Targeted metabolomics analysis based on HS-SPME-GC-MS to discriminate geographical origin of 'Muscat Hamburg' grape and wine.

Monoterpenes are typical aroma components in muscat grapes and wines, closely related to its geographical origins. However, the mechanism underlying the geographical differences of monoterpenes remains to be elucidated, especially in the Chinese viticulture regions. This study investigated the diversity of six Chinese viticultural vineyards (YT, XF, SS, XX, WW and CL) in the monoterpene composition of Vitis vinifera L. cv.'Muscat Hamburg' grapes and the resulted wines. Monoterpenes were analyzed by HS-SPME- GC-MS. The total amount of free and bound monoterpenes varied dramatically between grapes of different vineyards, and their contents were obviously higher in YT region grapes. The OAVs for 18 monoterpenes of grapes from the YT vineyard were relative higher than those of other regions, and the floral odor could distinguish grapes from different regions. The total free monoterpenes were highest in the YT region wine. Concentrations of total bound monoterpenes ranged from 711.13 µg/L (XF region) to 1078.30 µg/L (CL region). A correlation analysis showed that all monoterpenes showeda positive correlation with mean relative humidity, sum rainfall, and a negative correlation with sum duration of sunshine and mean temperature. This study would provide some new insights to understand the geographical differences of monoterpenes, and the results would facilitate the effective viticultural treatment of grapes to improve the quality of the aroma.

A study of the pesticide residues in rapeseeds in China: Levels, distribution and health risk assessment.

The aim of this survey was to evaluate the residue levels, distribution and exposure risk of the 38 most commonly used pesticides in rapeseed samples collected from the main production areas in China over a two-year period. The sampling area covered 12 provinces, including Guizhou, Shaanxi, Yunnan, Hunan, Jiangxi, Sichuan, Chongqing, Anhui, Henan, Hubei, Zhejiang, and Jiangsu provinces. The pesticide residues were determined using a QuEChERS (Quick Easy Cheap Effective Rugged and Safe) method coupled with gas chromatography-tandem mass spectrometry and liquid chromatography-tandem mass spectrometry. 8.4% of the rapeseed samples contained pesticides with a residue level ranging from 0.001 to 0.634 mg/kg. The detected analytes were imidacloprid, quizalofop-P-ethyl, thiamethoxam, paclobutrazol, prochloraz, tebuconazole, difenoconazole, s-metolachlor, carbofuran, and carbendazim. The concentrations of four analytes, including thiamethoxam, difenoconazole, carbendazim and prochloraz, exceeded the maximum residue level set by the Chinese government for rapeseed, with exceedance rates of 0.1%, 0.1%, 0.1%, and 1.1%, respectively. Based on the index of quality for residues (IqR) values, 91.6% of the total rapeseed samples had an IqR category of Excellent (IqR = 0). Only 1.5% of the tested samples were of inadequate quality. Furthermore, the assessment of chronic and acute exposure, as well as health risks associated with pesticide residues in rapeseed, was conducted for different age groups within the Chinese population, including adults (6-14 years), children (15-49 years), and the elderly (50-74 years). The results of this assessment indicated that pesticide residues in rapeseed cultivated in China are not expected to be of short- or long-term risks to the Chinese customers.

Coordination as inference in multi-agent reinforcement learning.

The Centralized Training and Decentralized Execution (CTDE) paradigm, where a centralized critic is allowed to access global information during the training phase while maintaining the learned policies executed with only local information in a decentralized way, has achieved great progress in recent years. Despite the progress, CTDE may suffer from the issue of Centralized-Decentralized Mismatch (CDM): the suboptimality of one agent's policy can exacerbate policy learning of other agents through the centralized joint critic. In contrast to centralized learning, the cooperative model that most closely resembles the way humans cooperate in nature is fully decentralized, i.e. Independent Learning (IL). However, there are still two issues that need to be addressed before agents coordinate through IL: (1) how agents are aware of the presence of other agents, and (2) how to coordinate with other agents to improve joint policy under IL. In this paper, we propose an inference-based coordinated MARL method: Deep Motor System (DMS). DMS first presents the idea of individual intention inference where agents are allowed to disentangle other agents from their environment. Secondly, causal inference was introduced to enhance coordination by reasoning each agent's effect on others' behavior. The proposed model was extensively experimented on a series of Multi-Agent MuJoCo and StarCraftII tasks. Results show that the proposed method outperforms independent learning algorithms and the coordination behavior among agents can be learned even without the CTDE paradigm compared to the state-of-the-art baselines including IPPO and HAPPO.

