Search

Portfolio problem is the research direction of securities, finance and other markets. In order to study the situation of relevant markets and asset allocation, this paper selects the representatives of the Internet, medicine, finance, new energy vehicles and tobacco industries as the research objects. Based on the mean variance model, this paper uses CAPM model and FF model to calculate the optimal portfolio. The results show that the new energy automobile industry of the Internet is better under the CAPM model, while the financial industry performs well under the FF model. At the same time, the pharmaceutical industry can effectively reduce the risk while ensuring the income. At the same time, this paper discusses the portfolio under the condition of adding etf to further reduce risk. Under the condition of pursuing high Sharpe ratio and low risk, it can greatly affect the optimal portfolio. The research results are helpful to relevant investors.

Myelocytomatosis (MYC) transcription factors are crucial mediators of the jasmonate signaling pathway, which mediates the growth and developmental processes of plants. However, the function of MYC genes in tomato, Solanum lycopersicum (SlMYC), remains poorly understood. In this study, we have identified 14 non-redundant SlMYC genes across the genome of tomatoes. Six of the twelve chromosomes included these genes, and four syntenic pairs of SlMYC were identified. According to the results of phylogenetic analysis, 14 SlMYC genes were clustered into classes I, II, III, and IV, and their functional domains were predicted. The SlMYC upstream promoter region contained a variety of light-, stress-, and hormone-response regulatory elements. The expression of the 14 SlMYC genes differed significantly across organs. SlMYCs primarily showed an upregulation trend after methyl jasmonate (MeJA) treatment. In contrast, after treatment with sodium chloride (NaCl), SlMYCs showed a trend of downregulation. However, there were differences in the expression patterns of SlMYCs after mannitol treatment. Using clustered regularly interspaced short palindromic repeats/Cas 9 (CRISPR/Cas 9) technology, the loss-of-function of SlMYC1 (slmyc1) was obtained. The slmyc1 tomato plants demonstrated reduced resistance to NaCl and mannitol stress compared to wild-type plants due to their shorter root length and higher reactive oxygen species (ROS) content. In brief, this study provides valuable information about the taxonomy of the SlMYC genes in tomato. It establishes a foundation for future research on the mechanism by which SlMYC influences plant development and stress response.

Phenolic glycosides are the important bioactive molecules, and their bioavailability can be influenced by enzyme hydrolysis, such as β-glucosidases (EC3.2.1.21) and other glycosyl hydrolases (GHs). Wood rotting fungi possess a superfamily of GHs, but little attention has been paid to the GHs and their potential applications in biotransformation of phenolic glycosides. In this study, two GH3 gene family members of Trametes trogii S0301, mainly expressed in the carbon sources conversion stage were cloned, and TtBgl3 coded by T_trogii_12914 showed β-glucosidase activity toward 4-nitrophenyl β-D-glucopyranoside (pNPG). The recombinant TtBgl3 preferred an intermediately neutral optimum pH with >80% of the maximum activity at pH 5.0–7.0 and was stable at a wide range of pH (5.0–10.0). Phenolic glycosides transformation experiments showed that TtBgl3 was a dual-activity enzyme with both activities of aryl-β-D-glucosidase and β-glucuronidase, and could hydrolyze the β-glucoside/glucuronide bond of phenolic glycosides. Under optimized conditions, the recombinant TtBgl3 had much higher transformation efficiency toward the β-glucoside bond of gastrodin, esculin and daidzin than β-glucuronide bond of baicalin, with the transformation rate of 100 and 50%, respectively. Our homology modeling, molecular docking, and mutational analysis demonstrated that His85 and Lys467 in the acceptor-binding pocket of TtBgl3 were the potential active sites. The point mutation of His85 and Lys467 leads to the significantly impaired catalytic activity toward pNPG and also the weak transformation efficiency toward gastrodin. These findings provide insights for the identification of novel GH3 β-glucosidases from T. trogii and other wood-rotting fungi. Furthermore, TtBgl3 might be applied as green and efficient biological catalysts in the deglycosylation of diverse phenolics to produce bioactive glycosides for drug discovery in the future.

Guanosine triphosphate (GTP) cyclohydrolase I (GCH1) is the limiting enzyme of the tetrahydrobiopterin (BH4) synthesis pathway. The disruption of gch1 gene may cause conditional lethality due to folic acid auxotrophy in microorganisms, although the function of gch1 in basidiomycetes has not been deciphered so far. In the present study, gch1 expression in Cyclocybe aegerita (cagch1) was downregulated using the RNAi method, which resulted in growth retardation in both solid and liquid medium, with the hyphal tips exhibiting increased branching compared to that in the wild strain. The development of fruiting bodies in the mutant strains was significantly blocked, and there were short and bottle-shaped stipes. The transcriptional profile revealed that the genes of the MAPK pathway may be involved in the regulation of these effects caused by cagch1 knockdown, which provided an opportunity to study the role of gch1 in the development process of basidiomycetes.

