Molecular analyses of the sediment of the 11000-m deep Mariana Trench

We have obtained sediment samples from the world's deepest sea-bottom, the Mariana Trench challenger point at a depth of 10 898 m, using the new unmanned submersible Kaiko. DNA was extracted from the sediment, and DNA fragments encoding several prokaryotic ribosomal RNA small-subunit sequences and pressure-regulated gene clusters, typically identifed in deep-sea adapted bacteria, were amplifed by the polymerase chain reaction. From the sequencing results, at least two kinds of bacterial 16S rRNAs closely related to those of the genus Pseudomonas and deep-sea adapted marine bacteria, and archaeal 16S rRNAs related to that of a planktonic marine archaeon were identifed. The sequences of the amplifed pressure-regulated clusters were more similar to those of deep-sea barophilic bacteria than those of barotolerant bacteria. These results suggest that deep-sea adapted barophilic bacteria, planktonic marine archaea, and some of the world's most widespread bacteria (the genus Pseudomonas) coexist on the world's deepest sea-bottom. Received: October 10, 1996 / Accepted: March 3, 1997     

Taxonomic studies of deep-sea barophilic Shewanella strains and description of Shewanella violacea sp. nov.

Several barophilic Shewanella species have been isolated from deep-sea sediments at depths of 2,485– 6,499 m. From the results of taxonomic studies, all of these isolates have been identified as strains of Shewanella benthica except for strain DSS12. Strain DSS12 is a member of a novel, moderately barophilic Shewanella species isolated from the Ryukyu Trench at a depth of 5,110 m. On Marine Agar 2216 plates, this organism produced a violet pigment, whereas the colonies of other isolates (S. benthica) were rose-colored. Phylogenetic analysis based on 16 S ribosomal RNA gene sequences showed that strain DSS12 represents a separate lineage within the genus Shewanella that is closely related to S. benthica and particularly to the members of the Shewanella barophiles branch. The temperature range for growth and some of the biochemical characteristics indicate that strain DSS12 differs from other Shewanella species. Furthermore, strain DSS12 displayed a low level of DNA similarity to the Shewanella type strains. Based on these differences, it is proposed that strain DSS12 represents a new deep-sea Shewanella species. The name Shewanella violacea (JCM 10179) is proposed. Received: 15 May 1998 / Accepted: 15 July 1998     

Taxonomic studies of extremely barophilic bacteria isolated from the Mariana Trench and description of Moritella yayanosii sp. nov., a new barophilic bacterial isolate

We have isolated two strains of extremely barophilic bacteria from sediment collected from the world's deepest ocean floor in the Mariana Trench, Challenger Deep, at a depth of 10898m [Kato C, Li L, Nogi Y, Nakamura Y, Tamaoka J, Horikoshi K (1998) Appl Environ Microbiol 64:1510-1513]. One strain, DB21MT-2, was identified as a strain of Shewanella benthica, and the other strain, DB21MT-5, is closely affiliated with members of the genus Moritella on the basis of 16S rDNA sequence analysis. The hybridization values for DNA-DNA relatedness between DB21MT-5 and the Moritella reference strains were significantly lower than that accepted as the phylogenetic definition of a species. Based on this and other taxonomic differences, strain DB21MT-5 appears to represent a novel obligately barophilic deep-sea Moritella species. The name Moritella yaynanosii (JCM 10263) is proposed. This is the first proposed species of obligately barophilic bacteria of the genus Moritella.     

<Emphasis Type="Italic">Foxtosognus rarus</Emphasis> gen. n., sp. n.—A new genus and species of copepods (Copepoda: Calanoida) from the abyssopelagic zone of the Kuril-Kamchatka Trench

A female of Foxtosognus rarus gen. n., sp. n., a new genus and species of copepods, is described from the abyss of the Kuril-Kamchatka Trench. The new genus is placed in the family Arctokonstantinidae, whose diagnosis is emended and supplemented with the following characters: mandibular basis with one to two setae; mandibular endopod one without setae; maxillular distal basal endite plus endopod with two to four setae or without setae. The features that distinguish Foxtosognusgen. n. from other representatives of this family are as follows: mandibular palp with a long endopod segment one, endopod segment two with seven setae, and exopod segment five with two setae; maxillula with distal basal endite lacking setae and separated from endopod bearing three setae; maxillular precoxal arthrite with seven to eight setae and exopod with four setae; maxilliped syncoxa without setae on precoxal endites and endopod of three segments. The genera Sognocalanus and Foxtonia earlier included in the Spinocalanidae are herein transferred to the Arctokonstantinidae.     

