oxidative Biochemistry Disbalance and Changes on Proteomic Profile in Salivary Glands of Rats Induced by Chronic Exposure to Methylmercury

Methylmercury (MeHg) is one of the most toxic mercury species, which can cause many systemic damages, but little is known about its effect in the salivary glands. This study aimed to analyze the mercury levels, oxidative stress, and proteomic profile in parotid, submandibular, and sublingual salivary glands of rats, after chronic MeHg intoxication. Two groups of twenty male Wistar rats (90 days of age) were used on the experiment. MeHg group was intoxicated by intragastric gavage with MeHg at a dose of 0.04 mg/kg/day for 60 days, while the control group received only oil. After the period of intoxication, the glands were collected for evaluation of total mercury levels, proteomic profile, and oxidative balance by analyzing the antioxidant capacity against peroxyl radicals (ACAP), lipid peroxidation (LPO), and nitrite levels. Our results have showed that mercury levels were significant in all three glands compared to the respective control. It also showed lower levels of ACAP, as well as higher LPO and nitrite levels. The proteomic profile presented impairments on structural components of cytoskeleton, metabolic pathways, and oxidative biochemistry. Thus, the exposure to MeHg was able to generate oxidative stress that could be associated with changes in the proteomic profile of salivary glands.

Physical, Chemical, and Immunohistochemical Investigation of the Damage to Salivary Glands in a Model of Intoxication with Aluminium Citrate

Aluminum absorption leads to deposits in several tissues. In this study, we have investigated, to our knowledge for the first time, aluminum deposition in the salivary glands in addition to the resultant cellular changes in the parotid and submandibular salivary glands in a model of chronic intoxication with aluminum citrate in rats. Aluminum deposits were observed in the parotid and submandibular glands. Immunohistochemical evaluation of cytokeratin-18 revealed a decreased expression in the parotid gland with no changes in the submandibular gland. A decreased expression of α-smooth muscle actin was observed in the myoepithelial cells of both glands. The expression of metallothionein I and II (MT-I/II), a group of metal-binding proteins, which are useful indicators for detecting physiological responses to metal exposure, was higher in both glands. In conclusion, we have shown that at a certain time and quantity of dosage, aluminum citrate promotes aluminum deposition in the parotid and submandibular glands, leads to an increased expression of MT-I/II in both the glands, damages the cytoskeleton of the myoepithelial cells in both glands, and damages the cytoskeleton of the acinar/ductal cells of the parotid glands, with the submandibular glands showing resistance to the toxicity of the latter.

Concentração de mercúrio total (Hg-T) em peixes comercializados em diferentes períodos sazonais no Mercado do Ver-o-Peso, Belém, Estado do Pará, Brasil

El objetivo de este trabajo fue el de determinar la concentracion de mercurio total (Hg-T) en peces comercializados en el Mercado de Ver-o-Peso en Belem, Estado de Para, Brasil. Las especies de peces seleccionadas para el estudio fueron Brachyplatystoma rousseauxii, Brachyplatystoma filamentosum y Schizodon fasciatum. Se adquirieron diez ejemplares de cada especie en mayo de 2011 (periodo menos lluvioso) y noviembre de 2012 ( periodo mas lluvioso). Los analisis de Hg-T se realizaron por intermedio de un espectrofotometro de absorcion atomica Hg201, en el Laboratorio de Toxicologia Humana y Ambiental del Nucleo de Medicina Tropical de la Universidad Federal do Para. Los promedios obtenidos en la primera y la segunda colecta de B. rousseauxii fueron de 0,45 µg/g y 0,09 µg/g de Hg-T, respectivamente. Entre las muestras de B. filamentosum, el promedio obtenido fue de 0,31 µg/g y 0,30 µg/g. En los ejemplares de S. fasciatum, solo en el primer periodo se observo una concentracion que correspondio a 0,01 µg/g. Con relacion a la asociacion entre la concentracion del Hg-T y el indice de estado nutricional de las especies, solamente en las muestras de B. rousseauxii fueron halladas correlaciones positivas moderadas (r = 0,6, p > 0,05 referentes a los dos periodos colectados), en las demas no se observaron asociaciones. Aunque ninguna de las especies haya alcanzado valores superiores a lo preconizado por la Agencia Nacional de Vigilancia Sanitaria, es importante considerar el efecto acumulativo del mercurio en el organismo. La ausencia o moderada correlacion encontradas sugieren la necesidad de nuevos estudios para mejor comprension delindice nutricional del pescado y de la contaminacion por mercurio

Exposure to Inorganic Mercury Causes Oxidative Stress, Cell Death, and Functional Deficits in the Motor Cortex

Mercury is a toxic metal that can be found in the environment in three different forms – elemental, organic and inorganic. Inorganic mercury has a lower liposolubility, which results in a lower organism absorption and reduced passage through the blood–brain barrier. For this reason, exposure models that use inorganic mercury in rats in order to evaluate its effects on the central nervous system are rare, especially in adult subjects. This study investigated if a chronic exposure to low doses of mercury chloride (HgCl2), an inorganic form of mercury, is capable of promoting motor alterations and neurodegenerative in the motor cortex of adult rats. Forty animals were exposed to a dose of 0.375 mg/kg/day, for 45 days. They were then submitted to motor evaluation and euthanized to collect the motor cortex. Measurement of mercury deposited in the brain parenchyma, evaluation of oxidative balance, quantification of cellular cytotoxicity and apoptosis and density of mature neurons and astrocytes of the motor cortex were performed. It was observed that chronic exposure to inorganic mercury caused a decrease in balance and fine motor coordination, formation of mercury deposits and oxidative stress verified by the increase of lipoperoxidation and nitrite concentration and a decrease of the total antioxidant capacity. In addition, we found that this model of exposure to inorganic mercury caused cell death by cytotoxicity and induction of apoptosis with a decreased number of neurons and astrocytes in the motor cortex. Our results provide evidence that exposure to inorganic mercury in low doses, even in spite of its poor ability to cross biological barriers, is still capable of inducing motor deficits, cell death by cytotoxicity and apoptosis, and oxidative stress in the motor cortex of adult rats.