Distributed time-varying optimization control protocol for multi-agent systems via finite-time consensus approach.

This paper addresses a distributed time-varying optimization problem with inequality constraints based on multi-agent systems over switching communication graphs. To reduce the influence of time-varying inequality constraints, an exact penalty method and smoothing technique are employed. Then, a Hessian-based distributed control protocol is presented to seek the time-varying optimal solution of the distributed time-varying optimization problem by virtue of only local information and interaction. It is shown that all agents not only achieve finite-time consensus but also track the time-varying global optimal target eventually. Compared with the existing distributed optimization protocols, the proposed control protocol is suitable for more general distributed time-varying optimization problems and enjoys high-efficiency convergence. Finally, numerical examples and experiment on moving target tracking of Unmanned Aircraft Vehicle (UAV) are performed to illustrate the effectiveness of the proposed control protocol.

Pharmaceutical Manipulation of Mitochondrial F0F1-ATP Synthase Enables Imaging and Protection of Myocardial Ischemia/Reperfusion Injury Through Stress-induced Selective Enrichment.

To rescue ischemic myocardium from progressing to myocardial infarction, timely identification of the infarct size and reperfusion is crucial. However, fast and accurate identification, as well as the targeted protection of injured cardiomyocytes following ischemia/reperfusion (I/R) injury, remain significantly challenging. Here, a near infrared heptamethine dye IR-780 is shown that has the potential to quickly monitor the area at risk following I/R injury by selectively entering the cardiomyocytes of the at-risk heart tissues. Preconditioning with IR-780 or timely IR-780 administration before reperfusion significantly protects the heart from ischemia and oxidative stress-induced cell death, myocardial remodeling, and heart failure in both rat and pig models. Furthermore, IR-780 can directly bind to F0F1-ATP synthase of cardiomyocytes, rapidly decrease the mitochondrial membrane potential, and subsequently slow down the mitochondrial energy metabolism, which induces the mitochondria into a "quiescent state" and results in mitochondrial permeability transition pore inhibition by preventing mitochondrial calcium overload. Collectively, the findings show the feasibility of IR-780-based imaging and protection strategy for I/R injury in a preclinical context and indicate that moderate mitochondrial function depression is a mode of action that can be targeted in the development of cardioprotective reagents.

Combined ultrasound and low temperature pretreatment improve the content of anthocyanins, phenols and volatile substance of Merlot red wine.

Ultrasound combined with low temperature treatment is a new food processing technology. In this study, low temperature, three ultrasound power levels, and their combinations were adopted in the must before fermentation to study their effects on Merlot red wine. The results showed that ultrasound combined with low temperature pretreatment increased the total and monomer contents of anthocyanins and phenols, affected the color of the wine, and significantly increased its antioxidant capacity. In particular, 240 W of ultrasound combined with low temperature pretreatment reduced the bad odors (caprylic acid, benzaldehyde, and 1-ethanol content) and improved the flower and fruit aroma (1-octanol and phenethyl acetate), as well as the aftertaste, thus improving the quality of the wine. Ultrasound combined with low temperature pretreatment positively affected the quality of Merlot red wine.

Approach for quick exploration of highly effective broad-spectrum biocontrol strains based on PO8 protein inhibition.

