bluuebunny/crossref_metadata_2025 huggingface dataset:
CT Image Reconstruction via Nonlocal Low-Rank Regularization and Data-Driven Tight Frame
Authors: Shen Yanfeng , Sun Shuli , Xu Fengsheng , Liu Yanqin , Yin Xiuling , Zhou Xiaoshuang
Published: October 2021

X-ray computed tomography (CT) is widely used in medical applications, where many efforts have been made for decades to eliminate artifacts caused by incomplete projection. In this paper, we propose a new CT image reconstruction model based on nonlocal low-rank regularity and data-driven tight frame (NLR-DDTF). Unlike the Spatial-Radon domain data-driven tight frame regularization, the proposed NLR-DDTF model uses an asymmetric treatment for image reconstruction and Radon domain inpainting, which combines the nonlocal low-rank approximation method for spatial domain CT image reconstruction and data-driven tight frame-based regularization for Radon domain image inpainting. An alternative direction minimization algorithm is designed to solve the proposed model. Several numerical experiments and comparisons are provided to illustrate the superior performance of the NLR-DDTF method.
Hyperspectral Image Classification Based on Cross-Scene Adaptive Learning
Authors: Wang Aili , Liu Chengyang , Xue Dong , Wu Haibin , Zhang Yuxiao , Liu Meihong
Published: October 2021

Aiming at few-shot classification in the field of hyperspectral remote sensing images, this paper proposes a classification method based on cross-scene adaptive learning. First, based on the unsupervised domain adaptive technology, cross-scene knowledge transfer learning is carried out to reduce the differences between source scene and target scene. At the same time, depthwise over-parameterized convolution is used in the deep embedding model to improve the convergence speed and feature extraction ability. Second, two symmetrical subnetworks are designed in the model to further reduce the differences between source scene and target scene. Then, Manhattan distance is learned in the Manhattan metric space in order to reduce the computational cost of the model. Finally, the weighted K-nearest neighbor is introduced for classification, in which the weighted Manhattan metric distance is assigned to the clustered samples to improve the processing ability to the imbalanced hyperspectral image data. The effectiveness of the proposed algorithm is verified on the Pavia and Indiana hyperspectral dataset. The overall classification accuracy is 90.90% and 65.01%. Compared with six other kinds of hyperspectral image classification methods, the proposed cross-scene method has better classification accuracy.
A New Constructive Method for Solving the Schrödinger Equation
Authors: Rajchel Kazimierz
Published: October 2021

In this paper, a new method for the exact solution of the stationary, one-dimensional Schrödinger equation is proposed. Application of the method leads to a three-parametric family of exact solutions, previously known only in the limiting cases. The method is based on solutions of the Ricatti equation in the form of a quadratic function with three parameters. The logarithmic derivative of the wave function transforms the Schrödinger equation to the Ricatti equation with arbitrary potential. The Ricatti equation is solved by exploiting the particular symmetry, where a family of discrete transformations preserves the original form of the equation. The method is applied to a one-dimensional Schrödinger equation with a bound states spectrum. By extending the results of the Ricatti equation to the Schrödinger equation the three-parametric solutions for wave functions and energy spectrum are obtained. This three-parametric family of exact solutions is defined on compact support, as well as on the whole real axis in the limiting case, and corresponds to a uniquely defined form of potential. Celebrated exactly solvable cases of special potentials like harmonic oscillator potential, Coulomb potential, infinite square well potential with corresponding energy spectrum and wave functions follow from the general form by appropriate selection of parameters values. The first two of these potentials with corresponding solutions, which are defined on the whole axis and half axis respectively, are achieved by taking the limit of general three-parametric solutions, where one of the parameters approaches a certain, well-defined value.
Qualitative Theory of Two-Dimensional Polynomial Dynamical Systems
Authors: Shestopalov Yury , Shakhverdiev Azizaga
Published: October 2021

A qualitative theory of two-dimensional quadratic-polynomial integrable dynamical systems (DSs) is constructed on the basis of a discriminant criterion elaborated in the paper. This criterion enables one to pick up a single parameter that makes it possible to identify all feasible solution classes as well as the DS critical and singular points and solutions. The integrability of the considered DS family is established. Nine specific solution classes are identified. In each class, clear types of symmetry are determined and visualized and it is discussed how transformations between the solution classes create new types of symmetries. Visualization is performed as series of phase portraits revealing all possible catastrophic scenarios that result from the transition between the solution classes.
Through a Glass Darkly—Some Thoughts on Symmetry and Chemistry
Authors: Constable Edwin C.
Published: October 2021

This article reviews the development of concepts of chirality in chemistry. The story follows the parallel development of the optical properties of materials and the understanding of chemical structure until the two are fused in the recognition of the tetrahedral carbon atom in 1874. The different types of chiral molecule that have been identified since the first concept of the asymmetric carbon atom are introduced as is the notation used in various disciplines of chemistry to describe the relative or absolute configuration. In the final section, a polemical case for a unified nomenclature is presented.
Analysis and Suppression of Voltage Violation and Fluctuation with Distributed Photovoltaic Integration
Authors: Li Yahui , Sun Yuanyuan , Li Kejun , Zhuang Jingru , Liang Yongliang , Pang Yanqing
Published: October 2021

