Polyphenols extracts from Didymosphenia geminata (Lyngbye) Schmidt altered the motility and viability of Daphnia magna

Polyphenols Extracts From Didymosphenia Geminata (Lyngbye) Schmidt Altered the Motility and Viability of Daphnia Magna

10.21203/rs.3.rs-186618/v1 ◽

2021 ◽

Author(s):

Pamela Olivares-Ferretti ◽

Viviana Chavez ◽

Klaudia Hernandez ◽

Matías Peredo-Parada ◽

Jorge Parodi

Keyword(s):

River Water ◽

Daphnia Magna ◽

Aquatic Species ◽

Didymosphenia Geminata ◽

Controlled Conditions

Abstract The invasive diatom Didymosphenia geminata (Lyngbye) Schmidt, D. geminata has invaded the austral zone of Chile, causing significant ecological, scientific and societal concerns. We aimed to evaluate the viability and motility Daphnia magna (D. magna), as a biosensor for effects of D. geminata. Toxicity assays were performed in dilutions of river water alone (V/V dilution) and in river water contaminated with D. geminata (V/V dilution) or polyphenols extracted from D. geminata under controlled conditions and different time (acute 30 min and 7 hrs). Our results indicated that D. magna was sensitive to increasing concentrations of D. geminata extracts. We observed a 50% (IC50) viability reduction after 24 h of exposure to a 0.023 V/V dilution and the same value when using polyphenols from D. geminata; additionally, this treatment further reduced the motility capacity by 50% after 72 h. The D. magna organisms were acutely responsive, showing a 50% reduction in frequency at 15 min. We conclude that D. magna is sensitive to polyphenols produced by D. geminata in rivers, suggesting potential chronic toxic consequences on several aquatic species following exposure to these diatom substances.

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Membrane-bound vesicles associated with the microvilli in the midgut of the freshwater microcrustacean, Daphnia magna

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100076135 ◽

1983 ◽

Vol 41 ◽

pp. 480-481

Author(s):

Patricia L. Jansma

Keyword(s):

Daphnia Magna ◽

Intestinal Epithelial Cells ◽

Uranyl Acetate ◽

Intestinal Epithelial ◽

Chlamydomonas Reinhardii ◽

Thin Sections ◽

Saturated Water ◽

Cacodylate Buffer ◽

Membrane Bound ◽

Ethanol Series

The presence of the membrane bound vesicles or blebs on the intestinal epithelial cells has been demonstrated in a variety of vertebrates such as chicks, piglets, hamsters, and humans. The only invertebrates shown to have these microvillar blebs are two species of f1ies. While investigating the digestive processes of the freshwater microcrustacean, Daphnia magna, the presence of these microvillar blebs was noticed.Daphnia magna fed in a suspension of axenically grown green alga, Chlamydomonas reinhardii for one hour were narcotized with CO2 saturated water. The intestinal tracts were excised in 2% glutaraldehyde in 0.2 M cacodyl ate buffer and then placed in fresh 2% glutaraldehyde for one hour. After rinsing in 0.1 M cacodylate buffer, the sample was postfixed in 2% OsO4, dehydrated with a graded ethanol series, infiltrated and embedded with Epon-Araldite. Thin sections were stained with uranyl acetate and Reynolds lead citrate before viewing with the Philips EM 200.

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Computer Reconstruction of the Cellular Architecture of the Daphnia Magna Optic Ganglion

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100115043 ◽

1975 ◽

Vol 33 ◽

pp. 284-285

Author(s):

E. R. Macagno ◽

C. Levinthal

Keyword(s):

Daphnia Magna ◽

Genetic Background ◽

Compound Eye ◽

Synaptic Connectivity ◽

Serial Sections ◽

Cross Sectional ◽

Small Crustacean ◽

Optic Ganglion ◽

Structural Invariance ◽

High Degree

The optic ganglion of Daphnia Magna, a small crustacean that reproduces parthenogenetically contains about three hundred neurons: 110 neurons in the Lamina or anterior region and about 190 neurons in the Medulla or posterior region. The ganglion lies in the midplane of the organism and shows a high degree of left-right symmetry in its structures. The Lamina neurons form the first projection of the visual output from 176 retinula cells in the compound eye. In order to answer questions about structural invariance under constant genetic background, we have begun to reconstruct in detail the morphology and synaptic connectivity of various neurons in this ganglion from electron micrographs of serial sections (1). The ganglion is sectioned in a dorso-ventra1 direction so as to minimize the cross-sectional area photographed in each section. This area is about 60 μm x 120 μm, and hence most of the ganglion fit in a single 70 mm micrograph at the lowest magnification (685x) available on our Zeiss EM9-S.

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