Influence of Spider Silk Protein Structure on Mechanical and Biological Properties for Energetic Material Detection.

Spider silk protein, renowned for its excellent mechanical properties, biodegradability, chemical stability, and low immune and inflammatory response activation, consists of a core domain with a repeat sequence and non-repeating sequences at the N-terminal and C-terminal. In this review, we focus on the relationship between the silk structure and its mechanical properties, exploring the potential applications of spider silk materials in the detection of energetic materials.

Application of QSAR models for acute toxicity of tetrazole compounds administrated orally and intraperitoneally in rat and mouse.

Tetrazoles and their derivatives possess various biological activities, such as antibacterial, anti-fungal, and other activities. However, these compounds may induce specific cumulative and toxic effects in living organisms. Therefore, quantitative structure-activity relationship (QSAR) models were constructed to study the acute oral toxicity of tetrazoles in rats and mice. The toxicity data of 111 tetrazole compounds were collected using the ChemIDplus, ChEMBL and ECHA databases as response variables, while the PaDEL-descriptor generated the 2D descriptors as independent variables. The models were developed and validated following the OECD guidelines by the DTC-QSAR tool. Three QSAR models were successfully established for the oral routes of rat and mouse and the intraperitoneal route of mouse, respectively. The scatter plots showed high consistency between the training and test data sets. All the models successfully met the external and internal validation criteria. Most of the descriptors kept in the final models exhibited positive correlations with toxicity, whereas only 6 descriptors exhibited negative associations. Several chemicals were identified as response or structural outliers, based on the standardized residuals and leverage values. In conclusion, the findings of this investigation demonstrate that the proposed QSAR models hold promise in forecasting the acute toxicity of recently developed or synthesized tetrazole compounds, thereby mitigating potential risks to human health and the environment.

Strong Thermo-tolerant Silicone-Modified Waterborne Polyurethane/Polyimide Pressure-Sensitive Adhesive.

A waterborne polyurethane pressure-sensitive adhesive (WPUPSA) has the advantages of low pollution and good viscoelasticity. However, its poor thermo-tolerance limits its application in the field of high temperatures. Hence, a novel silicone-modified strong thermo-tolerant waterborne polyurethane/polyimide pressure-sensitive adhesive is developed as a way to remedy this problem. The single-chain structure of waterborne polyurethane (WPU) is transformed into a network structure by introducing the three-position network structure to increase the cohesive energy and heat resistance of the WPUPSA. Meanwhile, the primary chain of waterborne polyurethane (WPU) is modified by the reaction between pyromellitic dianhydride (PMDA) and isophorone diisocyanate (IPDI) to include an imide ring and a benzene ring with more stable structures and heat resistance. Characterization results of the prepared WPUPSA show that the thermo-tolerance index of the WPUPSA increases by 15.2% and the room temperature 180° peel strength and shear resistance of the WPUPSA increase by 80.9 and 231.8%, respectively. Meanwhile, the temperature corresponding to the maximum thermal decomposition rate of the samples is improved. More importantly, at 80 and 100 °C, the 180° peel strength and shear resistance of the modified samples are stronger than those of the unmodified samples. In addition, the energy storage modulus of WPUPSAs is also greater than the loss and increases with the increase of the frequency. Viscoelasticity dominates in the samples. This will provide new insight for the development of WPUPSAs in the field of high-temperature resistance.

Salidroside protect Chinese hamster V79 cells from genotoxicity and oxidative stress induced by CL-20.

