CONTRIBUTIONS TO THE JAPANESE ASCIDIAN FAUNA XXX. -FURTHER NOTES ON JAPANESE CLAVELINIDS-

Three more materials of Japanese clavelinids came into our hand after the Japanese clavelinids known so far had been reviewed (Nishikawa and Tokioka, 1976), two colonies collected from Sagami Bay and preserved at the Biological Laboratory of the Imperial Household, a single colony collected by Mr. Y. Yanagisawa from the Bonin Islands and a single colony collected by Prof. T. Kikuchi from the Ariake Sea, Kyusyu Island. The first included two species, Clavelina elegans (Oka) and a new species, the last was identified with C. elegans, while the second seemed to belong to C. molluccensis (Sluiter) that had not yet been recorded from the Japanese waters. As the range of morphological variations in C. elegans is known but still very insufficiently, it is considered significant to record some features of these two more colonies again in the present paper. In addition to this, a brief description is given as to C. molluccensis to confirm the identification and a full description is made on the new species of Clavelina, to which the name of viola is proposed by us for its characteristic colouration when alive. Before going further, we wish to express our gratitude for the privilege of examining the specimens of the Biological Laboratory of the Imperial Household and also our hearty thanks to Prof. T. Kikuchi of the Amakusa Marine Biological Laboratory of Kyusyu University and to Mr. Y. Yanagisawa, a graduate student at our laboratory, for their generosity in offering those interesting specimens to our examination

Phylogenetic position of a whale-fall lancelet (Cephalochordata) inferred from whole mitochondrial genome sequences

<p>Abstract</p> <p>Background</p> <p>The lancelet <it>Asymmetron inferum </it>(subphylum Cephalochordata) was recently discovered on the ocean floor off the southwest coast of Japan at a depth of 229 m, in an anaerobic and sulfide-rich environment caused by decomposing bodies of the sperm whale <it>Physeter macrocephalus</it>. This deep sulfide-rich habitat of <it>A. inferum </it>is unique among the lancelets. The distinguishing adaptation of this species to such an extraordinary habitat can be considered in a phylogenetic framework. As the first step of reconstruction of the evolutionary processes in this species, we investigated its phylogenetic position based on 11 whole mitochondrial genome sequences including the newly determined ones of the whale-fall lancelet <it>A. inferum </it>and two coral-reef congeners.</p> <p>Results</p> <p>Our phylogenetic analyses showed that extant lancelets are clustered into two major clades, the <it>Asymmetron </it>clade and the <it>Epigonichthys </it>+ <it>Branchiostoma </it>clade. <it>A. inferum </it>was in the former and placed in the sister group to <it>A. lucayanum </it>complex. The divergence time between <it>A. inferum </it>and <it>A. lucayanum </it>complex was estimated to be 115 Mya using the penalized likelihood (PL) method or 97 Mya using the nonparametric rate smoothing (NPRS) method (the middle Cretaceous). These are far older than the first appearance of large whales (the middle Eocene, 40 Mya). We also discovered that <it>A. inferum </it>mitogenome (mitochondrial genome) has been subjected to large-scale gene rearrangements, one feature of rearrangements being unique among the lancelets and two features shared with <it>A. lucayanum </it>complex.</p> <p>Conclusion</p> <p>Our study supports the monophyly of genus <it>Asymmetron </it>assumed on the basis of the morphological characters. Furthermore, the features of the <it>A. inferum </it>mitogenome expand our knowledge of variation within cephalochordate mitogenomes, adding a new case of transposition and inversion of the <it>trnQ </it>gene. Our divergence time estimation suggests that <it>A. inferum </it>remained a member of the Mesozoic and the early Cenozoic large vertebrate-fall communities before shifting to become a whale-fall specialist.</p

Genomic Approaches Reveal Unexpected Genetic Divergence Within Ciona intestinalis