In recent years, the violation and fluctuation of system voltage has occurred with greater frequency with the integration of high-penetration distributed photovoltaic generation. In this paper, the voltage violation and fluctuation in a high-penetration distributed photovoltaic integrated system is analyzed, and then a corresponding suppression strategy is proposed. Firstly, based on solar cell and photovoltaic control system models, the influence factors of photovoltaic output are analyzed. Secondly, the voltage violation and fluctuation caused by photovoltaic integration is analyzed, and the quadratic parabola relationship between bus voltage fluctuation and photovoltaic power variation is constructed. Next, according to the virtual synchronous generator characteristic of distributed photovoltaics, a double-hierarchical suppression strategy is proposed to make full use of reactive power regulation capability, which can maintain the symmetry of power supply while meeting standard requirements. The proposed strategy can conveniently realize quick response and support the photovoltaic extensive access. Moreover, with the employment of the proposal, the system voltage violation and fluctuation can be suppressed effectively. Finally, considering the photovoltaic access location, capacity, and partial shading, the effectiveness of the proposed strategy is verified in IEEE 33-bus distribution system with field measured data. After distributed photovoltaic accesses the system, more than 60% of buses appear to have undergone bus voltage violation. With the proposed method, more than 20% of the voltage deviation and more than 6% of the voltage fluctuation are effectively suppressed so that the system voltage can be kept below 1.07 p.u. and the voltage fluctuation can be kept within 4%, meeting the requirements of power quality standards.
Analysis on ψ-Hilfer Fractional Impulsive Differential Equations
Authors: Karthikeyan Kulandhaivel , Karthikeyan Panjaiyan , Chalishajar Dimplekumar N. , Raja Duraisamy Senthil , Sundararajan Ponnusamy
Published: October 2021

In this manuscript, we establish the existence of results of fractional impulsive differential equations involving ψ-Hilfer fractional derivative and almost sectorial operators using Schauder fixed-point theorem. We discuss two cases, if the associated semigroup is compact and noncompact, respectively. We consider here the higher-dimensional system of integral equations. We present herewith new theoretical results, structural investigations, and new models and approaches. Some special cases of the results are discussed as well. Due to the nature of measurement of noncompactness theory, there exists a strong relationship between the sectorial operator and symmetry. When working on either of the concepts, it can be applied to the other one as well. Finally, a case study is presented to demonstrate the major theory.
Measure of Departure from Conditional Symmetry Based on Cumulative Probabilities for Square Contingency Tables
Authors: Saigusa Yusuke , Teramoto Yuta , Tomizawa Sadao
Published: October 2021

For the analysis of square contingency tables with ordered categories, a measure was developed to represent the degree of departure from the conditional symmetry model in which there is an asymmetric structure of the cell probabilities with respect to the main diagonal of the table. The present paper proposes a novel measure for the departure from conditional symmetry based on the cumulative probabilities from the corners of the square table. In a given example, the proposed measure is applied to Japanese occupational status data, and the interpretation of the proposed measure is illustrated as the departure from a proportional structure of social mobility.
Classification of Integrodifferential C∗-Algebras
Authors: Kutsenko Anton A.
Published: October 2021

The infinite product of matrices with integer entries, known as a modified Glimm–Bratteli symbol n, is a new, sufficiently simple, and very powerful tool for the characterization of approximately finite-dimensional (AF) algebras. This symbol provides a convenient algebraic representation of the Bratteli diagram for AF algebras in the same way as was previously performed by J. Glimm for more simple uniformly hyperfinite (UHF) algebras. We apply this symbol to characterize integrodifferential algebras. The integrodifferential algebra FN,M is the C∗-algebra generated by the following operators acting on L2([0,1)N→CM): (1) operators of multiplication by bounded matrix-valued functions, (2) finite-difference operators, and (3) integral operators. Most of the operators and their approximations studying in physics belong to these algebras. We give a complete characterization of FN,M. In particular, we show that FN,M does not depend on M, but depends on N. At the same time, it is known that differential algebras HN,M, generated by the operators (1) and (2) only, do not depend on both dimensions N and M; they are all ∗-isomorphic to the universal UHF algebra. We explicitly compute the Glimm–Bratteli symbols (for HN,M, it was already computed earlier) which completely characterize the corresponding AF algebras. This symbol n is an infinite product of matrices with nonnegative integer entries. Roughly speaking, all the symmetries appearing in the approximation of complex infinite-dimensional integrodifferential and differential algebras by finite-dimensional ones are coded by a product of integer matrices.
Multi-Controller Load Balancing Algorithm for Test Network Based on IACO
Authors: Fu Yanfang , Zhu Yuting , Cao Zijian , Du Zhiqiang , Yan Guochuang , Du Jiang
Published: October 2021

With the rapid increase of volume and complexity in the projectile flight test business, it is becoming increasingly important to improve the quality of the service and efficiency of multi-domain cooperative networks. The key for these improvements is to solve the problem of asymmetric load of multi-controllers in multi-domain networks. However, due to the current reality, it is difficult to meet the demands of future tests, and there is not guarantee of subnet multi-domain test load balancing. Most recent works have used a heuristic approach to seek the optimal dynamic migration path, but they may fall into the local optimum. This paper proposes an improved ant colony algorithm (IACO) that can transform the modeling of the mapping relationship between the switch and the controller into a traveling salesman problem by combining the ant colony algorithm and artificial fish swarm algorithm. The IACO not only ensures the load balancing of multi-controllers but also improves the reliability of the cluster. The simulation results show that compared to other algorithms such as traditional ant colony algorithms and distributed decision mechanisms, this IACO achieves better load balancing, improves the average throughput of multi-controller clusters, and effectively reduces the response time of controller request events.
An Optimization Model of Integrated AGVs Scheduling and Container Storage Problems for Automated Container Terminal Considering Uncertainty
Authors: Jian Wentao , Zhu Jishuang , Zeng Qingcheng
Published: October 2021

