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1.
Food Chem ; 368: 130849, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34419796

RESUMO

Umami intensity promotes food flavor blending and food choice, while a universal quantification procedure is still lacking. To evaluate perceived umami intensity (PUI) in seven categories of foods, modified two-alternative forced choice (2-AFC) method with monosodium glutamate as reference was applied. Meanwhile, we explored whether equivalent umami concentration (EUC) by chemical analysis and electronic tongue (E-tongue) are applicable in PUI quantification. The results indicated that EUC was appropriate in quantifying PUI of samples from meat, dairy, vegetable and mushroom groups (r = 1.00, p < 0.05). Moreover, models with a good prediction capacity for PUI and EUC (R2 > 0.99) were established in separated food categories by back propagation neural networks, where E-tongue data were set as input. This study explored the effectiveness of the three methods in evaluating the PUIs of various foods, which provides multiple choices for the food industry.

2.
Int J Parasitol ; 2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34543630

RESUMO

Honey bees (Apis) are important pollinators for food crops and wild plants, but are facing great threats from pathogens and parasites, especially an obligate ectoparasitic mite, Varroa destructor. Cell invasion is a key step for V. destructor to reproduce, and the parasite displays remarkable host preference in this process. Varroa destructor made its host-shift from its original host, the Asian honey bee Apis cerana, to the new host, the European honey bee Apis mellifera several decades ago. However, it remains largely unstudied whether V. destructor shows a cell invasion preference between the two host species. Using cell invasion bioassays on a modified four-well arena, we showed that V. destructor significantly preferred to invade the worker and drone larvae of A. mellifera rather than A. cerana, suggesting that the new host is much more attractive to the parasite than the original one. Using gas chromatography-mass spectrometry (GC-MS), we revealed significant differences between the cuticular hydrocarbon (CHC) profiles of worker and drone larvae of the two bee hosts. The amounts of methyl-branched alkanes and alkenes (unsaturated CHCs), but not n-alkanes, were significantly different, and A. mellifera worker and drone larvae were found to express significantly higher amounts of methyl-alkanes, while A. cerana larvae produced higher amounts of alkenes. Cell invasion bioassays with glass dummies showed that the mites preferred the glass dummies coated with the CHCs of A. mellifera worker or drone larvae, which indicates a role of larval CHCs in mediating the preferential cell invasion of Varroa. The findings from this study extend our understanding of the host preference of V. destructor, and can potentially contribute to the development of effective strategies for mite control.

3.
J Agric Food Chem ; 69(35): 10272-10280, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34436886

RESUMO

Salt is very important for human health and food seasoning. Recently, several peptides isolated from natural food products have been reported exhibiting a salty taste or a saltiness-enhancing function. In this investigation, taste-active peptides occurring in commercial Chinese fermented soybean curd were isolated and identified using ultrafiltration, gel permeation chromatography, ion-exchange chromatography, and nano-LC/Q-TOF MS/MS. The salty taste-enhancing function of the target fractions was confirmed by both a rat taste cell model and/or human sensory evaluation. Four decapeptides were found as taste-active compounds. Among them, peptide E (EDEGEQPRPF) was the most potent saltiness-enhancing peptide: 0.4 mg/mL in 50 mmol/L NaCl solution could increase its salty perception equivalent to the salt level of 63 mmol/L NaCl reference solution. The sequence of the peptide has been found in the α'-subunit of ß-conglycinin [Glycine max]. The remaining peptides V (VGPDDDEKSW), DD (DEDEQPRPIP), and DG (DEGEQPRPFP) showed umami and kokumi tastes as well as a weak saltiness-enhancing sensation. These findings suggest that the decapeptide EDEGEQPRPF could be a possible alternative to partially reduce the amount of sodium intake without compromising for saltiness.


