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F. Fontana 《Zeitschrift fur angewandte Ichthyologie》2002,18(4-6):226-233
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Cryptic species are numerous in the marine environment. The brittle star Ophioderma longicauda is composed of six mitochondrial lineages, encompassing brooders, which form a monophyletic group, and broadcasters, from which the brooders are derived. To clarify the species limits within O. longicauda, we compared the reproductive status of the sympatric lineages L1 and L3 (defined after sequencing a portion of the mitochondrial gene COI) during the month of May in Greece. In addition, we genotyped a nuclear marker, intron i51. Each L3 female was brooding, whereas all L1 specimens displayed full gonads, suggesting temporal pre-zygotic isolation between brooders and broadcasters. Statistical differences were found among lineages in morphology and bathymetric distribution. Finally, the intron i51 was polymorphic in L1 (60 individuals), but monomorphic in L3 (109 individuals), confirming the absence of gene flow between brooders and broadcasters. In conclusion, the broadcasting lineage L1 and the brooding lineage L3 are different biological species. 相似文献
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从施氏鲟(Acipenser schrencki)、小体鲟(Acipenser ruthenus)、西伯利亚鲟(Acipenser baeri)、哲罗鲑(Hucho taimen)和金鳟(Oncorhynchus mykiss)五种鱼类卵黄中分离、纯化Ig,并对其分子结构进行了初步研究。结果表明:五种鱼类卵中Ig的分子量分别为施氏鲟524kD、小体鲟468kD、西伯利亚鲟475kD、哲罗鲑为490kD,金鳟498kD,其Ig重链的相对分子量相同,约为97kD。轻链的相对分子量各不相同,施氏鲟为27kD,小体鲟28.5kD,西伯利亚鲟30kD,哲罗鲑28.5kD和金鳟16kD。其中西伯利亚鲟、施氏鲟和小体鲟Ig等电点约为5.85,哲罗鲑和金鳟的Ig等电点约为6.55,其蛋白质结构上具有一定的相似性,且均为糖蛋白 相似文献
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Background
The analysis of biological data is greatly enhanced by existing or emerging databases. Most existing databases, with few exceptions are not designed to easily support large scale computational analysis, but rather offer exclusively a web interface to the resource. We have recognized the growing need for a database which can be used successfully as a backend to computational analysis tools and pipelines. Such database should be sufficiently versatile to allow easy system integration. 相似文献7.
Qiwei Wei Fu'en Ke Jueming Zhang Ping Zhuang Junde Luo Rueqiong Zhou Wenhua Yang 《Environmental Biology of Fishes》1997,48(1-4):241-255
This paper reviews five of the eight species of acipenseriforms that occur in China, chiefly those of the Amur and Yangtze rivers. Kaluga Huso dauricus and Amur sturgeon Acipenser schrenckii are endemic to the Amur River. Both species still support fisheries, but stocks are declining due to overfishing. Acipenseriformes of the Yangtze River are primarily threatened by hydroelectric dams that block free passage to spawning and feeding areas. The Chinese paddlefish Psephurus gladius now is rare in the Yangtze River system, and its spawning activities were severely limited by completion of the Gezhouba Dam in 1981. Since 1988, only 3–10 adult paddlefishes per year have been found below the dam. Limited spawning still exists above the dam, but when the new Three Gorges Dam is complete, it will further threaten the paddlefish. Artificial propagation appears to be the only hope for preventing extinction of P. gladius, but it has yet to be successfully bred in captivity. Dabry's sturgeon A. dabryanus is a small, exclusively freshwater sturgeon found only in the Yangtze River system. It is concentrated today in reaches of the main stream above Gezhouba Dam. The fishery has been closed since 1983, but populations continue to decline. Acipenser dabryanus has been cultured since the 1970s, and holds promise for commercial aquaculture; availability of aquacultural methods offers hope for enhancing natural populations. The Chinese sturgeon A. sinensis occurs in the Yangtze and Pearl rivers and seas of east Asia. There is still disagreement about the taxonomy of the Pearl and Yangtze River populations. The Yangtze River population is anadromous. Adults begin spawning at about age 14 years (males) and 21 years (females), and adults spend over 15 months in the river for reproduction. Spawning sites of A. sinensis were found every year since 1982 below the Gezhouba Dam, but it seems that insufficient suitable ground is available for spawning. Since 1983, commercial fishing has been prohibited but more measures need to be taken such as establishing protected areas and characterizing critical spawning, summering and wintering habitats. 相似文献
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Etti S Hails R Schäfer SM De Michelis S Sewell HS Bormane A Donaghy M Kurtenbach K 《Applied and environmental microbiology》2003,69(5):3008-3010
