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The new organic hybrid indium–telluride [In2(ea)2Te2]n(1; Hea = ethanolamine) exhibits a new type of one-dimensional polymeric chain based on the linkages of dinuclear [In2(ea)4]2+and [In2Te4]2–units, which offers the first example of an indium–telluride framework incorporating binuclear complexes [In2(ea)4]2+with a bridging O donor. 1shows a distinctive photocurrent response and photocatalytic properties under visible-light illumination.

Both 1,2,4-trisubstitution and dearomative 1,2,4-trifunctionalization of benzyne have been accomplished from sulfoxides bearing a penta-2,4-dien-1-yl moiety. These cascade transformations proceed through a benzyne insertion into the S═O bond and an uncommon regiospecific anionic [4,5]-sigmatropic rearrangement, furnishing a C–O, C–S, and C–C bond on the C1-, C2-, and C4-position of a benzene ring, respectively. This study showcases new cascade benzyne reaction modes involving both distal C–H bond functionalization and dearomatization.

The varying degrees of browning due to the Maillard reaction result in distinct characteristics across different parts within the cross-section of Houhuo low-temperature Daqu (LTD). However, the microbial community structure of the peel and core of Daqu is still poorly understood. In this study, using a combination of high-throughput sequencing and pure culture techniques, the microbial communities present in the peel and core of Houhuo LTD were compared and analyzed. Bacillus(58.84%) and Saccharomycopsis(87.61%) were the main bacterial and fungal genera present in Houhuo LTD. The abundance and diversity of fungi were significantly lower in peel samples (P < 0.01). At the bacterial genus level, Sphingobium, Staphylococcus, and Streptomyceswere significantly enriched in peel samples, while Saccharopolysporawas significantly enriched in core samples (P < 0.05). At the fungal genus level, Saccharomycopsisand Clavisporawere significantly enriched in peel samples, while Monascusand Aspergilluswere significantly enriched in core samples (P < 0.05). Differences in the layers of LTD block had a greater effect on the correlation between bacterial genera, and the microbial networks in the peel samples were more compact. Some microbial groups were common to the two groups, including the main bacterial genera Bacillus, Saccharopolyspora, Streptomyces, and Staphylococcusand the main fungal genera Saccharomycopsisand Monascus. Pure culture techniques revealed that B. paralicheniformis, Pediococcus pentosaceus, and S. fibuligerawere the most abundant strains of Bacillus, lactic acid bacteria, and yeast in all samples, respectively. The findings could support the optimization of the Daqu-making processes and the screening of microbial strains for brewing.

Although benzyne has been well-known to serve as a synthon that can conveniently prepare various 1,2-difunctionalized benzenes, the sites other than its formal triple bond remain silent in typical benzyne transformations. An unprecedented aryne 1,2,3,5-tetrasubstitution was realized from 3-silylbenzyne and aryl allyl sulfoxide, the mechanistic pathway of which includes a regioselective aryne insertion into the S═O bond, a [3,6]-sigmatropic rearrangement, and a thermal aromatic 1,3-silyl migration cascade.

Stacked fermentation is the process of utilizing microorganisms in the environment and further enriching their population in Jiupei. However, the composition of microbial communities in the different layers of Jiupei and their relationship with sensory quality requires more clarity. This study analyzed the microbial composition of the different layers of Jiupei in the fourth round of stacked fermentation using high-throughput sequencing technology. Physicochemical properties and sensory qualities were measured; the correlation between the observed microorganisms and sensory quality was further analyzed. The results showed that there were significant differences in acidity, moisture, starch, reducing sugar, and protein content across the different layers of the Jiupei (P < 0.05). The flavor substances in the entire Jiupei dump primarily included organic sulfides, terpenes, and ethanol, and umami was the most dominant taste indicator. Significant differences in microbial community structure were observed across the layers of the Jiupei, with the main bacterial genera being Thermoactinomyces(63.95%), and Bacillus(11.77%). Meanwhile, the main fungal genera identified were Pichia(28.37%), Saccharomyces(24.42%), and Byssochlamys(17.01%). The correlation between the microorganisms and the sensory indexes in Jiupei was found to be significant (P < 0.05); the presence of the bacterial genera Bacillusand Thermoactinomycesand the fungal genera Saccharomyces, Byssochlamys, and Zygosaccharomyceswas found to be related to the sensory quality of Jiupei. This study provides insights into the role of microorganisms in the fourth round of liquor fermentation and provides a theoretical reference for the subsequent optimization of sauce-flavor liquor quality.