Assuntos
Cloreto de Sódio , Alimentos de Soja , Animais , China , Peptídeos , Ratos , Alimentos de Soja/análise , Espectrometria de Massas em Tandem , Paladar
4.
Autoimmunity ; : 1-11, 2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34448644

RESUMO

Asthma is a common respiratory disease which is characterized by persistent airway inflammation. Abnormal expression of long non-coding RNAs (lncRNAs) is observed in asthma. However, whether lncRNA nuclear-enriched abundant transcript 1 (NEAT1) regulates asthmatic inflammation and its mechanism still needs to be further investigated. The expression levels of inflammatory factors (tumour necrosis factor (TNF)-α, interleukin (IL)-4, IL-13, and IL-10) were detected using reverse transcription quantitative real-time PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). MTT and flow cytometry assays were employed to determine cell proliferation and apoptosis, respectively. Dual luciferase reporter assay was performed to verify the relationship between miR-200a/b and MMP-16 or NEAT1. NEAT1 silencing markedly reduced TNF-α, IL-4, and IL-13 levels, while elevated IL-10 expression, suppressed cell proliferation, and promoted cell apoptosis. However, NEAT1 overexpression elicited the opposite effects on cell proliferation and inflammation cytokines secretion. What is more, NEAT1 negatively regulated miR-200a/b expression, and MMP16 was a target gene of miR-200a/b. miR-200a/b overexpression suppressed inflammation, cell proliferation, and enhanced cell apoptosis through regulation of MMP16. Moreover, MMP-16 overexpression or miR-200a/b inhibition abolished the regulatory effect of sh-NEAT1 on cell inflammation and apoptosis in BEAS-2B cells. NEAT1 acted as the role of sponge for miR-200a/b to regulate MMP-16 expression, thereby promoting asthma progression, suggesting that NEAT1 might have great potential as therapeutic target for asthma.

5.
J Food Biochem ; : e13840, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34189733

RESUMO

The volatile organic compounds (VOCs) in four Chinese freshwater fishes (i.e., Hypophthalmichthys molitrix (H), Aristichthys nobilis (A), Lateolabrax japonicus (L), Parabramis pekinensis (P)) were separated using gas chromatography-ion mobility spectrometry (GC-IMS) and ultrafast gas chromatography electronic-nose (uf-GC E-nose). Principal component analysis (PCA) was applied to distinguish the VOCs identified from the four freshwater fishes in both raw and cooked states. Twenty compounds were identified from the spectral database of GC-IMS, including five aldehydes, eight alcohols, six ketones, and three esters. In addition, using GC E-nose, 32 compounds were isolated by the first column MTX-5, and 24 compounds were isolated by the second column MXT-1701. PCA results showed that the four fishes could be well discriminated against. The odor profiles of raw and cooked fishes were clearly different. This study demonstrated that specific signals provided from GC-IMS could differentiate freshwater fishes. GC-IMS and uf-GC E-nose could be developed further to distinguish aquatic products based on VOCs. PRACTICAL APPLICATIONS: Two new methods, gas chromatography-ion mobility spectrometry (GC-IMS) and ultrafast gas chromatography electronic-nose (uf-GC E-nose), were used to analyze the volatile organic compounds (VOCs) in four Chinese freshwater fishes at raw and cooked status. GC-IMS has the characteristics of fast detection speed and high sensitivity. The accuracy of the qualitative analysis of the compounds is better with GC-IMS (larger data volume, leading to a better in-depth statistical analysis). Uf-GC E-nose could provide a nondestructive, fast, relatively low cost, and trustworthy way for flavor analysis. According to the techniques, the established fingerprints of VOCs provided an additional tool for food analysis.

