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

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.

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Trans-Species Polymorphism in Mitochondrial Genome of Camarodont Sea Urchins

Genes ◽

10.3390/genes10080592 ◽

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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Changes in levels of major yolk protein in the coelomic fluid and gonad during the reproductive cycle in wild sea urchins,Mesocentrotus nudus

10.1101/241059 ◽

2017 ◽

Author(s):

Kazuhiro Ura ◽

Narumi Takei ◽

Ichiro Higuchi ◽

Tomoharu Yuhi ◽

Osamu Nishimiya ◽

...

Keyword(s):

Reproductive Cycle ◽

Sexual Maturity ◽

Sea Urchins ◽

Gonadosomatic Index ◽

Yolk Protein ◽

Coelomic Fluid ◽

Mature Stage ◽

Positive Correlation ◽

Mesocentrotus Nudus ◽

Quantitative Changes

AbstractBoth female and male sea urchins accumulate the major yolk protein (MYP) in the nutritive phagocytes of immature gonads before gametogenesis, and MYP is the most abundant protein in the coelomic fluid of both sexes. In females, MYP in the coelomic fluid is taken up by the nutritive phagocytes and transported to the growing oocytes. This study examined quantitative changes of MYP in the coelomic fluid of both sexes during the reproductive cycle of wild sea urchins,Mesocentrotus nudus. Levels of MYP in the coelomic fluid of females increased and reached a peak at the histological pre-mature stage of gonad activity (i.e. Stage 3), and positive correlation between the MYP level and the gonadosomatic index (GSI) was observed. In male sea urchins the level of MYP in the coelomic fluid increased at the pre-mature stage, though positive correlation between the MYP level and GSI was not observed. These results indicate that MYP in the coelomic fluid is suitable as a biomarker of the onset and progression of sexual maturity in female sea urchins.

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Feeding the sporophyll of Undaria pinnatifida kelp shortens the culture duration for the production of high-quality gonads of Mesocentrotus nudus sea urchins from a barren

Aquaculture ◽

10.1016/j.aquaculture.2020.735503 ◽

2020 ◽

Vol 528 ◽

pp. 735503 ◽

Cited By ~ 2

Author(s):

Satomi Takagi ◽

Yuko Murata ◽

Yukio Agatsuma

Keyword(s):

Undaria Pinnatifida ◽

Sea Urchins ◽

High Quality ◽

Culture Duration ◽

Mesocentrotus Nudus

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Towards a scientific-based farming of sea urchins: First steps in the cultivation of Diadema setosum, Diadema savignyi and Mesocentrotus nudus

APN Science Bulletin ◽

10.30852/sb.2020.1284 ◽

2020 ◽

Author(s):

Salim Dautov ◽

Tatiana Dautova ◽

Svetlana Kashenko

Keyword(s):

South China Sea ◽

Larval Development ◽

South China ◽

Sea Urchins ◽

Japan Sea ◽

Tropical Zone ◽

Cultivated Species ◽

Mesocentrotus Nudus ◽

Pluteus Stage ◽

Diadema Setosum

FISHING OR BREEDING. This question arose relatively recently, but in the last decade, mankind will have to lean more towards the second. Sea reserves of useful species are exhausted. One possible solution to this problem is marine farming. We proposed to investigate the larval development of three sea urchin species: Diadema setosum (Leske, 1778), D. savignyi (Audouin, 1829) (South China Sea), and Mesocentrotus nudus (A. Agassiz, 1864) (Japan Sea). The larvae of Diadema setosum and D. savignyi were very similar, and some differences could only be observed at the late pluteus stage. These sea urchins were developed through the modified pluteus, which only had two pairs of larval arms. The arms were very long - in D. setosum above 2 mm, and in D. savignyi about 5.5 mm. Larval development took about 45 days in D. setosum and 47–50 days in D. savignyi. In contrast, Mesocentrotus nudus (A. Agassiz, 1864) was developed through the pluteus larvae, which had some differences from the pluteus of the genus Strongylocentrotus. Their dimensions did not reach one millimetre. The larval development of Mesocentrotus nudus lasted about 30 days. Analysis of material and time costs has led to the conclusion that Mesocentrotus nudus is the most convenient for obtaining seed material. However, this species cannot be used for the tropical zone. The results of D. savignyi and D. setosum can be used to increase the number of cultivated species.

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Effects of the brown algae Sargassum horneri and Saccharina japonica on survival, growth and resistance of small sea urchins Strongylocentrotus intermedius

Scientific Reports ◽

10.1038/s41598-020-69435-8 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Fangyuan Hu ◽

Mingfang Yang ◽

Peng Ding ◽

Xu Zhang ◽

Zhouling Chen ◽

...

Keyword(s):

Brown Algae ◽

Sea Urchins ◽

Saccharina Japonica ◽

Sargassum Horneri ◽

Strongylocentrotus Intermedius

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

Frontiers in Marine Science ◽

10.3389/fmars.2021.802754 ◽

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.

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