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Sample records for ascidian halocynthia roretzi

  1. Disinfection of fertilized eggs of the edible ascidian Halocynthia roretzi for prevention of soft tunic syndrome.

    PubMed

    Kumagai, Akira; Tanabe, Toru; Nawata, Akatsuki; Suto, Atsushi

    2016-02-25

    Azumiobodo hoyamushi, the causative agent of soft tunic syndrome, was likely introduced to farming sites of the edible ascidian Halocynthia roretzi via ascidian spat. The source of infection is thought to be cysts of A. hoyamushi that reside in the substrates on which the ascidian spat are attached, but not the spat themselves. Thus, there is a need to develop methods to prevent contamination of the substrates with A. hoyamushi during seed production of the ascidian. We evaluated the protozoacidal effects of sodium hypochlorite and povidone-iodine against the flagellate and temporary cyst forms of A. hoyamushi. Additionally, we evaluated the effects of these disinfectants on the development of fertilized ascidian eggs. The flagellate form of A. hoyamushi was completely inactivated by povidone-iodine (5 ppm, 1 min) and sodium hypochlorite (1 ppm, 1 min). The temporary cysts of A. hoyamushi were completely inactivated by both disinfectants (5 ppm, 1 min). Disinfection with 50 ppm povidone-iodine for 15 min or 5 ppm sodium hypochlorite for 15 min had no effect on ascidian embryogenesis. Thus, horizontal transmission of A. hoyamushi via the substrates can be efficiently prevented by disinfecting ascidian eggs or tools used for spawning with povidone-iodine baths ranging from 5 ppm for 1 min to 50 ppm for 15 min without any side effects. PMID:26912045

  2. Wnt5 is required for notochord cell intercalation in the ascidian Halocynthia roretzi

    PubMed Central

    Niwano, Tomoko; Takatori, Naohito; Kumano, Gaku; Nishida, Hiroki

    2009-01-01

    Background information. In the embryos of various animals, the body elongates after gastrulation by morphogenetic movements involving convergent extension. The Wnt/PCP (planar cell polarity) pathway plays roles in this process, particularly mediolateral polarization and intercalation of the embryonic cells. In ascidians, several factors in this pathway, including Wnt5, have been identified and found to be involved in the intercalation process of notochord cells. Results. In the present study, the role of the Wnt5 genes, Hr-Wnt5α (Halocynthia roretzi Wnt5α) and Hr-Wnt5β, in convergent extension was investigated in the ascidian H. roretzi by injecting antisense oligonucleotides and mRNAs into single precursor blastomeres of various tissues, including notochord, at the 64-cell stage. Hr-Wnt5α is expressed in developing notochord and was essential for notochord morphogenesis. Precise quantitative control of its expression level was crucial for proper cell intercalation. Overexpression of Wnt5 proteins in notochord and other tissues that surround the notochord indicated that Wnt5α plays a role within the notochord, and is unlikely to be the source of polarizing cues arising outside the notochord. Detailed mosaic analysis of the behaviour of individual notochord cells overexpressing Wnt5α indicated that a Wnt5α-manipulated cell does not affect the behaviour of neighbouring notochord cells, suggesting that Wnt5α works in a cell-autonomous manner. This is further supported by comparison of the results of Wnt5α and Dsh (Dishevelled) knockdown experiments. In addition, our results suggest that the Wnt/PCP pathway is also involved in mediolateral intercalation of cells of the ventral row of the nerve cord (floor plate) and the endodermal strand. Conclusion. The present study highlights the role of the Wnt5α signal in notochord convergent extension movements in ascidian embryos. Our results raise the novel possibility that Wnt5α functions in a cell-autonomous manner

  3. Cellulose is not degraded in the tunic of the edible ascidian Halocynthia roretzi contracting soft tunic syndrome.

    PubMed

    Kimura, Satoshi; Nakayama, Kei; Wada, Masahisa; Kim, Ung-Jin; Azumi, Kaoru; Ojima, Takao; Nozawa, Akino; Kitamura, Shin-Ichi; Hirose, Euichi

    2015-10-16

    Soft tunic syndrome is a fatal disease in the edible ascidian Halocynthia roretzi, causing serious damage to ascidian aquaculture in Korea and Japan. In diseased individuals, the tunic, an integumentary extracellular matrix of ascidians, softens and eventually tears. This is an infectious disease caused by the kinetoplastid flagellate Azumiobodo hoyamushi. However, the mechanism of tunic softening remains unknown. Because cellulose fibrils are the main component of the tunic, we compared the contents and structures of cellulose in healthy and diseased tunics by means of biochemical quantification and X-ray diffractometry. Unexpectedly, the cellulose contents and structures of cellulose microfibrils were almost the same regardless of the presence or absence of the disease. Therefore, it is unlikely that thinning of the microfibrils occurred in the softened tunic, because digestion should have resulted in decreases in crystallinity index and crystallite size. Moreover, cellulase was not detected in pure cultures of A. hoyamushi in biochemical and expressed sequence tag analyses. These results indicate that cellulose degradation does not occur in the softened tunic. PMID:26480917

  4. Vascular Endothelial Growth Factor Receptor Family in Ascidians, Halocynthia roretzi (Sea Squirt). Its High Expression in Circulatory System-Containing Tissues.

    PubMed

    Samarghandian, Saeed; Shibuya, Masabumi

    2013-01-01

    The vascular endothelial growth factor (VEGF)-VEGF Receptor (VEGFR) system is an important pathway for regulation of angiogenesis. However, its evolutionary development, particularly the step from invertebrates to vertebrates, is still largely unknown. Here, we molecularly cloned the VEGFR-like gene from Halocynthia roretzi, a species belonging to the Tunicata, the chordate subphylum recently considered the sister group of vertebrates. The cDNA encoded a homolog of human VEGFR, including the transmembrane domain, and the tyrosine kinase domain with a kinase-insert region, which was designated S. sq VEGFR (GenBank AB374180). Similar to Tunicates including ascidians in the phylogenetic tree, the Amphioxus, another chordate, is located close to vertebrates. However, S. sq VEGFR has a higher homology than the Amphioxus VEGFR-like molecule (GenBank AB025557) to human VEGFR in the kinase domain-2 region. The S. sq VEGFR mRNA was expressed at highest levels in circulatory system-containing tissues, suggesting that S. sq VEGFR plays an important role in the formation or maintenance of circulatory system in Tunicates, Halocynthia roretzi. PMID:23455462

  5. In vitro and in vivo efficacy of drugs against the protozoan parasite Azumiobodo hoyamushi that causes soft tunic syndrome in the edible ascidian Halocynthia roretzi (Drasche).

    PubMed

    Park, K H; Zeon, S-R; Lee, J-G; Choi, S-H; Shin, Y K; Park, K-I

    2014-04-01

    It was discovered recently that infection by a protozoan parasite, Azumiobodo hoyamushi, is the most probable cause for soft tunic syndrome in an edible ascidian, Halocynthia roretzi (Drasche). In an attempt to develop measures to eradicate the causative parasite, various drugs were tested for efficacy in vitro and in vivo. Of the 20 antiprotozoal drugs having different action mechanisms, five were found potent (24-h EC50  < 10 mg L(-1) ) in their parasite-killing effects: formalin, H2 O2 , bithionol, ClO2 and bronopol. Moderately potent drugs (10 < 24-h EC50  < 100 mg L(-1) ) were quinine, fumagillin, amphotericin B, ketoconazole, povidone-iodine, chloramine-T and benzalkonium chloride. Seven compounds, metronidazole, albendazole, paromomycin, nalidixic acid, sulfamonomethoxine, KMnO4 , potassium monopersulphate and citric acid, exhibited EC50  > 100 mg L(-1) . When ascidians were artificially infected with A. hoyamushi, treated using 40 mg L(-1) formalin, bronopol, ClO2 , or H2 O2 for 1 h and then monitored for 24 h, very low mortality was observed. However, the number of surviving parasite cells in the ascidian tunic tissues was significantly reduced by treating with 40 mg L(-1) formalin or ClO2 for 1 h. The data suggest that we might be able to develop a disinfection measure using a treatment regimen involving commonly available drugs. PMID:23952334

  6. Ascidian bioresources: common and variant chemical compositions and exploitation strategy - examples of Halocynthia roretzi, Styela plicata, Ascidia sp. and Ciona intestinalis.

    PubMed

    Zhao, Yadong; Li, Jiebing

    2016-01-01

    To explore abundant marine ascidian bioresources, four species from two orders have been compared in their chemical compositions. After a universal separation of the animal body into two fractions, all tunics have been found rich in carbohydrate contents, while all inner body tissues are richer in proteins. Cellulose is present almost exclusively in the tunics and more in the order Stolidobranchia, while more sulfated polysaccharides are present in Phlebobranchia species. Almost all proteins are collagens with a high essential amino acid index and high delicious amino acid (DAA) content. All fractions also have high contents of good-quality fatty acids and trace minerals but low toxic element contents, with different sterols and glycosaminoglycans. There are species-specific characteristics observed for vanadium accumulation and sterol structures which are also meaningful for ascidian chemotaxonomy and resource exploitation. It is suggested that in addition to the present utilizations of tunics for cellulose production and of some species' inner body tissues as human food, one should explore all species' inner body tissues as human foods and all tunics as food or animal feed with the contained cellulose as dietary fiber. Collagens, sulfated polysaccharides, glycosaminoglycans, sterols and trace elements could be explored as byproducts for, e.g. pharmaceutical and chemical industries. PMID:27049617

  7. Ruegeria halocynthiae sp. nov., isolated from the sea squirt Halocynthia roretzi.

    PubMed

    Kim, Young-Ok; Park, Sooyeon; Nam, Bo-Hye; Kang, So-Jung; Hur, Young Baek; Lee, Sang-Jun; Oh, Tae-Kwang; Yoon, Jung-Hoon

    2012-04-01

    A Gram-negative, non-motile, rod-shaped bacterial strain, designated MA1-6T, was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea, and was characterized to determine its taxonomic position. Strain MA1-6T grew optimally at pH 7.0-8.0, at 30 °C and in the presence of 2-3 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain MA1-6T fell within the clade comprising Ruegeria species and exhibited 95.3-96.5 % similarity to the type strains of recognized Ruegeria species. Strain MA1-6T contained Q-10 as the predominant ubiquinone and C18:1ω7c as the major fatty acid, which is consistent with data for Ruegeria species. The major polar lipids detected in strain MA1-6T and Ruegeria atlantica KCTC 12424T were phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and an unidentified lipid. The DNA G+C content of strain MA1-6T was 58.6 mol%. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain MA1-6T can be distinguished from recognized Ruegeria species. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain MA1-6T is considered to represent a novel species of the genus Ruegeria, for which the name Ruegeria halocynthiae sp. nov. is proposed; the type strain is MA1-6T (=KCTC 23463T=CCUG 60744T). PMID:21669923

  8. Roseovarius halocynthiae sp. nov., isolated from the sea squirt Halocynthia roretzi.

    PubMed

    Kim, Young-Ok; Kong, Hee Jeong; Park, Sooyeon; Kang, So-Jung; Kim, Woo-Jin; Kim, Kyung-Kil; Oh, Tae-Kwang; Yoon, Jung-Hoon

    2012-04-01

    A Gram-negative, motile, ovoid- to rod-shaped bacterial strain, designated MA1-10T, was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea. Strain MA1-10T grew optimally at pH 7.0-8.0, at 30 °C and in the presence of 2 % (w/v) NaCl. In the neighbour-joining phylogenetic tree based on 16S rRNA gene sequences, strain MA1-10T clustered with Roseovarius crassostreae CV919-312T, with which it exhibited 97.1 % sequence similarity, at a bootstrap resampling value of 96.2 %. It exhibited 93.3-95.8 % 16S rRNA gene sequence similarity to the type strains of other recognized Roseovarius species. Strain MA1-10T contained Q-10 as the predominant ubiquinone and C18:1ω7c as the major fatty acid, which is consistent with data for the genus Roseovarius. The major polar lipids were phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, an unidentified aminolipid and an unidentified lipid. The DNA G+C content of strain MA1-10T was 55.4 mol%. Mean DNA-DNA relatedness between strain MA1-10T and R. crassostreae DSM 16950T was 13 %. Differential phenotypic properties, together with phylogenetic and genetic distinctiveness, demonstrated that strain MA1-10T could be distinguished from all recognized Roseovarius species. On the basis of the data presented, strain MA1-10T is considered to represent a novel species of the genus Roseovarius, for which the name Roseovarius halocynthiae sp. nov. is proposed; the type strain is MA1-10T (=KCTC 23462T=CCUG 60745T). PMID:21669917

  9. Tenacibaculum halocynthiae sp. nov., a member of the family Flavobacteriaceae isolated from sea squirt Halocynthia roretzi.

    PubMed

    Kim, Young-Ok; Park, Sooyeon; Nam, Bo-Hye; Jung, Yong-Taek; Kim, Dong-Gyun; Jee, Young-Ju; Yoon, Jung-Hoon

    2013-06-01

    A Gram-negative, non-spore-forming, aerobic, non-flagellated, non-gliding and rod-shaped bacterial strain, designated P-R2A1-2(T), was isolated from sea squirt (Halocynthia roretzi) collected from the South Sea, Korea. It grew optimally at 25-28 °C, at pH 7.0-8.0 and in the presence of 2 % (w/v) NaCl. Neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that the strain fell within the clade comprising Tenacibaculum species. Strain P-R2A1-2(T) exhibited the highest 16S rRNA gene sequence similarity values of 97.6, 97.2 and 97.0 % to Tenacibaculum aestuarii SMK-4(T), T. lutimaris TF-26(T) and T. aiptasiae a4(T), respectively, and of 94.5-96.8 % to the type strains of the other Tenacibaculum species. Strain P-R2A1-2(T) contained MK-6 as the predominant menaquinone and C16:1 ω7c and/or iso-C15:0 2-OH, iso-C15:0 3-OH and iso-C15:0 as the major fatty acids. The DNA G + C content of strain P-R2A1-2(T) was 30.7 mol % and its DNA-DNA relatedness values with the type strains of T. aestuarii, T. lutimaris and T. aiptasiae were 17 ± 4.2, 21 ± 6.1 and 16 ± 5.2 %, respectively. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that the novel strain is separate from other Tenacibaculum species. On the basis of the data presented, strain P-R2A1-2(T) is considered to represent a novel species of the genus Tenacibaculum, for which the name Tenacibaculum halocynthiae sp. nov. is proposed. The type strain is P-R2A1-2(T) (=KCTC 32262(T )= CCUG 63681(T)). PMID:23543245

  10. Litoreibacter halocynthiae sp. nov., isolated from the sea squirt Halocynthia roretzi.

    PubMed

    Kim, Young-Ok; Park, Sooyeon; Nam, Bo-Hye; Jung, Yong-Taek; Kim, Dong-Gyun; Lee, Jung-Sook; Lee, Sang-Jun; Yoon, Jung-Hoon

    2013-09-01

    A Gram-stain-negative, non-motile and coccoid, ovoid or rod-shaped bacterial strain, designated P-MA1-7(T), was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea. Strain P-MA1-7(T) grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2-3% (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain P-MA1-7(T) fell within the cluster comprising the type strains of four species of the genus Litoreibacter, exhibiting 16S rRNA gene sequence similarity values of 97.0-98.5% to these four type strains and less than 95.9% sequence similarity to the strains of the other species examined. Strain P-MA1-7(T) contained Q-10 as the predominant ubiquinone and C(18:1)ω7c as the predominant fatty acid. The major polar lipids of strain P-MA1-7(T) were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminolipid and one unidentified lipid. The DNA G+C content of strain P-MA1-7(T) was 58.3 mol% and DNA-DNA relatedness values of strain P-MA1-7(T) with the type strains of the four species of the genus Litoreibacter were in the range of 8-21%. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain P-MA1-7(T) was separate from other species of the genus Litoreibacter. On the basis of these data, strain P-MA1-7(T) is considered to represent a novel species of the genus Litoreibacter, for which the name Litoreibacter halocynthiae sp. nov. is proposed. The type strain is P-MA1-7(T) ( =KCTC 32213(T) =CCUG 63416(T)). PMID:23524350

  11. Nucleotide sequences of 5S rRNAs from sponge Halichondria japonica and tunicate Halocynthia roretzi and their phylogenetic positions

    PubMed Central

    Komiya, Hiroyuki; Hasegawa, Masami; Takemura, Shosuke

    1983-01-01

    The nucleotide sequences of 5S rRNAs from sponge Halichondria japonica and tunicate Halocynthia roretzi were determined by chemical and enzymatic gel methods. Their phylogenetic positions among metazoans were derived from the 5S rRNA sequences by a computer analysis based on the maximum parsimony principle. It was suggested that the sponge is closely related to several invertebrates and the tunicate has affinity to vertebrates rather than invertebrates. PMID:6835845

  12. Effects of sea squirt (Halocynthia roretzi) lipids on white adipose tissue weight and blood glucose in diabetic/obese KK-Ay mice.

    PubMed

    Mikami, Nana; Hosokawa, Masashi; Miyashita, Kazuo

    2010-01-01

    Lipids extracted from Halocynthia roretzi contain n-3 polyunsaturated fatty acids such as eicosapentaenoic acid and docosahexaenoic acid, as well as carotenoids. The aim of the present study was to evaluate the effect of H. roretzi lipids on white adipose tissue (WAT) weight and high blood glucose levels in diabetic/obese KK-Ay mice. H. roretzi lipids were fed to the diabetic/obese KK-Ay mice for 5 weeks. In the mice treated with the H. roretzi lipids compared to control mice, WAT weight was reduced, blood glucose levels and leptin mRNA expression in the epididymal WAT were significantly decreased, serum leptin levels also tended to decrease, and serum adiponectin levels tended to increase. These results demonstrate that H. roretzi lipids have beneficial health effects on diabetic/obese KK-Ay mice. PMID:21472260

  13. Colwellia meonggei sp. nov., a novel gammaproteobacterium isolated from sea squirt Halocynthia roretzi.

    PubMed

    Kim, Young-Ok; Park, Sooyeon; Nam, Bo-Hye; Jung, Yong-Taek; Kim, Dong-Gyun; Yoon, Jung-Hoon

    2013-12-01

    A Gram-negative, non-spore-forming, aerobic, motile and rod-shaped or ovoid bacterial strain, designated MA1-3(T), was isolated from a sea squirt (Halocynthia roretzi) collected from the South sea in South Korea. Strain MA1-3(T) was found to grow optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences revealed that strain MA1-3(T) fell within the clade comprising Colwellia species, clustering coherently with the type strains of Colwellia aestuarii, Colwellia polaris and Colwellia chukchiensis, showing sequence similarity values of 97.2, 96.4 and 95.6 %, respectively. It exhibited 16S rRNA gene sequence similarity values of 93.9-96.1 % to the type strains of the other Colwellia species. Strain MA1-3(T) was found to contain Q-8 as the predominant ubiquinone and C16:1 ω7c and/or C16:1 ω6c, C16:0 and C16:1 ω9c as the major fatty acids. The DNA G+C content of strain MA1-3(T) was determined to be 39.1 mol% and its mean DNA-DNA relatedness value with the type strain of C. aestuarii was 13 ± 5.4 %. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that the novel strain is separated from other Colwellia species. On the basis of the data presented, strain MA1-3(T) is considered to represent a novel species of the genus Colwellia, for which the name Colwellia meonggei sp. nov. is proposed. The type strain is MA1-3(T) (=KCTC 32380(T) = CECT 8302(T)). PMID:24006188

  14. Halocynthiibacter namhaensis gen. nov., sp. nov., a novel alphaproteobacterium isolated from sea squirt Halocynthia roretzi.

    PubMed

    Kim, Young-Ok; Park, Sooyeon; Kim, Hyangmi; Park, Doo-Sang; Nam, Bo-Hye; Kim, Dong-Gyun; Yoon, Jung-Hoon

    2014-05-01

    A Gram-negative, non-motile and rod-shaped bacterial strain, designated RA2-3(T), was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea, and its taxonomic position was investigated by using a polyphasic approach. Strain RA2-3(T) was observed to grow optimally at 25 °C, at pH 7.0-7.5 and in the presence of 2 % (w/v) NaCl. Strain RA2-3(T) exhibited the highest 16S rRNA gene sequence similarity values to the type strains of Litoreibacter meonggei (95.7 %), Planktotalea frisia (95.6 %), Thalassobius gelatinovorus (95.5 %) and Pelagicola litoralis (95.4 %). A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain RA2-3(T) clustered with the type strains of Planktotalea frisia, Pelagicola litoralis, Pacificibacter maritimus and Roseovarius marinus. Strain RA2-3(T) was found to contain Q-10 as the predominant ubiquinone and C18:1 ω7c as the major fatty acid. The major polar lipids detected in strain RA2-3(T) were phosphatidylcholine, phosphatidylglycerol, one unidentified aminolipid and one unidentified lipid. The DNA G+C content of strain RA2-3(T) was 52.9 mol%. On the basis of the phylogenetic, chemotaxonomic and phenotypic properties, strain RA2-3(T) is considered to represent a new genus and species within the family Rhodobacteraceae, for which the name Halocynthiibacter namhaensis gen. nov., sp. nov. is proposed. The type strain of H. namhaensis is RA2-3(T) (=KCTC 32362(T)=NBRC 109999(T)). PMID:24573327

  15. Pseudopelagicola gijangensis gen. nov., sp. nov., isolated from the sea squirt Halocynthia roretzi.

    PubMed

    Kim, Young-Ok; Park, Sooyeon; Nam, Bo-Hye; Kim, Dong-Gyun; Yoon, Jung-Hoon

    2014-10-01

    A Gram-stain-negative, aerobic, non-motile, rod-shaped bacterial strain, designated YSS-7(T), was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea of South Korea. Strain YSS-7(T) grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2.0% (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences revealed that strain YSS-7(T) clustered with the type strains of Pelagicola litoralis, Planktotalea frisia, Pacificibacter maritimus and Roseovarius marinus. Strain YSS-7(T) exhibited the highest 16S rRNA gene sequence similarity (97.7%) to the type strain of Pelagicola litoralis and sequence similarity of more than 96.0% to the type strains of some other species. Strain YSS-7(T) contained Q-10 as the predominant ubiquinone and C18:1ω7c and 11-methyl C18:1ω7c as the major fatty acids. The major polar lipids of strain YSS-7(T) were phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and an unidentified lipid. The fatty acid and polar lipid profiles of strain YSS-7(T) were different from those of the type strains of phylogenetically related species. The DNA G+C content of strain YSS-7(T) was 55.5 mol%. Other phenotypic properties demonstrated that strain YSS-7(T) is distinguished from phylogenetically related species. On the basis of the data presented, strain YSS-7(T) is considered to represent a novel genus and species, for which the name Pseudopelagicola gijangensis gen. nov., sp. nov. is proposed. The type strain of Pseudopelagicola gijangensis is YSS-7(T) ( = KCTC 42049(T) = CECT 8540(T)). PMID:25048211

  16. Octadecabacter ascidiaceicola sp. nov., isolated from a sea squirt (Halocynthia roretzi).

    PubMed

    Kim, Young-Ok; Park, In-Suk; Park, Sooyeon; Nam, Bo-Hye; Park, Ji-Min; Kim, Dong-Gyun; Yoon, Jung-Hoon

    2016-01-01

    A Gram-stain-negative, non-spore-forming, non-flagellated and coccoid, ovoid or rod-shaped bacterial strain, RA1-3T, was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, South Korea, and subjected to a taxonomic study using a polyphasic approach. Strain RA1-3T grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2.0-3.0 % (w/v) NaCl. Neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences revealed that strain RA1-3T clustered with the type strains of three species of the genus Octadecabacter, showing 97.54-98.41 % 16S rRNA gene sequence similarity. Sequence similarities to other recognized species were less than 96.97 %. Strain RA1-3T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c as the major fatty acid. The major polar lipids of strain RA1-3T were phosphatidylcholine, phosphatidylglycerol, one unidentified aminolipid and one unidentified lipid. The DNA G+C content of strain RA1-3T was 56 mol% and DNA-DNA relatedness values with the type strains of Octadecabacter temperatus, Octadecabacter antarcticus and Octadecabacter arcticus were 13-24 %. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain RA1-3T is separated from other recognized species of the genus Octadecabacter. On the basis of the data presented, strain RA1-3T is considered to represent a novel species of the genus Octadecabacter, for which the name Octadecabacter ascidiaceicola sp. nov. is proposed. The type strain is RA1-3T ( = KCTC 42605T = CECT 8868T). PMID:26508418

  17. [APPLICATION OF FLOW CYTOMETRY FOR THE ANALYSIS OF CIRCULATING HEMOCYTE POPULATIONS IN THE ASCIDIAN HALOCYNTHIA AURANTIUM (PALLAS, 1787)].

    PubMed

    Sukhachev, A N; Dyachkov, I S; Kudryavtsev, I V; Kumeiko, V V; Tsybulskiy, A V; Polevshchikov, A V

    2015-01-01

    This study addresses the potentialities of flow cytometry in analyzing the composition of circulating hemocyte populations in the ascidian Halocynthia aurantium (Pallas, 1787) both using monoclonal antibodies (mAbs) against some human leukocyte conservative adhesion molecules and without mAbs. Flow cytometry, based on the assessment of forward and side scattering revealed five hemocyte populations. From the wide panel of antibodies against human leukocyte adhesion molecules (CD15, CD29, CD34, CD54, CD62L, CD62P, CD90, CD94, CD117, CD 166), only two mAbs (against CD54, CD90) displayed cross-reactivity with the H. aurantium hemocyte surface antigens. Distribution patterns of these antigens across the hemocyte populations have been analyzed. PMID:26281224

  18. Influence of sea squirt (Halocynthia roretzi) aquaculture on benthic-pelagic coupling in coastal waters: A study of the South Sea in Korea

    NASA Astrophysics Data System (ADS)

    Lee, Jae Seong; Kim, Sung-Han; Kim, Yong-Tae; Hong, Sok Jin; Han, Jeong Hee; Hyun, Jung-Ho; Shin, Kyung-Hoon

    2012-03-01

    The influence of sea squirt aquaculture on benthic-pelagic coupling was evaluated in semi-enclosed Korean coastal waters with an in situ benthic chamber and results show for the first time that suspended sea squirt cultures play an important role in benthic-pelagic coupling in the coastal zone. Measurements of primary production, vertical particulate fluxes, and benthic fluxes were made at two stations, a sea squirt (Halocynthia roretzi) farm (SSF) and an area of organic-matter-enriched sediment in Jinhae Bay. The vertical material fluxes of organic carbon, nitrogen, and biogenic silicate (BSi) were significantly higher at SSF than in Jinhae Bay, indicating massive biodeposits in the surface sediments at SSF. The organic carbon oxidation rates (Cox) were estimated after correction for CaCO3 dissolution. The average Cox at SSF (204 mmol C m-2 d-1) was significantly higher than that in the organic-enriched Jinhae Bay sediment (77 mmol C m-2 d-1). The organic carbon burial fluxes were determined using vertical profiles of organic carbon of up to 30 cm and the sedimentation rate calculated from the excess 210Pb distribution. At both stations, ˜95% of the settled organic carbon was oxidized and only ˜5% was buried in the deep sediment layer. The benthic fluxes of dissolved inorganic nitrogen and phosphate at SSF were 2-12 times higher than in Jinhae Bay, corresponding to 85%, and 270%, respectively, of the requirements for primary production.

  19. The kinetoplastid parasite Azumiobodo hoyamushi, the causative agent of soft tunic syndrome of the sea squirt Halocynthia roretzi, resides in the East Sea of Korea.

    PubMed

    Kim, Hyoun-Joong; Park, Jong Soo; Park, Kwan Ha; Shin, Yun-Kyung; Park, Kyung-Il

    2014-02-01

    Mass mortality of the edible sea squirt Halocynthia roretzi since the 1990s in the southern and eastern seas of Korea has caused large economic losses. The disease is characterized by symptoms of initially softened and thinned tunics that eventually rupture. Thus, the disease is called soft tunic syndrome (STS); however, the causative agent in these regions is unknown. In the present study, two kinetoplastid organisms were isolated from STS sea squirts collected from culture farms in Tongyeong located in the East Sea of Korea. Phylogenetic analysis of 18S rRNA sequences identified these organisms as Azumiobodo hoyamushi and Procryptobia sorokini. These kinetoplastids were injected into healthy sea squirts and cultured at 15°C for 13days. Sea squirts injected with A. hoyamushi showed 100% STS whereas, P. sorokini did not induce disease, thereby confirming A. hoyamushi as the causative agent of STS. A. hoyamushi flourishes in vitro at 10-15°C, and dies at temperatures below 5°C or above 20°C. The optimum salinity level for growth is 30-35psu, and death occurs below 25psu. These optima coincide with marine temperature and salinity levels between March and June on the southern coasts of Korea, the period when the syndrome occurs at the highest frequency. The identification here of A. hoyamushi as the causative agent of STS and our findings regarding its optimum growth conditions should lead to methods for reducing the incidence of STS. PMID:24389332

  20. Description of Litoreibacter meonggei sp. nov., isolated from the sea squirt Halocynthia roretzi, reclassification of Thalassobacter arenae as Litoreibacter arenae comb. nov. and emended description of the genus Litoreibacter Romanenko et al. 2011.

    PubMed

    Kim, Young-Ok; Park, Sooyeon; Nam, Bo-Hye; Kang, So-Jung; Hur, Young-Baek; Kim, Dong-Gyun; Oh, Tae-Kwang; Yoon, Jung-Hoon

    2012-08-01

    A Gram-negative, non-motile and coccoid, ovoid or rod-shaped bacterial strain, designated MA1-1(T), was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain MA1-1(T) is phylogenetically closely related to Litoreibacter species and to Thalassobacter arenae. It exhibited 16S rRNA gene sequence similarities of 97.3, 97.1 and 97.3% to the type strains of Litoreibacter albidus, Litoreibacter janthinus and T. arenae, respectively. Strain MA1-1(T) contained Q-10 as the predominant ubiquinone and C(18:1)ω7c as the predominant fatty acid. The polar lipid profile of strain MA1-1(T) was similar to those of the type strains of L. albidus and L. janthinus. T. arenae was found to be phylogenetically and chemotaxonomically more closely related to Litoreibacter species and strain MA1-1(T) than to Thalassobacter stenotrophicus, the type species of the genus Thalassobacter. The DNA G+C content of strain MA1-1(T) was 57.9 mol%, and DNA-DNA relatedness to the type strains of the two Litoreibacter species and T. arenae was 9-14%. Differential phenotypic properties, together with the observed phylogenetic and genetic distinctiveness, distinguished strain MA1-1(T) from the two Litoreibacter species and T. arenae. On the basis of the data presented, strain MA1-1(T) is considered to represent a novel species of the genus Litoreibacter, for which the name Litoreibacter meonggei sp. nov. is proposed. The type strain is MA1-1(T) ( = KCTC 23699(T)  = CCUG 61486(T)). In this study, it is also proposed that Thalassobacter arenae is reclassified as a member of the genus Litoreibacter, Litoreibacter arenae comb. nov. (type strain GA2-M15(T)  = DSM 19593(T)  = KACC 12675(T)). An emended description of the genus Litoreibacter is also presented. PMID:21984668

  1. RNA-Seq-Based Metatranscriptomic and Microscopic Investigation Reveals Novel Metalloproteases of Neobodo sp. as Potential Virulence Factors for Soft Tunic Syndrome in Halocynthia roretzi

    PubMed Central

    Jang, Ho Bin; Kim, Young Kyu; del Castillo, Carmelo S.; Nho, Seong Won; Cha, In Seok; Park, Seong Bin; Ha, Mi Ae; Hikima, Jun-ichi; Hong, Sung Jong; Aoki, Takashi; Jung, Tae Sung

    2012-01-01

    Bodonids and trypanosomatids are derived from a common ancestor with the bodonids being a more primitive lineage. The Neobodonida, one of the three clades of bodonids, can be free-living, commensal or parasitic. Despite the ecological and evolutionary significance of these organisms, however, many of their biological and pathological features are currently unknown. Here, we employed metatranscriptomics using RNA-seq technology combined with field-emission microscopy to reveal the virulence factors of a recently described genus of Neobodonida that is considered to be responsible for ascidian soft tunic syndrome (AsSTS), but whose pathogenesis is unclear. Our microscopic observation of infected tunic tissues suggested putative virulence factors, enabling us to extract novel candidate transcripts; these included cysteine proteases of the families C1 and C2, serine proteases of S51 and S9 families, and metalloproteases grouped into families M1, M3, M8, M14, M16, M17, M24, M41, and M49. Protease activity/inhibition assays and the estimation of expression levels within gene clusters allowed us to identify metalloprotease-like enzymes as potential virulence attributes for AsSTS. Furthermore, a multimarker-based phylogenetic analysis using 1,184 concatenated amino acid sequences clarified the order Neobodo sp. In sum, we herein used metatranscriptomics to elucidate the in situ expression profiles of uncharacterized putative transcripts of Neobodo sp., combined these results with microscopic observation to select candidate genes relevant to pathogenesis, and used empirical screening to define important virulence factors. PMID:23300657

  2. Azumiobodo hoyamushi, the kinetoplastid causing soft tunic syndrome in ascidians, may invade through the siphon wall.

    PubMed

    Hirose, Euichi; Kumagai, Akira; Nawata, Akatsuki; Kitamura, Shin-Ichi

    2014-07-01

    The infectious kinetoplastid Azumiobodo hoyamushi causes 'soft tunic syndrome', a serious problem in aquaculture of the edible ascidian Halocynthia roretzi. Infection tests using diseased tunics demonstrated that juvenile (0.8 yr old) individuals never developed soft tunic syndrome, but all individuals in the other age groups (1.8, 2.8, and 3.8 yr old) showed the disease symptoms. In the infection tests, tunic softening was first observed at the tunic around siphons. Based on ultrastructural observation of the inner wall of the branchial siphon, the tunic lining the inner wall in juveniles (0.5 yr old) was completely covered with cuticle, which had a dense structure to prevent bacterial and protist invasion. In contrast, the tunic was often partly damaged and not covered with cuticle in healthy adults (≥2.5 yr old). The damaged tunic in the siphon wall could be an entrance for A. hoyamushi into the tunic of adult hosts. PMID:24991851

  3. Encystment and excystment of kinetoplastid Azumiobodo hoyamushi, causal agent of soft tunic syndrome in ascidian aquaculture.

    PubMed

    Nawata, Akatsuki; Hirose, Euichi; Kitamura, Shin-Ichi; Kumagai, Akira

    2015-08-20

    Soft tunic syndrome in the edible ascidian Halocynthia roretzi is caused by the kinetoplastid flagellate Azumiobodo hoyamushi, which was found to assume a fusiform cell form with 2 flagella in axenic, pure culture. When the flagellate form was incubated in sterilized artificial seawater (pH 8.4), some of the cells became cyst-like and adhered to the bottom of the culture plate. The cyst-like forms were spherical or cuboidal, and each had 2 flagella encapsulated in its cytoplasm. Encystment was also induced in culture medium alkalified to the pH of seawater (8.4) but not in unmodified (pH 7.2) or acidified media (pH 6.4). More than 95% of the cyst-like cells converted to the flagellate form within 1 d following transfer to seawater containing ascidian tunic extracts from host ascidians. The cyst-like cells were able to survive in seawater with no added nutrients for up to 2 wk at 20°C and for a few months at 5 to 15°C. The survival period in seawater depended on temperature: some cyst-like cells survived 3 mo at 10°C, and ca. 95% of these converted to flagellate forms in seawater containing tunic extracts. Thus, A. hoyamushi is able to persist under adverse conditions in a cyst-like form able to adhere to organic and inorganic substrata for protracted periods of time. PMID:26290510

  4. An extra tRNAGly(U*CU) found in ascidian mitochondria responsible for decoding non-universal codons AGA/AGG as glycine.

    PubMed

    Kondow, A; Suzuki, T; Yokobori, S; Ueda, T; Watanabe, K

    1999-06-15

    Amino acid assignments of metazoan mitochondrial codons AGA/AGG are known to vary among animal species; arginine in Cnidaria, serine in invertebrates and stop in vertebrates. We recently found that in the mitochondria of the ascidian Halocynthia roretzi these codons are exceptionally used for glycine, and postulated that they are probably decoded by a tRNA(UCU). In order to verify this notion unambig-uously, we determined the complete RNA sequence of the mitochondrial tRNA(UCU) presumed to decode codons AGA/AGG in the ascidian mitochondria, and found it to have an unidentified U derivative at the anticodon first position. We then identified the amino acids attached to the tRNA(U*CU), as well as to the conventional tRNAGly(UCC) with an unmodified U34, in vivo. The results clearly demonstrated that glycine was attached to both tRNAs. Since no other tRNA capable of decoding codons AGA/AGG has been found in the mitochondrial genome, it is most probable that this tRNA(U*CU) does actually translate codons AGA/AGG as glycine in vivo. Sequencing of tRNASer(GCU), which is thought to recognize only codons AGU/AGC, revealed that it has an unmodified guanosine at position 34, as is the case with vertebrate mitochondrial tRNASer(GCU) for codons AGA/AGG. It was thus concluded that in the ascidian, codons AGU/AGC are read as serine by tRNASer(GCU), whereas AGA/AGG are read as glycine by an extra tRNAGly(U*CU). The possible origin of this unorthodox genetic code is discussed. PMID:10352185

  5. Development of transient outward currents coupled with Ca2+-induced Ca2+ release mediates oscillatory membrane potential in ascidian muscle cells.

    PubMed

    Nakajo, Koichi; Okamura, Yasushi

    2004-08-01

    Isolated ascidian Halocynthia roretzi blastomeres of the muscle lineage exhibit muscle cell-like excitability on differentiation despite the arrest of cell cleavage early in development. This characteristic provides a unique opportunity to track changes in ion channel expression during muscle cell differentiation. Here, we show that the intrinsic membrane property of ascidian cleavage-arrested muscle-type cells becomes oscillatory by expressing transient outward currents (I(to)) activated by Ca(2+)-induced Ca(2+) release (CICR) in a maturation-dependent manner. In current-clamp mode, most day 4 (72 h after fertilization) cleavage-arrested muscle cells exhibited an oscillatory membrane potential of -20 mV at 15 Hz, whereas most day 3 (48 h after fertilization) cells exhibited a spiking pattern. In voltage-clamp mode, the day 4 cells exhibited prominent transient outward currents that were not present in day 3 cells. I(to) was abolished by the application of 10 mM caffeine, implying that CICR was involved in I(to) activation. I(to) was based on K(+) efflux and sensitive to tetraethylammonium and some Ca(2+)-activated K(+) channel inhibitors. We found a 60-pS single channel conductance that was activated by local Ca(2+) release in ascidian muscle cell. Voltage-clamp recording with an oscillatory waveform as a command pulse showed that CICR-activated K(+) currents were activated during the falling phase of the membrane potential oscillation. These results suggest that developmental expression of CICR-activated K(+) current plays a role in the maturation of larval locomotion by modifying the intrinsic membrane excitability of muscle cells. PMID:15056691

  6. Ascidian depth zonation on sublittoral hard substrates off deer island, New Brunswick, Canada

    NASA Astrophysics Data System (ADS)

    Hatfield, C.; Logan, A.; Thomas, M. L. H.

    1992-02-01

    The upper surfaces of sublittoral hard substrates in the Deer Island region of the Bay of Fundy, New Brunswick, support diverse, depth-zoned epibenthic communities of which ascidians form a minor part. Their population density was quantitatively studied from photo-transects taken between mean low water (MLW) and 30 m depth at four sites off the Deer Island coast and from 30-140 m depth along two photo-transects in Head Harbour Passage. All photo-analyses were aided by collections from transect survey sites, wharf pilings and salmon cage floats, to yield a total of 15 ascidian species encountered. Ascidians were found at all depths at the four shallow sites. Halocynthia pyriformis and Boltenia ovifera are most common at depths of less than 20 m, while Aplidium pallidum, Didemnum albidum and other species exhibit a marked increase in abundance below this depth. Cluster analysis of ascidians shows an association between B. echinata and B. ovifera, which may reflect resource partitioning, and between A. pallidum-D. albidum and Molgula sp.— A. stellatum, the ecological significance of which are as yet unknown. The community in Head Harbour Passage is animal-dominated and in its deeper sections often shows three-dimensional bottom relief from horse mussel shells. D. albidum, the commonest ascidian, shows a close association with Modiolus modiolus, to which it is normally attached, suggesting that mussel beds may minimize the possibility of dislodgement and even confer a feeding advantage on this ascidian.

  7. Divergent mechanisms regulate conserved cardiopharyngeal development and gene expression in distantly related ascidians

    PubMed Central

    Stolfi, Alberto; Lowe, Elijah K; Racioppi, Claudia; Ristoratore, Filomena; Brown, C Titus; Swalla, Billie J; Christiaen, Lionel

    2014-01-01

    Ascidians present a striking dichotomy between conserved phenotypes and divergent genomes: embryonic cell lineages and gene expression patterns are conserved between distantly related species. Much research has focused on Ciona or Halocynthia spp. but development in other ascidians remains poorly characterized. In this study, we surveyed the multipotent myogenic B7.5 lineage in Molgula spp. Comparisons to the homologous lineage in Ciona revealed identical cell division and fate specification events that result in segregation of larval, cardiac, and pharyngeal muscle progenitors. Moreover, the expression patterns of key regulators are conserved, but cross-species transgenic assays uncovered incompatibility, or ‘unintelligibility’, of orthologous cis-regulatory sequences between Molgula and Ciona. These sequences drive identical expression patterns that are not recapitulated in cross-species assays. We show that this unintelligibility is likely due to changes in both cis- and trans-acting elements, hinting at widespread and frequent turnover of regulatory mechanisms underlying otherwise conserved aspects of ascidian embryogenesis. DOI: http://dx.doi.org/10.7554/eLife.03728.001 PMID:25209999

  8. Induced neural-type differentiation in the cleavage-arrested blastomere isolated from early ascidian embryos.

    PubMed Central

    Okado, H; Takahashi, K

    1990-01-01

    1. Isolated blastomeres and pairs of blastomeres from 8-cell embryos of Halocynthia roretzi and Halocynthia aurantium were cleavage-arrested with cytochalasin B and cultured. Their differentiation was examined in terms of membrane excitability, immunoreactivity to an epidermis-specific monoclonal antibody (2C5), and the presence of acetylcholinesterase. 2. The blastomeres that showed epidermal-type differentiation had Ca2(+)-dependent action potentials and membrane currents, and immunoreactivity to 2C5. The blastomeres that showed neural-type differentiation had Na(+)-, Ca2(+)- and TEA-sensitive delayed K+ channels, and lacked immunoreactivity to 2C5. 3. Cleavage-arrested anterior-animal blastomeres, a4-2, when cultured in isolation from an 8-cell embryo, differentiated exclusively into epidermal-type cells. However, when cultured in contact with anterior-vegetal blastomeres, A4-1, they mostly showed neural-type differentiation (seventeen out of twenty-four cells in H. roretzi). 4. Reduction of the cytochalasin B concentration enhanced neural-type development of a4-2 blastomeres in contact with A4-1 blastomeres in H. aurantium, possibly by tightening the physical contact between the blastomeres. 5. When a cleavage-arrested and isolated a4-2 blastomere was treated with 2% pronase at 10 degrees C for 15 min at the time when sister control embryos reached the 32-cell stage, the blastomere underwent neural-type differentiation in a manner identical to that of a4-2 blastomeres contacted by A4-1 cells. 6. The period during which neural-type differentiation of a4-2 blastomeres could be induced by treatment with pronase was from the 8-cell to the 110-cell stage. At the late gastrula stage neural-type differentiation of a4-2 blastomeres was not induced by pronase. The effective period for neural-type differentiation of a4-2 blastomeres in contact with A4-1 cells was between the 64-cell stage and late gastrula stage. Competence of the a4-2 blastomere to undergo neural

  9. Deep Sequencing of Mixed Total DNA without Barcodes Allows Efficient Assembly of Highly Plastic Ascidian Mitochondrial Genomes

    PubMed Central

    Rubinstein, Nimrod D.; Feldstein, Tamar; Shenkar, Noa; Botero-Castro, Fidel; Griggio, Francesca; Mastrototaro, Francesco; Delsuc, Frédéric; Douzery, Emmanuel J.P.; Gissi, Carmela; Huchon, Dorothée

    2013-01-01

    Ascidians or sea squirts form a diverse group within chordates, which includes a few thousand members of marine sessile filter-feeding animals. Their mitochondrial genomes are characterized by particularly high evolutionary rates and rampant gene rearrangements. This extreme variability complicates standard polymerase chain reaction (PCR) based techniques for molecular characterization studies, and consequently only a few complete Ascidian mitochondrial genome sequences are available. Using the standard PCR and Sanger sequencing approach, we produced the mitochondrial genome of Ascidiella aspersa only after a great effort. In contrast, we produced five additional mitogenomes (Botrylloides aff. leachii, Halocynthia spinosa, Polycarpa mytiligera, Pyura gangelion, and Rhodosoma turcicum) with a novel strategy, consisting in sequencing the pooled total DNA samples of these five species using one Illumina HiSeq 2000 flow cell lane. Each mitogenome was efficiently assembled in a single contig using de novo transcriptome assembly, as de novo genome assembly generally performed poorly for this task. Each of the new six mitogenomes presents a different and novel gene order, showing that no syntenic block has been conserved at the ordinal level (in Stolidobranchia and in Phlebobranchia). Phylogenetic analyses support the paraphyly of both Ascidiacea and Phlebobranchia, with Thaliacea nested inside Phlebobranchia, although the deepest nodes of the Phlebobranchia–Thaliacea clade are not well resolved. The strategy described here thus provides a cost-effective approach to obtain complete mitogenomes characterized by a highly plastic gene order and a fast nucleotide/amino acid substitution rate. PMID:23709623

  10. A functional cellulose synthase from ascidian epidermis

    PubMed Central

    Matthysse, Ann G.; Deschet, Karine; Williams, Melanie; Marry, Mazz; White, Alan R.; Smith, William C.

    2004-01-01

    Among animals, urochordates (e.g., ascidians) are unique in their ability to biosynthesize cellulose. In ascidians cellulose is synthesized in the epidermis and incorporated into a protective coat know as the tunic. A putative cellulose synthase-like gene was first identified in the genome sequences of the ascidian Ciona intestinalis. We describe here a cellulose synthase gene from the ascidian Ciona savignyi that is expressed in the epidermis. The predicted C. savignyi cellulose synthase amino acid sequence showed conserved features found in all cellulose synthases, including plants, but was most similar to cellulose synthases from bacteria, fungi, and Dictyostelium discoidium. However, unlike other known cellulose synthases, the predicted C. savignyi polypeptide has a degenerate cellulase-like region near the carboxyl-terminal end. An expression construct carrying the C. savignyi cDNA was found to restore cellulose biosynthesis to a cellulose synthase (CelA) minus mutant of Agrobacterium tumefaciens, showing that the predicted protein has cellulose synthase activity. The lack of cellulose biosynthesis in all other groups of metazoans and the similarity of the C. savignyi cellulose synthase to enzymes from cellulose-producing organisms support the hypothesis that the urochordates acquired the cellulose biosynthetic pathway by horizontal transfer. PMID:14722352

  11. Species specificity of symbiosis and secondary metabolism in ascidians

    PubMed Central

    Tianero, Ma Diarey B; Kwan, Jason C; Wyche, Thomas P; Presson, Angela P; Koch, Michael; Barrows, Louis R; Bugni, Tim S; Schmidt, Eric W

    2015-01-01

    Ascidians contain abundant, diverse secondary metabolites, which are thought to serve a defensive role and which have been applied to drug discovery. It is known that bacteria in symbiosis with ascidians produce several of these metabolites, but very little is known about factors governing these ‘chemical symbioses'. To examine this phenomenon across a wide geographical and species scale, we performed bacterial and chemical analyses of 32 different ascidians, mostly from the didemnid family from Florida, Southern California and a broad expanse of the tropical Pacific Ocean. Bacterial diversity analysis showed that ascidian microbiomes are highly diverse, and this diversity does not correlate with geographical location or latitude. Within a subset of species, ascidian microbiomes are also stable over time (R=−0.037, P-value=0.499). Ascidian microbiomes and metabolomes contain species-specific and location-specific components. Location-specific bacteria are found in low abundance in the ascidians and mostly represent strains that are widespread. Location-specific metabolites consist largely of lipids, which may reflect differences in water temperature. By contrast, species-specific bacteria are mostly abundant sequenced components of the microbiomes and include secondary metabolite producers as major components. Species-specific chemicals are dominated by secondary metabolites. Together with previous analyses that focused on single ascidian species or symbiont type, these results reveal fundamental properties of secondary metabolic symbiosis. Different ascidian species have established associations with many different bacterial symbionts, including those known to produce toxic chemicals. This implies a strong selection for this property and the independent origin of secondary metabolite-based associations in different ascidian species. The analysis here streamlines the connection of secondary metabolite to producing bacterium, enabling further biological and

  12. Genome Sequence of the Sponge-Associated Ruegeria halocynthiae Strain MOLA R1/13b, a Marine Roseobacter with Two Quorum-Sensing-Based Communication Systems

    PubMed Central

    Doberva, Margot; Sanchez-Ferandin, Sophie; Ferandin, Yoan; Intertaglia, Laurent; Croué, Julie; Suzuki, Marcelino; Lebaron, Philippe

    2014-01-01

    Ruegeria halocynthiae MOLA R1/13b is an alphaproteobacterium isolated from the Mediterranean sea sponge Crambe crambe. We report here the genome sequence and its annotation, revealing the presence of quorum-sensing genes. This is the first report of the full genome of a Ruegeria halocynthiae strain. PMID:25301648

  13. Genome Sequence of the Sponge-Associated Ruegeria halocynthiae Strain MOLA R1/13b, a Marine Roseobacter with Two Quorum-Sensing-Based Communication Systems.

    PubMed

    Doberva, Margot; Sanchez-Ferandin, Sophie; Ferandin, Yoan; Intertaglia, Laurent; Croué, Julie; Suzuki, Marcelino; Lebaron, Philippe; Lami, Raphaël

    2014-01-01

    Ruegeria halocynthiae MOLA R1/13b is an alphaproteobacterium isolated from the Mediterranean sea sponge Crambe crambe. We report here the genome sequence and its annotation, revealing the presence of quorum-sensing genes. This is the first report of the full genome of a Ruegeria halocynthiae strain. PMID:25301648

  14. The molecular basis of allorecognition in ascidians.

    PubMed

    Ben-Shlomo, Rachel

    2008-11-01

    The process of allorecognition consists of an ability to discriminate self from non-self. This discrimination is used either to identify non-self cells and reject them ("non-self histocompatibility") or to identify self cells and reject them (as in the avoidance of self-fertilization by hermaphrodites ("self incompatibility"). The molecular basis governing these two distinct systems has been studied recently in hermaphroditic ascidian urochordates. Harada et al. postulated two highly polymorphic self-incompatibility loci, Themis (A and B), that are transcribed from both strands, forward to yield sperm (s-) trans-membrane antigen, and reverse to yield the egg vitelline coat (v-) receptor. De Tomaso et al. characterized a candidate histocompatibility locus, encoding a highly variable immunoglobulin. Nyholm et al. isolated its candidate allorecognition receptor, fester. Only a minute similarity was found in the structure of the genes involved. It appears that ascidian harbor two very separate types of labeling and recognition genetic systems: one for self and the other for non-self. PMID:18937348

  15. Changes in gelsolin expression during ascidian metamorphosis.

    PubMed

    Ohtsuka, Y; Okamura, Y; Obinata, T

    2001-05-01

    Gelsolin is an actin regulatory protein that is expressed in a wide variety of tissues and is especially abundant in muscle and blood cells. The role of gelsolin during structural reorganization of the body, such as during metamorphosis or regeneration, is poorly understood. We analyzed changes in gelsolin expression during ascidian embryogenesis and metamorphosis using nucleic acid probes and a monoclonal antibody (AS23) specific for ascidian gelsolin; our results indicated that gelsolin is maternally provided and that its de novo gene transcription is initiated during the neurula stage. In the larva, gelsolin was detectable in specific types of nerve cells, i.e. the adhesive papillae, motor neurons and epidermal sensory neurons. During metamorphosis, the expression of gelsolin changes markedly: the expression is suppressed in nerve tissues after tail resorption but is induced in mesodermal tissues. Gelsolin accumulated in mesenchyme cells until the onset of tail resorption, and following tail resorption, these cells migrated to the tunic and differentiated into tunic cells with many fine processes. Migration of the mesenchyme cells into the tunic was completely inhibited by treatment with cytochalasin B. Gelsolin was colocalized with actin in tunic cells, suggesting that it is involved in the rearrangement of actin filaments during cell locomotion or morphogenesis. PMID:11455440

  16. The central nervous system of ascidian larvae.

    PubMed

    Hudson, Clare

    2016-09-01

    Ascidians are marine invertebrate chordates. Their tadpole larvae contain a dorsal tubular nervous system, resulting from the rolling up of a neural plate. Along the anterior-posterior (A-P) axis, the central nervous system (CNS) is organized into a sensory vesicle, neck, trunk ganglion, and tail nerve cord and consists of approximately only 330 cells, of which around 100 are thought to be neurons. The organization of distinct neuronal cell types and neurotransmitter gene expression within the CNS has been described. The unique developmental mode of ascidians, with a small number of cells and a fixed cell division pattern, allows individual cells to be traced throughout development. This feature has led to the complete documentation of the cell lineages of certain cell types in the CNS. Thus, a step-by-step understanding of nervous system development from the initial stages of neural induction to the neurogenesis of individual neurons is a feasible goal. The genetic control of neural fate induction and early neural plate patterning are now well understood. The molecular mechanisms specifying the cholinergic neurons of the trunk ganglion as well as the pigment cells of the sensory organs are also well elucidated. In addition, studies have begun on the morphogenetic processes of neurulation. Remaining challenges include building an embryonic atlas integrating gene expression patterns, cell lineage, and neuronal cell types as well as developing the gene regulatory networks of cell fate specification and integrating them with the genetic control of morphogenesis. WIREs Dev Biol 2016, 5:538-561. doi: 10.1002/wdev.239 For further resources related to this article, please visit the WIREs website. PMID:27328318

  17. Diversity of Actinobacteria Associated with the Marine Ascidian Eudistoma toealensis.

    PubMed

    Steinert, Georg; Taylor, Michael W; Schupp, Peter J

    2015-08-01

    Ascidians have yielded a wide variety of bioactive natural products. The colonial ascidian Eudistoma toealensis from Micronesia has been identified as the source of a series of staurosporine derivatives, though the exact origin of these derivatives is still unknown. To identify known staurosporine-producing microbes associated with E. toealensis, we analyzed with 16S rRNA gene tag pyrosequencing the overall bacterial community and focused on potential symbiotic bacteria already known from other ascidians or other marine hosts, such as sponges. The described microbiota was one of very high diversity, comprising 43 phyla: two from archaea, 34 described bacterial phyla, and seven candidate bacterial phyla. Many bacteria, which are renowned community members of other ascidians and marine holobionts, such as sponges and corals, were also part of the E. toealensis microbial community. Furthermore, two known producers of indolocarbazoles, Salinispora and Verrucosispora, were found with high abundance exclusively in the ascidian tissue, suggesting that microbial symbionts and not the organism itself may be the true producers of the staurosporines in E. toealensis. PMID:25678260

  18. Centrosomes and spindles in ascidian embryos and eggs.

    PubMed

    McDougall, Alex; Chenevert, Janet; Pruliere, Gerard; Costache, Vlad; Hebras, Celine; Salez, Gregory; Dumollard, Remi

    2015-01-01

    During embryonic development and maternal meiotic maturation, positioning of the mitotic/meiotic spindle is subject to control mechanisms that meet the needs of the particular cell type. Here we review the methods, molecular tools, and the ascidian model we use to study three different ways in which centrosomes or spindles are positioned in three different cellular contexts. First, we review unequal cleavage in the ascidian germ lineage. In the germ cell precursors, a large macromolecular structure termed the centrosome-attracting body causes three successive rounds of unequal cleavage from the 8- to the 64-cell stage. Next, we discuss spindle positioning underlying the invariant cleavage pattern. Ascidian embryos display an invariant cleavage pattern whereby the mitotic spindle aligns in a predetermined orientation in every blastomere up to the gastrula stage (composed of 112 cells). Finally, we review methods and approaches to study meiotic spindle positioning in eggs. PMID:26175446

  19. Genomics and developmental approaches to an ascidian adenohypophysis primordium.

    PubMed

    Kano, Shungo

    2010-07-01

    Ascidians, which are the closest phylogenetic relatives to vertebrates, lack a distinct pituitary gland, which is the major endocrine gland in vertebrates. Nevertheless, for the past 130 years, it has been debated that the ascidian neural complex (NC) is homologous to the pituitary. Of the three major components of the NC, the neural gland (NG) has mainly been thought to be the ascidian counterpart of the pituitary. Recently, however, the ciliated funnel, and not the NG, was postulated to be the adenohypophysis (AH) primordium because it is likely derived from oral ectoderm, and because the expression of several placodal genes is comparable to their expression in vertebrates. An extensive in silico survey of the Ciona intestinalis genome sequence revealed that genes encoding pituitary hormones are absent in ascidians. Under the circumstances, this thesis attempts to find a path that shows that the AH primordium is recognizable in the ascidian by revisiting molecular and developmental data from recent public resources on C. intestinalis, and through the use of advanced bio-imaging techniques. A putative Ciona genetic pathway, which was constructed by referring to data from mammals, shows that only a patchwork of the genetic network exists to achieve terminal differentiation of the AH endocrine cells in the Ciona genome. Re-annotation on glycoprotein hormone related proteins, a GPA2/ARP and two GPB5/BRP ones previously reported, reveals that the GPA2 locus contains two splicing variants, and one variant likely formed a three-dimensional conformation similar to that of human GPA2. No clone of the GPB5/BRP1 locus has been isolated, and another candidate, BRP2, is unlikely to be a GPB5. Next, I argued a possibility that endocrine activities of Ciona species could be specialized in association with its short generation time, and I suggest that not only Ciona species but also other ascidians should be studied in order to understand ascidian endocrinology. Confocal images

  20. The secret to a successful relationship: lasting chemistry between ascidians and their symbiotic bacteria

    PubMed Central

    Schmidt, Eric W.

    2014-01-01

    Bioactive secondary metabolites are common components of marine animals. In many cases, symbiotic bacteria, and not the animals themselves, synthesize the compounds. Among marine animals, ascidians are good models for understanding these symbioses. Ascidians often contain potently bioactive secondary metabolites as their major extractable components. Strong evidence shows that ~8% of the known secondary metabolites from ascidians are made by symbiotic bacteria, and indirect evidence implicates bacteria in the synthesis of many more. Far from being “secondary” to the animals, secondary metabolites are essential components of the interaction between host animals and their symbiotic bacteria. These interactions have complex underlying biology, but the chemistry is clearly ascidian-species specific. The chemical interactions are ancient in at least some cases, and they are widespread among ascidians. Ascidians maintain secondary metabolic symbioses with bacteria that are phylogenetically diverse, indicating a convergent solution to obtaining secondary metabolites and reinforcing the importance of secondary metabolism in animal survival. PMID:25937788

  1. The influence of substrate material on ascidian larval settlement.

    PubMed

    Chase, Anna L; Dijkstra, Jennifer A; Harris, Larry G

    2016-05-15

    Submerged man-made structures present novel habitat for marine organisms and often host communities that differ from those on natural substrates. Although many factors are known to contribute to these differences, few studies have directly examined the influence of substrate material on organism settlement. We quantified larval substrate preferences of two species of ascidians, Ciona intestinalis (cryptogenic, formerly C. intestinalis type B) and Botrylloides violaceus (non-native), on commonly occurring natural (granite) and man-made (concrete, high-density polyethylene, PVC) marine materials in laboratory trials. Larvae exhibited species-specific settlement preferences, but generally settled more often than expected by chance on concrete and HDPE. Variation in settlement between materials may reflect preferences for rougher substrates, or may result from the influence of leached chemicals on ascidian settlement. These findings indicate that an experimental plate material can influence larval behavior and may help us understand how substrate features may contribute to differences in settlement in the field. PMID:27039957

  2. Chemical defense against fouling in the solitary ascidian Phallusia nigra.

    PubMed

    Mayzel, Boaz; Haber, Markus; Ilan, Micha

    2014-12-01

    The solitary ascidian Phallusia nigra is rarely fouled by epibionts. Here, we tested the antifouling activity of its crude extracts in laboratory and field assays. P. nigra extracts inhibited the growth of all eight tested environmental bacteria and two of four laboratory bacteria. Extracts of the sympatric, but fouled solitary ascidian Herdmania momus inhibited only one test bacterium. Scanning electron microscopy confirmed that the tunic surface of P. nigra is largely bacteria-free. Both ascidian extracts significantly inhibited the larval metamorphosis of the bryozoan Bugula neritina at the tested concentration range of 0.05-2 mg ml(-1). Both crude extracts were toxic to larvae of the brine shrimp Artemia salina at natural volumetric whole-tissue concentrations, but only P. nigra showed activity at 2 mg ml(-1) and below (LC50 = 1.11 mg ml(-1)). P. nigra crude extracts also significantly reduced the settlement of barnacles, polychaetes, and algae in Mediterranean field assays and barnacle settlement in Red Sea trials. Comparisons between control experiments and pH values monitored in all experiments indicate that the observed effects were not due to acidity of the organic extracts. Our results show that P. nigra secondary metabolites have antifouling activities, which may act in synergy with previously proposed physiological antifouling mechanisms. PMID:25572211

  3. Temporal stability of bacterial symbionts in a temperate ascidian

    PubMed Central

    López-Legentil, Susanna; Turon, Xavier; Espluga, Roger; Erwin, Patrick M.

    2015-01-01

    In temperate seas, both bacterioplankton communities and invertebrate lifecycles follow a seasonal pattern. To investigate whether the bacterial community associated with the Mediterranean ascidian Didemnum fulgens exhibited similar variations, we monitored its bacterial community structure monthly for over a year using terminal restriction fragment length polymorphism and clone library analyses based on a nearly full length fragment of the 16S rRNA gene. D. fulgens harbored a bacterial consortium typical of ascidians, including numerous members of the phylum Proteobacteria, and a few members of the phyla Cyanobacteria and Acidobacteria. The overall bacterial community in D. fulgens had a distinct signature from the surrounding seawater and was stable over time and across seasonal fluctuations in temperature. Bacterial symbionts were also observed around animal cells in the tunic of adult individuals and in the inner tunic of D. fulgens larvae by transmission electron microscopy. Our results suggest that, as seen for sponges and corals, some species of ascidians host stable and unique bacterial communities that are at least partially inherited by their progeny by vertical transmission. PMID:26441944

  4. New distributional data on ascidian fauna (Tunicata: Ascidiacea) from Mandapam coast, Gulf of Mannar, India

    PubMed Central

    Akram, Soban A; Arshan, Kaleem ML

    2016-01-01

    Abstract Background Ascidians play a key role in the ecology and biodiversity of marine ecosystem. Ascidians can be transported in ship ballast water and while attached to ship and boat hulls. Heavy traffic by domestic and international ships as well as cargo vessels between the major and minor ports warrants continuous monitoring for new introductions of ascidians. The Mandapam coast is situated in the Gulf of Mannar, India, a marine hot spot area in the Indian Ocean which provides an environment suitable for the settlement of ascidians. New information A total of 30 species of ascidians were reported from Mandapam coastal waters, of which 26 species were new to the study area and five species: Ecteinascidia turbinata, Eudistoma carnosum, Trididemnum caelatum, T. vermiforme and Didemnum spadix, were new to India. PMID:27099557

  5. Prochloron-ascidian symbioses: Photosynthetic potential and productivity

    NASA Technical Reports Server (NTRS)

    Lewin, R. A.; Cheng, L.; Alberte, R. S.

    1983-01-01

    The chlorophyll content of didemnid asidians with symbiotic algae (Prochloron) from oligotropic tropical marine waters around Palau, Western Carolin Islands is discussed. Several species contain as much chlorophyll per unit dry weight as many herbaceous crop plants and more than do other symbiotic associations such as lichens, green Hydra, etc. Their chlorphyllA/B ratios (3-9) were generally much lighter than those of angiosperms (2-4). Where they abound, Prochloron - ascidian symbiosis could make a major contribution to the productivity, especially in localized areas of tropical marine waters characterized by low nutrient levels and high irradiance.