6.
BMC Cancer ; 21(1): 677, 2021 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-34102999

RESUMO

BACKGROUND: Malignant melanoma of the female genital tract is relatively uncommon and accounts for 3-7% of all melanoma localizations. This study aimed to identify driver genes in melanoma of the female genital tract with the purpose of enhancing understanding of disease pathogenesis and identifying potential new therapeutic targets to develop effective therapies. METHODS: KIT (CD117) and BRAF expression were detected immunohistochemically. Polymerase Chain Reaction (PCR) and Sanger sequencing techniques were performed to identify the mutational status of BRAF, NRAS, KRAS, NF1, KIT, PDGFRA and SF3B1 on 19 melanomas of the female genital tract, paired with 25 cutaneous melanomas, 18 acral melanomas and 11 melanomas of nasal cavity. RESULTS: Somatic variant analysis identified KRAS (6/19; 32%) as the most commonly mutated gene, followed by KIT (4/19; 21%), SF3B1 (3/19; 16%) and NRAS (1/19; 5%). None of the cases were found to harbor BRAF, NF1 and PDGFRA mutations in melanomas of the female genital tract. However, none of the cases were found to harbor SF3B1 and KIT mutations in cutaneous melanomas, acral melanomas and melanomas of nasal cavity. Recurrent KIT mutations, as well as mutations in the less frequently mutated genes NRAS and SF3B1, were exclusively detected in vulvovaginal melanomas, but not in tumors arising in the cervix. However, recurrent KRAS mutations were detected in similar frequencies in tumors of the vulva, vagina, and cervix. Additionally, recurrent KRAS and KIT mutations occurred predominantly in polygonal and epithelioid cell types of melanoma in the female genital tract. Immunohistochemistry revealed moderate or strong cytoplasmic CD117 expression in 6 of the 19 cases (31.6%). CONCLUSIONS: We observed that gynecologic melanoma harbored distinct mutation rates in the KIT, BRAF, SF3B1, KRAS, and NRAS genes. Our findings support the notion that gynecologic melanoma is a distinct entity from non-gynecologic melanoma, and these findings offer insights into future therapeutic options for these patients.

7.
Scand J Psychol ; 62(4): 617-624, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34036581

RESUMO

Existing research has established that openness to experience can enhance dispositional awe. For the first time, the current study examines whether subjective socioeconomic status (SSES) moderates and a Zhong-Yong thinking style mediates this effect. A sample of 2,377 Chinese undergraduates (mean age 20.7, ranging from 18 to 26) was recruited. As shown in previous research, openness was found to be positively associated with dispositional awe. As predicted, the relationship was moderated by familial and school SSES. The positive correlation was significantly larger in cases of lower familial and school SSES. The mediating effect of Zhong-Yong thinking style was also supported in the relationship between openness and dispositional awe, as was the moderating effect of familial SSES; however, a suppressive effect was found for school SSES. The implications of this study are discussed herein.


Assuntos
Personalidade , Estudantes/psicologia , Adolescente , Adulto , China , Feminino , Humanos , Masculino , Classe Social , Estudantes/estatística & dados numéricos , Pensamento , Adulto Jovem
8.
Neoplasma ; 68(4): 892-898, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34034497

RESUMO

Survival rates are usually used to evaluate the effect of cancer treatment and prevention. No study has focused on the characteristic of population-based cancer survival in Fujian, which is regarded as one of the high-risk areas of cancer in China. This study aims to analyze the 5-year relative survival of patients in Fujian Province using population-based cancer registry data. A total of 8 population-based registries in Fujian Province reported cancer cases diagnosed in 2012-2014. Relative survival was calculated as the ratio between observed survival and expected survival. The 5-year relative survival for all cancers combined was 36.19% and the age-standardized 5-year relative survival for all patients was 31.80%. Females had higher relative survival than males (38.90% and 27.00%). The patients in urban areas had higher relative survival than those in rural areas (32.34% and 31.29%). Lung, gastric, liver, colorectal, and esophageal cancers were the five most common cancers, with 5-year relative survival below 50%. This is the first study that evaluated the population-based cancer relative survival in Fujian, China. Our study suggests that the overall survival of cancer patients in Fujian Province is poor. Furthermore, the results of this study can be used as a baseline for further research in Fujian, and provide important evidence for cancer etiology research.


Assuntos
Neoplasias Esofágicas , China/epidemiologia , Feminino , Humanos , Incidência , Masculino , Sistema de Registros , Taxa de Sobrevida
9.
J Virol Methods ; 293: 114163, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33864854

