Xenobiotic biotransformation in the Pacific oyster (Crassostrea gigas)

1. Oyster visceral mass and gill tissues possessed measurable flavin-containing monooxygenase (FMO) activity. 2. FMO activity was confirmed in visceral mass microsomes by oxygen uptake experiments utilizing various nitrogen and sulfur-containing chemicals along with measurement of N,N-dimethylaniline (DMA) N-oxidase and methimazole oxidation activities. DMA N-oxidase and methimazole oxidation activities also were present in gill microsomes. 3. Excluding oyster gill methimazole oxidation, there were no consistent seasonal differences in FMO activity in oyster gill or visceral mass microsomes. 4. Although lacking spectral evidence for cytochrome P-450, a peak at 418 nm was observed along with NADPH-cytochrome c reductase activity in visceral mass and gill microsomes suggesting the presence of a denatured cytochrome P-450 system. 5. NADPH-independent benzo(a)pyrene hydroxylase (BPH) activity was observed in both oyster visceral mass and gill microsomes suggesting a co-oxidation pathway possibly involving a one electron transfer of oxygen from a lipid hydroperoxide.     

First record of Asteronema rhodochortonoides (Phaeophyceae) for the Pacific Ocean

Morphological observations of a minute, filamentous, branched brown alga epiphytic on Sargassum thun‐bergii (Mertens ex Roth) Kuntze were made on material collected at Tsuyazaki (33°48′N, 130°27′E), Fukuoka Prefecture, southern Japan. This alga was assignable to Asteronema rhodochortonoides (Børgesen) Möller et Parodi in having stellately arranged chloroplasts with several pyrenoids grouped in the center, predominantly apical growth, narrow filaments, and elliptical or broadly elliptical plurilocular zoidangia that are apically or laterally formed on upright filaments. A comparison of partial nuclear small subunit rDNA sequences between the Japanese material and A. rhodochortonoides from the Canary Islands showed only two or three nucleotide differences. This supports our assignment of the Japanese material to this species as a first report for the Pacific Ocean. In laboratory cultures, zoids released from plurilocular zoidangia developed into plants with morphology similar to the field‐collected plants. This cycle repeated without production of unilocular zoidangia in our cultures.     

Barnacles (Cirripedia: Thoracica) from the equatorial East Pacific

Previously unidentified barnacles (Cirripedia: Thoracica) that were collected during the ninth cruise of the R/V Akademik Mstislav Keldysh in the equatorial zone of the East Pacific Ocean from depths of 1422–1490 m are examined. The following species were found in two samples we studied: Amigdoscalpellum costellatum, A. elegans, Arcoscalpellum michelottianum, Annandaleum gruvelii gruvelii, Cristallinaverruca allisoni, and Metaverruca recta. These species are described, illustrated, and compared to the published data. This study extends the previously known areas of distribution of some species and adds further data on their morphology.     

Deepsea herrings (Bathyclupeidae) of the northwestern Pacific ocean

Deepsea herrings of the northwestern Pacific (waters of Japan and Taiwan) are revised. Three species are recognized in this area, and two of them described as new: B. gracilis Fowler, 1938, B. japanotaiwana sp. n., and B. nikparini sp. n. B. japanotaiwana was previously mistakenly identified as the western Atlantic species B. argentea; actually it is especially similar to B. malayana, from which it differs in the bicolor oral cavity and in some meristic characters. B. nikparini is especially close to the Caribbean species B. schroederi, from which it differs in a greater number of developed gill rakers and smaller number of rays in the anal fin.     