In this study, the physicochemical characteristics and bacterial community structure of Yunmen medium-high temperature Daqu were investigated. At the same time, the bacterial community structures of medium-high temperature Daqu from Yunmen and Yingtan were compared and analyzed. The results showed that Yunmen medium-high temperature Daqu was rich in culturable bacteria, and the highest number of Bacillus amyloliquefaciens(33.33 %). The moisture content (8.28 % ± 0.62 %) of Yunmen medium-high temperature Daqu was low, but its acidity (9.26 ± 2.08 mmoL/10 g) and starch content (66.20 % ± 2.80 %) were high, which were related to the relative abundance of Latilactobacillus, Companilactobacillus, Weissella, and Bacillus. Compared with Yingtan medium-high temperature Daqu, the significantly lower Shannon index and Simpson index (P < 0.05); the weaker correlation between bacterial networks, especially positive correlation; and the lower relative abundance of core bacterial communities of Yunmen medium-high temperature Daqu. Overall, this study evaluated the quality of Yunmen medium-high temperature Daqu and revealed the bacterial community structure of medium-high temperature Daqu from two different regions. The results could guide the future exploration of fermentation mechanisms in medium-high temperature Daqu.

Rice wine koji is made from “ChengQu” as the parent species and is prepared by enriching microorganisms in the environment, which plays a decisive role in the formation of quality rice wine. This study explored the microbiome of 18 rice wine koji collected from Xiaogan, Fangxian, Hubei, Dazhou, and Sichuan and analyzed the sensory quality and microbiome of rice wine made with rice koji as a fermentation agent. Although our results showed that there were large differences in microbial communities and functions in rice wine koji, samples from the same region had a higher similarity, and the closer the distance, the higher the similarity. Five suspected new species (Lactococcussp., Weissellasp., Lactobacillussp., and Acetobactersp.) were discovered by ultra-high-depth metagenomic sequencing; their functional maps and phase correlation analysis showed that they contributed positively to the aroma of rice wine. The sensory quality and microbial community structure of rice wine fermented with different rice wine koji have obvious differences, consistent with the structural difference of microorganisms in rice wine koji in different regions. These findings indicate that rice wine koji directly determines the structure of microorganisms in rice wine and directly or indirectly affects the sensory quality of rice wine.

Palladium‐catalyzed transformation reactions of unsaturated molecules have considerable importance because of their versatility and wide range of applications. Over the past decades, various experimental studies on palladium‐catalyzed unsaturated bond transformation have been reported, and mechanistic and computational studies have also progressed considerably. With the development of computing methods and power, theoretical calculation has become a powerful tool for mechanistic study of transition‐metal catalysis. In this review, we summarize the literature on mechanistic studies of palladium‐catalyzed transformations of unsaturated molecules, including hydrogenation, alkylation, arylation, silylation, vinylation, cyclization and esterification. Mechanistically, most of these reactions undergo a redox pathway, involving either oxidative addition, insertion, transmetalation, β‐H elimination or reductive elimination. Some instead undergo a non‐redox pathway, mainly involving insertion or β‐H elimination. In this review, recent reports on mechanistic studies of palladium‐catalyzed transformations of unsaturated molecules, including hydrogenation, alkylation, arylation, silylation, vinylation, cyclization and esterification of alkenes, alkynes, imines, carbonyls, arenes, carbenes and nitrenes have been summarized.

DFT calculations are used to reveal the mechanism of Brønsted-base-mediated borylation of propynols. The reaction is predicted to go through a key intermediate of alkenylboronate. Therefore, the possible pathways involve two key steps, borylation and reductive dehydroxylation. The favored pathway for the generation of the alkenylboronate intermediate involves alkoxy exchange, methoxylation, electrophilic substitution, and protonation. Then, the final product is yielded by a second alkoxy exchange, intramolecular nucleophilic attack, β-methoxy elimination, and protonation.