The running path of automated guided vehicles (AGVs) in the automated terminal is affected by the storage location of containers and the running time caused by congestion, deadlock and other problems during the driving process is uncertain. In this paper, considering the different AGVs congestion conditions along the path, a symmetric triangular fuzzy number is used to describe the AGVs operation time distribution and a multi-objective scheduling optimization model is established to minimize the risk of quay cranes (QCs) delay and the shortest AGVs operation time. An improved genetic algorithm was designed to verify the effectiveness of the model and algorithm by comparing the results of the AGVs scheduling and container storage optimization model based on fixed congestion coefficient under different example sizes. The results show that considering the AGVs task allocation and container storage location allocation optimization scheme with uncertain running time can reduce the delay risk of QCs, reduce the maximum completion time and have important significance for improving the loading and unloading efficiency of the automated terminal.
Using Rough Set Theory to Find Minimal Log with Rule Generation
Authors: Alawneh Tahani Nawaf , Tut Mehmet Ali
Published: October 2021

Data pre-processing is a major difficulty in the knowledge discovery process, especially feature selection on a large amount of data. In literature, various approaches have been suggested to overcome this difficulty. Unlike most approaches, Rough Set Theory (RST) can discover data de-pendency and reduce the attributes without the need for further information. In RST, the discernibility matrix is the mathematical foundation for computing such reducts. Although it proved its efficiency in feature selection, unfortunately it is computationally expensive on high dimensional data. Algorithm complexity is related to the search of the minimal subset of attributes, which requires computing an exponential number of possible subsets. To overcome this limitation, many RST enhancements have been proposed. Contrary to recent methods, this paper implements RST concepts in an iterated manner using R language. First, the dataset was partitioned into a smaller number of subsets and each subset processed independently to generate its own minimal attribute set. Within the iterations, only minimal elements in the discernibility matrix were considered. Finally, the iterated outputs were compared, and those common among all reducts formed the minimal one (Core attributes). A comparison with another novel proposed algorithm using three benchmark datasets was performed. The proposed approach showed its efficiency in calculating the same minimal attribute sets with less execution time.
Digital Technologies and Open Data Sources in Marine Biotoxins’ Risk Analysis: The Case of Ciguatera Fish Poisoning
Authors: Katikou Panagiota
Published: October 2021

Currently, digital technologies influence information dissemination in all business sectors, with great emphasis put on exploitation strategies. Public administrations often use information systems and establish open data repositories, primarily supporting their operation but also serving as data providers, facilitating decision-making. As such, risk analysis in the public health sector, including food safety authorities, often relies on digital technologies and open data sources. Global food safety challenges include marine biotoxins (MBs), being contaminants whose mitigation largely depends on risk analysis. Ciguatera Fish Poisoning (CFP), in particular, is a MB-related seafood intoxication attributed to the consumption of fish species that are prone to accumulate ciguatoxins. Historically, CFP occurred endemically in tropical/subtropical areas, but has gradually emerged in temperate regions, including European waters, necessitating official policy adoption to manage the potential risks. Researchers and policy-makers highlight scientific data inadequacy, under-reporting of outbreaks and information source fragmentation as major obstacles in developing CFP mitigation strategies. Although digital technologies and open data sources provide exploitable scientific information for MB risk analysis, their utilization in counteracting CFP-related hazards has not been addressed to date. This work thus attempts to answer the question, “What is the current extent of digital technologies’ and open data sources’ utilization within risk analysis tasks in the MBs field, particularly on CFP?”, by conducting a systematic literature review of the available scientific and grey literature. Results indicate that the use of digital technologies and open data sources in CFP is not negligible. However, certain gaps are identified regarding discrepancies in terminology, source fragmentation and a redundancy and downplay of social media utilization, in turn constituting a future research agenda for this under-researched topic.
EGCG Alleviates Oxidative Stress and Inhibits Aflatoxin B1 Biosynthesis via MAPK Signaling Pathway
Authors: Xu Dan , Peng Shurui , Guo Rui , Yao Lishan , Mo Haizhen , Li Hongbo , Song Hongxin , Hu Liangbin
Published: October 2021

