A New Composite Material with Energy Storage, Electro/Photo-Thermal and Robust Super-Hydrophobic Properties for High-Efficiency Anti-Icing/De-Icing.

All weather, high-efficiency, energy-saving anti-icing/de-icing materials are of great importance for solving the problem of ice accumulation on outdoor equipment surfaces. In this study, a composite material with energy storage, active electro-/photo-thermal de-icing and passive super-hydrophobic anti-icing properties is proposed. Fluorinated epoxy resin and MWCNTs/PTFE particles are used to prepare the top multifunctional anti-icing/de-icing layer, which exhibited super-hydrophobicity with water contact angle greater than 155° and conductivity higher than 69 S m-1 . The super-hydrophobic durability of the top layer is verified through tape peeling and sandpaper abrasion tests. The surface can be heated by applying on voltage or light illumination, showing efficient electro-/photo-thermal and all-day anti-icing/de-icing performance. The oleogel material at the bottom layer is capable to absorb energy during heating process and release it during cooling process by phase transition, which greatly delayed the freezing time and saved energy. The icing test of single ice droplet, electro-/photo-thermal de-icing and defrosting tests also proved the high efficiency and energy saving of the anti-icing/de-icing strategy. This study provided a new way to manufacture multi-functional materials for practical anti-icing/de-icing applications.

Golgi fucosyltransferase 1 reveals its important role in α-1,4-fucose modification of N-glycan in CRISPR/Cas9 diatom Phaeodactylum tricornutum.

Phaeodactylum tricornutum (Pt) is a critical microbial cell factory to produce a wide spectrum of marketable products including recombinant biopharmaceutical N-glycoproteins. N-glycosylation modification of proteins is important for their activity, stability, and half-life, especially some special modifications, such as fucose-modification by fucosyltransferase (FucT). Three PtFucTs were annotated in the genome of P. tricornutum, PtFucT1 was located on the medial/trans-Golgi apparatus and PtFucT2-3 in the plastid stroma. Algal growth, biomass and photosynthesis efficiency were significantly inhibited in a knockout mutant of PtFucT1 (PtFucT1-KO). PtFucT1 played a role in non-core fucose modification of N-glycans. The knockout of PtFucT1 might affect the activity of PtGnTI in the complex and change the complex N-glycan to mannose type N-glycan. The study provided critical information for understanding the mechanism of protein N-glycosylation modification and using microalgae as an alternative ecofriendly cell factory to produce biopharmaceuticals.

Endoplasmic reticulum-quality control pathway and endoplasmic reticulum-associated degradation mechanism regulate the N-glycoproteins and N-glycan structures in the diatom Phaeodactylum tricornutum.

Tunicamycin inhibits the first step of protein N-glycosylation modification. However, the physiological, transcriptomic, and N-glycomic effects of tunicamycin on important marine diatom Phaeodactylum tricornutum are still unknown. In this study, comprehensive approaches were used to study the effects of tunicamycin stress. The results showed that cell growth and photosynthesis were significantly inhibited in P. tricornutum under the tunicamycin stress. The soluble protein content was significantly decreased, while the soluble sugar and neutral lipid were dramatically increased to orchestrate the balance of carbon and nitrogen metabolisms. The stress of 0.3 µg ml-1 tunicamycin resulted in the differential expression of ERQC and ERAD related genes. The upregulation of genes involved in ERQC pathway, the activation of anti-oxidases and the differential expression of genes related with ERAD mechanism might be important for maintaining homeostasis in cell. The identification of N-glycans, especially complex-type N-glycan structures enriched the N-glycan database of diatom P. tricornutum and provided important information for studying the function of N-glycosylation modification on proteins. As a whole, our study proposed working models of ERQC and ERAD will provide a solid foundation for further in-depth study of the related mechanism and the diatom expression system.

MYB gene family in the diatom Phaeodactylum tricornutum revealing their potential functions in the adaption to nitrogen deficiency and diurnal cycle.

