Project description:Seafood fraud has become a global emerging issue, threatening food security and safety. Adulteration, substitution, dilution, and incorrect labeling of seafood products are fraudulent practices that violate consumer safety. In this context, developing sensitive, robust, and high-throughput molecular tools for food and feed authentication is becoming crucial for regulatory purposes. Analytical approaches such as proteomics mass spectrometry have shown promise in detecting incorrectly labeled products. For the application of these tools, genome information is crucial, but currently, for marine species of commercial importance, such information is unavailable. However, when combining proteomic analysis with spectra library matching, commercially important fish species were successfully identified, differentiated, and quantified in pure muscle samples and mixtures, even when genome information was scarce. This study further tested the previously developed proteomic-based spectra library-based approach was further tested to differentiate 29 fish species from the North Sea in individual samples, laboratory-prepared mixtures, and commercial samples. For authenticating libraries generated from 29 fish species, fresh muscle samples from the fish samples were matched against the reference libraries. Species of the fresh fish samples were correctly authenticated using the spectra libraries generated from the 29 fish species. Furthermore, processed commercial products containing mixtures of two or three fish species were matched against these spectra libraries to test the accuracy and robustness of this method for authentication of fish species. The results indicated that the method is suitable for the authentication of fish species from highly processed samples such as fish cakes and burgers. Spectra libraries built from 29 fish species in the North Sea can efficiently tackle current and future challenges in feed and food authentication analyses when prospecting new resources in the Arctic.
Project description:As described in our paper "Aspm knockout ferret reveals an evolutionary mechanism governing cerebral cortical size" (Johnson et al., Nature 2018), we used the standard Drop-seq method and analysis of Macosko et al. (2015) to capture, sequence, and analyze mRNA from single cells from Aspm wild-type, heterozygous, and knock-out littermate ferrets at embryonic day 35. Bulk reference samples were processed using standard Illumina mRNA-seq library prep and sequencing protocols, and the samples were described previously (Johnson, Wang et al., Nature Neurosci 2015)
Project description:Currently as of 29/05/2019:
https://www.cancerresearchuk.org/about-cancer/find-a-clinical-trial/a-trial-looking-aspirin-and-fish-oil-possible-way-preventing-small-growths-forming-bowel-seafood
Previously:
http://cancerhelp.cancerresearchuk.org/trials/a-trial-looking-aspirin-and-fish-oil-possible-way-preventing-small-growths-forming-bowel-seafood
Project description:Ricin, a protein found in castor seeds, is a lethal toxin that is designated as a category 2 select agent. Because castor seeds are easy to obtain and the toxin can be easily extracted, cases of attempted ricin poisoning are relatively common. A shotgun proteomics method for ricin identification has recently been developed (manuscript in preparation), in which ricin peptides are identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) followed by proteomics database search, and peptide-spectrum matches are verified and compared to standard spectra by a human expert. To make this process more reproducible, objective, and high-throughput, we have created a ricin spectral library for peptide identification to supplement the human review step. To construct these spectral libraries, two pure ricin samples (from a proposed standard reference material) and crude castor seed extracts were digested with trypsin and analyzed using a standard shotgun LC-MS/MS protocol. Spectral libraries were created from the filtered search results from four database search tools. The library was then used in a search using SpectraST on samples from castor seeds. Analysis showed that the spectral library search resulted in more peptides identified from crude castor seed samples compared to MS-GF+ and Sequest plus Percolator. These results suggest that computational comparison of putative ricin peptide spectra to library spectra can be an effective method of confirming the presence of ricin, and that spectral library search may be suitable to augment the more manual and subjective aspects of the currently recommended human expert review.
Project description:We performed a parallel analysis of commonly used pre- and post-bisulfite WGBS library preparation protocols for their performance and quality of sequencing outputs. Our results show that bisulfite conversion per se generates pronounced sequencing biases, and subsequent fragmentation and amplification steps lead to several-fold overrepresentation of these artefacts. Standard pre-bisulfite library preparation methods lead to a significantly biased genomic sequence representation and a marked overestimation of methylation levels. We have integrated a bias diagnostic tool in the Bismark package and propose that amplification-free and post-bisulfite procedures should become the gold standard for WGBS library preparation.