  6. Photosymbiotic ascidians from Pari Island (Thousand Islands, Indonesia).

    PubMed

    Hirose, Euichi; Iskandar, Budhi Hascaryo; Wardiatno, Yusli

    2014-01-01

    Photosymbiotic ascidian fauna were surveyed in the subtidal zone off Pari Island in the Thousand Islands (Java Sea, Indonesia). Nine species were recorded: Didemnum molle, Trididemnum miniatum, Lissoclinum patella, L. punctatum, L. timorense, Diplosoma gumavirens, D. simile, D. simileguwa, and D. virens. All of these species have been previously recorded in the Ryukyu Archipelago, Japan. Diplosoma gumavirens and D. simileguwa were originally described from the Ryukyu Archipelago in 2009 and 2005, respectively, and all of the observed species are potentially widely distributed in Indo-West Pacific coral reefs. PMID:25061385

  7. Amino Acid-Derived Metabolites from the Ascidian Aplidium sp.

    PubMed

    Won, Tae Hyung; Kim, Chang-Kwon; Lee, So-Hyoung; Rho, Boon Jo; Lee, Sang Kook; Oh, Dong-Chan; Oh, Ki-Bong; Shin, Jongheon

    2015-06-01

    Four new iodobenzene-containing dipeptides (1-4), a related bromotryptophan-containing dipeptide (5), and an iodophenethylamine (6) were isolated from the ascidian Aplidium sp. collected off the coast of Chuja-do, Korea. The structures of these novel compounds, designated as apliamides A-E (1-5) and apliamine A (6) were determined via combined spectroscopic analyses. The absolute configuration of the amino acid residue in 1 was determined by advanced Marfey's analysis. Several of these compounds exhibited moderate cytotoxicity and significant inhibition against Na+/K+-ATPase (4). PMID:26087023

  8. Ascidiaceihabitans donghaensis gen. nov., sp. nov., isolated from the golden sea squirt Halocynthia aurantium.

    PubMed

    Kim, Young-Ok; Park, Sooyeon; Nam, Bo-Hye; Lee, Chu; Park, Ja-Min; Kim, Dong-Gyun; Yoon, Jung-Hoon

    2014-12-01

    A Gram-stain-negative, aerobic, non-motile and coccoid, ovoid or rod-shaped bacterial strain, designated RSS1-M3(T), was isolated from a golden sea squirt (Halocynthia aurantium) collected from the East Sea, South Korea. Strain RSS1-M3(T) grew optimally at 30 °C, at pH 7.0-8.0 and in presence of 2.0 % (w/v) NaCl. Strain RSS1-M3(T) exhibited the highest 16S rRNA gene sequence similarity (96.55 %) to the type strain of Pelagicola litoralis. Neighbour-joining and maximum-likelihood phylogenetic trees based on 16S rRNA gene sequences revealed that strain RSS1-M3(T) clustered with the type strains, or proposed type strains, of Planktotalea frisia, Pacificibacter maritimus, Roseovarius marinus and Halocynthiibacter namhaensis, showing sequence similarity of 94.88-96.32 %. Strain RSS1-M3(T) contained Q-10 as the predominant ubiquinone and C18 : 1ω7c and C16 : 0 as the major fatty acids. The polar lipid profile of strain RSS1-M3(T), containing phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, one unidentified aminolipid and one unidentified lipid as major components, could be distinguished from those of the phylogenetically related genera. The DNA G+C content of strain RSS1-M3(T) was 55.8 mol%. On the basis of the phylogenetic, chemotaxonomic and phenotypic properties, strain RSS1-M3(T) is considered to represent a novel species of a new genus within the class Alphaproteobacteria, for which the name Ascidiaceihabitans donghaensis gen. nov., sp. nov. is proposed. The type strain is RSS1-M3(T) ( = KCTC 42118(T) = CECT 8599(T)). PMID:25205799

  9. Bioadhesion in ascidians: a developmental and functional genomics perspective

    PubMed Central

    Pennati, Roberta; Rothbächer, Ute

    2015-01-01

    The development of bioadhesives inspired from marine animals is a promising approach to generate new tissue-compatible medical components. A number of marine species, through their adhesive properties, also represent significant foulers that become increasingly problematic to aquaculture, shipping or local biodiversity. In order to develop more sophisticated man-made glues and/or efficient fouling resistant surfaces, it is important to understand the mechanical, structural and molecular properties of adhesive organs in selected species. Ascidians are marine invertebrates with larvae that opportunistically attach to almost any type of submerged surface to undergo metamorphosis into permanently sessile adults. Not only do they represent a globally important fouling organism, but they are becoming increasingly popular as model organisms for developmental biology. The latter is due to their phylogenetic position as the sister group to the vertebrates and their cellular and molecular accessibility for experimentation. In this paper, we review the mechanisms of larval adhesion in ascidians and draw conclusions from comparative analyses of selected species. We further discuss how knowledge from a developmental and functional genomics point of view can advance our understanding of cellular and molecular signatures and their hierarchical usage in animal adhesive organs. PMID:25657840

  10. Photosymbiotic ascidians in Singapore: turbid waters may reduce living space

    PubMed Central

    Su, Shih-Wei; Hirose, Euichi; Chen, Serina Lee Siew; Mok, Michael Hin-Kiu

    2013-01-01

    Abstract The photosymbiotic ascidian fauna at Changi Beach, Pulau Semakau, Sentosa and St. John’s Island, Singapore were surveyed. A total of five species, Diplosoma simile, Lissoclinum bistratum, Lissoclinum punctatum, Lissoclinum timorense and Trididemnum cyclops, were recorded, with Lissoclinum timorense and Trididemnum cyclops being newly recorded in Singapore. However, no photosymbiotic species were found at Changi Beach probably due to the polluted waters in the region. Coastal development has caused Singapore waters to become turbid, leading to decrease in suitable habitats for photosymbiotic ascidians. Clean waters in Pulau Semakau probably provide a better environment for the growth of photosymbiotic ascidians and this area has a greater variety of these ascidians than the other areas in Singapore. Each of the five species has also been recorded in the Ryukyu Archipelago (Japan) and three species (Diplosoma simile, Lissoclinum bistratum and Trididemnum cyclops) have also been recorded in Taiwan. PMID:23794913

  11. The Comparative Organismal Approach in Evolutionary Developmental Biology: Insights from Ascidians and Cavefish.

    PubMed

    Jeffery, William R

    2016-01-01

    Important contributions to evolutionary developmental biology have been made using the comparative organismal approach. As examples, I describe insights obtained from studies of Molgula ascidians and Astyanax cavefish. PMID:26970636

  12. Tenacibaculum ascidiaceicola sp. nov., isolated from the golden sea squirt Halocynthia aurantium.

    PubMed

    Kim, Young-Ok; Park, In-Suk; Park, Sooyeon; Nam, Bo-Hye; Park, Ji-Min; Kim, Dong-Gyun; Yoon, Jung-Hoon

    2016-03-01

    A Gram-stain-negative, non-flagellated, non-spore-forming bacterial strain motile by gliding, designated RSS1-6T, was isolated from a golden sea squirt Halocynthia aurantium and its taxonomic position was investigated by using a polyphasic approach. Strain RSS1-6T grew optimally at 30-37 °C and in the presence of 1.0-4.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain RSS1-6T fell within the clade comprising species of the genus Tenacibaculum, clustering with the type strains of Tenacibaculum discolor, Tenacibaculum litoreum and Tenacibaculum gallaicum with which it exhibited 16S rRNA gene sequence similarity values of 98.5-99.5 %. Strain RSS1-6T contained MK-6 as the predominant menaquinone and iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) as the major fatty acids. The major polar lipids of strain RSS1-6T were phosphatidylethanolamine, two unidentified lipids, one unidentified aminophospholipid and one unidentified glycolipid. The DNA G+C content was 32.5 mol% and the mean DNA-DNA relatedness values with the type strains of T. discolor, T. litoreum and T. gallaicum were 17.3-25.2 %. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain RSS1-6T is separated from other recognized species of the genus Tenacibaculum. On the basis of the data presented, strain RSS1-6T is considered to represent a novel species of the genus Tenacibaculum, for which the name Tenacibaculum ascidiaceicola sp. nov. is proposed. The type strain is RSS1-6T ( = KCTC 42702T = NBRC 111225T). PMID:26674528

  13. Litoreibacter ascidiaceicola sp. nov., isolated from the golden sea squirt Halocynthia aurantium.

    PubMed

    Kim, Young-Ok; Park, Sooyeon; Nam, Bo-Hye; Park, Ji-Min; Kim, Dong-Gyun; Yoon, Jung-Hoon

    2014-08-01

    A Gram-stain-negative, aerobic, non-motile and coccoid, ovoid or rod-shaped bacterial strain, designated RSS4-C1(T), was isolated from a golden sea squirt (Halocynthia aurantium) collected from the East Sea, South Korea. The novel strain grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 1.0-3.0% (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences revealed that strain RSS4-C1(T) fell within the clade comprising the type strains of species of the genus Litoreibacter . Strain RSS4-C1(T) exhibited the highest 16S rRNA gene sequence similarity (99.6%) to the type strain of Litoreibacter albidus and sequence similarities of 96.5-98.5% to type strains of other recognized species of the genus Litoreibacter. Strain RSS4-C1(T) contained Q-10 as the predominant ubiquinone and C(18 : 1)ω7c and 11-methyl-C(18 : 1)ω7c as the major fatty acids. The major polar lipids of strain RSS4-C1(T) were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified lipid and one unidentified aminolipid. The DNA G+C content of strain RSS4-C1(T) was 58.0 mol% and its DNA-DNA relatedness values with type strains of four species of the genus Litoreibacter were 21-34%. The differential phenotypic properties, together with phylogenetic and genetic distinctiveness, revealed that strain RSS4-C1(T) is distinct from other species of the genus Litoreibacter. On the basis of the data presented, strain RSS4-C1(T) is considered to represent a novel species of the genus Litoreibacter, for which the name Litoreibacter ascidiaceicola sp. nov. is proposed. The type strain is RSS4-C1(T) ( = KCTC 42050(T) = CECT 8539(T)). PMID:24812362

  14. Localization of symbiotic cyanobacteria in the colonial ascidian Trididemnum miniatum (Didemnidae, Ascidiacea).

    PubMed

    Hirose, Euichi; Hirose, Mamiko; Neilan, Brett A

    2006-05-01

    Trididemnum miniatum is a colonial ascidian harboring the photosymbiotic prokaryote Prochloron sp. These bacterial cells are located in the tunic of the host animal. The present study revealed, by ultrastructural analysis, that the Prochloron cells were exclusively distributed and proliferated in the tunic. They were shown to be embedded in the tunic matrix and to have no direct contact with ascidian cells. Some tunic cells of the ascidians, however, did phagocytize and digest the symbiont. Round cell masses were sometimes found in the tunic and appeared to consist of disintegrating cyanobacterial cells. The thoracic epidermis of ascidian zooids was often digitated, and the epidermal cells extended microvilli into the tunic. Since there were no Prochloron cells in the alimentary tract of the ascidian zooids, the photosymbionts would not be considered part of the typical diet of the host ascidians. Thin layer chromatography showed that the symbionts possessed both chlorophyll a and b, while a 16S rRNA gene phylogeny supported the identification of the photosymbiont of T. miniatum as Prochloron sp. PMID:16766862

  15. Toll-like Receptors of the Ascidian Ciona intestinalis

    PubMed Central

    Sasaki, Naoko; Ogasawara, Michio; Sekiguchi, Toshio; Kusumoto, Shoichi; Satake, Honoo

    2009-01-01

    Key transmembrane proteins in the innate immune system, Toll-like receptors (TLRs), have been suggested to occur in the genome of non-mammalian organisms including invertebrates. However, authentic invertebrate TLRs have been neither structurally nor functionally investigated. In this paper, we originally present the structures, localization, ligand recognition, activities, and inflammatory cytokine production of all TLRs of the ascidian Ciona intestinalis, designated as Ci-TLR1 and Ci-TLR2. The amino acid sequence of Ci-TLR1 and Ci-TLR2 were found to possess unique structural organization with moderate sequence similarity to functionally characterized vertebrate TLRs. ci-tlr1 and ci-tlr2 genes were expressed predominantly in the stomach and intestine as well as in hemocytes. Ci-TLR1 and Ci-TLR2 expressed in HEK293 cells, unlike vertebrate TLRs, were localized to both the plasma membrane and endosomes. Intriguingly, both Ci-TLR1 and Ci-TLR2 stimulate NF-κB induction in response to multiple pathogenic ligands such as double-stranded RNA, and bacterial cell wall components that are differentially recognized by respective vertebrate TLRs, revealing that Ci-TLRs recognize broader pathogen-associated molecular patterns than vertebrate TLRs. The Ci-TLR-stimulating pathogenic ligands also induced the expression of Ci-TNFα in the intestine and stomach where Ci-TLRs are expressed. These results provide evidence that the TLR-triggered innate immune systems are essentially conserved in ascidians, and that Ci-TLRs possess “hybrid” biological and immunological functions, compared with vertebrate TLRs. Moreover, it is presumed that chordate TLR ancestors also acquired the Ci-TLR-like multiple cellular localization and pathogen-associated molecular pattern recognition. PMID:19651780

  16. Sunlight Damage To The Solitary Ascidian Chelyosoma productum

    NASA Astrophysics Data System (ADS)

    Flores, E.

    2004-12-01

    Chelyosoma productum (Stimpson) is a temperate solitary ascidian commonly found in Puget Sound and the San Juan Archipelago, Washington, USA. Adult populations are restricted to deeper subtidal regions or shaded shallow-water habitats, such as docks in shaded marinas. C. productum adults have a thin translucent outer tunic that may provide very little if any protection from solar damage. I hypothesized that sunlight may be setting limits on the distribution of this species. Since adult ascidians are sessile and rely on earlier life stages for their distribution, all life stages of Chelyosoma productum were tested. In this study, I examined the effects of sunlight exposure in embryos, larvae, juveniles and adults of Chelyosoma productum. I isolated the PAR, UVA and UVB portions of the spectrum and exposed all life stages using natural sunlight. I also sampled shallow-water dock habitats to see how adult distributions were related to light exposure. The embryonic development in C. productum was negatively affected by any solar exposure. Most embryos exposed to UV light failed to develop normally and those that did could not subsequently settle. This species produces embryos of different colors; two (purple and brown) were observed in my experiments. Damage from light exposure differed between the color morphs. Overall, the brown morph was more tolerant of light exposure than was the purple morph across all life stages. The only exception to this general pattern was that purple embryos were remarkably resistant to light damage. The distribution of C. productum is restricted to areas with no direct solar exposure. However, even within shaded environments where they were abundant, subpopulations related to the color dimorphism were observed. The significance of the brown and purple pigments in embryos and larvae remains largely unknown. However, adults with brown eggs were found to be more prevalent in edge environments where there was higher light exposure. Purple

  17. Description of Lutimonas halocynthiae sp. nov., isolated from a golden sea squirt (Halocynthia aurantium), reclassification of Aestuariicola saemankumensis as Lutimonas saemankumensis comb. nov. and emended description of the genus Lutimonas.

    PubMed

    Kim, Young-Ok; Park, Sooyeon; Nam, Bo-Hye; Jung, Yong-Taek; Kim, Dong-Gyun; Bae, Kyung Sook; Yoon, Jung-Hoon

    2014-06-01

    A Gram-stain-negative, non-motile, coccoid, ovoid or rod-shaped bacterial strain, designated RSS3-C1(T), was isolated from a golden sea squirt (Halocynthia aurantium) collected from the East Sea, South Korea. Strain RSS3-C1(T) was found to grow optimally at 20-25 °C, at pH 7.0-8.0 and in the presence of 2.0% (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences revealed that strain RSS3-C1(T) clustered with the type strains of Lutimonas vermicola and Aestuariicola saemankumensis. Strain RSS3-C1(T) exhibited 98.8% 16S rRNA gene sequence similarity to each type strain. Strain RSS3-C1(T) contained MK-6 as the predominant menaquinone and iso-C(15 : 0), iso-C(17 : 0) 3-OH and anteiso-C(15 : 0) as the major fatty acids. The major polar lipids of strain RSS3-C1(T) were phosphatidylethanolamine and two unidentified lipids. The DNA G+C content of strain RSS3-C1(T) was 39.2 mol%, and DNA-DNA relatedness to the type strains of and was 21±5.3 and 26±7.5 %, respectively. The differential phenotypic properties, together with its phylogenetic and genetic distinctiveness, revealed that strain RSS3-C1(T) is separated from and . On the basis of the data presented, strain RSS3-C1(T) is considered to represent a novel species of the genus Lutimonas, for which the name Lutimonas halocynthiae sp. nov. is proposed. The type strain is RSS3-C1(T) ( = KCTC 32537(T) = CECT 8444(T)). In this study, it is also proposed that Aestuariicola saemankumensis should be reclassified as a member of the genus Lutimonas, as Lutimonas saemankumensis comb. nov. (type strain SMK-142(T) = KCTC 22171(T) = CCUG 55329(T)), and the description of the genus Lutimonas is emended. PMID:24614845

  18. Genetic pathways for differentiation of the peripheral nervous system in ascidians.

    PubMed

    Waki, Kana; Imai, Kaoru S; Satou, Yutaka

    2015-01-01

    Ascidians belong to tunicates, the sister group of vertebrates. Peripheral nervous systems (PNSs) including epidermal sensory neurons (ESNs) in the trunk and dorsal tail regions of ascidian larvae are derived from cells adjacent to the neural plate, as in vertebrates. On the other hand, peripheral ESNs in the ventral tail region are derived from the ventral ectoderm under the control of BMP signalling, reminiscent of sensory neurons of amphioxus and protostomes. In this study, we show that two distinct mechanisms activate a common gene circuit consisting of Msx, Ascl.b, Tox, Delta.b and Pou4 in the dorsal and ventral regions to differentiate ESNs. Our results suggest that ventral ESNs of the ascidian larva are not directly homologous to vertebrate PNSs. The dorsal ESNs might have arisen via co-option of the original PNS gene circuit to the neural plate border in an ancestral chordate. PMID:26515371

  19. The Mediterranean non-indigenous ascidian Polyandrocarpa zorritensis: Microbiological accumulation capability and environmental implications.

    PubMed

    Stabili, Loredana; Licciano, Margherita; Longo, Caterina; Lezzi, Marco; Giangrande, Adriana

    2015-12-15

    We investigated the bacterial accumulation and digestion capability of Polyandrocarpa zorritensis, a non-indigenous colonial ascidian originally described in Peru and later found in the Mediterranean. Microbiological analyses were carried out on homogenates from "unstarved" and "starved" ascidians and seawater from the same sampling site (Adriatic Sea, Italy). Culturable heterotrophic bacteria (22 °C), total culturable bacteria (37 °C) and vibrios abundances were determined on Marine Agar 2216, Plate Count Agar and TCBS Agar, respectively. Microbial pollution indicators were measured by the most probable number method. All the examined microbiological groups were accumulated by ascidians but differently digested. An interesting outcome is the capability of P. zorritensis to digest allochthonous microorganisms such as coliforms as well as culturable bacteria at 37 °C, counteracting the effects of microbial pollution. Thus, the potential exploitation of these filter feeders to restore polluted seawater should be taken into consideration in the management of this alien species. PMID:26561443

  20. Time course for tail regression during metamorphosis of the ascidian Ciona intestinalis.

    PubMed

    Matsunobu, Shohei; Sasakura, Yasunori

    2015-09-01

    In most ascidians, the tadpole-like swimming larvae dramatically change their body-plans during metamorphosis and develop into sessile adults. The mechanisms of ascidian metamorphosis have been researched and debated for many years. Until now information on the detailed time course of the initiation and completion of each metamorphic event has not been described. One dramatic and important event in ascidian metamorphosis is tail regression, in which ascidian larvae lose their tails to adjust themselves to sessile life. In the present study, we measured the time associated with tail regression in the ascidian Ciona intestinalis. Larvae are thought to acquire competency for each metamorphic event in certain developmental periods. We show that the timing with which the competence for tail regression is acquired is determined by the time since hatching, and this timing is not affected by the timing of post-hatching events such as adhesion. Because larvae need to adhere to substrates with their papillae to induce tail regression, we measured the duration for which larvae need to remain adhered in order to initiate tail regression and the time needed for the tail to regress. Larvae acquire the ability to adhere to substrates before they acquire tail regression competence. We found that when larvae adhered before they acquired tail regression competence, they were able to remember the experience of adhesion until they acquired the ability to undergo tail regression. The time course of the events associated with tail regression provides a valuable reference, upon which the cellular and molecular mechanisms of ascidian metamorphosis can be elucidated. PMID:26102482

  1. Proteomics of ionomycin-induced ascidian sperm reaction: Released and exposed sperm proteins in the ascidian Ciona intestinalis.

    PubMed

    Nakazawa, Shiori; Shirae-Kurabayashi, Maki; Otsuka, Kei; Sawada, Hitoshi

    2015-12-01

    Sperm proteins mediating sperm-egg interaction should be exhibited on the sperm surface, or exposed or released when sperm approach an egg. In ascidians (protochordates), sperm undergo a sperm reaction, characterized by enhanced sperm motility and mitochondrial swelling and shedding on contact with the vitelline coat (VC) or by treatment with Ca(2+) ionophore. Here, proteomic analysis was conducted on sperm exudates and sperm surface proteins using ionomycin-induced sperm reaction and cell-impermeable labeling in Ciona intestinalis type A (C. robusta). In the exudate from sperm treated with ionomycin, membrane proteins including a possible VC receptor CiUrabin were abundant, indicating the release of membranous compartments during sperm reaction. Among the surface proteins XP_009859314.1 (uncharacterized protein exhibiting homology to HrTTSP-1) was most abundant before the sperm reaction, but XP_004227079.1 (unknown Ig superfamily protein) appears to be most abundantly exposed by the sperm reaction. Moreover, proteins containing a notable set of domains, astacin-like metalloprotease domain and thrombospondin type 1 repeat(s), were found in this fraction. Possible roles in fertilization as well as localizations and behaviors of these proteins are discussed. PMID:26223815

  2. ANISEED 2015: a digital framework for the comparative developmental biology of ascidians.

    PubMed

    Brozovic, Matija; Martin, Cyril; Dantec, Christelle; Dauga, Delphine; Mendez, Mickaël; Simion, Paul; Percher, Madeline; Laporte, Baptiste; Scornavacca, Céline; Di Gregorio, Anna; Fujiwara, Shigeki; Gineste, Mathieu; Lowe, Elijah K; Piette, Jacques; Racioppi, Claudia; Ristoratore, Filomena; Sasakura, Yasunori; Takatori, Naohito; Brown, Titus C; Delsuc, Frédéric; Douzery, Emmanuel; Gissi, Carmela; McDougall, Alex; Nishida, Hiroki; Sawada, Hitoshi; Swalla, Billie J; Yasuo, Hitoyoshi; Lemaire, Patrick

    2016-01-01

    Ascidians belong to the tunicates, the sister group of vertebrates and are recognized model organisms in the field of embryonic development, regeneration and stem cells. ANISEED is the main information system in the field of ascidian developmental biology. This article reports the development of the system since its initial publication in 2010. Over the past five years, we refactored the system from an initial custom schema to an extended version of the Chado schema and redesigned all user and back end interfaces. This new architecture was used to improve and enrich the description of Ciona intestinalis embryonic development, based on an improved genome assembly and gene model set, refined functional gene annotation, and anatomical ontologies, and a new collection of full ORF cDNAs. The genomes of nine ascidian species have been sequenced since the release of the C. intestinalis genome. In ANISEED 2015, all nine new ascidian species can be explored via dedicated genome browsers, and searched by Blast. In addition, ANISEED provides full functional gene annotation, anatomical ontologies and some gene expression data for the six species with highest quality genomes. ANISEED is publicly available at: http://www.aniseed.cnrs.fr. PMID:26420834

  3. Microenvironment and phylogenetic diversity of Prochloron inhabiting the surface of crustose didemnid ascidians.

    PubMed

    Nielsen, Daniel A; Pernice, Mathieu; Schliep, Martin; Sablok, Gaurav; Jeffries, Thomas C; Kühl, Michael; Wangpraseurt, Daniel; Ralph, Peter J; Larkum, Anthony W D

    2015-10-01

    The cyanobacterium Prochloron didemni is primarily found in symbiotic relationships with various marine hosts such as ascidians and sponges. Prochloron remains to be successfully cultivated outside of its host, which reflects a lack of knowledge of its unique ecophysiological requirements. We investigated the microenvironment and diversity of Prochloron inhabiting the upper, exposed surface of didemnid ascidians, providing the first insights into this microhabitat. The pH and O2 concentration in this Prochloron biofilm changes dynamically with irradiance, where photosynthetic activity measurements showed low light adaptation (Ek ∼ 80 ± 7 μmol photons m(-2) s(-1)) but high light tolerance. Surface Prochloron cells exhibited a different fine structure to Prochloron cells from cloacal cavities in other ascidians, the principle difference being a central area of many vacuoles dissected by single thylakoids in the surface Prochloron. Cyanobacterial 16S rDNA pyro-sequencing of the biofilm community on four ascidians resulted in 433 operational taxonomic units (OTUs) where on average -85% (65-99%) of all sequence reads, represented by 136 OTUs, were identified as Prochloron via blast search. All of the major Prochloron-OTUs clustered into independent, highly supported phylotypes separate from sequences reported for internal Prochloron, suggesting a hitherto unexplored genetic variability among Prochloron colonizing the outer surface of didemnids. PMID:26176189

  4. Natural Products from Antarctic Colonial Ascidians of the Genera Aplidium and Synoicum: Variability and Defensive Role

    PubMed Central

    Núñez-Pons, Laura; Carbone, Marianna; Vázquez, Jennifer; Rodríguez, Jaime; Nieto, Rosa María; Varela, María Mercedes; Gavagnin, Margherita; Avila, Conxita

    2012-01-01

    Ascidians have developed multiple defensive strategies mostly related to physical, nutritional or chemical properties of the tunic. One of such is chemical defense based on secondary metabolites. We analyzed a series of colonial Antarctic ascidians from deep-water collections belonging to the genera Aplidium and Synoicum to evaluate the incidence of organic deterrents and their variability. The ether fractions from 15 samples including specimens of the species A. falklandicum, A. fuegiense, A. meridianum, A. millari and S. adareanum were subjected to feeding assays towards two relevant sympatric predators: the starfish Odontaster validus, and the amphipod Cheirimedon femoratus. All samples revealed repellency. Nonetheless, some colonies concentrated defensive chemicals in internal body-regions rather than in the tunic. Four ascidian-derived meroterpenoids, rossinones B and the three derivatives 2,3-epoxy-rossinone B, 3-epi-rossinone B, 5,6-epoxy-rossinone B, and the indole alkaloids meridianins A–G, along with other minoritary meridianin compounds were isolated from several samples. Some purified metabolites were tested in feeding assays exhibiting potent unpalatabilities, thus revealing their role in predation avoidance. Ascidian extracts and purified compound-fractions were further assessed in antibacterial tests against a marine Antarctic bacterium. Only the meridianins showed inhibition activity, demonstrating a multifunctional defensive role. According to their occurrence in nature and within our colonial specimens, the possible origin of both types of metabolites is discussed. PMID:23015772

  5. An ascidian RING finger gene is specifically expressed in a single cell of larval ocellus.

    PubMed

    Sun, Xutong; Okuyama, Makiko; Miyazaki, Katsumi; Zhang, Shicui; Wada, Hiroshi

    2003-07-17

    The ascidian nervous system is extremely simple, although the structure of it is comparable with the complex vertebrate nervous system. This simplicity makes the ascidian nervous system a good model to understand how the neuronal circuit is built up in the chordate nervous system. In order to study the formation of the neuronal circuit at the single cell level, molecular markers to characterize specific single cells are desired. In the present paper, we describe the gene expression pattern of CIGL: an ascidian homologue of Goliath, a Drosophila RING-finger gene. In the early embryonic stage, CiGl is expressed in the lateral part of the neural tube and in several peripheral nerve cells. Later in the larval stage, CiGl specifically marks ocellus: one of the pigment cells in the ascidian brain, which is involved in the photoreceptive system. CiGl will be useful to understand the differentiation mechanism of ocellus, and especially to test the model proposed by. In addition, the finding of this single cells specific gene expression pattern at a certain developmental stage encourages us to look for more genes which mark single cells, especially those that have not been well characterized. PMID:12909346

  6. ANISEED 2015: a digital framework for the comparative developmental biology of ascidians

    PubMed Central

    Brozovic, Matija; Martin, Cyril; Dantec, Christelle; Dauga, Delphine; Mendez, Mickaël; Simion, Paul; Percher, Madeline; Laporte, Baptiste; Scornavacca, Céline; Di Gregorio, Anna; Fujiwara, Shigeki; Gineste, Mathieu; Lowe, Elijah K.; Piette, Jacques; Racioppi, Claudia; Ristoratore, Filomena; Sasakura, Yasunori; Takatori, Naohito; Brown, Titus C.; Delsuc, Frédéric; Douzery, Emmanuel; Gissi, Carmela; McDougall, Alex; Nishida, Hiroki; Sawada, Hitoshi; Swalla, Billie J.; Yasuo, Hitoyoshi; Lemaire, Patrick

    2016-01-01

    Ascidians belong to the tunicates, the sister group of vertebrates and are recognized model organisms in the field of embryonic development, regeneration and stem cells. ANISEED is the main information system in the field of ascidian developmental biology. This article reports the development of the system since its initial publication in 2010. Over the past five years, we refactored the system from an initial custom schema to an extended version of the Chado schema and redesigned all user and back end interfaces. This new architecture was used to improve and enrich the description of Ciona intestinalis embryonic development, based on an improved genome assembly and gene model set, refined functional gene annotation, and anatomical ontologies, and a new collection of full ORF cDNAs. The genomes of nine ascidian species have been sequenced since the release of the C. intestinalis genome. In ANISEED 2015, all nine new ascidian species can be explored via dedicated genome browsers, and searched by Blast. In addition, ANISEED provides full functional gene annotation, anatomical ontologies and some gene expression data for the six species with highest quality genomes. ANISEED is publicly available at: http://www.aniseed.cnrs.fr. PMID:26420834

  7. Identification of testis-specific ubiquitin-conjugating enzyme in the ascidian Ciona intestinalis.

    PubMed

    Yokota, Naoto; Harada, Yoshito; Sawada, Hitoshi

    2010-07-01

    The ubiquitin-proteasome system is known to play a key role in fertilization in ascidians, sea urchins, and mammals. To obtain insights into the ubiquitin-conjugating enzymes (Ube2) involved in reproductive systems, we systematically explored Ube2 enzymes expressed in the testis of the ascidian Ciona intestinalis. Here, we report cDNA cloning and characterization of a novel type of Ube2r (Ci0100152677) that is capable of making a thiolester bond with ubiquitin. Northern analysis, whole-mount in situ hybridization and immunocytochemistry indicate that this enzyme is exclusively expressed in the testis, mainly in the germ cells during the late stage of spermatogenesis, and is localized in the sperm head and tail, suggesting possible participation in fertilization or spermatogenesis/spermiogenesis. PMID:20578064

  8. When shape matters: strategies of different Antarctic ascidians morphotypes to deal with sedimentation.

    PubMed

    Torre, Luciana; Abele, Doris; Lagger, Cristian; Momo, Fernando; Sahade, Ricardo

    2014-08-01

    Climate change leads to increased melting of tidewater glaciers in the Western Antarctic Peninsula region and sediment bearing glacial melt waters negatively affects filter feeding species as solitary ascidians. In previous work the erect-forms Molgula pedunculata and Cnemidocarpa verrucosa (Order Stolidobranchiata) appeared more sensitive than the flat form Ascidia challengeri (Order Phlebobranchiata). Sedimentation exposure is expected to induce up-regulation of anaerobic metabolism by obstructing the organs of gas exchange (environmental hypoxia) or causes enhanced squirting activity (functional hypoxia). In this study we evaluated the possible relationship between ascidian morphotype and their physiological response to sedimentation. Together with some behavioural observations, we analysed the response of anaerobic metabolic parameters (lactate formation and glycogen consumption) in different tissues of three Antarctic ascidians, exposed to high sediment concentrations (200 mgL(-1)). The results were compared to experimental hypoxia (10% pO2) and exercise (induced muscular contraction) effects, in order to discriminate the effect of sediment on each species and morpho-type (erect vs. flat forms). Our results suggest that the styled (erect) C. verrucosa increases muscular squirting activity in order to expulse excessive material, while the flat-form A. challengeri reacts more passively by down-regulating its aerobic metabolism under sediment exposure. Contrary, the erect ascidian M. pedunculata did not show any measurable response to the treatments, indicating that filtration and ingestion activities were not reduced or altered even under high sedimentation (low energetic material) which could be disadvantageous on the long-term and could explain why M. pedunculata densities decline in the study area. PMID:24986145

  9. Quinone and Hydroquinone Metabolites from the Ascidians of the Genus Aplidium

    PubMed Central

    Bertanha, Camila Spereta; Januário, Ana Helena; Alvarenga, Tavane Aparecida; Pimenta, Letícia Pereira; e Silva, Márcio Luis Andrade; Cunha, Wilson Roberto; Pauletti, Patrícia Mendonça

    2014-01-01

    Ascidians of the genus Aplidium are recognized as an important source of chemical diversity and bioactive natural products. Among the compounds produced by this genus are non-nitrogenous metabolites, mainly prenylated quinones and hydroquinones. This review discusses the isolation, structural elucidation, and biological activities of quinones, hydroquinones, rossinones, longithorones, longithorols, floresolides, scabellones, conicaquinones, aplidinones, thiaplidiaquinones, and conithiaquinones. A compilation of the 13C-NMR spectral data of these compounds is also presented. PMID:24927227

  10. Distribution and Localised Effects of the Invasive Ascidian Didemnum perlucidum (Monniot 1983) in an Urban Estuary.

    PubMed

    Simpson, Tiffany Schenk; Wernberg, Thomas; McDonald, Justin I

    2016-01-01

    Didemnid ascidians are notorious marine invaders, fouling infrastructure in many ecosystems globally. However, there have been few reports of direct interactions with native species in their natural environment. The invasive colonial ascidian Didemnum perlucidum was discovered in the Swan River estuary (Western Australia) growing on the native seagrass Halophila ovalis. Given the known effects of other related Didemnum species it was expected that D. perlucidum could adversely affect the seagrass, with possible flow on effects to the rest of the ecosystem. This study aimed to document the distribution and abundance of D. perlucidum in the estuary, and to determine whether this species had a negative impact on H. ovalis or associated flora and fauna. D. perlucidum was largely present near areas of infrastructure, particularly mooring buoys, suggesting these were the source of D. perlucidum recruits on the seagrasses. It showed a clear seasonal pattern in abundance, with highly variable cover and colony size. D. perlucidum had a measurable effect on H. ovalis, with colonies enveloping all plant tissue, likely restricting the photosynthetic ability of individual leaves and total plant biomass. There were also significantly less seagrass-associated mud snails (Batillaria australis) where D. perlucidum cover was high. These results demonstrate the ability of invasive ascidians to colonise and affect native seagrasses and associated biota. Seagrasses are pivotal to the ecological function of many urban estuaries world-wide. Biodiversity in these systems is already vulnerable to multiple stressors from human activities but the potential stress of fouling ascidians may pose an additional and increasing threat in the future. PMID:27144600

  11. Distribution and Localised Effects of the Invasive Ascidian Didemnum perlucidum (Monniot 1983) in an Urban Estuary

    PubMed Central

    Wernberg, Thomas; McDonald, Justin I.

    2016-01-01

    Didemnid ascidians are notorious marine invaders, fouling infrastructure in many ecosystems globally. However, there have been few reports of direct interactions with native species in their natural environment. The invasive colonial ascidian Didemnum perlucidum was discovered in the Swan River estuary (Western Australia) growing on the native seagrass Halophila ovalis. Given the known effects of other related Didemnum species it was expected that D. perlucidum could adversely affect the seagrass, with possible flow on effects to the rest of the ecosystem. This study aimed to document the distribution and abundance of D. perlucidum in the estuary, and to determine whether this species had a negative impact on H. ovalis or associated flora and fauna. D. perlucidum was largely present near areas of infrastructure, particularly mooring buoys, suggesting these were the source of D. perlucidum recruits on the seagrasses. It showed a clear seasonal pattern in abundance, with highly variable cover and colony size. D. perlucidum had a measurable effect on H. ovalis, with colonies enveloping all plant tissue, likely restricting the photosynthetic ability of individual leaves and total plant biomass. There were also significantly less seagrass-associated mud snails (Batillaria australis) where D. perlucidum cover was high. These results demonstrate the ability of invasive ascidians to colonise and affect native seagrasses and associated biota. Seagrasses are pivotal to the ecological function of many urban estuaries world-wide. Biodiversity in these systems is already vulnerable to multiple stressors from human activities but the potential stress of fouling ascidians may pose an additional and increasing threat in the future. PMID:27144600

  12. THALIACEANS, THE NEGLECTED PELAGIC RELATIVES OF ASCIDIANS: A DEVELOPMENTAL AND EVOLUTIONARY ENIGMA.

    PubMed

    Piette, Jacques; Lemaire, Patrick

    2015-06-01

    Most developmental biologists equate tunicates to the sessile ascidians, including Ciona intestinalis, and the pelagic appendicularians, in particular Oikopleura dioica. However, there exists a third group of tunicates with a pelagic lifestyle, the thaliaceans, which include salps, pyrosomes, and doliolids. Although thaliaceans have raised the curiosity offamous zoologists since the 18th century, the difficulty of observing and experimentally manipulating them has led to many controversies and speculations about their life cycles and developmental strategies, the phylogenetic relationship within the group and with other tunicates, and the drivers of speciation in these widely distributed animals living in a seemingly uniform environment. Here, we take a historical perspective to summarize 250 years of work on this intriguing group of animals, and explore how modern genomics and imaging approaches are starting to solve fascinating evolutionary and developmental riddles. Recent molecular analyses support previous morphological evidence that ascidians are not monophyletic and that thaliaceans evolved from a sessile ascidian-like ancestor. In parallel, preliminary live-imaging and gene-expression data offer exciting entry points to understand how the adoption of a pelagic lifestyle led to drastic modifications in the morphology, embryology, and life cycle of these tunicates, compared to their sessile ancestor. PMID:26285352

  13. Spermiotoxicity of nickel nanoparticles in the marine invertebrate Ciona intestinalis (ascidians).

    PubMed

    Gallo, Alessandra; Boni, Raffaele; Buttino, Isabella; Tosti, Elisabetta

    2016-10-01

    Nickel nanoparticles (Ni NPs) are increasingly used in modern industries as catalysts, sensors, and in electronic applications. Due to this large use, their inputs into marine environment have significantly increased; however, the potential ecotoxicological effects in marine environment have so far received little attention. In particular, little is known on the impact of NPs on gamete quality of marine organisms and on the consequences on fertility potential. The present study examines, for the first time, the impact of Ni NPs exposure on sperm quality of the marine invertebrate Ciona intestinalis (ascidian). Several parameters related with sperm status such as plasma membrane lipid peroxidation, mitochondrial membrane potential (MMP), intracellular pH, DNA integrity, and fertilizing ability were assessed as toxicity end points after exposure to different Ni NPs concentrations. Ni NPs generate oxidative stress that in turn induces lipid peroxidation and DNA fragmentation, and alters MMP and sperm morphology. Furthermore, sperm exposure to Ni NPs affects their fertilizing ability and causes developmental anomalies in the offspring. All together, these results reveal a spermiotoxicity of Ni NPs in ascidians suggesting that the application of these NPs should be carefully assessed as to their potential toxic effects on the health of marine organisms that, in turn, may influence the ecological system. This study shows that ascidian sperm represent a suitable and sensitive tool for the investigation of the toxicity of NPs entered into marine environment, for defining the mechanisms of toxic action and for the environmental monitoring purpose. PMID:27080039

  14. Spermiotoxicity of nickel nanoparticles in the marine invertebrate Ciona intestinalis (ascidians)

    PubMed Central

    Gallo, Alessandra; Boni, Raffaele; Buttino, Isabella; Tosti, Elisabetta

    2016-01-01

    Abstract Nickel nanoparticles (Ni NPs) are increasingly used in modern industries as catalysts, sensors, and in electronic applications. Due to this large use, their inputs into marine environment have significantly increased; however, the potential ecotoxicological effects in marine environment have so far received little attention. In particular, little is known on the impact of NPs on gamete quality of marine organisms and on the consequences on fertility potential. The present study examines, for the first time, the impact of Ni NPs exposure on sperm quality of the marine invertebrate Ciona intestinalis (ascidian). Several parameters related with sperm status such as plasma membrane lipid peroxidation, mitochondrial membrane potential (MMP), intracellular pH, DNA integrity, and fertilizing ability were assessed as toxicity end points after exposure to different Ni NPs concentrations. Ni NPs generate oxidative stress that in turn induces lipid peroxidation and DNA fragmentation, and alters MMP and sperm morphology. Furthermore, sperm exposure to Ni NPs affects their fertilizing ability and causes developmental anomalies in the offspring. All together, these results reveal a spermiotoxicity of Ni NPs in ascidians suggesting that the application of these NPs should be carefully assessed as to their potential toxic effects on the health of marine organisms that, in turn, may influence the ecological system. This study shows that ascidian sperm represent a suitable and sensitive tool for the investigation of the toxicity of NPs entered into marine environment, for defining the mechanisms of toxic action and for the environmental monitoring purpose. PMID:27080039

  15. Quantitative and in toto imaging in ascidians: working towards an image-centric systems biology of chordate morphogenesis

    PubMed Central

    Veeman, Michael; Reeves, Wendy

    2015-01-01

    Developmental biology relies heavily on microscopy to image the finely-controlled cell behaviors that drive embryonic development. Most embryos are large enough that a field of view with the resolution and magnification needed to resolve single cells will not span more than a small region of the embryo. Ascidian embryos, however, are sufficiently small that they can be imaged in toto with fine subcellular detail using conventional microscopes and objectives. Unlike other model organisms with particularly small embryos, ascidians have a chordate embryonic body plan that includes a notochord, hollow dorsal neural tube, heart primordium and numerous other anatomical details conserved with the vertebrates. Here we compare the size and anatomy of ascidian embryos with those of more traditional model organisms, and relate these features to the capabilities of both conventional and exotic imaging methods. We review the emergence of Ciona and related ascidian species as model organisms for a new era of image-based developmental systems biology. We conclude by discussing some important challenges in ascidian imaging and image analysis that remain to be solved. PMID:25262824

  16. Nitric Oxide Acts as a Positive Regulator to Induce Metamorphosis of the Ascidian Herdmania momus

    PubMed Central

    Ueda, Nobuo; Degnan, Sandie M.

    2013-01-01

    Marine invertebrates commonly have a biphasic life cycle in which the metamorphic transition from a pelagic larva to a benthic post-larva is mediated by the nitric oxide signalling pathway. Nitric oxide (NO) is synthesised by nitric oxide synthase (NOS), which is a client protein of the molecular chaperon heat shock protein 90 (HSP90). It is notable, then, that both NO and HSP90 have been implicated in regulating metamorphosis in marine invertebrates as diverse as urochordates, echinoderms, molluscs, annelids, and crustaceans. Specifically, the suppression of NOS activity by the application of either NOS- or HSP90-inhibiting pharmacological agents has been shown consistently to induce the initiation of metamorphosis, leading to the hypothesis that a negative regulatory role of NO is widely conserved in biphasic life cycles. Further, the induction of metamorphosis by heat-shock has been demonstrated for multiple species. Here, we investigate the regulatory role of NO in induction of metamorphosis of the solitary tropical ascidian, Herdmania momus. By coupling pharmacological treatments with analysis of HmNOS and HmHSP90 gene expression, we present compelling evidence of a positive regulatory role for NO in metamorphosis of this species, in contrast to all existing ascidian data that supports the hypothesis of NO as a conserved negative regulator of metamorphosis. The exposure of competent H. momus larvae to a NOS inhibitor or an NO donor results in an up-regulation of NOS and HSP90 genes. Heat shock of competent larvae induces metamorphosis in a temperature dependent manner, up to a thermal tolerance that approaches 35°C. Both larval/post-larval survival and the appearance of abnormal morphologies in H. momus post-larvae reflect the magnitude of up-regulation of the HSP90 gene in response to heat-shock. The demonstrated role of NO as a positive metamorphic regulator in H. momus suggests the existence of inter-specific adaptations of NO regulation in ascidian

  17. Ascidian Mitogenomics: Comparison of Evolutionary Rates in Closely Related Taxa Provides Evidence of Ongoing Speciation Events

    PubMed Central

    Griggio, Francesca; Voskoboynik, Ayelet; Iannelli, Fabio; Justy, Fabienne; Tilak, Marie-Ka; Xavier, Turon; Pesole, Graziano; Douzery, Emmanuel J.P.; Mastrototaro, Francesco; Gissi, Carmela

    2014-01-01

    Ascidians are a fascinating group of filter-feeding marine chordates characterized by rapid evolution of both sequences and structure of their nuclear and mitochondrial genomes. Moreover, they include several model organisms used to investigate complex biological processes in chordates. To study the evolutionary dynamics of ascidians at short phylogenetic distances, we sequenced 13 new mitogenomes and analyzed them, together with 15 other available mitogenomes, using a novel approach involving detailed whole-mitogenome comparisons of conspecific and congeneric pairs. The evolutionary rate was quite homogeneous at both intraspecific and congeneric level, and the lowest congeneric rates were found in cryptic (morphologically undistinguishable) and in morphologically very similar species pairs. Moreover, congeneric nonsynonymous rates (dN) were up to two orders of magnitude higher than in intraspecies pairs. Overall, a clear-cut gap sets apart conspecific from congeneric pairs. These evolutionary peculiarities allowed easily identifying an extraordinary intraspecific variability in the model ascidian Botryllus schlosseri, where most pairs show a dN value between that observed at intraspecies and congeneric level, yet consistently lower than that of the Ciona intestinalis cryptic species pair. These data suggest ongoing speciation events producing genetically distinct B. schlosseri entities. Remarkably, these ongoing speciation events were undetectable by the cox1 barcode fragment, demonstrating that, at low phylogenetic distances, the whole mitogenome has a higher resolving power than cox1. Our study shows that whole-mitogenome comparative analyses, performed on a suitable sample of congeneric and intraspecies pairs, may allow detecting not only cryptic species but also ongoing speciation events. PMID:24572017

  18. Microbial diversity of biofilm communities in microniches associated with the didemnid ascidian Lissoclinum patella

    PubMed Central

    Behrendt, Lars; Larkum, Anthony W D; Trampe, Erik; Norman, Anders; Sørensen, Søren J; Kühl, Michael

    2012-01-01

    We assessed the microbial diversity and microenvironmental niche characteristics in the didemnid ascidian Lissoclinum patella using 16S rRNA gene sequencing, microsensor and imaging techniques. L. patella harbors three distinct microbial communities spatially separated by few millimeters of tunic tissue: (i) a biofilm on its upper surface exposed to high irradiance and O2 levels, (ii) a cloacal cavity dominated by the prochlorophyte Prochloron spp. characterized by strong depletion of visible light and a dynamic chemical microenvironment ranging from hyperoxia in light to anoxia in darkness and (iii) a biofilm covering the underside of the animal, where light is depleted of visible wavelengths and enriched in near-infrared radiation (NIR). Variable chlorophyll fluorescence imaging demonstrated photosynthetic activity, and hyperspectral imaging revealed a diversity of photopigments in all microhabitats. Amplicon sequencing revealed the dominance of cyanobacteria in all three layers. Sequences representing the chlorophyll d containing cyanobacterium Acaryochloris marina and anoxygenic phototrophs were abundant on the underside of the ascidian in shallow waters but declined in deeper waters. This depth dependency was supported by a negative correlation between A. marina abundance and collection depth, explained by the increased attenuation of NIR as a function of water depth. The combination of microenvironmental analysis and fine-scale sampling techniques used in this investigation gives valuable first insights into the distribution, abundance and diversity of bacterial communities associated with tropical ascidians. In particular, we show that microenvironments and microbial diversity can vary significantly over scales of a few millimeters in such habitats; which is information easily lost by bulk sampling. PMID:22134643

  19. Aliiroseovarius pelagivivens gen. nov., sp. nov., isolated from seawater, and reclassification of three species of the genus Roseovarius as Aliiroseovarius crassostreae comb. nov., Aliiroseovarius halocynthiae comb. nov. and Aliiroseovarius sediminilitoris comb. nov.

    PubMed

    Park, Sooyeon; Park, Ji-Min; Kang, Chul-Hyung; Yoon, Jung-Hoon

    2015-08-01

    A Gram-stain-negative, non-motile, aerobic and ovoid or rod-shaped bacterium, designated GYSW-22T, was isolated from seawater off Geoje Island in the South Sea, South Korea. Strain GYSW-22T grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 1.0-2.0% (w/v) NaCl. Neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences showed that strain GYSW-22T and the type strains of Roseovarius crassostreae, Roseovarius halocynthiae and Roseovarius sediminilitoris form a coherent cluster, independent of phylogenetic lineages or clusters comprising the type strains of other species of the genus Roseovarius. Strain GYSW-22T exhibited 16S rRNA gene sequence similarities of 97.2, 96.6 and 96.3% to R. halocynthiae MA1-10T, R. crassostreae CV919-312T and R. sediminilitoris M-M10T, respectively, and of 92.6-94.7% to the type strains of other species of the genus Roseovarius. Strain GYSW-22T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c as the major fatty acid. The major polar lipids were phosphatidylcholine, phosphatidylglycerol, one unidentified aminolipid and one unidentified lipid. The DNA G+C content of strain GYSW-22T was 59.0 mol% and its mean DNA-DNA relatedness value with R. halocynthiae MA1-10T was 15 %. On the basis of the data presented, we propose strain GYSW-22T represents a novel species of a new genus, Aliiroseovarius pelagivivens gen. nov., sp. nov. The type strain of the type species is GYSW-22T ( = KCTC 42459T = CECT 8811T). In this study, it is also proposed that Roseovarius crassostreae, Roseovarius halocynthiae and Roseovarius sediminilitoris be reclassified into the new genus as Aliiroseovarius crassostreae comb. nov. (type strain CV919-312T = ATCC BAA-1102T = DSM 16950T), Aliiroseovarius halocynthiae comb. nov. (type strain MA1-10T = KCTC 23462T = CCUG 60745T) and Aliiroseovarius sediminilitoris comb. nov. (type strain M-M10T = KCTC 23959T

  20. Sagitol D, a New Thiazole Containing Pyridoacridine Alkaloid from a Vietnamese Ascidian.

    PubMed

    Utkina, Natalia K

    2015-09-01

    A new thiazole containing pyridoacridine alkaloid, named sagitol D (1), and five known alkaloids kuanoniaminesA (2), C (3), D (4), E (5), and F (6), have been isolated from an unidentified Vietnamese ascidian. The structure of the new compound was established from NMR spectroscopic data. Kuanoniamines C, D, E, and F showed moderate antioxidant activity in the DPPH (IC50 36 µM) and ABTS assays (TE = 0.5), while sagitol D showed weak activity (IC50 92 M;TE = 0.10), and kuanoniamine A was inactive. PMID:26594755

  1. The alien ascidian Styela clava now invading the Sea of Marmara (Tunicata: Ascidiacea)

    PubMed Central

    Çinar, Melih Ertan

    2016-01-01

    Abstract During the implementation of a large project aimed to investigate the benthic community structures of the Sea of Marmara, specimens of the invasive ascidian species Styela clava were collected on natural substrata (rocks) at 10 m depth at one locality (Karamürsel) in İzmit Bay. The specimens were mature, containing gametes, indicating that the species had become established in the area. The Sea of Marmara seems to provide suitable conditions for this species to survive and form proliferating populations. PMID:27047235

  2. The alien ascidian Styela clava now invading the Sea of Marmara (Tunicata: Ascidiacea).

    PubMed

    Çinar, Melih Ertan

    2016-01-01

    During the implementation of a large project aimed to investigate the benthic community structures of the Sea of Marmara, specimens of the invasive ascidian species Styela clava were collected on natural substrata (rocks) at 10 m depth at one locality (Karamürsel) in İzmit Bay. The specimens were mature, containing gametes, indicating that the species had become established in the area. The Sea of Marmara seems to provide suitable conditions for this species to survive and form proliferating populations. PMID:27047235

  3. Peptidolipins B-F, Antibacterial Lipopeptides from an Ascidian-derived Nocardia sp

    PubMed Central

    Wyche, Thomas P.; Hou, Yanpeng; Vazquez-Rivera, Emmanuel; Braun, Doug; Bugni, Tim S.

    2012-01-01

    A marine Nocardia sp. isolated from the ascidian Trididemnum orbiculatum was found to produce five new lipopeptides, peptidolipins B-F (1–5), which show distinct similarities to the previously reported L-Val(6) analog of peptidolipin NA. Synthetic modification of peptidolipin E (4) was used to determine the location of an olefin within the lipid chain. Advanced Marfey’s method was used to determine the absolute configurations of the amino acids. Peptidolipins B (1) and E (4) demonstrated moderate antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA). PMID:22482367

  4. Significant reduction in allergenicity of ovalbumin from chicken egg white following treatment with ascidian viscera N-acetylglucosaminidase.

    PubMed

    Hwang, Hye Seong; Park, Heajin; Kim, Jihye; Choi, Jai Yeon; Lee, Young Kwang; Park, Ho-Young; Choi, Hee-Don; Kim, Ha Hyung

    2016-06-17

    Ovalbumin (OA) is the most abundant ingredient of chicken egg-white allergenic proteins. In the present study we investigated the possibility of reducing OA allergenicity by treatment with a natural protein exhibiting N-acetylglucosaminidase (NA) activity. Ascidian is cultivated as a food resource in northeast Asia. The ascidian viscera NA (AVNA) with almost no other exoglycosidases or proteolytic enzymes was isolated by applying size-exclusion chromatography to a protein precipitate of ascidian viscera. Intact OA was mixed with AVNA containing 0.2, 1.0, and 5.0 Units of NA. Anion-exchange chromatography was then used to isolate OA from AVNA-treated OA. The electrophoretic patterns and N-glycans of each isolated OA from AVNA-treated OA (iOA) were analyzed, and the terminal N-acetylglucosamines of iOA were selectively cleaved with no other degradation occurring. A competitive indirect enzyme-linked immunosorbent assay using rabbit anti-OA sera was performed to investigate the allergenicity of iOA, which was found to be significantly reduced depending on the increased NA activity compared to that of intact OA. These results indicate that OA allergenicity was reduced using a simple and mild treatment process with AVNA, and suggest that ascidian NA is an efficient natural protein for reducing the allergenicity of OA without requiring the use of harsh physical treatments or chemical conjugation. PMID:27178210

  5. DNA barcoding of two solitary ascidians, Herdmania momus Savigny, 1816 and Microcosmus squamiger Michaelsen, 1927 from Thoothukudi coast, India.

    PubMed

    Jaffar Ali, H Abdul; Ahmed, N Shabeer

    2016-07-01

    Morphology-based taxonomical studies of ascidians in India are meagre due to lack of ascidian taxonomist and limitations inherent in conventional system-based identification. The use of short fragment of mitochondrial DNA sequence is proving highly useful in identifying species in a situation where, the traditional morphology-based identification is difficult. In the present study, two adult solitary ascidians collected from the Thoothukudi coast were morphologically identified as Herdmania momus Savigny, 1816 and Microcosmus squamiger Michaelsen, 1927. The genomic DNA of these ascidians was isolated, COI gene was amplified, sequenced and submitted to the GenBank under the accession numbers KM058116, KM411616 and KJ944390. Homology search result using BLAST showed that H. momus showed 100% matched with other H. momus, while M. squamiger showed similarity with Pyura herdmani, a member of the same family Pyuridae. The phylogenetic and genetic distance was maximum in interspecies than in intraspecies. These COI sequences will allow the identification of the species through DNA barcoding technique. Here, we report for the first time the COI gene of H. momus, Savigny 1816 from the Indian coast. PMID:26122341

  6. Structure and Configuration of Phosphoeleganin, a Protein Tyrosine Phosphatase 1B Inhibitor from the Mediterranean Ascidian Sidnyum elegans.

    PubMed

    Imperatore, Concetta; Luciano, Paolo; Aiello, Anna; Vitalone, Rocco; Irace, Carlo; Santamaria, Rita; Li, Jia; Guo, Yue-W; Menna, Marialuisa

    2016-04-22

    A new phosphorylated polyketide, phosphoeleganin (1), has been isolated from the Mediterranean ascidian Sidnyum elegans. Its structure and configuration have been determined by extensive use of 2D NMR and microscale chemical degradation and/or derivatization. Phosphoeleganin (1) inhibited the protein tyrosine phosphatase 1B (PTP1B) activity. PMID:27064611

  7. Distinct modes of mitotic spindle orientation align cells in the dorsal midline of ascidian embryos.

    PubMed

    Negishi, Takefumi; Yasuo, Hitoyoshi

    2015-12-01

    The orientation of cell division can have important consequences on the choice of cell fates adopted by each daughter cell as well as on the architecture of the tissue within which the dividing cell resides. We have studied in detail the oriented cell divisions that take place in the dorsal midline of the ascidian embryo. The dorsal midline cells of the ascidian embryo emerge following an asymmetric cell division oriented along the animal-vegetal (A-V) axis. This division generates the NN (Notochord-Neural) cell at the margin and the E (Endoderm) cell more vegetally. Deviating from the default mode of cell division, these sister cells divide again along the A-V axis to generate a column of four cells. We describe these cell divisions in detail. We show that the NN cell mitotic spindle rotates 90° to align along the A-V axis while the E cell spindle forms directly along the axis following the asymmetric migration of its centrosomes. We combine live imaging, embryo manipulations and pharmacological modulation of cytoskeletal elements to address the mechanisms underlying these distinct subcellular behaviours. Our evidence suggests that, in E cells, aster asymmetry together with the E cell shape contribute to the asymmetric centrosome migration. In NN cells, an intrinsic cytoplasmic polarisation of the cell results in the accumulation of dynein to the animal pole side. Our data support a model in which a dynein-dependent directional cytoplasmic pulling force may be responsible for the NN cell spindle rotation. PMID:26452428

  8. Analysis of the Henze precipitate from the blood cells of the ascidian Phallusia mammillata

    NASA Astrophysics Data System (ADS)

    Ciancio, Aurelio; Scippa, Silvia; Nette, Geoffrey; De Vincentiis, Mario

    The Henze precipitate, a peculiar blue-green microparticulate obtained by lysis of the blood cells of the ascidian Phallusia mammillata (Protochordata), was investigated with atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray microanalysis. The precipitate was collected from the Henze solution, an unstable red-brown product obtained by treating blood with distilled water, whose degradation yields a characteristic blue-green product. The microparticulates measured 50-100 µm in diameter and appeared irregular in shape. SEM examination showed smooth, roughly round boundaries. The microparticulate surface examined with AFM appeared as an irregular matrix formed by 70-320-nm-wide mammillate composites, including and embedding small (500-800 nm wide) crystal-like multilayered formations. X- ray analysis showed that the elements present in these same precipitates were mainly C, Si, Al and O. The microparticulate composition appeared close to those of natural waxes or lacquers, embedding amorphous silicates and/or other Si-Al components. The unusual occurrence of Si in ascidian blood and its role are discussed.

  9. Disulfide bridge structure of ascidian trypsin inhibitor I: similarity to Kazal-type inhibitors.

    PubMed

    Kumazaki, T; Ishii, S

    1990-03-01

    The primary structures of ascidian trypsin inhibitors (iso-inhibitors I and II) were reported in the preceding paper (Kumazaki, T. et al. (1990) J. Biochem. 107, 409-413). Both of them have eight half-cystines in a molecule composed of 55 amino acid residues with a sequence showing no extensive homology to other known protease inhibitors. To locate the four disulfide bridges in the molecule, native inhibitor I was digested with thermolysin to yield cystine-containing peptides. The peptides were separated from each other by reversed-phase HPLC. A core peptide still containing six closely located half-cystines (e.g. -Cys-Arg-Cys and -Cys-Cys-) was further digested with Streptomyces griseus trypsin for cleavage of the Arg-Cys bond. On the other hand, the Cys-Cys bond was split by applying manual Edman degradation to the core peptide. Amino acid composition analyses of the resulting cystine peptides allowed us to define the whole disulfide bridge structure in the parent molecule. The topological relation between the disulfide loops and the reactive site suggested that the ascidian trypsin inhibitor may be classified as a member of the Kazal-type inhibitor family. PMID:2111316

  10. Snail mediates medial-lateral patterning of the ascidian neural plate.

    PubMed

    Hudson, Clare; Sirour, Cathy; Yasuo, Hitoyoshi

    2015-07-15

    The ascidian neural plate exhibits a regular, grid-like arrangement of cells. Patterning of the neural plate across the medial-lateral axis is initiated by bilateral sources of Nodal signalling, such that Nodal signalling induces expression of lateral neural plate genes and represses expression of medial neural plate genes. One of the earliest lateral neural plate genes induced by Nodal signals encodes the transcription factor Snail. Here, we show that Snail is a critical downstream factor mediating this Nodal-dependent patterning. Using gain and loss of function approaches, we show that Snail is required to repress medial neural plate gene expression at neural plate stages and to maintain the lateral neural tube genetic programme at later stages. A comparison of these results to those obtained following Nodal gain and loss of function indicates that Snail mediates a subset of Nodal functions. Consistently, overexpression of Snail can partially rescue a Nodal inhibition phenotype. We conclude that Snail is an early component of the gene regulatory network, initiated by Nodal signals, that patterns the ascidian neural plate. PMID:25962578

  11. 3-acetylpyridine-induced degeneration in the adult ascidian neural complex: Reactive and regenerative changes in glia and blood cells.

    PubMed

    Medina, Bianca N S P; Santos de Abreu, Isadora; Cavalcante, Leny A; Silva, Wagner A B; da Fonseca, Rodrigo N; Allodi, Silvana; de Barros, Cintia M

    2015-08-01

    Ascidians are interesting neurobiological models because of their evolutionary position as a sister-group of vertebrates and the high regenerative capacity of their central nervous system (CNS). We investigated the degeneration and regeneration of the cerebral ganglion complex of the ascidian Styela plicata following injection of the niacinamide antagonist 3-acetylpyridine (3AP), described as targeting the CNS of several vertebrates. For the analysis and establishment of a new model in ascidians, the ganglion complex was dissected and prepared for transmission electron microscopy (TEM), routine light microscopy (LM), immunohistochemistry and Western blotting, 1 or 10 days after injection of 3AP. The siphon stimulation test (SST) was used to quantify the functional response. One day after the injection of 3AP, CNS degeneration and recruitment of a non-neural cell type to the site of injury was observed by both TEM and LM. Furthermore, weaker immunohistochemical reactions for astrocytic glial fibrillary acidic protein (GFAP) and neuronal βIII-tubulin were observed. In contrast, the expression of caspase-3, a protein involved in the apoptotic pathway, and the glycoprotein CD34, a marker for hematopoietic stem cells, increased. Ten days after the injection of 3AP, the expression of markers tended toward the original condition. The SST revealed attenuation and subsequent recovery of the reflexes from 1 to 10 days after 3AP. Therefore, we have developed a new method to study ascidian neural degeneration and regeneration, and identified the decreased expression of GFAP and recruitment of blood stem cells to the damaged ganglion as reasons for the success of neuroregeneration in ascidians. PMID:25484282

  12. Urochordate Ascidians Possess a Single Isoform of Aurora Kinase That Localizes to the Midbody via TPX2 in Eggs and Cleavage Stage Embryos

    PubMed Central

    Hebras, Celine; McDougall, Alex

    2012-01-01

    Aurora kinases are key proteins found throughout the eukaryotes that control mitotic progression. Vertebrate Aurora-A and B kinases are thought to have evolved from a single Aurora-kinase isoform closest to that found in present day urochordates. In urochordate ascidians Aurora binds both TPX2 (a vertebrate AURKA partner) and INCENP (a vertebrate AURKB partner) and localizes to centrosomes and spindle microtubules as well as chromosomes and midbody during both meiosis and mitosis. Ascidian Aurora also displays this localization pattern during mitosis in echinoderms, strengthening the idea that non-vertebrate deuterostomes such as the urochordates and echinoderms possess a single form of Aurora kinase that has properties of vertebrate Aurora-kinase A and B. In the ascidian, TPX2 localizes to the centrosome and the spindle poles also as in vertebrates. However, we were surprised to find that TPX2 also localized strongly to the midbody in ascidian eggs and embryos. We thus examined more closely Aurora localization to the midbody by creating two separate point mutations of ascidian Aurora predicted to perturb binding to TPX2. Both forms of mutated Aurora behaved as predicted: neither localized to spindle poles where TPX2 is enriched. Interestingly, neither form of mutated Aurora localized to the midbody where TPX2 is also enriched, suggesting that ascidian Aurora midbody localization required TPX2 binding in ascidians. Functional analysis revealed that inhibition of Aurora kinase with a pharmacological inhibitor or with a dominant negative kinase dead form of Aurora caused cytokinesis failure and perturbed midbody formation during polar body extrusion. Our data support the view that vertebrate Aurora-A and B kinases evolved from a single non-vertebrate deuterostome ancestor. Moreover, since TPX2 localizes to the midbody in ascidian eggs and cleavage stage embryos it may be worthwhile re-assessing whether Aurora A kinase or TPX2 localize to the midbody in eggs and

  13. Unfractionated Heparin and New Heparin Analogues from Ascidians (Chordate-Tunicate) Ameliorate Colitis in Rats*

    PubMed Central

    Belmiro, Celso L. R.; Castelo-Branco, Morgana T. L.; Melim, Leandra M. C.; Schanaider, Alberto; Elia, Celeste; Madi, Kalil; Pavão, Mauro S. G.; de Souza, Heitor S. P.

    2009-01-01

    The anti-inflammatory effect of mammalian heparin analogues, named dermatan sulfate and heparin, isolated from the ascidian Styela plicata was accessed in a TNBS-induced colitis model in rats. Subcutaneous administration of the invertebrate compounds during a 7-day period drastically reduced inflammation as observed by the normalization of the macroscopic and histological characteristics of the colon. At the molecular level, a decrease in the production of TNF-α, TGF-β, and VEGF was observed, as well as a reduction of NF-κB and MAPK kinase activation. At the cellular level, the heparin analogues attenuated lymphocyte and macrophage recruitment and epithelial cell apoptosis. A drastic reduction in collagen-mediated fibrosis was also observed. No hemorrhagic events were observed after glycan treatment. These results strongly indicate the potential therapeutic use of these compounds for the treatment of colonic inflammation with a lower risk of hemorrhage when compared with mammalian heparin. PMID:19258310

  14. Two New Tryptamine Derivatives, Leptoclinidamide and (-)-Leptoclinidamine B, from an Indonesian Ascidian Leptoclinides dubius

    PubMed Central

    Yamazaki, Hiroyuki; Wewengkang, Defny S.; Nishikawa, Teruaki; Rotinsulu, Henki; Mangindaan, Remy E. P.; Namikoshi, Michio

    2012-01-01

    Two new tryptamine-derived alkaloids, named as leptoclinidamide (1) and (-)-leptoclinidamine B (2), were isolated from an Indonesian ascidian Leptoclinides dubius together with C2-α-D-mannosylpyranosyl-L-tryptophan (3). The structure of 1 was assigned on the basis of spectroscopic data for 1 and its N-acetyl derivative (4). Compound 1 was an amide of tryptamine with two β-alanine units. Although the planar structure of 2 is identical to that of the known compound (+)-leptoclinidamine B (5), compound 2 was determined to be the enantiomer of 5 based on amino acid analysis using HPLC methods. Compounds 1 to 4 were evaluated for cytotoxicity against two human cancer cell lines, HCT-15 (colon) and Jurkat (T-cell lymphoma) cells, but none of the compounds showed activity. PMID:22412806

  15. Phenoloxidases in ascidian hemocytes: characterization of the pro-phenoloxidase activating system.

    PubMed

    Parrinello, Nicolò; Arizza, Vincenzo; Chinnici, Cinzia; Parrinello, Daniela; Cammarata, Matteo

    2003-08-01

    The phenoloxidase (PO) activity of the hemocytes lysate supernatant from three ascidians species, assayed by means of 3-methyl-2-benzothiazolinone hydrazone hydrochloride, have been compared. PO-containing hemocytes were identified by a cytochemical reaction and the enzymatic activity measured by a spectrophotometric assay of lysate supernatant from hemocyte populations separated on a discontinuous Percoll density gradient. In Styela plicata, the enzyme appeared to be contained in morula cells only. In Ciona intestinalis, PO activity was shown in univacuolar refractile granulocyte and granular hemocyte. In Phallusia mammillata both compartment cell and granular hemocytes were positive. Enzymatic assay following electrophoretic analysis on polyacrylamide gel electrophoresis (PAGE) or SDS-PAGE indicated that hemocyte lysate presented orthodiphenoloxidase (catecholase) activity. The enzymes from the three species differed in molecular size, activating substances and trypsin sensitivity. PMID:12892750

  16. New GlcNAc/GalNAc-specific lectin from the ascidian Didemnum ternatanum.

    PubMed

    Molchanova, Valentina; Chikalovets, Irina; Li, Wei; Kobelev, Stanislav; Kozyrevskaya, Svetlana; Bogdanovich, Raisa; Howard, Eric; Belogortseva, Natalia

    2005-05-25

    Previously we isolated GlcNAc-specific lectin (DTL) from the ascidian Didemnum ternatanum by affinity chromatography on cross-linked ovalbumin. Here we report the purification and characterization of new D-GlcNAc/D-GalNAc-specific lectin DTL-A from the same ascidian. This lectin was isolated from non-bound cross-linked ovalbumin fraction and further was purified by gel filtration on Sepharose CL-4B, affinity chromatography on GlcNAc-agarose and gel filtration on Superdex 200. SDS-polyacrylamide gel electrophoresis and gel filtration of purified lectin on Sepharose CL-4B indicates that it exists as large aggregates in the native state. Investigations of the carbohydrate specificity of DTL-A by enzyme-linked lectin assay suggest the multi-specificity of this lectin. DTL-A binds BSM, asialo-BSM as well as heparin and dextran sulfate. The binding of DTL-A to BSM was inhibited by monosaccharides D-GlcNAc and D-GalNAc, their alpha- but not beta-anomers. Among polysaccharides and glycoconjugates, DTL-A binding to BSM was effectively inhibited by BSM, asialo-BSM, pronase-treated BSM and synthetic alpha-D-GalNAc-PAA. Fetuin and asialofetuin showed a much lower inhibitory potency, heparin and dextran sulfate were noninhibitory. On the other hand, DTL-A binding to heparin was effectively inhibited by dextran sulfate, fucoidan, whereas BSM showed insignificantly inhibitory effect. DTL-A binding to heparin was not inhibited by D-GlcNAc and D-GalNAc. PMID:15784180

  17. Regeneration of oral siphon pigment organs in the ascidian Ciona intestinalis

    PubMed Central

    Auger, Hélène; Sasakura, Yasunori; Joly, Jean-Stéphane; Jeffery, William R.

