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1.
Adolf’s eelpout, Lycodes adolfi, was found at five bottom trawl stations in 2007–2009, on the slope towards the Sofia Deep north of Spitsbergen, at depths of 970–1,220 m and water temperatures below 0°C. Previously, the species has been known from cold and deep waters south of 74°N to both sides of Greenland and in the Norwegian Sea. The present material represents the first records from the Arctic Ocean and may indicate a wider arctic distribution of this species.  相似文献   

2.
La Réunion, one of the three Mascarene islands located in the Indian Ocean, remained devoid of inhabitants until it was first colonized by the French in the middle of the 17th century. The continuous flow of foreign-born slaves and immigrant workers from Africa, India, Southeast Asia, and China to work on coffee and sugar cane plantations led to the island becoming a melting pot of people of multiple ethnic origins. To establish the impact of the different incoming ethnic groups on the present Reunionese gene pool, we have sequenced both hypervariable regions I and II of the mitochondrial DNA molecule, the 9 bp COII/tRNA(Lys) deletion, and four SNPs located in the coding region in a total of 41 samples of the general population, and a further 18 STRs and 35 SNPs on the Y chromosome in 26 of these samples. Our results show that there was a strong sexual bias (asymmetrical gene flow) in the peopling of La Réunion, where admixture events were mainly between male settlers and females from the incoming slave groups. Most of the Y-chromosome gene pool is of European/Middle Eastern ancestry (85%), whereas the mtDNA gene pool is mainly of Indian and East Asian ancestry (70%). The absence of genetic diversity within these two major components of the mtDNA gene pool suggests these populations may have witnessed strong founder effects during the colonization process.  相似文献   

3.
We investigated the reproductive system of the threatened taxon Dombeya acutangula ssp. acutangula Cav. (Sterculiaceae), an endemic tree of the Mascarene archipelago (Indian Ocean). A controlled crossing experiment was performed in two natural populations located in the remnants of the low-elevation dry forest on the island of La Réunion. Active pollination, probably mainly by insects, was necessary for reproduction in this species. Individuals varied in their degree of self-sterility from 0 to 100%. Outcrossing between nearby individuals produced lower seed set than did crosses between more distant individuals within one of the two tested populations. The variation in reproductive success on selfing and in the different types of crosses could result from inbreeding depression causing embryo death, and we provide evidence that progenies from selfing have lower seed size and quality. However, for inbreeding depression to account for the dramatic variation in seed set found in our crossing experiment, the distribution of genetic load and number of lethal factors required appear unrealistic. We favour an alternative interpretation, that D. acutangula possesses an incompatibility system similar to that found in other Sterculiaceae species such as Theobroma cacao L. Such an incompatibility system allows a certain amount of selfing, and different individuals vary in their degree of self-incompatibility. The low success of crosses among close neighbours in one population suggests that there was spatial structure for incompatibility alleles in that population. This could partly explain the decline of the species in fragmented and disturbed habitats, since relatedness at incompatibility loci may increase in small or isolated population and thus reduce mate availability. Received: 2 March 1998 / Accepted: 3 August 1998  相似文献   

4.
The National Science Foundation’s EarthCube End User Workshop was held at USC Wrigley Marine Science Center on Catalina Island, California in August 2013. The workshop was designed to explore and characterize the needs and tools available to the community that is focusing on microbial and physical oceanography research with a particular emphasis on ‘omic research. The assembled researchers outlined the existing concerns regarding the vast data resources that are being generated, and how we will deal with these resources as their volume and diversity increases. Particular attention was focused on the tools for handling and analyzing the existing data, on the need for the construction and curation of diverse federated databases, as well as development of shared, interoperable, “big-data capable” analytical tools. The key outputs from this workshop include (i) critical scientific challenges and cyber infrastructure constraints, (ii) the current and future ocean ‘omics science grand challenges and questions, and (iii) data management, analytical and associated and cyber-infrastructure capabilities required to meet critical current and future scientific challenges. The main thrust of the meeting and the outcome of this report is a definition of the ‘omics tools, technologies and infrastructures that facilitate continued advance in ocean science biology, marine biogeochemistry, and biological oceanography.  相似文献   