RESUMO

In terms of infectious diseases caused by a variety of microorganisms, the ability to promptly and accurately identify the causative agents is the first step on the path to all types of effective management of such infections. Among the various factors that are affecting global bee health, viruses have often been linked to honey bee colony losses and they pose a serious threat to the fraction of agriculture that depends on the service of pollinators. Over the past few decades, PCR-based molecular methods have provided powerful tools for rapid, specific, and sensitive detection and the quantification of difficult-to-grow pathogenic microorganisms such as viruses in honey bees. However, PCR-based methods require nucleic acid extraction and purification, which can be quite laborious and time-consuming and they involve the use of organic solvents and chaotropic agents like phenol and chloroform which are volatile and highly toxic. In response, we developed a novel and non-sacrificial method for detecting viral infections in honey bees. As little as 1 µl of hemolymph was collected from adult workers, larvae, and queens of bee colonies by puncturing the soft inter-tergal integument between the second and third dorsal tergum with a fine glass capillary. The hemolymph was then diluted and subjected to RT-PCR analysis directly. The puncture wound caused by the glass capillary was found to heal automatically and rapidly without any trouble and the lifespan of the experimental workers remained unaffected. Using this method, we detected multiple viruses including Deformed wing virus (DWV), Black queen cell virus (BQCV), and Sacbrood virus (SBV) in infected bees. Furthermore, expressed transcripts that indicate the induction of innate immune response to the virus infections were also detected in the hemolymph of infected bees. The simplicity and cost-effectiveness of this innovative approach will allow it to be a valuable, time-saving, safer, and more environmentally friendly contribution to bee disease management programs.

10.
Artigo em Inglês | MEDLINE | ID: mdl-33757290

RESUMO

Owing to co-epidemic of CRF01_AE and CRF07_BC in China, increasing numbers of the second-generation recombinants between them have been identified especially among sexual population. In this study, we identified a unique CRF01_AE/CRF07_BC recombinants from a male HIV-1 positive individual (18YA004) infected by heterosexual contact in Yan'an city, Shaanxi province. The near full-length genome analyses showed 18YA004 was divided into six fragments by five breakpoints located in the pol, vpr, vpu, and nef gene, respectively. Three CRF01_AE segments (segments I, III, and V) were all clustered within the cluster 4a lineage, exclusively circulating among MSM in the northern China. Coupled with our previous finding of CRF01_AE/C recombinant in Yan'an city, the emergence of CRF01_AE/CRF07_BC strain further suggested coexistence of multiple HIV-1 genotypes here. Therefore, it is necessary to continue monitoring the molecular epidemiology of HIV-1 among high-risk groups to obtain a better understanding of the genetic complexity and transmission of HIV-1 in this region.

11.
Microorganisms ; 9(3)2021 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-33673613

RESUMO

Nosema ceranae (Opisthosporidia: Microsporidia) is an emergent intracellular parasite of the European honey bee (Apis mellifera) and causes serious Nosema disease which has been associated with worldwide honey bee colony losses. The only registered treatment for Nosema disease is fumagillin-b, and this has raised concerns about resistance and off-target effects. Fumagillin-B is banned from use in honey bee colonies in many countries, particularly in Europe. As a result, there is an urgent need for new and effective therapeutic options to treat Nosema disease in honey bees. An RNA interference (RNAi)-based approach can be a potent strategy for controlling diseases in honey bees. We explored the therapeutic potential of silencing the sequences of two N. ceranae encoded spore wall protein (SWP) genes by means of the RNAi-based methodology. Our study revealed that the oral ingestion of dsRNAs corresponding to SWP8 and SWP12 used separately or in combination could lead to a significant reduction in spore load, improve immunity, and extend the lifespan of N. ceranae-infected bees. The results from the work completed here enhance our understanding of honey bee host responses to microsporidia infection and highlight that RNAi-based therapeutics are a promising treatment for honey bee diseases.

12.
Food Res Int ; 142: 110222, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33773696

RESUMO

Chinese dry-cured hams have unique aroma characteristics appreciated by local consumers. The volatile organic compounds (VOCs) of six selected Chinese dry-cured hams (Mianning, Nuodeng, Saba, Sanchuan, Wanhua, and Xuanen) were analyzed by solvent assisted flavor evaporation (SAFE) combined with GC × GC-ToF-MS and head-space (HS) injection combined with GC-IMS. To visualize VOCs and differentiate samples, principal component analysis (PCA) and multiple factor analysis (MFA) were performed. GC × GC-ToF-MS resulted in over five times more VOCs (265) than GC-IMS (45). However, PCA and MFA indicated similar results using GC-IMS or GC × GC-ToF-MS data, suggesting HS-GC-IMS as a good choice to differentiate dry-cured hams from different regions. Xuanen ham from Yunnan Province having smoky aroma was significantly different from other hams, likely due to its unique process. Many aldehydes (heptanal, nonanal, etc.) played an important role in Sanchuan ham. Ketones were related to other four dry-cured hams, though they came from different regions. This study provides valuable analytical data to characterize and discriminate the flavor profile of Chinese dry-cured hams.