Low doses of methylmercury exposure during adulthood in rats display oxidative stress, neurodegeneration in the motor cortex and lead to impairment of motor skills

Despite the vast distribution among tissues, the central nervous system (CNS) represents the main target of methylmercury (MeHg) toxicity. However, few studies have evaluated the effects of MeHg exposure on the CNS at equivalent doses to human environmental exposure. In our study, we evaluated the motor cortex, an important area of motor control, in adult rats chronically exposed to MeHg in a concentration equivalent to those found in fish-eating populations exposed to mercury (Hg). The parameters evaluated were total Hg accumulation, oxidative stress, tissue damage, and behavioral assessment in functional actions that involved this cortical region. Our results show in exposed animals a significantly greater level of Hg in the motor cortex; increase of nitrite levels and lipid peroxidation, associated with decreased antioxidant capacity against peroxyl radicals; reduction of neuronal and astrocyte density; and poor coordination and motor learning impairment. Our data showed that chronic exposure at low doses to MeHg is capable of promoting damages to the motor cortex of adult animals, with changes in oxidative biochemistry misbalance, neurodegeneration, and motor function impairment.

Repeated Cycles of Binge-Like Ethanol Intake in Adolescent Female Rats Induce Motor Function Impairment and Oxidative Damage in Motor Cortex and Liver, but Not in Blood

Moderate ethanol consumption (MEC) is increasing among women. Alcohol exposure usually starts in adolescence and tends to continue until adulthood. We aimed to investigate MEC impacts during adolescence until young adulthood of female rats. Adolescent female Wistar rats received distilled water or ethanol (3 g/kg/day), in a 3 days on-4 days off paradigm (binge drinking) for 1 and 4 consecutive weeks. We evaluate liver and brain oxidative damage, peripheral oxidative parameters by SOD, catalase, thiol contents, and MDA, and behavioral motor function by open-field, pole, beam-walking, and rotarod tests. Our results revealed that repeated episodes of binge drinking during adolescence displayed lipid peroxidation in the liver and brain. Surprisingly, such oxidative damage was not detectable on blood. Besides, harmful histological effects were observed in the liver, associated to steatosis and loss of parenchymal architecture. In addition, ethanol intake elicited motor incoordination, bradykinesia, and reduced spontaneous exploratory behavior in female rats.

Hippocampal Dysfunction Provoked by Mercury Chloride Exposure: Evaluation of Cognitive Impairment, Oxidative Stress, Tissue Injury and Nature of Cell Death

Mercury (Hg) is a highly toxic metal, which can be found in its inorganic form in the environment. This form presents lower liposolubility and lower absorption in the body. In order to elucidate the possible toxicity of inorganic Hg in the hippocampus, we investigated the potential of low doses of mercury chloride (HgCl2) to promote hippocampal dysfunction by employing a chronic exposure model. For this, 56 rats were exposed to HgCl2 (0.375 mg/kg/day) via the oral route for 45 days. After the exposure period, the animals were submitted to the cognitive test of fear memory. The hippocampus was collected for the measurement of total Hg levels, analysis of oxidative stress, and evaluation of cytotoxicity, apoptosis, and tissue injury. It was observed that chronic exposure to inorganic Hg promotes an increase in mercury levels in this region and damage to short- and long-term memory. Furthermore, we found that this exposure model provoked oxidative stress, which led to cytotoxicity and cell death by apoptosis, affecting astrocytes and neurons in the hippocampus. Our study demonstrated that inorganic Hg, even with its low liposolubility, is able to produce deleterious effects in the central nervous system, resulting in cognitive impairment and hippocampal damage when administered for a long time at low doses in rats.

Presença de hidrocarbonetos policíclicos aromáticos em produtos alimentícios e a sua relação com o método de cocção e a natureza do alimento

Abstract Polycyclic Aromatic Hydrocarbons (PAH) can be associated with carcinogenesis in humans. These elements enter the body via the gastrointestinal tract, making the diet an important contamination route. The objective of this review was to analyze the comprehensive relationship between the formation/ingestion of these compounds and the diet. A significant association was found between the cooking method and the increase in PAH levels in foods and the formation of new compounds. The thermal source applied, food composition, type of oil, especially in the frying processes, as well as the type of treatment used before cooking, influenced the PAH content in the final product. Brazilian legislation for these compounds is not comprehensive and the need to expand national standards becomes even more evident when this issue is seen as a matter of Food Safety. Keywords: Polycyclic Aromatic Hydrocarbons; Feeding; Nutrition; Cancer. Allane Patricia Santos da Paz 1 *, Ellen Cristina Pimenta Nascimento