Natasha Schvezov | Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Centro Austral de Investigaciones Científicas (CADIC) (original) (raw)

Papers by Natasha Schvezov

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2015

Revista de biología marina y oceanografía, 2013

Resumen.-En el sur de Sudamérica Lithodes santolla y L. confundens representan las especies de ce... more Resumen.-En el sur de Sudamérica Lithodes santolla y L. confundens representan las especies de centollas más apreciadas, debido a sus altos rendimientos y aceptación en los mercados. Desde un punto de vista fisiológico, las especies reactivas del oxígeno (ROS) son continuamente producidas como productos de la respiración celular. Estos ROS se transforman en metabolitos menos tóxicos por medio de enzimas antioxidantes. El objetivo fue determinar en Lithodes santolla (del Golfo San Jorge) y L. confundens (de la costa atlántica de Tierra del Fuego) el nivel de base de la actividad enzimática antioxidante y los niveles de peroxidación de lípidos. Las enzimas catalasa (CAT) y glutatión-S-transferasa (GST) y la peroxidación de lípidos se midieron en branquias, músculo y hepatopáncreas. Ambas especies mostraron actividad enzimática antioxidante, mientras que las branquias presentaron la mayor actividad enzimática de CAT. La actividad de CAT y GST fue mayor en L. confundens en el músculo y branquias respectivamente, comparado con L. santolla; mientras que la peroxidación de lípidos fue menor en ambos órganos. Estas diferencias entre ambas especies sugieren que L. confundens sería más eficiente ante situaciones de estrés oxidativo, debido probablemente a los periodos de anoxia que experimenta durante las bajas mareas de primavera. Además, estas diferencias podrían ser atribuidas a características intrínsecas de adaptación de cada especie de centolla y/o a condiciones ambientales de cada área de estudio en particular. Parámetros como CAT, GST y peroxidación de lípidos podrían proponerse como biomarcadores de estrés oxidativo en Lithodes santolla y L. confundens.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2013

Several physiological processes can induce daily variations in aerobic metabolism. Lithodes santo... more Several physiological processes can induce daily variations in aerobic metabolism. Lithodes santolla is a decapod crustacean of special concern since it is a sub-Antarctic species of commercial interest. The aim of this work was to study in L. santolla the daily variations in levels of enzymatic and non-enzymatic antioxidants, lipid peroxidation and protein oxidation, and haemolymphatic pH. Males of L. santolla of commercial size were randomly dissected every 4 h during a period of 24 h. Enzymatic activities of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase and glutathione peroxidase were determined in samples of gills, muscle, hepatopancreas and haemolymph. Ascorbic acid, total glutathione, lipid peroxidation and protein oxidation were also determined in all tissues. Gills showed the highest enzymatic activity and hepatopancreas the highest concentration of non-enzymatic antioxidants. Maximum antioxidant activity was during the dark phase in gills and during the photophase in the haemolymph. Muscle showed significant daily variations, with peaks during the photophase and scotophase. Overall, an antioxidant protective mechanism is present in all tissues, where SOD and CAT represent the first line of defense. The defense mechanism in L. santolla seems to be more active during the dark phase, with slight differences among the analyzed tissues, indicating a higher metabolic rate.

Ecotoxicology and Environmental Safety, 2011

A coastal system (Ushuaia Bay, Argentina) impacted by anthropogenic activities was studied by the... more A coastal system (Ushuaia Bay, Argentina) impacted by anthropogenic activities was studied by the response of local amphipods (Parmorea sp., Gammaridae) to the exposure of coastal sediments in a laboratory assay. Four coastal areas with different loadings of contaminants and one considered as reference were studied. Organic matter, carbohydrates, proteins and heavy metals were measured in sediment samples. Organisms were exposed to sediments for seven days and catalase (CAT), glutathione S-transferase (GST), acetylcholinesterase (AChE) and lipid peroxidation (LPO) were measured afterward. Amphipods exhibited an activation of GST and inhibition of AChE in most impacted areas. Principal Component Analysis (PCA) was conducted in order to associate the biological responses with sediment metal concentration and its eutrophicated status. Levels of Cd and Cr were associated with the inhibition of AChE and with the enhancement of GST. CAT and LPO were enhanced in most areas, but no link was found with the contaminants studied by PCA, suggesting that other parameters present in sediments not included in the PCA affect the amphipods. The most impacted area corresponds to Nautical Club station, with a highly eutrophicated status and high content of metals, where amphipods after the exposure were affected in a biochemical level.