Terminal alkynes have become one of the most versatile building blocks for C–C bond construction in the past few decades, and they are usually considered to convert to acetylides before further transformations. In this study, a novel direct nucleophilic addition mode for Cu(I)-catalyzed cross-coupling of terminal alkynes and N-tosylhydrazones to synthesize chiral allenes is proposed, and it was investigated by density functional theory with the M11-L density functional. Three different reaction pathways were considered and investigated. The computational results show that the proposed reaction pathway, which includes direct nucleophilic attack of protonated acetylene, deprotonation of the vinyl cation, and catalyst regeneration, is the most favorable pathway. Another possible deprotonation–carbenation–insertion pathway is shown to be unfavorable. The direct nucleophilic addition step is the rate- and enantioselectivity-determining step in the catalytic cycle. Noncovalent interaction analysis shows that the steric effect between the methyl group of the carbene moiety and the naphthalyl group of the bisoxazoline ligand is important to control the enantioselectivity. In addition, calculation of a series of chiral bisoxazoline ligands shows that a bulky group on the oxazoline ring is favorable for high enantioselectivity, which agrees with experimental observations. Moreover, copper acetylides are stable, and their generation is a favorable pathway in the absence of chiral bisoxazoline ligands.

AbstractCalcium-dependent protein kinase (CDPK) plays an important role in plant resistance to disease. In this study, we assessed CDPK activity in Hami melons during Penicilliuminfection, in order to investigate the possible role of CDPK in this context. The results showed the induction of CDPK by Penicilliuminfection may contribute to the early stages of disease resistance in Hami melons. In order to further study the molecular mechanisms underlying this response, relatively high expression of HmCDPK1was screened form the transcriptome database of Hami melons. Bioinformatics analysis showed HmCDPK1had a length of 2365 bp, with a maximum open reading frame of 1560 nucleotides, encoding 519 amino acids with a molecular weight of 58,646.83. Moreover, its theoretical isoelectric point was 6.34, as a hydrophilic and non-transmembrane protein. Real-time quantitative PCR showed the transcript of HmCDPK1was persistently increased after Penicilliuminfection and reached its maximum at 12 h, being significantly higher than in non-infected plants. These results suggest the induction of CDPK activity and HmCDPK1expression in the early response of Hami melons to Penicilliummay contribute to the resistance against this infection.

This report describes the oxidative cyclopalladation activation of a CC bond during the Pd-catalyzed hydroalkylation of alkynes and analyzes potential reaction pathways based on density functional theory calculations. The more favorable pathway in-volves an oxidative cyclopalladation to generate a palladacyclopropene intermediate, which is rarely examined in Pd-catalyzed alkyne transformations. The reaction pathway proposed herein is kinetically favorable relative to the commonly proposed alkyne insertion mode. Furthermore, the Laplacians of the electron density, interaction region indicators, Mayer bond orders, and localized orbital bonding are evaluated to determine the reaction processes and characterize the key intermediates. Theoretical calculations indicate covalent bonding between a Pd(II) center and the two C-atoms in three-membered palladacycle species. Finally, electrostatic potential analysis reveals that the regioselectivity is governed by the charge distribution on the palladacycle moiety during the protonation step.

Low-temperature storage is frequently employed to prolong the shelf life of Hami melons. Nevertheless, extended low-temperature storage can hamper the synthesis of aroma compounds in these fruits. This study investigated the effects of storage at 3 °C (LT) and 21 °C (RT) on the aroma quality of Golden Empress Hami melons (GEHMs) during a shelf life of 24 d. Further, the transcription levels of genes related to aroma metabolism were also examined during this period. After 12 d, the intensity of sweet aroma (LT: 2.3, RT: 8.2) and fruit aroma (LT: 2.1, RT: 8) was significantly lower in GEHMs stored at LT than in those stored at RT. Correspondingly, between-group differences in the content of esters with sweet and fruity aromas (RT: 782.76 ± 128.41 μg/kg, LT: 53.69 ± 24.32 μg/kg) and alcohols (RT: 2252.98 ± 297.65 μg/kg, LT: 448.80 ± 106.13 μg/kg) peaked at 12 d. Furthermore, the expression levels of 52 genes related to aroma volatile biosynthesis were significantly different between GEHMs stored at RT and LT. Specifically, the expression levels of genes encoding ethanol dehydrogenase (ADH), long-chain acyl-CoA synthetase (ACSL), and branched-chain amino acid aminotransferase (ilvE) which are involved in the production of alcohols and esters— were significantly lower in GEHMs stored at LT than in those stored at RT. This study provides a deeper understanding of aroma-related biosynthetic pathways of GEHMs during postharvest storage. Additionally, it offers valuable metabolomic and transcriptomic resources for the regulation of aroma compound metabolism in postharvest GEHMs.

