共查询到20条相似文献,搜索用时 15 毫秒
1.
Anna-Lisa Wrange Johanna Valero Lisbeth S. Harkestad Øivind Strand Susanne Lindegarth Helle Torp Christensen Per Dolmer Per Sand Kristensen Stein Mortensen 《Biological invasions》2010,12(5):1145-1152
The Pacific oyster (Crassostrea gigas) is an important aquaculture species world-wide. Due to its wide environmental tolerance and high growth rate, it has also
become a successful invader in many areas, leading to major ecosystem changes. Low water temperatures were previously believed
to restrict the establishment of Pacific oysters in Scandinavia. However, recent surveys reveal that the Pacific oyster is
now established in many areas in Scandinavia. We present data on the current distribution, abundance and age-structure in
Denmark, Sweden and Norway. The biomass of oysters in the Danish Wadden Sea increased from 1,056 to 6,264 tonnes between 2005
and 2007. Massive settlements were observed along the Swedish west coast in 2007, with densities >400 oysters per m−2. In Norway, populations are established on the southern coast, and specimens have been found as far north as 60°N. The potential
impacts and probable causes of this recent large-scale establishment are discussed. 相似文献
2.
The Pacific oyster Crassostrea gigas was first introduced as an exotic species by oyster farmers in 1964 in the Oosterschelde estuary (SW Netherlands). The initial
phase is not well documented but first natural spatfall was recorded in 1975. Excessive spatfall occurred in 1976 and this
is considered the start of the expansion phase of the wild oysters. Oyster beds in intertidal and subtidal areas of the Oosterschelde
estuary have been growing since. The development in the intertidal area has been reconstructed by using aerial photography,
validated by ground truth in 2000–2002. In the subtidal areas extensive oyster beds have been detected by using side scan
sonar; on hard substrates along the dikes coverage with oysters up to 90% locally has been recorded by scuba diving surveys.
Expansion has also occurred into adjacent water bodies including the Wadden Sea. By forming resistant reefs the oysters induce
structural changes in the ecosystem. It is concluded that bed area is still expanding while decrease of the fraction live
animals may indicate adjustment of the stock size to the local conditions. 相似文献
3.
Snoussi Mejdi Noumi Emira Messaoud Ali Hajlaoui Hafedh Bakhrouf Amina 《World journal of microbiology & biotechnology》2010,26(11):2037-2046
This study characterized the phenotypic and genetic properties of Vibrio spp. and Aeromonas
hydrophila strains isolated from seawater and mussels (Mytilus
edulis and Crassostrea
gigas) cultured in mollusc farm localized in the lac of Bizerte. The 37 strains (31 strains of V.
alginolyticus, one strain of V. fluvialis, one strain of V. parahaemolyticus and four strains of A.
hydrophila) typed by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) showed a high polymorphism. Most of the isolates
were resistant to at least two antimicrobial agents. All the tested strains were resistant to ampicillin. PCR was used to
detect the presence of eight Vibrio
cholerae virulence genes in the genome of the Vibrio spp. isolates. The results showed a wide dissemination of these genes in the genome of all Vibrio spp. isolates tested. Differentiation of these strains with the ERIC 2-PCR technique revealed no association between the
presence of virulence genes and a particular fingerprinting pattern. 相似文献
4.
This study aimed to investigate intra- and inter-site differences in the epibiota on the European oyster Ostrea edulis of different ages and on hard substrata to assess their contribution to biodiversity. This research has shown that shells
of O. edulis do show higher species diversity than non-living hard substrata and as oysters grow larger epibiotic diversity will increase.
This investigation has revealed that O. edulis possesses biogenic engineering qualities and the value of O. edulis as a vehicle for increasing biodiversity should not be underestimated. Relatively few studies have examined the shell surfaces
of Ostrea edulis, which, together with their associated epifauna provide a large portion of the natural hard substrata for sessile filter-feeding
organisms, including oysters, in coastal and estuarine ecosystems. It can be considered a keystone species which has an influence
on intertidal and subtidal community structures. 相似文献
5.
