Dinámica poblacional del cirripedio Balanus amphitrite Darwin en un área afectada por contaminación cloacal

Fil:Calcagno, Javier Angel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Biodiversity of Agaricomycetes basidiomes associated to Salix and Populus (Salicaceae) plantations

Although plantations have an artificial origin, they modify environmental conditions that can alter native fungi diversity. The effects of forest management practices on a plantation of willow (Salix) and poplar (Populus) over Agaricomycetes basidiomes biodiversity were studied for one year in an island located in Paraná Delta, Argentina. Dry weight and number of basidiomes were measured. We found 28 species belonging to Agaricomycetes: 26 species of Agaricales, one species of Polyporales and one species of Russulales. Our findings suggest that forest management practices on plantations of willow and poplar do not affect either the abundance or diversity of Agaricomycetes basidiomes.Fil: Romano, Gonzalo Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Calcagno, Javier Angel. Universidad Maimonides. Area de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomedicos, biotecnológicos, Ambientales y Diagnostico. Departamento de Ciencias Naturales y Antropologicas; ArgentinaFil: Lechner, Bernardo Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; Argentin

Composition, density, and biomass of salpidae and chaetognatha in the southwestern Atlantic Ocean (34.5°S-39°S)

Salps and chaetognaths constitute an important fraction of the macrozooplankton and have a prominent role in the marine food web. In our study, we analyzed the species composition, density, and biomass in an area of the southern Atlantic Ocean during the austral winters of 1999, 2000, and 2001. The most abundant and frequent species were the salpids Ihlea magalhanica (Apstein, 1894) and Iasis zonaria (Pallas, 1774), and the chaetognaths Parasagitta friderici (Ritter-Zahony, 1911) and Serratosagitta tasmanica (Thomson, 1947). Chaetognaths were found in over 80% of the stations throughout the three winters, reaching up to 67 individuals (ind) m -3. Salps were found surviving at low population densities in 2000 and 2001, but in 1999, there were mass occurrences of I. zonaria and I. magalhanica, reaching densities of 301 and 123 ind m -3, respectively. To estimate biomass in C units, the relationship between dry weight and size was calculated for S. tasmanica and for solitaries and aggregates of I. zonaria and I, magalhanica. The biomass of salps and chaetognaths (as mg C m -3) over the shelf during the three consecutive winters was strongly related to prevailing physical and biological conditions. In 1999, the greatest contribution to macrozooplankton biomass corresponded to salps, while in 2000 and 2001, chaetognaths dominated the biomass. In swarm conditions, like in 1999, I. zonaria and I. magalhanica widely dominated over copepods and chaetognaths, producing an increase in the quantity of available C of up to 60 times in relation to the periods with very low population densities.Fil: Daponte, María Cristina. Universidad de Buenos Aires; ArgentinaFil: Calcagno, Javier Angel. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Acevedo Luque, María José de Jesús. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martos, Patricia. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Machinandiarena, Laura. Universidad Nacional de Mar del Plata; ArgentinaFil: Esnal, Graciela Beatriz. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Absence of a prezygotic behavioural barrier to gene flow between the two sympatric morphs of the squat lobster Munida gregaria (Fabricius, 1793) (Decapoda: Anomura: Galatheidae).

