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This study constructs a multi-player evolutionary game of local governments, tourism enterprises, and residents to analyze the stability strategies of game players in ecotourism protective development. The results show that the evolutionary game system of ecotourism conservation development can form four kinds of stable strategies under different conditions. The marginal influence of restrictive factors on the players’ strategic choice is more significant than that of incentive factors. Government penalties and incentives promote tourism enterprises to choose protective development strategies, and residents to choose supervision strategies. When higher protective development rewards exceed the government’s support capacity, the probability of local governments choosing active supervision strategies will decrease. Tourism enterprises will also reduce the probability of choosing protective development strategies due to the lack of effective supervision. The research results can help decision-makers to formulate ecotourism protection and development policies, and promote the sustainable development of ecotourism.

The n-octanol/water partition coefficient (log P) is an important parameter to characterize the overall hydrophobicity of organic compounds. Reversed-phase liquid chromatography (RPLC) has been recommended as an effective method for the indirect determination of log P by the Organization for Economic Cooperation and Development (OECD). Using RPLC, most studies focus on the determination of log P or the apparent n-octanol/water partition coefficient (log D) of neutral compounds and weakly ionized compounds. However, the experimental log P or log D values of strongly ionized compounds have rarely been reported. In our previous work, the experimental log D of strongly ionized compounds could be determined well by ion-pair reversed-phase liquid chromatography (IP-RPLC) on an octadecyl-poly(vinyl alcohol) column using the log D-log kw-IP model established by different types of model compounds. However, the universality of this strategy for different chromatographic columns has yet to be verified. In this study, the retention behavior of neutral compounds, phenolic acids, carboxylic acids, sulfonic acids, and some amphoteric compounds was systematically investigated on a silica-based C18 column (150 mm×4.6 mm, 5 μm) via ion-suppressed RPLC (IS-RPLC) and IP-RPLC, respectively. In the IS-RPLC mode, methanol and 20 mmol/L ammonium dihydrogen phosphate buffer (pH 7.0) were used as the mobile phase to perform isocratic elution at different methanol ratios. The log kw values of the test compounds were obtained using the linear solvent strength (LSS) model. Neutral compounds, weakly ionized phenolic acids and benzene carboxylic acids were then used as model compounds to establish the log D-log kw-IS model. The quantitative structure-retention relationship (QSRR) model, including structure-related descriptors like the charge (ne) and Abraham solvation parameters (A and B), exhibited much better correlation than the unary linear regression model between log D and log kw-IS. The log D7.0 (log D under pH 7.0) values of 19 ionized compounds were then determined by the model; the determined compounds were used as model compounds and validation compounds in IP-RPLC. In the IP-RPLC mode, besides methanol and ammonium dihydrogen phosphate buffer, the mobile phase also contained tetrabutylammonium bromide, as an ion-pair reagent. The retention behaviors of all tested compounds conformed well with the LSS model even under IP-RPLC, with a log k-φ linear correlation coefficient (R2) greater than 0.99. The log D-log kw-IP model was then established using 62 compounds as a mixed model set, including neutral, weakly ionized, and strongly ionized compounds. Similarly, by introducing ne, A, and B, the log D-log kw-IP model showed good linearity, with R2 greater than 0.94. Comparing the log D-log kw-IP model established on the silica-based C18 column in this work with that established on a poly(vinyl alcohol)-based C18 column in our previous work, ne, A, and B contributed more to the model in this work, indicating there was a greater secondary effect on the silica-based column. To confirm the reliability of the log D-log kw-IP model, three different types of acidic compounds were used as validation compounds. The predicted log D of the three ionic compounds was very similar to that determined by the shake-flask method (SFM)/slow stirring method (SSM) or IS-RPLC method in this work, confirming the reliability of the model. Based on the above results, the log D7.0 values of eight strongly ionized compounds were predicted by IP-RPLC. The findings suggested that IP-RPLC is a promising method to predict the experimental log D of strongly ionized compounds, and that the conventional silica-based C18 column offers more flexible options in log D determination.

Abnormal elongation of the polyglutamine tract transforms exon 1 of the Huntingtin protein (Htt-exon-1) from wildtype to pathogenic form, and causes Huntington's disease. As an intrinsically disordered protein, the structural ensemble of Htt-exon-1 is highly heterogeneous and the detailed conformation of toxic species is still under debate. Ispinesib, a potential small-molecule drug, has been identified to selectively link the pathogenic Htt-exon-1 into the autophagosome to degrade, thus opening an innovative therapeutic direction. However, the molecular mechanisms behind this selectivity remain largely elusive. Herein, we carry out extensive molecular dynamics simulations with an enhanced sampling method to investigate the ispinesib inducing conformational changes of pathogenic and wildtype Htt-exon-1 and the corresponding binding mechanisms. Our simulations reveal that the ispinesib binding induces opposite conformational changes in pathogenic and wildtype Htt-exon-1