    2013-01-01

    Ascidians have powerful capacities for regeneration but the underlying mechanisms are poorly understood. Here we examine oral siphon regeneration in the solitary ascidian Ciona intestinalis. Following amputation, the oral siphon rapidly reforms oral pigment organs (OPO) at its distal margin prior to slower regeneration of proximal siphon parts. The early stages of oral siphon reformation include cell proliferation and re-growth of the siphon nerves, although the neural complex (adult brain and associated organs) is not required for regeneration. Young animals reform OPO more rapidly after amputation than old animals indicating that regeneration is age dependent. UV irradiation, microcautery, and cultured siphon explant experiments indicate that OPOs are replaced as independent units based on local differentiation of progenitor cells within the siphon, rather than by cell migration from a distant source in the body. The typical pattern of eight OPOs and siphon lobes is restored with fidelity after distal amputation of the oral siphon, but as many as 16 OPOs and lobes can be reformed following proximal amputation near the siphon base. Thus, the pattern of OPO regeneration is determined by cues positioned along the proximal distal axis of the oral siphon. A model is presented in which columns of siphon tissue along the proximal–distal axis below pre-existing OPO are responsible for reproducing the normal OPO pattern during regeneration. This study reveals previously unknown principles of oral siphon and OPO regeneration that will be important for developing Ciona as a regeneration model in urochordates, which may be the closest living relatives of vertebrates. PMID:20059994

  18. In Vitro Acylation of Okadaic Acid in the Presence of Various Bivalves’ Extracts

    PubMed Central

    Konoki, Keiichi; Onoda, Tatsuya; Watanabe, Ryuichi; Cho, Yuko; Kaga, Shinnosuke; Suzuki, Toshiyuki; Yotsu-Yamashita, Mari

    2013-01-01

    The dinoflagellate Dinophysis spp. is responsible for diarrhetic shellfish poisoning (DSP). In the bivalves exposed to the toxic bloom of the dinoflagellate, dinophysistoxin 3 (DTX3), the 7-OH acylated form of either okadaic acid (OA) or DTX1, is produced. We demonstrated in vitro acylation of OA with palmitoyl CoA in the presence of protein extract from the digestive gland, but not other tissues of the bivalve Mizuhopecten yessoensis. The yield of 7-O-palmitoyl OA reached its maximum within 2 h, was the highest at 37 °C followed by 28 °C, 16 °C and 4 °C and was the highest at pH 8 in comparison with the yields at pH 6 and pH 4. The transformation also proceeded when the protein extract was prepared from the bivalves Corbicula japonica and Crassostrea gigas. The OA binding protein OABP2 identified in the sponge Halichondria okadai was not detected in the bivalve M. yessoensis, the bivalve Mytilus galloprovincialis and the ascidian Halocynthia roretzi, though they are known to accumulate diarrhetic shellfish poisoning toxins. Since DTX3 does not bind to protein phosphatases 1 and 2A, the physiological target for OA and DTXs in mammalian cells, the acylation of DSP toxins would be related to a detoxification mechanism for the bivalve species. PMID:23434830

  19. Polarization of PI3K Activity Initiated by Ooplasmic Segregation Guides Nuclear Migration in the Mesendoderm.

    PubMed

    Takatori, Naohito; Oonuma, Kouhei; Nishida, Hiroki; Saiga, Hidetoshi

    2015-11-01

    Asymmetric localization of RNA is a widely observed mechanism of cell polarization. Using embryos of the ascidian, Halocynthia roretzi, we previously showed that mesoderm and endoderm fates are separated by localization of mRNA encoding a transcription factor, Not, to the future mesoderm-side cytoplasm of the mesendoderm cell through asymmetric positioning of the nucleus. Here, we investigated the mechanism that defines the direction of the nuclear migration. We show that localization of PtdIns(3,4,5)P3 to the future mesoderm region determines the direction of nuclear migration. Localization of PtdIns(3,4,5)P3 was dependent on the localization of PI3Kα to the future mesoderm region. PI3Kα was first localized at the 1-cell stage by the ooplasmic movement. Activity of localized PI3Kα at the 4-cell stage was required for the localization of PI3Kα up to the nuclear migration. Our results provide the scaffold for understanding the chain of causality leading to the separation of germ layer fates. PMID:26555053

  20. Screening for negative effects of candidate ascidian antifoulant compounds on a target aquaculture species, Perna canaliculus Gmelin.

    PubMed

    Cahill, Patrick Louis; Heasman, Kevin; Hickey, Anthony; Mountfort, Douglas; Jeffs, Andrew; Kuhajek, Jeannie

    2013-01-01

    The natural chemical compounds radicicol, polygodial and ubiquinone-10 (Q10) have previously been identified as inhibitors of metamorphosis in ascidian larvae. Accordingly, they have potential as a specific remedy for the costly problem of fouling ascidians in bivalve aquaculture. In this study, these compounds were screened for their effects on the physiological health of an aquaculture species, the green-lipped mussel, Perna canaliculus Gmelin, at or above the 99% effective dose (IC(99)) in ascidians. Three physiological biomarkers of mussel health were screened: growth (increases in shell height and wet weight), condition (condition index) and mitochondrial respirational function (Complex I-mediated respiration, Complex II-mediated respiration, maximum uncoupled respiration, leak respiration, respiratory control ratios and phosphorylation system control ratios). While polygodial and Q10 had no effect on mussel growth or the condition index, radicicol retarded growth and decreased the condition index. Mitochondrial respirational function was unaffected by radicicol and polygodial. Conversely, Q10 enhanced Complex I-mediated respiration, highlighting the fundamental role of this compound in the electron transport system. The present study suggests that polygodial and Q10 do not negatively affect the physiological health of P. canaliculus at the IC(99) in ascidians, while radicicol is toxic. Moreover, Q10 is of benefit in biomedical settings as a cellular antioxidant and therefore may also benefit P. canaliculus. Accordingly, polygodial and Q10 should be progressed to the next stage of testing where possible negative effects on bivalves will be further explored, followed by development of application techniques and testing in a laboratory and aquaculture setting. PMID:23194394

  1. Pibocin B, the first N-O-methylindole marine alkaloid, a metabolite from the Far-Eastern ascidian Eudistoma species.

    PubMed

    Makarieva, T N; Dmitrenok, A S; Dmitrenok, P S; Grebnev, B B; Stonik, V A

    2001-12-01

    Pibocin B (2), the first representative of marine alkaloids with a unique structural feature, an N-O-methylindole group, was isolated from the Far-Eastern ascidian Eudistoma sp. Its structure has been established as (8 beta)-2-bromo-N-O-methyl-6,8-dimethylergoline on the basis of NMR data, FAB and MALDI-TOF MS, and chemical correlations. Pibocin B showed moderate cytotoxic activity against mouse Ehrlich carcinoma cells. PMID:11754612

  2. Microenvironmental Ecology of the Chlorophyll b-Containing Symbiotic Cyanobacterium Prochloron in the Didemnid Ascidian Lissoclinum patella

    PubMed Central

    Kühl, Michael; Behrendt, Lars; Trampe, Erik; Qvortrup, Klaus; Schreiber, Ulrich; Borisov, Sergey M.; Klimant, Ingo; Larkum, Anthony W. D.

    2012-01-01

    The discovery of the cyanobacterium Prochloron was the first finding of a bacterial oxyphototroph with chlorophyll (Chl) b, in addition to Chl a. It was first described as Prochloron didemni but a number of clades have since been described. Prochloron is a conspicuously large (7–25 μm) unicellular cyanobacterium living in a symbiotic relationship, primarily with (sub-) tropical didemnid ascidians; it has resisted numerous cultivation attempts and appears truly obligatory symbiotic. Recently, a Prochloron draft genome was published, revealing no lack of metabolic genes that could explain the apparent inability to reproduce and sustain photosynthesis in a free-living stage. Possibly, the unsuccessful cultivation is partly due to a lack of knowledge about the microenvironmental conditions and ecophysiology of Prochloron in its natural habitat. We used microsensors, variable chlorophyll fluorescence imaging and imaging of O2 and pH to obtain a detailed insight to the microenvironmental ecology and photobiology of Prochloron in hospite in the didemnid ascidian Lissoclinum patella. The microenvironment within ascidians is characterized by steep gradients of light and chemical parameters that change rapidly with varying irradiances. The interior zone of the ascidians harboring Prochloron thus became anoxic and acidic within a few minutes of darkness, while the same zone exhibited O2 super-saturation and strongly alkaline pH after a few minutes of illumination. Photosynthesis showed lack of photoinhibition even at high irradiances equivalent to full sunlight, and photosynthesis recovered rapidly after periods of anoxia. We discuss these new insights on the ecological niche of Prochloron and possible interactions with its host and other microbes in light of its recently published genome and a recent study of the overall microbial diversity and metagenome of L. patella. PMID:23226144

  3. Comparative study on bioremediation of heavy metals by solitary ascidian, Phallusia nigra, between Thoothukudi and Vizhinjam ports of India.

    PubMed

    Abdul Jaffar Ali, H; Tamilselvi, M; Akram, A Soban; Kaleem Arshan, M L; Sivakumar, V

    2015-11-01

    Ascidians belonging to the sub-phylum Uro-chordata are used as potential model organisms in various parts of the world for biosorption of metals. The sedentary nature, filter feeding habits, presence of vanadocytes and the absence of kidneys cause them to accumulate metals. The present study was aimed to compare biosorption of metals such as cadmium, copper, lead, mercury and vanadium in test and mantle body of solitary ascidian Phallusia nigra between two ecologically significant stations such as Thoothukudi (Station 1) and Vizhinjam (Station 2) ports of India. Monthly samplings of water and P. nigra were done for a period of one year from September 2010 to August 2011 and subjected to analysis of metal accumulation. The average metal concentrations except mercury in the Thoothukudi water were found to be higher of comparable magnitudes than the Vizhinjam water. One-way ANOVA showed significant differences between the stations. A comparison of average metal concentrations in the test and mantle body of P. nigra between two stations showed that the enrichment of V, Cd, Pb, Cu and Hg in the Thoothukudi samples may be due to high bioaccumulation factors of these elements as compared to other species of ascidians. The bioaccumulation factors were in the order of V>Pb>Cd>Cu> Hg for the test and mantle body in stations 1 and 2. Application of one-way ANOVA for the concentration of these metals between test and mantle body showed significant differences in both stations. Similarly, ANOVA for biosorption of these trace metals by P. nigra showed significant difference between stations. Metal concentrations recorded in this ascidian could effectively be used as good reference material for monitoring metal contamination in Indian sea waters. PMID:26026676

  4. Ordered expression pattern of Hox and ParaHox genes along the alimentary canal in the ascidian juvenile.

    PubMed

    Nakayama, Satoshi; Satou, Kunihiro; Orito, Wataru; Ogasawara, Michio

    2016-07-01

    The Hox and ParaHox genes of bilateria share a similar expression pattern along the body axis and are known to be associated with anterior-posterior patterning. In vertebrates, the Hox genes are also expressed in presomitic mesoderm and gut endoderm and the ParaHox genes show a restricted expression pattern in the gut-related derivatives. Regional expression patterns in the embryonic central nervous system of the basal chordates amphioxus and ascidian have been reported; however, little is known about their endodermal expression in the alimentary canal. We focus on the Hox and ParaHox genes in the ascidian Ciona intestinalis and investigate the gene expression patterns in the juvenile, which shows morphological regionality in the alimentary canal. Gene expression analyses by using whole-mount in situ hybridization reveal that all Hox genes have a regional expression pattern along the alimentary canal. Expression of Hox1 to Hox4 is restricted to the posterior region of pharyngeal derivatives. Hox5 to Hox13 show an ordered expression pattern correlated with each Hox gene number along the postpharyngeal digestive tract. This expression pattern along the anterior-posterior axis has also been observed in Ciona ParaHox genes. Our observations suggest that ascidian Hox and ParaHox clusters are dispersed; however, the ordered expression patterns along the alimentary canal appear to be conserved among chordates. PMID:26837224

  5. Ecological observations on the colonial ascidian Didemnum sp. in a New England tide pool habitat

    USGS Publications Warehouse

    Valentine, P.C.; Carman, M.R.; Blackwood, D.S.; Heffron, E.J.

    2007-01-01

    The colonial ascidian Didemnum sp. has colonized northwestern Atlantic coastal habitats from southern Long Island, New York, to Eastport, Maine. It is also present in offshore habitats of the Georges Bank fishing grounds. It threatens to alter fisheries habitats and shellfish aquacultures. Observations in a tide pool at Sandwich, MA from December 2003 to February 2006 show that Didemnum sp. tolerates water temperatures ranging from ≤ 1 to > 24 °C, with daily changes of up to 11 °C. It attaches to pebbles, cobbles, and boulders, and it overgrows other tunicates, seaweeds, sponges, and bivalves. From May to mid July, colonies appear as small patches on the bottoms of rocks. Colonies grow rapidly from July to September, with some growth into December, and they range in color from pink to pale yellow to pale orange. Colony health declines from October through April, presumably in response to changes in water temperatures, and this degenerative process is manifested by color changes, by the appearance of small dark brown spots that represent clumps of fecal pellets in the colony, by scavenging by periwinkles, and by a peeling-away of colonies from the sides of cobbles and boulders. At Sandwich, colonies died that were exposed to air at low tide. The species does not exhibit this seasonal cycle of growth and decline in subtidal habitats (40–65 m) on the Georges Bank fishing grounds where the daily climate is relatively stable and annual water temperatures range from 4 to 15 °C. Experiments in the tide pool with small colony fragments (5 to 9 cm2) show they re-attach and grow rapidly by asexual budding, increasing in size 6- to 11-fold in the first 15 days. Didemnum sp. at Sandwich has no known predators except for common periwinkles (Littorina littorea) that graze on degenerating colonies in the October to April time period and whenever colonies are stressed by desiccation. The tendencies of the ascidian (1) to attach to firm substrates, (2) to rapidly overgrow

  6. Evidence of a Native Northwest Atlantic COI Haplotype Clade in the Cryptogenic Colonial Ascidian Botryllus schlosseri.

    PubMed

    Yund, Philip O; Collins, Catherine; Johnson, Sheri L

    2015-06-01

    The colonial ascidian Botryllus schlosseri should be considered cryptogenic (i.e., not definitively classified as either native or introduced) in the Northwest Atlantic. Although all the evidence is quite circumstantial, over the last 15 years most research groups have accepted the scenario of human-mediated dispersal and classified B. schlosseri as introduced; others have continued to consider it native or cryptogenic. We address the invasion status of this species by adding 174 sequences to the growing worldwide database for the mitochondrial gene cytochrome c oxidase subunit I (COI) and analyzing 1077 sequences to compare genetic diversity of one clade of haplotypes in the Northwest Atlantic with two hypothesized source regions (the Northeast Atlantic and Mediterranean). Our results lead us to reject the prevailing view of the directionality of transport across the Atlantic. We argue that the genetic diversity patterns at COI are far more consistent with the existence of at least one haplotype clade in the Northwest Atlantic (and possibly a second) that substantially pre-dates human colonization from Europe, with this native North American clade subsequently introduced to three sites in Northeast Atlantic and Mediterranean waters. However, we agree with past researchers that some sites in the Northwest Atlantic have more recently been invaded by alien haplotypes, so that some populations are currently composed of a mixture of native and invader haplotypes. PMID:26124447

  7. Recurrent phagocytosis-induced apoptosis in the cyclical generation change of the compound ascidian Botryllus schlosseri.

    PubMed

    Franchi, Nicola; Ballin, Francesca; Manni, Lucia; Schiavon, Filippo; Basso, Giuseppe; Ballarin, Loriano

    2016-09-01

    Colonies of the marine, filter-feeding ascidian Botryllus schlosseri undergo cyclical generation changes or takeovers. These events are characterised by the progressive resorption of adult zooids and their replacement by their buds that grow to adult size, open their siphons and start filtering. During the take-over, tissues of adult zooids undergo extensive apoptosis; circulating, spreading phagocytes enter the effete tissues, ingest dying cells acquiring a giant size and a round morphology. Then, phagocytes re-enter the circulation where they represent a considerable fraction (more than 20%) of circulating haemocytes. In this study, we evidence that most of these circulating phagocytes show morphological and biochemical signs of apoptosis. Accordingly, these phagocytes express transcripts of orthologues of the apoptosis-related genes Bax, AIF1 and PARP1. Electron microscopy shows that giant phagocytes contain apoptotic phagocytes inside their own phagocytic vacuole. The transcript of the orthologues of the anti-apoptotic gene IAP7 was detected only in spreading phagocytes, mostly abundant in phases far from the take-over. Therefore, the presented data suggest that, at take-over, phagocytes undergo phagocytosis-induced apoptosis (PIA). In mammals, PIA is assumed to be a process assuring the killing and the complete elimination of microbes, by promoting the disposal of terminally differentiated phagocytes and the resolution of infection. In B. schlosseri, PIA assumes a so far undescribed role, being required for the control of asexual development and colony homeostasis. PMID:27106705

  8. Reprotoxicity of the antifoulant chlorothalonil in ascidians: an ecological risk assessment.

    PubMed

    Gallo, Alessandra; Tosti, Elisabetta

    2015-01-01

    Chlorothalonil is a widely used biocide in antifouling paint formulation that replaces tin-based compounds after their definitive ban. Although chlorothalonil inputs into the marine environment have significantly increased in recent years, little is known about its effect on marine animals and in particular on their reproductive processes. In this line, the aim of the present study was to investigate the effects of chlorothalonil exposure on the gamete physiology, fertilization rate and transmissible damage to offspring in the marine invertebrate Ciona intestinalis (ascidians). To identify a possible mechanism of action of chlorothalonil, electrophysiological techniques were used to study the impact on oocyte membrane excitability and on the electrical events occurring at fertilization. The pre-exposure of spermatozoa and oocytes to chlorothalonil did not affect the fertilization rate but caused damage to the offspring by inducing larval malformation. The highest toxicity was observed when fertilization was performed in chlorothalonil solutions with the lowest EC50 value. In particular, it was observed that low chlorothalonil concentrations interfered with embryo development and led to abnormal larvae, whereas high concentrations arrested embryo formation. In mature oocytes, a decrease in the amplitudes of the sodium and fertilization currents was observed, suggesting an involvement of plasma membrane ion currents in the teratogenic mechanism of chlorothalonil action. The risk estimation confirmed that the predicted no-effect concentration (PNEC) exceeded the predicted effect concentration (PEC), thus indicating that chlorothalonil may pose a risk to aquatic species. PMID:25875759

  9. Global Phylogeography of the Widely Introduced North West Pacific Ascidian Styela clava

    PubMed Central

    Goldstien, Sharyn J.; Dupont, Lise; Viard, Frédérique; Hallas, Paul J.; Nishikawa, Teruaki; Schiel, David R.; Gemmell, Neil J.; Bishop, John D. D.

    2011-01-01

    The solitary ascidian Styela clava Herdman, 1882 is considered to be native to Japan, Korea, northern China and the Russian Federation in the NW Pacific, but it has spread globally over the last 80 years and is now established as an introduced species on the east and west coasts of North America, Europe, Australia and New Zealand. In eastern Canada it reaches sufficient density to be a serious pest to aquaculture concerns. We sequenced a fragment of the cytochrome oxidase subunit I mitochondrial gene (COI) from a total of 554 individuals to examine the genetic relationships of 20 S. clava populations sampled throughout the introduced and native ranges, in order to investigate invasive population characteristics. The data presented here show a moderate level of genetic diversity throughout the northern hemisphere. The southern hemisphere (particularly New Zealand) displays a greater amount of haplotype and nucleotide diversity in comparison. This species, like many other invasive species, shows a range of genetic diversities among introduced populations independent of the age of incursion. The successful establishment of this species appears to be associated with multiple incursions in many locations, while other locations appear to have experienced rapid expansion from a potentially small population with reduced genetic diversity. These contrasting patterns create difficulties when attempting to manage and mitigate a species that continues to spread among ports and marinas around the world. PMID:21364988

  10. Immunotoxicity in ascidians: antifouling compounds alternative to organotins-IV. The case of zinc pyrithione.

    PubMed

    Cima, Francesca; Ballarin, Loriano

    2015-03-01

    New biocides such as the organometallic compound zinc pyrithione (ZnP) have been massively introduced by many countries in formulations of antifouling paints following the ban on tributyltin (TBT). The effects of sublethal concentrations (LC50=82.5 μM, i.e., 26.2 mg/l) on cultured haemocytes of the ascidian Botryllus schlosseri have been investigated and compared with TBT. The percentage of haemocytes with amoeboid morphology and containing phagocytised yeast cells were significantly (p<0.05) reduced after exposure to 0.1 (31.7 μg/l) and 0.5 μM (158 μg/l), respectively. An antagonistic interaction in inducing cytoskeletal alterations was observed when ZnP and TBT were co-present in the exposure medium. ZnP affected only the actin component. As caused by TBT, ZnP induced apoptosis and inhibited both oxidative phosphorylation and lysosomal activities. In contrast to the case of TBT, a decrement in Ca(2+)-ATPase activity and a decrease in cytosolic Ca(2+) were detected after incubation at the highest concentration (1 μM, i.e., 317.7 μg/l) used. In comparison with other antifouling compounds, ZnP shows as much toxicity as TBT to cultured haemocytes at extremely low concentrations interfering with fundamental cell activities. PMID:25576186

  11. Reprotoxicity of the Antifoulant Chlorothalonil in Ascidians: An Ecological Risk Assessment

    PubMed Central

    Gallo, Alessandra; Tosti, Elisabetta

    2015-01-01

    Chlorothalonil is a widely used biocide in antifouling paint formulation that replaces tin-based compounds after their definitive ban. Although chlorothalonil inputs into the marine environment have significantly increased in recent years, little is known about its effect on marine animals and in particular on their reproductive processes. In this line, the aim of the present study was to investigate the effects of chlorothalonil exposure on the gamete physiology, fertilization rate and transmissible damage to offspring in the marine invertebrate Ciona intestinalis (ascidians). To identify a possible mechanism of action of chlorothalonil, electrophysiological techniques were used to study the impact on oocyte membrane excitability and on the electrical events occurring at fertilization. The pre-exposure of spermatozoa and oocytes to chlorothalonil did not affect the fertilization rate but caused damage to the offspring by inducing larval malformation. The highest toxicity was observed when fertilization was performed in chlorothalonil solutions with the lowest EC50 value. In particular, it was observed that low chlorothalonil concentrations interfered with embryo development and led to abnormal larvae, whereas high concentrations arrested embryo formation. In mature oocytes, a decrease in the amplitudes of the sodium and fertilization currents was observed, suggesting an involvement of plasma membrane ion currents in the teratogenic mechanism of chlorothalonil action. The risk estimation confirmed that the predicted no-effect concentration (PNEC) exceeded the predicted effect concentration (PEC), thus indicating that chlorothalonil may pose a risk to aquatic species. PMID:25875759

  12. Study of Cis-regulatory Elements in the Ascidian Ciona intestinalis.

    PubMed

    Irvine, Steven Q

    2013-03-01

    The ascidian (sea squirt) C. intestinalis has become an important model organism for the study of cis-regulation. This is largely due to the technology that has been developed for assessing cis-regulatory activity through the use of transient reporter transgenes introduced into fertilized eggs. This technique allows the rapid and inexpensive testing of endogenous or altered DNA for regulatory activity in vivo. This review examines evidence that C. intestinalis cis-regulatory elements are located more closely to coding regions than in other model organisms. I go on to compare the organization of cis-regulatory elements and conserved non-coding sequences in Ciona, mammals, and other deuterostomes for three representative C.intestinalis genes, Pax6, FoxAa, and the DlxA-B cluster, along with homologs in the other species. These comparisons point out some of the similarities and differences between cis-regulatory elements and their study in the various model organisms. Finally, I provide illustrations of how C. intestinalis lends itself to detailed study of the structure of cis-regulatory elements, which have led, and promise to continue to lead, to important insights into the fundamentals of transcriptional regulation. PMID:23997651

  13. Comprehensive analysis of the ascidian genome reveals novel insights into the molecular evolution of ion channel genes.

    PubMed

    Okamura, Yasushi; Nishino, Atsuo; Murata, Yoshimichi; Nakajo, Koichi; Iwasaki, Hirohide; Ohtsuka, Yukio; Tanaka-Kunishima, Motoko; Takahashi, Nobuyuki; Hara, Yuji; Yoshida, Takashi; Nishida, Motohiro; Okado, Haruo; Watari, Hirofumi; Meinertzhagen, Ian A; Satoh, Nori; Takahashi, Kunitaro; Satou, Yutaka; Okada, Yasunobu; Mori, Yasuo

    2005-08-11

    Ion fluxes through membrane ion channels play crucial roles both in neuronal signaling and the homeostatic control of body electrolytes. Despite our knowledge about the respective ion channels, just how diversification of ion channel genes underlies adaptation of animals to the physical environment remains unknown. Here we systematically survey up to 160 putative ion channel genes in the genome of Ciona intestinalis and compare them with corresponding gene sets from the genomes of the nematode Chaenorhabditis elegans, the fruit fly Drosophila melanogaster, and the more closely related genomes of vertebrates. Ciona has a set of so-called "prototype" genes for ion channels regulating neuronal excitability, or for neurotransmitter receptors, suggesting that genes responsible for neuronal signaling in mammals appear to have diversified mainly via gene duplications of the more restricted members of ancestral genomes before the ascidian/vertebrate divergence. Most genes responsible for modulation of neuronal excitability and pain sensation are absent from the ascidian genome, suggesting that these genes arose after the divergence of urochordates. In contrast, the divergent genes encoding connexins, transient receptor potential-related channels and chloride channels, channels involved rather in homeostatic control, indicate gene duplication events unique to the ascidian lineage. Because several invertebrate-unique channel genes exist in Ciona genome, the crown group of extant vertebrates not only acquired novel channel genes via gene/genome duplications but also discarded some ancient genes that have persisted in invertebrates. Such genome-wide information of ion channel genes in basal chordates enables us to begin correlating the innovation and remodeling of genes with the adaptation of more recent chordates to their physical environment. PMID:15914577

  14. Five new species of lichomolgid copepods associated with ascidians from Korea, with proposal of two new genera (Crustacea, Copepoda, Lichomolgidae)

    NASA Astrophysics Data System (ADS)

    Moon, Seong Yong; Kim, Il-Hoi

    2011-09-01

    Five new species of the family Lichomolgidae associated with solitary ascidians are described from the east coast of Korea. Two new genera are proposed: Protomolgus n. gen. to incorpotate Protomolgus duplex n. sp. and P. singularis n. sp., and Dontimolgus n. gen. to incorporate Dontimolgus brevicaudatus n. sp. Protomolgus n. gen. characteristically has a four-segmented female maxilliped and a bipartite mandible. Dontimolgus n. gen. possesses a large, tooth-like process on the first maxillary segment and three spines on the third exopodal segment of leg 3. Other two new species described are Lichomolgus infirmus n. sp. and L. pectinatus n. sp.

  15. Metamorphosis of the invasive ascidian Ciona savignyi: environmental variables and chemical exposure.

    PubMed

    Cahill, Patrick L; Atalah, Javier; Selwood, Andrew I; Kuhajek, Jeanne M

    2016-01-01

    In this study, the effects of environmental variables on larval metamorphosis of the solitary ascidian Ciona savignyi were investigated in a laboratory setting. The progression of metamorphic changes were tracked under various temperature, photoperiod, substrate, larval density, and vessel size regimes. Metamorphosis was maximised at 18 °C, 12:12 h subdued light:dark, smooth polystyrene substrate, and 10 larvae mL(-1) in a twelve-well tissue culture plate. Eliminating the air-water interface by filling culture vessels to capacity further increased the proportion of metamorphosed larvae; 87 ± 5% of larvae completed metamorphosis within 5 days compared to 45 ± 5% in control wells. The effects of the reference antifouling compounds polygodial, portimine, oroidin, chlorothalonil, and tolylfluanid on C. savignyi were subsequently determined, highlighting (1) the sensitivity of C. savignyi metamorphosis to chemical exposure and (2) the potential to use C. savignyi larvae to screen for bioactivity in an optimised laboratory setting. The compounds were bioactive in the low ng mL(-1) to high µg mL(-1) range. Polygodial was chosen for additional investigations, where it was shown that mean reductions in the proportions of larvae reaching stage E were highly repeatable both within (repeatability = 14 ± 9%) and between (intermediate precision = 17 ± 3%) independent experiments. An environmental extract had no effect on the larvae but exposing larvae to both the extract and polygodial reduced potency relative to polygodial alone. This change in potency stresses the need for caution when working with complex samples, as is routinely implemented when isolating natural compounds from their biological source. Overall, the outcomes of this study highlight the sensitivity of C. savignyi metamorphosis to environmental variations and chemical exposure. PMID:26966668

  16. Metamorphosis of the invasive ascidian Ciona savignyi: environmental variables and chemical exposure

    PubMed Central

    Atalah, Javier; Selwood, Andrew I.; Kuhajek, Jeanne M.

    2016-01-01

    In this study, the effects of environmental variables on larval metamorphosis of the solitary ascidian Ciona savignyi were investigated in a laboratory setting. The progression of metamorphic changes were tracked under various temperature, photoperiod, substrate, larval density, and vessel size regimes. Metamorphosis was maximised at 18 °C, 12:12 h subdued light:dark, smooth polystyrene substrate, and 10 larvae mL−1 in a twelve-well tissue culture plate. Eliminating the air-water interface by filling culture vessels to capacity further increased the proportion of metamorphosed larvae; 87 ± 5% of larvae completed metamorphosis within 5 days compared to 45 ± 5% in control wells. The effects of the reference antifouling compounds polygodial, portimine, oroidin, chlorothalonil, and tolylfluanid on C. savignyi were subsequently determined, highlighting (1) the sensitivity of C. savignyi metamorphosis to chemical exposure and (2) the potential to use C. savignyi larvae to screen for bioactivity in an optimised laboratory setting. The compounds were bioactive in the low ng mL−1 to high µg mL−1 range. Polygodial was chosen for additional investigations, where it was shown that mean reductions in the proportions of larvae reaching stage E were highly repeatable both within (repeatability = 14 ± 9%) and between (intermediate precision = 17 ± 3%) independent experiments. An environmental extract had no effect on the larvae but exposing larvae to both the extract and polygodial reduced potency relative to polygodial alone. This change in potency stresses the need for caution when working with complex samples, as is routinely implemented when isolating natural compounds from their biological source. Overall, the outcomes of this study highlight the sensitivity of C. savignyi metamorphosis to environmental variations and chemical exposure. PMID:26966668

  17. Comparison of whole mitochondrial genome sequences from two clades of the invasive ascidian, Didemnum vexillum.

    PubMed

    Smith, Kirsty F; Abbott, Cathryn L; Saito, Yasunori; Fidler, Andrew E

    2015-02-01

    The mitochondria are the main source of cellular energy production and have an important role in development, fertility, and thermal limitations. Adaptive mitochondrial DNA mutations have the potential to be of great importance in determining aspects of the life history of an organism. Phylogenetic analyses of the globally invasive marine ascidian Didemnum vexillum using the mitochondrial cytochrome c oxidase 1 (COX1) coding region, revealed two distinct clades. Representatives of one clade (denoted by 'B') are geographically restricted to D. vexillum's native region (north-west Pacific Ocean, including Japan), whereas members of the other clade (denoted by 'A') have been introduced and become invasive in temperate coastal areas around the world. Persistence of clade B's restricted distribution may reflect it being inherently less invasive than clade A. To investigate this we sought to determine if the two clades differ significantly in other mitochondrial genes of functional significance, specifically, alterations in amino acids encoded in mitochondrial enzyme subunits. Differences in functional mitochondrial genes could indicate an increased ability for clade A colonies to tolerate a wider range of environmental temperature. Full mitochondrial genomic sequences from D. vexillum clades A and B were obtained and they predict significant sequence differences in genes encoding for enzymes involved in oxidative phosphorylation. Diversity levels were relatively high and showed divergence across almost all genes, with p-distance values between the two clades indicating recent divergence. Both clades showed an excess of rare variants, which is consistent with balancing selection or a recent population expansion. Results presented here will inform future research focusing on examining the functional properties of the corresponding mitochondrial respiration enzymes, of A and B clade enzymes. By comparing closely related taxa that have differing distributions it is possible

  18. The Whereabouts of an Ancient Wanderer: Global Phylogeography of the Solitary Ascidian Styela plicata

    PubMed Central

    Pineda, Mari Carmen; López-Legentil, Susanna; Turon, Xavier

    2011-01-01

    Genetic tools have greatly aided in tracing the sources and colonization history of introduced species. However, recurrent introductions and repeated shuffling of populations may have blurred some of the genetic signals left by ancient introductions. Styela plicata is a solitary ascidian distributed worldwide. Although its origin remains unclear, this species is believed to have spread worldwide by travelling on ship's hulls. The goals of this study were to infer the genetic structure and global phylogeography of S. plicata and to look for present-day and historical genetic patterns. Two genetic markers were used: a fragment of the mitochondrial gene Cytochrome Oxidase subunit I (COI) and a fragment of the nuclear gene Adenine Nucleotide Transporter/ADP-ATP Translocase (ANT). A total of 368 individuals for COI and 315 for ANT were sequenced from 17 locations worldwide. The levels of gene diversity were moderate for COI to high for ANT. The Mediterranean populations showed the least diversity and allelic richness for both markers, while the Indian, Atlantic and Pacific Oceans had the highest gene and nucleotide diversities. Network and phylogenetic analyses with COI and ANT revealed two groups of alleles separated by 15 and 4 mutational steps, respectively. The existence of different lineages suggested an ancient population split. However, the geographic distributions of these groups did not show any consistent pattern, indicating different phylogeographic histories for each gene. Genetic divergence was significant for many population-pairs irrespective of the geographic distance among them. Stochastic introduction events are reflected in the uneven distribution of COI and ANT allele frequencies and groups among many populations. Our results confirmed that S. plicata has been present in all studied oceans for a long time, and that recurrent colonization events and occasional shuffling among populations have determined the actual genetic structure of this species

  19. Verruculides A and B, two new protein tyrosine phosphatase 1B inhibitors from an Indonesian ascidian-derived Penicillium verruculosum.

    PubMed

    Yamazaki, Hiroyuki; Nakayama, Wataru; Takahashi, Ohgi; Kirikoshi, Ryota; Izumikawa, Yuta; Iwasaki, Kohei; Toraiwa, Kengo; Ukai, Kazuyo; Rotinsulu, Henki; Wewengkang, Defny S; Sumilat, Deiske A; Mangindaan, Remy E P; Namikoshi, Michio

    2015-08-15

    Two new merosesquiterpenes, verruculides A (1) and B (2), were isolated from a culture broth of the Indonesian ascidian-derived Penicillium verruculosum TPU1311, together with three known congeners, chrodrimanins A (3), B (4), and H (5). The structures of 1 and 2 were assigned on the basis of their spectroscopic data (1D and 2D NMR, HRMS, UV, CD, and IR). Compound 2 had a linear sesquiterpene moiety and was considered to be the derivative of the biosynthetic precursor for 1 and 3-5. Compounds 1, 3, and 5 inhibited the activity of protein tyrosine phosphatase 1B (PTP1B) with IC50 values of 8.4, 8.5, and 14.9 μM, respectively. Compound 2 showed 40% inhibition at 23.1 μM, while 4 was not active at 20.7 μM. PMID:26115570

  20. A new genus of Asterocheridae (Copepoda: Siphonostomatoida) ectoassociate of the ascidian Eudistoma vannamei Millar, 1977 (Polycitoridae) from Brazil.

    PubMed

    Johnsson, Rodrigo; Bahia, Cristiano; Neves, Elizabeth

    2016-01-01

    Asterocheres Boeck, 1860 is the largest genus of the siphonostomatoid copepod family Asterocheridae, containing 63 valid species. The genus is known for its symbiotic relationships with many marine invertebrate taxa, especially sponges, cnidarians, bryozoans, and echinoderms. Recent studies have restricted the diagnosis of this genus. Consequently, many species are now considered as species inquirendae. The present paper describes a new species living externally on the tunic of Eudistoma vannamei Millar, 1977, an endemic ascidian from Brazil. As the new species does not fit Asterocheres in the strict sense, a new genus is erected to accommodate it. Setacheres gen. nov. is characterized by its possession of two distal setae on the third endopodal segment of P3, thus differing from the distal seta and spine pattern that is deemed as diagnostic of Asterocheres. A revision and comparison of Asterocheres´ species inquirendae revealed eight species sharing the same generic characteristics and were thus reallocated as members of the new genus. PMID:27395122

  1. Ascidian eggs block polyspermy by two independent mechanisms: one at the egg plasma membrane, the other involving the follicle cells.

    PubMed

    Lambert, C; Goudeau, H; Franchet, C; Lambert, G; Goudeau, M

    1997-09-01

    Many ascidians live in clumps and usually release sperm before the eggs. Consequently, eggs are often spawned into dense clouds of sperm. Because fertilization by more than a single sperm is lethal, ascidians have evolved at least two successive blocks to polyspermy: the rapid release of a glycosidase that inhibits sperm binding to the vitelline coat (VC) and a subsequent change in membrane potential that prevents supernumerary sperm-egg fusion. This paper shows that (1) these two blocks can be uncoupled by the use of suramin, and (2) most of the glycosidase appears to be from the follicle cells, which are accessory cells on the outside of the egg VC. Phallusia mammillata eggs initially bind numerous sperm but, after the glycosidase is released, only a few additional sperm bind. Intact eggs in 20 microM suramin release glycosidase, but the electrical response is inhibited; sperm swim actively and bind to the VC but fail to penetrate. Suramin treatment is completely reversible; intact eggs exhibit the electrical response an average of 11 minutes after the drug is washed out. Sperm must contact the follicle cells before passing through the VC; eggs with the VC removed and fertilized in the presence of 20 microM suramin show the electrical response 35% of the time, thus VC removal enhances sperm entry. Like the intact eggs, 100% of the naked eggs respond electrically to fertilization after the drug is washed out. Follicle cells that are isolated by calcium magnesium free seawater and then returned to complete seawater release N-acetylglucosaminidase activity in response to sperm. Thus, these eggs have two blocks to polyspermy that operate in sequence: an early first block resulting from enzymatic modification of the VC by N-acetylglucosaminidase released primarily from follicle cells and a second electrical block operating at the egg plasma membrane level and requiring sperm-egg fusion. PMID:9266770

  2. Anticancer effects of brominated indole alkaloid Eudistomin H from marine ascidian Eudistoma viride against cervical cancer cells (HeLa).

    PubMed

    Rajesh, Rajaian Pushpabai; Annappan, Murugan

    2015-01-01

    Marine invertebrates called ascidians are prolific producers of bioactive substances. The ascidian Eudistoma viride, distributed along the Southeast coast of India, was investigated for its in vitro cytotoxic activity against human cervical carcinoma (HeLa) cells by the MTT assay. The crude methanolic extract of E. viride, with an IC50 of 53 μg/ml, was dose-dependently cytotoxic. It was more potent at 100 μg/ml than cyclohexamide (1 μg/ml), reducing cell viability to 9.2%. Among nine fractions separated by chromatography, ECF-8 exhibited prominent cytoxic activity at 10 μg/ml. The HPLC fraction EHF-21 of ECF-8 was remarkably dose- and time-dependently cytotoxic, with 39.8% viable cells at 1 μg/ml compared to 51% in cyclohexamide-treated cells at the same concentration; the IC50 was 0.49 μg/ml. Hoechst staining of HeLa cells treated with EHF-21 at 0.5 μg/ml revealed apoptotic events such an cell shrinkage, membrane blebbing, chromatin condensation and formation of apoptotic bodies. Cell size and granularity study showed changes in light scatter, indicating the characteristic feature of cells dying by apoptosis. The cell-cycle analysis of HeLa cells treated with fraction EHF-21 at 1 μg/ml showed the marked arrest of cells in G0/G1, S and G2/M phases and an increase in the sub G0/G1 population indicated an increase in the apoptotic cell population. The statistical analysis of the sub-G1 region showed a dose-dependent induction of apoptosis. DNA fragmentation was also observed in HeLa cells treated with EHF-21. The active EHF-21 fraction, a brominated indole alkaloid Eudistomin H, led to apoptotic death of HeLa cells. PMID:25550562

  3. Neural induction suppresses early expression of the inward-rectifier K+ channel in the ascidian blastomere.

    PubMed Central

    Okamura, Y; Takahashi, K

    1993-01-01

    1. Early expression of ion channels following neural induction was examined in isolated, cleavage-arrested blastomeres from the ascidian embryo using a two-electrode voltage clamp. Currents were recorded from the isolated, cleavage-arrested blastomere, a4-2, after treatment with serine protease, subtilisin, which induces neural differentiation as consistently as cell contact. 2. The inward-rectifier K+ current increased at the late gastrula stage shortly after the sensitive period for neural induction both in the induced (protease-treated) and uninduced cells. Ca2+ channels, characteristic of epidermal-type differentiation, and delayed-rectifier K+ channels and differentiated-type Na+ channels, characteristic of neural-type differentiation appeared much later than the inward-rectifier K+ channels, at a time corresponding to the tail bud stage of the intact embryo. 3. When cells were treated with subtilisin during the critical period for neural induction, the increase in the inward-rectifier K+ current from the late gastrula stage to the neurula stage was about three times smaller (3.67 +/- 1.74 nA, mean +/- S.D., n = 14) than in untreated cells (11.25 +/- 3.10 nA, n = 26). The same changes in the inward-rectifier K+ channel were also observed in a4 2 blastomeres which were induced by cell contact with an A4-1 blastomere. However, when cells were treated with subtilisin after the critical period for neural induction, the amplitude of the inward-rectifier K+ current was the same as in untreated cells. Thus the expressed level of the inward-rectifier K+ channel was linked to the determination of neural or epidermal cell types. 4. There was no significant difference in the input capacitance of induced and uninduced cells, indicating that the difference in the amplitude of the inward-rectifier K+ currents derived from a difference in the channel density rather than a difference in cell surface area. 5. The expression of the inward-rectifier K+ channel at the late

  4. Excitation energy relaxation in a symbiotic cyanobacterium, Prochloron didemni, occurring in coral-reef ascidians, and in a free-living cyanobacterium, Prochlorothrix hollandica.

    PubMed

    Hamada, Fumiya; Yokono, Makio; Hirose, Euichi; Murakami, Akio; Akimoto, Seiji

    2012-11-01

    The marine cyanobacterium Prochloron is a unique photosynthetic organism that lives in obligate symbiosis with colonial ascidians. We compared Prochloron harbored in four different host species and cultured Prochlorothrix by means of spectroscopic measurements, including time-resolved fluorescence, to investigate host-induced differences in light-harvesting strategies between the cyanobacteria. The light-harvesting efficiency of photosystems including antenna Pcb, PS II-PS I connection, and pigment status, especially that of PS I Red Chls, were different among the four samples. We also discuss relationships between these observed characteristics and the light conditions, to which Prochloron cells are exposed, influenced by distribution pattern in the host colonies, presence or absence of tunic spicules, and microenvironments within the ascidians' habitat. PMID:22728755

  5. Complete mtDNA of Ciona intestinalis reveals extensive gene rearrangement and the presence of an atp8 and an extra trnM gene in ascidians.

    PubMed

    Gissi, Carmela; Iannelli, Fabio; Pesole, Graziano

    2004-04-01

    The complete mitochondrial genome (mtDNA) of the model organism Ciona intestinalis (Urochordata, Ascidiacea) has been amplified by long-PCR using specific primers designed on putative mitochondrial transcripts identified from publicly available mitochondrial-like expressed sequence tags. The C. intestinalis mtDNA encodes 39 genes: 2 rRNAs, 13 subunits of the respiratory complexes, including ATPase subunit 8 ( atp8), and 24 tRNAs, including 2 tRNA-Met with anticodons 5'-UAU-3'and 5'-CAU-3', respectively. All genes are transcribed from the same strand. This gene content seems to be a common feature of ascidian mtDNAs, as we have verified the presence of a previously undetected atp8 and of two trnM genes in the two other sequenced ascidian mtDNAs. Extensive gene rearrangement has been found in C. intestinalis with respect not only to the common Vertebrata/Cephalochordata/Hemichordata gene organization but also to other ascidian mtDNAs, including the cogeneric Ciona savignyi. Other features such as the absence of long noncoding regions, the shortness of rRNA genes, the low GC content (21.4%), and the absence of asymmetric base distribution between the two strands suggest that this genome is more similar to those of some protostomes than to deuterostomes. PMID:15114417

  6. Identification of eusynstyelamide B as a potent cell cycle inhibitor following the generation and screening of an ascidian-derived extract library using a real time cell analyzer.

    PubMed

    Liberio, Michelle S; Sadowski, Martin C; Nelson, Colleen C; Davis, Rohan A

    2014-10-01

    Ascidians are marine invertebrates that have been a source of numerous cytotoxic compounds. Of the first six marine-derived drugs that made anticancer clinical trials, three originated from ascidian specimens. In order to identify new anti-neoplastic compounds, an ascidian extract library (143 samples) was generated and screened in MDA-MB-231 breast cancer cells using a real-time cell analyzer (RTCA). This resulted in 143 time-dependent cell response profiles (TCRP), which are read-outs of changes to the growth rate, morphology, and adhesive characteristics of the cell culture. Twenty-one extracts affected the TCRP of MDA-MB-231 cells and were further investigated regarding toxicity and specificity, as well as their effects on cell morphology and cell cycle. The results of these studies were used to prioritize extracts for bioassay-guided fractionation, which led to the isolation of the previously identified marine natural product, eusynstyelamide B (1). This bis-indole alkaloid was shown to display an IC50 of 5 µM in MDA-MB-231 cells. Moreover, 1 caused a strong cell cycle arrest in G2/M and induced apoptosis after 72 h treatment, making this molecule an attractive candidate for further mechanism of action studies. PMID:25329705

  7. Photoadaptation and protection against active forms of oxygen in the symbiotic procaryote Prochloron sp. and its ascidian host

    SciTech Connect

    Lesser, M.P.; Stochaj, W.R. )

    1990-06-01

    Superoxide dismutase, ascorbate, peroxidase, and catalase activities were studied in the symbiotic photosynthetic procaryote Prochloron sp. and its ascidian host Lissoclinum patella. The protein-specific activities of these antioxidant enzymes in the Prochloron sp. and L. patella collected at different depths from the Great Barrier Reef, Australia, were directly proportional to irradiance, whereas the pigment concentrations in the Prochloron sp. were inversely proportional to irradiance. The presence of a cyanide-sensitive superoxide dismutase, presumably a Cu-An metalloprotein, in the Prochloron sp. extends the possible phylogenetic distribution of this protein. The concentration of UV-absorbing mycosporine-like amino acids in inversely proportional to irradiance in both the host and symbiont, suggesting that these compounds may not provide sufficient protection against UV radiation in high-irradiance environments. The significant differences in the specific activities of these antioxidant enzymes, cellular photosynthetic pigment concentrations, and UV-absorbing compounds from high- and low-irradiance habitats constitute an adaptive response to different photic environments. These photoadaptive responses are essential to prevent inhibition of photosynthesis by high fluxes of visible and UV radiation.

  8. Msxb is a core component of the genetic circuitry specifying the dorsal and ventral neurogenic midlines in the ascidian embryo.

    PubMed

    Roure, Agnès; Darras, Sébastien

    2016-01-01

    The tail ascidian larval peripheral nervous system is made up of epidermal sensory neurons distributed more or less regularly in ventral and dorsal midlines. Their formation occurs in two-steps: the ventral and dorsal midlines are induced as neurogenic territories by Fgf9/16/20 and Admp respectively. The Delta2/Notch interaction then controls the number of neurons that form. The genetic machinery acting between the inductive processes taking place before gastrulation and neuron specification at tailbud stages are largely unknown. The analysis of seven transcription factors expressed in the forming midlines revealed an unexpected complexity and dynamic of gene expression. Their systematic overexpression confirmed that these genes do not interact following a linear cascade of activation. However, the integration of our data revealed the distinct key roles of the two upstream factors Msxb and Nkx-C that are the earliest expressed genes and the only ones able to induce neurogenic midline and ESN formation. Our data suggest that Msxb would be the primary midline gene integrating inputs from the ventral and dorsal inducers and launching a pan-midline transcriptional program. Nkx-C would be involved in tail tip specification, in maintenance of the pan-midline network and in a posterior to anterior wave controlling differentiation. PMID:26592100

  9. A voltage-gated chloride channel in ascidian embryos modulated by both the cell cycle clock and cell volume.

    PubMed Central

    Villaz, M; Cinniger, J C; Moody, W J

    1995-01-01

    1. Eggs of the ascidian Boltenia villosa have an inwardly rectifying Cl- current whose amplitude varies by more than 10-fold during each cell cycle, the largest amplitude being at exit from M-phase. We examined whether this current was also sensitive to changes in cell volume. 2. Cell swelling, produced by direct inflation through a whole-cell recording pipette, greatly increased the amplitude of the Cl- current at all stages of the cell cycle in activated eggs. Swelling was much less effective in unfertilized eggs. 3. The increase in Cl- current amplitude continued for 10-20 min after an increase in diameter that was complete in 10 s, suggesting the involvement of a second messenger system in the response. 4. Treatment of unfertilized eggs with 6-dimethylaminopurine (DMAP), an inhibitor of cell cycle-dependent protein kinases, increased the amplitude of the Cl- current and its sensitivity to swelling to levels characteristic of fertilized eggs. 5. Osmotically produced swelling also increased Cl- current amplitude in unfertilized eggs. 6. We propose that dephosphorylation renders the Cl- channel functional, and that swelling or activation of the egg increases the sensitivity of the channel to dephosphorylation, perhaps by disrupting its links to the cytoskeleton. PMID:8576858

  10. Photoadaptation and Protection against Active Forms of Oxygen in the Symbiotic Procaryote Prochloron sp. and Its Ascidian Host

    PubMed Central

    Lesser, Michael P.; Stochaj, Wayne R.

    1990-01-01

    Superoxide dismutase, ascorbate peroxidase, and catalase activities were studied in the symbiotic photosynthetic procaryote Prochloron sp. and its ascidian host Lissoclinum patella. The protein-specific activities of these antioxidant enzymes in the Prochloron sp. and L. patella collected at different depths from the Great Barrier Reef, Australia, were directly proportional to irradiance, whereas the pigment concentrations in the Prochloron sp. were inversely proportional to irradiance. The presence of a cyanide-sensitive superoxide dismutase, presumably a Cu-Zn metalloprotein, in the Prochloron sp. extends the possible phylogenetic distribution of this protein. The concentration of UV-absorbing mycosporine-like amino acids is inversely proportional to irradiance in both the host and symbiont, suggesting that these compounds may not provide sufficient protection against UV radiation in high-irradiance environments. The significant differences in the specific activities of these antioxidant enzymes, cellular photosynthetic pigment concentrations, and UV-absorbing compounds from high- and low-irradiance habitats constitute an adaptive response to different photic environments. These photoadaptive responses are essential to prevent inhibition of photosynthesis by high fluxes of visible and UV radiation. PMID:16348202

  11. Toxicity assessment of the antifouling compound zinc pyrithione using early developmental stages of the ascidian Ciona intestinalis.

    PubMed

    Bellas, Juan

    2005-01-01

    This study investigated the toxicity of zinc pyrithione (Zpt) on the early stages of development of the ascidian Ciona intestinalis. Larval morphological abnormalities were studied after the exposure of C. intestinalis embryos at different stages of development. The median effective concentrations (EC50) ranged from 226-590 nM. The larval settlement stage was the most sensitive to Zpt. Toxic effects of Zpt on larval settlement were detected at 9 nM (EC10). The inhibition of C. intestinalis embryonic development was also used to study the loss of toxicity in Zpt solutions exposed to direct sunlight and laboratory UV light. The results showed that the toxicity of Zpt solutions decreased but did not disappear after 4 h exposure to direct sunlight (EC50 = 484 nM) or UV light (EC50 = 453 nM), compared to control Zpt solutions prepared in dark conditions. On the basis of the present data, predicted no effect concentrations of Zpt to C. intestinalis larvae are lower than predicted environmental concentrations of Zpt in certain polluted areas and therefore, may pose a risk to C. intestinalis populations. PMID:16522542

  12. Insulin-like genes in ascidians: findings in Ciona and hypotheses on the evolutionary origins of the pancreas

    PubMed Central

    Thompson, Jordan M.; Di Gregorio, Anna

    2014-01-01

    Insulin plays an extensively characterized role in the control of sugar metabolism, growth and homeostasis in a wide range of organisms. In vertebrate chordates, insulin is mainly produced by the beta cells of the endocrine pancreas, while in non-chordate animals insulin-producing cells are mainly found in the nervous system and/or scattered along the digestive tract. However, recent studies have indicated the notochord, the defining feature of the chordate phylum, as an additional site of expression of insulin-like peptides. Here we show that two of the three insulin-like genes identified in Ciona intestinalis, an invertebrate chordate with a dual life cycle, are first expressed in the developing notochord during embryogenesis and transition to distinct areas of the adult digestive tract after metamorphosis. In addition, we present data suggesting that the transcription factor Ciona Brachyury is involved in the control of notochord expression of at least one of these genes, Ciona insulin-like 2. Lastly, we review the information currently available on insulin-producing cells in ascidians and on pancreas-related transcription factors that might control their expression. PMID:25378051

  13. A one-dimensional model of PCP signaling: polarized cell behavior in the notochord of the ascidian Ciona

    PubMed Central

    Kourakis, Matthew J.; Reeves, Wendy; Newman-Smith, Erin; Maury, Benoit; Abdul-Wajid, Sarah; Smith, William C.

    2014-01-01

    Despite its importance in development and physiology the planar cell polarity (PCP) pathway remains one of the most enigmatic signaling mechanisms. The notochord of the ascidian Ciona provides a unique model for investigating the PCP pathway. Interestingly, the notochord appears to be the only embryonic structure in Ciona activating the PCP pathway. Moreover, the Ciona notochord as a single-file array of forty polarized cells is a uniquely tractable system for the study of polarization dynamics and the transmission of the PCP pathway. Here, we test models for propagation of a polarizing signal, interrogating temporal, spatial and signaling requirements. A simple cell-cell relay cascading through the entire length of the notochord is not supported; instead a more complex mechanism is revealed, with interactions influencing polarity between neighboring cells, but not distant ones. Mechanisms coordinating notochord-wide polarity remain elusive, but appear to entrain general (i.e., global) polarity even while local interactions remain important. However, this global polarizer does not appear to act as a localized, spatially-restricted determinant. Coordination of polarity along the long axis of the notochord requires the PCP pathway, a role we demonstrate is temporally distinct from this pathway’s earlier role in convergent extension and intercalation. We also reveal polarity in the notochord to be dynamic: a cell’s polarity state can be changed and then restored, underscoring the Ciona notochord’s amenability for in vivo studies of PCP. PMID:25173874

  14. Distal regeneration involves the age dependent activity of branchial sac stem cells in the ascidian Ciona intestinalis

    PubMed Central

    2014-01-01

    Abstract Tunicates have high capacities for regeneration but the underlying mechanisms and their relationship to life cycle progression are not well understood. Here we investigate the regeneration of distal structures in the ascidian tunicate Ciona intestinalis. Analysis of regenerative potential along the proximal−distal body axis indicated that distal organs, such as the siphons, their pigmented sensory organs, and the neural complex, could only be replaced from body fragments containing the branchial sac. Distal regeneration involves the formation of a blastema composed of cells that undergo cell proliferation prior to differentiation and cells that differentiate without cell proliferation. Both cell types originate in the branchial sac and appear in the blastema at different times after distal injury. Whereas the branchial sac stem cells are present in young animals, they are depleted in old animals that have lost their regeneration capacity. Thus Ciona adults contain a population of age‐related stem cells located in the branchial sac that are a source of precursors for distal body regeneration. PMID:25893097

  15. Biologically Active Acetylenic Amino Alcohol and N-Hydroxylated 1,2,3,4-Tetrahydro-β-carboline Constituents of the New Zealand Ascidian Pseudodistoma opacum.

    PubMed

    Wang, Jiayi; Pearce, A Norrie; Chan, Susanna T S; Taylor, Richard B; Page, Michael J; Valentin, Alexis; Bourguet-Kondracki, Marie-Lise; Dalton, James P; Wiles, Siouxsie; Copp, Brent R

    2016-03-25

    The first occurrence of an acetylenic 1-amino-2-alcohol, distaminolyne A (1), isolated from the New Zealand ascidian Pseudodistoma opacum, is reported. The isolation and structure elucidation of 1 and assignment of absolute configuration using the exciton coupled circular dichroism technique are described. In addition, a new N-9 hydroxy analogue (2) of the known P. opacum metabolite 7-bromohomotrypargine is also reported. Antimicrobial screening identified modest activity of 1 toward Escherichia coli, Staphylococcus aureus, and Mycobacterim tuberculosis, while 2 exhibited a moderate antimalarial activity (IC50 3.82 μM) toward a chloroquine-resistant strain (FcB1) of Plasmodium falciparum. PMID:26670413

  16. Stochasticity in space, persistence in time: genetic heterogeneity in harbour populations of the introduced ascidian Styela plicata

    PubMed Central

    Pineda, Mari-Carmen; Lorente, Beatriz; López-Legentil, Susanna; Palacín, Creu

    2016-01-01

    Spatio-temporal changes in genetic structure among populations provide crucial information on the dynamics of secondary spread for introduced marine species. However, temporal components have rarely been taken into consideration when studying the population genetics of non-indigenous species. This study analysed the genetic structure of Styela plicata, a solitary ascidian introduced in harbours and marinas of tropical and temperate waters, across spatial and temporal scales. A fragment of the mitochondrial gene Cytochrome Oxidase subunit I (COI) was sequenced from 395 individuals collected at 9 harbours along the NW Mediterranean coast and adjacent Atlantic waters (> 1,200 km range) at two time points 5 years apart (2009 and 2014). The levels of gene diversity were relatively low for all 9 locations in both years. Analyses of genetic differentiation and distribution of molecular variance revealed strong genetic structure, with significant differences among many populations, but no significant differences among years. A weak and marginally significant correlation between geographic distance and gene differentiation was found. Our results revealed spatial structure and temporal genetic homogeneity in S. plicata, suggesting a limited role of recurrent, vessel-mediated transport of organisms among small to medium-size harbours. Our study area is representative of many highly urbanized coasts with dense harbours. In these environments, the episodic chance arrival of colonisers appears to determine the genetic structure of harbour populations and the genetic composition of these early colonising individuals persists in the respective harbours, at least over moderate time frames (five years) that encompass ca. 20 generations of S. plicata. PMID:27366653

  17. Increased Inter-Colony Fusion Rates Are Associated with Reduced COI Haplotype Diversity in an Invasive Colonial Ascidian Didemnum vexillum

    PubMed Central

    Smith, Kirsty F.; Stefaniak, Lauren; Saito, Yasunori; Gemmill, Chrissen E. C.; Cary, S. Craig; Fidler, Andrew E.

    2012-01-01

    Considerable progress in our understanding of the population genetic changes associated with biological invasions has been made over the past decade. Using selectively neutral loci, it has been established that reductions in genetic diversity, reflecting founder effects, have occurred during the establishment of some invasive populations. However, some colonial organisms may actually gain an ecological advantage from reduced genetic diversity because of the associated reduction in inter-colony conflict. Here we report population genetic analyses, along with colony fusion experiments, for a highly invasive colonial ascidian, Didemnum vexillum. Analyses based on mitochondrial cytochrome oxidase I (COI) partial coding sequences revealed two distinct D. vexillum clades. One COI clade appears to be restricted to the probable native region (i.e., north-west Pacific Ocean), while the other clade is present in widely dispersed temperate coastal waters around the world. This clade structure was supported by 18S ribosomal DNA (rDNA) sequence data, which revealed a one base-pair difference between the two clades. Recently established populations of D. vexillum in New Zealand displayed greatly reduced COI genetic diversity when compared with D. vexillum in Japan. In association with this reduction in genetic diversity was a significantly higher inter-colony fusion rate between randomly paired New Zealand D. vexillum colonies (80%, standard deviation ±18%) when compared with colonies found in Japan (27%, standard deviation ±15%). The results of this study add to growing evidence that for colonial organisms reductions in population level genetic diversity may alter colony interaction dynamics and enhance the invasive potential of newly colonizing species. PMID:22303442

  18. Immunotoxicity in ascidians: antifouling compounds alternative to organotins: III--the case of copper(I) and Irgarol 1051.

    PubMed

    Cima, Francesca; Ballarin, Loriano

    2012-09-01

    After the widespread ban of TBT, due to its severe impact on coastal biocoenoses, mainly related to its immunosuppressive effects on both invertebrates and vertebrates, alternative biocides such as Cu(I) salts and the triazine Irgarol 1051, the latter previously used in agriculture as a herbicide, have been massively introduced in combined formulations for antifouling paints against a wide spectrum of fouling organisms. Using short-term (60 min) haemocyte cultures of the colonial ascidian Botryllus schlosseri exposed to various sublethal concentrations of copper(I) chloride (LC(50)=281 μM, i.e., 17.8 mg Cu L(-1)) and Irgarol 1051 (LC(50)>500 μM, i.e., >127 mg L(-1)), we evaluated their immunotoxic effects through a series of cytochemical assays previously used for organotin compounds. Both compounds can induce dose-dependent immunosuppression, acting on different cellular targets and altering many activities of immunocytes but, unlike TBT, did not have significant effects on cell morphology. Generally, Cu(I) appeared to be more toxic than Irgarol 1051: it significantly (p<0.05) inhibited yeast phagocytosis at 0.1 μM (∼10 μg L(-1)), and affected calcium homeostasis and mitochondrial cytochrome-c oxidase activity at 0.01 μM (∼1 μg L(-1)). Both substances were able to change membrane permeability, induce apoptosis from concentrations of 0.1 μM (∼10 μg L(-1)) and 200 μM (∼50 mg L(-1)) for Cu(I) and Irgarol 1051, respectively, and alter the activity of hydrolases. Both Cu(I) and Irgarol 1051 inhibited the activity of phenoloxidase, but did not show any interactive effect when co-present in the exposure medium, suggesting different mechanisms of action. PMID:22542202

  19. Bigger is not always better: offspring size does not predict growth or survival for seven ascidian species.

    PubMed

    Jacobs, Molly W; Sherrard, Kristin M

    2010-12-01

    The presumed trade-off between offspring size and quality predicted by life history theory is often invoked to explain the wide range of propagule sizes observed in animals and plants. This trade-off is broadly supported by intraspecific studies but has been difficult to test in an interspecific context, particularly in animals. We tested the fitness consequences of offspring size both intra- and interspecifically for seven species of ascidians (sessile, suspension-feeding, marine invertebrates) whose offspring volumes varied over three orders of magnitude. We measured two major components of fitness, juvenile growth rates and survival, in laboratory and field experiments encompassing several food conditions. Contrary to the predictions of life history theory, larger offspring size did not result in higher rates of growth or survival, and large offspring did not perform better under nutritional stress, either intraspecifically or interspecifically. In fact, two of the four species with small offspring grew rapidly enough to catch up in size to the species with large offspring in as little as eight weeks, under wild-type food conditions. Trade-offs between growth potential and defense may overwhelm and obscure any trade-offs between offspring size and survival or growth rate. While large initial size may still confer a competitive advantage, we failed to detect any consequences of interspecific variation in initial size. This implies that larger offspring in these species, far from being inherently superior in growth or survival, require compensation in other aspects of life history if reproductive effort is to be efficient. Our results suggest that the importance of initial offspring size is context dependent and often overestimated relative to other life history traits. PMID:21302831

  20. Stochasticity in space, persistence in time: genetic heterogeneity in harbour populations of the introduced ascidian Styela plicata.

    PubMed

    Pineda, Mari-Carmen; Lorente, Beatriz; López-Legentil, Susanna; Palacín, Creu; Turon, Xavier

    2016-01-01

    Spatio-temporal changes in genetic structure among populations provide crucial information on the dynamics of secondary spread for introduced marine species. However, temporal components have rarely been taken into consideration when studying the population genetics of non-indigenous species. This study analysed the genetic structure of Styela plicata, a solitary ascidian introduced in harbours and marinas of tropical and temperate waters, across spatial and temporal scales. A fragment of the mitochondrial gene Cytochrome Oxidase subunit I (COI) was sequenced from 395 individuals collected at 9 harbours along the NW Mediterranean coast and adjacent Atlantic waters (> 1,200 km range) at two time points 5 years apart (2009 and 2014). The levels of gene diversity were relatively low for all 9 locations in both years. Analyses of genetic differentiation and distribution of molecular variance revealed strong genetic structure, with significant differences among many populations, but no significant differences among years. A weak and marginally significant correlation between geographic distance and gene differentiation was found. Our results revealed spatial structure and temporal genetic homogeneity in S. plicata, suggesting a limited role of recurrent, vessel-mediated transport of organisms among small to medium-size harbours. Our study area is representative of many highly urbanized coasts with dense harbours. In these environments, the episodic chance arrival of colonisers appears to determine the genetic structure of harbour populations and the genetic composition of these early colonising individuals persists in the respective harbours, at least over moderate time frames (five years) that encompass ca. 20 generations of S. plicata. PMID:27366653

  1. Dynamic change in the expression of developmental genes in the ascidian central nervous system: revisit to the tripartite model and the origin of the midbrain-hindbrain boundary region.