Munida gregaria and M. subrugosa have been considered two different species for more than a century; however, after a recent molecular phylogenetic study, they are considered a single polymorphic species. Yet, the use of markers to diagnose species may be misleading when divergence between species is recent, since a speciation event may be obscured by the retention and stochastic sorting of ancestral polymorphisms. The morphs gregaria and subrugosa of Munida gregaria constitute an interesting case for the study of behavioural isolation since they are sympatric, breed at the same time of the year, and might have experienced a recent speciation. Mating behaviour observations and mate choice mating trials were conducted in order to investigate the potential existence of a behavioural prezygotic barrier to gene flow between these two morphs. Since factors involved in mate choice in galatheids are unknown, the four possible combinations of the two different morphs in trios were used to test for the existence of mate choice. Video recordings of all the possible trio combinations revealed that there was cross-attraction between males and females of different morphs. Females bearing partial broods participated in encounters as well as non-ovigerous females. The frequency and duration of homo- and heterotypic encounters were registered, and a reproductive isolation index was calculated for each variable for each trio. The isolation indexes calculated were not different from zero indicating random mating, and were not affected by the composition of the trio or the partial ovigerous condition of females. These results provided evidence of the absence of behavioural prezygotic barriers to gene flow between the morphs gregaria and subrugosa of M. gregaria.Fil: Perez Barros, Patricia. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecologia, Genetica y Evolucion. Ecologia de Organismos Bentonicos Marinos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Calcagno, Javier Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Preliminary findings on the effect of melatonin on the clinical outcome of cataract surgery in dogs

OBJECTIVE: Cataract is the most prevalent cause of blindness in dogs. Phacoemulsification (PE) is currently the surgical treatment of choice to remove the opaque lens; however, it is associated with varying degrees of postoperative inflammation. We assessed the effect of melatonin on postoperative complications of canine cataract surgery. ANIMAL STUDIED: Eleven diabetic and thirteen healthy owned dogs with cataracts. PROCEDURES: All dogs underwent cataract surgery by PE. The anti-inflammatory effect of melatonin was compared with the reference treatments: nonsteroidal anti-inflammatory drugs (NSAIDs) for diabetic dogs, and dexamethasone for nondiabetic dogs. Eyes were examined by means of clinical evaluation and intraocular pressure (IOP). RESULTS: In diabetic dogs, melatonin was more effective than topical and systemic NSAIDs in reducing the clinical score at 2, 7, and 20 days postsurgery, while it showed a similar efficacy to topical dexamethasone in dogs with hereditary cataracts. IOP decreased in all groups at 2 days postsurgery, but this decrease reached statistical significance only in diabetic dogs treated with NSAIDs, and persisted at 7 days postsurgery in this group. Afterward, IOP returned to normal values in all groups. Melatonin decreased the occurrence of surgical sequelae in diabetic and nondiabetic dogs. CONCLUSIONS: These results indicate that melatonin might constitute a useful tool for reducing postoperative PE complications in dogs.Fil: Sande Casal, Pablo Horacio. Universidad de Buenos Aires. Facultad de Medicina. Laboratorio de Neuroquímica Retiniana y Oftalmología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Alvarez, Javier. Universidad de Buenos Aires. Facultad de Medicina. Laboratorio de Neuroquímica Retiniana y Oftalmología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Calcagno, Javier Angel. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rosenstein, Ruth Estela. Universidad de Buenos Aires. Facultad de Medicina. Laboratorio de Neuroquímica Retiniana y Oftalmología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; Argentin

Reproduction and oxidative metabolism in the brooding sea star Anasterias antarctica (Lütken, 1957)

