Low salinity and sediment stress on sea urchin Evechinus chloroticus larvae has latent effects on juvenile performance

2019 ◽  
Vol 619 ◽  
pp. 85-96 ◽  
Author(s):  
A Glockner-Fagetti ◽  
NE Phillips
Keyword(s):  
Sea Urchin ◽  
Low Salinity ◽  
Latent Effects

scholarly journals Direct and latent effects of ocean acidification on the transition of a sea urchin from planktonic larva to benthic juvenile

2021 ◽  
Author(s):  
Narimane Dorey ◽  
Emanuela Butera ◽  
Nadjejda Espinel-Velasco ◽  
Sam Dupont
Keyword(s):  
Life History ◽  
Ocean Acidification ◽  
Sea Urchin ◽  
Indirect Effects ◽  
Strongylocentrotus Droebachiensis ◽  
Energetic Cost ◽  
Continuous Exposure ◽  
Direct And Indirect Effects ◽  
Life History Stages ◽  
Latent Effects

Ongoing ocean acidification (OA) is expected to affect marine organisms and ecosystems. While sea urchins can survive a wide range of pH, this comes at a high energetic cost, and early life stages are particularly vulnerable. Information on how OA affects transitions between life-history stages is scarce. We evaluated the direct and indirect effects of pH (pHT 8.0, 7.6 and 7.2) on the development and transition between life-history stages of the sea urchin Strongylocentrotus droebachiensis, from fertilization to early juvenile. Continuous exposure to low pH negatively affected larval mortality and growth. At pH 7.2, formation of the rudiment (the primordial juvenile) was delayed by two days. Larvae raised at pH 8.0 and transferred to 7.2 after competency had mortality rates five to six times lower than those kept at 8.0, indicating that pH also has a direct effect on older, competent larvae. Latent effects were visible on the larvae raised at pH 7.6: they were more successful in settling (45%) and metamorphosing (30%) than larvae raised at 8.0 (17 and 1% respectively). These direct and indirect effects of OA on settlement and metamorphosis have important implications for population survival.

scholarly journals Effects of metal toxicity on the early life stages of the sea urchin Evechinus chloroticus

2021 ◽  
Author(s):  
◽  
Agnes Rouchon
Keyword(s):  
Early Life ◽  
Metal Toxicity ◽  
Chronic Exposure ◽  
Multiple Stressors ◽  
Life Stages ◽  
Early Life Stages ◽  
River Plumes ◽  
Low Salinity ◽  
Latent Effects ◽  
Algal Diet