H2O2 is an important signaling molecule that involved in multiple physiological metabolic activities in plants. Excess H2O2 can destroy biological macromolecules to poison the cell. Thioredoxin peroxidase (Tpx) plays an important role in protecting plants from oxidative damage by clearing the H2O2. In this study, tomato Tpx (SlTpx) gene was cloned and bioinformatic analysis was done. The mRNA transcript level of SlTpx in tomato roots and leaves were increased significantly after NaCl stress treatment. SlTpx overexpression transgenic tobacco plants were obtained to study its function under NaCl stress. The seed germination rate of SlTpx overexpression plants was higher than that in wild plants (WT) under NaCl treatment. The ROS and NO accumulation in transgenic tobacco root tips were all less than in WT under NaCl stress. Meanwhile,compared with salt stress, transgenic plants had low ROS accumulation, high antioxidant enzyme activity and high proline and soluble sugar content. The Na+ metabolism genes expression was higher in transgenic plants than the WT. The SlTpx transgenic plants showed higher tolerance to H2O2 and MV treatment, compared with the WT. Besides, the growth of prokaryotic strain of SlTpx was better than the pET28a strain with H2O2 treatment. The above results indicate that the SlTpx gene improves the plant salt tolerance by scaveging H2O2.

S-nitrosylation, the addition of nitric oxide (NO) moiety to a reactive cysteine thiol, to form an S-nitrosothiol (SNO), is emerging as a prototypic redox-based post-translational modification. S-nitrosoglutathione reductase (GSNOR) is thought to be the major regulator of total cellular SNO levels in plants. However, its role in excess nitrate stress has not been investigated in spinach. In this study, a spinach GSNOR gene (GenBank Accession No. KR381778) was amplified and designated as SoGSNOR. The transcript and protein level of SoGSNOR were reduced after excess nitrate treatment for 24 h. Addition of NO donor to the nitrate solution decreased the SoGSNOR expression, while supplementation inhibitor of nitrate reductase and nitric oxide synthase increased its expression. Overexpression of SoGSNOR in tobacco increased the germination rate of transgenic seeds, compared to the wild type (WT) under nitrate stress. Higher photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency and expression level of some stress-related genes were detected in the transgenic seedlings than the WT under nitrate stress. The transgenic tobacco seedlings have lower malondialdehyde content, reactive oxygen species (ROS) fluorescence, and higher activities and transcript level of superoxide dismutase, catalase, peroxidase under nitrate stress. SoGSNOR transgenic tobacco plants have lower NR activity and protein level, higher GSNOR and non-symbiotic class 1 hemoglobin (nsHb) protein level than the WT plants, leading to lower NO accumulation and SNOs contents under nitrate stress. These results suggested that overexpression of SoGSNOR increased nitrate stress tolerance of tobacco by regulating ROS and RNS metabolism. A spinach S-nitrosoglutathione reductase (SoGSNOR) gene was isolated from spinach root. The expression level and activities of SoGSNOR were reduced by excess nitrate treatment. Overexpression of SoGSNOR in tobacco increased nitrate stress tolerance by regulating ROS and RNS metabolism.

Aluminum (Al) toxicity is one of the most important limiting factors for crop yield in acidic soils. Bound Al gets converted into a toxic ionic state (Al3+) in acidic soil. Recent studies have shown that Al can act on the cell walls, cell membranes, organelles, and nuclei of microorganisms and affect substance and energy metabolism. To explore the gene expression at the transcriptional level under Al stress, we sequenced the transcriptome of Cryptococcus humicola, which is a highly Al-resistant yeast strain isolated from acidic soil and tolerates up to 200 mM Al3+. The screening conditions for genes from the control and experimental group were a false discovery rate (FDR) 1. A total of 4760 genes were differentially expressed, among which 3066 were upregulated and 1694 were downregulated. These genes control glycometabolism, protein synthesis, lipid metabolism and signalling pathways. Eleven selected differentially expressed genes were further validated using qRT-PCR. The results suggested that Al stress leads to complex responses in C. humicola. The effects of Al on the β-d-glucan and mannose contents and Al accumulation in the cell wall were determined. With an increase in the Al treatment time and concentration, the contents of β-d-glucan and mannose showed a trend of first increasing and then decreasing. Under Al treatment, the Al content of the cell wall also showed a trend of first increasing and then decreasing. These results suggested that Al accumulates in the cell wall and the cell wall plays a vital role in the Al resistance of C. humicola. The differentially expressed genes provide a foundation for the further study of Al tolerance in C. humicola.

Phytotoxicity reduction is one of the main aims of reusing walnut green husk (WGH) for cultivation purposes. This study was conducted to evaluate the efficiency of bio-detoxification by selected Trametes and Schizophyllum strains under solid-state fermentation. Ninety-two isolates of filamentous fungi were obtained from forest litter, and nine strains belonging to Trametes and Schizophyllum genus were selected due to their efficient laccase production and rapid growth using WGH and corncob (w/w, 1:1) as the carbon source under solid-state fermentation. Further, enzyme activities and phytotoxicity assays showed that water extract of WGH treated by Trametes strains 120301, 10288, and 10306 showed a vast lignocellulose enzyme system, higher laccase activity (about 620 U/g), and maximal germination rate (100%), compared with 20% germination rate of the untreated extract of WGH. Our results indicated that Trametes strains are suitable for the phytotoxicity reduction of WGH and laccase production, and showed the possible role of laccase in the detoxification of agricultural wastes rich in phenols such as WGH.

