Articles de revues : « Tea triggered »

1

Chakraborty, B. N., M. Sharma, R. Das Biswas et A. N. Ghosh. « Pathogenesis-related proteins of tea triggered by Exobasidium vexans ». NBU Journal of Plant Sciences 3, n^o 1 (2009) : 59–66. http://dx.doi.org/10.55734/nbujps.2009.v03i01.011.

Texte intégral

Résumé :

The defense strategy of tea plants against Exobasidium vexans are multifold and include accumulation of pathogenesis-related (PR) proteins. A study on the association of defense enzymes with resistance in tea plants triggered by E. vexans revealed significant changes in the level of β-1.3-glucanase (PR 2) and chitinase (PR 3) exhibiting antimicrobial activity. Accumulation of defense proteins differed in time and magnitude. Time course studies points towards accumulation of PR-2 and PR-3 in the early hours, PR-9 later on and finally the antifungal metabolites that confer resistance to the plants. Treatment with salicylic acid (SA) stimulates a multicomponent defense response in tea leaves which was confirmed by immuno-localization of PR 2 and PR 3 in tea leaf tissues following induction of resistance. Induction of PR-3 in suspension-cultured tea cells following SA treatment was confirmed immunologically using antibody probes (PAb-chitnase). Subcellular localization of PR-3 and PR-2 in tea leaves were also confirmed by indirect immunogold labeling. Marked increase in frequency of gold particles following elicitation by SA treatment was evident. Cell defense responses associated with systemic acquired resistance induced by SA against E.vexans has been discussed in relation to the possible role of PR-proteins in immunizing tea plants.

Styles APA, Harvard, Vancouver, ISO, etc.

2

Chakraborty, B. N., M. Sharma, R. Das Biswas et A. N. Ghosh. « Pathogenesis-related proteins of tea triggered by Exobasidium vexans ». NBU Journal of Plant Sciences 3, n^o 1 (2009) : 59–66. http://dx.doi.org/10.55734/nbujps.2009.v03i01.011.

Texte intégral

Résumé :

The defense strategy of tea plants against Exobasidium vexans are multifold and include accumulation of pathogenesis-related (PR) proteins. A study on the association of defense enzymes with resistance in tea plants triggered by E. vexans revealed significant changes in the level of β-1.3-glucanase (PR 2) and chitinase (PR 3) exhibiting antimicrobial activity. Accumulation of defense proteins differed in time and magnitude. Time course studies points towards accumulation of PR-2 and PR-3 in the early hours, PR-9 later on and finally the antifungal metabolites that confer resistance to the plants. Treatment with salicylic acid (SA) stimulates a multicomponent defense response in tea leaves which was confirmed by immuno-localization of PR 2 and PR 3 in tea leaf tissues following induction of resistance. Induction of PR-3 in suspension-cultured tea cells following SA treatment was confirmed immunologically using antibody probes (PAb-chitnase). Subcellular localization of PR-3 and PR-2 in tea leaves were also confirmed by indirect immunogold labeling. Marked increase in frequency of gold particles following elicitation by SA treatment was evident. Cell defense responses associated with systemic acquired resistance induced by SA against E.vexans has been discussed in relation to the possible role of PR-proteins in immunizing tea plants.

Styles APA, Harvard, Vancouver, ISO, etc.

3

Qiu, Wen-Ze, Qi-Zhi Zhong, Yong Du, Yan Lv et Zhi-Kang Xu. « Enzyme-triggered coatings of tea catechins/chitosan for nanofiltration membranes with high performance ». Green Chemistry 18, n^o 23 (2016) : 6205–8. http://dx.doi.org/10.1039/c6gc02039a.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

4

Ding, Yiqian, Yu Wang, Chen Qiu, Wenjun Qian, Hui Xie et Zhaotang Ding. « Alternative splicing in tea plants was extensively triggered by drought, heat and their combined stresses ». PeerJ 8 (29 janvier 2020) : e8258. http://dx.doi.org/10.7717/peerj.8258.

Texte intégral

Résumé :

Drought and heat stresses can influence the expressions of genes, and thereby affect the growth and development of plants. Alternative splicing (AS) of genes plays crucial roles through increasing transcriptome diversity in plant stress responses. Tea plants, widely cultivated in the tropics and subtropics, are often simultaneously exposed to drought and heat stresses. In the present study, we performed a global transcriptome of tea leaves treated with drought, heat or their combination. In total, 19,019, 20,025 and 20,253 genes underwent AS in response to drought (DT), heat (HT) and their combined stress (HD), respectively, of which 12,178, 11,912 and 14,413 genes differentially spliced in response to DT, HT and HD, respectively. Also, 2,447 specific differentially spliced genes (DSGs) were found only in response to HD. All DSGs accounted for 48% of the annotated genes in tea tree genome. Comparison of DSGs and differentially expressive genes (DEGs) showed that the proportions of HT and HD-induced DSGs were 13.4% and 9.2%, while the proportion of DT increased to 28.1%. Moreover, the DEG-DSG overlapped genes tended to be enriched in a wide large of pathways in response to DT. The results indicated that the AS of genes in tea leaves was extensively triggered by drought, heat and their combined stresses. In addition, the AS enhanced the transcriptome adaption in response to drought and heat stresses, and the AS also provoked specific molecular functions in response to drought and heat synergy stress. The study might have practical significance for molecular genetic breeding of tea plants with stress resistance.

Styles APA, Harvard, Vancouver, ISO, etc.

5

Allocco, Jennifer Brianne, Christine McIntosh, Peter Wang, Michelle McKeague, Ying Wang, Alexandra Cassano, Stephen Z. Xie et al. « Variegated levels of alloreactive T cell dysfunction in transplantation tolerance determine graft vulnerability to infection-triggered rejection ». Journal of Immunology 210, n^o 1_Supplement (1 mai 2023) : 173.08. http://dx.doi.org/10.4049/jimmunol.210.supp.173.08.

Texte intégral

Résumé :

Abstract While advances have been made in therapies that achieve tolerance in mouse models of transplantation, successful tolerance remains vulnerable to inflammatory insults, which can trigger graft rejection. To identify strategies for improving the robustness of tolerance, we aim to better understand the mechanisms by which grafts are rejected after donor-specific tolerance is established. In a mouse model of cardiac allograft tolerance in which late infection with Listeria monocytogenes (Lm) can trigger graft rejection, we previously showed that host CD4 +T cells reactive to host MHC-II presenting a donor MHC-I-derived peptide (TCR75 cells) became intrinsically dysfunctional if the alloantigen persisted for 3 weeks or greater. Intriguingly, infection-dependent transplant rejection was not associated with transcriptional or functional reinvigoration of these cells. We hypothesized that there might be heterogeneity in the level of dysfunction of alloreactive T cells depending on duration of their cognate alloantigen persistence. Unlike TCR75 cells, CD4 +T cells specific for host MHC-II presenting a peptide derived from donor MHC Class II (TEa cells), a graft antigen that declines post-transplantation, retained functionality during tolerance induction. Consequently, TEa but not TCR75 cells expanded following Lm-infection, supporting a role for TEa-like cells in driving infection-triggered rejection. Prolonging T cell exposure to cognate alloantigens aggravated TEa dysfunction and rendered grafts resistant to Lm-dependent rejection. These findings demonstrate that inducing dysfunction in a broader array of allospecific T cells, by prolonging exposure to more alloantigens, lessens graft vulnerability to infections. Supported by the UChicago Growth Development and Disabilities Training Program (T32 HD007009). AHA predoctoral fellowships (20PRE35210946, 3PRE14550022 and 15PRE22180007). NIH T32-AI007090. UChicago Cardiovascular Pathophysiology and Biochemistry Training Grant (T32 HL07237). HHMI Med-into-Grad Program training grant (56006772). NIAID Grant P01AI-97113.

Styles APA, Harvard, Vancouver, ISO, etc.

6

Su, Xing, Wenyue Xie, Pudi Wang, Zhuoling Tian, Hao Wang, Zuoying Yuan, Xiaozhi Liu et Jianyong Huang. « Strong underwater adhesion of injectable hydrogels triggered by diffusion of small molecules ». Materials Horizons 8, n^o 8 (2021) : 2199–207. http://dx.doi.org/10.1039/d1mh00533b.

Texte intégral

Résumé :

We report a fully physically crosslinked injectable hydrogel composed of gelatin, tea polyphenols and urea, capable of realising smart adhesion to various materials, like glass and porcine skin, in diverse aqueous environments.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Shi, Jiale, Min Zhang, Liwen Gao, Qian Yang, Hazem M. Kalaji, Sheng Qiang, Reto Jörg Strasser et Shiguo Chen. « Tenuazonic Acid-Triggered Cell Death Is the Essential Prerequisite for Alternaria alternata (Fr.) Keissler to Infect Successfully Host Ageratina adenophora ». Cells 10, n^o 5 (25 avril 2021) : 1010. http://dx.doi.org/10.3390/cells10051010.

Texte intégral

Résumé :

The necrotrophic fungus Alternaria alternata contains different pathotypes that produce different mycotoxins. The pathotype Ageratina adenophora secretes the non-host-selective toxin tenuazonic acid (TeA), which can cause necrosis in many plants. Although TeA is thought to be a central virulence factor of the A. adenophora pathotype, the precise role of TeA in different stages of host infection by pathogens remains unclear. Here, an A. alternata wild-type and the toxin-deficient mutant ΔHP001 with a 75% reduction in TeA production were used. It was observed that wild-type pathogens could induce the reactive oxygen species (ROS) bursts in host leaves and killed photosynthetic cells before invading hyphae. The ROS interceptor catalase remarkably inhibited hyphal penetration and invasive hyphal growth and expansion in infected leaves and suppressed necrotic leaf lesion. This suggests that the production of ROS is critical for pathogen invasion and proliferation and disease symptom formation during infection. It was found that the mutant pathogens did not cause the formation of ROS and cell death in host leaves, showing an almost complete loss of disease susceptibility. In addition, the lack of TeA resulted in a significant reduction in the ability of the pathogen to penetrate invasive hyphal growth and spread. The addition of exogenous TeA, AAL-toxin, and bentazone to the mutant ΔHP001 pathogens during inoculation resulted in a significant restoration of pathogenicity by increasing the level of cell death, frequency of hyphal penetration, and extent of invasive hyphal spread. Our results suggest that cell death triggered by TeA is the essential requirement for successful colonization and disease development in host leaves during infection with A. adenophora pathogens.

