Study on the effect of enzymatic treatment of tobacco on HnB cigarettes and microbial succession during fermentation.

Starch and cellulose are the fundamental components of tobacco, while their excessive content will affect the quality of tobacco. Enzymatic treatment with different enzymes is a promising method to modulate the chemical composition and improve the sensory quality of tobacco leaves. In this study, enzymatic treatments, such as amylase, cellulase, and their mixed enzymes, were used to improve tobacco quality, which could alter the content of total sugar, reducing sugar, starch, and cellulose in tobacco leaves. The amylase treatment changed surface structure of tobacco leaves, increased the content of neophytadiene in tobacco by 16.48%, and improved the total smoking score of heat-not-burn (HnB) cigarette products by 5.0 points compared with the control. The Bacillus, Rubrobacter, Brevundimonas, Methylobacterium, Stenotrophomonas, Acinetobacter, Pseudosagedia-chlorotica, and Sclerophora-peronella were found to be significant biomarkers in the fermentation process by LEfSe analysis. The Basidiomycota and Agaricomycetes were significantly correlated with aroma and flavor, taste, and total score of HnB. The results showed that microbial community succession occurred due to amylase treatment, which promoted the formation of aroma compounds, and regulated the chemical composition of tobacco, and improved tobacco quality during tobacco fermentation. This study provides a method for enzymatic treatment to upgrade the quality of tobacco raw materials, thereby improving the quality of HnB cigarettes, and the potential mechanism is also revealed by chemical composition and microbial community analysis. KEY POINTS: Enzymatic treatment can change the chemical composition of tobacco leaves. The microbial community was significantly affected by enzymatic treatment. The quality of HnB cigarettes was significantly improved by amylase treatment.

Enhancement of astaxanthin production from food waste by Phaffia rhodozyma screened by flow cytometry and feed application potential.

Astaxanthin is widely used in food, aquaculture, cosmetics, and pharmaceuticals due to its strong antioxidant activity and coloring ability, but its production from Phaffia rhodozyma remains the main challenge due to the high fermentation cost and low content of carotenoid. In this study, the production of carotenoids from food waste (FW) by a P. rhodozyma mutant was investigated. P. rhodozyma mutant screened by UV mutagenesis and flow cytometry could stably produce high carotenoids at 25°C, with carotenoid production (32.9 mg/L) and content (6.7 mg/g), respectively, increasing by 31.6% and 32.3% compared with 25 mg/L and 5.1 mg/g of wild strain. Interestingly, the carotenoid production reached 192.6 mg/L by feeding wet FW, which was 21% higher than batch culture. The 373 g vacuum freeze-dried products were obtained from the fermentation of 1 kg FW by P. rhodozyma, which contained 784 mg carotenoids and 111 mg astaxanthin. The protein, total amino acids, and essential amino acids content of the fermentation products were 36.6%, 40.5%, and 18.2% (w/w), respectively, and lysine-added fermentation products had the potential of high-quality protein feed source. This study provides insights for the high-throughput screening of mutants, astaxanthin production, and the development of the feed potential of FW.

N6-methyladenosine (m6A) RNA modification in gastrointestinal tract cancers: roles, mechanisms, and applications.

Analogous to DNA methylation and histone modification, RNA modification, as another epigenetic layer, plays an important role in many diseases, especially in tumours. As the most common form of RNA modification, m6A methylation has attracted increasing research interest in recent years. m6A is catalysed by RNA methyltransferases METTL3, METTL14 and WTAP (writers), m6A is removed by the demethylases FTO and ALKBH5 (erasers) and interacts with m6A-binding proteins, such as YT521-B homology (YTH) domain-containing proteins. This article reviews recent studies on methylation modification of m6A in gastrointestinal tract cancers.

Reconstitution of cellulosome: Research progress and its application in biorefinery.

Lignocellulose, one of the most abundant renewable sources of sugar, can be converted into bioenergy through hydrolysis of cellulose and hemicellulose. Due to its renewability and availability in large quantities, bioenergy is considered as a possible alternative to fossil energy and attracts the attention of the world with increased concerns about environmental protection and energy crisis. The depolymerization of cellulosic substrate to monomer is the rate-limiting step in the bioconversion of lignocellulose by cellulolytic microbes. Cellulosome, a multienzyme complex from anaerobic cellulolytic bacteria, can efficiently degrade the cellulosic substrates. Previous studies have shown that the reconstitution of cellulosome in vitro and its heterologous expression or display on the cell surface can help to solve the low yield problem of cellulosome in cellulolytic bacteria. This paper reviews the research progress in the reconstitution of cellulosome as well as its application in biorefinery, including the construction of cellulosome as well as different methods for cellulosome reconstitution and its surface display. This review will promote the understanding of cellulosome and its reconstitution.