Background Fragaria nilgerrensis is a diploid wild strawberry, which is densely covered with yellow-brown sericeous on the whole plant, giving them excellent drought resistance. Hitherto, the general mechanism of drought resistance of F. nilgerrensis is unknown. We therefore investigated the drought response regulatory networks of F. nilgerrensis based on the integrated analysis of DNA methylation, transcriptome and physiological traits during four continuous time points under drought stress. Results The most differentially expressed genes (DEGs) and the corresponding physiological changes were found at 8 days (T8) compared with 0 day (T0, control). Methylome analysis revealed slight dynamic changes in genome-wide mC levels under drought conditions, while the most hypomethylated and hypermethylated regions were identified at T4 and T8. Association analysis of methylome and transcriptome revealed that genes that were not expressed in mCHG and mCHH contexts exhibited the expected hypermethylation levels, and highly expressed genes exhibited corresponding hypomethylation levels in the gene body, but CG methylation showed the opposite trend. Notably, hypomethylation was found to contribute to the increase in gene expression levels during the drought-critical period (T8). Then, the identified 835 differentially methylated and expressed genes were grouped into four clustering patterns to characterize their functions. The genes with either negative or positive correlation between methylation and gene expression were mainly associated with Kinases, ROS synthesis, scavenging, ABA signal pathway, etc. Consistently, weighted gene co-expression network analysis (WGCNA) revealed Hub genes including NCED, CYP707A2, PP2Cs and others that play important roles in the ABA signaling pathway. Conclusions F. nilgerrensis drought is dominated by ABA-dependent pathways, possibly accompanied by ABA-independent crosstalk. DNA methylation affects gene expression, although there is no common pattern or correlation between DNA methylation and gene expression on gene number. Maintaining the balance between ROS regeneration and scavenging is an important factor in drought resistance in F. nilgerrensis. These results would deepen our understanding of drought resistance and its application in breeding in strawberry.

Liquid-liquid phase separation (LLPS) is involved in both physiological and pathological processes. The intrinsically disordered protein Tau and its K18 construct can undergo LLPS in a distinct temperature-dependent manner, and the LLPS of Tau protein can initiate Tau aggregation. However, the underlying mechanism driving Tau LLPS remains largely elusive. To understand the temperature-dependent LLPS behavior of Tau at the monomeric level, we explored the conformational ensemble of Tau at different temperatures by performing all-atom replica-exchange molecular dynamic simulation on K18 monomer with an accumulated simulation time of 26.4 μs. Our simulation demonstrates that the compactness, β-structure propensity, and intramolecular interaction of K18 monomer exhibit nonlinear temperature-dependent behavior. 295DNIKHV300/326GNIHHK331/337VEVKSE342 make significant contributions to the temperature dependence of the β propensity of K18 monomer, while the two fibril-nucleating cores display relatively high β propensity at all temperatures. At a specific temperature, K18 monomer adopts the most collapsed state with exposed sites for both persistent and transient interactions. Given that more collapsed polypeptide chains were reported to be more prone to phase separate, our results suggest that K18 monomer inherently possesses conformational characteristics favoring LLPS. Our simulation predicts the importance of 295DNIKHV300/326GNIHHK331/337VEVKSE342 to the temperature-dependent conformational properties of K18, which is corroborated by CD spectra, turbidity assays, and DIC microscopy. Taken together, we offer a computational and experimental approach to comprehend the structural basis for LLPS by amyloidal building blocks.

Our simulations reveal that two enantiomeric catechins display a better disruptive effect on Aβ42 protofibril than their stereoisomer epicatechin. Unexpectedly, we find that catechins adopt both collapsed and extended states, while epicatechin populates only an extended state. Their different protofibril-disruptive effects are mostly attributed to the steric effect caused by the conformational differences.

The abuse of enrofloxacin (ENR) in aquaculture and the lack of monitoring of other metabolites except ciprofloxacin (CIP) may lead to unknown harmful effects on human health. In this study, ENR metabolites were screened in real fish samples based on ultrahigh-performance liquid chromatography coupled with Q-Orbitrap mass spectrometry combined with Compound Discoverer software, and another metabolite deethylene-ENR besides CIP was detected and identified for the first time. Correspondingly, a method for the determination of ENR and CIP and the semi-quantitative analysis of deethylene-ENR in aquatic products was established. Method validation illustrated that excellent linearity and satisfactory recoveries of analytes were obtained. Limits of detection of ENR and CIP were both 0.1 μg kg

Chlorpromazine (CPZ) is abused in animal husbandry and can be extensively metabolized in humans and animals. However, the actual monitoring mainly focuses on the parent compound but lacks attention to its metabolites. A method was developed and validated firstly for identification and determination of CPZ and its four major metabolites in animal-derived foods using ultrahigh-performance liquid chromatography coupled with quadrupole-Orbitrap mass spectrometry in combination with QuEChERS preparation method. Satisfactory recoveries of analytes spiked in fish and pork samples ranged from 72 to 117 %, and limits of quantification were 2.0 and 1.0 μg kg

