Isolation of a highly copper-tolerant yeast, Cryptococcus sp., from the Japan Trench and the induction of superoxide dismutase activity by Cu2+

Thirteen yeast strains were isolated from deep-sea sediment samples collected at a depth of 4500 m to 6500 m in the Japan Trench. Amongst them, strain N6 possessed high tolerance against Cu²⁺ and could grow on yeast extract/peptone/dextrose/agar containing 50 mM CuSO₄. Analysis of the 18S rDNA sequence indicates strain N6 belongs to the genus Cryptococcus. In contrast, the type strain of C. albidus, a typical marine yeast Rhodotorula ingeniosa and Saccharomyces cerevisiae did not grow at high concentrations of CuSO₄. Superoxide dismutase (SOD) catalyzes the scavenging of superoxide radicals. The activity of SOD in cell extract of strain N6 was very weak (<1 mU g^–1 total protein) when the strain was grown in the absence of CuSO₄. However, the activity was stimulated (25.8 mU g^–1 total protein) when cells were grown with 1 mM CuSO₄ and further enhanced to 110 mU g^–1 total protein with 10 mM CuSO₄. Catalase activity was increased only 1.4 or 1.1-fold with 1 mM or 10 mM CuSO₄ in the growth medium, respectively. These results suggest that SOD may have a role in the defensive mechanisms against high concentrations of CuSO₄ in strain N6.     

Trace metals in vertebral columns of deep-sea teleost fish

Deep-sea teleost fish were collected from the Sagami Bay near a deep fissure in the Pacific Ocean. Fish were identified as Chlorophthalmis albatrosis, Engyprosopan xystrias, Satyrichthys hians, Ventrifossa garmani, and Halieutaea stellata. The Etmopterus lucifer is not a teleost, but a deepsea shark. Just after being caught and fixed in neutral 20% formol, the vertebral column was resected and prepared for measurement by inductively coupled plasma-atomic emission spectrometry. Trace elements were found to be Al, Si, Ti, Fe, Cu, Cd, Zn, and Hg at micrograms per gram levels. Major elements were Mg, Ca, P, and S at the milligram per gram level. Some of trace elements, Zn and Hg, were also usually found at this level.     

Reproductive Biology of Southwestern Atlantic Wreckfish, Polyprion americanus (Teleostei: Polyprionidae)

We report on the reproductive biology of southwestern Atlantic wreckfish. Females mature first at 77.9cm total length (TL) (10.4 years) and all are mature by 90cm TL (15.2 years). Males mature first at 74.9cm (9 years) and all are mature by 80cm TL (10.9 years). The wreckfish is a gonochoristic multiple spawner and the gonadal cycle is synchronized at the population level. Spawning occurs from late July to early October along the continental slope (<300m). Ovarian fecundity varies from 3 to 11.9 million (135–311 oocytes×g^–1) and increases exponentially with length. Spawning at western boundary current systems, maintained by homing of adults, is a basic requirement for self-sustaining populations of this species.     

Coral communities of the northwestern Gulf of Aden (Yemen): variation in framework building related to environmental factors and biotic conditions

Coral communities were investigated in the northwestern Gulf of Aden, Yemen, for their composition, structure, and bioconstruction potential. Although no true reef was encountered, high cover coral carpets were found where hard substrate was available. Seven different types of coral communities were differentiated, and both non-framework and framework coral communities were found. Monotypy or oligotypy seem to be consistent characteristics of framework-building coral communities in the study area. Apart from substrate availability, proximity to the upwelling area and exposure were found to be the most important environmental factors influencing coral communities structure, composition, and bioconstruction potential.     

Strategies for Amplification by Polymerase Chain Reaction of the Complete Sequence of the Gene Encoding Nuclear Large Subunit Ribosomal RNA in Corals

The nearly complete nuclear large subunit ribosomal RNA (LSU rRNA) gene in corals was amplified by primers designed from polymerase chain reaction (PCR) strategies. The motif of the putative 3′-terminus of the LSU rRNA gene was sequenced and identified from intergenic spacer (IGS) clones obtained by PCR using universal primers designed for corals. The 3′-end primer was constructed in tandem with the universal 5′-end primer for the LSU rRNA gene. PCR fragments of 3500 bp were amplified for octocorals and non-Acropora scleractinian corals. More than 80% of the Acropora LSU rRNA gene (3000 bp) was successfully amplified by modification of the 5′-end of the IGS primer. Analysis of the 5′-end of LSU rDNA sequences, including the D1 and D2 divergent domains, indicates that the evolutionary rate of the LSU rDNA differs among these taxonomic groups of corals. The genus Acropora showed the highest divergence pattern in the LSU rRNA gene, and the presence of a long branch of the Acropora clade from the other scleractinian corals in the phylogenetic tree indicates that the evolutionary rate of Acropora LSU rDNA might have accelerated after divergence from the common ancestor of scleractinian corals. Received February 17, 2000; accepted June 12, 2000.     

