Publications by authors named "Yuxuan Sun"

17 Publications

  • Page 1 of 1

A UoI-Optimal Policy for Timely Status Updates with Resource Constraint.

Entropy (Basel) 2021 Aug 20;23(8). Epub 2021 Aug 20.

Beijing National Research Center for Information Science and Technology, Department of Electronic Engineering, Tsinghua University, Beijing 100084, China.

Timely status updates are critical in remote control systems such as autonomous driving and the industrial Internet of Things, where timeliness requirements are usually context dependent. Accordingly, the Urgency of Information (UoI) has been proposed beyond the well-known Age of Information (AoI) by further including context-aware weights which indicate whether the monitored process is in an emergency. However, the optimal updating and scheduling strategies in terms of UoI remain open. In this paper, we propose a UoI-optimal updating policy for timely status information with resource constraint. We first formulate the problem in a constrained Markov decision process and prove that the UoI-optimal policy has a threshold structure. When the context-aware weights are known, we propose a numerical method based on linear programming. When the weights are unknown, we further design a reinforcement learning (RL)-based scheduling policy. The simulation reveals that the threshold of the UoI-optimal policy increases as the resource constraint tightens. In addition, the UoI-optimal policy outperforms the AoI-optimal policy in terms of average squared estimation error, and the proposed RL-based updating policy achieves a near-optimal performance without the advanced knowledge of the system model.
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http://dx.doi.org/10.3390/e23081084DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8393192PMC
August 2021

Control strategies for the vertical gene transfer of quinolone ARGs in Escherichia coli through molecular modification and molecular dynamics.

J Hazard Mater 2021 Jul 16;420:126667. Epub 2021 Jul 16.

College of Forestry, Northeast Forestry University, No. 26 Hexing Road, Harbin 150040, China. Electronic address:

This study investigates the regulation of the vertical gene transfer of quinolones' antibiotic resistance genes (ARGs) through a combination of source modification and process control. In source prevention, 29 Escherichia coli (E. coli) DNA gyrase subunit A mutant proteins were constructed, the B-G mutant protein displayed the greatest reduction in binding effect (-25.98%). Based on this, a 3D-QSAR model was constructed, and LEV-2 and LEV-9 QNs derivatives were designed based on Levofloxacin (LEV), and their binding effect with B-G mutant protein was found be increased by 13.24% and 19.40%. The drug resistance mechanism of E. coli was explored based on molecular docking technology and protein hydrophobic interaction theory. Most of the amino acid resistance mutations changed from hydrophilic to lipophilic, which inhibited the binding of QNs to mutant protein A subunit, and further reduced the bactericidal effect of QNs. In process control, Huoxiang-Zhengqi, stroke-physiological saline solution (SPSS), and Lycium barbarum (L. barbarum) was found to be 164.82% higher than that of the blank control group. The purpose of this study is to provide a theoretical support for the joint regulation of QNs' ARGs in organisms and the research and development on green alternatives to QNs compounds.
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http://dx.doi.org/10.1016/j.jhazmat.2021.126667DOI Listing
July 2021

Photocatalytic Penicillin Degradation Performance and the Mechanism of the Fragmented TiO Modified by CdS Quantum Dots.

ACS Omega 2021 Jul 9;6(28):18178-18189. Epub 2021 Jul 9.

College of Forestry, Northeast Forestry University, Harbin 150040, China.

In this study, a novel method was adopted to construct a CdS-TiO heterostructure to degrade penicillin under sunlight. A potato extract was used during the synthesis process of CdS QDs as a stabilizer and a modifier. The CdS-TiO composite with a heterostructure delivers high photocatalytic degradation efficiency. In detail, 0.6 mg/mL of CdS-TiO can successfully decompose penicillin after 2 h, and 5‰ CdS-TiO shows the optimal degradation efficiency with the degradation rate reaching 88%. Furthermore, the underlying mechanisms of the penicillin decomposition reaction were investigated by the EPR test and trapping experiment. It was found that the high photocatalytic degradation efficiency was attributed to the heterojunction of CdS-TiO, which successfully suppresses the recombination of the conduction band of CdS and the valence band of TiO. Moreover, it was confirmed that the reaction is the O-consuming process, and introducing O can greatly accelerate the generation of a superoxide radical during the photocatalytic degradation process, which eventually improves the degradation of penicillin and shortens the degradation time. Finally, this work provides the possible penicillin degradation pathways, which will inspire the researchers to explore and design novel photocatalysts in the field of wastewater treatment in the future.
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http://dx.doi.org/10.1021/acsomega.1c02079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8296572PMC
July 2021

Minerals Determined a Special Ecological Niche and Selectively Enriched Microbial Species from Bulk Water Communities in Hot Springs.

