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Zunchun Zhou - One of the best experts on this subject based on the ideXlab platform.
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De novo transcriptomic analysis of gonad of Strongylocentrotus nudus and gene discovery for biosynthesis of polyunsaturated fatty acids.
Genes & genomics, 2019Co-Authors: Zhenlin Wei, Xiaolin Liu, Zunchun ZhouAbstract:Strongylocentrotus nudus is an important cultured sea urchin species in north China, because its gonad is rich in unsaturated fatty acids, particularly long polyunsaturated fatty acids (LC-PUFAs). These PUFAs play pleiotropic and crucial roles in a wide range of biological process. However, the genes contributing to biosynthesis PUFAs have not been elucidated yet, and the molecular mechanism relative to the difference in PUFA composition between male and female gonad as been revealed but the corresponding has not been understood. In this paper, solexa sequencing based transcriptomic approach was used to identify and characterize the key genes relative to PUFA synthesis and further conducted different expressed genes between male and female gonad. A total of 130,124 transcripts and 189330 unigenes were de novo assembled from 64.32 Gb data. Next, these unigenes were subjected to functional annotation by mapping to six public databases, and this process revealed a lot of genes involving in lipid metabolism. In addition, three types of fatty acids front-end desaturase and three species of very long fatty acids elongase were identified and the pathway for PUFA biosynthesis was hypothesized. Last, comparative analysis revealed the higher expression level of Δ5 desaturase, Δ6 desaturase, ELOVL-4, -6 and -7 in male gonad compared with female. This results could plausible explain the differ in composition of PUFAs between male and female gonad of sea urchin.
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De novo transcriptome sequencing and comparative analysis to discover genes involved in ovarian maturity in Strongylocentrotus nudus.
Comparative biochemistry and physiology. Part D Genomics & proteomics, 2017Co-Authors: Zhiying Jia, Zunchun Zhou, Zhenlin Wei, Qiai Wang, Xiaolin LiuAbstract:Abstract Strongylocentrotus nudus is an edible sea urchin, mainly harvested in China. Correlation studies indicated that S. nudus with larger diameter have a prolonged marketing time and better palatability owing to their precocious gonads and extended maturation process. However, the molecular mechanism underlying this phenomenon is still unknown. Here, transcriptome sequencing was applied to study the ovaries of adult S. nudus with different shell diameters to explore the possible mechanism. In this study, four independent cDNA libraries were constructed, including two from the big size urchins and two from the small ones using a HiSeq™2500 platform. A total of 88,581 unigenes were acquired with a mean length of 1354 bp, of which 66,331 (74.88%) unigenes could be annotated using six major publicly available databases. Comparative analysis revealed that 353 unigenes were differentially expressed (with log2(ratio) ≥ 1, FDR ≤ 0.001) between the two groups. Of these, 20 differentially expressed genes (DEGs) were selected to confirm the accuracy of RNA-seq data by quantitative real-time RT-PCR. Furthermore, gene ontology and KEGG pathway enrichment analyses were performed to find the putative genes and pathways related to ovarian maturity. Eight unigenes were identified as significant DEGs involved in reproduction related pathways; these included Mos , Cdc20 , Rec8 , YP30 , cytochrome P450 2U1 , ovoperoxidase , proteoliaisin , and rendezvin . Our research fills the gap in the studies on the S. nudus ovaries using transcriptome analysis.
