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The gearbox is an important component of the system of high-speed trains, which is susceptible to damage and failure due to the long-term high-speed and heavy-load working environment, so it is important to diagnose the faults of high-speed train gearboxes quickly and accurately. Thus, based on analysis of the structure type and common faults of the EMU gearbox, the current application status of the typical technologies such as vibration analysis, noise analysis, temperature field analysis, oil analysis and acoustic emission used for fault diagnosis of the EMU gearbox at home and abroad is explained, the applicability of these technologies is analyzed and key research directions are proposed. The analysis results show that the current multiple fault diagnosis technologies applied in high-speed EMU gearboxes have their own advantages, disadvantages and application occasions. The single diagnosis technology can not accurately diagnose the multi-type failures of the gearbox due to its limitations, and the fusion of multiple techniques based on advanced intelligent algorithms is expected to be one of the research focuses for fault diagnosis in this field in the future.

To improve the quality of summer-autumn tea, the fermentation of summer-autumn tea was investigated by using Eurotium cristatum. The contents of tea polyphenols, total free amino acids, total flavonoids, water leachate, and sensory scores of summer-autumn tea were used as the indicators for the one-way experiment, and four factors and three levels were selected for orthogonal experiments to optimize the fermentation process. The volatile compounds of fermented summer-autumn tea under the optimal process were analyzed by gas chromatography-mass spectrometry (GC-MS) technology. The results showed that the optimal fermentation process was 30% water content, 15% inoculum of Eurotium cristatum, fermentation time of 9 d, and fermentation temperature of 30 °C, and the water leachate content of summer-autumn tea processed under these conditions was significantly increased by 22.51% (P<0.05), the tea polyphenol content was significantly decreased by 27.71% (P<0.05), and the total flavonoid content was significantly decreased by 6.41% (P<0.01), free amino acids did not change significantly, and the sensory score was significantly improved by 10.33 points (P<0.01). In addition, the total amount of flavor compounds was elevated by 296.76% after fermentation, and the content of linalool, linalool oxide I, α-Terpineol, methyl salicylate, and phenethyl acetate substances increased especially significantly throughout the fermentation process, which brought rich fruity and floral aroma to the summer-autumn tea. Thus, the overall quality of summer-autumn tea improved after fermentation treatment. [ABSTRACT FROM AUTHOR]

Summary: The clade III subfamily of OsSWEETs includes transmembrane proteins necessary for susceptibility to bacterial blight (BB). These genes are targeted by the specific transcription activator‐like effector (TALE) of Xanthomonas oryzae pv. oryzae and mediate sucrose efflux for bacterial proliferation. However, the mechanism through which OsSWEETs regulate rice immunity has not been fully elucidated. Here, we demonstrated that the cytosolic carboxyl terminus of OsSWEET11a/Xa13 is required for complementing susceptibility to PXO99 in IRBB13 (xa13/xa13). Interestingly, the C‐terminus of ZmXa13, the maize homologue of OsSWEET11a/Xa13, could perfectly substitute for the C‐terminus of OsSWEET11a/Xa13. Furthermore, OsSWEET11a/Xa13 interacted with the high‐mobility group B1 (OsHMGB1) protein and the small heat shock‐like protein OsHsp20L through the same regions in the C‐terminus. Consistent with the physical interactions, knockdown or knockout of either OsHMGB1 or OsHsp20L caused an enhanced PXO99‐resistant phenotype similar to that of OsSWEET11a/OsXa13. Surprisingly, the plants in which OsHMGB1 or OsHsp20L was repressed developed increased resistance to PXO86, PXO61 and YN24, which carry TALEs targeting OsSWEET14/Xa41 or OsSWEET11a/Xa13. Additionally, OsHsp20L can interact with all six members of clade III OsSWEETs, whereas OsHMGB1 can interact with five other members in addition to OsSWEET12. Overall, we revealed that OsHMGB1 and OsHsp20L mediate conserved BB susceptibility by interacting with clade III OsSWEETs, which are candidates for breeding broad‐spectrum disease‐resistant rice. [ABSTRACT FROM AUTHOR]

