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

Impacto de la contaminación orgánica sobre el fitoplancton de un arroyo de la llanura pampeana

“…Estos organismos liberan metabolitos (e.g., vitaminas) que favorecen el desarrollo de euglenofitas en cuerpos de agua con estas características. Por otro lado, estudios realizados sobre Lepocinclis acus y Phacus brachykentron demostraron que existe una relación entre la concentración de materia orgánica y la deformación de la morfología celular original (Conforti 1998;Bauer et al 2012;Nannavecchia et al 2014;Nannavecchia 2016). …”

“…Los cambios observados en Lepocinclis acus y Phacus longicauda coinciden con los observados en algunas especies por Conforti (1998), Bauer et al (2012), Nannavecchia et al (2014) y Nannavecchia 2016. En estos trabajos, las modificaciones se explican como respuesta al exceso de materia orgánica en el ambiente, lo cual coincide con las características generales del sistema estudiado.…”

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

“…On the other hand, the particular combination of morphological and ultrastructural modifications observed in L. acus cultured in enriched medium added to those described in P. brachykentron (Nannavecchia et al, 2014), raises serious questions and doubts on the validity of the usual euglenoids systematic characters as cell dimensions, number and paramylon shape. Several molecular studies have shown that a revision of the euglenoids taxonomy is necessary (Linton et al, 2000(Linton et al, , 2010Marin et al, 2003;Nudelman et al, 2003;Brosnan et al, 2005;Triemer et al, 2006;Kosmala et al, 2009;Karnkowska-Ishikawa et al, 2012Kim et al, 2013Kim et al, , 2015Kim and Shin, 2014;Łukomska-Kowalczyk et al, 2015;Bicudo and Menezes, 2016).…”

“…This response to an increase in cell volume was different in elastic species such as Euglena gracilis (Bertaux and Valencia, 1973) or a rigid one as Phacus brachykentron (Nannavecchia et al, 2014), where strips became wider, but no replication were observed. The existence of these different development response patterns in respect to similar environmental conditions could be an important evolutionary difference among euglenoids.…”

“…L. acus and other euglenoids species cultured or sampled in enriched medium and studied with light microscopy (Haughey, 1970;Conforti, 1998;Bauer et al, 2012;Nannavecchia et al, 2014) showed important morphological changes that were related to an increase in the number or size of paramylon grains. Precise biometric measurements have revealed significant statistical differences in the dimensions and number of the grains between the treated and control specimens.…”