Search results for "chlorophyta"

Lichen microalgae are sensitive to environmental concentrations of atrazine

2017

The identification of new organisms for environmental toxicology bioassays is currently a priority, since these tools are strongly limited by the ecological relevance of taxa used to study global change. Lichens are sensitive bioindicators of air quality and their microalgae are an untapped source for new low-cost miniaturized bioassays with ecological importance. In order to increase the availability of a wider range of taxa for bioassays, the sensitivity of two symbiotic lichen microalgae, Asterochloris erici and Trebouxia sp. TR9, to atrazine was evaluated. To achieve this goal, axenic cultures of these phycobionts in suspension were exposed to a range of environmental concentrations of …

Lichen rehydration in heavy metal polluted environments: Pb modulates the oxidative response of both Ramalina farinacea thalli and its isolated micro…

2014

Lichens are adapted to desiccation/rehydration and accumulate heavy metals, which induce ROS especially from the photobiont photosynthetic pigments. Although their mechanisms of abiotic stress tolerance are still to be unravelled, they seem related to symbionts' reciprocal upregulation of antioxidant systems. With the aim to study the effect of Pb on oxidative status during rehydration, the kinetics of intracellular ROS, lipid peroxidation and chlorophyll autofluorescence of whole Ramalina farinacea thalli and its isolated microalgae (Trebouxia TR1 and T. TR9) was recorded. A genetic characterization of the microalgae present in the thalli used was also carried out in order to assess possib…

Phylogenetic relationship of the green alga Nanochlorum eukaryotum deduced from its chloroplast rRNA sequences.

1995

The marine green coccoidal alga Nanochlorum eukaryotum (N.e.) is of small size with an average diameter of 1.5 microns. It is characterized by primitive-appearing biochemical and morphological properties, which are considerably different from those of other green algae. Thus, it has been proposed that N.e. may be an early developed algal form. To prove this hypothesis, DNA of N.e. was isolated by a phenol extraction procedure, and the chloroplast DNA separated by preparative CsCl density-gradient centrifugation. The kinetic complexity of the nuclear and of the chloroplast DNA was evaluated by reassociation kinetics to 3 x 10(7) bp and 9 x 10(4) bp, respectively. Several chloroplast genes, i…

A single primer pair gives a specific ortholog amplicon in a wide range of Cyanobacteria and plastid-bearing organisms: applicability in inventory of…

2010

The scarcity of universally applied molecular markers for algae has resulted in the development of multiple, independent and not easily comparable systems. The goal of this work is to increase the number of available molecular markers and to generate easily comparable systems. Thereby, we have designed a primer pair capable of amplifying a broad range of organisms: Cyanobacteria, Chlorophyta, Chlorarachniophyta, Cryptophyta, Euglenida, Glaucophyta, Rhodophyta, Stramenopiles and Streptophyta including plants. This primer pair can amplify a portion of the 23S rRNA gene with sufficient variability to identify reference material form collections across a broad range of taxa and perform phylogen…

The effects of anthropogenic organic matter inputs on stable carbon and nitrogen isotopes in organisms from different trophic levels in a southern Me…

2005

Stable isotope ratios were used to determine the impact of anthropogenically derived organic matter from onshore and offshore fish farming and a sewage outfall on organisms at different trophic levels (primary producers and consumers) on the south-east coast of Sicily (Italy, Mediterranean). Representative macroalgae and consumers were collected in three sampling locations: "Impact" and two putative "Controls" sited to the north of the impacted location. While delta(13)C values of both organic matter sources and consumers varied little between locations, delta(15)N spatial variability was higher and delta(15)N was shown to be a good descriptor of organic enrichment and uptake of anthropogen…

Comparative study of the toxicity of molinate for freshwater organisms.

2003

Ecotoxicity of sediments in rivers: Invertebrate community, toxicity bioassays and the toxic unit approach as complementary assessment tools

2015

The determination of the real toxicity of sediments in aquatic ecosystems is challenging and necessary for an appropriate risk assessment. Different approaches have been developed and applied over the last several decades. Currently, the joint implementation of chemical, ecological and toxicological tools is recommended for an appropriate and successful toxicity risk assessment. We chose the combination of the toxic unit approach with acute pore water tests (Vibrio fischeri, Pseudokirchneriella subcapitata and Daphnia magna) and whole-sediment exposure tests (V. fischeri, Chironomus riparius), together with invertebrate community composition (multivariate analyses) to detect short and long-…

Application of Toxkit microbiotests for toxicity assessment in soil and compost

2004

The potential of Toxkit microbiotests to detect and analyze pollution in agricultural soil and the quality of compost was studied. The toxicity tests used included seed germination biotests using cress salad (Lepidum sativum L.), tomato (Lycopersicum esculentum L.), and cucumber (Cucumis sativus L.), and the Toxkit microbiotests included those with microalgae (Selenastrum capricornutum), protozoa (Tetrahymena thermophila), crustaceans (Daphnia magna, Thamnocephalus platyurus, and Heterocypris incongruens), and rotifers (Brachionus calyciflorus). Experiments on compost were undertaken in a modified solid-state fermentation system (SSF) and under field conditions (in a windrow). To promote th…

Accumulation of Tetradifon in an Algae ( Nannochloris oculata ) and the Cladoceran, Daphnia magna

1996

Chronic toxicity of fenitrothion to an algae (Nannochloris oculata), a rotifer (Brachionus calyciflorus), and the cladoceran (Daphnia magna).

1996

Chronic toxicity studies were conducted with an algae (Nannochloris oculata), a rotifer (Brachionus calyciflorus), and a cladoceran (Daphnia magna) to determine their relative sensitivities to the organophosphorus insecticide fenitrothion. The cladoceran D. magna was the most sensitive of the three species. The no observed effect concentrations (NOECs) for the study with the algae (1.0 mg/liter) and for the rotifer (1.0 mg/liter) were higher than the NOEC (0.009 microgram/liter) and the LC50 of 24 hr (0.067 microgram/liter) for D. magna. Most of the algal populations were not initially affected by exposure to fenitrothion. Pesticide concentrations higher than 1.0 mg/liter significantly redu…