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De novo transcriptome sequencing and comparative analysis to discover genes involved in ovarian maturity in Strongylocentrotus nudus Part D Genomics and proteomics
Comparative Biochemistry and Physiology, 2017Co-Authors: Zhiying Jia, Zunchun Zhou, Zhenlin Wei, Qiai Wang, Xiaolin LiuAbstract:Strongylocentrotus nudus is an edible sea urchin, mainly harvested in China. Correlation studies indicated that S. nudus with larger diameter have a prolonged marketing time and better palatability owing to their precocious gonads and extended maturation process. However, the molecular mechanism underlying this phenomenon is still unknown. Here, transcriptome sequencing was applied to study the ovaries of adult S. nudus with different shell diameters to explore the possible mechanism. In this study, four independent cDNA libraries were constructed, including two from the big size urchins and two from the small ones using a HiSeq™2500 platform. A total of 88,581 unigenes were acquired with a mean length of 1354bp, of which 66,331 (74.88%) unigenes could be annotated using six major publicly available databases. Comparative analysis revealed that 353 unigenes were differentially expressed (with log2(ratio)≥1, FDR≤0.001) between the two groups. Of these, 20 differentially expressed genes (DEGs) were selected to confirm the accuracy of RNA-seq data by quantitative real-time RT-PCR. Furthermore, gene ontology and KEGG pathway enrichment analyses were performed to find the putative genes and pathways related to ovarian maturity. Eight unigenes were identified as significant DEGs involved in reproduction related pathways; these included Mos, Cdc20, Rec8, YP30, cytochrome P450 2U1, ovoperoxidase, proteoliaisin, and rendezvin. Our research fills the gap in the studies on the S. nudus ovaries using transcriptome analysis.
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High-Density Genetic Mapping with Interspecific Hybrids of Two Sea Urchins, Strongylocentrotus nudus and S. intermedius, by RAD Sequencing.
PloS one, 2015Co-Authors: Zunchun Zhou, Shikai Liu, Ying Dong, Shan Gao, Zhong Chen, Jingwei Jiang, Aifu Yang, Hongjuan Sun, Xiaoyan Guan, Bei JiangAbstract:Sea urchins have long been used as research model organisms for developmental biology and evolutionary studies. Some of them are also important aquaculture species in East Asia. In this work, we report the construction of RAD-tag based high-density genetic maps by genotyping F1 interspecific hybrids derived from a crossing between a female sea urchin Strongylocentrotus nudus and a male Strongylocentrotus intermedius. With polymorphisms present in these two wild individuals, we constructed a female meiotic map containing 3,080 markers for S. nudus, and a male meiotic map for S. intermedius which contains 1,577 markers. Using the linkage maps, we were able to anchor a total of 1,591 scaffolds (495.9 Mb) accounting for 60.8% of the genome assembly of Strongylocentrotus purpuratus. A genome-wide scan resulted in the identification of one putative QTL for body size which spanned from 25.3 cM to 30.3 cM. This study showed the efficiency of RAD-Seq based high-density genetic map construction using F1 progenies for species with no prior genomic information. The genetic maps are essential for QTL mapping and are useful as framework to order and orientate contiguous scaffolds from sea urchin genome assembly. The integration of the genetic map with genome assembly would provide an unprecedented opportunity to conduct QTL analysis, comparative genomics, and population genetics studies.
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Identification and characterization of proteins with phenoloxidase-like activities in the sea urchin Strongylocentrotus nudus.
Fish & shellfish immunology, 2015Co-Authors: Yuhui Cheng, Jingwei Jiang, Ying Dong, Zunchun ZhouAbstract:Three proteins with PO-like activities in the coelomocytes of sea urchin Strongylocentrotus nudus were identified using electrophoretic method and named as SnPO1, SnPO2 and SnPO3 according to their molecular mass from high to low. The SnPOs were characterized for substrate specificity and the effects of temperature, pH, divalent metal ions and inhibitors on PO activities. They showed oxidative activities to L-3,4-dihydroxyphenylalanine. (l-DOPA), dopamine and hydroquinone, but failed to oxidize tyrosine, which illustrated the three proteins had laccase-like PO activities. The optimum temperature for the activities of SnPO1, SnPO2 and SnPO3 was 75 °C, 70 °C, 40 °C, and the optimum pH was 7.0, 9.0, 8.0, respectively. The SnPOs were notably activated after being incubated in boiled water for 60 min, suggesting that the three proteins are thermophilic. The activity of SnPO1 was greatly enhanced by Cu(2+), Mn(2+) and Fe(2+) and inhibited by Pb(2+), Cd(2+), EDTA, DETC, sodium sulfite and ascorbic acid, but SnPO2 and SnPO3 were not obviously affected by Pb(2+) and Cd(2+), suggesting the three proteins are copper-containing, and the catalytic properties of SnPO1 might be different from those of SnPO2 and SnPO3. Taken together, SnPO1, SnPO2 and SnPO3 might play different roles in the immune and physiological processes of S. nudus.