Mollusk collecting and environmental change during the Prehistoric Period in the Mariana Islands

Archaeological research in the Mariana Islands has revealed changes in mollusk collecting during the Prehistoric Period (approximately 1500 BC to AD 1521). The earliest people at Tumon Bay, Guam and Chalan Piao, Saipan collected mostly bivalves, especially the arc clam Anadara antiquata. After several hundred years, they no longer collected A. antiquata, but collected smaller bivalves instead. By AD 1000, they collected mostly gastropods, primarily the coral reef species Strombus gibberulus gibbosus. One possible explanation is that the people preferred the large arc clam but overharvested it until they were forced to eat the smaller bivalves and then the snails. However, recent evidence in the form of mangrove wood and mangrove pollen supports another explanation, one of non-anthropogenic environmental change. In this case, the relative sea-level decline, which took place in the Marianas within the last 4,000 years, caused the demise of mangrove habitats and of the arc clam at Tumon Bay, Guam and Chalan Piao, Saipan. As mangrove habitats were diminished by sea-level decline, collecting effort shifted to coral reefs, and S. gibberulus gibbosus was harvested throughout the remainder of the Prehistoric Period and into the Historic Period. Southern Guam is the only area in the Marianas in which A. antiquata increased in abundance during the Prehistoric Period. The same types of evidence, mangrove wood and mangrove pollen, indicate that, in contrast to the situation at Tumon Bay and Chalan Piao, mangroves increased in abundance in southern Guam.     

Microbial Diversity in Sediments Collected from the Deepest Cold-Seep Area, the Japan Trench

The Japan Trench land slope at a depth of 6,400 m is the deepest cold-seep environment with Calyptogena communities. Sediment samples from inside and beside the Calyptogena communities were collected, and the microbial diversity in the sediment samples was studied by molecular phylogenetic techniques. From DNA extracted directly from the sediment samples, 16S rDNAs were amplified by the polymerase chain reaction method. The sequences of the amplified 16S rDNAs selected by restriction fragment length polymorphism analysis were determined and compared with sequences in DNA databases. The results showed that 33 different bacterial 16S rDNA sequences from the two samples analyzed fell into similar phylogenetic categories, the α-, γ-, δ-, and ɛ-subdivisions of Proteobacteria, Cytophaga, and gram-positive bacteria; some of the 16S rDNA sequences were common to both samples. δ- and ɛ-Proteobacteria-related sequences were abundant in both sediments. These sequences are mostly related to sulfate-reducing or sulfur-reducing bacteria and epibionts, respectively. Eight different archaeal 16S rDNA sequences were cloned from the sediments. The majority of the archaeal 16S rDNA sequences clustered in Crenarchaeota and showed high similarities to marine group I archaeal rDNA. A Methanococcoides burtonii–related sequence obtained from the sediment clustered in the Euryarchaeota indicating that M. burtonii–related strains in the area of Calyptogena communities may contribute to production of methane in this environment. From these results, we propose a possible model of sulfur circulation within the microbial community and that of Calyptogena clams in the cold-seep environment. Received June 15, 1998; accepted November 10, 1998.     

A conversation with Mariana Wolfner,newly inducted member of the National Academy of Sciences

Molecular Reproduction and Development is delighted to announce that editorial board member Mariana F. Wolfner has been elected to the National Academy of Sciences. Here, Dr Wolfner is interviewed by two of her former postdocs. She discusses her path to studying reproduction and her career as a researcher and mentor.     

Epidemiology of areca (betel) nut use in the mariana islands: Findings from the University of Guam/University of Hawai`i cancer center partnership program

BackgroundAreca (betel) nut is considered a Group 1 human carcinogen shown to be associated with other chronic diseases in addition to cancer. This paper describes the areca (betel) nut chewing trend in Guam, and health behaviors of chewers in Guam and Saipan.MethodsThe areca (betel) nut module in the Guam Behavioral Risk Factor Surveillance Survey was used to calculate the 5-year (2011–2015) chewing trend. To assess the association between areca (betel) nut chewing and health risks in the Mariana Islands, a cross-section of 300 chewers, ≥18 years old, were recruited from households in Guam and Saipan. Self-reported socio-demographics, oral health behaviors, chronic disease status, diet, and physical activity were collected. Anthropometry was measured. Only areca (betel) nut-specific and demographic information were collected from youth chewers in the household.ResultsThe 5-year areca (betel) nut chewing prevalence in Guam was 11% and increased among Non-Chamorros, primarily other Micronesians, from 2011 (7%) to 2015 (13%). In the household survey, most adult chewers (46%) preferred areca nut with betel leaf, slaked lime, and tobacco. Most youth chewers (48%) preferred areca nut only. Common adult chronic conditions included diabetes (14%), hypertension (26%), and obesity (58%).ConclusionThe 5-year areca (betel) nut chewing prevalence in Guam is comparable to the world estimate (10–20%), though rising among Non-Chamorros. Adult and youth chewers may be at an increased risk for oral cancer. Adult chewers have an increased risk of other chronic health conditions. Cancer prevention and intervention strategies should incorporate all aspects of health.