Aflatoxin biosynthesis has established a connection with oxidative stress, suggesting a prevention strategy for aflatoxin contamination via reactive oxygen species (ROS) removal. Epigallocatechin gallate (EGCG) is one of the most active and the richest molecules in green tea with well-known antioxidant effects. Here, we found EGCG could inhibit aflatoxin B1 (AFB1) biosynthesis without affecting mycelial growth in Aspergillus flavus, and the arrest occurred before the synthesis of toxin intermediate metabolites. Further RNA-seq analysis indicated that multiple genes involved in AFB1 biosynthesis were down-regulated. In addition, EGCG exposure facilitated the significantly decreased expression of AtfA which is a bZIP (basic leucine zipper) transcription factor mediating oxidative stress. Notably, KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis indicated that the MAPK signaling pathway target transcription factor was down-regulated by 1 mg/mL EGCG. Further Western blot analysis showed 1 mg/mL EGCG could decrease the levels of phosphorylated SakA in both the cytoplasm and nucleus. Taken together, these data evidently supported that EGCG inhibited AFB1 biosynthesis and alleviated oxidative stress via MAPK signaling pathway. Finally, we evaluated AFB1 contamination in soy sauce fermentation and found that EGCG could completely control AFB1 contamination at 8 mg/mL. Conclusively, our results supported the potential use of EGCG as a natural agent to prevent AFB1 contamination in fermentation industry.
In Vitro Assay of Translation Inhibition by Trichothecenes Using a Commercially Available System
Authors: Toyotome Takahito , Kamei Katsuhiko
Published: October 2021

Trichothecenes are a family of major secondary metabolites produced by some common filamentous fungi, including plant pathogenic and entomopathogenic fungi. It may be considered difficult to conduct a comparison between the toxicities of trichothecenes with consideration of different conditions and cell lines. In the current study, we developed an in vitro assay based on a commercially available system to estimate the translation inhibition, that is, the main toxicity, of trichothecenes. The assay was applied to estimate the inhibition of protein synthesis by trichothecenes. Initially, we examined the assay using trichothecene dissolved in water followed by an assessment of trichothecene solutions dissolved in acetonitrile. The obtained data showed that the assay tolerated the small amount of acetonitrile. The assay examined in this study has the advantages of a short operation time (one day), ease of use, and data stability, as it is a non-cell-based assay whose components are commercially available. It is expected that this assay will contribute to the evaluation of the toxicity of a vast number of trichothecenes.
BMAA, Methylmercury, and Mechanisms of Neurodegeneration in Dolphins: A Natural Model of Toxin Exposure
Authors: Davis David A. , Garamszegi Susanna P. , Banack Sandra Anne , Dooley Patrick D. , Coyne Thomas M. , McLean Dylan W. , Rotstein David S. , Mash Deborah C. , Cox Paul Alan
Published: October 2021

Dolphins are well-regarded sentinels for toxin exposure and can bioaccumulate a cyanotoxin called β-N-methylamino-l-alanine (BMAA) that has been linked to human neurodegenerative disease. The same dolphins also possessed hallmarks of Alzheimer’s disease (AD), suggesting a possible association between toxin exposure and neuropathology. However, the mechanisms of neurodegeneration in dolphins and the impact cyanotoxins have on these processes are unknown. Here, we evaluate BMAA exposure by investigating transcription signatures using PCR for dolphin genes homologous to those implicated in AD and related dementias: APP, PSEN1, PSEN2, MAPT, GRN, TARDBP, and C9orf72. Immunohistochemistry and Sevier Münger silver staining were used to validate neuropathology. Methylmercury (MeHg), a synergistic neurotoxicant with BMAA, was also measured using PT-GC-AFS. We report that dolphins have up to a three-fold increase in gene transcription related to Aβ+ plaques, neurofibrillary tangles, neuritic plaques, and TDP-43+ intracytoplasmic inclusions. The upregulation of gene transcription in our dolphin cohort paralleled increasing BMAA concentration. In addition, dolphins with BMAA exposures equivalent to those reported in AD patients displayed up to a 14-fold increase in AD-type neuropathology. MeHg was detected (0.16–0.41 μg/g) and toxicity associated with exposure was also observed in the brain. These results demonstrate that dolphins develop neuropathology associated with AD and exposure to BMAA and MeHg may augment these processes.
Effect of Lactic Acid Bacteria on the Fermentation Quality and Mycotoxins Concentrations of Corn Silage Infested with Mycotoxigenic Fungi
Authors: Li Jinyang , Wang Wenbo , Chen Sifan , Shao Tao , Tao Xuxiong , Yuan Xianjun
Published: October 2021

This study was conducted to evaluate the effect of lactic acid bacteria (LAB) on fermentation quality, mycotoxin concentrations, and microbial communities of whole-crop corn silages infested with mycotoxigenic fungi. Cultured spores (106 cfu/mL) of mycotoxigenic Aspergillus flavus and Fusarium graminearum were sprayed (5 mL) on corn forage on 27 July and 10 August 2018. On 21 August 2018, sprayed (FI; 3 plots) and unsprayed (NFI; 3 plots) corn forage were harvested at the 1/2 kernel milk line stage, followed by chopping and ensiling without inoculants (CON), or with Lactobacillus buchneri (LB, 1 × 106 cfu/g FW), Lactobacillus plantarum (LT, 1 × 106 cfu/g FW), or L. buchneri + L. plantarum (BT: both L. buchneri and L. plantarum applied at 0.5 × 106 cfu/g FW). After 90 d of ensiling, FI silages had a higher (p < 0.05) pH value and higher acetic acid (ACA), ethanol, and ammonia nitrogen (ammonia N) concentrations, but lower (p < 0.05) lactic acid (LA) concentrations than NFI silage. The inoculants decreased pH and increased LA concentration and LA/ACA compared with CON. The aflatoxin B1 (AFB1) was only detected in FI fresh corn and silages; ensiling decreased (p < 0.05) AFB1 concentration compared with fresh corn, and LB and BT decreased AFB1 concentration compared with CON. The zearalenone (ZEN), deoxynivalenol (DON), and fumonisin B1 (FB1) concentrations were similar (p < 0.05) for NFI silages, while ZEN concentration in BT was the lowest (p < 0.05) among all FI silages; DON and FB1 concentrations in LB, LT, and BT silages were significantly lower (p < 0.05) than those of CON in FI silages. The fungal infestation increased the bacterial and fungal diversity of silages compared with NFI silages. The FI silages had a higher relative abundance (RA) of Lactobacillus, Weissella, Wickerhamomyces, Pichia, and Epicoccum than the corresponding NFI silages. The RA of Aspergillus and Fusarium markedly decreased after 90 d of ensiling, and the inoculation expanded this trend irrespective of fungal infestation. The Penicillium in FI silages survived after 90 d of ensiling, while the inoculants decreased the RA of Penicillium. Inoculants mitigate the adverse effects of fungal infestation on corn silage quality by changing the bacterial and fungal communities.
Cyclophilin D Promotes Acute, but Not Chronic, Kidney Injury in a Mouse Model of Aristolochic Acid Toxicity
Authors: Leong Khai Gene , Ozols Elyce , Kanellis John , Ma Frank Y. , Nikolic-Paterson David J.
Published: October 2021

