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11.
Mohammed F. Alum Paul A. Shaw Brian C. Sweatman Baljit K. Ubhi John N. Haselden Susan C. Connor 《Metabolomics : Official journal of the Metabolomic Society》2008,4(2):122-127
Nuclear magnetic resonance (NMR)-based metabolic profiling of biofluids and tissues are of key interest to enhance biomarker
discovery for disease, drug efficacy and toxicity studies. Urine and blood plasma/serum are the biofluids of most interest
as they are the most accessible in both clinical and preclinical studies. However, proteinaceous fluids, such as blood serum
or plasma, represent the greatest technical challenge since the chemical shift (δ) and line-width (ν1/2) of internal standards currently used for aqueous NMR samples are greatly affected by protein binding. We have therefore
investigated the suitability of 4,4-dimethyl-4-silapentane-1-ammonium trifluoroacetate (DSA) as a universal internal standard
for biofluids. Proton (1H) NMR spectroscopy was used to determine the effect of serum pH (3, 7.4 and 10) and DSA concentration on the overall lineshape
and position of the trimethylsilyl resonance of DSA. The results were compared to that of 3-(trimethylsilyl)propionic acid
sodium salt (TSP). Both the chemical shift and line-width of the DSA peak were not significantly affected by pH or DSA concentration,
whereas these parameters for TSP showed large variations due to protein binding. Furthermore, the peak area of DSA correlated
linearly with its concentration under all pH conditions, whilst no linear correlation was observed with TSP. Overall, in contrast
to TSP, these results support the use of DSA as an accurate universal internal chemical shift reference and concentration/normalisation
standard for biofluids. In the case of proteinaceous biofluids such as serum, where no current standard is available, this
offers a considerable saving in both operator and spectrometer time. 相似文献
12.
Parker MS Sah R Balasubramaniam A Sallee FR Sweatman T Park EA Parker SL 《Journal of receptor and signal transduction research》2008,28(5):437-451
In conditions precluding activation of G proteins, the binding of agonists to dimers of the neuropeptide Y (NPY) Y2 receptor shows two components of similar size, but differing in affinity. The dimers of all NPY receptors are solubilized as approximately 180-kDa complexes containing one G protein alpha beta gamma trimer. These heteropentamers are stable to excess agonists, chelators, and alkylators. However, dispersion in the weak surfactant cholate releases approximately 300-kDa complexes. These findings indicate that both protomers in the Y2 dimer are associated with G protein heterotrimers, but the extent of interaction depends on affinity for the agonist peptide. The G protein in contact with the first-liganded, higher-affinity protomer should have a stronger interaction with the receptor and a larger probability of activation. 相似文献
13.
No-take reserves protect coral reefs from predatory starfish 总被引:1,自引:0,他引:1
Sweatman H 《Current biology : CB》2008,18(14):R598-R599
The crown-of-thorns starfish, Acanthaster planci, is a predator of corals that is a major management issue on coral reefs [1]. It occurs throughout the Indo–Pacific and shows boom–bust population dynamics with low background densities and intermittent outbreaks. Three waves of population outbreaks have affected Australia's Great Barrier Reef (GBR) since the 1960s. The waves of outbreaks appear to start 15°S [2] and progress southward through the central GBR (Figure 1A), causing major losses of living coral on many reefs across a large area and dwarfing losses from other disturbances such as storms or coral bleaching over the same period [3]. Humans can potentially influence starfish population dynamics by exploiting predators, though evidence to date is circumstantial. Extensive surveys in the GBR Marine Park (GBRMP) show that protection from fishing affects the frequency of outbreaks: the relative frequency of outbreaks on reefs that were open to fishing was 3.75 times higher than that on no-take reefs in the mid-shelf region of the GBR, where most outbreaks occur, and seven times greater on open reefs if all reefs were included. Although exploited fishes are unlikely to prey on starfish directly, trophic cascades could favour invertebrates that prey on juvenile starfish. 相似文献
14.
Rapid increase in fish numbers follows creation of world's largest marine reserve network 总被引:4,自引:0,他引:4
Russ GR Cheal AJ Dolman AM Emslie MJ Evans RD Miller I Sweatman H Williamson DH 《Current biology : CB》2008,18(12):R514-R515
No-take marine reserves (NTMRs) are much advocated as a solution to managing marine ecosystems, protecting exploited species and restoring natural states of biodiversity [1,2]. Increasingly, it is becoming clear that effective marine conservation and management at ecosystem and regional scales requires extensive networks of NTMRs [1,2]. The world's largest network of such reserves was established on Australia's Great Barrier Reef (GBR) in 2004. Closing such a large area to all fishing has been socially and politically controversial, making it imperative that the effectiveness of this new reserve network be assessed. Here we report evidence, first, that the densities of the major target species of the GBR reef line fisheries were significantly higher in the new NTMRs, compared with fished sites, in just two years; and second, that the positive differences were consistent for multiple marine reserves over an unprecedented spatial scale (>1,000 km). 相似文献
15.
Habitat utilization by coral reef fish: implications for specialists vs. generalists in a changing environment 总被引:2,自引:0,他引:2
Wilson SK Burgess SC Cheal AJ Emslie M Fisher R Miller I Polunin NV Sweatman HP 《The Journal of animal ecology》2008,77(2):220-228
1. The impact of environmental disturbance and habitat loss on associated species is expected to be dependent on a species' level of specialization. We examined habitat use and specialization of coral reef fish from the diverse and ecologically important family Pomacentridae, and determined which species are susceptible to declines in coral cover due to disturbance induced by crown-of-thorns seastar (COTS, Acanthaster planci L.). 2. A high proportion of pomacentrid species live in association with live coral as adults (40%) or juveniles (53%). Adults of many species had strong affiliations with branching corals, while juveniles favoured plating growth forms, reflecting the sizes of refuge provided by coral types. 3. Juveniles of species that associated with coral had narrower niche breadths than adult conspecifics, due to associations with specific coral types. The especially high coral association and narrower niche breadth of juveniles suggest that the presence of live coral is crucial for many species during early life history, and that disturbance-induced coral loss may have serious flow-on effects on adult abundance. 4. Microhabitat availability was a poor predictor of fish species abundance. Significant correlations between coverage of coral types and abundance of five adults and two juvenile species were detected; however, these relationships explained <35% and <10% of the variation in abundance of adult and juvenile species, respectively. 5. Niche breadth explained 74% of the variation in species' mean response to coral decline and it is clear that disturbance has a greater impact on resource specialists, suggesting that increasing frequency and intensity of coral loss will cause reef fish communities to become dominated by habitat generalists at the expense of coral-dwelling specialists. 相似文献
16.
S. K. Wilson A. M. Dolman A. J. Cheal M. J. Emslie M. S. Pratchett H. P. A. Sweatman 《Coral reefs (Online)》2009,28(1):3-14
Habitat perturbations play a major role in shaping community structure; however, the elements of disturbance-related habitat
change that affect diversity are not always apparent. This study examined the effects of habitat disturbances on species richness
of coral reef fish assemblages using annual surveys of habitat and 210 fish species from 10 reefs on the Great Barrier Reef
(GBR). Over a period of 11 years, major disturbances, including localised outbreaks of crown-of-thorns sea star (Acanthaster planci), severe storms or coral bleaching, resulted in coral decline of 46–96% in all the 10 reefs. Despite declines in coral cover,
structural complexity of the reef framework was retained on five and species richness of coral reef fishes maintained on nine
of the disturbed reefs. Extensive loss of coral resulted in localised declines of highly specialised coral-dependent species,
but this loss of diversity was more than compensated for by increases in the number of species that feed on the epilithic
algal matrix (EAM). A unimodal relationship between areal coral cover and species richness indicated species richness was
greatest at approximately 20% coral cover declining by 3–4 species (6–8% of average richness) at higher and lower coral cover.
Results revealed that declines in coral cover on reefs may have limited short-term impact on the diversity of coral reef fishes,
though there may be fundamental changes in the community structure of fishes. 相似文献
17.
Martijn F Schenk Jan HG Cordewener Antoine HP America Wendy PC van't Westende Marinus JM Smulders Luud JWJ Gilissen 《BMC plant biology》2009,9(1):24
Background
Bet v 1 is an important cause of hay fever in northern Europe. Bet v 1 isoforms from the European white birch (Betula pendula) have been investigated extensively, but the allergenic potency of other birch species is unknown. The presence of Bet v 1 and closely related PR-10 genes in the genome was established by amplification and sequencing of alleles from eight birch species that represent the four subgenera within the genus Betula. Q-TOF LC-MSE was applied to identify which PR-10/Bet v 1 genes are actually expressed in pollen and to determine the relative abundances of individual isoforms in the pollen proteome. 相似文献18.
19.
C. B. Edwards A. M. Friedlander A. G. Green M. J. Hardt E. Sala H. P. Sweatman I. D. Williams B. Zgliczynski S. A. Sandin J. E. Smith 《Proceedings. Biological sciences / The Royal Society》2014,281(1774)
On coral reefs, herbivorous fishes consume benthic primary producers and regulate competition between fleshy algae and reef-building corals. Many of these species are also important fishery targets, yet little is known about their global status. Using a large-scale synthesis of peer-reviewed and unpublished data, we examine variability in abundance and biomass of herbivorous reef fishes and explore evidence for fishing impacts globally and within regions. We show that biomass is more than twice as high in locations not accessible to fisheries relative to fisheries-accessible locations. Although there are large biogeographic differences in total biomass, the effects of fishing are consistent in nearly all regions. We also show that exposure to fishing alters the structure of the herbivore community by disproportionately reducing biomass of large-bodied functional groups (scraper/excavators, browsers, grazer/detritivores), while increasing biomass and abundance of territorial algal-farming damselfishes (Pomacentridae). The browser functional group that consumes macroalgae and can help to prevent coral–macroalgal phase shifts appears to be most susceptible to fishing. This fishing down the herbivore guild probably alters the effectiveness of these fishes in regulating algal abundance on reefs. Finally, data from remote and unfished locations provide important baselines for setting management and conservation targets for this important group of fishes. 相似文献
20.