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Made available in DSpace on 2019-09-12T16:53:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2017 Ministério do Meio Ambiente (MMA) Ministério da Ciência, Tecnologia e Inovação (MCTI) Secretaria da Comissão Interministerial para os Recursos do Mar (SECIRM) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) The gastropod Nacella concinna is the most conspicuous macroinvertebrate of the intertidal zone of the Antarctic Peninsula and adjacent islands. Naturally high levels of copper and cadmium in coastal marine ecosystems are accumulated in N. concinna tissues. We aimed to study the effects of metal cations on N. concinna arginase in the context of possible adaptive microevolution. Gills and muscle had the highest argininolytic activity, which was concentrated in the cytosol in both tissues. Gills had the highest levels of arginase and may be involved in the systemic control of L-arginine levels. The relatively high argininolytic activity of the N. concinna muscular foot, with K-M = 25.3 +/- 3.4 mmol L-1, may be involved in the control of L-arginine levels during phosphagen breakdown. N. concinna arginases showed the following preferences for metal cations: Ni2+ > Mn2+ > Co2+ > Cu2+ in muscle and Mn2+ > Cu2+ in gills. Cu2+ activation is a unique characteristic of N. concinna arginases, as copper is a potent arginase inhibitor. Cu2+ partly neutralized N. concinna arginase inhibition by Cd2+, worked synergistically in muscle arginase activation by Co2+ and neutralized muscle arginase activation by Ni2+. Mn2+ was able to activate muscle arginase in the presence of Fe3+ and Pb2+. The selection of arginases that are activated by Cu2+ and resistant to inhibition by Cd2+ in the presence of Cu2+ over evolutionary timescales may have favored N. concinna occupation of copper- and cadmium-rich niches. (C) 2016 Elsevier Inc. All rights reserved. [de Oliveira, Mariana Feijo; Rodrigues Junior, Edson; Kawagoe Suda, Cecilia Nahomi; Vani, Gannabathula Sree; Rodrigues, Edson] Universidade de Taubaté (Unitau), Basic Biosci Inst [Donatti, Lucelia] Univ Fed Parana, Dept Cell Biol, Curitiba, Parana, Brazil [Lavrado, Helena Passeri] Univ Fed Rio de Janeiro, Dept Marine Biol, Rio De Janeiro, Brazil

Made available in DSpace on 2019-09-12T16:53:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2015 Instituto Nacional de Ciência e Tecnologia Antártico de Pesquisas Ambientais (INCT-APA) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) Physiological studies suggest that Antarctic marine organisms are adversely affected by rising global temperatures and ocean acidification and have poor prospects for survival. However, according to ecological studies, their vulnerability might be less severe than initially thought. Thus, a realistic forecast of species survival and Antarctic biodiversity should be based on studies from a variety of species under consideration of ecological factors. The limpet Nacella concinna is often found in the rocky intertidal and sublittoral zones of the Antarctic Peninsula and adjacent subantarctic islands. This review summarizes most of the available information on the biology of this limpet, one of the most conspicuous invertebrates of the intertidal zone. There is some evidence that adult N. concinna are physiologically flexible and can acclimate to 3 A degrees C. However, the requirements of the larval stage are poorly known, thus precluding realistic predictions of how elevated temperatures will affect N. concinna populations. Data on physiological performance (righting ability, tenacity and radula rasping rate) under different temperatures could provide a useful baseline for further field investigations on the effects of warming. The species could be used as model organism for investigating the biological effects of ongoing global warming on slow-growing Antarctic ectotherms. Nacella concinna might also be a better biomonitor for polycyclic aromatic hydrocarbons than other Antarctic mollusks. [Suda, Cecilia N. K.; Vani, Gannabathula S.; de Oliveira, Mariana Feijo; Rodrigues, Edson, Jr.; Rodrigues, Edson; Lavrado, Helena P.] Univ Fed Rio de Janeiro, Natl Inst Sci & Technol Antarctic Environm Res IN, Headquarters, BR-21941902 Rio De Janeiro, RJ, Brazil [Suda, Cecilia N. K.; Vani, Gannabathula S.; de Oliveira, Mariana Feijo; Rodrigues, Edson] Universidade de Taubaté (Unitau), Basic Biosci Inst, BR-12030180 Taubate, SP, Brazil [de Oliveira, Mariana Feijo; Rodrigues, Edson, Jr.] Univ Fed Parana, Dept Cell Biol, BR-81990970 Curitiba, Parana, Brazil [Lavrado, Helena P.] Univ Fed Rio de Janeiro, Dept Marine Biol, BR-21941902 Rio De Janeiro, RJ, Brazil