    PubMed

    Ikuta, Tetsuro; Saiga, Hidetoshi

    2007-12-15

    Comparative studies on expression patterns of developmental genes along the anterior-posterior axis of the embryonic central nervous system (CNS) between vertebrates and ascidians led to the notion of "tripartite organization," a common ground plan of the CNS, consisting of the anterior, central and posterior regions expressing Otx, Pax2/5/8 and Hox genes, respectively. In ascidians, however, descriptions and interpretations about expression of the developmental genes regarded as region specific have become not necessarily consistent. To address this issue, we examined detailed expression of key developmental genes for the ascidian CNS, including Otx, Pax2/5/8a, En, Fgf8/17/18, Dmbx, Lhx3 and Hox genes, in the CNS around the junction of the trunk and tail of three different tailbud-stage embryos of Ciona intestinalis, employing double-fluorescence in situ hybridization, followed by staining with DAPI to precisely locate expressing cells for each gene. Based on these observations, we have constructed detailed gene expression maps of the region at the tailbud stages. Our analysis shows that expression of several genes regarded as markers for specific domains in the ascidian CNS changes dynamically within a relatively short period. This motivates us to revisit to the tripartite ground plan and the origin of the midbrain-hindbrain boundary (MHB) region. PMID:17996862

  2. Co-expression of Foxa.a, Foxd and Fgf9/16/20 defines a transient mesendoderm regulatory state in ascidian embryos

    PubMed Central

    Hudson, Clare; Sirour, Cathy; Yasuo, Hitoyoshi

    2016-01-01

    In many bilaterian embryos, nuclear β-catenin (nβ-catenin) promotes mesendoderm over ectoderm lineages. Although this is likely to represent an evolutionary ancient developmental process, the regulatory architecture of nβ-catenin-induced mesendoderm remains elusive in the majority of animals. Here, we show that, in ascidian embryos, three nβ-catenin transcriptional targets, Foxa.a, Foxd and Fgf9/16/20, are each required for the correct initiation of both the mesoderm and endoderm gene regulatory networks. Conversely, these three factors are sufficient, in combination, to produce a mesendoderm ground state that can be further programmed into mesoderm or endoderm lineages. Importantly, we show that the combinatorial activity of these three factors is sufficient to reprogramme developing ectoderm cells to mesendoderm. We conclude that in ascidian embryos, the transient mesendoderm regulatory state is defined by co-expression of Foxa.a, Foxd and Fgf9/16/20. DOI: http://dx.doi.org/10.7554/eLife.14692.001 PMID:27351101

  3. The ascidian-associated mysid Corellamysis eltanina gen.nov., sp.nov. (Mysida, Mysidae, Heteromysinae): a new symbiotic relationship from the Southern Ocean.

    PubMed

    Vicente, Carlos San; Monniot, Françoise

    2014-01-01

    A new mysid species representing a new genus is described based on specimens collected in the 1968 cruise of the U.S. Navy Ship Eltanin from the Macquarie Island region (Southern Ocean). The new mysid, Corellamysis eltanina, is characterized by the globular eyes lacking definite eyestalks, the seven and eighth thoracic endopods specialized as gnathopods forming a strong subchela, and by the armature and shape of the uropod endopod and telson. Corellamysis eltanina lives only in the branchial sacs of the ascidian Corella brewinae suggesting an obligate endocommensal symbiotic association. Therefore, this is the first known report of a mysid living symbiotically with a benthic tunicate, as well as the first report of a mysid symbiosis from the Southern Ocean. The distribution and habitats of known symbiont mysids are reviewed. An update of identification key to world genera and subgenera of Heteromysinae is suggested.  PMID:24871839

  4. The sexual and mating system of the shrimp Odontonia katoi (Palaemonidae, Pontoniinae), a symbiotic guest of the ascidian Polycarpa aurata in the Coral Triangle.

    PubMed

    Baeza, J Antonio; Hemphill, Carrie A; Ritson-Williams, Raphael

    2015-01-01

    Theory predicts that monogamy is adaptive in symbiotic crustaceans inhabiting relatively small and morphologically simple hosts in tropical environments where predation risk away from hosts is high. We tested this prediction in the shrimp Odontonia katoi, which inhabits the atrial chamber of the ascidian Polycarpa aurata in the Coral Triangle. Preliminary observations in O. katoi indicated that males were smaller than females, which is suggestive of sex change (protandry) in some symbiotic organisms. Thus, we first investigated the sexual system of O. katoi to determine if this shrimp was sequentially hermaphroditic. Morphological identification and size frequency distributions indicated that the population comprised males that, on average, were smaller than females. Gonad dissections demonstrated the absence of transitional individuals. Thus, O. katoi is a gonochoric species with reverse sexual dimorphism. The population distribution of O. katoi in its ascidian host did not differ significantly from a random distribution and shrimps inhabiting the same host individual as pairs were found with a frequency similar to that expected by chance alone. This is in contrast to that reported for other socially monogamous crustaceans in which pairs of heterosexual conspecifics are found in host individuals more frequently than expected by chance alone. Thus, the available information argues against monogamy in O. katoi. Furthermore, that a high frequency of solitary females were found brooding embryos and that the sex ratio was skewed toward females suggests that males might be roaming among hosts in search of receptive females in O. katoi. Symbiotic crustaceans can be used as a model system to understand the adaptive value of sexual and mating systems in marine invertebrates. PMID:25799577

  5. Fine- and regional-scale genetic structure of the exotic ascidian Styela clava (Tunicata) in southwest England, 50 years after its introduction.

    PubMed

    Dupont, L; Viard, F; Dowell, M J; Wood, C; Bishop, J D D

    2009-02-01

    Styela clava, an ascidian native to the northwest Pacific, was first recorded in the Atlantic at Plymouth, southwest England, in 1953. It now ranges in the northeast Atlantic from Portugal to northern Denmark, and has colonized the east coast of North America. Within the region of first introduction, we aimed to characterize current genetic diversity in the species, elucidate the respective roles of human-aided vs. natural dispersal, and assess the extent of larval dispersal by looking for genetic differentiation at very small scales. Eight sites, mostly marinas, were studied along c. 200 km of coast in southwest England encompassing Plymouth. Five microsatellite loci were genotyped in 303 individuals to analyse gene flow at regional (among sites) and fine (within sites) scales. F-statistics and assignment tests were used to investigate regional genetic structure. At the fine scale, deviation from mutation-drift equilibrium was tested, and isolation by distance and genetic clustering analyses were undertaken. Significant genetic differentiation existed between sites, unrelated to geographical separation; migration between geographically distant marinas was inferred, highlighting the likely importance of human-mediated dispersal in range expansion and occupancy by S. clava. Fine-scale population structure was present within at least four sites, which may be explained by the limited dispersal ability of this ascidian and recruitment from differentiated pools of larvae. Populations in enclosed marinas had higher self-recruitment rates than those in open sites. Some marinas might therefore function as reservoirs of propagules for subsequent spread, whereas others might be sinks for migrants. PMID:19161467

  6. The Sexual and Mating System of the Shrimp Odontonia katoi (Palaemonidae, Pontoniinae), a Symbiotic Guest of the Ascidian Polycarpa aurata in the Coral Triangle

    PubMed Central

    Baeza, J. Antonio; Hemphill, Carrie A.; Ritson-Williams, Raphael

    2015-01-01

    Theory predicts that monogamy is adaptive in symbiotic crustaceans inhabiting relatively small and morphologically simple hosts in tropical environments where predation risk away from hosts is high. We tested this prediction in the shrimp Odontonia katoi, which inhabits the atrial chamber of the ascidian Polycarpa aurata in the Coral Triangle. Preliminary observations in O. katoi indicated that males were smaller than females, which is suggestive of sex change (protandry) in some symbiotic organisms. Thus, we first investigated the sexual system of O. katoi to determine if this shrimp was sequentially hermaphroditic. Morphological identification and size frequency distributions indicated that the population comprised males that, on average, were smaller than females. Gonad dissections demonstrated the absence of transitional individuals. Thus, O. katoi is a gonochoric species with reverse sexual dimorphism. The population distribution of O. katoi in its ascidian host did not differ significantly from a random distribution and shrimps inhabiting the same host individual as pairs were found with a frequency similar to that expected by chance alone. This is in contrast to that reported for other socially monogamous crustaceans in which pairs of heterosexual conspecifics are found in host individuals more frequently than expected by chance alone. Thus, the available information argues against monogamy in O. katoi. Furthermore, that a high frequency of solitary females were found brooding embryos and that the sex ratio was skewed toward females suggests that males might be roaming among hosts in search of receptive females in O. katoi. Symbiotic crustaceans can be used as a model system to understand the adaptive value of sexual and mating systems in marine invertebrates. PMID:25799577

  7. A Boolean Function for Neural Induction Reveals a Critical Role of Direct Intercellular Interactions in Patterning the Ectoderm of the Ascidian Embryo.

    PubMed

    Ohta, Naoyuki; Waki, Kana; Mochizuki, Atsushi; Satou, Yutaka

    2015-12-01

    A complex system of multiple signaling molecules often produce differential gene expression patterns in animal embryos. In the ascidian embryo, four signaling ligands, Ephrin-A.d (Efna.d), Fgf9/16/20, Admp, and Gdf1/3-r, coordinately induce Otx expression in the neural lineage at the 32-cell stage. However, it has not been determined whether differential inputs of all of these signaling pathways are really necessary. It is possible that differential activation of one of these signaling pathways is sufficient and the remaining signaling pathways are activated in all cells at similar levels. To address this question, we developed a parameter-free method for determining a Boolean function for Otx expression in the present study. We treated activities of signaling pathways as Boolean values, and we also took all possible patterns of signaling gradients into consideration. We successfully determined a Boolean function that explains Otx expression in the animal hemisphere of wild-type and morphant embryos at the 32-cell stage. This Boolean function was not inconsistent with three sensing patterns, which represented whether or not individual cells received sufficient amounts of the signaling molecules. These sensing patterns all indicated that differential expression of Otx in the neural lineage is primarily determined by Efna.d, but not by differential inputs of Fgf9/16/20, Admp, and Gdf1/3-r signaling. To confirm this hypothesis experimentally, we simultaneously knocked-down Admp, Gdf1/3-r, and Fgf9/16/20, and treated this triple morphant with recombinant bFGF and BMP4 proteins, which mimic Fgf9/16/20 and Admp/Gdf1/3-r activity, respectively. Although no differential inputs of Admp, Gdf1/3-r and Fgf9/16/20 signaling were expected under this experimental condition, Otx was expressed specifically in the neural lineage. Thus, direct cell-cell interactions through Efna.d play a critical role in patterning the ectoderm of the early ascidian embryo. PMID:26714026

  8. A Boolean Function for Neural Induction Reveals a Critical Role of Direct Intercellular Interactions in Patterning the Ectoderm of the Ascidian Embryo

    PubMed Central

    Mochizuki, Atsushi; Satou, Yutaka

    2015-01-01

    A complex system of multiple signaling molecules often produce differential gene expression patterns in animal embryos. In the ascidian embryo, four signaling ligands, Ephrin-A.d (Efna.d), Fgf9/16/20, Admp, and Gdf1/3-r, coordinately induce Otx expression in the neural lineage at the 32-cell stage. However, it has not been determined whether differential inputs of all of these signaling pathways are really necessary. It is possible that differential activation of one of these signaling pathways is sufficient and the remaining signaling pathways are activated in all cells at similar levels. To address this question, we developed a parameter-free method for determining a Boolean function for Otx expression in the present study. We treated activities of signaling pathways as Boolean values, and we also took all possible patterns of signaling gradients into consideration. We successfully determined a Boolean function that explains Otx expression in the animal hemisphere of wild-type and morphant embryos at the 32-cell stage. This Boolean function was not inconsistent with three sensing patterns, which represented whether or not individual cells received sufficient amounts of the signaling molecules. These sensing patterns all indicated that differential expression of Otx in the neural lineage is primarily determined by Efna.d, but not by differential inputs of Fgf9/16/20, Admp, and Gdf1/3-r signaling. To confirm this hypothesis experimentally, we simultaneously knocked-down Admp, Gdf1/3-r, and Fgf9/16/20, and treated this triple morphant with recombinant bFGF and BMP4 proteins, which mimic Fgf9/16/20 and Admp/Gdf1/3-r activity, respectively. Although no differential inputs of Admp, Gdf1/3-r and Fgf9/16/20 signaling were expected under this experimental condition, Otx was expressed specifically in the neural lineage. Thus, direct cell–cell interactions through Efna.d play a critical role in patterning the ectoderm of the early ascidian embryo. PMID:26714026

  9. Nitric Oxide Affects ERK Signaling through Down-Regulation of MAP Kinase Phosphatase Levels during Larval Development of the Ascidian Ciona intestinalis

    PubMed Central

    Palumbo, Anna

    2014-01-01

    In the ascidian Ciona intestinalis larval development and metamorphosis require a complex interplay of events, including nitric oxide (NO) production, MAP kinases (ERK, JNK) and caspase-3 activation. We have previously shown that NO levels affect the rate of metamorphosis, regulate caspase activity and promote an oxidative stress pathway, resulting in protein nitration. Here, we report that NO down-regulates MAP kinase phosphatases (mkps) expression affecting positively ERK signaling. By pharmacological approach, we observed that the reduction of endogenous NO levels caused a decrease of ERK phosphorylation, whereas increasing levels of NO induced ERK activation. We have also identified the ERK gene network affected by NO, including mpk1, mpk3 and some key developmental genes by quantitative gene expression analysis. We demonstrate that NO induces an ERK-independent down-regulation of mkp1 and mkp3, responsible for maintaining the ERK phosphorylation levels necessary for transcription of key metamorphic genes, such as the hormone receptor rev-erb and the van willebrand protein vwa1c. These results add new insights into the role played by NO during larval development and metamorphosis in Ciona, highlighting the cross-talk between different signaling pathways. PMID:25058405

  10. Evaluation of Cancer Preventive Activity and Structure-Activity Relationships of 3-Demethylubiquinone Q2, Isolated from the Ascidian Aplidium glabrum, and its Synthetic Analogues

    PubMed Central

    Fedorov, Sergey N.; Radchenko, Oleg S.; Shubina, Larisa K.; Balaneva, Nadezhda N.; Bode, Ann M.; Stonik, Valentin A.; Dong, Zigang

    2006-01-01

    Purpose 3-Demethylubiquinone Q2 (1) was isolated from the ascidian Aplidium glabrum. The cancer preventive properties and the structure-activity relationship for 3-demethylubiquinone Q2 (1) and 12 of its synthetic analogues (3–14) are reported. Methods Compounds 3–14, having one or several di- or triprenyl substitutions and quinone moieties with methoxyls in different positions, were synthesized. The cancer preventive properties of compounds 1 and 3–14 were tested in JB6 Cl41 mouse skin cells, using a variety of assessments, including the MTS assay, flow cytometry, and soft agar assay. Statistical nonparametric methods were used to confirm statistical significance. Results All quinones tested were shown to inhibit JB6 Cl41 cell transformation, to induce apoptosis, AP-1 and NF-κB activity, and to inhibit p53 activity. The most promising effects were indicated for compounds containing two isoprene units in a side chain and a methoxyl group at the para-position to a polyprenyl substitution. Conclusions Quinones 1 and 3–14 demonstrated cancer preventive activity in JB6 Cl41 cells, which may be attributed to the induction of p53-independent apoptosis. These activities depended on the length of side chains and on the positions of the methoxyl groups in the quinone part of the molecule. PMID:16320003

  11. The diatom-derived aldehyde decadienal affects life cycle transition in the ascidian Ciona intestinalis through nitric oxide/ERK signalling

    PubMed Central

    Castellano, Immacolata; Ercolesi, Elena; Romano, Giovanna; Ianora, Adrianna; Palumbo, Anna

    2015-01-01

    Polyunsaturated aldehydes (PUAs) are fatty-acid-derived metabolites produced by some microalgae, including different diatom species. PUAs are mainly produced as a wound-activated defence mechanism against microalgal predators or released from senescent cells at the end of a bloom. PUAs, including 2,4-trans-decadienal (DD), induce deleterious effects on embryonic and larval development of several planktonic and benthic organisms. Here, we report on the effects of DD on larval development and metamorphosis of the ascidian Ciona intestinalis. Ciona larval development is regulated by the cross-talking of different molecular events, including nitric oxide (NO) production, ERK activation and caspase 3-dependent apoptosis. We report that treatment with DD at the competence larval stage results in a delay in metamorphosis. DD affects redox balance by reducing total glutathione and NO levels. By biochemical and quantitative gene expression analysis, we identify the NO-signalling network affected by DD, including the upregulation of ERK phosphatase mkp1 and consequent reduction of ERK phosphorylation, with final changes in the expression of downstream ERK target genes. Overall, these results give new insights into the molecular pathways induced in marine organisms after exposure to PUAs during larval development, demonstrating that this aldehyde affects key checkpoints of larval transition from the vegetative to the reproductive life stage. PMID:25788553

  12. First in situ observations of the deep-sea carnivorous ascidian Dicopia antirrhinum Monniot C., 1972 in the Western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Mecho, A.; Aguzzi, J.; Company, J. B.; Canals, M.; Lastras, G.; Turon, X.

    2014-01-01

    Dicopia antirrhinum C. Monniot, 1972 is a rare species of deep-sea ascidian belonging to the Family Octacnemidae, reported at depths of 1000-2500 m in European Atlantic waters. Adult individuals have never been reported before in the Mediterranean Sea, where only seven juvenile specimens were found in 1975 at 500 m water depth in the Central basin (Malta). The affinities of these specimens with D. antirrhinum were noted, but lack of some typical characters of the species in juveniles prevented a definite taxonomical identification. No other member of the Octacnemidae has ever been found in the Mediterranean. In this study we describe the sampling of an adult specimen of D. antirrhinum at around 1100 m water depth on the flank of the La Fonera (Palamós) canyon, Northwestern Mediterranean, confirming their presence in the Mediterranean Sea. We also observed 5 individuals of this species on their natural habitat with a Remotely Operated Vehicle (ROV). Our results highlight the potential occurrence of Octacnemidae, the presence of which has been largely overlooked, in several deep-sea canyon areas within the Western Mediterranean basin. These observations are important because they indicate the need for increased sampling effort with new technologies, such as ROVs, in ecologically relevant habitats such as canyons, in order to obtain a more accurate picture of deep-sea biodiversity in the Mediterranean Sea.

  13. A pipeline for the systematic identification of non-redundant full-ORF cDNAs for polymorphic and evolutionary divergent genomes: Application to the ascidian Ciona intestinalis.

    PubMed

    Gilchrist, Michael J; Sobral, Daniel; Khoueiry, Pierre; Daian, Fabrice; Laporte, Batiste; Patrushev, Ilya; Matsumoto, Jun; Dewar, Ken; Hastings, Kenneth E M; Satou, Yutaka; Lemaire, Patrick; Rothbächer, Ute

    2015-08-15

    Genome-wide resources, such as collections of cDNA clones encoding for complete proteins (full-ORF clones), are crucial tools for studying the evolution of gene function and genetic interactions. Non-model organisms, in particular marine organisms, provide a rich source of functional diversity. Marine organism genomes are, however, frequently highly polymorphic and encode proteins that diverge significantly from those of well-annotated model genomes. The construction of full-ORF clone collections from non-model organisms is hindered by the difficulty of predicting accurately the N-terminal ends of proteins, and distinguishing recent paralogs from highly polymorphic alleles. We report a computational strategy that overcomes these difficulties, and allows for accurate gene level clustering of transcript data followed by the automated identification of full-ORFs with correct 5'- and 3'-ends. It is robust to polymorphism, includes paralog calling and does not require evolutionary proximity to well annotated model organisms. We developed this pipeline for the ascidian Ciona intestinalis, a highly polymorphic member of the divergent sister group of the vertebrates, emerging as a powerful model organism to study chordate gene function, Gene Regulatory Networks and molecular mechanisms underlying human pathologies. Using this pipeline we have generated the first full-ORF collection for a highly polymorphic marine invertebrate. It contains 19,163 full-ORF cDNA clones covering 60% of Ciona coding genes, and full-ORF orthologs for approximately half of curated human disease-associated genes. PMID:26025923

  14. A pipeline for the systematic identification of non-redundant full-ORF cDNAs for polymorphic and evolutionary divergent genomes: Application to the ascidian Ciona intestinalis

    PubMed Central

    Gilchrist, Michael J.; Sobral, Daniel; Khoueiry, Pierre; Daian, Fabrice; Laporte, Batiste; Patrushev, Ilya; Matsumoto, Jun; Dewar, Ken; Hastings, Kenneth E.M.; Satou, Yutaka; Lemaire, Patrick; Rothbächer, Ute

    2015-01-01

    Genome-wide resources, such as collections of cDNA clones encoding for complete proteins (full-ORF clones), are crucial tools for studying the evolution of gene function and genetic interactions. Non-model organisms, in particular marine organisms, provide a rich source of functional diversity. Marine organism genomes are, however, frequently highly polymorphic and encode proteins that diverge significantly from those of well-annotated model genomes. The construction of full-ORF clone collections from non-model organisms is hindered by the difficulty of predicting accurately the N-terminal ends of proteins, and distinguishing recent paralogs from highly polymorphic alleles. We report a computational strategy that overcomes these difficulties, and allows for accurate gene level clustering of transcript data followed by the automated identification of full-ORFs with correct 5′- and 3′-ends. It is robust to polymorphism, includes paralog calling and does not require evolutionary proximity to well annotated model organisms. We developed this pipeline for the ascidian Ciona intestinalis, a highly polymorphic member of the divergent sister group of the vertebrates, emerging as a powerful model organism to study chordate gene function, Gene Regulatory Networks and molecular mechanisms underlying human pathologies. Using this pipeline we have generated the first full-ORF collection for a highly polymorphic marine invertebrate. It contains 19,163 full-ORF cDNA clones covering 60% of Ciona coding genes, and full-ORF orthologs for approximately half of curated human disease-associated genes. PMID:26025923

  15. The colonial ascidian Didemnum sp. A: current distribution, basic biology and potential threat to marine communities of the northeast and west coasts of North America

    USGS Publications Warehouse

    Bullard, S.G.; Lambert, G.; Carman, M.R.; Byrnes, J.; Whitlatch, R.B.; Ruiz, G.; Miller, R.J.; Harris, L.; Valentine, P.C.; Collie, J.S.; Pederson, J.; McNaught, D.C.; Cohen, A.N.; Asch, R.G.; Dijkstra, J.; Heinonen, K.

    2007-01-01

    Didemnum sp. A is a colonial ascidian with rapidly expanding populations on the east and west coasts of North America. The origin of Didemum sp. A is unknown. Populations were first observed on the northeast coast of the U.S. in the late 1980s and on the west coast during the 1990s. It is currently undergoing a massive population explosion and is now a dominant member of many subtidal communities on both coasts. To determine Didemnum sp. A's current distribution, we conducted surveys from Maine to Virginia on the east coast and from British Columbia to southern California on the west coast of the U.S. between 1998 and 2005. In nearshore locations Didemnum sp. A currently ranges from Eastport, Maine to Shinnecock Bay, New York on the east coast. On the west coast it has been recorded from Humboldt Bay to Port San Luis in California, several sites in Puget Sound, Washington, including a heavily fouled mussel culture facility, and several sites in southwestern British Columbia on and adjacent to oyster and mussel farms. The species also occurs at deeper subtidal sites (up to 81 m) off New England, including Georges, Stellwagen and Tillies Banks. On Georges Bank numerous sites within a 230 km2 area are 50–90% covered by Didemnum sp. A; large colonies cement the pebble gravel into nearly solid mats that may smother infaunal organisms. These observations suggest that Didemnum sp. A has the potential to alter marine communities and affect economically important activities such as fishing and aquaculture.

  16. Reference gene selection for quantitative gene expression studies during biological invasions: A test on multiple genes and tissues in a model ascidian Ciona savignyi.

    PubMed

    Huang, Xuena; Gao, Yangchun; Jiang, Bei; Zhou, Zunchun; Zhan, Aibin

    2016-01-15

    As invasive species have successfully colonized a wide range of dramatically different local environments, they offer a good opportunity to study interactions between species and rapidly changing environments. Gene expression represents one of the primary and crucial mechanisms for rapid adaptation to local environments. Here, we aim to select reference genes for quantitative gene expression analysis based on quantitative Real-Time PCR (qRT-PCR) for a model invasive ascidian, Ciona savignyi. We analyzed the stability of ten candidate reference genes in three tissues (siphon, pharynx and intestine) under two key environmental stresses (temperature and salinity) in the marine realm based on three programs (geNorm, NormFinder and delta Ct method). Our results demonstrated only minor difference for stability rankings among the three methods. The use of different single reference gene might influence the data interpretation, while multiple reference genes could minimize possible errors. Therefore, reference gene combinations were recommended for different tissues - the optimal reference gene combination for siphon was RPS15 and RPL17 under temperature stress, and RPL17, UBQ and TubA under salinity treatment; for pharynx, TubB, TubA and RPL17 were the most stable genes under temperature stress, while TubB, TubA and UBQ were the best under salinity stress; for intestine, UBQ, RPS15 and RPL17 were the most reliable reference genes under both treatments. Our results suggest that the necessity of selection and test of reference genes for different tissues under varying environmental stresses. The results obtained here are expected to reveal mechanisms of gene expression-mediated invasion success using C. savignyi as a model species. PMID:26428313

  17. Evolution of the chordate regeneration blastema: Differential gene expression and conserved role of notch signaling during siphon regeneration in the ascidian Ciona.

    PubMed

    Hamada, Mayuko; Goricki, Spela; Byerly, Mardi S; Satoh, Noriyuki; Jeffery, William R

    2015-09-15

    The regeneration of the oral siphon (OS) and other distal structures in the ascidian Ciona intestinalis occurs by epimorphosis involving the formation of a blastema of proliferating cells. Despite the longstanding use of Ciona as a model in molecular developmental biology, regeneration in this system has not been previously explored by molecular analysis. Here we have employed microarray analysis and quantitative real time RT-PCR to identify genes with differential expression profiles during OS regeneration. The majority of differentially expressed genes were downregulated during OS regeneration, suggesting roles in normal growth and homeostasis. However, a subset of differentially expressed genes was upregulated in the regenerating OS, suggesting functional roles during regeneration. Among the upregulated genes were key members of the Notch signaling pathway, including those encoding the delta and jagged ligands, two fringe modulators, and to a lesser extent the notch receptor. In situ hybridization showed a complementary pattern of delta1 and notch gene expression in the blastema of the regenerating OS. Chemical inhibition of the Notch signaling pathway reduced the levels of cell proliferation in the branchial sac, a stem cell niche that contributes progenitor cells to the regenerating OS, and in the OS regeneration blastema, where siphon muscle fibers eventually re-differentiate. Chemical inhibition also prevented the replacement of oral siphon pigment organs, sensory receptors rimming the entrance of the OS, and siphon muscle fibers, but had no effects on the formation of the wound epidermis. Since Notch signaling is involved in the maintenance of proliferative activity in both the Ciona and vertebrate regeneration blastema, the results suggest a conserved evolutionary role of this signaling pathway in chordate regeneration. The genes identified in this investigation provide the foundation for future molecular analysis of OS regeneration. PMID:26206613

  18. The occurrence of the colonial ascidian Didemnum sp. on Georges Bank gravel habitat: ecological observations and potential effects on groundfish and scallop fisheries

    USGS Publications Warehouse

    Valentine, P.C.; Collie, J.S.; Reid, R.N.; Asch, R.G.; Guida, V.G.; Blackwood, D.S.

    2007-01-01

    The colonial ascidian Didemnum sp. is present on the Georges Bank fishing grounds in a gravel habitat where the benthic invertebrate fauna has been monitored annually since 1994. The species was not noted before 2002 when large colonies were first observed; and by 2003 and 2004 it covered large areas of the seabed at some locations. The latest survey in 2005 documented the tunicate's presence in two gravel areas that total more than 67 nm2 (230 km2). The affected area is located on the Northern Edge of the bank in United States waters near the U.S./Canada boundary ( Fig. 1). This is the first documented offshore occurrence of a species that has colonized eastern U.S. coastal waters from New York to Maine during the past 15–20 years ( U.S. Geological Survey, 2006). Video imagery shows colonies coalescing to form large mats that cover more than 50% of the seabed along some video/photo transects. The affected area is an immobile pebble and cobble pavement that lies at water depths of 40 to 65 m where strong semidiurnal tidal currents reach speeds of 1 to 2 kt (50–100 cm/s). The water column is mixed year round, ensuring a constant supply of nutrients to the seabed. Annual temperatures range from 4 to 15 °C ( Mountain and Holzwarth, 1989). The gravel areas are bounded by sand ridges whose mobile surfaces are moved daily by the strong tidal currents. Studies commenced here in 1994 to characterize the gravel habitat and to document the effects of fishing disturbance on it ( Collie et al., 2005).

  19. The Uptake and Fate of Vanadyl Ion in Ascidian Blood Cells and A Detailed Hypothesis for the Mechanism and Location of Biological Vanadium Reduction: A Visible and X-Ray Absorption Spectroscopic Study

    PubMed Central

    Frank, Patrick; Carlson, Elaine J.; Carlson, Robert M. K.; Hedman, Britt; Hodgson, Keith O.

    2010-01-01

    Vanadium K-edge x-ray absorption spectroscopy (XAS) has been used to track the uptake and fate of VO2+ ion in blood cells from Ascidia ceratodes, following exposure to dithiothreitol (DTT) or to DTT plus VO2+. The full range of endogenous vanadium was queried by fitting the XAS of blood cells with the XAS spectra of model vanadium complexes. In cells exposed only to DTT, ~0.4% of a new V(III) species was found in a site similar to Na[V(edta)(H2O)]. With exposure to DTT and VO2+, average intracellular [VO(aq)]2+ increased from 3% to 5%, and 6% of a new complexed form of vanadyl ion appeared evidencing a ligand array similar to [VO(edta)]2−. At the same time, the relative ratio of blood cell [V(H2O)6]3+ increased at the expense of [V(H2O)5(SO4)]+ in a manner consistent with a significant increase in endogenous acidity. In new UV/visible experiments, VO2+ could be reduced to 7-coordinate [V(nta)(H2O)3] or [V(nta)(ida)]2−with cysteine methyl ester in pH 6.5 solution. Ascorbate reduced [VO(edta)]2− to 7-coordinate [V(edta)(H2O)]−, while [VO(trdta)]2− was unreactive. These results corroborate the finding that the reductive EMF of VO2+ is increased by the availability of a 7-coordinate V(III) product. Finally a new and complete hypothesis is proposed for an ascidian vanadate reductase. The structure of the enzyme active site, the vanadate-vanadyl-vanadic reduction mechanism, the cellular locale, and elements of the regulatory machinery governing the biological reduction of vanadate and vanadyl ion by ascidians are all predicted. Together these constitute the new field of vanadium redox enzymology. PMID:18234345

  20. Molecular systematics of marine gregarine apicomplexans from Pacific tunicates, with descriptions of five novel species of Lankesteria.

    PubMed

    Rueckert, Sonja; Wakeman, Kevin C; Jenke-Kodama, Holger; Leander, Brian S

    2015-08-01

    The eugregarines are a group of apicomplexan parasites that mostly infect the intestines of invertebrates. The high level of morphological variation found within and among species of eugregarines makes it difficult to find consistent and reliable traits that unite even closely related lineages. Based mostly on traits observed with light microscopy, the majority of described eugregarines from marine invertebrates has been classified into a single group, the Lecudinidae. Our understanding of the overall diversity and phylogenetic relationships of lecudinids is very poor, mainly because only a modest amount of exploratory research has been done on the group and very few species of lecudinids have been characterized at the molecular phylogenetic level. In an attempt to understand the diversity of marine gregarines better, we surveyed lecudinids that infect the intestines of Pacific ascidians (i.e. sea squirts) using ultrastructural and molecular phylogenetic approaches; currently, these species fall within one genus, Lankesteria. We collected lecudinid gregarines from six ascidian host species, and our data demonstrated that each host was infected by a different species of Lankesteria: (i) Lankesteria hesperidiiformis sp. nov., isolated from Distaplia occidentalis, (ii) Lankesteria metandrocarpae sp. nov., isolated from Metandrocarpa taylori, (iii) Lankesteria halocynthiae sp. nov., isolated from Halocynthia aurantium, (iv) Lankesteria herdmaniae sp. nov., isolated from Herdmania momus, (v) Lankesteria cf. ritterellae, isolated from Ritterella rubra, and (vi) Lankesteria didemni sp. nov., isolated from Didemnum vexillum. Visualization of the trophozoites with scanning electron microscopy showed that four of these species were covered with epicytic folds, whereas two of the species were covered with a dense pattern of epicytic knobs. The molecular phylogenetic data suggested that species of Lankesteria with surface knobs form a clade that is nested within a paraphyletic

  1. Determination of toxic heavy metals in Echinodermata and Chordata species from South Korea.

    PubMed

    Choi, Ji Yeon; Habte, Girum; Khan, Naeem; Nho, Eun Yeong; Hong, Joon Ho; Choi, Hoon; Park, Kyung Su; Kim, Kyong Su

    2014-01-01

    This study aimed at analysing concentrations of heavy metals including arsenic, lead, cadmium, aluminium and mercury in commonly consumed seafood species belonging to Echinodermata (Anthocidaris crassispina and Stichopus japonicus) and Chordata (Halocynthia roretzi and Styela plicata). The samples were digested by a microwave system and analysed for As, Cd and Pb by inductively coupled plasma mass spectrometer, for Al by inductively coupled plasma-optical emission spectrometer and Hg by Direct Mercury Analyser. The analytical method was validated by determining sensitivity, linearity, precision, spiking recoveries and analysis of the Standard Reference Material (SRM) NIST 1566-b, an Oyster Tissue. Results showed considerably higher accumulation of Al and As in analysed samples, compared to Pb and Cd, while Hg had the lowest contamination. On comparison, the obtained results with the recommended standards by the Food and Agriculture Organization, European Commission and Ministry of Food and Drug Safety of Korea, it was concluded that the analysed seafoods were safe and thus would not pose a threat to consumers. PMID:24916139

  2. Ancient intron insertion sites and palindromic genomic duplication evolutionally shapes an elementally functioning membrane protein family

    PubMed Central

    Tanaka-Kunishima, Motoko; Ishida, Yoshihiro; Takahashi, Kunitaro; Honda, Motoo; Oonuma, Takashi

    2007-01-01

    Background In spite of the recent accumulation of genomic data, the evolutionary pathway in the individual genes of present-day living taxa is still elusive for most genes. Among ion channels, inward K+ rectifier (IRK) channels are the fundamental and well-defined protein group. We analyzed the genomic structures of this group and compared them among a phylogenetically wide range with our sequenced Halocynthia roretzi, a tunicate, IRK genomic genes. Results A total of 131 IRK genomic genes were analyzed. The phylogenic trees of amino acid sequences revealed a clear diversification of deuterostomic IRKs from protostomic IRKs and suggested that the tunicate IRKs are possibly representatives of the descendants of ancestor forms of three major groups of IRKs in the vertebrate. However, the exon-intron structures of the tunicate IRK genomes showed considerable similarities to those of Caenorhabditis. In the vertebrate clade, the members in each major group increased at least four times those in the tunicate by various types of global gene duplication. The generation of some major groups was inferred to be due to anti-tandem (palindromic) duplication in early history. The intron insertion points greatly decreased during the evolution of the vertebrates, remaining as a unique conservation of an intron insertion site in the portion of protein-protein interaction within the coding regions of all vertebrate G-protein-activated IRK genes. Conclusion From the genomic survey of a family of IRK genes, it was suggested that the ancient intron insertion sites and the unique palindromic genomic duplication evolutionally shaped this membrane protein family. PMID:17708769

  3. [Establishment and expression of embryonic axes: comparisons between different model organisms].

    PubMed

    Prodon, François; Prulière, Gérard; Chenevert, Janet; Sardet, Christian

    2004-05-01

    In an accompanying article (C. Sardet et al. m/s 2004; 20 : 414-423) we reviewed determinants of polarity in early development and the mechanisms which regulate their localization and expression. Such determinants have for the moment been identified in only a few species: the insect Drosophila melanogaster, the worm Caenorhabditis elegans, the frog Xenopus laevis and the ascidians Ciona intestinalis and Holocynthia roretzi. Although oogenesis, fertilization, and cell divisions in these embryos differ considerably, with respect to early polarities certain common themes emerge, such as the importance of cortical mRNAs, the PAR polarity proteins, and reorganizations mediated by the cytoskeleton. Here we highlight similarities and differences in axis establishment between these species, describing them in a chronological order from oocyte to gastrula, and add two more classical model organisms, sea urchin and mouse, to complete the comparisons depicted in the form of a Poster which can be downloaded from the site http://biodev.obs-vlfr.fr/biomarcell. PMID:15190470

  4. Genomewide gene-associated microsatellite markers for the model invasive ascidian, Ciona intestinalis species complex.

    PubMed

    Lin, Yaping; Chen, Yiyong; Xiong, Wei; Zhan, Aibin

    2016-05-01

    The vase tunicate, Ciona intestinalis species complex, has become a good model for ecological and evolutionary studies, especially those focusing on microevolution associated with rapidly changing environments. However, genomewide genetic markers are still lacking. Here, we characterized a large set of genomewide gene-associated microsatellite markers for C. intestinalis spA (=C. robusta). Bioinformatic analysis identified 4654 microsatellites from expressed sequence tags (ESTs), 2126 of which successfully assigned to chromosomes were selected for further analysis. Based on the distribution evenness on chromosomes, function annotation and suitability for primer design, we chose 545 candidate microsatellites for further characterization. After amplification validation and variation assessment, 218 loci were polymorphic in at least one of the two populations collected from the coast of Arenys de Mar, Spain (N = 24-48), and Cape Town, South Africa (N = 24-33). The number of alleles, observed heterozygosity and expected heterozygosity ranged from 2 to 11, 0 to 0.833 and 0.021 to 0.818, and from 2 to 10, 0 to 0.879 and 0.031 to 0.845 for the Spanish and African populations, respectively. When all microsatellites were tested for cross-species utility, only 60 loci (25.8%) could be successfully amplified and all loci were polymorphic in C. intestinalis spB. A high level of genomewide polymorphism is likely responsible for the low transferability. The large set of microsatellite markers characterized here is expected to provide a useful genomewide resource for ecological and evolutionary studies using C. intestinalis as a model. PMID:26505988

  5. Molecular evidence from ascidians for the evolutionary origin of vertebrate cranial sensory placodes.

    PubMed

    Mazet, Francoise; Shimeld, Sebastian M

    2005-07-15

    Cranial sensory placodes are specialised areas of the head ectoderm of vertebrate embryos that contribute to the formation of the cranial sense organs and associated ganglia. Placodes are often considered a vertebrate innovation, and their evolution has been hypothesised as one key adaptation underlying the evolution of active predation by primitive vertebrates. Here, we review recent molecular evidence pertinent to understanding the evolutionary origin of placodes. The development of vertebrate placodes is regulated by numerous genes, including members of the Pax, Six, Eya, Fox, Phox, Neurogenin and Pou gene families. In the sea squirt Ciona intestinalis (a basal chordate and close relative of the vertebrates), orthologues of these genes are deployed in the development of the oral and atrial siphons, structures used for filter feeding by the sessile adult. Our interpretation of these findings is that vertebrate placodes and sea squirt siphon primordia have evolved from the same patches of specialised ectoderm present in the common ancestor of the chordates. PMID:15981200

  6. Molecular basis of canalization in an ascidian species complex adapted to different thermal conditions

    PubMed Central

    Sato, Atsuko; Kawashima, Takeshi; Fujie, Manabu; Hughes, Samantha; Satoh, Noriyuki; Shimeld, Sebastian M.

    2015-01-01

    Canalization is a result of intrinsic developmental buffering that ensures phenotypic robustness under genetic variation and environmental perturbation. As a consequence, animal phenotypes are remarkably consistent within a species under a wide range of conditions, a property that seems contradictory to evolutionary change. Study of laboratory model species has uncovered several possible canalization mechanisms, however, we still do not understand how the level of buffering is controlled in natural populations. We exploit wild populations of the marine chordate Ciona intestinalis to show that levels of buffering are maternally inherited. Comparative transcriptomics show expression levels of genes encoding canonical chaperones such as Hsp70 and Hsp90 do not correlate with buffering. However the expression of genes encoding endoplasmic reticulum (ER) chaperones does correlate. We also show that ER chaperone genes are widely conserved amongst animals. Contrary to previous beliefs that expression level of Heat Shock Proteins (HSPs) can be used as a measurement of buffering levels, we propose that ER associated chaperones comprise a cellular basis for canalization. ER chaperones have been neglected by the fields of development, evolution and ecology, but their study will enhance understanding of both our evolutionary past and the impact of global environmental change. PMID:26577490

  7. A Maternal System Initiating the Zygotic Developmental Program through Combinatorial Repression in the Ascidian Embryo

    PubMed Central

    Oda-Ishii, Izumi; Kubo, Atsushi; Kari, Willi; Suzuki, Nobuhiro; Rothbächer, Ute

    2016-01-01

    Maternal factors initiate the zygotic developmental program in animal embryos. In embryos of the chordate, Ciona intestinalis, three maternal factors—Gata.a, β-catenin, and Zic-r.a—are required to establish three domains of gene expression at the 16-cell stage; the animal hemisphere, vegetal hemisphere, and posterior vegetal domains. Here, we show how the maternal factors establish these domains. First, only β-catenin and its effector transcription factor, Tcf7, are required to establish the vegetal hemisphere domain. Second, genes specifically expressed in the posterior vegetal domain have additional repressive cis-elements that antagonize the activity of β-catenin/Tcf7. This antagonizing activity is suppressed by Zic-r.a, which is specifically localized in the posterior vegetal domain and binds to DNA indirectly through the interaction with Tcf7. Third, Gata.a directs specific gene expression in the animal hemisphere domain, because β-catenin/Tcf7 weakens the Gata.a-binding activity for target sites through a physical interaction in the vegetal cells. Thus, repressive regulation through protein-protein interactions among the maternal transcription factors is essential to establish the first distinct domains of gene expression in the chordate embryo. PMID:27152625

  8. Hox10-regulated endodermal cell migration is essential for development of the ascidian intestine.

    PubMed

    Kawai, Narudo; Ogura, Yosuke; Ikuta, Tetsuro; Saiga, Hidetoshi; Hamada, Mayuko; Sakuma, Tetsushi; Yamamoto, Takashi; Satoh, Nori; Sasakura, Yasunori

    2015-07-01

    Hox cluster genes play crucial roles in development of the metazoan antero-posterior axis. Functions of Hox genes in patterning the central nervous system and limb buds are well known. They are also expressed in chordate endodermal tissues, where their roles in endodermal development are still poorly understood. In the invertebrate chordate, Ciona intestinalis, endodermal tissues are in a premature state during the larval stage, and they differentiate into the digestive tract during metamorphosis. In this study, we showed that disruption of a Hox gene, Ci-Hox10, prevented intestinal formation. Ci-Hox10-knock-down larvae displayed defective migration of endodermal strand cells. Formation of a protrusion, which is important for cell migration, was disrupted in these cells. The collagen type IX gene is a downstream target of Ci-Hox10, and is negatively regulated by Ci-Hox10 and a matrix metalloproteinase ortholog, prior to endodermal cell migration. Inhibition of this regulation prevented cellular migration. These results suggest that Ci-Hox10 regulates endodermal strand cell migration by forming a protrusion and by reconstructing the extracellular matrix. PMID:25888074

  9. Evaluation of drug toxicity profiles based on the phenotypes of ascidian Ciona intestinalis.

    PubMed

    Mizotani, Yuji; Itoh, Shun; Hotta, Kohji; Tashiro, Etsu; Oka, Kotaro; Imoto, Masaya

    2015-08-01

    In vivo toxicity evaluation using model organisms is an important step for the development of new drugs. Here, we report that Ciona intestinalis, a chordate invertebrate, is beneficial to drug toxicity evaluation for the following reasons: rapid embryonic and larval development, resemblance to vertebrates, ease of management, low cost, transparent body, and low risk of ethical issues. The dynamic phenotypic change of Ciona larvae during metamorphosis prompted us to examine the effect of cytotoxic drugs on its development by quantifying six toxicity endpoints: degenerated tail size, ampulla length, rotation of body axis, stomach size, heart rate, and body size. As a result, mitochondrial respiratory inhibitors, tubulin polymerization/depolymerization inhibitors, or DNA/RNA synthesis inhibitors showed distinct toxicity profiles against these six endpoints, but drugs with the same targets showed a similar toxicity profile in Ciona. Our results suggest Ciona is an effective animal model for profiling drug toxicity and exploring the mechanisms of drugs with unknown targets. PMID:26043689

  10. Myelin tetraspan family proteins but no non-tetraspan family proteins are present in the ascidian (Ciona intestinalis) genome.

    PubMed

    Gould, Robert M; Morrison, Hilary G; Gilland, Edwin; Campbell, Robert K

    2005-08-01

    Several of the proteins used to form and maintain myelin sheaths in the central nervous system (CNS) and the peripheral nervous system (PNS) are shared among different vertebrate classes. These proteins include one-to-several alternatively spliced myelin basic protein (MBP) isoforms in all sheaths, proteolipid protein (PLP) and DM20 (except in amphibians) in tetrapod CNS sheaths, and one or two protein zero (P0) isoforms in fish CNS and in all vertebrate PNS sheaths. Several other proteins, including 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP), myelin and lymphocyte protein (MAL), plasmolipin, and peripheral myelin protein 22 (PMP22; prominent in PNS myelin), are localized to myelin and myelin-associated membranes, though class distributions are less well studied. Databases with known and identified sequences of these proteins from cartilaginous and teleost fishes, amphibians, reptiles, birds, and mammals were prepared and used to search for potential homologs in the basal vertebrate, Ciona intestinalis. Homologs of lipophilin proteins, MAL/plasmolipin, and PMP22 were identified in the Ciona genome. In contrast, no MBP, P0, or CNP homologs were found. These studies provide a framework for understanding how myelin proteins were recruited during evolution and how structural adaptations enabled them to play key roles in myelination. PMID:16110093

  11. Transcriptome characterization of the ascidian Pyura chilensis using 454-pyrosequencing data from two distant localities on the southeast Pacific.

    PubMed

    Haye, Pilar A; Gallardo-Escárate, Cristian

    2015-04-01

    This study describes the results from transcriptomes sequenced by 454-pyrosequencing from two populations separated by 10° of latitude of the endemic tunicate Pyura chilensis. Most transcripts were assembled in 43,972 contigs with an average length of 842 nucleotides. De novo assembly revealed that less than 30% of the contigs were annotated to Gene Ontology terms. A total of 71,662 single nucleotide polymorphisms (SNPs) were detected in 14,712 contigs. In silico differential expression of contigs annotated for SNPs revealed several genes differentially expressed in individuals collected from both populations. The present genomic resource will provide the basis to perform functional genomics on the species via the localization of genomic markers that can aid in determining levels of local adaptation, overall genetic structure and the genetic assessment of restocking programs for this species. PMID:25526667

  12. The Non-Proliferative Nature of Ascidian Folliculogenesis as a Model of Highly Ordered Cellular Topology Distinct from Proliferative Epithelia

    PubMed Central

    Azzag, Karim; Chelin, Yoann; Rousset, François; Le Goff, Emilie; Martinand-Mari, Camille; Martinez, Anne-Marie; Maurin, Bernard; Daujat-Chavanieu, Martine; Godefroy, Nelly; Averseng, Julien; Mangeat, Paul; Baghdiguian, Stephen

    2015-01-01

    Previous studies have addressed why and how mono‐stratified epithelia adopt a polygonal topology. One major additional, and yet unanswered question is how the frequency of different cell shapes is achieved and whether the same distribution applies between non-proliferative and proliferative epithelia. We compared different proliferative and non-proliferative epithelia from a range of organisms as well as Drosophila melanogaster mutants, deficient for apoptosis or hyperproliferative. We show that the distribution of cell shapes in non‐proliferative epithelia (follicular cells of five species of tunicates) is distinctly, and more stringently organized than proliferative ones (cultured epithelial cells and Drosophila melanogaster imaginal discs). The discrepancy is not supported by geometrical constraints (spherical versus flat monolayers), number of cells, or apoptosis events. We have developed a theoretical model of epithelial morphogenesis, based on the physics of divided media, that takes into account biological parameters such as cell‐cell contact adhesions and tensions, cell and tissue growth, and which reproduces the effects of proliferation by increasing the topological heterogeneity observed experimentally. We therefore present a model for the morphogenesis of epithelia where, in a proliferative context, an extended distribution of cell shapes (range of 4 to 10 neighbors per cell) contrasts with the narrower range of 5-7 neighbors per cell that characterizes non proliferative epithelia. PMID:26000769

  13. Molecular orbital calculations, experimental and theoretical UV spectra of granulatimides and didemnimides, biologically active polycyclic heteroaromatic alkaloids from the ascidian Didemnum granulatum

    NASA Astrophysics Data System (ADS)

    Camargo, A. J.; Oliveira, J. H. H. L.; Trsic, M.; Berlinck, R. G. S.

    2001-01-01

    A detailed computational study was performed for compounds granulatimide, isogranulatimide, and didemnimides A, D, and E, using the semiempirical Austin model 1 quantum chemical method. The electronic features and structural parameters were confronted with the inhibition of the G2 cell cycle checkpoint of mammalian cancer cells. All compounds were submitted to a rigorous conformational analysis using the Tripos 5.2 force field implemented in the Spartan 5.01 program. The electronic density in specific regions of the molecules appears to play a pivotal role towards activity. The molecular planarity creates a broad negative electrostatic potential on the two sides of the active compounds (granulatimide and isogralulatimide) and a positive potential in their central core, while the non-planar compounds (didemnimides A, D, and E, which are inactive) present an asymmetric potential scattered over the molecules. These electrostatic potential features are likely to be the modulator of hydrophobicity or lipophilicity of the compounds, which appear correlated with activity. The hydrogen attached to the N atom of the pyrrole moiety of indole is more positive for active compounds than for the inactive molecules. The theoretical electronic spectra were obtained for all compounds using the configuration interaction method, with the AM1 routine. All transitions present π→π ∗ nature. The theoretical results are in good agreement with experimental values.

  14. The ascidian natural product eusynstyelamide B is a novel topoisomerase II poison that induces DNA damage and growth arrest in prostate and breast cancer cells

    PubMed Central

    Liberio, Michelle S.; Sadowski, Martin C.; Davis, Rohan A.; Rockstroh, Anja; Vasireddy, Raj; Lehman, Melanie L.; Nelson, Colleen C.

    2015-01-01

    As part of an anti-cancer natural product drug discovery program, we recently identified eusynstyelamide B (EB), which displayed cytotoxicity against MDA-MB-231 breast cancer cells (IC50 = 5 μM) and induced apoptosis. Here, we investigated the mechanism of action of EB in cancer cell lines of the prostate (LNCaP) and breast (MDA-MB-231). EB inhibited cell growth (IC50 = 5 μM) and induced a G2 cell cycle arrest, as shown by a significant increase in the G2/M cell population in the absence of elevated levels of the mitotic marker phospho-histone H3. In contrast to MDA-MB-231 cells, EB did not induce cell death in LNCaP cells when treated for up to 10 days. Transcript profiling and Ingenuity Pathway Analysis suggested that EB activated DNA damage pathways in LNCaP cells. Consistent with this, CHK2 phosphorylation was increased, p21CIP1/WAF1 was up-regulated and CDC2 expression strongly reduced by EB. Importantly, EB caused DNA double-strand breaks, yet did not directly interact with DNA. Analysis of topoisomerase II-mediated decatenation discovered that EB is a novel topoisomerase II poison. PMID:26733491

  15. Endozoicomonas Are Specific, Facultative Symbionts of Sea Squirts

    PubMed Central

    Schreiber, Lars; Kjeldsen, Kasper U.; Funch, Peter; Jensen, Jeppe; Obst, Matthias; López-Legentil, Susanna; Schramm, Andreas

    2016-01-01

    Ascidians are marine filter feeders and harbor diverse microbiota that can exhibit a high degree of host-specificity. Pharyngeal samples of Scandinavian and Mediterranean ascidians were screened for consistently associated bacteria by culture-dependent and -independent approaches. Representatives of the Endozoicomonas (Gammaproteobacteria, Hahellaceae) clade were detected in the ascidian species Ascidiella aspersa, Ascidiella scabra, Botryllus schlosseri, Ciona intestinalis, Styela clava, and multiple Ascidia/Ascidiella spp. In total, Endozoicomonas was detected in more than half of all specimens screened, and in 25–100% of the specimens for each species. The retrieved Endozoicomonas 16S rRNA gene sequences formed an ascidian-specific subclade, whose members were detected by fluorescence in situ hybridization (FISH) as extracellular microcolonies in the pharynx. Two strains of the ascidian-specific Endozoicomonas subclade were isolated in pure culture and characterized. Both strains are chemoorganoheterotrophs and grow on mucin (a mucus glycoprotein). The strains tested negative for cytotoxic or antibacterial activity. Based on these observations, we propose ascidian-associated Endozoicomonas to be commensals, living off the mucus continuously secreted into the pharynx. Members of the ascidian-specific Endozoicomonas subclade were also detected in seawater from the Scandinavian sampling site, which suggests acquisition of the symbionts by horizontal transmission. The combined results indicate a host-specific, yet facultative symbiosis between ascidians and Endozoicomonas. PMID:27462299

  16. Endozoicomonas Are Specific, Facultative Symbionts of Sea Squirts.

    PubMed

    Schreiber, Lars; Kjeldsen, Kasper U; Funch, Peter; Jensen, Jeppe; Obst, Matthias; López-Legentil, Susanna; Schramm, Andreas

    2016-01-01

    Ascidians are marine filter feeders and harbor diverse microbiota that can exhibit a high degree of host-specificity. Pharyngeal samples of Scandinavian and Mediterranean ascidians were screened for consistently associated bacteria by culture-dependent and -independent approaches. Representatives of the Endozoicomonas (Gammaproteobacteria, Hahellaceae) clade were detected in the ascidian species Ascidiella aspersa, Ascidiella scabra, Botryllus schlosseri, Ciona intestinalis, Styela clava, and multiple Ascidia/Ascidiella spp. In total, Endozoicomonas was detected in more than half of all specimens screened, and in 25-100% of the specimens for each species. The retrieved Endozoicomonas 16S rRNA gene sequences formed an ascidian-specific subclade, whose members were detected by fluorescence in situ hybridization (FISH) as extracellular microcolonies in the pharynx. Two strains of the ascidian-specific Endozoicomonas subclade were isolated in pure culture and characterized. Both strains are chemoorganoheterotrophs and grow on mucin (a mucus glycoprotein). The strains tested negative for cytotoxic or antibacterial activity. Based on these observations, we propose ascidian-associated Endozoicomonas to be commensals, living off the mucus continuously secreted into the pharynx. Members of the ascidian-specific Endozoicomonas subclade were also detected in seawater from the Scandinavian sampling site, which suggests acquisition of the symbionts by horizontal transmission. The combined results indicate a host-specific, yet facultative symbiosis between ascidians and Endozoicomonas. PMID:27462299

  17. Relationships between deep-sea tunicate populations west and east of the Straits of Gibraltar

    NASA Astrophysics Data System (ADS)

    Monniot, Claude; Monniot, Françoise

    Twenty-four species of tunicates were collected from deep bottoms on each side of the Gibraltar sill, in the adjacent Mediterranean Sea and Atlantic Ocean. In the Atlantic, stations bathed by Atlantic and Mediterranean waters were both sampled. No transport of ascidian taxa by the outflow of Mediterranean water into the Atlantic is apparent. The alternative hypothesis of an Atlantic origin of bathyal ascidian species in the Mediterranean Sea is proposed.

  18. Origin and Variation of Tunicate Secondary Metabolites⊥

    PubMed Central

    Schmidt, Eric W.; Donia, Mohamed S.; McIntosh, John A.; Fricke, W. Florian; Ravel, Jacques

    2012-01-01

    Ascidians (tunicates) are rich sources of structurally elegant, pharmaceutically potent secondary metabolites and more recently, potential biofuels. It has been demonstrated that some of these compounds are made by symbiotic bacteria and not by the animals themselves, and for a few other compounds evidence exists supporting a symbiotic origin. In didemnid ascidians, compounds are highly variable even in apparently identical animals. Recently, we have explained this variation at the genomic and metagenomic levels and have applied the basic scientific findings to drug discovery and development. This review discusses what is currently known about the origin and variation of symbiotically derived metabolites in ascidians, focusing on Family Didemnidae, where most research has occurred. Applications of our basic studies are also described. PMID:22233390

  19. Styela clava Herdman (Urochordata, Ascidiacea), a successful immigrant to North West Europe: ecology, propagation and chronology of spread

    NASA Astrophysics Data System (ADS)

    Lützen, J.

    1998-09-01

    Since its first occurrence at Plymouth, southern England, in 1952 the East Asiatic ascidian Styela clava has spread to many localities along the coasts of the south and west British Isles, Ireland, northern France, Belgium, the Netherlands, Denmark and Germany. While some dispersal may occur by natural means, spreading over long distances is probably due to transfer along with oysters when relaid elsewhere. Transport while attached to the hulls of ships or drifting Sargassum is also possible. Styela clava is a large, hardy and fast-growing species with a tough, leathery tunic, and has no recorded enemies or native analogues among the NW European ascidian fauna. At many sites it has established dense populations of 500-1000 specimens/m2 and in some cases has nearly outcompeted some of the native ascidian species.

  20. Recent N-Atom Containing Compounds from Indo-Pacific Invertebrates

    PubMed Central

    Kashman, Yoel; Bishara, Ashgan; Aknin, Maurice

    2010-01-01

    A large variety of unique N-atom containing compounds (alkaloids) without terrestrial counterparts, have been isolated from marine invertebrates, mainly sponges and ascidians. Many of these compounds display interesting biological activities. In this report we present studies on nitrogenous compounds, isolated by our group during the last few years, from Indo-Pacific sponges, one ascidian and one gorgonian. The major part of the review deals with metabolites from the Madagascar sponge Fascaplysinopsis sp., namely, four groups of secondary metabolites, the salarins, tulearins, taumycins and tausalarins. PMID:21139846

  1. ACAM, a novel member of the neural IgCAM family, mediates anterior neural tube closure in a primitive chordate.

    PubMed

    Morales Diaz, Heidi; Mejares, Emil; Newman-Smith, Erin; Smith, William C

    2016-01-01

    The neural IgCAM family of cell adhesion molecules, which includes NCAM and related molecules, has evolved via gene duplication and alternative splicing to allow for a wide range of isoforms with distinct functions and homophilic binding properties. A search for neural IgCAMs in ascidians (Ciona intestinalis, Ciona savignyi, and Phallusia mammillata) has identified a novel set of truncated family members that, unlike the known members, lack fibronectin III domains and consist of only repeated Ig domains. Within the tunicates this form appears to be unique to the ascidians, and it was designated ACAM, for Ascidian Cell Adhesion Molecule. In C. intestinalis ACAM is expressed in the developing neural plate and neural tube, with strongest expression in the anterior sensory vesicle precursor. Unlike the two other conventional neural IgCAMs in C. intestinalis, which are expressed maternally and throughout the morula and blastula stages, ACAM expression initiates at the gastrula stage. Moreover, C. intestinalis ACAM is a target of the homeodomain transcription factor OTX, which plays an essential role in the development of the anterior central nervous system. Morpholino (MO) knockdown shows that ACAM is required for neural tube closure. In MO-injected embryos neural tube closure was normal caudally, but the anterior neuropore remained open. A similar phenotype was seen with overexpression of a secreted version of ACAM. The presence of ACAM in ascidians highlights the diversity of this gene family in morphogenesis and neurodevelopment. PMID:26542009

  2. How the sea squirt nucleus tells mesoderm Not to be endoderm

    PubMed Central

    Parton, Richard M.; Davis, Ilan

    2011-01-01

    Sea squirts are simple invertebrate chordates. In this issue, Takatori et al show nuclear migration within ascidian mesendodermal cells enables polarized localization of Not mRNA, which encodes a homeobox protein that distinguishes mesoderm from endoderm fates. The link between nuclear migration and mRNA localization suggests exciting parallels with protostomes. PMID:20951340

  3. Has innate immunity evolved through different routes?

    NASA Astrophysics Data System (ADS)

    Parrinello, Nicolò

    2010-03-01

    Invertebrate self/non-self recognition, defense responses, mating and development share innate immune surveillance and functions challenged by competition and linked to fitness. Independent evolutionary branches of immune responses may use conserved gene traits. On the other hand immunity genes may be conserved due to their role in development. Finally, upregulation of innate immunity genes during ascidian metamorphosis supports the danger hypothesis.

  4. Screening for antioxidant and detoxification responses in Perna canaliculus Gmelin exposed to an antifouling bioactive intended for use in aquaculture.

    PubMed

    Cahill, Patrick Louis; Burritt, David; Heasman, Kevin; Jeffs, Andrew; Kuhajek, Jeanne

    2013-10-01

    Polygodial is a drimane sesquiterpene dialdehyde derived from certain terrestrial plant species that potently inhibits ascidian metamorphosis, and thus has potential for controlling fouling ascidians in bivalve aquaculture. The current study examined the effects of polygodial on a range of biochemical biomarkers of oxidative stress and detoxification effort in the gills of adult Perna canaliculus Gmelin. Despite high statistical power and the success of positive controls, the antioxidant enzymes glutathione reductase (GR), glutathione peroxidase (GPOX), catalase (CAT), and superoxide dismutase (SOD); thiol status, as measured by total glutathione (GSH-t), glutathione disulphide (GSSG), and GSH-t/GSSG ratio; end products of oxidative damage, lipid hydroperoxides (LHPO) and protein carbonyls; and detoxification pathways, represented by GSH-t and glutathione S-transferase (GST), were unaffected in the gills of adult P. canaliculus exposed to polygodial at 0.1 or 1 × the 99% effective dose in fouling ascidians (IC₉₉). Similarly, GR levels, thiol status, and detoxification activities were unaffected in mussels exposed to polygodial at 10 × the IC₉₉, although GPOX, CAT, and SOD activities increased. However, the increases were small relative to positive controls, no corresponding oxidative damage was detected, and this concentration greatly exceeds effective doses required to inhibit fouling ascidians in aquaculture. These findings compliment a previous study that established the insensitivity to polygodial of P. canaliculus growth, condition, and mitochondrial functioning, providing additional support for the suitability of polygodial for use as an antifouling agent in bivalve aquaculture. PMID:23830117

  5. Lectins of marine hydrobionts.

    PubMed

    Chernikov, O V; Molchanova, V I; Chikalovets, I V; Kondrashina, A S; Li, W; Lukyanov, P A

    2013-07-01

    Data from the literature and results of our research on lectins isolated from some kinds of marine hydrobionts such as clams, ascidians, sea worms, sponges, and algae are presented in this review. Results of comparative analysis of the basic physicochemical properties and biological activity of lectins isolated from various sources are discussed. PMID:24010839

  6. Prochloron on synaptula

    NASA Technical Reports Server (NTRS)

    Cheng, L.; Lewin, R. A.

    1983-01-01

    It is reported that, for the first time, Prochloron cells were found associated with an animal other than a colonial ascidian-namely, a synaptid holothurian, Snaptula lamperti. This occurance brings into question the supposedly obligate nature of the association of this problematic algae with didemnids and their allies.

  7. Role of cyclic AMP in the maturation of Ciona intestinalis oocytes.

    PubMed

    Silvestre, Francesco; Gallo, Alessandra; Cuomo, Annunziata; Covino, Tiziana; Tosti, Elisabetta

    2011-11-01

    Immature oocytes are arrested at prophase I of the meiotic process and maturation onset is indicated by oocyte nuclear disassembly (germinal vesicle breakdown or GVBD). Signaling pathways that elevate intracellular cyclic AMP (cAMP) may either prevent or induce oocyte maturation depending on the species. In some marine invertebrates and, in particular, in ascidian oocytes, cAMP triggers GVBD rather than blocking it. In this paper, we tested different cAMP elevators in fully grown oocytes at the germinal vesicle stage (GV) of the ascidian Ciona intestinalis. We demonstrated that through the activation of adenylate cyclase or the inhibition and phosphodiesterases the oocyte remained at the GV stage. This effect was reversible as the GV-arrested oocytes, rinsed and incubated in sea water, are able to undergo spontaneous maturation and extrusion of follicle cells. In addition, oocytes acquire the ability to be fertilized and start early development. However, morphology of follicle cells, embryos and larvae from in vitro matured oocytes showed different morphology from those derived from in vivo mature oocytes. The role and the transduction mechanism of cAMP in the regulation of oocyte maturation were discussed. Finally, we indicated a variation of biological mechanisms present in the ascidian species; moreover, we sustain evidence proving that tunicates share some biological mechanisms with vertebrates. This information provided new hints on the importance of ascidians in the evolution of chordates. PMID:20810008

  8. How the sea squirt nucleus tells mesoderm not to be endoderm.

    PubMed

    Parton, Richard M; Davis, Ilan

    2010-10-19

    Sea squirts are simple invertebrate chordates. In this issue of Developmental Cell, Takatori et al. show nuclear migration within ascidian mesendodermal cells enables polarized localization of Not mRNA, which encodes a homeobox protein that distinguishes mesoderm from endoderm fates. The link between nuclear migration and mRNA localization suggests exciting parallels with protostomes. PMID:20951340

  9. The habitat engineering tunicate Microcosmus sabatieri Roule, 1885 and its associated peracarid epifauna

    NASA Astrophysics Data System (ADS)

    Voultsiadou, Eleni; Pyrounaki, Maria-Myrto; Chintiroglou, Chariton

    2007-08-01

    The solitary ascidian Microcosmus sabatieri is a common ecosystem engineering species on hard bottom sublittoral communities in the Eastern Mediterranean. Peracarida are common inhabitants of biological substrata, such as algae, sponges and ascidians and have been proven to be very sensitive to changes in environmental conditions. The aim of this study was to present and analyse, for the first time, the structure of the peracarid epifaunal assemblage inhabiting this Mediterranean endemic, edible and commercially exploited species. During sampling in the North Aegean Sea, 41 specimens were collected and examined for their peracarid epifauna. Overall, 38 peracarid species were identified, a high number in comparison to those recorded in the few other relevant studies on ascidian epifauna. The great majority of the species were amphipods. By contrast, in terms of abundance, tanaidaceans was the dominant taxon, with Leptochelia savigni being by far the most dominant species. Tube-dwelling suspension-feeders dominated the peracarid epifauna of this tunicate. The suspension feeding mode of epifaunal peracarids is possibly favoured by the high filtration rate of M. sabatieri which is large sized and has an extensive branchial surface. It is suggested that the tube-dwelling habit of tanaidaceans and some amphipods offering extra protection, may further explain their dominance as elements of the epifauna, in contrast to other inquiline peracarids which prefer to search for shelter inside the canals of sponges or, in a few cases inside the mantle cavity of ascidians. Differences in peracarid abundance among the ascidian specimens were attributed to the reproductive and dispersal habits of the former. Species richness, abundance and diversity of the motile peracarid epifauna was dependent on the biomass of the ascidian, but most strongly on the biomass of the sessile epibiontic organisms, such as algae and sponges which, in some cases, had a higher biomass than the ascidian

  10. Analysis of Plasmalogen Species in Foodstuffs.

    PubMed

    Yamashita, Shinji; Kanno, Susumu; Honjo, Ayako; Otoki, Yurika; Nakagawa, Kiyotaka; Kinoshita, Mikio; Miyazawa, Teruo

    2016-02-01

    Ethanolamine plasmalogen (PlsEtn), which is present at high levels in brains, is believed to be involved in neuronal protection. The present study was performed to search for PlsEtn resources in foodstuffs. The foodstuffs examined showed a wide range of PlsEtn contents from 5 to 549 μmol/100 g wet wt. The marine invertebrates, blue mussel, and ascidian had high PlsEtn contents (over 200 μmol/100 g wet wt). Profiling of the molecular species showed that the predominant fatty acids of PlsEtn species were 20:5 (EPA) and 22:6 (DHA) at the sn-2 position of the glycerol moiety in marine foodstuffs, whereas major PlsEtn species in land foodstuffs were 20:4. Following quantitative analysis by multiple reaction monitoring, the ascidian viscera were shown to contain the highest levels of 18:0/20:5-PlsEtn and 18:0/22:6-PlsEtn (86 and 68 μmol/100 g wet wt, respectively). In order to evaluate a neuronal antiapoptotic effect of these PlsEtn species, human neuroblastoma SH-SY5Y cells were treated with ethanolamine glycerophospholipid (EtnGpl), purified from the ascidian viscera, under serum starvation conditions. Extrinsic EtnGpl from ascidian viscera showed stronger suppression of cell death induced by serum starvation than with bovine brain EtnGpl. The EtnGpl from ascidian viscera strongly suppressed the activation of caspase 3. These results suggest that PlsEtn, especially that containing EPA and DHA, from marine foodstuffs is potentially useful for a therapeutic dietary supplement preventing neurodegenerative diseases, such as Alzheimer's disease (AD). PMID:26732602

  11. Details of the evolutionary history from invertebrates to vertebrates, as deduced from the sequences of 18S rDNA.

    PubMed Central

    Wada, H; Satoh, N

    1994-01-01

    Almost the entire sequences of 18S rDNA were determined for two chaetognaths, five echinoderms, a hemichordate, and two urochordates (a larvacean and a salp). Phylogenetic comparisons of the sequences, together with those of other deuterostomes (an ascidian, a cephalochordate, and vertebrates) and protostomes (an arthropod and a mollusc), suggest the monophyly of the deuterostomes, with the exception of the chaetognaths. Chaetognaths may not be a group of deuterostomes. The deuterostome group closest to vertebrates was the group of cephalochordates. Ascidians, larvaceans, and salps seem to form a discrete group (urochordates), in which the early divergence of larvaceans is evident. These results support the hypothesis that chordates evolved from free-living ancestors. PMID:8127885

  12. Two new species of Distaplia (Tunicata: Ascidiacea) from the SW Atlantic, Argentina.

    PubMed

    Lagger, Cristian; Tatián, Marcos

    2013-01-01

    The ascidian fauna from the Southwestern Atlantic (Argentine Sea) have scarcely been studied and have rarely been sampled. The existing scanty ascidian records are from specimens collected by dredging many decades ago. During samplings in the San Matias Gulf (Río Negro, Patagonia), two new Distaplia species were found. Distaplia naufragii sp. nov. was collected in the subtidal zone attached to a shipwreck, while the other species, Distaplia fortuita sp. nov. was found released by the tides in the sandy intertidal zone. These two new species differ deeply from each other in the size and morphology of their zooids. They represent one third of the known species belonging to the family Holozoidae in the SW Atlantic. These results reinforce the importance of new studies in this extensive but little explored area that is, in addition, susceptible to invasion by non-native species. PMID:26120704

  13. Contaminant cocktails: Interactive effects of fertiliser and copper paint on marine invertebrate recruitment and mortality.