The n-octanol–water partition coefficient (logP) is an important physicochemical parameter which describes the behavior of organic compounds. In this work, the apparent n-octanol/water partition coefficients (logD) of basic compounds were determined using ion-suppression reversed-phase liquid chromatography (IS-RPLC) on a silica-based C18 column. The quantitative structure–retention relationship (QSRR) models between logD and logkw (logarithm of retention factor corresponding to 100% aqueous fraction of mobile phase) were established at pH 7.0–10.0. It was found that logD had a poor linear correlation with logkw at pH 7.0 and pH 8.0 when strongly ionized compounds were included in the model compounds. However, the linearity of the QSRR model was significantly improved, especially at pH 7.0, when molecular structure parameters such as electrostatic charge ne and hydrogen bonding parameters A and B were introduced. External validation experiments further confirmed that the multi-parameter models could accurately predict the logD value of basic compounds not only under strong alkaline conditions, but also under weak alkaline and even neutral conditions. The logD values of basic sample compounds were predicted based on the multi-parameter QSRR models. Compared with previous work, the findings of this study extended the pH range for the determination of the logD values of basic compounds, providing an optional mild pH for IS-RPLC experiments.

Cellular and humoral immunity are both important in host defense against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although defects in SARS-CoV-2-specific T cell immunity have been found in patients with severe lung pathology, it is still largely unclear whether virus-specific T cells are sufficient for host protection. Here, we found that in a previously characterized cohort of convalescent subjects, one individual, though lacking detectable anti-viral neutralizing IgG antibodies, showed virus-specific T cell responses, both in CD4+ and CD8+ T cells. SARS-CoV-2-specific T cells in this and other individuals are maintained for up to 10 months. This study thus further supports a critical role of T cells in host defense against SARS-CoV-2, offering new insights into the design and evaluation of COVID-19 vaccines.

Cultivated hawthorn (Crataegus pinnatifida var. major) is an important medicinal and edible plant with a long history of use for health protection in China. Herein, we provide a de novo chromosome-level genome sequence of the hawthorn cultivar 'Qiu Jinxing'. We assembled an 823.41 Mb genome encoding 40,571 genes and further anchored the 779.24 Mb sequence into 17 pseudo-chromosomes, which account for 94.64% of the assembled genome. Phylogenomic analyses revealed that cultivated hawthorn diverged within the Maleae (apple tribe) from the combined clades of Malus and Pyrus at approximately 11.8 Mya. Notably, genes involved in the flavonoid and triterpenoid biosynthetic pathways have been significantly amplified in the hawthorn genome. In addition, our results indicated that the Maleae share a unique ancient tetraploidization event; however, no recent independent whole-genome duplication event was specifically detected in hawthorn. The amplification of long terminal repeat retrotransposons (e.g., Ty3/gypsy) contributed the most to the expansion of the hawthorn genome. Furthermore, we identified two paleo-sub-genomes in extant species of Maleae and found that these two sub-genomes showed different rearrangement mechanisms. We also reconstructed the ancestral chromosomes of Rosaceae and discussed two possible paleo-polyploid origin patterns (autopolyploidization or allopolyploidization) of Maleae. Overall, our study provides an improved context for understanding the evolution of Maleae species, and this new high-quality reference genome provides a useful resource for the horticultural improvement of hawthorn.

Additional file 3: Figure S1. Multiplesequence alignment of the SWEET17 from daylily (Hemerocallis fulva) andother plants.

Thyroid cancer (TC) is a frequently occurring malignant tumor with a rising steadily incidence. microRNA (miRNA/miR)-193a-3p is an miRNA that is associated with tumors, playing a crucial role in the genesis and progression of various cancers. However, the expression levels of miR-193a-3p and its molecular mechanisms in TC remain to be elucidated. The present study aimed to probe the expression of miR-193a-3p and its clinical significance in TC, including its underlying molecular mechanisms. Microarray and RNA sequencing data gathered from three major databases, specifically Gene Expression Omnibus (GEO), ArrayExpress and The Cancer Genome Atlas (TCGA) databases, and the relevant data from the literature were used to examine miR-193a-3p expression. Meta-analysis was also conducted to evaluate the association between clinicopathological parameters and miR-193a-3p in 510 TC and 59 normal samples from the TCGA database. miRWalk 3.0, and the TCGA and GEO databases were used to predict the candidate target genes of miR-193a-3p. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes and protein-protein interaction network enrichment analyses were conducted by using the predicted candidate target genes to investigate the underlying carcinogenic mechanisms. A dual luciferase assay was performed to validate the targeting regulatory association between the most important hub gene cyclin D1 (CCND1) and miR-193a-3p. miR-193a-3p expression was considerably downregulated in TC compared with in the non-cancer controls (P

