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排序方式: 共有144条查询结果,搜索用时 15 毫秒
71.
Here we report the first study of clearance rate and respiration rate of a deep living bivalve, Acesta excavata (J.C. Fabricius, 1779) (Mollusca: Limidae). We found that A. excavata had extreme values both for clearance and respiration rates compared to other bivalves. It has the second largest clearance rate ever reported, 13.36 l h− 1 g− 1, and the second lowest value of respiration rate, 0.12 ml O2 h− 1 g− 1. The gill area of 7063 mm2 g− 1 is one of the largest found in bivalves so far. We suggest that these values indicate a physiological adaptation to the low and irregular food supply in the deep sea rather that a specific adaptation to depth. 相似文献
72.
Arakawa S Sato T Sato R Zhang J Gamo T Tsunogai U Hirota A Yoshida Y Usami R Inagaki F Kato C 《Extremophiles : life under extreme conditions》2006,10(4):311-319
Microbial communities inhabiting deep-sea cold seep sediments at the northeastern Japan Sea were characterized by molecular phylogenetic and chemical analyses. White patchy microbial mats were observed along the fault offshore the Hokkaido Island and sediment samples were collected from two stations at the southern foot of the Shiribeshi seamount (M1 site at a depth of 2,961 m on the active fault) and off the Motta Cape site (M2 site at a depth of 3,064 m off the active fault). The phylogenetic and terminal-restriction fragment polymorphism analyses of PCR-amplified 16S rRNA genes revealed that microbial community structures were different between two sampling stations. The members of ANME-2 archaea and diverse bacterial components including sulfate reducers within Deltaproteobacteria were detected from M1 site, indicating the occurrence of biologically mediated anaerobic oxidation of methane, while microbial community at M2 site was predominantly composed of members of Marine Crenarchaeota group I, sulfate reducers of Deltaproteobacteria, and sulfur oxidizers of Epsilonproteobacteria. Chemical analyses of seawater above microbial mats suggested that concentrations of sulfate and methane at M1 site were largely decreased relative to those at M2 site and carbon isotopic composition of methane at M1 site shifted heavier (13C-enriched), the results of which are consistent with molecular analyses. These results suggest that the mat microbial communities in deep-sea cold seep sediments at the northeastern Japan Sea are significantly responsible for sulfur and carbon circulations and the geological activity associated with plate movements serves unique microbial habitats in deep-sea environments. 相似文献
73.
Remme JF Larssen WE Bruheim I Saebø PC Saebø A Stoknes IS 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2006,143(4):459-464
The lipid characterization in tissues from the three deep-sea sharks leafscale gulper shark (Centrophorus squamosus), Portuguese dogfish (Centroscymnus coelolepis) and black dogfish (Centrocyllium fabricii) captured at Hatton Bank in the North Atlantic were examined. The objective was to determine the lipid content and the fatty acid composition in different tissues. In addition, the fatty acid composition in tissues and species was compared. The tissues examined were pancreas, heart, kidney, stomach, spleen and liver. The lipid content was high in liver (40–50%) and ranged from 1% to 5% in the other tissues. The dominant fatty acids were C16:0, C18:1 (n-9), C18:1 (n-7) and C22:6 (n-3) in all tissues. All tissues had a high content of unsaturated fatty acids. 相似文献
74.
75.
In situ enrichment experiments were carried out in the Arctic deep sea (Fram Strait region) to observe the response of benthic
microbial communities to chitin supply. Chambers of a benthic lander were filled in July 2004 with deep-sea sediments enriched
with 1.3–7.0 g m−2 of chitin and the effects of chitin enrichment were assessed on the microbial hydrolytic activity potential, cell number
and community structure after periods of 1 week and 1 year of in situ deployment. The input of chitin had no effect on microbial
abundance and chitobiase activity after 7 days of incubation, whereas community structure in enriched sediments, determined
by terminal restriction fragment length polymorphism analysis of 16S rRNA genes, was different from the controls. After 1 year,
microbial numbers and activity significantly increased in sediments enriched with high chitin concentrations and bacterial
community structure was different from that of the other treatments. The present study suggests that microbial community structure
in Arctic deep-sea sediments can react quickly to sudden large chitin inputs into the sediments and that this appears to precondition
subsequent enhanced growth and enzymatic activity changes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
76.