The MYB transcription factor (TF) family is one of the largest and most important TF families, regulating the growth and response of microalgae to stress. However, the gene structure and characteristics of Phaeodactylum tricornutum MYB TFs, and their functions under nitrogen deficiency, have not been explored yet. To identify all P. tricornutum MYB (PtMYB) genes, the MYB gene family was analyzed at the genome-wide level in this study. A total ofm26 PtMYB genes were identified from the genome of P. tricornutum. These PtMYB genes were divided into 5 subfamilies: 5R-MYB, 4R-MYB, R2R3-MYB, R1R2R3-MYB, and MYB-related proteins. Phylogenetical motif and gene structure analyses of MYB genes indicated that the number and proportion of MYB TFs were species-specific, and MYB genes exhibited a lot of duplication events from microalgae to higher plants. Furthermore, the differentially expressed patterns of all 26 PtMYB TFs implied that PtMYB genes might have functional specificity under nitrogen deficiency. Homology analysis of MYB genes revealed that PtMYB3, PtMYB15, and PtMYB21 might play important roles in the regulation of the diurnal cycle and response to nitrogen stress in P. tricornutum. PtMYB3, PtMYB15, and PtMYB21 genes might be used as potential candidate genes for further studying the regulatory mechanisms of P. tricornutum under nitrogen deficiency. This work provides an important foundation for the future research of the potential functions of PtMYB genes and its diurnal regulatory mechanisms under nitrogen deficiency.

Identification of a MarR Subfamily That Regulates Arsenic Resistance Genes.

In this study, comprehensive analyses were performed to determine the function of an atypical MarR homolog in Achromobacter sp. strain As-55. Genomic analyses of Achromobacter sp. As-55 showed that this marR is located adjacent to an arsV gene. ArsV is a flavin-dependent monooxygenase that confers resistance to the antibiotic methylarsenite [MAs(III)], the organoarsenic compound roxarsone(III) [Rox(III)], and the inorganic antimonite [Sb(III)]. Similar marR genes are widely distributed in arsenic-resistant bacteria. Phylogenetic analyses showed that these MarRs are found in operons predicted to be involved in resistance to inorganic and organic arsenic species, so the subfamily was named MarRars. MarRars orthologs have three conserved cysteine residues, which are Cys36, Cys37, and Cys157 in Achromobacter sp. As-55, mutation of which compromises the response to MAs(III)/Sb(III). GFP-fluorescent biosensor assays show that AdMarRars (MarR protein of Achromobacter deleyi As-55) responds to trivalent As(III) and Sb(III) but not to pentavalent As(V) or Sb(V). The results of RT-qPCR assays show that arsV is expressed constitutively in a marR deletion mutant, indicating that marR represses transcription of arsV. Moreover, electrophoretic mobility shift assays (EMSAs) demonstrate that AdMarRars binds to the promoters of both marR and arsV in the absence of ligands and that DNA binding is relieved upon binding of As(III) and Sb(III). Our results demonstrate that AdMarRars is a novel As(III)/Sb(III)-responsive transcriptional repressor that controls expression of arsV, which confers resistance to MAs(III), Rox(III), and Sb(III). AdMarRars and its orthologs form a subfamily of MarR proteins that regulate genes conferring resistance to arsenic-containing antibiotics. IMPORTANCE In this study, a MarR family member, AdMarRars was shown to regulate the arsV gene, which confers resistance to arsenic-containing antibiotics. It is a founding member of a distinct subfamily that we refer to as MarRars, regulating genes conferring resistance to arsenic and antimony antibiotic compounds. AdMarRars was shown to be a repressor containing conserved cysteine residues that are required to bind As(III) and Sb(III), leading to a conformational change and subsequent derepression. Here we show that members of the MarR family are involved in regulating arsenic-containing compounds.

Laminarin, a Major Polysaccharide in Stramenopiles.

During the processes of primary and secondary endosymbiosis, different microalgae evolved to synthesis different storage polysaccharides. In stramenopiles, the main storage polysaccharides are ß-1,3-glucan, or laminarin, in vacuoles. Currently, laminarin is gaining considerable attention due to its application in the food, cosmetic and pharmaceuticals industries, and also its importance in global biogeochemical cycles (especially in the ocean carbon cycle). In this review, the structures, composition, contents, and bioactivity of laminarin were summarized in different algae. It was shown that the general features of laminarin are species-dependence. Furthermore, the proposed biosynthesis and catabolism pathways of laminarin, functions of key genes, and diel regulation of laminarin were also depicted and comprehensively discussed for the first time. However, the complete pathways, functions of genes, and diel regulatory mechanisms of laminarin require more biomolecular studies. This review provides more useful information and identifies the knowledge gap regarding the future studies of laminarin and its applications.