Citrobacter rodentium colonizes at the colon and causes mucosal inflammation in mice. Previous studies have revealed the importance of the innate and adaptive immune response for controlling C. rodentium infection. In the present study, we examined the role of T follicular helper (Tfh) cells in intestinal C. rodentium infection using mice with Bcl6 deficiency in T cells. Tfh cells were absolutely required at the late, but not the early, phase to control infection. Compared with control mice, we observed systemic pathogen dissemination and more severe colitis in Tfh-deficient mice. Furthermore, the susceptibility of Tfh-deficient mice correlated with an impaired serum IgG1 response to infection, and serum Abs from infected wild-type mice protected Tfh-deficient mice from infection. The transfer of wild-type Tfh cells also restored the levels of IgG1 and led to effective clearance of the pathogens in Tfh-deficient mice. Moreover, during C. rodentium infection, IL-21– and IL-4–producing Tfh cells were increased obviously in wild-type mice, correlating with IgG1 as the major isotype in germinal center B cells. Taken together, our work highlights the requirement and the function of Tfh cells in regulating humoral response for the host protection against C. rodentium infection.

A new genus of Arundinarieae, Khoonmengia, is established to accommodate a unique new bamboo species, K. honbaensis, from central-southern Vietnam. The morphological features, habitats and distribution of Khoonmengia and related genera, i.e. Ampelocalamus and Hsuehochloa, are compared. The characters of its scrambling habit, internodes with brownish green dots, conspicuous nodes swollen at one side, elliptic buds wholly sunken into culm, extravaginal branching pattern, mid-culm branch complement with one central dominant branch elongating to reiterate the culm accompanied by several lateral slender branches, swollen culm sheath base with a distinctive zone of transverse wrinkles, synflorescence composed of only one spikelet, single or several to many synflorescences arranged into a raceme or panicle terminal on leafy branches, purple anthers and nut-like caryopsis with hardened pericarp and loosely adherent lemma and palea distinguish K. honbaensis from morphologically similar taxa. In order to investigate the phylogenetic position of this unknown bamboo, molecular phylogenetic analyses based on the nuclear gene GBSSI were also conducted, and the results proved that K. honbaensis is definitely a member of Arundinarieae with an isolated position, which also indicated that this species could not be assigned to any of the already described genera and supported the establishment of the new genus.

Tissue culture is an important tool for asexual propagation and genetic transformation of strawberry plants. In plant tissue culture, variation of DNA methylation is a potential source of phenotypic variation in regenerated plants. However, the genome wide dynamic methylation patterns of strawberry tissue culture remain unclear. In this study, we used whole-genome bisulfite sequencing (WGBS) to study genomic DNA methylation changes of a wild strawberry Fragaria nilgerrensis at six stages: from explants of shoot tips to outplanting and acclimation. Global methylation levels showed that CG sites exhibited the highest methylation level in all stages with an average of 49.5%, followed by CHG (33.2%) and CHH (12.4%). Although CHH accounted for the lowest proportion of total cytosine methylation, it showed the most obvious methylation change and the most of these changes occurred in the transposable element regions. The overall methylation levels alternately decreased and increased during the entire tissue culture process and the distribution of DNA methylation was non-uniform among different genetic regions. Furthermore, much more differentially methylated regions (DMRs) were detected in dedifferentiation and redifferentiation stages and most of them were transposable elements, suggesting these processes involved activating or silencing of amounts of transposons. The functional enrichment of the DMR-related genes indicated that genes involved in hormone metabolic processes, plant development and the stress response changed methylation throughout the tissue culture process. Finally, the quantitative real-time PCR (qRT-PCR) was conducted to examine the association of methylation and gene expression of a set of different methylated genes. Our findings give deeper insight into the epigenetic regulation of gene expression during the plant tissue cultures process, which will be useful in the efficient control of somaclonal variations and in crop improvement.

Significance Strawberry is a very popular fruit. The strawberry genus (Fragaria) has emerged as a model system for various fundamental and applied research in recent years. Here, by using high-throughput sequencing technologies, we provide de novo whole-genome sequences for five wild strawberry species and genome resequencing data for 128 additional accessions of key species. Our analyses resulted in robust estimates of the evolutionary history for most diploid strawberry species, the discovery of a new diploid species (Fragaria emeiensis Jia J. Lei), and the construction of a pan-genome for strawberry. We also examined the evolutionary dynamics of gene families. This study provides a powerful genomic platform and resource for future studies in strawberry., Strawberry (Fragaria spp.) has emerged as a model system for various fundamental and applied research in recent years. In total, the genomes of five different species have been sequenced over the past 10 y. Here, we report chromosome-scale reference genomes for five strawberry species, including three newly sequenced species’ genomes, and genome resequencing data for 128 additional accessions to estimate the genetic diversity, structure, and demographic history of key Fragaria species. Our analyses obtained fully resolved and strongly supported phylogenies and divergence times for most diploid strawberry species. These analyses also uncovered a new diploid species (Fragaria emeiensis Jia J. Lei). Finally, we constructed a pan-genome for Fragaria and examined the evolutionary dynamics of gene families. Notably, we identified multiple independent single base mutations of the MYB10 gene associated with white pigmented fruit shared by different strawberry species. These reference genomes and datasets, combined with our phylogenetic estimates, should serve as a powerful comparative genomic platform and resource for future studies in strawberry.