At present, atmospheric and room‐temperature plasma (ARTP) is regarded as a new and powerful mutagenesis technology with the advantages of environment‐friendliness, operation under mild conditions, and fast mutagenesis speed. Compared with traditional mutagenesis strategies, ARTP is used mainly to change the structure of microbial DNA, enzymes, and proteins through a series of physical, chemical, and electromagnetic effects with the organisms, leading to nucleotide breakage, conversion or inversion, causing various DNA damages, so as to screen out the microbial mutants with better biological characteristics. As a result, in recent years, ARTP mutagenesis and the combination of ARTP with traditional mutagenesis have been widely used in microbiology, showing great potential for application. In this review, the recent progress of ARTP mutagenesis in different application fields and bottlenecks of this technology are systematically summarized, with a view to providing a theoretical basis and technical support for better application. Finally, the outlook of ARTP mutagenesis is presented, and we identify the challenges in the field of microbial mutagenesis by ARTP. Significance statement: The aim of this review is to analyze the beneficial mutagenic effects induced by ARTP on microbial cells and the related mutagenic mechanisms. Subsequently, bottleneck issues and the recent research progress of ARTP on mutagenesis are systematically summarized, and the application prospect is presented. This review may provide valuable insights and research ideas for future atmospheric and room‐temperature plasma mutagenesis of cells. [ABSTRACT FROM AUTHOR]

Abstract A fruity aroma-producing yeast strain was isolated with the aim of improving the aroma of fermented lily rice wine, and identified as Wickerhamomyces anomalus HN006. In addition, the effects of adding solid residues of previous fermentation cycles, and of fungus α-amylase and W. anomalus HN006 supplementation on the biochemical parameters of lily rice wine were evaluated. The optimum quality of the wine, in terms of ethanol and residual sugar content, acidity levels and aroma, was obtained with 5% (w/v) solid residue addition, and supplementation with 10 U/g fungal α-amylase and 2% (v/v) W. anomalus inoculum on the 4th day of fermentation. Volatile compound profiles, the total amount of amino acids and the sensory characteristics of the lily rice wines produced by the two fermentation processes were also evaluated and compared. The lily rice wine obtained from our optimized experimental technology produced higher amounts of some esters, free fatty acids, alcohols, aldehydes, ketones, alkenes, volatile phenol and thiazole, in addition to higher total amino acid content and sensory scores compared to the traditionally brewed wine. Our process resulted in an intensification and improvement of lily rice wine aroma.

Summary: Plants experience numerous biotic stresses throughout their lifespan, such as pathogens and pests, which can substantially affect crop production. In response, plants have evolved various metabolites that help them withstand these stresses. Here, we show that two specialized metabolites in the herbaceous perennial Belamcanda chinensis, tectorigenin and its glycoside tectoridin, have diverse defensive effects against phytopathogenic microorganisms and antifeeding effects against insect pest. We further functionally characterized a 7‐O‐uridine diphosphate glycosyltransferase Bc7OUGT, which catalyses a novel reversible glycosylation of tectorigenin and tectoridin. To elucidate the catalytic mechanisms of Bc7OUGT, we solved its crystal structure in complex with UDP and UDP/tectorigenin respectively. Structural analysis revealed the Bc7OUGT possesses a narrow but novel substrate‐binding pocket made up by plentiful aromatic residues. Further structure‐guided mutagenesis of these residues increased both glycosylation and deglycosylation activities. The catalytic reversibility of Bc7OUGT was also successfully applied in an one‐pot aglycon exchange reaction. Our findings demonstrated the promising biopesticide activity of tectorigenin and its glycosides, and the characterization and mechanistic study of Bc7OUGT could facilitate the design of novel reversible UGTs to produce valuable glycosides with health benefits for both plants and humans. [ABSTRACT FROM AUTHOR]