Taxonomy of the deep-sea eel genus, Histiobranchus (Synaphobranchidae, Anguilliformes), with notes on the ecology of H. bathybius in the eastern North Atlantic

The eel genus Histiobranchus Gill occurs benthopelagically over the continental rise and abyss of the World Ocean, primarily beneath temperate and subpolar surface waters. Its generic status within the subfamily Synaphobranchinae is confirmed by comparison of the structure and topography of its cephalic sensory system and skeletal features with Synaphobranchus. At least three species of Histiobranchus are recognized: H. bathybius (panoceanic), H. bruuni (Tasman Sea and waters south-east of New Zealand) and H. australis (two geographical forms; South Atlantic and south-western Indian Ocean, and South Indo-West Pacific Oceans). Collections totalling 319 specimens of H. bathybius from the eastern North Atlantic (1790–5440 m depth) yielded a size range of 99–1370 mm total length ( L _T), with no apparent sexual dimorphism. Length–frequency distributions indicate a mode of juvenile fish at around 100–200 mm L _T and a further two around 600–700 and 1300–1400 mm L _T among adults. Generally smaller fish occur in shallower regions, although the size range is broad over the whole depth range. No apparent trend occurs in the size distribution with latitude over the range 17–54) N. Females outnumber males (1 male : 1·7 females) and both sexes are largely distinguishable from 300 mm L _T. Ripening eggs occur in females from both adult length modes, with running ripe and spent females of very different size indicating iteroparity.     

Characteristics of pullulanases from extremely thermophilic archaea isolated from deep-sea hydrothermal vents

Two out of three extremely thermophilic anaerobic archaea, isolated from deep-sea hydrothermal vents, produced pullulanase activity in the presence of maltose in the growth medium. Enzyme activities were mainly extracellular and characterized by optimum temperatures of 95°C and 80–95°C, optimum pH of 5.0–7.0 and a high degree of thermostability. One strain when grown in a fermenter with maltose as inducer produced pullulanase at 35 U/l. © Rapid Science Ltd. 1998     

Interspecific variation in sustained swimming ability of late pelagic stage reef fish from two families (Pomacentridae and Chaetodontidae)

 Characteristics of the pelagic stages of reef fishes have generally been investigated at the family level, which may mask important differences among species. Here the variation in sustained swimming ability of the late pelagic stages is examined among species, within two families (Pomacentridae and Chaetodontidae). The pomacentrids displayed a 7.5-fold difference in sustained swimming ability across 24 species, while the chaetodontids displayed a 2-fold difference across 10 species. The variation within the Pomacentridae was not related to pelagic larval duration, post-settlement habitat or taxonomy. There was, however, a significant correlation between sustained swimming ability and total length (TL) of individuals (r=0.435, P<0.0001). Differences in the mean distance swum by pomacentrid species, however, was most strongly related to differences in mean wet weight (r=0.814, P<0.0001). When the mean distance swum by species was scaled with respect to mean TL there was still a strong correlation with mean wet weight (r=0.644, P<0.005). Among chaetodontid individuals TL and sustained swimming ability were not correlated (r=−0.004, P=0.978). Furthermore, sustained swimming ability was not significantly related to the trans-oceanic distribution of species in either family. The variation in sustained swimming ability, however, may contribute to explanations of the observed levels of gene flow within populations. Accepted: 24 November 1997     

Seamounts: identity crisis or split personality?

At present, researchers propose that over 14,000 seamounts exist and, like their terrestrial analogues, function like islands. In addition, seamounts are described as oases, biodiversity hotspots, and lush coral/sponge gardens. Here I discuss the extent to which these tenets regarding seamounts may be inappropriate, suffer from a lack of support, and be over-generalizations of a broad range of environmental types encountered on seamounts. Ultimately, for seamount science to progress, we need to challenge our conventional wisdom on these habitats and the extent to which all seamounts function in a similar manner.