The distribution of Borrelia burgdorferi sensu lato genospecies in questing Ixodes ricinus ticks from ecologically distinct habitats in Latvia was analyzed. A significant variation in the frequency of the genospecies across sites was observed, pointing to the importance of the host community in the ecology of Lyme borreliosis. 相似文献
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Samantha Twiname Asta Audzijonyte Julia L. Blanchard Curtis Champion Thibaut de la Chesnais Quinn P. Fitzgibbon Hannah E. Fogarty Alistair J. Hobday Rachel Kelly Kieran J. Murphy Michael Oellermann Patricia Peinado Sean Tracey Cecilia Villanueva Barrett Wolfe Gretta T. Pecl 《Ecography》2020,43(12):1764-1778
Climate-driven species redistribution is pervasive and accelerating, yet the complex mechanisms at play remain poorly understood. The implications of large-scale species redistribution for natural systems and human societies have resulted in a large number of studies exploring the effects on individual species and ecological communities worldwide. Whilst many studies have investigated discrete components of species redistribution, the integration required for a more complete mechanistic understanding is lacking. In this paper, we provide a framework for synthesising approaches to more robustly understand and predict marine species redistributions. We conceptualise the stages and processes involved in climate-driven species redistribution at increasing levels of biological organisation, and synthesize the laboratory, field and modelling approaches used to study redistribution related processes at individual, population and community levels. We then summarise links between scales of biological organisation and methodological approaches in a hierarchical framework that represents an integrated mechanistic assessment of climate-driven species redistributions. In a rapidly expanding field of research, this framework provides direction for: 1) guiding future research, 2) highlighting key knowledge gaps, 3) fostering data exchange and collaboration between disciplines and 4) improving shared capacity to predict and therefore, inform the proactive management of climate impacts on natural systems. 相似文献
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Isaac I. Wirgin Joseph E. Stabile John R. Waldman 《Environmental Biology of Fishes》1997,48(1-4):385-398
Sturgeon and paddlefish populations worldwide have declined because of anthropogenic influences. The structure and magnitude of genetic diversity of natural populations serves to buffer these fishes against environmental variation and should be maintained. Modern molecular biological techniques provide the ability to sensitively characterize and quantify the extent of genetic variation in natural populations. We provide a summary of those problems in sturgeon population biology that are amenable to investigation with DNA approaches, and their applications to date. These have included genetic identification and discrimination of taxa, identification of hybrids, stock identification, mixed-stock analysis, and estimation of gene flow and homing fidelity. To date, almost all studies have been restricted to North American fauna. Improvements to these technologies, including nondestructive sampling, should permit more widespread application of molecular approaches to problems of acipenseriform conservation. We suggest that the use of more sensitive molecular tools such as analyses of hypervariable repetitive and non-coding single copy nuclear DNA may assist management even in those taxa which exhibit overall low levels of genetic diversity. 相似文献
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Grunina AS Rekubratskiĭ AV Tsvetkova LI Barmintseva AE Vasil'eva ED Kovalev KV Poluéktova OG 《Ontogenez》2011,42(2):133-145
Dispermic androgenesis was used to produce, for the first time, an androgenetic progeny of the Siberian sturgeon (Acipenser baerii) and the androgenetic nuclear cytoplasmic hybrids (Siberian sturgeon, A. baerii x Russian sturgeon, A. gueldenstaedtii) using cryopreserved sperm. Microsatellite DNA analysis confirmed exclusively paternal inheritance in the androgenetic progeny of Siberian sturgeon. Heterozygotes for certain microsatellite loci were detected among the androgenetic hybrids, thereby confirming a dispermic nature of androgenesis. According to the data of comparative morphological analysis, the obtained androgenetic hybrid, by the age of 15 months old, was completely identical to the paternal species. Both a female and a male were detected in the androgenetic sturgeon progenies, which is of interest for producing bisexual progenies via androgenesis. The data of this study confirm the feasibility of dispermic androgenesis using cryopreserved sperm to preserve and recover the gene pools of endangered sturgeon species. 相似文献
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A new, partially deficient transferrin variant in the pig 总被引:1,自引:0,他引:1
A new, partially deficient transferrin variant (TF F) was found in serum samples of a wild boar and his offspring from crossing with Pietrain sows. Family analyses confirmed its genetic control by a codominant allele, TFF. Finding of this new variant has brought the total number of pig transferrin variants to nine (F, I, A, B, C, X, D', E, D). 相似文献
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Arnaudova Zh Bileva T 《Communications in agricultural and applied biological sciences》2011,76(3):355-361
Vine is a traditional branch of plant growing in Bulgaria. The exact location of the vine culture is a specific complex of environmental factors influencing its development, such as climate, soil, landscape and traditions of the region. GIS is a platform to better manage, evaluate and present spatial data in a useful visual form. It's improves the decision-making by combining data with accurate location and management the vineyards. In the present survey were studied and analyzed the factors in choosing an appropriate location for the cultivation of vine varieties in selected regions of Plovdiv. Climatic and soil characteristics, topography and environmental factors as well as presence of virus vector nematodes from family Longidoridae in creating the vines through GIS spatial analysis are taken into account. 相似文献
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HEIKE ZIMMERMANN HENRIK VON WEHRDEN MARIA A. DAMASCOS DONALDO BRAN ERIK WELK DANIEL RENISON ISABELL HENSEN 《Austral ecology》2011,36(7):870-880
Prediction of invasive species spread helps to plan management actions. We performed a risk assessment by quantifying habitat invasibility, predicted the potential distribution of an invasive species using the Maxent modelling program and confirmed patterns using detailed field studies. Our study was conducted in southern Argentina, Patagonia, where large areas are already invaded by the European shrub Rosa rubiginosa. A total of 163 R. rubiginosa locations served as ground truth data, and predictors were obtained from the spaceborne sensor Landsat 5. Based on the Maxent Method (area under the receiver operating characteristic curve 0.8), the habitat invasibility map covered about 5000 km2. Our model revealed that R. rubiginosa has the potential to invade 36% of the area along a steep precipitation gradient (target region 600–1400 mm per year). The Tasseled Cap brightness index and the normalized vegetation index explained most of the variance in our model, followed by the Tasseled Cap greenness and wetness indices, which can be interpreted as indicators of disturbance. Highest levels of invasibility were predicted for urban areas, along roads and rivers, on pastures, in Austrocedrus chilensis forests and inside Nothofagus dombeyi forest gaps. Detailed field assessments of rose cover performed in seven habitat types supported these results: rose cover significantly decreased with increasing tree cover (P < 0.01). Our data revealed that the occurrence of R. rubiginosa is not connected to a certain habitat type, but that it thrives in open patches following habitat disturbance. Our approach is a widely applicable, cost‐free remote sensing method that can serve as a risk assessment tool for alien plant species invasion of habitats. 相似文献
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Although reserves of temperate seminatural grassland require management interventions to prevent succesional change, each intervention affects the populations of sensitive organisms, including insects. Therefore, it appears as a wise bet-hedging strategy to manage reserves in diverse and patchy manners. Using portable light traps, we surveyed the effects of two contrasting management options, mowing and temporary abandonment, applied in a humid grassland reserve in a submountain area of the Czech Republic. Besides of Macrolepidoptera, we also surveyed Microlepidoptera, small moths rarely considered in community studies. Numbers of individiuals and species were similar in the two treatments, but ordionation analyses showed that catches originating from these two treatments differed in species composition, management alone explaining ca 30 per cent of variation both for all moths and if split to Marcolepidoptera and Microlepidoptera. Whereas a majority of macrolepidopteran humid grassland specialists preferred unmown sections or displayed no association with management, microlepidopteran humid grassland specialists contained equal representation of species inclining towards mown and unmown sections. We thus revealed that even mown section may host valuable species; an observation which would not have been detected had we considered Macrolepidoptera only. Our results highlight the necessity of diversified management, including temporary abandonment, to conserve the biodiversity of grassland reserves and grasslands in general. 相似文献