Styles APA, Harvard, Vancouver, ISO, etc.

8

van Rossum, Huub H., et Daan van den Broek. « Ten-Month Evaluation of the Routine Application of Patient Moving Average for Real-Time Quality Control in a Hospital Setting ». Journal of Applied Laboratory Medicine 5, n^o 6 (12 juin 2020) : 1184–93. http://dx.doi.org/10.1093/jalm/jfaa071.

Texte intégral

Résumé :

Abstract Background In recent years there has been renewed interest in patient-based real-time quality control (PBRTQC) techniques. This interest has been stimulated by the availability of new optimization and validation methods. Only a limited amount of research has focused on investigating the true operational value of PBRTQC. Therefore, we have evaluated the performance and value of recently implemented patient moving average quality control (MA QC) procedures. Methods The MA QC settings and protocols were as previously described (Clin Chem Lab Med 2019;57:1329–38) and included MA QCs for 10 chemistry and 6 hematological tests, all performed on duplicate analyzer systems. All MA QC alarms that occurred during the first 10 months of routine clinical application were investigated for assay-specific alarm rate and occurrence in time. Furthermore, the causes of these MA QC alarms were investigated, and alarm relevance was determined on the basis of total allowable bias (TBa) and error (TEa) derived from biological variations. Results During the 10-month period, 202 individual MA QC alarms occurred, resulting in an overall MA QC alarm rate of 0.030% and a frequency of 4.67 per week. Most alarms were triggered by sodium MA QC. Based on all available fully executed and documented MA QC alarm work-ups, MA QC detected errors that in 26.0% of the alarms exceeded the TBa and in 13.7% the TEa. In 9.2% of the alarms, MA QC alarming triggered instant (technical) corrections. Conclusions Routine clinical application of MA QC is feasible with maintaining a manageable number of alarms and enabling detection of relevant analytical errors.

Styles APA, Harvard, Vancouver, ISO, etc.

9

Bai, Guoqiang, Shuanhong Ma, Runtian Qie, Zhiqing Liu, Yulin Shi, Cuihua Li, Rongjie Wang, Xuhong Guo, Feng Zhou et Xin Jia. « UV-Triggered Surface-Initiated Polymerization from Colorless Green Tea Polyphenol-Coated Surfaces ». Macromolecular Rapid Communications 37, n^o 15 (6 juin 2016) : 1256–61. http://dx.doi.org/10.1002/marc.201600065.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

10

Sawian, K. D., Amod Sharma et Sujay Kumar. « Marketing Pattern of Tea Enterprise in Meghalaya State : with Special Reference to White Tea Cultivation ». Ecology, Environment and Conservation 28 (2022) : 90–94. http://dx.doi.org/10.53550/eec.2022.v28i07s.015.

Texte intégral

Résumé :

The present research work was carried out to analyze the marketing pattern and post harvest management of tea enterprise with the help of primary data pertained to the year 2018-20 of tea enterprise in both district viz; Ri-Bhoi and West Garo hill. As it is well known fact and universally accepted concept that the organic agriculture has triggered a controversial debate in the past two decades; which is most important because it shed light on the darker sides of chemical-intensive conventional farming by offering an alternative due to the dumping off huge quantity of fertilizer and chemical used for enhancing the production and productivity to maximize the profit too. The data were collected from both the selected districts purposively due to the highest production and productivity as compared to the other districts of the Meghalaya state and a multi-stage simple random sampling technique was adopted due to the rationality sample plan of the respondents. Even the statistical frame-work and tabulation was adopted to fulfill the specific objectives of the study.

Styles APA, Harvard, Vancouver, ISO, etc.

11

Zaman, Shah, Jiazhi Shen, Shuangshuang Wang, Dapeng Song, Hui Wang, Shibo Ding, Xu Pang, Mengqi Wang, Yu Wang et Zhaotang Ding. « Effect of Shading on Physiological Attributes and Proteomic Analysis of Tea during Low Temperatures ». Plants 13, n^o 1 (24 décembre 2023) : 63. http://dx.doi.org/10.3390/plants13010063.

Texte intégral

Résumé :

Shading is an important technique to protect tea plantations under abiotic stresses. In this study, we analyzed the effect of shading (SD60% shade vs. SD0% no-shade) on the physiological attributes and proteomic analysis of tea leaves in November and December during low temperatures. The results revealed that shading protected the tea plants, including their soil plant analysis development (SPAD), photochemical efficiency (Fv/Fm), and nitrogen content (N), in November and December. The proteomics analysis of tea leaves was determined using tandem mass tags (TMT) technology and a total of 7263 proteins were accumulated. Further, statistical analysis and the fold change of significant proteins (FC < 0.67 and FC > 1.5 p < 0.05) revealed 14 DAPs, 11 increased and 3 decreased, in November (nCK_vs_nSD60), 20 DAPs, 7 increased and 13 decreased, in December (dCK_vs_dSD60), and 12 DAPs, 3 increased and 9 decreased, in both November and December (nCK_vs_nSD60). These differentially accumulated proteins (DAPs) were dehydrins (DHNs), late-embryogenesis abundant (LEA), thaumatin-like proteins (TLPs), glutathione S-transferase (GSTs), gibberellin-regulated proteins (GAs), proline-rich proteins (PRPs), cold and drought proteins (CORA-like), and early light-induced protein 1, which were found in the cytoplasm, nucleus, chloroplast, extra cell, and plasma membrane, and functioned in catalytic, cellular, stimulus-response, and metabolic pathways. In conclusion, the proliferation of key proteins was triggered by translation and posttranslational modifications, which might sustain membrane permeability in tea cellular compartments and could be responsible for tea protection under shading during low temperatures. This study aimed to investigate the impact of the conventional breeding technique (shading) and modern molecular technologies (proteomics) on tea plants, for the development and protection of new tea cultivars.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Wahyuni, Endang, Maryatun Maryatun, Nora Veri, Elly Susilawati, Lely Firrahmawati, Endah Wahyuni et Riyani Wulandari. « Green Tea Extract has a Protective Effect on Leptin and Lipid Profile Levels Due to the Induction of Depot Medroxyprogesterone Acetate ». Medical Archives 77, n^o 3 (2023) : 173. http://dx.doi.org/10.5455/medarh.2023.77.173-177.

Texte intégral

Résumé :

Background: Depot medroxyprogesterone acetate (DMPA) is a progesterone derivative synthesized in the laboratory. This substance has the ability to suppress ovulation, induce endometrial shrinkage, and even affect the hypothalamic-pituitary-gonadal axis in the reproductive system. Objective: The purpose of this study was to investigate the effects of administration of green tea extract on reducing visceral fat, increasing leptin levels, and improving the lipid profile in female rats injected with depot medroxyprogesterone acetate (DMPA). Results: This study was to look into the effects of green tea extract administration on visceral fat reduction, leptin levels, and lipid profile improvement as a result of DMPA administration. Analysis of HDL and LDL levels was performed by spectrophotometry. DMPA induced a significant increase in leptin levels compared with the control group (p 0.05). All doses of green tea extract can reduce this increase, with the highest doses reaching levels comparable to the control group (p > 0.05). DMPA significantly increased LDL levels compared to the control group (p < 0.05), and the highest green tea extract dose restored levels similar to the control group. DMPA triggered a decrease in HDL level that was significantly different from the control group (p < 0.05). The first dose of green tea extract can achieve HDL levels comparable to the control group (p > 0.05). Conclusion: It was concluded that green tea extract can protect the metabolic status through decreased leptin and an improvement of the lipid profile induced by DMPA.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Rojo, M. Ángeles, Manuel Garrosa, Pilar Jiménez, Tomás Girbés, Verónica Garcia-Recio, Manuel Cordoba-Diaz et Damián Cordoba-Diaz. « Unexpected Toxicity of Green Tea Polyphenols in Combination with the Sambucus RIL Ebulin ». Toxins 12, n^o 9 (22 août 2020) : 542. http://dx.doi.org/10.3390/toxins12090542.

Texte intégral

Résumé :

The safety of concentrated food complements intake is a major health concern. It has been well established that green tea polyphenols (GTPs) consumption promotes healthy effects. However, the ingestion of large amounts of GTPs is a matter of controversy due to reported adverse effects. We underwent a preliminary exploration of the effects of the oral administration of a standardized concentrated GTPs preparation on mice which suffered from reversible intestinal derangement promoted by sublethal amounts of the antiribosomal lectin ebulin f from dwarf elder (Sambucus ebulus L.). Neither independent oral administration of 30 mg/kg body weight Polyphenon 60 nor intraperitoneal administration of 2.5 mg/kg body weight ebulin f triggered lethal toxicity. In contrast, the simultaneous administration of these same doses of both Polyphenon 60 and ebulin f triggered an important and unexpected synergistic toxic action featured by the biphasic reduction of weight, which continued after eight days, reaching a reduction of 40%. Lethality appeared 2 days after the onset of the combined treatment and reached more than 50% after 10 days.

Styles APA, Harvard, Vancouver, ISO, etc.