Downy Mildew Resistance 6-like (DMR6-like) genes are identified as salicylic acid (SA) hydroxylases and negative regulators of plant immunity. Previously, we identified two rice DMR6-like genes, OsF3H03g, and OsF3H04g, that act as susceptible targets of transcription activator-like effectors (TALEs) from Xanthomonas oryzae pv. oryzicola (Xoc), which causes bacterial leaf streak (BLS) in rice. Furthermore, all four homologs of rice DMR6-like proteins were identified to predominantly carry the enzyme activity of SA 5-hydroxylase (S5H), negatively regulate rice broad-spectrum resistance, and cause the loss of function of these OsDMR6s, leading to increased resistance to rice blast and bacterial blight (BB). Here, we curiously found that an OsF3H04g knock-out mutant created by T-DNA insertion, osf3h04g, was remarkedly susceptible to BLS and BB and showed an extreme reduction in SA content. OsF3H04g knock-out rice lines produced by gene-editing were mildly susceptible to BLS and reduced content of SA. To explore the susceptibility mechanism in OsF3H04g loss-of-function rice lines, transcriptome sequencing revealed that another homolog, OsS3H, had induced expression in the loss-of-function OsF3H04g rice lines. Furthermore, we confirmed that a great induction of OsS3H downstream and genomically adjacent to OsF3H04g in osf3h04g was primarily related to the inserted T-DNA carrying quadruple enhancer elements of 35S, while a slight induction was caused by an unknown mechanism in gene-editing lines. Then, we found that the overexpression of OsS3H increased rice susceptibility to BLS, while gene-editing mediated the loss-of-function OsS3H enhanced rice resistance to BLS. However, the knock-out of both OsF3H04g and OsS3H by gene-editing only neutralized rice resistance to BLS. Thus, we concluded that the knock-out of OsF3H04g activated the expression of the OsS3H, partially participating in the susceptibility to BLS in rice. [ABSTRACT FROM AUTHOR]

Background: Exhaled nitric oxide (FeNO) is a simple, noninvasive, and reproducible test, and FeNO (50 ml/s) is often used to reflect airway inflammation. The peripheral small airway/alveolar nitric oxide (NO) concentration is derived from the output of NO at multiple flow rates. Concentration of alveolar NO (CANO), which has been reported to reflect peripheral small airway inflammation, may be related to parameters that reflect abnormal small airway function. Aim: This study aims to investigate the relationship among CANO levels, clinical features, and small airway function‐related indicators in patients with stable asthma and to provide a simple method for monitoring small airway function in asthma. Design and Methods: We recruited 144 patients with well‐controlled, stable asthma, including 69 patients with normal small airway function (normal group) and 75 patients with small airway dysfunction (abnormal group). CANO and pulmonary function were measured. Results: CANO was significantly higher in the abnormal group ([7.28 ± 3.25] ppb) than the normal group CANO ([2.87 ± 1.50] ppb). FEF25–75%pred ([55.0 ± 16.5]%), FEF50%pred ([46.4 ± 13.2]%), and FEF75%pred ([41.9 ± 13.1]%) in abnormal group were significantly lower compared with normal group ([89.9 ± 7.5]%), ([80.9 ± 6.8]%), and ([73.8 ± 5.0]%). CANO was negatively correlated and FEF25–75%pred, FEF50%pred, and FEF75%pred (r = −0.87, P < 0.001; r = −0.82, P < 0.001; r = −0.78, P < 0.001). CANO was positively correlated with age (r = 0.27, P = 0.001). The area under the ROC curve was 0.875 for CANO. The optimal cutoff point of 5.3 ppb had sensitivity and specificity values of 72% and 92% in diagnosing small airway dysfunction. Conclusion: CANO has diagnostic value for small airway dysfunction, and the optimal cutoff value is 5.3 ppb. However, the diagnostic evidence is still insufficient, so it still needs further exploration for its value in detecting small airway dysfunction. [ABSTRACT FROM AUTHOR]

Summary: High temperature causes devasting effects on many aspects of plant cells and thus enhancing plant heat tolerance is critical for crop production. Emerging studies have revealed the important roles of chromatin modifications in heat stress responses. However, how chromatin is regulated during heat stress remains unclear.We show that heat stress results in heterochromatin disruption coupled with histone hyperacetylation and DNA hypomethylation. Two plant‐specific histone deacetylases HD2B and HD2C could promote DNA methylation and relieve the heat‐induced heterochromatin decondensation. We noted that most DNA methylation regulated by HD2B and HD2C is lost upon heat stress. HD2B‐ and HD2C‐regulated histone acetylation and DNA methylation are dispensable for heterochromatin maintenance under normal conditions, but critical for heterochromatin stabilization under heat stress.We further showed that HD2B and HD2C promoted DNA methylation through associating with ARGONAUTE4 in nucleoli and Cajal bodies, and facilitating its nuclear accumulation. Thus, HD2B and HD2C act both canonically and noncanonically to stabilize heterochromatin under heat stress.This study not only reveals a novel plant‐specific crosstalk between histone deacetylases and key factor of DNA methylation pathway, but also uncovers their new roles in chromatic regulation of plant heat tolerance. [ABSTRACT FROM AUTHOR]