Food Science and Technology

Tetragonisca fiebrigi, is a bee of the subfamily Meliponidae traditionally known as Yateí. Ots ho... more Tetragonisca fiebrigi, is a bee of the subfamily Meliponidae traditionally known as Yateí. Ots honey differs from the honey produced by Apis mellifera because it is less viscous, more acidic, has sweetness and particular aromas. Ot is important to know the behavior of yatei honey in different storage conditions, in order to preserve the characteristics of the honey and ensure the product as harmless. The objective was to determine the influence of temperature, packaging type and storage time of Yateí honey on antimicrobial properties, microbial (Total Mesophilic Aerobic and Mold and Yeast Count) and physicochemical parameters (pH, hydroxymethylfurfural (HMF), acidity, moisture content and diastase), with methodology of national and international standards. The antimicrobial effect was variable against strains of the genus Staphylococcus aureus. The most significant microbiological quality levels were Mold and Yeast counts (> 10 2 CFU / g). The physicochemical parameters with the most significant values were acidity (t o : 42.5 meq acid/kg honey), moisture content (t o : 26%) and HMF (t o : 3.8mg/kg honey). Storage at refrigeration temperature maintained standard values close to Apis mellifera honey during 180 days; whereas at room temperature it was better to maintain antimicrobial power. No significant difference was found between plastic storage containers vs. glass.

We studied the recovery of males of the commercially important king crab Lithodes santolla (Molin... more We studied the recovery of males of the commercially important king crab Lithodes santolla (Molina, 1782) once re-immersed after 24 h of air exposure (T) at 8 °C. The studied parameters were the enzymatic defenses superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase; the non-enzymatic antioxidants ascorbic acid and total glutathione; the oxidative stress parameters lipid peroxidation and protein oxidation; and glucose and haemolymphatic pH. Samples of gills, muscle, hepatopancreas, and haemolymph were taken before re-immersion (T + 0 h) and at T + 0.5 h, T + 2 h, T + 8 h, and T + 24 h after reimmersion. A control group was not exposed to air. Acidification and hyperglycemia were generally observed after air exposure, indicating a change to anaerobic metabolism. At T + 0.5 h after re-immersion, the enzymatic antioxidant defense system in all tissues generally increased as a response to reperfusion. At T + 24 h after re-immersion the antioxidant defense system and levels of glucose and pH recovered to values observed in the control group in all tissues. Lipid peroxidation and protein oxidation were variable but in none of the tissues did the parameters exceed those of the control group. Results indicate the capability of recovery of L. santolla and the possibility of transporting crabs without water.

Ecotoxicology and Environmental Safety, 2011

a b s t r a c t A coastal system (Ushuaia Bay, Argentina) impacted by anthropogenic activities wa... more a b s t r a c t A coastal system (Ushuaia Bay, Argentina) impacted by anthropogenic activities was studied by the response of local amphipods (Parmorea sp., Gammaridae) to the exposure of coastal sediments in a laboratory assay. Four coastal areas with different loadings of contaminants and one considered as reference were studied. Organic matter, carbohydrates, proteins and heavy metals were measured in sediment samples. Organisms were exposed to sediments for seven days and catalase (CAT), glutathione S-transferase (GST), acetylcholinesterase (AChE) and lipid peroxidation (LPO) were measured afterward. Amphipods exhibited an activation of GST and inhibition of AChE in most impacted areas. Principal Component Analysis (PCA) was conducted in order to associate the biological responses with sediment metal concentration and its eutrophicated status. Levels of Cd and Cr were associated with the inhibition of AChE and with the enhancement of GST. CAT and LPO were enhanced in most areas, but no link was found with the contaminants studied by PCA, suggesting that other parameters present in sediments not included in the PCA affect the amphipods. The most impacted area corresponds to Nautical Club station, with a highly eutrophicated status and high content of metals, where amphipods after the exposure were affected in a biochemical level.

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2015

Revista de biología marina y oceanografía, 2013

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2013

Ecotoxicology and Environmental Safety, 2011

Food Science and Technology

Ecotoxicology and Environmental Safety, 2011