Xiaolin Liu - One of the best experts on this subject based on the ideXlab platform.
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De novo transcriptomic analysis of gonad of Strongylocentrotus nudus and gene discovery for biosynthesis of polyunsaturated fatty acids.
Genes & genomics, 2019Co-Authors: Zhenlin Wei, Xiaolin Liu, Zunchun ZhouAbstract:Strongylocentrotus nudus is an important cultured sea urchin species in north China, because its gonad is rich in unsaturated fatty acids, particularly long polyunsaturated fatty acids (LC-PUFAs). These PUFAs play pleiotropic and crucial roles in a wide range of biological process. However, the genes contributing to biosynthesis PUFAs have not been elucidated yet, and the molecular mechanism relative to the difference in PUFA composition between male and female gonad as been revealed but the corresponding has not been understood. In this paper, solexa sequencing based transcriptomic approach was used to identify and characterize the key genes relative to PUFA synthesis and further conducted different expressed genes between male and female gonad. A total of 130,124 transcripts and 189330 unigenes were de novo assembled from 64.32 Gb data. Next, these unigenes were subjected to functional annotation by mapping to six public databases, and this process revealed a lot of genes involving in lipid metabolism. In addition, three types of fatty acids front-end desaturase and three species of very long fatty acids elongase were identified and the pathway for PUFA biosynthesis was hypothesized. Last, comparative analysis revealed the higher expression level of Δ5 desaturase, Δ6 desaturase, ELOVL-4, -6 and -7 in male gonad compared with female. This results could plausible explain the differ in composition of PUFAs between male and female gonad of sea urchin.
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De novo transcriptome sequencing and comparative analysis to discover genes involved in ovarian maturity in Strongylocentrotus nudus.
Comparative biochemistry and physiology. Part D Genomics & proteomics, 2017Co-Authors: Zhiying Jia, Zunchun Zhou, Zhenlin Wei, Qiai Wang, Xiaolin LiuAbstract:Abstract Strongylocentrotus nudus is an edible sea urchin, mainly harvested in China. Correlation studies indicated that S. nudus with larger diameter have a prolonged marketing time and better palatability owing to their precocious gonads and extended maturation process. However, the molecular mechanism underlying this phenomenon is still unknown. Here, transcriptome sequencing was applied to study the ovaries of adult S. nudus with different shell diameters to explore the possible mechanism. In this study, four independent cDNA libraries were constructed, including two from the big size urchins and two from the small ones using a HiSeq™2500 platform. A total of 88,581 unigenes were acquired with a mean length of 1354 bp, of which 66,331 (74.88%) unigenes could be annotated using six major publicly available databases. Comparative analysis revealed that 353 unigenes were differentially expressed (with log2(ratio) ≥ 1, FDR ≤ 0.001) between the two groups. Of these, 20 differentially expressed genes (DEGs) were selected to confirm the accuracy of RNA-seq data by quantitative real-time RT-PCR. Furthermore, gene ontology and KEGG pathway enrichment analyses were performed to find the putative genes and pathways related to ovarian maturity. Eight unigenes were identified as significant DEGs involved in reproduction related pathways; these included Mos , Cdc20 , Rec8 , YP30 , cytochrome P450 2U1 , ovoperoxidase , proteoliaisin , and rendezvin . Our research fills the gap in the studies on the S. nudus ovaries using transcriptome analysis.
