Transcriptomic response of Daphnia magna to nitrogen‐ or phosphorus‐limited diet

Chronic toxicity evaluation of the flame retardant tris (2-butoxyethyl) phosphate (TBOEP) using Daphnia magna transcriptomic response

Chemosphere ◽

10.1016/j.chemosphere.2015.03.028 ◽

2015 ◽

Vol 132 ◽

pp. 159-165 ◽

Cited By ~ 18

Author(s):

Maeva Giraudo ◽

Mélanie Douville ◽

Magali Houde

Keyword(s):

Flame Retardant ◽

Daphnia Magna ◽

Chronic Toxicity ◽

Toxicity Evaluation ◽

Transcriptomic Response

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Transcriptomic Response of Daphnia Magna to Nitrogen or Phosphorus Limited Diet

10.21203/rs.3.rs-70065/v1 ◽

2020 ◽

Author(s):

Zhimeng Xu ◽

Yingdong Li ◽

Meng Li ◽

Hongbin Liu

Keyword(s):

Growth Rate ◽

Daphnia Magna ◽

Molecular Mechanisms ◽

Cell Structure ◽

Nutrient Stress ◽

The Body ◽

Reproduction Rate ◽

Transcriptomic Response ◽

N Limitation ◽

P Limitation

Abstract Background: Effects of nutrient-imbalanced diet on the growth and fitness of zooplankton were widely reported. However, little is known about the molecular mechanisms driving the physiological changes of zooplankton under nutrient stress.Results: In this study, we investigated the physiological fitness and transcriptomic response of Daphnia magna when exposed to nitrogen (N)-limited or phosphorus (P)-limited algal diet (Chlamydomonas reinhardtii) compared to regular algae (N and P saturated). D. magna showed higher ingestion rates and over expression of genes encoding digestive enzymes when fed with either N-limited or P-limited algae, reflecting the compensatory feeding. Under P-limitation, both growth rate and reproduction rate of D. magna were greatly reduced, which could be attributed to the downregulated genes within the pathways of cell cycle and DNA replication. Growth rate of D. magna under N-limitation was similar to normal group, which could be explained by the high methylation level (by degradation of methionine) supporting the body development.Conclusions: Phenotypic changes of D. magna under nutrient stress were explained by gene and pathway regulations from transcriptome data. Generally, D. magna invested more on growth under N-limitation but kept maintenance (e.g. cell structure and defense to external stress) in priority under P-limitation. Post-translational modifications (e.g. methylation and protein folding) were important for D. magna to deal with nutrient constrains. This study reveals the fundamental mechanisms of zooplankton in dealing with elemental imbalanced diet and shed light on the transfer of energy and nutrient in aquatic ecosystems.

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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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