Abstract. The invertebrate chordate Ciona intestinalis is a widely used model organism in biological research. Individuals from waters ranging from arctic to temperate are morphologically almost indistinguishable. However, we found significant differences in whole genomic DNA sequence between northern European and Pacific C. intestinalis. Intronic and transposon sequences often appear unrelated between these geographic origins and amino acid substitutions in protein coding sequences indicate a divergence time in excess of 20 MYA. This finding suggests the existence of two cryptic species within the present C. intestinalis species. We found five marker loci which distinguish the two genetic forms by PCR. This analysis revealed that specimens from Naples, Italy, have the Pacific-type genome, perhaps due to humanmediated marine transport of species. Despite major genomic divergence, the two forms could be hybridized in the laboratory

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

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

Diel patterns of zooplankton community structure in nearshore waters of different substrates off Tinggi and Sibu Islands, Malaysia, with special reference to copepods

The relationship between zooplankton community structure and selected environmental conditions was investigated by simultaneous two-day consecutive sampling in the waters overlying coral and sand sites off Sibu Island and a seagrass site off Tinggi Island, Johor, Malaysia. A total of 129 taxa were identified, 60 non-copepod taxa and 69 copepod species in all samples. Uni- and multi-variate analyses reveal distinct coral, sand, seagrass copepod assemblages with indicator copepod species and attributes of their size fractions. Small fraction (100–335 μm) samples contained greatest number of individuals, few rare species and were densest at onshore depths, and the opposite for large fraction (>335 μm) samples but were densest at nighttime and most species rich in the coral site at night. Higher species diversity at offshore stations is due likely to ecotonal effects of overlapping oceanic and nearshore communities. This study demonstrates the usefulness of uni- and multi-variate analyses in identifying patterns in zooplankton community structure in representative shallow tropical habitats, and the need for accurate zooplankton taxonomy, nighttime and daytime and onshore and offshore sampling, and size fractionation of samples

B. 「海洋生物の医薬資源開発-医薬を指向した海洋生物の有用物質の探索」

海洋生物はその種100万といわれ、地上における今もなお未知な世界である。本年度も、この海洋生物から、医薬資源となりうる有用な生理活性物質を発見し、構造を明らかにし、生物活性を検討することを目的として研究を行い、この研究を始めてから9年になった。本年採集した生物は、27種であり、今までに281件を採取している。採集生物リストをTableに示した。バイオアッセイを指標に、今まで、海草、アカフジツボ、クダウミヒドラ、スポンジ、エボヤ、ユーレイボヤ、イソギンチャク、群体ボヤ、オオワレカラ、コケムシ類等につき有用成分の探索を行った。特に、付着生物コケムシ(Bryzoa)類の各種の成分に注目し、各地で採集したフサコケムシBugula neritina、ホソフサコケムシTricellaria occidentalisおよびアメリカのフロリダ産フサコケムシAmathia convolutaの活性成分を検討し、有益な知見と新しい化学物質を単離・構造決定した。すなわち、昨年度報告したconvolutamine AとF以外にconvolutamine Gを、さらにlutamide C以外に、lutamide AとBおよびconvolutamydine Eの単離を行い、構造決定した。さらに、昨年から始めたこれらの有用な天然物の全合成研究に成果が見られ、3種のconvolutamine類A、CとFおよび2種のlutamide類AとCの合計5種の天然物の全合成を完成させた。この成果には、さらにanalogsの全合成を含み、化合物の構造とその活性との相関に研究が発展している。これらの結果は1999年度の日本化学会第75回春季年会で口頭発表され、さらに一部、チェコ化学会誌に掲載されている。これらの成果は、研究成果の概要に報告する。さらにまた、去年度の第75回日本化学会春季年会には、従来発表していなかった成果を再検討し、計5題の研究発表(ポスター)を行った(研究成果の概要を参照)