Careproctus
kidoi sp. nov. is described from the Baffin Bay between Greenland and Canada, in the northern most part of the western North Atlantic.
During a series of bottom trawl surveys conducted in 1988–2004, 22 specimens of an undescribed species of Careproctus were caught at depths between 952 and 1,487 m. It differs from Arctic and North Atlantic congeners in the combination of
the characters: pectoral fin rays 21–26, dorsal fin rays 54–60, anal fin rays 50–54, vertebrae 61–64; sucking disc oval, 4.2–6.6%
SL; teeth simple; pyloric coeca 3–12; head pore formula (2-6-7-1); color light to dark brown, stomach dusky to dark brown,
peritoneum black. It is generally found in deeper waters than the sympatric C. reinhardti. 相似文献
77.
Nitrile metabolising actinomycetes previously recovered from deep-sea sediments and terrestrial soils were investigated for
their nitrile transforming properties. Metabolic profiling and activity assays confirmed that all strains catalysed the hydrolysis
of nitriles by a nitrile hydratase/amidase system. Acetonitrile and benzonitrile, when used as growth substrates for enzyme
induction experiments, had a significant influence on the biotransformation activities towards various nitriles and amides.
The specific activities of selected deep-sea and terrestrial acetonitrile-grown bacteria against a suite of nitriles and amides
were higher than those of the only other reported marine nitrile-hydrolysing R. erythropolis, isolated from a shallow sediment. The increase of nitrile chain length appeared to have negative influence on the nitrile
hydratase activity of acetonitrile-grown bacteria, but the same was not true for benzonitrile-grown bacteria. The nitrile
hydratases and amidases were constitutive in 10 of the 16 deep-sea and terrestrial actinomycetes studied, and one strain showed
an inducible hydratase and a constitutive amidase. Most of the deep-sea strains had constitutive activities and showed some
of the highest activities and broadest substrate specificities of organisms included in this study.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
78.
Takami H Nishi S Lu J Shimamura S Takaki Y 《Extremophiles : life under extreme conditions》2004,8(5):351-356
The thermophilic strains HTA426 and HTA462 isolated from the Mariana Trench were identified as Geobacillus kaustophilus and G. stearothermophilus, respectively, based on physiologic and phylogenetic analyses using 16S rDNA sequences and DNA–DNA relatedness. The genome size of HTA426 and HTA462 was estimated at 3.23–3.49 Mb and 3.7–4.49 Mb, respectively. The nucleotide sequences of three independent -phage inserts of G. stearothermophilus HTA462 have been determined. The organization of protein coding sequences (CDSs) in the two -phage inserts was found to differ from that in the contigs corresponding to each insert assembled by the shotgun clones of the G. kaustophilus HTA426 genome, although the CDS organization in another insert is identical to that in the HTA426 genome. 相似文献
79.
Peek AS Gaut BS Feldman RA Barry JP Kochevar RE Lutz RA Vrijenhoek RC 《Journal of molecular evolution》2000,50(2):141-153
Nucleotide sequences at two mitochondrial genes from 57 individuals representing eight species of deep-sea clams (Vesicomyidae)
were examined for variation consistent with the neutral model of molecular evolution. One gene, cytochrome oxidase subunit
I (COI), deviated from the expectations of neutrality by containing an excess of intraspecific nonsynonymous polymorphism.
Additionally, one species, Calyptogena kilmeri, showed a significant excess of rare polymorphism specifically at the COI locus. In contrast, a second mitochondrial gene,
the large-subunit 16S ribosomal RNA gene (16S), showed little deviation from neutrality either between or within species.
Together, COI and 16S show no deviation from neutral expectations by the HKA test, produce congruent phylogenetic relationships
between species, and show correlated numbers of fixed differences between species and polymorphism within species. These patterns
of both neutral and nonneutral evolution within the mitochondrial genome are most consistent with a model where intraspecific
nonsynonymous polymorphism at COI is near neutrality. In addition to examining the forces of molecular evolution, we extend
hypotheses about interspecific relationships within this family for geographical locations previously unexamined by molecular
methods including habitats near the Middle Atlantic, the Aleutian Trench, and Costa Rica.
Received: 10 March 1999 / Accepted: 13 September 1999 相似文献
80.