The probiotic Weizmannia coagulans (W. coagulans) BC2000 can increase the abundance of intestinal transforming ellagic acid (EA) bacteria and inhibit metabolic disorders caused by hyperlipidemia by activating liver autophagy. This study aimed to investigate the inhibitory effects of W. coagulans BC2000 and EA on hyperlipidemia-induced cholesterol metabolism disorders. C57BL/6J mice (n = 10 in each group) were fed a low-fat diet, high-fat diet (HFD), HFD supplemented with EA, HFD supplemented with EA and W. coagulans BC77, HFD supplemented with EA, and W. coagulans BC2000. EA and W. coagulans BC2000 supplementation prevented HFD-induced hypercholesterolemia and promoted fecal cholesterol excretion. Transcriptome analysis showed that primary bile acid biosynthesis in the liver was significantly activated by EA and W. coagulans BC2000 treatments. EA and W. coagulans BC2000 treatment also significantly increased the intestinal Eggerthellaceae abundance and the liver EA metabolites, iso-urolithin A, Urolithin A, and Urolithin B. Therefore, W. coagulans BC2000 supplementation promoted the intestinal transformation of EA, which led to the upregulation of liver bile synthesis, thus preventing hypercholesterolemia. [ABSTRACT FROM AUTHOR]

Levilactobacillus brevis strains can be isolated from traditional Chinese pickles and used as the starter cultures to improve the nutritional profiles of fermented juices. Three L. brevis strains (LBG-29, LBG-24, LBD–14) that produce high levels of gamma-aminobutyric acid (GABA; >300 mg/L) were isolated from traditional Chinese pickles. The strains showed tolerance to low pH and high bile salts and exhibited safety in vitro. Litchi juice was fermented using each strain at 37 °C for 48 h. The litchi juice was determined to be a good substrate for fermentation as the process enhanced its functional profile. Overall, cell vitality increased (above 8.7 log10 CFU/mL), the antioxidant activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric ion-reducing antioxidant power (FRAP) were significantly increased, and the antioxidant capacity of the 2,2′-amino-di(3-ethyl-benzothiazoline sulphonic acid-6)ammonium salt (ABTS) was decreased. There was also a significant increase in the GABA and acetic acid content after LBG-29 and LBG-24 fermentation. It was thus determined that the LBG-29 and LBG-24 strains could be used to improve beverage functionality and aid in the development of new products. This is the first report of litchi fermentation using L. brevis as a starter culture. Further research is required to elucidate the functional benefits for the human body and the nutritional and functional properties during its shelf life. [ABSTRACT FROM AUTHOR]

(1) Background: Ellagic acid (EA) acts as a product of gut microbiota transformation to prevent insulin resistance, which is limited by high-fat diet (HFD)-induced dysbiosis. The aim of this study was to investigate the synergistic effects and mechanisms of supplementation with the probiotic Weizmannia coagulans (W. coagulans) on the prevention of insulin resistance by EA; (2) Methods: C57BL/6J mice were divided into five groups (n = 10/group): low-fat-diet group, high-fat-diet group, EA intervention group, EA + W. coagulans BC77 group, and EA + W. coagulans BC2000 group; (3) Result: W. coagulans BC2000 showed a synergistic effect on EA's lowering insulin resistance index and inhibiting high-fat diet-induced endotoxemia. The combined effect of BC2000 and EA activated the autophagy pathway in the mouse liver, a urolithin-like effect. This was associated with altered β-diversity of gut microbiota and increased Eggerthellaceae, a potential EA-converting family. Ellagic acid treatment alone and the combined use of ellagic acid and W. coagulans BC77 failed to activate the hepatic autophagy pathway; (4) Conclusions: W. coagulans BC2000 can assist EA in its role of preventing insulin resistance. This study provides a basis for the development of EA-rich functional food supplemented with W. coagulans BC2000. [ABSTRACT FROM AUTHOR]