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De novo transcriptome sequencing and comparative analysis to discover genes involved in ovarian maturity in Strongylocentrotus nudus Part D Genomics and proteomics
Comparative Biochemistry and Physiology, 2017Co-Authors: Zhiying Jia, Zunchun Zhou, Zhenlin Wei, Qiai Wang, Xiaolin LiuAbstract:Strongylocentrotus nudus is an edible sea urchin, mainly harvested in China. Correlation studies indicated that S. nudus with larger diameter have a prolonged marketing time and better palatability owing to their precocious gonads and extended maturation process. However, the molecular mechanism underlying this phenomenon is still unknown. Here, transcriptome sequencing was applied to study the ovaries of adult S. nudus with different shell diameters to explore the possible mechanism. In this study, four independent cDNA libraries were constructed, including two from the big size urchins and two from the small ones using a HiSeq™2500 platform. A total of 88,581 unigenes were acquired with a mean length of 1354bp, of which 66,331 (74.88%) unigenes could be annotated using six major publicly available databases. Comparative analysis revealed that 353 unigenes were differentially expressed (with log2(ratio)≥1, FDR≤0.001) between the two groups. Of these, 20 differentially expressed genes (DEGs) were selected to confirm the accuracy of RNA-seq data by quantitative real-time RT-PCR. Furthermore, gene ontology and KEGG pathway enrichment analyses were performed to find the putative genes and pathways related to ovarian maturity. Eight unigenes were identified as significant DEGs involved in reproduction related pathways; these included Mos, Cdc20, Rec8, YP30, cytochrome P450 2U1, ovoperoxidase, proteoliaisin, and rendezvin. Our research fills the gap in the studies on the S. nudus ovaries using transcriptome analysis.
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Identification and profiling of sex-biased microRNAs from sea urchin Strongylocentrotus nudus gonad by Solexa deep sequencing.
Comparative biochemistry and physiology. Part D Genomics & proteomics, 2014Co-Authors: Zhenlin Wei, Zunchun Zhou, Xiaolin LiuAbstract:MicroRNAs (miRNAs) are a class of endogenous small non-coding RNAs that regulate gene expression by post-transcriptional repression of messenger RNA. The echinoderm, Strongylocentrotus nudus, is an excellent model organism for studying development and commercially important as a food source. However, to date no miRNAs have been reported to modulate sex gonad differentiation in S. nudus. In this study, we constructed two small RNA libraries from male and female S. nudus gonad respectively for Solexa sequencing. A total of 184 miRNAs including 60 known and 124 novel miRNAs were identified from the two libraries. Furthermore, the nucleotide bias and end variation of the known miRNAs were also analyzed. In addition, 67 differently expressed of the 86 co-expressed and 98 gender-specific (47 male-specific and 51 female-specific) miRNAs that may be involved in sexual differentiation were found by comparing the miRNA expression profiles in the two libraries. This study reveals the first miRNA profile related to the gonad differentiation of the S. nudus. This study gives a first insight into sex differences in miRNA expression of sea urchin which could facilitate studies of the reproductive organ-specific roles of miRNAs.
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Identification and characterization of piRNA-like small RNAs in the gonad of sea urchin (Strongylocentrotus nudus).
Marine biotechnology (New York N.Y.), 2011Co-Authors: Zhenlin Wei, Xiaolin Liu, Huilin ZhangAbstract:Piwi-interacting RNAs (piRNAs) and their partner PIWI proteins play an essential role in fertility, germline stem cell development, as well as the basic control and evolution of animal genomes. However, research was rare with regard to piRNA population in sea urchin, a model animal intensively used for development and genetics studies. Utilizing Solexa sequencing, we present an identification of 13,051 piRNA-like RNAs expressed in male gonad of Strongylocentrotus nudus. Out of 202 tested RNAs, 94 sequences were confirmed to express in female gonad using microarray assay, suggesting that both male and female gonads are piRNA-like RNA-enriched organs. These RNAs with “U” at the 5′ end or “A” at position of 10, in size from 26 to 30 nucleotides, were predominantly 28 nt in length and tend to be clustered in small regions in genome, achieving the longest piRNA-like RNA-enriched region about 5.5 kb in scaffold78427. Alignment results showed 11 RNAs were homologous to the known piRNAs. Furthermore, BLASTn searching against sea urchin repeat element database showed these piRNA-like RNAs matched to 101 types of DNA transposons and retrotransposons, of which SPRP1, Harbinger-N2, piggyBac-N10, SINE2-1, and piggyBac-N11 were the most frequent hit elements, suggesting a transposon silencing function of these piRNA-like RNAs.
Yukio Agatsuma - One of the best experts on this subject based on the ideXlab platform.