Microorganisms 2021 May 10;9(5). Epub 2021 May 10.

State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China.

Minerals provide physical niches and supply nutrients or serve as electron donors/acceptors for microorganism survival and growth, and thus minerals and microbes co-evolved. Yet, little is known about how sediment minerals impact microbial community assembly in hot springs and to what extent mineralogical composition influences microbial community composition and diversity. Here the influences of minerals on thermophiles in Tengchong hot springs were revealed by network analysis of field samples, as well as in-situ microcosm experiments with minerals. A molecular ecological network was constructed based on high throughput sequencing data of 16S rRNA gene, with a combination of water geochemistry and sedimentary mineralogical compositions. Six modules were identified and this highly modular network structure represents the microbial preference to different abiotic factors, consequently resulting in niche partitioning in sedimentary communities in hot springs. Diverse mineralogical compositions generated special niches for microbial species. Subsequently, the in-situ microcosm experiments with four minerals (aragonite, albite, K-feldspar, and quartz) and spring water were conducted in a silicate-hosted alkaline spring (i.e., Gmq) and a carbonate-hosted neutral hot spring (i.e., Gxs) for 70 days. Different microbial preferences were observed among different mineral types (carbonate versus silicate). Aragonite microcosms in Gmq spring enriched archaeal genera Sulfophobococcus and Aeropyrum within the order Desulfurococcales by comparison with both in-situ water and silicate microcosms. Sulfophobococcus was also accumulated in Gxs aragonite microcosms, but the contribution to overall dissimilarity is much lower than that in Gmq spring. Besides, Caldimicrobium was a bacterial genus enriched in Gxs aragonite microcosms, in contrast to in-situ water and silicate microcosms, whereas Candidatus Kryptobacter and Thermus were more abundant in silicate microcosms. The differences in microbial accumulations among different mineral types in the same spring implied that mineral chemistry may exert extra deterministic selective pressure in drawing certain species from the bulk water communities, in addition to stochastic absorption on mineral surface. Taken together, our results highlight the special niche partitioning determined by mineralogical compositions and further confirm that minerals could be used as "fishing bait" to enrich certain rare microbial species.
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http://dx.doi.org/10.3390/microorganisms9051020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8151621PMC
May 2021

Temperature and microbial interactions drive the deterministic assembly processes in sediments of hot springs.

Sci Total Environ 2021 Jun 30;772:145465. Epub 2021 Jan 30.

CAS Key Laboratory for Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences (CAS), Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China.

Terrestrial geothermal ecosystems, as a representative of extreme environments, exhibit a variety of geochemical gradients, and their microbes are thought to be under high stress through environmental selection. However, it is still unclear how stochasticity and biotic interactions contribute to the microbial community assembly in hot springs. Here, we investigated the assembly processes and co-occurrence patterns of microbiota (i.e. bacteria and archaea) in both water and sediments sampled from fifteen hot springs in the Tengchong area, Southwestern of China, using 16S rRNA gene sequencing combined with multivariate ecological and statistical methods. These hot springs harbored more specialists than non-geothermal ecosystems, which are well-adapted to the extreme conditions, as shown by extremely high nearest-taxon index (NTI) and narrower niche width. Habitat differentiation led to the differences in microbial diversity, species-interactions, and community assembly between water and sediment communities. The sediment community showed stronger phylogenetic clustering and was primarily governed by heterogeneous selection, while undominated stochastic processes and dispersal limitation were the major assembly processes in the water community. Temperature and ferrous iron were the major factors mediating the balance of stochastic and deterministic assembly processes in sediment communities, as evidenced by how divergences in temperature and ferrous iron increased the proportion of determinism. Microbial interactions in sediments contributed to deterministic community assembly, as indicated by more complex associations and greater responsiveness to environmental change than water community. These findings uncover the ecological processes underlying microbial communities in hot springs, and provide potential insight into understanding the mechanism to maintain microbial diversity in extreme biospheres.
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http://dx.doi.org/10.1016/j.scitotenv.2021.145465DOI Listing
June 2021

Effects of acute ammonia exposure on antioxidant and detoxification metabolism in clam Cyclina sinensis.