Semi-sessile Mytilus mussels are used as indicators of climate changes, but their geographic distribution is not sufficiently known in the Arctic. The aim of this study was to investigate the taxonomic status and genetic differentiation of Mytilus populations in a Northwest Greenlandic fjord at Maarmorilik, impacted by contaminations from a former mine. In this study, mussels were collected at three sites differing in exposure to environmental factors. A total of 54 polymorphic SNPs found in the Mytilus EST and DNA sequences analyzed were successfully applied to 256 individuals. The results provided the first evidence for the existence of M. trossulus in Greenland. The mussel from M. trossulus and M. edulis taxa are shown to coexist and hybridize in the fjord. The three studied sites were found to differ significantly in the distribution of taxa with a higher prevalence of M. trossulus in the inner fjord. The identified M. edulis × M. trossulus hybrids mostly had a hybrid index score of about 0.5, indicating a similar number of alleles characteristic for M. trossulus and M. edulis. There was a low number of backcrosses between ‘pure’ taxa and hybrids. This newly discovered hybrid zone between the two taxa is unique in comparison with the Canadian populations. As Mytilus mussels in Greenland hitherto have been regarded as the one taxon M. edulis, the results have importance for biogeography and future monitoring and environmental studies. 相似文献
6.
Klinbunga S Khamnamtong N Tassanakajon A Puanglarp N Jarayabhand P Yoosukh W 《Marine biotechnology (New York, N.Y.)》2003,5(1):27-36
Abstract
Molecular genetic keys for identification of 3 commercially cultured oysters (Crassostrea belcheri, Crassostrea iredalei, and Saccostrea cucullata) in Thailand were developed based on restriction analysis of 18S ribosomal DNA and cytochrome oxidase subunit I (COI). Digestion
of the amplified 18S rDNA with Hinf I unambiguously differentiated Crassostrea oysters from Saccostrea oysters and Striostrea (Parastriostrea) mytiloides. In addition, species-specific restriction fragment length polymorphism patterns of C. belcheri, C. iredalei, and S. cucullata were consistently observed when the gel-eluted COI was digested with Mbo I and Dde I. Thirty composite haplotypes were observed across all individuals. Species-specific composite haplotypes were found in
C. belcheri (AAAA and AAAB), C. iredalei (AABC and AABU), and S. cucullata (BBCD and BBCE), respectively. The most common composite haplotype of COI in C. belcheri (AAAA), C. iredalei (AABC), and S. cucullata (BBCD) was amplified, cloned, and sequenced. Detection of C. belcheri and C. iredalei based on polymerase chain reaction was further developed using more specific primers (HCO2198 and R372) followed by digestion
of a 372-bp product with Mbo I. 相似文献
7.
To understand the background of the strong variation and recent decline of stocks and production of mussels (Mytilus edulis) on tidal flats of the Wadden Sea, we analysed long-term (twice-annual for 26 years) and multi-station (15 sites) estimates
of numbers, mean individual weights, biomass, and annual production on Balgzand, a 50-km2 tidal-flat area in the westernmost part of the Wadden Sea (The Netherlands). Somatic production was estimated from summed
growth increments of soft tissues per half-year period and expressed in ash-free dry mass (AFDM). In adults, positive values
in spring/summer regularly alternated with negative values in autumn/winter, when up to ∼25% (mean: 14%) of individual weight
gains in the preceding season were lost. No weight losses were observed during the first winter of the life of mussels. The
26-year mean of net somatic tissue production P amounted to 5.5 g AFDM m−2 a−1 at a mean biomass B of 3.2 g AFDM m−2; the ratio P/B varied strongly with age composition of the mussel population and ranged between 0.5 and 3.0 a−1 (mean: 1.7). Within the restricted areas of mussel beds, mean biomass and annual production values were two orders of magnitude
higher. In the Wadden Sea, mussel beds cover a typical 1% of extensive tidal flat areas. Numerical densities of recruits showed
straight-line relationships with subsequent life-time year-class production. Once recruits had reached an age of ∼10 months,
their numbers predicted subsequent production within narrow limits. Production per recruit averaged 0.21 g AFDM for 10-mo
recruits and was not related to recruit density. Local variation in annual production varied strongly, with maximal values
between mid-tide and low-tide level, where recruitment was also maximal. Production per recruit was higher at low than at
high intertidal levels. Frequently failing recruitment is indicated as the main cause of declining mussel stocks in the Wadden
Sea. As in other bivalve species, a declining frequency of the occurrence of cold winters appears to govern declining recruitment
success and consequently declining production. 相似文献
8.
