At least one in a dozen stars shows evidence of planetary ingestion.

Stellar chemical compositions can be altered by ingestion of planetary material1,2 and/or planet formation, which removes refractory material from the protostellar disk3,4. These 'planet signatures' appear as correlations between elemental abundance differences and the dust condensation temperature3,5,6. Detecting these planet signatures, however, is challenging owing to unknown occurrence rates, small amplitudes and heterogeneous star samples with large differences in stellar ages7,8. Therefore, stars born together (that is, co-natal) with identical compositions can facilitate the detection of planet signatures. Although previous spectroscopic studies have been limited to a small number of binary stars9-13, the Gaia satellite14 provides opportunities for detecting stellar chemical signatures of planets among co-moving pairs of stars confirmed to be co-natal15,16. Here we report high-precision chemical abundances for a homogeneous sample of ninety-one co-natal pairs of stars with a well defined selection function and identify at least seven instances of planetary ingestion, corresponding to an occurrence rate of eight per cent. An independent Bayesian indicator is deployed, which can effectively disentangle the planet signatures from other factors, such as random abundance variation and atomic diffusion17. Our study provides evidence of planet signatures and facilitates a deeper understanding of the star-planet-chemistry connection by providing observational constraints on the mechanisms of planet engulfment, formation and evolution.

Rosmarinic acid ameliorates autoimmune responses through suppression of intracellular nucleic acid-mediated type I interferon expression.

Recognition of intracellular nucleic acids is a vital step for host to mount prompt immune responses against microbial pathogens. However, inappropriate response to self-nucleic acids leads to sustained type I interferon (IFN) production, which is implicated in the development of several autoimmune diseases, such as Aicardi-Goutières syndrome (AGS). Therefore, effective confinement of intracellular nucleic acid-induced IFN expression is a potential strategy for the treatment of such autoimmune diseases. In this study, we found that rosmarinic acid (RA), a natural compound isolated from rosemary, inhibits intracellular nucleic acid-stimulated IFN expression. Mechanistic investigation revealed that RA binds to both G3BP1 and cGAS, and impairs cGAS activation through disrupting the binding of DNA with cGAS. More importantly, we showed that RA could effectively attenuate the expression of IFN-stimulated genes (ISGs) in the well-established cell models for AGS. Thus, our study provides a promising compound for the treatment of autoimmune responses induced by aberrant nucleic acid-sensing.

Inhibitory effect of (E)-2-heptenal on Aspergillus flavus growth revealed by metabolomics and biochemical analyses.

The prevention of fungal proliferation in postharvest grains is critical for maintaining grain quality and reducing mycotoxin contamination. Fumigation with natural gaseous fungicides is a promising and sustainable approach to protect grains from fungal spoilage. In this study, the antifungal activities of (E)-2-alkenals (C5-C10) on Aspergillus flavus were tested in the vapor phase, and (E)-2-heptenal showed the highest antifungal activity against A. flavus. (E)-2-Heptenal completely inhibited A. flavus growth at 0.0125 µL/mL and 0.2 µL/mL in the vapor phase and liquid contact, respectively. (E)-2-Heptenal can disrupt the plasma membrane integrity of A. flavus via leakage of intracellular electrolytes. Scanning electron microscopy indicated that the mycelial morphology of A. flavus was remarkably affected by (E)-2-heptenal. Metabolomic analyses indicated that 49 metabolites were significantly differentially expressed in A. flavus mycelia exposed to 0.2 µL/mL (E)-2-heptenal; these metabolites were mainly involved in galactose metabolism, starch and sucrose metabolism, the phosphotransferase system, and ATP-binding cassette transporters. ATP production was reduced in (E)-2-heptenal-treated A. flavus, and Janus Green B staining showed reduced cytochrome c oxidase activity. (E)-2-Heptenal treatment induced oxidative stress in A. flavus mycelia with an accumulation of superoxide anions and hydrogen peroxide and increased activities of superoxide dismutase and catalase. Simulated storage experiments showed that fumigation with 400 µL/L of (E)-2-heptenal vapor could completely inhibit A. flavus growth in wheat grains with 20% moisture; this demonstrates its potential use in preventing grain spoilage. This study provides valuable insights into understanding the antifungal effects of (E)-2-heptenal on A. flavus. KEY POINTS : • (E)-2-Heptenal vapor showed the highest antifungal activity against A. flavus among (C5-C10) (E)-2-alkenals. • The antifungal effects of (E)-2-heptenal against A. flavus were determined. • The antifungal actions of (E)-2-heptenal on A. flavus were revealed by metabolomics and biochemical analyses.