Ecotoxicol Environ Saf 2021 Mar 19;211:111895. Epub 2021 Jan 19.

Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, Jiangsu Province 222005, China.

To investigate the defensive strategies of clam Cyclina sinensis in response to environmental ammonia exposure, we investigate the 96 h median lethal concentration (LC-96 h) and the 96 h safe concentration (SC) of total ammonia nitrogen (TAN) for C. sinensis, and on the basis we examined glutamine synthetase (GS) activity, glutamine content, urea content and the antioxidant enzyme activities of super oxide dismutase (SOD) and catalase (CAT) in 96 h at three different levels of TAN as 0 (control), 73.94 (T1) and 227.04 mg/L (T2). Results showed that LC-96 h and SC for C. sinensis were 65.79 and 6.58 mg/L, respectively. The LC-96 h and SC of NH were 1.70 and 0.17 mg/L, respectively. Ammonia exposure had significantly effects on SOD and CAT activities in the hepatopancreas tissue. Both the level of SOD activity and CAT activity increased with increasing concentration of TAN. No significant differences between T1 and T2 were found in GS activity from 3 h to 96 h after exposed to ammonia, whereas they were significantly higher than those in the control. Both the level of glutamine content in T1 and T2 increased significantly from 6 h to 24 h after exposed to ammonia and they were significantly higher than those in the control. There were no significantly differences were found in the level of urea concentration between T1 and T2 from 6 h to 96 h, while they were significantly higher those in the control. In conclusion, enhancing hepatopancreas antioxidant responses as well as converting ammonia into glutamine and urea worked in combination to allow C. sinensi to defend against acute ammonia exposure.
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http://dx.doi.org/10.1016/j.ecoenv.2021.111895DOI Listing
March 2021

Sampling bias and model choice in continuous phylogeography: Getting lost on a random walk.

PLoS Comput Biol 2021 01 6;17(1):e1008561. Epub 2021 Jan 6.

European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, United Kingdom.

Phylogeographic inference allows reconstruction of past geographical spread of pathogens or living organisms by integrating genetic and geographic data. A popular model in continuous phylogeography-with location data provided in the form of latitude and longitude coordinates-describes spread as a Brownian motion (Brownian Motion Phylogeography, BMP) in continuous space and time, akin to similar models of continuous trait evolution. Here, we show that reconstructions using this model can be strongly affected by sampling biases, such as the lack of sampling from certain areas. As an attempt to reduce the effects of sampling bias on BMP, we consider the addition of sequence-free samples from under-sampled areas. While this approach alleviates the effects of sampling bias, in most scenarios this will not be a viable option due to the need for prior knowledge of an outbreak's spatial distribution. We therefore consider an alternative model, the spatial Λ-Fleming-Viot process (ΛFV), which has recently gained popularity in population genetics. Despite the ΛFV's robustness to sampling biases, we find that the different assumptions of the ΛFV and BMP models result in different applicabilities, with the ΛFV being more appropriate for scenarios of endemic spread, and BMP being more appropriate for recent outbreaks or colonizations.
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http://dx.doi.org/10.1371/journal.pcbi.1008561DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7815209PMC
January 2021

Iron availability is a key factor for freshwater cyanobacterial survival against saline stress.

Environ Res 2021 03 15;194:110592. Epub 2020 Dec 15.