Jianfeng Ren Zhanhui Hou Haiyan Wang Ming-an Sun Xiao Liu Bin Liu Ximing Guo 《Marine biotechnology (New York, N.Y.)》2016,18(2):242-254
A large number of Crassostrea oysters are found in Asia-Pacific. While analyses of interspecific variation have helped to establish historical relationships among these species, studies on intraspecific variation are necessary to understand their recent evolutionary history and current forces driving population biology. We resequenced 18 and analyzed 31 mitogenomes of five Crassostrea species from China: Crassostrea gigas, Crassostrea angulata, Crassostrea sikamea, Crassostrea ariakensis, and Crassostrea hongkongensis. Our analysis finds abundant insertions, deletions, and single-nucleotide polymorphisms in all species. Intraspecific variation varies greatly among species with polymorphic sites ranging from 54 to 293 and nucleotide diversity ranging from 0.00106 to 0.00683. In all measurements, C. hongkongensis that has the narrowest geographic distribution exhibits the least sequence diversity; C. ariakensis that has the widest distribution shows the highest diversity, and species with intermediate distribution show intermediate levels of diversity. Low sequence diversity in C. hongkongensis may reflect recent bottlenecks that are probably exacerbated by human transplantation. High diversity in C. ariakensis is likely due to divergence of northern and southern China populations that have been separated without gene flow. The significant differences in mitogenome diversity suggest that the five sister species of Crassostrea have experienced different evolutionary forces since their divergence. The recent divergence of two C. ariakensis populations and the C. gigas/angulata species complex provides evidence for continued diversification and speciation of Crassostrea species along China’s coast, which are shaped by unknown mechanisms in a north–south divide. 相似文献
9.
Recently, Kraan et al. (ICES J Mar Sci 64:1735–1742, 2007) reported that areas in the Wadden Sea selected by mechanical cockle dredgers were of greater zoobenthic diversity than areas
that remained undredged. The present paper attempts to explain this observation, focussing on the elevation-related zoning
of the macrobenthic fauna on tidal flats. Dense beds of cockles Cerastoderma edule occur in a specific intermediate intertidal-height zone where more species are present (and reach their maximal abundance)
than in either lower or higher zones. This coincidence of preferred intertidal zones in many species, including cockles, may
cause the higher species richness (and higher total macrozoobenthic biomass) of the fisher-chosen dredging areas as compared
to other nearby non-dredged tidal-flat areas. 相似文献
10.
Recombination in Mitochondrial DNA of European Mussels <Emphasis Type="Italic">Mytilus</Emphasis> 总被引:1,自引:0,他引:1
Mitochondrial DNA was long believed to be purely clonal and free from recombination. Major phylogenetic studies still depend
on such assumptions. The peculiar genetic system of marine mussels Mytilus in which two divergent mitochondrial genomes exist provides a unique opportunity to study mtDNA recombination. Previous reports
showed the existence of a few haplotypes having very strong recombination signal in the control region of mtDNA. Those recombinant
variants have been found in a Baltic Sea population of Mytilus trossulus as well as in Mytilus galloprovincialis from the Black Sea. In both cases the mosaic genomes switched their transmission route and have been inherited paternally.
In the present study rearranged mtDNA genomes found in all three European Mytilus species are described. The structure of their control region is a result of intra- and intermolecular recombination between
mitochondrial genomes. Together with the phylogenetic reconstruction and geographic distribution, this suggests that two interlineage recombination
events have occurred in the control region of mtDNA of European mussels Mytilus. Contrary to earlier observations, some of the mosaic genomes do not show any gender bias, which has important implications
regarding the transmission and evolution of blue mussel mitochondrial genomes. 相似文献
11.
Ornithological surveys conducted over the Pechora Sea (the southeastern part of the Barents Sea) in the 1990 s revealed huge
non-nesting flocks of marine ducks, the largest in the European North. Especially dense waterfowl aggregations are constantly
observed at the shallows near Dolgij Island during molting period and migration to wintering places. All the marine ducks
flocking there are specialized benthos feeders predominantly consuming mussels Mytilus edulis. At the same time, numerous previous benthic studies in the Pechora Sea did not reveal mussels near Dolgij Island where benthic
biomass was somewhat lower than in the adjacent areas (Denisenko in Mar Ecol Prog Ser 258:109–123. 2003) which left the food
source for these abundant bird flocks enigmatic. In the course of an expedition in summer 2007 we found subtidal populations
of M. edulis in shallows to the southwest of Dolgij Island. These populations were confined to a coastal zone and were characterized by
a highly disjunct distribution with the biomass reaching up to 4 kg m−2. We describe these subtidal populations as well as an intertidal mussel population on the western shore of Dolgij Island. 相似文献
12.
Background
Oysters are morphologically plastic and hence difficult subjects for taxonomic and evolutionary studies. It is long been suspected, based on the extraordinary species diversity observed, that Asia Pacific is the epicenter of oyster speciation. To understand the species diversity and its evolutionary history, we collected five Crassostrea species from Asia and sequenced their complete mitochondrial (mt) genomes in addition to two newly released Asian oysters (C. iredalei and Saccostrea mordax) for a comprehensive analysis. 相似文献13.
Laura Payton Mickael Perrigault Jean-Paul Bourdineaud Anjara Marcel Jean-Charles Massabuau Damien Tran 《Marine biotechnology (New York, N.Y.)》2017,19(4):361-371
RNA interference is a powerful method to inhibit specific gene expression. Recently, silencing target genes by feeding has been successfully carried out in nematodes, insects, and small aquatic organisms. A non-invasive feeding-based RNA interference is reported here for the first time in a mollusk bivalve, the pacific oyster Crassostrea gigas. In this Trojan horse strategy, the unicellular alga Heterocapsa triquetra is the food supply used as a vector to feed oysters with Escherichia coli strain HT115 engineered to express the double-stranded RNA targeting gene. To test the efficacy of the method, the Clock gene, a central gene of the circadian clock, was targeted for knockout. Results demonstrated specific and systemic efficiency of the Trojan horse strategy in reducing Clock mRNA abundance. Consequences of Clock disruption were observed in Clock-related genes (Bmal, Tim1, Per, Cry1, Cry2, Rev.-erb, and Ror) and triploid oysters were more sensitive than diploid to the interference. This non-invasive approach shows an involvement of the circadian clock in oyster bioaccumulation of toxins produced by the harmful alga Alexandrium minutum. 相似文献
14.
A noninvasive method was applied to study the heart rates of the White Sea bivalves Mytilus edulis and Modiolus modiolus in a long-term field experiment during the winter. No cardiac arrest and relatively high levels of cardiac activity (5.26
and 3.49 beats/min, respectively) were observed in both species. Oscillations of heart rate and signal amplitude with wavelengths
of 3 to 6, 9 to 16, and 18 to 24 h were found. The oscillations of heart rate and cardiac signal amplitude occurred simultaneously
and were connected with the tidal cycle only in the case of the short-term rhythms. 相似文献
15.
16.
Cláudio M. R. Melo Francisco C. Silva Carlos Henrique A. M. Gomes Antonio M. Solé-Cava Cristiano Lazoski 《Biological invasions》2010,12(3):441-449
We report on the invasion of Brazil by the Pacific oyster Crassostrea gigas, and discuss the likely routes of invasion. Because this phenotypically diverse oyster sometimes resembles the native species
C. brasiliana and C. rhizophorae, its invasion went unnoticed until it was detected through the analysis of DNA sequences for ribosomal 16S and the ribosomal
second internal transcribed spacer. C. gigas was found amongst the native species in oyster banks up to 100 km south of oyster farms in South Brazil. Under most circumstances,
water temperatures in the coastal southerly Brazil current would be too high to allow for the establishment of stable populations
of C. gigas, but the production of spat in oyster farm laboratories has probably selected for resistance to warmer temperatures, which
would promote invasion by C. gigas. 相似文献
17.
The common cord-grass Spartina anglica, a fertile hybrid of S. maritima and S. alterniflora, was planted in the European Wadden Sea extensively during the late 1920s and 1930s to promote sediment accretion. After
establishment, it colonised as a pioneer plant in the upper tidal zone, where it occurs frequently in coherent swards at the
seaward front of saltmarshes and in patches on the tidal flats. Often, a conspicuous, almost monotypic, belt of S. anglica is formed. Over the last two decades, an increase in abundance and accelerated spread of S. anglica was observed, possibly promoted by warmer spring temperatures. This alien species may benefit from global warming, and there
is considerable concern about its harmful impacts on the native biocoenoses and native biodiversity of the unique Wadden Sea
ecosystem, encompassing effects on hydromorphodynamics and coastal protection. For a definitive assessment, however, an adequate
quantification and comparison of documented and potential effects of S. anglica is important, but currently unavailable. Consequently, no management strategy exists for the prevention or restoration of
the Wadden Sea ecosystem. Thus, the development of an alien species plan on the level of the Trilateral Cooperation on the
Protection of the Wadden Sea is essential. 相似文献
18.
Mycological investigation of the Pacific (giant) oyster Crassostrea gigas (Thunberg, 1793) (Bivalvia) from the Peter the Great Bay of the Sea of Japan was carried out. The taxonomic composition of
filamentous fungi associated with C. gigas was studied. The taxonomic composition of the fungi associated with the giant oyster included 22 species of filamentous fungi
of which 17 species were identified. The latter belonged to six genera: Alternaria, Aspergillus, Botrytis, Fusarium, Penicillium, and Trichoderma. The distribution of filamentous fungi in the internal organs of the bivalve mollusk was studied. 相似文献
19.
The rhodophytes Mastocarpus stellatus and Chondrus crispus occupy the lower intertidal zone of rocky shores along North Atlantic coastlines, with C. crispus generally occurring slightly deeper. Consequently, M. stellatus is exposed to more variable environmental conditions, related to a generally higher stress tolerance of this species. In order to extend our understanding of seasonal modulation of stress tolerance, we subjected local populations of M. stellatus and C. crispus from Helgoland, North Sea, to short-term high-light stress experiments over the course of a year (October 2011, March, May and August 2012). Biochemical analyses (pigments, antioxidants, total lipids, fatty acid compositions) allowed to reveal mechanisms behind modulated high-light tolerances. Overall, C. crispus was particularly more susceptible to high-light at higher water temperatures (October 2011 and August 2012). Furthermore, species-specific differences in antioxidants, total lipid levels and the shorter-chain/longer-chain fatty acid ratio (C14 + C16/C18 + C20) were detected, which may enhance the tolerance to high-light and other abiotic stress factors in M. stellatus, so that this species is more competitive in the highly variable upper intertidal zone compared to C. crispus. Since the high-light tolerance in C. crispus seemed to be affected by water temperature, interactions between both species may be impacted in the future by rising mean annual sea surface temperature around the island of Helgoland. 相似文献
20.
Ismael Cross Silvia Portela-Bens Aglaya García-Angulo Manuel A. Merlo María E. Rodríguez Thomas Liehr Laureana Rebordinos 《BMC genetics》2018,19(1):104