Ultrastructural Alterations in Lepocinclis acus (Euglenophyta) Induced by Medium with High Organic Matter Content

Ultrastructural changes induced by exposure to excess of organic matter were studied in Lepocinclis acus (ex Euglena acus). The cells isolated from the Matanza River, Buenos Aires, Argentina, were grown in soil water medium (SWM). When transferred to medium enriched with Bacteriological Peptone OXOID®, marked body deformation and a significant shortening and widening of the cells was observed. These changes were unexpected in a species with quite rigid cells, a condition previously shown in studies of the pellicle fine structure. Transmission electron microscopy observations suggest that cellular deformation might be facilitated by an increase in strip number, whereas in the original strips normal ultrastructure was maintained. An increase in number and volume of paramylon grains and vacuoles, as well as the presence of membrane whorls in vacuoles was observed. The fine structure of organisms grown in medium with and without organic matter enrichment was compared, and the systematic and ecological importance of morphological changes triggered by cell deformation was discussed.Fil: Conforti, Visitacion Teresa D.. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Ruiz, Laura Beatriz. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Leonardi, Patricia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

Trachelomonas (Euglenophyta) from a eutrophic reservoir In Central Mexico

This study provides valuable information on the ultrastructure and environmental conditions of the Trachelomonas Ehr. (Euglenophyceae) genus in the Guadalupe Dam, a eutrophic reservoir located in the suburbs of Mexico City, which receives a considerable volume of wastewaters. Specimens were collected at surface level between November 2005 and May 2006. Using LM and SEM twelve taxa from phytoplankton were identified of which, 9 are new records for Mexico. The reservoir is warm monomictic, with basic pH values (7.4-10.1), a high concentration of chlorophyll a(18-101 microg l(-1), a permanent anoxic bottom, specific conductivity (K25) of 205 to 290 microS cm(-1), N-NO3, 0.19-1.2 mg l(-1) and P-PO4 0.22-1.6 mg l(-1). Water temperature was 15.6-23.0 degrees C. Most of the Trachelomonas species were found during the dry season, when concentrations of organic matter, nitrogen and phosphorus as well as the temperature were the highest. Higher species richness was also associated with the warmer months. This research contributes to increase our knowledge on Trachelomonas in Mexico and constitutes the first detailed description of lorica ultrastructure of 12 taxa that grow in a body of water with high concentration of nutrients and a moderate amount of mineral contents.Fil: Garduño Solorzano, Gloria. Universidad Nacional Autonoma de Mexico. Facultad de Estudios Superiores de Iztacala; MéxicoFil: Oliva Martinez, Maria Guadalupe. Universidad Nacional Autonoma de Mexico. Facultad de Estudios Superiores de Iztacala; MéxicoFil: Lugo Vázquez, Alfonso. Universidad Nacional Autonoma de Mexico. Facultad de Estudios Superiores de Iztacala; MéxicoFil: Mendoza Garfías, María Berenit. Universidad Nacional Autonoma de Mexico. Facultad de Estudios Superiores de Iztacala; MéxicoFil: Quintanar Zuñiga, Rafael Emiliano. Universidad Nacional Autonoma de Mexico. Facultad de Estudios Superiores de Iztacala; MéxicoFil: Conforti, Visitacion Teresa D.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Ultrastructure of the lorica of species (Euglenophyta) from New Jersey, USA

A floristic and ultrastructural study on Trachelomonas was made in the piedmont region of central New Jersey, USA, where a large number of euglenoid taxa are contained in several freshwater bodies. Abundant and unusual loricated species were found during the observations of samples from these ponds. From the forty-seven taxa determined, eighteen are reported for the first time in the USA. Detailed ultrastructure examination with scanning electron microscopy (SEM) yielded interesting results. Among the taxa described in this work T. compacta var. parvicollis is proposed as new variety, and four are considered affinis to described taxa, T. bacillifera var. collifera, T. granulosa, T. raciborskii var. incerta and T. verrucosa var. verrucosa fo. irregularis, respectively. Twelve taxa are examined and documented, for the first time ever, with original SEM micrographs.Fil: Conforti, Visitacion Teresa D.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Ultrastructural study of Strombomonas (Euglenophyta) from the province of Chaco (Argentina)