State Key Laboratory of Biogeosciences and Environmental Geology and Institute of Earth Sciences, China University of Geosciences, Beijing, 100083, China. Electronic address:

Estuaries are among the most productive ecosystems and dynamic environments on Earth. Varying salinity is the most important challenge for phytoplankton survival in estuaries. In order to investigate the role of iron nutrition on phytoplankton survival under salinity stress, a freshwater cyanobacterial strain was cultivated in media added with different proportions of seawater (measured with siderophore activities), and supplied with gel-immobilized ferrihydrite as iron source. Results showed that the strain grew well in media with 0% seawater supplied with ferrihydrite as iron source. Surprisingly, the biomasses in media with 50% seawater, with more newly excreted siderophore, were similar to those with 0% seawater, but better than those with 6.25%, 12.5% and 25% seawater. Smaller iron isotopic discriminations between the cyanobacterial cells associated iron and dissolved iron were observed in media with 0% and 50% seawater suggested that higher fractions of iron uptake from aqueous dissolved iron reservoir by these comparatively larger biomasses. In summary, this study proved that iron availability plays a key role in cyanobacterial survival under varying salinity stress, and suggested that siderophores introduced by seawater may accelerate iron dissolution, increase iron availability, and make cyanobacterial cells overcome the adverse effects of high-salinity, and indicated that siderophore excretion is a kind of survival strategy for phytoplankton in face of salinity stress.
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http://dx.doi.org/10.1016/j.envres.2020.110592DOI Listing
March 2021

DSARna: RNA Secondary Structure Alignment Based on Digital Sequence Representation.

Comb Chem High Throughput Screen 2021 ;24(7):1042-1054

College of Life Science, Huaibei Normal University, Huaibei, Anhui, China.

Background: With increasing applications and development of high-throughput sequencing, knowledge of the primary structure of RNA has expanded exponentially. Moreover, the function of RNA is determined by the secondary or higher RNA structure, and similar structures are related to similar functions, such as the secondary clover structure of tRNA. Therefore, RNA structure alignment is an important subject in computational biology and bioinformatics to predict function accurately. However, the traditional RNA structure alignment algorithms have some drawbacks such as high complexity and easy loss of secondary structure information.

Objective: To study R,,NA secondary structure alignment according to the shortcomings of existing secondary structure alignment algorithms and the characteristics of RNA secondary structure.

Methods: We propose a new digital sequence RNA structure representation algorithm named "DSARna". Then based on a dynamic programming algorithm, the scoring matrix and binary path matrix are simultaneously constructed. The backtracking path is identified in the path matrix, and the optimal result is predicted according to the path length.

Conclusions: Upon comparison with the existing SimTree algorithm through experimental analysis, the proposed method showed higher accuracy and could ensure that the structural information is not easily lost in terms of improved specificity, sensitivity, and the Matthews correlation coefficient.
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http://dx.doi.org/10.2174/1386207323666200811100338DOI Listing
January 2021

The complete mitochondrial genome of (Lepidoptera: Erebidae) and phylogenetic relationships within Noctuoidea.

PeerJ 2020 16;8:e8780. Epub 2020 Mar 16.

College of Life Sciences, Huaibei Normal University, Huaibei, Anhui, China.

To determine the mitochondrial genome (mitogenome) structure and to clarify its phylogenetic position, the entire mitogenome of was sequenced and annotated. The mitogenome is 15,721 bp in size and contains 37 genes (protein-coding genes, transfer RNA genes, ribosomal RNA genes) usually found in lepidopteran mitogenomes. The newly sequenced mitogenome contained some common features reported in other Erebidae species, e.g., an A+T biased nucleotide composition and a non-canonical start codon for (CGA). Like other insect mitogenomes, the mitogenome had a conserved sequence 'ATACTAA' in an intergenic spacer between and , and a motif 'ATAGA' followed by a 20 bp poly-T stretch in the A+T rich region. Phylogenetic analyses supported as part of the Erebidae family and reconfirmed the monophyly of the subfamilies Arctiinae, Catocalinae and Lymantriinae within Erebidae.
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http://dx.doi.org/10.7717/peerj.8780DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7081777PMC
March 2020

Characterization of the complete mitochondrial genome of Orthaga olivacea Warre (Lepidoptera Pyralidae) and comparison with other Lepidopteran insects.