Transcriptomic and biochemical analyses revealed antifungal mechanism of trans-anethole on Aspergillus flavus growth.

Plant volatile compounds have great potential for preventing and controlling fungal spoilage in post-harvest grains. Recently, we have reported the antifungal effects of trans-anethole, the main volatile constituent of the Illicium verum fruit, on Aspergillus flavus. In this study, the inhibitory mechanisms of trans-anethole against the growth of A. flavus mycelia were investigated using transcriptomic and biochemical analyses. Biochemical and transcriptomic changes in A. flavus mycelia were evaluated after exposure to 0.2 µL/mL trans-anethole. Scanning electron microscopy showed that trans-anethole treatment resulted in the surface wrinkling of A. flavus mycelia, and calcofluor white staining confirmed that trans-anethole treatment disrupted the mycelial cell wall structure. Annexin V-fluorescein isothiocyanate/propidium iodide double staining suggested that trans-anethole induced apoptosis in A. flavus mycelia. Reduced mitochondrial membrane potential and DNA damage were observed in trans-anethole-treated A. flavus mycelia using 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-imidacarbocyanine and 4',6-diamidino-2-phenylindole staining, respectively. 2',7'- Dichloro-dihydro-fluorescein diacetate staining and biochemical assays demonstrated that trans-anethole treatment cause the accumulation of reactive oxygen species in the A. flavus mycelia. Transcriptome results showed that 1673 genes were differentially expressed in A. flavus mycelia exposed to trans-anethole, which were mainly associated with multidrug transport, oxidative phosphorylation, citric acid cycle, ribosomes, and cyclic adenosine monophosphate signaling. We propose that trans-anethole can inhibit the growth of A. flavus mycelia by disrupting the cell wall structure, blocking the multidrug transport process, disturbing the citric acid cycle, and inducing apoptosis. This study provides new insights into the inhibitory mechanism of trans-anethole on A. flavus mycelia and will be helpful for the development of natural fungicides. KEY POINTS: • Biochemical analyses of A. flavus mycelia exposed to trans-anethole were performed • Transcriptomic changes in trans-anethole-treated A. flavus mycelia were analyzed • An inhibitory mechanism of trans-anethole on the growth of A. flavus mycelia was proposed.

Protection of postharvest grains from fungal spoilage by biogenic volatiles.

Fungal spoilage of postharvest grains poses serious problems with respect to food safety, human health, and the economic value of grains. The protection of cereal grains from deleterious fungi is a critical aim in postharvest grain management. Considering the bulk volume of grain piles in warehouses or bins and food safety, fumigation with natural gaseous fungicides is a promising strategy to control fungal contamination on postharvest grains. Increasing research has focused on the antifungal properties of biogenic volatiles. This review summarizes the literature related to the effects of biogenic volatiles from microbes and plants on spoilage fungi on postharvest grains and highlights the underlying antifungal mechanisms. Key areas for additional research on fumigation with biogenic volatiles in postharvest grains are noted. The research described in this review supports the protective effects of biogenic volatiles against grain spoilage by fungi, providing a basis for their expanded application in the management of postharvest grains.

Surfactin inhibits Fusarium graminearum by accumulating intracellular ROS and inducing apoptosis mechanisms.