    PubMed

    Lawes, Jasmin C; Clark, Graeme F; Johnston, Emma L

    2016-01-15

    Understanding interactive effects of contaminants is critical to predict how human activities change ecosystem structure and function. We examined independent and interactive effects of two contaminants (fertiliser and copper paint) on the recruitment, mortality, and total abundance of developing invertebrate communities in the field, 2, 4, 6, and 8 weeks after substrate submersion. Contaminants affected community structure differently, and produced an intermediate community in combination. Fertiliser increased recruitment and decreased mortality of active filter feeders (ascidians and barnacles), while copper paint decreased recruitment and increased mortality of some taxa. Contaminants applied together affected some taxa (e.g. Didemnid ascidians) antagonistically, as fertiliser mitigated adverse effects of copper paint. Recruitment of active filter feeders appears to be indicative of nutrient enrichment, and their increased abundance may reduce elevated nutrients in modified waterways. This study demonstrates the need to consider both independent and interactive effects of contaminants on marine communities in the field. PMID:26632524

  14. Structure and function of vanadium compounds in living organisms.

    PubMed

    Rehder, D

    1992-01-01

    Vanadium has been recognized as a metal of biological importance only recently. In this mini-review, its main functions uncovered during the past few years are addressed. These encompass (i) the regulation of phosphate metabolizing enzymes (which is exemplified for the inhibition of ribonucleases by vanadate), (ii) the halogenation of organic compounds by vanadate-dependent non-heme peroxidases from seaweeds, (iii) the reductive protonation of nitrogen (nitrogen fixation) by alternative, i.e. vanadium-containing, nitrogenases from N2-fixing bacteria, (iv) vanadium sequestering by sea squirts (ascidians), and (v) amavadine, a low molecular weight complex of V(IV) accumulated in the fly agaric and related toadstools. The function of vanadium, while still illusive in ascidians and toadstools, begins to be understood in vanadium-enzyme interaction. Investigations into the structure and function of model compounds play an increasingly important role in elucidating the biological significance of vanadium. PMID:1392470

  15. Effects of simulated eutrophication and overfishing on algae and invertebrate settlement in a coral reef of Koh Phangan, Gulf of Thailand.

    PubMed

    Stuhldreier, Ines; Bastian, Pepe; Schönig, Eike; Wild, Christian

    2015-03-15

    Coral reefs in the Gulf of Thailand are highly under-investigated regarding responses to anthropogenic stressors. Thus, this study simulated overfishing and eutrophication using herbivore exclosure cages and slow-release fertilizer to study the in-situ effects on benthic algae and invertebrate settlement in a coral reef of Koh Phangan, Thailand. Settlement of organisms and the development of organic matter on light-exposed and shaded tiles were quantified weekly/biweekly over a study period of 12 weeks. Simulated eutrophication did not significantly influence response parameters, while simulated overfishing positively affected dry mass, turf algae height and fleshy macroalgae occurrence on light-exposed tiles. On shaded tiles, settlement of crustose coralline algae decreased, while abundances of ascidians increased compared to controls. An interactive effect of both stressors was not observed. These results hint to herbivory as actual key controlling factor on the benthic community, and fleshy macroalgae together with ascidians as potential bioindicators for local overfishing. PMID:25649838

  16. Sialic acids as link to Japanese scientists.

    PubMed

    Schauer, Roland

    2016-01-01

    This manuscript is dedicated to Prof. Tamio Yamakawa and describes my cooperations on sialic acid-related topics with Japanese scientists during the last 40 years. We studied sialic acids and their O-acetylated derivatives in the sea urchin Pseudocentrotus depressus, in Halocynthia species, and in human and bovine milk. In seafood we mainly searched for N-glycolylneuraminic acid. With synthetic substrates it was shown that sialic acid O-acetylation at C-4 hinders the activity of sialidases, with the exception of viral enzymes. The biosynthesis of Neu5Gc was discussed and the distribution of this sialic acid in dogs followed in modern literature and reviewed regarding their migration. An excellent source of sialic acids is edible bird nest substance (Collocalia mucin) which was used for the synthesis of sialylation inhibitors. PMID:27063181

  17. Phallusiasterol C, A New Disulfated Steroid from the Mediterranean Tunicate Phallusia fumigata.

    PubMed

    Imperatore, Concetta; Senese, Maria; Aiello, Anna; Luciano, Paolo; Fiorucci, Stefano; D'Amore, Claudio; Carino, Adriana; Menna, Marialuisa

    2016-01-01

    A new sulfated sterol, phallusiasterol C (1), has been isolated from the Mediterranean ascidian Phallusia fumigata and its structure has been determined on the basis of extensive spectroscopic (mainly 2D NMR) analysis. The possible role in regulating the pregnane X receptor (PXR) activity of phallusiasterol C has been investigated; although the new sterol resulted inactive, this study adds more items to the knowledge of the structure-PXR regulating activity relationships in the case of sulfated steroids. PMID:27322293

  18. Phallusiasterol C, A New Disulfated Steroid from the Mediterranean Tunicate Phallusia fumigata

    PubMed Central

    Imperatore, Concetta; Senese, Maria; Aiello, Anna; Luciano, Paolo; Fiorucci, Stefano; D’Amore, Claudio; Carino, Adriana; Menna, Marialuisa

    2016-01-01

    A new sulfated sterol, phallusiasterol C (1), has been isolated from the Mediterranean ascidian Phallusia fumigata and its structure has been determined on the basis of extensive spectroscopic (mainly 2D NMR) analysis. The possible role in regulating the pregnane X receptor (PXR) activity of phallusiasterol C has been investigated; although the new sterol resulted inactive, this study adds more items to the knowledge of the structure-PXR regulating activity relationships in the case of sulfated steroids. PMID:27322293

  19. Marine Natural Meroterpenes: Synthesis and Antiproliferative Activity

    PubMed Central

    Simon-Levert, Annabel; Menniti, Christophe; Soulère, Laurent; Genevière, Anne-Marie; Barthomeuf, Chantal; Banaigs, Bernard; Witczak, Anne

    2010-01-01

    Meroterpenes are compounds of mixed biogenesis, isolated from plants, microorganisms and marine invertebrates. We have previously isolated and determined the structure for a series of meroterpenes extracted from the ascidian Aplidium aff. densum. Here, we demonstrate the chemical synthesis of three of them and their derivatives, and evaluate their biological activity on two bacterial strains, on sea urchin eggs, and on cancerous and healthy human cells. PMID:20390109

  20. Acidification effects on biofouling communities: winners and losers.

    PubMed

    Peck, Lloyd S; Clark, Melody S; Power, Deborah; Reis, João; Batista, Frederico M; Harper, Elizabeth M

    2015-05-01

    How ocean acidification affects marine life is a major concern for science and society. However, its impacts on encrusting biofouling communities, that are both the initial colonizers of hard substrata and of great economic importance, are almost unknown. We showed that community composition changed significantly, from 92% spirorbids, 3% ascidians and 4% sponges initially to 47% spirorbids, 23% ascidians and 29% sponges after 100 days in acidified conditions (pH 7.7). In low pH, numbers of the spirorbid Neodexiospira pseudocorrugata were reduced ×5 compared to controls. The two ascidians present behaved differently with Aplidium sp. decreasing ×10 in pH 7.7, whereas Molgula sp. numbers were ×4 higher in low pH than controls. Calcareous sponge (Leucosolenia sp.) numbers increased ×2.5 in pH 7.7 over controls. The diatom and filamentous algal community was also more poorly developed in the low pH treatments compared to controls. Colonization of new surfaces likewise showed large decreases in spirorbid numbers, but numbers of sponges and Molgula sp. increased. Spirorbid losses appeared due to both recruitment failure and loss of existing tubes. Spirorbid tubes are comprised of a loose prismatic fabric of calcite crystals. Loss of tube materials appeared due to changes in the binding matrix and not crystal dissolution, as SEM analyses showed crystal surfaces were not pitted or dissolved in low pH conditions. Biofouling communities face dramatic future changes with reductions in groups with hard exposed exoskeletons and domination by soft-bodied ascidians and sponges. PMID:25626420

  1. Biogeography of Phallusia nigra: is it really black and white?

    PubMed

    Vandepas, Lauren E; Oliveira, Livia M; Lee, Serina S C; Hirose, Euichi; Rocha, Rosana M; Swalla, Billie J

    2015-02-01

    Ascidians (Chordata, Tunicata) are an important group for the study of invasive species biology due to rapid generation times, potential for biofouling, and role as filter feeders in an ecosystem. Phallusia nigra is a putative cosmopolitan ascidian that has been described as introduced or invasive in a number of regions in the Indo-Pacific Ocean (India, Japan, and Hawaii) and in the Mediterranean. The taxonomic description of P. nigra includes a striking smooth, black tunic and large size. However, there are at least two similar Phallusia species-P. philippinensis and P. fumigata-which also have dark black tunics and can be difficult to discern from P. nigra. The distribution of P. nigra broadly overlaps with P. philippinensis in the Indo-Pacific and P. fumigata in the Mediterranean. A morphological comparison of P. nigra from Japan, the Caribbean coast of Panama, and Brazil found that Atlantic and Pacific samples were different species and led us to investigate the range of P. nigra using morphological and molecular analyses. We sequenced 18S rDNA and cytochrome oxidase B of individual ascidians from the Red Sea, Greece, Singapore, Japan, Caribbean Panama, Florida, and Brazil. Our results show that identification of the disparate darkly pigmented species has been difficult, and that several reports of P. nigra are likely either P. fumigata or P. philippinensis. Here we include detailed taxonomic descriptions of the distinguishing features of these three species and sequences for molecular barcoding in an effort to have ranges and potential invasions corrected in the ascidian literature. PMID:25745100

  2. A global assembly line to cyanobactins

    PubMed Central

    Donia, Mohamed S.; Ravel, Jacques; Schmidt, Eric W.

    2009-01-01

    More than 100 cyclic peptides harboring heterocyclized residues are known from marine ascidians, sponges and different genera of cyanobacteria. Here, we report an assembly line responsible for the biosynthesis of these diverse peptides, now called cyanobactins, both in symbiotic and free-living cyanobacteria. By comparing five new cyanobactin biosynthetic clusters, we could produce the prenylated antitumor preclinical candidate, trunkamide, in E. coli culture using genetic engineering. PMID:18425112

  3. Territoriality and Conflict Avoidance Explain Asociality (Solitariness) of the Endosymbiotic Pea Crab Tunicotheres moseri.

    PubMed

    Ambrosio, Louis J; Baeza, J Antonio

    2016-01-01

    Host monopolization theory predicts symbiotic organisms inhabiting morphologically simple, relatively small and scarce hosts to live solitarily as a result of territorial behaviors. We tested this prediction with Tunicotheres moseri, an endosymbiotic crab dwelling in the atrial chamber of the morphologically simple, small, and relatively scarce ascidian Styela plicata. As predicted, natural populations of T. moseri inhabit ascidian hosts solitarily with greater frequency than expected by chance alone. Furthermore, laboratory experiments demonstrated that intruder crabs take significantly longer to colonize previously infected compared to uninfected hosts, indicating as expected, that resident crabs exhibit monopolization behaviors. While territoriality does occur, agonistic behaviors employed by T. moseri do not mirror the overt behaviors commonly reported for other territorial crustaceans. Documented double and triple cohabitations in the field coupled with laboratory observations demonstrating the almost invariable success of intruder crabs colonizing occupied hosts, suggest that territoriality is ineffective in completely explaining the solitary social habit of this species. Additional experiments showed that T. moseri juveniles and adults, when searching for ascidians use chemical cues to avoid hosts occupied by conspecifics. This conspecific avoidance behavior reported herein is a novel strategy most likely employed to preemptively resolve costly territorial conflicts. In general, this study supports predictions central to host monopolization theory, but also implies that alternative behavioral strategies (i.e., conflict avoidance) may be more important than originally thought in explaining the host use pattern of symbiotic organisms. PMID:26910474

  4. Territoriality and Conflict Avoidance Explain Asociality (Solitariness) of the Endosymbiotic Pea Crab Tunicotheres moseri

    PubMed Central

    Ambrosio, Louis J.; Baeza, J. Antonio

    2016-01-01

    Host monopolization theory predicts symbiotic organisms inhabiting morphologically simple, relatively small and scarce hosts to live solitarily as a result of territorial behaviors. We tested this prediction with Tunicotheres moseri, an endosymbiotic crab dwelling in the atrial chamber of the morphologically simple, small, and relatively scarce ascidian Styela plicata. As predicted, natural populations of T. moseri inhabit ascidian hosts solitarily with greater frequency than expected by chance alone. Furthermore, laboratory experiments demonstrated that intruder crabs take significantly longer to colonize previously infected compared to uninfected hosts, indicating as expected, that resident crabs exhibit monopolization behaviors. While territoriality does occur, agonistic behaviors employed by T. moseri do not mirror the overt behaviors commonly reported for other territorial crustaceans. Documented double and triple cohabitations in the field coupled with laboratory observations demonstrating the almost invariable success of intruder crabs colonizing occupied hosts, suggest that territoriality is ineffective in completely explaining the solitary social habit of this species. Additional experiments showed that T. moseri juveniles and adults, when searching for ascidians use chemical cues to avoid hosts occupied by conspecifics. This conspecific avoidance behavior reported herein is a novel strategy most likely employed to preemptively resolve costly territorial conflicts. In general, this study supports predictions central to host monopolization theory, but also implies that alternative behavioral strategies (i.e., conflict avoidance) may be more important than originally thought in explaining the host use pattern of symbiotic organisms. PMID:26910474

  5. Developmental genetics in primitive chordates.

    PubMed Central

    Sordino, P; Belluzzi, L; De Santis, R; Smith, W C

    2001-01-01

    Recent advances in the study of the genetics and genomics of urochordates testify to a renewed interest in this chordate subphylum, believed to be the most primitive extant chordate relatives of the vertebrates. In addition to their primitive nature, many features of their reproduction and early development make the urochordates ideal model chordates for developmental genetics. Many urochordates spawn large numbers of transparent and externally developing embryos on a daily basis. Additionally, the embryos have a defined and well-characterized cell lineage until the end of gastrulation. Furthermore, the genomes of the urochordates have been estimated to be only 5-10% of the size of the vertebrates and to have fewer genes and less genetic redundancy than vertebrates. Genetic screens, which are powerful tools for investigating developmental mechanisms, have recently become feasible due to new culturing techniques in ascidians. Because hermaphrodite ascidians are able to self-fertilize, recessive mutations can be detected in a single generation. Several recent studies have demonstrated the feasibility of applying modern genetic techniques to the study of ascidian biology. PMID:11604124

  6. Linking climate change and biological invasions: Ocean warming facilitates nonindigenous species invasions.

    PubMed

    Stachowicz, John J; Terwin, Jeffrey R; Whitlatch, Robert B; Osman, Richard W

    2002-11-26

    The spread of exotic species and climate change are among the most serious global environmental threats. Each independently causes considerable ecological damage, yet few data are available to assess whether changing climate might facilitate invasions by favoring introduced over native species. Here, we compare our long-term record of weekly sessile marine invertebrate recruitment with interannual variation in water temperature to assess the likely effect of climate change on the success and spread of introduced species. For the three most abundant introduced species of ascidian (sea squirt), the timing of the initiation of recruitment was strongly negatively correlated with winter water temperature, indicating that invaders arrived earlier in the season in years with warmer winters. Total recruitment of introduced species during the following summer also was positively correlated with winter water temperature. In contrast, the magnitude of native ascidian recruitment was negatively correlated with winter temperature (more recruitment in colder years) and the timing of native recruitment was unaffected. In manipulative laboratory experiments, two introduced compound ascidians grew faster than a native species, but only at temperatures near the maximum observed in summer. These data suggest that the greatest effects of climate change on biotic communities may be due to changing maximum and minimum temperatures rather than annual means. By giving introduced species an earlier start, and increasing the magnitude of their growth and recruitment relative to natives, global warming may facilitate a shift to dominance by nonnative species, accelerating the homogenization of the global biota. PMID:12422019

  7. Seasonal variability in the recruitment of macrofouling community in Kudankulam waters, east coast of India

    NASA Astrophysics Data System (ADS)

    Satheesh, S.; Godwin Wesley, S.

    2008-09-01

    The seasonal variability in fouling community recruitment on submerged artificial substratum was studied in Kudankulam coastal water, Gulf of Mannar, East coast of India for a period of two years, from May 2003 to April 2005. The results indicated that the fouling community recruitment occurred throughout the year with varying intensities. Barnacles, ascidians, polychaetes, bivalves and seaweeds were the major fouling groups observed from the test panels. Maximum fouling biomass of 9.17 g dm -2 was observed during August 2004 and a minimum value of 0.233 g dm -2 in February 2004. The biomass build-up on test panels was relatively high during the premonsoon season and low during the postmonsoon months. The number of barnacles settled on the panels varied from 1 to 4460 no. dm -2. The maximum percentage of the ascidian coverage (72%) on test panels was observed during March 2005. In general, July-December was the period of intense recruitment for barnacles and March-May was the period for ascidians.

  8. rRNA genes from the lower chordate Herdmania momus: structural similarity with higher eukaryotes.

    PubMed Central

    Degnan, B M; Yan, J; Hawkins, C J; Lavin, M F

    1990-01-01

    Ascidians, primitive chordates that have retained features of the likely progenitors to all vertebrates, are a useful model to study the evolutionary relationship of chordates to other animals. We have selected the well characterized ribosomal RNA (rRNA) genes to investigate this relationship, and we describe here the cloning and characterization of an entire ribosomal DNA (rDNA) tandem repeat unit from a lower chordate, the ascidian Herdmania momus. rDNA copy number and considerable sequence differences were observed between two H. momus populations. Comparison of rDNA primary sequence and rRNA secondary structures from H. momus with those from other well characterized organisms, demonstrated that the ascidians are more closely related to other chordates than invertebrates. The rDNA tandem repeat makes up a larger percentage (7%) of the genome of this animal than in other higher eukaryotes. The total length of the spacer and transcribed region in H. momus rDNA is small compared to most higher eukaryotes, being less than 8 kb, and the intergenic spacer region consists of smaller internal repeats. Comparative analysis of rDNA sequences has allowed the construction of secondary structures for the 18S, 5.8S and 26S rRNAs. Images PMID:2263465

  9. Recruitment Variability of Coral Reef Sessile Communities of the Far North Great Barrier Reef

    PubMed Central

    Luter, Heidi M.; Duckworth, Alan R.; Wolff, Carsten W.; Evans-Illidge, Elizabeth; Whalan, Steve

    2016-01-01

    One of the key components in assessing marine sessile organism demography is determining recruitment patterns to benthic habitats. An analysis of serially deployed recruitment tiles across depth (6 and 12 m), seasons (summer and winter) and space (meters to kilometres) was used to quantify recruitment assemblage structure (abundance and percent cover) of corals, sponges, ascidians, algae and other sessile organisms from the northern sector of the Great Barrier Reef (GBR). Polychaetes were most abundant on recruitment titles, reaching almost 50% of total recruitment, yet covered <5% of each tile. In contrast, mean abundances of sponges, ascidians, algae, and bryozoans combined was generally less than 20% of total recruitment, with percentage cover ranging between 15–30% per tile. Coral recruitment was very low, with <1 recruit per tile identified. A hierarchal analysis of variation over a range of spatial and temporal scales showed significant spatio-temporal variation in recruitment patterns, but the highest variability occurred at the lowest spatial scale examined (1 m—among tiles). Temporal variability in recruitment of both numbers of taxa and percentage cover was also evident across both summer and winter. Recruitment across depth varied for some taxonomic groups like algae, sponges and ascidians, with greatest differences in summer. This study presents some of the first data on benthic recruitment within the northern GBR and provides a greater understanding of population ecology for coral reefs. PMID:27049650

  10. Recruitment Variability of Coral Reef Sessile Communities of the Far North Great Barrier Reef.

    PubMed

    Luter, Heidi M; Duckworth, Alan R; Wolff, Carsten W; Evans-Illidge, Elizabeth; Whalan, Steve

    2016-01-01

    One of the key components in assessing marine sessile organism demography is determining recruitment patterns to benthic habitats. An analysis of serially deployed recruitment tiles across depth (6 and 12 m), seasons (summer and winter) and space (meters to kilometres) was used to quantify recruitment assemblage structure (abundance and percent cover) of corals, sponges, ascidians, algae and other sessile organisms from the northern sector of the Great Barrier Reef (GBR). Polychaetes were most abundant on recruitment titles, reaching almost 50% of total recruitment, yet covered <5% of each tile. In contrast, mean abundances of sponges, ascidians, algae, and bryozoans combined was generally less than 20% of total recruitment, with percentage cover ranging between 15-30% per tile. Coral recruitment was very low, with <1 recruit per tile identified. A hierarchal analysis of variation over a range of spatial and temporal scales showed significant spatio-temporal variation in recruitment patterns, but the highest variability occurred at the lowest spatial scale examined (1 m-among tiles). Temporal variability in recruitment of both numbers of taxa and percentage cover was also evident across both summer and winter. Recruitment across depth varied for some taxonomic groups like algae, sponges and ascidians, with greatest differences in summer. This study presents some of the first data on benthic recruitment within the northern GBR and provides a greater understanding of population ecology for coral reefs. PMID:27049650

  11. Regulation and evolution of cardiopharyngeal cell identity and behavior: insights from simple chordates.

    PubMed

    Kaplan, Nicole; Razy-Krajka, Florian; Christiaen, Lionel

    2015-06-01

    The vertebrate heart arises from distinct first and second heart fields. The latter also share a common origin with branchiomeric muscles in the pharyngeal mesoderm and transcription regulators, such as Nkx2-5, Tbx1 and Islet1. Despite significant progress, the complexity of vertebrate embryos has hindered the identification of multipotent cardiopharyngeal progenitors. Here, we summarize recent insights in cardiopharyngeal development gained from ascidian models, among the closest relatives to vertebrates. In a simplified cellular context, progressive fate specification of the ascidian cardiopharyngeal precursors presents striking similarities with their vertebrate counterparts. Multipotent cardiopharyngeal progenitors are primed to activate both the early cardiac and pharyngeal muscles programs, which segregate following asymmetric cells divisions as a result of regulatory cross-antagonisms involving Tbx1 and Nkx2-5 homologs. Activation of Ebf in pharyngeal muscle founder cells triggers both Myogenic Regulatory Factor-associated differentiation and Notch-mediated maintenance of an undifferentiated state in distinct precursors. Cross-species comparisons revealed the deep conservation of the cardiopharyngeal developmental sequence in spite of extreme genome sequence divergence, gene network rewiring and specific morphogenetic differences. Finally, analyses are beginning to uncover the influence of surrounding tissues in determining cardiopharyngeal cell identity and behavior. Thus, ascidian embryos offer a unique opportunity to study gene regulation and cell behaviors at the cellular level throughout cardiopharyngeal morphogenesis and evolution. PMID:25819888

  12. Effects of early recruits on temperate sessile marine community composition depend on other species recruiting at the time.

    PubMed

    Sams, Michael A; Keough, Michael J

    2013-09-01

    In many environments recruitment of dispersive propagules (e.g. seeds, spores and larvae) can vary from situations when particular taxa recruit in relative isolation to times when they recruit simultaneously with other, functionally quite different taxa. Differences in the identity and density of recruiting taxa can have important consequences on community structure, but it is still not clear how the effects of individual taxa on communities are modified when they recruit together with other species. Using an experimental approach we compared early development of a temperate marine sessile community after the recruitment of mixtures of botryllid ascidians and barnacles to that when barnacles or botryllid ascidians recruited alone. Communities exposed to recruitment of botryllid ascidians in isolation differed from those that received barnacles, a mixture of botryllids and barnacles or no recruitment in 2-week-old communities. These early differences were driven by higher abundances of the species that were present as initial recruits in experimental treatments. After 2 months communities also differed between barnacle and mixed recruitment treatments but not mixed and botryllid or botryllid and barnacle treatments. These differences were not directly due to differences in the abundances of our manipulated taxa but occurred because of two abundant arborescent bryozoans, Bugula dentata, which occupied more space in communities that initially received mixed recruitment than in those that received barnacle or no recruitment, and Zoobotryon verticillatum, which occupied more space in communities that initially received only barnacle recruitment than those that initially received botryllid or mixed recruitment. These effects did not persist, and communities did not differ after 6 months. These results suggest that, more generally, species may influence community dynamics differently when they recruit alongside other species than when they recruit in relative isolation

  13. [Evolutional principles of homology in regulatory genes of myogenesis].

    PubMed

    Ozerniuk, I D; Miuge, N S

    2012-01-01

    Analysis of early steps in muscular system development of invertebrates and vertebrates shows that early steps of myogenesis are regulated by genes-orthologs mainly belonging to two families, Pax and bHLH. In the majority of the following organisms, muscles formation (steps of determination and the earliest steps of myogenesis) is regulated by genes orthologs Pax3 which belong to the family Pax: nematodes (Caenorhabditis elegans, Pristionchus pacificus), insects (Drosophila melanogaster), echinoderms (Strongylocentrotus purpuratus), sea squirts (Ciona intestinalis, Holocynthia roretzi), fishes (Danio rerio), amphibians (Xenopus laevis), birds, and mammals (mouse, rat). The nematode C. elegans is an exception since formation of its muscles in this period is regulated by homeobox gene Pal-1 belonging to the family Caudal. The sea squirt C. intestinalis is also an exception because the earliest steps of development involved in further muscle formation are accompanied by activation of the gene CiSna (snail) (gene family basic Zinc finger). The next steps of myogenesis in all analyzed species are regulated by genes orthologs belonging to the family of transcriptional factors bHLH. They along with genes Pax3 are characterized by a high extent of homology in all studied groups of animals. PMID:22988754

  14. Recent Advances in Drug Discovery from South African Marine Invertebrates.

    PubMed

    Davies-Coleman, Michael T; Veale, Clinton G L

    2015-10-01

    Recent developments in marine drug discovery from three South African marine invertebrates, the tube worm Cephalodiscus gilchristi, the ascidian Lissoclinum sp. and the sponge Topsentia pachastrelloides, are presented. Recent reports of the bioactivity and synthesis of the anti-cancer secondary metabolites cephalostatin and mandelalides (from C. gilchristi and Lissoclinum sp., respectively) and various analogues are presented. The threat of drug-resistant pathogens, e.g., methicillin-resistant Staphylococcus aureus (MRSA), is assuming greater global significance, and medicinal chemistry strategies to exploit the potent MRSA PK inhibition, first revealed by two marine secondary metabolites, cis-3,4-dihydrohamacanthin B and bromodeoxytopsentin from T. pachastrelloides, are compared. PMID:26473891

  15. Recent Advances on the Total Syntheses of Communesin Alkaloids and Perophoramidine.

    PubMed

    Trost, Barry M; Osipov, Maksim

    2015-11-01

    The communesin alkaloids are a diverse family of Penicillium-derived alkaloids. Their caged-polycyclic structure and intriguing biological profiles have made these natural products attractive targets for total synthesis. Similarly, the ascidian-derived alkaloid, perophoramidine, is structurally related to the communesins and has also become a popular target for total synthesis. This review serves to summarize the many elegant approaches that have been developed to access the communesin alkaloids and perophoramidine. Likewise, strategies to access the communesin ring system are reviewed. PMID:26353936

  16. Genetic Regulatory Networks in Embryogenesis and Evolution

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The article introduces a series of papers that were originally presented at a workshop titled Genetic Regulatory Network in Embryogenesis and Evaluation. Contents include the following: evolution of cleavage programs in relationship to axial specification and body plan evolution, changes in cell lineage specification elucidate evolutionary relations in spiralia, axial patterning in the leech: developmental mechanisms and evolutionary implications, hox genes in arthropod development and evolution, heterochronic genes in development and evolution, a common theme for LIM homeobox gene function across phylogeny, and mechanisms of specification in ascidian embryos.

  17. Periclimenaeus denticulodigitus sp. nov. (Crustacea: Decapoda: Palaemonidae: Pontoniinae), from Heron Island, Queensland, Australia.

    PubMed

    Bruce, A J

    2014-01-01

    An unusual species of the genus Periclimenaeus Borradaile, 1915 (Crustacea: Decapoda: Palaemonidae Pontoniinae) from Heron Island, Queensland, Australia, collected by Dr Niel Bruce in 1979, is described and illustrated. Periclimenaeus denticulodigitus sp. nov., an ascidian associate was collected from coral reef at 7.0 m and presents some interesting new features. It increases to 17 the number of Periclimenaeus known from Heron Island, Queensland, and to 28 the number of species known from Australia. The new species has the second pereiopod fingers minutely denticulate and unique to the genus. PMID:24872280

  18. Prochloron--a status report

    NASA Technical Reports Server (NTRS)

    Lewin, R. A.

    1984-01-01

    Prochloron is a genus of prokaryotic algae with photosynthetic pigments like those of chlorophytes. Prochlorophytes are almost invariably found associated as symbionts with marine protochordates (didemnid ascidians), and so far none has been successfully grown in sustained culture away from in host. Based on materials collected from nature, information of various sorts (biochemical, physiological, cytological and fine-structural) has been obtained, indicating many resemblances (and probably close phylogenetic affinities) between prochlorophytes and cyanophytes. Nevertheless they are distinguished by certain unique combinations of characters. Some of the data support the symbiogenesis theory for the origin of green-plant chloroplasts. Other possibilities are briefly discussed.

  19. Intracellular coagulation inhibits the extraction of proteins from Prochloron

    NASA Technical Reports Server (NTRS)

    Fall, R.; Lewin, R. A.; Fall, L. R.

    1983-01-01

    Protein extraction from the prokaryotic alga Prochloron LP (isolated from the ascidian host Lissoclinum patella) was complicated by an irreversible loss of cell fragility in the isolated algae. Accompanying this phenomenon, which is termed intracellular coagulation, was a redistribution of thylakoids around the cell periphery, a loss of photosynthetic O2 production, and a drastic decrease in the extractability of cell proteins. Procedures are described for the successful preparation and transport of cell extracts yielding the enzymes glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase as well as other soluble proteins.

  20. Looking at both sides of the invasion: patterns of colonization in the violet tunicate Botrylloides violaceus.

    PubMed

    Bock, D G; Zhan, A; Lejeusne, C; MacIsaac, H J; Cristescu, M E

    2011-02-01

    Understanding the ecological and evolutionary forces that shape the genetic structure of invasive populations and facilitate their expansion across a large spectrum of environments is critical for the prediction of spread and management of ongoing invasions. Here, we study the dynamics of postestablishment colonization in the colonial ascidian Botrylloides violaceus, a notorious marine invader. After its initial introduction from the Northwest Pacific, B. violaceus spread rapidly along the Pacific and Atlantic coasts of North America, impacting both aquaculture facilities and natural ecosystems. We compare genetic diversity and patterns of gene flow among 25 populations (N=679) from the West and East coasts, and evaluate the contribution of sexual vs. asexual reproduction to this species' invasion success using data from the mitochondrial cytochrome c oxidase subunit I (COI) gene and 13 nuclear polymorphic microsatellite loci. Our results reveal contrasting patterns of spread in the coastal waters of North America. While the West coast was colonized by noncontiguous (long-distance) dispersal, the East coast invasion appears to have occurred through contiguous (stepping-stone) spread. Molecular data further indicate that although dispersal in colonial ascidians is predominantly achieved through sexually produced propagules, aquaculture practices such as high-pressure washing can facilitate fragmentation and potentially exacerbate infestations and spread via asexual propagules. The results presented here suggest that caution should be used against the general assumption that all invasions, even within a single species, exhibit similar patterns of colonization, as highly contrasting dynamics may transpire in different invaded ranges. PMID:21199029

  1. Migration of germline progenitor cells is directed by sphingosine-1-phosphate signalling in a basal chordate.

    PubMed

    Kassmer, Susannah H; Rodriguez, Delany; Langenbacher, Adam D; Bui, Connor; De Tomaso, Anthony W

    2015-01-01

    The colonial ascidian Botryllus schlosseri continuously regenerates entire bodies in an asexual budding process. The germ line of the newly developing bodies is derived from migrating germ cell precursors, but the signals governing this homing process are unknown. Here we show that germ cell precursors can be prospectively isolated based on expression of aldehyde dehydrogenase and integrin alpha-6, and that these cells express germ cell markers such as vasa, pumilio and piwi, as well as sphingosine-1-phosphate receptor. In vitro, sphingosine-1-phosphate (S1P) stimulates migration of germ cells, which depends on integrin alpha-6 activity. In vivo, S1P signalling is essential for homing of germ cells to newly developing bodies. S1P is generated by sphingosine kinase in the developing germ cell niche and degraded by lipid phosphate phosphatase in somatic tissues. These results demonstrate a previously unknown role of the S1P signalling pathway in germ cell migration in the ascidian Botryllus schlosseri. PMID:26456232

  2. IPE 7

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A description is given of the collection and treatment of samples of Prochloron cells. The cells of Prochloron were obtained and prepared in the following way. Colonies of the symbiotic host, the giant didemnid ascidian Lissoclinum patella, were collected at low-tide level on reef-flat sand between Kamori Island and Koror, Palau, Western Caroline Islands. The animal colonies were taken, immersed in sea water, to an 8,000-litre holding tank and kept with constantly running sea water at 30 deg. Individual colonies were picked clean of contaminants, rinsed in sea water buffered with 40 nM or 100 mM Tris buffer at pH 8.4, and squeezed by hand to express the algal cells from the cloacal atria. The algae were received in about an equal volume of the same buffered sea water; this neutralized the acids liberated by the bruised ascidians and thereby maintained the Ph high enough to keep the algal cells green. The Prochloron cells were washed twice with buffered sea water and concentrated by centrifugation at about 50 g for 90 seconds. Microscopic examination revealed that contamination by animal host cells or bacteria was negligible (much less than 1%).

  3. The enigmatic life history of the symbiotic crab Tunicotheres moseri (Crustacea, Brachyura, Pinnotheridae): implications for its mating system and population structure.

    PubMed

    Hernández, J E; Bolaños, J A; Palazón, J L; Hernández, G; Lira, C; Baeza, J Antonio

    2012-12-01

    Resource-monopolization theory predicts the adoption of a solitary habit in species using scarce, discrete, and small refuges. Life-history theory suggests that temporarily stable parental dwellings favor extended parental care in species that brood embryos. We tested these two predictions with the symbiotic crab Tunicotheres moseri. This species exhibits abbreviated development and inhabits the atrial chamber of the scarce, structurally simple, long-lived, and relatively small ascidian Phalusia nigra in the Caribbean. These host characteristics should favor a solitary habit and extended parental care (EPC) in T. moseri. As predicted, males and females of T. moseri inhabited ascidians solitarily with greater frequency than expected by chance alone. The male-female association pattern and reverse sexual dimorphism (males < females) additionally suggests a promiscuous "pure-search" mating system in T. moseri. Also in agreement with theoretical considerations, T. moseri displays EPC; in addition to embryos, females naturally retain larval stages, megalopae, and juveniles within their brooding pouches. This is the first record of EPC in a symbiotic crab and the second confirmed record of EPC in a marine brachyuran crab. This study supports predictions central to resource-monopolization and life-history theories. PMID:23264474

  4. Migration of germline progenitor cells is directed by sphingosine-1-phosphate signalling in a basal chordate

    PubMed Central

    Kassmer, Susannah H.; Rodriguez, Delany; Langenbacher, Adam D.; Bui, Connor; De Tomaso, Anthony W.

    2015-01-01

    The colonial ascidian Botryllus schlosseri continuously regenerates entire bodies in an asexual budding process. The germ line of the newly developing bodies is derived from migrating germ cell precursors, but the signals governing this homing process are unknown. Here we show that germ cell precursors can be prospectively isolated based on expression of aldehyde dehydrogenase and integrin alpha-6, and that these cells express germ cell markers such as vasa, pumilio and piwi, as well as sphingosine-1-phosphate receptor. In vitro, sphingosine-1-phosphate (S1P) stimulates migration of germ cells, which depends on integrin alpha-6 activity. In vivo, S1P signalling is essential for homing of germ cells to newly developing bodies. S1P is generated by sphingosine kinase in the developing germ cell niche and degraded by lipid phosphate phosphatase in somatic tissues. These results demonstrate a previously unknown role of the S1P signalling pathway in germ cell migration in the ascidian Botryllus schlosseri. PMID:26456232

  5. Expression of pro-opiomelanocortin (POMC) in the cerebral ganglion and ovary of a protochordate.

    PubMed

    Masini, M A; Sturla, M; Gallinelli, A; Candiani, S; Facchinetti, F; Pestarino, M

    1998-01-01

    The distribution of neurones expressing POMC mRNA in the cerebral ganglion of the protochordate ascidian, Styela plicata, was investigated using a non-radioactive in situ hybridization technique. Nerve cell bodies of mono and bipolar types expressing POMC mRNA, were observed mainly in the outer layer of the ganglion. Discrete groups of neurones containing POMC mRNA were also localized in the inner portion of the ganglion, and few small monopolar perykaria expressing POMC mRNA were visible at the emergence of the main nerve trunks. POMC mRNA labeling was also found at level of the cytoplasm of previtellogenic and vitellogenic oocytes, and of follicular cells. Our results demonstrate the expression of one or more genes in the cerebral ganglion and ovary, that may be similar to one or more regions of the mammalian POMC gene. Therefore POMC-related molecules seem to be involved in neuromodulatory pathways and regulatory mechanisms of the oogenesis of ascidians. PMID:9786167

  6. Influence of submersion season on the development of test panel biofouling communities in a tropical coast

    NASA Astrophysics Data System (ADS)

    Satheesh, S.; Wesley, S. G.

    2011-08-01

    The effect of test panel submersion season on the colonization of biofouling communities in a tropical coast revealed that the effects of panel submersion time should be taken into consideration for modelling fouling community recruitment dynamics in coastal systems or during the field trials of antifouling coatings. Wooden test panels fitted onto a raft were submerged during pre-monsoon, monsoon and post-monsoon seasons for the development of the biofouling community. Results showed considerable variation in the colonization of fouling communities on test panels submerged during different seasons. Barnacles, tubeworms, ascidians and seaweeds were the major fouling communities that colonized the test panels. The total biomass of the fouling communities that settled on the post-monsoon season panels varied from the initial value of 2.72 g dm -2 to a maximum of 44.5 g dm -2. On the panels submerged during monsoon season, the total biomass of fouling communities varied between 0.78 g dm -2 and 69.9 g dm -2. The total fouling biomass on the pre-monsoon season panels varied between 2.95 and 33.5 g dm -2. Barnacles were the initial colonizers on the panels submerged during pre-monsoon and post-monsoon seasons. Soft-bodied organisms such as ascidians dominated the monsoon season-initiated panel series during the initial period.

  7. Comparative biology of cAMP-induced germinal vesicle breakdown in marine invertebrate oocytes.

    PubMed

    Deguchi, Ryusaku; Takeda, Noriyo; Stricker, Stephen A

    2011-01-01

    During maturation, oocytes must undergo a process of nuclear disassembly, or "germinal vesicle breakdown" (GVBD), that is regulated by signaling pathways involving cyclic AMP (cAMP). In vertebrate and starfish oocytes, cAMP elevation typically prevents GVBD. Alternatively, increased concentrations of intra-oocytic cAMP trigger, rather than inhibit, GVBD in several groups of marine invertebrates. To integrate what is known about the stimulation of GVBD by intra-oocytic cAMP, this article reviews published data for ascidian, bivalve, brittle star, jellyfish, and nemertean oocytes. The bulk of the review concentrates on the three most intensively analyzed groups known to display cAMP-induced GVBD-nemerteans, ascidians, and jellyfish. In addition, this synopsis also presents some previously unpublished findings regarding the stimulatory effects of intra-oocytic cAMP on GVBD in jellyfish and the annelid worm Pseudopotamilla occelata. Finally, factors that may account for the currently known distribution of cAMP-induced GVBD across animal groups are discussed. PMID:21774023

  8. Genomic view of the evolution of the complement system

    PubMed Central

    Kimura, Ayuko

    2006-01-01

    The recent accumulation of genomic information of many representative animals has made it possible to trace the evolution of the complement system based on the presence or absence of each complement gene in the analyzed genomes. Genome information from a few mammals, chicken, clawed frog, a few bony fish, sea squirt, fruit fly, nematoda and sea anemone indicate that bony fish and higher vertebrates share practically the same set of complement genes. This suggests that most of the gene duplications that played an essential role in establishing the mammalian complement system had occurred by the time of the teleost/mammalian divergence around 500 million years ago (MYA). Members of most complement gene families are also present in ascidians, although they do not show a one-to-one correspondence to their counterparts in higher vertebrates, indicating that the gene duplications of each gene family occurred independently in vertebrates and ascidians. The C3 and factor B genes, but probably not the other complement genes, are present in the genome of the cnidaria and some protostomes, indicating that the origin of the central part of the complement system was established more than 1,000 MYA. PMID:16896831

  9. Early Chordate Origin of the Vertebrate Integrin αI Domains

    PubMed Central

    Chouhan, Bhanupratap Singh; Käpylä, Jarmo; Denessiouk, Konstantin; Denesyuk, Alexander; Heino, Jyrki; Johnson, Mark S.

    2014-01-01

    Half of the 18 human integrins α subunits have an inserted αI domain yet none have been observed in species that have diverged prior to the appearance of the urochordates (ascidians). The urochordate integrin αI domains are not human orthologues but paralogues, but orthologues of human αI domains extend throughout later-diverging vertebrates and are observed in the bony fish with duplicate isoforms. Here, we report evidence for orthologues of human integrins with αI domains in the agnathostomes (jawless vertebrates) and later diverging species. Sequence comparisons, phylogenetic analyses and molecular modeling show that one nearly full-length sequence from lamprey and two additional fragments include the entire integrin αI domain region, have the hallmarks of collagen-binding integrin αI domains, and we show that the corresponding recombinant proteins recognize the collagen GFOGER motifs in a metal dependent manner, unlike the α1I domain of the ascidian C. intestinalis. The presence of a functional collagen receptor integrin αI domain supports the origin of orthologues of the human integrins with αI domains prior to the earliest diverging extant vertebrates, a domain that has been conserved and diversified throughout the vertebrate lineage. PMID:25409021

  10. Natural Variation of Model Mutant Phenotypes in Ciona intestinalis

    PubMed Central

    Brown, Euan R.; Leccia, Nicola I.; Squarzoni, Paola; Tarallo, Raffaella; Alfano, Christian; Caputi, Luigi; D'Ambrosio, Palmira; Daniele, Paola; D'Aniello, Enrico; D'Aniello, Salvatore; Maiella, Sylvie; Miraglia, Valentina; Russo, Monia Teresa; Sorrenti, Gerarda; Branno, Margherita; Cariello, Lucio; Cirino, Paola; Locascio, Annamaria; Spagnuolo, Antonietta; Zanetti, Laura; Ristoratore, Filomena

    2008-01-01

    Background The study of ascidians (Chordata, Tunicata) has made a considerable contribution to our understanding of the origin and evolution of basal chordates. To provide further information to support forward genetics in Ciona intestinalis, we used a combination of natural variation and neutral population genetics as an approach for the systematic identification of new mutations. In addition to the significance of developmental variation for phenotype-driven studies, this approach can encompass important implications in evolutionary and population biology. Methodology/Principal Findings Here, we report a preliminary survey for naturally occurring mutations in three geographically interconnected populations of C. intestinalis. The influence of historical, geographical and environmental factors on the distribution of abnormal phenotypes was assessed by means of 12 microsatellites. We identified 37 possible mutant loci with stereotyped defects in embryonic development that segregate in a way typical of recessive alleles. Local populations were found to differ in genetic organization and frequency distribution of phenotypic classes. Conclusions/Significance Natural genetic polymorphism of C. intestinalis constitutes a valuable source of phenotypes for studying embryonic development in ascidians. Correlating genetic structure and the occurrence of abnormal phenotypes is a crucial focus for understanding the selective forces that shape natural finite populations, and may provide insights of great importance into the evolutionary mechanisms that generate animal diversity. PMID:18523552

  11. Origin and evolution of the parasitic cyclopoid copepods.

    PubMed

    Ho, J S

    1994-12-01

    Six of the 10 recognised families of the order Cyclopoida are parasitic, with 4 of them occurring on marine invertebrates and the remaining 2 on freshwater gastropods and fishes, respectively. A cladistic analysis of the 10 families indicates that evolution of parasitism occurred twice in the history of the cyclopoids. The first attempt was made by the marine epibenthic ancestors seeking food and shelter in sessile tunicates--the ascidians. This event led to the evolution of 2 ascidicolous families: Archinotodelphyidae and Notodelphyidae. The descendant of this lineage had also invaded the mantle cavity of marine bivalve molluscs, eventually leading to the evolution of the Mantridae. The second attempt for the parasitic mode of life was launched by the ancestor which was the sister group of the ancestral cyclopoids--the most successful family of freshwater copepods. This ancestral stock, while living in the coastal zone, split into 2 groups: one group stayed behind in the ocean and colonised again the ascidians; the other groups invaded freshwater and evolved into the fish-parasitising Lernaeidae and the gastropod-parasitising Ozmanidae. PMID:7729982

  12. Vanadium-Binding Ability of Nucleoside Diphosphate Kinase from the Vanadium-Rich Fan Worm, Pseudopotamilla occelata.

    PubMed

    Yamaguchi, Nobuo; Yoshinaga, Masafumi; Kamino, Kei; Ueki, Tatsuya

    2016-06-01

    Polychaete fan worms and ascidians accumulate high levels of vanadium ions. Several vanadiumbinding proteins, known as vanabins, have been found in ascidians. However, no vanadium-binding factors have been isolated from the fan worm. In the present study, we sought to identify vanadiumbinding proteins in the branchial crown of the fan worm using immobilized metal ion affinity chromatography. A nucleoside diphosphate kinase (NDK) homolog was isolated and determined to be a vanadium-binding protein. Kinase activity of the NDK homologue, PoNDK, was suppressed by the addition of V(IV), but was unaffected by V(V). The effect of V(IV) on PoNDK precedes its activation by Mg(II). This is the first report to describe the relationship between NDK and V(IV). PoNDK is located in the epidermis of the branchial crown, and its distribution is very similar to that of vanadium. These results suggest that PoNDK is associated with vanadium accumulation and metabolism in P. occelata. PMID:27268980

  13. Transmission and Scanning Electron Microscopy of the Accessory Cells and Chorion During Development of Ciona intestinalis Type B Embryos and the Impact of Their Removal on Cell Morphology.

    PubMed

    Thompson, Helen; Shimeld, Sebastian M

    2015-06-01

    Spawned ascidian oocytes are surrounded by a membrane called the chorion (or vitelline coat) and associated with two populations of maternally-supplied cells. Outside the chorion are follicle cells, which may affect the buoyancy of eggs. Inside the chorion are test cells, which during oogenesis provision the egg and which after fertilisation contribute to the larval tunic. The structure of maternal cells may vary between species. The model ascidian Ciona intestinalis has been recently split into two species, currently named type A and type B. The ultrastructure of extraembryonic cells and structures from type A embryos has been reported. Here we describe the ultrastructure of follicle and test cells from C. intestinalis type B embryos. Test cells are about 5 µm in diameter and line the inside of the chorion of developing embryos in a dense sheet. Follicle cells are large (> 100 µm long) and spike-shaped, with many large vesicles. Terminal electron dense granules are found towards the tips of spikes, adjacent to cytoplasm containing numerous small electron dense bodies connected by filaments. These are probably vesicles containing material for the terminal granules. Removal of maternal structures and cells just after fertilisation, as commonly used in many experiments manipulating C. intestinalis development, has been reported to affect embryonic patterning. We examined the impact of this on embryonic ectoderm cells by scanning electron microscopy. Cells of embryos that developed without maternal structures still developed cilia, but had indistinct cell boundaries and a more flattened appearance than those that developed within the chorion. PMID:26003975

  14. High quality draft genome sequence of the slightly halophilic bacterium Halomonas zhanjiangensis type strain JSM 078169(T) (DSM 21076(T)) from a sea urchin in southern China.

    PubMed

    Zhou, Yu; Li, Rui; Gao, Xiao-Yang; Lapidus, Alla; Han, James; Haynes, Matthew; Lobos, Elizabeth; Huntemann, Marcel; Pati, Amrita; Ivanova, Natalia N; Rohde, Manfred; Mavromatis, Konstantinos; Tindall, Brian J; Markowitz, Victor; Woyke, Tanja; Klenk, Hans-Peter; Kyrpides, Nikos C; Li, Wen-Jun

    2014-06-15

    Halomonas zhanjiangensis Chen et al. 2009 is a member of the genus Halomonas, family Halomonadaceae, class Gammaproteobacteria. Representatives of the genus Halomonas are a group of halophilic bacteria often isolated from salty environments. The type strain H. zhanjiangensis JSM 078169(T) was isolated from a sea urchin (Hemicentrotus pulcherrimus) collected from the South China Sea. The genome of strain JSM 078169(T) is the fourteenth sequenced genome in the genus Halomonas and the fifteenth in the family Halomonadaceae. The other thirteen genomes from the genus Halomonas are H. halocynthiae, H. venusta, H. alkaliphila, H. lutea, H. anticariensis, H. jeotgali, H. titanicae, H. desiderata, H. smyrnensis, H. salifodinae, H. boliviensis, H. elongata and H stevensii. Here, we describe the features of strain JSM 078169(T), together with the complete genome sequence and annotation from a culture of DSM 21076(T). The 4,060,520 bp long draft genome consists of 17 scaffolds with the 3,659 protein-coding and 80 RNA genes and is a part of Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes (KMG) project. PMID:25197480

  15. Incremental evolution of the neural crest, neural crest cells and neural crest-derived skeletal tissues

    PubMed Central

    Hall, Brian K; Gillis, J Andrew

    2013-01-01

    Urochordates (ascidians) have recently supplanted cephalochordates (amphioxus) as the extant sister taxon of vertebrates. Given that urochordates possess migratory cells that have been classified as ‘neural crest-like’– and that cephalochordates lack such cells – this phylogenetic hypothesis may have significant implications with respect to the origin of the neural crest and neural crest-derived skeletal tissues in vertebrates. We present an overview of the genes and gene regulatory network associated with specification of the neural crest in vertebrates. We then use these molecular data – alongside cell behaviour, cell fate and embryonic context – to assess putative antecedents (latent homologues) of the neural crest or neural crest cells in ascidians and cephalochordates. Ascidian migratory mesenchymal cells – non-pigment-forming trunk lateral line cells and pigment-forming ‘neural crest-like cells’ (NCLC) – are unlikely latent neural crest cell homologues. Rather, Snail-expressing cells at the neural plate of border of urochordates and cephalochordates likely represent the extent of neural crest elaboration in non-vertebrate chordates. We also review evidence for the evolutionary origin of two neural crest-derived skeletal tissues – cartilage and dentine. Dentine is a bona fide vertebrate novelty, and dentine-secreting odontoblasts represent a cell type that is exclusively derived from the neural crest. Cartilage, on the other hand, likely has a much deeper origin within the Metazoa. The mesodermally derived cellular cartilages of some protostome invertebrates are much more similar to vertebrate cartilage than is the acellular ‘cartilage-like’ tissue in cephalochordate pharyngeal arches. Cartilage, therefore, is not a vertebrate novelty, and a well-developed chondrogenic program was most likely co-opted from mesoderm to the neural crest along the vertebrate stem. We conclude that the neural crest is a vertebrate novelty, but that neural

  16. Data on four apoptosis-related genes in the colonial tunicate Botryllus schlosseri.

    PubMed

    Franchi, Nicola; Ballin, Francesca; Manni, Lucia; Schiavon, Filippo; Ballarin, Loriano

    2016-09-01

    The data described are related to the article entitled "Recurrent phagocytosis-induced apoptosis in the cyclical generation change of the compound ascidian Botryllus schlosseri" (Franchi et al., 2016) [1]. Four apoptosis-related genes, showing high similarity with mammalian Bax (a member of the Bcl-2 protein family), AIF1 (apoptosis-inducing factor-1), PARP1 (poly ADP ribose polymerase-1) and IAP7 (inhibitor of apoptosis-7) were identified from the analysis of the trascriptome of B. schlosseri. They were named BsBax, BsAIF1, BsPARP1 and BsIAP7. Here, their deduced amino acid sequence were compared with known sequences of orthologous genes from other deuterostome species together with a study of their identity/similarity. PMID:27294183

  17. An Early Cambrian tunicate from China.

    PubMed

    Shu, D G; Chen, L; Han, J; Zhang, X L

    2001-05-24

    Like the Burgess Shales of Canada, the Chengjiang Lagerstätte from the Lower Cambrian of China is renowned for the detailed preservation as fossils of delicate, soft-bodied creatures, providing an insight into the Cambrian explosion. The fossils of possible hemichordate chordates and vertebrates have attracted particular attention. Tunicates, or urochordates, comprise the most basal chordate clade, and details of their evolution could be important in understanding the sequence of character acquisition that led to the emergence of chordates and vertebrates. However, definitive fossils of tunicates from the Cambrian are scarce or debatable. Here we report a probable tunicate Cheungkongella ancestralis from the Chengjiang fauna. It resembles the extant ascidian tunicate genus Styela whose morphology could be useful in understanding the origin of the vertebrates. PMID:11373678

  18. β-catenin-driven binary cell fate decisions in animal development.

    PubMed

    Bertrand, Vincent

    2016-01-01

    The Wnt/β-catenin pathway plays key roles during animal development. In several species, β-catenin is used in a reiterative manner to regulate cell fate diversification between daughter cells following division. This binary cell fate specification mechanism has been observed in animals that belong to very diverse phyla: the nematode Caenorhabditis elegans, the annelid Platynereis, and the ascidian Ciona. It may also play a role in the regulation of several stem cell lineages in vertebrates. While the molecular mechanism behind this binary cell fate switch is not fully understood, it appears that both secreted Wnt ligands and asymmetric cortical factors contribute to the generation of the difference in nuclear β-catenin levels between daughter cells. β-Catenin then cooperates with lineage specific transcription factors to induce the expression of novel sets of transcription factors at each round of divisions, thereby diversifying cell fate. For further resources related to this article, please visit the WIREs website. PMID:26952169

  19. An organismal perspective on C. intestinalis development, origins and diversification

    PubMed Central

    Kourakis, Matthew J; Smith, William C

    2015-01-01

    The ascidian Ciona intestinalis, commonly known as a ‘sea squirt’, has become an important model for embryological studies, offering a simple blueprint for chordate development. As a model organism, it offers the following: a small, compact genome; a free swimming larva with only about 2600 cells; and an embryogenesis that unfolds according to a predictable program of cell division. Moreover, recent phylogenies reveal that C. intestinalis occupies a privileged branch in the tree of life: it is our nearest invertebrate relative. Here, we provide an organismal perspective of C. intestinalis, highlighting aspects of its life history and habitat—from its brief journey as a larva to its radical metamorphosis into adult form—and relate these features to its utility as a laboratory model. DOI: http://dx.doi.org/10.7554/eLife.06024.001 PMID:25807088

  20. Ciona as a Simple Chordate Model for Heart Development and Regeneration

    PubMed Central

    Anderson, Heather Evans; Christiaen, Lionel

    2016-01-01

    Cardiac cell specification and the genetic determinants that govern this process are highly conserved among Chordates. Recent studies have established the importance of evolutionarily-conserved mechanisms in the study of congenital heart defects and disease, as well as cardiac regeneration. As a basal Chordate, the Ciona model system presents a simple scaffold that recapitulates the basic blueprint of cardiac development in Chordates. Here we will focus on the development and cellular structure of the heart of the ascidian Ciona as compared to other Chordates, principally vertebrates. Comparison of the Ciona model system to heart development in other Chordates presents great potential for dissecting the genetic mechanisms that underlie congenital heart defects and disease at the cellular level and might provide additional insight into potential pathways for therapeutic cardiac regeneration.

  1. Developmental Control of Cell-Cycle Compensation Provides a Switch for Patterned Mitosis at the Onset of Chordate Neurulation.

    PubMed

    Ogura, Yosuke; Sasakura, Yasunori

    2016-04-18

    During neurulation of chordate ascidians, the 11th mitotic division within the epidermal layer shows a posterior-to-anterior wave that is precisely coordinated with the unidirectional progression of the morphogenetic movement. Here we show that the first sign of this patterned mitosis is an asynchronous anterior-to-posterior S-phase length and that mitotic synchrony is reestablished by a compensatory asynchronous G2-phase length. Live imaging combined with genetic experiments demonstrated that compensatory G2-phase regulation requires transcriptional activation of the G2/M regulator cdc25 by the patterning genes GATA and AP-2. The downregulation of GATA and AP-2 at the onset of neurulation leads to loss of compensatory G2-phase regulation and promotes the transition to patterned mitosis. We propose that such developmentally regulated cell-cycle compensation provides an abrupt switch to spatially patterned mitosis in order to achieve the coordination between mitotic timing and morphogenesis. PMID:27093084

  2. Evaluation of the sea anemone Anthothoe albocincta as an augmentative biocontrol agent for biofouling on artificial structures.

    PubMed

    Atalah, Javier; Bennett, Holly; Hopkins, Grant A; Forrest, Barrie M

    2013-01-01

    Augmentative biocontrol, defined as the use of indigenous natural enemies to control pest populations, has not been explored extensively in marine systems. This study tested the potential of the anemone Anthothoe albocincta as a biocontrol agent for biofouling on submerged artificial structures. Biofouling biomass was negatively related to anemone cover. Treatments with high anemone cover (>35%) led to significant changes in biofouling assemblages compared to controls. Taxa that contributed to these changes differed among sites, but included reductions in cover of problematic fouling organisms, such as solitary ascidians and bryozoans. In laboratory trials, A. albocincta substantially prevented the settlement of larvae of the bryozoan Bugula neritina when exposed to three levels of larval dose, suggesting predation as an important biocontrol mechanism, in addition to space pre-emption. This study demonstrated that augmentative biocontrol using anemones has the potential to reduce biofouling on marine artificial structures, although considerable further work is required to refine this tool before its application. PMID:23682610

  3. Cyanobactins from Cyanobacteria: Current Genetic and Chemical State of Knowledge

    PubMed Central

    Martins, Joana; Vasconcelos, Vitor

    2015-01-01

    Cyanobacteria are considered to be one of the most promising sources of new, natural products. Apart from non-ribosomal peptides and polyketides, ribosomally synthesized and post-translationally modified peptides (RiPPs) are one of the leading groups of bioactive compounds produced by cyanobacteria. Among these, cyanobactins have sparked attention due to their interesting bioactivities and for their potential to be prospective candidates in the development of drugs. It is assumed that the primary source of cyanobactins is cyanobacteria, although these compounds have also been isolated from marine animals such as ascidians, sponges and mollusks. The aim of this review is to update the current knowledge of cyanobactins, recognized as being produced by cyanobacteria, and to emphasize their genetic clusters and chemical structures as well as their bioactivities, ecological roles and biotechnological potential. PMID:26580631

  4. Diversity of Nonribosomal Peptide Synthetase Genes in the Microbial Metagenomes of Marine Sponges

    PubMed Central

    Pimentel-Elardo, Sheila Marie; Grozdanov, Lubomir; Proksch, Sebastian; Hentschel, Ute

    2012-01-01

    Genomic mining revealed one major nonribosomal peptide synthetase (NRPS) phylogenetic cluster in 12 marine sponge species, one ascidian, an actinobacterial isolate and seawater. Phylogenetic analysis predicts its taxonomic affiliation to the actinomycetes and hydroxy-phenyl-glycine as a likely substrate. Additionally, a phylogenetically distinct NRPS gene cluster was discovered in the microbial metagenome of the sponge Aplysina aerophoba, which shows highest similarities to NRPS genes that were previously assigned, by ways of single cell genomics, to a Chloroflexi sponge symbiont. Genomic mining studies such as the one presented here for NRPS genes, contribute to on-going efforts to characterize the genomic potential of sponge-associated microbiota for secondary metabolite biosynthesis. PMID:22822366

  5. Cryptic speciation or global spread? The case of a cosmopolitan marine invertebrate with limited dispersal capabilities.

    PubMed

    R, Pérez-Portela; V, Arranz; M, Rius; X, Turon

    2013-01-01

    The existence of globally-distributed species with low dispersal capabilities is a paradox that has been explained as a result of human-mediated transport and by hidden diversity in the form of unrecognized cryptic species. Both factors are not mutually exclusive, but relatively few studies have demonstrated the presence of both. Here we analyse the genetic patterns of the colonial ascidian Diplosoma listerianum, a species nowadays distributed globally. The study of a fragment of a mitochondrial gene in localities worldwide revealed the existence of multiple cryptic species. In addition, we found a complex geographic structure and multiple clades occurred in sympatry. One of the species showed strong population structure irrespective of geographical distances, which is coherent with stochastic dispersal linked to human transport. The present study shows the complexity of discerning the role of cryptic diversity from human-driven range shifts worldwide, as well as disentangling the effects of natural and artificial dispersal. PMID:24217373

  6. Cryptic speciation or global spread? The case of a cosmopolitan marine invertebrate with limited dispersal capabilities

    PubMed Central

    R., Pérez-Portela; V., Arranz; M., Rius; X., Turon

    2013-01-01

    The existence of globally-distributed species with low dispersal capabilities is a paradox that has been explained as a result of human-mediated transport and by hidden diversity in the form of unrecognized cryptic species. Both factors are not mutually exclusive, but relatively few studies have demonstrated the presence of both. Here we analyse the genetic patterns of the colonial ascidian Diplosoma listerianum, a species nowadays distributed globally. The study of a fragment of a mitochondrial gene in localities worldwide revealed the existence of multiple cryptic species. In addition, we found a complex geographic structure and multiple clades occurred in sympatry. One of the species showed strong population structure irrespective of geographical distances, which is coherent with stochastic dispersal linked to human transport. The present study shows the complexity of discerning the role of cryptic diversity from human-driven range shifts worldwide, as well as disentangling the effects of natural and artificial dispersal. PMID:24217373

  7. Diversity of nonribosomal peptide synthetase genes in the microbial metagenomes of marine sponges.

    PubMed

    Pimentel-Elardo, Sheila Marie; Grozdanov, Lubomir; Proksch, Sebastian; Hentschel, Ute

    2012-06-01

    Genomic mining revealed one major nonribosomal peptide synthetase (NRPS) phylogenetic cluster in 12 marine sponge species, one ascidian, an actinobacterial isolate and seawater. Phylogenetic analysis predicts its taxonomic affiliation to the actinomycetes and hydroxy-phenyl-glycine as a likely substrate. Additionally, a phylogenetically distinct NRPS gene cluster was discovered in the microbial metagenome of the sponge Aplysina aerophoba, which shows highest similarities to NRPS genes that were previously assigned, by ways of single cell genomics, to a Chloroflexi sponge symbiont. Genomic mining studies such as the one presented here for NRPS genes, contribute to on-going efforts to characterize the genomic potential of sponge-associated microbiota for secondary metabolite biosynthesis. PMID:22822366

  8. Clinical marine toxicology: a European perspective for clinical toxicologists and poison centers.

    PubMed

    Schmitt, Corinne; De Haro, Luc

    2013-08-01

    Clinical marine toxicology is a rapidly changing area. Many of the new discoveries reported every year in Europe involve ecological disturbances--including global warming--that have induced modifications in the chorology, behavior, and toxicity of many species of venomous or poisonous aquatic life including algae, ascidians, fish and shellfish. These changes have raised a number of public issues associated, e.g., poisoning after ingestion of contaminated seafood, envenomation by fish stings, and exposure to harmful microorganism blooms. The purpose of this review of medical and scientific literature in marine toxicology is to highlight the growing challenges induced by ecological disturbances that confront clinical toxicologists during the everyday job in the European Poison Centers. PMID:23917333

  9. Vessel generator noise as a settlement cue for marine biofouling species.

    PubMed

    McDonald, J I; Wilkens, S L; Stanley, J A; Jeffs, A G

    2014-01-01

    Underwater noise is increasing globally, largely due to increased vessel numbers and international ocean trade. Vessels are also a major vector for translocation of non-indigenous marine species which can have serious implications for biosecurity. The possibility that underwater noise from fishing vessels may promote settlement of biofouling on hulls was investigated for the ascidian Ciona intestinalis. Spatial differences in biofouling appear to be correlated with spatial differences in the intensity and frequency of the noise emitted by the vessel's generator. This correlation was confirmed in laboratory experiments where C. intestinalis larvae showed significantly faster settlement and metamorphosis when exposed to the underwater noise produced by the vessel generator. Larval survival rates were also significantly higher in treatments exposed to vessel generator noise. Enhanced settlement attributable to vessel generator noise may indicate that vessels not only provide a suitable fouling substratum, but vessels running generators may be attracting larvae and enhancing their survival and growth. PMID:24866988

  10. Novel aspects of glypican glycobiology.

    PubMed

    Fransson, L-A; Belting, M; Cheng, F; Jönsson, M; Mani, K; Sandgren, S

    2004-05-01

    Mutations in glypican genes cause dysmorphic and overgrowth syndromes in men and mice, abnormal development in flies and worms, and defective gastrulation in zebrafish and ascidians. All glypican core proteins share a characteristic pattern of 14 conserved cysteine residues. Upstream from the C-terminal membrane anchorage are 3-4 heparan sulfate attachment sites. Cysteines in glypican-1 can become nitrosylated by nitric oxide in a copper-dependent reaction. When glypican-1 is exposed to ascorbate, nitric oxide is released and participates in deaminative cleavage of heparan sulfate at sites where the glucosamines have a free amino group. This process takes place while glypican-1 recycles via a nonclassical, caveolin-1-associated route. Glypicans are involved in growth factor signalling and transport, e.g. of polyamines. Cargo can be unloaded from heparan sulfate by nitric oxide-dependent degradation. How glypican and its degradation products and the cargo exit from the recycling route is an enigma. PMID:15112050

  11. Inhibitory effect of N,N-didesmethylgrossularine-1 on inflammatory cytokine production in lipopolysaccharide-stimulated RAW 264.7 cells.

    PubMed

    Oda, Taiko; Lee, Jong-Soo; Sato, Yuta; Kabe, Yasuaki; Sakamoto, Satoshi; Handa, Hiroshi; Mangindaan, Remy E P; Namikoshi, Michio

    2009-01-01

    N,N-Didesmethylgrossularine-1 (DDMG-1), a compound with a rare alpha-carboline structure, was isolated from an Indonesian ascidian Polycarpa aurata as responsible for the observed inhibitory activity against TNF-alpha production in lipopolysaccharide-stimulated murine macrophage-like RAW264.7 cells. DDMG-1 inhibited the mRNA level of mTNF-alpha, IkappaB-alpha degradation, and binding of NF-kappaB to the target DNA site in LPS-stimulated RAW 264.7 cells. Moreover, DDMG-1 had an inhibitory effect on the production of IL-8, which is produced in CD14(+)-THP-1 cells stimulated by LPS. DDMG-1 is thus a promising drug candidate lead compound for the treatment of chronic inflammatory diseases, such as rheumatoid arthritis. PMID:20098600

  12. Inhibitory Effect of N,N-Didesmethylgrossularine-1 on Inflammatory Cytokine Production in Lipopolysaccharide-Stimulated RAW 264.7 Cells

    PubMed Central

    Oda, Taiko; Lee, Jong-Soo; Sato, Yuta; Kabe, Yasuaki; Sakamoto, Satoshi; Handa, Hiroshi; Mangindaan, Remy E. P.; Namikoshi, Michio

    2009-01-01

    N,N-Didesmethylgrossularine-1 (DDMG-1), a compound with a rare α-carboline structure, was isolated from an Indonesian ascidian Polycarpa aurata as responsible for the observed inhibitory activity against TNF-α production in lipopolysaccharide-stimulated murine macrophage-like RAW264.7 cells. DDMG-1 inhibited the mRNA level of mTNF-α, IκB-α degradation, and binding of NF-κB to the target DNA site in LPS-stimulated RAW 264.7 cells. Moreover, DDMG-1 had an inhibitory effect on the production of IL-8, which is produced in CD14+-THP-1 cells stimulated by LPS. DDMG-1 is thus a promising drug candidate lead compound for the treatment of chronic inflammatory diseases, such as rheumatoid arthritis. PMID:20098600

  13. Physical association between a novel plasma-membrane structure and centrosome orients cell division.

    PubMed

    Negishi, Takefumi; Miyazaki, Naoyuki; Murata, Kazuyoshi; Yasuo, Hitoyoshi; Ueno, Naoto

    2016-01-01

    In the last mitotic division of the epidermal lineage in the ascidian embryo, the cells divide stereotypically along the anterior-posterior axis. During interphase, we found that a unique membrane structure invaginates from the posterior to the centre of the cell, in a microtubule-dependent manner. The invagination projects toward centrioles on the apical side of the nucleus and associates with one of them. Further, a cilium forms on the posterior side of the cell and its basal body remains associated with the invagination. A laser ablation experiment suggests that the invagination is under tensile force and promotes the posterior positioning of the centrosome. Finally, we showed that the orientation of the invaginations is coupled with the polarized dynamics of centrosome movements and the orientation of cell division. Based on these findings, we propose a model whereby this novel membrane structure orchestrates centrosome positioning and thus the orientation of cell division axis. PMID:27502556

  14. Clinical Marine Toxicology: A European Perspective for Clinical Toxicologists and Poison Centers

    PubMed Central

    Schmitt, Corinne; de Haro, Luc

    2013-01-01

    Clinical marine toxicology is a rapidly changing area. Many of the new discoveries reported every year in Europe involve ecological disturbances—including global warming—that have induced modifications in the chorology, behavior, and toxicity of many species of venomous or poisonous aquatic life including algae, ascidians, fish and shellfish. These changes have raised a number of public issues associated, e.g., poisoning after ingestion of contaminated seafood, envenomation by fish stings, and exposure to harmful microorganism blooms. The purpose of this review of medical and scientific literature in marine toxicology is to highlight the growing challenges induced by ecological disturbances that confront clinical toxicologists during the everyday job in the European Poison Centers. PMID:23917333

  15. Phallusiasterols A and B: Two New Sulfated Sterols from the Mediterranean Tunicate Phallusia fumigata and Their Effects as Modulators of the PXR Receptor

    PubMed Central

    Imperatore, Concetta; D’Aniello, Filomena; Aiello, Anna; Fiorucci, Stefano; D’Amore, Claudio; Sepe, Valentina; Menna, Marialuisa

    2014-01-01

    Purification of the apolar extracts of the marine ascidian Phallusia fumigata, afforded two new sulfated sterols, phallusiasterols A (1) and B (2). The structures of the new compounds have been elucidated using mass spectrometry and NMR experiments. The effects of phallusiasterols A and B as modulators of pregnane-X-receptor (PXR) have been investigated. These studies revealed that phallusiasterol A induces PXR transactivation in HepG2 cells and stimulates the expression of the PXR target genes CYP3A4 and MDR1 in the same cell line. Molecular docking calculations suggested the theoretical binding mode of phallusiasterol A with hPXR and revealed that phallusiasterol A fitted well in the LBD of PXR. PMID:24705503

  16. Cyanobactins from Cyanobacteria: Current Genetic and Chemical State of Knowledge.

    PubMed

    Martins, Joana; Vasconcelos, Vitor

    2015-11-01

    Cyanobacteria are considered to be one of the most promising sources of new, natural products. Apart from non-ribosomal peptides and polyketides, ribosomally synthesized and post-translationally modified peptides (RiPPs) are one of the leading groups of bioactive compounds produced by cyanobacteria. Among these, cyanobactins have sparked attention due to their interesting bioactivities and for their potential to be prospective candidates in the development of drugs. It is assumed that the primary source of cyanobactins is cyanobacteria, although these compounds have also been isolated from marine animals such as ascidians, sponges and mollusks. The aim of this review is to update the current knowledge of cyanobactins, recognized as being produced by cyanobacteria, and to emphasize their genetic clusters and chemical structures as well as their bioactivities, ecological roles and biotechnological potential. PMID:26580631

  17. An organismal perspective on C. intestinalis development, origins and diversification.

    PubMed

    Kourakis, Matthew J; Smith, William C

    2015-01-01

    The ascidian Ciona intestinalis, commonly known as a 'sea squirt', has become an important model for embryological studies, offering a simple blueprint for chordate development. As a model organism, it offers the following: a small, compact genome; a free swimming larva with only about 2600 cells; and an embryogenesis that unfolds according to a predictable program of cell division. Moreover, recent phylogenies reveal that C. intestinalis occupies a privileged branch in the tree of life: it is our nearest invertebrate relative. Here, we provide an organismal perspective of C. intestinalis, highlighting aspects of its life history and habitat-from its brief journey as a larva to its radical metamorphosis into adult form-and relate these features to its utility as a laboratory model. PMID:25807088

  18. Sperm motility parameters and spermatozoa morphometric characterization in marine species: a study of swimmer and sessile species.

    PubMed

    Gallego, V; Pérez, L; Asturiano, J F; Yoshida, M

    2014-09-15

    The biodiversity of marine ecosystems is diverse and a high number of species coexist side by side. However, despite the fact that most of these species share a common fertilization strategy, a high variability in terms of the size, shape, and motion of spermatozoa can be found. In this study, we have analyzed both the sperm motion parameters and the spermatozoa morphometric features of two swimmer (pufferfish and European eel) and two sessile (sea urchin and ascidian) marine species. The most important differences in the sperm motion parameters were registered in the swimming period. Sessile species sperm displayed notably higher values than swimmer species sperm. In addition, the sperm motilities and velocities of the swimmer species decreased sharply once the sperm was activated, whereas the sessile species were able to maintain their initial values for a long time. These results are linked directly to the species-specific lifestyles. Although sessile organisms, which show limited or no movement, need sperm with a capacity to swim for long distances to find the oocytes, swimmer organisms can move toward the female and release gametes near it, and therefore the spermatozoa does not need to swim for such a long time. At the same time, sperm morphology is related to sperm motion parameters, and in this study an in-depth morphometric analysis of ascidian, sea urchin, and pufferfish spermatozoa, using computer-assisted sperm analysis software, has been carried out for the first time. A huge variability in shapes, sizes, and structures of the studied species was found using electron microscopy. PMID:25016411

  19. Redeployment of germ layers related TFs shows regionalized expression during two non-embryonic developments.

    PubMed

    Ricci, Lorenzo; Cabrera, Fabien; Lotito, Sonia; Tiozzo, Stefano

    2016-08-01

    In all non-vertebrate metazoan phyla, species that evolved non-embryonic developmental pathways as means of propagation or regeneration can be found. In this context, new bodies arise through asexual reproduction processes (such as budding) or whole body regeneration, that lack the familiar temporal and spatial cues classically associated with embryogenesis, like maternal determinants, or gastrulation. The molecular mechanisms underlying those non-embryonic developments (i.e., regeneration and asexual reproduction), and their relationship to those deployed during embryogenesis are poorly understood. We have addressed this question in the colonial ascidian Botryllus schlosseri, which undergoes an asexual reproductive process via palleal budding (PB), as well as a whole body regeneration by vascular budding (VB). We identified early regenerative structures during VB and then followed the fate of differentiating tissues during both non-embryonic developments (PB and VB) by monitoring the expression of genes known to play key functions in germ layer specification with well conserved expression patterns in solitary ascidian embryogenesis. The expression patterns of FoxA1, GATAa, GATAb, Otx, Bra, Gsc and Tbx2/3 were analysed during both PB and VB. We found that the majority of these transcription factors were expressed during both non-embryonic developmental processes, revealing a regionalization of the palleal and vascular buds. Knockdown of GATAa by siRNA in palleal buds confirmed that preventing the correct development of one of these regions blocks further tissue specification. Our results indicate that during both normal and injury-induced budding, a similar alternative developmental program operates via early commitment of epithelial regions. PMID:27208394

  20. Evolution of anterior Hox regulatory elements among chordates

    PubMed Central

    2011-01-01

    Background The Hox family of transcription factors has a fundamental role in segmentation pathways and axial patterning of embryonic development and their clustered organization is linked with the regulatory mechanisms governing their coordinated expression along embryonic axes. Among chordates, of particular interest are the Hox paralogous genes in groups 1-4 since their expression is coupled to the control of regional identity in the anterior nervous system, where the highest structural diversity is observed. Results To investigate the degree of conservation in cis-regulatory components that form the basis of Hox expression in the anterior nervous system, we have used assays for transcriptional activity in ascidians and vertebrates to compare and contrast regulatory potential. We identified four regulatory sequences located near the CiHox1, CiHox2 and CiHox4 genes of the ascidian Ciona intestinalis which direct neural specific domains of expression. Using functional assays in Ciona and vertebrate embryos in combination with sequence analyses of enhancer fragments located in similar positions adjacent to Hox paralogy group genes, we compared the activity of these four Ciona cis-elements with a series of neural specific enhancers from the amphioxus Hox1-3 genes and from mouse Hox paralogous groups 1-4. Conclusions This analysis revealed that Kreisler and Krox20 dependent enhancers critical in segmental regulation of the hindbrain appear to be specific for the vertebrate lineage. In contrast, neural enhancers that function as Hox response elements through the action of Hox/Pbx binding motifs have been conserved during chordate evolution. The functional assays reveal that these Hox response cis-elements are recognized by the regulatory components of different and extant species. Together, our results indicate that during chordate evolution, cis-elements dependent upon Hox/Pbx regulatory complexes, are responsible for key aspects of segmental Hox expression in neural

  1. Tunicate mitogenomics and phylogenetics: peculiarities of the Herdmania momus mitochondrial genome and support for the new chordate phylogeny

    PubMed Central

    2009-01-01

    Background Tunicates represent a key metazoan group as the sister-group of vertebrates within chordates. The six complete mitochondrial genomes available so far for tunicates have revealed distinctive features. Extensive gene rearrangements and particularly high evolutionary rates have been evidenced with regard to other chordates. This peculiar evolutionary dynamics has hampered the reconstruction of tunicate phylogenetic relationships within chordates based on mitogenomic data. Results In order to further understand the atypical evolutionary dynamics of the mitochondrial genome of tunicates, we determined the complete sequence of the solitary ascidian Herdmania momus. This genome from a stolidobranch ascidian presents the typical tunicate gene content with 13 protein-coding genes, 2 rRNAs and 24 tRNAs which are all encoded on the same strand. However, it also presents a novel gene arrangement, highlighting the extreme plasticity of gene order observed in tunicate mitochondrial genomes. Probabilistic phylogenetic inferences were conducted on the concatenation of the 13 mitochondrial protein-coding genes from representatives of major metazoan phyla. We show that whereas standard homogeneous amino acid models support an artefactual sister position of tunicates relative to all other bilaterians, the CAT and CAT+BP site- and time-heterogeneous mixture models place tunicates as the sister-group of vertebrates within monophyletic chordates. Moreover, the reference phylogeny indicates that tunicate mitochondrial genomes have experienced a drastic acceleration in their evolutionary rate that equally affects protein-coding and ribosomal-RNA genes. Conclusion This is the first mitogenomic study supporting the new chordate phylogeny revealed by recent phylogenomic analyses. It illustrates the beneficial effects of an increased taxon sampling coupled with the use of more realistic amino acid substitution models for the reconstruction of animal phylogeny. PMID:19922605

  2. Calcium at fertilization and in early development

    PubMed Central

    Whitaker, Michael

    2012-01-01

    Fertilization calcium waves are introduced and the evidence from which we can infer general mechanisms of these waves is presented. The two main classes of hypothesis put forward to explain the generation of the fertilization calcium wave are set out and it is concluded that initiation of the fertilization calcium wave can be most generally explained in inverterbrates by a mechanism in which an activating substance enters the egg from the sperm on sperm-egg fusion, activating the egg by stimulating phospholipase C activation through a src family kinase pathway and in mammals by the diffusion of a sperm-specific phospholipase C from sperm to egg on sperm-egg fusion. The fertilization calcium wave is then set into the context of cell cycle control and the mechanism of repetitive calcium spiking in mammalian eggs is investigated. Evidence that calcium signals control cell division in early embryos is reviewed, and it is concluded that calcium signals are essential at all three stages of cell division in early embryos. Evidence that phosphoinositide signalling pathways control the resumption of meiosis during oocyte maturation is considered. It is concluded on balance that the evidence points to a need for phosphoinositide/calcium signalling during resumption of meiosis. Changes to the calcium signalling machinery occur during meiosis to enable the production of a calcium wave in the mature oocyte when it is fertilized; evidence that the shape and structure of the endoplasmic reticulum alters dynamically during maturation and after fertilization is reviewed and the link between ER dynamics and the cytoskeleton is discussed. There is evidence that calcium signalling plays a key part in the development of patterning in early embryos. Morphogenesis in ascidian, frog and zebrafish embryos is briefly described to provide the developmental context in which calcium signals act. Intracellular calcium waves that may play a role in axis formation in ascidian are discussed

  3. Climate change and glacier retreat drive shifts in an Antarctic benthic ecosystem.

    PubMed

    Sahade, Ricardo; Lagger, Cristian; Torre, Luciana; Momo, Fernando; Monien, Patrick; Schloss, Irene; Barnes, David K A; Servetto, Natalia; Tarantelli, Soledad; Tatián, Marcos; Zamboni, Nadia; Abele, Doris

    2015-11-01

    The Antarctic Peninsula (AP) is one of the three places on Earth that registered the most intense warming in the last 50 years, almost five times the global mean. This warming has strongly affected the cryosphere, causing the largest ice-shelf collapses ever observed and the retreat of 87% of glaciers. Ecosystem responses, although increasingly predicted, have been mainly reported for pelagic systems. However, and despite most Antarctic species being benthic, responses in the Antarctic benthos have been detected in only a few species, and major effects at assemblage level are unknown. This is probably due to the scarcity of baselines against which to assess change. We performed repeat surveys of coastal benthos in 1994, 1998, and 2010, analyzing community structure and environmental variables at King George Island, Antarctica. We report a marked shift in an Antarctic benthic community that can be linked to ongoing climate change. However, rather than temperature as the primary factor, we highlight the resulting increased sediment runoff, triggered by glacier retreat, as the potential causal factor. The sudden shift from a "filter feeders-ascidian domination" to a "mixed assemblage" suggests that thresholds (for example, of tolerable sedimentation) and alternative equilibrium states, depending on the reversibility of the changes, could be possible traits of this ecosystem. Sedimentation processes will be increasing under the current scenario of glacier retreat, and attention needs to be paid to its effects along the AP. PMID:26702429

  4. Total Synthesis and Biological Evaluation of (+)- and (–)-Bisanthraquinone Antibiotic BE-43472B and Related Compounds

    PubMed Central

    Nicolaou, K. C.; Becker, Jochen; Lim, Yee Hwee; Lemire, Alexandre; Neubauer, Thomas; Montero, Ana

    2009-01-01

    The bisanthraquinone antibiotic BE-43472B [(+)-1] was isolated by Rowley and coworkers from a streptomycete strain found in a green algae associated with the ascidian Ecteinascidia turbinata and has shown promising antibacterial activity against clinically derived isolates of methicillin-susceptible, methicillin-resistant, and tetracyclin-resistant Staphylococcus aureus (MSSA, MRSA, and TRSA, respectively), and vancomycin-resistant Enterococcus faecalis (VRE). Described herein is the first total synthesis of both enantiomers of this bisanthraquinone antibiotic, the determination of its absolute configuration, as well as the biological evaluation of these and related compounds. The developed synthesis relies on a highly efficient cascade sequence involving an intermolecular Diels–Alder reaction between diene (R)-61 and dienophile 55 followed by an intramolecular nucleophilic aromatic ipso substitution. Late stage transformations included a remarkable photochemical α,β-epoxyketone rearrangement [80 → (+)-1]. Interestingly, the unnatural enantiomer [(–)-1] of antibiotic BE-43472B exhibited comparable antibacterial properties to those of the natural enantiomer [(+)-1]. PMID:19778008

  5. A workflow to process 3D+time microscopy images of developing organisms and reconstruct their cell lineage

    PubMed Central

    Faure, Emmanuel; Savy, Thierry; Rizzi, Barbara; Melani, Camilo; Stašová, Olga; Fabrèges, Dimitri; Špir, Róbert; Hammons, Mark; Čúnderlík, Róbert; Recher, Gaëlle; Lombardot, Benoît; Duloquin, Louise; Colin, Ingrid; Kollár, Jozef; Desnoulez, Sophie; Affaticati, Pierre; Maury, Benoît; Boyreau, Adeline; Nief, Jean-Yves; Calvat, Pascal; Vernier, Philippe; Frain, Monique; Lutfalla, Georges; Kergosien, Yannick; Suret, Pierre; Remešíková, Mariana; Doursat, René; Sarti, Alessandro; Mikula, Karol; Peyriéras, Nadine; Bourgine, Paul

    2016-01-01

    The quantitative and systematic analysis of embryonic cell dynamics from in vivo 3D+time image data sets is a major challenge at the forefront of developmental biology. Despite recent breakthroughs in the microscopy imaging of living systems, producing an accurate cell lineage tree for any developing organism remains a difficult task. We present here the BioEmergences workflow integrating all reconstruction steps from image acquisition and processing to the interactive visualization of reconstructed data. Original mathematical methods and algorithms underlie image filtering, nucleus centre detection, nucleus and membrane segmentation, and cell tracking. They are demonstrated on zebrafish, ascidian and sea urchin embryos with stained nuclei and membranes. Subsequent validation and annotations are carried out using Mov-IT, a custom-made graphical interface. Compared with eight other software tools, our workflow achieved the best lineage score. Delivered in standalone or web service mode, BioEmergences and Mov-IT offer a unique set of tools for in silico experimental embryology. PMID:26912388

  6. A workflow to process 3D+time microscopy images of developing organisms and reconstruct their cell lineage.

    PubMed

    Faure, Emmanuel; Savy, Thierry; Rizzi, Barbara; Melani, Camilo; Stašová, Olga; Fabrèges, Dimitri; Špir, Róbert; Hammons, Mark; Čúnderlík, Róbert; Recher, Gaëlle; Lombardot, Benoît; Duloquin, Louise; Colin, Ingrid; Kollár, Jozef; Desnoulez, Sophie; Affaticati, Pierre; Maury, Benoît; Boyreau, Adeline; Nief, Jean-Yves; Calvat, Pascal; Vernier, Philippe; Frain, Monique; Lutfalla, Georges; Kergosien, Yannick; Suret, Pierre; Remešíková, Mariana; Doursat, René; Sarti, Alessandro; Mikula, Karol; Peyriéras, Nadine; Bourgine, Paul

    2016-01-01

    The quantitative and systematic analysis of embryonic cell dynamics from in vivo 3D+time image data sets is a major challenge at the forefront of developmental biology. Despite recent breakthroughs in the microscopy imaging of living systems, producing an accurate cell lineage tree for any developing organism remains a difficult task. We present here the BioEmergences workflow integrating all reconstruction steps from image acquisition and processing to the interactive visualization of reconstructed data. Original mathematical methods and algorithms underlie image filtering, nucleus centre detection, nucleus and membrane segmentation, and cell tracking. They are demonstrated on zebrafish, ascidian and sea urchin embryos with stained nuclei and membranes. Subsequent validation and annotations are carried out using Mov-IT, a custom-made graphical interface. Compared with eight other software tools, our workflow achieved the best lineage score. Delivered in standalone or web service mode, BioEmergences and Mov-IT offer a unique set of tools for in silico experimental embryology. PMID:26912388

  7. Surrounding tissues canalize motile cardiopharyngeal progenitors towards collective polarity and directed migration.

    PubMed

    Gline, Stephanie; Kaplan, Nicole; Bernadskaya, Yelena; Abdu, Yusuff; Christiaen, Lionel

    2015-02-01

    Collectively migrating cells maintain group polarity and interpret external cues to reach their destination. The cardiogenic progenitors (also known as trunk ventral cells, TVCs) of the ascidian Ciona intestinalis provide a simple chordate model with which to study collective migration. Bilateral pairs of associated TVCs undergo a stereotyped polarized migration away from the tail towards the ventral trunk, arguably constituting the simplest possible example of directed collective migration. To identify tissues contributing to TVC polarity and migration, we quantified the contact between TVCs and surrounding tissues, and blocked the secretory pathway in a tissue-specific manner. Even though TVCs normally migrate as an invariably determined leader-trailer polarized pair of adherent cells, they are capable of migrating individually, albeit a shorter distance and with altered morphology. The mesenchyme contacts newborn TVCs and contributes to robust specification of the trailer but appears to have only minor effects on directed migration. The notochord does not contact the TVCs but contributes to the onset of migration. The trunk endoderm first contacts the leader TVC, then 'encases' both migrating cells and provides the inputs maintaining leader-trailer polarity. Migrating TVCs adhere to the epidermis and need this contact for their cohesion. These phenomenological studies reveal that inherently motile cardiopharyngeal progenitors are channeled into stereotyped behaviors by interactions with surrounding tissues. PMID:25564651

  8. Effects of metals and sediment particle size on the species composition of the epifauna of Pinna bicolor near a lead smelter, Spencer Gulf, South Australia

    NASA Astrophysics Data System (ADS)

    Ward, Trevor J.; Young, Peter C.

    1984-01-01

    Pinna bicolor (Mollusca: Pelecypoda) were transplanted between four sites near a lead smelter. The species composition of their epifauna (sessile and mobile) was examined in relation to characteristics of both sediments and seston at the sites. Seventy-two taxa were distinguished in the epifaunal community. Substantial differences were found in the short-term sensitivity of some of the species to concentrations of Cd, Pb and Zn in sediments and to sediment particle size. The short-term sensitivity of many species to metals or sediment particle size explained their long-term distribution pattern. Twenty-three taxa were identified as significantly characterizing the faunal differences. Of these, eleven (four molluscs, four bryozoans, two barnacles and one ascidian) were affected by both sediment metal concentration and particle size, and eight (four molluscs, one bryozoan, one polychaete, one hydroid and one barnacle) were affected by metal contamination but not particle size. Of all fauna examined, the Bryozoa were the most metal-sensitive. Four species, Smittina raigii (Bryozoa), Galeolaria sp. 1 (Polychaeta), Epopella simplex (Cirripedia) and Monia ione (Pelecypoda) were identified by their short- and long-term sensitivity to metal contamination, and absence of sensitivity to sediment particle size, as suitable species for monitoring the effects of metal contamination on the epifauna. The implications of the results for toxicity-testing are discussed.

  9. Desiccation as a mitigation tool to manage biofouling risks: trials on temperate taxa to elucidate factors influencing mortality rates.

    PubMed

    Hopkins, Grant A; Prince, Madeleine; Cahill, Patrick L; Fletcher, Lauren M; Atalah, Javier

    2016-01-01

    The desiccation tolerance of biofouling taxa (adults and early life-stages) was determined under both controlled and 'realistic' field conditions. Adults of the ascidian Ciona spp. died within 24 h. Mortality in the adult blue mussel Mytilus galloprovincialis occurred within 11 d under controlled conditions, compared with 7 d when held outside. The Pacific oyster Crassostrea gigas was the most desiccation-tolerant taxon tested (up to 34 d under controlled conditions). Biofouling orientated to direct sunlight showed faster mortality rates for all the taxa tested. Mortality in Mytilus juveniles took up to 24 h, compared with 8 h for Ciona, with greater survival at the higher temperature (18.5°C) and humidity (~95% RH) treatment combination. This study demonstrated that desiccation can be an effective mitigation method for a broad range of fouling taxa, especially their early life-stages. Further work is necessary to assess risks from other high-risk species such as algae and cyst forming species. PMID:26691450

  10. The cult of amphioxus in German Darwinism; or, our gelatinous ancestors in Naples' blue and balmy bay.

    PubMed

    Hopwood, Nick

    2015-01-01

    Biologists having rediscovered amphioxus, also known as the lancelet or Branchiostoma, it is time to reassess its place in early Darwinist debates over vertebrate origins. While the advent of the ascidian-amphioxus theory and challenges from various competitors have been, documented, this article offers a richer account of the public appeal of amphioxus as a primitive ancestor. The focus is on how the 'German Darwin' Ernst Haeckel persuaded general magazine and newspaper readers to revere this "flesh of our flesh and blood of our blood", and especially on Das neue Laienbrevier des Haeckelismus (The new lay breviary of Haeckelism) by Moritz Reymond with cartoons by Fritz Steub. From the late 1870s these successful little books of verse introduced the Neapolitan discoveries that made the animal's name and satirized Haeckel's rise as high priest of its cult. One song is reproduced and translated here, with a contemporary "imitation" by the Canadian palaeontologist Edward John Chapman, and extracts from others. Predating the American "It's a long way from amphioxus" by decades, these rhymes dramatize neglected 'species politics' of Darwinism and highlight the roles of humour in negotiating evolution. PMID:26013195

  11. Megalodicopia hians in the Monterey submarine canyon: Distribution, larval development, and culture

    NASA Astrophysics Data System (ADS)

    Havenhand, Jon. N.; Matsumoto, George I.; Seidel, Ed

    2006-02-01

    The exclusively deep-sea ascidian family Octacnemidae comprises several genera in which the oral siphon has hypertrophied to form two large lips which create an "oral hood" capable of capturing motile prey. Megalodicopia hians is typical of this carnivorous family and has been reported to prey upon small epibenthic crustaceans. Distribution of M. hians in the Monterey Canyon system (36°45'N, 122°00'W) (California) was determined with remotely operated vehicles. M. hians was found sparsely to depths of at least 3800 m throughout the canyon; however, abundance was greatest within the oxygen-minimum zone (400-800 m). Eggs, sperm, and recently fertilized embryos were obtained repeatedly from adults returned to the laboratory in vivo, indicating that this species free-spawns routinely. Overall egg diameter (ovum plus chorion, plus follicle cells) was 175-190 μm—considerably smaller than previously reported for this species. Embryonic development at temperature and oxygen concentrations equivalent to the oxygen-minimum zone was 2-4 d and, embryos gave rise to typical phlebobranch "simple" tadpole larvae. Larval period was extremely variable, and settlement/metamorphosis occurred up to 3 months post-hatching. These results are discussed within the context of settlement-site selection and fertilization ecology of the species.

  12. A Protein Involved in the Assembly of an Extracellular Calcium Storage Matrix*

    PubMed Central

    Glazer, Lilah; Shechter, Assaf; Tom, Moshe; Yudkovski, Yana; Weil, Simy; Aflalo, Eliahu David; Pamuru, Ramachandra Reddy; Khalaila, Isam; Bentov, Shmuel; Berman, Amir; Sagi, Amir

    2010-01-01

    Gastroliths, the calcium storage organs of crustaceans, consist of chitin-protein-mineral complexes in which the mineral component is stabilized amorphous calcium carbonate. To date, only three proteins, GAP 65, gastrolith matrix protein (GAMP), and orchestin, have been identified in gastroliths. Here, we report a novel protein, GAP 10, isolated from the gastrolith of the crayfish Cherax quadricarinatus and specifically expressed in its gastrolith disc. The encoding gene was cloned by partial sequencing of the protein extracted from the gastrolith matrix. Based on an assembled microarray cDNA chip, GAP 10 transcripts were found to be highly (12-fold) up-regulated in premolt gastrolith disc and significantly down-regulated in the hypodermis at the same molt stage. The deduced protein sequence of GAP 10 lacks chitin-binding domains and does not show homology to known proteins in the GenBankTM data base. It does, however, have an amino acid composition that has similarity to proteins extracted from invertebrate and ascidian-calcified extracellular matrices. The GAP 10 sequence contains a predicted signal peptide and predicted phosphorylation sites. In addition, the protein is phosphorylated and exhibits calcium-binding ability. Repeated daily injections of GAP 10 double strand RNA to premolt C. quadricarinatus resulted in a prolonged premolt stage and in the development of gastroliths with irregularly rough surfaces. These findings suggest that GAP 10 may be involved in the assembly of the gastrolith chitin-protein-mineral complex, particularly in the deposition of amorphous calcium carbonate. PMID:20150428

  13. A protein involved in the assembly of an extracellular calcium storage matrix.

    PubMed

    Glazer, Lilah; Shechter, Assaf; Tom, Moshe; Yudkovski, Yana; Weil, Simy; Aflalo, Eliahu David; Pamuru, Ramachandra Reddy; Khalaila, Isam; Bentov, Shmuel; Berman, Amir; Sagi, Amir

    2010-04-23

    Gastroliths, the calcium storage organs of crustaceans, consist of chitin-protein-mineral complexes in which the mineral component is stabilized amorphous calcium carbonate. To date, only three proteins, GAP 65, gastrolith matrix protein (GAMP), and orchestin, have been identified in gastroliths. Here, we report a novel protein, GAP 10, isolated from the gastrolith of the crayfish Cherax quadricarinatus and specifically expressed in its gastrolith disc. The encoding gene was cloned by partial sequencing of the protein extracted from the gastrolith matrix. Based on an assembled microarray cDNA chip, GAP 10 transcripts were found to be highly (12-fold) up-regulated in premolt gastrolith disc and significantly down-regulated in the hypodermis at the same molt stage. The deduced protein sequence of GAP 10 lacks chitin-binding domains and does not show homology to known proteins in the GenBank data base. It does, however, have an amino acid composition that has similarity to proteins extracted from invertebrate and ascidian-calcified extracellular matrices. The GAP 10 sequence contains a predicted signal peptide and predicted phosphorylation sites. In addition, the protein is phosphorylated and exhibits calcium-binding ability. Repeated daily injections of GAP 10 double strand RNA to premolt C. quadricarinatus resulted in a prolonged premolt stage and in the development of gastroliths with irregularly rough surfaces. These findings suggest that GAP 10 may be involved in the assembly of the gastrolith chitin-protein-mineral complex, particularly in the deposition of amorphous calcium carbonate. PMID:20150428

  14. Spherulization as a process for the exudation of chemical cues by the encrusting sponge C. crambe.

    PubMed

    Ternon, Eva; Zarate, Lina; Chenesseau, Sandrine; Croué, Julie; Dumollard, Rémi; Suzuki, Marcelino T; Thomas, Olivier P

    2016-01-01

    Ecological interactions in the marine environment are now recognized to be partly held by chemical cues produced by marine organisms. In particular, sponges are sessile animals thought to rely on the bioactive substances they synthesize to ensure their development and defense. However, the mechanisms leading the sponges to use their specialized metabolites as chemical cues remain unknown. Here we report the constant release of bioactive polycyclic guanidinic alkaloids by the Mediterranean sponge Crambe crambe into the dissolved and the particulate phases using a targeted metabolomics study. These compounds were proven to be stored into already described specialized (spherulous) sponge cells and dispersed into the water column after release through the sponge exhaling channels (oscula), leading to a chemical shield surrounding the sponge. Low concentrations of these compounds were demonstrated to have teratogenic effects on embryos of a common sea squirt (ascidian). This mechanism of action called spherulization may therefore contribute to the ecological success of encrusting sponges that need to extend their substrate cover to expand. PMID:27381941

  15. First record of massive blooming of benthic diatoms and their association with megabenthic filter feeders on the shallow seafloor of an Antarctic Fjord: Does glacier melting fuel the bloom?

    NASA Astrophysics Data System (ADS)

    Ahn, In-Young; Moon, Hye-Won; Jeon, Misa; Kang, Sung-Ho

    2016-03-01

    We report a conspicuous benthic diatom bloom on an Antarctic fjord shallow seafloor, which has not been reported elsewhere in Antarctica. A thick and massive growth of benthic diatoms was covering or being entangled with a variety of common benthic megafauna such as stalked ascidians, sponges, tubedwelling polychaetes, gastropods, bryozoans, and others. This finding is an outcome of recent investigations on benthic communities in Marian Cove, King George Island, where glacier retreat has been proceeding quickly for the past several decades. Dominance of benthic diatoms during the austral summer has been frequently reported in shallow Antarctic nearshore waters, which in turn indicates their potential as a primary food item for secondary producers living in this harsh environment. However, previous blooming records of the benthic diatoms were primarily based on data from water column samples. We are the first to report observational evidence of shallow seafloor substrates, including the massive blooming of benthic diatoms and their associations with common benthic megafauna in an Antarctic fjord.

  16. Ecological effects of ocean acidification and habitat complexity on reef-associated macroinvertebrate communities.

    PubMed

    Fabricius, K E; De'ath, G; Noonan, S; Uthicke, S

    2014-01-22

    The ecological effects of ocean acidification (OA) from rising atmospheric carbon dioxide (CO2) on benthic marine communities are largely unknown. We investigated in situ the consequences of long-term exposure to high CO2 on coral-reef-associated macroinvertebrate communities around three shallow volcanic CO2 seeps in Papua New Guinea. The densities of many groups and the number of taxa (classes and phyla) of macroinvertebrates were significantly reduced at elevated CO2 (425-1100 µatm) compared with control sites. However, sensitivities of some groups, including decapod crustaceans, ascidians and several echinoderms, contrasted with predictions of their physiological CO2 tolerances derived from laboratory experiments. High CO2 reduced the availability of structurally complex corals that are essential refugia for many reef-associated macroinvertebrates. This loss of habitat complexity was also associated with losses in many macroinvertebrate groups, especially predation-prone mobile taxa, including crustaceans and crinoids. The transition from living to dead coral as substratum and habitat further altered macroinvertebrate communities, with far more taxa losing than gaining in numbers. Our study shows that indirect ecological effects of OA (reduced habitat complexity) will complement its direct physiological effects and together with the loss of coral cover through climate change will severely affect macroinvertebrate communities in coral reefs. PMID:24307670

  17. Unique features of trabectedin mechanism of action.

    PubMed

    Larsen, Annette K; Galmarini, Carlos M; D'Incalci, Maurizio

    2016-04-01

    Trabectedin (Yondelis(®), ET-743) is a marine-derived natural product that was initially isolated from the marine ascidian Ecteinascidia turbinata and is currently prepared synthetically. Trabectedin is used as a single agent for the treatment of patients with soft tissue sarcoma after failure of doxorubicin or ifosfamide or who are unsuited to receive these agents, and in patients with relapsed, platinum-sensitive ovarian cancer in combination with pegylated liposomal doxorubicin. Trabectedin presents a complex mechanism of action affecting key cell biology processes in tumor cells as well as in the tumor microenvironment. The inhibition of trans-activated transcription and the interaction with DNA repair proteins appear as a hallmark of the antiproliferative activity of trabectedin. Inhibition of active transcription is achieved by an initial direct mechanism that involves interaction with RNA polymerase II, thereby inducing its ubiquitination and degradation by the proteasome. This subsequently modulates the production of cytokines and chemokines by tumor and tumor-associated macrophages. Another interesting effect on activated transcription is mediated by the displacement of oncogenic transcription factors from their target promoters, thereby affecting oncogenic signaling addiction. In addition, it is well established that DNA repair systems including transcription-coupled nucleotide excision repair and homologous recombination play a role in the antitumor activity of trabectedin. Ongoing studies are currently addressing how to exploit these unique mechanistic features of trabectedin to combine this agent either with immunological or microenvironmental modulators or with classical chemotherapeutic agents in a more rational manner. PMID:26666647

  18. Experimental Removal and Recovery of Subtidal Grazers Highlights the Importance of Functional Redundancy and Temporal Context

    PubMed Central

    Elahi, Robin; Sebens, Kenneth P.

    2013-01-01

    The extent to which different grazers are functionally redundant has strong implications for the maintenance of community structure and function. Grazing by red urchins (Strongylocentrotus franciscanus) on temperate rocky reefs can initiate a switch from invertebrate or macroalgal dominance to an algal crust state, but can also cause increases in the density of molluscan mesograzers. In this study, we tested the hypothesis that red urchins and lined chitons (Tonicella spp.) are redundant in the maintenance of available space, defined as encrusting algae and bare rock. In a factorial field experiment replicated at three sites, we reduced the densities of urchins and chitons on subtidal rock walls for nine months. The effects of grazers were interpreted in the context of natural temporal variation by monitoring the benthic community one year before, during, and after grazer removal. The removal of each grazer in isolation had no effect on the epilithic community, but the removal of both grazers caused an increase in sessile invertebrates. The increase was due primarily to clonal ascidians, which displayed a large (∼75%) relative increase in response to the removal of both grazers. However, the observed non-additive responses to grazer removal were temporary and smaller than seasonal fluctuations. Our data demonstrate that urchins and chitons can be redundant in the maintenance of available space, and highlight the value of drawing conclusions from experimental manipulations within an extended temporal context. PMID:24250819

  19. Structure, biosynthesis and possible function of tunichromes and related compounds.

    PubMed

    Sugumaran, Manickam; Robinson, William E

    2012-09-01

    Several species of ascidians (phylum Chordata, subphylum Urochordata) contain a group of oligopeptides called "tunichromes" in their blood cells. These peptides have been implicated in (a) metal chelation and accumulation/sequestration of vanadium or iron; (b) crosslinking of structural fibers in tunic formation, (c) wound healing and (d) defense reactions. However, their biosynthesis, metabolism, and biological function remain largely un-elucidated due to their extreme instability and high reactivity. Tunichromes and related compounds uniquely possess dehydrodopamine moieties, all originating from post-translational modification of peptidyl tyrosine. It is conceivable that the presence of such novel post-translationally modified groups provide attributes that are crucial for their biological roles. Therefore, we examined the chemistry and reactivity of tunichromes in light of the available knowledge of the biochemistry of simple monomeric dehydro-N-acyldopamine units. Based on the reactivity of such simple compounds, the potential biological activities of tunichromes are predicted. Their possible biosynthetic route from peptidyl tyrosine is critically evaluated to provide a better basis for unraveling their biological functions. Prevalence of dehydro-N-acyldopamine units in different tunichromes, some marine antibiotic compounds, insect cuticular sclerotizing precursors and some bioadhesive marine proteins may aid in the de novo design of unique biomaterials with potential antibiotic/adhesive properties. PMID:22580032

  20. Two sexes, one body: intra- and intersex covariation of gamete phenotypes in simultaneous hermaphrodites.

    PubMed

    Monro, Keyne; Marshall, Dustin J

    2014-04-01

    By harboring male and female functions in the same genome and expressing them in every individual, simultaneous hermaphrodites may incur sexual conflict unless both sex functions can evolve phenotypic optima independently of each other. The first step toward understanding their capacity to do so lies in understanding whether sex functions are phenotypically correlated within individuals, but remarkably few data address this issue. We tested the potential for intra- and intersex covariation of gamete phenotypes to mediate sexual conflict in broadcast-spawning hermaphrodites (the ascidians Ciona intestinalis and Pyura praeputialis), for which sex-specific selection acts predominantly on sperm-egg interactions in the water column. In both species, gamete phenotypes covaried within and across sex functions, implying that selection may be unable to target them independently because its direct effects on male gametes translate into correlated effects on female gametes and vice versa. This alone does not preclude the evolution of a different phenotypic optimum for each sex function, but imposes the more restrictive requirement that selection - which ultimately sorts among whole individuals, not sex functions - aligns with the direction in which gamete phenotypes covary at this level. PMID:24834330

  1. Ecological effects of ocean acidification and habitat complexity on reef-associated macroinvertebrate communities

    PubMed Central

    Fabricius, K. E.; De'ath, G.; Noonan, S.; Uthicke, S.

    2014-01-01

    The ecological effects of ocean acidification (OA) from rising atmospheric carbon dioxide (CO2) on benthic marine communities are largely unknown. We investigated in situ the consequences of long-term exposure to high CO2 on coral-reef-associated macroinvertebrate communities around three shallow volcanic CO2 seeps in Papua New Guinea. The densities of many groups and the number of taxa (classes and phyla) of macroinvertebrates were significantly reduced at elevated CO2 (425–1100 µatm) compared with control sites. However, sensitivities of some groups, including decapod crustaceans, ascidians and several echinoderms, contrasted with predictions of their physiological CO2 tolerances derived from laboratory experiments. High CO2 reduced the availability of structurally complex corals that are essential refugia for many reef-associated macroinvertebrates. This loss of habitat complexity was also associated with losses in many macroinvertebrate groups, especially predation-prone mobile taxa, including crustaceans and crinoids. The transition from living to dead coral as substratum and habitat further altered macroinvertebrate communities, with far more taxa losing than gaining in numbers. Our study shows that indirect ecological effects of OA (reduced habitat complexity) will complement its direct physiological effects and together with the loss of coral cover through climate change will severely affect macroinvertebrate communities in coral reefs. PMID:24307670

  2. Acquisition of the dorsal structures in chordate amphioxus

    PubMed Central

    Morov, Arseniy R.; Ukizintambara, Tharcisse; Sabirov, Rushan M.

    2016-01-01

    Acquisition of dorsal structures, such as notochord and hollow nerve cord, is likely to have had a profound influence upon vertebrate evolution. Dorsal formation in chordate development thus has been intensively studied in vertebrates and ascidians. However, the present understanding does not explain how chordates acquired dorsal structures. Here we show that amphioxus retains a key clue to answer this question. In amphioxus embryos, maternal nodal mRNA distributes asymmetrically in accordance with the remodelling of the cortical cytoskeleton in the fertilized egg, and subsequently lefty is first expressed in a patch of blastomeres across the equator where wnt8 is expressed circularly and which will become the margin of the blastopore. The lefty domain co-expresses zygotic nodal by the initial gastrula stage on the one side of the blastopore margin and induces the expression of goosecoid, not-like, chordin and brachyury1 genes in this region, as in the oral ectoderm of sea urchin embryos, which provides a basis for the formation of the dorsal structures. The striking similarity in the gene regulations and their respective expression domains when comparing dorsal formation in amphioxus and the determination of the oral ectoderm in sea urchin embryos suggests that chordates derived from an ambulacrarian-type blastula with dorsoventral inversion. PMID:27307516

  3. The Ciona intestinalis genome: when the constraints are off

    NASA Technical Reports Server (NTRS)

    Holland, Linda Z.; Gibson-Brown, Jeremy J.

    2003-01-01

    The recent genome sequencing of a non-vertebrate deuterostome, the ascidian tunicate Ciona intestinalis, makes a substantial contribution to the fields of evolutionary and developmental biology.1 Tunicates have some of the smallest bilaterian genomes, embryos with relatively few cells, fixed lineages and early determination of cell fates. Initial analyses of the C. intestinalis genome indicate that it has been evolving rapidly. Comparisons with other bilaterians show that C. intestinalis has lost a number of genes, and that many genes linked together in most other bilaterians have become uncoupled. In addition, a number of independent, lineage-specific gene duplications have been detected. These new results, although interesting in themselves, will take on a deeper significance once the genomes of additional invertebrate deuterostomes (e.g. echinoderms, hemichordates and amphioxus) have been sequenced. With such a broadened database, comparative genomics can begin to ask pointed questions about the relationship between the evolution of genomes and the evolution of body plans. Copyright 2003 Wiley Periodicals, Inc.

  4. Genetic Compatibility Underlies Benefits of Mate Choice in an External Fertilizer.

    PubMed

    Aguirre, J David; Blows, Mark W; Marshall, Dustin J

    2016-05-01

    Mate choice is a common feature of sexually reproducing species. In sessile or sedentary external fertilizers, however, direct interactions between reproductive partners are minimal, and instead mate recognition and choice must occur at the level of gametes. It is common for some sperm and egg combinations to have higher fertilization success than others, but it remains unclear whether differences in fertilization reflect gamete-level mate choice (GMC) for paternal quality or parental compatibility. Here, we examine the mechanisms underlying GMC in an externally fertilizing ascidian. A manipulative mate-choice assay confirmed that offspring viability was greater in clutches where we allowed GMC than in clutches where we precluded GMC. A complementary quantitative genetic experiment then revealed that paternal quality effects were generally weaker than parental compatibility effects, particularly for the trait combination underlying the benefits of GMC. Overall, our data suggest that gametes that are more compatible at fertilization produce more viable offspring than gametes that are less compatible at fertilization. Therefore, although the regalia we typically associate with sexual selection are absent in external fertilizers, mechanisms that allow females to bias fertilization in favor of some males over others produce significant fitness benefits in organisms reproducing via the ancestral strategy. PMID:27104996

  5. Tunicates: exploring the sea shores and roaming the open ocean. A tribute to Thomas Huxley.

    PubMed

    Lemaire, Patrick; Piette, Jacques

    2015-06-01

    This review is a tribute to the remarkable contributions of Thomas Huxley to the biology of tunicates, the likely sister group of vertebrates. In 1851, the great biologist and philosopher published two landmark papers on pelagic tunicates in the Philosophical Transactions of the Royal Society. They were dedicated to the description of the adult anatomy and life cycle of thaliaceans and appendicularians, the pelagic relatives of ascidians. In the first part of this review, we discuss the novel anatomical observations and evolutionary hypotheses made by Huxley, which would have a lasting influence on tunicate biology. We also briefly comment on the more philosophical reflections of Huxley on individuality. In the second part, we stress the originality and relevance of past and future studies of tunicates in the resolution of major biological issues. In particular, we focus on the complex relationship between genotype and phenotype and the phenomenon of developmental system drift. We propose that more than 150 years after Huxley's papers, tunicate embryos are still worth studying in their own right, independently of their evolutionary proximity to vertebrates, as they provide original and crucial insights into the process of animal evolution. Tunicates are still at the forefront of biological research. PMID:26085517

  6. Structural shifts of aldehyde dehydrogenase enzymes were instrumental for the early evolution of retinoid-dependent axial patterning in metazoans.

    PubMed

    Sobreira, Tiago J P; Marlétaz, Ferdinand; Simões-Costa, Marcos; Schechtman, Deborah; Pereira, Alexandre C; Brunet, Frédéric; Sweeney, Sarah; Pani, Ariel; Aronowicz, Jochanan; Lowe, Christopher J; Davidson, Bradley; Laudet, Vincent; Bronner, Marianne; de Oliveira, Paulo S L; Schubert, Michael; Xavier-Neto, José

    2011-01-01

    Aldehyde dehydrogenases (ALDHs) catabolize toxic aldehydes and process the vitamin A-derived retinaldehyde into retinoic acid (RA), a small diffusible molecule and a pivotal chordate morphogen. In this study, we combine phylogenetic, structural, genomic, and developmental gene expression analyses to examine the evolutionary origins of ALDH substrate preference. Structural modeling reveals that processing of small aldehydes, such as acetaldehyde, by ALDH2, versus large aldehydes, including retinaldehyde, by ALDH1A is associated with small versus large substrate entry channels (SECs), respectively. Moreover, we show that metazoan ALDH1s and ALDH2s are members of a single ALDH1/2 clade and that during evolution, eukaryote ALDH1/2s often switched between large and small SECs after gene duplication, transforming constricted channels into wide opened ones and vice versa. Ancestral sequence reconstructions suggest that during the evolutionary emergence of RA signaling, the ancestral, narrow-channeled metazoan ALDH1/2 gave rise to large ALDH1 channels capable of accommodating bulky aldehydes, such as retinaldehyde, supporting the view that retinoid-dependent signaling arose from ancestral cellular detoxification mechanisms. Our analyses also indicate that, on a more restricted evolutionary scale, ALDH1 duplicates from invertebrate chordates (amphioxus and ascidian tunicates) underwent switches to smaller and narrower SECs. When combined with alterations in gene expression, these switches led to neofunctionalization from ALDH1-like roles in embryonic patterning to systemic, ALDH2-like roles, suggesting functional shifts from signaling to detoxification. PMID:21169504

  7. Structural shifts of aldehyde dehydrogenase enzymes were instrumental for the early evolution of retinoid-dependent axial patterning in metazoans

    PubMed Central

    Sobreira, Tiago J. P.; Marlétaz, Ferdinand; Simões-Costa, Marcos; Schechtman, Deborah; Pereira, Alexandre C.; Brunet, Frédéric; Sweeney, Sarah; Pani, Ariel; Aronowicz, Jochanan; Lowe, Christopher J.; Davidson, Bradley; Laudet, Vincent; Bronner, Marianne; de Oliveira, Paulo S. L.; Schubert, Michael; Xavier-Neto, José

    2011-01-01

    Aldehyde dehydrogenases (ALDHs) catabolize toxic aldehydes and process the vitamin A-derived retinaldehyde into retinoic acid (RA), a small diffusible molecule and a pivotal chordate morphogen. In this study, we combine phylogenetic, structural, genomic, and developmental gene expression analyses to examine the evolutionary origins of ALDH substrate preference. Structural modeling reveals that processing of small aldehydes, such as acetaldehyde, by ALDH2, versus large aldehydes, including retinaldehyde, by ALDH1A is associated with small versus large substrate entry channels (SECs), respectively. Moreover, we show that metazoan ALDH1s and ALDH2s are members of a single ALDH1/2 clade and that during evolution, eukaryote ALDH1/2s often switched between large and small SECs after gene duplication, transforming constricted channels into wide opened ones and vice versa. Ancestral sequence reconstructions suggest that during the evolutionary emergence of RA signaling, the ancestral, narrow-channeled metazoan ALDH1/2 gave rise to large ALDH1 channels capable of accommodating bulky aldehydes, such as retinaldehyde, supporting the view that retinoid-dependent signaling arose from ancestral cellular detoxification mechanisms. Our analyses also indicate that, on a more restricted evolutionary scale, ALDH1 duplicates from invertebrate chordates (amphioxus and ascidian tunicates) underwent switches to smaller and narrower SECs. When combined with alterations in gene expression, these switches led to neofunctionalization from ALDH1-like roles in embryonic patterning to systemic, ALDH2-like roles, suggesting functional shifts from signaling to detoxification. PMID:21169504

  8. Contribution to the knowledge of cotylean flatworms (Turbellaria, Polycladida) from Iranian coasts: Introducing a new species, with remarks on new records.

    PubMed

    Maghsoudlou, Abdolvahab; Rahimian, Hassan

    2014-01-01

    Very little information is available regarding marine free-living flatworms not only from Iran, but throughout the countries surrounding the Persian Gulf and the Gulf of Oman. The present study first introduces a new euryleptid species, and then reports four pseudocerotid polyclads which inhabit Iranian shallow rocky shores of the Persian Gulf and the Gulf of Oman. Maritigrella makranica sp. nov. is characterized dorsally by a medial cream or white reticulated appearance containing pale orange spots in a honeycomb pattern, a distinct orange submarginal band around the entire body margin and between the marginal tentacles, black spots scattered around mid-dorsal surface, becoming more sparse on raised median region and towards body margin, surrounded by a dark-grey halo around the body midline and orange-black halo towards margin. Three of the four pseudocerotids species belonging to the genera Pseudobiceros Faubel, 1984; Pseudoceros Lang, 1884; and Thysanozoon Grube, 1840, are new records for the studied areas, while the other has been reported in the Persian Gulf previously. Comments on Iranian species are provided and associations of flatworms with ascidians and sponges were observed.  PMID:25283210

  9. The distribution of dimethylsulfoniopropionate in tropical Pacific coral reef invertebrates

    NASA Astrophysics Data System (ADS)

    van Alstyne, Kathryn L.; Schupp, Peter; Slattery, Marc

    2006-08-01

    Dimethylsulfoniopropionate (DMSP) is an important component of the global sulfur cycle and may be involved, via its cleavage product dimethylsulfide, in climate regulation. Although it is common in many algae, reports of DMSP in animals, particularly tropical invertebrates, are limited. This study examined the distribution of DMSP in a diverse group of coral reef invertebrates. DMSP was present in all 22 species of cnidarians and ranged from 9 to 723 μmol g-1 of dry mass (DM) with a mean (± 1SD) of 110 ± 180 μmol g-1 DM. It was not detected in a flatworm and an ascidian or in two of five sponges. Concentrations in sponges ranged from undetectable to 16 μmol g-1 DM with a mean of 4 ± 7 μmol g-1 DM. Within the cnidarians, DMSP concentrations did not differ among orders. Among cnidarian species, DMSP concentrations were correlated with symbiotic zooxanthellae densities. Within cnidarian species, DMSP concentrations of individuals were positively correlated with zooxanthellae densities in three of the four species examined. We speculate that DMSP is dietarily derived in sponges and derived from zooxanthellae in the cnidarians. The functions of DMSP in coral reef invertebrates are not known.

  10. Macrofauna associated to Mycale microsigmatosa (Porifera, Demospongiae) in Rio de Janeiro State, SE Brazil

    NASA Astrophysics Data System (ADS)

    Ribeiro, Suzi M.; Omena, Elianne P.; Muricy, Guilherme

    2003-08-01

    The macrofauna (endo- and epi-biotic) associated to the sponge Mycale ( Carmia) microsigmatosa Arndt, 1927 was studied at three sites in Rio de Janeiro State, Brazil (Arraial do Cabo, Niterói, and Rio de Janeiro). A total of 2235 individuals (over 1 mm long) of 75 invertebrate species were found associated to 19 specimens of the sponge. The most abundant and diverse taxa were the crustaceans (83%, 31 spp.), polychetes (10%, 18 spp.), and molluscs (3.7%, 15 spp.). Cnidarians, platyhelminthes, ascidians, echinoderms, pycnogonids, bryozoans, and sponges were also represented. Amphipod crustaceans were the dominant group, comprising 61% of all individuals collected. Species richness and abundance of associated fauna were highly correlated with sponge volume, but diversity and evenness were not. The site of collection influenced the species composition of the fauna associated to M. microsigmatosa but did not change significantly its diversity, abundance, richness, and dominance patterns of higher taxa. Pregnant females and juvenile stages of 29% of the species associated, including crustaceans, molluscs, echinoderms, and pycnogonids were frequently found inside M. microsigmatosa. Although many of these organisms do occur and reproduce in other habitats outside the sponge as well, M. microsigmatosa is also important for their reproduction and survivorship, thus contributing for the maintenance of biodiversity in Southwestern Atlantic sublittoral rocky shores.

  11. Cryptic species and genetic structure in Didemnum granulatum Tokioka, 1954 (Tunicata: Ascidiacea) from the southern Brazilian coast.

    PubMed

    Bouzon, J L; Vargas, S M; Oliveira Neto, J F; Stoco, P H; Brandini, F P

    2014-11-01

    Didemnum granulatum is a colonial fouling ascidian that lives in subtidal substrates, worldwide. It exhibits two morphotypes, orange and beige. In this study, we verified if the color morphotypes and/or the spatial distribution of specimens in different islands might be associated to patterns of genetic structure of a single species, or if they represent distinct cryptic species. Specimens were collected in four islands, along the coast of the Santa Catarina state. A segment of 490 bp from the mitochondrial gene cytochrome c oxidase subunit 1 (COI) was amplified from 45 samples. Twenty-one haplotypes were identified. The total haplotype diversity (0.912) and the total nucleotide diversity (0.044) were high. The global Fst of the populations analyzed was 0.97, with most of the variation occurring between orange and beige groups (82.19%). The variation found between populations within groups was 15.37%, and 2.45% within populations. Haplotype networks and the neighbor-joining tree showed clear genetic divergence between individuals of distinct colors, and between the islands. These evidences strongly support the presence of a complex of two cryptic species for D. granulatum occupying the studied area. Both species were also highly genetically structured between islands, suggesting that the conservation process of these populations is complex. PMID:25627604

  12. Fouling-resistant surfaces of tropical sea stars.

    PubMed

    Guenther, Jana; Walker-Smith, Genefor; Warén, Anders; De Nys, Rocky

    2007-01-01

    Qualitative evidence suggests sea stars are free of fouling organisms; however the presence of fouling-resistant surfaces of sea stars has not previously been documented. Field surveys were conducted in northern Queensland, Australia, during the wet and dry seasons and several tropical sea star species were examined for surface-associated micro- and macro-organisms. Mean bacterial abundances on seven sea star species were approximately 10(4) to 10(5) cells cm(-2) during both seasons. There were no consistent trends in bacterial abundances with season, species and aboral positions on sea star arms. No common generalist fouling organisms, such as algae, barnacles, serpulid polychaetes, bryozoans and ascidians, were found on any specimens of 12 sea star species. However, low numbers of parasitic and commensal macro-organisms were found on six sea star species. The gastropods Parvioris fulvescens, Asterolamia hians, Thyca (Granulithyca) nardoafrianti and Thyca crystallina were found exclusively on the sea stars Archaster typicus, Astropecten indicus, Nardoa pauciforis and Linckia laevigata, respectively. The shrimp Periclimenes soror was only found on Acanthaster planci, and the polychaete Ophiodromus sp. on A. typicus. The copepods Stellicola illgi and Paramolgus sp. were only found on L. laevigata and Echinaster luzonicus, respectively. As no common generalist fouling organisms were discovered, sea stars offer an excellent model to investigate the mechanisms driving fouling-resistant surfaces and the selective settlement of specialist invertebrates. PMID:17882628

  13. Caprellids (Crustacea: Amphipoda) from India

    NASA Astrophysics Data System (ADS)

    Guerra-García, J. M.; Ganesh, T.; Jaikumar, M.; Raman, A. V.

    2010-12-01

    The caprellid fauna of India is investigated. A total of 538 samples (including algae, seagrasses, sponges, hydroids, ascidians, bryozoans, encrusted dead corals, coral rubble, fine and coarse sediments) were collected from 39 stations along the coast of India, covering a wide diversity of habitats from intertidal to 12 m water depth. A new species ( Jigurru longimanus n.sp.) is described, and figures of the 11 valid species reported so far from India are given together with a key for their identification. No caprellids were found in sediments from the northeast (16-20ºN) coast of India while they were abundant in the southeast and west coast. Decreases in salinity due to river discharges associated with lower values of oxygen, higher water temperatures and lower nutrient inputs along the east coast could explain these differences in caprellid composition between the two coastlines. Significantly, lower abundance of caprellids in India, as in other tropical ecosystems, is probably related to the lack of species belonging to the genus Caprella, which reach very high abundances in temperate waters.

  14. Global diversity of Ascidiacea.

    PubMed

    Shenkar, Noa; Swalla, Billie J

    2011-01-01

    The class Ascidiacea presents fundamental opportunities for research in the fields of development, evolution, ecology, natural products and more. This review provides a comprehensive overview of the current knowledge regarding the global biodiversity of the class Ascidiacea, focusing in their taxonomy, main regions of biodiversity, and distribution patterns. Based on analysis of the literature and the species registered in the online World Register of Marine Species, we assembled a list of 2815 described species. The highest number of species and families is found in the order Aplousobranchia. Didemnidae and Styelidae families have the highest number of species with more than 500 within each group. Sixty percent of described species are colonial. Species richness is highest in tropical regions, where colonial species predominate. In higher latitudes solitary species gradually contribute more to the total species richness. We emphasize the strong association between species richness and sampling efforts, and discuss the risks of invasive species. Our inventory is certainly incomplete as the ascidian fauna in many areas around the world is relatively poorly known, and many new species continue to be discovered and described each year. PMID:21701684

  15. Microcyclamide Biosynthesis in Two Strains of Microcystis aeruginosa: from Structure to Genes and Vice Versa▿ †

    PubMed Central

    Ziemert, Nadine; Ishida, Keishi; Quillardet, Philippe; Bouchier, Christiane; Hertweck, Christian; de Marsac, Nicole Tandeau; Dittmann, Elke

    2008-01-01

    Comparative analysis of related biosynthetic gene clusters can provide new insights into the versatility of these pathways and allow the discovery of new natural products. The freshwater cyanobacterium Microcystis aeruginosa NIES298 produces the cytotoxic peptide microcyclamide. Here, we provide evidence that the cyclic hexapeptide is formed by a ribosomal pathway through the activity of a set of processing enzymes closely resembling those recently shown to be involved in patellamide biosynthesis in cyanobacterial symbionts of ascidians. Besides two subtilisin-type proteases and a heterocyclization enzyme, the gene cluster discovered in strain NIES298 encodes six further open reading frames, two of them without similarity to enzymes encoded by the patellamide gene cluster. Analyses of genomic data of a second cyanobacterial strain, M. aeruginosa PCC 7806, guided the discovery and structural elucidation of two novel peptides of the microcyclamide family. The identification of the microcyclamide biosynthetic genes provided an avenue by which to study the regulation of peptide synthesis at the transcriptional level. The precursor genes were strongly and constitutively expressed throughout the growth phase, excluding the autoinduction of these peptides, as has been observed for several peptide pheromone families in bacteria. PMID:18245249

  16. Patellamide A and C biosynthesis by a microcin-like pathway in Prochloron didemni, the cyanobacterial symbiont of Lissoclinum patella

    PubMed Central

    Schmidt, Eric W.; Nelson, James T.; Rasko, David A.; Sudek, Sebastian; Eisen, Jonathan A.; Haygood, Margo G.; Ravel, Jacques

    2005-01-01

    Prochloron spp. are obligate cyanobacterial symbionts of many didemnid family ascidians. It has been proposed that the cyclic peptides of the patellamide class found in didemnid extracts are synthesized by Prochloron spp., but studies in which host and symbiont cells are separated and chemically analyzed to identify the biosynthetic source have yielded inconclusive results. As part of the Prochloron didemni sequencing project, we identified patellamide biosynthetic genes and confirmed their function by heterologous expression of the whole pathway in Escherichia coli. The primary sequence of patellamides A and C is encoded on a single ORF that resembles a precursor peptide. We propose that this prepatellamide is heterocyclized to form thiazole and oxazoline rings, and the peptide is cleaved to yield the two cyclic patellamides, A and C. This work represents the full sequencing and functional expression of a marine natural-product pathway from an obligate symbiont. In addition, a related cluster was identified in Trichodesmium erythraeum IMS101, an important bloom-forming cyanobacterium. PMID:15883371

  17. NMR structural determination of unique invertebrate glycosaminoglycans endowed with medical properties.

    PubMed

    Pomin, Vitor H

    2015-09-01

    Glycosaminoglycans (GAGs) are sulfated polysaccharides of complex structure endowed with numerous biomedical functions. Although ubiquitously distributed in vertebrates, GAGs can also occur in certain terrestrial or marine invertebrates. Solution nuclear magnetic resonance (NMR) spectroscopy has been the analytical technique mostly employed in structural characterization of GAGs from any source. This review aims at illustrating the application of NMR in structural determination of few representative invertebrate GAG examples of unique structures and endowed with therapeutic actions. They are the holothurian fucosylated chondroitin sulfate, the acharan sulfate isolated from the snail Achatina fulica, the dermatan sulfates with distinct sulfation patterns extracted from ascidian species, the sulfated glucuronic acid-containing heparan sulfate isolated from the gastropode Nodipecten nodosum, and the hybrid heparin/heparan sulfate molecule obtained from the shrimp Litopenaeus vannamei. These invertebrate GAGs exhibit distinct structures when compared to those extracted from mammalian GAGs. The distinct structures of the invertebrate GAGs lead also to different mechanisms of actions as compared to the mammalian GAG standards. Invertebrate GAGs comprise promising therapeutic candidates in fights against diseases. Solution NMR has been playing a pivotal role in this carbohydrate-based drug research, discovery and development. PMID:26083200

  18. Bioactive Peptides and Depsipeptides with Anticancer Potential: Sources from Marine Animals

    PubMed Central

    Suarez-Jimenez, Guadalupe-Miroslava; Burgos-Hernandez, Armando; Ezquerra-Brauer, Josafat-Marina

    2012-01-01

    Biologically active compounds with different modes of action, such as, antiproliferative, antioxidant, antimicrotubule, have been isolated from marine sources, specifically algae and cyanobacteria. Recently research has been focused on peptides from marine animal sources, since they have been found as secondary metabolites from sponges, ascidians, tunicates, and mollusks. The structural characteristics of these peptides include various unusual amino acid residues which may be responsible for their bioactivity. Moreover, protein hydrolysates formed by the enzymatic digestion of aquatic and marine by-products are an important source of bioactive peptides. Purified peptides from these sources have been shown to have antioxidant activity and cytotoxic effect on several human cancer cell lines such as HeLa, AGS, and DLD-1. These characteristics imply that the use of peptides from marine sources has potential for the prevention and treatment of cancer, and that they might also be useful as molecular models in anticancer drug research. This review focuses on the latest studies and critical research in this field, and evidences the immense potential of marine animals as bioactive peptide sources. PMID:22822350

  19. Spherulization as a process for the exudation of chemical cues by the encrusting sponge C. crambe

    PubMed Central

    Ternon, Eva; Zarate, Lina; Chenesseau, Sandrine; Croué, Julie; Dumollard, Rémi; Suzuki, Marcelino T.; Thomas, Olivier P.

