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排序方式: 共有180条查询结果,搜索用时 281 毫秒
81.
S Avidon SM Marr TA Bellingan KJ Esler OLF Weyl 《African Journal of Aquatic Science》2018,43(3):313-318
We evaluated the impact of non-native rainbow trout Oncorhynchus mykiss on a population of endemic Cedarberg ghost frog Heleophryne depressa in the upper Krom River (Olifants-Doring River Catchment, Cape Fold Ecoregion). We compared H. depressa abundance (using kick-sampling and underwater video analysis) and environmental conditions between sites above and below a waterfall that marks the upper distribution limit of O. mykiss. Heleophryne depressa abundance was significantly greater above the waterfall than that below it, and, because there was no significant difference in measured environmental variables, O. mykiss presence is identified as the most likely explanation for the observed decrease in H. depressa abundance. 相似文献
82.
Electrophoretic surveys of 13 enzyme-coding loci distinguished unambiguously five morphologically defined species of Porites and two species of Goniopora. Each species was identifiable solely by unique, qualitative banding patterns at 1–6 loci. Genetic distances give preliminary estimates that these Porites species diverged from common ancestors 8–22 Ma during the Miocene, and that the two Goniopora species diverged about 3.5 Ma in the Pliocene, assuming Porites evolved from Goniopora 55 million years ago (Ma).
Correspondence to: R. L. Garthwaite 相似文献
83.
M. Perez B. Li A. Tillier A. Cruaud G. Veron 《Journal of Zoological Systematics and Evolutionary Research》2006,44(3):251-259
The relationships within the mongooses (Herpestidae) have been recently reconsidered on the basis of molecular data. However, these studies failed to completely resolve the relationships within the subfamily Herpestinae. Moreover, the species of the genus Bdeogale have not been included in previous studies. Three genes were sequenced, Cytochrome b, ND2 and Transthyretin intron I, for 20 species of Herpestidae. The results show that the Herpestidae form two clades, corresponding to the traditional Herpestinae and Mungotinae, but with Cynictis included in the former rather than the latter. Within the Herpestinae, the genus Herpestes is not monophyletic. A newly proposed clade groups Bdeogale, Cynictis, Ichneumia and Rynchogale. Some morphological and karyological characters were mapped on the trees so as to characterize the newly defined molecular groups. 相似文献
84.
Systematic status and biogeography of the Javan and small Indian mongooses (Herpestidae, Carnivora) 总被引:2,自引:0,他引:2
Geraldine Veron Marie-Lilith Patou Geraldine Pothet Daniel Simberloff & Andrew P. Jennings 《Zoologica scripta》2007,36(1):1-10
The Javan and small Indian mongooses, ranging from the Middle East to South-east Asia, are considered as two species or as a single species, varying in size and colour from west to east. In order to clarify their systematic status and to define the limits of their ranges, Cytochrome b sequences were obtained from 27 specimens, and localities of 392 specimens from museum collections were determined. The phylogenetic analyses revealed that the Javan and Small Indian mongooses grouped in two separate clades with their range limits located in Myanmar. The Javan mongoose is in fact closer to the grey mongoose than to the small Indian mongoose. 相似文献
85.
Simon Veron Caterina Penone Philippe Clergeau Gabriel C. Costa Brunno F. Oliveira Vinícius A. São‐Pedro Sandrine Pavoine 《Ecology and evolution》2016,6(23):8502-8514
There is an increasing interest in measuring loss of phylogenetic diversity and evolutionary distinctiveness which together depict the evolutionary history of conservation interest. Those losses are assessed through the evolutionary relationships between species and species threat status or extinction probabilities. Yet, available information is not always sufficient to quantify the threat status of species that are then classified as data deficient. Data‐deficient species are a crucial issue as they cause incomplete assessments of the loss of phylogenetic diversity and evolutionary distinctiveness. We aimed to explore the potential bias caused by data‐deficient species in estimating four widely used indices: HEDGE, EDGE, PDloss, and Expected PDloss. Second, we tested four different widely applicable and multitaxa imputation methods and their potential to minimize the bias for those four indices. Two methods are based on a best‐ vs. worst‐case extinction scenarios, one is based on the frequency distribution of threat status within a taxonomic group and one is based on correlates of extinction risks. We showed that data‐deficient species led to important bias in predictions of evolutionary history loss (especially high underestimation when they were removed). This issue was particularly important when data‐deficient species tended to be clustered in the tree of life. The imputation method based on correlates of extinction risks, especially geographic range size, had the best performance and enabled us to improve risk assessments. Solving threat status of DD species can fundamentally change our understanding of loss of phylogenetic diversity. We found that this loss could be substantially higher than previously found in amphibians, squamate reptiles, and carnivores. We also identified species that are of high priority for the conservation of evolutionary distinctiveness. 相似文献
86.
A J Harwood N A Hopper M N Simon S Bouzid M Veron J G Williams 《Developmental biology》1992,149(1):90-99
The cAMP-dependent protein kinase (PKA) holoenzyme of Dictyostelium comprises a single regulatory (R) and catalytic (C) subunit, and both proteins increase in concentration during cellular aggregation. In order to determine the role of the kinase, we have constructed mutants of the R subunit that are defective in cAMP binding, in inhibition of the C subunit, or in both functions. Analysis of these mutants suggests that overexpression of the unmutated R subunit, which is known to block development, occurs by direct inactivation of the C subunit rather than by an effect on intracellular cAMP levels. Cells with an inactive C subunit (PKA- cells) are defective in cAMP relay, the production of cAMP in response to extracellular cAMP stimulation. This presumably accounts for their inability to undertake aggregation. When mixed with wild-type cells, PKA- cells migrate toward the signalling centre but remain confined to the periphery of the tight aggregate and are lost from the back of the migratory slug. This suggests that PKA may be required during the late, multicellular stages of development. Consistent with this, we find that a number of postaggregative genes are not expressed in PKA- cells, even when they are allowed to synergise with normal cells. 相似文献
87.
The Olifants River, a tributary of the Limpopo River system, is one of the most polluted rivers in South Africa. In May 2011 the concentrations of metals in fish muscle tissue from two impoundments, Loskop and Flag Boshielo dams, on the Olifants River were measured and a human health risk assessment conducted to investigate whether it was safe to consume Labeo rosae from these impoundments. Labeo rosae is one of the most common pan fish in these impoundments and is readily available to rural communities. Metals are accumulating in the muscle tissue of L. rosae even although the fish populations appear to be healthy. At Loskop Dam all L. rosae analysed exceeded the recommended hazard quotient (HQ) of 1 for antimony, and less than 50% exceeded that for lead. At Flag Boshielo Dam, the recommended HQ was exceeded for lead in less than 50% of L. rosae analysed, and more than 50% exceeded that for antimony. The weekly consumption of 150?g of L. rosae muscle tissue from these impoundments may pose an unacceptable health risk to rural communities. 相似文献
88.
Priya Chatterji Patrick A Williams Kelly A Whelan Fernando C Samper Sarah F Andres Lauren A Simon Louis R Parham Rei Mizuno Emma T Lundsmith David SM Lee Shun Liang HR
Sagara Wijeratne Stefanie Marti Lillian Chau Veronique Giroux Benjamin J Wilkins Gary D Wu Premal Shah Gian G Tartaglia Kathryn E Hamilton 《EMBO reports》2021,22(8)
Correction to: EMBO Reports (2019) 20: e47074. DOI 10.15252/embr.201847074 | Published online 6 May 2019The authors noticed that the control and disease labels had been inverted in their data analysis resulting in publication of incorrect data in Figure 1C. The corrected figure is displayed below. This change affects the conclusions as detailed below. The authors apologize for this error and any confusion it may have caused.In the legend of 1C, change from, “Differential gene expression analysis of pediatric ileal CD patient samples (n = 180) shows increased (> 4‐fold) IMP1 expression as compared to non‐inflammatory bowel disease (IBD) pediatric samples (n = 43)”.Open in a separate windowFigure 1CCorrected Open in a separate windowFigure 1COriginal To, "Differential gene expression analysis of pediatric ileal CD patient samples (n = 180) shows decreased (> 4‐fold) IMP1 expression as compared to non‐inflammatory bowel disease (IBD) pediatric samples (n = 43)”.In abstract, change from, “Here, we report increased IMP1 expression in patients with Crohn''s disease and ulcerative colitis”.To, “Here, we report increased IMP1 expression in adult patients with Crohn''s disease and ulcerative colitis”.In results, change from, “Consistent with these findings, analysis of published the Pediatric RISK Stratification Study (RISK) cohort of RNA‐sequencing data 38 from pediatric patients with Crohn''s disease (CD) patients revealed that IMP1 is upregulated significantly compared to control patients and that this effect is specific to IMP1 (i.e., other distinct isoforms, IMP2 and IMP3, are not changed; Fig 1C)”.To, “Contrary to our findings in colon tissue from adults, analysis of published RNA‐sequencing data from the Pediatric RISK Stratification Study (RISK) cohort of ileal tissue from children with Crohn’s disease (CD) 38 revealed that IMP1 is downregulated significantly compared to control patients in the RISK cohort and that this effect is specific to IMP1 (i.e., other distinct isoforms, IMP2 and IMP3, are not changed; Fig 1C)”.In discussion, change from, “Indeed, we report that IMP1 is upregulated in patients with Crohn''s disease and ulcerative colitis and that mice with Imp1 loss exhibit enhanced repair following DSS‐mediated damage”.To “Indeed, we report that IMP1 is upregulated in adult patients with Crohn''s disease and ulcerative colitis and that mice with Imp1 loss exhibit enhanced repair following DSS‐mediated damage”. 相似文献
89.
90.
In this study we reconstruct pollutant lead transport and input into the Caribbean basin in relation to the meteorological changes and past industrial activities. These reconstructions are based on the geochemical data obtained from massive corals collected in 1998 in Mona Island. Lead concentration profile mimics the general atmospheric lead trend obtained from the previous investigations on ice cores, carbonate skeletons and in sediments from the North Atlantic. This similarity corroborates the significance of anthropogenic impact on all reservoirs of the North Atlantic as associated with the proliferation of the automobile and use of leaded gasoline during the twentieth century. Our high-resolution record reveals a 2–4 years shift between the maximum pollutant lead input to Mona Island and leaded gasoline consumption peaks in North America, suggesting a possible longer secondary oceanic transport of US lead within the Subtropical North Atlantic Gyre system. A striking relationship is found between lead isotopic imprints and the winter North Atlantic oscillation (NAO) index for two specific periods (1914–1929 and 1965–1997). These periods are characterized by distinct isotopic signatures from the main pollutant lead emitter to the North Atlantic troposphere, North America and Western Europe. This involves a noteworthy influence of the NAO on pollutant input and distribution in the North Atlantic that strengthens the usefulness of lead isotopes as tracers of paleo-atmospheric circulation and changes in marine circulation pathways. 相似文献