Diatom stratigraphy of the late Pleistocene (Brunhes) subarctic Pacific

Three piston cores in the subarctic region of the North Pacific show consistent changes in relative abundance of diatom species throughout the Brunhes magnetic epoch. These events can be used both as stratigraphic markers to subdivide the interval and as indicators of oceanographic conditions. The stratigraphic record shows an acme forA. ochotensis from about 625-350 Kyr (Isotope Stages 15-10); a marked increase in amplitude of abundance fluctuations forR. hebetata 300-0 Kyr (Stages 8-1), the extinction ofR. curvirostris at 276 Kyr (Stage 8), and abundance fluctuations ofD. seminae roughly in phase with the global oxygen isotope record from 450-0 Kyr (Stages 12-1). In the subarctic Pacific, an abrupt change in species abundance is not a reliable indicator of hiatus occurrence. Although details are not clear, there appears to have been a fundamental change of the subarctic gyre during the middle Brunhes (Stages 10-8 time), with more intense glacial intervals and stronger glacial—interglacial contrast occurring after that time. Coarse clastic detritus is not restricted to glacial intervals, suggesting that ice-rafting has occurred throughout the Brunhes interval; peak levels of ice-rafting may occur during ice-growth and decay, as well as during short intervals within a stage.     

Gracilaria vermiculophylla: A western Pacific species of Gracilariaceae (Rhodophyta) first recorded from the eastern Pacific

We report Gracilaria vermiculophylla (Ohmi) Papenfuss from the Pacific coast of North America based on a morphoanatomical revision and comparison of sequences of the nuclear gene coding for the small subunit of ribosomal RNA and the internal transcribed spacers of populations from Baja California, Mexico and Hiroshima, Japan. It is the first convincing report of this species out of its center of distribution in western north Pacific, where it has been considered as a synonym of former ‘G. verrucosa’ records. G. vermiculophylla also occurs in central California as indicated by internal transcribed spacer sequences of a previously unknown Gracilaria Greville material. In the northeastern Pacific G. vermiculophylla is characterized by a robust somewhat vermiform, well‐branched cylindrical thallus, with gradual cell size transition from cortex to medulla, deep spermatangial conceptacles, regular chains of carposporangia and carposporangial initials, downwardly oriented tubular nutritive cells, but rarely with upwardly oriented tubular nutritive cells. In some features of its cystocarp anatomy G. vermiculophylla is related to Gracilariopsis E. Y. Dawson or Hydropuntia Montagne and it is a relevant species for discussions about Gracilariaceae genera.     

Spondylitis in a humpback whale (Megaptera novaeangliae) from the southeast Pacific

A 7.25 m long male humpback whale (Megaptera novaeangliae) with spondylitis was found beached on August 13, 1994 at Ancon, Ecuador (2 degrees 23' S, 80 degrees 47' W). The condition involved at least 11 vertebrae, 7 lumbar (L4 to L11) and 4 caudal (Ca1 to Ca4). Partial fusion of vertebrae was observed as a result of intervertebral bony proliferation, likely impeding full motion. The relatively young age of this specimen and the severity of the deformities suggest an infectious, rather than degenerative, process. The gross findings are most consistent with some type of spondyloarthritis. Although this condition has previously been identified in a number of cetacean species, the pathogenesis, population impact and ecologic implications have not been fully assessed. This is the third case described for humpback whales and the first for a humpback whale from the SE Pacific.     

Ciguatera fish poisoning in the Pacific Islands (1998 to 2008)

Background

Ciguatera is a type of fish poisoning that occurs throughout the tropics, particularly in vulnerable island communities such as the developing Pacific Island Countries and Territories (PICTs). After consuming ciguatoxin-contaminated fish, people report a range of acute neurologic, gastrointestinal, and cardiac symptoms, with some experiencing chronic neurologic symptoms lasting weeks to months. Unfortunately, the true extent of illness and its impact on human communities and ecosystem health are still poorly understood.

Methods

A questionnaire was emailed to the Health and Fisheries Authorities of the PICTs to quantify the extent of ciguatera. The data were analyzed using t-test, incidence rate ratios, ranked correlation, and regression analysis.

Results

There were 39,677 reported cases from 17 PICTs, with a mean annual incidence of 194 cases per 100,000 people across the region from 1998–2008 compared to the reported annual incidence of 104/100,000 from 1973–1983. There has been a 60% increase in the annual incidence of ciguatera between the two time periods based on PICTs that reported for both time periods. Taking into account under-reporting, in the last 35 years an estimated 500,000 Pacific islanders might have suffered from ciguatera.