Aflatoxin is a group of strongly toxic and carcinogenic mycotoxins produced by Aspergillus flavus and other Aspergillus species, which caused food contamination and food loss problems widely across the world especially in developing countries, thus threatening human health and sustainable development. So, it is important to develop new, green, and broad-spectrum biocontrol technology for the prevention of aflatoxin contamination sources. Previously, we found that the PO8 protein from aflatoxigenic A. flavus could be used as a biomarker to predict aflatoxin production in peanuts (so the PO8 is named as an early warning molecule), which infers that the PO8 is relative to aflatoxin production. Therefore, in the study, based on inhibiting the PO8, a new and quick strategy for screening aflatoxin biocontrol strains for developing control agents was presented. With the PO8 inhibition method, four biocontrol strains (2 strains were isolated from peanut kernels with sterilized surface and another 2 strains from peanut rhizosphere soil) were selected and combined to increase prevention wide-spectrum. As a result, the combination showed over 90% inhibition to all tested aflatoxigenic A. flavus isolated from three different peanut production areas (north, middle, and south areas of China), and better than any single strain. The field experiments located in five provinces of China showed that the practice prevention effects (inhibition of aflatoxigenic fungi on the surface of the peanuts) were from 50% to over 80%. The results indicated that the strategy of inhibiting the early warning molecule PO8 can be used to develop aflatoxin control agents well.

Evolution of green leaf volatile profile and aroma potential during the berry development in five Vitis vinifera L. Cultivars.

Green leaf volatiles (GLVs), play important roles in the green and fresh aroma characteristics of grape berries. The evolution of GLV profiles regarding the varietal difference during grapevine phenological ripening is not well understood. This study generated the GLV profiles of five Vitis vinifera L. cultivars ('Cabernet Sauvignon,' 'Cabernet Franc,' 'Cabernet Gernischt,' 'Chardonnay,' and 'Sauvignon Blanc') at five ripening stages. GLVs were distinctive at different E-L stages for each grape variety. (E)-2-hexen-1-ol, 1-hexanol, and hexanal were the dominant components in all mature berries. In terms of total GLV content, all varieties reached the maximum at maturity in the 2019 vintage, and the total GLV content was higher in mature Sauvignon Blanc and Cabernet Sauvignon grapes. In the 2020 vintage, the total GLV content in Chardonnay and Sauvignon Blanc berries rapidly accumulated at veraison and peaked before harvest. The present results could help winemakers create a good balance of wine aroma.

Integrated metabolomic and transcriptomic analysis reveals the mechanism underlying the accumulation of anthocyanins and other flavonoids in the flesh and skin of teinturier grapes.

Vitis vinifera 'Yan73' is a teinturier grape cultivar with red flesh. To explore the mechanism of berry color development, we performed an integrated flavonoid-targeted analysis of the metabolome and transcriptome of the skin and flesh of Yan73 berries collected at three phenological stages (E-L 31, E-L 35, and E-L 38). We identified 234 flavonoid-related metabolites, including 61 flavonols, 22 anthocyanins, and 61 other flavonoids. Most flavonoid metabolites accumulated continuously during berry development and attained the highest contents in the skin at E-L 38. The transcript level of crucial genes (C4H, CHS, and GST) was highest in the skin at E-L 38. Seventeen distinct modules were identified in a weighted gene correlation network analysis. The MEcoral1 module was probably correlated with flavonoid metabolism and comprised 623 unigenes. The findings provide insights into the regulation of flavonoid metabolites during berry development of Yan73 grape.

Hyperbaric oxygen enhanced the chemotherapy of mitochondrial targeting molecule IR-780 in bladder cancer.