Abnormal aggregation of proteins into pathological amyloid fibrils is implicated in a wide range of devastating human neurodegenerative diseases. Intracellular fibrillary inclusions formed by Tau protein are characterized as the hallmark of tauopathies, including Alzheimer's disease and frontotemporal dementia. Heparin has been often used to trigger Tau aggregation in in vitro studies. However, the conformational changes induced by heparin and the underlying mechanism of promotion of Tau aggregation by heparin are not well understood. Structural characterization of Tau oligomers in the early stage of fibrillation is of great importance but remains challenging due to their dynamic and heterogeneous nature. R3, the third microtubule-binding repeat of Tau, contains the fibril-nucleating core (PHF6) and is crucial for Tau aggregation. In this study, utilizing extensive all-atom replica-exchange molecular dynamic simulations, we explored the conformational ensembles of R3 monomer/dimer in the absence and presence of heparin. Our results show that without heparin, both monomeric and dimeric R3 preferentially adopt collapsed β-sheet-containing conformations and PHF6 plays an important role in the formation of interchain β-sheet structures, while in the presence of heparin, R3 can populate relatively extended disordered states where chain dimension is similar to that of R3 in Tau filaments. Through electrostatic, hydrogen-bonding and hydrophobic interactions, heparin has a preference for interacting with residues V306/Q307/K317/K321/H329/H330/K331 which distribute throughout the entire sequence of R3, in turn acting as a template to extend R3 conformations. More importantly, heparin alters intramolecular/intermolecular interaction patterns of R3 and increases the intermolecular contact regions. Our results suggest that heparin remodels the conformations of R3 towards fibril-prone structures by increasing chain dimension and intermolecular contact regions, which may shed light on the atomic mechanism of heparin-induced amyloid fibrillization of Tau protein.

Ion-pair reversed-phase liquid chromatography (IP-RPLC) enhances separation by adding ion-pair reagents to the mobile phase, thereby improving the retention of oppositely charged solutes. IP-RPLC is primarily used for the separation and analysis of strongly ionized compounds. In IP-RPLC, researchers often focus more on the influence of the counter-ion type and concentration, buffer salt concentration and pH, and column temperature, on the retention behavior of solutes. However, the effects of the buffer salt type and non-counter ions in ion-pair reagents on the retention behavior of solutes have rarely been investigated. Accordingly, in this work, the effects of buffer salt types and non-counter ions on the retention behavior of strongly ionized compounds were investigated by IP-RPLC using 14 sulfonic acid compounds as model compounds. Experiments were performed using a silica-based C18 column with methanol as the organic modifier. In the first type of experiment, tetrabutylammonium bromide was kept unchanged as the ion-pair reagent in the mobile phase, and ammonium dihydrogen phosphate, ammonium chloride, and ammonium acetate were used as buffer salts, respectively. The retention factor (k) was obtained at different methanol ratios, and linear solvent strength (LSS) models were established to determine the log kw (logarithm of retention factors of solutes when 100% aqueous phases were used as the mobile phase) and S (intercept of the LSS model) values of each solute. All solutes exhibited the highest log kw with the ammonium chloride buffer system; most compounds also exhibited the highest S values with this system, except for 1,5-naphthalenedisulfonic acid, 4-methylbenzenesulfonic acid, 5-amino-2-nanphthalenesulfonic acid, and 4-hydroxybenzenesulfonic acid. However, the chromatographic hydrophobic indices (CHIs, log kw/S) of the solutes with different buffer salts were approximately equal. In the second type of experiment, ammonium dihydrogen phosphate was kept unchanged as the buffer salt in the mobile phase, and tetrabutylammonium bromide, tetrabutylammonium dihydrogen phosphate, tetrabutylammonium hydrogen sulfate, tetrabutylammonium nitrate, and tetrabutylammonium acetate were used as ion-pair reagents, respectively. Almost all solutes exhibited the highest S with the tetrabutylammonium acetate system, indicating that weakly ionized anions (such as acetate ions) in ion-pair reagents will improve the S values of sulfonic acid compounds. Interestingly, the CHIs of the solutes were almost the same for solutes with different non-counter ions. These results suggest that both, the buffer salt types and non-counter ions, influence the log kw and S values of sulfonic acid compounds. Comparison of the retention behavior of solutes with different mobile phases suggested ion-pair mechanisms as well as dynamic ion-exchange mechanisms plays role in the IP-RPLC retention of sulfonic acid compounds. In addition, with all the experimental mobile phases, the apparent n-octanol/water partition coefficient (log D) presented a good linear correlation with log kw, S, and CHI, respectively, by the introduction of structure-related descriptors such as charge (ne), Abraham solvation parameters (A and B), and the polar surface area (PSA). Considering the differences in the log kw and S values obtained with different buffer salts and non-counter ions, the CHIs were relatively stable; therefore, the CHI is more suitable for establishing a quantitative structure-retention relationship (QSRR) model in IP-RPLC, compared to log kw and S.