PLoS One 2020 6;15(3):e0227831. Epub 2020 Mar 6.

School of Life Sciences, Anhui Agricultural University, Hefei, P. R. China.

Orthaga olivacea Warre (Lepidoptera: Pyralidae) is an important agricultural pest of camphor trees (Cinnamomum camphora). To further supplement the known genome-level features of related species, the complete mitochondrial genome of Orthaga olivacea is amplified, sequenced, annotated, analyzed, and compared with 58 other species of Lepidopteran. The complete sequence is 15,174 bp, containing 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes, and a putative control region. Base composition is biased toward adenine and thymine (79.02% A+T) and A+T skew are slightly negative. Twelve of the 13 PCGs use typical ATN start codons. The exception is cytochrome oxidase 1 (cox1) that utilizes a CGA initiation codon. Nine PCGs have standard termination codon (TAA); others have incomplete stop codons, a single T or TA nucleotide. All the tRNA genes have the typical clover-leaf secondary structure, except for trnS(AGN), in which dihydrouridine (DHU) arm fails to form a stable stem-loop structure. The A+T-rich region (293 bp) contains a typical Lepidopter motifs 'ATAGA' followed by a 17 bp poly-T stretch, and a microsatellite-like (AT)13 repeat. Codon usage analysis revealed that Asn, Ile, Leu2, Lys, Tyr and Phe were the most frequently used amino acids, while Cys was the least utilized. Phylogenetic analysis suggested that among sequenced lepidopteran mitochondrial genomes, Orthaga olivacea Warre was most closely related to Hypsopygia regina, and confirmed that Orthaga olivacea Warre belongs to the Pyralidae family.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0227831PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7059908PMC
May 2020

Knockdown of YAP inhibits growth in Hep-2 laryngeal cancer cells via epithelial-mesenchymal transition and the Wnt/β-catenin pathway.

BMC Cancer 2019 Jul 3;19(1):654. Epub 2019 Jul 3.

Department of Otolaryngology-Head and Neck Surgery, The Provincial Hospital affiliated to Anhui Medical University, Hefei, Anhui, People's Republic of China.

Background: Yes-associated protein (YAP) plays a crucial role in tumour development and it is the main effector of the Hippo signalling pathway. However, the mechanism underlying YAP downregulation in laryngeal cancer is still unclear. In our previous study, we found that YAP, compared with adjacent tissues, was expressed higher in laryngeal cancer and was also closely associated with histological differentiation, TNM stage and poor prognosis.

Methods: In this study, we attempted to determine whether silenced YAP could downregulate human laryngeal carcinoma Hep-2 cells progression. YAP was downregulated in Hep-2 cells by shRNA, and the malignant ability of Hep-2 was assessed in vitro and in vivo.

Results: In vitro, CCK-8, colony formation and wound healing assays showed that downregulation of YAP significantly reduced the rates of proliferation, migration, and invasion in Hep-2 cells. Downregulation of YAP distinctly induced G2/M cycle arrest and increased the rate of apoptosis. Accordingly, western blot assay suggested that the expression of DKK1, vimentin and β-catenin was significantly decreased after YAP downregulated treatment, thereby indicating that YAP mediated the EMT programme and the Wnt/β-catenin signalling pathway in carcinoma of the larynx. Furthermore, silencing of YAP suppressed Hep-2 cell tumourigenesis and metastasis in vivo.

Conclusion: In summary, our findings demonstrated the proliferation of YAP downregulation and the invasion of Hep-2 cells via downregulating the Wnt/β-catenin pathway in vitro and in vivo, suggesting that YAP may provide a potential therapeutic strategy for the treatment of laryngeal cancer.
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http://dx.doi.org/10.1186/s12885-019-5832-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6610877PMC
July 2019

Immune function of a Rab-related protein by modulating the JAK-STAT signaling pathway in the silkworm, Bombyx mori.

Arch Insect Biochem Physiol 2018 Jan 30;97(1). Epub 2017 Nov 30.

College of Life Science, Anhui Agricultural University, Hefei, China.