BACKGROUND: Bladder cancer has a high rate of recurrence and drug resistance due to the lack of effective therapies. IR-780 iodide, a near-infrared (NIR) mitochondria-targeting fluorescent agent, has been demonstrated to achieve higher selectivity than other drugs in different tumor types and exhibited tumor-killing effects in some cancers. However, this therapeutic strategy is rarely studied in bladder cancer. MATERIAL AND METHODS: The accumulation of IR-780 in bladder cancer was measured by NIR imaging. Human bladder cell lines (T24, 5637, and TCCSUP) were treated with IR-780 or combined IR-780 and hyperbaric oxygen (HBO). Cell viability, cell apoptosis, cellular ATP production, mitochondrial reactive oxygen species (ROS), and plasma membrane potential were detected. Mitochondrial complex I protein NDUFS1 was measured by western blot. To confirm the anti-tumor efficacy of IR-780 + HBO, mouse bladder cell line (MB49) tumor-bearing mice were established and tumor size and weight were recorded. Besides, cell apoptosis and tumor size were assessed in drug-resistant bladder cancer cells (T24/DDP) and xenografts to evaluate the effect of IR-780 + HBO on drug-resistant bladder cancer. RESULTS: IR-780 selectively accumulated in bladder cancer (bladder cancer cells, transplanted tumors, and bladder cancer tissue from patients) and could induce cancer cell apoptosis by targeting the mitochondrial complex I protein NDUFS1. The combination with HBO could significantly enhance the anti-tumor effect of IR-780 in vitro by promoting cancer cell uptake and inducing excessive mitochondrial ROS production, while suppressing tumor growth and recurrence in animal models without causing apparent toxicity. Moreover, this combination antitumor strategy was also demonstrated in drug-resistant bladder cancer cells (T24/DDP) and xenografts. CONCLUSION: We identified for the first time a combination of IR-780 and HBO (IR-780 + HBO), which exhibits mitochondria-targeting and therapeutic capabilities, as a novel treatment paradigm for bladder cancer.

Mass spectrometry in food authentication and origin traceability.

Food authentication and origin traceability are popular research topics, especially as concerns about food quality continue to increase. Mass spectrometry (MS) plays an indispensable role in food authentication and origin traceability. In this review, the applications of MS in food authentication and origin traceability by analyzing the main components and chemical fingerprints or profiles are summarized. In addition, the characteristic markers for food authentication are also reviewed, and the advantages and disadvantages of MS-based techniques for food authentication, as well as the current trends and challenges, are discussed. The fingerprinting and profiling methods, in combination with multivariate statistical analysis, are more suitable for the authentication of high-value foods, while characteristic marker-based methods are more suitable for adulteration detection. Several new techniques have been introduced to the field, such as proton transfer reaction mass spectrometry, ambient ionization mass spectrometry (AIMS), and ion mobility mass spectrometry, for the determination of food adulteration due to their fast and convenient analysis. As an important trend, the miniaturization of MS offers advantages, such as small and portable instrumentation and fast and nondestructive analysis. Moreover, many applications in food authentication are using AIMS, which can help food authentication in food inspection/field analysis. This review provides a reference and guide for food authentication and traceability based on MS.

Intravesical IR-780 instillation prevents radiation cystitis by protecting urothelial integrity.

PURPOSE: To explore an efficient preventive strategy for radiation cystitis. METHODS: We instilled IR-780 into the bladders of rats 1 h before bladder irradiation, and its bio-distribution was observed at different times. Bladders were then examined for pathogenic alterations and inflammation levels by day 3 and week 12 postirradiation, and the functional characteristics of the bladder were tested via cystometry by week 12. Human uroepithelial sv-huc-1 cells were used to determine the effect of IR-780 on cell viability, regardless of irradiation. We measured the intracellular levels of oxidative stress, DNA damage, apoptosis proportion, and the expression of antioxidant proteases and apoptotic caspases in IR-780 pretreated cells after radiation. RESULTS: IR-780 is localized in the urothelium after intravesical instillation in vivo. Ionizing radiation could induce acute impairment of the bladder urothelium and inflammation in the bladder on day 3. Fibrosis of the irradiated bladder progressed and eventually affected voiding function at 12 weeks. Treatment with IR-780 before irradiation ameliorated these changes. In vitro, IR-780 protected against cell viability and apoptosis of sv-huc-1 cells after irradiation. Additionally, IR-780 may assist in eliminating reactive oxygen species and repairing irradiation-induced DNA damage. CONCLUSION: Our data indicate that IR-780 can be used before irradiation to prevent acute urinary mucosal injury and late bladder dysfunction. Moreover, early urothelial impairment plays a significant role in radiation cystitis development.