Assuntos
Produtos da Carne , Carne de Porco , Compostos Orgânicos Voláteis , China , Cromatografia Gasosa-Espectrometria de Massas , Produtos da Carne/análise , Compostos Orgânicos Voláteis/análise
13.
PLoS Pathog ; 17(2): e1009270, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33600478

RESUMO

Nosemosis C, a Nosema disease caused by microsporidia parasite Nosema ceranae, is a significant disease burden of the European honey bee Apis mellifera which is one of the most economically important insect pollinators. Nevertheless, there is no effective treatment currently available for Nosema disease and the disease mechanisms underlying the pathological effects of N. ceranae infection in honey bees are poorly understood. Iron is an essential nutrient for growth and survival of hosts and pathogens alike. The iron tug-of-war between host and pathogen is a central battlefield at the host-pathogen interface which determines the outcome of an infection, however, has not been explored in honey bees. To fill the gap, we conducted a study to investigate the impact of N. ceranae infection on iron homeostasis in honey bees. The expression of transferrin, an iron binding and transporting protein that is one of the key players of iron homeostasis, in response to N. ceranae infection was analysed. Furthermore, the functional roles of transferrin in iron homeostasis and honey bee host immunity were characterized using an RNA interference (RNAi)-based method. The results showed that N. ceranae infection causes iron deficiency and upregulation of the A. mellifera transferrin (AmTsf) mRNA in honey bees, implying that higher expression of AmTsf allows N. ceranae to scavenge more iron from the host for its proliferation and survival. The suppressed expression levels of AmTsf via RNAi could lead to reduced N. ceranae transcription activity, alleviated iron loss, enhanced immunity, and improved survival of the infected bees. The intriguing multifunctionality of transferrin illustrated in this study is a significant contribution to the existing body of literature concerning iron homeostasis in insects. The uncovered functional role of transferrin on iron homeostasis, pathogen growth and honey bee's ability to mount immune responses may hold the key for the development of novel strategies to treat or prevent diseases in honey bees.


Assuntos
Abelhas/microbiologia , Interações Hospedeiro-Patógeno , Ferro/metabolismo , Microsporidiose/prevenção & controle , Nosema/fisiologia , Transferrinas/metabolismo , Animais , Microsporidiose/imunologia , Microsporidiose/metabolismo , Microsporidiose/microbiologia , Transferrinas/genética
14.
Food Res Int ; 137: 109669, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33233246

RESUMO

Blanched chicken, boiling the whole chicken without removing head and butt parts during process, is a traditional poultry product in China. In this manuscript, the flavor differences of five parts (skin, breast, thigh, head and butt) of the Chinese blanched chicken (CBC) were studied using sensory evaluation and instrumental analysis. Check-all-that-apply (CATA), rate-all-that-apply (RATA), and 9-point hedonic preference were used to collect consumers' sensory results. Gas chromatograph-time of flight mass spectrometer (GC-ToF-MS) and electronic nose (E-nose) were used to discriminate flavor variances. CATA perceptions showed different parts of CBC stimulated consumers' odor and emotion feelings differently. GC-ToF-MS and E-nose data elaborated that the flavor of breast with chicken-like flavor was better than the other parts. Consumers preferred the chicken breast part the most. This analysis of different parts of CBC could provide advice to cater consumers' preference and predict the quality change might induce.


Assuntos
Galinhas , Nariz Eletrônico , Animais , China , Odorantes , Paladar
15.
AIDS Res Hum Retroviruses ; 36(11): 952-956, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32746609

RESUMO

A wide variety of HIV-1 recombinants are constantly discovered in China. Comprehensively monitoring the genetic diversity of HIV-1 is very essential for understanding the molecular epidemiology and controlling the spread of the HIV-1 epidemic. In this study, we presented a novel HIV-1 unique CRF01_AE/C recombinant (19YA001) isolated from a female patient infected HIV-1 through heterosexual transmission in Yan'an city, Shaanxi province. The near full-length genome analyses showed 19YA001 was divided into two CRF01_AE and one C segments by two breakpoints observed in the vif/vpr region. To date, this is the first report revealing the characteristic of HIV-1 subtype in Yan'an city. And this unique recombinant strain might imply that the genetic diversity of HIV-1 in Yan'an city is complex. However, the sample size is too small. Further larger studies of HIV-1 molecular epidemiology are urgently needed to provide a better understanding of HIV-1 diversity and transmission in this region.