Fusarium graminearum, a devastating fungal pathogen, is the main pathogen of Fusarium head blight (FHB) in wheat globally; it results in significant yield loss and mycotoxin contamination that severely threatens global wheat production and food safety. However, despite ongoing efforts, controlling this pathogen still remains a major challenge. Surfactin, primarily synthesized by Bacillus sp. via non-ribosomal peptide synthetases, exhibits potent surfactant and antibacterial properties, but its antifungal mechanism has yet to be fully elucidated. We found that the EC50 of surfactin against hyphal growth of F. graminearum was 102.1 µg/mL, and control efficacy against wheat FHB under field conditions achieved 86.38% in wheat cultivar Huaimai 40 and 81.60% in wheat cultivar Zhoumai 36, indicating that surfactin has potential antifungal activity against F. graminearum. Accumulated intracellular ROS, decreased mitochondrial membrane potential (MMP), activated metacaspase activity and condensed chromatin, were induced by surfactin in F. graminearum hyphae, suggesting that growth inhibition of fungus is mainly caused by apoptosis-like cell death. Furthermore, accumulated intracellular ROS was evidenced to act as a key mediator of surfactin-induced apoptosis. Broad-spectrum caspase inhibitor Z-VAD-FMK treatment indicated that surfactin induces caspase-independent apoptosis in F. graminearum. Collectively, this study provides evidence that surfactin induces a ROS-mediated mitochondrial apoptosis in F. graminearum hyphae, and may exert its antifungal activity against F. graminearum by activating apoptosis. This study demonstrates the potential of surfactin as an antifungal agent for FHB biocontrol, provides a new perspective on the antifungal mechanism of surfactin against filamentous fungi, and contributes to the application of surfactin-producing microbes in the biocontrol of plant diseases.

Genomic insight into the scale specialization of the biological control agent Novius pumilus (Weise, 1892).

BACKGROUND: Members of the genus Novius Mulsant, 1846 (= Rodolia Mulsant, 1850) (Coleoptera, Coccinellidae), play important roles in the biological control of cotton cushion scale pests, especially those belonging to Icerya. Since the best-known species, the vedalia beetle Novius cardinalis (Mulsant, 1850) was introduced into California from Australia, more than a century of successful use in classical biological control, some species of Novius have begun to exhibit some field adaptations to novel but related prey species. Despite their economic importance, relatively little is known about the underlying genetic adaptations associated with their feeding habits. Knowledge of the genome sequence of Novius is a major step towards further understanding its biology and potential applications in pest control. RESULTS: We report the first high-quality genome sequence for Novius pumilus (Weise, 1892), a representative specialist of Novius. Computational Analysis of gene Family Evolution (CAFE) analysis showed that several orthogroups encoding chemosensors, digestive, and immunity-related enzymes were significantly expanded (P < 0.05) in N. pumilus compared to the published genomes of other four ladybirds. Furthermore, some of these orthogroups were under significant positive selection pressure (P < 0.05). Notably, transcriptome profiling demonstrated that many genes among the significantly expanded and positively selected orthogroups, as well as genes related to detoxification were differentially expressed, when N. pumilus feeding on the nature prey Icerya compared with the no feeding set. We speculate that these genes are vital in the Icerya adaptation of Novius species. CONCLUSIONS: We report the first Novius genome thus far. In addition, we provide comprehensive transcriptomic resources for N. pumilus. The results from this study may be helpful for understanding the association of the evolution of genes related to chemosensing, digestion, detoxification and immunity with the prey adaptation of insect predators. This will provide a reference for future research and utilization of Novius in biological control programs. Moreover, understanding the possible molecular mechanisms of prey adaptation also inform mass rearing of N. pumilus and other Novius, which may benefit pest control.

Transcriptome analysis reveals the underlying mechanism of heptanal against Aspergillus flavus spore germination.