5.
《Comptes rendus biologies》2014,337(12):709-716
Previous phylogeographic studies of the humbug damselfish, a widespread Indo-West Pacific coral reef fish, have revealed a split of two main mitochondrial lineages distributed on either side of the Indo-Pacific barrier. This has been interpreted as the result of vicariance. It has been hypothesized that reproductive barriers might currently limit gene flow between humbug damselfish populations from the Indian Ocean and the Pacific Ocean. In this study, we review the published phylogeographic information to update the distribution of the two main mitochondrial lineages of humbug damselfish. The Indian lineage was distributed from the Red Sea to the eastern extremity of the Sunda Shelf while the Pacific lineage, which diverged from the former by 0.6% net nucleotide divergence and diagnostic substitutions at three nucleotide sites at the cytochrome b locus, was distributed east and north of the Sunda Shelf. The two forms, which are also genetically distinct at nuclear loci, were also characterized by distinct pigmentation patterns. We argue that the two forms represent geminate species. Epithet aruanus Linnaeus is maintained for the Pacific Ocean humbug damselfish while epithet abudafur (Forsskål) is here resurrected for the Indian Ocean humbug damselfish. Future studies should focus on the population genetic structure of the transition zone between Dascyllus abudafur and Daruanus.  相似文献   

6.
《Inorganica chimica acta》1986,114(2):141-144
The preparations and properties of tris(dipivaloylmethanato)technetium(III), tris(trifluoroacetylacetonato)technetium(III), and tris(hexafluoroacetonato)technetium(III) are described. The oxidation of the dipivaloyl derivative to tris(dipivaloyl)technetium(IV) hexafluorophosphate was shown to take place readily. Voltammetric studies and magnetic resonance results on the new complexes are reported. The large shifts observed for the complexes seem to be due to a contact interaction.  相似文献   

7.
Boron is an essential nutrient for plants, but it is toxic in excess. Transgenic rice plants expressing an Arabidopsis thaliana borate efflux transporter gene, AtBOR4, at a low level exhibited increased tolerance to excess boron. Those lines with high levels of expression exhibited reduced growth. These findings suggest a potential of the borate transporter BOR4 for the generation of high-boron tolerant rice.  相似文献   

8.
(±)-Homosarkomycin (2) and (±)-rosaprostol (3) were synthesized from (±)-methyl 2-oxo-bicyclo[3.1.0]hexane-1-carboxylate (1) by using the nucleophilic ring opening reaction on the double-activated cyclopropane ring as the key step.  相似文献   

9.
(±)-Lamprolobine, the (+)-enatiomer of which was isolated from the leaves of Lamprolobium fruticosum, and (±)-epilamprolobine were synthesized from δ-valerolactam.  相似文献   

10.
The movement of juvenile loggerhead turtles (n = 42) out-fitted with satellite tags and released in oceanic waters off New Caledonia was examined and compared with ocean circulation data. Merging of the daily turtle movement data with drifter buoy movements, OSCAR (Ocean Surface Current Analyses - Real time) circulation data, and three different vertical strata (0–5 m, 0–40 m, 0–100 m) of HYCOM (HYbrid Coordinate Ocean Model) circulation data indicated the turtles were swimming against the prevailing current in a statistically significant pattern. This was not an artifact of prevailing directions of current and swimming, nor was it an artifact of frictional slippage. Generalized additive modeling was used to decompose the pattern of swimming into spatial and temporal components. The findings are indicative of a positive rheotaxis whereby an organism is able to detect the current flow and orient itself to swim into the current flow direction or otherwise slow down its movement. Potential mechanisms for the means and adaptive significance of rheotaxis in oceanic juvenile loggerhead turtles are discussed.  相似文献   

11.
The equimolar reaction of a β-diketiminate lithium salt LLi(OEt2) [L = HC(CMeNAr)2; Ar = 2,6-iPr2C6H3] with either GeBr2 or SnBr2 in diethyl ether affords the synthetically useful monomeric β-diketiminate-element halides LGeBr (1) and LSnBr (2), respectively. Both are soluble in hydrocarbon solvents, stable in inert atmosphere, and have been characterized by elemental analysis, NMR spectroscopy, and single-crystal X-ray diffraction analysis.  相似文献   

