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2, 6-diisopropylaniline (2, 6-DIPA) is a crucial non-intentionally organic additive that allows the assessment of the production processes, formulation qualities, and performance variations in biodegradable mulching film. Moreover, its release into the environment may have certain effects on human health. Hence, this study developed simultaneous heating hydrolysis–extraction and amine switchable hydrophilic solvent vortex-assisted homogeneous liquid–liquid microextraction for the gas chromatography–mass spectrometry analysis of the 2, 6-DIPA additive and its corresponding isocyanates in poly(butylene adipate-co-terephthalate) (PBAT) biodegradable agricultural mulching films. The heating hydrolysis–extraction conditions and factors influencing the efficiency of homogeneous liquid–liquid microextraction, such as the type and volume of amine, homogeneous-phase and phase separation transition pH, and extraction time were investigated and optimized. The optimum heating hydrolysis–extraction conditions were found to be a H2SO4 concentration of 2.5 M, heating temperature of 87.8 °C, and hydrolysis–extraction time of 3.0 h. As a switchable hydrophilic solvent, dipropylamine does not require a dispersant. Vortex assistance is helpful to speed up the extraction. Under the optimum experimental conditions, this method exhibits a better linearity (0.0144~7.200 μg mL−1 with R = 0.9986), low limit of detection and quantification (0.0033 μg g−1 and 0.0103 μg g−1), high extraction recovery (92.5~105.4%), desirable intra- and inter-day precision (relative standard deviation less than 4.1% and 4.7%), and high enrichment factor (90.9). Finally, this method was successfully applied to detect the content of the additive 2, 6-DIPA in PBAT biodegradable agricultural mulching films, thus facilitating production process monitoring or safety assessments. [ABSTRACT FROM AUTHOR]

The moisture content of cigar leaves during drying is an important indicator for controlling the management of drying rooms. At present, the determination of cigar leaf moisture content is mainly dependent on traditional destructive detection methods, which are inefficient and damaging to plants. In this study, a Convolution Neural Network method consisting of digital images for monitoring the moisture content of cigar leaves during the drying process was proposed. In this study, the Convolution Neural Network model was trained to learn the relationship between the images and the corresponding moisture content using the extracted colour, shape, and texture features as input factors. In order to compare the Convolution Neural Network estimation results, a widely used traditional machine learning algorithm was applied. The results demonstrated that the estimated value of Convolution Neural Network agreed with the predicted value; the R² was 0.9044, and the average accuracy was 87.34%. These results were better than those produced by traditional machine learning methods. The generalization test of the proposed method was conducted using varieties of cigar leaves in other drying rooms. The results showed that Convolution Neural Network is a viable method for an accurate estimation of the moisture content, the R² was 0.8673 and the average accuracy was 86.81%. The Convolution Neural Network established by the features extracted from digital images could accurately estimate the moisture content of cigar leaves during drying and was therefore shown to be an effective monitoring tool. [ABSTRACT FROM AUTHOR]

Tobacco mildew and tobacco-specific nitrosamines (TSNAs) affect the quality of tobacco products during fermentation. Microbes are thought to play key roles in the development of specific properties of fermented tobacco; however, little is known about the bacteria involved in the fermentation process. This study aims to identify key microbes related to mildew and TSNA formation. Tobacco was fermented at 25 °C, 35 °C, and 45 °C for 2, 4, and 6 weeks, with unfermented samples used as controls. Our preliminary exploration found that TSNAs content elevated with the increase of temperature and period, and mildew was easy to occur at low temperature with short period. Hence, samples were divided into three groups: the temperature gradient group (25 °C, 35 °C, and 45 °C for 6 weeks); the low-temperature group (control, 25 °C for 2, 4, and 6 weeks); and the high-temperature group (control, 45 °C for 2, 4, and 6 weeks). After collecting fermented tobacco leaves, 16S rRNA gene sequencing was used to explore the structure and dynamic changes of bacterial community during fermentation. Methylobacterium and Deinococcus were shared between the temperature gradient and high-temperature groups and showed a linear downward trend; these might play a role in the production of TSNAs. Massilia, Ruminiclostridium, and Cellulosilyticum species increased with prolonged fermentation time in the low-temperature group; this might be associated with tobacco mildew. In summary, the microbial diversity of fermented tobacco was explored under different conditions. These findings might provide data and material support to improve the quality of fermented tobacco products; however, further omics based studies are warranted to analysis the gene and protein expression patter in the identified bacteria. [ABSTRACT FROM AUTHOR]

Tobacco bacterial wilt has seriously affected tobacco production. Ethyl methanesulfonate (EMS) induced tobacco bacterial wilt resistant mutants are important for the control of tobacco bacterial wilt. High-throughput sequencing technology was used to study the rhizosphere bacterial community assemblages of bacterial wilt resistant mutant tobacco rhizosphere soil (namely KS), bacterial wilt susceptible tobacco rhizosphere soil (namely GS) and bulk soil (namely BS) in Xuancheng, Huanxi, Yibin and Luzhou. Alpha analysis showed that the bacterial community diversity and richness of KS and GS in the four regions were not significantly different. However, analysis of intergroup variation in the top 15 bacterial communities in terms of abundance showed that the bacterial communities of KS and GS were significantly different from BS, respectively. In addition, pH, alkali-hydrolysable nitrogen (AN) and soil organic carbon (SOC) were positively correlated with the bacterial community of KS and negatively correlated with GS in the other three regions except Huanxi. Network analysis showed that the three soils in the four regions did not show a consistent pattern of network complexity. PICRUSt functional prediction analysis showed that the COG functions were similar in all samples. All colonies were involved in RNA processing and modification, chromatin structure and dynamics, etc. In conclusion, our experiments showed that rhizosphere bacterial communities of tobacco in different regions have different compositional patterns, which are strongly related to soil factors. [ABSTRACT FROM AUTHOR]