<p>Metals are a common source of pollution in coastal waters, and have long been recognised as a major concern for many marine species, especially their early life stages. Although effects have been examined using standard toxicity assays, the impact of metals in more complex and realistic exposure regimes is still poorly known, in particular with regards to latent effects across multiple life stages and the interaction of multiple stressors. In this thesis, the effects of metals were investigated for multiple life stages of the endemic New Zealand sea urchin Evechinus chloroticus.  Standard short-term bioassays were performed on the early life stage of E. chloroticus and also the endemic abalone Haliotis iris, for comparison. These assays evaluated the toxicity of three major pollutants (copper, lead and zinc) alone and in combination, on these species. Embryos of both species were highly vulnerable to copper (EC50s: 5.4 and 3.4 µg/L respectively for E. chloroticus and H. iris) and zinc (27.7 and 13.1 µg/L) but relatively tolerant to lead (52.2 and 775 µg/L), and there was no evidence of synergistic effects of metal mixtures.  The latent effects of copper across two life stages in E. chloroticus, larval and juvenile, were investigated with laboratory experiments using realistic scenarios of low copper concentration, short pulses of exposure and examining exposure through dietary intake as well as waterborne exposure. Strong latent and carry-over effects were observed even at low concentration and short exposure time. For example, individuals exposed as larvae to 10.4 µg/L Cu for two days developed normally during the larval stage but had strongly impaired subsequent growth, with average body size decreasing by 24% in the 25 d following settlement. Moreover, juveniles previously exposed to copper as larvae were less resistant to a subsequent exposure, with up to four times higher mortality. Latent effects were especially important when copper was present in the diet rather than dissolved in water. For example, E. chloroticus larvae exposed to 2.3 µg/L Cu in water and fed with an algal diet cultured in the same concentration had a settlement success three times lower than those exposed only to waterborne copper. Furthermore, a short pulse exposure (4 days) to copper in the algal diet was generally more toxic than chronic exposure, showing that a short-lived bloom of contaminated phytoplankton may have a more severe impact on zooplankton than chronic pollution.  Because metal discharge in coastal water is generally associated with freshwater (e.g. storm water or river plumes), the toxicity of copper was evaluated in both normal and low salinity seawater. Low salinity (24 ppt) increased copper toxicity in E. chloroticus larvae under chronic exposure to high levels (15 µg/L; 43% and 80% lower survival and normal development rate, respectively) but not under a single pulse exposure (4 days) to low concentration (5 µg/L). This highlights the importance of using realistic exposure in laboratory assays.  Finally, the effect of copper on adult E. chloroticus and in particular on their fertilisation success was evaluated. Strong sublethal effects were observed after exposure to 50 µg/L Cu for two weeks including spawning impairment (especially in females) and elevated copper burden in gonads (25-times higher than control animals). However, the fertilisation success of successfully spawning males was not affected. The prevalence of local metal contamination was also measured at the mouth of local river plumes and in E. chloroticus gonads at sites expected to vary in likely exposure to pollution. Copper levels exceeding water quality criteria were found in two instances in coastal agricultural runoff (Makara stream). Other metals were within water quality cirteria in all samplings. Adult E. chloroticus had an elevated copper burden in gonads in an urban site compared to a control site (0.77 µg/g vs. 0.27 µg/g).  In total, this research demonstrates the need for considering toxic effects across multiple life stages and using realistic exposure regimes (e.g. timing, concentration, multiple stressors) to better understand the likely impact of metal pollution on marine populations. It also provides the first measure of metal toxicity on early life stages of an endemic species of cultural and commercial importance in New Zealand.</p>

scholarly journals Effects of metal toxicity on the early life stages of the sea urchin Evechinus chloroticus

2021 ◽  
Author(s):  
◽  
Agnes Rouchon
Keyword(s):  
Early Life ◽  
Metal Toxicity ◽  
Chronic Exposure ◽  
Multiple Stressors ◽  
Life Stages ◽  
Early Life Stages ◽  
River Plumes ◽  
Low Salinity ◽  
Latent Effects ◽  
Algal Diet

<p>Metals are a common source of pollution in coastal waters, and have long been recognised as a major concern for many marine species, especially their early life stages. Although effects have been examined using standard toxicity assays, the impact of metals in more complex and realistic exposure regimes is still poorly known, in particular with regards to latent effects across multiple life stages and the interaction of multiple stressors. In this thesis, the effects of metals were investigated for multiple life stages of the endemic New Zealand sea urchin Evechinus chloroticus.  Standard short-term bioassays were performed on the early life stage of E. chloroticus and also the endemic abalone Haliotis iris, for comparison. These assays evaluated the toxicity of three major pollutants (copper, lead and zinc) alone and in combination, on these species. Embryos of both species were highly vulnerable to copper (EC50s: 5.4 and 3.4 µg/L respectively for E. chloroticus and H. iris) and zinc (27.7 and 13.1 µg/L) but relatively tolerant to lead (52.2 and 775 µg/L), and there was no evidence of synergistic effects of metal mixtures.  The latent effects of copper across two life stages in E. chloroticus, larval and juvenile, were investigated with laboratory experiments using realistic scenarios of low copper concentration, short pulses of exposure and examining exposure through dietary intake as well as waterborne exposure. Strong latent and carry-over effects were observed even at low concentration and short exposure time. For example, individuals exposed as larvae to 10.4 µg/L Cu for two days developed normally during the larval stage but had strongly impaired subsequent growth, with average body size decreasing by 24% in the 25 d following settlement. Moreover, juveniles previously exposed to copper as larvae were less resistant to a subsequent exposure, with up to four times higher mortality. Latent effects were especially important when copper was present in the diet rather than dissolved in water. For example, E. chloroticus larvae exposed to 2.3 µg/L Cu in water and fed with an algal diet cultured in the same concentration had a settlement success three times lower than those exposed only to waterborne copper. Furthermore, a short pulse exposure (4 days) to copper in the algal diet was generally more toxic than chronic exposure, showing that a short-lived bloom of contaminated phytoplankton may have a more severe impact on zooplankton than chronic pollution.  Because metal discharge in coastal water is generally associated with freshwater (e.g. storm water or river plumes), the toxicity of copper was evaluated in both normal and low salinity seawater. Low salinity (24 ppt) increased copper toxicity in E. chloroticus larvae under chronic exposure to high levels (15 µg/L; 43% and 80% lower survival and normal development rate, respectively) but not under a single pulse exposure (4 days) to low concentration (5 µg/L). This highlights the importance of using realistic exposure in laboratory assays.  Finally, the effect of copper on adult E. chloroticus and in particular on their fertilisation success was evaluated. Strong sublethal effects were observed after exposure to 50 µg/L Cu for two weeks including spawning impairment (especially in females) and elevated copper burden in gonads (25-times higher than control animals). However, the fertilisation success of successfully spawning males was not affected. The prevalence of local metal contamination was also measured at the mouth of local river plumes and in E. chloroticus gonads at sites expected to vary in likely exposure to pollution. Copper levels exceeding water quality criteria were found in two instances in coastal agricultural runoff (Makara stream). Other metals were within water quality cirteria in all samplings. Adult E. chloroticus had an elevated copper burden in gonads in an urban site compared to a control site (0.77 µg/g vs. 0.27 µg/g).  In total, this research demonstrates the need for considering toxic effects across multiple life stages and using realistic exposure regimes (e.g. timing, concentration, multiple stressors) to better understand the likely impact of metal pollution on marine populations. It also provides the first measure of metal toxicity on early life stages of an endemic species of cultural and commercial importance in New Zealand.</p>

Immunogold and immunoblot studies on a cell surface protein found in primary mesenchyme cells and in the cortical secretory vesicles of the sea urchin egg

1987 ◽  
Vol 45 ◽  
pp. 832-833
Author(s):  
G.L. Decker ◽  
M.C. Valdizan
Keyword(s):  
Cell Surface ◽  
Sea Urchin ◽  
Surface Protein ◽  
Egg Cell ◽  
Secretory Vesicles ◽  
Cell Surface Protein ◽  
Surface Complexes ◽  
Mesenchyme Cells ◽  
Lowicryl K4m ◽  
Primary Mesenchyme Cells

A monoclonal antibody designated MAb 1223 has been used to show that primary mesenchyme cells of the sea urchin embryo express a 130-kDa cell surface protein that may be directly involved in Ca2+ uptake required for growth of skeletal spicules. Other studies from this laboratory have shown that the 1223 antigen, although in relatively low abundance, is also expressed on the cell surfaces of unfertilized eggs and on the majority of blastomeres formed prior to differentiation of the primary mesenchyme cells.We have studied the distribution of 1223 antigen in S. purpuratus eggs and embryos and in isolated egg cell surface complexes that contain the cortical secretory vesicles. Specimens were fixed in 1.0% paraformaldehyde and 1.0% glutaraldehyde and embedded in Lowicryl K4M as previously reported. Colloidal gold (8nm diameter) was prepared by the method of Mulpfordt.

The extracellular matrix of echinoderm and amphibian eggs: Visualization in quick-frozen, deep-etched, and rotary-shadowed specimens

1990 ◽  
Vol 48 (3) ◽  
pp. 60-61
Author(s):  
Barry Bonnell ◽  
Carolyn Larabell ◽  
Douglas Chandler
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Sea Urchin ◽  
Crystalline Structure ◽  
Cortical Granule ◽  
Two Dimensional ◽  
Small Peptides ◽  
Deep Etching ◽  
Quick Freezing ◽  
Acrosomal Reaction

Eggs of many species including those of echinoderms, amphibians and mammals exhibit an extensive extracellular matrix (ECM) that is important both in the reception of sperm and in providing a block to polyspermy after fertilization.In sea urchin eggs there are two distinctive coats, the vitelline layer which contains glycoprotein sperm receptors and the jelly layer that contains fucose sulfate glycoconjugates which trigger the acrosomal reaction and small peptides which act as chemoattractants for sperm. The vitelline layer (VL), as visualized by quick-freezing, deep-etching, and rotary-shadowing (QFDE-RS), is a fishnet-like structure, anchored to the plasma membrane by short posts. Orbiting above the VL are horizontal filaments which are thought to anchor the thicker jelly layer to the egg. Upon fertilization, the VL elevates and is transformed by cortical granule secretions into the fertilization envelope (FE). The rounded casts of microvilli in the VL are transformed into angular peaks and the envelope becomes coated inside and out with sheets of paracrystalline protein having a quasi-two dimensional crystalline structure.

Introductory Remarks

1980 ◽  
Vol 38 ◽  
pp. 598-599
Author(s):  
H. Mohri
Keyword(s):  
Muscle Contraction ◽  
Experimental Evidence ◽  
Sea Urchin ◽  
Constant Length ◽  
Thin Filaments ◽  
Bridge Formation ◽  
Thick Filaments ◽  
Sliding Mechanism ◽  
Radial Spokes ◽  
Cilia And Flagella

In 1959, Afzelius observed the presence of two rows of arms projecting from each outer doublet microtubule of the so-called 9 + 2 pattern of cilia and flagella, and suggested a possibility that the outer doublet microtubules slide with respect to each other with the aid of these arms during ciliary and flagellar movement. The identification of the arms as an ATPase, dynein, by Gibbons (1963)strengthened this hypothesis, since the ATPase-bearing heads of myosin molecules projecting from the thick filaments pull the thin filaments by cross-bridge formation during muscle contraction. The first experimental evidence for the sliding mechanism in cilia and flagella was obtained by examining the tip patterns of molluscan gill cilia by Satir (1965) who observed constant length of the microtubules during ciliary bending. Further evidence for the sliding-tubule mechanism was given by Summers and Gibbons (1971), using trypsin-treated axonemal fragments of sea urchin spermatozoa. Upon the addition of ATP, the outer doublets telescoped out from these fragments and the total length reached up to seven or more times that of the original fragment. Thus, the arms on a certain doublet microtubule can walk along the adjacent doublet when the doublet microtubules are disconnected by digestion of the interdoublet links which connect them with each other, or the radial spokes which connect them with the central pair-central sheath complex as illustrated in Fig. 1. On the basis of these pioneer works, the sliding-tubule mechanism has been established as one of the basic mechanisms for ciliary and flagellar movement.

The Organization of Actin Filaments in the Stereocilia of the Bird Cochlea

1980 ◽  
Vol 38 ◽  
pp. 554-555
Author(s):  
E.J. Battles ◽  
D. DeRosier ◽  
J.C. Saunders ◽  
L.G. Tilney
Keyword(s):  
Hair Cell ◽  
Diffraction Pattern ◽  
Sea Urchin ◽  
Actin Filaments ◽  
Optical Diffraction ◽  
Dense Material ◽  
Apical Surface ◽  
Structural Rigidity ◽  
High Degree ◽  
Degree Of Order

Extending from the apical surface of each hair cell of the chick cochlea are from 75 to 200 microvilli or stereocllia and one true cllium, the kinocilium. The stereocllia are arranged in rows of progressively increasing length (Fig. 1). Within each tapering sterocilium is a bundle of actin filaments with over 900 filaments near the tip yet only approximately 25 at the base where filaments are enmeshed in a dense material (Fig. 1); from here some of the filaments enter the apical surface of the cell (cuticular plate) as a rootlet. Examination of longitudinal sections of the stereocilia (Fig. 2) show that the filaments are aligned parallel to each other and show considerable order. Examination of an optical diffraction pattern of this bundle (Fig. 4) reveal that the actin filaments are packed such that the crossover points of adjacent actin filaments are inregister. A prominent reflection at 125Å−1 demonstrates that the filaments are cjossbridged by a macromolecular bridge situated at an average of 125Å−1 intervals (Fig. 4) in transverse sections the filaments appear hexagonally packed although there are regions where the filaments are less ordered (Fig. 3). In images processed in the computer to remove, noise and enhance detail periodic nature of the bridge can be clearly seen (see arrows Fig. 5). This image resembles that of an actin paracrystal formed from sea urchin extract composed of bundles of actin filaments crossbridged by a second protein. Thus the actin filaments in the bird stereocilia by being cross-bridged and packed with a high degree of order and produces a structure with considerable structural rigidity. Embryos were studied at various stages in development in an attempt to determine how the stereocilia form and how does the actin packing develops. These stages will be discussed.

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