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101.
Fisheries bycatch is a key threat to cetacean species globally. Managing the impact requires an understanding of the conditions under which animals are caught and the sections of the population affected. We used observer data collected on an albacore tuna gillnet fishery in the northeast Atlantic, to assess operational and environmental factors contributing to bycatch of common and striped dolphins, using generalised linear models and model averaging. Life history demographics of the captured animals were also investigated. In both species, young males dominated the catch. The age ratio of common dolphins was significantly different from that estimated for the population in the region, based on life tables (G = 17.1, d.f. = 2, p = 0.002). Skewed age and sex ratios may reflect varying vulnerability to capture, through differences in behaviour or segregation in populations. Adult females constituted the second largest portion of the bycatch for both species, with potential consequences for population sustainability. Depth was the most important parameter influencing bycatch of both species and reflected what is known about common and striped dolphin habitat use in the region as the probability of catching common dolphins decreased, and striped dolphins increased, with increasing depth. Striped dolphin capture was similarly influenced by the extent to which operations were conducted in daylight, with the probability of capture increasing with increased operations in the pre-sunset and post-sunrise period, potentially driven by increased ability of observers to record animals during daylight operations, or by diurnal movements increasing contact with the fishery. Effort, based on net length and soak time, had little influence on the probability of capturing either species. Our results illustrate the importance of assessing the demographic of the animals captured during observer programmes and, perhaps more importantly, suggest that effort restrictions alone may not be sufficient to eradicate bycatch in areas where driftnets and small cetaceans co-occur. 相似文献
102.
Joni A. Miranda Natasha Yates Ariana Agustines Nonie P. Enolva Jessica Labaja Christine Legaspi Emer McCoy Alessandro Ponzo Sally Snow Gonzalo Araujo 《Journal of fish biology》2021,98(3):881-885
Little is known about the reproductive ecology of the whale shark Rhincodon typus. On 15 March 2020, a free-swimming neonate whale shark was found in the shallow, coastal waters of Donsol, Philippines. The total length of the male shark was 60 cm, falling within the species known size-at-birth. This is the third occurrence of neonatal whale sharks reported in the area, and coupled with the occurrence of juveniles and adults, and anecdotal mating and precopulatory behaviour reported herein, the importance of the site for this endangered species is highlighted. 相似文献
103.
Enzymes and receptors of prostaglandin pathways with arachidonic acid-derived versus eicosapentaenoic acid-derived substrates and products 总被引:4,自引:0,他引:4
Wada M DeLong CJ Hong YH Rieke CJ Song I Sidhu RS Yuan C Warnock M Schmaier AH Yokoyama C Smyth EM Wilson SJ FitzGerald GA Garavito RM Sui de X Regan JW Smith WL 《The Journal of biological chemistry》2007,282(31):22254-22266
Dietary fish oil containing omega 3 highly unsaturated fatty acids has cardioprotective and anti-inflammatory effects. Prostaglandins (PGs) and thromboxanes are produced in vivo both from the omega 6 fatty acid arachidonic acid (AA) and the omega 3 fatty acid eicosapentaenoic acid (EPA). Certain beneficial effects of fish oil may result from altered PG metabolism resulting from increases in the EPA/AA ratios of precursor phospholipids. Here we report in vitro specificities of prostanoid enzymes and receptors toward EPA-derived, 3-series versus AA-derived, 2-series prostanoid substrates and products. The largest difference was seen with PG endoperoxide H synthase (PGHS)-1. Under optimal conditions purified PGHS-1 oxygenates EPA with only 10% of the efficiency of AA, and EPA significantly inhibits AA oxygenation by PGHS-1. Two- to 3-fold higher activities or potencies with 2-series versus 3-series compounds were observed with PGHS-2, PGD synthases, microsomal PGE synthase-1 and EP1, EP2, EP3, and FP receptors. Our most surprising observation was that AA oxygenation by PGHS-2 is only modestly inhibited by EPA (i.e. PGHS-2 exhibits a marked preference for AA when EPA and AA are tested together). Also unexpectedly, TxA(3) is about equipotent to TxA(2) at the TP alpha receptor. Our biochemical data predict that increasing phospholipid EPA/AA ratios in cells would dampen prostanoid signaling with the largest effects being on PGHS-1 pathways involving PGD, PGE, and PGF. Production of 2-series prostanoids from AA by PGHS-2 would be expected to decrease in proportion to the compensatory decrease in the AA content of phospholipids that would result from increased incorporation of omega 3 fatty acids such as EPA. 相似文献
104.
Michaël C Fontaine Stuart JE Baird Sylvain Piry Nicolas Ray Krystal A Tolley Sarah Duke Alexei Birkun Jr Marisa Ferreira Thierry Jauniaux Ángela Llavona Bayram Öztürk Ayaka A Öztürk Vincent Ridoux Emer Rogan Marina Sequeira Ursula Siebert Gísli A Vikingsson Jean-Marie Bouquegneau Johan R Michaux 《BMC biology》2007,5(1):1-16
Background
Understanding the role of seascape in shaping genetic and demographic population structure is highly challenging for marine pelagic species such as cetaceans for which there is generally little evidence of what could effectively restrict their dispersal. In the present work, we applied a combination of recent individual-based landscape genetic approaches to investigate the population genetic structure of a highly mobile extensive range cetacean, the harbour porpoise in the eastern North Atlantic, with regards to oceanographic characteristics that could constrain its dispersal.Results
Analyses of 10 microsatellite loci for 752 individuals revealed that most of the sampled range in the eastern North Atlantic behaves as a 'continuous' population that widely extends over thousands of kilometres with significant isolation by distance (IBD). However, strong barriers to gene flow were detected in the south-eastern part of the range. These barriers coincided with profound changes in environmental characteristics and isolated, on a relatively small scale, porpoises from Iberian waters and on a larger scale porpoises from the Black Sea.Conclusion
The presence of these barriers to gene flow that coincide with profound changes in oceanographic features, together with the spatial variation in IBD strength, provide for the first time strong evidence that physical processes have a major impact on the demographic and genetic structure of a cetacean. This genetic pattern further suggests habitat-related fragmentation of the porpoise range that is likely to intensify with predicted surface ocean warming. 相似文献105.
Phillip J. Dugger Pedro G. Blendinger Katrin Bhning‐Gaese Lackson Chama Marta Correia D. Matthias Dehling Carine Emer Nina Farwig Evan C. Fricke Mauro Galetti Daniel García Ingo Grass Ruben Heleno Fbio A. F. Jacomassa Suelen Moraes Catherine Moran Marcia C. Muoz Eike Lena Neuschulz Larissa Nowak Augusto Piratelli Marco A. Pizo Marta Quitin Haldre S. Rogers Romn A. Ruggera Francisco Saavedra Mariano S. Snchez Rocío Snchez Vinicio Santilln Dana G. Schabo Fernanda Ribeiro da Silva Srgio Timteo Anna Traveset Maximilian G. R. Vollstdt Matthias Schleuning 《Global Ecology and Biogeography》2019,28(2):i-i
106.
Heidi Colleran Grazyna Jasienska Ilona Nenko Andrzej Galbarczyk Ruth Mace 《Proceedings. Biological sciences / The Royal Society》2015,282(1806)
In the course of demographic transitions (DTs), two large-scale trends become
apparent: (i) the broadly positive association between wealth, status and
fertility tends to reverse, and (ii) wealth inequalities increase and then
temporarily decrease. We argue that these two broad patterns are linked, through
a diversification of reproductive strategies that subsequently converge as
populations consume more, become less self-sufficient and increasingly depend on
education as a route to socio-economic status. We examine these links using data
from 22 mid-transition communities in rural Poland. We identify changing
relationships between fertility and multiple measures of wealth, status and
inequality. Wealth and status generally have opposing effects on fertility, but
these associations vary by community. Where farming remains a viable livelihood,
reproductive strategies typical of both pre- and post-DT populations coexist.
Fertility is lower and less variable in communities with lower wealth
inequality, and macro-level patterns in inequality are generally reproduced at
the community level. Our results provide a detailed insight into the changing
dynamics of wealth, status and inequality that accompany DTs at the community
level where peoples'' social and economic interactions typically take
place. We find no evidence to suggest that women with the most educational
capital gain wealth advantages from reducing fertility, nor that higher
educational capital delays the onset of childbearing in this population. Rather,
these patterns reflect changing reproductive preferences during a period of
profound economic and social change, with implications for our understanding of
reproductive and socio-economic inequalities in transitioning populations. 相似文献
107.
Sayani Dasgupta Michael A. Fishman Hana Mahallati Leandro M. Castro Alexandre K. Tashima Emer S. Ferro Lloyd D. Fricker 《PloS one》2015,10(12)
Huntington’s disease is the result of a long polyglutamine tract in the gene encoding huntingtin protein, which in turn causes a large number of cellular changes and ultimately results in neurodegeneration of striatal neurons. Although many theories have been proposed, the precise mechanism by which the polyglutamine expansion causes cellular changes is not certain. Some evidence supports the hypothesis that the long polyglutamine tract inhibits the proteasome, a multiprotein complex involved in protein degradation. However, other studies report normal proteasome function in cells expressing long polyglutamine tracts. The controversy may be due to the methods used to examine proteasome activity in each of the previous studies. In the present study, we measured proteasome function by examining levels of endogenous peptides that are products of proteasome cleavage. Peptide levels were compared among mouse striatal cell lines expressing either 7 glutamines (STHdh
Q7/Q7) or 111 glutamines in the huntingtin protein, either heterozygous (STHdh
Q7/Q111) or homozygous (STHdh
Q111/Q111). Both of the cell lines expressing huntingtin with 111 glutamines showed a large reduction in nearly all of the peptides detected in the cells, relative to levels of these peptides in cells homozygous for 7 glutamines. Treatment of STHdh
Q7/Q7 cells with proteasome inhibitors epoxomicin or bortezomib also caused a large reduction in most of these peptides, suggesting that they are products of proteasome-mediated cleavage of cellular proteins. Taken together, these results support the hypothesis that proteasome function is impaired by the expression of huntingtin protein containing long polyglutamine tracts. 相似文献
108.
Jessica E. Potts Laura J. Gray Emer M. Brady Kamlesh Khunti Melanie J. Davies Danielle H. Bodicoat 《PloS one》2015,10(6)
Aims
To determine the effects of glucagon-like peptide-1 receptor agonists compared with placebo and other anti-diabetic agents on weight loss in overweight or obese patients with type 2 diabetes mellitus.Methods
Electronic searches were conducted for randomised controlled trials that compared a glucagon-like peptide-1 receptor agonist therapy at a clinically relevant dose with a comparator treatment (other type 2 diabetes treatment or placebo) in adults with type 2 diabetes and a mean body mass index ≥ 25kg/m2. Pair-wise meta-analyses and mixed treatment comparisons were conducted to examine the difference in weight change at six months between the glucagon-like peptide-1 receptor agonists and each comparator.Results
In the mixed treatment comparison (27 trials), the glucagon-like peptide-1 receptor agonists were the most successful in terms of weight loss; exenatide 2mg/week: -1.62kg (95% CrI: -2.95kg, -0.30kg), exenatide 20μg: -1.37kg (95% CI: -222kg, -0.52kg), liraglutide 1.2mg: -1.01kg (95%CrI: -2.41kg, 0.38kg) and liraglutide 1.8mg: -1.51 kg (95% CI: -2.67kg, -0.37kg) compared with placebo. There were no differences between the GLP-1 receptor agonists in terms of weight loss.Conclusions
This review provides evidence that glucagon-like peptide-1 receptor agonist therapies are associated with weight loss in overweight or obese patients with type 2 diabetes with no difference in weight loss seen between the different types of GLP-1 receptor agonists assessed. 相似文献109.
Peptides have been proposed to function in intracellular signaling within the cytosol. Although cytosolic peptides are considered to be highly unstable, a large number of peptides have been detected in mouse brain and other biological samples. In the present study, we evaluated the peptidome of three diverse cell lines: SH-SY5Y, MCF7, and HEK293 cells. A comparison of the peptidomes revealed considerable overlap in the identity of the peptides found in each cell line. The majority of the observed peptides are not derived from the most abundant or least stable proteins in the cell, and approximately half of the cellular peptides correspond to the N- or C- termini of the precursor proteins. Cleavage site analysis revealed a preference for hydrophobic residues in the P1 position. Quantitative peptidomic analysis indicated that the levels of most cellular peptides are not altered in response to elevated intracellular calcium, suggesting that calpain is not responsible for their production. The similarity of the peptidomes of the three cell lines and the lack of correlation with the predicted cellular degradome implies the selective formation or retention of these peptides, consistent with the hypothesis that they are functional in the cells. 相似文献
110.