Hexanitrohexaazaisowurtzitane (CL-20) is a high-energy elemental explosive widely used in chemical and military fields. CL-20 harms environmental fate, biosafety, and occupational health. However, there is little known about the genotoxicity of CL-20, in particular its molecular mechanisms. Therefore, this study was framed to investigate the genotoxic mechanisms of CL-20 in V79 cells and evaluate whether the genotoxicity could be diminished by pretreating the cells with salidroside. The results showed that CL-20-induced genotoxicity in V79 cells primarily through oxidative damage to DNA and mitochondrial DNA (mtDNA) mutation. Salidroside could significantly reduce the inhibitory effect of CL-20 on the growth of V79 cells and reduce the levels of reactive oxygen species (ROS), 8-hydroxy-2 deoxyguanosine (8-OHdG), and malondialdehyde (MDA). Salidroside also restored CL-20-induced superoxide dismutase (SOD) and glutathione (GSH) in V79 cells. As a result, salidroside attenuated the DNA damage and mutations induced by CL-20. In conclusion, oxidative stress may be involved in CL-20-induced genotoxicity in V79 cells. Salidroside could protect V79 cells from oxidative damage induced by CL-20, mechanism of which may be related to scavenging intracellular ROS and increasing the expression of proteins that can promote the activity of intracellular antioxidant enzymes. The present study for the mechanisms and protection of CL-20-mediated genotoxicity will help further to understand the toxic effects of CL-20 and provide information on the therapeutic effect of salidroside in CL-20-induced genotoxicity.

Toxicity prediction of 1,2,4-triazoles compounds by QSTR and interspecies QSTTR models.

1,2,4-triazole derivatives exhibit various biological activities, including antibacterial and antifungal properties. On the other hand, these chemicals may have unique cumulative and harmful effects on living organisms. The goal of this work is to use quantitative structure-toxicity relationship (QSTR) and interspecies quantitative toxicity-toxicity relationship (iQSTTR) models to predict the acute toxicity of 1,2,4-triazole derivatives. The QSTR models were generated by multiple linear regression (MLR) following the OECD recommendations for QSAR model development and validation. The iQSTTR models were constructed using data on acute oral toxicity in rats and mice, as well as the 2D descriptor. The application domain (AD) analysis was used to identify model outliers and determine if the forecast was credible. Six QSTR models were successfully constructed in rats and mice using various delivery methods, and the scatter plots demonstrated excellent consistency across training and test sets. According to external and internal validation criteria, all six QSTR models may be broadly accepted; however, the orally administered mice model was the optimum one among the six species. Several chemicals with leverage values above the requirements were identified as response or structural outliers in the training sets for six QSTR and two iQSTTR models. All outliers, however, fell slightly outside the threshold or had low prediction errors, which may have had little impact on the capacity to forecast and were therefore preserved in the final models. In fact, neither the QSTR nor the iQSTTR test sets contained any response outliers. Additionally, all external and internal validation results for the iQSTTR models were approved, with the iQSTTR models outperforming the comparable QSTR models, which are deemed more dependable. The QSTR and iQSTTR models performed well in predicting toxicity using test sets, which would be beneficial in evaluating and synthesizing newly discovered 1,2,4-triazoles derivatives with low toxicity and environmental hazard.

Cytotoxicity and inflammatory effects in human bronchial epithelial cells induced by polycyclic aromatic hydrocarbons mixture.

Polycyclic aromatic hydrocarbons (PAHs) are the most common contaminants in the air pollutants. Inhalation exposure to PAHs could increase the risk of respiratory disease, cardiovascular disease and even cancer. However, the biotoxicity of multi-component PAHs from atmospheric pollutants has been poorly studies. The main topic of this study was to investigate the PAHs mixture, which derived from atmospheric pollutants, induced toxic effects and inflammatory effects on human bronchial epithelial cells in vitro. The results showed that PAHs mixture could decrease the cell viability, increase the apoptosis rate, and induce cell cycle arrest at S-phase. Furthermore, the expression of inflammatory factors IL-1ß and IL-6 were increased and NF-κB signaling pathway was activated in PAHs mixture-treated cells. The findings of this study indicate that PAHs mixture-induced cytotoxicity and inflammation may be related to intracellular ROS generation and to the activated NF-κB signaling pathway.

NF-κB and FosB mediate inflammation and oxidative stress in the blast lung injury of rats exposed to shock waves.