12.
(±)-Licarin A (1) was obtained by oxidative coupling, and its enantiomers, (?)-licarin A (2) and (+)-licarin A (3), were resolved by chiral HPLC. Schistosomicidal and trypanocidal activities of these compounds were evaluated in vitro against Schistosoma mansoni adult worms and trypomastigote forms of Trypanosoma cruzi. The racemic mixture (1) displayed significant schistosomicidal activity with an LC50 value of 53.57 μM and moderate trypanocidal activity with an IC50 value of 127.17 μM. On the other hand, the (?)-enantiomer (2), displaying a LC50 value of 91.71 μM, was more active against S. mansoni than the (+)-enantiomer (3), which did not show activity. For the trypanocidal assay, enantiomer 2 showed more significant activity (IC50 of 23.46 μM) than enantiomer 3, which showed an IC50 value of 87.73 μM. Therefore, these results suggest that (±)-licarin A (1) and (?)-licarin A (2) are promising compounds that could be used for the development of schistosomicidal and trypanocidal agents.  相似文献   

13.
Reaction of the ligand N-methyl-N-((6-pivaloylamido-2-pyridyl)methyl)-N-(2-pyridylethyl)amine (mpppa) with equimolar amounts of [Cu(H2O)6][ClO4]2 or CuCl2 · 2H2O in MeCN afforded mononuclear copper(II) complexes [Cu(mpppa)][ClO4]2 (1) and [Cu(mpppa)Cl2] (2). Crystal structure analysis reveals CuN3O (two pyridyl, an aliphatic amine, and an amide oxygen) coordination in 1 and CuN3Cl2 (two pyridyl, an aliphatic amine, and two chlorides) coordination in 2. Crystal packing diagram of 1 reveals that one of the perchlorate counteranions provides weak coordination to copper(II) centers and in turn the copper(II) centers assume pseudo-six-coordination, generating 1D chain. Notably, one of the copper(II)-coordinated chloride ions in 2 participates in an intramolecular N–H?Cl interaction. Intermolecular C–H?Cl interactions in the solid state generate helical structure. Spectroscopic (IR, UV–Vis, and EPR) and redox properties of the two complexes have been investigated and compared.  相似文献   

14.
Ocean acidification threatens organisms that produce calcium carbonate shells by potentially generating an under‐saturated carbonate environment. Resultant reduced calcification and growth, and subsequent dissolution of exoskeletons, would raise concerns over the ability of the shell to provide protection for the marine organism under ocean acidification and increased temperatures. We examined the impact of combined ocean acidification and temperature increase on shell formation of the economically important edible mussel Mytilus edulis. Shell growth and thickness along with a shell thickness index and shape analysis were determined. The ability of M. edulis to produce a functional protective shell after 9 months of experimental culture under ocean acidification and increasing temperatures (380, 550, 750, 1000 μatm pCO 2, and 750, 1000 μatm pCO 2 + 2°C) was assessed. Mussel shells grown under ocean acidification conditions displayed significant reductions in shell aragonite thickness, shell thickness index, and changes to shell shape (750, 1000 μatm pCO 2) compared to those shells grown under ambient conditions (380 μatm pCO 2). Ocean acidification resulted in rounder, flatter mussel shells with thinner aragonite layers likely to be more vulnerable to fracture under changing environments and predation. The changes in shape presented here could present a compensatory mechanism to enhance protection against predators and changing environments under ocean acidification when mussels are unable to grow thicker shells. Here, we present the first assessment of mussel shell shape to determine implications for functional protection under ocean acidification.  相似文献   

15.
Rivers link oceans with the land, creating global hot spots of carbon processing in coastal seas. Coastlines around the world are dominated by sandy beaches, but beaches are unusual in that they are thought to rely almost exclusively on marine imports for food. No significant connections to terrestrial production having been demonstrated. By contrast, we isotopically traced carbon and nitrogen pathways leading to clams (Donax deltoides) on beaches. Clams from areas influenced by river plumes had significantly different isotope signatures (δ13C: −18.5 to −20.2‰; δ15N: 8.3–10.0‰) compared with clams remote from plumes (δ13C: −17.5 to −19.5‰; δ15N: 7.6–8.7‰), showing that terrestrial carbon and sewage, both delivered in river plumes, penetrate beach food webs. This is a novel mechanism of trophic subsidy in marine intertidal systems, linking the world’s largest shore ecosystem to continental watersheds. The same clams also carry pollution signatures of sewage discharged into rivers, demonstrating that coastal rivers connect ecosystems in unexpected ways and transfer contaminants across the land–ocean boundary. The links we demonstrate between terrigenous matter and the largest of all marine intertidal ecosystems are significant given the immense social, cultural, and economic values of beaches to humans and the predicted consequences of altered river discharge to coastal seas caused by global climate change.  相似文献   