    2016-01-01

    Ecological interactions in the marine environment are now recognized to be partly held by chemical cues produced by marine organisms. In particular, sponges are sessile animals thought to rely on the bioactive substances they synthesize to ensure their development and defense. However, the mechanisms leading the sponges to use their specialized metabolites as chemical cues remain unknown. Here we report the constant release of bioactive polycyclic guanidinic alkaloids by the Mediterranean sponge Crambe crambe into the dissolved and the particulate phases using a targeted metabolomics study. These compounds were proven to be stored into already described specialized (spherulous) sponge cells and dispersed into the water column after release through the sponge exhaling channels (oscula), leading to a chemical shield surrounding the sponge. Low concentrations of these compounds were demonstrated to have teratogenic effects on embryos of a common sea squirt (ascidian). This mechanism of action called spherulization may therefore contribute to the ecological success of encrusting sponges that need to extend their substrate cover to expand. PMID:27381941

  20. Characteristics of the Mesophotic Megabenthic Assemblages of the Vercelli Seamount (North Tyrrhenian Sea)

    PubMed Central

    Bo, Marzia; Bertolino, Marco; Borghini, Mireno; Castellano, Michela; Covazzi Harriague, Anabella; Di Camillo, Cristina Gioia; Gasparini, GianPietro; Misic, Cristina; Povero, Paolo; Pusceddu, Antonio; Schroeder, Katrin; Bavestrello, Giorgio

    2011-01-01

    The biodiversity of the megabenthic assemblages of the mesophotic zone of a Tyrrhenian seamount (Vercelli Seamount) is described using Remotely Operated Vehicle (ROV) video imaging from 100 m depth to the top of the mount around 61 m depth. This pinnacle hosts a rich coralligenous community characterized by three different assemblages: (i) the top shows a dense covering of the kelp Laminaria rodriguezii; (ii) the southern side biocoenosis is mainly dominated by the octocorals Paramuricea clavata and Eunicella cavolinii; while (iii) the northern side of the seamount assemblage is colonized by active filter-feeding organisms such as sponges (sometimes covering 100% of the surface) with numerous colonies of the ascidian Diazona violacea, and the polychaete Sabella pavonina. This study highlights, also for a Mediterranean seamount, the potential role of an isolated rocky peak penetrating the euphotic zone, to work as an aggregating structure, hosting abundant benthic communities dominated by suspension feeders, whose distribution may vary in accordance to the geomorphology of the area and the different local hydrodynamic conditions. PMID:21304906

  1. Defensive Metabolites from Antarctic Invertebrates: Does Energetic Content Interfere with Feeding Repellence?

    PubMed Central

    Núñez-Pons, Laura; Avila, Conxita

    2014-01-01

    Many bioactive products from benthic invertebrates mediating ecological interactions have proved to reduce predation, but their mechanisms of action, and their molecular identities, are usually unknown. It was suggested, yet scarcely investigated, that nutritional quality interferes with defensive metabolites. This means that antifeedants would be less effective when combined with energetically rich prey, and that higher amounts of defensive compounds would be needed for predator avoidance. We evaluated the effects of five types of repellents obtained from Antarctic invertebrates, in combination with diets of different energetic values. The compounds came from soft corals, ascidians and hexactinellid sponges; they included wax esters, alkaloids, a meroterpenoid, a steroid, and the recently described organic acid, glassponsine. Feeding repellency was tested through preference assays by preparing diets (alginate pearls) combining different energetic content and inorganic material. Experimental diets contained various concentrations of each repellent product, and were offered along with control compound-free pearls, to the Antarctic omnivore amphipod Cheirimedon femoratus. Meridianin alkaloids were the most active repellents, and wax esters were the least active when combined with foods of distinct energetic content. Our data show that levels of repellency vary for each compound, and that they perform differently when mixed with distinct assay foods. The natural products that interacted the most with energetic content were those occurring in nature at higher concentrations. The bioactivity of the remaining metabolites tested was found to depend on a threshold concentration, enough to elicit feeding repellence, independently from nutritional quality. PMID:24962273

  2. Gordonia didemni sp. nov. an actinomycete isolated from the marine ascidium Didemnum sp.

    PubMed

    de Menezes, Cláudia Beatriz Afonso; Afonso, Rafael Sanches; de Souza, Wallace Rafael; Parma, Márcia; de Melo, Itamar Soares; Zucchi, Tiago Domingues; Fantinatti-Garboggini, Fabiana

    2016-02-01

    A novel actinobacterium, designated isolate B204(T), was isolated from a marine ascidian Didemnum sp., collected from São Paulo, Brazil, and its taxonomic position established using data from a polyphasic study. The organism showed a combination of chemotaxonomic and morphological characteristics consistent with its classification in the genus Gordonia and formed a distinct phyletic line in the Gordonia 16S rRNA gene tree. It was closely related to Gordonia terrae DSM 43249(T) (99.9 % 16S rRNA gene sequence similarity) and Gordonia lacunae DSM 45085(T) (99.3 % 16S rRNA gene sequence similarity) but was distinguished from these strains by a moderate level of DNA-DNA relatedness (63.0 and 54.7 %) and discriminatory phenotypic properties. Based on the data obtained, the isolate B204(T) (=CBMAI 1069(T) = DSM 46679(T)) should therefore be classified as the type strain of a novel species of the genus Gordonia, for which the name Gordonia didemni sp. nov. is proposed. PMID:26678782

  3. Evolutionary origins of the vertebrate heart: Specification of the cardiac lineage in Ciona intestinalis

    PubMed Central

    Davidson, Brad; Levine, Michael

    2003-01-01

    Here we exploit the extensive cell lineage information and streamlined genome of the ascidian, Ciona intestinalis, to investigate heart development in a basal chordate. Several cardiac genes were analyzed, including the sole Ciona ortholog of the Drosophila tinman gene, and tissue-specific enhancers were isolated for some of the genes. Conserved sequence motifs within these enhancers facilitated the isolation of a heart enhancer for the Ciona Hand-like gene. Altogether, these studies provide a regulatory framework for the differentiation of the cardiac mesoderm, beginning at the 110-cell stage, and extending through the fusion of cardiac progenitors during tail elongation. The cardiac lineage shares a common origin with the germ line, and zygotic transcription is first detected in the heart progenitors only after its separation from the germ line at the 64-cell stage. We propose that germ-line determinants influence the specification of the cardiac mesoderm, both by inhibiting inductive signals required for the development of noncardiac mesoderm lineages, and by providing a localized source of Wnt-5 and other signals required for heart development. We discuss the possibility that the germ line also influences the specification of the vertebrate heart. PMID:14500781

  4. Toll-Like Receptors of Deuterostome Invertebrates

    PubMed Central

    Satake, Honoo; Sekiguchi, Toshio

    2012-01-01

    Defensive systems against pathogens are responsible not only for survival or lifetime of an individual but also for the evolution of a species. Innate immunity is expected to be more important for invertebrates than mammals, given that adaptive immunity has not been acquired in the former. Toll-like receptors (TLRs) have been shown to play a crucial role in host defense of pathogenic microbes in innate immunity of mammals. Recent genome-wide analyses have suggested that TLR or their related genes are conserved in invertebrates. In particular, numerous TLR-related gene candidates were detected in deuterostome invertebrates, including a sea urchin (222 TLR-related gene candidates) and amphioxus (72 TLR-related gene candidates). Molecular phylogenetic analysis verified that most of sea urchin or amphioxus TLR candidates are paralogous, suggesting that these organisms expanded TLR-related genes in a species-specific manner. In contrast, another deuterostome invertebrate, the ascidian Ciona intestinalis, was found to possess only two TLR genes. Moreover, Ciona TLRs, Ci-TLR1 and Ci-TLR2, were shown to possess “hybrid” functionality of mammalian TLRs. Such functionality of Ci-TLRs could not be predicted by sequence comparison with vertebrate TLRs, indicating confounding evolutionary lineages of deuterostome invertebrate TLRs or their candidates. In this review article, we present recent advances in studies of TLRs or their candidates among deuterostome invertebrates, and provide insight into an evolutionary process of TLRs. PMID:22566918

  5. Forming a tough shell via an intracellular matrix and cellular junctions in the tail epidermis of Oikopleura dioica (Chordata: Tunicata: Appendicularia)

    NASA Astrophysics Data System (ADS)

    Nakashima, Keisuke; Nishino, Atsuo; Hirose, Euichi

    2011-08-01

    A postanal tail is a major synapomorphy of the phylum Chordata, which is composed of three subphyla: Vertebrata, Cephalochordata, and Tunicata (Urochordata). Among tunicates, appendicularians are the only group that retains the tail in the adult, and the adult tail functions in locomotion and feeding in combination with a cellulose-based house structure. Given the phylogenetic position of tunicates, the appendicularian adult tail may possess ancestral features of the chordate tail. We assess the ultrastructural development of the tail epidermis of the appendicularian Oikopleura dioica. The epidermis of the larval tail is enclosed by the larval envelope, which is a thin sheet similar to the outer tunic layer of ascidian larvae. The epidermis of the adult tail seems to bear no tunic-like cellulosic integuments, and the tail fin is a simple folding of the epidermis. Every epidermal cell, except for the triangular cells at the edge of the tail fin, has a conspicuous matrix layer of fibrous content in the apical cytoplasm without enclosing membranes. The epidermis of the larval tail does not have a fibrous matrix layer, suggesting the production of the layer during larval development and metamorphosis. Zonulae adhaerentes firmly bind the epidermal cells of the adult tail to one another, and the dense microfilaments lining the cell borders constitute a mechanical support for the cell membranes. The intracellular matrix, cell junctions, and cytoskeletons probably make the tail epidermis a tough, flexible shell supporting the active beating of the oikopleuran adult tail.

  6. An epizootic of Florida manatees associated with a dinoflagellate bloom

    USGS Publications Warehouse

    O'Shea, T.J.; Rathbun, G.B.; Bonde, R.K.; Buergelt, C.D.; Odell, D.K.

    1991-01-01

    Over a 10-wk period in early 1982, 39 Florida manatees (Trichechus manatus latirostris) were found dead in the lower Caloosahatchee River and nearby waters of southwestern Florida. Two were killed by boats. The remainder showed no evidence of trauma. Lesions indicative of infectious agents were not identified, and bacteriological and contaminant residue findings were unremarkable. Nonspecific lesions of congestion and hemorrhage were identified in brain tissue. Numerous reports were also received of manatee morbidity. Some distressed manatees showed no biochemical lesions in clinical analyses of blood samples and recovered quickly. Timing of manatee illnesses coincided with fish and double-crested cormorant (Phalacrocorax auritus) mortality and morbidity. A widespread bloom of the dinoflagellate red tide organism (Gymnodinium breve) also coincided with these incidents. G. breve produces potent neurotoxins (brevetoxins). Circumstantial evidence links these events, and possible routes of exposure may include ingestion of filter-feeding ascidians. Ecological conditions that magnified the extent of the epizootic included an early dispersal of manatees into the area from a nearby winter aggregation site and unusually high salinities that facilitated the inshore spread of the red tide bloom. Management responses to future episodes of red tide in manatee areas are suggested.

  7. Climate change and glacier retreat drive shifts in an Antarctic benthic ecosystem

    PubMed Central

    Sahade, Ricardo; Lagger, Cristian; Torre, Luciana; Momo, Fernando; Monien, Patrick; Schloss, Irene; Barnes, David K. A.; Servetto, Natalia; Tarantelli, Soledad; Tatián, Marcos; Zamboni, Nadia; Abele, Doris

    2015-01-01

    The Antarctic Peninsula (AP) is one of the three places on Earth that registered the most intense warming in the last 50 years, almost five times the global mean. This warming has strongly affected the cryosphere, causing the largest ice-shelf collapses ever observed and the retreat of 87% of glaciers. Ecosystem responses, although increasingly predicted, have been mainly reported for pelagic systems. However, and despite most Antarctic species being benthic, responses in the Antarctic benthos have been detected in only a few species, and major effects at assemblage level are unknown. This is probably due to the scarcity of baselines against which to assess change. We performed repeat surveys of coastal benthos in 1994, 1998, and 2010, analyzing community structure and environmental variables at King George Island, Antarctica. We report a marked shift in an Antarctic benthic community that can be linked to ongoing climate change. However, rather than temperature as the primary factor, we highlight the resulting increased sediment runoff, triggered by glacier retreat, as the potential causal factor. The sudden shift from a “filter feeders–ascidian domination” to a “mixed assemblage” suggests that thresholds (for example, of tolerable sedimentation) and alternative equilibrium states, depending on the reversibility of the changes, could be possible traits of this ecosystem. Sedimentation processes will be increasing under the current scenario of glacier retreat, and attention needs to be paid to its effects along the AP. PMID:26702429

  8. Recent sediment remolding on a deep shelf, Ross Sea: implications for radiocarbon dating of Antarctic marine sediments

    NASA Astrophysics Data System (ADS)

    Domack, Eugene W.; Taviani, Marco; Rodriguez, Anthonio

    1999-11-01

    Coarse, bioclastic rich sands have been widely reported from the banks of the Antarctic continental shelf but their origin is still poorly known. We report on a suite of coarse sediments recovered from the top of the Mawson Bank in the northwestern Ross Sea. Radiocarbon ages of biogenic calcite, for modern and apparently late Pleistocene deposits, range from 1085±45 to 20,895±250 yr B.P.. Discovery of soft tissue (Ascidian) preserved as an incrustation on a pebble at 2 m depth indicates aggregation of the sediment within several months or a year of core recovery. Radiocarbon ages of acid insoluble organic matter (aiom) are less than those of the foraminifera calcite. The aiom ages are also reversed in sequence, indicating reworking of the sediment during deposition. These observations and a review of recently published literature suggest that much of the bank top sediment in Antarctica is presently undergoing remobilization, under the influence of strong currents and/or icebergs even under interglacical (high-stand) sea levels. These observations point out the need for careful, integrated studies on high latitude marine sediment cores before resultant "ages" alone are used as the foundation for paleoglacial reconstructions.

  9. Bioaccumulation of Vanadium by Vanadium-Resistant Bacteria Isolated from the Intestine of Ascidia sydneiensis samea.

    PubMed

    Romaidi; Ueki, Tatsuya

    2016-06-01

    Isolation of naturally occurring bacterial strains from metal-rich environments has gained popularity due to the growing need for bioremediation technologies. In this study, we found that the vanadium concentration in the intestine of the vanadium-rich ascidian Ascidia sydneiensis samea could reach 0.67 mM, and thus, we isolated vanadium-resistant bacteria from the intestinal contents and determined the ability of each bacterial strain to accumulate vanadium and other heavy metals. Nine strains of vanadium-resistant bacteria were successfully isolated, of which two strains, V-RA-4 and S-RA-6, accumulated vanadium at a higher rate than did the other strains. The maximum vanadium absorption by these bacteria was achieved at pH 3, and intracellular accumulation was the predominant mechanism. Each strain strongly accumulated copper and cobalt ions, but accumulation of nickel and molybdate ions was relatively low. These bacterial strains can be applied to protocols for bioremediation of vanadium and heavy metal toxicity. PMID:27177911

  10. Modelling distribution of marine benthos from hydroacoustics and underwater video

    NASA Astrophysics Data System (ADS)

    Holmes, K. W.; Van Niel, K. P.; Radford, B.; Kendrick, G. A.; Grove, S. L.

    2008-08-01

    Broad-scale mapping of marine benthos is required for marine resource management and conservation. This study combines textural derivatives based on bathymetry from multibeam hydroacoustics with underwater video observations to model and map sessile biota between 10- and 60-m water depth over 35 km 2 in Point Addis Marine National Park (MNP), Vic., Australia. Classification tree models and maps were developed for macroalgae (all types, mixed red algae, Ecklonia, and rhodoliths) and sessile invertebrates (all types, sponges, and ascidians). Model accuracy was tested on 25% of the video observation dataset reserved from modelling. Models fit well for most macroalgae categories (correct classification rates of 67-84%), but are not as good for sessile invertebrate classes (correct classification rates of 57-62%). The poor fit of the sessile invertebrate models may be the combined result of grouping organisms with different environmental requirements and the effect of false absences recorded during video interpretation due to poor image quality. Probability maps, binary single-class maps, and multi-class maps supply spatially explicit, detailed information on the distribution of sessile benthic biota within the MNP and provide information at a landscape-scale for ecological investigations and marine management.

  11. Functional Brachyury Binding Sites Establish a Temporal Read-out of Gene Expression in the Ciona Notochord

    PubMed Central

    Passamaneck, Yale J.; Gazdoiu, Stefan; José-Edwards, Diana S.; Kugler, Jamie E.; Oda-Ishii, Izumi; Imai, Janice H.; Nibu, Yutaka; Di Gregorio, Anna

    2013-01-01

    The appearance of the notochord represented a milestone in Deuterostome evolution. The notochord is necessary for the development of the chordate body plan and for the formation of the vertebral column and numerous organs. It is known that the transcription factor Brachyury is required for notochord formation in all chordates, and that it controls transcription of a large number of target genes. However, studies of the structure of the cis-regulatory modules (CRMs) through which this control is exerted are complicated in vertebrates by the genomic complexity and the pan-mesodermal expression territory of Brachyury. We used the ascidian Ciona, in which the single-copy Brachyury is notochord-specific and CRMs are easily identifiable, to carry out a systematic characterization of Brachyury-downstream notochord CRMs. We found that Ciona Brachyury (Ci-Bra) controls most of its targets directly, through non-palindromic binding sites that function either synergistically or individually to activate early- and middle-onset genes, respectively, while late-onset target CRMs are controlled indirectly, via transcriptional intermediaries. These results illustrate how a transcriptional regulator can efficiently shape a shallow gene regulatory network into a multi-tiered transcriptional output, and provide insights into the mechanisms that establish temporal read-outs of gene expression in a fast-developing chordate embryo. PMID:24204212

  12. 3D-Printed Microwell Arrays for Ciona Microinjection and Timelapse Imaging

    PubMed Central

    Gregory, Clint; Veeman, Michael

    2013-01-01

    Ascidians such as Ciona are close chordate relatives of the vertebrates with small, simple embryonic body plans and small, simple genomes. The tractable size of the embryo offers considerable advantages for in toto imaging and quantitative analysis of morphogenesis. For functional studies, Ciona eggs are considerably more challenging to microinject than the much larger eggs of other model organisms such as zebrafish and Xenopus. One of the key difficulties is in restraining the eggs so that the microinjection needle can be easily introduced and withdrawn. Here we develop and test a device to cast wells in agarose that are each sized to hold a single egg. This injection mold is fabricated by micro-resolution stereolithography with a grid of egg-sized posts that cast corresponding wells in agarose. This 3D printing technology allows the rapid and inexpensive testing of iteratively refined prototypes. In addition to their utility in microinjection, these grids of embryo-sized wells are also valuable for timelapse imaging of multiple embryos. PMID:24324769

  13. Acquisition of the dorsal structures in chordate amphioxus.

    PubMed

    Morov, Arseniy R; Ukizintambara, Tharcisse; Sabirov, Rushan M; Yasui, Kinya

    2016-06-01

    Acquisition of dorsal structures, such as notochord and hollow nerve cord, is likely to have had a profound influence upon vertebrate evolution. Dorsal formation in chordate development thus has been intensively studied in vertebrates and ascidians. However, the present understanding does not explain how chordates acquired dorsal structures. Here we show that amphioxus retains a key clue to answer this question. In amphioxus embryos, maternal nodal mRNA distributes asymmetrically in accordance with the remodelling of the cortical cytoskeleton in the fertilized egg, and subsequently lefty is first expressed in a patch of blastomeres across the equator where wnt8 is expressed circularly and which will become the margin of the blastopore. The lefty domain co-expresses zygotic nodal by the initial gastrula stage on the one side of the blastopore margin and induces the expression of goosecoid, not-like, chordin and brachyury1 genes in this region, as in the oral ectoderm of sea urchin embryos, which provides a basis for the formation of the dorsal structures. The striking similarity in the gene regulations and their respective expression domains when comparing dorsal formation in amphioxus and the determination of the oral ectoderm in sea urchin embryos suggests that chordates derived from an ambulacrarian-type blastula with dorsoventral inversion. PMID:27307516

  14. A thermodynamic study of sperm-egg interaction.

    PubMed Central

    Elia, V; Rosati, F; Barone, G; Monroy, A; Liquori, A M

    1983-01-01

    We have studied the binding of spermatozoa to the receptor sites on the vitelline coat (VC) of glycerol-treated eggs (ghost eggs) of the Ascidian, Ciona intestinalis (Protochordate). Glycerol treatment cytolyses the egg without affecting the ability of the VC to bind spermatozoa in a species-specific manner; however, in this system binding is not followed by the acrosome reaction. The ghost eggs are metabolically inert. As a base line for our analysis, we have studied the concentration-dependent heat evolved and oxygen consumption of spermatozoa when diluted in sea water. The process has been analyzed on the basis of equations derived by Liquori and Tripiciano to describe cell growth. Upon binding to the ghost eggs, the spermatozoa produce an explosive heat evolution (excess heat) which is not accompanied by oxygen consumption. The excess heat produced plotted against sperm concentration (at constant egg concentrations) gives an asymmetric bell-shaped curve. This is interpreted as being due to the competitive effect of sperm agglutination at a high sperm concentration. It is concluded that only spermatozoa that attach singly (monomeric spermatozoa) to the egg undergo metabolic activation. Images Fig. 1. Fig. 6. PMID:6641711

  15. Succession in subtidal macrofouling assemblages of a Patagonian harbour (Argentina, SW Atlantic)

    NASA Astrophysics Data System (ADS)

    Rico, Alicia; Peralta, Roxana; López Gappa, Juan

    2012-12-01

    Subtidal fouling assemblages usually consist of short-lived organisms. Colonisation sequences on man-made structures may thus be greatly affected by the temporal and spatial variability of propagule supply. This study explores the influence of seasonality on succession in the macrofouling assemblage of a Patagonian harbour (Argentina, Southwest Atlantic). Replicated artificial substrata were suspended horizontally and sampled at quarterly intervals during 1 year. The influence of seasonality on 1-year-old assemblages was further analysed using additional sets of replicated panels submersed at different seasons and collected 1 year later. Upper surfaces were always dominated by ephemeral algae, while lower surfaces exhibited high coverage of filter-feeding invertebrates. Regardless of submersion length, species richness was significantly higher on lower than on upper surfaces. A significant interaction between orientation and submersion length was found for the Shannon diversity index, meaning that temporal changes in diversity depended on substratum orientation. On the lower surfaces, diversity reached a maximum after 9 months and then declined, mainly due to extensive dislodgment of two species of ascidians. On algal-dominated upper surfaces, differences in structure of annual assemblages were due to seasonal changes in the abundance of ephemeral algae. This study shows that constancy or variability of 1-year-old assemblages whose development began at different seasons depended greatly on the life history of the organisms that settled and managed to persist on both surfaces, which in turn depended on substratum orientation.

  16. Investigating the widespread introduction of a tropical marine fouling species.

    PubMed

    Sheets, Elizabeth A; Cohen, C Sarah; Ruiz, Gregory M; da Rocha, Rosana M

    2016-04-01

    Little is known about the number and rate of introductions into terrestrial and marine tropical regions, and if introduction patterns and processes differ from temperate latitudes. Botryllid ascidians (marine invertebrate chordates) are an interesting group to study such introduction differences because several congeners have established populations across latitudes. While temperate botryllid invasions have been repeatedly highlighted, the global spread of tropical Botrylloides nigrum (Herdman, 1886) has been largely ignored. We sampled B. nigrum from 16 worldwide warm water locations, including around the Panama Canal, one of the largest shipping hubs in the world and a possible introduction corridor. Using mitochondrial (COI) and nuclear (ANT) markers, we discovered a single species with low genetic divergence and diversity that has established in the Atlantic, Pacific, Indo-Pacific, and Mediterranean Oceans. The Atlantic Ocean contained the highest diversity and multilocus theta estimates and may be a source for introductions to other regions. A high frequency of one mitochondrial haplotype was detected in Pacific populations that may represent a recent introduction in this region. In comparison to temperate relatives, B. nigrum displayed lower (but similar to temperate Botrylloides violaceus) genetic divergence and diversity at both loci that may represent a more recent global spread or differences in introduction pressures in tropical regions. Additionally, chimeras (genetically distinct individuals sharing a single body) were detected in three populations by the mitochondrial locus and validated using cloning, and these individuals contained new haplotype diversity not detected in any other colonies. PMID:27066231

  17. A non-oxo methanolate-bridged divanadium(IV) complex with tris(2-sulfanidylphenyl)phosphane ligands: synthesis, structural characterization and magnetic investigation.

    PubMed

    Wu, Hong Ming; Chang, Ya Ho; Su, Chia Lin; Lee, Gene Hsiang; Hsu, Hua Fen

    2016-05-01

    Vanadium chemistry is of interest due its biological relevance and medical applications. In particular, the interactions of high-valent vanadium ions with sulfur-containing biologically important molecules, such as cysteine and glutathione, might be related to the redox conversion of vanadium in ascidians, the function of amavadin (a vanadium-containing anion) and the antidiabetic behaviour of vanadium compounds. A mechanistic understanding of these aspects is important. In an effort to investigate high-valent vanadium-sulfur chemistry, we have synthesized and characterized the non-oxo divanadium(IV) complex salt tetraphenylphosphonium tri-μ-methanolato-κ(6)O:O-bis({tris[2-sulfanidyl-3-(trimethylsilyl)phenyl]phosphane-κ(4)P,S,S',S''}vanadium(IV)) methanol disolvate, (C24H20P)[V(IV)2(μ-OCH3)3(C27H36PS3)2]·2CH3OH. Two V(IV) metal centres are bridged by three methanolate ligands, giving a C2-symmetric V2(μ-OMe)3 core structure. Each V(IV) centre adopts a monocapped trigonal antiprismatic geometry, with the P atom situated in the capping position and the three S atoms and three O atoms forming two triangular faces of the trigonal antiprism. The magnetic data indicate a paramagnetic nature of the salt, with an S = 1 spin state. PMID:27146571

  18. Characteristics of the mesophotic megabenthic assemblages of the vercelli seamount (north tyrrhenian sea).

    PubMed

    Bo, Marzia; Bertolino, Marco; Borghini, Mireno; Castellano, Michela; Covazzi Harriague, Anabella; Di Camillo, Cristina Gioia; Gasparini, Gianpietro; Misic, Cristina; Povero, Paolo; Pusceddu, Antonio; Schroeder, Katrin; Bavestrello, Giorgio

    2011-01-01

    The biodiversity of the megabenthic assemblages of the mesophotic zone of a Tyrrhenian seamount (Vercelli Seamount) is described using Remotely Operated Vehicle (ROV) video imaging from 100 m depth to the top of the mount around 61 m depth. This pinnacle hosts a rich coralligenous community characterized by three different assemblages: (i) the top shows a dense covering of the kelp Laminaria rodriguezii; (ii) the southern side biocoenosis is mainly dominated by the octocorals Paramuricea clavata and Eunicella cavolinii; while (iii) the northern side of the seamount assemblage is colonized by active filter-feeding organisms such as sponges (sometimes covering 100% of the surface) with numerous colonies of the ascidian Diazona violacea, and the polychaete Sabella pavonina. This study highlights, also for a Mediterranean seamount, the potential role of an isolated rocky peak penetrating the euphotic zone, to work as an aggregating structure, hosting abundant benthic communities dominated by suspension feeders, whose distribution may vary in accordance to the geomorphology of the area and the different local hydrodynamic conditions. PMID:21304906

  19. Physical association between a novel plasma-membrane structure and centrosome orients cell division

    PubMed Central

    Negishi, Takefumi; Miyazaki, Naoyuki; Murata, Kazuyoshi; Yasuo, Hitoyoshi; Ueno, Naoto

    2016-01-01

    In the last mitotic division of the epidermal lineage in the ascidian embryo, the cells divide stereotypically along the anterior-posterior axis. During interphase, we found that a unique membrane structure invaginates from the posterior to the centre of the cell, in a microtubule-dependent manner. The invagination projects toward centrioles on the apical side of the nucleus and associates with one of them. Further, a cilium forms on the posterior side of the cell and its basal body remains associated with the invagination. A laser ablation experiment suggests that the invagination is under tensile force and promotes the posterior positioning of the centrosome. Finally, we showed that the orientation of the invaginations is coupled with the polarized dynamics of centrosome movements and the orientation of cell division. Based on these findings, we propose a model whereby this novel membrane structure orchestrates centrosome positioning and thus the orientation of cell division axis. DOI: http://dx.doi.org/10.7554/eLife.16550.001 PMID:27502556

  20. Tunicates: exploring the sea shores and roaming the open ocean. A tribute to Thomas Huxley

    PubMed Central

    Lemaire, Patrick; Piette, Jacques

    2015-01-01

    This review is a tribute to the remarkable contributions of Thomas Huxley to the biology of tunicates, the likely sister group of vertebrates. In 1851, the great biologist and philosopher published two landmark papers on pelagic tunicates in the Philosophical Transactions of the Royal Society. They were dedicated to the description of the adult anatomy and life cycle of thaliaceans and appendicularians, the pelagic relatives of ascidians. In the first part of this review, we discuss the novel anatomical observations and evolutionary hypotheses made by Huxley, which would have a lasting influence on tunicate biology. We also briefly comment on the more philosophical reflections of Huxley on individuality. In the second part, we stress the originality and relevance of past and future studies of tunicates in the resolution of major biological issues. In particular, we focus on the complex relationship between genotype and phenotype and the phenomenon of developmental system drift. We propose that more than 150 years after Huxley's papers, tunicate embryos are still worth studying in their own right, independently of their evolutionary proximity to vertebrates, as they provide original and crucial insights into the process of animal evolution. Tunicates are still at the forefront of biological research. PMID:26085517

  1. Transcription factors ETS2 and MESP1 transdifferentiate human dermal fibroblasts into cardiac progenitors.

    PubMed

    Islas, Jose Francisco; Liu, Yu; Weng, Kuo-Chan; Robertson, Matthew J; Zhang, Shuxing; Prejusa, Allan; Harger, John; Tikhomirova, Dariya; Chopra, Mani; Iyer, Dinakar; Mercola, Mark; Oshima, Robert G; Willerson, James T; Potaman, Vladimir N; Schwartz, Robert J

    2012-08-01

    Unique insights for the reprograming of cell lineages have come from embryonic development in the ascidian Ciona, which is dependent upon the transcription factors Ci-ets1/2 and Ci-mesp to generate cardiac progenitors. We tested the idea that mammalian v-ets erythroblastosis virus E26 oncogene homolog 2 (ETS2) and mesoderm posterior (MESP) homolog may be used to convert human dermal fibroblasts into cardiac progenitors. Here we show that murine ETS2 has a critical role in directing cardiac progenitors during cardiopoiesis in embryonic stem cells. We then use lentivirus-mediated forced expression of human ETS2 to convert normal human dermal fibroblasts into replicative cells expressing the cardiac mesoderm marker KDR(+). However, although neither ETS2 nor the purported cardiac master regulator MESP1 can by themselves generate cardiac progenitors de novo from fibroblasts, forced coexpression of ETS2 and MESP1 or cell treatment with purified proteins reprograms fibroblasts into cardiac progenitors, as shown by the de novo appearance of core cardiac transcription factors, Ca(2+) transients, and sarcomeres. Our data indicate that ETS2 and MESP1 play important roles in a genetic network that governs cardiopoiesis. PMID:22826236

  2. Mutual modulation between norepinephrine and nitric oxide in haemocytes during the mollusc immune response

    PubMed Central

    Jiang, Qiufen; Zhou, Zhi; Wang, Lingling; Yang, Chuanyan; Wang, Jingjing; Wu, Tiantian; Song, Linsheng

    2014-01-01

    Nitric oxide (NO) is one of the most important immune molecules in innate immunity of invertebrates, and it can be regulated by norepinephrine in ascidian haemocytes. In the present study, the mutual modulation and underlying mechanism between norepinephrine and NO were explored in haemocytes of the scallop Chlamys farreri. After lipopolysaccharide stimulation, NO production increased to a significant level at 24 h, and norepinephrine concentration rose to remarkable levels at 3 h and 12~48 h. A significant decrease of NO production was observed in the haemocytes concomitantly stimulated with lipopolysaccharide and α-adrenoceptor agonist, while a dramatic increase of NO production was observed in the haemocytes incubated with lipopolysaccharide and β-adrenoceptor agonist. Meanwhile, the concentration of cyclic adenosine monophosphate (cAMP) decreased significantly in the haemocytes treated by lipopolysaccharide and α/β-adrenoceptor agonist, while the content of Ca2+ was elevated in those triggered by lipopolysaccharide and β-adrenoceptor agonist. When the haemocytes was incubated with NO donor, norepinephrine concentration was significantly enhanced during 1~24 h. Collectively, these results suggested that norepinephrine exerted varied effects on NO production at different immune stages via a novel α/β-adrenoceptor-cAMP/Ca2+ regulatory pattern, and NO might have a feedback effect on the synthesis of norepinephrine in the scallop haemocytes. PMID:25376551

  3. The specificity of the interaction between αB-crystallin and desmin filaments and its impact on filament aggregation and cell viability

    PubMed Central

    Elliott, Jayne L.; Der Perng, Ming; Prescott, Alan R.; Jansen, Karin A.; Koenderink, Gijsje H.; Quinlan, Roy A.

    2013-01-01

    CRYAB (αB-crystallin) is expressed in many tissues and yet the R120G mutation in CRYAB causes tissue-specific pathologies, namely cardiomyopathy and cataract. Here, we present evidence to demonstrate that there is a specific functional interaction of CRYAB with desmin intermediate filaments that predisposes myocytes to disease caused by the R120G mutation. We use a variety of biochemical and biophysical techniques to show that plant, animal and ascidian small heat-shock proteins (sHSPs) can interact with intermediate filaments. Nevertheless, the mutation R120G in CRYAB does specifically change that interaction when compared with equivalent substitutions in HSP27 (R140G) and into the Caenorhabditis elegans HSP16.2 (R95G). By transient transfection, we show that R120G CRYAB specifically promotes intermediate filament aggregation in MCF7 cells. The transient transfection of R120G CRYAB alone has no significant effect upon cell viability, although bundling of the endogenous intermediate filament network occurs and the mitochondria are concentrated into the perinuclear region. The combination of R120G CRYAB co-transfected with wild-type desmin, however, causes a significant reduction in cell viability. Therefore, we suggest that while there is an innate ability of sHSPs to interact with and to bind to intermediate filaments, it is the specific combination of desmin and CRYAB that compromises cell viability and this is potentially the key to the muscle pathology caused by the R120G CRYAB. PMID:23530264

  4. Rubritalea halochordaticola sp. nov., a carotenoid-producing verrucomicrobial species isolated from a marine chordate.

    PubMed

    Yoon, Jaewoo; Matsuda, Satoru; Adachi, Kyoko; Kasai, Hiroaki; Yokota, Akira

    2011-07-01

    A gram-negative-staining, obligately aerobic, non-motile, rod-shaped and chemoheterotrophic bacterium, designated strain MN1-1006(T), was isolated from an ascidian (sea squirt) sample, and was studied using a polyphasic taxonomic approach. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the new isolate shared approximately 93-99% sequence similarity with recognized species of the genus Rubritalea within the phylum 'Verrucomicrobia'. DNA-DNA hybridization values between strain MN1-1006(T) and Rubritalea squalenifaciens HOact23(T) and Rubritalea sabuli YM29-052(T) were 57% and 14.5%, respectively. Strain MN1-1006(T) produced carotenoid compounds that rendered the cell biomass a reddish pink colour. The strain also contained squalene. The cell-wall peptidoglycan of the novel strain contained muramic acid and meso-diaminopimelic acid. The DNA G+C content of strain MN1-1006(T) was 51.4 mol%. The major cellular fatty acids were iso-C(14:0), iso-C(16:0) and anteiso-C(15:0). The major isoprenoid quinone was MK-9. On the basis of these data, it was concluded that strain MN1-1006(T) represents a novel species of the genus Rubritalea, for which the name Rubritalea halochordaticola sp. nov. is proposed. The type strain is MN1-1006(T )( = KCTC 23186(T) = NBRC 107102(T)). PMID:20656813

  5. Biochemical and toxicological evaluation of nano-heparins in cell functional properties, proteasome activation and expression of key matrix molecules.

    PubMed

    Piperigkou, Zoi; Karamanou, Konstantina; Afratis, Nikolaos A; Bouris, Panagiotis; Gialeli, Chrysostomi; Belmiro, Celso L R; Pavão, Mauro S G; Vynios, Dimitrios H; Tsatsakis, Aristidis M

    2016-01-01

    The glycosaminoglycan heparin and its derivatives act strongly on blood coagulation, controlling the activity of serine protease inhibitors in plasma. Nonetheless, there is accumulating evidence highlighting different anticancer activities of these molecules in numerous types of cancer. Nano-heparins may have great biological significance since they can inhibit cell proliferation and invasion as well as inhibiting proteasome activation. Moreover, they can cause alterations in the expression of major modulators of the tumor microenvironment, regulating cancer cell behavior. In the present study, we evaluated the effects of two nano-heparin formulations: one isolated from porcine intestine and the other from the sea squirt Styela plicata, on a breast cancer cell model. We determined whether these nano-heparins are able to affect cell proliferation, apoptosis and invasion, as well as proteasome activity and the expression of extracellular matrix molecules. Specifically, we observed that nano-Styela compared to nano-Mammalian analogue has higher inhibitory role on cell proliferation, invasion and proteasome activity. Moreover, nano-Styela regulates cell apoptosis, expression of inflammatory molecules, such as IL-6 and IL-8 and reduces the expression levels of extracellular matrix macromolecules, such as the proteolytic enzymes MT1-MMP, uPA and the cell surface proteoglycans syndecan-1 and -2, but not on syndecan-4. The observations reported in the present article indicate that nano-heparins and especially ascidian heparin are effective agents for heparin-induced effects in critical cancer cell functions, providing an important possibility in pharmacological targeting. PMID:26476401

  6. Circadian clock in Ciona intestinalis revealed by microarray analysis and oxygen consumption.

    PubMed

    Minamoto, Toshifumi; Hanai, Shuji; Kadota, Koji; Oishi, Katsutaka; Matsumae, Hiromi; Fujie, Manabu; Azumi, Kaoru; Satoh, Noriyuki; Satake, Masanobu; Ishida, Norio

    2010-02-01

    The molecular mechanisms of the endogenous circadian clocks that allow most animals to adapt to environmental cycles have recently been uncovered. The draft genome of the ascidian, Ciona intestinalis, a model animal that is close to vertebrates, has been described. However, the C. intestinalis genome lacks the canonical clock genes such as Per, Bmal and Clock that are shared by vertebrates and insects. Here, we found the circadian rhythms at the physiological and molecular levels. The oxygen consumption rate was lower during the light phase and higher during the dark phase during a day, and the rhythm highly damped and continued under constant darkness. From the microarray analysis, the 396 spots (1.8% of the total; corresponding to 388 clones) were extracted as candidates for circadian expression. We confirmed the circadian expression of several candidate genes by northern blotting. Furthermore, three of four rhythmic expressed genes showed phase-shifts to prolonged light period. However, most of known clock genes did not oscillate. These data suggest that C. intestinalis have a unique molecular circadian clock and the daily environmental change is not such a strong effect for sea squirt in its evolution when compared to vertebrates and insects. PMID:19855119

  7. Global Diversity of Ascidiacea

    PubMed Central

    Shenkar, Noa; Swalla, Billie J.

    2011-01-01

    The class Ascidiacea presents fundamental opportunities for research in the fields of development, evolution, ecology, natural products and more. This review provides a comprehensive overview of the current knowledge regarding the global biodiversity of the class Ascidiacea, focusing in their taxonomy, main regions of biodiversity, and distribution patterns. Based on analysis of the literature and the species registered in the online World Register of Marine Species, we assembled a list of 2815 described species. The highest number of species and families is found in the order Aplousobranchia. Didemnidae and Styelidae families have the highest number of species with more than 500 within each group. Sixty percent of described species are colonial. Species richness is highest in tropical regions, where colonial species predominate. In higher latitudes solitary species gradually contribute more to the total species richness. We emphasize the strong association between species richness and sampling efforts, and discuss the risks of invasive species. Our inventory is certainly incomplete as the ascidian fauna in many areas around the world is relatively poorly known, and many new species continue to be discovered and described each year. PMID:21701684

  8. Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

    PubMed Central

    Kuete, Victor; Biavatti, Maique W

    2015-01-01

    Summary This review focuses on pyridoacridine-related metabolites as one biologically interesting group of alkaloids identified from marine sources. They are produced by marine sponges, ascidians and tunicates, and they are structurally comprised of four to eight fused rings including heterocycles. Acridine, acridone, dihydroacridine, and quinolone cores are features regularly found in these alkaloid skeletons. The lack of hydrogen atoms next to quaternary carbon atoms for two or three rings makes the chemical shift assignment a difficult task. In this regard, one of the aims of this review is the compilation of previously reported, pyridoacridine 13C NMR data. Observations have been made on the delocalization of electrons and the presence of some functional groups that lead to changes in the chemical shift of some carbon resonances. The lack of mass spectra information for these alkaloids due to the compactness of their structures is further discussed. Moreover, the biosynthetic pathways of some of these metabolites have been shown since they could inspire biomimetic synthesis. The synthesis routes used to prepare members of these marine alkaloids (as well as their analogues), which are synthesized for biological purposes are also discussed. Pyridoacridines were found to have a large spectrum of bioactivity and this review highlights and compares the pharmacophores that are responsible for the observed bioactivity. PMID:26664587

  9. CiMT-1, an unusual chordate metallothionein gene in Ciona intestinalis genome: structure and expression studies.

    PubMed

    Franchi, Nicola; Boldrin, Francesco; Ballarin, Loriano; Piccinni, Ester

    2011-02-01

    The present article reports on the characterization of the urochordate metallothionein (MT) gene, CiMT-1, from the solitary ascidian Ciona intestinalis. The predicted protein is shorter than other known deuterostome MTs, having only 39 amino acids. The gene has the same tripartite structure as vertebrate MTs, with some features resembling those of echinoderm MTs. The promoter region shows the canonical cis-acting elements recognized by transcription factors that respond to metal, ROS, and cytokines. Unusual sequences, described in fish and echinoderms, are also present. In situ hybridization suggests that only a population of hemocytes involved in immune responses, i.e. granular amebocytes, express CiMT-1 mRNA. These observations support the idea that urochordates perform detoxification through hemocytes, and that MTs may play important roles in inflammatory humoral responses in tunicates. The reported data offer new clues for better understanding the evolution of these multivalent proteins from non-vertebrate to vertebrate chordates and reinforce their functions in detoxification and immunity. PMID:21328559

  10. Cadmium effects in food chain experiments with marine plankton algae (dinophyta) and benthic filter feeders(Tunicata)

    NASA Astrophysics Data System (ADS)

    Kayser, H.

    The dinoflagellate Scrippsiella faeroense was grown in continuous flow-through cultures (10 1 turbidostat), the outflow leading into vessels containing tunicates of the species Ciona intestinalis, Ascidiella aspersa, Molgula manhattensi and Botryllus schlosseri. The culture medium consisted of natural sea water enriched only with N and P components. CdCl 2 was added to the system at sublethal concentrations. Algal growth wass affected at a Cd ++ concentration of 10 μg·1 -1; sublethal toxicity thresholds of the tunicates ranged from 5 to 10 μg·1 -1. Cadmium accumulation was much higer in the algae than in the tunicates; in spite of the continuous supply of relatively highly Cd contaminated algae, the Cd content of algae-fed tunicates increased insignificantly by comparison with unfed specimens. Only a small percentage of the Cd offered via the food algae was actually assimilated by the ascidians during the first 3 weeks of the experiment. Cd content of the tunicates remained almost constant for the next 2 weeks of the experiment, indicating that ingestion and excretion of the metal was at equilibrium. The concentration factor of Cd decreased through the trophic chain.

  11. LPS injection reprograms the expression and the 3' UTR of a CAP gene by alternative polyadenylation and the formation of a GAIT element in Ciona intestinalis.

    PubMed

    Vizzini, Aiti; Bonura, Angela; Longo, Valeria; Sanfratello, Maria Antonietta; Parrinello, Daniela; Cammarata, Matteo; Colombo, Paolo

    2016-09-01

    The diversification of cellular functions is one of the major characteristics of multicellular organisms which allow cells to modulate their gene expression, leading to the formation of transcripts and proteins with different functions and concentrations in response to different stimuli. CAP genes represent a widespread family of proteins belonging to the cysteine-rich secretory protein, antigen 5 and pathogenesis-related 1 superfamily which, it has been proposed, play key roles in the infection process and the modulation of immune responses in host animals. The ascidian Ciona intestinalis represents a group of proto-chordates with an exclusively innate immune system that has been widely studied in the field of comparative and developmental immunology. Using this biological system, we describe the identification of a novel APA mechanism by which an intronic polyadenylation signal is activated by LPS injection, leading to the formation of a shorter CAP mRNA capable of expressing the first CAP exon plus 19 amino acid residues whose sequence is contained within the first intron of the annotated gene. Furthermore, such an APA event causes the expression of a translational controlling cis-acting GAIT element which is not present in the previously isolated CAP isoform and identified in the 3'-UTR of other immune-related genes, suggesting an intriguing scenario in which both transcriptional and post-transcriptional control mechanisms are involved in the activation of the CAP gene during inflammatory response in C. intestinalis. PMID:27514009

  12. Enhancer of zeste acts as a major developmental regulator of Ciona intestinalis embryogenesis

    PubMed Central

    Le Goff, Emilie; Martinand-Mari, Camille; Martin, Marianne; Feuillard, Jérôme; Boublik, Yvan; Godefroy, Nelly; Mangeat, Paul; Baghdiguian, Stephen; Cavalli, Giacomo

    2015-01-01

    ABSTRACT The paradigm of developmental regulation by Polycomb group (PcG) proteins posits that they maintain silencing outside the spatial expression domains of their target genes, particularly of Hox genes, starting from mid embryogenesis. The Enhancer of zeste [E(z)] PcG protein is the catalytic subunit of the PRC2 complex, which silences its targets via deposition of the H3K27me3 mark. Here, we studied the ascidian Ciona intestinalis counterpart of E(z). Ci-E(z) is detected by immunohistochemistry as soon as the 2- and 4-cell stages as a cytoplasmic form and becomes exclusively nuclear thereafter, whereas the H3K27me3 mark is detected starting from the gastrula stage and later. Morpholino invalidation of Ci-E(z) leads to the total disappearance of both Ci-E(z) protein and its H3K27me3 mark. Ci-E(z) morphants display a severe phenotype. Strikingly, the earliest defects occur at the 4-cell stage with the dysregulation of cell positioning and mitotic impairment. At later stages, Ci-E(z)-deficient embryos are affected by terminal differentiation defects of neural, epidermal and muscle tissues, by the failure to form a notochord and by the absence of caudal nerve. These major phenotypic defects are specifically rescued by injection of a morpholino-resistant Ci-E(z) mRNA, which restores expression of Ci-E(z) protein and re-deposition of the H3K27me3 mark. As observed by qPCR analyses, Ci-E(z) invalidation leads to the early derepression of tissue-specific developmental genes, whereas late-acting developmental genes are generally down-regulated. Altogether, our results suggest that Ci-E(z) plays a major role during embryonic development in Ciona intestinalis by silencing early-acting developmental genes in a Hox-independent manner. PMID:26276097

  13. A single and rapid calcium wave at egg activation in Drosophila

    PubMed Central

    York-Andersen, Anna H.; Parton, Richard M.; Bi, Catherine J.; Bromley, Claire L.; Davis, Ilan; Weil, Timothy T.

    2015-01-01

    Activation is an essential process that accompanies fertilisation in all animals and heralds major cellular changes, most notably, resumption of the cell cycle. While activation involves wave-like oscillations in intracellular Ca2+ concentration in mammals, ascidians and polychaete worms and a single Ca2+ peak in fish and frogs, in insects, such as Drosophila, to date, it has not been shown what changes in intracellular Ca2+ levels occur. Here, we utilise ratiometric imaging of Ca2+ indicator dyes and genetically encoded Ca2+ indicator proteins to identify and characterise a single, rapid, transient wave of Ca2+ in the Drosophila egg at activation. Using genetic tools, physical manipulation and pharmacological treatments we demonstrate that the propagation of the Ca2+ wave requires an intact actin cytoskeleton and an increase in intracellular Ca2+ can be uncoupled from egg swelling, but not from progression of the cell cycle. We further show that mechanical pressure alone is not sufficient to initiate a Ca2+ wave. We also find that processing bodies, sites of mRNA decay and translational regulation, become dispersed following the Ca2+ transient. Based on this data we propose the following model for egg activation in Drosophila: exposure to lateral oviduct fluid initiates an increase in intracellular Ca2+ at the egg posterior via osmotic swelling, possibly through mechano-sensitive Ca2+ channels; a single Ca2+ wave then propagates in an actin dependent manner; this Ca2+ wave co-ordinates key developmental events including resumption of the cell cycle and initiation of translation of mRNAs such as bicoid. PMID:25750438

  14. An efficient method to find potentially universal population genetic markers, applied to metazoans

    PubMed Central

    2010-01-01

    Background Despite the impressive growth of sequence databases, the limited availability of nuclear markers that are sufficiently polymorphic for population genetics and phylogeography and applicable across various phyla restricts many potential studies, particularly in non-model organisms. Numerous introns have invariant positions among kingdoms, providing a potential source for such markers. Unfortunately, most of the few known EPIC (Exon Primed Intron Crossing) loci are restricted to vertebrates or belong to multigenic families. Results In order to develop markers with broad applicability, we designed a bioinformatic approach aimed at avoiding multigenic families while identifying intron positions conserved across metazoan phyla. We developed a program facilitating the identification of EPIC loci which allowed slight variation in intron position. From the Homolens databases we selected 29 gene families which contained 52 promising introns for which we designed 93 primer pairs. PCR tests were performed on several ascidians, echinoderms, bivalves and cnidarians. On average, 24 different introns per genus were amplified in bilaterians. Remarkably, five of the introns successfully amplified in all of the metazoan genera tested (a dozen genera, including cnidarians). The influence of several factors on amplification success was investigated. Success rate was not related to the phylogenetic relatedness of a taxon to the groups that most influenced primer design, showing that these EPIC markers are extremely conserved in animals. Conclusions Our new method now makes it possible to (i) rapidly isolate a set of EPIC markers for any phylum, even outside the animal kingdom, and thus, (ii) compare genetic diversity at potentially homologous polymorphic loci between divergent taxa. PMID:20836842

  15. Molecular evolution and in vitro characterization of Botryllus histocompatibility factor.

    PubMed

    Taketa, Daryl A; Nydam, Marie L; Langenbacher, Adam D; Rodriguez, Delany; Sanders, Erin; De Tomaso, Anthony W

    2015-10-01

    Botryllus schlosseri is a colonial ascidian with a natural ability to anastomose with another colony to form a vascular and hematopoietic chimera. In order to fuse, two individuals must share at least one allele at the highly polymorphic fuhc locus. Otherwise, a blood-based inflammatory response will occur resulting in a melanin scar at the sites of interaction. The single-locus genetic control of allorecognition makes B. schlosseri an attractive model to study the underlying molecular mechanisms. Over the past decade, several candidate genes involved in allorecognition have been identified, but how they ultimately contribute to allorecognition outcome remains poorly understood. Here, we report our initial molecular characterization of a recently identified candidate allodeterminant called Botryllus histocompatibility factor (bhf). bhf, both on a DNA and protein level, is the least polymorphic protein in the fuhc locus studied so far and, unlike other known allorecognition determinants, does not appear to be under any form of balancing or directional selection. Additionally, we identified a second isoform through mRNA-Seq and an EST assembly library which is missing exon 3, resulting in a C-terminally truncated form. We report via whole-mount fluorescent in situ hybridization that a subset of cells co-express bhf and cfuhc(sec). Finally, we observed BHF's localization in HEK293T at the cytoplasmic side of the plasma membrane in addition to the nucleus via a nuclear localization signal. Given the localization data thus far, we hypothesize that BHF may function as a scaffolding protein in a complex with other Botryllus proteins, rather than functioning as an allorecognition determinant. PMID:26359175

  16. Morphological Differences between Larvae of the Ciona intestinalis Species Complex: Hints for a Valid Taxonomic Definition of Distinct Species

    PubMed Central

    Pennati, Roberta; Ficetola, Gentile Francesco; Brunetti, Riccardo; Caicci, Federico; Gasparini, Fabio; Griggio, Francesca; Sato, Atsuko; Stach, Thomas; Kaul-Strehlow, Sabrina; Gissi, Carmela; Manni, Lucia

    2015-01-01

    The cosmopolitan ascidian Ciona intestinalis is the most common model species of Tunicata, the sister-group of Vertebrata, and widely used in developmental biology, genomics and evolutionary studies. Recently, molecular studies suggested the presence of cryptic species hidden within the C. intestinalis species, namely C. intestinalis type A and type B. So far, no substantial morphological differences have been identified between individuals belonging to the two types. Here we present morphometric, immunohistochemical, and histological analyses, as well as 3-D reconstructions, of late larvae obtained by cross-fertilization experiments of molecularly determined type A and type B adults, sampled in different seasons and in four different localities. Our data point to quantitative and qualitative differences in the trunk shape of larvae belonging to the two types. In particular, type B larvae exhibit a longer pre-oral lobe, longer and relatively narrower total body length, and a shorter ocellus-tail distance than type A larvae. All these differences were found to be statistically significant in a Discriminant Analysis. Depending on the number of analyzed parameters, the obtained discriminant function was able to correctly classify > 93% of the larvae, with the remaining misclassified larvae attributable to the existence of intra-type seasonal variability. No larval differences were observed at the level of histology and immunohistochemical localization of peripheral sensory neurons. We conclude that type A and type B are two distinct species that can be distinguished on the basis of larval morphology and molecular data. Since the identified larval differences appear to be valid diagnostic characters, we suggest to raise both types to the rank of species and to assign them distinct names. PMID:25955391

  17. Chordate betagamma-crystallins and the evolutionary developmental biology of the vertebrate lens.

    PubMed

    Riyahi, Kumars; Shimeld, Sebastian M

    2007-07-01

    Several animal lineages, including the vertebrates, have evolved sophisticated eyes with lenses that refract light to generate an image. The nearest invertebrate relatives of the vertebrates, such as the ascidians (sea squirts) and amphioxus, have only basic light detecting organs, leading to the widely-held view that the vertebrate lens is an innovation that evolved in early vertebrates. From an embryological perspective the lens is different from the rest of the eye, in that the eye is primarily of neural origin while the lens derives from a non-neural ectodermal placode which invaginates into the developing eye. How such an organ could have evolved has attracted much speculation. Recently, however, molecular developmental studies of sea squirts have started to suggest a possible evolutionary origin for the lens. First, studies of the Pax, Six, Eya and other gene families have indicated that sea squirts have areas of non-neural ectoderm homologous to placodes, suggesting an origin for the embryological characteristics of the lens. Second, the evolution and regulation of the betagamma-crystallins has been studied. These form one of the key crystallin gene families responsible for the transparency of the lens, and regulatory conservation between the betagamma-crystallin gene in the sea squirt Ciona intestinalis and the vertebrate visual system has been experimentally demonstrated. These data, together with knowledge of the morphological, physiological and gene expression similarities between the C. intestinalis ocellus and vertebrate retina, have led us to propose a hypothesis for the evolution of the vertebrate lens and integrated vertebrate eye via the co-option and combination of ancient gene regulatory networks; one controlling morphogenetic aspects of lens development and one controlling the expression of a gene family responsible for the biophysical properties of the lens, with the components of the retina having evolved from an ancestral photoreceptive organ

  18. Widespread occurrence of an intranuclear bacterial parasite in vent and seep bathymodiolin mussels.

    PubMed

    Zielinski, Frank U; Pernthaler, Annelie; Duperron, Sébastien; Raggi, Luciana; Giere, Olav; Borowski, Christian; Dubilier, Nicole

    2009-05-01

    Many parasitic bacteria live in the cytoplasm of multicellular animals, but only a few are known to regularly invade their nuclei. In this study, we describe the novel bacterial parasite "Candidatus Endonucleobacter bathymodioli" that invades the nuclei of deep-sea bathymodiolin mussels from hydrothermal vents and cold seeps. Bathymodiolin mussels are well known for their symbiotic associations with sulfur- and methane-oxidizing bacteria. In contrast, the parasitic bacteria of vent and seep animals have received little attention despite their potential importance for deep-sea ecosystems. We first discovered the intranuclear parasite "Ca. E. bathymodioli" in Bathymodiolus puteoserpentis from the Logatchev hydrothermal vent field on the Mid-Atlantic Ridge. Using primers and probes specific to "Ca. E. bathymodioli" we found this intranuclear parasite in at least six other bathymodiolin species from vents and seeps around the world. Fluorescence in situ hybridization and transmission electron microscopy analyses of the developmental cycle of "Ca. E. bathymodioli" showed that the infection of a nucleus begins with a single rod-shaped bacterium which grows to an unseptated filament of up to 20 microm length and then divides repeatedly until the nucleus is filled with up to 80,000 bacteria. The greatly swollen nucleus destroys its host cell and the bacteria are released after the nuclear membrane bursts. Intriguingly, the only nuclei that were never infected by "Ca. E. bathymodioli" were those of the gill bacteriocytes. These cells contain the symbiotic sulfur- and methane-oxidizing bacteria, suggesting that the mussel symbionts can protect their host nuclei against the parasite. Phylogenetic analyses showed that the "Ca. E. bathymodioli" belongs to a monophyletic clade of Gammaproteobacteria associated with marine metazoans as diverse as sponges, corals, bivalves, gastropods, echinoderms, ascidians and fish. We hypothesize that many of the sequences from this clade

  19. Nimbus (BgI): An active non-LTR retrotransposon of the Schistosoma mansoni snail host Biomphalaria glabrata✰

    PubMed Central

    Raghavan, Nithya; Tettelin, Hervé; Miller, André; Hostetler, Jessica; Tallon, Luke; Knight, Matty

    2009-01-01

    The freshwater snail Biomphalaria glabrata is closely associated with the transmission of human schistosomiasis. An ecologically sound method has been proposed to control schistosomiasis using genetically modified snails to displace endemic, susceptible ones. To assess the viability of this form of biological control, studies towards understanding the molecular makeup of the snail relative to the presence of endogenous mobile genetic elements are being undertaken since they can be exploited for genetic transformation studies. We previously cloned a 1.95 Kb BamHI fragment in B. glabrata (BGR2) with sequence similarity to the human long interspersed nuclear element (LINE or L1). A contiguous, full-length sequence corresponding to BGR2, hereafter-named nimbus (BgI), has been identified from a B. glabrata bacterial artificial chromosome (BAC) library. Sequence analysis of the 65,764 bp BAC insert contained one full-length, complete nimbus (BgI) element (element I), two full-length elements (elements II and III) containing deletions and flanked by target site duplications and 10 truncated copies. The intact nimbus (BgI) contained two open reading frames (ORFs 1 and 2) encoding the characteristic hallmark domains found in non-long terminal repeat retrotransposons belonging to the I clade; a nucleic acid binding protein in ORF1 and an apurinic/apyrimidinic endonuclease, reverse transcriptase and RNase H in ORF2. Phylogenetic analysis revealed that nimbus (BgI) is closely related to Drosophila (I factor), mosquito Aedes aegypti (MosquI) and chordate ascidian Ciona intestinalis (CiI) retrotransposons. Nimbus (BgI) represents the first complete mobile element characterized from a mollusk that appears to be transcriptionally active and is widely distributed in snails of the neotropics and the Old World. PMID:17521654

  20. Deep-water stands of Cystoseira zosteroides C. Agardh (Fucales, Ochrophyta) in the Northwestern Mediterranean: Insights into assemblage structure and population dynamics

    NASA Astrophysics Data System (ADS)

    Ballesteros, Enric; Garrabou, Joaquim; Hereu, Bernat; Zabala, Mikel; Cebrian, Emma; Sala, Enric

    2009-04-01

    Populations dominated by Cystoseira zosteroides, an endemic and threatened Mediterranean seaweed, colonize deep-water rocky habitats down to more than 50 m depth. Assemblages dominated by this species display high algal and invertebrate species richness. Algal biomass averages 1134 g dw m -2. Erect and turf algae account for only 25% of total algal dry weight, while encrusting corallines are responsible for the remaining 75%. Sponges, bryozoans and ascidians constitute the dominant sessile macrofauna. Cystoseira zosteroides is the dominant erect algae, with a mean biomass of 60.6 g dw m -2, and densities ranging from 4 to 7 plants m -2. The alien turf alga Womersleyella setacea has a biomass of 104.2 g dw m -2 and covers most of the understory substrate. The size-frequency distribution of C. zosteroides populations shows differences over time. Mean annual growth of the main axis is around 0.5 cm and mean annual mortality rate is lower than 2%. Recruitment was almost nil during the studied period of time (10 years). Processes structuring these deep-water Cystoseira stands must be driven by episodic disturbances, after-disturbance recruitment pulses, and long periods of steady growth that last at least 10 years. However, it is also possible that recruitment is irreversibly inhibited by the alien alga W. setacea in which case these old-growth stands are faced with extinction. The highly diversified assemblages and the low growth and low mortality rates of C. zosteroides indicate high vulnerability to natural and anthropogenic disturbances, and call for effective measures to ensure their conservation.

  1. Unusual Symbiotic Cyanobacteria Association in the Genetically Diverse Intertidal Marine Sponge Hymeniacidon perlevis (Demospongiae, Halichondrida)

    PubMed Central

    Alex, Anoop; Vasconcelos, Vitor; Tamagnini, Paula; Santos, Arlete; Antunes, Agostinho

    2012-01-01

    Cyanobacteria represent one of the most common members of the sponge-associated bacterial community and are abundant symbionts of coral reef ecosystems. In this study we used Transmission Electron Microscopy (TEM) and molecular techniques (16S rRNA gene marker) to characterize the spatial distribution of cyanobionts in the widely dispersed marine intertidal sponge Hymeniacidon perlevis along the coast of Portugal (Atlantic Ocean). We described new sponge associated cyanobacterial morphotypes (Xenococcus-like) and we further observed Acaryochloris sp. as a sponge symbiont, previously only reported in association with ascidians. Besides these two unique cyanobacteria, H. perlevis predominantly harbored Synechococcus sp. and uncultured marine cyanobacteria. Our study supports the hypothesis that the community of sponge cyanobionts varies irrespective of the geographical location and is likely influenced by seasonal fluctuations. The observed multiple cyanobacterial association among sponges of the same host species over a large distance may be attributed to horizontal transfer of symbionts. This may explain the absence of a co-evolutionary pattern between the sponge host and its symbionts. Finally, in spite of the short geographic sampling distance covered, we observed an unexpected high intra-specific genetic diversity in H. perlevis using the mitochondrial genes ATP6 (π = 0.00177), COI (π = 0.00241) and intergenic spacer SP1 (π = 0.00277) relative to the levels of genetic variation of marine sponges elsewhere. Our study suggests that genotypic variation among the sponge host H. perlevis and the associated symbiotic cyanobacteria diversity may be larger than previously recognized. PMID:23251637

  2. On the Origin and Evolution of Vertebrate Olfactory Receptor Genes: Comparative Genome Analysis Among 23 Chordate Species

    PubMed Central

    2009-01-01

    Olfaction is a primitive sense in organisms. Both vertebrates and insects have receptors for detecting odor molecules in the environment, but the evolutionary origins of these genes are different. Among studied vertebrates, mammals have ∼1,000 olfactory receptor (OR) genes, whereas teleost fishes have much smaller (∼100) numbers of OR genes. To investigate the origin and evolution of vertebrate OR genes, I attempted to determine near-complete OR gene repertoires by searching whole-genome sequences of 14 nonmammalian chordates, including cephalochordates (amphioxus), urochordates (ascidian and larvacean), and vertebrates (sea lamprey, elephant shark, five teleost fishes, frog, lizard, and chicken), followed by a large-scale phylogenetic analysis in conjunction with mammalian OR genes identified from nine species. This analysis showed that the amphioxus has >30 vertebrate-type OR genes though it lacks distinctive olfactory organs, whereas all OR genes appear to have been lost in the urochordate lineage. Some groups of genes (θ, κ, and λ) that are phylogenetically nested within vertebrate OR genes showed few gene gains and losses, which is in sharp contrast to the evolutionary pattern of OR genes, suggesting that they are actually non-OR genes. Moreover, the analysis demonstrated a great difference in OR gene repertoires between aquatic and terrestrial vertebrates, reflecting the necessity for the detection of water-soluble and airborne odorants, respectively. However, a minor group (β) of genes that are atypically present in both aquatic and terrestrial vertebrates was also found. These findings should provide a critical foundation for further physiological, behavioral, and evolutionary studies of olfaction in various organisms. PMID:20333175

  3. Screening of ovarian steroidogenic pathway in Ciona intestinalis and its modulation after tributyltin exposure

    SciTech Connect

    Cangialosi, Maria Vittoria; Puccia, Egidio; Mazzola, Antonio; Mansueto, Valentina; Arukwe, Augustine

    2010-05-15

    In this study, we have identified several ovarian steroids in Ciona with high similarity to vertebrate steroids and showed that cholesterol, corticosterone, dehydroepiandrosterone, estrone, estradiol-17beta, testosterone, pregnenolone, progesterone, have identical molecular spectra with vertebrate steroids. In addition, we have studied the effects of an endocrine disruptor (tributyltin: TBT) on these sex hormones and their precursors, ovarian morphology, and gene expression of some key enzymes in steroidogenic pathway in the ovary of Ciona. Ovarian specimens were cultured in vitro using different concentrations of TBT (10{sup -5}, 10{sup -4} and 10{sup -3} M). Ethanol was used as solvent control. Gene expression analysis was performed for adrenodoxin (ADREN) and adrenodoxin reductase (ADOX) (mediators of acute steroidogenesis) and 17beta-hydroxysteroid dehydrogenase (17beta-HSD). These transcripts were detected and measured by quantitative (real-time) polymerase chain reaction (qPCR). Sex steroids and their precursors were identified and quantified by a gas chromatography-mass spectroscopy (GC-MS) method. Exposure of Ciona ovaries to TBT produced modulations (either increased or decreased) of sterols and sex steroid levels, whereas no significant differences in ADREN, ADOX or 17beta-HSD mRNA expression patterns were observed. Histological analysis shows that TBT produced several modifications on Ciona ovarian morphology that includes irregular outline of nuclear membrane, less compacted cytoplasm, in addition to test and granulosa cells that were detached from the oocyte membrane. Given that the ascidians represent very simple experimental models for the study of endocrine disruption by environmental contaminants, our findings provide excellent models for multiple identification and quantification of sex steroid and their precursors in biological samples exposed to endocrine-disrupting chemicals and for direct extrapolation of such effects across taxonomic groups

  4. Evolution of neural crest and placodes: amphioxus as a model for the ancestral vertebrate?

    NASA Technical Reports Server (NTRS)

    Holland, L. Z.; Holland, N. D.

