Planarians as invertebrate bioindicators in freshwater environmental quality: the biomarkers approach

Knakievicz, Tanise

doi:10.5132/eec.2014.01.001

Cited by 45 publications

(24 citation statements)

References 88 publications

(101 reference statements)

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“…Freshwater planarians are metazoan flatworms which are bilaterally symmetrical. They belong to the phylum Platyhelminthes and lack a circulatory system, a respiratory system, and skeletal structures (Knakievicz, 2014; Reddien and Alvarado, 2004). They feed predominantly on insects, insect larvae, and other invertebrates.…”

Section: Introductionmentioning

confidence: 99%

Physiological evaluation of the behavior and epidermis of freshwater planarians (Girardia tigrina and Girardia sp.) exposed to stressors

et al. 2018

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Planarians are metazoan freshwater flatworms which are free-living organisms. Their body has pluripotent stem cell promoters of tissue regeneration capacity. The water temperature and the potential of hydrogen (pH) of lentic ecosystems are important factors involved in the distribution and abundance of these animals. Although the pH factor is directly related to the physiology and behavior of planarians, their adaptive and regenerating capacities still remain unknown. The Critical Thermal Maximum (CTM) is a very widespread method used in the evaluation of thermal tolerance. In this study, Girardia tigrina (Girard, 1850) and Girardia sp., a species found in Brazil, which is under study as a new species, had their epidermis assessed by scanning electron microscopy (SEM) to analyze their physiological structures before and after exposure to different stressors. SEM was used as a method to evaluate the planarians' epidermis as a result of the increasing temperature (CTM) and pH alterations, the latter with the use of a new methodology defined as Critical Hydrogen ion concentration Maximum (CHM). In increasing temperatures from 20°C to 37°C, both Girardia tigrina and Girardia sp. proved to be adaptable to thermal stress. Girardia sp. was shown to be more resistant to higher temperatures. However, Girardia tigrina was more resistant to extreme pH conditions (4.0 to 10.0). SEM analysis showed morphological differences among planarian species, such as the arrangement of the structures and cell types of the dorsal epidermis. Moreover, planarians demonstrated the ability to change the surrounding pH of their external environment in order to maintain the function of their physiological mechanisms, suggesting that these animals have a complex survival system, possibly related to protonephridia, flame cells and excretory pores..

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Section: Introductionmentioning

confidence: 99%

Physiological evaluation of the behavior and epidermis of freshwater planarians (Girardia tigrina and Girardia sp.) exposed to stressors

et al. 2018

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“…After exposure to water samples, different markers at the molecular (Prá et al. ) or organismal levels (Knakievicz ) can be used to assess the water pollution level and identify specific pollutants.…”

Section: Introductionmentioning

confidence: 99%

Planarian brain regeneration as a model system for developmental neurotoxicology

2016

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Freshwater planarians, famous for their regenerative prowess, have long been recognized as a valuable in vivo animal model to study the effects of chemical exposure. In this review, we summarize the current techniques and tools used in the literature to assess toxicity in the planarian system. We focus on the planarian's particular amenability for neurotoxicology and neuroregeneration studies, owing to the planarian's unique ability to regenerate a centralized nervous system. Zooming in from the organismal to the molecular level, we show that planarians offer a repertoire of morphological and behavioral readouts while also being amenable to mechanistic studies of compound toxicity. Finally, we discuss the open challenges and opportunities for planarian brain regeneration to become an important model system for modern toxicology.

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“…Understanding the effect of temperature is directly related to optimizing the planarian culture condition (Vila-Farré and Rink, 2018). They have also been proposed as inexpensive models for ecotoxicology studies (Knakievicz, 2014), and our study extends the scope to include the effect of a harmful substance on mitochondrial metabolism when the animal experiences thermal variation. Furthermore, the small size of the planarians allows the study of the process in the whole animal, rather than in specific tissues; this is essential to understand the overall energy production capacity of the organism facing sudden and long-term changes in temperature.…”

Section: Introductionmentioning

confidence: 88%

Adjustments in control of mitochondrial respiratory capacity while facing temperature fluctuations

Scott

Matthew

Woolcock

et al. 2019

Journal of Experimental Biology

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As the world's climate changes, life faces an evolving thermal environment. Mitochondrial oxidative phosphorylation (OXPHOS) is critical to ensure sufficient cellular energy production, and it is strongly influenced by temperature. The thermally induced changes to the regulation of specific steps within the OXPHOS process are poorly understood. In our study, we used the eurythermal species of planarian Dugesia tigrina to study the thermal sensitivity of the OXPHOS process at 10, 15, 20, 25 and 30°C. We conducted cold acclimation experiments where we measured the adjustment of specific steps in OXPHOS at two assay temperatures (10 and 20°C) following 4 weeks of acclimation under normal (22°C) or low (5°C) temperature conditions. At the low temperature, the contribution of the NADH pathway to the maximal OXPHOS capacity, in a combined pathway (NADH and succinate), was reduced. There was partial compensation by an increased contribution of the succinate pathway. As the temperature decreased, OXPHOS became more limited by the capacity of the phosphorylation system. Acclimation to the low temperature resulted in positive adjustments of the NADH pathway capacity due, at least in part, to an increase in complex I activity. The acclimation also resulted in a better match between OXPHOS and phosphorylation system capacities. Both of these adjustments following acclimation were specific to the low assay temperature. We conclude that there is substantial plasticity in the mitochondrial OXPHOS process following thermal acclimation in D. tigrina, and this probably contributes to the wide thermal range of the species.

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Planarians as invertebrate bioindicators in freshwater environmental quality: the biomarkers approach

Cited by 45 publications

References 88 publications

Physiological evaluation of the behavior and epidermis of freshwater planarians (Girardia tigrina and Girardia sp.) exposed to stressors

Physiological evaluation of the behavior and epidermis of freshwater planarians (Girardia tigrina and Girardia sp.) exposed to stressors

Planarian brain regeneration as a model system for developmental neurotoxicology

Adjustments in control of mitochondrial respiratory capacity while facing temperature fluctuations

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