Effect of thermotolerant bacterial inoculation on the microbial community during sludge composting.

A thermophilic bacterium (Geobacillus stearothermophilus CHB1) was inoculated in a sludge compost, and the effects of the inoculation on the abundance and structure of the bacterial community in the sludge compost were investigated using quantitative PCR and Illumina MiSeq sequencing. The results showed that the high-temperature stage (>50 °C) of the CHB1 and CK (control without inoculum) piles started on days 5 and 8, respectively, and lasted for 7 and 2 days, respectively, indicating the extension of the thermophilic phase by CHB1 inoculation in the sludge compost. At the end of composting, the CHB1 piles showed a higher loss of total organic carbon, lower C/N ratio, and lower moisture content. The abundance of bacteria in the CHB1 piles was significantly higher in the heating and thermophilic phase of composting but were lower than those of the CK in the cooling phase. The richness and diversity of the bacterial community in the thermophilic phase increased after inoculation with CHB1. After inoculation of CHB1, there were higher relative abundances of Firmicutes, Thermopolyspora, Thermobacillus, Thermomonas, Thermomonospora, and Thermovum, which can grow in a high-temperature environment. Furthermore, redundancy analysis indicated that total organic carbon, total nitrogen, C/N ratio, pH, temperature, and moisture were the significant parameters that affected the bacterial community structure during sludge composting. Our findings suggested that inoculation with CHB1 would enhance the quality and efficiency of composting.

Fusion of a family 20 carbohydrate-binding module (CBM20) with cyclodextrin glycosyltransferase of Geobacillus sp. CHB1 improves catalytic efficiency.

Cyclodextrin glycosyltransferase (CGTase) is an important industrial enzyme for production of cyclodextrins (CDs) from starch by intramolecular transglycosylation. CGTase consists of five domains labeled A to E. For optimizing catalytic activity of CGTase, CGTase of Geobacillus sp. was fused with the family 20 carbohydrate-binding module (CBM) of the Bacillus circulans strain 251 CGTase. The CBMbc251 that has a low binding free energy with maltohexaose, was selected by in silico design. Then the fusion enzyme, CGTΔE-CBMbc251, was constructed by fusing the CBMbc251 to the C-terminal region of CGTΔE. The fusion enzyme displayed an even greater enhancement of total α-cyclization activity (40.2%) and γ-cyclization activity (181.58%). Optimal reaction pH range was wilder and the thermal stability was better under 50 and 60 °C. Compared to the wild-type CGTase, the fusion enzyme showed a remarkable decrease in Km and a slight alteration in Vmax. The enhancement of soluble starch catalytic efficiency might be due to the changes of substrate binding ability in the critical substrate binding sites between the CBM and starch granule.

[Improving soluble expression of Geobacillus sp. B1 CGTase by errorprone PCR].

Objective: This study was aimed to enhance the extracellular enzymes activities and soluble expression of CGTase from Geobacillus sp. B1 by directed evolution. Methods: A library of CGTase mutants was constructed by introducing random mutagenesis using error-prone PCR to screen mutant enzymes with improved extracellular enzyme activities and soluble expression. After induction, expression and purification, the mutant enzyme was characterized. Results: After screening, two optimum mutants ds-6 and ep-9 with extracellular alpha-cyclization activity are respectively 1.72 times and 2.18 times of the original enzyme. The sequence of ep-9 cgt gene showed that three nucleotides substitution, G2005A, A2037G and T2081G were observed, and two of them caused amino acid changes. According to the 3D structure of Geobacillus sp. B1 cyclodextrin glucosetransferase mimicked by SWISS-MODEL Repository, two amino acid mutations were in rotating angle between beta angle and the random coil. The wild-type CGTase or ep-9 genes was ligated with pET-28 (a)-OmpA vector, and expressed in E. coli BL21 (DE3). After induced by lactose, CGTases were purified and characterized. The results showed that the specific ß-cyclization activity of the evolved CGTase was 1.31-fold than that of the wild-type CGTase, and the Km decreased from 4.3 to 3.74 g/L. The pH stability of the evolved CGTase was better than wild-type CGTase. Site-directed mutagenesis demonstrated the key to improve the soluble expression level and extracellular enzyme activity was G2005A. Conclusion: Directed evolution by error-prone PCR of Geobacillus sp. B1 CGTase gene is effective to improve extracellular enzyme activities and soluble expression, in particular mutation occurred in the G2005A.