14

Setiawan, Vendra, Sherlly Phangestu, Agatha Grace Soetikno, Angelina Arianti et Indrajati Kohar. « Rapid screening analysis of antioxidant activities in green tea products using DPPH and FRAP ». Pharmaceutical Journal of Indonesia 7, n^o 1 (1 décembre 2021) : 9–14. http://dx.doi.org/10.21776/ub.pji.2021.007.01.2.

Texte intégral

Résumé :

Free radicals are formed inside and outside the body. Free radicals inside the body can be created in the cell compartments. The reactions are complex through the initiation, propagation, and termination stages. On the other hand, free radicals in the outer body can be formed from pollutions and environmental damage action. Excessive free radicals cause oxidative stress and use destructive cellular to affect health conditions. Antioxidants are known as essential agents in biological systems against diseases triggered by free radicals. One of the many antioxidants found in tea plants (Camellia sinensis) is polyphenols. A colorimetry method was employed to evaluate the dominant antioxidant compound of the total phenolic and flavonoid content in two selected tea products. The total phenolic content was determined by utilizing the Folin-Ciocalteu reagent. In addition, an aluminum colorimetric assay is applied to assess flavonoid content. Rapid screening of antioxidant activity using a spectrophotometric method is employed to determine IC50 values of tea extracts utilizing DPPH and FRAP. The FRAP method showed more sensitivity in determining antioxidant activities with the feasibility of working in low analyte concentrations than the DPPH method. The high total phenolic and flavonoid contents found in this experiment are in line with low IC50 values. It was also found out that brewed green tea has lower total phenol content than green tea bags.

Styles APA, Harvard, Vancouver, ISO, etc.

15

Deana, Renzo, Loris Turetta, Massimo Donà, Anna Brunati, Lucia Michiel, Spiridione Garbisa et Arianna Donella-Deana. « Green tea epigallocatechin-3-gallate inhibits platelet signalling pathways triggered by both proteolytic and non-proteolytic agonists ». Thrombosis and Haemostasis 89, n^o 05 (2003) : 866–74. http://dx.doi.org/10.1055/s-0037-1613474.

Texte intégral

Résumé :

SummaryEpigallocatechin-3-gallate (EGCG), a component of green tea, inhibits human platelet aggregation and cytosolic [Ca2+]cincreases more strongly when these processes are induced by thrombin than by the non-proteolytic thrombin receptor activating peptide (TRAP), thromboxane mimetic U46619, or fluoroaluminate. In line with the previously demonstrated EGCG anti-proteolytic activity, a marked inhibition on aggregation is obtained by pre-incubation of thrombin with EGCG prior to addition to cellular suspension. The catechin also reduces cellular Ca2+ influx following thapsigargin-induced calcium emptying of endoplasmic reticulum, and the agonist-promoted cellular protein tyrosine phosphorylation. Both tyrosine kinases Syk and Lyn, immuno-precipitated from stimulated platelets, are greatly inhibited upon cellular pre-incubation with EGCG, which also inhibits the in vitro auto-phosphorylation and exogenous activity of these two enzymes purified from rat spleen. Both thrombin-induced aggregation and [Ca2+]c increase are reduced in platelets from rats that drank green tea solutions. It is concluded that EGCG inhibits platelet activation, by hindering the thrombin proteolytic activity, and by reducing the agonist-induced [Ca2+]cincrease through inhibition of Syk and Lyn activities.

Styles APA, Harvard, Vancouver, ISO, etc.

16

Fatmawati, Fatmawati, M. Athiah, S. Sinulingga, L. O. Oswari et Safyudin Safyudin. « PRODUCTION OF YELLOW WOOD ROOT TEA AS A BLOOD SUGAR STABILIZER ». Conferences of Medical Sciences Dies Natalis Faculty of Medicine Universitas Sriwijaya 3, n^o 1 (9 décembre 2021) : 117–22. http://dx.doi.org/10.32539/confmednatalisunsri.v3i1.78.

Texte intégral

Résumé :

Diabetes mellitus is a disease or metabolic disorder that is increasing year by year, characterized by high blood sugar levels as a result of insulin function insufficiency. Diabetes mellitus, which is often referred to as diabetes, is a disease or metabolic disorder that is increasing year by year, characterized by high blood sugar levels as a result of insulin function insufficiency. Treatment is by using drugs. Currently, a treatment using herbal medicine is being developed, one of which is Kayu kuning, where in previous studies it was found that the roots of Kayu kuning can reduce blood glucose levels. This has triggered the Biochemistry and Medical Chemistry section of the Faculty of Medicine to introduce to the public the preparations of this herbal medicine with ready-to-use packaging and the right dosage. The process of making tea is carried out at the Chemical Basic Medicine Laboratory, Faculty of Medicine, Sriwijaya University. About 5.6 kg of yellow wood root, washed and cut into small pieces then dried and ground to obtain a coarse powder (simplicia) of about 2.5 kg. Yellow wood root simplicia is put into tea bags weighing 10 g per bag. One tea bag can be brewed with 200 mL of hot water and drunk once a day. In this service, 250 tea bags were produced which were packaged in 50 packages (5 tea bags/package). The production of this yellow wood root tea has been carried out in the Komplek Azhar Lama, Kenten Laut, Palembang. Keywords: Herbal medicine, yellow root (Arcangelisia flava)

Styles APA, Harvard, Vancouver, ISO, etc.

17

Chen, Ziping, Huiping Li, Tianyuan Yang, Tingting Chen, Chunxia Dong, Quan Gu et Xunmin Cheng. « Transcriptome analysis provides insights into the molecular bases in response to different nitrogen forms-induced oxidative stress in tea plant roots (Camellia sinensis) ». Functional Plant Biology 47, n^o 12 (2020) : 1073. http://dx.doi.org/10.1071/fp20093.

Texte intégral

Résumé :

Previous studies have suggested that the maintenance of redox homeostasis is essential for plant growth. Here we investigated how redox homeostasis and signalling is modulated in response to different nitrogen (N) forms in tea plant roots. Our results showed that both N deficiency and nitrate (NO3–) can trigger the production of hydrogen peroxide and lipid peroxidation in roots. In contrast, these responses were not altered by NH4+. Further, N deficiency and NO3–-triggered redox imbalance was re-established by increased of proanthocyanidins (PAs) and glutathione (GSH), as well as upregulation of representative antioxidant enzyme activities and genes. To further explore the molecular bases of these responses, comparative transcriptome analysis was performed, and redox homeostasis-associated differentially expressed genes (DEGs) were selected for bioinformatics analysis. Most of these genes were involved in the flavonoid biosynthesis, GSH metabolism and the antioxidant system, which was specifically altered by N deficiency or NO3–. Moreover, the interplay between H2O2 (generated by RBOH and Ndufab1) and hormones (including abscisic acid, auxin, cytokinin and ethylene) in response to different N forms was suggested. Collectively, the above findings contribute to an understanding of the underlying molecular mechanisms of redox homeostasis and signalling in alleviating oxidative stress in tea plant roots.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Platonova, Nataliia, et Oksana Belous. « Biochemical Composition of Tea and its Changes under Different Factors ». Food Processing : Techniques and Technology 50, n^o 3 (12 octobre 2020) : 404–14. http://dx.doi.org/10.21603/2074-9414-2020-3-404-414.

Texte intégral

Résumé :

Introduction. The present research featured the antioxidant complex of Russian tea varieties. The research objective was to study the formation patterns of the components responsible for the quality characteristics of tea as a raw material and finished product. The paper describes the changes that the biochemical composition of tea undergoes during the growing season and during processing. The study focused on pigments, vitamins, caffeine, and amino acids. Study objects and methods. The research featured the following varieties of tea grown in the Krasnodar region of Russia: “Kolkhida” (control) and “Sochi”; forms – No. 582, 3823, 855, and 2264. The research was performed on the foundation plantation of collection tea in the village of Uch-Dere (Lazarevsky district of Sochi, Krasnodar region, Russia) and in the laboratory of plant physiology and biochemistry. The study involved traditional and advanced research methods. Results and discussion. The paper introduces some results of a comprehensive analysis of the biochemical composition of various tea sorts. Shoots No. 2264, 3823, and the “Sochi” variety demonstrated high values of ascorbic acid. Form No. 3823 and the “Sochi” variety proved to have a relatively stable content of ascorbic acid. All experimental plants had the highest caffeine synthesis in July (from 24.633 to 28.614 μg/100 g). Processing destroyed caffeine and reduced its amount. The experimental samples of raw materials had eleven amino acids, the largest number being synthesized in May. Processing triggered both general changes in their quantity and varietal differences in the metabolic reactions of amino acid conversion. Conclusion. The tea flushes and finished products differed in all biologically active substances, which is associated with both varietal characteristics and the effect of weather conditions during vegetation.

Styles APA, Harvard, Vancouver, ISO, etc.

19

Tian, Zuo Xi. « High Voltage Triggered Spark Gap with Repeatable Gas Filling Structure ». Applied Mechanics and Materials 432 (septembre 2013) : 373–77. http://dx.doi.org/10.4028/www.scientific.net/amm.432.373.

Texte intégral

Résumé :

To resolve the problems of short working life and narrow operating voltage range of the spark gap with one-offin gas filling structure, a spark gap with repeatable gas filling structure was designed. The spark gap was composed of three electrodes and two gaps as well as gas filling devices. Electrodes structures adopted the form of field aberration three-electrode gas spark switch forming two discharge gaps between three electrodes of anode, cathode and triggering electrode. Gas filling devices were composed of fast connector, gas pipe, barometer and air valve, by which the gaps could be repeatedly charged and deflated from a hole at the center of anode. Working life is lengthened by exchanging gas, and operating voltage range is widened by changing gas pressure in a certain range. The spark gap was manufactured and applied successfully in a TEA CO2 laser with pulse energy 170J. The results prove the designs feasible.