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chapter 29 Strongylocentrotus nudus
Developments in Aquaculture and Fisheries Science, 2013Co-Authors: Yukio AgatsumaAbstract:Strongylocentrotus nudus is a dominant sea urchin species in the north west Pacific. They recruit on coralline flats and migrate to kelp forests when one year old or older. Somatic and gonadal growth is supported by brown macroalgae. Strongylocentrotus nudus forms high population densities that can result in over-grazing. Its high growth rate, great longevity, high reproductive efforts, reproduction after a period of maximum feeding, and growth responses to food availability are characteristics of a competitive species.
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Chapter 29 – Strongylocentrotus nudus
Developments in Aquaculture and Fisheries Science, 2013Co-Authors: Yukio AgatsumaAbstract:Strongylocentrotus nudus is a dominant sea urchin species in the north west Pacific. They recruit on coralline flats and migrate to kelp forests when one year old or older. Somatic and gonadal growth is supported by brown macroalgae. Strongylocentrotus nudus forms high population densities that can result in over-grazing. Its high growth rate, great longevity, high reproductive efforts, reproduction after a period of maximum feeding, and growth responses to food availability are characteristics of a competitive species.
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Inhibitory effect of 2,4-dibromophenol and 2,4,6-tribromophenol on larval survival and metamorphosis of the sea urchin Strongylocentrotus nudus
Fisheries Science, 2008Co-Authors: Yukio Agatsuma, Hikaru Endo, Kazuya TaniguchiAbstract:As a possible factor leading to the low recruitment level of sea urchins in kelp forests, the inhibitory effect of 2,4-dibromophenol (DBP) and 2,4,6-tribromophenol (TBP) released from the large perennial brown algae Ecklonia kurome and Eisenia bicyclis on survival and metamorphosis of eight-armed larvae of the sea urchin Strongylocentrotus nudus was examined. The percentage of larvae that underwent metamorphosis in filtered sea water after 1 h exposure to one-half dilution of saturated dibromomethane solution (≈60 ppm) as a chemical inducer reached approximately 100% after 1 h, while that in filtered sea water containing 1 ppm TBP was reduced to 73%. This was further reduced to less than 40% in the presence of 10 and 20 ppm TBP after 2 h. In filtered sea water containing 1 and 10 ppm DBP, the proportion of metamorphosed larvae was reduced markedly to 43 and 5% after 2 h, respectively. All larvae exposed to 50 ppm TBP and to 20 and 50 ppm DBP died after 1 h. These findings suggest that DBP is more toxic than TBP for sea urchin larvae, strongly inhibiting their metamorphosis.
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Food of the sea urchins Strongylocentrotus nudus and Hemicentrotus pulcherrimus associated with vertical distributions in fucoid beds and crustose coralline flats in northern Honshu, Japan
Marine Ecology Progress Series, 2007Co-Authors: Hikaru Endo, Yukio Agatsuma, Nobuyasu Nakabayashi, Kazuya TaniguchiAbstract:The vertical distribution and food of Strongylocentrotus nudus and Hemicentrotus pulcherrimus in fucoid beds at depths of 0.3 to 2.4 m and coralline flats at depths of 2.4 to 4.7 m were studied monthly from May 2001 to May 2002 off the Oga Peninsula, Akita prefecture, northern Japan. No seasonal migration of S. nudus from coralline flats to the fucoid beds occurred, as sufficient food was available in the form of sessile animals. Crustose corallines were generally predominant in the gut contents of sea urchins in fucoid beds, where their density was extremely low. Hemicentrotus pulcherrimus inhabit both fucoid beds and coralline flats. The main foods required for this sea urchin's gonad production are the dominant algae and sessile animals found in each algal community. The low amounts of fucoids in the gut contents of each species suggest low consumption, possibly because of difficulty in grazing fully grown and erect thalli and feeding deterrents.
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Chapter 21 Ecology of Strongylocentrotus nudus
Developments in Aquaculture and Fisheries Science, 2007Co-Authors: Yukio AgatsumaAbstract:Publisher Summary This chapter describes the ecology of Strongylocentrotus nudus ( S. nudus ). It is a dominant sea-urchin species in the northwest Pacific and is found on intertidal and subtidal rocky sea bottoms. The habitats of recruits and adults differ. They recruit onto coralline flats and migrate to kelp forests when one year old or greater. Somatic and gonadal growth is supported by brown macroalgae. S. nudus forms extremely high population densities that result in overgrazing. The gonadal development of the adults is classified into five stages: recovery, growth, prematuration, maturation, and spent. Its high growth rate, great longevity, high reproductive efforts, reproduction after a period of maximum feeding and growth responses to food availability, are the characteristics of a competitive species. The larvae of S. nudus appear during September and October, reaching a maximum density of hundreds to thousands of individuals per cubic meter. The amount of food intake differs with the type of algae and is greatly affected by secondary metabolites.