Summary: RPA2A is a subunit of the conserved heterotrimeric replication protein A (RPA) in Arabidopsis, which is an essential replisome component that binds to single‐stranded DNA during DNA replication. RPA2A controls a set of developmental processes, but the underlying mechanism is largely unknown.Here we show that RPA2A represses key flowering genes including FLOWERING LOCUS T (FT), AGAMOUS (AG) and AGAMOUS LIKE 71 (AGL71) to suppress floral transition by cooperating with the PRC2 complex.RPA2A is vigorously expressed in dividing cells and required for correct DNA replication. Mutation of RPA2A leads to early flowering, which is dependent on ectopic expression of key flowering genes including FT molecularly and genetically. RPA2A and PRC2 have common target genes including FT, AG and AGL71 supported using genetic analysis, transcriptome profiling and H3K27me3 ChIP‐seq analysis. Furthermore, RPA2A physically interacts with PRC2 components CLF, EMF2 and MSI1, which recruits CLF to the chromatin loci of FT, AG and AGL71.Together, our results show that the replication protein RPA2A recruits PRC2 to key flowering genes through physical protein interaction, thereby repressing the expression of these genes to suppress floral transition in Arabidopsis. [ABSTRACT FROM AUTHOR]

Melanogenesis is a process to synthesize melanin, which is a primary responsibility for the pigmentation of human skin, eye and hair. In order to study the effect of polyoxometalates on tyrosinase activity and melanin content in mouse melanocytes, four polyoxometalates with Dawson structure were synthesized. Intracellular and docking studies have shown that the two transition metal phosphomolybdic acids (H8[P2Mo17Fe(OH2)61] and H8[P2Mo17Ni(OH2)61]) are highly effective melanogenesis inhibitors with 22.4 % and 24.1 % inhibitory activities at a concentration of 200 μM. Among the four POMs synthesized, the three phosphomolybdic acids showed extremely significant inhibitory effects on the tyrosinase activity in B16 cells (p<0.0001), and the inhibitory activities were 77.5 %, 79.3 % and 44.4 % at a concentration of 200 Μm, respectively. MTT reduction experiments show that the three polyacids (H6[P2Mo18O62], H8[P2Mo17Co(OH2)61] and H8[P2Mo17Ni(OH2)61]) have basically no effect on the viability of B16 cells. Molecular dynamics simulation studies also show that H8[P2Mo17Ni(OH2)61] forms a stable complex with tyrosinase, with a docking fraction of −51.54 kcal/mol. Based on intracellular and docking studies, we believe that H8[P2Mo17Ni(OH2)61] is a promising candidate for safe cosmetic development. [ABSTRACT FROM AUTHOR]

Protein engineering is an effective method to improve the thermal stability of biological macromolecules. Cytidine monophosphate kinase (CMK) is a key enzyme involved in nucleotide metabolism and participates in the production of cytidine triphosphate. It has previously been confirmed that CMK shows low thermal stability. This study aimed to enhance the thermal stability of CMK. Herein, we first analyzed native CMK using PoPMuSiC. Thereafter, we constructed single point mutants (Q30G, P62R, E85I, D148W and K165L) and multipoint mutants of CMK with higher thermal stability using site-directed mutagenesis. The thermal stability of the mutant Q30G/E85I/K165L was observed to be 1.2-fold higher than that of the wild type. The mutants were then allowed to catalyse 3′-sialyllactose (3′-SL) synthesis. After 51.72 mmol/L N-acetylneuraminic acid (sialic acid) was consumed in a 25 mL reaction system and 50.67 mmol/L 3′-SL was obtained, a decrease of 2 h was recorded in the reaction time, whereas the yield rate increased by 33.6%. The results suggest that the mutant Q30G/E85I/K165L can improve the thermal stability of CMK and its catalytic efficiency for 3′-SL synthesis. These findings are crucial for various applications involving enzyme conversion. [ABSTRACT FROM AUTHOR]

3-fucosyllactose (3-FL) and 2'-fucosyllactose (2'-FL), are two important fucosylated oligosaccharides in human milk. Extensive studies on 2'-FL enabled its official approval for use in infant formula. However, development of 3-FL has been somewhat sluggish due to its low content in human milk and poor yield in enlarged production. Here, an α-1,3-fucosyltransferase mutant was introduced into an engineered Escherichia coli (E. coli) capable of producing GDP-L-fucose, leading to a promising 3-FL titer in a 5.0-L bioreactor. To increase the availability of cofactors (NADPH and GTP) for optimized 3-FL production, zwf, pntAB , and gsk genes were successively overexpressed, finally resulting in a higher 3-FL level with a titer of 35.72 g/L and a yield of 0.82 mol 3-FL/mol lactose. Unexpectedly, the deletion of pfkA gene led to a much lower performance of 3-FL production than the control strain. Still, our strategy achieved the highest 3-FL level in E. coli to date. [ABSTRACT FROM AUTHOR]

