Effect of dopamine on early larvae of sea urchins, Mesocentrotus nudus and Strongylocentrotus intermedius

2020 ◽  
Vol 334 (6) ◽  
pp. 373-380
Author(s):  
Alexander V. Kalachev
Keyword(s):  
Sea Urchins ◽  
Strongylocentrotus Intermedius ◽  
Mesocentrotus Nudus ◽  
Early Larvae

scholarly journals The Structure and Function of Gut Microbiomes of Two Species of Sea Urchins, Mesocentrotus nudus and Strongylocentrotus intermedius, in Japan

2021 ◽  
Vol 8 ◽  
Author(s):  
Alfabetian Harjuno Condro Haditomo ◽  
Masanori Yonezawa ◽  
Juanwen Yu ◽  
Sayaka Mino ◽  
Yuichi Sakai ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Gut Microbiome ◽  
Environmental Changes ◽  
Growth Promotion ◽  
Sea Urchins ◽  
The Body ◽  
Sequence Variant ◽  
Strongylocentrotus Intermedius ◽  
Running Water ◽  
Mesocentrotus Nudus

Sea urchin is an indicator of coastal environmental changes in the global warming era, and is also a model organism in developmental biology and evolution. Due to the depletion of wild resources, new aquaculture techniques for improving stocks have been well studied. The gut microbiome shapes various aspects of a host’s physiology. However, these microbiome structures and functions on sea urchins, particularly Mesocentrotus nudus and Strongylocentrotus intermedius which are important marine bioresources commonly found in Japan, have not been fully investigated yet. Using metagenomic approaches including meta16S and shotgun metagenome sequencings, the structures, functions, and dynamics of the gut microbiome of M. nudus and S. intermedius, related to both habitat environment and host growth, were studied. Firstly, a broad meta16S analysis revealed that at the family level, Psychromonadaceae and Flavobacteriaceae reads (38–71%) dominated in these sea urchins, which is a unique feature observed in species in Japan. Flavobacteriaceae reads were more abundant in individuals after rearing in an aquarium with circulating compared to one with running water. Campylobacteraceae and Vibrionaceae abundances increased in both kinds of laboratory-reared sea urchins in both types of experiments. 2-weeks feeding experiments of M. nudus and S. intermedius transplanted from the farm to laboratory revealed that these gut microbial structures were affected by diet rather than rearing environments and host species. Secondly, further meta16S analysis of microbial reads related to M. nudus growth revealed that at least four Amplicon Sequence Variant (ASV) affiliated to Saccharicrinis fermentans, which is known to be a nitrogen (N2) fixing bacterium, showed a significant positive correlation to the body weight and test diameter. Interestingly, gut microbiome comparisons using shotgun metagenome sequencing of individuals showing higher and lower growth rates revealed a significant abundance of “Nitrate and nitrite ammonification” genes in the higher-grown individuals under the circulating water rearing. These findings provide new insights on the structure-function relationship of sea urchin gut microbiomes beyond previously reported nitrogen fixation function in sea urchin in 1950s; we discovered a nitrate reduction function into ammonium for the growth promotion of sea urchin.

scholarly journals Quantitative study of the behavior of two broadcast spawners, the sea urchins Strongylocentrotus intermedius and Mesocentrotus nudus, during mass spawning events in situ

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11058
Author(s):  
Peter M. Zhadan ◽  
Marina A. Vaschenko ◽  
Peter A. Permyakov
Keyword(s):  
Reproductive Success ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Total Duration ◽  
Strongylocentrotus Intermedius ◽  
Mass Spawning ◽  
Behavioral Adaptations ◽  
Males And Females ◽  
Mesocentrotus Nudus