The plant-derived toxin, aristolochic acid (AA), is the cause of Chinese Herb Nephropathy and Balkan Nephropathy. Ingestion of high dose AA induces acute kidney injury, while chronic low dose ingestion leads to progressive kidney disease. Ingested AA is taken up by tubular epithelial cells of the kidney, leading to DNA damage and cell death. Cyclophilin D (CypD) participates in mitochondrial-dependent cell death, but whether this mechanism operates in acute or chronic AA-induced kidney injury is unknown. We addressed this question by exposing CypD-/- and wild type (WT) mice to acute high dose, or chronic low dose, AA. Administration of 5 mg/kg AA to WT mice induced acute kidney injury 3 days later, characterised by loss of kidney function, tubular cell damage and death, and neutrophil infiltration. All of these parameters were significantly reduced in CypD-/- mice. Chronic low dose (2 mg/kg AA) administration in WT mice resulted in chronic kidney disease with impaired renal function and renal fibrosis by day 28. However, CypD-/- mice were not protected from AA-induced chronic kidney disease. In conclusion, CypD facilitates AA-induced acute kidney damage, but CypD does not contribute to the transition of acute kidney injury to chronic kidney disease during ongoing AA exposure.
Full Neutralization of Centruroides sculpturatus Scorpion Venom by Combining Two Human Antibody Fragments
Authors: Riaño-Umbarila Lidia , Romero-Moreno José Alberto , Ledezma-Candanoza Luis M. , Olamendi-Portugal Timoteo , Possani Lourival D. , Becerril Baltazar
Published: October 2021

A fundamental issue of the characterization of single-chain variable fragments (scFvs), capable of neutralizing scorpion toxins, is their cross-neutralizing ability. This aspect is very important in Mexico because all scorpions dangerous to humans belong to the Centruroides genus, where toxin sequences show high identity. Among toxin-neutralizing antibodies that were generated in a previous study, scFv 10FG2 showed a broad cross-reactivity against several Centruroides toxins, while the one of scFv LR is more limited. Both neutralizing scFvs recognize independent epitopes of the toxins. In the present work, the neutralization capacity of these two scFvs against two medically important toxins of the venom of Centruroides sculpturatus Ewing was evaluated. The results showed that these toxins are recognized by both scFvs with affinities between 1.8 × 10−9 and 6.1 × 10−11 M. For this reason, their ability to neutralize the venom was evaluated in mice, where scFv 10FG2 showed a better protective capacity. A combination of both scFvs at a molar ratio of 1:5:5 (toxins: scFv 10FG2: scFv LR) neutralized the venom without the appearance of any signs of intoxication. These results indicate a complementary activity of these two scFvs during venom neutralization.
Aflatoxin B1 Toxicity in Zebrafish Larva (Danio rerio): Protective Role of Hericium erinaceus
Authors: Di Paola Davide , Iaria Carmelo , Capparucci Fabiano , Cordaro Marika , Crupi Rosalia , Siracusa Rosalba , D’Amico Ramona , Fusco Roberta , Impellizzeri Daniela , Cuzzocrea Salvatore , Spanò Nunziacarla , Gugliandolo Enrico , Peritore Alessio Filippo
Published: October 2021

Aflatoxin B1 (AFB1), a secondary metabolite produced by fungi of the genus Aspergillus, has been found among various foods as well as in fish feed. However, the effects of AFB1 on fish development and its associated toxic mechanism are still unclear. In the present study, we confirmed the morphological alterations in zebrafish embryos and larvae after exposure to different AFB1 doses as well as the oxidative stress pathway that is involved. Furthermore, we evaluated the potentially protective effect of Hericium erinaceus extract, one of the most characterized fungal extracts, with a focus on the nervous system. Treating the embryos 6 h post fertilization (hpf) with AFB1 at 50 and 100 ng/mL significantly increased oxidative stress and induced malformations in six-day post-fertilization (dpf) zebrafish larvae. The evaluation of lethal and developmental endpoints such as hatching, edema, malformations, abnormal heart rate, and survival rate were evaluated after 96 h of exposure. Hericium inhibited the morphological alterations of the larvae as well as the increase in oxidative stress and lipid peroxidation. In conclusion: our study suggests that a natural extract such as Hericium may play a partial role in promoting antioxidant defense systems and may contrast lipid peroxidation in fish development by counteracting the AFB1 toxicity mechanism.
Undercover Agents of Infection: The Stealth Strategies of T4SS-Equipped Bacterial Pathogens
Authors: Bienvenu Arthur , Martinez Eric , Bonazzi Matteo
Published: October 2021

