Yoshihisa Fujita

Inhibition of Hepatitis C Virus Replication and Viral Helicase by Ethyl Acetate Extract of the Marine Feather Star Alloeocomatella polycladia

Hepatitis C virus (HCV) is a causative agent of acute and chronic hepatitis, leading to the development of hepatic cirrhosis and hepatocellular carcinoma. We prepared extracts from 61 marine organisms and screened them by an in vitro fluorescence assay targeting the viral helicase (NS3), which plays an important role in HCV replication, to identify effective candidates for anti-HCV agents. An ethyl acetate-soluble fraction of the feather star Alloeocomatella polycladia exhibited the strongest inhibition of NS3 helicase activity, with an IC50 of 11.7 µg/mL. The extract of A. polycladia inhibited interaction between NS3 and RNA but not ATPase of NS3. Furthermore, the replication of the replicons derived from three HCV strains of genotype 1b in cultured cells was suppressed by the extract with an EC50 value of 23 to 44 µg/mL, which is similar to the IC50 value of the NS3 helicase assay. The extract did not induce interferon or inhibit cell growth. These results suggest that the unknown compound(s) included in A. polycladia can inhibit HCV replication by suppressing the helicase activity of HCV NS3. This study may present a new approach toward the development of a novel therapy for chronic hepatitis C.

The complete larval development of Sadayoshia edwardsii (37) (Decapoda: Anomura: Galatheidae) described from laboratory‐reared material

The complete larval development of Sadayoshia edwardsii (Miers, 1884) is described and illustrated from laboratory‐reared material. The development comprises four zoeal and one megalopal stages. Diagnostic zoeal characters of Sadayoshia are provided and these are compared with other galatheid genera for which the larval morphology is known. Zoeas of S. edwardsii are readily distinguished from those of other galatheid species by the setation of the maxillular endopod together with the basis and endopod of the first maxilliped. The megalop of S. edwardsii has a flattened, triangular‐shaped rostrum, which differs remarkably from that of the adult. Although the rostral shape resembles that of Galathea megalops, the armature of the lateral margins is different between megalops of the two genera. The present larval study suggests that Sadayoshia is more closely allied to Galathea than to Munida.

THE LONG AND SHORT OF IT: GENETIC VARIATION AND POPULATION STRUCTURE OF THE ANCHIALINE ATYID SHRIMP CARIDINA RUBELLA ON MIYAKO-JIMA, JAPAN

ABSTRACT One of the most threatened ecosystems on many islands may be anchialine habitats, or coastal land-locked water bodies with no surface connection to the sea yet containing brackish water that fluctuates with the tides. To better manage these habitats, it is important to develop a broader understanding of the biodiversity within them since such knowledge plays critical roles in establishing conservation strategies. In this study, the genetic variation and population structure of an anchialine atyid shrimp, Caridina rubella Fujino and Shokita, 1975 was investigated in the Southern Ryukyu Archipelago, Japan. Given a planktotrophic larval stage and its potential amphidromous life cycle, populations of C. rubella on the island of Miyako-jima (to which it is apparently restricted) were hypothesized to have little to no structure across the island. To test this, 61 individuals were collected from four anchialine caves and sequence variation examined at the cytochrome c oxidase subunit I (COI) region of the mitochondrial DNA (mtDNA). Surprisingly, significant genetic structure was exhibited across distances ranging from <20 m to > 10 km. Additionally, deep (∼17% p-distance) genetic divergence correlating with distinct variation in rostrum lengths was found between closely situated, but more-or-less completely isolated, populations. This implies “C. rubella” may actually represent two distinct species on Miyako-jima. Given that this atyid is already listed as a threatened species by the Japanese government, the results presented here are useful in the formulation and implementation of future conservation plans for populations of C. rubella on Miyako-jima.

Multiple colonizations lead to cryptic biodiversity in an island ecosystem: comparative phylogeography of anchialine shrimp species in the Ryukyu Archipelago, Japan.

Archipelagos of the Indo-West Pacific are considered to be among the richest in the world in biodiversity, and phylogeographic studies generally support either the center of origin or the center of accumulation hypothesis to explain this pattern. To differentiate between these competing hypotheses for organisms from the Indo-West Pacific anchialine ecosystem, defined as coastal bodies of mixohaline water fluctuating with the tides but having no direct oceanic connections, we investigated the genetic variation, population structure, and evolutionary history of three caridean shrimp species (Antecaridina lauensis, Halocaridinides trigonophthalma, and Metabetaeus minutus) in the Ryukyu Archipelago, Japan. We used two mitochondrial genes—cytochrome c oxidase subunit I (COI) and large ribosomal subunit (16S-rDNA)—complemented with genetic examination of available specimens from the same or closely related species from the Indian and Pacific Oceans. In the Ryukyus, each species encompassed 2–3 divergent (9.52%–19.2% COI p-distance) lineages, each having significant population structure and varying geographic distributions. Phylogenetically, the A. lauensis and M. minutus lineages in the Ryukyus were more closely related to ones from outside the archipelago than to one another. These results, when interpreted in the context of Pacific oceanographic currents and geologic history of the Ryukyus, imply multiple colonizations of the archipelago by the three species, consistent with the center of accumulation hypothesis. While this study contributes toward understanding the biodiversity, ecology, and evolution of organisms in the Ryukyus and the Indo-West Pacific, it also has potential utility in establishing conservation strategies for anchialine fauna of the Pacific Basin in general.

Taking their breath away: metabolic responses to low-oxygen levels in anchialine shrimps (Crustacea: Atyidae and Alpheidae).