2'-Fucosyllactose (2'-FL) is one of the most important oligosaccharides in human milk. In this study, a glucose–glycerol mixed carbon source and the deletion of the genes arcA and iclR were attempted for the first time in engineered Escherichia coli to improve 2'-FL production. The highest 2'-FL titre of 5.04 g/L, almost 1.4 times higher than that in the control strain, was obtained in the arcA mutant strain using shake-flask culture. In addition, the arcA mutant showed a significantly reduced accumulation of acetate. However, the deletion of iclR and the double deletion of arcA/iclR provided no benefit in terms of 2'-FL biosynthesis. Overall, these results suggest that deletion of arcA could efficiently increase the 2'-FL yield in E. coli and could lay a foundation for more efficient and larger-scale production. Moreover, in shake-flask culture under optimal conditions, the 2'-FL titer reached a maximum value of 7.14 g/L. [ABSTRACT FROM AUTHOR]

Lysine acetylation, one of the major types of post-translational modifications, plays critical roles in regulating gene expression and protein function. Histone deacetylases (HDACs) are responsible for removing acetyl groups from lysines of both histone and non-histone proteins. While tremendous progress has been made in understanding the function and mechanism of HDACs in animals in the past two decades, nearly half of the HDAC studies in plants were reported within the past five years. In this review, we summarize the major findings on plant HDACs, with a focus on the model plant Arabidopsis thaliana, and highlight the components, regulatory mechanisms, and biological functions of HDAC complexes. [ABSTRACT FROM AUTHOR]

Using a doubly-fed induction generator (DFIG), with an additional active or reactive damping controller, is a new method of suppressing the inter-area oscillation of a power system. However, using active power modulation (APM) may decrease the damping of the shaft oscillation mode of a DFIG and the system damping target cannot be achieved through reactive power modulation (RPM) in some cases. Either single APM or RPM does not consider system damping and torsional damping simultaneously. In this paper, an active-reactive coordinated dual-channel power modulation (DCPM) damping controller is proposed for DFIGs. First, considering the electromechanical parts and control structure of the wind turbine, an electromechanical transient model and an additional damping controller model of DFIGs are established. Then, the dynamic objective function for coordinating the parameters of the additional damping controller is proposed. The ratio between the active power channel and reactive power channel modulation is derived from the parameters optimized by the particle swarm optimization algorithm. Finally, the effectiveness and practicability of the designed strategy is verified by comparing it with a traditional, simple damping controller design strategy. Standard simulation system examples are used in the comparison. Results show that the DCPM is better at maximizing the damping control capability of the rotor-side controller of a DFIG and simultaneously minimizing adverse effects on torsional damping than the traditional strategy. [ABSTRACT FROM AUTHOR]

To reuse kitchen garbage for microbial oils, increase the liquid yield, and reduce the production cost, response surface methodology based on Box-Behnken design was employed to identify the optimum conditions for microbial oils production from kitchen garbage by the Geotrichum robustum G9 strain. Experimental results showed that the theoretical maximum lipid yield of 9.89 g/l was obtained with the following optimum conditions: time at 7.55 days, pH at 6.16, and temperature at 28 °C, when the lipid yield could reach 20 kg per ton of kitchen garbage. Analysis results on fatty acids composition and relative content by gas chromatography and mass spectrometry showed that the lipid in strain G9 cultured by kitchen garbage was mainly composed of 16-carbon and 18-carbon fatty acids. Such compositional features were similar to plant oil, the widely used feedstock for biodiesel at present. Kitchen garbage could be considered as ideal substrate for the G. robustum G9 strain for biodiesel production. The utilization of kitchen garbage for microbial oils production could reduce cost as well as reduce pollution. [ABSTRACT FROM AUTHOR]

Highlights: [•] Features of rice genome-wide DNA methylation and histone modification landscape. [•] Rice epigenetic regulators display specific developmental and stress–responsive functions. [•] Importance of epigenetic variation as a resource for trait variations and epiallele discovery in rice. [Copyright &y& Elsevier]

