Biology subjects

Han, Q.

Publications and source records attributed to Han, Q..

3 recordsLinked to original sources

bioRxiv2018

Fast-backward replay of sequentially memorized items in humans

Storing temporal sequences of events (i.e., sequence memory) is fundamental to many cognitive functions. However, how the sequence order information is maintained and represented in working memory and its behavioral significance, particularly in human subjects, remains unknown. Here, we recorded electroencephalography (EEG) in combination with a temporal response function (TRF) method to dissociate item-specific neuronal reactivations. We demonstrate that serially remembered items are successively reactivated during memory retention. The sequential replay displays two interesting properties compared to the actual sequence. First, the item-by-item reactivation is compressed within a 200-400 ms window, suggesting that external events are associated within a plasticity-relevant window to facilitate memory consolidation. Second, the replay is in a temporally reversed order and is strongly related to the recency effect in behavior. This fast-backward replay, previously revealed in rat hippocampus and demonstrated here in human cortical activities, might constitute a general neural mechanism for sequence memory and learning.

neuroscience↗

bioRxiv2018

Identification of Common Adulterants in Walnut Beverage Based on Plant DNA Barcode Technology

Walnut beverage is a common vegetable protein drink that is rich in proteins and has a wide consumption market. In this study, a plant DNA barcode technology was used to establish a method to identify common adulterated ingredients (peanut and soybean) in walnut beverage. In this experiment, universal primers were designed, and PCR amplification was performed. The universal primers were screened by sequencing and comparing the amplified products. Results showed that the primers rbcL-4 and matK-4 amplified walnut, peanut, sesame, soybean, and hazelnut. Peanut genomic DNA and soybean genomic DNA were added to the genomic DNA of walnut in different proportions. Primer rbcL-4 can detect 10% peanut genome DNA, and primer matK-4 can detect 10% soybean genome DNA. Calculation results of the extraction rate revealed that primer rbcL-4 can detect 8.88% peanut raw materials and primer matK-4 can detect 2.30% soybean raw materials. The combination of these two primers can be used as a universal primer for the identification of adulterated components in walnut beverage. This experiment could serve as a theoretical reference for related research and detection.

molecular biology↗

bioRxiv2017

Hijacking of Multiple Phospholipid Biosynthetic Pathways and Induction of Membrane Biogenesis by a Picornaviral 3CD Protein

RNA viruses induce specialized membranous structures for use in genome replication. These structures are often referred to as replication organelles (ROs). ROs exhibit distinct lipid composition relative to other cellular membranes. In many picornaviruses, phosphatidylinositol-4-phosphate (PI4P) is a marker of the RO. Studies to date indicate that the viral 3A protein hijacks a PI4 kinase to induce PI4P by a mechanism unrelated to the cellular pathway, which requires Golgi-specific brefeldin A-resistance guanine nucleotide exchange factor 1, GBF1, and ADP ribosylation factor 1, Arf1. Here we show that a picornaviral 3CD protein is sufficient to induce synthesis of not only PI4P but also phosphatidylinositol-4,5-bisphosphate (PIP2) and phosphatidylcholine (PC). Synthesis of PI4P requires GBF1 and Arf1. We identified 3CD derivatives: 3CDm and 3CmD, that we used to show that distinct domains of 3CD function upstream of GBF1 and downstream of Arf1 activation. These same 3CD derivatives still supported induction of PIP2 and PC, suggesting that pathways and corresponding mechanisms used to induce these phospholipids are distinct. Phospholipid induction by 3CD is localized to the perinuclear membrane, the outcome of which is the proliferation of membranes in this area of the cell. We conclude that a single viral protein can serve as a master regulator of cellular phospholipid and membrane biogenesis, likely by commandeering normal cellular pathways.\n\nAUTHOR SUMMARYPicornaviruses replicate their genomes in association with host membranes. Early during infection, existing membranes are used but remodeled to contain a repertoire of lipids best suited for virus multiplication. Later, new membrane synthesis occurs, which requires biosynthesis of phosphatidylcholine in addition to the other more specialized lipids. We have learned that a single picornaviral protein is able to induce membrane biogenesis and decorate these membranes with some of the specialized lipids induced by the virus. A detailed mechanism of induction has been elucidated for one of these lipids. The ability of a single viral protein to commandeer host pathways that lead to membrane biogenesis was unexpected. This discovery reveals a new target for antiviral therapy with the potential to completely derail all aspects of the viral lifecycle requiring membrane biogenesis.

biochemistry↗