Styles APA, Harvard, Vancouver, ISO, etc.

20

Yin, Jianli, Linfeng Yang, Lisha Mou, Kaili Dong, Jian Jiang, Shuai Xue, Ying Xu, Xinyi Wang, Ying Lu et Haifeng Ye. « A green tea–triggered genetic control system for treating diabetes in mice and monkeys ». Science Translational Medicine 11, n^o 515 (23 octobre 2019) : eaav8826. http://dx.doi.org/10.1126/scitranslmed.aav8826.

Texte intégral

Résumé :

Cell-based therapies are recognized as the next frontier in medicine, but the translation of many promising technologies into the clinic is currently limited by a lack of remote-control inducers that are safe and can be tightly regulated. Here, we developed therapeutically active engineered cells regulated by a control system that is responsive to protocatechuic acid (PCA), a metabolite found in green tea. We constructed multiple genetic control technologies that could toggle a PCA-responsive ON/OFF switch based on a transcriptional repressor from Streptomyces coelicolor. We demonstrated that PCA-controlled switches can be used for guide RNA expression–mediated control of the CRISPR-Cas9 systems for gene editing and epigenetic remodeling. We showed how these technologies could be used as implantable biocomputers in live mice to perform complex logic computations that integrated signals from multiple food metabolites. Last, we used our system to treat type 1 and type 2 diabetes in mice and cynomolgus monkeys. This biocompatible and versatile food phenolic acid–controlled transgenic device opens opportunities for dynamic interventions in gene- and cell-based precision medicine.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Faustin, Jennifer, Neni Susilaningsih, Muflihatul Muniroh, Bahrudin Bahrudin, Endang Mahati et Hermawan Istiadi. « Effect of white tea (Camellia sinensis) leaf extract on cigarette smoke and high-fat diet-induced atherosclerosis in Wistar rats ». Journal of Advanced Biotechnology and Experimental Therapeutics 6, n^o 3 (2023) : 552. http://dx.doi.org/10.5455/jabet.2023.d148.

Texte intégral

Résumé :

Atherosclerosis is a complex pathological process begins with endothelial dysfunction, one of which is triggered by an inflammatory process due to increased levels of low-density lipoprotein (LDL) cholesterol and exposure to cigarette smoke. White tea leaf (Camellia sinensis) shows an anti-inflammatory effect which has not been known for its effect on the atherosclerotic process. The aim of this study is to determine the effect of Camellia sinensis leaf extract on IL-6 levels, foam cell count, and the ratio of intima-media thickness of cigarette smoke and high-fat diet-induced atherosclerosis in Wistar rats. Thirty male Wistar rats were randomly divided into 5 groups namely HC (healthy control), NC (negative control), WT100, WT200, and WT400 (treated with white tea leaf extract 100, 200, and 400 mg/kgBW/day, respectively). IL-6 levels were measured by the ELISA method. At 400x microscope magnification, foam cell count and intima-media thickness ratio were seen in aortic tissue. Administration of graded doses of white tea leaf extract in groups WT100, WT200, WT400 significantly reduced IL-6 levels, foam cell count, and intima-media thickness ratio of abdominal aorta compared to the NC group. These results suggest that white tea leaf extract may decrease levels of IL-6, foam cell count, and intima-media thickness ratio in atherosclerosis-induced Wistar rats.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Qi, Guoyuan, Yashi Mi, Rong Fan, Runnan Li, Yiwen Wang, Xingyu Li, Shuxian Huang et Xuebo Liu. « Tea polyphenols ameliorate hydrogen peroxide- and constant darkness-triggered oxidative stress via modulating the Keap1/Nrf2 transcriptional signaling pathway in HepG2 cells and mice liver ». RSC Advances 7, n^o 51 (2017) : 32198–208. http://dx.doi.org/10.1039/c7ra05000c.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

23

Bond et Derbyshire. « Tea Compounds and the Gut Microbiome : Findings from Trials and Mechanistic Studies ». Nutrients 11, n^o 10 (3 octobre 2019) : 2364. http://dx.doi.org/10.3390/nu11102364.

Texte intégral

Résumé :

In recent years, the gut microbiome has become a focal point of interest with growing recognition that a well-balanced gut microbiota composition is highly relevant to an individual's health status and well-being. Its profile can be modulated by a number of dietary factors, although few publications have focused on the effects of what we drink. The present review performed a systematic review of trials and mechanistic studies examining the effects of tea consumption, its associated compounds and their effects on the gut microbiome. Registered articles were searched up to 10th September 2019, in the PubMed and Cochrane library databases along with references of original articles. Human trials were graded using the Jadad scale to assess quality. Altogether 24 publications were included in the main review—six were human trials and 18 mechanistic studies. Of these, the largest body of evidence related to green tea with up to 1000 mL daily (4–5 cups) reported to increase proportions of Bifidobacterium. Mechanistic studies also show promise suggesting that black, oolong, Pu-erh and Fuzhuan teas (microbially fermented ‘dark tea’) can modulate microbial diversity and the ratio of Firmicutes to Bacteroidetes. These findings appear to support the hypothesis that tea ingestion could favourably regulate the profile of the gut microbiome and help to offset dysbiosis triggered by obesity or high-fat diets. Further well-designed human trials are now required to build on provisional findings.

Styles APA, Harvard, Vancouver, ISO, etc.

24

Chiedozie Onyejiaka Ibegbulem, Chidi Uzoma Igwe et Shirley James Demason. « Consumption of green tea infusion causes loss of nutrients through faeces in Wistar rats ». GSC Biological and Pharmaceutical Sciences 26, n^o 1 (30 janvier 2024) : 220–26. http://dx.doi.org/10.30574/gscbps.2024.26.1.0541.

Texte intégral

Résumé :

Relationship between consumption of green tea infusion and faecal nutrient content was studied. Twelve male Wistar rats (aged 10 to 12 weeks and weighed 87 to 120 g) were divided into two groups of six rats each. The control group was placed on tap water, while the test group was placed on green tea infusion (0.20 g/50 ml) daily as the only source of fluid; for 28 days. Both groups consumed rat feed ad libitum. Phytochemicals detected in the infusion were tannins, saponins, alkaloids, flavonoids and phytosterols. The infusion increased test animals’ appetite for food (% coefficient of variation, % CV = 5.44) but decreased their appetite for the infusion (% CV = 72.41). Animals placed on the infusion (test group) did not gain more weight (% CV = 3.86) nor had better feed conversion ratio (% CV = 1.41). Faecal ash and fibre contents were not affected by tea consumption (% CV = 3.38 and 2.03, respectively). Control rats lost more carbohydrate and moisture (% CV = 27.58 and 9.58, respectively) but test rats lost more protein and lipids. Energy lost by test rats through faecal matter was not appreciably higher (101.31 vs 96.24 kcal/ 100 g sample; % CV = 2.56). Loss of certain nutrients in the test rats may have been triggered by the inhibitory action of polyphenols such as tannins present in the infusion on their digestive enzymes. In conclusion, the tea infusion elicited increased feacal excretion of proteins and lipids in treated animals.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Gao, Chenxi, Yue Sun, Jing Li, Zhe Zhou, Xuming Deng, Zhihui Wang, Shaoling Wu et al. « High Light Intensity Triggered Abscisic Acid Biosynthesis Mediates Anthocyanin Accumulation in Young Leaves of Tea Plant (Camellia sinensis) ». Antioxidants 12, n^o 2 (6 février 2023) : 392. http://dx.doi.org/10.3390/antiox12020392.

Texte intégral

Résumé :

There is increasing interest in the production and consumption of tea (Camellia sinensis L.) processed from purple–leaved cultivar due to their high anthocyanin content and health benefits. However, how and why seasonal changes affect anthocyanin accumulation in young tea leaves still remains obscured. In this study, anthocyanin and abscisic acid (ABA) contents in young leaves of Zifuxing 1 (ZFX1), a cultivar with new shoots turning to purple in Wuyi Mountain, a key tea production region in China, were monitored over four seasons. Young leaves produced in September were highly purplish, which was accompanied with higher anthocyanin and ABA contents. Among the environmental factors, the light intensity in particular was closely correlated with anthocyanin and ABA contents. A shade experiment also indicated that anthocyanin content significantly decreased after 168 h growth under 75% shade, but ABA treatment under the shade conditions sustained anthocyanin content. To confirm the involvement of ABA in the modulation of anthocyanin accumulation, anthocyanin, carotenoids, chlorophyll, ABA, jasmonic acid (JA), and salicylic acid (SA) in the young leaves of four cultivars, including ZFX1, Zijuan (ZJ), wherein leaves are completely purple, Rougui (RG) and Fudingdabaicha (FDDB) wherein leaves are green, were analyzed, and antioxidant activities of the leaf extracts were tested. Results showed that ABA, not other tested hormones, was significantly correlated with anthocyanin accumulation in the purple–leaved cultivars. Cultivars with higher anthocyanin contents exhibited higher antioxidant activities. Subsequently, ZFX1 plants were grown under full sun and treated with ABA and fluridone (Flu), an ABA inhibitor. ABA treatment elevated anthocyanin level but decreased chlorophyll contents. The reverse was true to those treated with Flu. To pursue a better understanding of ABA involvement in anthocyanin accumulation, RNA–Seq was used to analyze transcript differences among ABA– or Flu–treated and untreated ZFX1 plants. Results indicated that the differentially expressed genes in ABA or Flu treatment were mainly ABA signal sensing and metabolism–related genes, anthocyanin accumulation-related genes, light–responsive genes, and key regulatory MYB transcription factors. Taking all the results into account, a model for anthocyanin accumulation in ZFX1 cultivar was proposed: high light intensity caused reactive oxygen stress, which triggered the biosynthesis of ABA; ABA interactions with transcription factors, such as MYB-enhanced anthocyanin biosynthesis limited chlorophyll and carotenoid accumulation; and transport of anthocyanin to vacuoles resulting in the young leaves of ZFX1 with purplish coloration. Further research is warranted to test this model.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Chen, Xiaoqiang, Yuefei Wang, Yalin Wu, Baoyu Han, Yuejin Zhu, Xiaolin Tang et Qinglei Sun. « Green tea polysaccharide-conjugates protect human umbilical vein endothelial cells against impairments triggered by high glucose ». International Journal of Biological Macromolecules 49, n^o 1 (juillet 2011) : 50–54. http://dx.doi.org/10.1016/j.ijbiomac.2011.03.008.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