16.
Exp Lung Res ; 46(9): 321-331, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32820688

RESUMO

BACKGROUND: Asthma is one of the most frequent and serious diseases worldwide. Inflammation has been reported to correlate with airway remodeling, which is critical for the progression of asthma. Better understanding of novel molecules modulating asthma and the underlying mechanism will benefit explorations of new treatments. Method: To explore the role of miR-200a and miR-200b in asthma, miR-200a mimics/inhibitor and miR-200b mimics/inhibitor were employed in A549 cells, respectively. Expression levels of inflammatory cytokines, including TNF-α, IL-4, IL-5, IL-13 and IL-1ß, were measured by quantitative real time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). A dual luciferase reporter assay was performed to identify whether miR-200a/200b directly bound to Orosomucoid 1-like 3 (ORMDL3). ERK, p-ERK and MMP-9, involved in downstream pathways of ORMDL3, were detected using qRT-PCR and western blotting. Results: MiR-200a/200b silencing significantly increased the expression of inflammatory cytokines, including TNF-α, IL-4, IL-5, IL-13 and IL-1ß, in A549 cells. ORMDL3 was the target gene of miR-200a/200b, with high expression levels in miR-200a inhibitor and miR-200b inhibitor groups. MiR-200a and miR-200b played synergistic roles in the regulation of the inflammatory effect in A549 cells. Expression levels of p-ERK and MMP-9 were significantly increased in miR-200a inhibitor and miR-200b inhibitor groups and were rescued by ERK inhibitor and MMP-9 inhibitor, respectively. Conclusion: These findings suggest that miR-200a and miR-200b are required to regulate asthma inflammation. Reduction in miR-200a/200b promotes the development of asthma inflammation by targeting ORMDL3 to activate the ERK/MMP-9 pathway. Therefore, elevating miR-200a and miR-200b and decreasing ORMDL3 might be potential strategies for inhibition of the asthma process.

17.
J Phys Chem B ; 124(33): 7217-7228, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32786717

RESUMO

It is well understood that tetrahydrofuran (THF) molecules are able to stabilize the large cages (51264) of structure II to form the THF hydrate with empty small cages even at atmospheric pressure. This leaves the small cages to store gas molecules at relatively lower pressures and higher temperatures. The dissociation enthalpy and temperature strongly depend on the size of gas molecules enclathrated in the small cages of structure II THF hydrate. A high-pressure microdifferential scanning calorimeter was applied to measure the dissociation enthalpies and temperatures of THF hydrates pressurized by helium and methane under a constant pressure ranging from 0.10 to 35.00 MPa and a wide THF concentration ranging from 0.25 to 8.11 mol %. The dissociation temperature of binary He + THF and methane + THF hydrates increases along with an increase in the THF concentration in the liquid phase at a fixed pressure (e.g., 30 MPa), reaching a maximum value of 280.8 and 312.8 K, respectively, at stoichiometric concentration (5.56 mol % THF), and then remains nearly constant for even higher THF concentrations (>5.56 mol %). The effect of gas occupancy in the small cages on the dissociation enthalpy of He + THF and methane + THF mixed hydrates was further examined by using molecular dynamics (MD) simulations. The dissociation enthalpy of the He-THF mixed hydrates is independent of pressure with an average of 5.68 kJ/mol H2O over the pressure ranging from 0.10 to 30.0 MPa, consistent with the MD results of the He-THF mixed hydrates with low single occupancy (<23%) of helium molecules in the small cages. Consequently, the heat of adsorption of helium molecules in the small cages of the He-THF mixed hydrates is rather too weak to be identified. On the other hand, the dissociation enthalpy of the methane-THF hydrates increases from 9.11 to 10.01 kJ/mol H2O along with an increase in methane pressure over the pressure ranging from 5.0 to 30.0 MPa, consistent with the MD results of the methane-THF mixed hydrates with full occupancy of methane molecules in the small cages. These findings provide important information for the design of a potential medium of gas storage and transportation.