Blast lung injury (BLI) is the major cause of death in explosion-derived shock waves; however, the mechanisms of BLI are not well understood. To identify the time-dependent manner of BLI, a model of lung injury of rats induced by shock waves was established by a fuel air explosive. The model was evaluated by hematoxylin and eosin staining and pathological score. The inflammation and oxidative stress of lung injury were also investigated. The pathological scores of rats' lung injury at 2 h, 24 h, 3 days, and 7 days post-blast were 9.75±2.96, 13.00±1.85, 8.50±1.51, and 4.00±1.41, respectively, which were significantly increased compared with those in the control group (1.13±0.64; P<0.05). The respiratory frequency and pause were increased significantly, while minute expiratory volume, inspiratory time, and inspiratory peak flow rate were decreased in a time-dependent manner at 2 and 24 h post-blast compared with those in the control group. In addition, the expressions of inflammatory factors such as interleukin (IL)-6, IL-8, FosB, and NF-κB were increased significantly at 2 h and peaked at 24 h, which gradually decreased after 3 days and returned to normal in 2 weeks. The levels of total antioxidant capacity, total superoxide dismutase, and glutathione peroxidase were significantly decreased 24 h after the shock wave blast. Conversely, the malondialdehyde level reached the peak at 24 h. These results indicated that inflammatory and oxidative stress induced by shock waves changed significantly in a time-dependent manner, which may be the important factors and novel therapeutic targets for the treatment of BLI.

Isolation and identification of a novel bacterium, Pseudomonas sp. ZyL-01, involved in the biodegradation of CL-20.

Hexanitrohexaazaisowurtzitane (CL-20) is a compound with a polycyclic cage and an N-nitro group that has been shown to play an unfavorable role in environmental fate, biosafety, and physical health. The aim of this study was to isolate the microbial community and to identify a single microbial strain that can degrade CL-20 with desirable efficiency. Metagenomic sequencing methods were performed to investigate the dynamic changes in the composition of the community diversity. The most varied genus among the microbial community was Pseudomonas, which increased from 1.46% to 44.63% during the period of incubation (MC0-MC4). Furthermore, the new strain was isolated and identified from the activated sludge by bacterial morphological and 16s rRNA sequencing analyses. The CL-20 concentrations decreased by 75.21 µg/mL and 74.02 µg/mL in 48 h by MC4 and Pseudomonas sp. ZyL-01, respectively. Moreover, ZyL-01 could decompose 98% CL-20 of the real effluent in 14 day's incubation with the glucose as carbon source. Finally, a draft genome sequence was obtained to predict possible degrading enzymes involved in the biodegradation of CL-20. Specifically, 330 genes that are involved in energy production and conversion were annotated by Gene Ontology functional enrichment analysis, and some of these candidates may encode enzymes that are responsible for CL-20 degradation. In summary, our studies indicate that microbes might be a valuable biological resource for the treatment of environmental contamination caused by CL-20 and that Pseudomonas sp. ZyL-01 might be a promising candidate for eradicating CL-20 to achieve a more biosafe environment and improve public health.

Global gene expression profiling of blast lung injury of goats exposed to shock wave.

PURPOSE: Blast lung injury (BLI) is the most common damage resulted from explosion-derived shock wave in military, terrorism and industrial accidents. However, the molecular mechanisms underlying BLI induced by shock wave are still unclear. METHODS: In this study, a goat BLI model was established by a fuel air explosive power. The key genes involved in were identified. The goats of the experimental group were fixed on the edge of the explosion cloud, while the goats of the control group were 3 km far away from the explosive environment. After successful modeling for 24 h, all the goats were sacrificed and the lung tissue was harvested for histopathological observation and RNA sequencing. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analysis were performed to identify the main enriched biological functions of differentially expressed genes (DEGs). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the consistency of gene expression. RESULTS: Of the sampled goat lungs, 895 genes were identified to be significantly differentially expressed, and they were involved in 52 significantly enriched GO categories. KEGG analysis revealed that DEGs were highly enriched in 26 pathways, such as cytokine-cytokine receptor interaction, antifolate resistance, arachidonic acid metabolism, amoebiasis and bile secretion, JAK-STAT, and IL-17 signaling pathway. Furthermore, 15 key DEGs involved in the biological processes of BLI were confirmed by qRT-PCR, and the results were consistent with RNA sequencing. CONCLUSION: Gene expression profiling provide a better understanding of the molecular mechanisms of BLI, which will help to set strategy for treating lung injury and preventing secondary lung injury induced by shock wave.