Conclusions

This level of incidence exceeds prior ciguatera estimates locally and globally, and raises the status of ciguatera to an acute and chronic illness with major public health significance. To address this significant public health problem, which is expected to increase in parallel with environmental change, well-funded multidisciplinary research teams are needed to translate research advances into practical management solutions.     

An ancient prevertebrate Na+-nucleoside cotransporter (hfCNT) from the Pacific hagfish (Eptatretus stouti)

The human concentrative (Na+-linked) plasma membrane transport proteins hCNT1, hCNT2, and hCNT3 are pyrimidine nucleoside-selective (system cit), purine nucleoside-selective (system cif), or broadly selective for both pyrimidine and purine nucleosides (system cib), respectively. All have orthologs in other mammalian species and belong to a gene family (CNT) that has members in insects, nematodes, pathogenic yeast, and bacteria. Here, we report the cDNA cloning and functional characterization of a CNT family member from an ancient marine prevertebrate, the Pacific hagfish (Eptatretus stouti). This Na+-nucleoside symporter, designated hfCNT, is the first transport protein to be characterized in detail in hagfish and is a 683-amino acid residue protein with 13 predicted transmembrane helical segments (TMs). hfCNT was 52, 50, and 57% identical in sequence to hCNT1, hCNT2, and hCNT3, respectively. Similarity to hCNT3 was particularly marked in the TM 4-13 region. When produced in Xenopus oocytes, hfCNT exhibited the transport properties of system cib, with uridine, thymidine, and inosine apparent K(m) values of 10-45 microM. The antiviral nucleoside drugs 3'-azido-3'-deoxythymidine, 2',3'-dideoxycytidine, and 2',3'-dideoxyinosine were also transported. Simultaneous measurement of uridine-evoked currents and radiolabeled uridine uptake under voltage-clamp conditions gave a Na+-to-uridine coupling ratio of 2:1 (cf. 2:1 for hCNT3 and 1:1 for hCNT1/2). The apparent K50 value for Na+ activation was >100 mM. A 50:50 chimera between hfCNT and hCNT1 (TMs 7-13 of hfCNT replaced by those of hCNT1) exhibited hCNT1-like cation interactions, establishing that the structural determinants of cation stoichiometry and binding affinity were located within the carboxy-terminal half of the protein. The high degree of sequence similarity between hfCNT and hCNT3 may indicate functional constraints on the primary structure of the transporter and suggests that cib-type CNTs fulfill important physiological functions.     

Dentition in Pacific walrus (Odobenus rosmarus divergens) calves of the year

The oral cavity and teeth were examined in Pacific walrus calves of the year that died or were harvested on Cape Vancarem and Koluchin Island, the Chukchi Sea, in September to October 2010. The order of gingival eruption of teeth, the resultant dental formula in calves of the year and 1.5-year-old animals, and the dental formula after alveolar eruption of teeth were determined. The number of teeth after gingival eruption in calves of the year did not depend on their body length and sex. The loss of some teeth, mainly incisors, was recorded in individuals aged 5?C6 months. Already at early developmental stages, functional teeth were found to differ significantly from other (rudimentary) teeth in their weight, total size, and the size of apical foramen. Some individuals had milk teeth, which were either gingivally erupted or partly remained within soft tissues. Cases of aberration in dentition that require additional studies were recorded.     