Nine taxa of Strombomonas Deflandre (Euglenophyta) from the province of Chaco (Argentina) have been examined with scanning elctron microscopy (SEM). Details of the lorica ultrastructure are described and illustrated, five of them for the first time with SEM: Strombomonas conforti Zalocar de Domitrovic, S. Eurystoma (Stein) Popova, S. longicauda (Swirenko) Deflandre, S. pizarroi Zalocar de Domitrovic and S. urceolata (Stokes) Deflandre. For the other taxa (S. tellii Zalocar de Domitrovic, S. scabra var. hiperintermedia Conforti, S. diptera Zalocar & Tell and S. tetraptera (Balech & Dastugue) additional comments on relevant morphological characteristics are furnished.Estudio ultraestructural de Strombomonas (Euglenophyta) de la provincia de Chaco (Argentina). En este trabajo se examinaron con microscopio electrónico de barrido (MEB) nueve taxones del género Strombomonas Deflandre (Euglenophyta), colectados en cuerpos de agua de la provincia del Chaco (Argentina). Se describe e ilustra la ultraestructura de sus lórigas, de las cuales cinco son analizadas por primera vez con esta técnica: Strombomonas confortii Zalocar de Domitrovic, S. eurystoma (Stein) Popova, S. longicauda (Swirenko) Deflandre, S. pizarroi Zalocar de Domitrovic y S. urceolata (Stokes) Deflandre. Para los laxa restantes (S. tellii Zalocar de Domitrovic, S. scabra var. Hiperintermedia Conforti, S. diptera Zalocar & Tell y S. tetraptera Balech & Dastugue), se amplía su descripción y se detacan algunas diferencias con observaciones previasFil: Conforti, Visitacion Teresa D.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Zalocar, Yolanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Trachelomonas iberaensis sp. nova (Euglenophyta) from Iberá System (Argentina)

In this work we describe on the basis of light and scanning electron microscopy a new species of the genus Trachelomonas (Euglenophyta), Trachelomonas iberaensis sp. nova, from Iberá System, Corrientes, ArgentinaFil: Zalocar, Yolanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Conforti, Visitacion Teresa D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentin

Euglenophyta from a stream of Pampean plain subjected to anthropic effects: Aº Rodriguez, Buenos Aires, Argentina

Eighty nine taxa of Euglenophyta, sampled in Rodríguez Stream, Buenos Aires, Argentina, 2 belonging to the genus Euglena Ehr., 7 to Lepocinclis Perty, 14 to Phacus Duj., 40 to Strombomonas Defl. and 26 to Trachelomonas Ehr. have been identified. Besides 12 loricate taxa were examined by scanning electron microscopy (SEM). Details of their envelope ultrastructure are illustrated.Fil: Conforti, Visitacion Teresa D.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ohirko, Erica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gomez, Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentin

An in situ test to explore the responses of Scenedesmus acutus and Lepocinclis acus as indicators of the changes in water quality in lowland streams

This bioassay was designed with the aim of exploring the responses of two wild planktonic microalgae exposed in situ (72. h) as indicators of the changes in water quality. Monocultures of both strains within dialysis membrane bags were placed at two sites in a small lowland stream. Site 1 is located at a suburban area with low horticultural activity and Site 2 is impacted by toxic industrial discharges and urban land use.There was a decrease in population growth of both species at Site 2 compared with Site 1. The comparison of the algae exposed in situ with the normal specimens cultured at the laboratory indicated a significant increase in the cellular volume for both species at both sites. Abnormal shape was recorded at both sites, the percentage being significantly greater for Scenedesmus acutus at Site 2. Significant changes in pyrenoids size were observed in S. acutus and in the percentage of fragmented nuclei in Lepocinclis acus. Also in the latter abnormal paramylon grains were observed. These responses were accentuated at Site 2.This bioassay was sensitive, short term, low cost, and therefore is a suitable tool to contribute with the monitoring and ecological risk assessment of lowland streams. © 2011 Elsevier Inc.Fil: Bauer, Delia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Conforti, Visitacion Teresa D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Ruiz, Laura Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Gomez, Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentin

Ultrastructural alterations in Phacus brachykentron (Euglenophyta) due to excess of organic matter in the culture medium

Morphological and ultrastructural changes induced by exposure to excess of organic matter were analyzed in Phacus brachykentron (Pochm.). The cells were isolated from sites in Matanza River, Buenos Aires, Argentina, which have a high degree of organic matter contamination coming from waste waters discharges of the meat industry. Master strains were cultured on soil water medium and a toxicity bioassay was performed. As a result of the enriched medium, several morphological and ultrastructural cellular alterations were observed by optical, scanning, and transmission electron microscopy. Among these, we can point out changes in cell dimensions, remarkable widening of some pellicle bands, increased number and volume of paramylon grains, displacement of the nucleus from the central to the lateral position, some chloroplasts with their thylakoids disordered, and cell lysis. The response to organic enrichment was very fast, i.e. during the 48 h of the bioassay. Therefore, any significant increase of organic matter would rapidly affect wild euglenoids. Our results suggest that the alterations observed, such as the presence of large intracellular paramylon bodies or the deformation of euglenoid cells in natural samples, have the potential to be used as environmental bioindicators.Fil: Nannavecchia, Paula Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Tolivia, Analía Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Conforti, Visitacion Teresa D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentin

Chromium induced stress conditions in heterotrophic and auxotrophic strains of Euglena gracilis

Oxidative stress parameter and antioxidant defense compound as well as enzyme activity were studied in relation to different Cr(VI) concentrations (0, 10, 20, 40μM) in two strains of Euglena gracilis, one isolated from a polluted river (MAT) and the other acquired from a culture collection (UTEX). Chromium toxicity was measured in the auxotrophic and obligated heterotrophic variants of the two strains. Chromium uptake was higher in auxotrophic cultures, reflected by their higher cell proliferation inhibition and lower IC50 levels compared to heterotrophic ones. In the Cr(VI) treatments a reduction of chlorophyll a and b ratio (Chl a/Chl b) was observed, the ratio of protein to paramylon content was augmented, and total lipid content increased, having the auxotrophic strains the highest values. TBARS content increased significantly only at 40μM Cr(VI) treatment. Unsaturated fatty acids also increased in the Cr(VI) treatments, with the higher storage lipid (saturated acids) content in the heterotrophic cells. The antioxidant response, such as SOD activity and GSH content, increased with chromium concentration, showing the highest GSH values in the heterotrophic cultures and the SOD enzyme participation in chromium toxicity. The MAT strain had higher IC50 values, higher carbohydrate and saturated acid content, and better response of the antioxidant system than the UTEX one. This strain isolated from the polluted place also showed higher GSH content and SOD activity in control cells and in almost all treated cultures. SOD activity reached a 9-fold increase in both MAT strains. These results suggest that tolerance of MAT strain against Cr(VI) stress is not only related to GSH level and/or biosynthesis capacity but is also related to the participation of the SOD antioxidant enzyme.Fil: Rocchetta, Iara. 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. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Mazzuca, Marcia. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Conforti, Visitacion Teresa D.. 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. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Balzaretti, Vilma Teresa. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: de Molina, María del Carmen Ríos. 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. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentin

Epibiont algae on planktic microcrustaceans from a subtropical shallow lake (Argentina)

Studies on taxonomy and seasonal variations of density and biomass were carried out over a year on epibiont algae on planktic microcrustaceans from a subtropical shallow lake (Corrientes, Argentina). Four taxa, 3 Chlorophyta and 1 Euglenophyta, were documented. Among them, Chloromonas anuraeae (KOR-SHIKOV) GERLOFF et ETTL and Chlorangiopsis systilis KORSHIKOV were docu-mented for the first time for South America, and Korshikoviella setosa(FILARSZ.) SILVA for the first time in Argentina. Colacium vesiculosum EHRENB. was the most frequent taxon observed. The infestation percentage was high in adult microcrus-taceans of calanoid copepods. The absence of a significant correlation between the density of epibionts and microcrustaceans or between both populations and the environmental variables suggests that epibiont algae might not play a key role in the regulation of planktic microcrustaceans.Fil: Zalocar, Yolanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Forastier, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Casco, Sylvina Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Conforti, Visitacion Teresa D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentin