Biology subjects

Xiong, Z.

Publications and source records attributed to Xiong, Z..

At least 55 records · Page 3Linked to original sources

bioRxiv2023

In vivo evolution of a Klebsiella pneumoniae capsule defect promotes complement-mediated opsono-phagocytosis and persistence during recurrent infection

Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp) bloodstream infections rarely overwhelm the host but are associated with high mortality. The complement system is a key host defense against bloodstream infection. However, there are varying reports of serum resistance among KPC-Kp isolates. We assessed growth of 59 KPC-Kp clinical isolates in human serum and found increased resistance in 16/59 (27%). We identified five genetically-related bloodstream isolates with varying serum resistance profiles collected from a single patient during an extended hospitalization marked by recurrent KPC-Kp bloodstream infections. We noted a loss-of-function mutation in the capsule biosynthesis gene, wcaJ, that emerged during infection was associated with decreased polysaccharide capsule content, and resistance to complement-mediated killing. Surprisingly, disruption of wcaJ increased deposition of complement proteins on the microbial surface compared to the wild-type strain and led to increased complement-mediated opsono-phagocytosis in human whole blood. Disabling opsono-phagocytosis in the airspaces of mice impaired in vivo control of the wcaJ loss-of-function mutant in an acute lung infection model. These findings describe the rise of a capsular mutation that promotes KPC-Kp persistence within the host by enabling co-existence of increased bloodstream fitness and reduced tissue virulence. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=124 SRC="FIGDIR/small/542722v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@155736eorg.highwire.dtl.DTLVardef@10d47c0org.highwire.dtl.DTLVardef@e1ab83org.highwire.dtl.DTLVardef@1c33131_HPS_FORMAT_FIGEXP M_FIG Graphical abstract Created with BioRender.com C_FIG

microbiology↗

bioRxiv2023

Printing double network tough hydrogels using Temperature-Controlled Projection Stereolithography (TOPS)

We report a new method to shape double-network (DN) hydrogels into customized microscale 3D structures that exhibit superior mechanical properties in both tension and compression. A one-pot prepolymer formulation containing photo-cross-linkable acrylamide and thermo-reversible sol-gel {kappa}-carrageenan with a suitable crosslinker, and photo-initiator/absorbers are optimized. A new TOPS system is utilized to photo-polymerize the primary acrylamide network into a 3D structure above the sol-gel transition of {kappa}-carrageenan (80{degrees}C), while cooling down generates the secondary physical {kappa}-carrageenan network to realize tough DN hydrogel structures. 3D structures, printed with high lateral (37m) and vertical (180m) resolutions and superior 3D design freedoms (internal voids), exhibit ultimate stress and strain of 200 kPa and 2400% respectively under tension, and simultaneously exhibit high compression stress of 15 MPa with a strain of 95%, both with high recovery rates. The roles of swelling, necking, self-healing, cyclic loading, dehydration, and rehydration on the mechanical properties of printed structures are also investigated. To demonstrate the potential of this technology to make mechanically reconfigurable flexible devices, we print an axicon lens and show that a Bessel beam can be dynamically tuned via user-defined tensile stretching of the device. This technique can be broadly applied to other hydrogels to make novel smart multifunctional devices for a range of applications.

bioengineering↗

bioRxiv2023

Long-term reliable neural decoding based on flexible implantable microelectronics and machine learning for seizure prediction application

Neural decoding is useful for understanding brain functions and developing neural interface applications. However, neural interfaces based on rigid electronics often suffer from recording instability due to the foreign body responses caused by their mechanical mismatch with soft tissues, limiting the longitudinal accuracy of neural decoding methods. Herein, it is reported that flexible electronics can be integrated with machine learning algorithms to achieve long-term reliable neural decoding. Wet-spun conductive polymer microfibers showed mechanical robustness and flexibility, low impedance, and chronic biocompatibility, enabling intracerebral neural recordings in epileptic mice at a high signal-to-noise ratio eight weeks after implantation. When the signals recorded by the flexible electrodes were used in machine learning analyses with diverse complex algorithms, they consistently showed higher prediction accuracy for epileptic seizures than stiff metal electrode signals, particularly in the case of using long-term recordings for testing or small-sample datasets for training. A real-time warning system based on the flexible neural electrodes was built that predicted seizures eight minutes in advance with a low false alarm rate. Our work bridges flexible electronics and artificial intelligence for neural decoding applications such as long-term treatment of chronic neurological disorders.

bioengineering↗

bioRxiv2022

Small Molecule Screen Identifies Pyrimethamine as an Inhibitor of NRF2-driven Esophageal Hyperplasia

ObjectiveNRF2 is a master transcription factor that regulates the stress response. NRF2 is frequently mutated and activated in human esophageal squamous cell carcinoma (ESCC), which drives resistance to chemotherapy and radiation therapy. Therefore, a great need exists for NRF2 inhibitors for targeted therapy of NRF2high ESCC. DesignWe performed high-throughput screening of two compound libraries from which hit compounds were further validated in human ESCC cells and a genetically modified mouse model. The mechanism of action of one compound was explored by biochemical assays. ResultsUsing high-throughput screening of two small molecule compound libraries, we identified 11 hit compounds as potential NRF2 inhibitors with minimal cytotoxicity at specified concentrations. We then validated two of these compounds, pyrimethamine and mitoxantrone, by demonstrating their dose- and time-dependent inhibitory effects on the expression of NRF2 and its target genes in two NRF2Mut human ESCC cells (KYSE70 and KYSE180). RNAseq and qPCR confirmed the suppression of global NRF2 signaling by these two compounds. Mechanistically, pyrimethamine reduced NRF2 half-life by promoting NRF2 ubiquitination and degradation in KYSE70 and KYSE180 cells. Expression of an Nrf2E79Q allele in mouse esophageal epithelium (Sox2CreER;LSL-Nrf2E79Q/+) resulted in an NRF2high phenotype, which included squamous hyperplasia, hyperkeratinization, and hyperactive glycolysis. Treatment with pyrimethamine (30mg/kg/day, p.o.) suppressed the NRF2high esophageal phenotype with no observed toxicity. ConclusionWe have identified and validated pyrimethamine as an NRF2 inhibitor that may be rapidly tested in the clinic as a radiation and chemotherapy sensitizer for NRF2high ESCC. SummaryO_ST_ABSWhat is already known on this topic - summarise the state of scientific knowledge on this subject before you did your study and why this study needed to be doneC_ST_ABSO_LIMutational activation of the NRF2 transcription factor drives ESCC progression and therapeutic resistance. Targeted therapies to block NRF2 have not yet been realized, despite great needs. C_LI What this study adds - summarise what we now know as a result of this study that we did not know beforeO_LIA screen of >35,000 small molecules identified eleven potential NRF2 inhibitors. Pyrimethamine and mitoxantrone were validated to inhibit the expression of NRF2 and NQO1 in human ESCC cells in both dose- and time-dependent manners. C_LIO_LIPyrimethamine enhanced NRF2 protein ubiquitination and degradation, resulting a decreased half-life. C_LIO_LIA genetically modified mouse model was established to express the Nrf2E79Q mutant allele in the mouse esophageal epithelium upon tamoxifen induction. Pyrimethamine suppressed the NRF2high esophageal phenotype induced by the mutant allele. C_LI How this study might affect research, practice or policy - summarise the implications of this studyO_LIAs an FDA-approved drug, Pyrimethamine has the potential for immediate translation to a clinical trial on NRF2high ESCC in humans. C_LIO_LIFurther exploration of its mechanisms of action may lead to more potent NRF2 inhibitors for future use. C_LI

cancer biology↗

bioRxiv2022

Citrus genomic resources unravel putative genetic determinants of Huanglongbing, a pathogen-triggered immune disease

Citrus is one of the most important tree crops worldwide and citrus production is threatened by Huanglongbing (HLB), a devasting citrus disease caused by Candidatus Liberibacter. HLB is a pathogen-triggered immune disease, in which the pathogen initiates systemic and chronic immune responses including the excessive production of reactive oxidative species, which subsequently lead to cell death of phloem tissues and HLB disease symptoms. Here, we identified putative genetic determinants of HLB pathogenicity by integrating citrus genomic resources to characterize the pan-genome of accessions that differ in their response to HLB. Genome-wide association mapping and analysis of allele-specific expression between susceptible, tolerant, and resistant accessions further refined candidates underlying the response to HLB. To enable these analyses we first developed a phased diploid assembly of Citrus sinensis Newhall genome and produced resequencing data for 91 citrus accessions that differ in their response to HLB. These data were combined with previous resequencing data from 356 sequenced accessions for genome-wide association mapping of the HLB response. Genes with HLB pathogenicity were associated with the host immune response, ROS production, and antioxidants. Overall, this study has provided a significant recourse of citrus genomic data and we have identified candidate genes to be further explored to understand the genetic determinants of HLB pathogenicity and to generate HLB resistant/tolerant citrus varieties.

genomics↗

bioRxiv2022

Naturally occurring Alzheimer's disease in rhesus monkeys

Alzheimers disease (AD) is the most common neurodegenerative disease. To date, its cause is unclear and there are no effective treatments or preventive measures. Despite there are accumulating evidences for the existence of AD pathological hallmarks in the brain of aging rhesus monkeys, it remains a mainstream notion that monkeys do not develop AD naturally. This is an important issue because it will determine how we use monkeys in AD studies. To settle down this issue, a group (n=10) of aged rhesus monkeys 26 years old or above went through a systematic AD screening procedure in this study. Three of these monkeys showed severe memory impairments (SMI) after evaluated with a classic working memory test. Further behavioral testing revealed that the SMI monkeys also exhibited apathy-like behavior, which is another core AD clinical symptom. In addition to the cognitive deficits, two of the three SMI monkeys developed all of the three AD pathological hallmarks, including neurofibrillary tangles, senile plaques and neuronal loss. According to the diagnostic criteria of human AD, the two SMI monkeys were clearly naturally occurring AD monkeys. These results suggest that AD is not a uniquely human disease and monkeys have great potential for the development of much needed etiological AD models, which are vital for better understanding of developmental process of AD and the base of identification of early diagnostic biomarkers and effective therapeutic targets of AD.

neuroscience↗

bioRxiv2022

Neural correlates of an illusive sense of agency caused by virtual reality

Sense of agency (SoA) is the sensation that self-actions lead to ensuing perceptual consequences. The prospective mechanism emphasizes that SoA arises from motor prediction and its comparison with actual action outcomes, while the reconstructive mechanism stresses that SoA emerges from retrospective causal processing about the action outcomes. Consistent with the prospective mechanism, motor planning regions were identified by neuroimaging studies using the temporal binding effect, a behavioral measure often linked to implicit SoA. Yet, temporal binding also occurs during passive observation of anothers action, lending support to the reconstructive mechanism, but its neural correlates remain unexplored. Here, we employed virtual reality (VR) to modulate such observation-based SoA and examined it with functional magnetic resonance imaging. After manipulating an avatar hand in VR, participants passively observed an avatars "action" and showed a significant increase in temporal binding. The binding effect was associated with the right angular gyrus and inferior parietal lobule, which are critical nodes for inferential and agency processing. These results suggest that the experience of controlling an avatar may potentiate inferential processing within the right inferior parietal cortex and give rise to the illusionary sense of agency without voluntary action.

neuroscience↗

bioRxiv2022

A reductase in the lipid metabolism at cross roads between cuticular wax production and jasmonic acid-mediated defenses in maize

Cuticular wax is the first physical layer to protect plants from herbivore infestations. Although wax and jasmonic acid (JA) biosynthesis are the two most studied branches of lipid metabolism, the mechanism how cuticular wax production modulates plant chemical defenses is unclear. Here, we show that the maize (Zea mays) GL8 gene, encoding 3-ketoacyl reductase during fatty acid elongation in the biosynthesis of very long chain fatty acids (VLCFA), functions as a turning point between wax production and JA-mediated defenses. The fall armyworm (Spodoptera frugiperda) larvae consumed more tissue but gained a lower performance on gl8/Ye478 mutant plants. gl8/Ye478 mutant displayed higher JA-mediated defenses constitutively, and also more inducible by herbivore stimulation. The comprehensive transcriptomic and lipidomic analyses further demonstrated that ZmGL8 mutation up-regulates the JA biosynthesis pathway by promoting the accumulation of lysophospholipids and modulation of galactolipid synthase genes ZmDGD and ZmMGD. The phenotypic and transcription comparisons of the maize and Arabidopsis wax-deficient mutants suggest a conserved wide-spread trade-off between wax production and chemical defense in both 18:3 and 16:3 plants. These results illustrate a critical role of VLCFA metabolism as a switch to control the balance between cuticular wax physical barrier and JA-mediated chemical defenses during plant-herbivore coevolution history.

plant biology↗

bioRxiv2022

PanGu Drug Model: Learn a Molecule Like a Human

Recent achievements in large-scale pre-trained models like GPT-3 and PanGu- showed amazing performances in many downstream tasks, which makes AI friendlier toward industrial users. Deep learning has been recognized as the most promising technology for pharmaceuticals, a powerful molecule pre-trained model could save researchers tons of time. In chemistry classes, the students learn two molecule representations, the molecular formula and the structure formula, and learn to translate them from one way to the other. Inspired by this, we developed a novel deep learning architecture using a graph-to-sequence asymmetric conditional variational autoencoders, called PanGu Drug Model, which can appropriately characterize the molecule from both representations and improve the performance of downstream drug discovery tasks. After pretrained with 1.7 billion small molecules, our proposed model achieved the state-of-the-art results in 20 drug discovery tasks, such as molecule property prediction (predict ADMET properties, compound-target interactions, drug-drug interactions and chemical reaction productivity), molecule generation and molecule optimization. A new drug screening library of 100 million drug-like small molecules with 99.68% novelty was generated by PanGu molecule generator, which could efficiently produce novel compounds with similar physiochemical properties to given distribution, this library could be used to supplement existing compound databases. In addition, PanGu molecule optimizer could optimize the chemical structures of starting molecule with improved molecular property of interest. An automatic multi-objective optimization web application implemented by PanGu Drug Model is available at http://www.pangu-drug.com/.

biochemistry↗

bioRxiv2022

Planting graphene quantum dots in PEGylated nanoparticles for enhanced and multimodal in vivo imaging of tumor

Photoluminescent graphene quantum dots (GQDs) have recently attracted considerable attention for biomedical applications owing to the interesting physicochemical and photophysical properties, and prominent biocompatibility and biosafety. However, although much progress has been achieved in therapy and in vitro bioimaging, broad and crucial in vivo fluorescence bioimaging and synergistically working with other nanomedicine are very challenging and limited. Herein, we in situ implanted GQDs in the PEGylated layer of nanoparticles (NPs) via a bottom-up approach to obtain the NPs (core)-GQDs-PEG multifunctional nanoprobe (NPC-GQDs-PEG), which prolonged the blood circulation of GQDs more than four times and increased the tumor accumulation 7~8 times than GQDs used alone. Under assisted by the flexible microscope, the GQDs were successfully used for in vivo real-time monitoring of local NPs pharmacokinetics, in vivo multimodality imaging, and fluorescence imaging-guided tumor surgery. The approach of implanting GQDs in PEGylated nanomedicine and synergistic working provide a new strategy for in vivo biomedical applications of GQDs.

cancer biology↗

bioRxiv2022

Structural insights as to how iron-loaded siderophores are imported into Mycobacterium tuberculosis by IrtAB

The ATP-binding cassette (ABC) transporter, IrtAB, plays a vital role in the replication and viability of Mycobacterium tuberculosis (Mtb), where its function is to import iron-loaded siderophores. Unusually, it adopts the typical fold of canonical ABC exporters. Here, we report the structure of unliganded Mtb IrtAB and its structure in complex with ATP, ADP, and an ATP analogue (AMP-PNP) at resolutions from 2.9 to 3.5 [A]. In the ATP-bound state, the two nucleotide-binding domains (NBDs) form a "head-to-tail" dimer, but IrtAB has an unexpectedly occluded conformation, with the inner core forming a large hydrophilic cavity of about 4600 [A]3. Comparison of the structure of the transporter in inward-facing and occluded conformations reveals that the NBD and the intracellular helical region of transmembrane domain (TMD) have an asymmetric allosteric mechanism when ATP binding/hydrolysis such that the one exhibits rigid-body rotation and the other moves in a concerted response as a rigid body. This study provides a molecular basis for the ATP-driven conformational changes that occur in IrtAB and an explanation as to how iron-loaded siderophores are imported into Mtb by IrtAB.

molecular biology↗

bioRxiv2021

A genome in flux: homoeologous exchanges, subgenome dominance, and gene dosage balance constraints in resynthesized allopolyploid Brassica napus

The Gene Balance Hypothesis (GBH) proposes that selection acts on the dosage (i.e. copy number) of genes within dosage-sensitive portions of networks, pathways, and protein complexes to maintain balanced stoichiometry of interacting proteins, because perturbations to stoichiometric balance can result in reduced fitness. This selection has been called dosage balance selection. Dosage balance selection is also hypothesized to constrain expression responses to dosage changes, making dosage-sensitive genes (those encoding members of interacting proteins) experience more similar expression changes. In allopolyploids, where whole-genome duplication involves hybridization of diverged lineages, organisms often experience homoeologous exchanges (HEs) that recombine, duplicate, and delete homoeologous regions of the genome and alter the expression of homoeologous gene pairs. Although the GBH makes predictions about the expression response to HEs, they have not been empirically tested. We used genomic and transcriptomic data from six resynthesized, isogenic Brassica napus lines over ten generations to identify HEs, analyzed expression responses, and tested for patterns of genomic imbalance. Groups of dosage-sensitive genes had less variable expression responses to HEs than dosage-insensitive genes, a sign that their relative dosage is constrained. This difference was absent for homoeologous pairs whose expression was biased toward the BnA subgenome. Finally, the expression response to HEs was more variable than the response to WGD, suggesting HEs create genomic imbalance. These findings expand our knowledge of the impact of dosage balance selection on genome evolution and potentially connect patterns in polyploid genomes over time; from homoeolog expression bias to duplicate gene retention.

evolutionary biology↗

bioRxiv2021

GMQN: A reference-based method for correcting batch effects as well as probes bias in HumanMethylation BeadChip

Illumina HumanMethylation BeadChip is one of the most cost-effective ways to quantify DNA methylation levels at the single-base level across the human genome, which makes it a routine platform for epigenome-wide association studies. It has accumulated tens of thousands of DNA methylation array samples in public databases, thus provide great support for data integration and further analysis. However, majority of public DNA methylation data are deposited as processed data without background probes which are widely used in data normalization. Here we present Gaussian mixture quantile normalization (GMQN), a reference based method for correcting batch effects as well as probes bias in HumanMethylation BeadChip. Availability and implementation: https://github.com/MengweiLi-project/gmqn.

bioinformatics↗

bioRxiv2021

Gene regulatory network analysis identifies key genes and regulatory mechanisms involved in acute myocardial infarction using bulk and single cell RNA-seq data

Cardiovascular and cerebrovascular diseases are leading causes of death worldwide, accounting for more than 40% of all deaths in China. Acute myocardial infarction (AMI) is a common cardiovascular disease and traditionally divided into ST-segment (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI), which are known with different prognoses and treatment strategies. However, key regulatory genes and pathways involved in AMI that may be used as potential biomarker for prognosis are unknown. In this study, we constructed weighted gene co-expression networks for differential expressed genes between STEMI and NSTEMI patients based on whole-blood RNA-seq transcriptomics. Network topological attributes (e.g., node degree, betweenness) were analyzed to identify key genes involved in different functional network modules. Furthermore, we used single-cell RNA-seq data to construct multilayer signaling network to infer regulatory mechanisms of the above key genes. PLAUR (receptor for urokinase plasminogen activator) was found to play a vital role in transducing inter-cellular signals from endothelial cells and fibroblast cells to intra-cellular pathways of myocardial cells, leading to gene expression involved in cellular response to hypoxia. Our study sheds lights on identifying molecular biomarkers for diagnosis and prognosis of AMI, and provides candidate key regulatory genes for further experimental validation.

bioinformatics↗

bioRxiv2021

SUMO E2/E3 Enzyme Co-Recognize Substrates and Confers High Substrates Specificity

Although various technologies can determine protein-protein interaction affinity, Kd, current approaches require at least one interacting protein to be purified. Here, we present a development of high-throughput approach to determine protein interaction affinity for un-purified interacting proteins using quantitative FRET assay. We developed this approach first using SUMO E2 conjugating enzyme, Ubc9, and SUMO substrate, RanGap1c. The interaction affinities from two purified proteins and two unpurified proteins in the presence of BSA, bacterial extracts or two mixtures are all in excellent agreement with that obtained from the SPR measurement. We then applied this approach to determine the interaction affinities of SUMO E3 PIAS1 and Ubc9 with a SUMO substrate, influenza virus protein, NS1, and, for the first time, the SUMO E3 ligase-substrate interaction affinity is determined, which enables us to provide a kinetics explanation for the two-enzyme substrate recognition mode. In general, our studies allow high-throughput determination of protein interacting affinity without any purification, and both the approach and scientific discoveries can be applied to proteins that are difficult to be expressed in general. O_LIProtein interaction dissociation constant, Kd, determination without any protein purification; C_LIO_LICo-recognition of substrates by two enzymes in one reaction; C_LIO_LIPotential affinity improvement mechanism of substrate recognition revealed with kinetics parameters in vivo. C_LI

biochemistry↗

bioRxiv2021

Convergence of MCR-8.2 and chromosome-mediated resistance to colistin and tigecycline in an NDM-5-producing ST656 Klebsiella pneumoniae from a lung transplant patient

For infection caused by NDM-5-producing Klebsiella pneumoniae, tigecycline and colistin are the last treatment options. In this study, we characterized the first NDM-5 and MCR-8.2 co-harboring K. pneumoniae clinical isolate, combining with chromosomal gene-mediated resistance to colistin and tigecycline. The K. pneumoniae KP32558 was isolated from the bronchoalveolar lavage fluid from a lung transplant male patient. Whole genome sequencing was carried out using Illumina HiSeq sequencing platform as well as nanopore sequencing method. The K. pneumoniae KP32558 was identified as a pan-drug resistant bacteria, belonged to ST656, and harbored plasmid-encoded blaNDM-5 and mcr-8.2 genes. The blaNDM-5 gene was located on an IncX3 type plasmid, which was successfully transferred to Escherichia coli strain J53 without visible fitness cost. The mcr-8.2 gene was located on a conjugative plasmid pKP32558-2-mcr8. It had two replicons, IncFII(K) and IncQ1, harbored previously by another two mcr-8.2-carrying plasmids pMCR8_020135 and pMCR8_095845. These three plasmids were clustered into the same clade and derived from K. pneumoniae isolates of the same clonal complex, indicating that pKP32558-2-mcr8 may come from pMCR8_020135 and pMCR8_095845 related ancestor. The MIC of KP32558 for colistin was 256 mg/L, the 6 amino acid substitutions in the two-component system may involve in the high-level colistin resistance. The truncation in acrR gene, related to tigecycline resistance, was also identified. K. pneumoniae has evolved a variety of complex resistance mechanisms to the last-resort antimicrobials, close surveillance is urgently needed to monitor the prevalence of this clone.

microbiology↗

bioRxiv2021

Regulation of osteoblast autophagy based on PI3K/AKT/mTOR signaling pathway study on the effect of β-ecdysterone on fracture healing

PurposeTo investigate the effects of {beta}-ecdysterone on fracture healing and the underlying mechanism. MethodsMTT assay was used to detect the cell viability and alkaline phosphatase (ALP) activity was measured using a commercial kit. AO/PI and flow cytometry assays were used to determine the state of apoptosis of osteoblasts. The expression level of RunX2, ATG7 and LC3 was evaluated by qRT-PCR and Western blot assays. X-ray and HE staining were conducted on the fractured femur to evaluate the pathological state. Immunohistochemical assay was used to detect the expression level of Beclin-1 and immunofluorescence assay was used to measure the expression level of LC3 in the fractured femurs. Western blot was utilized to determine the expression level of PI3K, p-AKT1, AKT1, p-mTOR, mTOR, p-p70S6K, and p70S6K. ResultsThe ALP activity and expression of RunX2 in fractured osteoblasts were significantly suppressed by 3-methyladenine and elevated by rapamycin, 60, and 80 M {beta}-ecdysterone. The apoptotic state of fractured osteoblasts was enhanced by 3-methyladenine and alleviated by rapamycin, 60, and 80 M {beta}-ecdysterone. The state of autophagy both in fractured osteoblasts and femurs was inhibited by 3-methyladenine and facilitated by rapamycin and {beta}-ecdysterone. Compared to control, Garrett score in 3-methyladenine group was significantly decreased and promoted in rapamycin and {beta}-ecdysterone groups, accompanied by ameliorated pathological state. Lastly, the PI3K/AKT/mTOR pathway both in fractured osteoblasts and femurs was activated by 3-methyladenine and inhibited by rapamycin and {beta}-ecdysterone. Conclusion{beta}-ecdysterone might facilitate fracture healing by activating autophagy through suppressing PI3K/AKT/mTOR signal pathway.

animal behavior and cognition↗

bioRxiv2021

Construction of a neural network energy function for protein physics

Classical potentials are widely used to describe protein physics, due to their simplicity and accuracy, but they are continuously challenged as real applications become more demanding with time. Deep neural networks could help generating alternative ways of describing protein physics. Here we propose an unsupervised learning method to derive a neural network energy function for proteins. The energy function is a probability density model learned from plenty of 3D local structures which have been extensively explored by evolution. We tested this model on a few applications (assessment of protein structures, protein dynamics and protein sequence design), showing that the neural network can correctly recognize patterns in protein structures. In other words, the neural network learned some aspects of protein physics from experimental data.

biophysics↗