Made available in DSpace on 2019-09-12T16:53:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2015 Ministério do Meio Ambiente (MMA) Ministério da Ciência, Tecnologia e Inovação (MCTI) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Secretariat of the Inter-ministerial Commission for the Resources of the Sea (SeCIRM) Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) Instituto Nacional de Ciência e Tecnologia Antártico de Pesquisas Ambientais (INCT-APA) The intertidal and subtidal environments in the Antarctic Peninsula are vulnerable to pollutants, such as diesel oil, a commonly used fuel. Nacelle concinna is capable of accumulating polycyclic aromatic hydrocarbons and is a potential biomonitor of diesel oil contamination. This work investigates the interaction of diesel oil, temperature and salinity on the activity of antioxidants enzymes defense of the gills, foot muscle and digestive glands. Upregulation of superoxide dismutase occurred in the three tissues by warming. The foot muscle catalase and the gill glutathione reductase were upregulated only by diesel. The inability to upregulate catalase and glutathione S-transferase in the digestive gland, as well as the increase of lipoperoxidation, suggested that this gland is more susceptible to the deleterious effects from oxidative stress. (C) 2015 Elsevier Ltd. All rights reserved. [de Oliveira, Mariana Feijo; Rodrigues Junior, Edson; Donatti, Lucelia] Univ Fed Parana, Dept Cell Biol, BR-81530130 Curitiba, Parana, Brazil [de Oliveira, Mariana Feijo; Rodrigues Junior, Edson; Suda, Cecilia N. K.; Vani, Gannabathula S.; Rodrigues, Edson] Universidade de Taubaté (Unitau), Basic Biosci Inst, BR-12030180 Taubate, SP, Brazil [Lavrado, Helena P.] Univ Fed Rio de Janeiro, Dept Marine Biol, BR-21941902 Rio De Janeiro, RJ, Brazil

Herein we report the formation of polyelectrolyte complexes (PECs) based on type-A gelatin and gum arabic. The polysaccharides were extracted from gum exudates of Acacia mearnsii De Wild, grown in Brazil, where they are considered an agro industrial residue. Two polysaccharide fractions were obtained from crude A. mearnsii gum exudates, after successive aqueous and alkaline extractions, denoted as GNF and GNA, respectively. Molecular and functional properties differ between samples. Surface behavior of GNF and GNA are mainly associated with their composition and molecular mass distribution profile. The results were compared to a commercial gum (GAC). Targeting optimal complexation conditions, a straightforward and elegant approach was employed, that consists in determining the pKa of the macromolecules, which is intrinsically related to their molecular characteristics. Hence, the optimal condition is achieved when the concentration of positively and negatively charged species of gelatin and gum, respectively, are concomitantly maximized. This method proved to be simple and effective in predicting the best pH for obtaining PECs, corroborated by a thorough complexation study at different pHs. Our work demonstrates that the optimal complexation pH is the key parameter to obtain reproducible microcapsules with targeted features, regardless of the origin of the gum. Also, GNF and GNA showed to be promising substituents for GAC, thus extending the range of applications of acacia gum obtained in Brazil, strengthening the interest in this material.

Arginases are metalloenzymes broadly distributed in nature. These enzymes catalyze the L-arginine hydrolyses to L-ornithine and urea. The aim of the present work is to determine the tissue levels of arginase, its kinetic properties and subcellular localization. In December 2009, specimens were collected in Admiralty Bay, King George Island near the Brazilian Research Station. The argininolytic specific activity of foot muscle, gills and pool of other tissues was 87.0 ± 15.1; 9.8 ± 1.8 and 3.8 ± 1.0 mU/mg protein, respectively. Mainly localized in the cytosol, gills and muscular arginase Km values for L-arginine were 57.0 ± 10.5 and 66.2 ± 14.6 mM, respectively. High arginase levels in gills could be related to the systemic control of L-arginine concentrations, which is vital for energetic metabolism of phospho-L-arginine and of polyamines in the control of cell proliferation though the probable physiologic metal cation is Mn 2+ , some arginases are activated by Co 2+ and Ni 2+ . The muscle Nacella concinna arginases were activated by Mn 2+ and Co 2+ and inhibited by Cd 2+ whereas; gills arginase was activated only by Mn 2+ and inhibited by Cd 2+ and Zn 2+ .

The Antarctic marine environment has unique characteristics such as isolation, low and even temperatures, as well as high levels of fluoride in the trophic web. The objective of the present study is to verify the effect of temperature, salinity and dietary fluoride in the diet on the levels of plasma constituents of the fish Notothenia rossii. The sample collection and the bioassay were conducted at Antarctic scientific station Comandante Ferraz. The fish were acclimated in an aquarium at temperatures of 0 and 4 °C; salinity of 35 and 20 psu, using feed with and without fluoride. The combination of these variables resulted in 8 experimental groups. The calcium serum levels were reduced in hyposaline stress and temperature elevation reduced the plasmatic levels of magnesium and chloride. The trophic fluoride isolatedly was not capable of changing the non-protein electrolytes levels.