Direct hydrogen production from dilute-acid pretreated sugarcane bagasse hydrolysate using the newly isolated Thermoanaerobacterium thermosaccharolyticum MJ1.

BACKGROUND: Energy shortage and environmental pollution are two severe global problems, and biological hydrogen production from lignocellulose shows great potential as a promising alternative biofuel to replace the fossil fuels. Currently, most studies on hydrogen production from lignocellulose concentrate on cellulolytic microbe, pretreatment method, process optimization and development of new raw materials. Due to no effective approaches to relieve the inhibiting effect of inhibitors, the acid pretreated lignocellulose hydrolysate was directly discarded and caused environmental problems, suggesting that isolation of inhibitor-tolerant strains may facilitate the utilization of acid pretreated lignocellulose hydrolysate. RESULTS: Thermophilic bacteria for producing hydrogen from various kinds of sugars were screened, and the new strain named MJ1 was isolated from paper sludge, with 99% identity to Thermoanaerobacterium thermosaccharolyticum by 16S rRNA gene analysis. The hydrogen yields of 11.18, 4.25 and 2.15 mol-H2/mol sugar can be reached at an initial concentration of 5 g/L cellobiose, glucose and xylose, respectively. The main metabolites were acetate and butyrate. More important, MJ1 had an excellent tolerance to inhibitors of dilute-acid (1%, g/v) pretreated sugarcane bagasse hydrolysate (DAPSBH) and could efficiently utilize DAPSBH for hydrogen production without detoxication, with a production higher than that of pure sugars. The hydrogen could be quickly produced with the maximum hydrogen production reached at 24 h. The hydrogen production reached 39.64, 105.42, 111.75 and 110.44 mM at 20, 40, 60 and 80% of DAPSBH, respectively. Supplementation of CaCO3 enhanced the hydrogen production by 21.32% versus the control. CONCLUSIONS: These results demonstrate that MJ1 could directly utilize DAPSBH for biohydrogen production without detoxication and can serve as an excellent candidate for industrialization of hydrogen production from DAPSBH. The results also suggest that isolating unique strains from a particular environment offers an ideal way to conquer the related problems.

Metabolic division of labor between Acetivibrio thermocellus DSM 1313 and Thermoanaerobacterium thermosaccharolyticum MJ1 enhanced hydrogen production from lignocellulose.

In this consortium, DSM 1313 was responsible for degrading lignocellulose by cellulosome, while the highly efficient hydrogen-producing bacterium MJ1 consumed the sugar produced by DSM 1313 to grow and produce more hydrogen. The results showed that the maximum hydrogen production of 259.57 mL/g substrate was obtained at the inoculation ratio (OD600) of 2:1 (DSM 1313:MJ1) and substrate concentration of 10 g/L, 70.84 % higher than pure culture. Furthermore, MJ1 dominated the co-culture system by using various sugars resulting from the biodegradation of substrate, thereby relieving the inhibition of sugar on DSM 1313 and leading to more hydrogen production. In the co-culture system, the value of extracellular oxidation-reduction potential and the ratio of NAD+/NADH was lower than that of pure culture. Additionally, at the gene level, [NiFe]-hydrogenase and [FeFe]-hydrogenase related enzymes were significantly up-regulated, leading to a two-fold increase in hydrogenase activity of co-culture compared with pure culture.

Tobacco microbial screening and application in improving the quality of tobacco in different physical states.

The first-cured tobacco contains macromolecular substances with negative impacts on tobacco products quality, and must be aged and fermented to mitigate their effects on the tobacco products quality. However, the natural fermentation takes a longer cycle with large coverage area and low economic efficiency. Microbial fermentation is a method to improve tobacco quality. The change of chemical composition of tobacco during the fermentation is often correlated with shapes of tobacco. This study aimed to investigate the effects of tobacco microorganisms on the quality of different shapes of tobacco. Specifically, Bacillus subtilis B1 and Cytobacillus oceanisediminis C4 with high protease, amylase, and cellulase were isolated from the first-cured tobacco, followed by using them for solid-state fermentation of tobacco powder (TP) and tobacco leaves (TL). Results showed that strains B1 and C4 could significantly improve the sensory quality of TP, enabling it to outperform TL in overall texture and skeleton of tobacco products during cigarette smoking. Compared with the control, microbial fermentation could increase reducing sugar; regulate protein, starch, and cellulose, reduce nicotine, improve total aroma substances, and enable the surface of fermented TP and TL to be more loose, wrinkled, and porous. Microbial community analysis indicated that strains B1 and C4 could change the native structure of microbial community in TP and TL. LEfSe analysis revealed that the potential key biomarkers in TP and TL were Bacilli, Pseudonocardia, Pantoea, and Jeotgalicoccus, which may have cooperative effects with other microbial taxa in improving tobacco quality. This study provides a theoretical basis for improving tobacco fermentation process for better cigarettes quality.