Anonymous communication technology has been proposed to conceal the identity and communication relationship of both parties in communication, mitigating the threats of communication surveillance. However, the traditional anonymous communication scheme is designed on the traditional network architecture, network devices have limited control over the network, which leads to the inefficiency of anonymous communication. Software Defined Networks (SDN) is a novel network architecture that manages network through controller. It has the characteristics of high efficiency and flexibility. However, in recent years, researches about anonymous communication of SDN exist many challenges, such as limitation of scenarios and lack of anonymity. To address these challenges, this paper, inspired by pseudonym changing, proposes a pseudonym-based anonymous routing mechanism under multi-controller SDN architecture, in which pseudonym-changing is used for hiding the identity of the communicating parties. Besides, to avoid routing error caused by address conflicts, an effective hash checking method is proposed to avoid anonymous address conflicts. Based on that, we also present an anonymity enhanced scheme that employs phantom routing to hide the sender in the routing path and a multicast mechanism to prevent traffic analysis attacks. Anonymity analysis and experiment show that this scheme can provide strong anonymity protection for distributed SDN without much time cost, and has good practicability.

Background Understanding how organisms evolve and adapt to extreme habitats is of crucial importance in evolutionary ecology. Altitude gradients are an important determinant of the distribution pattern and range of organisms due to distinct climate conditions at different altitudes. High-altitude regions often provide extreme environments including low temperature and oxygen concentration, poor soil, and strong levels of ultraviolet radiation, leading to very few plant species being able to populate elevation ranges greater than 4000 m. Field pennycress (Thlaspi arvense) is a valuable oilseed crop and emerging model plant distributed across an elevation range of nearly 4500 m. Here, we generate an improved genome assembly to understand how this species adapts to such different environments. Results We sequenced and assembled de novo the chromosome-level pennycress genome of 527.3 Mb encoding 31,596 genes. Phylogenomic analyses based on 2495 single-copy genes revealed that pennycress is closely related to Eutrema salsugineum (estimated divergence 14.32–18.58 Mya), and both species form a sister clade to Schrenkiella parvula and genus Brassica. Field pennycress contains the highest percentage (70.19%) of transposable elements in all reported genomes of Brassicaceae, with the retrotransposon proliferation in the Middle Pleistocene being likely responsible for the expansion of genome size. Moreover, our analysis of 40 field pennycress samples in two high- and two low-elevation populations detected 1,256,971 high-quality single nucleotide polymorphisms. Using three complementary selection tests, we detected 130 candidate naturally selected genes in the Qinghai-Tibet Plateau (QTP) populations, some of which are involved in DNA repair and the ubiquitin system and potential candidates involved in high-altitude adaptation. Notably, we detected a single base mutation causing loss-of-function of the FLOWERING LOCUS C protein, responsible for the transition to early flowering in high-elevation populations. Conclusions Our results provide a genome-wide perspective of how plants adapt to distinct environmental conditions across extreme elevation differences and the potential for further follow-up research with extensive data from additional populations and species.

Wang, Hui-Feng, Wang, Zheng-Feng, Qin, Qiao-Mei, Cao, Hong-Lin, Guo, Xiao-Ming (2021): Tigridiopalma longmenensis (Melastomataceae), a new species from Guangdong, China. Phytotaxa 500 (3): 241-247, DOI: 10.11646/phytotaxa.500.3.8, URL: http://dx.doi.org/10.11646/phytotaxa.500.3.8