27

Qileng, Aori, Tao Liu, Jiancong Wang, Tongyue Yin, Haoran Shen, Liang He, Weipeng Liu et Yingju Liu. « Self-triggered fluorescent metal-organic framework mimic enzyme for competitive immunoassay of hypoglycemic drug in functional tea ». Colloids and Surfaces B : Biointerfaces 215 (juillet 2022) : 112527. http://dx.doi.org/10.1016/j.colsurfb.2022.112527.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

28

More, Yogesh, Sachin Padghan, Rajesh Bhosale, Rajendra Pawar, Avinash Puyad, Sidhanath Bhosale et Sheshanath Bhosale. « Proton Triggered Colorimetric and Fluorescence Response of a Novel Quinoxaline Compromising a Donor-Acceptor System ». Sensors 18, n^o 10 (12 octobre 2018) : 3433. http://dx.doi.org/10.3390/s18103433.

Texte intégral

Résumé :

Quinoxaline-based novel acid-responsive probe Q1 was designed on the basis of a conjugated donor-acceptor (D-A) subunit. Q1 shows colorimetric and fluorometric changes through protonation and deprotonation in dichloromethane. With the addition of the trifluoroacetic acid (TFA), UV-vis absorption spectral changes in peak intensity of Q1 was observed. Moreover, the appearance of a new peaks at 284 nm 434 nm in absorption spectra with the addition of TFA indicating protonation of quinoxaline nitrogen and form Q1.H+ and Q1.2H+. The emission spectra display appearance of new emission peak at 515 nm. The optical property variations were supported by time resolved fluorescence studies. The energy band gap was calculated by employing cyclic voltammetry and density functional calculations. Upon addition of triethylamine (TEA) the fluorescence emission spectral changes of Q1 are found to be reversible. Q1 shows color changes from blue to green in basic and acidic medium, respectively. The paper strip test was developed for making Q1 a colorimetric and fluorometric indicator.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Liu, Po-Len, Jung-Tung Liu, Hsuan-Fu Kuo, Inn-Wen Chong et Chong-Chao Hsieh. « Epigallocatechin Gallate Attenuates Proliferation and Oxidative Stress in Human Vascular Smooth Muscle Cells Induced by Interleukin-1βvia Heme Oxygenase-1 ». Mediators of Inflammation 2014 (2014) : 1–8. http://dx.doi.org/10.1155/2014/523684.

Texte intégral

Résumé :

Proliferation of vascular smooth muscle cells (VSMCs) triggered by inflammatory stimuli and oxidative stress contributes importantly to atherogenesis. The association of green tea consumption with cardiovascular protection has been well documented in epidemiological observations, however, the underlying mechanisms remain unclear. This study aimed to elucidate the effects of the most active green tea catechin derivative, (−)-epigallocatechin-3-gallate (EGCG), in human aortic smooth muscle cells (HASMCs), focusing particularly on the role of a potent anti-inflammatory and antioxidative enzyme heme oxygenase-1 (HO-1). We found that pretreatment of EGCG dose- and time-dependently induced HO-1 protein levels in HASMCs. EGCG inhibited interleukin- (IL-)1β-induced HASMC proliferation and oxidative stress in a dose-dependent manner. The HO-1 inducer CoPPIX decreased IL-1β-induced cell proliferation, whereas the HO-1 enzyme inhibitor ZnPPIX significantly reversed EGCG-caused growth inhibition in IL-1β-treated HASMCs. At the molecular level, EGCG treatment significantly activated nuclear factor erythroid-2-related factor (Nrf2) transcription activities. These results suggest that EGCG might serve as a complementary and alternative medicine in the treatment of these pathologies by inducing HO-1 expression and subsequently decreasing VSMC proliferation.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Kang, Jian, John R. Huguenard et David A. Prince. « Voltage-Gated Potassium Channels Activated During Action Potentials in Layer V Neocortical Pyramidal Neurons ». Journal of Neurophysiology 83, n^o 1 (1 janvier 2000) : 70–80. http://dx.doi.org/10.1152/jn.2000.83.1.70.

Texte intégral

Résumé :

To investigate voltage-gated potassium channels underlying action potentials (APs), we simultaneously recorded neuronal APs and single K+ channel activities, using dual patch-clamp recordings (1 whole cell and 1 cell-attached patch) in single-layer V neocortical pyramidal neurons of rat brain slices. A fast voltage-gated K+ channel with a conductance of 37 pS (Kf) opened briefly during AP repolarization. Activation of Kf channels also was triggered by patch depolarization and did not require Ca2+influx. Activation threshold was about −20 mV and inactivation was voltage dependent. Mean duration of channel activities after single APs was 6.1 ± 0.6 ms (mean ± SD) at resting membrane potential (−64 mV), 6.7 ± 0.7 ms at −54 mV, and 62 ± 15 ms at −24 mV. The activation and inactivation properties suggest that Kf channels function mainly in AP repolarization but not in regulation of firing. Kf channels were sensitive to a low concentration of tetraethylammonium (TEA, 1 mM) but not to charybdotoxin (ChTX, 100 nM). Activities of A-type channels (KA) also were observed during AP repolarization. KA channels were activated by depolarization with a threshold near −45 mV, suggesting that KA channels function in both repolarization and timing of APs. Inactivation was voltage dependent with decay time constants of 32 ± 6 ms at −64 mV (rest), 112 ± 28 ms at −54 mV, and 367 ± 34 ms at −24 mV. KA channels were localized in clusters and were characterized by steady-state inactivation, multiple subconductance states (36 and 19 pS), and inhibition by 5 mM 4-aminopyridine (4-AP) but not by 1 mM TEA. A delayed rectifier K+ channel (Kdr) with a unique conductance of 17 pS was recorded from cell-attached patches with TEA/4-AP-filled pipettes. Kdrchannels were activated by depolarization with a threshold near −25 mV and showed delayed long-lasting activation. Kdr channels were not activated by single action potentials. Large conductance Ca2+-activated K+ (BK) channels were not triggered by neuronal action potentials in normal slices and only opened as neuronal responses deteriorated (e.g., smaller or absent spikes) and in a spike-independent manner. This study provides direct evidence for different roles of various K+ channels during action potentials in layer V neocortical pyramidal neurons. Kf and KA channels contribute to AP repolarization, while KA channels also regulate repetitive firing. Kdr channels also may function in regulating repetitive firing, whereas BK channels appear to be activated only in pathological conditions.

Styles APA, Harvard, Vancouver, ISO, etc.

31

Yan, Fei, Dong Qu, Xiaohua Chen, Jianjun Yang, Haitao Zeng et Xinsheng Li. « Transcriptome Analysis of 5-Aminolevulinic Acid Contributing to Cold Tolerance in Tea Leaves (Camellia sinensis L.) ». Forests 14, n^o 2 (20 janvier 2023) : 198. http://dx.doi.org/10.3390/f14020198.

Texte intégral

Résumé :

Tea (Camellia sinensis L.) is an important perennial cash crop and a typical subtropical plant. It is widely concerned because of its unique flavor and health benefits. In recent years, low temperatures have severely restricted the growth of tea plants and quality of tea products, especially in spring. As a common precursor for all porphyrin compounds, 5-aminolevulinic acid (ALA) is involved in photosynthesis and respiration and plays an active role in improving salt, drought and low-temperature tolerance in plants. However, it is not yet clear what affect exogenous ALA has on tea plants’ tolerance under low temperature. In the present study, we collected and deciphered the transcriptome profiles from Shaancha No. 1 leaf tissues under low temperature (−4 °C) treatment (T-4), exogenous ALA application (T-A), pretreated ALA before low temperature (T-A-4) and untreated control (T-CK). Results showed that 4990 (2375 up- and 2615 down-regulated), 223 (103 up- and 120 down-regulated) and 92 (13 up- and 79 down-regulated) differentially expression genes (DEGs) were identified at T-CK vs. T-4, T-CK vs. T-A and T-4 vs. T-A-4, respectively. Both T-4 and T-A treatments triggered a myriad of stress resistance genes up-regulated related to multiple signaling pathways by means of Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. This included MAPK, a toll-like receptor that signals pathways involved in cold resistance. However, gene ontology (GO) analysis showed that the DEGs in T-4 treatment were mainly enriched in the phenylpropanoid metabolic and redox processes that were relevant to membrane structure damage response. In contrast, the DEGs in T-A treatment were mainly enriched in cell recognition and amylase activity. Furthermore, in pairwise comparison of T-A-4 vs. T-4, the DEGs were enriched in ascorbate and aldarate, retionol, taurine and hypotaurine, glutathione metabolic pathways and two biosynthesis process including zeatin, diterpenoid biosynthesis, which might contribute to mitigating the damage caused by low temperature. Overall, these results indicated that exogenous ALA application may improve the biochemical attributes and enhance the tolerance to low temperature, which provides a valuable strategy to improve tea quality and cold stress.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Segal, M., et J. L. Barker. « Rat hippocampal neurons in culture : Ca2+ and Ca2+-dependent K+ conductances ». Journal of Neurophysiology 55, n^o 4 (1 avril 1986) : 751–66. http://dx.doi.org/10.1152/jn.1986.55.4.751.