Methods of controlling Aspergillus flavus contamination in agro-products have attracted attention because of its impact on global food security. We previously reported that the natural cereal volatile heptanal could effectively inhibit A. flavus growth and showed great potential as a bio-preservative agent. In this study, the minimum inhibitory concentration and minimum fungicide concentration of heptanal could change the surface morphology of A. flavus spores, causing them to wrinkle and collapse. Transcriptomic analysis showed that heptanal treatment significantly changed the expression of several genes involved in cell wall and plasma damage, reactive oxygen species (ROS) accumulation, energy metabolism, AMPK-activated protein kinase, biosynthesis of unsaturated fatty acids, RNA degradation, and DNA replication. Heptanal-induced early apoptosis of A. flavus spores was characterized by decreased mitochondrial membrane potential, increased intracellular ROS production, and DNA fragmentation. This study provides new insight into the inhibitory mechanism of heptanal against A. flavus and points to its potential application as a bio-preservative. KEY POINTS: • Heptanal can effectively inhibit A. flavus growth in cereal grains. • The transcriptional changes in A. flavus spores exposed to heptanal were analyzed. • The antifungal mechanism of heptanal against A. flavus was elucidated.

Transcriptomics analyses and biochemical characterization of Aspergillus flavus spores exposed to 1-nonanol.

The exploitation of plant volatile organic compounds as biofumigants to control postharvest decaying of agro-products has received considerable research attention. Our previous study reported that 1-nonanol, the main constituent of cereal volatiles, can inhibit Aspergillus flavus growth and has the potential as a biofumigant to control the fungal spoilage of cereal grains. However, the antifungal mechanism of 1-nonanol against A. flavus is still unclear at the molecular level. In this study, the minimum inhibitory concentration and minimum fungicidal concentration of 1-nonanol against A. flavus spores were 2 and 4 µL/mL, respectively. Scanning electron microscopy revealed that the 1-nonanol can distort the morphology of A. flavus spore. Annexin V-FITC/PI double staining showed that 1-nonanol induced phosphatidylserine eversion and increased membrane permeability of A. flavus spores. Transcriptional profile analysis showed that 1-nonanol treatment mainly affected the expression of genes related to membrane damage, oxidative phosphorylation, blockage of DNA replication, and autophagy in A. flavus spores. Flow cytometry analysis showed that 1-nonanol treatment caused hyperpolarization of mitochondrial membrane potential and accumulation of reactive oxygen species in A. flavus spores. 4',6-diamidino-2-phenylindole staining showed that treatment with 1-nonanol destroyed the DNA. Biochemical analysis results confirmed that 1-nonanol exerted destructive effects on A. flavus spores by decreasing intracellular adenosine triphosphate content, reducing mitochondrial ATPase activity, accumulating hydrogen peroxide and superoxide anions, and increasing catalase and superoxide dismutase enzyme activities. This study provides new insights into the antifungal mechanisms of 1-nonanol against A. flavus. KEY POINTS: • 1-Nonanol treatment resulted in abnormal morphology of A. flavus spores. • 1-Nonanol affects the expression of key growth-related genes of A. flavus. • The apoptosis of A. favus spores were induced after exposed to 1-nonanol.

Mechanisms underlying the inhibitory effects of linalool on Aspergillus flavus spore germination.

Biogenic volatile organic compounds hold remarkable potential for controlling fungal decay in agro- and food products. Recently, we reported that linalool, the major volatile component of the Zanthoxylum schinifolium pericarp, showed great potential as a biofumigant to control Aspergillus flavus growth in postharvest grains. In this study, the inhibitory effects of linalool on A. flavus growth in stored grains and its underlying mechanism were investigated through transcriptomic and biochemical analyses. Linalool vapor at 800 µL/L can effectively prevent A. flavus growth in 22% moisture wheat grains. Linalool at 2 µL/mL completely inhibited the germination of A. flavus spores, and 10 µL/mL caused spore death. Scanning electron microscopy revealed that linalool treatment caused wrinkling and spore breakage. Transcriptomics showed that 3806 genes were significantly differentially expressed in A. flavus spores exposed to 2 µL/mL linalool, predominantly showing enrichment regarding the ribosome, DNA replication, glutathione metabolism, peroxisome, and MAPK signaling pathways. Flow cytometry showed that linalool treatment caused hyperpolarization of mitochondrial membrane potential. 4,6-Diamidino-2-phenylindole staining indicated that linalool caused DNA fragmentation in A. flavus spores, and monodansylcadaverine staining confirmed that linalool induced autophagy in A. flavus spores. We thus propose that linalool can damage the plasma membrane, cause mitochondrial dysfunction and DNA damage, and induce autophagy in A. flavus spores. These findings considerably improve our understanding of the mechanisms underlying the inhibitory effects of linalool on A. flavus, which is crucial regarding the development of applications to prevent postharvest grain spoilage due to A. flavus infestations. KEY POINTS: • The inhibitory potency of linalool on A. flavus spore germination was determined. • Transcriptomic analyses were performed to identify differentially expressed genes of A. flavus exposed to linalool. • A functional mechanism underlying the inhibitory effects of linalool on A. flavus spore germination is proposed.

