Project description:Here we show the potential of proteins preserved in Pleistocene eggshell for addressing a longstanding controversy in human and evolution: the identity of the extinct bird that laid the eggs which were exploited by Australia’s first inhabitants. The eggs had been originally attributed to the iconic extinct flightless Genyornis newtoni, and subsequently dated to before 50 ±5 ka by Miller et al. (2016). This was taken to represent the extinction date for this endemic megafaunal species and thus implied a role of humans in its demise. A contrasting hypothesis, according to which the eggshell was laid by a large megapode (mound-builder), would therefore acquit humans of their responsibility in the extinction of Genyornis. Ancient protein sequences were reconstructed and used to assess the evolutionary proximity of the undetermined eggshell to extant birds, rejecting the megapode hypothesis. Ancient DNA could not be retrieved from these highly degraded samples, but morphometric data supported the attribution of the eggshell to Genyornis. When used in triangulation to address well-defined hypotheses, palaeoproteomics is a precious tool for reconstructing the evolutionary history of extinct and extant species. Here we show that the identification of Genyornis eggshell implies a more nuanced understanding of the modes of interactions between humans and their environment.
Project description:This is a biomolecular study of the intra-crystalline organic fraction of Late Cretaceous (~80 Ma) sauropod eggshell, which was found to be enriched in endogenous fully racemic amino acids (Glx, Gly, Ala, and Val). However, LC-MS/MS failed to detect any peptide sequences that could be confidently considered endogenous.
Project description:Claims for exceptional preservation of biomolecules in the fossil record are contested. Here we demonstrate the role of surface stabilisation in significantly prolonging protein sequence survival to ~3.8 million years. The intracrystalline environment of calcite ostrich (Struthionidae) eggshell encapsulates uterine proteins and molecular dynamics simulations of struthiocalcin-1 & -2, the dominant proteins within the eggshell, reveal that they bind to the mineral surface in distinct domains. By ~3.8 million years the struthiocalcin-1 domain with the lowest calculated binding energy is selectively preserved in eggshell samples from equatorial Africa. Sequence survival is explained by entropy loss of the peptide and water, lowering the effective temperature of the local environment at the peptide mineral interface.
Project description:The experiment was carried out to examine the effect of Srrt knockdown on the U1 snRNP/pre-mRNA interaction pattern. A2Lox mouse embryonic stem cells were transfected with either an Srrt-specific or a non-targeting siRNA. 48 hours post transfection the cells were cross-linked using 2% formaldehyde and lysed. RNA was partially fragmented by sonication, hybridized with U1 snRNA-specific biotinilated probes and pulled down. U1-associated RNA sequences were then purified and RNA-seq libraries were generated using a NEBNext® rRNA Depletion Kit and NEBNext® Ultra8482 II Directional RNA Library Preparation kit. Paired-end sequencing was performed using a HiSeq4000 75bp platform.
Project description:Cryptomonas sp. was grown under phototrophic conditions, glucose supplemented phototrophic conditions and 3 different dissolved organic carbon (DOC) concentrations: 1.5, 30 and 90 mg C l−1. The objective was to study the adaptations that make Cryptomonas sp. thrive under high DOC conditions.
Project description:The experiment was set to study the long term effect (16 weeks) of different meals in mice. Three groups of ten animals were fed on 1) beef with gravy, creamed peas and potatoes (beef), 2) salmon with barley, broccoli and milk powder (DSM), and 3) BigMac with potato chips, respectively (BigM).
Project description:Pleistocene Pongo teeth show substantial variation in size and morphology, fueling taxonomic debates about the paleodiversity of the genus. We investigated prominent features of the enamel-dentine-junction junction (EDJ) – phylogenetically informative internal structures – of 71 fossil Pongo lower molars from various sites by applying geometric morphometrics and conducted paleoproteomic analyses from enamel proteins to attempt to identify extinct orangutan species. Forty-three orangutan lower molars representing Pongo pygmaeus and Pongo abelii were included for comparison. The shape of the EDJ was analyzed by placing five landmarks on the tip of the main dentine horns, and 142 semilandmarks along the marginal ridges connecting the dentine horns. Paleoproteomic analyses were conducted on 15 teeth of Late Pleistocene Pongo using high-resolution tandem mass spectrometry. The geometric morphometric results show variations in EDJ shape regarding aspects of the height and position of the dentine horns and connecting ridges. Despite the issue of molar position and sample size, modern molars are distinguished from fossil counterparts by their elongated tooth outline and narrowly positioned dentine horns. Proteomic results show that neither a distinction of P. pygmaeus and P. abelii, nor a consistent allocation of fossil specimens to extant species is feasible. Based on the EDJ shape, the (late) Middle to Late Pleistocene Pongo samples from Vietnam share the same morphospace, supporting the previous allocation to P. devosi, although substantial overlap with Chinese fossils could also indicate close affinities with P. weidenreichi. The hypothesis that both species represent one chronospecies cannot be ruled out. Two fossil specimens, one from Tam Hay Marklot (Laos, Late Pleistocene), and another from Sangiran (Java, Early to Middle Pleistocene), along with some specimens within the Punung sample (Java), exhibit affinities with Pongo abelii. The Punung fossils might represent a mix of early Late Pleistocene and later specimens (terminal Pleistocene to Holocene) related to modern Pongo. The taxonomy and phylogeny of the complete Punung sample needs to be further investigated.
Project description:Palaeoproteomics of skeletal tissues has the potential to provide new insights into the evolutionary relationships between globally distributed hominin fossils across the Pleistocene. The use of alternative or additional proteases has the potential to increase both proteome size and protein. However, the potential of alternative proteases beside trypsin remains unexplored systematically in palaeoproteomic studies. Here, we present a comparison of the bone proteome size and protein sequence recovery of six different proteases from four Pleistocene bone specimens. We observe that the majority of the preserved bone proteome is inaccessible to trypsin. We also note that for proteins recovered consistently across several proteases, protein sequence coverage can be increased significantly by combining peptide identifications from two or more proteases. Our results thereby demonstrate that the proteolysis of Pleistocene proteomes by several proteases has clear advantages when addressing evolutionary questions in palaeoproteomics.
Project description:Most knowledge on spider venoms concerns neurotoxins acting on ion channels, whereas proteins and their significance for the envenomation process are neglected. The comprehensive analysis presented here of the venom gland transcriptome and proteome of Cupiennius salei with a focus on proteins and cysteine-containing peptides offers new insight into the structure and function of spider venom, presented here as dual prey-inactivation strategy. After venom injection, many enzymes and proteins, dominated by α-amylase, angiotensin-converting enzyme, and cysteine-rich secretory proteins, interact with main metabolic pathways, leading to major disturbance of the cellular homeostasis. Hyaluronidase and cytolytic peptides destroy tissue and membranes, thus supporting the spread of other venom compounds. We detected 81 transcripts of neurotoxins from 13 peptide families, whereof two families comprise 93.7% of all cysteine-containing peptides. This raises the question of the importance of the other low-expressed peptide families. The identification of a venom gland-specific defensin-like peptide and an aga-toxin-like peptide in the hemocytes offers an important clue on the recruitment and neofunctionalization of body proteins and peptides as the origin of toxins.