Daphnia magna Gut Specific Trancriptomic Responses to Feeding Inhibiting Chemicals and Food Limitation

2021 ◽  
Author(s):  
Bruno Campos ◽  
Benjamín Piña ◽  
Carlos Barata
Keyword(s):  
Daphnia Magna ◽  
Food Limitation

scholarly journals Tissue translocation, multigenerational and population effects of microplastics in Daphnia magna

2021 ◽  
Author(s):  
◽  
Schür Christoph
Keyword(s):  
Water Column ◽  
Daphnia Magna ◽  
Food Limitation ◽  
Freshwater Ecosystems ◽  
Plastic Waste ◽  
Lipid Storage ◽  
Fluorescence Signal ◽  
Naturally Occurring ◽  
Plastic Materials ◽  
Population Effects

The last century saw the widespread adoption of plastic materials throughout nearly every aspect of our lives. Plastics are synthetic polymers that are made up of monomer chains. The properties of the monomer in conjunction with chemical additives allow plastics to have a sheer endless variety of features and use cases. They are cheap, lightweight, and extremely durable. Plastic materials are often engineered for single-use and in conjunction with high production volumes and insufficient waste management and recycling across the globe, this leads to a large number of plastics entering the environment. Marine ecosystems are considered sinks. However, freshwater ecosystems as entry pathways are highly affected by plastic waste as well. Throughout the past decade, the impact of plastic waste on human and environmental health has received a lot of attention from the ecotoxicological community as well as the public. Small plastic fragments (< 1 mm called microplastics) are a large part of this emerging field of research. Within this, the water flea Daphnia magna is probably the most common organism that is used to assess microplastics toxicity. As a filter-feeding organism, it indiscriminately ingests particles from the water column and is thus highly susceptible to microplastics. For this thesis, we identified some gaps in the available data on the ecotoxicity of microplastics to daphnids. To illuminate some of those gaps the present thesis was aimed at five main aspects: (1) Tissue translocation of spherical microplastics in Daphnia magna (2) Investigation of the toxicity of irregularly shaped microplastics (3) Multigenerational and population effects of microplastics (4) Comparison of the toxicity of microplastics and natural particles (5) Effects of particle-aging on microplastics toxicity The thesis is comprised of three peer-reviewed articles and one so-far unpublished study as “additional results”. The first study was aimed at understanding tissue translocation of spherical microplastics to lipid storage droplets of daphnids. The crossing of biological membranes is discussed as a prerequisite to eliciting tissue damage and an inflammatory response. Previously, researchers reported the translocation of fluorescently labeled spherical microplastics to lipid storage droplets of daphnids, even though no plausible biological mechanism to explain this occurrence. Therefore, in order to learn more about this process and potentially illuminate the mechanism we replicated the study. We were able to observe a fluorescence signal inside the lipid droplets only after increasing the exposure concentrations. Nonetheless, it appeared to be independent of particles. This led to the hypothesis, that the lipophilic fluorescent dye uncoupled from the particles and subsequently accumulated in lipid storage droplets. The hypothesis was further confirmed through an additional experiment with a silicone-based passive sampling device showing that the fluorescence occurred both independent of particles and digestive processes. Accordingly, we concluded that the reported findings were a microscopic artifact caused by the uncoupling of the dye from the particles. Therefore, a fluorescence signal alone is not a sufficient proxy to assume that particles have translocated. It needs to be coupled with additional methods to ensure that the observation is indeed caused by the translocation of particles. It is still unclear whether the toxicity profile of microplastics is different from that of naturally occurring particles or if they are “just another particle”, as there are innumerable amounts in the natural environment surrounding an organism. The goal of the second study was to compare the toxicity of irregularly shaped polystyrene microplastics to that of the natural particle kaolin. The environment is full of natural non-food particles that daphnids ingest more or less indiscriminately and therefore are well adapted to deal with. Daphnids have a short generation time and usually experience food limitation in nature. Therefore, short-term studies only looking at acute toxicity with ad libitum food availability are not representative of the exposure scenario in nature. For a more realistic scenario, we, therefore, used a four-generation multigenerational design under food limitation to investigate how effects translate from one generation to the next. We observed concentration-dependent effects of microplastics but not of natural particles on mortality, reproduction, and growth. Some of the effects increased from generation to generation, leading to the extinction of two treatment groups. Here, microplastics were more toxic than natural particles. At least part of this difference can be explained by physical properties leading to the quick sedimentation of the kaolin, while microplastics remained in the water column. Nonetheless, buoyancy and sedimentation would also affect exposure in the environment and are likely different for most microplastics than for most naturally occurring particle types. ...

Estimating food availability for larval dragonflies: a cautionary note

1986 ◽  
Vol 64 (4) ◽  
pp. 1036-1038 ◽  
Author(s):  
Robert L. Baker
Keyword(s):  
Daphnia Magna ◽  
Food Availability ◽  
Food Limitation ◽  
Food Type ◽  
Cautionary Note ◽  
Fecal Pellets ◽  
Ad Libitum ◽  
Ischnura Verticalis

Fecal pellets produced by larvae of Enallagma ebrium and Ischnura verticalis given ad libitum feedings of enchytraeid worms were heavier than pellets produced by larvae given ad libitum feedings of Daphnia magna. Dependence of pellet weight on food type has marked implications for indices of food limitation for larval dragonflies.

INFLUENCE OF FOOD LIMITATION ON THE EFFECTS OF FENVALERATE PULSE EXPOSURE ON THE LIFE HISTORY AND POPULATION GROWTH RATE OF DAPHNIA MAGNA

2005 ◽  
Vol 24 (9) ◽  
pp. 2254 ◽  
Author(s):  
Barry J. Pieters ◽  
Albrecht Paschke ◽  
Sebastián Reynaldi ◽  
Michiel H.S. Kraak ◽  
Wim Admiraal ◽  
...  
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Population Growth ◽  
Daphnia Magna ◽  
Population Growth Rate ◽  
Food Limitation ◽  
Pulse Exposure ◽  
Influence Of Food

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

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.

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

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.

Effects of food limitation and emigration on self-thinning in experimental minnow cohorts

2000 ◽  
Vol 69 (6) ◽  
pp. 927-934 ◽  
Author(s):  
J. B. Dunham ◽  
B. R. Dickerson ◽  
E. Beever ◽  
R. D. Duncan ◽  
G. L. Vinyard
Keyword(s):  
Food Limitation

Mise en évidence des effets sublétaux sur des populations de daphnies (Daphnia magna)

1981 ◽  
Vol 12 (1) ◽  
pp. 63-79
Author(s):  
R. Cabridenc ◽  
Bui Thi ◽  
H. Lepailleur
Keyword(s):  
Daphnia Magna

Biological Effects of the Combined Chronic Action of 90Sr and Pb2+ on Daphnia Magna Straus

2002 ◽  
Vol 38 (4) ◽  
pp. 11
Author(s):  
M. G. Mardarevich ◽  
D. I. Gudkov ◽  
L. S. Kipnis ◽  
V. V. Belyaev
Keyword(s):  
Daphnia Magna ◽  
Biological Effects

Toxic Action of Petroleum and Oil Processing Products on Daphnia magna Straus

2002 ◽  
Vol 38 (1) ◽  
pp. 11
Author(s):  
A. A. Ratushnyak ◽  
M. G. Andreyeva ◽  
V. Z. Latypova ◽  
L. G. Garipova
Keyword(s):  
Daphnia Magna ◽  
Toxic Action ◽  
Oil Processing
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