The characteristics of PtHSP40 gene family in Phaeodactylum tricornutum and its response to environmental stresses.

Diatom has evolved response mechanisms to cope with multiple environmental stresses. Heat shock protein 40 (HSP40) plays a key role in these response mechanisms. HSP40 gene family in higher plants has been well-studied. However, the HSP40 gene family has not been systematically investigated in marine diatom. In this study, the bioinformatic characteristics, phylogenetic relationship, conserved motifs, gene structure, chromosome distribution and the transcriptional response of PtHSP40 to different environmental stresses were analyzed in the diatom Phaeodactylum tricornutum, and quantitative real-time PCR was conducted. Totally, 55 putative PtHSP40 genes are distributed to 21 chromosomes. All PtHSP40 proteins can be divided into four groups based on their evolutionary relationship, and 54 of them contain a conserved HPD (histidine-proline-aspartic acid tripeptide) motif. Additionally, six, eleven, ten and four PtHSP40 genes were significantly upregulated under the treatments of nitrogen starvation, phosphorus deprivation, 2,2',4,4'-tetrabrominated biphenyl ether (BDE-47) and ocean acidification, respectively. More interestingly, the expression level of 9 PtHSP40 genes was obviously upregulated in response to nickel stress, suggesting the sensitive to metal stress. The different expression models of PtHSP40 genes to environmental stresses imply the specificity of PtHSP40 proteins under different stresses. This study provides a systematic understanding of the PtHSP40 gene family in P. tricornutum and a comprehensive cognition in its functions and response mechanisms to environmental stresses.

Metabolisms and multiple functions of laminaran in marine algae under global change: A critical review.

Laminaran is a major storage of carbohydrate in marine algae. Its high content and potential functions draw increasing attention. However, our understanding of its metabolisms and functions is still fragmented. After reviewing, marine algae exhibit a spectacular capacity of laminaran accumulation especially in the diatom Odontella aurita (65 % DW). Marine particulate organic carbon (POC) also has high contents of laminaran (42 ± 21 % DW). Laminaran shows a diel variation trend in marine algae, the content of which increases in the day but decreases at night. Laminaran also significantly accumulates in the stationary phase of algal growth. Furthermore, the metabolic pathway of laminaran and the remolding carbon mechanism in response to marine nitrogen limitation are proposed and comprehensively discussed. Laminaran production in marine phytoplankton is predicted to increase in future warmer and CO2-enriched oceans. Laminaran has diverse biological functions, including antioxidant, antimicrobial, anti-cancer, immunomodulatory, wound healing, and prebiotics. In addition, laminaran is also a major carbon storage compound in marine algae, suggesting its significant ecological function in marine carbon cycle. This study provides new insight into algal laminaran functions and its response mechanisms to environmental and climate changes.

Based on cross-scale fusion attention mechanism network for semantic segmentation for street scenes.

Semantic segmentation, which is a fundamental task in computer vision. Every pixel will have a specific semantic class assigned to it through semantic segmentation methods. Embedded systems and mobile devices are difficult to deploy high-accuracy segmentation algorithms. Despite the rapid development of semantic segmentation, the balance between speed and accuracy must be improved. As a solution to the above problems, we created a cross-scale fusion attention mechanism network called CFANet, which fuses feature maps from different scales. We first design a novel efficient residual module (ERM), which applies both dilation convolution and factorized convolution. Our CFANet is mainly constructed from ERM. Subsequently, we designed a new multi-branch channel attention mechanism (MCAM) to refine the feature maps at different levels. Experiment results show that CFANet achieved 70.6% mean intersection over union (mIoU) and 67.7% mIoU on Cityscapes and CamVid datasets, respectively, with inference speeds of 118 FPS and 105 FPS on NVIDIA RTX2080Ti GPU cards with 0.84M parameters.

Degradation of poly(butylene adipate-co-terephthalate) films by Thermobifida fusca FXJ-1 isolated from compost.

