m6A methyltransferase AflIme4 orchestrates mycelial growth, development and aflatoxin B1 biosynthesis in Aspergillus flavus.

Aflatoxin B1 (AFB1), a highly toxic secondary metabolite produced by Aspergillus flavus, poses a severe threat to agricultural production, food safety and human health. The methylation of mRNA m6A has been identified as a regulator of both the growth and AFB1 production of A. flavus. However, its intracellular occurrence and function needs to be elucidated. Here, we identified and characterized a m6A methyltransferase, AflIme4, in A. flavus. The enzyme was localized in the cytoplasm, and knockout of AflIme4 significantly reduced the methylation modification level of mRNA. Compared with the control strains, ΔAflIme4 exhibited diminished growth, conidial formation, mycelial hydrophobicity, sclerotium yield, pathogenicity and increased sensitivity to CR, SDS, NaCl and H2O2. Notably, AFB1 production was markedly inhibited in the A. flavus ΔAflIme4 strain. RNA-Seq coupled with RT-qPCR validation showed that the transcriptional levels of genes involved in the AFB1 biosynthesis pathway including aflA, aflG, aflH, aflK, aflL, aflO, aflS, aflV and aflY were significantly upregulated. Methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) analysis demonstrated a significant increase in m6A methylation modification levels of these pathway-specific genes, concomitant with a decrease in mRNA stability. These results suggest that AflIme4 attenuates the mRNA stability of genes in AFB1 biosynthesis by enhancing their mRNA m6A methylation modification, leading to impaired AFB1 biosynthesis. Our study identifies a novel m6A methyltransferase AflIme4 and highlights it as a potential target to control A. flavus growth, development and aflatoxin pollution.

Spatial and temporal distribution characteristics and influencing factors of tourism eco-efficiency in the Yellow River Basin based on the geographical and temporal weighted regression model.

With economic progression in China, Yellow River Basin serves as a critical economic belt, which has also been recognized as a cradle of Chinese culture. A watershed is a complex structure of social, economic, and natural factors, and the diversity of its components determines its complexity. Studies on the spatiotemporal distribution characteristics and factors influencing the tourism eco-efficiency at the watershed scale are crucial for the sustainable regional socio-economic development, maintaining a virtuous cycle of various ecosystems, and comprehensively considering the utilization and coordinated development of various elements. Based on tourism eco-efficiency, the coordination degree of regional human-land system and the sustainable development levels can be accurately measured. With the tourism eco-efficiency in the Yellow River Basin from 2009 to 2019, the present study considers 63 cities in the Yellow River Basin as the research area by adopting the super-efficiency slacks-based measure (Super-SBM) model. Methods such as trend surface analysis, spatial autocorrelation analysis, elliptic standard deviation analysis, and hot spot analysis were used to explore their spatiotemporal distribution and evolution characteristics. The geographical and temporal weighted regression (GTWR) model was used to determine the factors influencing the tourism eco-efficiency value. The findings are as follows: ①The level of tourism eco-efficiency in the Yellow River Basin is not high, exhibiting a fluctuating upward trend. ②The tourism eco-efficiency in the Yellow River Basin shows significant spatial interdependence and agglomeration. Furthermore, the track of the center of gravity moves from northeast to southwest. ③ The tourism eco-efficiency in the Yellow River Basin is affected by various factors, with the economic development level having the greatest influence.

Estragole Inhibits Growth and Aflatoxin Biosynthesis of Aspergillus flavus by Affecting Reactive Oxygen Species Homeostasis.

A variety of essential oils and edible compounds have been widely recognized for their antifungal activity in recent years. In this study, we explored the antifungal activity of estragole from Pimenta racemosa against Aspergillus flavus and investigated the underlying mechanism of action. The results showed that estragole had significant antifungal activity against A. flavus, with a minimum inhibitory concentration of 0.5 µL/mL against spore germination. Additionally, estragole inhibited the biosynthesis of aflatoxin in a dose-dependent manner, and aflatoxin biosynthesis was significantly inhibited at 0.125 µL/mL. Pathogenicity assays showed that estragole had potential antifungal activity against A. flavus in peanut and corn grains by inhibiting conidia and aflatoxin production. Transcriptomic analysis showed that the differentially expressed genes (DEGs) were mainly related to oxidative stress, energy metabolism, and secondary metabolite synthesis following estragole treatment. Importantly, we experimentally verified reactive oxidative species accumulation following downregulation of antioxidant enzymes, including catalase, superoxide dismutase, and peroxidase. These results suggest that estragole inhibits the growth and aflatoxin biosynthesis of A. flavus by modulating intracellular redox homeostasis. These findings expand our knowledge on the antifungal activity and molecular mechanisms of estragole, and provide a basis for estragole as a potential agent against A. flavus contamination. IMPORTANCE Aspergillus flavus contaminates crops and produces aflatoxins, carcinogenic secondary metabolites which pose a serious threat to agricultural production and animal and human health. Currently, control of A. flavus growth and mycotoxin contamination mainly relies on antimicrobial chemicals, agents with side effects such as toxic residues and the emergence of resistance. With their safety, environmental friendliness, and high efficiency, essential oils and edible compounds have become promising antifungal agents to control growth and mycotoxin biosynthesis in hazardous filamentous fungi. In this study, we explored the antifungal activity of estragole from Pimenta racemosa against A. flavus and investigated its underlying mechanism. The results demonstrated that estragole inhibits the growth and aflatoxin biosynthesis of A. flavus by modulating intracellular redox homeostasis.