Abstract: Histone methylation plays an important role in epigenetic regulation of gene expression. Reversible methylation/demethylation of several histone lysine residues is mediated by distinct histone methyltransferases and histone demethylases. Jumonji proteins have been characterized to be involved in histone demethylation. Plant Jumonji homologues are found to have important functions in epigenetic processes, gene expression and plant development and to play an essential role in interplay between histone modifications and DNA methylation. This article is part of a Special Issue entitled: Epigenetic Control of cellular and developmental processes in plants. [Copyright &y& Elsevier]

Ideal Plant Architecture 1 (IPA1) encodes SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 14 (SPL14) with a pleiotropic effect on regulating rice development and biotic stress responses. To investigate the role of IPA1 in early seedling development, we developed a pair of IPA1/ipal-NILs and found that seed germination and early seedling growth were retarded in the ipa1-NIL. Analysis of the soluble sugar content, activity of amylase, and expression of the α-amylase genes revealed that the starch metabolism was weakened in the ipa1-NIL germinating seeds. Additionally, the content of bioactive gibberellin (GA) was significantly lower than that in the IPA1-NIL seeds at 48 h of imbibition. Meanwhile, the expression of GA synthesis-related gene OsGA20ox1 was downregulated, whereas the expression of GA inactivation-related genes was upregulated in ipa1-NIL seeds. In addition, the expression of OsWRKY51 and OsWRKY71 was significantly upregulated in ipa1-NIL seeds. Using transient dual-luciferase and yeast one-hybrid assays, IPA1 was found to directly activate the expression of OsWRKY51 and OsWRKY71, which would interfere with the binding affinity of GA-induced transcription factor OsGAMYB to inhibit the expression of α-amylase genes. In summary, our results suggest that IPA1 negatively regulates seed germination and early seedling growth by interfering with starch metabolism via the GA and WRKY pathways. [ABSTRACT FROM AUTHOR]

Sialyllactose (SL) is one of the most important acidic oligosaccharides in human milk, which plays an important role in the health of infants. In this work, an efficient multi-enzyme cascade was developed in a single whole cell to produce 3′-SL. We constructed two compatible plasmids with double cloning sites to co-express four genes. Different combinations were assessed to verify the optimal catalytic ability. Then, the conversion temperature, pH, and stability under the optimal temperature and pH were investigated. Moreover, the optimal conversion conditions and surfactant concentration were determined. By using the optimal conditions (35 °C, pH 7.0, 20 mM polyphosphate, 10 mM cytidine monophosphate (CMP), 20 mM MgCl2), 25 mL and 4 L conversion systems were carried out to produce 3′-SL. Similar results were obtained between different volume conversion reactions, which led the maximum production of 3′-SL to reach 53 mM from 54.2 mM of sialic acid (SA) in the 25 mL system and 52.8 mM of 3′-SL from 53.8 mM of SA in the 4 L system. These encouraging results demonstrate that the developed single whole-cell multi-enzyme system exhibits great potential and economic competitiveness for the manufacture of 3′-SL. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the stability and degradation kinetics of N-acetylneuraminic acid (Neu5Ac). The pH of the solution strongly influenced the stability of Neu5Ac, which was more stable at neutral pH and low temperatures. Here, we provide detailed information on the degradation kinetics of Neu5Ac at different pH values (1.0, 2.0, 11.0 and 12.0) and temperatures (60, 70, 80 and 90 °C). The study of the degradation of Neu5Ac under strongly acidic conditions (pH 1.0–2.0) is highly pertinent for the hydrolysis of polysialic acid. The degradation kinetics of alkaline deacetylation were also studied. Neu5Ac was highly stable at pH 3.0–10.0, even at high temperature, but the addition of H2O2 greatly reduced its stability at pH 5.0, 7.0 and 9.0. Although Neu5Ac has a number of applications in products of everyday life, there are no reports of rigorous shelf-life studies. This research provides kinetic data that can be used to predict product shelf lives at different temperatures and pH values. [ABSTRACT FROM AUTHOR]