In recent years, Poly(butylene adipate-co-terephthalate) (PBAT) films were wildly used due to its biodegradable properties. However, there are few reports of strains that can high efficiently degrade PBAT. Thermobifida fusca FXJ-1, a thermophilic actinomycete, was screened and identified from compost. FXJ-1 can efficiently degrade PBAT at 55 °C in MSM medium. The degradation rates of the pure PBAT film (PF), PBAT film used for mulching on agricultural fields (PAF), and PBAT-PLA-ST film (PPSF) were 82.87 ± 1.01%, 87.83 ± 2.00% and 52.53 ± 0.54%, respectively, after nine days of incubation in MSM medium. Cracking areas were monitored uniformly distributed on the surfaces of three kinds of PBAT-based films after treatment with FXJ-1 using scanning electron microscopy. The LC-MS results showed that PBAT might be degraded into adipic acid, terephthalic acid, butylene adipate, butylene terephthalate and butylene adipate-co-terephthalate, and these products are involved in the cleavage of ester bonds. We also found that amylase produced by FXJ-1 played an important role in the degradation of PPSF. FXJ-1 also showed an efficient PBAT-based films degradation ability in simulating compost environment, which implied its potential application in PBAT and starch-based film degradation by industrial composting.

PtrA regulates prodigiosin synthesis and biological functions in Serratia marcescens FZSF02.

Serratia marcescens is a gram-negative bacterium that is able to produce many secondary metabolites, such as the prominent red pigment prodigiosin (PG). In this work, a ptrA-disrupted mutant strain with reduced PG production was selected from Tn5 transposon mutants. RT-qPCR results indicated that ptrA promoted elevated transcription of the pig gene cluster in S. marcescens FZSF02. Furthermore, we found that ptrA also controls several other important biological functions of S. marcescens, including swimming and swarming motilities, biofilm formation, hemolytic activity, and stress tolerance. In conclusion, this study demonstrates that ptrA is a PG synthesis-promoting factor in S. marcescens and provides a brief understanding of the regulatory mechanism of ptrA in S. marcescens cell motility and hemolytic activity.

Resolving the dynamics of chrysolaminarin regulation in a marine diatom: A physiological and transcriptomic study.

Diatom containing different active biological macromolecules are thought to be an excellent microbial cell factory. Phaeodactylum tricornutum, a model diatom, is a superb chassis organism accumulating chrysolaminarin with important bioactivities. However, the characteristic of chrysolaminarin accumulation and molecular mechanism of the fluctuated chrysolaminarin in diatom are still unknown. In this study, physiological data and transcriptomic analysis were carried out to clarify the mechanism involved in chrysolaminarin fluctuation. The results showed that chrysolaminarin content fluctuated, from 7.41 % dry weight (DW) to 40.01 % DW during one light/dark cycle, increase by day and decrease by night. The similar fluctuated characteristic was also observed in neutral lipid content. Genes related to the biosynthesis of chrysolaminarin and neutral lipid were up-regulated at the beginning of light-phase, explaining the accumulation of these biological macromolecules. Furthermore, genes involved in carbohydrate degradation, cell cycle, DNA replication and mitochondria-localized ß-oxidation were up-regulated at the end of light phase and at the beginning of dark phase hinting an energy transition of carbohydrate to cell division during the dark period. Totally, our findings provide important information for the regulatory mechanism in the diurnal fluctuation of chrysolaminarin. It would also be of great help for the mass production of economical chrysolaminarin in marine diatom.

Fracture-Promoted Ultraslippery Ice Detachment Interface for Long-Lasting Anti-icing.

Ice accumulation on surfaces significantly jeopardizes the operational security and economic effectiveness of equipment. As one of the efficient anti-icing strategies, fracture-induced ice detachment strategy can realize low ice adhesion strength and is feasible for large-area anti-icing, but its application in harsh environment is restrained by mechanical robustness deterioration due to ultralow elastic moduli. It is still a challenge for fracture-promoted interfaces to reach ultralow ice adhesion and maintain strong mechanical robustness. Drawing inspiration from subcutaneous tissue, we propose a multiscale interpenetrating reinforcing method to develop a fracture-promoted ultraslippery ice detachment interface. Our approach minimizes elastic deformation and the stress threshold of fracture initiation during ice detachment, ensuring fast and noninjurious ice detachment on the interface. At the same time, this method reinforces the mechanical robustness of the fracture-promoted ultraslippery interface, making it possible to ensure long-term operation under harsh conditions. The superiority is revealed by ultralow ice adhesion strength below 20 kPa at -30 °C even after 200 continuous abrasion cycles, as well as efficient ice shedding during dynamic anti-icing tests, which is clarified by theoretical prediction and experimental verification. This work is expected to enlighten the design of next-generation durable anti-icing interface.