Tigridiopalma longmenensis H.F. Wang, H.L. Cao & H.G. Ye, sp. nov. (Fig. 4) Type: ��� CHINA. Guangdong Province: Huizhou City, Longmen County, 23��39��� N, 114��3��� E, 150 m, 12 September 2020, H. F. Wang, H. L. Cao & H. G. Ye 20200912001 (holotype, IBSC, barcode number 0858304; isotypes, IBSC, barcode numbers 0858305 & 0858306). Diagnosis: ��� Tigridiopalma longmenensis is similar to T. magnifica in the herbaceous habit, the 5-merous flowers, dimorphic and unequal stamens, short stamens with the decurrent connective of anthers forming a short spur, and funnelform shaped capsules. However, the former differs from the latter by the inflorescences being polychasia (vs. scorpioid cymes), hypanthia with carinas on angles (vs. winged on angles), and the longer (antesepalous) stamens with a conspicuously white or pink spur (vs. without spurs) at the connective bases of anthers (Table 2, Fig. 2). Perennial herbs. Rhizomes usually woody. Stems erect, short, sparsely pubescent, 1���1.5 mm long. Leaves basal, with soft hairs when young, yellow puberulent when old; petiole terete, 4.4���18.4 cm long, succulent, sparsely pubescent, sulcate when old; blades membranous, narrowly cordate to ovate, 20.8���51.8�� 13.6���44.9 cm, margin ciliate and irregular abruptly denticulate, adaxially glabrous, abaxially densely furfuraceous, purplish red, puberulous on veins, secondary veins 2���3 pairs, tertiary veins parallel. Inflorescences axillary, polychasium consisting of 2���5 scorpioid cymes; peduncle 9.4���32.7 cm long, sometimes furfuraceous at base, ribbed when dry; bracts 0.8���8.7�� 0.5���4.3 cm, persistent. Pedicel 0.9���1.9 mm long, with carinas on angles, 0.2���0.5 mm wide, sometimes furfuraceous. Hypanthium funnelform to cup-shaped, 5-sided, apex truncate, carina 0.2���0.5 mm wide on angle. Calyx lobes 5, triangular to semiorbicular, 0.3���0.5 mm long. Petals 5, 1.1���1.6�� 0.8���0.9 cm, adaxially dark red, abaxially with white lines, broadly obovate, almost rhomboid, apex truncate, oblique, and apiculate. Stamens 10, dimorphic and unequal; longer stamens 5, antesepalous, filaments 1.6���1.9 cm long, anthers 0.8���1.2 cm long, connective decurrent, forming a conspicuous spur abaxially, white or pink, ca. 1 mm long, and two ventral tubercles, yellow, ca. 1 mm long; smaller stamens 5, antepetalous, filaments 1.1���1.4 cm long, anthers 0.5���0.8 cm long, connective decurrent, forming a spur abaxially, ca. 1 mm long and two ventral tubercles, yellow, ca. 1 mm long. Ovary ovoid, 5-celled, apex with membranous crown; crown 5-lobed, with irregularly denticulate margin; style 0.9���1.2 cm long, magenta, terete, slightly curved. Capsule dehiscing into 5 valves from the apex, valves ca. 2���3 mm long, with irregularly denticulate margin. Hypanthium partially covering the capsule, funnel-shaped, 6.5���7.5�� 9.1���10.2 mm, 5-sided, angles carinated. Seed numerous, brown, cuneate, 0.6���0.8�� 0.3���0.5 mm. Etymology: ���The specific epithet is derived from the type locality, Longmen County of Guangdong Province, China. Geographical distribution and habitat: ��� Tigridiopalma longmenensis is only known from Longmen County, Huizhou City, Guangdong Province, China (Fig. 1). It often occurs on the rock crevices near streamside in forests at low elevations of 93���175 m. IUCN conservation assessment: ���One population with more than 2500 individuals has been found in Longmen. There is no any significant or plausible threat to the habitat and the plant up to now. It is therefore evaluated as Endangered (EN B1a) according to IUCN Red List Criteria (IUCN 2019). Phenology: ���Flowering from August to October; fruiting from October to November. Additional specimens examined (paratypes): ��� CHINA. Guangdong Province: Huizhou city, Longmen County, Youtian Forest Farm, 23��38��� N, 114��2��� E, elev. 115 m, 20 August 2020, H. F . Wang & H. F. Zhu 20200820001 (IBSC); ibid., 24 October 2020, H. F . Wang & Z. H. Wu 20201024007 (IBSC); ibid., 23��39��� N, 114��3��� E, elev. 151 m, 26 November 2020, H. F . Wang, H. Dong & W. G. Zhu 20201126001 (IBSC)., Published as part of Wang, Hui-Feng, Wang, Zheng-Feng, Qin, Qiao-Mei, Cao, Hong-Lin & Guo, Xiao-Ming, 2021, Tigridiopalma longmenensis (Melastomataceae), a new species from Guangdong, China, pp. 241-247 in Phytotaxa 500 (3) on pages 244-246, DOI: 10.11646/phytotaxa.500.3.8, http://zenodo.org/record/5424632, {"references":["IUCN Standards and Petitions Subcommittee (2019) Guidelines for using the IUCN Red list Categories and Criteria. Version 14. Prepared by the Standards and Petitions Subcommittee. Available from: http: // www. iucnredlist. org / documents / RedListGuidelines. pdf (accessed 28 August 2020)"]}

International audience; With the increasing impact of the global warming, occurrences of cyanobacterial blooms in aquatic ecosystems are becoming a main worldwide ecological concern. Due to their capacity to produce potential toxic metabolites, interactions between the cyanobacteria, their cyanotoxins and the surrounding freshwater organisms have been investigated during the last past years. Non-targeted metabolomic analyses have the powerful capacity to study simultaneously a high number of metabolites and thus to investigate in depth the molecular signatures between various organisms encountering different environmental scenario, and potentially facing cyanobacterial blooms. In this way, the liver metabolomes of two fish species (Perca fluviatilis and Lepomis gibbosus) colonizing various peri-urban lakes of theÎle-de-France region displaying high biomass of cyanobacteria, or not, were investigated. The fish metabolome hydrophilic fraction was analyzed by 1 H NMR analysis coupled with Batman peak treatment for the quantification and the annotation attempt of the metabolites. The results suggest that similar metabolome profiles occur in both fish species, for individuals collected from cyanobacterial blooming lakes compared to organism from non-cyanobacterial dominant environments. Overall, such environmental metabolomic pilot study provides new research perspectives in ecology and ecotoxicology fields, and may notably provide new information concerning the cyanobacteria/fish eco-toxicological interactions.