Improved productivity of the two most commonly used cell lines in the biopharmaceutical industry, such as human embryonic kidney 293 (HEK293) and Chinese hamster ovary (CHO), could reduce production costs and increase manufacturing capacity. One method for increasing protein productivity is the addition of antioxidants during the cell culture process. In this study, we examined the effect of sialic acid (SA) on one HEK293 cell line and two CHO cell lines. The addition of SA to HEK293 cell led to a higher viable cell density (VCD), viability (Via), and a lower lactate content in the later stage of cultures. Further results showed that SA reduced the reactive oxygen species (ROS), improved cell viability, reduced lactate production, and increased antibody expression by more than 20% in the later stage of the two CHO cell lines cultures. Besides, an optimized dose of SA had no significant effect on acidic variants level aggregation level, N-linked glycosylation pattern, and SA content on antibodies. These results suggest that the addition of SA can improve the productivity of biopharmaceutical cell culture processes. [ABSTRACT FROM AUTHOR]

Among the human milk oligosaccharides (HMOs), one of the most abundant oligosaccharides and has great benefits for human health is 3′-sialyllactose (3′-SL). Given its important physiological functions and the lack of cost-effective production processes, we constructed an in vitro multi-enzymatic cofactor recycling system for the biosynthesis of 3′-SL from a low-cost substrate. First, we constructed the biosynthetic pathway and increased the solubility of cytidine monophosphate kinase (CMK) with chaperones. We subsequently identified that β-galactosidase (lacZ) affects the yield of 3′-SL, and hence with the lacZ gene knocked out, a 3.3-fold increase in the production of 3′-SL was observed. Further, temperature, pH, polyphosphate concentration, and concentration of divalent metal ions for 3′-SL production were optimized. Finally, an efficient biotransformation system was established under the optimized conditions. The maximum production of 3′-SL reached 38.7 mM, and a molar yield of 97.1% from N-acetylneuraminic acid (NeuAc, sialic acid, SA) was obtained. The results demonstrate that the multi-enzymatic cascade biosynthetic pathway with cofactor regeneration holds promise as an industrial strategy for producing 3′-SL. [ABSTRACT FROM AUTHOR]

DNA methylation loss can produce inheritable active epialleles in plants. The mechanism involved in the stable transmission of hypomethylated epimuations is presently not clear. Here we show that maintenance of a stably hypomethylated active epiallele in rice required a CHD3 protein (CHR729) and that over-expression of an H3K4me3 demethylase (JMJ703) or H3K27me3 methyltransferase (SDG711) could stably resilence the epiallele. CHR729 and JMJ703 have antagonistic function in H3K4me3 in maintaining the active state of the epiallele, whereas SDG711-mediated H3K27me3 was sufficient to stably repress the locus. The data suggest that H3K4me3 and H3K27me3 controlled by these chromatin regulators may be involved in stable transmission/resetting of epigenetic variation in rice. [ABSTRACT FROM AUTHOR]

• We revealed novel characteristics of histone marks related to transcription regulation by analyzing their genome-wide distributions. • We identified the histone marks that showed exonic enrichment, implying their involvement in co-transcriptional splicing. • We found that constitutively expressed genes (CEGs) and tissue-specific expressed genes (TSEGs) have unique respective features of histone mark distribution. Histone marks including histone modifications and histone variants may affect the processes of gene transcription and co-transcriptional RNA processing depending on their specific deposition patterns within genes. Here, we analyzed distribution patterns of rice histone marks and divided them into seven clusters according to their enrichment in promoter, transcription start site (TSS), and gene body regions. Expression levels of the genes in each cluster were explored to disclose the importance of histone marks in the processes of transcription. We show that: a) H3K4me3 and histone acetylation marks show locally different distributions at TSS, implying that they may play different roles in transcription initiation. b) H3K36me1 enriched at TSS has a negative effect on transcription. c) Genes with high level of expression were marked by H3K36me3 at both the TSS and body regions. In addition, we found that H3K4me2, H3K23ac, H3K4ac, and H2A.Z show exon-biased enrichment, suggesting they may be chromatin marks involved in co-transcriptional splicing. Finally, we identified histone marks that discriminate constitutive expression genes (CEGs) from tissue-specific expressed genes (TSEGs). Taken together, the analysis revealed distribution patterns of different histone marks in rice to infer their potential roles in transcription and RNA processing. The results lay foundation for further understanding the mechanism by which histone marks are involved in the regulation of these processes in plants. [ABSTRACT FROM AUTHOR]