    2001-01-01

    Recent studies of protochordates (ascidian tunicates and amphioxus) have given insights into possible ancestors of 2 of the characteristic features of the vertebrate head: neural crest and placodes. The neural crest probably evolved from cells on either side of the neural plate-epidermis boundary in a protochordate ancestral to the vertebrates. In amphioxus, homologues of several vertebrate neural crest marker genes (BMP2/4, Pax3/7, Msx, Dll and Snail) are expressed at the edges of the neural plate and/or adjacent nonneural ectoderm. Some of these markers are also similarly expressed in tunicates. In protochordates, however, these cells, unlike vertebrate neural crest, neither migrate as individuals through embryonic tissues nor differentiate into a wide spectrum of cell types. Therefore, while the protochordate ancestor of the vertebrates probably had the beginnings of a genetic programme for neural crest formation, this programme was augmented in the earliest vertebrates to attain definitive neural crest. Clear homologues of vertebrate placodes are lacking in protochordates. However, both amphioxus and tunicates have ectodermal sensory cells. In tunicates these are all primary neurons, sending axons to the central nervous system, while in amphioxus, the ectodermal sensory cells include both primary neurons and secondary neurons lacking axons. Comparisons of developmental gene expression suggest that the anterior ectoderm in amphioxus may be homologous to the vertebrate olfactory placode, the only vertebrate placode with primary, not secondary, neurons. Similarly, biochemical, morphological and gene expression data suggest that amphioxus and tunicates also have homologues of the adenohypophysis, one of the few vertebrate structures derived from nonneurogenic placodes. In contrast, the origin of the other vertebrate placodes is very uncertain.

  5. Environmental Evolution of a Small Antarctic Fjord Through the Recent Past

    NASA Astrophysics Data System (ADS)

    Hass, H. C.; Wölfl, A. C.; Wittenberg, N.; Betzler, C.; Kuhn, G.

    2014-12-01

    Rapid regional warming at an increasing pace ever since the end of the Little Ice Age (c. AD 1900) causes significant change in the coastal marine environments of the West Antarctic Peninsula and beyond. A comprehensive set of hydroacoustic ground-discrimination data (RoxAnn GDX) was gathered to develop a high resolution characterization of the seafloor habitats in the Potter Cove, King George Island, a small fjord with a retreating former tidewater glacier at its head. Sediment samples and underwater video footage are used for ground truthing. Seven habitat zones are distinguished. These include the shallow high-energy wave zone exposing unvegetated rocks to the low-energy deeper basins characterized by muddy sediments and the typical biota including ophiuroids, ascidians, sponges, sea pens. The results allow to subdivide the Potter Cove into a "dynamic zone" (DZ) with rocks and mixed fine sediments covering the inner cove, a large transition zone that we call the "subrecent zone" (SZ) buried under fine meltwater sediments and the "quasi persistent zone" (QPZ) that reveals more mature conditions in many aspects further downfjord. These zones represent development stages resulting from the increasing distance to and decreasing influence of the glacier front. The DZ is trailing directly behind the retreating glacier front. As long as there is strong discharge of sediment-loaded meltwater the DZ transitions into the SZ after a period of time (under recent conditions: decades) which itself transitions into the QPZ after centuries. We assume that during the Medieval Warm Period (c. AD 800-1350) the glacier terminus was at or even behind its present position. Until the maximum of the Little Ice Age the glacier advanced to form a prominent moraine complex. Ever since the glacier retreated at increasing speed to its recent position. If the warming trend continues the glacier will retreat further away from the fjord head and the QPZ will likely cover the entire fjord after

  6. Biofouling of inlet pipes affects water quality in running seawater aquaria and compromises sponge cell proliferation.

    PubMed

    Alexander, Brittany E; Mueller, Benjamin; Vermeij, Mark J A; van der Geest, Harm H G; de Goeij, Jasper M

    2015-01-01

    Marine organism are often kept, cultured, and experimented on in running seawater aquaria. However, surprisingly little attention is given to the nutrient composition of the water flowing through these systems, which is generally assumed to equal in situ conditions, but may change due to the presence of biofouling organisms. Significantly lower bacterial abundances and higher inorganic nitrogen species (nitrate, nitrite, and ammonium) were measured in aquarium water when biofouling organisms were present within a 7-year old inlet pipe feeding a tropical reef running seawater aquaria system, compared with aquarium water fed by a new, biofouling-free inlet pipe. These water quality changes are indicative of the feeding activity and waste production of the suspension- and filter-feeding communities found in the old pipe, which included sponges, bivalves, barnacles, and ascidians. To illustrate the physiological consequences of these water quality changes on a model organism kept in the aquaria system, we investigated the influence of the presence and absence of the biofouling community on the functioning of the filter-feeding sponge Halisarca caerulea, by determining its choanocyte (filter cell) proliferation rates. We found a 34% increase in choanocyte proliferation rates following the replacement of the inlet pipe (i.e., removal of the biofouling community). This indicates that the physiological functioning of the sponge was compromised due to suboptimal food conditions within the aquarium resulting from the presence of the biofouling organisms in the inlet pipe. This study has implications for the husbandry and performance of experiments with marine organisms in running seawater aquaria systems. Inlet pipes should be checked regularly, and replaced if necessary, in order to avoid excessive biofouling and to approach in situ water quality. PMID:26664799

  7. Biofouling of inlet pipes affects water quality in running seawater aquaria and compromises sponge cell proliferation

    PubMed Central

    Mueller, Benjamin; Vermeij, Mark J.A.; van der Geest, Harm H.G.

    2015-01-01

    Marine organism are often kept, cultured, and experimented on in running seawater aquaria. However, surprisingly little attention is given to the nutrient composition of the water flowing through these systems, which is generally assumed to equal in situ conditions, but may change due to the presence of biofouling organisms. Significantly lower bacterial abundances and higher inorganic nitrogen species (nitrate, nitrite, and ammonium) were measured in aquarium water when biofouling organisms were present within a 7-year old inlet pipe feeding a tropical reef running seawater aquaria system, compared with aquarium water fed by a new, biofouling-free inlet pipe. These water quality changes are indicative of the feeding activity and waste production of the suspension- and filter-feeding communities found in the old pipe, which included sponges, bivalves, barnacles, and ascidians. To illustrate the physiological consequences of these water quality changes on a model organism kept in the aquaria system, we investigated the influence of the presence and absence of the biofouling community on the functioning of the filter-feeding sponge Halisarca caerulea, by determining its choanocyte (filter cell) proliferation rates. We found a 34% increase in choanocyte proliferation rates following the replacement of the inlet pipe (i.e., removal of the biofouling community). This indicates that the physiological functioning of the sponge was compromised due to suboptimal food conditions within the aquarium resulting from the presence of the biofouling organisms in the inlet pipe. This study has implications for the husbandry and performance of experiments with marine organisms in running seawater aquaria systems. Inlet pipes should be checked regularly, and replaced if necessary, in order to avoid excessive biofouling and to approach in situ water quality. PMID:26664799

  8. An assessment of contamination of the Fusaro Lagoon (Campania Province, southern Italy) by trace metals.

    PubMed

    Arienzo, M; Toscano, F; Di Fraia, M; Caputi, L; Sordino, P; Guida, M; Aliberti, F; Ferrara, L

    2014-09-01

    The Fusaro Lagoon is a shallow lagoon, located in SW Italy, largely influenced in the last decades by several anthropic impacts. The study examined the pollution status of the lagoon, during year 2011-2012 at nine sampling stations with the aim to find out proper measurements of water lagoon restoration. Concentrations of heavy metals (HMs) (aluminium [Al], barium [Ba], cadmium [Cd], copper [Cu], iron [Fe], manganese [Mn], vanadium [V] and zinc [Zn]) were examined in water, sediments and specimens of the ascidian Ciona intestinalis sp. A. Low levels of dissolved oxygen concentration were detected at many stations, with mean values of 5.2-6.4 mg L(-1). The redox potential of surface waters was also low, -2.7 to 50.7 mV. Sediments possessed high organic matter content, 17.7-29.4%. In sediments, the mean Zn level, 251.4 mg kg(-1), was about sixfold higher than that recorded in year 2000 (38.5 mg kg(-1)) and considerably higher than that recorded in 2007 (191 mg kg(-1)). The mean levels of Cd were outstandingly high, with a mean value of 70.5 mg kg(-1), about 30- and 50-fold higher than those determined in 2000 and 2007, respectively. Cadmium (Cd), Cu and nickel (Ni) appeared in excess with respect to most current guidelines, reaching significant pollution levels. C. intestinalis sp. A was detected only at few stations, with metals accumulated preferentially in the body in respect to the tunic, from 1.2 times for Zn (178 mg kg(-1)) to 4.0 times for V (304 mg kg(-1)). Data suggests the necessity of an immediate action of eco-compatible interventions for environmental restoration. PMID:24865384

  9. Tolerance of Sponge Assemblages to Temperature Anomalies: Resilience and Proliferation of Sponges following the 1997–8 El-Niño Southern Oscillation

    PubMed Central

    Kelmo, Francisco; Bell, James J.; Attrill, Martin J.

    2013-01-01

    Coral reefs across the world are under threat from a range of stressors, and while there has been considerable focus on the impacts of these stressors on corals, far less is known about their effect on other reef organisms. The 1997–8 El-Niño Southern Oscillation (ENSO) had notable and severe impacts on coral reefs worldwide, but not all reef organisms were negatively impacted by this large-scale event. Here we describe how the sponge fauna at Bahia, Brazil was influenced by the 1997–8 ENSO event. Sponge assemblages from three contrasting reef habitats (reef tops, walls and shallow banks) at four sites were assessed annually from 1995 to 2011. The within-habitat sponge diversity did not vary significantly across the study period; however, there was a significant increase in density in all habitats. Multivariate analyses revealed no significant difference in sponge assemblage composition (ANOSIM) between pre- and post-ENSO years for any of the habitats, suggesting that neither the 1997–8 nor any subsequent smaller ENSO events have had any measurable impact on the reef sponge assemblage. Importantly, this is in marked contrast to the results previously reported for a suite of other taxa (including corals, echinoderms, bryozoans, and ascidians), which all suffered mass mortalities as a result of the ENSO event. Our results suggest that of all reef taxa, sponges have the potential to be resilient to large-scale thermal stress events and we hypothesize that sponges might be less affected by projected increases in sea surface temperature compared to other major groups of reef organisms. PMID:24116109

  10. VacuSIP, an Improved InEx Method for In Situ Measurement of Particulate and Dissolved Compounds Processed by Active Suspension Feeders.

    PubMed

    Morganti, Teresa; Yahel, Gitai; Ribes, Marta; Coma, Rafel

    2016-01-01

    Benthic suspension feeders play essential roles in the functioning of marine ecosystems. By filtering large volumes of water, removing plankton and detritus, and excreting particulate and dissolved compounds, they serve as important agents for benthic-pelagic coupling. Accurately measuring the compounds removed and excreted by suspension feeders (such as sponges, ascidians, polychaetes, bivalves) is crucial for the study of their physiology, metabolism, and feeding ecology, and is fundamental to determine the ecological relevance of the nutrient fluxes mediated by these organisms. However, the assessment of the rate by which suspension feeders process particulate and dissolved compounds in nature is restricted by the limitations of the currently available methodologies. Our goal was to develop a simple, reliable, and non-intrusive method that would allow clean and controlled water sampling from a specific point, such as the excurrent aperture of benthic suspension feeders, in situ. Our method allows simultaneous sampling of inhaled and exhaled water of the studied organism by using minute tubes installed on a custom-built manipulator device and carefully positioned inside the exhalant orifice of the sampled organism. Piercing a septum on the collecting vessel with a syringe needle attached to the distal end of each tube allows the external pressure to slowly force the sampled water into the vessel through the sampling tube. The slow and controlled sampling rate allows integrating the inherent patchiness in the water while ensuring contamination free sampling. We provide recommendations for the most suitable filtering devices, collection vessel, and storing procedures for the analyses of different particulate and dissolved compounds. The VacuSIP system offers a reliable method for the quantification of undisturbed suspension feeder metabolism in natural conditions that is cheap and easy to learn and apply to assess the physiology and functional role of filter

  11. Impact and recovery from a mass mortality event of the gorgonian Paramuricea clavata populations on the french Mediterranean coasts

    NASA Astrophysics Data System (ADS)

    Bonhomme, D.; Garrabou, J.; Perez, T.; Sartoretto, S.; Harmelin, J. G.

    2003-04-01

    An unprecedented mass mortality occurred in the NW Mediterranean in summer 1999. This event affected 30 species of invertebrates from 5 different Phyla (sponges, cnidarians, molluscs, ascidians, bryozoans) on several hundred kilometres of shoreline from the Bay of Genoa in Italy to the Bay of Marseilles in France. The most affected taxa were sponges and cnidarians. This mass mortality took place under an unusual environmental context characterized by high and stable water column temperatures. The impact of the mass mortality and recovery (1999-2002) of populations of the gorgonian Paramuricea clavata from Provence's coasts (France) have been studied. Most surveyed populations displayed 50 % of affected colonies at different degree (dead, severe and low damage), although a great variability in rates of mortality and tissue loss was also evident depending among sites. The mortality impact decreased with depth, a pattern which supports the hypothesis that temperature played a key role in this event. Surveys on populations for which pre-mortality data (density and size structure) was attested that recovery was far from completion three years after the mortality. Considering the growth rate of P. clavata, full recovery of the most affected local populations will take several decades will be necessary to return to pre-mortality values. In the context of the global change and taking into account the correlation with the temperature, one may expect that the frequency of of these kind of events will increase in the next decades. Dramatic consequences can be expected for the conservation of the affected species in shallow habitats, in particular, and for the Mediterranean biodiversity, in general.

  12. Short-term post-mortality predation and scavenging and longer-term recovery after anoxia in the northern Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Blasnig, M.; Riedel, B.; Zuschin, M.; Schiemer, L.; Stachowitsch, M.

    2013-03-01

    In the Mediterranean, the northern Adriatic Sea shows most features known to promote late-summer hypoxia and anoxia. These features, along with anthropogenic eutrophication and marine snow events, have led to repeated benthic mortalities here. The present study was designed to document the post-anoxia macrofauna dynamics. We deployed an underwater instrument to induce small-scale anoxia in situ (total area 0.5 m2). Two time-lapse camera deployments examined short-term scavenging of the moribund and dead organisms (multi-species clumps consisting of sponges and ascidians) over a 3-day period (August 2008: 71.5 h, September 2008: 67.5 h). Longer-term recovery (2 yr) in the same two plots was examined with an independent photo-series. Predators and scavengers arrived in a distinct sequence. The first to arrive were demersal (Gobius niger, Serranus hepatus) and benthopelagic fishes (Diplodus vulgaris, Pagellus erythrinus), followed by hermit crabs (Paguristes eremita, showing a clear day/night rhythm in presence) and gastropods (Hexaplex trunculus). This sequence of arrival is attributed to the relative speeds of the organisms and their densities. The scavengers remained in dense aggregations (e.g. up to 33 P. eremita individuals at one time) as long as the dead organisms were available. The whole sessile fauna was largely removed or consumed within 7 (August plot) and 13 (September plot) days after anoxia. No macroepibenthic recovery took place in the experimental plots one and two years after anoxia. This study underlines the sensitivity of this soft-bottom community and supports calls for reducing additional anthropogenic disturbances such as damaging commercial fishing practices that impede recolonization and threaten benthic community structure and function over the long-term.

  13. Marine Natural Products Acting on the Acetylcholine-Binding Protein and Nicotinic Receptors: From Computer Modeling to Binding Studies and Electrophysiology

    PubMed Central

    Kudryavtsev, Denis; Makarieva, Tatyana; Utkina, Natalia; Santalova, Elena; Kryukova, Elena; Methfessel, Christoph; Tsetlin, Victor; Stonik, Valentin; Kasheverov, Igor

    2014-01-01

    For a small library of natural products from marine sponges and ascidians, in silico docking to the Lymnaea stagnalis acetylcholine-binding protein (AChBP), a model for the ligand-binding domains of nicotinic acetylcholine receptors (nAChRs), was carried out and the possibility of complex formation was revealed. It was further experimentally confirmed via competition with radioiodinated α-bungarotoxin ([125I]-αBgt) for binding to AChBP of the majority of analyzed compounds. Alkaloids pibocin, varacin and makaluvamines С and G had relatively high affinities (Ki 0.5–1.3 μM). With the muscle-type nAChR from Torpedo californica ray and human neuronal α7 nAChR, heterologously expressed in the GH4C1 cell line, no competition with [125I]-αBgt was detected in four compounds, while the rest showed an inhibition. Makaluvamines (Ki ~ 1.5 μM) were the most active compounds, but only makaluvamine G and crambescidine 359 revealed a weak selectivity towards muscle-type nAChR. Rhizochalin, aglycone of rhizochalin, pibocin, makaluvamine G, monanchocidin, crambescidine 359 and aaptamine showed inhibitory activities in electrophysiology experiments on the mouse muscle and human α7 nAChRs, expressed in Xenopus laevis oocytes. Thus, our results confirm the utility of the modeling studies on AChBPs in a search for natural compounds with cholinergic activity and demonstrate the presence of the latter in the analyzed marine biological sources. PMID:24686559

  14. Direct effects of physical stress can be counteracted by indirect benefits: oyster growth on a tidal elevation gradient.

    PubMed

    Bishop, Melanie J; Peterson, Charles H

    2006-03-01

    The paradigmatic gradient for intertidal marine organisms of increasing physical stress from low to high elevation has long served as the basis for using direct effects of duration of water coverage to predict many biological patterns. Accordingly, changes in potential feeding time may predict the direction and magnitude of differences between elevations in individual growth rates of sessile marine invertebrates. Oysters (triploid Crassostrea ariakensis) experimentally introduced at intertidal (MLW+0.05 m) and subtidal (MLW-0.25 m) elevations in racks provided a test of the ability to use duration of water coverage to predict changes in growth. During early-to-mid winter, a depression of 38-47% in shell growth of intertidal oysters matched the 36% reduction in available feeding time relative to subtidal oysters. In late winter as solar heating of exposed oysters increased, growth differences of 52-55% departed only slightly from the predicted 39%. In spring, however, duration of water coverage failed to predict even the correct direction of growth change with elevation as intertidal oysters grew 34% faster despite 39% less feeding time. Intense seasonal development of shell fouling by other suspension feeders like ascidians, mussels, and barnacles on subtidal (94% incidence) but not on aerially exposed intertidal (21-38% incidence) oysters may explain why duration of water cover failed to predict spring growth differences. Less intense fouling develops on intertidal oysters due to the physiological stress of aerial exposure on settlers, especially during higher temperatures and longer solar exposures of spring. Fouling by suspension feeders is known to reduce growth of the host through localized competition for food and added energetic costs. Thus, in springtime, indirect effects of aerial exposure providing a partial refuge from biological enemies overwhelmed direct effects of reduced duration of water coverage to reverse the expected pattern of slower intertidal

  15. Ultrastructure, molecular phylogenetics, and chlorophyll a content of novel cyanobacterial symbionts in temperate sponges.

    PubMed

    Erwin, Patrick M; López-Legentil, Susanna; Turon, Xavier

    2012-10-01

    Marine sponges often harbor photosynthetic symbionts that may enhance host metabolism and ecological success, yet little is known about the factors that structure the diversity, specificity, and nature of these relationships. Here, we characterized the cyanobacterial symbionts in two congeneric and sympatric host sponges that exhibit distinct habitat preferences correlated with irradiance: Ircinia fasciculata (higher irradiance) and Ircinia variabilis (lower irradiance). Symbiont composition was similar among hosts and dominated by the sponge-specific cyanobacterium Synechococcus spongiarum. Phylogenetic analyses of 16S-23S rRNA internal transcribed spacer (ITS) gene sequences revealed that Mediterranean Ircinia spp. host a specific, novel symbiont clade ("M") within the S. spongiarum species complex. A second, rare cyanobacterium related to the ascidian symbiont Synechocystis trididemni was observed in low abundance in I. fasciculata and likewise corresponded to a new symbiont clade. Symbiont communities in I. fasciculata exhibited nearly twice the chlorophyll a concentrations of I. variabilis. Further, S. spongiarum clade M symbionts in I. fasciculata exhibited dense intracellular aggregations of glycogen granules, a storage product of photosynthetic carbon assimilation rarely observed in I. variabilis symbionts. In both host sponges, S. spongiarum cells were observed interacting with host archeocytes, although the lower photosynthetic activity of Cyanobacteria in I. variabilis suggests less symbiont-derived nutritional benefit. The observed differences in clade M symbionts among sponge hosts suggest that ambient irradiance conditions dictate symbiont photosynthetic activity and consequently may mediate the nature of host-symbiont relationships. In addition, the plasticity exhibited by clade M symbionts may be an adaptive attribute that allows for flexibility in host-symbiont interactions across the seasonal fluctuations in light and temperature characteristic of

  16. Larval and metamorphic development of the foregut and proboscis in the caenogastropod Marsenina (Lamellaria) stearnsii.

    PubMed

    Page, L R

    2002-05-01

    The specialized, postmetamorphic feeding structures of predatory caenogastropods evolved by changes to an ancestral caenogastropod developmental program that generated a planktotrophic larval stage followed by a herbivorous postmetamorphic stage. As part of a program of comparative studies aimed at reconstructing these developmental changes, I studied the development of the postmetamorphic feeding system of Marsenina stearnsii using histological sections for light microscopy and scanning and transmission electron microscopy. The feeding system of this species has two very different designs during ontogeny. The larval system uses ciliary effectors to capture and ingest microalgae, whereas the juvenile/adult system includes a proboscis, jaws, and radular apparatus for predation on ascidian zooids. The postmetamorphic foregut begins to develop during the early larval phase, but the anlagen does not interfere with larval feeding because it develops as an increasingly elaborate outpocketing from the ventral wall of the larval esophagus. At metamorphosis, an opening is created in the anterior tip of the prospective, postmetamorphic buccal cavity and the margins of this opening anneal with the metamorphically remodeled lips of the larval mouth. This process exposes the jaws, which differentiate within the buccal cavity prior to metamorphosis. As a working hypothesis, I suggest that rupture of the buccal cavity to the outside at metamorphosis was selected as a mechanism to allow precocious development of jaws in species where jaws enhanced feeding performance by young juveniles. The larval esophagus of M. stearnsii appears to be completely destroyed at metamorphosis. Larval esophageal cells have distinctive apical characteristics (cilia, blebbed microvilli, stacks of lamellae within the glycocalyx) and no cells having this signature persist through metamorphosis. Development of the proboscis and proboscis sac, which begins prior to metamorphosis, conforms to previous

  17. Habitat-associations of turban snails on intertidal and subtidal rocky reefs.

    PubMed

    Smoothey, Amy F

    2013-01-01

    Patchiness of habitat has important influences on distributions and abundances of organisms. Given the increasing threat of loss and alteration of habitats due to pressures associated with humans, there is a need for ecologists to understand species' requirements for habitat and to predict changes to taxa under various future environmental conditions. This study tested hypotheses about the generality of patterns described for one species of marine intertidal turban snail for a different, yet closely-related species in subtidal habitats along the coast of New South Wales, Australia. These two closely-related species live in similar habitats, yet under quite different conditions, which provided an opportunity to investigate how similar types of habitats influence patterns of distribution, abundance and size-structure in intertidal versus subtidal environments. For each species, there were similar associations between biogenically structured habitat and densities. The intertidal species, Turbo undulates, were more abundant, with greater proportions of small individuals in habitats formed by the canopy-forming alga, Hormosira banksii, the solitary ascidian, Pyura stolonifera or the turfing red alga, Corallina officinalis compared to simple habitat (bare rock). Similarly, more Turbo torquatus were found in biogenically structured subtidal habitat, i.e. canopy-forming algae, Ecklonia radiata, mixed algal communities ('fringe'), or turfing red algae (Corallina officinalis and Amphiroa aniceps) than where habitat is simple (barrens). Small T. torquatus were more abundant in areas of turf and 'fringe', while large snails were more abundant in areas of kelp and barrens. These patterns were found at each location sampled (i.e. eight intertidal and two subtidal rocky reefs) and at all times of sampling, across each environment. This study highlighted the consistent influence of biogenically structured habitats on the distribution, abundance and size-structure of intertidal and

  18. An Expanded Notch-Delta Model Exhibiting Long-Range Patterning and Incorporating MicroRNA Regulation

    PubMed Central

    Chen, Jerry S.; Gumbayan, Abygail M.; Zeller, Robert W.; Mahaffy, Joseph M.

    2014-01-01

    Notch-Delta signaling is a fundamental cell-cell communication mechanism that governs the differentiation of many cell types. Most existing mathematical models of Notch-Delta signaling are based on a feedback loop between Notch and Delta leading to lateral inhibition of neighboring cells. These models result in a checkerboard spatial pattern whereby adjacent cells express opposing levels of Notch and Delta, leading to alternate cell fates. However, a growing body of biological evidence suggests that Notch-Delta signaling produces other patterns that are not checkerboard, and therefore a new model is needed. Here, we present an expanded Notch-Delta model that builds upon previous models, adding a local Notch activity gradient, which affects long-range patterning, and the activity of a regulatory microRNA. This model is motivated by our experiments in the ascidian Ciona intestinalis showing that the peripheral sensory neurons, whose specification is in part regulated by the coordinate activity of Notch-Delta signaling and the microRNA miR-124, exhibit a sparse spatial pattern whereby consecutive neurons may be spaced over a dozen cells apart. We perform rigorous stability and bifurcation analyses, and demonstrate that our model is able to accurately explain and reproduce the neuronal pattern in Ciona. Using Monte Carlo simulations of our model along with miR-124 transgene over-expression assays, we demonstrate that the activity of miR-124 can be incorporated into the Notch decay rate parameter of our model. Finally, we motivate the general applicability of our model to Notch-Delta signaling in other animals by providing evidence that microRNAs regulate Notch-Delta signaling in analogous cell types in other organisms, and by discussing evidence in other organisms of sparse spatial patterns in tissues where Notch-Delta signaling is active. PMID:24945987

  19. Homarine as a feeding deterrent in common shallow-water antarctic lamellarian gastropodMarseniopsis mollis: A rare example of chemical defense in a marine prosobranch.

    PubMed

    McClintock, J B; Baker, B J; Hamann, M T; Yoshida, W; Slattery, M; Heine, J N; Bryan, P J; Jayatilake, G S; Moon, B H

    1994-10-01

    The common bright yellow antarctic lamellarian gastropodMarseniopsis mollis was examined for the presence of defensive chemistry. Proton nuclear magnetic resonance (NMR) spectroscopy indicated that a major component of ethanolic extracts purified by reversed-phase column chromatography was homarine. Further high-performance liquid chromatography (HPLC) analysis of the mantle, foot, and viscera verified the presence of homarine in all body tissues at concentrations ranging from 6 to 24 mg/g dry tissue. A conspicuous macroinvertebrate predator of the shallow antarctic benthos, the sea starOdontaster validus, always rejected live individuals ofM. mollis, while readily feeding on pieces of fish tail muscle. Filter paper disks treated with shrimp elicited a broad range of feeding behaviors in the sea starO. validus (movement of disc to mouth, extrusion of cardiac stomach, humped feeding posture). Shrimp disks treated with homarine (0.4 and 4 mg/disk) were rejected byO. validus significantly more frequently than control disks treated with solvent carrier and shrimp or shrimp alone. The highest concentration of homarine tested not only caused feeding deterrence, but in several sea stars a flight response was noted. Homarine was not detected in the tunic of the antarctic ascidianCnemidocarpa verrucosa, a presumed primary prey ofM. mollis. Nonetheless, crude extracts of the epizooites that foul the tunic (primarily the bryozoans and hydroids) contain homarine, suggestingM. mollis may ingest and derive its chemistry from these organisms. This appears to be only the third example of chemical defense in a member of the Order Mesogastropoda. As the vestigial internalized shell ofM. mollis is considered a primitive condition, the findings of this study lend support to the hypothesis that chemical defense evolved prior to shell loss in shell-less gastropods. PMID:24241830

  20. Population genetics features for persistent, but transient, Botryllus schlosseri (Urochordata) congregations in a central Californian marina.

    PubMed

    Karahan, Arzu; Douek, Jacob; Paz, Guy; Rinkevich, Baruch

    2016-08-01

    The colonial tunicate Botryllus schlosseri is a globally distributed, invasive ascidian that has colonized the Californian coasts of the USA during the mid-late 1940s and has, since the late 1980s, spread north to Washington. This study analyzes the population genetic characteristics of transient populations residing at the Elkhorn Yacht-Club (EYC), in central California (seven sessions, 1996-2008), which suffered periodic catastrophes caused by episodic fresh-water floods and a single sampling session (in the year 2001) of five West-Coast populations using the mtDNA COI gene and five microsatellite markers. EYC microsatellite results were further compared with the closely situated but persistent population of the Santa Cruz Harbor (SCH) to understand the impact on EYC population regeneration processes after the 2005-flood catastrophe. All microsatellites were highly polymorphic, revealing a large number of unique alleles at different sampling dates. Whereas pairwise θ did not reveal significant differences between the EYC time-series samplings, the overall θ was significant, as it was between all the 2001 West Coast populations. The most likely cluster number was 3 for the EYC samples whereas two K values were obtained (2 and 5) for the 2001 samples. Tajima's D and Fu's/Fs tests did not reject the null hypothesis for COI neutral evolution, except for in the EYC-2000, 2007 and two 2001 samplings. The wide geographical range of the analyses has indicated that following the EYC 2005-flood catastrophe, newcomers could have originated from neighboring populations, from deep-water colonies that may have escaped the 2005 low salinity event, or less expectedly, from far away West-Coast populations, while revealing that the SCH population is the most probable source for the EYC population. PMID:27154209

  1. Tough Adults, Frail Babies: An Analysis of Stress Sensitivity across Early Life-History Stages of Widely Introduced Marine Invertebrates

    PubMed Central

    Pineda, M. Carmen; McQuaid, Christopher D.; Turon, Xavier; López-Legentil, Susanna; Ordóñez, Víctor; Rius, Marc

    2012-01-01

    All ontogenetic stages of a life cycle are exposed to environmental conditions so that population persistence depends on the performance of both adults and offspring. Most studies analysing the influence of abiotic conditions on species performance have focussed on adults, while studies covering early life-history stages remain rare. We investigated the responses of early stages of two widely introduced ascidians, Styela plicata and Microcosmus squamiger, to different abiotic conditions. Stressors mimicked conditions in the habitats where both species can be found in their distributional ranges and responses were related to the selection potential of their populations by analysing their genetic diversity. Four developmental stages (egg fertilisation, larval development, settlement, metamorphosis) were studied after exposure to high temperature (30°C), low salinities (26 and 22‰) and high copper concentrations (25, 50 and 100 µg/L). Although most stressors effectively led to failure of complete development (fertilisation through metamorphosis), fertilisation and larval development were the most sensitive stages. All the studied stressors affected the development of both species, though responses differed with stage and stressor. S. plicata was overall more resistant to copper, and some stages of M. squamiger to low salinities. No relationship was found between parental genetic composition and responses to stressors. We conclude that successful development can be prevented at several life-history stages, and therefore, it is essential to consider multiple stages when assessing species' abilities to tolerate stress. Moreover, we found that early development of these species cannot be completed under conditions prevailing where adults live. These populations must therefore recruit from elsewhere or reproduce during temporal windows of more benign conditions. Alternatively, novel strategies or behaviours that increase overall reproductive success might be

  2. The Substantial First Impact of Bottom Fishing on Rare Biodiversity Hotspots: A Dilemma for Evidence-Based Conservation

    PubMed Central

    Cook, Robert; Fariñas-Franco, Jose M.; Gell, Fiona R.; Holt, Rohan H. F.; Holt, Terry; Lindenbaum, Charles; Porter, Joanne S.; Seed, Ray; Skates, Lucie R.; Stringell, Thomas B.; Sanderson, William G.

    2013-01-01

    This study describes the impact of the first passage of two types of bottom-towed fishing gear on rare protected shellfish-reefs formed by the horse mussel Modiolus modiolus (L.). One of the study sites was trawled and the other was scallop-dredged. Divers collected HD video imagery of epifauna from quadrats at the two study sites and directed infaunal samples from one site. The total number of epifaunal organisms was significantly reduced following a single pass of a trawl (90%) or scallop dredge (59%), as was the diversity of the associated community and the total number of M. modiolus at the trawled site. At both sites declines in anthozoans, hydrozoans, bivalves, echinoderms and ascidians accounted for most of the change. A year later, no recovery was evident at the trawled site and significantly fewer infaunal taxa (polychaetes, malacostracans, bivalves and ophuroids) were recorded in the trawl track. The severity of the two types of impact reflected the undisturbed status of the habitats compared to previous studies. As a ‘priority habitat’ the nature of the impacts described on M. modiolus communities are important to the development of conservation management policy and indicators of condition in Marine Protected Areas (EU Habitats Directive) as well as indicators of ‘Good Environmental Status’ under the European Union Marine Strategy Framework Directive. Conservation managers are under pressure to support decisions with good quality evidence. Elsewhere, indirect studies have shown declines of M. modiolus biogenic communities in fishing grounds. However, given the protected status of the rare habitat, premeditated demonstration of direct impact is unethical or illegal in Marine Protected Areas. This study therefore provides a unique opportunity to investigate the impact from fishing gear whilst at the same time reflecting on the dilemma of evidence-based conservation management. PMID:23967063

  3. CiMutT, an asidian MutT homologue, has a 7, 8-dihydro-8-oxo-dGTP pyrophosphohydrolase activity responsible for sanitization of oxidized nucleotides in Ciona intestinalis.

    PubMed

    Yonekura, Shin-Ichiro; Sanada, U; Zhang-Akiyama, Qiu-Mei

    2010-01-01

    The oxidized nucleotide precursors 7, 8-dihydro-8-oxo-dGTP (8-oxo-dGTP) and 1, 2-dihydro-2-oxo-dATP (2-oxo-dATP) are readily incorporated into nascent DNA strands during replication, which would cause base substitution mutations. E. coli MutT and human homologue hMTH1 hydrolyze 8-oxo-dGTP, thereby preventing mutations. In this study, we searched for hMTH1 homologues in the ascidian Ciona intestinalis using the NCBI-BLAST database. Among several candidates, we focused on one open reading frame, designated as CiMutT, because of its high degree of identity (41.7%) and similarity (58.3%) to the overall amino acid sequence of hMTH1, including the Nudix box. CiMutT significantly suppressed the mutator activity of E. coli mutT mutant. Purified CiMutT had a pyrophosphohydrolase activity that hydrolyzed 8-oxo-dGTP to 8-oxo-dGMP and inorganic pyrophosphate. It had a pH optimum of 9.5 and Mg(++) requirement with optimal activity at 5 mM. The activity of CiMutT for 8-oxo-dGTP was comparable to that of hMTH1, while it was 100-fold lower for 2-oxo-dATP than that of hMTH1. These facts indicate that CiMutT is a functional homologue of E. coli MutT. In addition, the enzyme hydrolyzed all four of the unoxidized nucleoside triphosphates, with a preference for dATP. The specific activity for 8-oxo-dGTP was greater than that for unoxidized dATP and dGTP. These results suggest that CiMutT has the potential to prevent mutations by 8-oxo-dGTP in C. intestinalis. PMID:21178309

  4. Histamine Stimulates Ciliary Beat Frequency via the H2 Receptor in the Protochordate Botryllus schlosseri.

    PubMed

    Cima, Francesca; Franchi, Nicola

    2016-05-01

    Histamine is a biogenic molecule that plays a role in many physiological pathways via binding to a specific receptor. Histaminergic receptors belong to the large family of seven-transmembrane α-helix domain receptors classified in mammals into four distinct classes: H1, H2, H3, and H4. Despite being widely studied in vertebrates, few data are available on the invertebrate receptors, with only predicted H1 and H2 sequences for nonchordate deuterostomes. Here, we report the first characterized transcript sequence for an H2 receptor from the colonial ascidian Botryllus schlosseri, describing the localization of both transcript and protein during blastogenic development through in situ hybridization and immunohistochemistry. Its phylogenetic relationships with deuterostome orthologous proteins are reported, its role in ciliary beat frequency (CBF) in cultured stigma cells of the branchial basket is outlined, and the effects of histamine and its receptor agonists and antagonists are analyzed. In the presence of increasing concentrations of histamine in the medium, CBF increases similarly to the selective H2 receptor agonist dimaprit. In contrast, ranitidine, which is an inhibitor of the H2 receptor, causes a significant inhibition of CBF, similar to that observed after preincubation with the specific anti-BsHRH2 or the anti-human HRH2 antibody. In cells bordering the branchial basket stigmata, both antibodies colocalize in the proximal region of the ciliary plasmalemma, and histamine is present inside vesicles of the apical region, thus supporting the hypothesis of a histamine-binding H2 receptor control of the pharyngeal mucociliary transport similar to that of the upper respiratory tract and middle ear in mammals. PMID:27139577

  5. Biomixing generated by benthic filter feeders: a diffusion model for near-bottom phytoplankton depletion

    NASA Astrophysics Data System (ADS)

    Larsena, Poul S.; Riisgård, Hans Ulrik

    1997-05-01

    Transient concentration distributions of flagellate cells ( Rhodomonas sp.) previously measured by Riisgård and co-workers in laboratory experiments have been examined to develop a diffusion model for the process of phytoplankton depletion in stagnant seawater above populations of benthic filter feeders, the polychaete Nereis diversicolor and the ascidian Ciona intestinalis, respectively. The model is based on sinks located at inhalant openings and Fick's law with an effective diffusivity that decreases with distance above the bottom due to the biomixing generated by exhalant and inhalant feeding currents. For N. diversicolor, having inhalant and exhalant openings flush with the sediment surface and a moderate exhalant jet velocity of ˜0.01 m s -1, concentration boundary layer growth is retarded and limited by the low values of diffusivity prevailing at heights greater >˜0.05 m above the bottom. For C. intestinalis, having inhalant and exhalant openings situated ˜0.05-0.1 m above the bottom and a higher and inclined exhalant jet velocity of ˜0.1-0.2 m s -1, the concentration distributions show a nearly uniform depletion over a layer reaching a thickness of 0.2-0.3 m above the bottom due to high biomixing in this layer. Numerical predictions of concentration distributions reproduce essential features of experiments, and suggest near-bottom values of effective diffusivity of 0.3 x 10 -6 and 150 x 10 -6 m 2 s -1, for N. diversicolor and C. intestinalis, respectively. It is suggested that the latter value is so large that the induced mixing should be accounted for in modelling benthic concentration boundary layers under flow conditions.

  6. Sperm proteasomes degrade sperm receptor on the egg zona pellucida during mammalian fertilization.

    PubMed

    Zimmerman, Shawn W; Manandhar, Gaurishankar; Yi, Young-Joo; Gupta, Satish K; Sutovsky, Miriam; Odhiambo, John F; Powell, Michael D; Miller, David J; Sutovsky, Peter

    2011-01-01

    Despite decades of research, the mechanism by which the fertilizing spermatozoon penetrates the mammalian vitelline membrane, the zona pellucida (ZP) remains one of the unexplained fundamental events of human/mammalian development. Evidence has been accumulating in support of the 26S proteasome as a candidate for echinoderm, ascidian and mammalian egg coat lysin. Monitoring ZP protein degradation by sperm during fertilization is nearly impossible because those few spermatozoa that penetrate the ZP leave behind a virtually untraceable residue of degraded proteins. We have overcome this hurdle by designing an experimentally consistent in vitro system in which live boar spermatozoa are co-incubated with ZP-proteins (ZPP) solubilized from porcine oocytes. Using this assay, mimicking sperm-egg interactions, we demonstrate that the sperm-borne proteasomes can degrade the sperm receptor protein ZPC. Upon coincubation with motile spermatozoa, the solubilized ZPP, which appear to be ubiquitinated, adhered to sperm acrosomal caps and induced acrosomal exocytosis/formation of the acrosomal shroud. The degradation of the sperm receptor protein ZPC was assessed by Western blotting band-densitometry and proteomics. A nearly identical pattern of sperm receptor degradation, evident already within the first 5 min of coincubation, was observed when the spermatozoa were replaced with the isolated, enzymatically active, sperm-derived proteasomes. ZPC degradation was blocked by proteasomal inhibitors and accelerated by ubiquitin-aldehyde(UBAL), a modified ubiquitin protein that stimulates proteasomal proteolysis. Such a degradation pattern of ZPC is consistent with in vitro fertilization studies, in which proteasomal inhibitors completely blocked fertilization, and UBAL increased fertilization and polyspermy rates. Preincubation of intact zona-enclosed ova with isolated active sperm proteasomes caused digestion, abrasions and loosening of the exposed zonae, and significantly reduced

  7. Disentangling the impacts of heat wave magnitude, duration and timing on the structure and diversity of sessile marine assemblages

    PubMed Central

    Yunnie, Anna L.E.; Vance, Thomas; Widdicombe, Stephen

    2015-01-01

    Extreme climatic events, including heat waves (HWs) and severe storms, influence the structure of marine and terrestrial ecosystems. Despite growing consensus that anthropogenic climate change will increase the frequency, duration and magnitude of extreme events, current understanding of their impact on communities and ecosystems is limited. Here, we used sessile invertebrates on settlement panels as model assemblages to examine the influence of HW magnitude, duration and timing on marine biodiversity patterns. Settlement panels were deployed in a marina in southwest UK for ≥5 weeks, to allow sufficient time for colonisation and development of sessile fauna, before being subjected to simulated HWs in a mesocosm facility. Replicate panel assemblages were held at ambient sea temperature (∼17 °C), or +3 °C or +5 °C for a period of 1 or 2 weeks, before being returned to the marina for a recovery phase of 2–3 weeks. The 10-week experiment was repeated 3 times, staggered throughout summer, to examine the influence of HW timing on community impacts. Contrary to our expectations, the warming events had no clear, consistent impacts on the abundance of species or the structure of sessile assemblages. With the exception of 1 high-magnitude long-duration HW event, warming did not alter not assemblage structure, favour non-native species, nor lead to changes in richness, abundance or biomass of sessile faunal assemblages. The observed lack of effect may have been caused by a combination of (1) the use of relatively low magnitude, realistic heat wave treatments compared to previous studies (2), the greater resilience of mature adult sessile fauna compared to recruits and juveniles, and (3) the high thermal tolerance of the model organisms (i.e., temperate fouling species, principally bryozoans and ascidians). Our study demonstrates the importance of using realistic treatments when manipulating climate change variables, and also suggests that biogeographical context may

  8. Molecular cloning and bioinformatic analysis of SPATA4 gene.

    PubMed

    Liu, Shang-feng; Ai, Chao; Ge, Zhong-qi; Liu, Hai-luo; Liu, Bo-wen; He, Shan; Wang, Zhao

    2005-11-30

    Full-length cDNA sequences of four novel SPATA4 genes in chimpanzee, cow, chicken and ascidian were identified by bioinformatic analysis using mouse or human SPATA4 cDNA fragment as electronic probe. All these genes have 6 exons and have similar protein molecular weight and do not localize in sex chromosome. The mouse SPATA4 sequence is identified as significantly changed in cryptorchidism, which shares no significant homology with any known protein in swissprot databases except for the homologous genes in various vertebrates. Our searching results showed that all SPATA4 proteins have a putative conserved domain DUF1042. The percentages of putative SPATA4 protein sequence identity ranging from 30 % to 99 %. The high similarity was also found in 1 kb promoter regions of human, mouse and rat SPATA4 gene. The similarities of the sequences upstream of SPATA4 promoter also have a high proportion. The results of searching SymAtlas (http://symatlas.gnf.org/SymAtlas/) showed that human SPATA4 has a high expression in testis, especially in testis interstitial, leydig cell, seminiferous tubule and germ cell. Mouse SPATA4 was observed exclusively in adult mouse testis and almost no signal was detected in other tissues. The pI values of the protein are negative, ranging from 9.44 to 10.15. The subcellular location of the protein is usually in the nucleus. And the signal peptide possibilities for SPATA4 are always zero. Using the SNPs data in NCBI, we found 33 SNPs in human SPATA4 gene genomic DNA region, with the distribution of 29 SNPs in the introns. CpG island searching gives the data about CpG island, which shows that the regions of the CpG island have a high similarity with each other, though the length of the CpG island is different from each other. This research is a fundamental work in the fields of the bioinformational analysis, and also put forward a new way for the bioinformatic analysis of other genes. PMID:16336790

  9. The role of containerships as transfer mechanisms of marine biofouling species.

    PubMed

    Davidson, Ian C; Brown, Christopher W; Sytsma, Mark D; Ruiz, Gregory M

    2009-10-01

    Fouling of ships is an important historical and enduring transfer mechanism of marine nonindigenous species (NIS). Although containerships have risen to the forefront of global maritime shipping since the 1950s, few studies have directly sampled fouling communities on their submerged surfaces, and little is known about differences in the fouling characteristics among commercial ship types. Twenty-two in-service containerships at the Port of Oakland (San Francisco Bay, California) were sampled to test the hypothesis that the extent and taxonomic richness of fouling would be low on this type of ship, resulting from relatively fast speeds and short port durations. The data showed that the extent of macroorganisms (invertebrates and algae) was indeed low, especially across the large surface areas of the hull. Less than 1% of the exposed hull was colonized for all apart from one vessel. These ships had submerged surface areas of >7000 m(2), and fouling coverage on this area was estimated to be <17 m(2) per vessel, with zero biota detected on the hulls of many vessels. The outlying smaller vessel (4465 m(2)) had an estimated coverage of 90% on the hull and also differed substantially from the other ships in terms of its recent voyage history, shorter voyage range and slower speeds. Despite the low extent of fouling, taxonomic richness was high among vessels. Consistent with recent studies, a wide range of organisms were concentrated at more protected and heterogeneous (non-hull) niche areas, including rudders, stern tubes and intake gratings. Green algae and barnacles were most frequently sampled among vessels, but hydroids, bryozoans, bivalves and ascidians were also recorded. One vessel had 20 different species in its fouling assemblage, including non-native species (already established in San Francisco Bay) and mobile species that were not detected in visual surveys. In contrast to other studies, dry dock block areas did not support many organisms, despite little

  10. Effects of regular and irregular temporal patterns of disturbance on biomass accrual and species composition of a subtidal hard-bottom assemblage

    NASA Astrophysics Data System (ADS)

    Wollgast, Susanne; Lenz, Mark; Wahl, Martin; Molis, Markus

    2008-12-01

    Assessing patterns of species distribution and abundance is important to understand the driving processes of, and predict future changes in, biodiversity. To this date, ecological studies have been mainly designed to investigate the effects of the mean magnitude of predictor variables, although ecological factors naturally vary in space and time. In a nine month long field experiment, we tested the effects of different temporal patterns (regular, lowly and highly irregular) in biomass removal (=disturbance event) on the diversity, species composition, and biomass accrual of macrobenthic assemblages grown on 15 × 15 cm2 PVC-panels. For each pattern of disturbance, disturbance events were timed at three sequences to control for possible confounding effects with recruitment patterns. Disturbance intensity was kept identical among treatments. Assemblages developed in the absence of disturbance for 3 months prior to a 150-day manipulation period, during which the biomass from 20% of the panel area was removed at each of ten disturbance events. Additional undisturbed settlement panels were deployed in the field to assess monthly recruitment rates and species succession over a one year period. Disturbance (i) reduced biomass and total species cover, (ii) changed species composition during the first half of the manipulation period significantly, and (iii) was without effect on species richness and evenness. Irregular disturbance regimes enhanced the abundance of the ascidian Ciona intestinalis, biomass accrual, and total species cover of assemblages relative to the regular disturbance regime, but had either no or only transient effects on diversity and species composition, respectively. Neither the degree of irregularity in disturbance nor the sequence of disturbance events affected any of the response variables significantly. Recruitment of species was strongly seasonal with almost only diatoms recruiting during winter, while recruitment was most intense during summer

  11. Highlights of marine invertebrate-derived biosynthetic products: Their biomedical potential and possible production by microbial associants

    PubMed Central

    Radjasa, Ocky K.; Vaske, Yvette M.; Navarro, Gabriel; Vervoort, Hélène C.; Tenney, Karen; Linington, Roger G.; Crews, Phillip

    2011-01-01

    Coral reefs are among the most productive marine ecosystems and are the source of a large group of structurally unique biosynthetic products. Annual reviews of marine natural products continue to illustrate that the most prolific source of bioactive compounds consist of coral reef invertebrates—sponges, ascidians, mollusks, and bryozoans. This account examines recent milestone developments pertaining to compounds from invertebrates designated as therapeutic leads for biomedical discovery. The focus is on the secondary metabolites, their inspirational structural scaffolds and the possible role of microorganism associants in their biosynthesis. Also important are the increasing concerns regarding the collection of reef invertebrates for the discovery process. The case examples considered here will be useful to insure that future research to unearth bioactive invertebrate-derived compounds will be carried out in a sustainable and environmentally conscious fashion. Our account begins with some observations pertaining to the natural history of these organisms. Many still believe that a serious obstacle to the ultimate development of a marine natural product isolated from coral reef invertebrates is the problem of compound supply. Recent achievements through total synthesis can now be drawn on to forcefully cast this myth aside. The tools of semisynthesis of complex natural products or insights from SAR efforts to simplify an active pharmacophore are at hand and demand discussion. Equally exciting is the prospect that invertebrate-associated micro-organisms may represent the next frontier to accelerate the development of high priority therapeutic candidates. Currently in the United States there are two FDA approved marine-derived therapeutic drugs and two others that are often cited as being marine-inspired. This record will be examined first followed by an analysis of a dozen of our favorite examples of coral reef invertebrate natural products having therapeutic

  12. Hemichordates and the Origin of Chordates

    NASA Technical Reports Server (NTRS)

    Gerhart, John; Kirschner, Marc; Lowe, Chris

    2002-01-01

    At the start of the period of the NASA grant three years ago, we had no information on the organization and development of the body axis of the hemichordate, Saccoglossus kowalevskii. Now we have substantial findings about the anteroposterior axis and dorsoventral axis, and based on this information, we have new insights about the origin of chordates from ancestral deuterostomes. We found ways to obtain and preserve large numbers of embryos and hatched juveniles. We can now collect about 40,000 embryos in the month of September, the time of S. kowalevskii spawning at Woods Hole. Excellent cDNA libraries were prepared from three developmental stages. From these libraries, we directly isolated about 30 gene ortholog sequences by screening and pcr techniques, all of these sequences of interest in the inquiry about the animal's organization and development. We also performed a mid-sized EST project (60,000 randomly picked clones, many of these arrayed). About half of these have been analyzed so far by blastx and are suitable for direct use of clones. We have obtained about 50 interesting sequences from this set. The rest still await analysis. Thus, at this time we have isolated orthologs of 80 genes that are known to be expressed in chordates in conserved domains and known to have interesting roles in chordate organization and development. The orthology of the S. kowalevskii sequences has been verified by neighbor joining and parsimony methods, with bootstrap estimates of validity. The S. kowalevskii sequences cluster with other deuterostome sequences, namely, other hemichordates, echinoderms, ascidians, amphioxus, or vertebrates, depending on what sequences are available in the database for comparison. We have used these sequences to do high quality in situ hybridization on S. kowalevskii embryos, and the results can be divided into three sections-those concerning the anteroposterior axis of S. kowalevskii in comparison to the same axis of chordates, those concerning

  13. Complete mitochondrial genome sequences of two parasitic/commensal nemerteans, Gononemertes parasita and Nemertopsis tetraclitophila (Nemertea: Hoplonemertea)

    PubMed Central

    2014-01-01

    Background Most nemerteans (phylum Nemertea) are free-living, but about 50 species are known to be firmly associated with other marine invertebrates. For example, Gononemertes parasita is associated with ascidians, and Nemertopsis tetraclitophila with barnacles. There are 12 complete or near-complete mitochondrial genome (mitogenome) sequences of nemerteans available in GenBank, but no mitogenomes of none free-living nemerteans have been determined so far. In the present paper complete mitogenomes of the above two parasitic/commensal nemerteans are reported. Methods The complete mitochondrial genomes (mitogenome) of G. parasita and N. tetraclitophila were amplified by conventional and long PCR. Phylogenetic analyses of maximum likelihood (ML) and Bayesian inference (BI) were performed with both concatenated nucleotide and amino acid sequences. Results Complete mitogenomes of G. parasita and N. tetraclitophila are 14742 bp and 14597 bp in size, respectively, which are within the range of published Hoplonemertea mitogenomes. Their gene orders are identical to that of published Hoplonemertea mitogenomes, but different from those of Palaeo- and Heteronemertea species. All the coding genes, as well as major non-coding regions (mNCRs), are AT rich, which is especially pronounced at the third codon position. The AT/GC skew pattern of the coding strand is the same among nemertean mitogenomes, but is variable in the mNCRs. Some slight differences are found between mitogenomes of the present species and other hoplonemerteans: in G. parasita the mNCR is biased toward T and C (contrary to other hoplonemerteans) and the rrnS gene has a unique 58-bp insertion at the 5′ end; in N. tetraclitophila the nad3 gene starts with the ATT codon (ATG in other hoplonemerteans). Phylogenetic analyses of the nucleotide and amino acid datasets show early divergent positions of G. parasita and N. tetraclitophila within the analyzed Distromatonemertea species, and provide strong support for

  14. Speculation on the evolution of stem cells.

    PubMed

    Shostak, Stanley

    2008-01-01

    Profoundly different patterns of potency and division are exhibited by mammalian embryonic and adult stem cells. Additional confusion surrounds stem-cell surrogates, cache and reserve cells having some characteristics of stem cells and not others. Mystification may have been introduced historically with the concepts of determinate and regulative development, but, hopefully, the muddle can be resolved by tracing the evolution of stem cells in Metazoa. Blastomeres in marine sponges, cnidarians, lophotrochozoans, small ecdysozoans (e.g., Caenorhabditis elegans), and some deuterostomes (e.g., echinoderms and ascidians) exhibit determinative development. Their larval and adult cells have narrow potencies, sometimes coupled to virtually unlimited proliferation, and function in the growth, maintenance and regulation of body size. The embryos of larger arthropods and deuterostomes with well-provisioned eggs or viviparity, on the other hand, exhibit regulative development, while their larval "set-aside" or adult stem cells function in the growth, maintenance, and regulation of organ size coupled to constrained proliferation and cell turnover. Mammalian embryonic stem cells would seem adapted to rapid proliferation, functioning in part to enclose yolk or to acquire access to maternal resources. The cellular products of embryonic stem cells routinely come under global influences and give rise to the cells of germ layers and organ rudiments. Mammalian adult stem cells resemble the blastomeres of planktonic and benthic organisms with small eggs and may have evolved in mature organisms as an adaptation to the growth and maintenance of tissues via proliferation and the regulation of organ size via cell loss (e.g., terminal differentiation). Cancer stem cells, instrumental in metastasis, would seem to ignore mechanisms normally functioning in the removal of excess cells. Strategies for regenerative therapies in adult mammals, therefore, might be based on stimulating growth of

  15. Carbonate production and deposition in a warm-temperate macroalgal environment, Investigator Strait, South Australia

    NASA Astrophysics Data System (ADS)

    James, Noel P.; Bone, Yvonne

    2011-08-01

    The prolific macroalgal forests in shallow (< 20 m), warm-temperate, marine environments off southern Yorke Peninsula, South Australia have two carbonate-producing habitats, 1) upward-facing, exposed rock surfaces beneath large phaeophytes, and 2) concealed rock surfaces under overhangs, on rock walls, in crevasses, and indentations that all lie behind a curtain of brown macroalgae. Exposed surfaces have three growth tiers; 1) a basal, cm-high veneer or turf of crustose corallines, geniculate corallines, and short fleshy red algae that are grazed by herbivorous gastropods, 2) an intermediate, 5-20 cm-high community of fleshy red algae, and 3) a 20-100 cm+-high canopy of large phaeophytes (especially Ecklonia, Cystophora and Xiophora) whose blades are locally encrusted with bryozoans, such as Membranipora membranacea, and spirorbids. Concealed surfaces of subvertical rock walls and cryptic habitats behind the macroalgal curtain have two tiers; 1) a cornucopia of encrusting plants and animals, especially crustose and geniculate corallines in shallow water, that give way in water depths > 4 m to numerous bryozoans (especially fenestrates), serpulid worms, numerous and diverse demosponges, ascidians, small solitary corals, epifaunal echinoids, and gastropods, and 2) a veil of macroalgae (mainly Cystophora and Ecklonia) that drapes down and shades the rock walls. Most carbonate sediment production does not come from calcareous epiphytes on the macroalgae but comes from the coralline algae and calcareous invertebrates living on the rock walls and in concealed depressions. Mollusks (gastropods and bivalves) and geniculate coralline algae with numerous lithoclasts, crustose coralline fragments, barnacle plates, serpulid worms, bryozoans, and large benthic foraminifers (especially Amphistegina) dominate the resultant gravels and sands; but there is little or no mud. This is because carbonate sediment is the result of production not only in the macrophyte factory but also in

  16. Impacts of trawling on benthic macro-fauna and -flora of the Spencer Gulf prawn fishing grounds

    NASA Astrophysics Data System (ADS)

    Svane, Ib; Hammett, Zoe; Lauer, Peter

    2009-05-01

    The overall effects of trawling on benthic habitats and their assemblages are dependent on the distribution and intensity of trawl effort. The benthic habitats of the Spencer Gulf prawn trawling grounds are subjected to known variable levels of trawling disturbance recorded from fisher's logbooks. These habitats have not been quantitatively investigated. The aim of the study was firstly to characterise the macro-faunal and -floral assemblages and secondly, to comparatively assess trawl impact by testing the null hypothesis of no differences between five sites exposed to different intensity of trawl effort. The distribution and abundance of benthic macro-fauna and -flora were studied at two sampling resolutions by using beam trawl sampling (˜10,000 m 2) and underwater stereophotography (˜4.5 m 2) at five sites with different levels of trawl disturbance (effort). The results showed that the Spencer Gulf prawn trawling grounds are characterised by sandy sediments with a low content of silt and clay, with the exception of one site with very fine gravel. Biomass, abundance and cover of macro-fauna and -flora were generally low throughout, but with large differences among sites. Biomass, abundance and cover were found to be negatively correlated to both trawl hours from 1994-1998 and during the period of study. ANOSIM and SIMPER analyses using biomass, abundance and percentage cover as variables showed significant differences between sites with eight species or taxonomic groups contributing more than 10% to the observed similarity within sites. The two northern sites were dominated by sponges and the bearded mussel, Trichomya hirsutus, and the southern hammer oyster, Malleus meridianus. Other species that contributed to the similarity within sites were the ascidian, Polycarpa viridis, mobile epifauna (the blue swimmer crab, Portunus pelagicus, and the western king prawn, Penaeus (Melicertus) latisulcatus) and demersal fish species (Degens leatherjacket, Thamnaconus

  17. Marine anoxia: quantifying short- and longer-term responses in situ

    NASA Astrophysics Data System (ADS)

    Pados, Theodora; Pretterebner, Katrin; Schiemer, Lucie; Riedel, Bettina; Stachowitsch, Michael; Zuschin, Martin

    2010-05-01

    , the moribund/dead organisms attracted predators/scavengers, which removed most of the dead material within days. Fish (Gobius niger; Diplodus vulgaris, Serranus hepatus) were the first post-anoxia visitors (after 9 min); their numbers gradually decreased during the deployment, suggesting that most of the suitable dead material was consumed early. The second and third groups arriving were hermit crabs and gastropods, respectively. They fed mainly on remains not utilized by fishes (e.g. sponges, ascidians). The results provide an opportunity to better interpret benthic responses to anoxic events in Earth's history.

  18. Differential Responses of Emergent Intertidal Coral Reef Fauna to a Large-Scale El-Niño Southern Oscillation Event: Sponge and Coral Resilience

    PubMed Central

    Kelmo, Francisco; Bell, James J.; Moraes, Simone Souza; Gomes, Rilza da Costa Tourinho; Mariano-Neto, Eduardo; Attrill, Martin J.

    2014-01-01

    There is a paucity of information on the impacts of the 1997–8 El Niño event and subsequent climatic episodes on emergent intertidal coral reef assemblages. Given the environmental variability intertidal reefs experience, such reefs may potentially be more resilient to climatic events and provide important insights into the adaptation of reef fauna to future ocean warming. Here we report the results of a 17-year (1995–2011) biodiversity survey of four emergent coral reef ecosystems in Bahia, Brazil, to assess the impact of a major El Niño event on the reef fauna, and determine any subsequent recovery. The densities of two species of coral, Favia gravida and Siderastrea stellata, did not vary significantly across the survey period, indicating a high degree of tolerance to the El Niño associated stress. However, there were marked decreases in the diversity of other taxa. Molluscs, bryozoans and ascidians suffered severe declines in diversity and abundance and had not recovered to pre-El Niño levels by the end of the study. Echinoderms were reduced to a single species in 1999, Echinometra lucunter, although diversity levels had recovered by 2002. Sponge assemblages were not impacted by the 1997–8 event and their densities had increased by the study end. Multivariate analysis indicated that a stable invertebrate community had re-established on the reefs after the El Niño event, but it has a different overall composition to the pre-El Niño community. It is unclear if community recovery will continue given more time, but our study highlights that any increase in the frequency of large-scale climatic events to more than one a decade is likely to result in a persistent lower-diversity state. Our results also suggest some coral and sponge species are particularly resilient to the El Niño-associated stress and therefore represent suitable models to investigate temperature adaptation in reef organisms. PMID:24675785

  19. Total Synthesis, Stereochemical Revision, and Biological Reassessment of Mandelalide A: Chemical Mimicry of Intrafamily Relationships.

    PubMed

    Willwacher, Jens; Heggen, Berit; Wirtz, Conny; Thiel, Walter; Fürstner, Alois

    2015-07-13

    Mandelalide A and three congeners had recently been isolated as the supposedly highly cytotoxic principles of an ascidian collected off the South African coastline. Since these compounds are hardly available from the natural source, a concise synthesis route was developed, targeting structure 1 as the purported representation of mandelalide A. The sequence involves an iridium-catalyzed two-directional Krische allylation and a cobalt-catalyzed carbonylative epoxide opening as entry points for the preparation of the major building blocks. The final stages feature the first implementation of terminal acetylene metathesis into natural product total synthesis, which is remarkable in that this class of substrates had been beyond the reach of alkyne metathesis for decades. Synthetic 1, however, proved not to be identical with the natural product. In an attempt to clarify this issue, NMR spectra were simulated for 20 conceivable diastereomers by using DFT followed by DP4 analysis; however, this did not provide a reliable assignment either. The puzzle was ultimately solved by the preparation of three diastereomers, of which compound 6 proved identical with mandelalide A in all analytical and spectroscopic regards. As the entire "northern sector" about the tetrahydrofuran ring in 6 shows the opposite configuration of what had originally been assigned, it is highly likely that the stereostructures of the sister compounds mandelalides B-D must be corrected analogously; we propose that these natural products are accurately represented by structures 68-70. In an attempt to prove this reassignment, an entry into mandelalides C and D was sought by subjecting an advanced intermediate of the synthesis of 6 to a largely unprecedented intramolecular Morita-Baylis-Hillman reaction, which furnished the γ-lactone derivative 74 as a mixture of diastereomers. Whereas (24R)-74 was amenable to a hydroxyl-directed dihydroxylation by using OsO4 /TMEDA as the reagent, the sister

  20. Causes and consequences of hypoxia on the Western Black Sea Shelf

    NASA Astrophysics Data System (ADS)

    Friedrich, Jana; Gomoiu, Marian-Trajan; Naeher, Sebastian; Secrieru, Dan; Teaca, Adrian

    2013-04-01

    opportunistic species such as worms. Following the economic collapse of eastern European countries during the 1990s, riverine nutrient loads decreased and the ecosystem is showing signs of slow recovery, such as a decrease in the frequency and duration of hypoxic events. However, nutrient fluxes from the sediments did not decrease significantly (Friedrich et al. 2010). We observe slight recovery of the macrobenthic community structure in terms of species numbers in the Romanian pre-Danubian sector. Opportunistic species, e.g., ascidians, worms and fast growing filamentous algae are currently filling ecologic niches left by the past ecosystem collapse. References Friedrich, J., Cociasu, A., & Mee, L. D. (2010). Historical legacy of Danube River nutrient discharge and eutrophication in the North-Western Black Sea - Nutrient recycling in the shelf sediments. Danube News, 12(22), 7-9. Friedrich J., Dinkel C., Friedl G., Pimenov N., Wijsman J., Gomoiu M.T., Cociasu A., Popa L. & Wehrli B. (2002). Benthic Nutrient Cycling and Diagenetic Pathways in the North-western Black Sea. Estuarine, Coastal and Shelf Science, 54, 369-383. Jones G.A. & Gagnon A.R. (1994). Radiocarbon chronology of Black Sea sediments. Deep Sea Research Part I: Oceanographic Research Papers, 41, 531-557. Mee L.D., Friedrich J. & Gomoiu M.-T. (2005). Restoring the Black Sea in times of uncertainty. Oceanography, 18, 32-43. Oguz, T. and Gilbert, D. (2007). Abrupt transitions of the top-down controlled Black Sea pelagic ecosystem during 1960-2000: Evidence for regime-shifts under strong fishery exploitation and nutrient enrichment modulated by climate-induced variations. Deep-Sea Research I: doi:10.1016/j.dsr.200609.200010.

  1. Influence of solar activity on the development of calcareous nannofossils from a Middle Holocene costal paleo-ria (SW Portugal)

    NASA Astrophysics Data System (ADS)

    Hernández, Armand; Cachão, Mário; Trigo, Ricardo M.; Conceição Freitas, M.

    2015-04-01

    A 27 m long core was recovered from a present day flat-floored small fluvial valley, tributary of the Mira River (SW Portugal) allowing to span almost the complete Holocene sedimentary sequence directly overlaying Paleozoic schists and greywackes. A high resolution study of its micropaleontological content (Alday et al. 2006) was performed and 5 sedimentary stages were established: i) a coccolith-barren lower fluvial stage; ii) a coccolith intermittent lower estuarine stage; iii) a coccolith rich marine (ria) stage; iv) a coccolith intermittent upper estuarine/lagoonal stage and v) a coccolith-barren upper fluvial stage. The usefulness of calcareous nannofossils as natural tracers of the marine sedimentation contributing with valuable information for environmental reconstructions has been thoroughly demonstrated. Here, we present a high-resolution paleoenvironmental reconstruction from the interpreted marine (ria) section of the core, between 8.8k and 4.8k cal yr BP using most abundant calcareous nannofossils. Factor Analysis retrieved two major factors from the coccolith assemblages. Factor 1 (24% var.) is related to oceanic affinity community (e.g. Gephyrocapsa muellerae, Syracosphaera pulchra and Umbilicosphaera sibogae) whereas Factor 2 (23% var.) is linked to coastal neritic taxa (e.g. Ascidian spicules, Gephyrocapsa oceanica, Coccolithus pelagicus braarudii, Heliscosphaera carteri and Braarudosphaera bigelowii). These scores showed the existence of two episodes (8.8k to 7.4k and 5.8k to 5.2k cal yr BP) of marine colonization inside the paleoecological succession of the Holocene paleo-ria (8.8k and 4.8k cal yr BP). In order to establish the relationship between the solar activity and calcareous nannofossils sedimentation, cyclicity on the studied time series was investigated by performing spectral analysis on Factor 1 (F1) and Factor 2 (F2) scores. F1 score periodogram discloses three significant periodicities (460, 350 and 236-yrs) whereas F2 score