Shigeru Kawamata - One of the best experts on this subject based on the ideXlab platform.
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Experimental evaluation of the anti-attachment effect of microalgal mats on grazing activity of the sea urchin Strongylocentrotus nudus in oscillating flows
Journal of Experimental Biology, 2012Co-Authors: Shigeru KawamataAbstract:SUMMARY Algal mats can hinder the adhesion of the tube feet of sea urchins. This leads to the hypothesis that the restriction of sea urchin feeding activity by wave action can potentially be enhanced by the presence of algal mats, which will facilitate the survival of kelp recruits at sites with wave action in urchin barrens. To evaluate the potential anti-attachment effect of algal mats on sea urchins, a laboratory tank experiment was performed on the movement of Strongylocentrotus nudus sea urchins and their grazing on juvenile kelp plants at the center of 30×30 cm flat test substrates with or without a thin-layer microalgal mat at four levels of oscillatory flow (maximum orbital velocity: 10, 20, 30 and 40 cm s –1 ). The grazing loss of kelp slightly increased with increasing velocity up to 30 cm s –1 in the absence of microalgal mats, while in contrast the loss substantially decreased at 30 cm s –1 in their presence. Sea urchins were dislodged more frequently at 20 cm s –1 or higher velocities in the presence of microalgal mats. Mats were frequently abraded by scraping by the adoral spines during urchin movement at high velocities (30 and 40 cm s –1 ) but were subject to no or only slight urchin grazing in most cases. The results indicate that the overall decrease in grazing loss of kelp within the microalgal mats was attributable to the anti-attachment effect on urchins during incursions rather than due to urchins grazing on the mats.
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Climbing performance of sea urchin Strongylocentrotus nudus for upright, thin objects in wave-induced oscillatory flow
Fisheries Science, 2008Co-Authors: Shigeru KawamataAbstract:In order to examine the possibility of creating kelp beds with upright thin structures above sea urchin-dominated barrens, oscillating-flow-tank experiments were conducted on the climbing performance by the sea urchin Strongylocentrotus nudus using upright rods of two different diameters (3 and 10 mm) with five blade pieces of the kelp Eisenia bicyclis as algal food attached at 2.5-cm intervals in four levels of orbital velocities (0, 0.2, 0.3 and 0.4 m/s). In the absence of oscillatory flow urchins readily climbed to graze on food items in sequence from the bottom. The frequency of grazing up to the top food significantly decreased with velocity but no significant difference in the frequency was detected between the thin and thick rods. Fitting of a Markovian model with stationary transition probability to the observed frequency of the grazed height (number of pieces of food eaten from the bottom) suggested that, once climbing was initiated, an urchin continued to climb at a particular rate determined by the water motion. The resultant model predicted that, even with increasing height of upright rods, an orbital velocity higher than at least 0.1 m/s would be required to prevent urchin invasion in urchin-dominated barrens.
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Climbing performance of sea urchin Strongylocentrotus nudus for upright, thin objects in wave‐induced oscillatory flow
Fisheries Science, 2008Co-Authors: Shigeru KawamataAbstract:In order to examine the possibility of creating kelp beds with upright thin structures above sea urchin-dominated barrens, oscillating-flow-tank experiments were conducted on the climbing performance by the sea urchin Strongylocentrotus nudus using upright rods of two different diameters (3 and 10 mm) with five blade pieces of the kelp Eisenia bicyclis as algal food attached at 2.5-cm intervals in four levels of orbital velocities (0, 0.2, 0.3 and 0.4 m/s). In the absence of oscillatory flow urchins readily climbed to graze on food items in sequence from the bottom. The frequency of grazing up to the top food significantly decreased with velocity but no significant difference in the frequency was detected between the thin and thick rods. Fitting of a Markovian model with stationary transition probability to the observed frequency of the grazed height (number of pieces of food eaten from the bottom) suggested that, once climbing was initiated, an urchin continued to climb at a particular rate determined by the water motion. The resultant model predicted that, even with increasing height of upright rods, an orbital velocity higher than at least 0.1 m/s would be required to prevent urchin invasion in urchin-dominated barrens.