18.
Meat Sci ; 168: 108178, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32417671

RESUMO

A rapid method for analyzing of Jinhua ham samples in different aging time was created based on gas chromatography-ion mobility spectrometry (GC-IMS). The GC-IMS chromatograph provided information regarding the identities and intensities of 37 volatile flavor compounds, including both monomers and dimers. Principal component analysis (PCA) effectively distinguished the variation in the aroma of the Jinhua hams specific to aging time. Alcohol (octanol, 2-methylbutanol), ketones (2-butanone, 2-hexanone, 2-heptanone, acetoin, gamma-butyrolactone), aldehydes (butanal, 3-methylbutanal), ester (propyl acetate) and carboxylic acids (3-methylbutanoic acid) were considered as the main volatile compounds in the Jinhua ham samples. This GC-IMS method, then, proved to be feasible for the rapid and comprehensive detection of volatile compounds in Jinhua hams, and multivariance analysis (i.e.: PCA) was able to provide information related to aging time.


Assuntos
Produtos da Carne/análise , Compostos Orgânicos Voláteis/análise , Animais , Cromatografia Gasosa/métodos , Nariz Eletrônico , Manipulação de Alimentos/métodos , Espectrometria de Mobilidade Iônica/métodos , Odorantes/análise , Análise de Componente Principal , Suínos
19.
J Enzyme Inhib Med Chem ; 35(1): 897-905, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32216480

RESUMO

Lipopeptides have been reported to exhibit anti-obesity effects. In this study, we obtained a Bacillus velezensis strain FJAT-52631 that could coproduce iturins, fengycins, and surfactins. Results showed that the FJAT-52631 crude lipopeptide, purified fengycin, iturin, and surfactin standards exhibited strong inhibition activities against lipase with dose-dependence manners (half maximal inhibitory concentration (IC50) = 0.011, 0.005, 0.056, and 0.005 mg/mL, respectively). Moreover, fengycin and surfactin had the comparable activities with orlistat, but iturin not. It was revealed that the inhibition mechanism and type of the lipopeptides were reversible and competitive. The quenching mechanism of lipase was static and only one binding site between lipase and lipopoeptide was inferred from the fluorescence analysis. The docking analysis displayed that fengycin and surfactin could directly interact with the active amino acid residues (Ser or Asp) of lipase, but not with iturin. Our work suggests that the B. velezensis lipopeptides would have great potential to act as lipase inhibitors.


Assuntos
Inibidores Enzimáticos/farmacologia , Lipase/antagonistas & inibidores , Lipopeptídeos/farmacologia , Bacillus/química , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Lipase/metabolismo , Lipopeptídeos/química , Lipopeptídeos/isolamento & purificação , Simulação de Acoplamento Molecular , Estrutura Molecular , Mucor/enzimologia , Relação Estrutura-Atividade
20.
Artigo em Inglês | MEDLINE | ID: mdl-32028114

RESUMO

For the purpose of obtaining a more comprehensive flavor profile, volatile compounds in traditional Chinese dry-cured hams were studied by dual-fiber solid-phase microextraction (SPME) using two fibers simultaneously. By using the selected pair of fibers and under the optimal extraction time, there were total seventy-two volatile compounds identified, which was higher than the mono-fiber SPME method using a single fiber. Out of the seventy-two compounds, twenty-six compounds were not detected by using mono-fiber SPME and five among them are classified as the major aromatic compounds in the literatures. Due to the higher coverage and less tendency for the occurrence of competition among the volatiles, the total amount of volatiles extracted by dual-fiber SPME (510.02 ng/kg) was higher than mono-fiber SPME. Three grades of dry-cured hams were successfully distinguished based on dual-fiber SPME. The volatile compounds belonged to nine chemical families and differed in different grades of dry-cured hams. These results show that dual-fiber SPME is capable of analyzing flavor profiles more comprehensively and distinguishing traditional Chinese dry-cured hams.


Assuntos
Análise de Alimentos/métodos , Produtos da Carne/análise , Odorantes/análise , Carne de Porco/análise , Compostos Orgânicos Voláteis/química , Animais , Cromatografia Gasosa-Espectrometria de Massas , Microextração em Fase Sólida , Suínos
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