Background The spatial distribution of spawners and temporal parameters of spawning in motile invertebrates with external fertilization might influence reproductive success. However, to date, data on the prespawning and spawning behaviors of broadcast spawners in the field have been scarce and mostly qualitative. The present study was intended to clarify the behavioral adaptations of two sea urchin species, Strongylocentrotus intermedius and Mesocentrotus nudus, using quantitative analysis of their behavior during mass spawning events under natural conditions. Methods We analyzed in situ video recordings of sea urchin behavior obtained during six spawning seasons (2014–2019). The total number of specimens of each sea urchin species and the numbers of spawning males and females were counted. Quantitative parameters of sea urchin spawning (numbers of gamete batches, release duration of one gamete batch, time intervals between gamete batches and total duration of spawning) and movement (step length of spawners and nonspawners before and during spawning and changes in distances between males/nonspawners and females) were determined. Results For each species, 12 mass spawning events were recorded in which 10 or more individuals participated. The temporal dynamics of the numbers of males and females participating in mass spawning were well synchronized in both species; however, males began to spawn earlier and ended their spawning later than females. In both species, the most significant intersex difference was the longer spawning duration in males due to the longer pause between gamete batches. The total duration of gamete release did not differ significantly between sexes. The average duration of sperm release during mass spawning events was longer than solitary male spawning. Males and females showed significant increases in the locomotion rate 35 min before the start of spawning and continued to actively move during spawning. An increase in movement rate before spawning in males and females was induced by environmental factor(s). Nonspawners of both species showed increased locomotion activity but in the presence of spawning neighbors and less prominently than spawners. On a vertical surface, both echinoids moved strictly upward. On flat surfaces, males, females and nonspawners of both echinoids became closer during spawning. Discussion We showed that two sea urchin species with planktotrophic larvae display similar behavioral adaptations aimed at enhancing reproductive success. The high sensitivity of sea urchins, primarily males, to some environmental factors, most likely phytoplankton, may be considered a large-scale adaptation promoting the development of mass spawning events. The longer spawning duration in males and increased movement activity before and during spawning in both sexes may be considered small-scale adaptations promoting approach of males and females and enhancing the chances of egg fertilization.

scholarly journals Light intensity regulates phototaxis, foraging and righting behaviors of the sea urchin Strongylocentrotus intermedius

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8001 ◽  
Author(s):  
Jiangnan Sun ◽  
Xiaomei Chi ◽  
Mingfang Yang ◽  
Jingyun Ding ◽  
Dongtao Shi ◽  
...  
Keyword(s):  
Light Intensity ◽  
Foraging Behavior ◽  
Sea Urchins ◽  
High Light Intensity ◽  
High Light ◽  
Strongylocentrotus Intermedius ◽  
Low Light ◽  
Low Light Intensity ◽  
Light Intensities ◽  
Significant Difference

Small sea urchins Strongylocentrotus intermedius (1–2 cm of test diameter) are exposed to different environments of light intensities after being reseeded to the sea bottom. With little information available about the behavioral responses of S. intermedius to different light intensities in the environment, we carried out an investigation on how S. intermedius is affected by three light intensity environments in terms of phototaxis, foraging and righting behaviors. They were no light (zero lx), low light intensity (24–209 lx) and high light intensity (252–2,280 lx). Light intensity had obvious different effects on phototaxis. In low light intensity, sea urchins moved more and spent significantly more time at the higher intensity (69–209 lx) (P = 0.046). S. intermedius in high light intensity, in contrast, spent significantly more time at lower intensity (252–690 lx) (P = 0.005). Unexpectedly, no significant difference of movement (average velocity and total distance covered) was found among the three light intensities (P > 0.05). Foraging behavior of S. intermedius was significantly different among the light intensities. In the no light environment, only three of ten S. intermedius found food within 7 min. In low light intensity, nine of 10 sea urchins showed successful foraging behavior to the food placed at 209 lx, which was significantly higher than the ratio of the number (two of 10) when food was placed at 24 lx (P = 0.005). In the high light intensity, in contrast, significantly less sea urchins (three of 10) found food placed at the higher light intensity (2,280 lx) compared with the lower light intensity (252 lx) (10/10, P = 0.003). Furthermore, S. intermedius showed significantly longer righting response time in the high light intensity compared with both no light (P = 0.001) and low light intensity (P = 0.031). No significant difference was found in righting behavior between no light and low light intensity (P = 0.892). The present study indicates that light intensity significantly affects phototaxis, foraging and righting behaviors of S. intermedius and that ~200 lx might be the appropriate light intensity for reseeding small S. intermedius.

Dietary Effect of Kelp (Saccharina japonica) on Gonad Quantity and Quality in Sea Urchins (Mesocentrotus nudus) Collected from a Barren Before the Fishing Season

2018 ◽  
Vol 37 (3) ◽  
pp. 659-669 ◽  
Author(s):  
Satomi Takagi ◽  
Yuko Murata ◽  
Eri Inomata ◽  
Hikaru Endo ◽  
Masakazu N. Aoki ◽  
...  
Keyword(s):  
Sea Urchins ◽  
Saccharina Japonica ◽  
Fishing Season ◽  
Mesocentrotus Nudus

Impacts of water temperature on the physiology and behaviours of the sea urchins Heliocidaris crassispina and Mesocentrotus nudus that reflect their range extension and disappearance in the Oga Peninsula, northern Honshu, Japan

2020 ◽  
Author(s):  
Wenping Feng ◽  
Nobuyasu Nakabayashi ◽  
Eri Inomata ◽  
Masakazu N. Aoki ◽  
Yukio Agatsuma
Keyword(s):  
Low Temperature ◽  
Native Species ◽  
Feeding Rate ◽  
Sea Urchins ◽  
Temperature Limit ◽  
Feeding Rates ◽  
Righting Response ◽  
Mesocentrotus Nudus ◽  
Temperature Rate ◽  
High Or Low Temperature

Ocean warming has facilitated the extension of Heliocidaris crassispina to Oga Peninsula, Japan, where the native species Mesocentrotus nudus has disappeared. To verify the temperature impacts on the physiology and behaviour of the two species, we reared small sea urchins at the increasing/decreasing temperature rate of 2.5°C week-1. The righting response, lantern reflex, gonad and gut carbon (C) and nitrogen (N) contents, and feeding rate were investigated. The high and low temperature limits of H. crassispina were 33.3°C and 3.9°C, respectively, which were higher than those of M. nudus. The optimal temperature ranges for behaviour and feeding in H. crassispina were 10.3–31.0°C and 10.3–33.4°C, respectively, which were higher than those in M. nudus. Feeding rates decreased significantly in both species when the temperature approached the high or low temperature limit, but the gut C and N contents of were not greatly affected. At 26–31°C, the feeding rate significantly decreased in M. nudus but not in H. crassispina, which may explain the replacement of M. nudus by H. crassispina in the Oga Peninsula.

scholarly journals Trans-Species Polymorphism in Mitochondrial Genome of Camarodont Sea Urchins

Genes ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 592
Author(s):  
Evgeniy S. Balakirev
Keyword(s):  
Sea Urchins ◽  
Stop Codon ◽  
Global Ocean ◽  
Abrupt Climate Change ◽  
Local Alignment ◽  
Codon Reassignment ◽  
Length Difference ◽  
Search Tool ◽  
Alternative Hypotheses ◽  
Mesocentrotus Nudus

Mitochondrial (mt) genomes of the sea urchins Strongylocentrotus intermedius and Mesocentrotus nudus demonstrate the identical patterns of intraspecific length variability of the ND6 gene, consisting of 489 bp (S variant) and 498 bp (L variant), respectively. For both species, the ND6 length difference is due to the 488A>G substitution, which changes the stop codon TAG in S variant for a tryptophan codon TGG in L variant and elongates the corresponding ND6 protein by three additional amino acids, Trp-Leu-Trp. The phylogenetic analysis based on mt genomes of sea urchins and related echinoderm groups from GenBank has shown the S and L ND6 variants as shared among the camarodont sea urchins; the rest of the echinoderms demonstrate the S variant only. The data suggest that the ND6 488A>G substitution can be the first example of the trans-species polymorphism in sea urchins, persisting at least since the time of the Odontophora diversification at the Eocene/Oligocene boundary (approximately 34 million years ago), which was characterized by an abrupt climate change and significant global ocean cooling. Alternative hypotheses, including the convergent RNA editing and/or codon reassignment, are not supported by direct comparisons of the ND6 gene sequences with the corresponding transcripts using the basic local alignment search tool (BLAST) of full sea urchin transcriptomes.

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