Characterization of wheat endoplasmic reticulum oxidoreductin 1 and its application in Chinese steamed bread.

This study investigated characteristics of recombinant wheat Endoplasmic Reticulum Oxidoreductin 1 (wEro1) and its influence on Chinese steamed bread (CSB) qualities. The purified wEro1 monomer, which contained two conserved redox active motif sites, bound to flavin adenine dinucleotide (FAD) cofactor with a molecular weight of ∼47 kDa. wEro1 catalyzed the reduction of both bound and free FAD, and its reduction activity of free FAD reached 7.8 U/mg. Moreover, wEro1 catalyzed the oxidation of dithiothreitol and wheat protein disulfide isomerase (wPDI). Both glutathione and the reduced ribonuclease could work as electron donors for wEro1 in catalyzing the oxidation of wPDI. Additionally, wEro1 supplementation improved the CSB qualities with an increased specific volume of CSB and decreased crumb hardness, which was attributed to water-insoluble wheat proteins increasing and gluten network strengthening. The results give an understanding of the properties and function of wEro1 to facilitate its application especially in the flour-processing industry.

Genome-wide identification and characterization of genes encoding cyclohexylamine degradation in a novel cyclohexylamine-degrading bacterial strain of Pseudomonas plecoglossicida NyZ12.

The Gram-negative strain of Pseudomonas plecoglossicida NyZ12 isolated from soil has the ability to degrade cyclohexylamine (CHAM). The genes encoding CHAM degradation by gram-negative bacteria, however, have not been reported previously. In this study, ORFs predicted to encode CHAM degradation by NyZ12 were identified by bioinformatics analysis. Differential expression of the proposed ORFs was analyzed via RNA-seq and quantitative reverse transcription-PCR (qRT-PCR), using RNA extracted from NyZ12 cultured with or without CHAM addition. One CHAM-inducible ORF, RK21_02867 predicted to encode a cyclohexanone monooxygenase (ChnB) was disrupted, as were five ORFs, RK21_00425, RK21_02631, RK21_04207, RK21_04637 and RK21_05539, that had weak homology to the only known cyclohexylamine oxidase (CHAO encoded by chaA) found in Brevibacterium oxydans IH-35A. We also found that a tandem array of five ORFs (RK21_02866-02870) shared homology with those in an operon responsible for oxidation of cyclohexanone to adipic acid, although the ORFs in strain NyZ12 were arranged in a different order with previously found in cyclohexane, cyclohexanol or cyclohexanone degradation strains. The ORFs in this cluster were all up-regulated when CHAM was supplied as the sole carbon source. When one of these five genes, RK21_02867 encoding cyclohexanone (CHnone) monooxygenase, was knocked out, NyZ12 could not grow on CHAM, but it accumulated equimolar amounts of CHnone. Our results show that strain NyZ12 metabolized CHAM directly to CHnone which was then further metabolized to adipate. Despite clearly identifying genes encoding the steps for metabolism of CHAM metabolites, not every one of the putative chaAs was differentially expressed in the presence of CHAM and deletion of each one individually did not completely eliminate the capacity of NyZ12 to degrade CHAM, though it did reduce its growth in several instances. Our results suggest that there is genetic redundancy encoding the initial step in the oxidation of CHAM to CHnone in NyZ12 and that its CHAOs differ considerably from the ChaA, originally described in Brevibacterium oxydans IH-35A.

Recombinant Wheat Endoplasmic Reticulum Oxidoreductin 1 Improved Wheat Dough Properties and Bread Quality.