Integrated transcriptomic and metabolomic analysis reveals the changes in monoterpene compounds during the development of Muscat Hamburg (Vitis vinifera L.) grape berries.

Monoterpenes are important compounds that influence the aromas of grapes and wines. The molecular mechanisms underlying the changes in monoterpenes during the grape ripening period have not been thoroughly characterized. In this study, the free and bound monoterpene profiles in Muscat Hamburg grape berries at different phenological stages were investigated at the transcriptomic and metabolomic levels. Principal component analyses indicated that the free and bound monoterpene profiles were affected by the developmental stages. Most monoterpenes were produced slowly before veraison, but they accumulated rapidly during the veraison period, after which their contents decreased slightly in mature berries. The transcriptomic analysis revealed 35 differentially expressed genes involved in the monoterpene synthesis pathway. The VIT_04s0008g04970, VIT_03s0063g02030 and VIT_15s0024g00850 expression levels were consistent with the changes in the accumulation of monoterpene compounds. The quantitative real-time polymerase chain reaction analysis of eight key differentially expressed genes in the monoterpenoid pathway confirmed the RNA-seq data were reliable. Our findings provide new insights into Muscat Hamburg grape aroma development. Further research on the period with the highest aroma potential may lead to enhanced grape berry aroma qualities.

Modified Qing'e Formula protects against UV-induced skin oxidative damage via the activation of Nrf2/ARE defensive pathway.

Exposure to ultraviolet (UV) light triggers the rapid generation and accumulation of reactive oxygen species (ROS) in skin cells, which increases oxidative stress damage and leads to photoaging. Nuclear factor E2-related factor 2 (Nrf2) modulates the antioxidant defense of skin cells against environmental factors, especially ultraviolet radiation. Natural products that target Nrf2-regulated antioxidant reactions are promising candidates for anti-photoaging. The aim of this study was to investigate the protective effect of Modified Qing'e Formula (MQEF) on UV-induced skin oxidative damage and its molecular mechanisms. In this study, the photoaging models of human keratinocytes (HaCaT) and ICR mice were established by UV irradiation. In vitro models showed that MQEF displayed potent antioxidant activity, significantly increased cell viability and reduced apoptosis and excess ROS levels. Meanwhile, the knockdown of Nrf2 reversed the antioxidant and anti-apoptotic effects of MQEF. In vivo experiments indicated that MQEF could protect the skin against UV-exposed injury which manifested by water loss, sensitivity, tanning, wrinkling, and breakage of collagen and elastic fibers. The application of MQEF effectively increased the activity of antioxidant enzymes and reduced the content of malondialdehyde (MDA) in mice. In addition, MQEF was able to activate Nrf2 nuclear translocation in mouse skin tissue. In summary, MQEF may attenuate UV-induced photoaging by upregulating Nrf2 expression and enhancing antioxidant damage capacity. MQEF may be a potential candidate to prevent UV-induced photoaging by restoring redox homeostasis.

Characterization and mechanism of aflatoxin degradation by a novel strain of Trichoderma reesei CGMCC3.5218.