Crustaceans generally act as oxy-regulators, maintaining constant oxygen uptake as oxygen partial pressures decrease, but when a critical low level is reached, ventilation and aerobic metabolism shut down. Cave-adapted animals, including crustaceans, often show a reduced metabolic rate possibly owing in part to the hypoxic nature of such environments. However, metabolic rates have not been thoroughly explored in crustaceans from anchialine habitats (coastal ponds and caves), which can experience variable oxygenic regimes. Here, an atypical oxy-conforming pattern of oxygen uptake is reported in the Hawaiian anchialine atyid Halocaridina rubra, along with other unusual metabolic characteristics. Ventilatory rates are near-maximal in normoxia and did not increase appreciably as PO₂ declined, resulting in a decline in VO₂ during progressive hypoxia. Halocaridina rubra maintained in anoxic waters survived for seven days (the duration of the experiment) with no measureable oxygen uptake, suggesting a reliance on anaerobic metabolism. Supporting this, lactate dehydrogenase activity was high, even in normoxia, and oxygen debts were quickly repaid by an unusually extreme increase in oxygen uptake upon exposure to normoxia. In contrast, four related anchialine shrimp species from the Ryukyu Islands, Japan, exhibited physiological properties consistent with previously studied crustaceans. The unusual respiratory patterns found in H. rubra are discussed in the context of a trade-off in gill morphology for osmoregulatory ion transport vs. diffusion of respiratory gasses. Future focus on anchialine species may offer novel insight into the diversity of metabolic responses to hypoxia and other physiological challenges experienced by crustaceans.

Complete larval development of the rare porcellanid crab, Novorostrum decorocrus Osawa, 1998 (Crustacea: Decapoda: Anomura: Porcellanidae), reared under laboratory conditions

The complete larval development of Novorostrum decorocrus Osawa, 1998, is described and illustrated on the basis of laboratory‐reared material. Two zoeal stages and one megalop stage were recorded. Zoeas of N. decorocrus closely resemble those of N. indicum in the appendage characters, including the endopod of the maxillule with only a single stout seta on the distal margin. This character is unique to Novorostrum zoeas. However, N. decorocrus is distinguished from N. indicum by the setation on the endopod of the maxilla and the basis of the second maxilliped in both zoeal stages. The megalops of N. decorocrus are characterized by having a strongly elongate carapace, and differs considerably from the adults in the structure of the carapace, rostrum and third thoracic sternite, and in the armature of the pereiopods. The larval duration of N. decorocrus suggests that this rare porcellanid is more widely distributed than currently known.

Four Aromatic Sulfates with an Inhibitory Effect against HCV NS3 Helicase from the Crinoid Alloeocomatella polycladia

Bioassay-guided separation of a lipophilic extract of the crinoid Alloeocomatella polycladia, inhibiting the activity of HCV NS3 helicase, yielded two groups of molecules: cholesterol sulfate and four new aromatic sulfates 1–4. The structures of the aromatics were elucidated by spectroscopic analysis in addition to theoretical studies. The aromatic sulfates 1–4 showed moderate inhibition against NS3 helicase with IC50 values of 71, 95, 7, and 5 μM, respectively.

RESURRECTION OF THE GENUS LAOMENES A. H. CLARK, 1919 (DECAPODA, CARIDEA, PALAEMONIDAE)

The palaemonid genus Laomenes is re-established. The type species, Periclimenes (Corniger) ceratophthalmus Borradaile, associated with crinoids, differs from other Periclimenes Costa species at the generic level on the account of the epistome being armed with horns, the posterior rostral carina forming well developed supraorbital eaves, the presence of a supraocular tooth at the edge of the supraocular eaves, the eye with the cornea produced distally, and the mandible with a widened and multidentate incisor process. Three other crinoid associates, P. amboinensis (De Man), P. (Corniger) cornutus Borradaile, and Parapontonia nudirostris Bruce are now placed in the genus Laomenes. The monotypic genus, Parapontonia Bruce is considered to be a junior subjective synonym of Laomenes. A key and a checklist to the species of Laomenes known at present are provided.

Clibanarius ambonensis (Crustacea: Decapoda: Anomura: Diogenidae) from the Ryukyu Islands, south-western Japan

The estuarine hermit crab, Clibanarius ambonensis is reported from Iriomote Island, southern Ryukyu Islands, Japan. This is the first record of the species from outside Indonesian territory. Clibanarius ambonensis was found on prop roots or trunks of Rhizophora stylosa or on rocks adjacent to the trees, which were exposed to the air at low tide time. The habitat seems to distinguish C. ambonensis in the field from the other local congeners inhabiting estuarine and mangrove areas such as C. longitarsus and C. striolatus . The latter two species usually inhabit the sand or mud surface of the estuarine and mangrove areas.

A new species of the genus Vercoia from Okinawa Island, Japan (Crustacea, Decapoda, Caridea, Crangonidae), with descriptions of its zoeal stages

A new crangonid shrimp and its four zoeal stages are described and illustrated in detail from Okinawa Island, Japan. The new species of Vercoia is readily distinguished from V. gibbosa Baker, 1904, V. socotrana Duris, 1992 and V. japonica Komai, 1995, in adult morphology, by the bilobed anterior expansion of the hepatic carina of the carapace, the notched mid-dorsal carina on the fifth abdominal somite, and the presence of the distoventral tooth on the ischium of the second pereopod. The larvae of the new species which are the first larvae of a species assigned to Vercoia to be described, are very similar to those of species of Philocheras, but they differ in the setation of the endopods of the maxillule and maxilla. A key to the adult species of Vercoia is provided.