Biology subjects

Sun, P.

Publications and source records attributed to Sun, P..

4 recordsLinked to original sources

bioRxiv2018

Rules Governing Perception of Multiple Phosphenes by Human Observers

Stimulation of single sites in primary visual cortex results in the perception of a small flash of light known as a phosphene. Little is known about how phosphenes from multiple electrodes can be combined to form perception of coherent patterns. Here we examine the percepts reported by human observers as various spatial configurations of 2 to 5 electrodes in visual cortex were stimulated simultaneously. When two electrodes were stimulated simultaneously, subjects reliably perceived either one or two phosphenes depending on the physical distance separating the electrodes. In cases where two phosphenes were perceived, they were located in the same visual field location as when the two electrodes were stimulated separately. Adding a third electrode produced similar results. In several subjects, we obtained combination of 4 to 5 electrodes that generated individual phosphenes when stimulated concurrently. Subjects were able to reliably discriminate between different multiple electrode stimulation patterns that were presented in random order. These results demonstrate that simple pattern information can be conveyed to subjects with surface electrodes spaced at millimeters apart on the cortex.

neuroscience↗

bioRxiv2018

Identification of protein abundance changes in biopsy-level hepatocellular carcinoma tissues using PCT-SWATH

In this study, we optimized the pressure-cycling technology (PCT) and SWATH mass spectrometry workflow to analyze biopsy-level tissue samples (2 mg wet weight) from 19 hepatocellular carcinoma (HCC) patients. Using OpenSWATH and pan-human spectral library, we quantified 11,787 proteotypic peptides from 2,579 SwissProt proteins in 76 HCC tissue samples within about 9 working days (from receiving tissue to SWATH data). The coefficient of variation (CV) of peptide yield using PCT was 32.9%, and the R2 of peptide quantification was 0.9729. We identified protein changes in malignant tissues compared to matched control samples in HCC patients, and further stratified patient samples into groups with high -fetoprotein (AFP) expression or HBV infection. In aggregate, the data identified 23 upregulated pathways and 13 ones. We observed enhanced biomolecule synthesis and suppressed small molecular metabolism in liver tumor tissues. 16 proteins of high documented relevance to HCC are highlighted in our data. We also identified changes of virus-infection-related proteins including PKM, CTPS1 and ALDOB in the HBV+ HCC subcohort. In conclusion, we demonstrate the practicality of performing proteomic analysis of biopsy-level tissue samples with PCT-SWATH methodology with moderate effort and within a relatively short timeframe.

systems biology↗

bioRxiv2018

ErbB4 deletion in noradrenergic neurons in the locus coeruleus induces mania-like behavior via elevated catecholamines

Dysfunction of the noradrenergic (NE) neurons is implicated in the pathogenesis of manic-depressive psychosis (MDP). ErbB4 is highly expressed in NE neurons, and its genetic variation has been linked to MDP; however, how ErbB4 regulates NE neuronal function and contributes to MDP pathogenesis is unclear. Here we find that conditional deletion of ErbB4 in locus coeruleus (LC) NE neurons increases neuronal spontaneous firing through NMDA receptor hyperfunction, and elevates catecholamines in the cerebrospinal fluid (CSF). Furthermore, ErbB4-deficient mice present mania-like behaviors, including hyperactivity, reduced anxiety and depression, and increased sucrose preference. These behaviors are completely rescued by the anti-manic drug lithium or antagonists of catecholaminergic receptors. Our study demonstrates the critical role of ErbB4 signaling in regulating LC-NE neuronal function, reinforcing the view that dysfunction of the NE system may contribute to the pathogenesis of mania-associated disorder.

neuroscience↗

bioRxiv2017

Overlooked polyploidies in lycophytes generalize their roles during the evolution of vascular plants

Seed plants and lycophytes constitute the extant vascular plants. As a model lycophyte, Selaginalla moellendroffii was deciphered its genome, previously proposed to have avoided polyploidies, as key events contributing to the origination and fast expansion of seed plants. Here, using a gold-standard streamline recently proposed to deconvolute complex genomes, we reanalyzed the S. moellendroffii genome. To our surprise, we found clear evidence of multiple paleo-polyploidies, with one being recent (~ 13-15 millions of years ago or Mya), another one occurring about ~125-142 Mya, during the evolution of lycophytes, and at least 2 or 3 events being more ancient. Besides, comparison of reconstructed ancestral genomes of lycophytes and angiosperms shows that lycophytes were likely much more affected by paleo-polyploidies than seed plants. The present analysis here provides clear and solid evidence that polyploidies have contributed the successful establishment of all vascular plants on earth.

evolutionary biology↗