Manganese peroxidases (MnPs), gene family members of white-rot fungi, are necessary extracellular enzymes that degrade lignocellulose and xenobiotic aromatic pollutants. However, very little is known about the diversity and expression patterns of the MnP gene family in white-rot fungi, especially in contrast to laccases. Here, the gene and protein sequences of eight unique MnP genes of T. trogii S0301 were characterized. Based on the characteristics of gene sequence, all TtMnPs here belong to short-type hybrid MnP (type I) with an average protein length of 363 amino acids, 5–6 introns, and the presence of conserved cysteine residues. Furthermore, analysis of MnP activity showed that metal ions (Mn2+ and Cu2+) and static liquid culture significantly influenced MnP activity. A maximum MnP activity (>14.0 U/mL) toward 2,6-DMP was observed in static liquid culture after the addition of Mn2+ (1 mM) or Cu2+ (0.2 or 2 mM). Moreover, qPCR analysis showed that Mn2+ obviously upregulated the Group I MnP subfamily (T_trogii_09901, 09904, 09903, and 09906), while Cu2+ and H2O2, along with changing temperatures, mainly induced the Group II MnP subfamily (T_trogii_11984, 11971, 11985, and 11983), suggesting diverse functions of fungal MnPs in growth and development, stress response, etc. Our studies here systematically analyzed the gene structure, expression, and regulation of the TtMnP gene family in T. trogii, one of the important lignocellulose-degrading fungi, and these results extended our understanding of the diversity of the MnP gene family and helped to improve MnP production and appilications of Trametes strains and other white-rot fungi.

Phenolic glycosides are the important bioactive molecules, and their bioavailability can be influenced by enzyme hydrolysis, such as β-glucosidases (EC3.2.1.21) and other glycosyl hydrolases (GHs). Wood rotting fungi possess a superfamily of GHs, but little attention has been paid to the GHs and their potential applications in biotransformation of phenolic glycosides. In this study, two GH3 gene family members of

White-rot fungi, especially Trametes strains, are the primary source of industrial laccases in bioenergy and bioremediation. Trametes strains express members of the laccase gene family with different physicochemical properties and expression patterns. However, the literature on the expression pattern of the laccase gene family in Trametes trogii S0301 and the response mechanism to Cu(2+), a key laccase inducer, in white-rot fungal strains is scarce. In the present study, we found that Cu(2+) could induce the mRNAs and proteins of the two alternative splicing variants of heat shock transcription factor 2 (TtHSF2). Furthermore, the overexpression of alternative splicing variants TtHSF2α and TtHSF2β-I in the homokaryotic T. trogii S0301 strain showed opposite effects on the extracellular total laccase activity, with maximum laccase activities of approximately 0.6 and 3.0 U ml(−1), respectively, on day 8, which are 0.4 and 2.3 times that of the wild-type strain. Similarly, TtHSF2α and TtHSF2β-I play opposite roles in the oxidation tolerance to H(2)O(2). In addition, the direct binding of TtHSF2α to the promoter regions of the representative laccase isoenzymes (TtLac1 and TtLac13) and protein-protein interactions between TtHSF2α and TtHSF2β-I were detected. Our results demonstrate the crucial roles of TtHSF2 and its alternative splicing variants in response to Cu(2+). We believe that these findings will deepen our understanding of alternative splicing of heat shock transcription factors (HSFs) and their regulatory mechanism of the laccase gene family in white-rot fungi. IMPORTANCE The members of laccase gene family in Trametes strains are the primary source of industrial laccase and have gained widespread attention. Increasing the yield and enzymatic properties of laccase through various methods has always been a topic worthy of attention, and there is no report on the regulation of laccase expression through HSF transcription factor engineering. Here, we found that two alternative splicing variants of TtHSF2 functioned oppositely in regulating the expression of laccase genes, and copper can induce the expression of almost all members of the laccase gene family. Most importantly, our study suggested that TtHSF2 and its alternative splicing variants are vital for copper-induced production of laccases in T. trogii S0301.

Nitrogen (N) is one of the essential macronutrients that plays important roles in plant growth and development. To better understand the response of antioxidant system and N metabolism under N starvation and re-supply condition, physiological and transcriptomic analysis were performed in tomato roots. The malondialdehyde (MDA) and reactive oxygen species (ROS) contents increased significantly in tomato seedlings after N starvation for 24 h. The activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDHAR), the ratio of ASA/DHA and GSH/GSSG, the NO3- contents, nitrate reductase (NR) activity were decreased after N starvation treatment and increased after N re-supply for 24 h. Compared with the control, 1766 genes were up-regulated and 2244 genes were down-regulated after N starvation in tomato. These differentially expressed genes (DEGs) are mainly enriched in functional items such as cellular process, metabolic process and catalytic activity. The KEGG pathways revealed that the DEGs were mainly involved in phenpropane biosynthesis, amino sugar and nucleotide sugar metabolism, and N metabolism. The expression patterns of tomato SlSOD, SlCAT, SlAPX, SlMDHAR, thioredoxin (SlTrxh), peroxiredoxin (SlPrx) and glutaredoxin (SlGrx) genes, and nitrate transporter SlNRT2.4, SlNR, glutamine synthetase (SlGS2), nitrite reductase (SlNiR) decreased after N starvation and increased after N re-supply, which were validated by qRT-PCR. Our results provide a basis for understanding the response of tomato to N deficiency and re-supply and a theoretical reference for cultivation regulation.