AbstractPhenol adsorption experiments were conducted at constant temperature under oscillation conditions. The effects of the initial concentration of the aqueous phenol solution, temperature, adsorbent dosage, and initial pH of the solution on the removal rate were investigated. For an initial concentration of the aqueous phenol solution in the range 25–200 mg/L, a temperature of 40°C, a neutral solution, and a ratio of adsorbent/phenol in the range 40:1 to 2.5:1, the removal rate of phenol was 97% or more. The adsorption isotherm of phenol with MOF-5 followed the Langmuir and Freundlich models, with relative coefficients of 0.9855 and 0.9960, respectively. The adsorbent was recycled by soaking and washing with ethanol, and the recycled adsorbent gave good results after being reused six times.

Phenol adsorption experiments were conducted at constant temperature under oscillation conditions. The effects of the initial concentration of the aqueous phenol solution, temperature, adsorbent dosage, and initial pH of the solution on the removal rate were investigated. For an initial concentration of the aqueous phenol solution in the range 25–200 mg/L, a temperature of 40°C, a neutral solution, and a ratio of adsorbent/phenol in the range 40:1 to 2.5:1, the removal rate of phenol was 97% or more. The adsorption isotherm of phenol with MOF-5 followed the Langmuir and Freundlich models, with relative coefficients of 0.9855 and 0.9960, respectively. The adsorbent was recycled by soaking and washing with ethanol, and the recycled adsorbent gave good results after being reused six times.

Sea buckthorn has been proved to be a good substrate for lactic acid bacteria (LAB), but the research on the fermentation of sea buckthorn juice (SBJ) by LAB is still rare. This study was designed to determine the performance of fermented SBJ (FSBJ) in four LAB and investigate the sensory aspects of FSBJ. The results showed that the utilization rates of reducing sugar, titratable acid, and malic acid of SBJ fermented by Lactobacillus casei(SBJLc) were the highest and that lactic acid content was the greatest. The organic acid compositions of the four kinds of FSBJs were also different. The viable counts of all FSBJs was greater than 7 log CFU/mL, and that the viable count of SBJ fermented by SBJLc was the highest. In this study, the Electronic tongue combined with Electronic nose was used for the first time to study SBJ. Results showed that compared with the control, the response value of Sourness was significantly increased, while Bitterness and Astringency were significantly decreased. There was a significant difference in four FSBJs. The results of the electronic nose showed that SBJ fermented by Lactobacillus plantarumLP56 (SBJLp) could be well identified by sensors sensitive to aromatic substances. The volatile compound contents before and after fermentation were significantly different, the highest being SBJLp. Finally, the results of sensory evaluation experiments showed that SBJLp was the most acceptable to consumers in terms of sensory evaluation.

Zha-chili is a traditional Chinese fermented food, made by rice-flour or corn-flour with the chopped red chili. Over the years, it has played an important role in Hubei cuisine, but its precise bacterial profiles still remain unclear. In this study, the bacterial compositions of 28 zha-chili samples were determined by SMRT sequencing of the full-length 16S rRNA gene. Subsequently, E-nose, E-tongue and MSS sequencing were applied to evaluate the flavor and microbial metagenome of the zha-chili samples. The SMRT sequencing results revealed 425 bacterial species of 220 genera, belonging to 11 phyla, and 3 robust clusters (hereafter referred to as types) were identified. The most abundant species in zha-chili samples were considerably more Lactobacillusspecies, but sizable bacterial composition differences were also revealed across zha-chili sample types, for instance, a significant difference in Lactobacillus acetotoleranspresence among 3 types samples. The results showed that the bacterial communities inside type I samples were complex and markedly differ from those of type II and type III. Negative correlations were found between NaCl content and Lactobacillusat genus level, and Lactobacillus acetotoleransat species level. These results indicate that NaCl content may contribute to the identified of specific bacterial types and affect the ecological succession of the bacterial communities during the fermentation process. The dominant bacterial species in zha-chili samples were extremely significantly correlated with aroma, but not with taste. In addition, 4 dominate KEGG pathways have been discovered, including metabolism, genetic information processing, environmental information processing and cellular processes.