Aflatoxins, which are produced mainly by Aspergillus flavus and A. parasiticus, are recognized as the most toxic mycotoxins, which are strongly carcinogenic and pose a serious threat to human and animal health. Therefore, strategies to degrade or eliminate aflatoxins in agro-products are urgently needed. We investigated 65 Trichoderma isolates belonging to 23 species for their aflatoxin B1 (AFB1)-degrading capabilities. Trichoderma reesei CGMCC3.5218 had the best performance, and degraded 100% of 50 ng/kg AFB1 within 3 days and 87.6% of 10 µg/kg AFB1 within 5 days in a liquid-medium system. CGMCC3.5218 degraded more than 85.0% of total aflatoxins (aflatoxin B1, B2, G1, and G2) at 108.2-2323.5 ng/kg in artificially and naturally contaminated peanut, maize, and feed within 7 days. Box-Behnken design and response surface methodology showed that the optimal degradation conditions for CGMCC3.5218 were pH 6.7 and 31.3°C for 5.1 days in liquid medium. Possible functional detoxification components were analyzed, indicating that the culture supernatant of CGMCC3.5218 could efficiently degrade AFB1 (500 ng/kg) with a ratio of 91.8%, compared with 19.5 and 8.9% by intracellular components and mycelial adsorption, respectively. The aflatoxin-degrading activity of the fermentation supernatant was sensitive to proteinase K and proteinase K plus sodium dodecyl sulfonate, but was stable at high temperatures, suggesting that thermostable enzymes or proteins in the fermentation supernatant played a major role in AFB1 degradation. Furthermore, toxicological experiments by a micronucleus assay in mouse bone marrow erythrocytes and by intraperitoneal injection and skin irritation tests in mice proved that the degradation products by CGMCC3.5218 were nontoxic. To the best of our knowledge, this is the first comprehensive study on Trichoderma aflatoxin detoxification, and the candidate strain T. reesei CGMCC3.5218 has high efficient and environment-friendly characteristics, and qualifies as a potential biological detoxifier for application in aflatoxin removal from contaminated feeds.

Distribution of Core Root Microbiota of Tibetan Hulless Barley along an Altitudinal and Geographical Gradient in the Tibetan Plateau.

The Tibetan Plateau is regarded as the third pole of the earth and is one of the least explored places on the planet. Tibetan hull-less barley (Hordeum vulgare L. var. nudum) is the only cereal crop grown widely in the Tibetan Plateau as a staple food. Extensive and long-term cropping of barley may influence the soil's chemical and biological properties, including microbial communities. However, microbiota associated with hull-less barley is largely unexplored. This study aimed to reveal the composition and diversity of bacterial and fungal communities associated with the hull-less barley at different elevations in the Tibetan Plateau. The core bacterial and fungal taxa of Tibetan hull-less barley were identified, with Bacillaceae, Blastocatellaceae, Comamonadaceae, Gemmatimonadaceae, Planococcaceae, Pyrinomonadaceae, Sphingomonadaceae, and Nitrospiraceae being the most abundant bacterial taxa and Ceratobasidiaceae, Chaetomiaceae, Cladosporiaceae, Didymellaceae, Entolomataceae, Microascaceae, Mortierellaceae, and Nectriaceae being the most abundant fungal taxa (relative abundance > 1%). Both bacterial and fungal diversities of hull-less barley were affected by altitude and soil properties such as total carbon, total nitrogen, and available phosphorus and potassium. Both bacterial and fungal diversities showed a significant negative correlation with altitude, indicating that the lower elevations provide a conducive environment for the survival and maintenance of hull-less barley-associated microbiota. Our results also suggest that the high altitude-specific microbial taxa may play an important role in the adaptation of the hull-less barley to the earth's third pole.

Discovery of the Relationship between Distribution and Aflatoxin Production Capacity of Aspergillusspecies and Soil Types in Peanut Planting Areas.

In order to study the relationship between the distribution and aflatoxin production capacity of Aspergillus species and soil types, 35 soil samples were collected from the main peanut planting areas in Xiangyang, which has 19.7 thousand square kilometers and is located in a special area with different soil types. The soil types of peanut planting areas in Xiangyang are mainly sandy loam and clay loam, and most of the soil is acidic, providing unique nature conditions for this study. The results showed that the Aspergillus sp. population in clay loam (9050 cfu/g) was significantly larger than that in sandy loam (3080 cfu/g). The percentage of atoxigenic Aspergillus strains isolated from sandy loam samples was higher than that from clay loam samples, reaching 58.5%. Meanwhile the proportion of high toxin-producing strains from clay loam (39.7%) was much higher than that from sandy loam (7.3%). Under suitable culture conditions, the average aflatoxin production capacity of Aspergillus isolates from clay loam samples (236.97 µg/L) was higher than that of strains from sandy loam samples (80.01 µg/L). The results inferred that under the same regional climate conditions, the density and aflatoxin production capacity of Aspergillus sp. in clay loam soil were significantly higher than that in sandy loam soil. Therefore, peanuts from these planting areas are at a relatively higher risk of contamination by Aspergillus sp. and aflatoxins.