Aluminum (Al) toxicity is one of the most important limiting factors for crop yield in acidic soils. Bound Al gets converted into a toxic ionic state (Al3+) in acidic soil. Recent studies have shown that Al can act on the cell walls, cell membranes, organelles, and nuclei of microorganisms and affect substance and energy metabolism. To explore the gene expression at the transcriptional level under Al stress, we sequenced the transcriptome of Cryptococcus humicola, which is a highly Al-resistant yeast strain isolated from acidic soil and tolerates up to 200 mM Al3+. The screening conditions for genes from the control and experimental group were a false discovery rate (FDR)0.05 and log 2|FC|1. A total of 4760 genes were differentially expressed, among which 3066 were upregulated and 1694 were downregulated. These genes control glycometabolism, protein synthesis, lipid metabolism and signalling pathways. Eleven selected differentially expressed genes were further validated using qRT-PCR. The results suggested that Al stress leads to complex responses in C. humicola. The effects of Al on the β-d-glucan and mannose contents and Al accumulation in the cell wall were determined. With an increase in the Al treatment time and concentration, the contents of β-d-glucan and mannose showed a trend of first increasing and then decreasing. Under Al treatment, the Al content of the cell wall also showed a trend of first increasing and then decreasing. These results suggested that Al accumulates in the cell wall and the cell wall plays a vital role in the Al resistance of C. humicola. The differentially expressed genes provide a foundation for the further study of Al tolerance in C. humicola.

A thermo-activation and thermostable laccase isoenzyme (Lac 37 II) produced by Trametes trogii S0301 at 37°C was purified to apparent homogeneity by anionic exchange chromatography and sephadex G-75 chromatography, with 12.3% of yeiled and a specific activity of 343.1 U mg-1. The molecular weight of the purified Lac 37 II was estimated to be approximately 56 kDa in 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The optimal pH and temperature for the protein was 2.7 and 60°C, respectively. The purified Lac 37 II showed higher resistance to all tested metal ions and organic solvents except for Fe2+ and Cd2+ at 37°C and the activity of the purified Lac 37 was significantly enhanced by Cu2+ at 50 mM. The K cat , K m , and K cat /K m of Lac 37 II were 2.977 s-1, 16.1 μM, and 184.9 s-1 μM-1, respecively, in the condition of pH 2.7 and 60°C using ABTS as a substrate. Peptide-mass fingerprinting analysis showed that the Lac 37 II matched to the gene-deduced sequences of lcc3 in T. trogii BAFC 463, other than Lcc1, Lcc 2, and Lcc 4. Compared with laccase prepared at 28°C, the onset of thermo-activation of Lac 37 II activity occurred at 30°C with an increase of 10%, and reached its maximum at the temperatures range of 40-60°C with an increase of about 40% of their original activity. Furthermore, Lac 37 II showed the efficient decolorization ability toward triphenylmethane dyes at 60°C, with decolorization rates of 100 and 99.1% for 25 mg L-1 malachite and crystal violet in 5 h, respectively, when hydroxybenzotriazole (HBT) was used as a mediator. In conclusion, it is the first time to report a thermo-activation laccase from a thermophilic T. trogii strain, which has a better enzyme property and higher decolorization ability among fungal laccases, and it also has a further application prospective in the field of biotechnology.

The thioredoxin (Trx) system plays a vital function in cellular antioxidative defense. However, little is known about Trx in tomato under excess nitrate. In this study, we isolated the tomato gene encoding h-type Trx gene (SlTrxh). The mRNA transcript of SlTrxh in roots and leaves of tomato was induced incrementally under excess nitrate for 24 h. Subcellular localization showed that SlTrxh might localize in the cytoplasm, nucleus and plasma membrane. Enzymatic activity characterization revealed that SlTrxh protein possesses the disulfide reductase function and Cysteine (Cys) 54 is important for its activity. Overexpressing SlTrxh in tobacco resulted in increasing seed germination rate, root length and decreasing H2O2 and O2− accumulation, compared with the wild type (WT) tobacco under nitrate stress. While overexpressing SlTrxhC54S (Cysteine 54 mutated to Serine) in tobacco showed decreased germination rate and root length compared with the WT after nitrate treatment. After nitrate stress treatment, SlTrxh overexpressing transgenic tobacco plants have lower malonaldehyde (MDA), H2O2 contents and Reactive Oxygen Species (ROS) accumulation, and higher mRNA transcript level of NtP5CS, NtDREB2, higher ratio of ASA/DHA and GSH/GSSG, higher activities of ascorbate peroxidase and NADP thioredoxin reductase. Besides, SlTrxh overexpressing plants showed higher tolerance to Methyl Viologen (MV) in the seed germination and seedling stage. The yeast two-hybrid, pull-down, Co-immunoprecipitation and Bimolecular luciferase complementation assay confirmed that SlTrxh physically interacted with tomato peroxiredoxin (SlPrx). These results suggest that SlTrxh contributes to maintaining ROS homeostasis under excess nitrate stress interacting with SlPrx and Cys54 is important for its enzyme activity.

Summary Endophytic fungal communities of Dysphania ambrosioides, a hyperaccumulator growing at two Pb‐Zn‐contaminated sites, were investigated through culture‐dependent and culture‐independent approaches. A total of 237 culturable endophytic fungi (EF) were isolated from 368 tissue (shoot and roots) segments, and the colonization rate (CR) ranged from 9.64% to 65.98%. The isolates were identified to 43 taxa based on morphological characteristics and rDNA ITS sequence analysis. Among them, 13 taxa (30.23%) were common in plant tissues from both sites; however, dominant EF were dissimilar. In culture‐dependent study, 1989 OTUs were obtained through Illumina Miseq sequencing, and dominant EF were almost same in plant tissues from both sites. However, some culturable EF were not observed in total endophytic communities. We suggest that combination of both culture‐dependent and culture‐independent methods will provide more chances for the precise estimation of endophytic fungal community than using either of them. The tissue had more influence on the culturable fungal community structure, whereas the location had more influence on the total fungal community structure (including culturable and unculturable). Both culture‐dependent and culture‐independent studies illustrated that endophytic fungal communities of D. ambrosioides varied across the sites, which suggested that HM concentration of the soil may have some influence on endophytic fungal diversity.