The antifungal mechanisms of plant volatile compound 1-octanol against Aspergillus flavus growth.

The exploitation of active ingredients from plant volatile organic compounds as natural gaseous fungicides shows remarkable potential for controlling fungal decay in postharvest agroproducts. Although 1-octanol is a common component of cereal volatiles, its antifungal potency against spoilage fungi in postharvest grains remains unclear. In this study, we studied the effectiveness of 1-octanol against Aspergillus flavus growth in postharvest grains and its mechanisms of action. 1-Octanol vapor and liquid contact dose-dependently inhibited A. flavus spore germination and mycelial growth at a low concentration. The simulated storage experiment demonstrated that 300 µL/L of 1-octanol vapor completely controlled A. flavus growth in wheat, corn, and paddy grains with 20% moisture content. 1-Octanol treatment irreversibly damaged the conidial and mycelial morphology of A. flavus and caused electrolyte leakage due to reduced plasma membrane integrity. It induced apoptosis along with morphological abnormalities, phosphatidylserine externalization, mitochondrial membrane potential depolarization, intracellular reactive oxygen species accumulation, and DNA fragmentation in A. flavus cells. Metabolomic analysis revealed that 1-octanol treatment disrupted the biosynthesis of unsaturated fatty acids, ATP-binding cassette transporters, amino acid metabolism, and glycerophospholipid metabolism. This study demonstrated the promising application potential of 1-octanol as a biofumigant for preventing fungal spoilage of postharvest cereal grains. KEY POINTS: • (1) 1-Octanol inhibits Aspergillus flavus growth in the vapor phase and liquid contact; • (2) 1-Octanol damages membrane integrity and induces apoptosis of A. flavus; • (3) Metabolomic changes in A. flavus mycelia were analyzed after 1-octanol treatment.

Multiomics Analysis of Endocytosis upon HBV Infection and Identification of SCAMP1 as a Novel Host Restriction Factor against HBV Replication.

Hepatitis B virus (HBV) infection remains a major global health problem and the primary cause of cirrhosis and hepatocellular carcinoma (HCC). HBV intrusion into host cells is prompted by virus-receptor interactions in clathrin-mediated endocytosis. Here, we report a comprehensive view of the cellular endocytosis-associated transcriptome, proteome and ubiquitylome upon HBV infection. In this study, we quantified 273 genes in the transcriptome and 190 endocytosis-associated proteins in the proteome by performing multi-omics analysis. We further identified 221 Lys sites in 77 endocytosis-associated ubiquitinated proteins. A weak negative correlation was observed among endocytosis-associated transcriptome, proteome and ubiquitylome. We found 33 common differentially expressed genes (DEGs), differentially expressed proteins (DEPs), and Kub-sites. Notably, we reported the HBV-induced ubiquitination change of secretory carrier membrane protein (SCAMP1) for the first time, differentially expressed across all three omics data sets. Overexpression of SCAMP1 efficiently inhibited HBV RNAs/pgRNA and secreted viral proteins, whereas knockdown of SCAMP1 significantly increased viral production. Mechanistically, the EnhI/XP, SP1, and SP2 promoters were inhibited by SCAMP1, which accounts for HBV X and S mRNA inhibition. Overall, our study unveils the previously unknown role of SCAMP1 in viral replication and HBV pathogenesis and provides cumulative and novel information for a better understanding of endocytosis in response to HBV infection.

Antifungal mechanism of 1-nonanol against Aspergillus flavus growth revealed by metabolomic analyses.

Chemical control of fungal spoilage of postharvest cereal grains is an important strategy for the management of grain storage. Here, the potential antifungal activity of 1-nonanol, a main component of cereal volatiles, against Aspergillus flavus was studied. The growth of A. flavus was completely inhibited by 0.11 and 0.20 µL/mL 1-nonanol at vapor and liquid contact phases, respectively. Metabolomic analysis identified 135 metabolites whose expression was significantly different between 1-nonanol-treated and untreated A. flavus. These metabolites were involved in the tricarboxylic acid cycle, amino acid biosynthesis, protein degradation and absorption, aminoacyl-tRNA biosynthesis, mineral absorption, and in interactions with ABC transporters. Biochemical validation confirmed the disruptive effect of 1-nonanol on A. flavus growth, as indicated by the leakage of intracellular electrolytes, decreased succinate dehydrogenase, mitochondrial dehydrogenase, and ATPase activity, and the accumulation of reactive oxygen species. We speculated that 1-nonanol could disrupt cell membrane integrity and mitochondrial function and might induce apoptosis of A. flavus mycelia. Simulated grain storage experiments showed that 1-nonanol vapor, at a concentration of 264 µL/L, completely inhibited A. flavus growth in wheat, corn, and paddy grain with an 18% moisture content. This study provides new insights into the antifungal mechanism of 1-nonanol against A. flavus, indicating that it has a promising potential as a bio-preservative to prevent fungal spoilage of postharvest grains. KEY POINTS: • 1-Nonanol showed higher antifungal activity against A. flavus. • The antifungal mechanisms of 1-nonanol against A. flavus were revealed. • 1-Nonanol could damage cell membrane integrity and mitochondrial function.

Hexanal induces early apoptosis of Aspergillus flavus conidia by disrupting mitochondrial function and expression of key genes.

Aspergillus flavus is a notorious saprophytic fungus that compromises the quantity and quality of postharvest grains and produces carcinogenic aflatoxins. The natural compound hexanal disrupts cell membrane synthesis and mitochondrial function and induces apoptosis in A. flavus; here, we investigated the molecular mechanisms underlying these effects. The minimum inhibition and fungicidal concentration (MIC and MFC) of hexanal against A. flavus spores were 3.2 and 9.6 µL/mL, respectively. Hexanal exposure resulted in abnormal spore morphology and early spore apoptosis. These changes were accompanied by increased reactive oxygen species production, reduced mitochondrial membrane potential, and DNA fragmentation. Transcriptomic analysis revealed that hexanal treatment greatly altered the metabolism of A. flavus spores, including membrane permeability, mitochondrial function, energy metabolism, DNA replication, oxidative stress, and autophagy. This study provides novel insights into the mechanism underlying the antifungal activity of hexanal, suggesting that hexanal can be used an anti-A. flavus agent for agricultural applications. KEY POINTS: • Hexanal exposure resulted in abnormal spore morphology. • The apoptotic characteristics of A. flavus were induced after hexanal treatment. • Hexanal could change the expression of key A. flavus growth-related genes.

Metabolomic analyses revealed multifaceted effects of hexanal on Aspergillus flavus growth.

Hexanal, a natural volatile organic compound, exerts antifungal activity against Aspergillus flavus; however, the mechanisms underlying these effects are unclear. In this study, we found that the growth of A. flavus mycelium was completely inhibited following exposure to 0.4 µL/mL hexanal (minimal inhibitory concentration). A detailed metabolomics survey was performed to identify changes in metabolite production by A. flavus cells after exposure to 1/2 the minimal inhibitory concentration of hexanal for 6 h, which revealed significant differences in 70 metabolites, including 20 upregulated and 50 downregulated metabolites. Among them, levels of L-malic acid, α-linolenic acid, phosphatidylcholine, D-ribose, riboflavin, D-mannitol, D-sorbitol, and deoxyinosine were significantly reduced. The metabolomics results suggest that the metabolites are mainly involved in the tricarboxylic acid cycle (TCA), ABC transport system, and membrane synthesis in A. flavus cells. Hexanal treatment reduced succinate dehydrogenase and mitochondrial dehydrogenase activity and stimulated superoxide anion and hydrogen peroxide accumulation in A. flavus mycelia. Increases in the electric conductivity and A260nm of the culture supernatant indicated cell membrane leakage. Therefore, hexanal appears to disrupt cell membrane synthesis, induce mitochondrial dysfunction, and increase oxidative stress in A. flavus mycelia. KEY POINTS: • Metabolite changes of A. flavus mycelia were identified after hexanal treatment. • Most differential metabolites were downregulated in hexanal-treated A. flavus. • An antifungal model of hexanal against A. flavus was proposed.

Genome Shuffling of Bacillus velezensis for Enhanced Surfactin Production and Variation Analysis.

Surfactin is a promising microbial lipopeptide with wide applications in food, environmental, agricultural, and pharmaceutical fields. However, its high cost caused by low productivity largely limits the commercial application. In this study, genome shuffling was employed to improve surfactin production in Bacillus velezensis strain LM3403 via recursive protoplast fusion. RT-qPCR analysis was employed to evaluate the transcriptional variance of surfactin synthase genes and surfactin efflux gene to insight into the variance underlying the recombinant strain. After three rounds of genome shuffling, a high-yield and genetic stable recombinant F34 was obtained, exhibiting dramatic improvement in surfactin production (from 229.60 ± 7.10 mg/L to 908.15 ± 5.65 mg/L) with high proportion of long carbon chain homologues. Scale-up fermentation confirmed that F34 had good growth performance and reached the yield of 917.05 ± 10.25 mg/L in a 30 L fermenter, which was 3.99-fold that of the initial strain. RT-qPCR analysis showed that the transcriptional levels of surfactin synthase genes srfAA and sfp, and surfactin efflux gene swrC in F34 were 8.12-fold, 9.27-fold, and 8.45-fold higher than those of LM3403, respectively. The upregulation of genes were consistent with the high surfactin yield in F34, indicating the increased capability of surfactin biosynthesis and transmember efflux in F34. To our knowledge, this is the first attempt to employ genome shuffling to breeding a B. velezensis strain to improve surfactin yield. The research helps us to understand the mechanisms underlying surfactin overproduction and provide references for further rational strain improvement.

Expression of a wheat ß-1,3-glucanase in Pichia pastoris and its inhibitory effect on fungi commonly associated with wheat kernel.

ß-1,3-glucanases, the plant PR-2 family of pathogenesis-related (PR) proteins, can be constitutively expressed and induced in wheat crop to enhance its anti-fungal pathogen defense. This study aimed to investigate the inhibitory effect of wheat ß-1,3-glucanase on fungi most commonly associated with wheat kernel. A ß-1,3-glucanase from wheat was successfully expressed in Pichia pastoris X-33 and its biochemical and antifungal properties were characterized herein. The molecular weight of recombinant ß-1,3-glucanase is approximately 33 kDa. ß-1,3-glucanase displays optimal activity at pH 6.5, remaining relatively high at pH 5.5-8.0. The optimal reaction temperature of ß-1,3-glucanase is 50 °C, retaining approximately 84.0% residual activity after heat-treated at 50 °C for 1 h. The steady-state kinetic parameters of ß-1,3-glucanase against laminarin was determined and the Km and Vmax were 1.32 ±â€¯0.20 mg/ml and 96.4 ±â€¯4.4 U mg-1 protein, respectively. The inhibitory effect of purified ß-1,3-glucanase against the seven fungi commonly associated with wheat kernel was assessed in vitro. ß-1,3-glucanase exerted differential inhibitory effects on hyphal growth of Fusarium graminearum, Alternaria sp., A. glaucus, A. flavus, A. niger, and Penicillium sp. Spore formation and mycelial morphology of Alternaria sp., A. flavus, and A. niger were significantly affected by ß-1,3-glucanase (1U). The present results would help elucidate the mechanism underlying the inhibition of wheat ß-1,3-glucanases on pathogens.