<所内学術研究成果報告>Q. 「海洋生物の医薬資源開-医薬を指向した海洋生物の探索と調査・開発」

約100万種といわれる海洋生物は,地上における最も未知の世界である。この海洋生物から,医薬資源となりうる有用な生理活性物質を発見し,構造を明らかにし,生理活性を検討することを目的としている。NIHで臨床試験中のドラスタチン10(ウミウシ成分)とブリオスタチン1(フサコケムシ成分)は,釡野がその研究に携わったものである。平成元年以来,日野,西川等の協力を得て,平塚付近(相模湾)および岩手県大槌町付近(大槌湾)の海洋生物を検討し,特に青森,浅虫湾のフサコケムシからブリオスタチン10という強い抗癌性物質を見いだし,抗エイズ活性もあることが分かった。また,これらの物質には,ホルモン産生活性などの作用の存在も明らかになり,医薬品としての開発の可能性が考えられる。さらに,フロリダ産コケムシから10数種の新規アルカロイドを単離したが,このうちconvolutamydineが,ヒト急性骨髄性白血病細胞HL-60に対し,強力な分化誘導作用を示し,新たな抗癌剤発見の手がかりになる可能性もある。2000年度には,ほぼこれらのアルカロイドの全合成を完成した。これらの結果をふまえ,日本沿岸およびアジア各地の海洋生物について探索が計画されている。さらに,橋本,三浦等が「しんかい6500」,「しんかい2000」により採集した深海生物に対する検討も行い,今までに相模湾産シロウリガイとヘイトウシンカイヒバリガイおよびサツマハオリムシ,さらに巻き貝2種Alyinconcha cf. hesseleriおよびIfremeria nautileiの化学成分の検討を行っている。また,竹内等による南極付近の生物の入手も期待できる現状にある。さらに,新しく速水先生が加わり,洞窟生物の調査・採集が可能となっている。一方,生理活性,薬理作用検討に新たにそれぞれ小宮山博士,林博士,川村教授の協力が得られている。また,一昨年から中国でのフサコケムシの探索が姚新生教授と新たに参加した易楊貨教授によって開始され,かなり大量の生物が採集された。この生物からの活性物質の単離はこれからの大きな仕事であり,その結果が期待される。本年度は今までの生物成分のまとめを行った。特に,日本産ナマコ類成分,沖縄と真鶴で採集した日本産フサコケムシ成分,および深海巻貝2種の成分研究を完成した

Structure and Immunosuppresive Activity of Sterols isolated from The Sagami Gulf Hydrozoa Tubularia sp.

Two immunosuppressive sterols, cholesta-5,23E-diene-3β, 25-diol (trans-liagosterol) (A) and cholesta-5,25 (26)-diene-3β, 24ζ-diol (B) were isolated respectively from the Sagami Gulf Hydrozoa Tubularia sp. by the guide of Mitogen bioassey. Structural determination was accomplished mainly by utilizing high-field (400MHz) 2D-NMR experiments, comparing to the spectra of cholesterol. Although these sterols, A and B, were known as the minor components of marine red alga, the presence in marine animal Hydrozoa such as Tubularia sp. was a new discovery. Sterol A inhibited T lymphocyte proliferation which was induced by plant lectins, concanavalin A (Con-A) and phytochemagglutinin (PHA), more than B lymphocyte proliferation which was induced by lipopolysaccharide (LPS). The activity of sterol B was more week than that of sterol A. On the other hand, by the Mitogen bioassay with hydrocortisone (HC) as a standard inhibitor and related five steroids, β-sitosterol (C), stigmesterol acetate (D), resibufogenin (E), 14,21-epoxy-3 β-hydroxy-5 β-chola-20 (21), 22-dienoic acid (F) and ergosterol (G), the inhibition of sterol A for PHA response was found to be most strong in them. However, for LPS response, the inhibition of hydrocortisone (HC) was more powerful than that of sterol A. Also, the immunosuppresive activity of related steroids, C, D, E and G was little found