Fungi population metabolomics and molecular network study reveal novel biomarkers for early detection of aflatoxigenic Aspergillus species.

Mycotoxins threaten global food safety, public health and cause huge socioeconomic losses. Early detection is an effective preventive strategy, yet efficient biomarkers for early detection of aflatoxigenic Aspergillus species are lacking. Here, we proposed to use untargeted metabolomics and machine learning to mine biomarkers of aflatoxigenic Aspergillus species. We systematically delineated metabolic differences across 568 extensive field sampling A. flavus and performed biomarker analysis. Versicolorin B, 11-hydroxy-O-methylsterigmatocystin et.al metabolites shown a high correlation (from 0.71 to 0.95) with strains aflatoxin-producing capacity. Molecular networking analysis deciphered the connection of aflatoxins and biomarkers as well as potential emerging mycotoxins. We then developed a model using the biomarkers as variables to discern aflatoxigenic Aspergillus species with 97.8% accuracy. A validation dataset and metabolome from other 16 fungal isolates confirmed the robustness and specificity of these biomarkers. We further demonstrated the solution feasibility in agricultural products by early detection of biomarkers, which predicted aflatoxin contamination risk 35-47 days in advance. A developed operable decision rule by the XGBoost algorithm help regulators to intuitively assess the risk prioritization with 87.2% accuracy. Our research provides novel insights into global food safety risk assessment which will be crucial for early prevention and control of mycotoxins.

Adulteration detection of essence in sesame oil based on headspace gas chromatography-ion mobility spectrometry.

Sesame oil is a traditional and delicious edible oil in China and Southeast Asia with a high price. However, sesame oil essence was often illegally added to cheaper edible oils to counterfeit sesame oil. In this study, a rapid and accurate headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) method was proposed to detect the counterfeit sesame oil where the other cheap oils were adulterated with essence. Combined with chemometric methods including principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA) and random forest (RF), authentic and counterfeit sesame oils adulterated with sesame essence (0.5%, w/w) were easily separated into two groups. More importantly, 2-methylbutanoic acid, 2-furfurylthiol, methylpyrazine, methional, and 2,5-dimethylpyrazine were found to be markers of sesame essence, which were used to directly identify the sesame essence. The determination of volatile compounds based on HS-GC-IMS was proven to be an effective method for adulteration detection of essence in sesame oil.

Transcriptomics Integrated with Metabolomics Reveals the Effect of Cluster Thinning on Monoterpene Biosynthesis in 'Muscat Hamburg' Grape.

Monoterpenes are crucial to floral and fruit aromas in grapes and wines. Cluster thinning is a common practice for improving grape quality. Using Vitis vinifera cv. Muscat Hamburg, the effects of three cluster-thinning regimes on the biosynthesis and accumulation of monoterpenes from véraison to harvest were investigated at the transcriptomics and targeted metabolomics levels. It was observed that more intense thinning produced higher concentrations of total monoterpenes, particularly in their bound forms. The numbers of differentially expressed genes among the three treatments were 193, 200, and 238 at the three developmental stages. In total, 10 modules were identified from a weighted gene correlation network analysis, and one module including 492 unigenes was associated with monoterpene metabolism. These findings provide new insights into the molecular basis of the relationship between cluster thinning and monoterpene biosynthesis in Muscat Hamburg grape. Cluster thinning could be carefully considered for its application in production.