排序方式: 共有113条查询结果,搜索用时 15 毫秒
11.
E. Fernando Cagua Jesse E. M. Cochran Christoph A. Rohner Clare E. M. Prebble Tane H. Sinclair-Taylor Simon J. Pierce Michael L. Berumen 《Biology letters》2015,11(4)
Although whale sharks (Rhincodon typus) have been documented to move thousands of kilometres, they are most frequently observed at a few predictable seasonal aggregation sites. The absence of sharks at the surface during visual surveys has led to the assumption that sharks disperse to places unknown during the long ‘off-seasons’ at most of these locations. Here we compare 2 years of R. typus visual sighting records from Mafia Island in Tanzania to concurrent acoustic telemetry of tagged individuals. Sightings revealed a clear seasonal pattern with a peak between October and February and no sharks observed at other times. By contrast, acoustic telemetry demonstrated year-round residency of R. typus. The sharks use a different habitat in the off-season, swimming deeper and further away from shore, presumably in response to prey distributions. This behavioural change reduces the sharks'' visibility, giving the false impression that they have left the area. We demonstrate, for the first time to our knowledge, year-round residency of unprovisioned, individual R. typus at an aggregation site, and highlight the importance of using multiple techniques to study the movement ecology of marine megafauna. 相似文献
12.
Eira Valeria Barrón Edgar Roman-Bassaure Ana Laura Sánchez-Sandoval Ana María Espinosa Mariano Guardado-Estrada Ingrid Medina Eligia Juárez Ana Alfaro Miriam Bermúdez Rubén Zamora Carlos García-Ruiz Juan Carlos Gomora Susana Kofman E. Martha Pérez-Armendariz Jaime Berumen 《PloS one》2015,10(9)
The cyclin-dependent kinase inhibitor 3 (CDKN3) gene, involved in mitosis, is upregulated in cervical cancer (CC). We investigated CDKN3 mRNA as a survival biomarker and potential therapeutic target for CC. CDKN3 mRNA was measured in 134 CC and 25 controls by quantitative PCR. A 5-year survival study was conducted in 121 of these CC patients. Furthermore, CDKN3-specific siRNAs were used to investigate whether CDKN3 is involved in proliferation, migration, and invasion in CC-derived cell lines (SiHa, CaSki, HeLa). CDKN3 mRNA was on average 6.4-fold higher in tumors than in controls (p = 8 x 10−6, Mann-Whitney). A total of 68.2% of CC patients over expressing CDKN3 gene (fold change ≥ 17) died within two years of diagnosis, independent of the clinical stage and HPV type (Hazard Ratio = 5.0, 95% CI: 2.5–10, p = 3.3 x 10−6, Cox proportional-hazards regression). In contrast, only 19.2% of the patients with lower CDKN3 expression died in the same period. In vitro inactivation of CDKN3 decreased cell proliferation on average 67%, although it had no effect on cell migration and invasion. CDKN3 mRNA may be a good survival biomarker and potential therapeutic target in CC. 相似文献
13.
14.
15.
A new scleractinian coral species, Cyphastrea
kausti
sp. n., is described from 13 specimens from the Red Sea. It is characterised by the presence of eight primary septa, unlike the other species of the genus, which have six, ten or 12 primary septa. The new species has morphological affinities with Cyphastrea
microphthalma, from which it can be distinguished by the lower number of septa (on average eight instead of ten), and smaller calices and corallites. This species was observed in the northern and central Red Sea and appears to be absent from the southern Red Sea. 相似文献
16.
M. L. Berumen H. J. Walsh N. Raventos S. Planes G. P. Jones V. Starczak S. R. Thorrold 《Coral reefs (Online)》2010,29(4):883-891
Natural geochemical signatures in calcified structures are commonly employed to retrospectively estimate dispersal pathways
of larval fish and invertebrates. However, the accuracy of the approach is generally untested due to the absence of individuals
with known dispersal histories. We used genetic parentage analysis (genotyping) to divide 110 new recruits of the orange clownfish,
Amphiprion percula, from Kimbe Island, Papua New Guinea, into two groups: “self-recruiters” spawned by parents on Kimbe Island and “immigrants”
that had dispersed from distant reefs (>10 km away). Analysis of daily increments in sagittal otoliths found no significant
difference in PLDs or otolith growth rates between self-recruiting and immigrant larvae. We also quantified otolith Sr/Ca
and Ba/Ca ratios during the larval phase using laser ablation inductively coupled plasma mass spectrometry. Again, we found
no significant differences in larval profiles of either element between self-recruits and immigrants. Our results highlight
the need for caution when interpreting otolith dispersal histories based on natural geochemical tags in the absence of water
chemistry data or known-origin larvae with which to test the discriminatory ability of natural tags. 相似文献
17.
In the absence of detailed assessments of extinction risk, ecological specialisation is often used as a proxy of vulnerability to environmental disturbances and extinction risk. Numerous indices can be used to estimate specialisation; however, the utility of these different indices to predict vulnerability to future environmental change is unknown. Here we compare the performance of specialisation indices using coral‐feeding butterflyfishes as a model group. Our aims were to 1) quantify the dietary preferences of three butterflyfish species across habitats with differing levels of resource availability; 2) investigate how estimates of dietary specialisation vary with the use of different specialisation indices; 3) determine which specialisation indices best inform predictions of vulnerability to environmental change; and 4) assess the utility of resource selection functions to inform predictions of vulnerability to environmental change. The relative level of dietary specialisation estimated for all three species varied when different specialisation indices were used, indicating that the choice of index can have a considerable impact upon estimates of specialisation. Specialisation indices that do not consider resource abundance may fail to distinguish species that primarily use common resources from species that actively target resources disproportionately more than they are available. Resource selection functions provided the greatest insights into the potential response of species to changes in resource availability. Examination of resource selection functions, in addition to specialisation indices, indicated that Chaetodon trifascialis was the most specialised feeder, with highly conserved dietary preferences across all sites, suggesting that this species is highly vulnerable to the impacts of climate‐induced coral loss on reefs. Our results indicate that vulnerability assessments based on some specialisation indices may be misleading and the best estimates of dietary specialisation will be provided by indices which incorporate resource availability measures, as well as assessing responses of species to changes in resource availability. 相似文献
18.
Many species demonstrate variation in life history attributes in response to gradients in environmental conditions. For fishes,
major drivers of life history variation are changes in temperature and food availability. This study examined large-scale
variation in the demography of four species of butterflyfishes (Chaetodon
citrinellus, Chaetodon lunulatus, Chaetodon melannotus, and Chaetodon trifascialis) between two locations on Australia’s Great Barrier Reef (Lizard Island and One Tree Island, separated by approximately 1,200 km).
Variation in age-based demographic parameters was assessed using the re-parameterised von Bertalanffy growth function. All
species displayed measurable differences in body size between locations, with individuals achieving a larger adult size at
the higher latitude site (One Tree Island) for three of the four species examined. Resources and abundances of the study species
were also measured, revealing some significant differences between locations. For example, for C. trifascialis, there was no difference in its preferred resource or in abundance between locations, yet it achieved a larger body size
at the higher latitude location, suggesting a response to temperature. For some species, resources and abundances did vary
between locations, limiting the ability to distinguish between a demographic response to temperature as opposed to a response
to food or competition. Future studies of life histories and demographics at large spatial scales will need to consider the
potentially confounding roles of temperature, resource usage and availability, and abundance/competition to disentangle the
effects of these environmental variables. 相似文献
19.
When biogeographical provinces collide: hybridization of reef fishes at the crossroads of marine biogeographical provinces in the Arabian Sea
下载免费PDF全文
![点击此处可从《Journal of Biogeography》网站下载免费的PDF全文](/ch/ext_images/free.gif)
20.