The Rab-family GTPases mainly regulate intracellular vesicle transport, and play important roles in the innate immune response in invertebrates. However, the function and signal transduction of Rab proteins in immune reactions remain unclear in silkworms. In this study, we analyzed a Rab-related protein of silkworm Bombyx mori (BmRABRP) by raising antibodies against its bacterially expressed recombinant form. Tissue distribution analysis showed that BmRABRP mRNA and protein were high expressed in the Malpighian tubule and fat body, respectively. However, among the different stages, only the fourth instar larvae and pupae showed significant BmRABRP levels. After challenge with four pathogenic microorganisms (Escherichia coli, BmNPV, Beauveria bassiana, Micrococcus luteus), the expression of BmRABRP mRNA in the fat body was significantly upregulated. In contrast, the BmRABRP protein was significantly upregulated after infection with BmNPV, while it was downregulated by E. coli, B. bassiana, and M. luteus. A specific dsRNA was used to explore the immune function and relationship between BmRABRP and the JAK-STAT signaling pathway. After BmRABRP gene interference, significant reduction in the number of nodules and increased mortality suggested that BmRABRP plays an important role in silkworm's response to bacterial challenge. In addition, four key genes (BmHOP, BmSTAT, BmSOCS2, and BmSOCS6) of the JAK-STAT signaling pathway showed significantly altered expressions after BmRABRP silencing. BmHOP and BmSOCS6 expressions were significantly decreased, while BmSTAT and BmSOCS2 were significantly upregulated. Our results suggested that BmRABRP is involved in the innate immune response against pathogenic microorganisms through the JAK-STAT signaling pathway in silkworm.
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http://dx.doi.org/10.1002/arch.21434DOI Listing
January 2018

Identification and function of cAMP response element binding protein in Oak silkworm Antheraea pernyi.

J Invertebr Pathol 2018 01 24;151:14-20. Epub 2017 Oct 24.

College of Life Sciences, Anhui Agricultural University, 130 Changjiang West Road, Hefei 230036, China. Electronic address:

Cyclic AMP response element binding (CREB) proteins participate in the regulation of many biological processes. However, little is known about their role in immune regulation in the Oak silkworm (Antheraea pernyi). In this study, a CREB gene was identified in A. pernyi and its role in immune regulation was investigated. ApCREB shares conserved signature motifs with other CREB proteins, and includes a typical leucine zipper domain, specific DNA-binding site, nuclear localisation signal (NLS) and cAMP-dependent protein kinase phosphorylation site. Recombinant ApCREB was expressed in Escherichia coli and used to raise rabbit anti-ApCREB polyclonal antibodies. ApCREB mRNA was detected in all examined tissues, with maximum expression in the midgut and integument. Following exposure to four pathogenic microorganisms (Beauveria bassiana, Escherichia coli, Micrococcus luteus, and Antheraea pernyi nuclear polyhedrosis virus), expression of ApCREB was up-regulated by B. bassiana, E. coli and ApNPV, down-regulated by M. luteus. RNA interference of ApCREB affected mRNA expression levels of antimicrobial peptide genes attacin-1, cecropin B, defensin-1, gloverin, and lebocin-2. These findings demonstrate that ApCREB is a CREB homologue that may be involved in innate immunity in A. pernyi.
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http://dx.doi.org/10.1016/j.jip.2017.10.006DOI Listing
January 2018

Characterization and function of a novel calmodulin-like protein from crayfish Procambarus clarkii.

Fish Shellfish Immunol 2017 Aug;67:518-522

College of Life Sciences, Anhui Agricultural University, Hefei 230036, China.

Calmodulin plays an important role in calcium-dependent signal transduction pathways. In this experiment, a novel calmodulin-like gene (Pc-CaM-L) was identified in the crayfish Procambarus clarkii; it encodes a polypeptide of 145 amino acids. Quantitative real-time PCR analysis revealed that Pc-CaM-L was expressed in all examined tissues, including hepatopancreas, hemocytes, heart, gill, intestine and muscle; the highest Pc-CaM-L expression level was detected in the hepatopancreas. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot analysis demonstrated that a recombinant Pc-CaM-L protein was successfully expressed in Escherichia coli. The calcium-binding activity of the purified Pc-CaM-L protein was confirmed by gel mobility shift assay. The expression of Pc-CaM-L was significantly upregulated in gut, gill and hemocytes after lipopolysaccharide or polyinosinic:polycytidylic acid induction. These results suggest that Pc-CaM-L plays a role in the immune response of P. clarkii.
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http://dx.doi.org/10.1016/j.fsi.2017.06.005DOI Listing
August 2017

Serpin-14 negatively regulates prophenoloxidase activation and expression of antimicrobial peptides in Chinese oak silkworm Antheraea pernyi.