Intracellular bacterial pathogens establish their replicative niches within membrane-encompassed compartments, called vacuoles. A subset of these bacteria uses a nanochannel called the type 4 secretion system (T4SS) to inject effector proteins that subvert the host cell machinery and drive the biogenesis of these compartments. These bacteria have also developed sophisticated ways of altering the innate immune sensing and response of their host cells, which allow them to cause long-lasting infections and chronic diseases. This review covers the mechanisms employed by intravacuolar pathogens to escape innate immune sensing and how Type 4-secreted bacterial effectors manipulate host cell mechanisms to allow the persistence of bacteria.
Effects of Deoxynivalenol and Fumonisins Fed in Combination to Beef Cattle: Immunotoxicity and Gene Expression
Authors: Roberts Heaven L. , Bionaz Massimo , Jiang Duo , Doupovec Barbara , Faas Johannes , Estill Charles T. , Schatzmayr Dian , Duringer Jennifer M.
Published: October 2021

We evaluated the effects of a treatment diet contaminated with 1.7 mg deoxynivalenol and 3.5 mg fumonisins (B1, B2 and B3) per kg ration on immune status and peripheral blood gene expression profiles in finishing-stage Angus steers. The mycotoxin treatment diet was fed for a period of 21 days followed by a two-week washout period during which time all animals consumed the control diet. Whole-blood leukocyte differentials were performed weekly throughout the experimental and washout period. Comparative profiles of CD4+ and CD8+ T cells, along with bactericidal capacity of circulating neutrophils and monocytes were evaluated at 0, 7, 14, 21 and 35 days. Peripheral blood gene expression was measured at 0, 7, 21 and 35 days via RNA sequencing. Significant increases in the percentage of CD4−CD8+ T cells were observed in treatment-fed steers after two weeks of treatment and were associated with decreased CD4:CD8 T-cell ratios at this same timepoint (p ≤ 0.10). No significant differences were observed as an effect of treatment in terms of bactericidal capacity at any timepoint. Dietary treatments induced major changes in transcripts associated with endocrine, metabolic and infectious diseases; protein digestion and absorption; and environmental information processing (inhibition of signaling and processing), as evaluated by dynamic impact analysis. DAVID analysis also suggested treatment effects on oxygen transport, extra-cellular signaling, cell membrane structure and immune system function. These results indicate that finishing-stage beef cattle are susceptible to the immunotoxic and transcript-inhibitory effects of deoxynivalenol and fumonisins at levels which may be realistically encountered in feedlot situations.
Investigation of the Occurrence of Cyanotoxins in Lake Karaoun (Lebanon) by Mass Spectrometry, Bioassays and Molecular Methods
Authors: Hammoud Noura Alice , Zervou Sevasti-Kiriaki , Kaloudis Triantafyllos , Christophoridis Christophoros , Paraskevopoulou Aikaterina , Triantis Theodoros M. , Slim Kamal , Szpunar Joanna , Fadel Ali , Lobinski Ryszard , Hiskia Anastasia
Published: October 2021

Lake Karaoun is the largest artificial lake in Lebanon and serves multiple purposes. Recently, intensive cyanobacterial blooms have been reported in the lake, raising safety and aesthetic concerns related to the presence of cyanotoxins and cyanobacterial taste and odor (T&O) compounds, respectively. Here, we communicate for the first time results from a recent investigation by LC-MS/MS covering multiple cyanotoxins (microcystins (MCs), anatoxin-a, cylindrospermopsin, nodularin) in water and fish collected between 2019 and 2020. Eleven MCs were identified reaching concentrations of 211 and 199 μg/L for MC-LR and MC-YR, respectively. Cylindrospermopsin, anatoxin-a and nodularin were not detected. The determination of the total MCs was also carried out by ELISA and Protein Phosphatase Inhibition Assay yielding comparable results. Molecular detection of cyanobacteria (16S rRNA) and biosynthetic genes of toxins were carried out by qPCR. Untargeted screening analysis by GC-MS showed the presence of T&O compounds, such as β-cyclocitral, β-ionone, nonanal and dimethylsulfides that contribute to unpleasant odors in water. The determination of volatile organic compounds (VOCs) showed the presence of anthropogenic pollutants, mostly dichloromethane and toluene. The findings are important to develop future monitoring schemes in order to assess the risks from cyanobacterial blooms with regard to the lake’s ecosystem and its uses.
The Responsiveness of Bee Venom Phospholipase A2 on Regulatory T Cells Correlates with the CD11c+CD206+Population in Human Peripheral Blood Mononuclear Cells
Authors: Jo Heejin , Baek Hyunjung , Park Seon-Young , Goo Bonhyuk , Jung Woo-Sang , Bae Hyunsu , Nam Sang-Soo
Published: October 2021