Texte intégral

Résumé :

Rat hippocampal neurons grown in dissociated cell culture were studied in a medium containing 1 microM tetrodotoxin (TTX) and 25 mM tetraethylammonium (TEA), which eliminated the Na+ and K+ conductances normally activated by depolarizing current injections. In this medium depolarizing current pulses evoked depolarizing regenerative potentials and afterhyperpolarizations in most cells. Both of these events were blocked by close application of Co2+ or Cd2+. These events resemble Ca2+ spikes reported previously in hippocampal pyramidal cells. The membrane potential at which these Ca2+ spikes could be triggered and the rheobase current necessary were dependent on the potential at which the cell was conditioned: the more depolarized the holding potential, the more negative the absolute potential at which a spike could be triggered and the less rheobase current required. The duration of these Ca2+ spikes was also sensitive to the holding potential: the more depolarized the holding level, the longer the duration of the triggered spikes. The amplitude and duration of the Ca2+ spikes were enhanced in a reversible manner by 0.5-1.0 mM 4-aminopyridine (4-AP) delivered in the vicinity of the cell. Two-electrode voltage-clamp analysis of cells studied in TTX, TEA-containing medium revealed an inward current response that peaked in 25-50 ms during depolarizing commands. This response first became detectable during commands to -30 mV. It peaked in amplitude during commands to -10 mV and was enhanced in medium containing elevated [Ca2+]0. It was blocked by either 20 mM Mg2+, 0.2 mM Cd2+, 5 mM Co2+, or 5 mM Mn2+. These results have led us to identify this inward current response as ICa2+. 4-AP enhanced the magnitude and duration of ICa2+ independent of the drug's depressant effects on a transient K+ current also observed under these same experimental conditions. In many but not all cells the Ca2+ spike was followed by a long-lasting hyperpolarization associated with an increase in membrane conductance. This was blocked by Co2+. Under voltage clamp ICa2+ was followed by a slowly developing outward current response that was attenuated by Co2+ or Cd2+. These properties observed under current- and voltage-clamp recording conditions are superficially similar to those previously reported for Ca2+-dependent K+ conductance mechanisms (IC) recorded in these and other membranes. Long-lasting tail currents following activation of IC inverted in the membrane potential range for the K+ equilibrium potential found in these cells.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Dong, Zhiqiang, Yiyi Lin, Shibo Xu, Linna Chang, Xingjun Zhao, Xifan Mei et Xiuqiu Gao. « NIR-triggered tea polyphenol-modified gold nanoparticles-loaded hydrogel treats periodontitis by inhibiting bacteria and inducing bone regeneration ». Materials & ; Design 225 (janvier 2023) : 111487. http://dx.doi.org/10.1016/j.matdes.2022.111487.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

34

S. Ridad, Geraldine, Rolinne Marie B. Besite, Joy Jireh E. Marba et Ryl Mae J. Mercado. « Effectiveness of Tea Tree (Melaleuca alternifolia) Essential Oil and Jojoba Carrier Oil through Topical Application on the Relief of Allergies Caused by Aeroallergens ». International Journal of Advancement in Life Sciences Research 07, n^o 01 (2024) : 65–72. http://dx.doi.org/10.31632/ijalsr.2024.v07i01.007.

Texte intégral

Résumé :

Background: Allergies are one of the most common chronic conditions worldwide. Due to the cost and possible side effects of pharmacologic treatments, aromatherapy, an alternative method in relieving allergies was studied. Objective: This study aimed to determine the effectiveness of Jojoba Oil and 100% Tea Tree Essential Oil combination through topical application as an alternative method for relieving severity and frequency of allergic symptoms triggered by aeroallergens. Methods: A pre-experimental one-group pre-test and post-test research design was used to determine whether the combination of Tea Tree and Jojoba Oil produced an effect to the respondents’ allergic signs and symptoms. A modified 3-part questionnaire was used to gather data from thirty (30) purposively selected college students. Results: It appeared that the combination oil when applied topically resulted to a reduction in the severity and frequency of the allergic symptoms; specifically watery eyes, nasal congestion, runny nose, nasal itching, sneezing, coughing, chest tightness, wheezing, shortness of breath and phlegm production. The observed alleviation of symptoms is deemed significant with P-values less than 0.05, except for the reduction in the frequency of wheezing (P-value=.101>0.05) and shortness of breath (P-value=.053>0.05) nonetheless. Conclusion: Hence, the combination oil composed of Tea Tree essential oil with 2% dilution and Jojoba carrier oil when applied topically to the hot spots of the body reduces allergic symptoms. Nurses and other public healthcare providers can consider aromatherapy in the treatment regimen of individuals who have allergies but prefers to manage it non-pharmacologically or does not have access to anti-allergy medications.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Kimura, Kayoko, Dusan Palic et James Roth. « Effect of green tea extract and epigallocatechin gallate on bovine neutrophil function (140.10) ». Journal of Immunology 184, n^o 1_Supplement (1 avril 2010) : 140.10. http://dx.doi.org/10.4049/jimmunol.184.supp.140.10.

Texte intégral

Résumé :

Abstract Neutrophils play an important role as the first line of defense in protecting hosts from microbial invasion, but the delayed migration and prolonged presence of neutrophils can result in sustained inflammation. The aim of this study was to determine effect of green tea extract (GT) and its major anti-inflammatory component, epigallocatechin gallate (EG), on bovine neutrophils in order to decipher possible clinical use of GT and EG to alleviate inflammation. Effects of GT and EG on degranulation, oxidative burst, CD11b expression, and neutrophil apoptosis were investigated at concentrations from 1 to 100 μg/mL (GT) or μM (EG) in different assay conditions. Concurrent, pre, and post treatment of GT and EG with saline or standard stimulant (calcium ionophore or phorbol myristate acetate) significantly reduced degranulation and superoxide production compared to control (no GT/EG). Significant reduction in CD11b expression was observed in EG treated samples, but not all GT samples had similar effect. GT and EG at concentrations of 50 and 100 μg/mL (GT) or μM (EG) triggered neutrophil apoptosis determined by Annex-V cell surface binding and 7 amino-actinoycin intracellular staining. The in vitro reduction of cattle neutrophil function suggests potential of GT and EG to be used in clinical applications as support to anti-inflammatory therapy.

Styles APA, Harvard, Vancouver, ISO, etc.

36

Ma, Yi-Xiao, Xiao-Han Wu, Hui-Shi Wu, Zhan-Bo Dong, Jian-Hui Ye, Xin-Qiang Zheng, Yue-Rong Liang et Jianliang Lu. « Different Catabolism Pathways Triggered by Various Methylxanthines in Caffeine-Tolerant Bacterium Pseudomonas putida CT25 Isolated from Tea Garden Soil ». Journal of Microbiology and Biotechnology 28, n^o 7 (28 juillet 2018) : 1147–55. http://dx.doi.org/10.4014/jmb.1801.01043.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

37

Yeste, Marc, Marc Llavanera, Guillermo Pérez, Fabiana Scornik, Josep Puig-Parri, Ramon Brugada, Sergi Bonet et Elisabeth Pinart. « Elucidating the Role of K+ Channels during In Vitro Capacitation of Boar Spermatozoa : Do SLO1 Channels Play a Crucial Role ? » International Journal of Molecular Sciences 20, n^o 24 (15 décembre 2019) : 6330. http://dx.doi.org/10.3390/ijms20246330.

Texte intégral

Résumé :

This study sought to identify and localize SLO1 channels in boar spermatozoa by immunoblotting and immunofluorescence, and to determine their physiological role during in vitro sperm capacitation. Sperm samples from 14 boars were incubated in a capacitation medium for 300 min in the presence of paxilline (PAX), a specific SLO1-channel blocker, added either at 0 min or after 240 min of incubation. Negative controls were incubated in capacitation medium, and positive controls in capacitation medium plus tetraethyl ammonium (TEA), a general K+-channel blocker, also added at 0 min or after 240 min of incubation. In all samples, acrosome exocytosis was triggered with progesterone after 240 min of incubation. Sperm motility and kinematics, integrity of plasma and acrosome membranes, membrane lipid disorder, intracellular calcium levels and acrosin activity were evaluated after 0, 60, 120, 180, 240, 250, 270 and 300 min of incubation. In boar spermatozoa, SLO1 channels were found to have 80 kDa and be localized in the anterior postacrosomal region and the mid and principal piece of the tail; their specific blockage through PAX resulted in altered calcium levels and acrosome exocytosis. As expected, TEA blocker impaired in vitro sperm capacitation, by altering sperm motility and kinematics and calcium levels. In conclusion, SLO1 channels are crucial for the acrosome exocytosis induced by progesterone in in vitro capacitated boar spermatozoa.

Styles APA, Harvard, Vancouver, ISO, etc.