Recombinant wheat endoplasmic reticulum oxidoreductin 1 (wEro1) with considerable ability was expressed in Escherichia coli. The functional roles of wEro1 in flour processing quality were investigated by farinographic, rheological, texture profile analysis, electrophoresis, size exclusion chromatography, scanning electron microscopy, and Fourier transform infrared spectroscopy. wEro1 exhibited an obvious oxidation activity of sulfhydryl groups in small molecule and protein. Addition of wEro1 could strengthen the processing quality of dough, indicated by the improved mixing characteristics, viscoelastic properties, and bread qualities. These improvement effects of wEro1 could be attributed to the formation of macromolecular gluten polymers and massive gluten networks by disulfide cross-linking. Additionally, the increased ß-turn structure further demonstrated the enhancement of dough strength. Moreover, the amount of peroxide in dough was improved significantly from 2.36 to 2.82 µmol/g of flour with 0.15% wEro1 treatment. Therefore, the results suggested that wEro1 is a promising novel flour improver.

Enzymatic Synthesis of l-Ascorbyl Fatty Acid Esters Under Ultrasonic Irradiation and Comparison of Their Antioxidant Activity and Stability.

A series of novel l-ascorbyl fatty acid esters were synthesized by catalization of Novozym(®) 435 under ultrasonic irradiation and characterized by infrared spectroscopy, electrospray ionization mass spectra, and nuclear magnetic resonance. Their properties especially antioxidant activity and stability were investigated. The results showed that the reducing power, the scavenging activity of hydroxyl radical and 2,2-diphenyl-1-picrylhydrazyl radical were decreased with the increase of the number of carbon atoms in fatty acid. The hydroxyl radical scavenging activity and reducing power of l-ascorbyl saturated fatty acid esters were better than that of tert-butylhydroquinone. The induction period in lipid oxidation of l-ascorbyl saturated fatty acid esters and tert-butylhydroquinone were longer than that of l-ascorbyl unsaturated fatty acid esters and l-ascorbic acid both in soybean oil and lard. Besides, the l-ascorbyl fatty acid esters showed different stabilities in different conditions by comparing with l-ascorbic acid, and the l-ascorbyl saturated fatty acid esters were more stable than l-ascorbyl unsaturated fatty acid esters in ethanol solution.

Complete genome sequence of the cyclohexylamine-degrading Pseudomonas plecoglossicida NyZ12.

Pseudomonas plecoglossicida NyZ12 (CCTCC AB 2015057), a Gram-negative bacterium isolated from soil, has the ability to degrade cyclohexylamine. The complete genome sequence of this strain (6,233,254bp of chromosome length) is presented, with information about the genes of characteristic enzymes responsible for cyclohexylamine oxidation to cyclohexanone and the integrated gene cluster for the metabolic pathway of cyclohexanone oxidation to adipate.

Biodegradation of hexachlorobenzene by a constructed microbial consortium.

A consortium comprised of an engineered Escherichia coli DH5α and a natural pentachlorophenol (PCP) degrader, Sphingobium chlorophenolicum ATCC 39723, was assembled for degradation of hexachlorobenzene (HCB), a persistent organic pollutant. The engineered E. coli strain, harbouring a gene cassette (camA (+) camB (+) camC) that encodes the F87W/Y96F/L244A/V247L mutant of cytochrome P-450cam (CYP101), oxidised HCB to PCP. The resulting PCP was then further completely degraded by ATCC 39723. The results showed that almost 40 % of 4 µM HCB was degraded by the consortium at a rate of 0.033 nmol/mg (dry weight)/h over 24 h, accompanied by transient accumulation and immediate consumption of the intermediate PCP, detected by gas chromatography. In contrast, in the consortium comprised of Pseudomonas putida PaW340 harbouring camA (+) camB (+) camC and ATCC 39723, PCP accumulated in PaW340 cells but could not be further degraded, which may be due to a permeability barrier of Pseudomonas PaW340 for PCP transportation. The strategy of bacterial co-culture may provide an alternative approach for the bioremediation of HCB contamination.