| 11. |
- Akhtar, Malik N., et al.
(författare)
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Evaluation of Database Search Programs for Accurate Detection of Neuropeptides in Tandem Mass Spectrometry Experiments
- 2012
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 11:12, s. 6044-6055
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Tidskriftsartikel (refereegranskat)abstract
- Neuropeptide identification in mass spectrometry experiments using database search programs developed for proteins is challenging. Unlike proteins, the detection of the complete sequence using a single spectrum is required to identify neuropeptides or prohormone peptides. This study compared the performance of three open-source programs used to identify proteins, OMSSA, X!Tandem and Crux, to identify prohormone peptides. From a target database of 7850 prohormone peptides, 23550 query spectra were simulated across different scenarios. Crux was the only program that correctly matched all peptides regardless of p-value and at p-value < 1 X 10(-2), 33%, 64%, and >75%, of the 5, 6, and >= 7 amino acid-peptides were detected. Crux also had the best performance in the identification of peptides from chimera spectra and in a variety of missing ion scenarios. OMSSA, X!Tandem and Crux correctly detected 98.9% (99.9%), 93.9% (97.4%) and 88.7% (98.3%) of the peptides at E- or p-value < 1 X 10(-6) (< 1 X 10(-2)), respectively. OMSSA and X! Tandem outperformed the other programs in significance level and computational speed, respectively. A consensus approach is not recommended because some prohormone peptides were only identified by one program.
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| 12. |
- Akhtar, Malik N., et al.
(författare)
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Identification of best indicators of peptide-spectrum match using a permutation resampling approach
- 2014
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Ingår i: Journal of Bioinformatics and Computational Biology. - 0219-7200 .- 1757-6334. ; 12:5, s. 1440001-
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Tidskriftsartikel (refereegranskat)abstract
- Various indicators of observed-theoretical spectrum matches were compared and the resulting statistical significance was characterized using permutation resampling. Novel decoy databases built by resampling the terminal positions of peptide sequences were evaluated to identify the conditions for accurate computation of peptide match significance levels. The methodology was tested on real and manually curated tandem mass spectra from peptides across a wide range of sizes. Spectra match indicators from complementary database search programs were pro filed and optimal indicators were identified. The combination of the optimal indicator and permuted decoy databases improved the calculation of the peptide match significance compared to the approaches currently implemented in the database search programs that rely on distributional assumptions. Permutation tests using p-values obtained from software-dependent matching scores and E-values outperformed permutation tests using all other indicators. The higher overlap in matches between the database search programs when using end permutation compared to existing approaches con firmed the superiority of the end permutation method to identify peptides. The combination of effective match indicators and the end permutation method is recommended for accurate detection of peptides.
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| 13. |
- Rayner, Matt J., et al.
(författare)
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Using miniaturized radiotelemetry to discover the breeding grounds of the endangered New Zealand Storm Petrel Fregetta maoriana
- 2015
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Ingår i: Ibis. - : Wiley. - 0019-1019. ; 157:4, s. 754-766
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Tidskriftsartikel (refereegranskat)abstract
- Identification of breeding sites remains a critical step in species conservation, particularly in procellariiform seabirds whose threat status is of global concern. We designed and conducted an integrative radiotelemetry approach to uncover the breeding grounds of the critically endangered New Zealand Storm Petrel Fregetta maoriana (NZSP), a species considered extinct before its rediscovery in 2003. Solar-powered automated radio receivers and hand-held telemetry were used to detect the presence of birds on three island groups in the Hauraki Gulf near Auckland, New Zealand. At least 11 NZSP captured and radiotagged at sea were detected at night near Te Hauturu-o-Toi/Little Barrier Island with the detection of an incubating bird leading to the discovery of the first known breeding site for this species. In total, four NZSP breeding burrows were detected under mature forest canopy and three adult NZSP and two NZSP chicks were ringed. Telemetry data indicated NZSP showed strong moonlight avoidance behaviour over the breeding site, had incubation shifts of approximately 5days and had a breeding season extending from February to June/July, a different season from other Procellariiformes in the region. Radiotelemetry, in combination with rigorously collected field data on species distribution, offers a valuable technique for locating breeding grounds of procellariiform seabirds and gaining insights into breeding biology while minimizing disturbance to sensitive species or damage to fragile habitat. Our study suggests an avenue for other breeding ground searches in one of the most threatened avian Orders, and highlights the general need for information on the location of breeding sites and understanding the breeding biology in data-deficient birds.
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