9-Allyl-9H-carbazole-3,6-dicarbaldehyde.

In the title mol-ecule, C(17)H(13)NO(2), the allyl group is almost perpendicular to the carbazole mean plane, with a dihedral angle of 89.0 (2)°. In the crystal, nonclassical C-H⋯O hydrogen bonds link the mol-ecules into corrugated sheets parallel to the bc plane. Weak inter-molecular π-π inter-actions are observed between the benzene rings [centroid-centroid distance = 3.874 (4) Å] from neighbouring sheets.

Improved methane production with redox-active/conductive biochar amendment by establishing spatial ecological niche and mediating electron transfer.

The multifunctional roles of biochar as an additive in improving the performance of anaerobic digestion (AD) has not been perfectly understood. In this study, the effects of different biochars on AD and the enhanced mechanisms were explored. The CH4 productions were significantly improved with an increase of 45.9%, 28.3% and 16.5% by amendment with biochar pyrolyzed at 300℃ (BC300), 450℃ (BC450) and 600℃ (BC600), respectively. The tightly-bound communities were established on biochar at the initial stage of fermentation and functional microbes were selectively enriched/colonized in biochar-amended systems. Distinctive loosely-bound microbial communities were observed in BC300 and BC600 amended systems, among which electroactive Desulforhabdus and Clostridiales were the dominant bacteria. Biochar amendments also led to the formation of distinctive spatial ecological niches and the selection preference of microbes for specific spatial locations. These results provided new insights in revealing the potential mechanisms of enhanced AD performance by biochar amendment.

Bioaugmentation combined with biochar to enhance thermophilic hydrogen production from sugarcane bagasse.

In this study, Thermoanaerobacterium thermosaccharolyticum MJ2 and biochar were used to enhance thermophilic hydrogen production from sugarcane bagasse. MJ2 bioaugmentation notably increased the hydrogen production by 95.31%, which was further significantly improved by 158.10% by adding biochar. The addition of biochar promoted the degradation of substrate, improved the activities of hydrogenase and electron transfer system, and stimulated microbial growth and metabolism. Microbial community analysis showed that the relative abundance of Thermoanaerobacterium was significantly increased by bioaugmentation and further enriched by biochar. PICRUSt analysis showed that MJ2 combined with biochar promoted metabolic pathways related to substrate degradation and microbial metabolism. This study provides a novel enhancement method for hydrogen production of the cellulolytic microbial consortium by exogenous hydrogen-producing microorganism combined with biochar and deepens the understanding of its functional mechanism.

Analysis of N6-Methyladenosine Methylome in Adenocarcinoma of Esophagogastric Junction.

Background: From previous studies, we found that there are more than 100 types of RNA modifications in RNA molecules. m6A methylation is the most common. The incidence rate of adenocarcinoma of the esophagogastric junction (AEG) at home and abroad has increased faster than that of stomach cancer at other sites in recent years. Here, we systematically analyze the modification pattern of m6A mRNA in adenocarcinoma at the esophagogastric junction. Methods: m6A sequencing, RNA sequencing, and bioinformatics analysis were used to describe the m6A modification pattern in adenocarcinoma and normal tissues at the esophagogastric junction. Results: In AEG samples, a total of 4,775 new m6A peaks appeared, and 3,054 peaks disappeared. The unique m6A-related genes in AEG are related to cancer-related pathways. There are hypermethylated or hypomethylated m6A peaks in AEG in differentially expressed mRNA transcripts. Conclusion: This study preliminarily constructed the first m6A full transcriptome map of human AEG. This has a guiding role in revealing the mechanism of m6A-mediated gene expression regulation.

Visual Navigation and Landing Control of an Unmanned Aerial Vehicle on a Moving Autonomous Surface Vehicle via Adaptive Learning.

This article presents a visual navigation and landing control paradigm for an unmanned aerial vehicle (UAV) to land on a moving autonomous surface vehicle (ASV). Therein, an adaptive learning navigation rule with a multilayer nested guidance is designed to pinpoint the position of the ASV and to guide and control the UAV to fulfill horizontal tracking and vertical descending in a narrow landing region of the ASV by means of merely relative position feedback. To ensure the feasibility of the proposed control law, asymptotical stability conditions are derived based on Lyapunov stability theory. Landing experimental results are reported for a UAV-ASV system consisting of an M-100 UAV and a self-developed three-meters-long HUSTER-30 ASV on a lake to substantiate the efficacy of the proposed landing control method.

Smart MMP2-Responsive Nanoprobe for Activatable Fluorescence Imaging-Guided Local Triple-Combination Therapies with Single Light.