Putative C2H2 Transcription Factor AflZKS3 Regulates Aflatoxin and Pathogenicity in Aspergillus flavus.

Aflatoxin is a carcinogenic secondary metabolite that poses a serious threat to human and animal health. Some C2H2 transcription factors are associated with fungal growth and secondary metabolic regulation. In this study, we characterized the role of AflZKS3, a putative C2H2 transcription factor based on genome annotation, in the growth and aflatoxin biosynthesis of A. flavus and explored its possible mechanisms of action. Surprisingly, the protein was found to be located in the cytoplasm, and gene deletion in A. flavus resulted in defective growth and conidia formation, as well as increased sensitivity to the fluorescent brightener Calcofluor white, Congo red, NaCl, and sorbitol stress. Notably, the biosynthesis of aflatoxin B1 was completely inhibited in the ΔAflZKS3 deletion strain, and its ability to infect peanut and corn seeds was also reduced. RNA sequencing showed that differentially expressed genes in the ΔAflZKS3 strain compared with the control and complementation strains were mainly associated with growth, aflatoxin biosynthesis, and oxidative stress. Thus, AflZKS3 likely contributes to growth, cell development, and aflatoxin synthesis in A. flavus. These findings lay the foundation for a deeper understanding of the roles of C2H2 transcription factors in A. flavus and provide a potential biocontrol target for preventing aflatoxin contamination.

Quantitative Acetylome Analysis of Soft Wheat Seeds during Artificial Ageing.

Lysine acetylation (Kac) is a protein post-translational modification (PTM) widely found in plants that plays vital roles in metabolic pathways. Although seed germination and development are regulated by Kac, its potential function in seed ageing remains to be investigated. Our preliminary study demonstrated that Kac levels were altered during wheat seed artificial ageing. However, its specific role in this process still needs to be elucidated. Here, we performed quantitative acetylation proteomics analysis of soft wheat seeds with different germination rates during artificial ageing. A total of 175 acetylation proteins and 255 acetylation modification sites were remarkably changed. The differentially acetylated proteins were enriched in metabolism; response to harsh intracellular environment, such as ROS; protein storage and processing. Notably, expression, point mutation to mimic Kac by K to Q mutation at K80 and K138, protein purification and enzyme activity detection revealed that the Kac of ROS-scavenging glutathione transferase attenuated its activity, indicating that the defense ability of wheat seeds to stress gradually diminished, and the ageing process was inevitable. Collectively, our data provide a basis for further understanding the roles of Kac in seed ageing and might aid in the development of new techniques to prolong seed viability and food quality.

Relationship quality and exhibitors' sustainable willingness to participate in exhibitions: A sociocultural perspective.

Exhibition is a new economic business form in China. From a stakeholder perspective, all important roles in the context of hospitality and tourism are talents. From a socio-cultural perspective, interpersonal relationship quality plays a vital role in business and industrial operations. This constructs a causal model of relationship quality between exhibitors and exhibition organizers, and examined its influence on exhibitors' willingness to sustainably participate in exhibitions. Data collected from a total of 251 exhibitors from 4 nation-representative exhibitions in Beijing were analyzed. The results found that the four antecedent variables-guanxi (as distinctive from relationship quality), service quality, communication, and exhibition effectiveness-have significant impacts on the relationship quality between exhibitors and exhibition organizers, which in turn, affect exhibitors' willingness to participate in subsequent exhibitions (i.e., exhibitor loyalty). These findings provide a theoretical basis and policy recommendations talent management in exhibition context.

More than just statics: altered complexity of dynamic amplitude of low-frequency fluctuations in the resting brain after stroke.

Objective.Previous neuroimaging studies mainly focused on static characteristics of brain activity, and little is known about its characteristics over time, especially in post-stroke (PS) patients. In this study, we aimed to investigate the static and dynamic characteristics of brain activity after stroke using functional magnetic resonance imaging (fMRI).Approach.Twenty ischemic PS patients and nineteen healthy controls (HCs) were recruited to receive a resting-state fMRI scanning. The static amplitude of low-frequency fluctuations (sALFFs) and fuzzy entropy of dynamic ALFF (FE-dALFF) were applied to identify the stroke-induced alterations.Main results.Compared with the HCs, PS patients showed significantly increased FE-dALFF values in the right angular gyrus (ANG), bilateral precuneus (PCUN), and right inferior parietal lobule (IPL) as well as significantly decreased FE-dALFF values in the right postcentral gyrus (PoCG), right dorsolateral superior frontal gyrus (SFGdor), and right precentral gyrus (PreCG). The receiver operating characteristic analyses demonstrated that FE-dALFF and sALFF possess comparable sensitivity in distinguishing PS patients from the HCs. Moreover, a significantly positive correlation was observed between the FE-dALFF values and the Fugl-Meyer Assessment (FMA) scores in the right SFGdor (r= 0.547), right IPL (r= 0.522), and right PCUN (r= 0.486).Significance.This study provided insight into the stroke-induced alterations in static and dynamic characteristics of local brain activity, highlighting the potential of FE-dALFF in understanding neurophysiological mechanisms and evaluating pathological changes.