38

Wang, Dongxu, Yijun Wang, Xiaochun Wan, Chung S. Yang et Jinsong Zhang. « Green tea polyphenol (−)-epigallocatechin-3-gallate triggered hepatotoxicity in mice : Responses of major antioxidant enzymes and the Nrf2 rescue pathway ». Toxicology and Applied Pharmacology 283, n^o 1 (février 2015) : 65–74. http://dx.doi.org/10.1016/j.taap.2014.12.018.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

39

Bhattacharya, Udayan, Babli Halder, Sibabrata Mukhopadhyay et Ashok K. Giri. « Role of oxidation-triggered activation of JNK and p38 MAPK in black tea polyphenols induced apoptotic death of A375 cells ». Cancer Science 100, n^o 10 (octobre 2009) : 1971–78. http://dx.doi.org/10.1111/j.1349-7006.2009.01251.x.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

40

Pezzato, Elga, Luigi Sartor, Isabella Dell'Aica, Ruggero Dittadi, Massimo Gion, Claudio Belluco, Mario Lise et Spiridione Garbisa. « Prostate carcinoma and green tea : PSA-triggered basement membrane degradation and MMP-2 activation are inhibited by (?)epigallocatechin-3-gallate ». International Journal of Cancer 112, n^o 5 (2004) : 787–92. http://dx.doi.org/10.1002/ijc.20460.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

41

Sartor, Luigi, Elga Pezzato, Massimo Donà, Isabella Dell'Aica, Fiorella Calabrese, Monica Morini, Adriana Albini et Spiridione Garbisa. « Prostate carcinoma and green tea : (−)epigallocatechin-3-gallate inhibits inflammation-triggered MMP-2 activation and invasion in murine TRAMP model ». International Journal of Cancer 112, n^o 5 (30 juillet 2004) : 823–29. http://dx.doi.org/10.1002/ijc.20496.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

42

Dielis, ArneW J. H., Henri M. H. Spronk, Rene van Oerle, Karly Hamulyak, Martin H. Prins, Hugo ten Cate et Arina J. ten Cate-Hoek. « Thrombin generation in patients after acute deep-vein thrombosis ». Thrombosis and Haemostasis 100, n^o 08 (2008) : 240–45. http://dx.doi.org/10.1160/th08-02-0099.

Texte intégral

Résumé :

SummaryThrombin generation measurement may be of value for assessing the risk of venous thromboembolism, but its long term profile has not been assessed in patients. We evaluated thrombin generation by Calibrated Automated Thrombogram (CAT) in plasma during follow up of 104 consecutive patients after an acute episode of deep venous thrombosis. Blood was drawn three times over the course of 24 months. Thrombin generation was measured in absence and presence of thrombomodulin and compared to a reference range derived from thrombin generation curves in 137 healthy volunteers. Thrombin generation of patients showed significantly higher endogenous thrombin potential (ETP) and peak height compared to the reference population. Differences were more pronounced in assays triggered with I pM TF. Inhibition by thrombomodulin was attenuated in patients off anticoagulants as compared to the reference population (21 % vs.42.2%, p<0.0001); inhibition in patients on anticoagulant treatment was less pronounced (9.7%, p<0.000l). Protein C activity, protein S antigen as well as free protein S showed highly negative correlation with ETP in all patients. A significant negative relation was found between FVIII levels and thrombomodulin induced reduction of ETP and peak height. In conclusion, thrombin generation by CAT reflects changes in coagulation status in patients following athromboembolic event and is most sensitive at CAT analysis triggered with I pM TEA role for factor VIII as an important attributable cause of hypercoagulability is reflected by the reduced inhibitory effect of thrombomodulin at high factor VIII levels.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Tsukamoto, Shuntaro, Keisuke Hirotsu, Motofumi Kumazoe, Yoko Goto, Kaori Sugihara, Takafumi Suda, Yukari Tsurudome et al. « Green tea polyphenol EGCG induces lipid-raft clustering and apoptotic cell death by activating protein kinase Cδ and acid sphingomyelinase through a 67 kDa laminin receptor in multiple myeloma cells ». Biochemical Journal 443, n^o 2 (27 mars 2012) : 525–34. http://dx.doi.org/10.1042/bj20111837.

Texte intégral

Résumé :

EGCG [(−)-epigallocatechin-3-O-gallate], the major polyphenol of green tea, has cancer chemopreventive and chemotherapeutic activities. EGCG selectively inhibits cell growth and induces apoptosis in cancer cells without adversely affecting normal cells; however, the underlying molecular mechanism in vivo is unclear. In the present study, we show that EGCG-induced apoptotic activity is attributed to a lipid-raft clustering mediated through 67LR (67 kDa laminin receptor) that is significantly elevated in MM (multiple myeloma) cells relative to normal peripheral blood mononuclear cells, and that aSMase (acid sphingomyelinase) is critical for the lipid-raft clustering and the apoptotic cell death induced by EGCG. We also found that EGCG induces aSMase translocation to the plasma membrane and PKCδ (protein kinase Cδ) phosphorylation at Ser664, which was necessary for aSMase/ceramide signalling via 67LR. Additionally, orally administered EGCG activated PKCδ and aSMase in a murine MM xenograft model. These results elucidate a novel cell-death pathway triggered by EGCG for the specific killing of MM cells.

Styles APA, Harvard, Vancouver, ISO, etc.

44

McIntosh, Christine, Michelle Miller, Ying Wang, Luqiu Chen, Zheng Jenny Zhang, Jiao-Jing Wang, Jennifer Allocco, Anita S. F. Chong et Maria-Luisa Alegre. « Mechanisms of transplant rejection after the establishment of donor-specific tolerance ». Journal of Immunology 204, n^o 1_Supplement (1 mai 2020) : 161.22. http://dx.doi.org/10.4049/jimmunol.204.supp.161.22.

Texte intégral

Résumé :

Abstract Patients weaned from immunosuppressive drugs can reject their graft after years of stability, often after an infection. We have modeled this in mice: infection with Listeria monocytogenes (Lm) at the maintenance phase of tolerance can precipitate rejection of a cardiac allograft. Here, we investigated which alloreactive Tconvs may mediate rejection after Lm infection. To track the function of allospecific Tconvs, we seeded tracer TCR75 cells, which recognize I-Ab-restricted donor Kd peptide, into B6 mice prior to Balb/c cardiac transplantation with or without tolerance induction by anti-CD154 + Balb/c splenocytes. ≥35 days post-transplantation, TCR75 cells persisting in tolerant mice developed a PD-1hi CD127lo exhausted-like phenotype and expressed the anergy markers FR4 and CD73. TCR75 cells were dysfunctional, exhibiting 10-fold less recall expansion compared to memory cells and lacked IFNγ and TNF production upon re-stimulation. Intriguingly, TCR75 cells in tolerant hosts remained dysfunctional after Lm infection, suggesting that they may not participate in infection-triggered rejection. Having found that programming T cell dysfunction in tolerance required persistence of the allograft for ~3 weeks, we tested whether T cells specific for alloantigens expressed transiently after transplantation, such as donor MHC Class II, remain functional during tolerance and may mediate rejection after Lm infection. We used tracer TEa cells specific for a donor Class II Eα peptide presented on I-Ab. During tolerance, TEa cells remained PD-1lo and CD73lo, and retained recall expansion and TNF production. We conclude that functional allospecific Tconvs present during tolerance may pose a previously unappreciated risk to the graft.

Styles APA, Harvard, Vancouver, ISO, etc.

45

Li, Xiaoyue, Zewen Liu, Ting Gao, Wei Liu, Keli Yang, Rui Guo, Chang Li et al. « Tea Polyphenols Protects Tracheal Epithelial Tight Junctions in Lung during Actinobacillus pleuropneumoniae Infection via Suppressing TLR-4/MAPK/PKC-MLCK Signaling ». International Journal of Molecular Sciences 24, n^o 14 (24 juillet 2023) : 11842. http://dx.doi.org/10.3390/ijms241411842.

Texte intégral

Résumé :

Actinobacillus pleuropneumoniae (APP) is the causative pathogen of porcine pleuropneumonia, a highly contagious respiratory disease in the pig industry. The increasingly severe antimicrobial resistance in APP urgently requires novel antibacterial alternatives for the treatment of APP infection. In this study, we investigated the effect of tea polyphenols (TP) against APP. MIC and MBC of TP showed significant inhibitory effects on bacteria growth and caused cellular damage to APP. Furthermore, TP decreased adherent activity of APP to the newborn pig tracheal epithelial cells (NPTr) and the destruction of the tight adherence junction proteins β-catenin and occludin. Moreover, TP improved the survival rate of APP infected mice but also attenuated the release of the inflammation-related cytokines IL-6, IL-8, and TNF-α. TP inhibited activation of the TLR/MAPK/PKC-MLCK signaling for down-regulated TLR-2, TLR4, p-JNK, p-p38, p-PKC-α, and MLCK in cells triggered by APP. Collectively, our data suggest that TP represents a promising therapeutic agent in the treatment of APP infection.

Styles APA, Harvard, Vancouver, ISO, etc.

46

Fernández-Fernández, José M., Muriel Nobles, Aoife Currid, Esther Vázquez et Miguel A. Valverde. « Maxi K+ channel mediates regulatory volume decrease response in a human bronchial epithelial cell line ». American Journal of Physiology-Cell Physiology 283, n^o 6 (1 décembre 2002) : C1705—C1714. http://dx.doi.org/10.1152/ajpcell.00245.2002.

Texte intégral

Résumé :

The cell regulatory volume decrease (RVD) response triggered by hypotonic solutions is mainly achieved by the coordinated activity of Cl− and K+ channels. We now describe the molecular nature of the K+ channels involved in the RVD response of the human bronchial epithelial (HBE) cell line 16HBE14o−. These cells, under isotonic conditions, present a K+current consistent with the activity of maxi K+ channels, confirmed by RT-PCR and Western blot. Single-channel and whole cell maxi K+ currents were readily and reversibly activated following the exposure of HBE cells to a 28% hypotonic solution. Both maxi K+ current activation and RVD response showed calcium dependency, inhibition by TEA, Ba2+, iberiotoxin, and the cationic channel blocker Gd3+ but were insensitive to clofilium, clotrimazole, and apamin. The presence of the recently cloned swelling-activated, Gd3+-sensitive cation channels (TRPV4, also known as OTRPC4, TRP12, or VR-OAC) was detected by RT-PCR in HBE cells. This channel, TRPV4, which senses changes in volume, might provide the pathway for Ca2+ influx under hypotonic solutions and, consequently, for the activation of maxi K+channels.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Cattaert, D., A. Araque, W. Buno et F. Clarac. « MOTOR NEURONES OF THE CRAYFISH WALKING SYSTEM POSSESS TEA+-REVEALED REGENERATIVE ELECTRICAL PROPERTIES ». Journal of Experimental Biology 188, n^o 1 (1 mars 1994) : 339–45. http://dx.doi.org/10.1242/jeb.188.1.339.