Bee venom phospholipase A2 (bvPLA2) has been reported to have therapeutic effects such as neuroprotection, anti-inflammation, anti-nociception, anti-cancer properties, caused by increasing regulatory T cells (Tregs). The mechanism of Tregs modulation by bvPLA2 has been demonstrated by binding with the mannose receptor, CD206 in experimental models of several diseases. However, it remains unknown whether this mechanism can also be applied in human blood. In this study, we collected peripheral blood samples from healthy donors and analyzed the percentages of monocyte-derived dendritic cells with CD206 (CD206+ DCs) before expansion, the proportion of Tregs, and the subpopulations after expansion treated with bvPLA2 or PBS using flow cytometry and the correlations among them. The percentage of Tregs tended to be higher in the bvPLA2 group than in the control group. There were significant positive correlations between the CD206 population in hPBMC and the proportions of Tregs treated with bvPLA2, especially in the Treg fold change comparing the increase ratio of Tregs in bvPLA2 and in PBS. These findings indicate that bvPLA2 increased the proportion of Tregs in healthy human peripheral blood and the number of CD206+ DCs could be a predictor of the bvPLA2 response of different individuals.
Association between Obesity and COVID-19 Mortality in Peru: An Ecological Study
Authors: Ramírez-Soto Max Carlos , Alarcón-Arroyo Miluska , Chilcon-Vitor Yajaira , Chirinos-Pérez Yelibeth , Quispe-Vargas Gabriela , Solsol-Jacome Kelly , Quintana-Zavaleta Elizabeth
Published: October 2021

There is a gap in the epidemiological data on obesity and COVID-19 mortality in low and middle-income countries worst affected by the COVID-19 pandemic, including Peru. In this ecological study, we explored the association between body mass index (BMI), the prevalence of overweight and obesity, and the COVID-19 mortality rates in 25 Peruvian regions, adjusted for confounding factors (mean age in the region, mean income, gender balance and number of Intensive Care Unit (ICU) beds) using multiple linear regression. We retrieved secondary region-level data on the BMI average and prevalence rates of overweight and obesity in individuals aged ≥ 15 years old, from the Peruvian National Demographics and Health Survey (ENDES 2020). COVID-19 death statistics were obtained from the National System of Deaths (SINADEF) from the Peruvian Ministry of Health and were accurate as of 3 June 2021. COVID-19 mortality rates (per 100,000 habitants) were calculated among those aged ≥ 15 years old. During the study period, a total of 190,046 COVID-19 deaths were registered in individuals aged ≥ 15 years in 25 Peruvian regions. There was association between the BMI (r = 0.74; p = 0.00001) and obesity (r = 0.76; p = 0.00001), and the COVID-19 mortality rate. Adjusted for confounding factors, only the prevalence rate of obesity was associated with COVID-19 mortality rate (β = 0.585; p = 0.033). These findings suggest that as obesity prevalence increases, the COVID-19 mortality rates increase in the Peruvian population ≥ 15 years. These findings can help to elucidate the high COVID-19 mortality rates in Peru.
Chronic LCMV Infection Is Fortified with Versatile Tactics to Suppress Host T Cell Immunity and Establish Viral Persistence
Authors: Studstill Caleb J. , Hahm Bumsuk
Published: October 2021

Ever since the immune regulatory strains of lymphocytic choriomeningitis virus (LCMV), such as Clone 13, were isolated, LCMV infection of mice has served as a valuable model for the mechanistic study of viral immune suppression and virus persistence. The exhaustion of virus-specific T cells was demonstrated during LCMV infection, and the underlying mechanisms have been extensively investigated using LCMV infection in mouse models. In particular, the mechanism for gradual CD8+ T cell exhaustion at molecular and transcriptional levels has been investigated. These studies revealed crucial roles for inhibitory receptors, surface markers, regulatory cytokines, and transcription factors, including PD-1, PSGL-1, CXCR5, and TOX in the regulation of T cells. However, the action mode for CD4+ T cell suppression is largely unknown. Recently, sphingosine kinase 2 was proven to specifically repress CD4+ T cell proliferation and lead to LCMV persistence. As CD4+ T cell regulation was also known to be important for viral persistence, research to uncover the mechanism for CD4+ T cell repression could help us better understand how viruses launch and prolong their persistence. This review summarizes discoveries derived from the study of LCMV in regard to the mechanisms for T cell suppression and approaches for the termination of viral persistence with special emphasis on CD8+ T cells.
Application of Advanced Imaging to the Study of Virus–Host Interactions
Authors: Risco Cristina
Published: October 2021

Recent advances in light and electron microscopy are uncovering viral lifecycle events with a level of detail never before seen [...]
Norovirus Epidemiology and Genetic Diversity in Leipzig, Germany during 2013–2017
Authors: Ennuschat Nora , Härtel Sabine , Pietsch Corinna , Liebert Uwe G.
Published: October 2021