Elaborately designed stimuli-responsive smart systems simultaneously enabling activatable imaging and selective treatment are highly desirable for precise diagnosis and therapy of cancer. Herein, such a smart theranostic nanoprobe composed of hollow gold nanospheres (HAuNs), photosensitizer (PS), matrix metalloproteinase 2 (MMP2) substrate peptide, and model drug doxorubicin (DOX) was designed. In the design, HAuNs served as the acceptor of Förster resonance energy transfer (FRET), photothermal therapy (PTT) reagent, and nanocarrier. The fluorescence and 1O2 generation of PS were inhibited by HAuNs through FRET effect, avoiding phototoxicity to normal tissues during circulation. Meanwhile, owing to the MMP2-triggered peptide cleavage, the PS could be efficiently activated in a tumor for selective fluorescence imaging and photodynamic therapy (PDT). The recovered fluorescence could be applied for detecting MMP2, locating tumor in vivo, and further guiding the local triple-combination therapies including PDT, PTT, and chemotherapy. The synergistic treatments of activated PDT, PTT, and controlled DOX release were achieved with single light, which provided the best therapeutic effects with enhanced stability and remarkably reduced nonspecific toxicity of PS and anticancer drug. This study helps to design novel stimuli-responsive systems for precise molecular sensing and site-specific cancer treatment.

9-n-Butyl-9,9'-bi[9H-fluorene].

In the title compound, C(30)H(26), the dihedral angle between the two fluorene ring systems is 61.75 (4)°.

9-Chloro-methyl-9-[(9H-fluoren-9-yl)meth-yl]-9H-fluorene.

In the title compound, C(28)H(21)Cl, the dihedral angle between the two fluorene ring systems is 71.97 (4)°. There is an intra-molecular C-H⋯Cl hydrogen bond. In the crystal structure, the centroid-to-centroid distance between stacked fluorene ring systems is ca 4.22 Å, which indicates that there are no π-π stacking inter-actions between them.

Conventional real-time PCR-based detection of T790M using tumor tissue or blood in patients with EGFR TKI-resistant NSCLC.

Blood biopsy has many advantages over tissue biopsy for diagnosing acquired T790M mutation in patients with non-small-cell lung cancer, such as being less risky and painful. New techniques with high sensitivity (eg, droplet digital PCR) show promising results during blood biopsy, but the positive rates of identification are still quite unclear. Whether there are other factors, except technology, affecting the results of blood biopsy is unclear. In this study, we used conventional amplification refractory mutation system to detect tumor tissue or blood for T790M mutation in patients clinically resistant to tyrosine kinase inhibitors. A total of 45 patients treated at West China Hospital between 2014 and 2016 were analyzed. The positive rate of T790M mutation was 70.8% based on tissue biopsy and 37.5% based on blood biopsy. Of the 24 patients whose epidermal growth factor receptor gene was genotyped through tissue and blood biopsy, 10 (41.7%) were concordant for T790M mutation status (κ=0.006). Of the 17 patients positive for T790M by tissue biopsy, 7 (41.2%) were positive for T790M by blood biopsy, and 3 of these 7 were only weakly positive. Of the 7 patients negative for T790M by tissue biopsy, 2 (28.6%) were positive by blood biopsy. Our T790M detection rate is higher than that reported by other studies using digital droplet PCR. These results suggest that other factors (eg, clinical features), intrinsically connected with circulating tumor DNA level, also affect the results of blood biopsy, and thus cannot be controlled through technological optimization.

The phase transformation of CuInS2 from chalcopyrite to wurtzite.

In the present work, CuInS2 nanoparticles have been successfully synthesized by water-bath method with deionized water as solvent and thioglycolic acid as complexing agent at 80°C. The phase transition of CuInS2 from chalcopyrite to wurtzite was realized by adjusting the pH value of reaction solution. The emergence of Cu2S in the condition of higher pH value of reaction solution led to the formation of wurtzite CuInS2. This facile method that controls the phase structure by adjusting the solution pH value could open a new way to synthesize other I-III-VI2 ternary semiconductor compounds.

Controllable fabrication of patterned ZnO nanorod arrays: investigations into the impacts on their morphology.

Fabricating ZnO nanorod arrays with precisely controlled morphology, alignment, and density is highly desirable but rather challenging. On the other hand, understanding the parameters that affect their final morphology and the growth mechanisms is significant to integrate such patterned ZnO nanorod arrays in various applications. Therefore, ZnO nanorod arrays with different density and morphology were fabricated by electron beam lithography (EBL) combined with the hydrothermal methods in this work. The influences of prepatterned geometry and the growth parameters such as seed layer, the precursor concentration, and the growth time on their final morphology were investigated. Under the coactions of EBL and the subsequent hydrothermal growth, ZnO nanorod arrays with precisely controlled density, position and morphology were achieved. The growth mechanism was also discussed in detail for the ZnO nanorod arrays which confined by the aperture with different size.