Citrobacter portucalensis Sb-2 contains a metalloid resistance determinant transmitted by Citrobacter phage Chris1.

Bacterial adaptation to extreme environments is often mediated by horizontal gene transfer (HGT) via genetic mobile elements. Nevertheless, phage-mediated HGT conferring bacterial arsenic resistance determinants has rarely been investigated. In this study, a highly arsenite and antimonite resistant bacterium, Citrobacter portucalensis strain Sb-2, was isolated, and genome analysis showed that several putative arsenite and antimonite resistance determinants were flanked or embedded in prophages. Furthermore, an active bacteriophage carrying one of the ars clusters (arsRDABC arsR-yraQ/arsP) was obtained and sequenced. These genes encoding putative arsenic resistance determinants were induced by arsenic and antimony as demonstrated by RT-qPCR, and one gene arsP/yraQ of the ars cluster was shown to give resistance to MAs(III) and Rox(III), thereby showing function. Here, we were able to directly show that these phage-mediated arsenic and antimony resistances play a significant role in adapting to As- and Sb-contaminated environments. In addition, we demonstrate that this phage is responsible for conferring arsenic and antimony resistances to C. portucalensis strain Sb-2.

A comparison of silver staining protocols for detecting DNA in polyester-backed polyacrylamide gel.

Eight silver-staining protocols were applied to detect DNA in polyester-backed gels to select the optimal. Results showed important differences in staining quality and that four methods were well-suited for TGGE gels due to high sensitivity and low background, including the Bassam et al. methods, the manufacturer method and our improved method.

Transcriptional factor OmpR positively regulates prodigiosin biosynthesis in Serratia marcescens FZSF02 by binding with the promoter of the prodigiosin cluster.

Prodigiosin is a promising secondary metabolite mainly produced by Serratia marcescens. The production of prodigiosin by S. marcescens is regulated by different kinds of regulatory systems, including the EnvZ/OmpR system. In this study, we demonstrated that the regulatory factor OmpR positively regulated prodigiosin production in S. marcescens FZSF02 by directly binding to the promoter region of the prodigiosin biosynthesis cluster with a lacZ reporter assay and electrophoretic mobility shift assay (EMSA). The binding sequence with the pig promoter was identified by a DNase I footprinting assay. We further demonstrate that OmpR regulates its own expression by directly binding to the promoter region of envZ/ompR. For the first time, the regulatory mechanism of prodigiosin production by the transcriptional factor OmpR was revealed.

Immunoregulatory function of Dictyophora echinovolvata spore polysaccharides in immunocompromised mice induced by cyclophosphamide.

The purpose of this study was to investigate whether the Dictyophora echinovolvata spore polysaccharides (DESP) affect the immunity in immunocompromised mice induced by cyclophosphamide (CTX). The healthy female Kunming mice were randomly divided into six groups, including a normal control (NC) group, a positive control group, a model control (MC) group, and three groups treated with low-, intermediate-, and high-dose polysaccharide, respectively. A series of immunoregulatory properties were determined, including humoral and cellular immunity, immune function, and immune factors of mononuclear macrophages. Compared with NC and MC groups, treatment with DESP significantly increased the spleen index and decreased the thymus index; increased the serum concentrations of immunoglobulin (Ig)A, IgG, IgM, hemolysin, IL-1ß, and IL-2; delayed the allergic reaction; and improved the splenic lymphocyte transformation ability; and enhanced the phagocytosis of macrophages and the ability to secrete IL-6, TNF-α, caspase-1, and NO with DESP supplementation. These results indicated that DESP might have a good regulatory effect on CTX-induced immunodeficiency in mice, adjust the body's immune imbalance, and improve the symptoms of low immunity.