Among the diverse toxic components produced by cyanobacteria, microcystins (MCs) are one of the most toxic and notorious cyanotoxin groups. Besides their potent hepatotoxicity, MCs have been revealed to induce potential reproductive toxicity in various animal studies. However, little is still known regarding the distribution of MCs in the reproductive organ, which could directly affect reproductive cells. In order to respond to this question, an acute study was conducted in adult medaka fish (model animal) gavaged with 10 µg.g-1 body weight of pure MC-LR. The histological and immunohistochemical examinations reveal an intense distribution of MC-LR within hepatocytes along with a severe liver lesion in the toxin-treated female and male fish. Besides being accumulated in the hepatocytes, MC-LR was also found in the connective tissue of the ovary and the testis, as well as in oocytes and degenerative spermatocyte-like structures. Both liver and gonad play important roles in the reproductive process of oviparous vertebrates. This observation constitutes the first observation of the presence of MC-LR in the reproductive cell of a vertebrate model with in vivo study. Our results, which provide intracellular localization of MC-LR in the gonad, advance our understanding of the potential reproductive toxicity of MC-LR in fish.

The expression changes of CD2-associated protein (CD2AP) can lead to kidney diseases with proteinuria, including nephrotic syndrome (NS). A recent study reported that miRNAs may be important transcriptional regulators. In this study, we found increased expression of miR-939-5p and decreased expression of CD2AP in the peripheral blood of patients with NS. However, miR-939-5p did not show a regulatory effect on the 3'-untranslated region of CD2AP. The expression levels of specific protein 1 and adenovirus E2 promoter-binding factor 1, important transcription regulators in the promoter region of CD2AP, were also not affected by microRNA (miR)-939-5p. We confirmed that miR-939-5p is in the nucleus by fluorescent in situ hybridization and cytoplasmic separation polymerase chain reaction. The promoter plasmid and miR-939-5p were cotransfected into HEK-293 cells, and the luciferase reporter gene assay was used to analyze the promoter activity. We found that miR-939-5p binds to a specific sequence in the CD2AP promoter. miR-939-5p was confirmed to reduce the recruitment of RNA polymerase II to the CD2AP promoter region by chromatin immunoprecipitation. These findings improve our understanding of the mechanism of miR-939-5p in NS and provide potential molecular therapeutic targets for NS.

With the development of image processing technology and the improvement of unmanned aerial vehicle (UAV) manufacture, it has been becoming a hot research topic to inspect the transmission line's failure. Here, a method of locating the area of insulator strings in the aerial image captured by UAV system is been introduced. At first, the aerial image is converted to HSV colour space model, and the components of H and S are filtered to segment the insulator strings and background areas. Considering some background areas have the similar colour with the insulator string, the result of segmentation will contain some background areas. Then, the image of result is divided into small pieces with non-overlapping windows. The information of texture on each window is used to remove the remaining background area. The outline of the insulator strings in the image can be obtained. It is easily to detect the edge of the insulator string and locate the area of the insulator string using the outline image. At last, some insulator string images have been used to illustrate the processing of the method. Compared with the method using RGB colour space model, the results of method here is effective and reliable.

Dendrobium wangliangii is an endangered and epiphytic orchid with tolerance to seasonally extreme arid conditions and occurs exclusively in the hot-dry valley area of southwestern China. To reveal its molecular basis responsible for ecological adaptation, large-scale transcriptome sequencing was performed using Illumina sequencing with pooled mRNA extracted from whole plants and pseudobulbs during drought and rainy seasons. Based on the target transcript selection, the differentially expressed genes were related to 8 well-known drought-tolerant categories, and to morphological traits in resistance to water stress including pseudobulbs and roots. Further gene ontology enrichment analysis revealed that ‘nucleoside/nucleotide and ribonucleoside/ribonucleotide metabolic processes’ and ‘response to stimulus’ were the two most important aspects in resistance to drought stress with respect to the whole plant. In addition, the difference in the number and category of differentially expressed genes in whole plant and stem suggested the involvement of genes specifically localized in the stem, such as GTP-binding protein, lipases, signaling related transcripts and those involved in the ATP metabolic process. The comprehensive analysis of the epiphytic orchid in response to water deprivation indicates that integral tactics lead to active adaptation as a basal defense response to drought stress by the endangered epiphyte, including the collaboration of metabolic processes, responses to a various stimulus and other candidate genes contribute to its extreme drought tolerance. Insights from this study can be further utilized to understand stress-responsive genes in other medicinally important species and to improve the drought tolerance of food crops. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s12298-018-0607-3) contains supplementary material, which is available to authorized users.