Texte intégral

Résumé :

In crustaceans, some motor neurones (MNs) have been shown to be part of the central pattern generator in the stomatogastric system (Harris-Warrick et al. 1992; Moulins, 1990), the swimmeret system (Heitler, 1978) or the walking system (Chrachri and Clarac, 1990). These MNs induce changes in the central rhythm when depolarized and are conditional oscillators in the stomatogastric ganglion. Moreover, in the walking system, rhythmic activity can be triggered by muscarinic cholinergic agonists (Chrachri and Clarac, 1987). We have recently analyzed the role of muscarinic receptors in crayfish walking leg MNs (D. Cattaert and A. Araque, in preparation) and demonstrated that oxotremorine, a muscarinic agonist, evoked long-lasting depolarizing responses associated with an increased input resistance. The outward current blocked by oxotremorine is likely to be carried by K+, as is the case for the M current (IM) in vertebrates (Brown and Adams, 1980). In most neurones, K+ conductances play a principal role in maintaining the membrane potential at rest: for example, IM is active at the resting membrane potential, thus contributing to its maintenance, and the 'delayed-rectifier' (IK) assists the fast repolarization after an action potential. Some K+ conductances are Ca2+-dependent (IK,Ca) and are activated by an increase in internal Ca2+ concentration. In such cases, Ca2+ currents may result in hyperpolarization of the neurone through activation of IK,Ca. In opposition to these K+ currents, the direct effect of Na+ and Ca2+ conductances is to depolarize the neurone. For example, the persistant Na+ current (INap) that is responsible for the slow subthreshold depolarization termed slow pre-potentials (Gestrelius et al. 1983; Leung and Yim, 1991) participates in the formation of pacemaker depolarization (Barrio et al. 1991) and generates plateau-type responses in control conditions (Barrio et al. 1991; Llinas and Sugimori, 1980). Similarly Ca2+ or non-specific (Na+/Ca2+) conductances generate such events in Aplysia californica burster neurones (Adams and Benson, 1985), crustacean cardiac ganglion (Tazaki and Cooke, 1990), insect neurones (Hancox and Pitman, 1991) and crustacean stomatogastric ganglion (Kiehn and Harris-Warrick, 1992). Since crustacean MNs can participate in rhythm production, such depolarizing conductances may exist in most of them and may contribute to the long-lasting MN depolarizations and spike bursts present during locomotion.

Styles APA, Harvard, Vancouver, ISO, etc.

48

Suzuki, Masahiko, Leonardo Albarracin, Yuji Tsujikawa, Kohtaro Fukuyama, Iwao Sakane, Julio Villena et Haruki Kitazawa. « Lactiplantibacillus plantarum LOC1 Isolated from Fresh Tea Leaves Modulates Macrophage Response to TLR4 Activation ». Foods 11, n^o 20 (18 octobre 2022) : 3257. http://dx.doi.org/10.3390/foods11203257.

Texte intégral

Résumé :

Previously, we demonstrated that Lactiplantibacillus plantarum LOC1, originally isolated from fresh tea leaves, was able to improve epithelial barrier integrity in in vitro models, suggesting that this strain is an interesting probiotic candidate. In this work, we aimed to continue characterizing the potential probiotic properties of the LOC1 strain, focusing on its immunomodulatory properties in the context of innate immunity triggered by Toll-like receptor 4 (TLR4) activation. These studies were complemented by comparative and functional genomics analysis to characterize the bacterial genes involved in the immunomodulatory capacity. We carried out a transcriptomic study to evaluate the effect of L. plantarum LOC1 on the response of murine macrophages (RAW264.7 cells) to the activation of TLR4. We demonstrated that L. plantarum LOC1 exerts a modulatory effect on lipopolysaccharide (LPS)-induced inflammation, resulting in a differential regulation of immune factor expression in macrophages. The LOC1 strain markedly reduced the LPS-induced expression of some inflammatory cytokines (IL-1β, IL-12, and CSF2) and chemokines (CCL17, CCL28, CXCL3, CXCL13, CXCL1, and CX3CL1), while it significantly increased the expression of other cytokines (TNF-α, IL-6, IL-18, IFN-β, IFN-γ, and CSF3), chemokines (IL-15 and CXCL9), and activation markers (H2-k1, H2-M3, CD80, and CD86) in RAW macrophages. Our results show that L. plantarum LOC1 would enhance the intrinsic functions of macrophages, promoting their protective effects mediated by the stimulation of the Th1 response without affecting the regulatory mechanisms that help control inflammation. In addition, we sequenced the LOC1 genome and performed a genomic characterization. Genomic comparative analysis with the well-known immunomodulatory strains WCSF1 and CRL1506 demonstrated that L. plantarum LOC1 possess a set of adhesion factors and genes involved in the biosynthesis of teichoic acids and lipoproteins that could be involved in its immunomodulatory capacity. The results of this work can contribute to the development of immune-related functional foods containing L. plantarum LOC1.

Styles APA, Harvard, Vancouver, ISO, etc.

49

Ban, Qiuyan, Wenjing Chi, Xiaoxiao Wang, Shiqiong Wang, Dan Hai, Guangshan Zhao, Qiuyan Zhao, Daniel Granato et Xianqing Huang. « (-)-Epigallocatechin-3-Gallate Attenuates the Adverse Reactions Triggered by Selenium Nanoparticles without Compromising Their Suppressing Effect on Peritoneal Carcinomatosis in Mice Bearing Hepatocarcinoma 22 Cells ». Molecules 28, n^o 9 (5 mai 2023) : 3904. http://dx.doi.org/10.3390/molecules28093904.

Texte intégral

Résumé :

Increasing evidence shows that selenium and polyphenols are two types of the most reported compounds in tumor chemoprevention due to their remarkable antitumor activity and high safety profile. The cross-talk between polyphenols and selenium is a hot research topic, and the combination of polyphenols and selenium is a valuable strategy for fighting cancer. The current work investigated the combination anti-peritoneal carcinomatosis (PC) effect of selenium nanoparticles (SeNPs) and green tea (Camellia sinensis) polyphenol (-)-epigallocatechin-3-gallate (EGCG) in mice bearing murine hepatocarcinoma 22 (H22) cells. Results showed that SeNPs alone significantly inhibited cancer cell proliferation and extended the survival time of mice bearing H22 cells. Still, the potential therapeutic efficacy is accompanied by an approximately eighty percent diarrhea rate. When EGCG was combined with SeNPs, EGCG did not affect the tumor proliferation inhibition effect but eliminated diarrhea triggered by SeNPs. In addition, both the intracellular selectively accumulated EGCG without killing effect on cancer cells and the enhanced antioxidant enzyme levels in ascites after EGCG was delivered alone by intraperitoneal injection indicated that H22 cells were insensitive to EGCG. Moreover, EGCG could prevent SeNP-caused systemic oxidative damage by enhancing serum superoxide dismutase, glutathione, and glutathione peroxidase levels in healthy mice. Overall, we found that H22 cells are insensitive to EGCG, but combining EGCG with SeNPs could protect against SeNP-triggered diarrhea without compromising the suppressing efficacy of SeNPs on PC in mice bearing H22 cells and attenuate SeNP-caused systemic toxicity in healthy mice. These results suggest that EGCG could be employed as a promising candidate for preventing the adverse reactions of chemotherapy including chemotherapy-induced diarrhea and systemic toxicity in cancer individuals.

Styles APA, Harvard, Vancouver, ISO, etc.

50

Gonzalez Suarez, Narjara, Yuniel Fernandez-Marrero, Sima Torabidastgerdooei et Borhane Annabi. « EGCG Prevents the Onset of an Inflammatory and Cancer-Associated Adipocyte-like Phenotype in Adipose-Derived Mesenchymal Stem/Stromal Cells in Response to the Triple-Negative Breast Cancer Secretome ». Nutrients 14, n^o 5 (5 mars 2022) : 1099. http://dx.doi.org/10.3390/nu14051099.

Texte intégral

Résumé :

Background: Triple-negative breast cancer (TNBC) cells secretome induces a pro-inflammatory microenvironment within the adipose tissue, which hosts both mature adipocytes and adipose-derived mesenchymal stem/stromal cells (ADMSC). The subsequent acquisition of a cancer-associated adipocyte (CAA)-like phenotype is, however, unknown in ADMSC. While epidemiological studies suggest that consuming a polyphenol-rich diet reduces the incidence of some obesity-related cancers, the chemopreventive impact of green tea-derived epigallocatechin-3-gallate (EGCG) against the cues that trigger the CAA phenotype remain undocumented in ADMSC. Methods: Human ADMSC were exposed to human TNBC-derived MDA-MB-231 conditioned media (TNBC cells secretome) supplemented or not with EGCG. Differential gene expression was assessed through RNA-Seq analysis and confirmed by RT-qPCR. Protein expression levels and the activation status of signal transduction pathways mediators were determined by Western blotting. ADMSC chemotaxis was assessed by a real-time cell migration assay. Results: The TNBC cells secretome induced in ADMSC the expression of the CAA cytokines CCL2, CCL5, IL-1β, and IL-6, and of immunomodulators COX2, HIF-1α, VEGFα, and PD-L1. The epithelial-to-mesenchymal biomarker Snail was found to control the CAA phenotype. EGCG inhibited the induction of CAA genes and the activation status of Smad2 and NF-κB. The induced chemotactic response was also inhibited by EGCG. Conclusion: The induction of an inflammatory and CAA-like phenotype in ADMSC can be triggered by the TNBC cells secretome, while still efficiently prevented by diet-derived polyphenols.

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « Tea triggered »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres