The Fertilization Reaction in the Sea-Urchin

1. The reactions of sea-urchin eggs (Psammechinus miliaris) to high concentrations of homologous spermatozoa have been investigated by a new method. 2. The method was to inseminate eggs with high concentrations of spermatozoa (108/ml.), which ensured that all eggs were fertilized for the first time at the beginning of the experiment; and then functionally to separate the eggs and spermatozoa at known times after the original insemination. 3. The proportion of polyspermic eggs in the suspension rises from zero at t=0 to a constant value at a time T, which is the conduction time of the block to polyspermy. In fourteen experiments on eggs from different sea-urchins, the estimated values of T were 17, 69, 72, 74, 94, 85, 26, 60, 31, 91, 85, 34, 75 and 67 sec. (arithmetic mean 63 sec.). The standard errors of the estimates of T, which are tabulated in the text, ranged from 5 to 15 sec. 4. These results confirm previous experiments which strongly suggested that the conduction time of the block to polyspermy was of the order of seconds; these earlier experiments were incompatible with a block to polyspermy lasting a fraction of a second. 5. At the same time experiments in this paper made it possible to estimate the fertilization parameter or sperm-egg interaction rate α, during the conduction of the block to polyspermy, and to compare it with the pre-fertilization α. In a given sperm suspension, α is a measure of the receptivity of the egg surface to spermatozoa. During the conduction of the block to polyspermy α was found to be markedly lower (1/20) than in unfertilized eggs. 6. This suggests that at fertilization there is a fast but incomplete block to polyspermy, whose conduction time may be 1 sec. or less. This is followed by the slower block which finally makes the egg impermeable to spermatozoa. This also confirms previous observations on the small incidence of polyspermy at normal sperm densities, which is not consistent with the concept of a slow block to polyspermy.

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The Fertilization Reaction in the Sea-Urchin

Journal of Experimental Biology ◽

10.1242/jeb.28.3.403 ◽

1951 ◽

Vol 28 (3) ◽

pp. 403-416 ◽

Cited By ~ 1

Author(s):

LORD ROTHSCHILD ◽

M. M. SWANN

Keyword(s):

Sea Urchin ◽

Inverse Relationship ◽

Physical Nature ◽

Conduction Time ◽

The Past ◽

Sperm Density ◽

Psammechinus Miliaris ◽

Sperm Suspension ◽

Source Of Error ◽

Kinetic Treatment

1. Unfertilized eggs of the sea-urchin (Psammechinus miliaris) were left for known but varying times in contact with homologous sperm suspensions containing known numbers of spermatozoa. Counts were made of the numbers of fertilized and unfertilized eggs at times ranging from 0 to 300 sec. after mixing. 2. If spermatozoa are considered as particles moving in random directions, the frequency of sperm-egg collisions can be calculated if the density and mean speed of the sperm suspension are known. 3. The information in (1) and (2) enables an estimate to be made of the probability of a successful sperm-egg collision. 4. The estimated probability of a successful collision, p, varies with sperm density, d. At the lowest density used, 7.44x104/ml., p was found to be 0.226. At the highest density, 9.62/106/ml., p was about 0.011. The inverse relationship between p and d may be due to sperm-sperm interactions of a physical nature. 5. The presence of jelly round the eggs increases p. This disposes of the possibility, raised in the past, that egg jelly may have an adverse effect on the fertilizing capacity of homologous spermatozoa under normal conditions of fertilization. 6. The technique of subjecting eggs to a pre-determined number of collisions facilitates investigation of the conduction time of the block to polyspermy. Preliminary experiments suggest that the conduction time may be of the order of seconds rather than fractions of a second. 7. Sources of error arising from the ‘kinetic’ treatment of sperm suspensions are discussed in detail. One source of error concerns the alleged chemotaxis of spermatozoa towards eggs and egg secretions. No chemotaxis was observed.

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Combined Effects of Diatom-Derived Oxylipins on the Sea Urchin Paracentrotus lividus

International Journal of Molecular Sciences ◽

10.3390/ijms21030719 ◽

2020 ◽

Vol 21 (3) ◽

pp. 719 ◽

Cited By ~ 1

Author(s):

Roberta Esposito ◽

Nadia Ruocco ◽

Luisa Albarano ◽

Adrianna Ianora ◽

Loredana Manfra ◽

...

Keyword(s):

Stress Response ◽

Sea Urchin ◽

Sea Urchins ◽

Cell Damage ◽

Harmful Effect ◽

Paracentrotus Lividus ◽

Combined Effects ◽

New Genes ◽

Polyunsaturated Aldehydes ◽

First Time

Oxylipins are diatom-derived secondary metabolites, deriving from the oxidation of polyunsatured fatty acids that are released from cell membranes after cell damage or senescence of these single-celled algae. Previous results revealed harmful toxic effects of polyunsaturated aldehydes (PUAs) and hydroxyacids (HEPEs) on sea urchin Paracentrotus lividus embryonic development by testing individual compounds and mixtures of the same chemical group. Here, we investigated the combined effects of these compounds on sea urchin development at the morphological and molecular level for the first time. Our results demonstrated that oxylipin mixtures had stronger effects on sea urchin embryos compared with individual compounds, confirming that PUAs induce malformations and HEPEs cause developmental delay. This harmful effect was also confirmed by molecular analysis. Twelve new genes, involved in stress response and embryonic developmental processes, were isolated from the sea urchin P. lividus; these genes were found to be functionally interconnected with 11 genes already identified as a stress response of P. lividus embryos to single oxylipins. The expression levels of most of the analyzed genes targeted by oxylipin mixtures were involved in stress, skeletogenesis, development/differentiation, and detoxification processes. This work has important ecological implications, considering that PUAs and HEPEs represent the most abundant oxylipins in bloom-forming diatoms, opening new perspectives in understanding the molecular pathways activated by sea urchins exposed to diatom oxylipins.

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Molecular and Morphological Toxicity of Diatom-Derived Hydroxyacid Mixtures to Sea Urchin Paracentrotus lividus Embryos

Marine Drugs ◽

10.3390/md17030144 ◽

2019 ◽

Vol 17 (3) ◽

pp. 144 ◽

Cited By ~ 4

Author(s):

Luisa Albarano ◽

Nadia Ruocco ◽

Adrianna Ianora ◽

Giovanni Libralato ◽

Loredana Manfra ◽

...

Keyword(s):

Fatty Acids ◽

Sea Urchin ◽

Marine Invertebrates ◽

Molecular Level ◽

Sea Urchins ◽

Synergistic Effects ◽

Paracentrotus Lividus ◽

Diatom Blooms ◽

Polyunsaturated Aldehydes ◽

First Time

Oxylipins such as polyunsaturated aldehydes (PUAs) and hydroxyacids (HEPEs) are signaling molecules derived from the oxidation of polyunsaturated fatty acids. They are common in diatoms that constitute a major group of microalgae in freshwater and oceanic ecosystems. Although HEPEs represent the most common oxylipins produced by diatoms, little information is available on their effects on marine invertebrates, and most of the information has been obtained by testing individual HEPEs. Our previous studies reported that four hydroxyacids, i.e., 5-, 9-, 11-, and 15-HEPE, were able to induce malformations and a marked developmental delay in sea urchin Paracentrotus lividus embryos, which had not been reported for other oxylipins. Here, we tested a mixture of 5-, 9-, 11-, and 15-HEPE at different concentrations for the first time. The results showed that mixtures of HEPEs have synergistic effects that are much more severe compared to those of individual HEPEs: The HEPE mixtures induced malformations in sea urchin embryos at lower concentrations. Increasing HEPE mixture concentrations induced a marked increase in the number of delayed embryos, until all embryos were delayed at the highest concentration tested. At the molecular level, the HEPE mixtures induced variations in the expression of 50 genes involved in different functional processes, mainly down-regulating these genes at the earliest stages of embryonic development. These findings are ecologically significant, considering that during diatom blooms, sea urchins could accumulate HEPEs in concentrations comparable to those tested in the present study.

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Interaction among sea urchins in response to food cues

Scientific Reports ◽

10.1038/s41598-021-89471-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jiangnan Sun ◽

Zihe Zhao ◽

Chong Zhao ◽

Yushi Yu ◽

Peng Ding ◽

...

Keyword(s):

Sea Urchin ◽

Sea Urchins ◽

Control Period ◽

Dispersal Distance ◽

Movement Speed ◽

Movement Direction ◽

Food Cues ◽

Significant Difference ◽

Potential Interactions ◽

First Time

AbstractInteraction among sea urchins remains largely uninvestigated, although the aggregation of sea urchins is common. In the present study, 1, 15 and 30 sea urchins Strongylocentrotus intermedius (11.06 ± 0.99 mm in test diameter) were placed in a 1 m2 circular tank, respectively. Movement behaviors were recorded for 12 min to investigate potential interactions among sea urchins. After the 12-min control period, we added food cues into the tank and recorded the changes in sea urchins’ behaviors. For the first time, we here quantified the interactions among sea urchins in laboratory and found that the interactions varied with food cues and with different densities. The sea urchins dispersed in random directions after being released. There was no significant difference in the movement speed and the displacement of sea urchins among the three density groups (1, 15 and 30 ind/m2). The interaction occurred when sea urchins randomly contacted with the conspecifics and slowed down the movement speed. The speed of sea urchins after physical contacts decreased by an average of 40% in the density of 15 ind/m2 and 17% in the density of 30 ind/m2. This interaction resulted in significantly higher randomness in the movement direction and lower movement linearity in 15 and 30 ind/m2 than in 1 ind/m2. After the introduction of food cues, the movement speed, displacement and dispersal distance of sea urchin groups decreased significantly in all the three densities. The dispersal distance and expansion speed of sea urchins were significantly lower in 30 ind/m2 than those in 15 ind/m2. The present study indicates that the interaction among sea urchins limits the movement of individual sea urchin and provides valuable information into how large groups of sea urchins are stable in places where food is plentiful.

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Re-evaluation of the structure and physiological function of guanidino kinases in fruitfly (Drosophila), sea urchin (Psammechinus miliaris) and man

Biochemical Journal ◽

10.1042/bj3090255 ◽

1995 ◽

Vol 309 (1) ◽

pp. 255-261 ◽

Cited By ~ 28

Author(s):

M Wyss ◽

D Maughan ◽

T Wallimann

Keyword(s):

Sea Urchin ◽

Sea Urchins ◽

Arginine Kinase ◽

Gel Permeation Chromatography ◽

Subcellular Fractionation ◽

Striated Muscles ◽

Biophysical Characterization ◽

Energy Demands ◽

Psammechinus Miliaris ◽

Oligomeric Form

Purification and biophysical characterization of mitochondrial creatine kinase (Mi-CK) from sperm of the sea urchin Psammechinus miliaris, as well as gel-permeation chromatography of human heart Mi-CK demonstrate that these two Mi-CK isoenzymes form highly symmetrical octameric molecules with an M(r) of approx. 350,000, a value similar to that found for all other Mi-CK isoenzymes investigated so far. The absolute evolutionary conservation of this oligomeric form from sea urchins to mammals points both to its essentiality for Mi-CK function and to an important role of octameric Mi-CK in the energy metabolism of tissues and cells with high and fluctuating energy demands. To investigate whether a similar physiological principle also operates in an even more distantly related animal phylum, the arginine kinase (ArgK) isoenzyme system of Drosophila flight muscle was investigated with two independent subcellular fractionation procedures and subsequent analysis of the fractions by SDS/PAGE, immunoblotting and native isoenzyme electrophoresis. In contrast with a previous report [Munneke and Collier (1988) Biochem. Genet. 26, 131-141], strong evidence against the occurrence of a Mi-ArgK isoenzyme in Drosophila was obtained. The findings of the present study are discussed in the context of CK and ArgK function in general and of structural and bioenergetic differences between vertebrate striated muscles and arthropod flight muscles.

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Spinochrome Identification and Quantification in Pacific Sea Urchin Shells, Coelomic Fluid and Eggs Using HPLC-DAD-MS

Marine Drugs ◽

10.3390/md19010021 ◽

2021 ◽

Vol 19 (1) ◽

pp. 21

Author(s):

Elena A. Vasileva ◽

Natalia P. Mishchenko ◽

Van T. T. Tran ◽

Hieu M. N. Vo ◽

Sergey A. Fedoreyev

Keyword(s):

Sea Urchin ◽

High Performance ◽

Sea Urchins ◽

Coelomic Fluid ◽

Chromatography Method ◽

Scaphechinus Mirabilis ◽

Mass Spectrometric Detector ◽

Egg Membrane ◽

First Time ◽

Identification And Quantification

The high-performance liquid chromatography method coupled with diode array and mass spectrometric detector (HPLC-DAD-MS) method for quinonoid pigment identification and quantification in sea urchin samples was developed and validated. The composition and quantitative ratio of the quinonoid pigments of the shells of 16 species of sea urchins, collected in the temperate (Sea of Japan) and tropical (South-China Sea) climatic zones of the Pacific Ocean over several years, were studied. The compositions of the quinonoid pigments of sea urchins Maretia planulata, Scaphechinus griseus, Laganum decagonale and Phyllacanthus imperialis were studied for the first time. A study of the composition of the quinonoid pigments of the coelomic fluid of ten species of sea urchins was conducted. The composition of quinonoid pigments of Echinarachnius parma jelly-like egg membrane, of Scaphechinus mirabilis developing embryos and pluteus, was reported for the first time. In the case of Scaphechinus mirabilis, we have shown that the compositions of pigment granules of the shell epidermis, coelomic fluid, egg membrane, developing embryos and pluteus are different, which should enable a fuller understanding of the functions of pigments at different stages of life.

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Bioactive Compounds in Salicornia patula Duval-Jouve: A Mediterranean Edible Euhalophyte

Foods ◽

10.3390/foods10020410 ◽

2021 ◽

Vol 10 (2) ◽

pp. 410

Author(s):

Irene Sánchez-Gavilán ◽

Esteban Ramírez ◽

Vicenta de la Fuente

Keyword(s):

Fatty Acids ◽

Bioactive Compounds ◽

Mediterranean Area ◽

Biological Properties ◽

Total Phenolic ◽

Tinto River ◽

New Findings ◽

High Concentrations ◽

Salicornia Patula ◽

First Time

Many halophytes have great nutritional and functional potential, providing chemical compounds with biological properties. Salicornia patula Duval-Jouve is a common euhalophyte from saline Mediterranean territories (Spain, Portugal, France, and Italy). In the present work we quantified for the first time the bioactive compounds in S. patula (total phenolic compounds and fatty acids), from Iberian Peninsula localities: littoral-coastal Tinto River basin areas (southwest Spain, the Huelva province), and mainland continental territories (northwest and central Spain, the Valladolid and Madrid provinces). Five phenolic acids including caffeic, coumaric, veratric, salicylic, and transcinnamic have been found with differences between mainland and coastal saltmarshes. S. patula contain four flavonoids: quercetin-3-O-rutinoside, kaempferol/luteolin, apigenin 7-glucoside, and pelargonidin-3-O-rutinoside. These last two glycosylated compounds are described for the first time in this genus of Chenopodiaceae. The fatty acid profile described in S. patula stems contains palmitic, oleic, and linoleic acids in high concentrations, while stearic and long-chain fatty acids were detected in low amounts. These new findings confirm that S. patula is a valuable source of bioactive compounds from Mediterranean area.

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Evidence for Association of Vibrio Echinoideorum with Tissue Necrosis on Body Shell of the Green Sea Urchin Strongylocentrotus Droebachiensis

10.21203/rs.3.rs-1085079/v1 ◽

2021 ◽

Author(s):

Jonathan Hira ◽

Klara Stensvåg

Keyword(s):

Sea Urchin ◽

Virulence Genes ◽

Vibrio Vulnificus ◽

Sea Urchins ◽

Opportunistic Pathogen ◽

Significant Degree ◽

Strongylocentrotus Droebachiensis ◽

Host Immune System ◽

Progressive Development ◽

Green Sea Urchin

Abstract “Sea urchin lesion syndrome” is known as sea urchins disease with the progressive development of necrotic epidermal tissue and loss of external organs, including appendages on the outer body surface. Recently, a novel strain, Vibrio echinoideorum has been isolated from the lesions of green sea urchin (Strongylocentrotus droebachiensis), an economically important mariculture species in Norway. V. echinoideorum has not been reported elsewhere in association of with green sea urchin lesion syndrome. Therefore, in this study, an immersion based bacterial challenge experiment was performed to expose sea urchins (wounded and non-wounded) to V. echinoideorum, thereby mimicking a nearly natural host-pathogen interaction under controlled conditions. This infection experiment demonstrated that only the injured sea urchins developed the lesion to a significant degree when exposed to V. echinoideorum. Pure cultures of the employed bacterial strain was recovered from the infected animals and its identity was confirmed by the MALDI-TOF MS spectra profiling. Additionally, the hemolytic phenotype of V. echinoideorum substantiated its virulence potential towards the host, and this was also supported by the cytolytic effect on red spherule cells of sea urchins. Furthermore, the genome sequence of V. echinoideorum was assumed to encode potential virulence genes and were subjected for in silico comparison with the established virulence factors of Vibrio vulnificus and Vibrio tasmaniensis. This comparative virulence profile provided novel insights about virulence genes and their putative functions related to chemotaxis, adherence, invasion, evasion of the host immune system, and damage of host tissue and cells. Thus, it supports the pathogenicity of V. echinoideorum. In conclusion, the interaction of V. echinoideorum with injured sea urchins appears to be essential for the development of lesion syndrome and therefore, revealing its potentiality as an opportunistic pathogen.

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The Mechanism of Cell-division

Journal of Cell Science ◽

10.1242/jcs.s3-94.28.369 ◽

1953 ◽

Vol s3-94 (28) ◽

pp. 369-379

Author(s):

M. M. SWANN

Keyword(s):

Carbon Monoxide ◽

Cell Division ◽

Sea Urchin ◽

White Light ◽

Time Lapse ◽

Psammechinus Miliaris ◽

Energy Store ◽

Time Lapse Photography

1. Developing eggs of the sea-urchin Psammechinus miliaris were subjected to carbon monoxide inhibition, which was controlled by changing from green to white light. The behaviour of the eggs was recorded by time-lapse photography. 2. If inhibition is applied before the eggs enter mitosis, their first cleavage is delayed by a time which is roughly equal to the period of the inhibition. 3. If the inhibition is applied when the cells have already entered mitosis, they complete mitosis and cleave with little or no delay, but their second cleavage is delayed by a time which is roughly equal to the period of the inhibition. 4. It is suggested that the necessary energy for the second mitosis and cleavage is being stored up during the first mitosis and cleavage, and that this energy store operates like a reservoir which is continually being filled but siphons out when it is full. Once the energy has siphoned out, it carries mitosis and cleavage through, even though the reservoir is not filling up because of carbon monoxide inhibition.

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