Dev Comp Immunol 2017 11 22;76:45-55. Epub 2017 May 22.

College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China. Electronic address:

Genes encoding proteins of serpins superfamily are widely distributed in invertebrates. In insects, serpins play important roles in regulating immune responses and other physiological processes. Here, we report the cloning and characterization of cDNA of Apserpin-14 from Chinese oak silkworm (Antheraea pernyi). The Apserpin-14 gene contains 1206 bp open reading frame, encoding a predicted 401 amino acid residue protein. We expressed the recombinant Apserpin-14 protein in Escherichia coli and then purified protein was used to prepare rabbit anti-Apserpin-14 polyclonal antibodies. Quantitative real-time PCR analysis revealed that mRNA level of Apserpin-14 was highest in the fat body, whereas, among developmental stages the 5th instar and pupal stage showed greatest expression. Furthermore, Escherichia coli, Beauveria bassiana, Micrococcus luteus and nuclear polyhedrosis virus challenge enhanced Apserpin-14 transcript in both the fat body and hemocyte. Recombinant Apserpin-14 added to hemolymph inhibited spontaneous melanization and suppressed prophenoloxidase activation stimulated by M. luteus, but did not affect phenoloxidase (PO) activity. Injection of recombinant Apserpin-14 protein into A. pernyi larvae significantly reduced the transcript levels of antimicrobial peptides in the fat body, while its depletion by double stranded RNA enhanced their expression. We concluded that Apserpin-14 likely involved in regulation of proPO activation and production of antimicrobial peptides, implying its important role in the innate immune system of A. pernyi.
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http://dx.doi.org/10.1016/j.dci.2017.05.017DOI Listing
November 2017

Gene expression patterns in response to pathogen challenge and interaction with hemolin suggest that the Yippee protein of Antheraea pernyi is involved in the innate immune response.

J Invertebr Pathol 2016 07 31;138:10-7. Epub 2016 May 31.

College of Life Sciences, Anhui Agricultural University, Hefei 230036, China. Electronic address:

Yippee was first identified as a protein that physically interacts with the Hemolin protein of Hyalophora cecropia. In this study, we identified a gene with a 366bp open reading frame (ORF) that encodes a 121 amino acid protein containing a conserved Yippee domain. We named this gene Ap-Yippee (Yippee gene from Antheraea pernyi), and investigated the role of the protein in the host immune response. A recombinant Ap-Yippee protein was expressed in Escherichia coli cells, and polyclonal antibodies were produced against the recombinant protein. Real-time PCR and a Western blot analysis revealed that Ap-Yippee is expressed in the hemocytes, Malpighian tubules, midgut, silk gland, epidermis, and fat bodies of A. pernyi, with the highest expression level observed in Malpighian tubules. The fifth instar larvae of A. pernyi were challenged by injecting them with nucleopolyhedrovirus (AP-NPV), the Gram-negative bacterium E. coli, the Gram-positive bacterium Micrococcus luteus, or the entomopathogenic fungus, Beauveria bassiana. These challenges with diverse pathogens resulted in differential expression patterns of the protein. A knockdown of the Ap-Yippee gene by small interfering RNA (siRNA) transfection had a significant influence on the expression of the hemolin in the pupae which was confirmed by qRT-PCR and Western blot. Furthermore, a possible protein-protein interaction between Ap-Yippee and Hemolin was explored by Far-Western blotting. Therefore, our data suggest that the Ap-Yippee protein is involved in a pathway that regulates the immune response of insects.
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http://dx.doi.org/10.1016/j.jip.2016.05.010DOI Listing
July 2016
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