The oral-brooding sea star Anasterias antarctica is distributed on the coasts of South Patagonia and north of Antarctic Peninsula. This species is a potential predator of shellfish Mytilus chilensis, an important commercial resource for Beagle Channel region. The aims of this work were to study the variation in the gonad index (GI), to establish the brooding season, to determine the reproductive effort of both sexes, and to assess the concentration of liposoluble antioxidants and production of reactive oxygen species (ROS) in male and female gonads and embryos of A. antarctica during the year. Four samplingswere performed: three during the brooding season and one during the non-brooding season. Individuals sampled during the brooding season were assigned to one of the three groups: brooding females, non-brooding females, and males. Individuals sampled during the nonbrooding seasonwere assigned to one of the three groups: sexuallymature females, sexually non-mature females and males. Histological observations allowed determining that only females incubate the embryos on the oral surface for seven months. Males showed a strategy characteristic of broadcast spawners, whereas females spawned only a small number of eggs, as it is characteristic of brooders and as observed in other species of asteroids. Males show a significant increase in GI before spawning (from 1% to 15%) and then a marked decrease. During gametogenesis, testes showed a low level of β-carotene and high production of ROS. Between May and October; brooding and non-brooding females showed similar values of ROS production and concentration of antioxidants. Mature females had a significantly higher GI and lipid soluble antioxidant concentration than non-mature females. ROS production was higher in non-mature females. In A. antarctica embryos, ROS production increased and liposoluble antioxidant defenses decreased along development. The reproductive effort of males was about 25% lower than that of females, probably because of brooding costs. Gonadal maturation occurred in summer in both sexes, in concordance with an increase in the concentration of liposoluble antioxidants and the minimum values of ROS production. This suggests a strategy of oxidative damage prevention and gamete protection through allocation of antioxidants to mature gonads. The β-carotene and α-tocopherol accumulation in ovaries would protect not only maturing oocytes but also embryos, given that these antioxidants would be transferred to eggs. Along the reproductive cycle, A. antarctica gonads are protected from oxidative processes, mainly by β-carotene. Further, during gonad maturation, protection increases with the increase in α-tocopherol concentration and the decrease in ROS, whose highest and lowest values coincide with maximum gonadal maturation.Fil: Perez, Analia Fernanda. Universidad Maimónides. Area de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Boy, Claudia Clementina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Calcagno, Javier Angel. Universidad Maimónides. Area de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Malanga, Gabriela Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular; Argentin

Is Munida gregaria (Crustacea: Decapoda: Munididae) a truly transpacific species?

The “East Pacific Barrier” has been recognized as the World’s largest marine biogeographic barrier. Munida gregaria is the only species of its family with transpacific populations; however, it still remains to be elucidated whether these two distantly located populations belong to the same species. In this study, we investigated the genetic cohesion of M. gregaria across the East Pacific Barrier by analyzing mitochondrial markers. Cytochrome oxidase subunit I and NADH dehydrogenase subunit 1 genes were sequenced for individuals from different areas, i.e., the southeast Pacific, the southern tip of South America, the southwest Atlantic, and the southwest Pacific. A median-joining network, pairwise F STs, genetic diversity statistics, and neutrality tests were computed. Our results, i.e., the absence of different haplogroups on both sides of the East Pacific Barrier and existence of shared haplotypes, showed that populations on both sides of this barrier belong to the same species. At a population genetic level, our results suggest that individuals from both regions have been connected, since although some differentiation was found between the southern tip of South America and the southwest Pacific, the southeast Pacific and southwest Atlantic showed no signs of differentiation from the southwest Pacific. In addition, our results provided evidence of a population expansion in southern South America during the Pleistocene. The role of Pleistocene glaciations and the Antarctic Circumpolar Current in shaping the distribution of sub-Antarctic marine invertebrates is discussed.Fil: Perez Barros, Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Calcagno, Javier Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Confalonieri, Viviana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Effect of seasonality on oxidative stress responses and metal accumulation in soft tissues of Aulacomya atra, a mussel from the South Atlantic Patagonian coast

This study investigated the effects of pollution and its interaction with temperature on the oxidative status of the ribbed mussel Aulacomya atra in the southern Atlantic Patagonian coast. Animals were collected from four sites with different degree and type of human activity impact, during the summer and winter of 2011. Seawater chromium, copper, manganese, nickel and zinc concentrations were measured, as well as metal accumulation, lipid peroxidation, protein oxidation, reduced glutathione levels, and enzymatic activities of superoxide dismutase and glutathione-S- transferase in gills and digestive glands. Metal bioacumulation and oxidative stress responses in both tissues were generally higher in mussels from harbor areas. Water temperature had a remarkable effect on gill SOD activity and protein oxidation during winter in mussels from all locations. Methodologically, we conclude that measuring both metal bioaccumulation and oxidative stress responses allowed for a more accurate assessment of the biological effects of metal present in seawater.Fil: Di Salvatore, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Calcagno, Javier Angel. Universidad Maimónides. Area de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Ortiz, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Rios, Maria del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Sabatini, Sebastian Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentin