670 research outputs found
Evolution of feeding specialization in Tanganyikan scale-eating cichlids: a molecular phylogenetic approach
<p>Abstract</p> <p>Background</p> <p>Cichlid fishes in Lake Tanganyika exhibit remarkable diversity in their feeding habits. Among them, seven species in the genus <it>Perissodus </it>are known for their unique feeding habit of scale eating with specialized feeding morphology and behaviour. Although the origin of the scale-eating habit has long been questioned, its evolutionary process is still unknown. In the present study, we conducted interspecific phylogenetic analyses for all nine known species in the tribe Perissodini (seven <it>Perissodus </it>and two <it>Haplotaxodon </it>species) using amplified fragment length polymorphism (AFLP) analyses of the nuclear DNA. On the basis of the resultant phylogenetic frameworks, the evolution of their feeding habits was traced using data from analyses of stomach contents, habitat depths, and observations of oral jaw tooth morphology.</p> <p>Results</p> <p>AFLP analyses resolved the phylogenetic relationships of the Perissodini, strongly supporting monophyly for each species. The character reconstruction of feeding ecology based on the AFLP tree suggested that scale eating evolved from general carnivorous feeding to highly specialized scale eating. Furthermore, scale eating is suggested to have evolved in deepwater habitats in the lake. Oral jaw tooth shape was also estimated to have diverged in step with specialization for scale eating.</p> <p>Conclusion</p> <p>The present evolutionary analyses of feeding ecology and morphology based on the obtained phylogenetic tree demonstrate for the first time the evolutionary process leading from generalised to highly specialized scale eating, with diversification in feeding morphology and behaviour among species.</p
Neoirietriol
The title compound {systematic name: (1R,4S,4aS,7R,8aR)-4-bromo-7-[(1S,3R)-3-bromo-1,2,2-trimethylcyclopentyl]-1,4a-dimethyldecahydronaphthalene-1,7,8a-triol}, C20H34Br2O3, is a neoirieane-type bromoditerpenoid isolated from Laurencia yonaguniensis Masuda et Abe, species inedita. The absolute stereochemistry was established as (1S,4R,5R,7R,10S,11S,14R). The structure displays inter- and intramolecular O—H⋯O hydrogen bonding
Anthropogenic contributions to slow warming over 1998-2012
The observed global mean surface temperature increase from 1998 to 2012 was
slower than that since 1951. The relative contributions of all relevant factors
including climate forcers, however, have not been comprehensively analyzed.
Using a reduced-complexity climate model and an observationally constrained
statistical model, we find that La Nina cooling and a descending solar cycle
contributed approximately 50% and 26% of the total warming slowdown during
1998-2012 compared to 1951-2012. Furthermore, reduced ozone-depleting
substances and methane accounted for roughly a quarter of the total warming
slowdown, which can be explained by changes in atmospheric concentrations. We
identify that human factors played an important role in slowing global warming
during 1998-2012, shedding light on the evidence for controlling global warming
by reducing greenhouse gas emissions.Comment: 55 pages, 26 figures, 4 table
Genetic and Morphological Evidence Implies Existence of Two Sympatric Species in Cyathopharynx furcifer
Effects of safflower seed extract on arterial stiffness
Safflower seed extract (SSE) contains characteristic polyphenols and serotonin derivatives (N-( p-coumaroyl) serotonin and N-feruloylserotonin), which are reported to inhibit oxidation of low-density lipoprotein (LDL), formation of atherosclerotic plaques, and improve arterial stiffness as assessed by pulse wave analysis in animal models. The effects of long-term supplementation with SSE on arterial stiffness in human subjects were evaluated. This doubleblind, placebo-controlled study was conducted in 77 males (35–65 years) and 15 postmenopausal females (55–65 years) with high-normal blood pressure or mild hypertension who were not undergoing treatment. Subjects received SSE (70 mg/day as serotonin derivatives) or placebo for 12 weeks, and pulse wave measurements, ie, second derivative of photoplethysmogram (SDPTG), augmentation index, and brachial-ankle pulse wave velocity (baPWV) were conducted at baseline, and at weeks 4, 8, and 12. Vascular age estimated by SDPTG aging index improved in the SSE-supplemented group when compared with the placebo group at four (P = 0.0368) and 12 weeks (P = 0.0927). The trend of augmentation index reduction (P = 0.072 versus baseline) was observed in the SSE-supplemented group, but reduction of baPWV by SSE supplementation was not observed. The SSE-supplemented group also showed a trend towards a lower malondialdehyde-modified-LDL autoantibody titer at 12 weeks from baseline. These results suggest long-term ingestion of SSE in humans could help to improve arterial stiffness
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