Projected status of the Pacific walrus (Odobenus rosmarus divergens) in the twenty-first century

Extensive and rapid losses of sea ice in the Arctic have raised conservation concerns for the Pacific walrus (Odobenus rosmarus divergens), a large pinniped inhabiting arctic and subarctic continental shelf waters of the Chukchi and Bering seas. We developed a Bayesian network model to integrate potential effects of changing environmental conditions and anthropogenic stressors on the future status of the Pacific walrus population at four periods through the twenty-first century. The model framework allowed for inclusion of various sources and levels of knowledge, and representation of structural and parameter uncertainties. Walrus outcome probabilities through the century reflected a clear trend of worsening conditions for the subspecies. From the current observation period to the end of century, the greatest change in walrus outcome probabilities was a progressive decrease in the outcome state of robust and a concomitant increase in the outcome state of vulnerable. The probabilities of rare and extirpated states each progressively increased but remained <10% through the end of the century. The summed probabilities of vulnerable, rare, and extirpated (P(v,r,e)) increased from a current level of 10% in 2004 to 22% by 2050 and 40% by 2095. The degree of uncertainty in walrus outcomes increased monotonically over future periods. In the model, sea ice habitat (particularly for summer/fall) and harvest levels had the greatest influence on future population outcomes. Other potential stressors had much smaller influences on walrus outcomes, mostly because of uncertainty in their future states and our current poor understanding of their mechanistic influence on walrus abundance.     

The Pacific Notocotylus atlanticus (Digenea: Notocotylidae)

Recently two unidentified Notocotylus species have been recovered from a mallard in Hokkaido, Japan. Preliminary data indicated that one of them may belong to N. atlanticus—a species found in Europe and on the Atlantic coast of North America. Now we have sequenced partial cox1 for several European N. atlanticus isolates and performed a barcode gap analysis. It has shown the conspecificity of European and Japanese worms, bringing up discussion on distribution, transmission and host specificity in this species.     

Species of Minidiscus (Bacillariophyceae) in the Mexican Pacific Ocean

Minidiscus species are the smallest centric diatoms of the marine phytoplankton (with diameters ranging from 1.9 to 7.5 μm), and they may be easily overlooked in routine analyses. Three species of the genus occurred in samples collected in the Mexican Pacific Ocean: Minidiscus trioculatus, M. comicus and M. chilensis. The identification of these species represents the first documented records for the Mexican Pacific: Minidiscus trioculatus and M. chilensis off the west coast of Baja California, and M. comicus in the Gulf of Tehuantepec. Minidiscus trioculatus is considered a cosmopolitan species, M. comicus has a wide distribution in subtropical-temperate waters, and M. chilensis may be mainly regarded as a temperate to cold-water form.     

Pigment distribution in the Pacific region of the Southern Ocean (autumn 1995)

Phytoplankton distribution patterns are still largely unknown for the Pacific region of the Southern Ocean. Pigment distributions were determined by HPLC on 40-m samples collected from the mixed layer during the ANTXII/4 cruise in March–May 1995 aboard RV “Polarstern”. A transect was covered (90°W, from 51°S to 70°S), crossing the Subantarctic Front in the north, the Polar Front, and the Southern Polar Front in the south. Coinciding with high concentrations of silicate, diatoms dominated in the Antarctic waters south of the Polar Front. North of the Polar Front, silicate concentrations dropped to values less than 10 μM. In this area flagellates (Prymnesiophyceae and green algae) were the dominant phytoplankton group. Nutrient depletion of the surface waters near the Southern Polar Front indicated formerly enhanced productivity. These findings confirmed previous observations by the British Sterna expedition, which described locally elevated chlorophyll a biomass near the southern boundary of the Southern Polar Front. We propose a role for supply of bioavailable iron via the front, and emphasise the importance of frontal systems for phytoplankton productivity in the Southern Ocean. Received: 11 June 1997 / Accepted: 16 November 1997     

Status of the eastern Pacific agujon needlefish Tylosurus pacificus (Steindachner, 1876) (Beloniformes: Belonidae)

Tylosurus pacificus (Steindachner, 1876) is confirmed to have full species rank based on: 1) sympatry with T. acus melanotus at Isla Gorgona and in Panamá; 2) level of morphological differentiation in numbers of vertebrae, dorsal and anal fin rays; and 3) level of mtDNA differentiation. The eastern Pacific agujon needlefish is found from the Gulf of California, Mexico, to Peru, including the Galápagos Islands.