Histone 2-Hydroxyisobutyryltransferase Encoded by Afngg1 Is Involved in Pathogenicity and Aflatoxin Biosynthesis in Aspergillus flavus.

Aflatoxin, a carcinogenic secondary metabolite produced by Aspergillus flavus, is a significant threat to human health and agricultural production. Histone 2-hydroxyisobutyrylation is a novel post-translational modification that regulates various biological processes, including secondary metabolism. In this study, we identified the novel histone 2-hydroxyisobutyryltransferase Afngg1 in A. flavus, and explored its role in cell growth, development and aflatoxin biosynthesis. Afngg1 gene deletion markedly decreased lysine 2-hydroxyisobutyrylation modification of histones H4K5 and H4K8 compared with the control strain. Additionally, Afngg1 deletion inhibited mycelial growth of A. flavus, and the number of conidia and hydrophobicity were significantly decreased. Notably, aflatoxin B1 biosynthesis and sclerotia production were completely inhibited in the ΔAfngg1 strain. Furthermore, the pathogenicity of the ΔAfngg1 strain infecting peanut and corn grains was also diminished, including reduced spore production and aflatoxin biosynthesis compared with A. flavus control and Afngg1 complementation strains. Transcriptome analysis showed that, compared with control strains, differentially expressed genes in ΔAfngg1 were mainly involved in chromatin remodelling, cell development, secondary metabolism and oxidative stress. These results suggest that Afngg1 is involved in histone 2-hydroxyisobutyrylation and chromatin modification, and thus affects cell development and aflatoxin biosynthesis in A. flavus. Our results lay a foundation for in-depth research on the 2-hydroxyisobutyrylation modification in A. flavus, and may provide a novel target for aflatoxin contamination prevention.

Reduced Complexity in Stroke with Motor Deficits: A Resting-State fMRI Study.

Recently, alterations of complexity due to brain disorders have been demonstrated using brain entropy (BEN), while the changes of brain complexity in stroke, a common cerebrovascular disease, remain unclear. In this research, resting-state functional magnetic resonance imaging (fMRI) was performed to explore the alterations of brain complexity using BEN in twenty stroke patients with motor deficits and nineteen matched healthy controls. The sample entropy (SampEn) was applied to build the BEN mapping for each participant. Compared with healthy controls, stroke patients exhibited lower BEN values in the contralesional precentral gyrus (preCG), bilateral dorsolateral frontal gyrus (SFGdor) and bilateral supplementary motor area (SMA). Moreover, significantly positive correlations between BEN values and Fugl-Meyer Assessment scores were detected in the ipsilesional SFGdor and ipsilesional SMA. Mutual information independence was observed between BEN and regional homogeneity (ReHo), amplitude of low-frequency fluctuations (ALFF), respectively, in the stroke patients. Our findings implied that brain complexity had been impacted after stroke, and also suggested that BEN could be a complementary tool for evaluating the motor impairment after stroke.

[Selectivity rank regionalization of Paeonia lactiflora based on fuzzy method].

For optimal adaptive cultivation region selection, we used ecology factors characterized Duolun region as model area to carry out the adaptive habitat division of Paeonia lactiflora. Similar priority comparison of ecology factors.in 91 cities were calculated by Fuzzy methods, then, distance of the ecology factors were transferred to spacial model by geography information system (,GIS) and modified by soil utilization map of China. The results showed that P. lactiflora were mainly distributed in the Daxing'an Mountain, Changbaishan and qinling range which were divided into six grades of suitable regions belonging to three geographical distributed units. The most similar areas to Duolun were Huade, Xilinhaote, Suolun and Zhangbei. P. lactiflora's distribution and quality are relevant with longitude and latitude, and temperature and rainfall.

[Study on climate regionalization of Artemisia annuua in Guangxi].

OBJECTIVE: To analyze the major effective factors under the climatic conditions of Guangxi which influence artemisinin content, in order to determine the best planting region. METHOD: The correlation, the gradually regression analysis with the statistical analysis system, the geography space analysis and the regionalization with GIS were used for the study. RESULT AND CONCLUSION: The temperature and the sunshine-hour were the major effective factors to artemisinin content, followed by the rainfall amount, the humidity showed less influence, and wind speed had no effect; And the climatic factors of seedling stage and the flowering season were the most influences to the artemisinin content. The artemisinin content was higher during the flowering season, in the region of temperature relatively lower and the rainfall amount smaller. The knoll and the mountainous region in northeast and southwest of Guangxi is the best suitable region for the Artemisia annua planting. The plain area in the southeast and middle of Guangxi is the not suitable region; Other areas are suitable regions for the A. annua planting.