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effect of wave induced oscillatory flow on grazing by a subtidal sea urchin Strongylocentrotus nudus a agassiz
Journal of Experimental Marine Biology and Ecology, 1998Co-Authors: Shigeru KawamataAbstract:Oscillating-flow-tank experiments were conducted to evaluate the effect of wave-induced oscillatory flow on feeding by subtidal sea urchins Strongylocentrotus nudus (A. Agassiz). Feeding rates by two size groups (mean test diameter=53 and 80 mm) were measured for rehydrated dried blades and fresh live thalli of kelp Laminaria spp. Feeding rate of the larger sea urchins was markedly reduced at the peak velocity of 0.3 m/s and virtually ceased beyond ≈0.40 m/s. The peak velocities at which feeding rate began to decrease and reached almost nil were somewhat lower for the smaller sea urchins than for the larger ones. The velocity limit for feeding does not appear to be a function of temperature. Movement by sea urchins was reduced to half the rate in still water at the peak velocity of 0.30–0.40 m/s. Sea urchins could hardly move beyond 0.70 m/s. The depth variation in the mean of the wave-induced significant peak bottom water velocity, predicted from 6-yr offshore wave data available on the northeastern Pacific coast of Honshu, Japan, was consistent with depth distributions of S. nudus and kelp. The predicted frequency of the significant peak velocity <0.40 m/s, in which sea urchin grazing might be possible, was as high as 70% at 12 m depth but was only 3% at 2 m depth. Mirroring this, sea urchins were almost absent at 2 m depth and increased in density with increasing depth while the kelp decreased in density with increasing depth and were almost absent at 12 m depth.
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Effect of wave-induced oscillatory flow on grazing by a subtidal sea urchin Strongylocentrotus nudus (A. Agassiz)
Journal of Experimental Marine Biology and Ecology, 1998Co-Authors: Shigeru KawamataAbstract:Oscillating-flow-tank experiments were conducted to evaluate the effect of wave-induced oscillatory flow on feeding by subtidal sea urchins Strongylocentrotus nudus (A. Agassiz). Feeding rates by two size groups (mean test diameter=53 and 80 mm) were measured for rehydrated dried blades and fresh live thalli of kelp Laminaria spp. Feeding rate of the larger sea urchins was markedly reduced at the peak velocity of 0.3 m/s and virtually ceased beyond ≈0.40 m/s. The peak velocities at which feeding rate began to decrease and reached almost nil were somewhat lower for the smaller sea urchins than for the larger ones. The velocity limit for feeding does not appear to be a function of temperature. Movement by sea urchins was reduced to half the rate in still water at the peak velocity of 0.30–0.40 m/s. Sea urchins could hardly move beyond 0.70 m/s. The depth variation in the mean of the wave-induced significant peak bottom water velocity, predicted from 6-yr offshore wave data available on the northeastern Pacific coast of Honshu, Japan, was consistent with depth distributions of S. nudus and kelp. The predicted frequency of the significant peak velocity
Changlin Zhou - One of the best experts on this subject based on the ideXlab platform.
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A polysaccharide component from Strongylocentrotus nudus eggs inhibited hepatocellular carcinoma in mice by activating T lymphocytes.