Measurement of Dynamic Responses from Large Structural Tests by Analyzing Non-Synchronized Videos.

Image analysis techniques have been employed to measure displacements, deformation, crack propagation, and structural health monitoring. With the rapid development and wide application of digital imaging technology, consumer digital cameras are commonly used for making such measurements because of their satisfactory imaging resolution, video recording capability, and relatively low cost. However, three-dimensional dynamic response monitoring and measurement on large-scale structures pose challenges of camera calibration and synchronization to image analysis. Without satisfactory camera position and orientation obtained from calibration and well-synchronized imaging, significant errors would occur in the dynamic responses during image analysis and stereo triangulation. This paper introduces two camera calibration approaches that are suitable for large-scale structural experiments, as well as a synchronization method to estimate the time difference between two cameras and further minimize the error of stereo triangulation. Two structural experiments are used to verify the calibration approaches and the synchronization method to acquire dynamic responses. The results demonstrate the performance and accuracy improvement by using the proposed methods.

Damage Indexing Method for Shear Critical Tubular Reinforced Concrete Structures based on Crack Image Analysis.

Image analysis techniques have been applied to measure the displacements, strain field, and crack distribution of structures in the laboratory environment, and present strong potential for use in structural health monitoring applications. Compared with accelerometers, image analysis is good at monitoring area-based responses, such as crack patterns at critical regions of reinforced concrete (RC) structures. While the quantitative relationship between cracks and structural damage depends on many factors, cracks need to be detected and quantified in an automatic manner for further investigation into structural health monitoring. This work proposes a damage-indexing method by integrating an image-based crack measurement method and a crack quantification method. The image-based crack measurement method identifies cracks locations, opening widths, and orientations. Fractal dimension analysis gives the flexural cracks and shear cracks an overall damage index ranging between 0 and 1. According to the orientations of the cracks analyzed by image analysis, the cracks can be classified as either shear or flexural, and the overall damage index can be separated into shear and flexural damage indices. These damage indices not only quantify the damage of an RC structure, but also the contents of shear and flexural failures. While the engineering significance of the damage indices is structure dependent, when the damage indexing method is used for structural health monitoring, the damage indices safety thresholds can further be defined based on the structure type under consideration. Finally, this paper demonstrates this method by using the results of two experiments on RC tubular containment vessel structures.

ABIN1 inhibits HDAC1 ubiquitination and protects it from both proteasome- and lysozyme-dependent degradation.

ABIN1, an important immune regulator, has been shown to be involved in various cellular functions, such as immunity, development, tissue homeostasis, and tumor progression. It inhibits TNF- and TLR-induced NF-κB signaling activation and the consequent gene expression. Despite its functional significance, the mechanism of ABIN1 in the regulation of various cellular functions remains unclear. In this study, we identified HDAC1, a key regulator of eukaryotic gene expression and many important cellular events, including cell proliferation, differentiation, cancer and immunity, as an interacting partner of ABIN1. The results showed that ABIN1 acted as a modulator to down-regulate HDAC1 ubiquitination via three different linkages, thereby stabilizing HDAC1 by inhibiting its lysosomal and proteasomal degradation. Interestingly, the inhibitory function of ABIN1 required direct binding with HDAC1. Moreover, the level of p53, which was a tumor suppressor and a well-studied substrate of HDAC1, was under the regulation of ABIN1 via the modulation of HDAC1 levels, suggesting that ABIN1 was physiologically significant in tumor progression. This study has revealed a new function of ABIN1 in mediating HDAC1 modification and stability.