16.
The genus Lecithochirium is briefly discussed and a provisional key to species groups is presented. The following species are described, figured and/or recorded from regions of the southern Indian Ocean: Lecithochirium genypteri from Xiphiurus capensis, Cape Province; L. magnus from Gymnothorax woodwardi and G. javanicus, Western Australia; L. parafusiforme n. sp. from G. flavimarginatus, Natal (type-host and locality) and G. woodwardi, Western Australia; L. macrorchis from G. woodwardi; Leithochirium sp. (ghanense-group?) from Platycephalus bassensis, South Australia; L. kawakawa from Euthynnus affinis and Chrysoblephus anglicus, Natal; Lecithochirium sp. (synodi-group?) from Saurida undosquamis, Natal; L. gymnapisti n. sp. from Gymnapistes marmoratus, Western Australia; L. jaffense from Trachichthodes gerrardi, South Australia and Blennioclinus brachycephalus, Cape Province; Lecithochirium sp. (group unknown) from Alectis ciliaris, Natal.  相似文献   

17.
Microbes drive myriad ecosystem processes, and their viruses modulate microbial-driven processes through mortality, horizontal gene transfer, and metabolic reprogramming by viral-encoded auxiliary metabolic genes (AMGs). However, our knowledge of viral roles in the oceans is primarily limited to surface waters. Here we assess the depth distribution of protein clusters (PCs) in the first large-scale quantitative viral metagenomic data set that spans much of the pelagic depth continuum (the Pacific Ocean Virome; POV). This established ‘core'' (180 PCs; one-third new to science) and ‘flexible'' (423K PCs) community gene sets, including niche-defining genes in the latter (385 and 170 PCs are exclusive and core to the photic and aphotic zones, respectively). Taxonomic annotation suggested that tailed phages are ubiquitous, but not abundant (<5% of PCs) and revealed depth-related taxonomic patterns. Functional annotation, coupled with extensive analyses to document non-viral DNA contamination, uncovered 32 new AMGs (9 core, 20 photic and 3 aphotic) that introduce ways in which viruses manipulate infected host metabolism, and parallel depth-stratified host adaptations (for example, photic zone genes for iron–sulphur cluster modulation for phage production, and aphotic zone genes for high-pressure deep-sea survival). Finally, significant vertical flux of photic zone viruses to the deep sea was detected, which is critical for interpreting depth-related patterns in nature. Beyond the ecological advances outlined here, this catalog of viral core, flexible and niche-defining genes provides a resource for future investigation into the organization, function and evolution of microbial molecular networks to mechanistically understand and model viral roles in the biosphere.  相似文献   

18.
19.
(R)-(+)- and (S)-(?)-dihydrozeatins [(R)-(+)- and (S)-(?)-6-(4-hydroxy-3-methylbutylamino)purines, 1a and 1b] and their ribosides {(?)-6-[(R)-4-hydroxy-3-methylbutylamino]- and (?)-6-[(S)-4-hydroxy-3-methyl-butylamino]-9-β-D-ribofuranosylpurines, 3a and 3b} were synthesized and tested for their cytokinin activity by four bioassay systems, the growth of tobacco callus, the seed germination of lettuce, the fr. wt increase of excised radish cotyledons and the retardation of chlorophyll degradation in radish cotyledons. In tobacco callus bioassay, 1a was more active than 1b. The ribosides 3a and 3b were not less active than their corresponding aglycones 1a and 1b. In other bioassays used the activity followed the order: 1a >3a >1b >3b. In tobacco callus bioassay and lettuce seed germination, trans-zeatin [6-(4-hydroxy-3-methylbut-trans-2-enylamino)purine] showed stronger cytokinin activity than 1a.  相似文献   

20.
A novel synthesis of ( ± )-methyl epijasomonate (2) and the first synthesis of ( ± )-methyl cucurbate (4) were achieved starting from 2-allylcyclohexane-1,3-dione (8). The synthetic epimer 2 had a stronger jasmin flavor than the trans-isomer 1 with 95% purity.  相似文献   

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