Globally and in all age groups, noroviruses are a main cause of gastroenteritis. To assess their local epidemiology and genetic diversity, stool samples of 7509 inpatients with gastrointestinal complaints from all age groups were analyzed. After detection of norovirus genogroup I and II RNA by real-time RT-PCR, viral capsids were genotyped by partial nucleic acid sequencing. In the case of GII.2 strains, polymerase genotypes were also assessed. Between October 2013 and September 2017, presence of norovirus RNA was shown in 611 samples (8.1%), of which 610 (99.8%) were typed successfully. Norovirus positivity rate was higher in patients aged below five years (14.8%) than in older patients (5.7%). Among the 611 norovirus positive samples, GII.4 (56.6%) strains prevailed, followed by GII.6 (11.3%), GII.3 (11.0%) and GII.2 (9.5%). The most common genogroup I (GGI) genotype was GI.3 (3.6%). In addition, rare genotypes such as GII.13, GII.14 and GII.26 were detected. Interestingly, GII.3 infections were most common in children under the age of five years. Assessment of polymerase genotypes in GII.2 viruses showed a shift from P2 to P16, with higher diversity in P2 sequences. The varying distribution of norovirus genotypes depending on season, age and setting of infection highlights the importance of frequent genotyping as a basis for vaccine development and needful adjustments.
Regulation of Avian Leukosis Virus Subgroup J Replication by Wnt/β-Catenin Signaling Pathway
Authors: Qiao Dandan , He Qian , Cheng Xiaowei , Yao Yongxiu , Nair Venugopal , Shao Hongxia , Qin Aijian , Qian Kun
Published: October 2021

Wnt/β-catenin signaling is a highly conserved pathway related to a variety of biological processes in different cells. The regulation of replication of various viruses by Wnt/β-catenin signaling pathway has been reported. However, the interaction between the Wnt/β-catenin pathway and avian leukosis virus is unknown. In the present study, we investigated the effect of modulating the Wnt/β-catenin pathway during avian leukosis virus subgroup J (ALV-J) infection. The activation of the Wnt/β-catenin pathway by GSK-3 inhibitor increased ALV-J mRNA, viral protein expression, and virus production in CEF cells. This increase was suppressed by iCRT14, one of the specific inhibitors of the Wnt/β-catenin signaling pathway. Moreover, treatment with iCRT14 reduced virus titer and viral gene expression significantly in CEF and LMH cells in a dose-dependent manner. Inhibition Wnt/β-catenin signaling pathway by knockdown of β-catenin reduced virus proliferation in CEF cells also. Collectively, these results suggested that the status of Wnt/β-catenin signaling pathway modulated ALV-J replication. These studies extend our understanding of the role of Wnt/β-catenin signaling pathway in ALV-J replication and make a new contribution to understanding the virus–host interactions of avian leukosis virus.
Newlavirus, a Novel, Highly Prevalent, and Highly Diverse Protoparvovirus of Foxes (Vulpes spp.)
Authors: Canuti Marta , Bouchard Émilie , Rodrigues Bruce , Whitney Hugh , Hopson Marti , Gilroy Cornelia , Stenson Garry , Dufour Suzanne , Lang Andrew , Verhoeven Joost
Published: October 2021

The genus Protoparvovirus (family Parvoviridae) includes several viruses of carnivores. We describe a novel fox protoparvovirus, which we named Newlavirus as it was discovered in samples from Newfoundland and Labrador, Canada. Analysis of the full non-structural protein (NS1) sequence indicates that this virus is a previously uncharacterized species. Newlavirus showed high prevalence in foxes from both the mainland (Labrador, 54/137, 39.4%) and the island of Newfoundland (22/50, 44%) but was not detected in samples from other carnivores, including coyotes (n = 92), lynx (n = 58), martens (n = 146), mink (n = 47), ermines (n = 17), dogs (n = 48), and ringed (n = 4), harp (n = 6), bearded (n = 6), and harbor (n = 2) seals. Newlavirus was found at similar rates in stool and spleen (24/80, 30% vs. 59/152, 38.8%, p = 0.2) but at lower rates in lymph nodes (2/37, 5.4%, p < 0.01). Sequencing a fragment of approximately 750 nt of the capsid protein gene from 53 samples showed a high frequency of co-infection by more than one strain (33.9%), high genetic diversity with 13 genotypes with low sequence identities (70.5–87.8%), and no geographic segregation of strains. Given the high prevalence, high diversity, and the lack of identification in other species, foxes are likely the natural reservoir of Newlavirus, and further studies should investigate its distribution.
Genetic Characterizations and Molecular Evolution of the Measles Virus Genotype B3’s Hemagglutinin (H) Gene in the Elimination Era
Authors: Zhou Nan , Li Mingma , Huang Yue , Zhou Lu , Wang Bei
Published: October 2021

Measles virus (MeV) genotype B3 is one globally significant circulating genotype. Here, we present a systematic description of long-term evolutionary characterizations of the MeV genotype B3’s hemagglutinin (H) gene in the elimination era. Our results show that the B3 H gene can be divided into two main sub-genotypes, and the highest intra-genotypic diversity was observed in 2004. MeV genotype B3’s H gene diverged in 1976; its overall nucleotide substitution rate is estimated to be 5.697 × 10−4 substitutions/site/year, and is slowing down. The amino acid substitution rate of genotype B3’s H gene is also decreasing, and the mean effective population size has been in a downward trend since 2000. Selection pressure analysis only recognized a few sites under positive selection, and the number of positive selection sites is getting smaller. All of these observations may reveal that genotype B3’s H gene is not under strong selection pressure, and is becoming increasingly conservative. MeV H-gene or whole-genome sequencing should be routine, so as to better elucidate the molecular epidemiology of MeV in the future.