Alginate lyases degrade alginate in a beta-elimination reaction to produce oligosaccharides. Thus, alginate lyases are widely used in the food/pharmaceutical industries and are commercially valuable. In this study, four alginate lyase encoding genes were successfully cloned from Sphingomonas sp. ZH0. The expression systems of these alginate lyases were then constructed in Escherichia coli cells. The recombinant ZH0-I, ZH0-II, ZH0-III and ZH0-IV were purified from E. coli cells and were confirmed to be monomeric enzymes with molecular weights of approximately 91, 52, 67, and 113 kDa, respectively. The conditions for enzymes to have the highest specific lyase activities were 53.2 U/mg, 42 °C, pH 7.0 for ZH0-I, 103.9 U/mg, 47 °C, pH 6.5 for ZH0-II, 13.7 U/mg, 52 °C, pH 7.5 for ZH0-III, and 12.3 U/mg, 37 °C, pH 7.0 for ZH0-IV, respectively. These recombinant enzymes were stable over a pH range. Moreover, the enzymes were active in the absence of salt ions, and their activities were substantially reduced by the addition of HgCl2. ZH0-I, ZH0-II and ZH0-III belong to endotype alginate lyases, while ZH0-IV is an exotype alginate lyase. All types could degrade both poly-β- d -mannuronate and poly-α- l -guluronate blocks, yielding alginate oligosaccharides as the main product. The Km and Vmax values were 0.51 mg/ml and 56.18 U/ml for ZH0-I, 0.47 mg/ml and 27.5 U/ml for ZH0-II, 0.55 mg/ml and 60.24 U/ml for ZH0-III, and 0.41 mg/ml and 5.53 U/ml for ZH0-IV, respectively. These features indicate that these alginate lyases are promising candidates for producing antioxidants from alginates in industrial applications.

Soil secondary salinization caused by excess nitrate addition is one of the major obstacles in greenhouse vegetable production. Excess nitrate inhibited the growth of tomato plants, while application of 100 μM H2S donor NaHS efficiently increased the plant height, fresh and dry weight of shoot and root, root length, endogenous H2S contents and L-cysteine desulfhydrases activities. NaHS altered the oxidative status of nitrate-stressed plants as inferred by changes in reactive oxygen species (ROS) accumulation and lipid peroxidation accompanied by regulation of the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX). Besides, NaHS increased the nitric oxide (NO) and total S-nitrosothiols (SNOs) contents, nitrate reductase (NR) activities and decreased the S-nitrosoglutathione reductase (GSNOR) activities under nitrate stress. Furthermore, microarray analysis using the Affymetrix Tomato GeneChip showed that 5349 transcripts were up-regulated and 5536 transcripts were down-regulated under NaHS and excess nitrate stress treatment, compared to the excess nitrate stress alone. The differentially expressed genes (log2 fold change >2 or

Based on the periodic and repetitive characteristics of partial discharge (PD) under power frequency voltage, an ultra-high-frequency (UHF) PD measurement system using scanning and comparing method is realized without analog to digital (A/D) acquisition. The UHF PD pulses are compared with adjustable reference levels by high-speed comparator, and the number of pulses higher than the reference levels is recorded by a field programmable gate array (FPGA) along with corresponding phase information. The phases, amplitudes and number of discharge pulses can be extracted from the acquired data, which is verified in needle-plate PD experiment result analysis. And PD spectrograms of proposed method proves to be highly correlated with that of pulse current method and conditional UHF method. Influence factors in PD signal acquisition process are also analyzed.

There has been continued interest in bacteriocins research from an applied perspective as bacteriocins have potential to be used as natural preservative. Four bacteriocinogenic lactic acid bacteria (LAB) strains of Lactobacillus curvatus (Arla-10), Enterococcus faecium (JFR-1), Lactobacillus paracasei subsp. paracasei (JFR-5) and Streptococcus thermophilus (TSB-8) were previously isolated and identified in our lab. The objective of this study was to determine the optimal growth conditions for both LAB growth and bacteriocins production. In this study, various growth conditions including culture media (MRS and BHI), initial pH of culture media (4.5, 5.5, 6.2, 7.4 and 8.5), and incubation temperatures (20, 37 and 44 °C) were investigated for LAB growth measured as optical density (OD), bacteriocin activity determined as arbitrary unit and viability of LAB expressed as log CFU ml−1. Growth curves of the bacteriocinogenic LAB were generated using a Bioscreen C. Our results indicated that Arla-10, JFR-1, and JFR-5 strains grew well on both MRS and BHI media at growth temperature tested whereas TSB-8 strain, unable to grow at 20 °C. LAB growth was significantly affected by the initial pH of culture media (p

As a signal molecule, hydrogen sulfide (H2S) plays an important role in plant growth. In this study, the effect of different concentration of H2S donor, sodium hydrosulfide (NaHS), on growth of tomato seedlings was tested in hydroponic culture. The effects of 50 μM NaHS on tomato seedlings were not significant, compared with the control. After 100 μM NaHS treatment, plant height, shoot fresh weight and dry weight increased significantly. However, 300, 500 and 1000 μM NaHS had inhibitory effect on tomato seedlings, especially 1000 μM NaHS. 100 μM NaHS could increase chlorophyll a, chlorophyll b, and total chlorophyll content, stomatal conductance, net photosynthetic rate, transpiration rate and intercellular CO2 concentration. The activities of nitrate reductase, glutamate synthase and glutamine synthase, and L-cysteine demethylase (LCD), and nitrate content, were increased significantly after 100 μM NaHS treatment. The microarray results showed that 9122 genes changed after treated with 100 μM NaHS for 3 h, and 430 genes changed more than 2 times. These genes were grouped into metabolism, signal transduction, stress resistance, transcription factors, transport, protein synthesis and degradation, hormone response, and cell wall related genes in tomato seedlings. RT-PCR analysis showed that the expression of some MAPK family genes changed significantly when exogenous NaHS was added, especially SlMAPK3 and SlMAPK13. The MAPK inhibitor PD98059 reduce the LCD activity and H2S content in tomato seedlings, which indicated that MAPK signaling pathway was involved in the process of H2S promoting tomato seedling growth.

Background Trametes trogii is a member of the white-rot fungi family, which has a unique ability to break down recalcitrant lignin polymers to CO2 and water, and they have enormous potential to biodegrade a wide range of toxic environmental pollutants. Because of its industrial potential, the identification of lignin-degrading enzyme systems in Trametes is an important area of research. Development and utilization of industrial value genes are suffering due to deficiency knowledge of genome available for their manipulation. Results In the present study, Homokaryotic strains of T. trogii S0301 were screened and sequencing by PacBio Sequel II platform. The final draft genome is ~ 39.88 Mb, with a contig N50 size of 2.4 Mb, this was the first genome sequencing and assembly of T. trogii species. Further analyses predicted 14,508 protein-coding genes. Results showed that T. trogii S0301 contains 602 genes encoding CAZymes, include 211 glycoside hydrolase and 117 lignin-degrading family genes, nine laccases related genes. Small subunit ribosomal RNA gene (18S rRNA) sequencing confirms its phylogenetic position. Moreover, T. trogii S0301 has the largest number of cytochromes P450 (CYPs) superfamily genes compare to other fungi. All these results are consistent with enzymatic assays and transcriptome analysis results. We also analyzed other genome characteristics in the T. trogii S0301genome. Conclusion Here, we present a nearly complete genome for T. trogii S0301, which will help elucidate the biosynthetic pathways of the lignin-degrading enzyme, advancing the discovery, characterization, and modification of novel enzymes from this genus. This genome sequence will provide a valuable reference for the investigation of lignin degradation in the Trametes genus.

A thermo-activation and thermostable laccase isoenzyme (Lac 37 II) produced by Trametes trogii S0301 at 37°C was purified to apparent homogeneity by anionic exchange chromatography and sephadex G-75 chromatography, with 12.3% of yeiled and a specific activity of 343.1 U mg–1. The molecular weight of the purified Lac 37 II was estimated to be approximately 56 kDa in 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The optimal pH and temperature for the protein was 2.7 and 60°C, respectively. The purified Lac 37 II showed higher resistance to all tested metal ions and organic solvents except for Fe2+ and Cd2+ at 37°C and the activity of the purified Lac 37 was significantly enhanced by Cu2+ at 50 mM. The Kcat, Km, and Kcat/Km of Lac 37 II were 2.977 s–1, 16.1 μM, and 184.9 s–1 μM–1, respecively, in the condition of pH 2.7 and 60°C using ABTS as a substrate. Peptide-mass fingerprinting analysis showed that the Lac 37 II matched to the gene-deduced sequences of lcc3 in T. trogii BAFC 463, other than Lcc1, Lcc 2, and Lcc 4. Compared with laccase prepared at 28°C, the onset of thermo-activation of Lac 37 II activity occurred at 30°C with an increase of 10%, and reached its maximum at the temperatures range of 40–60°C with an increase of about 40% of their original activity. Furthermore, Lac 37 II showed the efficient decolorization ability toward triphenylmethane dyes at 60°C, with decolorization rates of 100 and 99.1% for 25 mg L–1 malachite and crystal violet in 5 h, respectively, when hydroxybenzotriazole (HBT) was used as a mediator. In conclusion, it is the first time to report a thermo-activation laccase from a thermophilic T. trogii strain, which has a better enzyme property and higher decolorization ability among fungal laccases, and it also has a further application prospective in the field of biotechnology.

Additional file 6. BUSCO validation of the T. trogii S0301 genome annotation result.

Additional file 5. Gene annotation of the T. trogii S0301 genome.

Additional file 1. Genome comparisons with other Trametes species.

Additional file 9. Repeats content of the T. trogii S0301 genome.

SummaryIn this study, the effects of the exogenous H2S donor, NaHS, on the germination of tomato seeds under nitrate (NO3 -) ion stress were investigated. The results showed that under increased nitrate ion stress (range 0 - 200 mM), the germination percentage of tomato seeds decreased from 92.3% to 1.0%. The application of NaHS, up to 100 ?M, alleviated the inhibitory effect of nitrate stress by enhancing seed germination up to 1.3-fold compared to the nitrate stress treatment alone. Further study showed that malondialdehyde concentrations and the accumulation of reactive oxygen species declined significantly after all NaHS treatments. Amylase, superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase activities increased significantly after 100 ?M NaHS treatment. In addition, nitric oxide (NO) fluorescence increased when NaHS was added to the nitrate solution. Our results suggest that exogenous H2S can alleviate the damage caused by nitrate stress, possibly through increasing anti-oxidant enz...

Soil secondary salinization caused by excess nitrate addition is one of the major obstacles in greenhouse vegetable production. Excess nitrate inhibited the growth of tomato plants, while application of 100 μM H

Using response surface methodology, the maximum laccase activity of 122.9 U ml −1 was obtained in Trametes trogii S0301. The major isoform of the laccase secreted in the optimized medium was purified by 4-fold to a specific activity of 352.1 U mg −1 protein. The laccase (a molecular mass of 56 kDa), acted optimally at pH 3.0 and exhibited an optimum temperature of 45 °C using ABTS as substrate, with the half-life at 60 °C and 75 °C for 3 h and 10 min, respectively. The purified laccase was highly resistant to Co 2+ , Cu 2+ , Zn 2+ and Mn 2+ (100 mM). In addition, the purified laccase was effective to decolorize malachite green, bromophenol blue, crystal violet and acid red without the addition of redox mediators. Peptide-mass fingerprinting analysis by MALDI-TOF MS showed the purified laccase of T. trogii S0301 was a typical laccase isoform, which shared 99.3% identity with a laccase from Coriolopsis gallica . Further, the full-length DNA of the laccase was cloned based on the highly conservative copper-binding domains using degenerate PCR and TAIL-PCR, and the deduced amino acid sequence of the matured protein matched exactly with the peptides of the purified laccase.

Formaldehyde (HCHO) is a major indoor air pollutant. Plants can be used to remove HCHO from polluted air because they can use HCHO as a carbon source to incorporate it into one-carbon (C1) metabolism. However, high concentrations of exogenous HCHO cause damages to plants. Therefore, genetic engineering is an effective measure to improve ability of plants to clear the HCHO pollution. Expression of AtHsfA1d encoding heat shock transcription factor of Arabidopsis was induced by HCHO stress. AtHsfA1d was cloned into the pYES3 vector and transformed into Saccharomyces cerevisiae. Yeast cells expression of AtHSFA1d showed higher tolerance to HCHO stress than wild-type (WT) cells. AtHsfA1d was introduced into tobacco and the expression of AtHSFA1d in transgenic lines was demonstrated using Western blot analysis. Transgenic tobacco showed higher uptake rate to aqueous HCHO, had the higher biomass and produced higher content of total proteins than WT plants. These results indicated that AtHsfA1d conferred HCHO tolerance to yeast and tobacco. AtHsfA1d is a good candidate to develop phytoremediation plants for HCHO pollution.

Trametes (synonym Coriolous) species are the most important sources for laccases with attractive properties. Several Trametes species were screened for their ability to produce laccase and decolorize malachite green (MG). Trametes trogii Berk S0301 was chosen for further study because it showed the highest 2,2′-azino bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) oxidization ability, which is closely correlated with MG decolorization. The laccase activity of T. trogii Berk S0301 was enhanced up to 34.3-fold and 5.6-fold by Cu2+ (1.5 mM) and Tween 80 (7 g L−1), respectively. Mn2+, Mg2+, Zn2+, Co2+ and Na+ (100 mM) only slightly (less than 10% inhibition) affected MG decolorization by the crude laccase of T. trogii Berk S0301. MG was decolorized effectively at pH 4.5–7.0 and 30–80 °C with an optimum decolorization at pH 6 and 50–70 °C. Phyto- and micro-toxicity tests revealed that less toxic metabolites were formed after laccase treatment. The present work demonstrates that strain T. trogii Berk S0301 and its laccase may facilitate novel and more efficient bio-catalytic process applications.

The diversity and plant growth-promoting ability of endophytic fungi associated with the five flower plant species growing in Yunnan, Southwest China, were investigated. A total of 357 culturable endophytic fungi were isolated from 1000 segments of healthy leaves and stems of the five plant species. Based on the morphological characteristics and the rDNA internal transcribed spacer (ITS) analysis, the isolates were identified to 24 taxa, of which Alternaria, Phomopsis, Cladosporium, and Colletotrichum were the dominant genera. The Sorenson's coefficient similarity indices of the endophytic fungi from the five flower plant species ranged from 0.36 to 0.80. It was found that the similarity index between two cultivated flowers (0.8) or the similarity index between two wild flowers (0.71–0.76) was higher than the similarity index between one cultivated flower and one wild flower (0.36–0.48). The Shannon indices (H) of the endophytic fungi from the five plant species ranged from 1.73 to 2.45, and the diversity...

A class 1 non-symbiotic hemoglobin family gene, SoHb, was isolated from spinach. qRT-PCR showed that SoHb was induced by excess nitrate, polyethylene glycol, NaCl, H2O2, and salicylic acid. Besides, SoHb was strongly induced by application of nitric oxide (NO) donor, while was suppressed by NO scavenger, nitrate reductase inhibitor, and nitric oxide synthase inhibitor. Overexpression of SoHb in Arabidopsis resulted in decreased NO level and sensitivity to nitrate stress, as shown by reduced root length, fresh weight, the maximum photosystem II quantum ratio of variable to maximum fluorescence (Fv/Fm), and higher malondialdehyde contents. The activities and gene transcription of superoxide dioxidase, and catalase decreased under nitrate stress. Expression levels of RD22, RD29A, DREB2A, and P5CS1 decreased after nitrate treatment in SoHb-overexpressing plants, while increased in the WT plants. Moreover, SoHb-overexpressing plants showed decreased tolerance to NaCl and osmotic stress. In addition, the SoHb-overexpression lines showed earlier flower by regulating the expression of SOC, GI and FLC genes. Our results indicated that the decreasing NO content in Arabidopsis by overexpressing SoHb might be responsible for lowered tolerance to nitrate and other abiotic stresses.

In this article, silver nanoparticles inlaid Fe 3 O 4 –SiO 2 magnetic composite (Fe 3 O 4 –SiO 2 –Ag) was successfully synthesized and its potential application as an antibacterial material in water disinfection was investigated. Silver nanoparticles, with diameter of about 10 nm, were anchored homogeneously and tightly onto the silica coat of Fe 3 O 4 –SiO 2 magnetic nanoparticles, which increased the antibacterial abilities by avoiding the aggregation of Ag nanoparticles. The minimum inhibitory concentrations of Fe 3 O 4 –SiO 2 –Ag magnetic composite to Escherichia coli and Staphylococcus aureus were 15.625 mg L −1 and 31.25 mg L −1 , respectively, and the minimum bactericidal concentrations were 250 mg L −1 and 500 mg L −1 , respectively. In inactivation experiment, 150 mg L −1 of Fe 3 O 4 –SiO 2 –Ag disinfectant in 150 mL of normal saline solution could kill 99.9% of the tested bacteria within 60 min. Paper disk diffusion assay also showed excellent antibacterial abilities to both E. coli and S. aureus . The silica coat not only acted as a supporting matrix, but also enhanced the stability of the disinfectant. The obtained Fe 3 O 4 –SiO 2 –Ag composite has a high magnetic saturation value of 75 emu g −1 , which indicates that the composite can be recovered from water solution for reuse through magnetic separation and the waste and possible contamination of disinfectant to environment are avoided.

In this study, bioethanol production from NaOH/H2O2-pretreated water hyacinth was investigated. Pretreatment of water hyacinth with 1.5% (v/v) H2O2 and 3% (w/v) NaOH at 25 °C increased the production of reducing sugars (223.53 mg/g dry) and decreased the cellulose crystallinity (12.18%), compared with 48.67 mg/g dry and 22.80% in the untreated sample, respectively. The newly isolated Kluyveromyces marxianu K213 showed greater ethanol production from glucose (0.43 g/g glucose) at 45 °C than did the control Saccharomyces cerevisiae angel yeast. The maximum ethanol concentration (7.34 g/L) achieved with K. marxianu K213 by simultaneous saccharification and fermentation (SSF) from pretreated water hyacinth at 42 °C was 1.78-fold greater than that produced by angel yeast S. cerevisiae at 30 °C. The present work demonstrates that bioethanol production achieved via SSF of NaOH/H2O2-pretreated water hyacinth with K. marxianu K213 is a promising strategy to utilize water hyacinth biomass.

This paper proposes a novel UHF PD monitoring system, which is based on the scanning and comparing method. It does not need to record the complete signal waveform. This system is constituted by the high-frequency filter and amplifier, the field programmable gate array and high-frequency comparator, which realizes signal digitizing in-field and the partial discharge features extraction, and transmits data to the host computer via Ethernet. This paper describes the basic principle and components of the UHF Scanning System, and the detected signal is analyzed too. And PD is detected using this UHF monitoring system in the laboratory and field. Experiments and field results show that in addition to the PD characteristic parameters can be obtained, the system can extract spectrum and real-time monitor PD phenomena.

Four series (S, M, R, and W) of Alternaria longipes isolates were obtained based on consecutive induction with Dimethachlon (Dim) and ultraviolet irradiation. These isolates were then characterized according to their tolerance to Dim, sensitivity to osmotic stress, and phenotypic properties. All the induced Dim-resistant isolates showed a higher osmosensitivity than the parental strains, and the last generation was more resistant than the first generation in the M, R, and W series. In addition, the changes in the Dim resistance and osmotic sensitivity were not found to be directly correlated, and no distinct morphologic characteristics were found among the resistant and sensitive isolates, with the exception of the resistant isolate K-11. Thus, to investigate the molecular basis of the fungicide resistance, a group III two-component histidine kinase (HK) gene, AlHK1, was cloned from nineteen A. longipes isolates. AlHK1p was found to be comprised of a six 92- amino-acid repeat domain (AARD), HK domain, and response regulator domain, similar to the Os-1p from Neurospora crassa. A comparison of the nucleotide sequences of the AlHK1 gene from the Dim-sensitive and -resistant isolates revealed that all the resistant isolates contained a single-point mutation in the AARD of AlHK1p, with the exception of isolate K-11, where the AlHK1p contained a deletion of 107 amino acids. Moreover, the AlHK1p mutations in the isolates of each respective series involved the same amino acid substitution at the same site, although the resistance levels differed significantly in each series. Therefore, these findings suggested that a mutation in the AARD of AlHK1p was not the sole factor responsible for A. longipes resistance to dicarboximide fungicides.