Abstract Carbapenem-resistant Enterobacteriaceae strains as a new serious threat for the public health have been increasingly reported worldwide. In this study, one multi-resistant Escherichia coli strain Z SH6 which co-carried bla KPC-2 , bla NDM-5 and bla CTX-M , was isolated from human blood sample. By using plasmid conjugation experiments, ZSH6 was found to harbor three plasmids carrying the bla NDM-5 gene, the bla KPC-2 and bla CTX-M gene, respectively. Whole-genome sequencing of Z SH6 yielded 122 scaffolds of chromosomal DNA and three circular plasmids including pZSH6- bla KPC-2 (46,319 bp), pZSH6- bla NDM-5 (46,161bp) and pZSH6- bla CTX-M (184,723). The isolate was classified to Sequence Type 2 and to the O89: H10 serotype. The results of genome analyses revealed that Z SH6 carried three virulence factors (capU , gad and iss) and twenty resistance genes [ bla KPC-2 bla NDM-5 , bla CTX-M-3 , bla CTX-M-65 , bla TEM-1 , floR , tet(A) , tet(B) , dfrA17 , aadA5 , sul1 , mdf(A) , mph(A) , erm(B) , aph(3′)-Ia , aph(3′)-Ib , aph(4)-Ia , aph(6)-Id , aac(3)-Iva , aac(3)-IId ]. Therefore, the co-existence of such a large number of resistance genes in multiple plasmids making Z SH6 highly resistant to almost all kinds of commonly used antibiotics, and brings a serious challenge for resistance control and clinical treatment of infections caused by this bacterium. Highlights • O89: H10 E.coli Z SH6 strain co-carried a large number resistance genes. • E.coli Z SH6 strain co-carried three plasmids. • Three plasmids were pZSH6- bla KPC-2 , pZSH6- bla NDM-5 and pZSH6- bla CTX-M. [ABSTRACT FROM AUTHOR]

As a platform for enzyme immobilization, metal-organic frameworks (MOFs) can protect enzyme activity from the interference of external adverse environment. Although these strategies have been proven to produce good results, little consideration has been given to the functional similarity of MOFs to the encapsulated enzyme. Here, catalase (CAT) was encapsulated in Fe-BTC with peroxidase-like activity to obtain a stable composite (CAT@Fe-BTC) with synergistic catalytic activity. Depending on the superior selectivity and high catalytic activity of CAT@Fe-BTC, colorimetric sensing for the detection of hydrogen peroxide and phenol was developed. This work demonstrates that the integration of functional MOFs with natural enzyme can be well applied to the construction of efficient catalysts. • MOF with similar functionality to catalase used as an immobilization platform. • The obtained CAT@Fe-BTC composites with synergistic catalytic activity. • The colorimetric sensing platform developed for detecting H2O2 and phenol achieved desired results. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cembranoids were systematically separated by an activity-oriented approach. • Enriched the antifungal, insecticidal, and cytotoxic activities of diverse cembranoids. • Cembranoid activities might be influenced by hydroxyl groups and unsaturation. • Cembranoid kill insects by restraining acetylcholinesterase activity. • Cembranoids are promising for developing bio-pesticides and bio-medicines. Cembranoids are a class of glandular trichome exudates with a variety of structural variations and biological activities, and are found in high quantities in tobacco (Nicotiana tabacum L.). However, few studies have conducted preparative separation and examined the activities of cembranoids other than (1 S ,2 E ,4 S ,6 R ,7 E ,11 E)-2,7,11-cembratriene-4,6-diol (α -CBT-diol, 1) and (1 S ,2 E ,4 R ,6 R ,7 E ,11 E)-2,7,11-cembratriene-4,6-diol (β -CBT-diol, 2); thus, the structure-activity relationship (SAR) of cembranoids remains unclear. Here, to deduce the SAR of cembranoids, raw cembranoid extract was systematically separated through an activity-oriented approach with preparative reversed-phase liquid chromatography. Each fraction was identified, and their antifungal, insecticidal, and cytotoxic bioactivities were evaluated. Composition analysis and activity detection of primary fractions (Fr.1–Fr.10) revealed that cembranoid activity might be influenced by the number of hydroxyl groups and degree of unsaturation (macrocycle and double bonds). Sub-fraction analysis showed that the antifungal activity of cembranoids was related to the number of hydroxyl groups and double bonds, and that their cytotoxic activity was affected by the type and position of substituents. Furthermore, all four factors could influence insecticidal activity. By conducting in-depth studies of single cembranoids, their SARs were summarized. The existence of Δ11,12/Δ7,8 and hydroxylation at C-6/C-4 contributed to the antifungal activity of cembranoids. Variation in the type and position of substituents also significantly affected antifungal activity, of which Δ11,12 was the most influential factor. Additionally, the change in substituent configuration at C-4 and C-12 had no significant effect on antifungal activity. The insecticidal activity of cembranoids benefited from the existence of 4-hydroxyl, which greatly enhanced their binding affinity; however, functional groups substituted at other positions decreased insecticidal activity. Cytotoxic activity was positively correlated with α -configuration at C-4 and hydroxylation at C-6 but inversely correlated with 4-methoxy substitution. Among them, 6-hydroxyl formed the core; the α -/ β -configuration at C-12 and 4-/12-substitution of cembranoids did not affect their insecticidal activity. Insecticidal activity might play a key role by restraining acetylcholinesterase activity through hydrophobic interactions between the cembranoid carbon skeleton and residues located at the acetylcholinesterase binding pocket. These findings may provide a foundation for the development of novel cembranoid-based pesticides and medicines. [ABSTRACT FROM AUTHOR]