Oncology letters, 2017Co-Authors: Min Zhang, Yang Liu, Hui Wang, Jie Dou, Changlin ZhouAbstract:A component purified from Strongylocentrotus nudus eggs on a diethylaminoethyl cellulose-52 chromatography column and eluted using a NaCl solution gradient (SEP-S), is a homogeneous polysaccharide of α-D-glucan with a reduced molecular weight of 9.33×105 Da, compared with that of S. nudus egg polysaccharide (SEP). In an in vivo antitumor assay of histocompatibility-22 hepatocellular carcinoma in tumor-bearing mice, the inhibitory rates at SEP-S doses of 5, 10 and 20 mg/kg/day were 38.8, 50.7 and 70.3%, respectively. In addition, the spleen and thymus indices and the percentages of cluster of differentiation (CD) 4+ and CD8+ T cells were significantly increased, and the activity of cytotoxic T lymphocytes was notably enhanced, suggesting that the anti-hepatocellular carcinoma activity is mediated by boosting the immune system. In vitro experiments also demonstrated that splenocyte proliferation induced by SEP-S was inhibited by the toll-like receptor (TLR) 2 and TLR4 monoclonal antibodies. These data indicate that SEP-S is a polysaccharide component possessing high anti-hepatocellular carcinoma activity and may be a potential immunotherapy candidate for the treatment of liver cancer.
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Effective inhibition of a Strongylocentrotus nudus eggs polysaccharide against hepatocellular carcinoma is mediated via immunoregulation in vivo
Immunology letters, 2011Co-Authors: Mengyu Wang, Hui Wang, Ying Tang, Jie Dou, Di Kang, Yu Gao, Changlin ZhouAbstract:This study was aimed at evaluating the inhibitory effect of a polysaccharide that was isolated from Strongylocentrotus nudus eggs (SEP) against hepatocellular carcinoma in H22-bearing mice and elucidating its immunological mechanisms by determining its effects on the growth of transplanted tumors and immune response in H22-bearing mice. ICR mice inoculated with mouse hepatoma carcinoma cell lines H22 were treated with SEP at doses of 4, 8, 16 mg/kg/d for 12 days. The effects of SEP were measured via the growth of the transplanted tumors, splenocyte proliferation, T lymphocytes counts, CTL activity, the production of cytokines from splenocytes and the levels of serum Ig in tumor-bearing mice. In addition, the effects of SEP on Erk phosphorylation in mouse splenocytes and on the transcriptional activity of NFAT in Jurkat T cells were also investigated. Our results showed that SEP significantly inhibited the growth of transplanted tumors in mice. SEP could not only remarkably enhance splenocyte proliferation, CD4(+) and CD8(+) T cell numbers as well as CTL activity, but it also elevated IL-2 and TNF-α secretion as well as IgA, IgM and IgG levels in the serum. Furthermore, the activation of Erk phosphorylation and the NFAT promoter by SEP promoted the transcription and expression of downstream gene IL-2. In conclusion, our study demonstrates that SEP effectively inhibits hepatocellular carcinoma in vivo via enhancement of host immune system function, and it could be a potential therapeutic drug for hepatocarcinoma.
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A polysaccharide from Strongylocentrotus nudus eggs protects against myelosuppression and immunosuppression in cyclophosphamide-treated mice.
International immunopharmacology, 2011Co-Authors: Hui Wang, Mengyu Wang, Jing Chen, Ying Tang, Jie Dou, Changlin ZhouAbstract:To assess the chemoprotective properties of a polysaccharide from Strongylocentrotus nudus eggs (SEP), myelosuppressed and immunosuppressed mouse models were generated by administration of cyclophosphamide (Cy) and then treated with SEP. SEP (16 mg/kg/d) remarkably increased spleen and thymus indices, activated the proliferation of leukocytes and erythrocytes and platelets from peripheral blood, and exhibited co-mitogenic activity on ConA- or LPS-stimulated splenocytes in a dose-dependent manner. An increased percentage of CD34(+) cells in bone marrow of Cy-treated mice was also observed. Furthermore, SEP elevated CD4(+) T lymphocyte counts as well as the CD4/CD8 ratio dose-dependently, and it increased interleukin-2 (IL-2), IgA, IgM, and IgG levels in the sera of Cy-treated mice. Pre-incubation with TLR2 and TLR4 blocking antibodies inhibited splenocyte proliferation and its IL-2 secretion. Finally, SEP significantly induced Akt phosphorylation in splenocytes from Cy-treated mice, suggesting that chemoprotection by SEP was mediated through the PI3K/Akt signaling pathway. These findings indicate that SEP plays an important role in the protection against myelosuppression and immunosuppression in Cy-treated mice and could be a potential immunomodulatory agent.
